1. The seminar discussed coronary blood flow and myocardial oxygen consumption. Key determinants include heart rate, systolic pressure, and left ventricular contractility.
2. Myocardial oxygen extraction is near maximal at rest, so increases in demand are met by proportional increases in coronary flow and oxygen delivery.
3. Fractional flow reserve measures the ratio of distal coronary pressure to aortic pressure during maximal hyperemia. An FFR below 0.75 is associated with ischemia while above 0.80 is usually not.
The document discusses the physiology of coronary blood flow and the microcirculation. Some key points include:
- Coronary blood flow is determined not only by proximal pressures but also by active compression and decompression of the microcirculation.
- Distal coronary pressure is influenced by both pressure transmitted from the aorta and pressure arising from the microcirculation.
- Fractional flow reserve (FFR) provides a measure of maximum achievable blood flow through a stenosis compared to a normal artery, indicating the functional significance of the stenosis.
- An FFR below 0.80 accurately identifies lesions causing ischemia, while a value above 0.80 reliably excludes ischemia.
The document summarizes key aspects of cardiac catheterization and hemodynamic data collection. It describes the normal cardiac cycle, pressure measurement systems, normal pressure waveforms, methods to measure cardiac output like thermodilution and Fick, how to evaluate valvular stenosis and regurgitation, determine vascular resistance and shunts. Specific details are provided on assessing aortic stenosis, mitral stenosis, right-sided valves and quantifying regurgitant fractions. Oxygen saturation analysis and Fick principles are outlined for shunt determinations.
hemodynamic in cath lab: aortic stenosis and hocmrahul arora
1) Cardiac catheterization can provide key information about aortic stenosis including transvalvular pressure gradients, the level of stenosis, and estimation of valve area.
2) Low-flow, low-gradient aortic stenosis can be further classified as either having a decreased ejection fraction or a paradoxically normal ejection fraction.
3) In hypertrophic cardiomyopathy, cardiac catheterization can identify dynamic intraventricular pressure gradients that may only be provoked with maneuvers like the Valsalva maneuver.
This document discusses fractional flow reserve (FFR), which is a technique used to functionally assess the significance of coronary artery stenosis. FFR is defined as the ratio of maximum blood flow in a stenotic artery to maximum blood flow if there was no stenosis. It is calculated as the ratio of mean distal coronary pressure (Pd) to mean aortic pressure (Pa) during maximal hyperemia induced by pharmacological agents. An FFR value below 0.75 is associated with inducible ischemia, while a value above 0.80 indicates an insignificant stenosis in most cases. FFR has advantages over angiography alone in evaluating stenosis as it accounts for vessel characteristics like length and takes collateral flow into consideration.
This document discusses fractional flow reserve (FFR), a technique used during coronary catheterization to measure pressure differences across a coronary stenosis and determine if it is causing myocardial ischemia. An FFR value below 0.75 is considered functionally significant while a value above 0.80 rules out ischemia. FFR is useful for evaluating single-vessel disease, left main stenosis, tandem lesions, diffuse disease, grafts, and ostial lesions. Limitations include inability to assess plaque morphology.
Assessment of prosthetic valve functionSwapnil Garde
This document discusses the assessment of prosthetic valve function through various imaging modalities. It begins with an introduction to prosthetic valves and outlines topics to be covered, including classification of valve types. Evaluation methods like chest x-ray, fluoroscopy, echocardiography, and CT are described. Parameters assessed on each modality and guidelines for evaluation are provided. Complications of prosthetic valves and 3D imaging advances are also mentioned.
This document discusses various methods for quantifying intracardiac shunts in patients with congenital heart lesions. It describes invasive oximetry and indicator dilution techniques as well as noninvasive Doppler echocardiography methods. For echocardiography, it outlines techniques for quantifying left-to-right shunts using pulmonary and aortic flow measurements, as well as a simplified method using diameter ratios. It also discusses limitations and sources of error for these quantification methods.
The document discusses the physiology of coronary blood flow and the microcirculation. Some key points include:
- Coronary blood flow is determined not only by proximal pressures but also by active compression and decompression of the microcirculation.
- Distal coronary pressure is influenced by both pressure transmitted from the aorta and pressure arising from the microcirculation.
- Fractional flow reserve (FFR) provides a measure of maximum achievable blood flow through a stenosis compared to a normal artery, indicating the functional significance of the stenosis.
- An FFR below 0.80 accurately identifies lesions causing ischemia, while a value above 0.80 reliably excludes ischemia.
The document summarizes key aspects of cardiac catheterization and hemodynamic data collection. It describes the normal cardiac cycle, pressure measurement systems, normal pressure waveforms, methods to measure cardiac output like thermodilution and Fick, how to evaluate valvular stenosis and regurgitation, determine vascular resistance and shunts. Specific details are provided on assessing aortic stenosis, mitral stenosis, right-sided valves and quantifying regurgitant fractions. Oxygen saturation analysis and Fick principles are outlined for shunt determinations.
hemodynamic in cath lab: aortic stenosis and hocmrahul arora
1) Cardiac catheterization can provide key information about aortic stenosis including transvalvular pressure gradients, the level of stenosis, and estimation of valve area.
2) Low-flow, low-gradient aortic stenosis can be further classified as either having a decreased ejection fraction or a paradoxically normal ejection fraction.
3) In hypertrophic cardiomyopathy, cardiac catheterization can identify dynamic intraventricular pressure gradients that may only be provoked with maneuvers like the Valsalva maneuver.
This document discusses fractional flow reserve (FFR), which is a technique used to functionally assess the significance of coronary artery stenosis. FFR is defined as the ratio of maximum blood flow in a stenotic artery to maximum blood flow if there was no stenosis. It is calculated as the ratio of mean distal coronary pressure (Pd) to mean aortic pressure (Pa) during maximal hyperemia induced by pharmacological agents. An FFR value below 0.75 is associated with inducible ischemia, while a value above 0.80 indicates an insignificant stenosis in most cases. FFR has advantages over angiography alone in evaluating stenosis as it accounts for vessel characteristics like length and takes collateral flow into consideration.
This document discusses fractional flow reserve (FFR), a technique used during coronary catheterization to measure pressure differences across a coronary stenosis and determine if it is causing myocardial ischemia. An FFR value below 0.75 is considered functionally significant while a value above 0.80 rules out ischemia. FFR is useful for evaluating single-vessel disease, left main stenosis, tandem lesions, diffuse disease, grafts, and ostial lesions. Limitations include inability to assess plaque morphology.
Assessment of prosthetic valve functionSwapnil Garde
This document discusses the assessment of prosthetic valve function through various imaging modalities. It begins with an introduction to prosthetic valves and outlines topics to be covered, including classification of valve types. Evaluation methods like chest x-ray, fluoroscopy, echocardiography, and CT are described. Parameters assessed on each modality and guidelines for evaluation are provided. Complications of prosthetic valves and 3D imaging advances are also mentioned.
This document discusses various methods for quantifying intracardiac shunts in patients with congenital heart lesions. It describes invasive oximetry and indicator dilution techniques as well as noninvasive Doppler echocardiography methods. For echocardiography, it outlines techniques for quantifying left-to-right shunts using pulmonary and aortic flow measurements, as well as a simplified method using diameter ratios. It also discusses limitations and sources of error for these quantification methods.
Iabp instrumentation, indications and complicationsManu Jacob
1. Intra-aortic balloon counterpulsation (IABP) provides temporary circulatory support through systolic unloading and diastolic augmentation.
