Definition of LVA Centerline analysis of RWMA on LV angio in 30º RAO shows hypocontractile segments moving more than 2 standard deviations out of normal range.
The heart has four valves; the other two are the mitral and the tricuspid valves. The aortic valve normally has three cusps or leaflets, although in 1–2% of the population it is found to congenitally have two leaflets
Foreign body removal during cardiac catheterizationRamachandra Barik
The removal of foreign bodies from the heart and vasculature has shifted from the domain of the radiologist and even the thoracic or vascular surgeon to the terventional cardiologist and, in turn, from the radiographic suite or operating room to the cardiac catheterization Laboratory.
Definition of LVA Centerline analysis of RWMA on LV angio in 30º RAO shows hypocontractile segments moving more than 2 standard deviations out of normal range.
The heart has four valves; the other two are the mitral and the tricuspid valves. The aortic valve normally has three cusps or leaflets, although in 1–2% of the population it is found to congenitally have two leaflets
Foreign body removal during cardiac catheterizationRamachandra Barik
The removal of foreign bodies from the heart and vasculature has shifted from the domain of the radiologist and even the thoracic or vascular surgeon to the terventional cardiologist and, in turn, from the radiographic suite or operating room to the cardiac catheterization Laboratory.
ECHOCARDIOGRAPHIC EVALUATION OF MITRAL VALVE DISEASEPraveen Nagula
MITRAL VALVE ANATOMY , M MODE FINDINGS IN MITRAL STENOSIS,EVALUATION OF THE SEVERITY OF LESION,CALCIFIC MS,CCMA,CONGENITAL LESIONS,GUIDELINES ALL IN DETAIL....
final cvs physio to reach out to the same thing with you regardingLokesh444339
Cvs received this is the same thing with you regarding the same thing with you regarding the same thing with you and your family is not able get registered
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
2. • It has been just over 100 years since Alexis Carrel first described the concept of operating
on the coronary circulation.
Over this time CABG has gone through three distinct eras :
1st Experimental period, 2nd Vein graft era, and the Current era
of mixed venous and arterial grafting.
• Alexis Carrel was one of the first surgeons to appreciate the relationship
between angina and obstructive coronary artery disease.
• The LITA was used in humans as early as 1945 by Arthur Vinberg, who implanted it directly
in the myocardium of the LV, the “Vinberg Procedure”.
• Robert H. Goetz performed the first successful clinical
CABG on May 2, 1960 using a non-suture technique
to connect the RITA to the coronary artery.
Alexis Carrel
3. • Vasilii Kolesov, who is believed to have been the first to perform a sutured
anastomosis of an internal mammary artery to the left anterior descending artery
25 February 1964.
• Michael DeBakey, who led his team to perform a saphenous vein aorto-coronary
bypass with a continuous suture technique on 23 November 1964.
• Rene Favaloro, who was the first to systematically perform CABG with reproducible
results and is considered to be “the father of bypass surgery”.
4. Arterial Conduit :
Autologous
• Right and left Internal thoracic artery
• Radial artery
• Inferior epigastric artery
• Splenic artery
• Gastroduodenal artery
• Left gastric artery
• Intercostal artery
Non- Autologous
• Bovine Internal thoracic artery.
6. Histology of Blood vessel :
Three coats or Tunica, except in capillaries.
1. Tunica Intima
The internal elastic lamina contains fenestrations.
That allows passage in for perfusion & migration of cells.
7. 2. Tunica Media
Dense connective tissue layer.
Thicker in arteries than in vein.
Smooth muscle are more in arteries.
The external elastic lamina is thinner and
with few fenestrations.
3. Tunica Adventitia
The connective tissue continues and fueses
with the stroma of the organ system.
It may contains vasa vasorum.
8. The tunica intima and adventitia are longitudinally arranged where as the media is
circular.
The endothelium is lined by squamous cells, and secrets chemical mediators for :-
• Diapedesis (leukocytes)
• Blood coagulation (thromboplastin & VW factor, prostaglandins)
• Vascular tone (nitric oxide, EDRF).
