This document discusses Doppler ultrasound evaluation of arteriovenous (A-V) access for hemodialysis. It begins with an overview of normal Doppler ultrasound findings of the upper extremity arteries and veins. It then covers preoperative ultrasound vascular mapping to determine suitable sites for A-V access creation. The document reviews the different types of A-V accesses used for hemodialysis and the normal Doppler ultrasound findings of functioning A-V accesses. It also discusses routine surveillance of asymptomatic patients and complications that can be identified with Doppler ultrasound of A-V accesses.
Role of medical imaging in management of arteriovenous fistula Dr. Muhammad B...Dr. Muhammad Bin Zulfiqar
This presentation is very helpful for vascular sergeons, interventional radiologists and sonographers that how to map Vasculature before construction of AV fistula for hemodialysis, how to check its patency, how to check its proper functioning ,to comment on its failure and decide when to reintervene.
Role of medical imaging in management of arteriovenous fistula Dr. Muhammad B...Dr. Muhammad Bin Zulfiqar
This presentation is very helpful for vascular sergeons, interventional radiologists and sonographers that how to map Vasculature before construction of AV fistula for hemodialysis, how to check its patency, how to check its proper functioning ,to comment on its failure and decide when to reintervene.
Doppler ultrasound of visceral arteriesSamir Haffar
Doppler ultrasound of different diseases of visceral arteries including arterial stenosis and occlusion, arterial aneurysm, artrial pseudoaneurysm, arterio-venous fistula, artrial dissection, and abdominal vascular compression syndromes
Description of various ultrasound features of benign and suspicious thyroid nodules with multiple ultrasound systems for risk stratification of malignancy.
Doppler ultrasound of visceral arteriesSamir Haffar
Doppler ultrasound of different diseases of visceral arteries including arterial stenosis and occlusion, arterial aneurysm, artrial pseudoaneurysm, arterio-venous fistula, artrial dissection, and abdominal vascular compression syndromes
Description of various ultrasound features of benign and suspicious thyroid nodules with multiple ultrasound systems for risk stratification of malignancy.
se prezinta rolul ultrasonografiei Doppler in evaluarea patului vascular arterio-venos la pacientii cu indicatie de dializa, monitorizarea fistulei arterio-venoase si a eventualelor complicatii
By: Joseph Zygmunt, Jr., RVT, RPhS
Visit VeinGlobal at http://www.veinglobal.com/ for more presentations and videos on this topic, or for more information on venous disease news, education and research.
Detecting Deep Venous Disease with Duplex UltrasoundVein Global
By: Joseph Zygmunt, Jr., RVT, RPhS
Visit VeinGlobal at http://www.veinglobal.com/ for more presentations and videos on this topic, or for more information on venous disease news, education and research.
This presentation will be very helpful for interventional radiologist, vascualr sergeons and sonographers. We will discuss the basic concept of varicosities and then step by step their thermal ablation under US guiadance.
Although large efforts are spent for creating fistula as the primary access, use of Hemodialysis Vascular catheters are still the major access on the first Hemodialysis session and after 4 month whether we would like it or not.
"USRDS 2013"
This research study was carried out to see the effect of
atherosclerotic changes inside femoral arteries with the help of
diagnostic Ultrasound. Atherosclerosis in femoral arteries is
meant by any kind of damage to internal thin cell lining of
arterial walls of femoral arteries called as endothelium, which
may be due to consistent or rapid increase in blood pressure or
high level of fat deposition. To see the effect of atherosclerotic
changes in the femoral arteries of some cases, the method of
finding a change along x-axis and y-axis in the structure of
triphasic type of ultrasound image waveform was used. The
change was found to be like the production of biphasic type of
ultrasound image with prolonged portion of diastole and small
peak of systole. In case of monophasic type only low peak systole
occurred with no portion of diastole. Five cases were taken for
study. All these cases had a history of high blood pressure and
use of unbalanced diet in their normal routine. It was concluded
that formation of prolonged diastole along x-axis with low peak
of systole along y-axis in biphasic type of ultrasound image, and
formation of low peak systole along y-axis without any
component along x-axis in monophasic type of ultrasound image,
both are good indicator of atherosclerotic changes in the femoral
arteries.
Description of different ultrasound features of carpal tunnel syndrome before and after carpal tunnel release including Doppler imaging and elastography
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
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.
Title: Sense of Smell
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 primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
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
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
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.
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.
The POPPY STUDY (Preconception to post-partum cardiovascular function in prim...
Doppler ultrasound of A-V access for hemodialysis
1. Doppler US of A-V access for hemodialysis
Samir Haffar M.D.
Department of Internal Medicine
Al-Mouassat University Hospital – Damascus – Syria
2. Doppler US of A-V access for hemodialysis
Normal Doppler US of upper extremity
Preoperative US vascular mapping
Type of A-V access for hemodialysis
Normal Doppler US of A-V access for hemodialysis
Routine surveillance in asymptomatic patients
Complications of A-V access for hemodialysis
Conclusion
3. Doppler US of A-V access for hemodialysis
Normal Doppler US of upper extremity
Preoperative US vascular mapping
Type of A-V access for hemodialysis
Normal Doppler US of A-V access for hemodialysis
Routine surveillance in asymptomatic patients
Complications of A-V access for hemodialysis
Conclusion
4. Anatomy of aortic arch & subclavian artery
Right SCA originates from innominate (brachiocephalic) artery
Left SCA originates directly from aortic arch
SCA has several branches: VA & mammary (internal thoracic) artery
Thrush A et al. Peripheral vascular ultrasound. Elsevier Churchill Livingstone, 2nd edition, 2005.