2. IABP is commonly used for patients in cardiogenic shock, high-risk PCI, and as a bridge to cardiac transplantation.
3. Contraindications include aortic insufficiency, aneurysm, and dissection. Complications include limb ischemia and thromboembolism.
The document discusses the history, anatomy, angiographic views, variations, and clinical relevance of coronary arteries. It provides a detailed overview of the typical anatomy and branches of the left main, left anterior descending, left circumflex, and right coronary arteries. It also describes common anatomical variations and anomalies seen in coronary arteries and their clinical implications. Angiographic classification methods for different coronary artery segments are presented.
Various coronary physiological measurements can be made in the cardiac catheterization laboratory using sensor-tipped guidewires; they include the measurement of poststenotic absolute coronary flow reserve, the relative coronary flow reserve, and the pressure-derived fractional flow reserve of the myocardium. Ambiguity regarding abnormal microcirculation has been reduced or eliminated with measurements of relative coronary flow reserve and fractional flow reserve. The role of microvascular flow impairment can be separately determined with coronary flow velocity reserve measurements. In addition to lesion assessment before and after intervention, emerging applications of coronary physiology include the determination of physiological responses to new pharmacological agents, such as glycoprotein IIb/IIIa blockers, in patients with acute myocardial infarction. Measurements of coronary physiology in the catheterization laboratory provide objective data that complement angiography for clinical decision-making
This document discusses the echocardiographic evaluation of mitral valve prolapse (MVP). It describes the use of M-mode, 2D, and 3D echocardiography to diagnose MVP and assess mitral regurgitation severity. Measurement of the vena contracta and use of the proximal isovelocity surface area method are emphasized for accurate regurgitant quantification. Surgical indications and repair techniques are also summarized.
This document discusses coronary blood flow physiology, including the determinants of coronary resistance, autoregulation, microcirculation, and how blood flow is affected by exercise and the presence of coronary stenosis. It covers topics like the three resistance beds, flow-mediated dilation, metabolic mediators, neural and paracrine control, and the pushing and suction wave mechanism of diastolic flow. Measurement techniques and abnormalities in blood flow with normal coronary arteries are also briefly mentioned.
This document summarizes the evaluation of aortic valve stenosis using echocardiography. It describes the normal aortic valve anatomy and various types of aortic valve stenosis including calcific, bicuspid, rheumatic, and supravalvular or subvalvular stenosis. Doppler echocardiography is used to evaluate aortic valve stenosis severity based on valve area, mean gradient, and peak jet velocity. Stress echocardiography with dobutamine can help distinguish true severe from pseudo-severe low-flow, low-gradient aortic stenosis.
This document discusses contrast echocardiography, including the mechanism by which microbubble contrast agents improve echocardiographic imaging. Ideal contrast agents are described as being safe, metabolically inert, long-lasting, strong sound reflectors that are small enough to pass through capillaries. Several FDA-approved second generation contrast agents are mentioned along with their shell materials and gases. Optimal echocardiographic settings for contrast imaging are outlined. Clinical applications of contrast echocardiography include assessing shunts, venous anomalies, and leaks. Examples of its use in specific cases are provided.
There are three types of cannulations used in cardiopulmonary bypass (CPB): arterial, venous, and cardioplegia cannulation. The target for venous cannulation is generally the right atrium, while the target for the arterial cannula is the ascending aorta. Venous blood is diverted from the superior and inferior vena cavae to the oxygenator via flexible plastic cannulas inserted into the venae cavae or right atrium. Cardioplegia cannulas are used to deliver cardioplegia solution to the patient's heart.
This document summarizes the echocardiographic assessment of mitral stenosis (MS). It describes the anatomy of the mitral valve and causes of MS. Methods for assessing MS severity include measuring the pressure gradient, mitral valve area using planimetry and pressure half-time, and pulmonary artery pressure. Suitability for percutaneous transvenous mitral commissurotomy is evaluated. Concomitant valve lesions are also identified. Stress echocardiography may be used when symptoms are equivocal. Transesophageal echocardiography is recommended in some cases.
Contrast echocardiography uses microbubble ultrasound contrast agents to improve image quality. These microbubbles remain in the intravascular space and allow for assessment of cardiac structure, function, and perfusion. Second generation contrast agents use an inert gas encapsulated by albumin or phospholipid shells. They interact with ultrasound by reflecting at fundamental frequencies and resonating to produce harmonic frequencies. Continuous infusion provides steady contrast levels needed for perfusion assessment. Contrast echocardiography is a non-invasive technique that improves evaluation of the heart.
Echo assessment of lv systolic function and swmaFuad Farooq
This document discusses various techniques for assessing left ventricular systolic function using echocardiography, including:
- Visual assessment of endocardial motion and wall thickening to evaluate global and regional function
- Quantitative measures like fractional shortening, ejection fraction, and volumes
- Tissue Doppler imaging of mitral annular velocities
- Tissue tracking and strain imaging to evaluate timing and extent of myocardial contraction
- Wall motion scoring to characterize regional abnormalities
Low flow Low gradient severe aortic stenosisAnuj Mehta
1) Low flow, low gradient severe aortic stenosis can occur with both low and preserved ejection fraction. Dobutamine stress echocardiography is important to differentiate true from pseudo-severe stenosis.
2) For low ejection fraction, aortic valve replacement is recommended irrespective of symptoms or flow reserve.
3) For preserved ejection fraction, alternatives to ejection fraction like valvulo-arterial impedance and global longitudinal strain can help identify intrinsic myocardial dysfunction and predict outcomes. Aortic valve replacement may be better than medical management in these patients.
Echocardiographic Evaluation of LV Diastolic FunctionJunhao Koh
The document discusses methods for evaluating left ventricular diastolic function using echocardiography. It describes the four phases of diastole, parameters used to assess diastolic function including mitral inflow patterns, mitral annular tissue Doppler, pulmonary vein flow, left atrial size and the Tei index. Grades of diastolic dysfunction and approaches from ASE/EAE and Mayo Clinic are summarized. Continuous wave Doppler of aortic regurgitation is also presented as a noninvasive method to evaluate left ventricular relaxation.
1) Pressure tracing of the left ventricle involves using fluid-filled catheters connected to pressure transducers to record intracardiac pressures. Factors such as catheter size, damping, and natural frequency determine recording quality.
2) Sources of error in pressure measurements include catheter whip, end-pressure artifacts, and deterioration of frequency response. Invasive monitoring is useful for evaluating conditions like aortic stenosis and mitral stenosis when noninvasive data is discrepant or unclear.
3) Distinguishing constrictive pericarditis from restrictive cardiomyopathy involves assessing ventricular interdependence, pulmonary pressures, and left ventricular pressure tracings. Hemodynamic data aids in diagnosis and management of many conditions.
This document discusses various echocardiographic scoring systems used to assess mitral valve anatomy and predict outcomes of percutaneous balloon mitral valvuloplasty (PBMV). The Wilkins score and Commissural Calcification score are described in detail. The Wilkins score grades leaflet thickening, mobility, calcification and subvalvular involvement on a scale of 4-16. A score ≤8 indicates favorable anatomy for PBMV. The Commissural Calcification score quantifies calcification at each commissure. Other discussed scores include the Cormier score, RT-3DE score, Chen score, Reid score and Nobuyoshi score. Limitations of the scoring systems and ideas for an ideal future scoring
This is a comprehensive description of coronay lesion assessment from routinely used angiography to advanced imaging modalities like IVUS/OCT including their functional significance by FFR
This document summarizes dobutamine stress echocardiography (DSE). Key points include:
- DSE uses the drug dobutamine to simulate exercise and increase heart rate, contractility, and myocardial oxygen demand to detect ischemia.