Nourishment of blood vessel :
Small & medium blood vessel have their nutrient & gaseous exchange by direct
diffusion from the lumen. A wall thickness up to 350 microns can be easily perfused
through diffusion.
In larger vessel the inner part, up to middle of T. media is by simple diffusion but the
outer layers are by specialized arterioles/venules called vasa vesorum.
10. Internal Thoracic / Mammary Artery (ITA/IMA) :
Origin : From the inferior aspect of the first part
of subclavian artery opposite the thyrocervical trunk,
about 2-3 cm above the sterno-clavicular jn.
Course:
• Above the first costal cartilage, it runs downwards,
forward and medially behind the SC jn.
• Related posterior to subclavian v & phrenic N.
• Below the first costal cartilage, it runs down along
the lateral to edge of sternum.
• Its termination in the 6th ICS by dividing into the
superior epigastric and musculophrenic arteries.
11. Relationships
Anteriorly – Upper six costal cartilages and the internal intercostal muscles of the
spaces.
Posteriorly – Sternocostalis muscle.
12. Branches:
1. Pericardio-phrenic artery – arises at the root of neck and accompanies the phrenic
nerve.
Supplies pericardium and pleura
2. Mediastinal arteries – irregular branches supply the thymus & mediastinal soft
tissue.
3. Two anterior intercostal arteries per space in upper six ICS.
4. Perforating branches to the anterior chest wall.
In females 2,3,4 perforators supply the breast.
5. Superior epigastric artery enters the rectus sheath at the 7th cartilage.
6. Musculophrenic artery runs down and laterally behind the costal cartilages and
gives anterior intercostal arteries.
13. Histology of the ITA :
1. Lined with typical arterial endothelium.
2. Internal elastic lamina has fewer and smaller fenestrations.
3. The media contains fewer smooth muscle cells and 5-9 elastic lamellae.
4. The proximal and distal end 10 to 20 % contains fewer elastic lamellae, and
usually none are distal to the bifurcation.
5. The adventitia contains dense collagen fibers and loose alveolar tissue that
contains adequate vasa vasorum.
6. Wall thickness is about 200 μm, which is well under the 350 μm that can be
nourished by diffusion from the lumen.
14. Features of IMA suitable as coronary conduit :
1. It is a artery of medium-small caliber, with predominant elastic component,
especially in its
proximal part.
2. It has preserved network of vasa vasorum, residual periadventitial connective
tissue, and
nervous fibers without plexus.
This outlines ITA as a “living” conduit even after its skeletonization.
3. There is a weak possibility of spasms in response to adrenergic stimuli.
But, the endothelial integrity secures the reflex release of nitric oxide and other
vascular
relaxing factors.
4. The prevalent elastic fibers explains its good compliance and increased cross-
sectional
15. 5. As an arterial conduit, it is used to arterial pressures therefore lesser intimal
hyperplasia
is seen in longer duration.
6. The anatomical location is suitable for coronary grafting.
7. Suitable diameter – 3.5 mm matches coronary.
8. The intact endothelium produces EDRF (NO) and prostacyclin thus resistant to
spasm and
blockage.
9. Interestingly, it is rarely affected by atherosclerosis.
It has been observed that the degenerative process of elastolysis causes
fragmentation in fibers of the tunica media and internal elastic membrane.
But here, this is followed generation of muscle-like cells which is not of vascular
origin. Thus there is no migration on vascular smooth muscle cells through the
lamina.
16. Role NO in vascular hemodynamics :
NO is produced by the enzyme nitric oxide synthetase and it relaxes the smooth
muscle
tissue by promoting the synthesis of cGMP
.
The ITA endothelium releases more prostaglandin I-2 (prostacyclin)
and shows greater NO mediated vasodilation than veins.
Extraluminal NO causes relaxation of vascular smooth muscle.
Intraluminal NO inhibits platelet aggregation & adhesion.
Downstream travel of NO from the ITA can cause coronary
vasodilation.