5. Arterial anatomy of upper
extremity
Thrush A et al. Peripheral vascular ultrasound. Elsevier Churchill Livingstone, 2nd edition, 2005.
LSA Common origin with CCA from A
BA High bifurcation of brachial artery
RA High origin from axillary artery
UA High origin from axillary artery
Anatomical variations
6. Normal brachial artery
Deklunder G et al. EMC-Radiologie 2004 ; 1 : 632 – 646.
Diameter from intima to intima
Perpendicular to arterial wall
Sagittal US scan Sagittal color Doppler
Homogenous velocities
Good visualisation of arterial bords
7. Normal duplex US of peripheral arteries
High resistance flow
Normal brachial arteryTriphasic flow
8. Venous anatomy of upper extremity
Deklunder G et al. EMC-Radiologie 2004 ; 1 : 632 – 646.
Superficial system
Basilic vein Drains medial side of upper limb
Penetrates fascia in lower arm to join brachial vein
Cephalic vein Drains lateral side of upper limb
Join axillary vein in infraclavicular region
9. Normal venous flow
Spontaneity Spontaneous flow without augmentation
Phasicity Flow changes with respiration
Compression Transverse plane
Augmentation Compression distal to site of examination
Patency below site of examination
Valsalva Deep breath, strain while holding breath
Patency above site of examination
10. Vein compressibility
Kerr SF et al. Clin Radiol 2010 ; 65 : 744 – 749.
Compression
Regular thin wall
Diameter: 5.2 mm
Basilic vein
Vein fully compressed
Basilic vein
11. Color & pulsed Doppler of cephalic vein
Mihmanli I et al. J Ultrasound Med 2001 ; 20 : 217 – 222.
Normal lumen blush
Normal respiratory phasicity
12. Doppler US of A-V access for hemodialysis
Normal Doppler US of upper extremity
Preoperative US vascular mapping
Type of A-V access for hemodialysis
Normal Doppler US of A-V access for hemodialysis
Routine surveillance in asymptomatic patients
Complications of A-V access for hemodialysis
Conclusion
13. Doppler US criteria for good outcome
Evaluation of nondominant arm first
• Peripheral arteries Diameter at least 1.6 mm
Hyperemic response
Patent palmar arch (US Allen test)
• Peripheral veins AVF: ≥ 2 mm without tourniquet
≥ 2.5 mm with tourniquet
Graft: at least 4 mm with tourniquet
• Central veins Respiratory phasicity
“indirect assessment” Transmitted cardiac pulsatility
Valsalva (flow drops to baseline)
Silva MB et al. J Vasc Surg 1998 ; 27 : 302 – 308.
Robbin ML et al. Radiology 2000 ; 217 : 83 – 88.
14. Measurement of artery diameter
Ferring M et al. Nephrol Dial Transplant 2008 ; 23 : 1809 – 1815.
Radial artery (M mode)
Point of artery insonated over time
Diameter at peak systole: 2.1 mm
Diameter in diastole: 2 mm
From intima to intima
Perpendicular to arterial wall
Diameter: 2.2 mm
Radial artery (B mode)
Blooming effect
15. Arterial hyperemic response
Useful to predict risk of arterial steal
Wiese P et al. Nephrol Dial Transplant 2004 ; 19 : 1956 – 1963.
Clenched fist (3 min) : high-resistance flow (triphasic)
Released fist : low-resistance flow (monophasic) & RI < 0.70
Failure of such response regarded as CI to AVF
17. Color Doppler of the palmar arch
Reversed flow
Flow via ulnar artery
Occlusion of radial artery
while imaging arch
Color Doppler
of palmar artery
Mozersky DJ et al. Am J Surg. 1973 ; 126 : 810 – 812.
Levitov A et. Critical care ultrasonography. McGraw-Hill Medical, NY, USA, 2009.
US may may improve accuracy of Allen’s test
First reported in 1973
18. Radial artery at wrist
Segmental occlusive lesions
Calcified wall with marked shadowing
Parmley MC et al. Am J Surg 2002 ; 184 : 568 – 572.
20. Cephalic vein wall
Marked wall irregularity
Wall thickening especially on posterior side
Mihmanli I et al. J Ultrasound Med 2001 ; 20 : 217 – 222.
21. Robbin ML et al. Radiology 2000 ; 217 : 83 – 88.
Normal caliber of SCV
50% stenosis of BCV
Corresponding venogram
Abnormal respiratory phasicity
No decrease to baseline with inspiration
Doppler US of patent SCV
Central vein stenosis
Paget Schroetter syndrome
22. Central vein stenosis
Paget Schroetter syndrome
Robbin ML et al. Radiology 2000 ; 217 : 83 – 88.
