Incidence of thrombotic and bleeding complications during cardiac catheterization in children: comparison of high‐dose vs. low‐dose heparin protocols

Abstract

Summary. Background: During cardiac catheterization (CC) in children, unfractionated heparin (UFH) is used for primary prophylaxis of thrombotic events (TE). However, the optimal UFH dose to minimize TE and bleeding in children has yet to be established. Objectives: To (i) objectively assess the incidence of TE and bleeding during pediatric CC using clinical assessment and ultrasound; and (ii) compare a high-dose vs. low-dose UFH protocol for thromboprophylaxis. Methods: A randomized controlled trial (RCT) comparing high-dose UFH (100 units kg )1 bolus, followed by 20 units kg h )1 continuous infusion) vs. low-dose UFH (50 units kg )1 bolus) during CC.Outcome assessment was by clinical examination and vascular ultrasound, performed by blinded examiners before and within 48 h after CC. Children with no consent for randomization were followed in a cohort receiving standard-of-care UFH (parallel-cohort RCT). Results: A total of 227 children were included; 137 were randomized and 90 followed in the cohort study. The overall incidence of TE was 4.6% and bleeding 6.6%. The RCT was stopped early for futility as there were no differences between the high-dose and the low-dose UFH in TE (5% vs. 3%; risk ratios [RR] 1.5, 95% confidence interval [CI] 0.3; 9) and bleeding (7% vs. 12%, RR 0.6, 95% CI 0.2; 2). There were also no differences when RCT and cohort study populations were combined. Conclusions: The incidences of TE and bleeding during CC in children were low. There were no differences between the high-dose and the low-dose UFH protocols studied. Although Heparin Anticoagulation Randomized Trial in Cardiac Catheterization (HEARTCAT) was not designed as non-inferiority trial, low-dose UFH (50 units kg )1 bolus) appears sufficient for thromboprophylaxis during CC.

Monitoring unfractionated heparin in children: a parallel-cohort randomized controlled trial comparing 2 dose protocols

“…26 Infants had an increased incidence of TE and bleeding independent of dose. To test whether the UFH effects actually achieved in plasma were associated with clinical outcomes, logistic regression was performed, without and with inclusion of the covariables UFH dose group, age, antithrombin at baseline, and sex.…”

“…26 Patients with no consent for randomization received UFH as per standard-of care and were followed in a parallel cohort (50 U/kg for venous diagnostic catheterization, 100 U/kg for arterial diagnostic and any interventional catheterization). Patients in the cohort study consented to clinical outcome assessment and laboratory testing.…”

“…26 Of 227 children enrolled in the overall study, 163 had blood samples taken for UFH monitoring. The blood samples of 14 patients could not be evaluated for the study for several, mostly technical reasons (eg, clotted sample, no heparin administered).…”

“…26 The present study reports the results of the laboratory substudy investigating the monitoring of UFH in children. The specific study objectives were (1) to investigate the relationship between UFH dose and UFH anticoagulant effect as assessed by various assays, (2) to assess other factors influencing the UFH effect, (3) to determine the agreement between these assays, and (4) to describe the association between UFH effect and clinical outcome.…”

Incidence and predictors of cardiac catheterisation-related arterial thrombosis in children

“…Several studies were focused on arterial thrombosis and on overall complications of CC 4 5 9 16 29 30. Other studies were designed to evaluate diagnostic tools to detect thrombosis or the effect of prophylactic administration of heparin to prevent arterial thrombosis or to evaluate the effect of different thrombolytic agents to dissolve arterial thrombosis after CC 8 10 12 13 18 19 21–23 25–28 32–34…”