A randomized controlled trial of interrupted versus continuous suturing techniques for radiocephalic fistulas

Objective: Continuous suturing techniques have conventionally been used for the end-to-side anastomoses of radiocephalic fistulas (RCFs); however, primary patency rates are poor. Only 50% to 60% of RCFs ever achieve functional patency. We hypothesized that a hybrid interrupted-continuous suturing technique (as used in many microsurgical procedures) may improve outcomes in fistulas constructed from small vessels. Methods: A randomized controlled trial comparing hybrid interrupted-continuous (n = 42) with continuous (n = 36) suturing techniques for RCF was undertaken. Patients were excluded if vessels were <1.8 mm in diameter or if previous ipsilateral fistula had been attempted. A priori power calculation indicated that a sample size of 78 patients was required to detect an improvement in patency from 50% to 80% (alpha =.05, beta =.8). The primary end point was primary patency at 6 weeks (assessed by a blinded observer for the presence of thrill and bruit). Secondary end points were immediate patency, functional patency (assessed clinically and by ultrasound) at 6 weeks, and presence of anastomotic stenosis. Results: Groups were comparable for basic patient demographics, operating surgeon, and vessel diameter as measured on preoperative ultrasound (mean age, 58.9 +/- 13 years; 68% male). Primary patency at 6 weeks was higher in the hybrid interrupted-continuous suturing technique group (71% vs 47%; P =.01). Immediate patency was also higher in the hybrid interrupted-continuous suturing technique group (93% vs 67%; P <.001). There was no significant difference in functional patency at 6 weeks (52% vs 36%; P =.18). Three patients developed an anastomotic stenosis. All were in the hybrid interrupted-continuous suturing technique group. One patient from the interrupted suturing technique cohort required re-exploration for bleeding. Conclusions: A hybrid interrupted-continuous suturing technique yielded higher immediate and 6-week primary patency rates for RCF. The hybrid interrupted-continuous suturing technique may improve anastomotic compliance and reduce the narrowing and puckering that can occur on suture tightening in small-caliber vessels. Based on these findings, consideration should be given to performing hybrid interrupted-continuous anastomoses for RCFs.