Doppler US of patent SCV
Abnormal respiratory phasicity
Monophasic flow
Suspicion of CV stenosis/occlusion
Corresponding venogram
Severe stenosis of BCV
at its junction with SMV
Second channel adjacent to stenosis
Recognition of central vein stenosis is CI to use of that extremity
24. Upper extremity vein mapping
Cephalic vein
Mendes RR et al. J Vasc Surg 2002 ; 36 : 460 – 3.
Eight representative measurement sites of CV:
Diameter with & without tourniquet
Depth from skin
25. Preoperative vascular mapping
Robbin ML et al. Radiology 2000 ; 217 : 83 – 88.
50-year-old man with nonpalpable cephalic vein in wrist
Scheduled to receive forearm graft
Transverse cephalic veinRadial artery
at wrist
3.7 mm
Wrist
2.8 mm
Middle forearm
2.7 mm
Antecubital area
2.8 mm
Adequate diameters for AVF placement
26. Preoperative vascular mapping
Duplex sonography of upper limb arteries & veins
performed in conjunction with clinical examination in all
patients for whom an AVF is being considered
* National Kidney Foundation’s
Kidney Disease Outcomes Quality Initiative
National Kidney Foundation. Am J Kidney Dis 2006 ; 48(Suppl. 1) : S1 – S322.
Recommendations of NKF-KDOQI*
27. Doppler US of A-V access for hemodialysis
Normal Doppler US of upper extremity
Preoperative US vascular mapping
Type of A-V access for hemodialysis
Normal Doppler US of A-V access for hemodialysis
Routine surveillance in asymptomatic patients
Complications of A-V access for hemodialysis
Conclusion
28. Brescia-Cimino A-V fistula
Brescia MJ, Cimino JE, Appel K, et al. N Engl J Med 1966 ; 275 : 1089 – 92.
Side of artery to end of vein
At anatomical snuffbox or wrist
Surgeons who invented AVF:
Brescia, Cimino, & Appel
Most commonly used
29. Types of Arterio-Venous Fistula
Finlay DE et al. RadioGraphics 1993 ; 13 : 983 – 999.
Side of artery to side of vein
End of artery to side of vein
Side of artery to end of vein
Brescia-Cimino AVF
End of artery to end of vein
30. Types of A-V grafts (PTFE – Polyurethane )
Curr Probl Surg 2011 ; 48 : 443 – 517.
Forearm
Barachial artery to brachial vein
“Loop graft”
Upper arm
Radial artery to axillary vein
“Straight graft”
31. A-V access for hemodialysis in preferential order
Type Description
Forearm AVF Radial artery to cephalic vein
Radial artery to basilic vein
Radial artery to other suitable vein (transposition*)
AVF placement preferable to graft placement
Nondominant arm is preferred site for access placement
* Transposition AVFs placed in veins other than cephalic vein
Robbin ML et al. Radiology 2000 ; 217 : 83 – 88.
Upper arm AVF Brachial artery to cephalic vein
Brachial artery to basilic vein
Brachial artery to other suitable vein (transposition*)
Forearm graft Brachial artery & antecubital vein (loop graft)
Upper arm graft Brachial artery & high brachial or basilic vein
Thigh graft CFA to CFV
32. Distribution of AVF & graft use in Europe
& the United States
Huijbregts HJ et al. Eur J Vasc Endovasc Surg 2006 ; 31 : 284 – 287.
Following percentiles of each distribution provided for
the 10th, 25th, 50th (median), 75th, & 90th percentiles
33. Radio-cephalic fistula at wrist
MA (8 prospective & 30 retrospective studies – 4579pts)
High primary failure rate
Moderate patency rates at 1 year of follow-up
* Sidawy AN et al. J Vasc Surg 2002 ; 35 : 603 – 610.
Rooijens PP et al. Eur J Vasc Endovasc Surg 2004 ; 28 : 583 – 589.
• Primary failure rate*
Thrombosis or failure to mature at 6 weeks
15.3% (95% CI: 12.7 – 18.3%) [from 10% to 30%]
• Primary patency rate at 1 year of follow-up*
From creation until intervention to maintain or re-establish
patency, thrombosis or time of patency measurement
62.5% (95% CI: 54.0 – 70.3%)
34. Doppler US of A-V access for hemodialysis
Normal Doppler US of upper extremity
Preoperative US vascular mapping
Type of A-V access for hemodialysis
Normal Doppler US of A-V access for hemodialysis
Routine surveillance in asymptomatic patients
Complications of A-V access for hemodialysis
Conclusion
35. Doppler US of A-V access for hemodialysis
Abundant gel & minimal pressure on skin
Longitudinal & transverse scan from feeding artery to anastomosis
Longitudinal & transverse scan from draining vein as far as possible
Perivascular space: functional stenosis from abscess, hematoma, seroma
Edenberg Jan et al. Tidsskr Nor Legeforen nr. 2009 ; 129 : 1635 – 8.
36. Normal Doppler US in AVFs
• Feeding artery Monophasic flow
Large diastolic component
• Anastomosis Perivascular tissue vibration
Very turbulent flow over long stretch
• Draining vein Pulsatile flow (arterialized vein)
• Volume flow > 500 mL/min
Dilatation of feeding artery & draining vein
after several years of use
Schäberle W. Ultrasonography in vascular diagnosis.
Springer-Verlag, Berlin Heidelberg, 2nd edition, 2011.
