Clinical performance and microstructural assessment of hemodialysis catheters for children on maintenance dialysis

Central venous catheters (CVCs) are the most common vascular access for pediatric hemodialysis (HD), despite frequent complications. We assessed outcomes of commonly used CVCs in children on maintenance dialysis comparing clinical outcomes with micro-CT and histology of the CVC after removal.

Data from children aged 0-18 years receiving maintenance HD were collected from three pediatric dialysis centers. CVC-related outcomes were analyzed to determine complication rates and access survival. CVC dysfunction and reasons for CVC removal were recorded. A consecutive subset of explanted CVCs was examined using high-resolution imaging (micro-CT) and histological sectioning to investigate the site, extent and nature of any occlusions.

Data were collected for 288 catheters (six sizes and six models) spanning 85,393 catheter-days. CVC dysfunction was recorded in 54.2% of the lines, most commonly due to infection (40.6%) and line occlusion (24.5%). The median CVC survival was 215.5 days, with 133 CVC replacements in 72 children. Infection rates ranged from 0.20 to 1.82 per 1000 catheter-days, depending on CVC size. Larger CVCs (≥ 14Fr) did not show better access survival compared to 10-Fr models, although this may be influenced by design differences. Micro-CT of 16 explanted CVCs revealed occlusions in all of them, with histological confirmation of thrombi in 7. Thrombi were rich in fibrin, implying an organized clot, and predominantly located in the region of the side holes and at the catheter tip.

Pediatric CVCs are associated with a high rate of dysfunction, leading to replacement in 44% of patients. Interestingly, diameters ≥ 10Fr (12.5Fr, ≥ 14Fr) were not associated with improved survival, whereas 8Fr catheters showed a non-significant trend toward increased occlusion and poorer catheter survival, suggesting a possible threshold effect. Micro-CT and histology confirmed the presence, site and extent of thrombi. These data can inform development and modeling of new CVC designs.