NN&I - June 2010

Vascular Access 34 Nephrology News & Issues June 2010Subscribe to our free eNewsletter at www.nephronline.com Counterpoint: why surveillance is neededBy John Kennedy Mr. Kennedy is the president of Vasc-Alert, a West Lafayette, Ind. company that offers proactive sur-veillance of hemodialysis patients' access sites by evaluating intra-access pressure. Vascular access problems are a daily occurrence in busy dialysis units. Low blood flow rates and loss of patency limit dialysis delivery, extend treatment times, and result in inadequate dialysis. The recent update to the Conditions for Coverage, with its expanded focus on diagnosis and prevention of vascu-lar access problems, underscores CMS' commitment to improved clinical care. We know that thrombosis is a lead-ing cause of loss of vascular access pat -ency, and that stenosis is a precursor to thrombosis. These events are expen-sive to fix, are painful for the patient, and often require hospitalization. They also impact the center (missed treat -ments) and the payer of record (higher costs). When an access is lost, often the patient must then dialyze using catheters and accept inferior mortality and morbidity outcomes. Today, 19% of dialysis patients are on permanent catheters because they have exhausted other vascular access options.1 The authors of "Is there a need to mandate vascular access surveillance?" (on page 30) have taken issue with the evidence basis for the Conditions for Coverage's position on vascular access surveillance. They argue that there is no randomized controlled study show -ing that the use of a surveillance pro- tocol can extend the life of an access. They also argue that it is not proven that surveillance reduces thrombosis, at least in synthetic grafts, and that sur -veillance may even cause harm. They propose that CMS should only require the use of physical examination (moni -toring), and not surveillance. Yet, there has not been a randomized controlled study done that shows that physical examination extends the life of the access or reduces thrombectomies. Using pure evidence-based criterion, even doing a routine physical examina -tion of the access should not be required by CMS. If this were the case, dialysis providers would not be required to do anything to evaluate the access until it clots. Unfortunately, this is exactly what is happening in many large, busy dialy-sis units with staffing challenges and a high patient-to-physician ratio.While there is no large randomized controlled study that shows evidence of extension of access life when surveil-lance is used, many published stud-ies (some randomized) show benefit of surveillance for thrombosis reduction. Tessitori2,3, Sands4, Hoeben5, McCarley6, Roberts7, Glazer8, and Besarab9 all demonstrate 45% to 90% reductions in thrombosis rates in fistulas and/or grafts when surveillance is used. More- over, both Tessitori and Roberts showed a 50% to 95% reduction in catheter placements. My company participated in a large pilot to introduce surveil-lance into ten centers with 650 patients. Before surveillance, the baseline clot rate was over 40%. During the five months of the pilot, this rate dropped to 12%. Moreover, the false positive rate was only 4%, which mitigates the auth-ors' fears of unnecessary interventions.A physical examination of the access by a skilled clinician can be effective. But few centers have staff that are ade -quately trained, let alone with the time to do even monthly exams. So it would seem that the option to 'just do moni-toring' would not provide adequate access care. Monitoring and surveil -lance can be complementary, and can help to ensure that interventions are done at the right time. Surveillance, when done right, can positively impact vascular access out -comes. Building upon such important efforts as the Fistula First initiative, we, with others, look forward to growing the evidence base and clinical knowl-edge of this over time. References1. ESRD Clinical Performance Measures Project. 2007 page 27 2. Tessitore N et al. Adding access blood flow sur -veillance to clinical monitoring reduces thrombosis rates and costs, and improves fistula patency in the short term: a controlled cohort study. Nephrol Dial Transplant. 2008 Nov;23(11):3578-84. Epub 2008 May 29 3. Tessitore N, Bedogna V, Poli A, Impedovo A, Antonucci F, Teodori T, Lupo A; Triveneto Section of the Italian Society of Nephrology. Practice pat-terns in the management of arteriovenous fistula stenosis: a northern Italian survey. J Nephrol. 2006 Mar-Apr;19(2):200-4 4. Sands JJ, Jabyac PA, Miranda CL, Kapsick BJ. Intervention based on monthly monitoring decreases hemodialysis access thrombosis. ASAIO J. 1999 May-Jun;45(3):147-50 5. Hoeben H, Abu-Alfa AK, Reilly RF, Aruny JE, Bouman K, Perazella MA. Vascular access surveil-lance: evaluation of combining dynamic venous pressure and vascular access blood flow measure-ments. Am J Nephrol. 2003 Nov-Dec;23(6):403-8. Epub 2003 Oct 17 6. McCarley P, Wingard RL, Shyr Y, Pettus W, Hakim R, Ikizler TA. Vascular access blood flow monitor -ing reduces access morbidity and costs. Kidney Int 60:1164-1172, 2001 7. Roberts AB, Kahn MB, Bradford S, Lee J, Ahmed Z, Fitzsimmons J, Ball D. Graft surveillance and angioplasty prolongs dialysis graft patency. J Am Coll Surg. 1996 Nov;183(5):486-92 8. Glazer S, Diesto J, Crooks P, Yeoh H, Pascual N, Selevan D, Derose S, Farooq M. Going beyond the kidney disease outcomes quality initia-tive: Hemodialysis access experience at Kaiser Permanente Southern California. Ann Vasc Surg 20 : 75-82, 2006 9. Besarab A, Sullivan KL, Ross RP, Moritz MJ. Utility of intra-access pressure monitoring in detecting and correcting venous outlet stenoses prior to thrombosis. Kidney Int 1995;47:1364 -1373 VascAccess_NNI0610_6.indd 34 5/14/10 5:27:13 PM