Tunneled Hemodialysis Catheter Tip Design and Risk of Catheter Dysfunction: An Australian Nationwide Cohort Study

Rationale & Objective Hemodialysis catheter dysfunction is an important problem for patients with kidney failure. The optimal design of the tunneled catheter tip is unknown. This study evaluated the association of catheter tip design with the duration of catheter function. Study Design Observational cohort study using data from the nationwide REDUCCTION trial. Setting & Participants 4,722 adults who each received hemodialysis via 1 or more tunneled central venous catheters in 37 Australian nephrology services from December 2016 to March 2020. Exposure Design of tunneled hemodialysis catheter tip, classified as symmetrical, step, or split. Outcome Time to catheter dysfunction requiring removal due to inadequate dialysis blood flow assessed by the treating clinician. Analytical Approach Mixed, 3-level accelerated failure time model, assuming a log-normal survival distribution. Secular trends, the intervention, and baseline differences in service, patient, and catheter factors were included in the adjusted model. In a sensitivity analysis, survival times and proportional hazards were compared among participants’ first tunneled catheters. Results Among the study group, 355 of 3,871 (9.2%), 262 of 1,888 (13.9%), and 38 of 455 (8.4%) tunneled catheters with symmetrical, step, and split tip designs, respectively, required removal due to dysfunction. Step tip catheters required removal for dysfunction at a rate 53% faster than symmetrical tip catheters (adjusted time ratio, 0.47 [95% CI, 0.33-0.67) and 76% faster than split tip catheters (adjusted time ratio, 0.24 [95% CI, 0.11-0.51) in the adjusted accelerated failure time models. Only symmetrical tip catheters had performance superior to step tip catheters in unadjusted and sensitivity analyses. Split tip catheters were infrequently used and had risks of dysfunction similar to symmetrical tip catheters. The cumulative incidence of other complications requiring catheter removal, routine removal, and death before removal were similar across the 3 tip designs. Limitations Tip design was not randomized. Conclusions Symmetrical and split tip catheters had a lower risk of catheter dysfunction requiring removal than step tip catheters. Funding Grants from government (Queensland Health, Safer Care Victoria, Medical Research Future Fund, National Health and Medical Research Council, Australia), academic (Monash University), and not-for-profit (ANZDATA Registry, Kidney Health Australia) sources. Trial Registration Registered at ANZCTR with study number ACTRN12616000830493. Plain-Language Summary Central venous catheters are widely used to facilitate vascular access for life-sustaining hemodialysis treatments but often fail due to blood clots or other mechanical problems that impede blood flow. A range of adaptations to the design of tunneled hemodialysis catheters have been developed, but it is unclear which designs have the greatest longevity. We analyzed data from an Australian nationwide cohort of patients who received hemodialysis via a tunneled catheter and found that catheters with a step tip design failed more quickly than those with a symmetrical tip. Split tip catheters performed well but were infrequently used and require further study. Use of symmetrical rather than step tip hemodialysis catheters may reduce mechanical failures and unnecessary procedures for patients. Hemodialysis catheter dysfunction is an important problem for patients with kidney failure. The optimal design of the tunneled catheter tip is unknown. This study evaluated the association of catheter tip design with the duration of catheter function. Observational cohort study using data from the nationwide REDUCCTION trial. 4,722 adults who each received hemodialysis via 1 or more tunneled central venous catheters in 37 Australian nephrology services from December 2016 to March 2020. Design of tunneled hemodialysis catheter tip, classified as symmetrical, step, or split. Time to catheter dysfunction requiring removal due to inadequate dialysis blood flow assessed by the treating clinician. Mixed, 3-level accelerated failure time model, assuming a log-normal survival distribution. Secular trends, the intervention, and baseline differences in service, patient, and catheter factors were included in the adjusted model. In a sensitivity analysis, survival times and proportional hazards were compared among participants’ first tunneled catheters. Among the study group, 355 of 3,871 (9.2%), 262 of 1,888 (13.9%), and 38 of 455 (8.4%) tunneled catheters with symmetrical, step, and split tip designs, respectively, required removal due to dysfunction. Step tip catheters required removal for dysfunction at a rate 53% faster than symmetrical tip catheters (adjusted time ratio, 0.47 [95% CI, 0.33-0.67) and 76% faster than split tip catheters (adjusted time ratio, 0.24 [95% CI, 0.11-0.51) in the adjusted accelerated failure time models. Only symmetrical tip catheters had performance superior to step tip catheters in unadjusted and sensitivity analyses. Split tip catheters were infrequently used and had risks of dysfunction similar to symmetrical tip catheters. The cumulative incidence of other complications requiring catheter removal, routine removal, and death before removal were similar across the 3 tip designs. Tip design was not randomized. Symmetrical and split tip catheters had a lower risk of catheter dysfunction requiring removal than step tip catheters.