37. Normal Doppler US in AVFs
Brachio-basilic fistula
Kerr SF et al. Clin Radiol 2010 ; 65 : 744 – 749.
Brachial artery
Monophasic flow
Large diastolic component
Brachio-basilic fistula
Arterialized vein
38. Doppler US of polyurethane graft
Three-layered material – Cannulation within 24 h
Wiese P et al. Nephrol Dial Transplant 2003 ; 18 : 1397 – 1400.
1 year follow-up
Signal from whole graft
Early post-operative
Strong reflection from graft
1 year follow-up
Signal at site of single cannulation
1 year follow-up
Signal at sites of repeat cannulation
39. Volume = Cross-sectional area . Mean velocity . 60
(mL/min) (cm2) (cm/sec)
Cross-sectional area (cm2): π d2 / 4
d: diameter
Measurement of flow volume
Hoskins P et al. Diagnostic US: physics and equipment.
Cambridge university press, Cambridge, UK. 2nd ed, 2010.
40. Place of flow volume measurement
• Arteriovenous fistula
Feeding artery Brachial artery in middle upper arm
Recommended by some authors
Within fistula Turbulent flow (spectral broadening)
Draining vein Abrupt change in diameter in older AFV
Changes in lumen shape (elliptical)
Recommended by other authors
• Graft
Investigated along the entire access
Schäberle W. Ultrasonography in vascular diagnosis.
Springer-Verlag, Berlin Heidelberg, 2nd edition, 2011.
41. Measurement of flow volume /Feeding artery
Diameter perpendicular to axis
Sample volume across width of vessel
Sample volume in same site of diameter measurement
Correct estimation of angle
TAMV: 3 – 5 cardiac cycles
Deklunder G et al. EMC-Radiologie 2004 ; 1 : 632 – 646.
42. Measurement of flow volume in feeding artery
Deklunder G et al. EMC-Radiologie 2004 ; 1 : 632 – 646.
Normal flow in distal radial artery
Flow volume (fistula open) – Flow volume (fistula closed)
Normal volume in upper limb: 100 mL/min (neglected)
Reversed flow in distal radial artery
Flow volume (proximal a) + Flow volume (distal a)
43. Sources of error in volume measurement
• Diameter Measuring accuracy (blooming effect)
Main source Assumption of circular cross-section
Variation during cardiac cycle
Variation during respiration (veins)
• Doppler angle As small as possible & < 60
Box steering & transducer shifting
• Mean velocity Setting of transmitted & received gain
Over or underestimation
Schäberle W. Ultrasonography in vascular diagnosis. Springer-Verlag, Berlin, 2nd edition, 2011.
44. Error percentage in volume measurements
& vessel diameter
Schäberle W. Ultrasonography in vascular diagnosis.
Springer-Verlag, Berlin Heidelberg, 2nd edition, 2011.
Errors ranging from 0.2 to 1.0 mm
45. Doppler phenomenon?
Doppler shift frequency (fd): ft – fr
Thrush A, Hartshorne T. Peripheral vascular ultrasound: How, why and when.
Elsevier Churchill Livingstone, London, 2nd edition, 2005.
ft
fr
∆ F = 2 F0 V Cos Ө / C
46. Angle of insonation & Doppler effect
Kim Min Ju et al. Curr Probl Diagn Radiol 2009 ; 38 : 53 – 60.
Angles between 30 to 60 usually used for Doppler acquisition
47. Error percentage in velocity measurements
& angle of insonation
Angle of insonation > 60 should not be used
49. Adjusting spectral Doppler gain
Gain setting too low
Correct gain setting
Gain setting too high
Kruskal JB et al.RadioGraphics 2004 ; 24 : 657 – 675.
50. Tips for volume flow measurement
• Avoid significant turbulence (circular flow)
• Accurate determination of vessel diameter
• Adequate insonation angle (≤ 60⁰)
• Sample volume covers entire area of vessel
• No significant diversion of blood through accessory vein
• Flow determined in feeding artery if complex vein anatomy
• Various algorithms used by manufacturers (by up to 30%)
Gelbfish GA. Tech Vasc Interventional Rad 2008 ; 11 : 156 – 166.
Slight errors in one parameter lead to erroneous numbers
51. Interpretation of fistula flow volume
A-V access for hemodialysis Flow volume (mL/min)
Normal value
Forearm fistula
Upper arm fistula
600 – 800
900 – 1200
Schäberle W. Ultrasonography in vascular diagnosis.
Springer-Verlag, Berlin Heidelberg, 2nd edition, 2011.
Mature fistula ≥ 500
High risk of occlusion
AVF
Graft
< 300
< 650
High-output cardiac failure
Adult
Children
> 3.000
> 700
52. Doppler US of A-V access for hemodialysis
Normal Doppler US of upper extremity
Type of A-V access for hemodialysis
Preoperative US vascular mapping
Normal Doppler US of A-V access for hemodialysis
Routine surveillance in asymptomatic patients
“Mature fistula”
Complications of A-V access for hemodialysis
Conclusion
53. Causes of immature fistula
Stenosis at or near the fistula
Angioplasty – surgical revision
One or more accessory veins
Ligation
Deep draining vein
Fistula surgically placed in more superficial soft tissues
Immature fistula can be converted into usable fistula
with correction of underlying problem
Singh P et al. Radiology 2008 ; 246 : 299 – 305.