- It is useful for evaluating ischemia, viability, and valvular dysfunction in patients unable to exercise.
- The document reviews the DSE protocol, interpretation of wall motion abnormalities, indications, side effects, and applications for assessing ischemic heart disease, viability, valvular stenosis like mitral and aortic stenosis, and pulmonary hypertension.
Guide catheters in coronary interventionRohitWalse2
Guide catheters are essential for coronary interventions as they deliver hardware into the arteries. The document discusses the properties and types of guide catheters, highlighting how their structure provides support and torque control. It describes commonly used guide catheters like the Judkins, Amplatz and EBU catheters, noting what vessels each is best suited for. Specialty guide catheters for difficult anatomies are also reviewed. Proper guide selection and positioning are emphasized for coaxial engagement and optimal device delivery during interventions.
The document discusses guidelines for assessing diastolic dysfunction according to the ASE/EACVI 2016 guidelines. It defines diastolic dysfunction and describes the stages from grade I to grade IV. For each grade, it discusses the pathophysiology and key echocardiographic findings including mitral inflow patterns, tissue Doppler measurements, pulmonary vein flow, and left atrial size. The guidelines simplify the assessment of diastolic function into four grades based on parameters of left ventricular relaxation, left atrial pressure, mitral E/A ratio, E/e' ratio, pulmonary vein flow, and left atrial size.
This document provides an overview of echocardiographic assessment of mitral regurgitation. It describes the anatomy of the mitral valve including the leaflets, annulus, chordae, and papillary muscles. It discusses Carpentier's functional classification system for describing the mechanism of mitral valve dysfunction. Methods for assessing severity are covered, including color flow imaging, continuous wave Doppler, vena contracta width, proximal isovelocity surface area, and volumetric assessment. Key points are made about evaluating jet direction, duration, and velocity in context of blood pressure. The importance of assessing left ventricular and left atrial size and function is also highlighted.
1) The document discusses coronary physiology, including unique features of coronary blood flow such as its phasic nature and determinants of myocardial oxygen consumption.
2) It describes the coronary pressure-flow relationship and factors that influence coronary vascular resistance such as epicardial arteries, microcirculatory resistance arteries, and extravascular compression.
3) Fractional flow reserve (FFR) is introduced as a technique to assess the physiological significance of coronary artery stenosis using pressure measurements taken during maximal hyperemia. An FFR value below 0.75 is generally associated with inducible ischemia.
The document summarizes key aspects of coronary blood flow regulation and determinants of myocardial oxygen consumption. It discusses how:
1) Myocardial contraction and oxygen delivery are closely linked, and the balance between oxygen supply and demand is critical for normal heart function.
2) The major determinants of myocardial oxygen consumption are heart rate, systolic pressure, and left ventricular contractility. Increases in these factors require proportional increases in coronary flow and oxygen delivery.
3) Coronary vascular resistance has three main components - epicardial conduit resistance, microcirculatory resistance, and extravascular compressive resistance which varies through the cardiac cycle. Maintaining the balance of these factors is important for adequate oxygen supply
Iabp instrumentation, indications and complicationsManu Jacob
1. Intra-aortic balloon counterpulsation (IABP) provides temporary circulatory support through systolic unloading and diastolic augmentation.
2. IABP is commonly used for patients in cardiogenic shock, high-risk PCI, and as a bridge to cardiac transplantation.
3. Contraindications include aortic insufficiency, aneurysm, and dissection. Complications include limb ischemia and thromboembolism.
The document discusses the history, anatomy, angiographic views, variations, and clinical relevance of coronary arteries. It provides a detailed overview of the typical anatomy and branches of the left main, left anterior descending, left circumflex, and right coronary arteries. It also describes common anatomical variations and anomalies seen in coronary arteries and their clinical implications. Angiographic classification methods for different coronary artery segments are presented.
Various coronary physiological measurements can be made in the cardiac catheterization laboratory using sensor-tipped guidewires; they include the measurement of poststenotic absolute coronary flow reserve, the relative coronary flow reserve, and the pressure-derived fractional flow reserve of the myocardium. Ambiguity regarding abnormal microcirculation has been reduced or eliminated with measurements of relative coronary flow reserve and fractional flow reserve. The role of microvascular flow impairment can be separately determined with coronary flow velocity reserve measurements. In addition to lesion assessment before and after intervention, emerging applications of coronary physiology include the determination of physiological responses to new pharmacological agents, such as glycoprotein IIb/IIIa blockers, in patients with acute myocardial infarction. Measurements of coronary physiology in the catheterization laboratory provide objective data that complement angiography for clinical decision-making
This document discusses the echocardiographic evaluation of mitral valve prolapse (MVP). It describes the use of M-mode, 2D, and 3D echocardiography to diagnose MVP and assess mitral regurgitation severity. Measurement of the vena contracta and use of the proximal isovelocity surface area method are emphasized for accurate regurgitant quantification. Surgical indications and repair techniques are also summarized.
This document discusses coronary blood flow physiology, including the determinants of coronary resistance, autoregulation, microcirculation, and how blood flow is affected by exercise and the presence of coronary stenosis. It covers topics like the three resistance beds, flow-mediated dilation, metabolic mediators, neural and paracrine control, and the pushing and suction wave mechanism of diastolic flow. Measurement techniques and abnormalities in blood flow with normal coronary arteries are also briefly mentioned.
This document summarizes the evaluation of aortic valve stenosis using echocardiography. It describes the normal aortic valve anatomy and various types of aortic valve stenosis including calcific, bicuspid, rheumatic, and supravalvular or subvalvular stenosis. Doppler echocardiography is used to evaluate aortic valve stenosis severity based on valve area, mean gradient, and peak jet velocity. Stress echocardiography with dobutamine can help distinguish true severe from pseudo-severe low-flow, low-gradient aortic stenosis.
This document discusses contrast echocardiography, including the mechanism by which microbubble contrast agents improve echocardiographic imaging. Ideal contrast agents are described as being safe, metabolically inert, long-lasting, strong sound reflectors that are small enough to pass through capillaries. Several FDA-approved second generation contrast agents are mentioned along with their shell materials and gases. Optimal echocardiographic settings for contrast imaging are outlined. Clinical applications of contrast echocardiography include assessing shunts, venous anomalies, and leaks. Examples of its use in specific cases are provided.
There are three types of cannulations used in cardiopulmonary bypass (CPB): arterial, venous, and cardioplegia cannulation. The target for venous cannulation is generally the right atrium, while the target for the arterial cannula is the ascending aorta. Venous blood is diverted from the superior and inferior vena cavae to the oxygenator via flexible plastic cannulas inserted into the venae cavae or right atrium. Cardioplegia cannulas are used to deliver cardioplegia solution to the patient's heart.
This document summarizes the echocardiographic assessment of mitral stenosis (MS). It describes the anatomy of the mitral valve and causes of MS. Methods for assessing MS severity include measuring the pressure gradient, mitral valve area using planimetry and pressure half-time, and pulmonary artery pressure. Suitability for percutaneous transvenous mitral commissurotomy is evaluated. Concomitant valve lesions are also identified. Stress echocardiography may be used when symptoms are equivocal. Transesophageal echocardiography is recommended in some cases.
Contrast echocardiography uses microbubble ultrasound contrast agents to improve image quality. These microbubbles remain in the intravascular space and allow for assessment of cardiac structure, function, and perfusion. Second generation contrast agents use an inert gas encapsulated by albumin or phospholipid shells. They interact with ultrasound by reflecting at fundamental frequencies and resonating to produce harmonic frequencies. Continuous infusion provides steady contrast levels needed for perfusion assessment. Contrast echocardiography is a non-invasive technique that improves evaluation of the heart.
