KDOQI Guidelines. Overview. Predicting Successful Fistula Maturation Warren Gasper MD UCSF Vascular Surgery Fellow 2011 UCSF Vascular Symposium

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Kelley Farmer
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DISCLOSURES: NONE Predicting Successful Fistula Maturation Warren Gasper MD UCSF Vascular Surgery Fellow 2011 UCSF Vascular Symposium KDOQI Guidelines AV fistulas have better outcomes than grafts or

1 DISCLOSURES: NONE Predicting Successful Fistula Maturation Warren Gasper MD UCSF Vascular Surgery Fellow 2011 UCSF Vascular Symposium KDOQI Guidelines AV fistulas have better outcomes than grafts or catheters for dialysis access Goal for fistula prevalence is 65% Ideally, AVF is created prior to the initiation of dialysis (when egfr <30 ml/min/1.73m 2 ) and the patient will have functional permanent access at the initiation of dialysis Overview Definition of a mature fistula Using technical factors to predict maturation Using patient characteristics to predict maturation Future directions Am J Kidney Dis

2 Adequate fistulas and dialysis Robbins et al. >500ml/min and >4mm had 95% likelihood of success vs 33% if both negative Society Guidelines (expert recommendations) KDOQI: 600ml/min blood flow, 6mm diameter & 6mm deep within 6 weeks of surgery SVS: 500ml/min & 5mm at 4-6 weeks European Best Practice: 600ml/min & 5mm at 4 weeks For most patients, an AVF with 400ml/min blood flow and 4mm diameter will be sufficient Radiology 2002; Am J Kidney Dis 2006; JVS 2008; NDT 2007 Who gets a non-maturing fistula? 1. Patients over 65 years old 2. A patient without vein mapping 3. The patient with a fistula created by an intern 4. Patients with arteries and veins that do not remodel 8% 23% 4% 65% What technical factors are important? Preoperative ultrasound mapping Vein diameter, patency and compressibility Arterial diameter and wall characteristics Operative factors Intraoperative blood flow Surgeon experience Systematic review of risk factors for fistula non-maturation Radial artery diameter <2mm Cephalic vein diameter <2mm Intraoperative blood flow <170ml/min (radial) or <280ml/min (brachial) Relative risk of nonmaturation (95% CI) Estimated Sensitivity Estimated Specificity 1.5 (0.9 to 2.5) 38% 72% 1.9 (1.5 to 2.3) 38% 91% 3.5 (2.6 to 4.8) 50% 87% Standards for minimum vessel size and minimum intraoperative blood flow have moderate specificity for fistula non-maturation, but poor sensitivity Voormolen et al. JVS

9 years About 60% men, 40% women White 65%, African-American 29% Cause of

3 What about patient factors? Traditional cardiovascular risk factors Age Race Gender Diabetes Known CAD or PAD Who needs an AVF? In 2008, 110,000 patients were diagnosed with ESRD Median age 64.9 years About 60% men, 40% women White 65%, African-American 29% Cause of ESRD: Diabetes mellitus 45% Hypertension 30% Voormolen et al. JVS 2009 USRDS ADR 2010 Incidence of ESRD in the US Traditional risk factors and maturation USRDS ADR 2010 Lok et al, JASN

4 Predicting maturation today Intraoperative blood flow is the single best method for detecting a fistula at high risk for nonmaturation Preoperative vein and arterial mapping with duplex ultrasound using size criteria (cephalic vein <2mm, radial artery <2mm) can predict non-maturation Patient characteristics add little to predicting fistula maturation Maturation is a physiologic process 400ml/min 10ml/min 450ml/min 4-6 weeks 50ml/min 50ml/min Vascular physiology as a predictor of maturation EFAVF Study Looking for better phenotype of the AVF patient to develop better predictors which fistula will mature and what therapies might improve the maturation process Endothelium/flow mediated vasodilation (FMD) Arterial elasticity (pulse wave velocity) MRI/MRA characterization of AVF blood flow (volume, velocity, shear stress) and structure (diameter, geometry, wall thickness) Gene expression Serum inflammatory biomarkers AVF Maturation 4

AVF Hemodynamics Characterizing anatomy and flow after AVF creation with MRA V-HEALTH Study Extra-vascular allogeneic endothelial cells to improve AVF or AVG

005) Diabetics treated with EC matrix gel had more vein dilation at 24 weeks (+0.6mm vs -1.7mm, p=0.

dynamic physiologic process that involves remodeling of both the artery and vein Traditional cardiovascular risk factors poorly predict maturation Technical

5 AVF Hemodynamics Characterizing anatomy and flow after AVF creation with MRA V-HEALTH Study Extra-vascular allogeneic endothelial cells to improve AVF or AVG outcomes Subset analysis 31 AVF patients: Diabetics had significantly less vein dilation at 24 weeks (-0.6mm vs 2.3mm, p<0.005) Diabetics treated with EC matrix gel had more vein dilation at 24 weeks (+0.6mm vs -1.7mm, p=0.06) Conte, CJASN 2011, In Press Conclusions Patients needing AVF are older and have a high prevalence of cardiovascular co-morbidities AVF maturation is a dynamic physiologic process that involves remodeling of both the artery and vein Traditional cardiovascular risk factors poorly predict maturation Technical factor such as minimum vein and artery diameters and intraoperative blood flow are currently the best predictors of non-maturation Endothelial physiology is an attractive target for describing, predicting and eventually affecting fistula maturation 5

6 Thank you 6

AVF Prevalence. Local elastase to aid fistula maturation. I have nothing to disclose

AVF Prevalence. Local elastase to aid fistula maturation. I have nothing to disclose Local elastase to aid fistula maturation Warren Gasper MD UCSF Vascular Surgery Fellow 2013 UCSF Vascular Symposium I have nothing to disclose AVF Prevalence 60.6% (April 2012) Fistula First Initiative