54. Sonographically mature fistula
Doppler US exam 6 – 8 weeks after surgery
• AP diameter of draining vein At least 4 mm
• Distance from skin to anterior wall Less than 5 mm
• Flow volume At least 500 mL/min
Robbin ML. Radiology 2002 ; 225 : 59 – 64.
Singh P et al. Radiology 2008 ; 246 : 299 – 305.
Should meet the 3 following criteria
Criteria different from clinically mature fistula
55. Doppler US for routine surveillance
• AP diameter of draining vein in transverse scan
Usually thin wall: cursors within vein walls
• Distance from skin to anterior wall of draining vein
• Veins branching off within first 10 cm of anastomosis
AP diameter & distance from anastomosis
• Flow volume Straight segment of artery or vein
Repeat 3 – 5 times with average
Singh P et al. Radiology 2008 ; 246 : 299 – 305.
56. Mature fistula/Good diameter & depth
Anteroposterior diameter of draining vein: 6 mm
Distance from skin surface to anterior vein wall: 4.8 mm
Singh P et al. Radiology 2008 ; 246 : 299 – 305.
Transverse US of draining vein
57. Mature fistula/Good flow volume
Brachio-basilic fistula
Kerr SF et al. Clin Radiol 2010 ; 65 : 744 – 749.
Diameter: 7.9 mm
TAMV: 93.2 cm/sec over 3 cardiac cycles
Flow volume: 2.741 mL/min
58. Immature fistula/Large accessory vein
Singh P et al. Radiology 2008 ; 246 : 299 – 305.
Large accessory vein which may limit maturation of fistula
Search for all accessory veins within first 10 cm of anastomosis
Transverse US of draining vein
59. Immature fistula/Small & deep vein
Draining vein
Vein too small (3.1 mm)
Vein too deep (7.6 mm)
Singh P et al. Radiology 2008 ; 246 : 299 – 305.
60. Immature fistula/Low flow volume
Radio-cephalic fistula
Left radial artery
Flow volume : 86 mL/min
Left cephalic vein
Flow volume : 130 mL/min
Kerr SF et al. Clin Radiol 2010 ; 65 : 744 – 749.
61. Routine surveillance in asymptomatic patients
No RCTs of Doppler surveillance in this setting
Routine surveillance by combination of clinical examination,
direct flow measurement, & duplex US should be performed
When stenosis > 50% is accompanied by hemodynamic
or clinical abnormalities, angioplasty is recommended
* National Kidney Foundation’s
Kidney Disease Outcomes Quality Initiative
National Kidney Foundation. Am J Kidney Dis 2006 ; 48(Suppl. 1) : S1 – S322.
Recommendations of NKF-KDOQI*
62. Doppler US of A-V access for hemodialysis
Normal Doppler US of upper extremity
Type of A-V access for hemodialysis
Preoperative US vascular mapping
Normal Doppler US of A-V access for hemodialysis
Routine surveillance in asymptomatic patients
Complications of A-V access for hemodialysis
Conclusion
64. Mechanisms & sites of stenosis
• AVF Feeding artery Atherosclerosis (SC, axillary)
• Graft Intimal hyperlplasia (shear stress)
Anastomosis between graft & vein
Draining vein Intimal hyperplasia (valves)
Puncture-induced dissection
Proximal – distal
Anastomosis Turbulence (most common)
Central veins Catheters (SC, axillary)
Schäberle W. Ultrasonography in vascular diagnosis.
Springer-Verlag, Berlin Heidelberg, 2nd edition, 2011.
65. Venous stenosis from intimal hyperplasia
Edenberg Jan et al. Tidsskr Nor Legeforen nr. 2009 ; 129 : 1635 – 8.
Venous stenosis 3 cm from anastomosis
Power Doppler ultrasound
66. US Doppler criteria for significant stenosis
(> 50 % diameter reduction)
• Us criteria Percentage of diameter reduction
• Color criteria Pronounced aliasing at site of stenosis
• Duplex criteria PSV ratio
PSV: should not be interpreted in isolation
67. Measurement of luminal diameter reduction
Edenberg Jan et al. Tidsskr Nor Legeforen nr. 2009 ; 129 : 1635 – 8.
Wiese P et al. Nephrol Dial Transplant 2004 ; 19 : 1956 – 1963.
Residual lumen 1.1 mmOriginal lumen 5.1 mm
78 % diameter stenosis
Original lumen – Residual lumen
x 100% of diameter stenosis
Original lumen
=
68. Color criteria of significant stenosis
Pronounced aliasing at site of stenosis
Junction of basilic & axillary vein
69. Duplex criteria for significant stenosis (> 50%)
• Direct signs
Feeding artery PSV ratio ≥ 2
Anastomosis PSV ratio ≥ 3 – PSV > 400 cm/sec*
Draining vein PSV ratio ≥ 3 – PSV > 300 cm/sec*
• Indirect signs
Flow volume < 250 mL/min
Proximal High-resistance flow (RI > 0.70)
Distal Delayed systolic upstroke
* Flow volume adequate for hemodialysis
Schäberle W. Ultrasonography in vascular diagnosis. Springer-Verlag, Berlin, 2nd edition, 2011.