Echo assessment of lv systolic function and swmaFuad Farooq
This document discusses various techniques for assessing left ventricular systolic function using echocardiography, including:
- Visual assessment of endocardial motion and wall thickening to evaluate global and regional function
- Quantitative measures like fractional shortening, ejection fraction, and volumes
- Tissue Doppler imaging of mitral annular velocities
- Tissue tracking and strain imaging to evaluate timing and extent of myocardial contraction
- Wall motion scoring to characterize regional abnormalities
Low flow Low gradient severe aortic stenosisAnuj Mehta
1) Low flow, low gradient severe aortic stenosis can occur with both low and preserved ejection fraction. Dobutamine stress echocardiography is important to differentiate true from pseudo-severe stenosis.
2) For low ejection fraction, aortic valve replacement is recommended irrespective of symptoms or flow reserve.
3) For preserved ejection fraction, alternatives to ejection fraction like valvulo-arterial impedance and global longitudinal strain can help identify intrinsic myocardial dysfunction and predict outcomes. Aortic valve replacement may be better than medical management in these patients.
Echocardiographic Evaluation of LV Diastolic FunctionJunhao Koh
The document discusses methods for evaluating left ventricular diastolic function using echocardiography. It describes the four phases of diastole, parameters used to assess diastolic function including mitral inflow patterns, mitral annular tissue Doppler, pulmonary vein flow, left atrial size and the Tei index. Grades of diastolic dysfunction and approaches from ASE/EAE and Mayo Clinic are summarized. Continuous wave Doppler of aortic regurgitation is also presented as a noninvasive method to evaluate left ventricular relaxation.
1) Pressure tracing of the left ventricle involves using fluid-filled catheters connected to pressure transducers to record intracardiac pressures. Factors such as catheter size, damping, and natural frequency determine recording quality.
2) Sources of error in pressure measurements include catheter whip, end-pressure artifacts, and deterioration of frequency response. Invasive monitoring is useful for evaluating conditions like aortic stenosis and mitral stenosis when noninvasive data is discrepant or unclear.
3) Distinguishing constrictive pericarditis from restrictive cardiomyopathy involves assessing ventricular interdependence, pulmonary pressures, and left ventricular pressure tracings. Hemodynamic data aids in diagnosis and management of many conditions.
This document discusses various echocardiographic scoring systems used to assess mitral valve anatomy and predict outcomes of percutaneous balloon mitral valvuloplasty (PBMV). The Wilkins score and Commissural Calcification score are described in detail. The Wilkins score grades leaflet thickening, mobility, calcification and subvalvular involvement on a scale of 4-16. A score ≤8 indicates favorable anatomy for PBMV. The Commissural Calcification score quantifies calcification at each commissure. Other discussed scores include the Cormier score, RT-3DE score, Chen score, Reid score and Nobuyoshi score. Limitations of the scoring systems and ideas for an ideal future scoring
This is a comprehensive description of coronay lesion assessment from routinely used angiography to advanced imaging modalities like IVUS/OCT including their functional significance by FFR
This document summarizes dobutamine stress echocardiography (DSE). Key points include:
- DSE uses the drug dobutamine to simulate exercise and increase heart rate, contractility, and myocardial oxygen demand to detect ischemia.
- It is useful for evaluating ischemia, viability, and valvular dysfunction in patients unable to exercise.
- The document reviews the DSE protocol, interpretation of wall motion abnormalities, indications, side effects, and applications for assessing ischemic heart disease, viability, valvular stenosis like mitral and aortic stenosis, and pulmonary hypertension.
Guide catheters in coronary interventionRohitWalse2
Guide catheters are essential for coronary interventions as they deliver hardware into the arteries. The document discusses the properties and types of guide catheters, highlighting how their structure provides support and torque control. It describes commonly used guide catheters like the Judkins, Amplatz and EBU catheters, noting what vessels each is best suited for. Specialty guide catheters for difficult anatomies are also reviewed. Proper guide selection and positioning are emphasized for coaxial engagement and optimal device delivery during interventions.
The document discusses guidelines for assessing diastolic dysfunction according to the ASE/EACVI 2016 guidelines. It defines diastolic dysfunction and describes the stages from grade I to grade IV. For each grade, it discusses the pathophysiology and key echocardiographic findings including mitral inflow patterns, tissue Doppler measurements, pulmonary vein flow, and left atrial size. The guidelines simplify the assessment of diastolic function into four grades based on parameters of left ventricular relaxation, left atrial pressure, mitral E/A ratio, E/e' ratio, pulmonary vein flow, and left atrial size.
This document provides an overview of echocardiographic assessment of mitral regurgitation. It describes the anatomy of the mitral valve including the leaflets, annulus, chordae, and papillary muscles. It discusses Carpentier's functional classification system for describing the mechanism of mitral valve dysfunction. Methods for assessing severity are covered, including color flow imaging, continuous wave Doppler, vena contracta width, proximal isovelocity surface area, and volumetric assessment. Key points are made about evaluating jet direction, duration, and velocity in context of blood pressure. The importance of assessing left ventricular and left atrial size and function is also highlighted.
1) The document discusses coronary physiology, including unique features of coronary blood flow such as its phasic nature and determinants of myocardial oxygen consumption.
2) It describes the coronary pressure-flow relationship and factors that influence coronary vascular resistance such as epicardial arteries, microcirculatory resistance arteries, and extravascular compression.
3) Fractional flow reserve (FFR) is introduced as a technique to assess the physiological significance of coronary artery stenosis using pressure measurements taken during maximal hyperemia. An FFR value below 0.75 is generally associated with inducible ischemia.
The document summarizes key aspects of coronary blood flow regulation and determinants of myocardial oxygen consumption. It discusses how:
1) Myocardial contraction and oxygen delivery are closely linked, and the balance between oxygen supply and demand is critical for normal heart function.
2) The major determinants of myocardial oxygen consumption are heart rate, systolic pressure, and left ventricular contractility. Increases in these factors require proportional increases in coronary flow and oxygen delivery.
3) Coronary vascular resistance has three main components - epicardial conduit resistance, microcirculatory resistance, and extravascular compressive resistance which varies through the cardiac cycle. Maintaining the balance of these factors is important for adequate oxygen supply
This document discusses the physiology of the coronary circulation. It covers topics like microvascular anatomy, determinants of coronary blood flow and myocardial oxygen consumption, coronary autoregulation, and control of coronary vascular resistance. The coronary circulation balances oxygen supply and demand in the heart. Coronary blood flow increases during diastole to perfuse the heart muscle. Myocardial oxygen consumption is determined by factors like heart rate, blood pressure, and contractility. The coronary system maintains blood flow over a range of pressures via autoregulation. Endothelial cells, nerves, metabolites, and physical forces regulate resistance in small coronary vessels.
Coronary Blood Flow and Myocardial Ischemia.pptxJohn Smith
This document summarizes key concepts regarding coronary blood flow and myocardial ischemia from Braunwald's Heart Disease, 12th edition. It discusses how coronary blood flow is regulated and the determinants of myocardial oxygen demand. When oxygen supply and demand are disrupted by diseases affecting coronary blood flow, a vicious cycle of ischemia can result. Knowledge of coronary flow regulation, oxygen demand factors, and the relationship between ischemia and contraction is essential to understanding myocardial ischemia.
