Monitoring and surveillance of hemodialysis arteriovenous grafts to prevent thrombosis
- Michael Allon, MD
Michael Allon, MD
- Professor of Medicine
- University of Alabama at Birmingham
- Section Editors
- Jeffrey S Berns, MD
Jeffrey S Berns, MD
- Editor-in-Chief — Nephrology
- Section Editor — Dialysis
- Professor of Medicine
- Perelman School of Medicine at the University of Pennsylvania
- John F Eidt, MD
John F Eidt, MD
- Section Editor — Vascular and Endovascular Surgery
- Professor of Surgery, Texas A&M Health Science Center
- Vice Chair of Vascular Surgical Services, Baylor Heart and Vascular Hospital at Dallas
- Joseph L Mills, Sr, MD
Joseph L Mills, Sr, MD
- Section Editor — Vascular and Endovascular Surgery
- Professor and Chief
- Division of Vascular Surgery and Endovascular Therapy
- Baylor College of Medicine
- David L Cull, MD
David L Cull, MD
- Section Editor — Arterial and Venous Access
- Clinical Professor, Department of Surgery
- University of South Carolina School of Medicine
Hemodialysis requires access to blood vessels capable of providing rapid extracorporeal blood flow. These requirements are currently best met by both primary arteriovenous (AV) fistulas and synthetic grafts. (See "Overview of chronic hemodialysis vascular access".)
Issues surrounding monitoring and surveillance of hemodialysis AV grafts in the attempt to prevent thrombosis and graft failure are presented in this topic review. Similar issues for hemodialysis AV fistulas are discussed separately. (See "Clinical monitoring and surveillance of the mature hemodialysis arteriovenous fistula".)
RATIONALE FOR MONITORING AND SURVEILLANCE OF ARTERIOVENOUS GRAFTS
The assessment of hemodialysis AV grafts for stenosis is performed using clinical monitoring and noninvasive surveillance methods. Unfortunately, the ability to detect stenotic lesions does not necessarily mean that clinical outcomes are improved, such as a decreased rate of thrombosis and/or improved graft survival .
More than 90 percent of thrombosed grafts have a stenotic lesion, suggesting that such an anatomic abnormality is required for graft thrombosis. Noninvasive monitoring methods have a relatively high positive predictive value (PPV) for detecting >50 percent graft stenosis. A randomized, controlled trial  found that abnormalities detected by clinical monitoring had a 70 percent PPV for hemodynamically significant AV graft stenosis compared with Duplex ultrasound, which had an 80 percent PPV. However, in general, fewer than half of grafts with >50 percent stenosis are destined to thrombose in the absence of preemptive angioplasty. Any type of program to preemptively identify and treat stenosis necessarily results in a substantial number of superfluous angioplasties. To complicate matters, the vascular injury resulting from angioplasty may actually stimulate neointimal hyperplasia and accelerate graft restenosis and potentially graft loss .
Clinical monitoring refers to assessments that can be performed by physical examination of the access or by using readily available information that is collected in the course of treating dialysis patients . A number of studies have observed that a hemodynamically significant (>50 percent) stenosis is present in approximately 70 to 90 percent of patients identified to have abnormalities of clinical monitoring [2,5-9]. The major advantages of clinical monitoring are it is free, it does not require additional equipment or personnel, and it can be performed by multiple staff members.
- Lumsden AB, MacDonald MJ, Kikeri D, et al. Prophylactic balloon angioplasty fails to prolong the patency of expanded polytetrafluoroethylene arteriovenous grafts: results of a prospective randomized study. J Vasc Surg 1997; 26:382.
- Robbin ML, Oser RF, Lee JY, et al. Randomized comparison of ultrasound surveillance and clinical monitoring on arteriovenous graft outcomes. Kidney Int 2006; 69:730.
- Chang CJ, Ko PJ, Hsu LA, et al. Highly increased cell proliferation activity in the restenotic hemodialysis vascular access after percutaneous transluminal angioplasty: implication in prevention of restenosis. Am J Kidney Dis 2004; 43:74.
- Allon M, Robbin ML. Hemodialysis vascular access monitoring: current concepts. Hemodial Int 2009; 13:153.