70. PSV ratio
Robbin ML et al. Ultrasound Clin 2006 ; 1 : 111 – 131.
Proximal: 2 cm proximal to stenosis
Stenosis: same Doppler angle if possible
72. Proximal venous stenosis
Kerr SF et al. Clin Radiol 2010 ; 65 : 744 – 749.
Pronounced aliasing at site of stenosis
Peak Systolic Velocity: 610 cm/s
Cephalic vein – Mid upper arm
73. Distal venous stenosis
Deklunder G et al. EMC-Radiologie 2004 ; 1 : 632 – 646.
Pronounced aliasing at site of stenosis
Peak Systolic Velocity: 340 cm/s
Junction of basilic & axillary vein
74. Stenosis of graft insertion on vein
Deklunder G et al. EMC-Radiologie 2004 ; 1 : 632 – 646.
Rail aspect of the graft
Aliasing on color Doppler
Peak Systolic Velocity : 400 cm / s
75. Pseudo-diagnosis of significant stenosis
Kerr SF et al. Clin Radiol 2010 ; 65 : 744 – 749.
PSV: 570 cm/sec
Brachio-basilic fistulaBrachial artery
PSV: 350 cm/sec
Volume flow:1.1 L/min
High inflow
Basilic vein
PSV: 175 cm/sec
Volume flow:1.8 L/min
High outflow
High PSV in anastomosis due to high flow volume & large vessels
76. Occlusion of brachiocephalic fistula
Triphasic waveform
RI = 1 (thrombosed fistula)
Brachial artery
Occlusion of fistula
Thrombus within draining vein
Brachio-cephalic fistula
Kerr SF et al. Clin Radiol 2010 ; 65 : 744 – 749.
77. Thrombosis in draining vein of AVF
Edenberg Jan et al. Tidsskr Nor Legeforen nr. 2009 ; 129 : 1635 – 8.
Pieturaa R et al. Eur J Radiol 2005 ; 55 : 113 – 119.
Complete thrombosis Partial thrombosis
79. Aneurysm
Develops in AVF functioning for many years
• Good function Lumen not filled with thrombus
Intact skin
• Intervention Intra-luminal thrombus
rarely needed Compromise of overlying skin
Steadily & rapidly enlarged
Obstructive kinks
• Operation Proximal A-V access of arterialized vein
Prosthetic graft
Padberg FT et al. J Vasc Surg 2008 ; 48 : 55S – 80S.
80. Diffuse aneurysmal dilation
Schäberle W. Ultrasonography in vascular diagnosis.
Springer-Verlag, Berlin Heidelberg, 2nd edition, 2011.
Secondary to wall degeneration or downstream stenosis
Feeding artery
Draining vein
Anastomosis
81. True venous aneurysm
Diffuse aneurysmal dilation
Bourquelot P et al. Nephrol Ther 2009 ; 5 : 239 – 248.
Kerr SF et al. Clin Radiol 2010 ; 65 : 744 – 749.
Raise concern from the staff
Radio-cephalic AVF Color Doppler US
82. Pseudoaneurysm
• Incidence 2 – 10 % during functional life of graft
Less frequent in AVF
• Doppler US Color Doppler: “yin -yang pattern”
Pulsed Doppler: “to-and-fro waveform”
Perianeurysmal fluid collection suggest infection
• Location Puncture site Observation if small & stable
Treatment if expanding
Anastomotic Generally requires surgery
Infection is common cause
Padberg FT et al. J Vasc Surg 2008 ; 48 : 55S – 80S.
83. Anastomotic pseudoaneurysm on A-V graft
Kabalci YM et al. Transplant Proc 2006 ; 38 : 2816 – 2818.
Brachio-basilic graft 2 months ago
Anastomotic pseudoaneurysm of graft is rare
84. Pseudoaneurysm
Color Doppler
“yin -yang pattern”
Pulsed Doppler
“to-and-fro waveform”
Schäberle W. Ultrasonography in vascular diagnosis.
Springer-Verlag, Berlin Heidelberg, 2nd edition, 2011.
85. Perivascular space with pulsatile flow
Bidirectional blood flow
Typical “yin-yang sign”
Pseudoaneurysm of radial artery
Color duplex US Thrombin injection under US control
Complete thrombosis after
thrombin injection
Carrafiello G et al. Injury Extra 2006 ; 37 : 78 – 81.
87. Hematoma
Kerr SF et al. Clin Radiol 2010 ; 65 : 744 – 749.
AV access punctured thrice weekly for hemodialysis
Serial examinations to monitor evolution of hematoma
89. Radial artery steal
Finlay DE et al. RadioGraphics 1993 ; 13 : 983 – 999.
Ulnar artery flow contributes to fistula flow via palmar arches
Retrograde flow in distal radial artery
90. Arterial steal syndrome
Clinical diagnosis – Incidence (1 – 4 %)
• Risk factor Brachial arterial, DM, female gender
• Symptoms Steal phenomenon Silent (70% of RC-AVF)
Steal syndrome Mild: pain during dialysis
Severe: rest pain, ulceration
Common cause of neuropathy
• Doppler US Reversed flow: complete – only in diastole
Dynamic study: gentle compression of AVF
• Treatment Ligation, banding, rerouting
Padberg FT et al. J Vasc Surg 2008 ; 48 : 55S – 80S.