This document discusses hemorrhage and hemorrhagic shock. It begins by describing the different types of hemorrhage and provides estimates for blood loss. It then discusses signs of hemorrhage like tachycardia and decreased blood pressure. Classes of hemorrhagic shock are defined based on percentage of blood volume lost and associated vital signs. Investigations like blood work and imaging are outlined. Principles of fluid resuscitation are provided, including types of fluids to use and transfusion thresholds. Damage control surgery is also briefly mentioned.
The document discusses coronary circulation and coronary artery disease. It begins by describing the anatomy of the coronary blood vessels and the blood supply to the heart. It then discusses characteristics of coronary blood flow such as autoregulation and factors that regulate it like metabolites and nervous control. Measurement techniques for coronary blood flow are also outlined. The document concludes by describing coronary artery disease conditions like angina and myocardial infarction as well as treatments.
coronarycirculation. and peculiarities,regulationpptxReena Gollapalli
The document provides information on the coronary circulation system. It discusses the following key points in 3 sentences:
The two coronary arteries arise from the aorta and supply blood to the myocardium. The right coronary artery supplies blood mainly to the right ventricle and portions of the left ventricle and septum, while the left coronary artery supplies blood to the left ventricle, left atrium, and part of the septum. Coronary blood flow is highest during diastole when the heart muscles relax and lowest during systole when tension in the left ventricle causes throttling of the coronary arteries.
This document summarizes key concepts in cardiovascular physiology including:
1. Determinants of cardiac output which are stroke volume and heart rate. Stroke volume is determined by preload, afterload, and contractility as described by Frank-Starling law of the heart.
2. Control of arterial blood pressure involves immediate control by baroreceptors and chemoreceptors, intermediate control by the renin-angiotensin-aldosterone system and atrial natriuretic peptide, and long-term control through sodium and water retention in the kidneys.
3. Coronary physiology includes characteristics of coronary blood flow such as intermittent flow, autoregulation to maintain flow, and metabolic and
The circulatory system transports blood throughout the body to deliver nutrients and oxygen to tissues and remove waste. It is divided into systemic and pulmonary circulation. Blood flows from arteries to arterioles and capillaries, where gas and nutrient exchange occurs, then to venules and veins, which return blood to the heart. Precise control of blood flow to each tissue is critical to meet metabolic demands.
This document provides an overview of blood and lymph flow dynamics. It begins by introducing the circulatory system and its functional parts including arteries, arterioles, capillaries, venules and veins. It then discusses hemodynamics and the factors that influence blood flow such as arterial pressure, vessel diameter, blood viscosity and velocity. The document also covers the lymphatic system and lymph formation and flow. It concludes by mentioning some lymphatic disorders and references.
This document discusses the basic principles of arterial hemodynamics and its clinical application in arterial disease. It covers topics such as fluid pressure and energy, Bernoulli's principle, fluid energy losses due to viscosity and inertia, vascular resistance, blood flow patterns, the effects of stenosis, collateral circulation, and the impact of exercise therapy, vasodilators, sympathectomy, vascular steal, and gravity on arterial hemodynamics and blood flow.
This document discusses the physiological basis of coronary revascularization. It covers topics such as coronary physiology, myocardial viability assessment, and coronary revascularization. Some key points include:
- Coronary blood flow is proportional to perfusion pressure over resistance and is regulated by various metabolic and endothelial factors.
- Myocardial ischemia occurs when oxygen demand exceeds supply. Coronary autoregulation and flow reserve help maintain adequate flow.
- Myocardial viability refers to dysfunctional tissue with limited scarring that has potential for functional recovery after revascularization through mechanisms like stunned myocardium and hibernation.
- Various techniques can assess viability including cardiac imaging and evaluating improvement in function after revascularization. Viability assessment aids decisions about revascularization
Mitral stenosis is a narrowing of the mitral valve that occurs most commonly as a result of rheumatic fever. It is characterized by thickening and scarring of the mitral valve leaflets that causes the opening to narrow over time. The narrowing obstructs blood flow from the left atrium to the left ventricle, causing elevated pressures in the left atrium and lungs. Common symptoms include shortness of breath, cough, hemoptysis, and right-sided heart failure. Diagnosis is made through echocardiogram and treatment involves medications, balloon valvuloplasty, or valve replacement surgery depending on severity.
The document provides information on renal haemodynamics and glomerular filtration. It discusses the following key points:
1. The kidneys receive a large blood flow equivalent to 1/5 of cardiac output to support high rates of glomerular filtration for regulating fluid and solute concentrations.
2. Glomerular filtration rate is determined by the net filtration pressure and glomerular capillary filtration coefficient.
3. Factors that can decrease GFR include increased efferent arteriolar resistance, increased Bowman's capsule pressure, increased glomerular capillary colloid osmotic pressure, and decreased glomerular capillary hydrostatic pressure.
4. The sympathetic nervous system and
Echocardiographic evaluation of mitral regurgitationsruthiMeenaxshiSR
This document discusses the echocardiographic evaluation of mitral regurgitation. It begins by listing common causes of MR such as mitral valve prolapse, rheumatic heart disease, and cardiomyopathy. It then outlines the indications for echocardiography in diagnosing and assessing the severity of MR. Key aspects of the echocardiogram are described such as the Carpentier classification of valve abnormalities, Doppler methods for grading severity including jet area and vena contracta width, and structural parameters like left atrial and ventricular size. Quantitative measurements using the PISA method to calculate regurgitant volume and orifice area are also summarized.
The pulmonary circulation transports deoxygenated blood from the right ventricle to the lungs where carbon dioxide is released and oxygen is absorbed. The pulmonary arteries branch extensively and have large diameters to accommodate the stroke volume from the right ventricle with low resistance. Blood flows through the pulmonary capillaries where gas exchange occurs before returning to the left atrium via the pulmonary veins. Regional blood flow is highest in the lower lungs and intermittent in the apices due to hydrostatic pressures. During exercise, blood flow increases throughout the lungs. Pulmonary edema can result from increased capillary pressure from left heart failure.
This document discusses pericardial diseases and various conditions that affect the pericardium. It begins by describing normal pericardial fluid volume and ventricular interdependence under normal conditions. It then discusses the history of using ultrasound to image the pericardium. Various pathological conditions are covered, including increased pericardial thickness in constrictive pericarditis, how intrapericardial pressure changes with fluid volume and pericardial stiffness, and signs of cardiac tamponade seen on echocardiogram like right atrial and ventricular collapse and IVC plethora. Finally, it describes the presentation of effusive-constrictive pericarditis.
Surgical procedures for congenital heart diseases basicsSachin Sondhi
This document discusses surgical procedures for several congenital heart diseases, including modified Blalock-Taussig shunt (BT) vs classical BT, repair of tetralogy of Fallot (TOF), palliative procedures for TOF, indications and timing for complete TOF repair, repair of TOF with small pulmonary arteries using BT shunt, long term survival after TOF repair, Ebstein's anomaly indications and procedures, D-transposition of great arteries with ventricular septal defect and pulmonary stenosis repair, and Rastelli procedure details. Key details provided include success rates, complications risks, and considerations for various procedures.
Primary Pulmonary HTN Seminar on 19/11/2018
The seminar covered topics related to pulmonary hypertension (PH) including definitions, epidemiology, challenges in diagnosis and treatment, anatomy, pathobiology, genetics, and clinical presentation. PH is defined as a mean pulmonary arterial pressure of >25 mmHg and can be caused by various underlying disorders. Delayed diagnosis and treatment are common problems. The diagnosis requires right heart catheterization, though this test is underutilized. Guidelines for treatment are not always followed consistently.
