No abstract

Abstract. Screening strategies based on measurement of access blood flow (Qa) allow detection and angioplasty of subclinical stenosis in native vessel arteriovenous (AV) fistulae. However, little is known about the efficacy of Qa measurements for detecting recurrent stenoses in fistulae and that of angioplasty for correcting them. A total of 303 patients were studied over 30 mo; 69 (23%) of these had stenoses, of whom 53 underwent angioplasty. Of those undergoing angioplasty, 30 patients had 46 episodes of recurrent positive studies and underwent repeat fistulography. In 31 of these episodes (19 patients), stenosis was again identified and treated successfully with angioplasty. Overall positive predictive values for stenosis were similar in first and subsequent episodes of stenosis (71% versus 67%), and angioplasty was associated with sustained increases in Qa for both first and subsequent episodes. Assisted patency in fistulae that required repeat angioplasty was 87% (median follow-up 10 mo after the second angioplasty). In conclusion, Qa is effective for detecting first and subsequent lesions in patients with AV fistulae, and angioplasty of first or subsequent lesions is associated with sustained increments in Qa. Continued screening after correction of first stenoses appears reasonable, because of both the frequency of recurrent stenosis and the success of repeat intervention.Ultrasound dilution measurement of access blood flow (Qa) has been shown to accurately identify first episodes of subclinical stenosis in native vessel fistulae (1). Most such stenoses, once identified, are amenable to percutaneous angioplasty, which is associated with short-term improvements in Qa and dialysis delivery. Although access screening programs have been shown to prolong the use-life of polytetrafluoroethylene (PTFE) grafts (2) and cohorts of mixed access type (3), little data exists on the effect of such programs on native arteriovenous dialysis fistulae (4 -6).The diagnostic performance of Qa in native vessel fistulae that have previously undergone angioplasty for stenosis is unknown. The positive predictive value of screening might differ substantially in this population compared with unselected fistulae, both because of the prevalence of stenosis and because of mechanical effects of angioplasty on the native vessel conduit. Finally, the effectiveness of angioplasty for correcting recurrent stenoses in fistulae is unclear. These data will become increasingly relevant as access screening programs are implemented in more dialysis centers and the prevalence of fistulae with previously angioplastied stenosis increases.There were two objectives for the current study. The first was to determine the positive predictive value of ultrasound dilution techniques (UDT) for the detection of subclinical stenoses in fistulae that have previously undergone angioplasty. The second was to document the efficacy of angioplasty at correcting stenoses in fistulae that have previously undergone angioplasty. In both cases, results from those with ...