91. Radial arterial steal
Frequent in asymptomatic patients
Wiese P et al. Nephrol Dial Transplant 2004 ; 19 : 1956 – 1963.
Fistula supplied by proximal radial artery (red, antegrade flow)
Fistula supplied by distal radial artery (blue, retrograde flow)
92. Reversed flow in distal RA after AVF
Goldfeld M et al. AJR 2000 ; 175 : 513 – 516.
Reversed flow during entire cardiac phase
93. Arterial steal syndrome
Radial-cephalic fistula
Yilmaz C et al. AJR 2009 ; 193 : W567.
RA distal to anastomosis
Antegrade flow during systole
Retrograde flow during diastole
Gentle compression of fistula
Restoration of antegrade flow
Elevated systolic flow
Elevated diastolic flowBidirectional flow
94. Hand ischemia in A-V access for hemodialysis
• Arterial steal syndrome Most common
• Proximal arterial stenosis Overlooked
• Atherosclerosis in hand & forearm Arteriography
• Regional venous hypertension
• Emboli of thrombosed A-V access Doppler US
Padberg FT et al. J Vasc Surg 2008 ; 48 : 55S – 80S.
95. Digital ischemia from emboli of thrombosed AVF
7 reported cases in the literature
Journet J et al. Néphrologie & Thérapeutique 2010 ; 6 : 121 – 124.
Digital ischemia
4 fingers of right hand
Regression of ishemia
6 mth after operation
Partial thrombosis
of RC-AVF
97. High-output cardiac failure
Rare &unusual complication
• Symptom Symptoms of right heart failure
Nicoladoni-Branham sign: ↓ PR after AVF occlusion
• Diagnosis Flow volume > 3 L/min
Flow volume/cardiac output ≥ 30% (screening)
Cardiac output > 2.3 L/min/m2
Sine qua none: improvement after treatment
• Treatment Ligation: sacrifice of access
Banding: more attractive option
Padberg FT et al. J Vasc Surg 2008 ; 48 : 55S – 80S.
98. Conclusion
• Doppler uplex US should be interpreted in conjunction with
clinical findings including adequacy of dialysis
• Results should be discussed within multidisciplinary team:
Nephrologist, vascular surgeon, & interventional radiologist
• Stenosis in early postop period interpreted with caution
They may be secondary to transient edema
• Duplex sonography is central to prevention, detection, and
management of complications
Kerr SF et al. Clin Radiol 2010 ; 65 : 744 – 749.
99. References
1. Kerr SF et al. Duplex sonography in the planning & evaluation of
arteriovenous fistula for hemodialysis Clin Radiol 2010;65:744-749.
2. Wiese P et al. Color Doppler ultrasound in dialysis access. Nephrol
Dial Transplant 2004;19:1956-1963.
3. Padberg FT et al. Complications of arteriovenous hemodialysis
access: recognition and management. J Vasc Surg 2008;48:55S-80S.
4. Konner K et al. The arteriovenous fistula. J Am Soc Nephrol 2003;
14:1669-1680.
5. Pieturaa R et al. Color Doppler ultrasound assessment of well-
functioning mature arteriovenous fistulas for haemodialysis access.
Eur J Radiol 2005;55:113-119.
6. Deklunder G et al. Exploration des vaisseaux du membre supérieur:
Doppler et échotomographie. EMC-Radiologie 2004;1:632-646.
The arm develops good collateral circulation around diseased segments.Subclavian artery diameter: 0.6 - 1.1 cmAxillary artery diameter of : 0.6 - 0.8 cm Deep brachial: divides from main trunk of brachial artery in upper arm & acts as collateral around elbow if brachial artery occluded distally.Common interosseous artery: important branch of ulnar artery in upper forearm & act as collateral if radial & ulnar arteries are occluded.The radial artery supplies deep palmar arch in the hand, and ulnar artery supplies superficial palmar arch.There are usually communicating arteries between the two systems.In some people only one of the wrist arteries will supply the palm arch system.The fingers are supplied by the palmar digital arteries
Blush: تورد احمرار
Vein diameters have considerable day-to-day variation and depend on examination conditions (ambient temperature and patient position). Therefore, veins should be evaluated under optimal conditions & venous distensibility tested in the case of apparently small veins.
The Doppler spectrum, especially at reactive hyperaemia useful to predict the risk of low flow steal
In 1929, Dr. Edgar van Nuys Allen described a maneuver in which the dual palmar circulation could be tested by obstructing both radial and ulnar arterial flow, then releasing either ulnar or radial to see if palmar circulation was restored. Compression of both radial and ulnar arteries is used while the fist is clenched, then the fist is relaxed revealing blanched palm. For the test results to be defined as positive for radial artery insufficiency, the blanching continues 5 seconds or more after release of radial artery compression while the ulnar artery compression continues. For the test results to be defined as positive the ulnar artery insufficiency,blanching continues 5 seconds or more after release of ulnar artery compression while the radial artery compression continues.The importance of this test is to ascertain the duality of the circulation, so that if one of the arteries was obstructed (from thrombus or spasm after puncture), the palmar circulation would not be compromised. Although there is some debate as to the value of Allen’s test in predicting who is at risk of hand ischemia, the test continues to be performed on a routine basis, especially in the setting of radial artery harvesting for coronary bypass grafting.