Pathophysiology of aortic regurgitation and managementSachin Sondhi
This document summarizes a seminar on aortic regurgitation presented by Dr. Sachin Sondhi at IGMC Shimla on 13/08/2018. It discusses the causes and pathology of aortic regurgitation, including degenerative aortic dilation and diseases like Marfan syndrome. The pathophysiology of compensated and decompensated aortic regurgitation is explained. Physical exam findings like murmurs, pulse characteristics, and signs of heart failure are outlined. Symptoms may be initially absent but later include angina, dyspnea, and heart failure.
Pathophysiology of aortic regurgitation and managementSachin Sondhi
This document summarizes a seminar on aortic regurgitation presented by Dr. Sachin Sondhi at IGMC Shimla on 13/08/2018. It discusses the causes and pathology of aortic regurgitation, including degenerative aortic dilation and diseases affecting the aortic valve and root. The pathophysiology and hemodynamic changes in compensated and decompensated aortic regurgitation are explained. Symptoms, physical exam findings, murmurs and natural history are outlined. Indications for surgery include symptomatic patients or asymptomatic patients with reduced ejection fraction or severe left ventricular dilation. Vasodilator therapy may help preserve left ventricular function in some cases.
This document provides information on familial hypercholesterolemia (FH), including its definition, diagnostic criteria, clinical features, screening recommendations, and treatment. FH is a common genetic disorder characterized by elevated LDL cholesterol levels and a high risk of premature coronary heart disease. The majority of FH cases are caused by mutations in the LDLR gene. Diagnosis is based on clinical criteria including family and personal history of early heart disease as well as elevated LDL levels. Screening involves targeted screening of those with a family history as well as cascade screening of relatives. Treatment focuses on aggressively lowering LDL levels through lifestyle changes and cholesterol-lowering medications to reduce heart disease risk.
This document summarizes the mechanisms of cardiac arrhythmias. It describes normal cardiac electrophysiology and the five phases of the cardiac action potential. It then discusses mechanisms that can disrupt normal rhythms, including altered automaticity, triggered activity due to afterdepolarizations, and reentry due to conduction blocks or barriers that allow circuits to form. Key features that help distinguish automatic from triggered from reentrant arrhythmias are described.
- Two strategies are used to manage patients with unstable angina/non-ST-elevation myocardial infarction (UA/NSTEMI): an early invasive strategy involving prompt coronary angiography and revascularization, or a conservative strategy using medical therapy and invasive procedures only for recurrent ischemia.
- A meta-analysis of 8 randomized controlled trials found that an early invasive strategy significantly reduced the composite of death, myocardial infarction, and rehospitalization for acute coronary syndrome compared to conservative care at 6 months follow-up in patients presenting with UA, but not in those with NSTEMI alone.
- From randomization to discharge, an early invasive strategy was associated with higher rates of the composite endpoint in both UA/N
A 24-year-old female presented with abnormal body movements and was found to have hypocalcemia. Laboratory workup showed low serum calcium, high phosphorus, and normal parathyroid hormone. She was diagnosed with hypoparathyroidism and treated with calcium supplementation, resulting in symptom improvement. The cause was determined to be idiopathic hypoparathyroidism.
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
ANAMOLOUS SECONDARY GROWTH IN DICOT ROOTS.pptxRASHMI M G
Abnormal or anomalous secondary growth in plants. It defines secondary growth as an increase in plant girth due to vascular cambium or cork cambium. Anomalous secondary growth does not follow the normal pattern of a single vascular cambium producing xylem internally and phloem externally.
Nucleophilic Addition of carbonyl compounds.pptxSSR02
Nucleophilic addition is the most important reaction of carbonyls. Not just aldehydes and ketones, but also carboxylic acid derivatives in general.
Carbonyls undergo addition reactions with a large range of nucleophiles.
Comparing the relative basicity of the nucleophile and the product is extremely helpful in determining how reversible the addition reaction is. Reactions with Grignards and hydrides are irreversible. Reactions with weak bases like halides and carboxylates generally don’t happen.
Electronic effects (inductive effects, electron donation) have a large impact on reactivity.
Large groups adjacent to the carbonyl will slow the rate of reaction.
Neutral nucleophiles can also add to carbonyls, although their additions are generally slower and more reversible. Acid catalysis is sometimes employed to increase the rate of addition.
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...AbdullaAlAsif1
The pygmy halfbeak Dermogenys colletei, is known for its viviparous nature, this presents an intriguing case of relatively low fecundity, raising questions about potential compensatory reproductive strategies employed by this species. Our study delves into the examination of fecundity and the Gonadosomatic Index (GSI) in the Pygmy Halfbeak, D. colletei (Meisner, 2001), an intriguing viviparous fish indigenous to Sarawak, Borneo. We hypothesize that the Pygmy halfbeak, D. colletei, may exhibit unique reproductive adaptations to offset its low fecundity, thus enhancing its survival and fitness. To address this, we conducted a comprehensive study utilizing 28 mature female specimens of D. colletei, carefully measuring fecundity and GSI to shed light on the reproductive adaptations of this species. Our findings reveal that D. colletei indeed exhibits low fecundity, with a mean of 16.76 ± 2.01, and a mean GSI of 12.83 ± 1.27, providing crucial insights into the reproductive mechanisms at play in this species. These results underscore the existence of unique reproductive strategies in D. colletei, enabling its adaptation and persistence in Borneo's diverse aquatic ecosystems, and call for further ecological research to elucidate these mechanisms. This study lends to a better understanding of viviparous fish in Borneo and contributes to the broader field of aquatic ecology, enhancing our knowledge of species adaptations to unique ecological challenges.
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
2. • The resting coronary blood flow is 0.7-1 ml/min/gm
• Myocardial oxygen consumption --- balance between
supply and demand
• According to Fick’s principle, oxygen consumption in an
organ is equal to the product of regional blood flow
and oxygen extraction capacity.
• The heart is unique in having a maximal resting O2
extraction (~70-80%)
• So, MVO2 = CBF * CaO2
4. • MYOCARDIAL OXYGEN CONSUMPTION
• In contrast to most other vascular beds, myocardial oxygen
extraction is near-maximal at rest, averaging approximately
75% of arterial oxygen content.
• Increases in myocardial oxygen consumption are primarily
met by proportional
increases in coronary flow and
oxygen delivery.
• In addition to coronary flow, oxygen delivery is
directly determined by arterial oxygen content (Cao2)
(depends on HB, spO2 and PaO2)
5. The major determinants of myocardial oxygen
consumption are
• heart rate,
• systolic pressure (or myocardial wall stress),
and
• left ventricular (LV) contractility.
• A twofold increase in any of these individual
determinants of oxygen consumption requires
an approximately 50% increase in coronary
flow.
6. • Myocardial oxygen consumption is 6-
8ml/min/100gm
• 60% is used in force generation, 15% in
myocardial relaxation, 3-5% for electrical
activation and 20% for basal cellular
metabolism
7. Auto regulation
• Regional coronary blood flow remains constant
as coronary artery pressure is reduced below
aortic pressure over a wide range when the
determinants of myocardial oxygen
consumption are kept constant. This
phenomenon is termed autoregulation
• When pressure falls to the lower limit of
autoregulation, coronary resistance arteries are
maximally vasodilated to intrinsic stimuli, and
flow becomes pressure-dependent, resulting in
the onset of subendocardial ischemia
8.
9. • Flow in the maximally vasodilated heart is dependent on
coronary arterial pressure.
• Maximum perfusion and coronary reserve are reduced
- when the diastolic time available for subendocardial
perfusion is decreased (tachycardia) or
- the compressive determinants of diastolic perfusion
(preload) are increased.
- anything that increases resting flow, including increases
in the hemodynamic determinants of oxygen consumption
(systolic pressure, heart rate, contractility) and reductions
in arterial oxygen supply (anemia, hypoxia).
