Background: Long-term central venous access devices (CVADs) are integral to cancer care provision. Despite the high prevalence of CVAD occlusion in children with cancer, strategies to prevent occlusive events are understudied. We aimed to test the safety and feasibility of conducting a randomized controlled trial (RCT) comparing heparinised saline, with normal saline (0.9% sodium chloride) for locking CVADs in pediatric cancer care.

Methods: A single center, parallel-group, pilot RCT was undertaken at a tertiary-referral pediatric hospital in Australia. Children ≤18 years with any CVAD who had been diagnosed with an oncological or malignant hematological condition, were eligible. Participants were 1:1 randomised to i) Normal or ii) Heparinised (10-100u/mL; CVAD type dependent) saline lock solutions. Study feasibility, occlusive events (complete, partial), thrombolytic use and adverse events (infections, medication errors) were assessed.

Results: Of the 217 patients assessed for eligibility, 61 children were recruited to the study and randomised to Normal (n = 30; 3,850 CVAD days) or Heparinised (n = 31; 4,036 CVAD days) saline. Eligibility (52%) and recruitment (54%) feasibility targets were not met. Protocol adherence was high (95% of assessments), with no attrition. Parent/caregiver satisfaction of interventions was high (median 10/10 clinicians and parents). Complete CVAD occlusion occurred in the Heparin group only (n = 2, 6.7% CVADs; incidence rate (IR) 0.49/1,000 CVAD days [0.06-1.78]). Partial occlusion was detected in 23.3% of CVADs in the Heparin group (n=7; IR 2.73/1,000 CVAD days [1.36-4.87]) and 13.8% of CVADs in the Normal saline group (n=4; IR 2.59/1,000 CVAD days [1.24 -4.77]). Thrombolytic agents were used in 16.7% of the Heparin group (5 CVADs) and 3.5% of the Normal saline group (1 CVAD). Adverse events did not differ between the groups.

Conclusions: Multi-site RCTs examining CVAD locks are safe, but strategies and resources to increase recruitment and eligibility are required.