Because NO inhibits mitogenesis and smooth muscle proliferation,
17. In ITA Histamine is a potent stimulus for NO release.
Serotonin-induced vasoconstriction is inhibited by NO.
The serotonin from platelets, mast cells and damaged endothelium are implicated in
acute coronary spasm and may contribute to venous graft spasm but are unlikely to
cause ITA spasm.
Harvesting Techniques :
1. Intra thoracic 2. Extra thoracic.
1. Pedicle graft : There is an entire pedicle of veins, muscle and fascia.
Conventional technique, simple and feasible for daily practice.
However, the wide-pedicled graft with surrounding muscle and
fascia has
limited arterial length, especially in case of multiple anastomoses.
18. 2. Skeletonization : Only the artery is isolated.
Improve conduit flow with larger vessel diameter, has increased
length,
and can reduce risk of deep sternal infection specially in
diabetic pts.
However, the skeletonization can cause injury to the artery,
require
more time and skill.
3. Semi skeletonized: With just accompanying veins.
Semi skeletonization provides a lean-
pedicled graft with max length,
without lengthening the operative time.
19. Perioperative spasm : IMAs with poor perioperative flow rates are more likely to
occlude.
An adequately dilated IMA graft facilitates proper placement of
sutures.
To relieve the spasm vasodilating substances are applied to the outside of the pedicle
or can be injected intra-luminally with or without hydrostatic dilation.
Hydrostatic dilation with papaverine and saline provides good dilation but carries
risk of
mechanical damage to the media and intima caused by cannulation and
overstretching and chemical damage (acidity).
Blood with dissolved papaverine was less acidic and thus preferred.
20. Grafting strategy :
Unilateral :
A. LIMA to LAD - Well accepted, gold standard.
B. LIMA to circumflex (marginal branches).
C. RIMA to RCA, RIMA to LAD.
Bilateral :
1. RIMA to LAD + LIMA to LCx marginal branches.
2. LIMA to LAD + RIMA through transverse sinus LCx marginal br.
3. Composite Y graft with free RIMA to LIMA.
With LIMA to LAD and RIMA to Cx marginal branches.
1. 2.
3.
21. Patency :
LITA to LAD = 92 to 97 percent at end of 1st year.
88 to 96 percent at 5 years
88 to 93 percent at 10 years.
RITA patency is less by 5 to 10 percent
(but if only RITA to LAD is considered, patency rates are comparable.)
The failure rate for ITA grafts is 0.5 to 1.0 percent per year between 1st yr and 10th yr.
Unlike saphenous vein grafts, ITA grafts rarely develop arteriosclerosis.
Less than 4% of ITA have clinical evidence of arteriosclerosis, and less than 1% have
significant luminal narrowing by the end of 1st year.
(Data from : Long-Term Results of Internal Thoracic 12 Artery Grafting J.F. Sabik III, F.D. Loop, Arterial Grafting for Coronary Artery Bypass
Surgery, https://link.springer.com/)
22. Factors influencing conduit patency
a) Intimal fracturing and thrombosis.
b) Profound spasm with secondary thrombosis.
c) Faulty anastomotic technique.
d) Severe calcific coronary disease.
e) Competitive coronary flow causing thrombosis.
24. Radial Artery :
Alain Carpentier first used the RA in 1971.
However, within 2 yrs there were reports of early failure &
significant intimal hyperplasia, which resulted in almost
complete abandonment of its use as a graft.
Techniques of early RA skeletonization combined with the use of mechanical
dilatation resulted in vessel trauma and spasm and subsequent early graft failure.
Christopher Acar in 1992, used a more refined “no-touch” method of harvesting &
used pharmacological vasodilatation.
This better understanding of graft physiology and protection of the endothelium led to
100% RA patency on early postoperative angiography.
A number of RCT that have compared the RA to SVG and free RITA as the graft for non-LAD targets
showed the RA to have superior patency on 5-year angiographic follow-up.
(RAPS (Radial Artery Patency Study), Radial Artery Versus Saphenous Vein Patency – RSVP trails)
25. Origin and course:
The radial & ulnar arteries originate as a bifurcation
of the axillary A in the cubital fossa.
