Low-Flow Polytetrafluoroethylene Accesses: Ultrasound Surveillance and Preemptive Interventions Ensure Long-Term Patency

Background: Vascular accesses (especially polytetrafluoroethylene grafts) with a permanently low flow (Qa < 600 ml/min) are prone to thrombosis and thus have short patency. The reason for a permanently low flow is usually medial calcinosis of the inflow artery in diabetics. We retrospectively studied the long-term patency of low-flow grafts with careful ultrasound surveillance and preemptive interventions. Methods: Twenty subjects with Qa permanently <600 ml/min were included. Ultrasound surveillance was performed every 3 months in addition to classical monitoring techniques. Significant stenosis was strictly defined as the combination of B-mode narrowing >50% + >2-fold peak systolic velocity increase + 1 additional criterion (residual diameter <2.0 mm or flow volume decrease by >20%). Such stenoses were treated by preemptive percutaneous intervention. Primary and secondary patencies were calculated. Results: The primary patency was 357 +/- 316 days and the secondary (cu- mulative) patency was 996 8 702 days. The number of interventions was 2.09/patient year, but >10 in 6 (33%) subjects. 93 and 80% of grafts were patent 1 and 2 years after access creation, respectively. Conclusion: Low-flow accesses undergoing ultrasound surveillance with strict diagnostic criteria and preemptive interventions had patencies similar to accesses with normal Qa in our study. This was enabled by a relatively high rate of interventions. Copyright (C) 2010 S. Karger AG, Basel