• Thus, circumstances can develop that precipitate
subendocardial ischemia in the presence of normal
coronary arteries
10. • Subendocardial flow primarily
occurs in diastole and begins
to decrease below a mean
coronary pressure of 40 mm
Hg.
• In contrast, subepicardial flow
occurs throughout the cardiac
cycle and is maintained until
coronary pressure falls below
25 mm Hg.
• This difference arises from
increased oxygen
consumption in the
subendocardium, requiring a
higher resting flow level, as
well as the more pronounced
effects of systolic contraction
on subendocardial vasodilator
reserve.
11. Endothelium-Dependent Modulation
of Coronary Tone
• Epicardial arteries do not normally contribute
significantly to coronary vascular resistance.
arterial diameter is modulated by a wide
variety of paracrine factors that can be
released from platelets, as well as circulating
neurohormonal agonists, neural tone, and
local control through vascular shear stress.
12.
13. DETERMINANTS OF CORONARY
RESISTANCE
Flow is determined by
the segmental
resistance and
therefore
an understanding of
the resistance beds is
necessary:
3 resistance beds
R1
R2
R3
14. • Epicardial arteries R1 (>400 μm in diameter) serve a
conduit artery function, with diameter primarily regulated
by shear stress, and contribute little pressure drop (<5%)
over a wide range of coronary flow.
• Coronary resistance vessels R2 can be divided into
• resistance arteries (100 to 400 μm), which regulate their
tone in response to local shear stress and luminal pressure
changes (myogenic response), and
• arterioles (<100 μm), which are sensitive to changes in
local tissue metabolism and directly control perfusion of
the low resistance coronary capillary bed.
• Capillary density R3 of the myocardium averages
3500/mm2,
resulting in an average intercapillary distance of 17 μ m,
and is greater in the subendocardium than the
subepicardium. Fixed resistance only 20%.Increased in HF
15. R1 – Conduit artery
resistance , insignificant
normally
R2 – Precapillary
arterioles and small
arteries (under metabolic
and autoregulatory
adustment)
R3 – Time varying
compressive resistance
more in subendocardial
area
In absence of stenosis –
R2>R3>R1
In presence of stenosis
or pharmacological
vasodilatation –
R1>R3>R2
16. Intraluminal Physical Forces Regulating Coronary Resistance.
Myogenic control
ability of vascular smooth
muscle to oppose changes
in coronary arterial
diameter.3 Thus vessels
relax when distending
pressure is decreased and
constrict when distending
pressure is elevated
L type calcium channels
Occurs in arterioles
<100um
Flow mediated
shear stress
related
Coronary small arteries
and arterioles also
regulate their diameter
in response to changes
in local shear stress.
Flow-induced dilation
in isolated coronary
arterioles is
endothelium-
dependent and
mediated by NO,
Metabolic
control
By ATP senstive
pottasium
channels
BY Adenosine, PH,
Hypoxia
17. Small distal
arterioles
immediately before
the capillaries are
sensitive to tissue
metabolites.
Upstream intermediate
arterioles are pressure-
sensitive, with
myogenic mechanisms
predominating.
Small resistance
arteries are removed
from the metabolic
milieu and primarily
adjust local tone in
response to shear
stress and flow..
18.
19. PHYSIOLOGICAL ASSESSMENT OF
CORONARY ARTERY STENOSES
• STENOSES PRESSURE FLOW RELATIONSHIP
• The relationship between pressure drop across a
stenosis and coronary flow for stenoses between
30% and 90% diameter reduction can be described
using the Bernoulli principle.
• The total pressure drop across a stenosis is governed
by three hydrodynamic factors—
• viscous losses,
• separation losses, and
• turbulence
20. - The single most important
determinant of stenosis resistance
for any given level of flow is the
minimum lesional cross-sectional
area within the stenosis.
- Resistance is inversely
proportional to the square of the
cross-sectional area.
- Separation losses determine the curvilinearity
or steepness of the stenosis pressure-flow
relationship.
- Stenosis length and changes in cross sectional
area distal to the stenosis are relatively minor
determinants.
21. Very little increase in
epicardial conduit artery
resistance (R1) develops
until stenosis severity
reaches a 50% diameter
reduction.
As a result, there is no
significant pressure drop
across a stenosis or
stenosis-related alteration
in maximal myocardial
perfusion until stenosis
severity exceeds a 50%
diameter reduction.
22. • As stenosis severity increases further, the curvilinear
coronary pressure-flow relationship steepens and increases
in stenosis resistance are accompanied by concomitant
increases in the pressure drop (ΔP) across the stenosis.
• This reduces distal coronary pressure, the major
determinant of perfusion to the microcirculation, and
maximum vasodilated flow decreases.
• A critical stenosis, one in which subendocardial flow
reserve is completely exhausted at rest, usually develops
when stenosis severity exceeds 90%.
24. • TFC – is number of cine frames from
introduction of contrast in coronary artery to
predetermined distal landmark at
30frames/sec.
• Distal landmarks – For LAD, distal bifurcation
of LAD, For LCX is distal bifurcation of branch
segment with longest total distance, For RCA it
is first branch of poster lateral artery
25.
26. • TFC can be corrected to CTFC by normalizing for
length of LAD in comparison to two other major
arteries. Thus CTFC accounts for the distance
contrast has to travel in LAD relative to other
arteries. (average length LAD 14.7cm, lcx 9.3cm
and RCA 9.8cm)
• CTFC for LAD – TFC/1.7
• For LAD TFC 36+/-3, CTFC 21+/- 1.5
• FOR LCX TFC 22+/-4, FOR RCA TFC is 20+/-3
• Prolonged TFC – Microvascular dysfunction
Gibson CM et al TIMI FRAME COUNT
CIRCULATION 1996
27. • TIMI BLUSH score – sucessful reperfusion in ACS
is defined as TIMI 3 flow, However TIMI 3 flow
does not allways result in effective myocardial
reperfusion.
• MBG – measure of reperfusion at capillary level.
• MBG grade 3 indicates normal blush or contrast
density comparable with angiography of
contralateral or ipsilateral non infarct related
coronary arteries.
• Length of angiography run needs to be extended
• For LAD – left lateral view and for RCA RAO view
28. LIMITATIONS OF CORONARY ANGIOGRAPHY
• Interpretation is highly subjective
• CAG provides a 2–dimentional view of a 3-dimensional lumen.
• Severity of a stenotic lesion is reported in comparison to a normal
reference segment . This is particularly fallacious in case of diffuse
disease.
• CAG is a lumenography & does not provide information regarding
vessel wall & extent of positive or negative remodeling.
• An ecentric stenosis has varying appearance of severity in different
views. The length, size and severity of a lesion & its relationship
with the vessel wall can affect the coronary flow.
• Several artifacts contribute to the disparity in interpretation like
vessel foreshortening, overlapping vessels, calcification & contrast
streaming.
29. Concept of Maximal Perfusion and
Coronary Reserve
• GOULD originally proposed the concept of
coronary reserve.
• There are currently three major indices used
to quantify coronary flow reserve—
• absolute,
• relative, and
• fractional
32. CORONARY HYPEREMIA FOR STENOSIS ASSESMENT
• At maximal hyperemia, auto regulation is abolished and
microvascular resistance remains fixed and minimal.
• At this point CBF is closely dependent on coronary arterial
pressure.