It runs along the lateral aspect of the forearm between
the brachioradialis and flexor carpi radialis muscles.
Proximal to the wrist, it splits into
the superficial & deep palmar branch
forming an anastomosis with the distal
branches of the ulnar artery in the hand
(Palmer Arches).
26. Histology of RA :
It is a medium sized muscular artery.
With relatively more fenestrations in the
elastic laminas.
T. Media has more smooth muscle cells
than elastic fibres.
T. adventitia has more fatty-fibrous tissue
and less concentration of vasa vasorum.
27. Features of RA suitable as coronary conduit :
PROS :
• It has an adequate length to reach any coronary vessel.
• Proper diameter (2–3 mm without size mismatch to the coronary arteries).
• Robust structure, and relative resistance to kinking.
• Has higher patency rates compared to SVGs.
• Superficial anatomical location and easy to manipulate surgically.
• Can be harvested with the IMA and SV at the same time.
• Is less risky for sternal wound infection and mediastinitis.
28. CONS :
• The tendency for vasospasm is its most important negative characteristic.
• Elastic laminae have multiple fenestrations. This is the reason why the RA presents
a
vulnerability to atherosclerosis.
• Diabetes mellitus and renal dysfunction aggravate vascular wall morbidity leading
to intimal hyperplasia in RA grafts.
• It produced less NO than the ITAs.
• Intense reactivity to endothelin I, angiotensin II, nor-epinephrine, serotonin etc,
released after any endothelial damage or platelet aggregation.
This possibly also explain its spastic character.
• Flow competition phenomenon with mildly stenotic native coronary arteries is
common in RA grafts (string sign).
29. RA harvesting technique :
RA harvest can be: 1. Open or Endoscopic.
2. Pedicled or Skeletonized.
Conventional harvesting is with the accompanying veins and fat, minimal handling,
limited use of electrocautery. Avoiding probing or hydrostatic dilation.
Modified harvesting technique using ultrasonic scalpel / harmonic scalpel , can cut
and coagulate causing minimal thermal injury of the graft.
Endoscopic harvesting technique
A 3 cm incision on the wrist crease, parallel to the RA.
7 mm scope, the harvesting cannula and bipolar scissors
are used.
Vasoview 7 System
30. Skeletonization of the RA is superior to the pedicled technique in terms of patency
rates.
However, there are also disadvantages, such as irreversible injury to the RA or
spasms.
Management of RA conduit spasm :
The gold standard to prevent RA spasm is systemic administration of systemic
diltiazem,
in combination with topical papaverine.
The intraluminal injection of warm arterial blood and papaverine is also favored.
Other topical RA antispasmodic in clinical use are calcium channel blockers,
verapamil with nitroglycerin (VG solution), and phenoxybenzamine.
Avoidance of cold saline or ice slush in the pericardium is also significant to prevent
spasm.
31. Preoperative exclusion criteria for RA harvesting :
Allen test is the most widely used clinical test for preoperative evaluation of
sufficient ulnar collateral circulation to the hand.
A Barbeau test using a pulse oximeter on (1st or 2nd finger), contributes to assure an
intact palmar arch observing the pulse and saturation.
Doppler study not only allows for the evaluation of the ulnar collateral circulation to
the hand, but also for the preoperative assessment of RA.
33. Patency & Comparison :
RA conduits appear to be superior to SV grafts in terms of early and late mortality
and morbidity, and also in long term survival and freedom from cardiac events.
Graft patency
Short term = 96–100%,
Mid term= 94–97%
Long term = 84–96%
Radial Artery vs. Saphenous Vein Graft Patency (RSVP) trial proved that the graft patency of the RA to the circumflex coronary artery at 5 years
(98.3%) was better than that of the SV (86.4%) and graft narrowing happened in 10% and 23% of patent RA and SV grafts, respectively.
(Kaplan-Meier estimates of event-free survival and over all survival of RA vs. SV patients
Results of a randomized trial. Eur J Cardiothorac Surg 2008;34:113-7)
34. Complications after RA harvesting :
Most common are bleeding, hematomas and wound infection.