Measurements of the vein diameter were recorded from the ultrasound scan images at eight representative sites:the wrist, distal forearm, mid forearm, proximal forearm, antecubital fossa, distal upper arm, mid upper arm, and proximal upper arm.
The ground-breaking article by Brescia and Cimino in 1966 revolutionized the creation of the vascular access, and the Cimino fistula was soon used in almost all dialysis patients.To minimize the risk of hand ischemia, candidates for a radialcephalic AV fistula should have a normal preoperative Allen’s test to confirm a patent palmar arch.
All these techniques have advantages and disadvantages.
Poly Tetra Fluoro Ethylene (PTFE):Maturation period of 2–3 weeks for primary cannulation.Polyurethane:Three-layered polyurethane material. It is claimed that solid non-permeable medial layer has self-sealing properties, allowing a cannulation within 24 hafter implantation.Similar patency rates compared with ePTFE grafts
PTFE grafts currently account for 80% of primary vascular accesses created in the United States, but they are less frequently used in other countries. It has been increasingly recognized that outcomes of PTFE grafts are poorer.
Doppler spectrum showing the measurement of PSV & EDV.Mean velocity can be calculated from the Doppler spectrum, displayed by the black line. A large sample volume allow the blood velocity at anterior and posterior walls, as well as in center of the vessel, to be estimated but may not detect the flow along the lateral wall. Time-averaged mean velocity (TAM) can be found by averaging the mean velocity over one or more complete cardiac cycles. Volume flow can be calculated by multiplying the TAM measurement by the cross-sectional area of the vessel.Reference:Thrush A, Hartshorne T. Peripheral vascular ultrasound: How, why and when.Elsevier Churchill Livingstone, London, 2nd edition, 2005.
Bloom: يزدهر - ينتفخIn B-mode images, the vessel walls appear larger than their true anatomic size. This is due to the so-called blooming effect resulting from strong reflection of the ultrasound beam at the boundary between tissues of different acoustic impedance. The measurement errors can be minimized and systematized by using the leading-edge method and a low gain. Using the leading-edge method, the diameter is measured from the reflection of the outer wall to that of the oppositeinner wall
The larger the angle of insonation, the greater the potential source of error in velocity measurement.
c’est l’évolution du débit au cours de mesures successives, plus que sa valeur absolue au cours d’un examen, qui est importante.
In the US, hemodialysis is typically performed at a dialysis blood flow rate of 350–450 mL/min for 3.5–4 hours three times/week.Flow volume At least 500 mL/minFlow withdrawn at hemodialysis 350 mL/minFlow to keep the fistula patent 150 mL/min
Several investigators have suggested that duplex sonography could also be valuable in the routine surveillance of fistulae in asymptomatic patients based on the premise that the timely treatment of stenosis should help not only to prevent occlusion but also, in the early postoperative period, to facilitate fistula maturation.
La détermination de l’indice de résistance, normalement inférieur à 0,70, dans le cas d’une fistule non compliquée, permet de détecter très simplement la présence d’un obstacle à l’écoulement sur le circuit de la FAV. Un indice de résistance supérieur à 0,70 est évocateur d’une sténose critique de la veine de drainage associée à un haut risque dethrombose de la fistule.Un indice de résistance égal à 1 signe le diagnostic de thrombose de la fistule.
velocity measurements should not be interpreted in isolation in particular an elevated peak systolic velocity through an anastomosis may simply represent high flow volume in association with relatively large calibre inflow and outflow vessels
Incidence: 1.8% in arteriovenous fistulas and 4.3% in arteriovenous graftsIn patients with unrecognized or uncorrected steal, persistence of severe ischemia may produce devastating results such as a nonfunctional extremity with unremitting chronic pain or gangrene with loss of digits or limbs. Ischemic monomelic neuropathy: Rare but devastating complication.The term refers to combination of ischemia & neuropathy in a single limb (melos is Greek for limb).Recognition of IMN is difficult because it occurs so infrequently.The KDOQI Clinical Practice Guideline recommends emergency vascular access surgical consultation for these symptoms.Other causes of neuropathy : uremic neuropathy, diabetic neuropathy, carpal tunnel syndrome, and other compartment syndromes, such as the cubital or ulnar nerve compression syndrome.
74-year-old woman with a right-arm radiocephalic fistula presented with hand pain, coldness, and trophic changes in the distal aspects of the second and fourth fingers. Duplex Doppler examination revealed a patent fistula with a flow volume of 840 mL/min. No perianastomotic venous or arterial stenosis was detected.
Typical symptoms and findings are those of right heart failure: Dyspnea at rest, dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea, reduced exercise tolerance, peripheral edema, pulmonary edema, cardiomegaly, increased blood volume, & tachycardia. One report estimated that the mean slowing of the pulse rate in recognized high-output cardiac failure was approximately 7 beats/min.Improved methods for noninvasive characterization of AV access flow and cardiac output will distinguish AV access–related high-output cardiac failure from other common causes of these symptoms, such as anemia, HTN, inadequate dialysis, and fluid/electrolyte retention.