Coiled versus straight peritoneal dialysis catheters: a randomized controlled trial and meta-analysis

Background: Variations in peritoneal dialysis catheter design include differences in numbers of cuffs, shapes of subcutaneous paths (swan neck vs Tenckhoff), and shapes of intra-abdominal segments (straight vs coiled). The relative benefits of these designs have not been studied adequately. The objective of this study is to compare the clinical outcomes of coiled- versus straight-end swan neck peritoneal dialysis catheters.

Study design: Prospective randomized controlled trial (RCT); results were meta-analyzed with other RCTs of coiled versus straight catheters.

Setting & participants: 80 consecutive continuous ambulatory peritoneal dialysis patients were enrolled in the RCT. The meta-analysis considers data for 242 patients with coiled and 251 patients with straight catheters.

Intervention: Patients were randomly assigned to a coiled-end swan neck catheter (n = 40) or a straight-end swan neck catheter (n = 40) group.

Outcomes: Catheter tip migration with dysfunction (primary outcome) and catheter failure, catheter-related infection, technique failure, and all-cause mortality (secondary outcomes).

Results: The primary outcome occurred in 18 patients in the coiled group and 9 in the straight group. This difference was not statistically significant (HR, 1.96; 95% CI, 0.88-4.37; P = 0.09). Although rates of early (<8 weeks) catheter tip migration were similar between the 2 groups, we detected a significant association of the coiled design with increased risk of late (>8 weeks) catheter tip migration (HR, 6.43; 95% CI, 1.45-28.6; P = 0.005). The increased risk of overall catheter failure in the coiled group was not statistically significant (P = 0.06). In the meta-analysis, coiled catheters were associated significantly with increased risk of catheter tip migration (based on 4 trials: RR, 2.08; 95% CI, 1.30-3.33; P = 0.002).

Limitations: Single-center open-label experimental study powered to detect differences in only the most common complication of catheter tip migration with dysfunction. Our RCT examines only swan neck catheters, whereas the meta-analysis considers both swan neck and Tenckhoff designs.

Conclusions: Although we were unable to show statistically significant differences in the primary outcome in our RCT, pooled meta-analysis results suggest that coiled catheters may be more prone to migration and resultant dysfunction.