Sensory nerve injuries, causing sensory abnormality and numbness in 3–10% of
patients.
Motor impairments are usually a early finding.
Less common is hand ischemia.
35. Right Gastroepiploic Artery :
The GEA is the largest & terminal branch of the gastroduodenal A.
It runs along the posterior surface the prox duodenum, anterior of
the pancreas head, then along the greater curvature of the stomach.
Bailey et al in late 1960s used RGA for indirect myocardial
revascularization for the posterior or inferior wall of the heart.
Direct anastomosis of GEA to the RCA was attempted by Sterling Edwards in early
1970s.
Histologically it is very similar to ITA.
This artery undergoes less arteriosclerosis and demonstrates physiological
adaptability as seen in ITA.
36. GEA is more strongly contracted by KCl, serotonin, and norepinephrine than the ITA,
therefore it is important to prevent spasm of the GEA provoked by platelet
aggregators, adrenergic stimulation, or depolarizing agents.
GEA harvesting technique :
Median sternotomy incision is extended to the xiphoid & umbilicus.
After harvesting the pedicle is raised up through the hole in the
diaphragm passing the liver and the stomach anteriorly, and the end
of the pedicle is fixed to the anterior edge of the diaphragm.
Grafting strategy :
As a in situ graft to RCA or
as free graft as per requirement.
37. Patency
Perrault et al with 51 right gastroepiploic in situ grafts with a patency rate of 90% in
prior to hospital discharge.
At the end of 1st year patency rate of 80% .
With improvement in technique Suma et al showed a10 year patency 87%.
38. Inferior Epigastric Artery :
The inferior epigastric artery is a branch of the FA.
Passes supero-medially from inguinal canal towards the midline.
In 1988, Puig et al. reported the use of the IEA as a bypass conduit.
PROS :
Its superficial course makes harvest easy.
Near perfect match with the branches of RCA or LCx.
Resistance to arteriosclerosis. Its internal elastic lamina has minimal fenstrations.
CONS :
Proximal anastomosis is difficult, wall thickness mismatch. So, composite graft is preferred.
The most frequent complication is an abdominal or retroperitoneal hematoma
Although rare, cases of skin and rectus muscle necrosis are reported.
Its use is favoured on unavailability or unsuitability of
SVG or IMA or RA or a desire of preserving one IMA for the future.
40. Course :
Formed by the dorsal venous arch of the foot, and the dorsal vein
of the great toe.
It ascends up the medial side of the leg, passing anteriorly to the
medial malleolus, and posteriorly to the medial condyle at the knee.
It receives tributaries from other small superficial veins.
The great saphenous vein terminates by draining into the
femoral vein immediately inferior to the inguinal ligament.
41. Histology of the GSV :
The wall of the saphenous vein contains a thin intima, separated from the media by a rudimentary internal
membrane.
The media consists of two distinct layers of muscle cells, outer circular with abundant collagen fibers and inner
longitudinal with few elastic fibers. The longitudinal muscle layers continues into the valve of the veins.
Prominent tunica adventitia with poor vasa vasorum.
The elastic lamina is very poor and interrupted.
42. As a conduit :
PROS :
1. Superficial and easy to harvest.
2. Less time consuming.
3. Suitable size.
4. Adequate length can be easily achieved.
5. Less scaring, quick healing and less complications.
CONS :
1. Development of Vein Graft Disease.
2. Low potential to secrete intrinsic NO & prostacyclin.
3. Not adapted to high arterial pressures.
4. Poor intra luminal perfusion, and thus skeletonized graft can be considered a “dead graft”
5. Diseased veins.
Contraindications :
Varicosities, DVT, PVD, skin disease, diabetic ulcers, recent leg trauma etc.
Diagnostic tests : Doppler, venography and mapping.
43. Harvesting Techniques :
1. Open technique - Continuous incision.
- Interrupted bridging skin incision.
2. Endoscopic.
Harvest with adequate fat pad.
Maintain a proper luminal uniformity.
