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


OBJECTIVE
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.
Division of Paediatric Cardiology, Department of Paediatrics and Adolescent Medicine             Division of Angiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria.
A
A
Hanslik
E
E
Kitzmüller
K
K
Thom
M
M
Haumer
W
W
Mlekusch
U
U
Salzer-Muhar
I
I
Michel-Behnke
C
C
Male
D016063:Blood Loss, Surgical; D006328:Cardiac Catheterization / Q000009:adverse effects*; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006493:Heparin / Q000009:adverse effects*; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D013927:Thrombosis / Q000209:etiology*
D006493:Heparin