- Maya ID, Oser R, Saddekni S, et al. Vascular access stenosis: comparison of arteriovenous grafts and fistulas. Am J Kidney Dis 2004; 44:859.
- Cayco AV, Abu-Alfa AK, Mahnensmith RL, Perazella MA. Reduction in arteriovenous graft impairment: results of a vascular access surveillance protocol. Am J Kidney Dis 1998; 32:302.
- Robbin ML, Oser RF, Allon M, et al. Hemodialysis access graft stenosis: US detection. Radiology 1998; 208:655.
- Safa AA, Valji K, Roberts AC, et al. Detection and treatment of dysfunctional hemodialysis access grafts: effect of a surveillance program on graft patency and the incidence of thrombosis. Radiology 1996; 199:653.
- Schwab SJ, Raymond JR, Saeed M, et al. Prevention of hemodialysis fistula thrombosis. Early detection of venous stenoses. Kidney Int 1989; 36:707.
- Krivitski NM. Theory and validation of access flow measurement by dilution technique during hemodialysis. Kidney Int 1995; 48:244.
- Moist LM, Churchill DN, House AA, et al. Regular monitoring of access flow compared with monitoring of venous pressure fails to improve graft survival. J Am Soc Nephrol 2003; 14:2645.
- Schwab SJ, Oliver MJ, Suhocki P, McCann R. Hemodialysis arteriovenous access: detection of stenosis and response to treatment by vascular access blood flow. Kidney Int 2001; 59:358.
- 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.
- Besarab A, Frinak S, Sherman RA, et al. Simplified measurement of intra-access pressure. J Am Soc Nephrol 1998; 9:284.
- Ram SJ, Work J, Caldito GC, et al. A randomized controlled trial of blood flow and stenosis surveillance of hemodialysis grafts. Kidney Int 2003; 64:272.
- Dember LM, Holmberg EF, Kaufman JS. Randomized controlled trial of prophylactic repair of hemodialysis arteriovenous graft stenosis. Kidney Int 2004; 66:390.
- Malik J, Slavikova M, Svobodova J, Tuka V. Regular ultrasonographic screening significantly prolongs patency of PTFE grafts. Kidney Int 2005; 67:1554.
- McCarley P, Wingard RL, Shyr Y, et al. Vascular access blood flow monitoring reduces access morbidity and costs. Kidney Int 2001; 60:1164.
- Tonelli M, James M, Wiebe N, et al. Ultrasound monitoring to detect access stenosis in hemodialysis patients: a systematic review. Am J Kidney Dis 2008; 51:630.
- Miller CD, Robbin ML, Barker J, Allon M. Comparison of arteriovenous grafts in the thigh and upper extremities in hemodialysis patients. J Am Soc Nephrol 2003; 14:2942.
- Martin LG, MacDonald MJ, Kikeri D, et al. Prophylactic angioplasty reduces thrombosis in virgin ePTFE arteriovenous dialysis grafts with greater than 50% stenosis: subset analysis of a prospectively randomized study. J Vasc Interv Radiol 1999; 10:389.
- Dember LM, Holmberg EF, Kaufman JS. Value of static venous pressure for predicting arteriovenous graft thrombosis. Kidney Int 2002; 61:1899.
- McDougal G, Agarwal R. Clinical performance characteristics of hemodialysis graft monitoring. Kidney Int 2001; 60:762.
- Murray BM, Rajczak S, Ali B, et al. Assessment of access blood flow after preemptive angioplasty. Am J Kidney Dis 2001; 37:1029.
- Vascular Access 2006 Work Group. Clinical practice guidelines for vascular access. Am J Kidney Dis 2006; 48 Suppl 1:S176.
- RATIONALE FOR MONITORING AND SURVEILLANCE OF ARTERIOVENOUS GRAFTS
- CLINICAL MONITORING
- Intra-access blood flow monitoring
- Duplex ultrasonography
- Static venous dialysis pressure
- OUR APPROACH
- KDOQI RECOMMENDATIONS
- Indications for referral
- INFORMATION FOR PATIENTS
- SUMMARY AND RECOMMENDATIONS