• Reactive hyperemia by transient occlusion, IC papaverine, IC
dipyridamole, ATP, Nitroprusside, Adenosine is DOC
• Jermias et al compared IC (15-20ug for RCA/18-24ug for LAD) with
IV adenosine (140ug/kg/min) found linear relationship
• Sustained Hyperemia, weight based dosing and lack of operator
interaction Makes IV route preferable than IC
GROSSMAN and BAIMS
33.
34. ABSOLUTE FLOW RESERVE
It is expressed as the ratio of maximally vasodilated flow to the
corresponding resting flow value in a specific region of the heart and
quantifies the ability of flow to increase above the resting value
Normal AFR ~ 4-5
- Clinically significant impairment if <2
- AFR incorporates functional importance of a stenosis + microcirculatory
dysfunction
Absolute flow reserve is altered not only by factors that affect maximal
coronary flow but also by the corresponding resting flow value.
Resting flow can vary with hemoglobin content, baseline hemodynamics, and
the resting oxygen extraction.
As a result, reductions in absolute flow reserve can arise from inappropriate
elevations in resting coronary flow and from reductions in maximal
perfusion.
35. Absolute flow reserve can be quantified using
intracoronary Doppler velocity or
thermodilution flow measurements, as well as by
quantitative approaches to image absolute tissue
perfusion based on PET
In the absence of diffuse atherosclerosis or LV
hypertrophy, absolute flow reserve in conscious
humans is similar to measurements in animals,
with vasodilated flow increasing four to five times
the value at rest.
In patients of hypercholesterolemia, diffuse
atherosclerosis, even in absence of obstructive
CAD, CFR is less
A significant limitation of absolute flow reserve
measurements is that the importance of an
epicardial stenosis cannot be dissociated from
changes caused by functional abnormalities in the
microcirculation that are common in patients
(e.g., hypertrophy, impaired endothelium-dependent
vasodilation).
37. Relative Flow Reserve
• Measured using nuclear
perfusion imaging .
• In this approach, relative
differences in regional
perfusion are assessed
during maximal
pharmacologic vasodilation
or exercise stress and
expressed as a fraction of
flow to normal regions of the
heart.
38. Limitations:
• First, conventional SPECT imaging requires a
normal reference segment within the left
ventricle for comparison.
• Because of this, relative flow reserve
measurements cannot accurately quantify
stenosis severity when diffuse abnormalities in
flow reserve related to balanced multivessel CAD
or impaired microcirculatory vasodilation are
present.
39. Fractional Flow Reserve
This technique, pioneered by PIJLS, is based on the
principle that
the distal coronary pressure measured during
vasodilation is directly proportional to maximum
vasodilated perfusion
40. Fractional flow reserve (FFR) is an indirect index determined by
measuring the driving pressure for microcirculatory flow distal to the
stenosis (distal coronary pressure minus coronary venous pressure)
relative to the coronary driving pressure available in the absence of a
stenosis (mean aortic pressure minus coronary venous pressure).
FFR model assumes that under maximum arterial vasodilation,
the resistance of the myocardium is minimal and constant across
different myocardial vascular beds, and thus blood flow to the
myocardium is proportional to the driving pressure
(myocardial perfusion pressure).
FFR can be derived separately for the myocardium, for the epicardial coronary artery,
and for the collateral supply.
An FFR of 0.9 = Only 90% of maximal CBF is able to cross the lesion
An FFR of 0.71 = 71% of maximal CBF crosses lesion
41. The FFR is simplified to Pd/Pa given the
assumption that Pv is negligible relative to Pa
44. • FFR is required in
• Moderate coronary stenosis (e.g. 50–70% angiographic severity) when
functional information is lacking.
• Serial coronary stenoses
• Intermediate left main stem disease
• Post-PCI / stent optimisation
• Side branch lesion severity
• Saphenous vein graft disease severity
• Non-culprit lesions in acute coronary syndromes
• Non-coronary indication: assessment of aortic valve stenosis severity
45. UNIQUE FEATURES OF FFR
• Normal value of 1 irrespective of the patient , artery or vascular bed. It is
independent of gender & other factors like DM & HTN
• Well defined cut-off values :
– FFR values ≤ 0.75 is invariably associated with inducible ischemia
(sensitivity 88%, specificity 100%, positive predictive value 100% &
overall accuracy 93%)
– FFR ≥0.80 is usually not associated with inducible ischemia.
– The gray zone of 0.75 to 0.80 spans over a small range of FFR values.
• Systemic haemodynamics like heart rate , blood pressure & LV
contractility do not affect the value of FFR since the value of Pd & Pa are
taken simultaneously.
• Reproducibility : FFR is reproducible since the microvasculature has the
capacity to vasodilate the same extent repeatedly.
46. Advantages of FFR
• - Independent of HR, SBP & driving
pressure.
• - A lesion specific index and
independent of status of
microcirculation
• - Independent of contribution by
collateral flow
• - Highly reproducible when compared
to AFR
• - Superior to quantitative CAG and
IVUS in physiological assessment
Limitations of FFR assessment
• Maximum hyperemia is
mandatory for assessment
• Assumptions : 1) Coronary venous
pressure is 0, 2) P-Q relationship is
linear
• FFR cut-off of 0.75 is derived from
a stable population with SVD and
• normal LV function – not
universally applicable to all
scenarios.
• “Pitfalls” of pressure
measurement need to be avoided
• Wedging of the guide catheter
(0.16mm2 ) may alter absolute
pressure measurements in critical
stenosis
• Limited data for acute MI
47. IMPACT OF MICROCIRCULATORY ABNORMALITIES ON
PHYSIOLOGIC MEASURE OF STENOSIS SEVERITY
• In absence of microvascular dysfunction – AFR,RFR and
FFR are closely reated
• Microvascular dysfunction in presence of normal
coronaries (0% stenosis) attenuates coronary flow
reserve.
• Conversely for any given stenosis, FFR measured in
presence of microvascular dysfunction will be higher
than when vasodilator response is normal
• Thus when maximum vasodilatation not achieved, FFR
will underestimate physiologic severity of stenosis.
48. • So combined measurement of FFR and CFR by
single wire are helpful in which mixed
abnormality is there.
49. APPLICATIONS OF FFR IN SPECIFIC
SUBSETS
• Intermediate lesions
• • Intermediate lesions with a FFR of ≥ 0.80 can be safely
defered.
• The DEFER study has shown that patients with single
vessel stenosis and FFR >0.75 who did not undergo PCI
had excellent outcomes.
• The risk of cardiac death or MI related to the stenosis was
< 1% per year and was not reduced with PCI.
• In contrast, patients with single-vessel stenosis and FFR
<0.75 are 5× more likely to experience cardiac death or MI
within 5 years, despite undergoing revascularization
50.
51. Conclusions :
Five-year outcome after deferral of PCI of an intermediate coronary stenosis based on
FFR 0.75 is excellent.
The risk of cardiac death or myocardial infarction related to this stenosis is <1% per year
and not decreased bystenting
56. CONCLUSIONS:
Routine measurement of FFR in patients with multivessel disease (MVD) who are
undergoing PCI with drug-eluting stents (DES) significantly improves outcomes at 1
year by reducing MACE (composite rate of death, nonfatal myocardial infarction, and
repeat revascularization
57.
58.
59.
60.
61.
62.
63. If 2 lesions in same territory then
Measure summed FFR by passing
wire distal to last lesion, if FFR >0.8,
defer stenting
If FFR <0.8, get pullback, lesion with
maximum pressure gradient should
be stented
If after stenting FFR>0.75 – no further
action
If after stenting FFR<0.75, stenting of
second lesion is also required.
Post stenting
• Nico H.J. Pijls at al showed that FFR
measured after stenting should be
>0.90 & is an independent predictor of
6 month mortality.