Evaluation of Central Line Thrombosis in Children with Heart Failure on Continuous Infusion Milrinone.

PURPOSE: Milrinone is utilized for hemodynamic support in heart failure (HF) patients. Due to reduced cardiac output and systemic blood flow, patients with HF are at increased risk of thrombosis. Central venous catheter (CVC) placement compounds this risk. The aim of this study was to determine the incidence of thrombosis, identify thrombosis risk factors, and determine the impact of anticoagulation in pediatric patients receiving continuous milrinone via CVC at the Medical University of South Carolina.

METHODS: This retrospective study evaluated HF patients less than 18 years of age receiving continuous milrinone infusion via CVC for greater than or equal to 14 days between July 2014 and July 2019. Patients were evaluated based on anticoagulation (AC) status: therapeutic, prophylactic, or none (NAC). The primary outcome measure was the incidence of thrombosis. Possible risk factors for thrombus formation analyzed included age, pathogenesis of heart failure, ventricular assist device (VAD) use, duration of milrinone, and type of CVC. Blood product, factor VII, and prothrombin complex concentrate (PCC) utilization during VAD placement and transplant were analyzed as safety endpoints.

RESULTS: A total of 35 patients were included - 16 patients receiving AC and 19 with NAC. There was no difference in thrombus formation between the AC and NAC groups [5 vs. 6; P = .49]. Of patients on prophylactic AC, 50% (n = 4) experienced a thrombus, compared to 25% (n = 12) of patients on therapeutic AC. Patients with CVC in place for greater than 300 days had an incidence of thrombosis of 83% (n = 6). Those receiving therapeutic AC used more PCC and Factor VII than the NAC group during transplant [17.37 units/kg vs. 0, P = .004, 74.74 mcg/kg vs. 18 mcg/kg, P = .025]. Those on therapeutic AC utilized more blood products than patients on prophylactic AC during both VAD placement and transplant (61.5 mL/kg vs. 3.5 mL/kg, P = .003) and NAC patients (61.5 mL/kg vs 24.6 mL/kg, P = .046).

CONCLUSION: Incidence of thrombosis was similar among anticoagulated and non-anticoagulated patients who were on continuous infusion milrinone. Higher total CVC days increased the risk of thrombosis. Prophylactic anticoagulation had a limited effect on thrombus formation, but did not increase blood product use during VAD and transplant procedures as compared to therapeutic anticoagulation.