ASDIN 7th Annual Scientific Meeting DISCLOSURES TECHNICAL CONSIDERATIONS TECHNICAL CONSIDERATIONS UTILITY OF ULTRASOUND IN EVALUATING ACCESS

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1 DISCLOSURES UTILITY OF ULTRASOUND IN EVALUATING ACCESS DYSFUNCTION None Vandana Dua Niyyar, MD Assistant Professor of Medicine, Division of Nephrology, Emory University UTILITY OF ULTRASOUND IN ACCESS DYSFUNCTION AVF: AVF Maturity Stenosis Angioplasty Thrombosis Clot Burden Steal syndrome AVG: Stenosis Angioplasty Pseudoaneurysm Peri-graft infection ADVANTAGES Non-invasive No need for contrast/radiation Widely available, Mobile Inexpensive Provides information on both morphology (vessel anatomy) and function (blood flow) of vascular access DISADVANTAGES Dependent on operator expertise Time consuming Limited it field of view provides focal imaging Difficult to visualize central/more proximal stenosis due to depth limitations TECHNICAL CONSIDERATIONS B-Mode: Sound wave travels through tissue and reflected back towards transducer Velocity of sound independent of tissue type can be converted to anatomic depth 2-dimensional image produced based on time interval and intensity of sound TECHNICAL CONSIDERATIONS Color Doppler Color superimposed on B-Mode image Degree of color saturation Flow velocity Hue Direction of flow BART: Blue Away, Red Towards 1

2 TECHNICAL CONSIDERATIONS Spectral Doppler Waveform analysis Quantitative measurement of velocity (, RI) SPECTRAL WAVEFORM Power Doppler Power of signal related to the number of RBC s (not velocity) Useful in slow flow/near occlusion Guidelines for noninvasive vascular laboratory testing. Journal of the American Society of Echocardiography Gerhard-Herman yr:2006 vol:19 iss:8 pg: RESPIRATORY PHASICITY HIGH-RESISTANCE ARTERY Malovrh. The Role of USS in planning AVF for HD. Seminars in Dialysis :4, Malovrh. The Role of USS in planning AVF for HD. Seminars in Dialysis :4, LOW-RESISTANCE AVF Malovrh. The Role of USS in planning AVF for HD. Seminars in Dialysis :4, CENTRAL VENOUS EVALUATION Frequent use of central catheters results in central vein stenosis Ultrasound unable to visualize the subclavian and brachiocephalic vein But may get indirect evidence of central venous abnormality using ultrasound Slide Courtesy: Dr Work 2

3 CENTRAL VENOUS EVALUATION AVF MATURITY FOR USE THROMBOSED GRAFT Patel et al Subclavian and internal jugular veins at Doppler US: abnormal cardiac pulsatility and respiratory phasicity as a predictor of complete central occlusion. Radiology. 211: AVF MATURITY FOR USE If fistula diameter was 0.4 cm or greater, the chance that it would be adequate for dialysis was 89% versus 44% if size was less. If fistula blood flow was 500 ml/min or greater, the chance that it would be adequate was 84% versus 43% if it was less. Combining the two variables, the chance that it would be adequate was 95% versus 33% if neither of the criteria were met. Experienced dialysis nurses had a 80% accuracy in predicting the ultimate utility of a fistula for dialysis. Robbin et al. Radiology 2002; 225: Luminal diameter reduction > 50% Peak systolic flow velocity () > 400 cm/sec ratio across stenosis >2.0 High resistance Doppler waveform Decrease in access flow volume Percent stenosis: (Original lumen residual lumen)/ Original lumen Sensitivity 76-87% cf. angiography Middleton et al. CD of HD access: comparison with angiography. Am J Radiol 1989; 152: Tordoir et al. Duplex USS in assessment of AVF for HD: comparison with DSA. J Vasc Surg 1989; 10: cm/s 636 cm/s 12 Grogan et al. Freq of critical stenosis in primary AVF: Shd Duplex USS be std of care? J Vasc Surg 2005; 41:

4 Prospective study 103 patients: Pre-operative US to evaluate anastomotic and juxta-anastomotic anastomotic stenosis 91% sensitivity and 98% specificity Salman, Asif et al: Accuracy of US in detection of inflow stenosis in AVF. Seminars In Dialysis, 23: 2010 Salman, Asif et al: Accuracy of US in detection of inflow stenosis in AVF. Seminars In Dialysis, 23: 2010 ACCESS FLOW VOLUME PTFE AVG Measure anywhere along the access Flow < 650 ml/min steadily increasing RR of thrombosis AVF Measure at feeding brachial artery/avf Flow < 300 ml/min access dysfunction Salman, Asif et al: Accuracy of US in detection of inflow stenosis in AVF. Seminars In Dialysis, 23: 2010 ACCESS FLOW VOLUME ANGIOPLASTY Duplex guided balloon angioplasty Small, uncontrolled studies Successful in both grafts 1 and fistulae 2 May be used intra-operatively for arterial stenosis May be used post-operatively operatively for immature/failing AVF 1. CD USS PTA of grafts. Bacchini et al. Journal of Vascular Access 2007; 8: Duplex-guided balloon angioplasty of AVF: A new office-based procedure. Ascher et al. J Vasc Surg 2009; 50:

5 ANGIOPLASTY May be used intra-operatively for arterial stenosis 7 patients with arterial stenosis, diagnosed pre- operatively by USS Dimensions i of angioplasty balloon decided d pre- operatively by USS Wires, balloons and stents inserted through the arteriotomy; inflation 8-13 atm for 30 sec 5 AVF matured and were successfully used 2 AVF (stents) unsuccessful Intra-op USS guided angioplasty of arterial stenosis during upper limb AVF creation. Napoli et al. Journal of Vascular Access 2007; 8:97-02 ANGIOPLASTY 32 office-based procedures on 25 patients Non-maturing (27) and failing (5) AVF All 5 failing AVF salvaged 24/27 successfully used for dialysis within 3 months after last procedure Primary cumulative patency at 1, 3 and 6 months: 96%, 76% and 53% Duplex-guided balloon angioplasty of AVF: A new office-based procedure. Ascher et al. J Vasc Surg 2009; 50:594-9 THROMBUS BURDEN COLOR DOPPLER - STEAL COLOR DOPPLER - STEAL NORMAL GRAFT

6 VECTRA GRAFT GRAFT CD USS of polyurethane vascular graft for HD. Wiese et al. NDT (2003) 18: Toya et al. Periodic duplex USS with elective PTA in AVG. Surg Today : GRAFT OUTFLOW VEIN THROMBOSIS PERI-GRAFT INFECTION

7 GRAFT PSEUDOANEURYSM SUMMARY Non-invasive Widely available Avoids exposure to contrast/radiation Relatively inexpensive May be used across the spectrum for HD access pre-, intra- and post-operatively operatively An excellent tool in the interventionist s armamentarium though vastly under-utilized. utilized. 6 THANK YOU! 7