Access Flow Monitoring of Patients with Native Vessel Arteriovenous Fistulae and Previous Angioplasty

158

Abstract. Balloon angioplasty (PTA) is an established treatment modality for stenosis in dysfunctional arteriovenous fistulae (AVF), although most studies showing efficacy have been retrospective, uncontrolled, and nonrandomized. In addition, it is unknown whether correction of stenosis not associated with significant hemodynamic, functional, and clinical abnormality may improve survival in AVF. This study was a prospective controlled open trial to evaluate whether prophylactic PTA of stenosis not associated with access dysfunction improves survival in native, virgin, radiocephalic forearm AVF. Sixty-two stenotic, functioning AVF, i.e., able to provide adequate dialysis, were enrolled in the study: 30 were allocated to control and 32 to PTA. End points of the study were either AVF thrombosis or surgical revision due to reduction in delivered dialysis dose. Kaplan-Meier analysis showed that PTA improved AVF functional failure-free survival rates (P ϭ 0.012) with a fourfold increase in median survival and a 2.87-fold decrease in risk of failure. Cox proportional hazard model identified PTA as the only variable associated with outcome (P ϭ 0.012). PTA induced an increase in access blood flow rate (Qa) by 323 (236 to 445) ml/min (P Ͻ 0.001), suggesting that improved AVF survival is the result of increased Qa. PTA was also associated with a significant decrease in access-related morbidity by approximately halving the risk of hospitalization, central venous catheterization, and thrombectomy (P Ͻ 0.05). This study shows that prophylactic PTA of stenosis in functioning forearm AVF improves access survival and decreases access-related morbidity, supporting the usefulness of preventive correction of stenosis before the development of access dysfunction. It also strongly supports surveillance program for early detection of stenosis.

Section: Discussionsupporting

confidence: 74%

A Prospective Controlled Trial on Effect of Percutaneous Transluminal Angioplasty on Functioning Arteriovenous Fistulae Survival

Tessitore¹,

Mansueto²,

Bedogna³

et al. 2003

158

“…This is of course far less than what is required for optimal blood flow during dialysis. As a result of low blood flow, dialysis will become ineffective and recirculation will occur, but measurements of recirculation are considerably less sensitive to predict fistula malfunction and thromboses than direct measurements of fistula flow rates (53). The time course is more important than the absolute values.…”

Section: Monitoring Of the Fistulamentioning

confidence: 99%

The Arteriovenous Fistula

Könner¹,

Nonnast-Daniel²,

Ritz³

2003

282

221

The ground-breaking article by Brescia and Cimino in 1966 (1) revolutionized the creation of the vascular access, and the Cimino fistula was soon used in almost all dialysis patients. Unfortunately, subsequent wide-spread use of PTFE grafts instead of AV fistulae occurred because of the ease of the surgical technique, the immediate availability of the graft for puncture, the need of high blood flow for high-efficiency, short-duration hemodialysis sessions, and because of financial disincentives against the AV fistula. PTFE grafts currently account for 80% of primary vascular accesses created in the United States (2,3), but they are less frequently used in other countries. It has been increasingly recognized that outcomes of PTFE grafts are poorer. In the DOQI guidelines (4), this has led to the recommendation that AV fistulae should be the first option; however, this advice has not been followed uniformly. One impediment may be the astonishingly high rate of primary failures of AV fistulae, up to 50% in some centers (4). The DOPPS study (Figure 1) documented substantial differences between survival of PTFE grafts and AV fistulae and differences of survival of AV fistulae between the United States and other countries (3). On the basis of our experience, we are of the opinion that primary failure rates can be substantially improved by attention to small but important details of surgical technique. The DOQI guidelines state that AV fistulae are feasible only in 50% of the patients, but we (5) and others (6) found that construction of native AV fistulae is feasible in up to 90%.It is the purpose of this article (a) to provide some insights into the fascinating cellular biology and pathophysiology underlying the vascular adaptation to the creation of an AV fistula and (b) to describe some small, often neglected, but important technical details that determine the success of the procedure. It is the intention to improve results and to influence patterns of practice.

“…Measurements of access blood flow (Qa) have been shown to identify first and recurrent episodes of stenosis in patients with native vessel arteriovenous fistulae (AVF) (1,2). Canadian clinical practice guidelines recommend performing angiography in AVF when Qa is Ͻ500 ml/min (3), which is associated with a positive predictive value for stenosis of approximately 70%.…”

mentioning

confidence: 99%

Best Threshold for Diagnosis of Stenosis or Thrombosis within Six Months of Access Flow Measurement in Arteriovenous Fistulae

Tonelli¹,

Jhangri²,

Hirsch³

et al. 2003

Abstract. Canadian clinical practice guidelines recommend performing angiography when access blood flow (Qa) is Ͻ500 ml/min in native vessel arteriovenous fistulae (AVF), but data on the value of Qa that best predicts stenosis are sparse. Because correction of stenosis in AVF improves patency rates, this issue seems worthy of investigation. Receiver-operating characteristic curves were constructed to examine the relation-