Avoid hydrostatic dilation, blood is preferred.
Excessive pressure may cause intimal injury.
44. Saphenous Vein Graft Disease
Saphenous vein graft disease is composed of three discrete processes:
1. Thrombosis, 2. Intimal hyperplasia, 2. Atherosclerosis.
1. Thrombosis
About 3%-12% within the 1st month.
Combination of alterations in the vessel wall, blood coagulability, and flow dynamics.
The harvesting of venous conduits is associated with focal endothelial disruption.
Loss of the endothelial monolayer results in the accumulation of fibrin on the
surface, the adherence of platelets and neutrophils.
It also activates the extrinsic coagulation cascade by tissue factor that is
expressed in the exposed sub-endothelium.
Inherent anti-thrombotic properties of veins are comparatively weak.
45. 2. Intimal Hyperplasia
Intimal hyperplasia, defined as the accumulation of smooth muscle cells and extracellular
matrix in the intimal compartment.
Major disease process b/w 1month to1 yr, which may reduce the lumen by 25% & above.
Initially, medial smooth muscle cells proliferate in response to growth factors and cytokines
from platelets, endothelial cells and macrophages.
This followed by migration of smooth muscle cells into the intima.
Later synthesis and deposition of extracellular leads to a progressive increase in intimal
fibrosis.
Explained by transient ischemia to the veins during explanation and reperfusion after grafting.
Loss of the vasa vasorum blood supply, on which veins are relatively more dependent than
arteries, may also promote a continuing cycle of ischemia and fibrosis
46. 3. Atherosclerosis
Dominant process beyond the first year after bypass surgery.
Angiographic studies indicate that among patients who had unstable angina, the culprit
lesion in
70% to 85% of cases is an atherosclerotic vein graft stenosis with thrombosis.
Chronic endothelial cell injury and dysfunction lead to rapidly progressive nature of the
atherosclerotic.
Vein graft atheroma has more foam cells and inflammatory cells, including multinucleate
giant cells suggestive of immune-mediated atherosclerosis.
Morphologically, vein graft atherosclerosis tends to be diffuse, concentric, and
friable with a poorly developed or absent fibrous cap and little evidence of calcification,
promoting plaque rupture and thrombosis.
47. Risk factors for vein grafts disease :
a) Smoking
b) Hypertension
c) Diabetes
d) Dyslipidemia (T triglyceride and cholesterol)
e) Female gender
48. Recent Advances :
The e SVS mesh is a flexible extravascular nickel-titanium mesh designed to
reinforce SVGs exposed to the higher arterial pressure in CABG.
It give some physiological attributes of an artery to the SV grafts, thus claimed to
prevent reactive intimal hyperplasia.
Although long-term patency studies are not yet available, first safety reports and
short-term results have been recently published are encouraging.
49. Alternative conduits for CABG
The ideal graft characteristics :- Non-thrombogenic, Sufficient mechanical
strength, Similar compliance to native vessels, Spontaneous
endothelialisation, Resistance to intimal hyperplasia and Compatibility with
the host tissue.
PTFE : Inert fluorocarbon polymer, non-biodegradable, electronegative luminal
surface that is anti-thrombotic. Widely used in lower-limb bypass grafts (7–9 mm)
with excellent results.
In CABG, these grafts are found to be rigid compared with the elastic host artery.
This poor mechanical compliance and the lack of endothelial cells (ECs) lining the
lumen are major factors contributing to their poor patency.
Dacron : Polyester of multiple filaments either woven or knitted into vascular grafts.
50. Attempts to improve synthetic grafts have included embedding them with anti-
thrombotic drugs like heparin, hirudin, tissue factor pathway inhibitor, non-
thrombogenic phospholipids.
Others : Cryopreserved allograft veins, Autologous endothelialized vein allograft,
Synthetic biomaterials and polyurethanes & tissue engineered grafts.
Currently only considèred when traditional autologous conduits are unavailable or
unsuitable.
In the future, the search for an ideal coronary bypass conduit "off the shelf” will
continue
to evolve.