Arteriovenous fistula survival and needling technique: long-term results from a randomized buttonhole trial.

BACKGROUND: We previously have shown that buttonhole needling is associated with a reduction in hematoma and postulated that buttonhole needling may increase long-term survival of an arteriovenous fistula (AVF). The purpose of this study was to evaluate AVF survival and complications in buttonhole versus standard needling. STUDY DESIGN: Long-term follow up of a randomized controlled trial in which participants were randomly assigned to standard or buttonhole needling and followed up until the AVF was abandoned or the study end date. SETTING & PARTICIPANTS: 140 long-term hemodialysis patients in Calgary, Alberta. INTERVENTION: Buttonhole needling with median time of exposure to the intervention of 13.2 (IQR, 7.8-19.4) months. OUTCOMES & MEASUREMENTS: Patients were prospectively followed up for study outcomes. Median follow-up times were 17.2 (IQR, 11.9-37.8) and 19.2 (IQR, 12.5-41.0) months for standard and buttonhole needling, respectively (P=0.2). The primary outcome was median access survival in months. Other outcomes included assisted and unassisted patency rates, rates of surgical and radiologic interventions, and time to abandonment (months) of buttonhole. RESULTS: Baseline characteristics were similar. The primary outcome, median access survival, was similar in both groups: 16.0 (IQR, 10.6-29.3) and 18.4 (IQR, 10.9-32.7) months for standard and buttonhole needling, respectively (P=0.2). There were 7 (10.1%) and 6 (8.6%) thromboses with standard and buttonhole needling, respectively (P=0.6). Median fistulogram rates were similar between techniques (P=0.2 with intention-to-treat analysis). Most patients (46 of 70) abandoned buttonhole needling by a median of 11.3 (IQR, 4.8-18.2) months. Median time to first infection for buttonhole needling was 11.1 (IQR, 4.9-30.0) months. There were no infections in standard needling of AVFs. LIMITATIONS: Findings are limited to patients needled by multiple hemodialysis nurses and not applicable to self-needlers. CONCLUSIONS: AVFs with buttonhole needling did not have improved survival. The lack of survival benefit and higher risk of infection should be noted when promoting buttonhole needling.