Shear-stress induced acquired von Willebrand syndrome in children with congenital heart disease.

Abstract

To determine the frequency and severity of acquired von Willebrand syndrome (AVWS) in children with stenotic congenital heart disease (CHD) before and after intervention. In this single-centre prospective observational case-control study, 50 children [median age: 26 (range, 0-175) months, bodyweight: 9.5 (2.2-7.5) kg] underwent catheter interventions or cardiac surgery. A total of 26 children with high stenosis [mean gradient: 80 (range, 52-130) mmHg] represented the stenosis group and 24 without relevant stenosis (<20 mmHg) served as the control group. von Willebrand factor (VWF) was analysed with respect to quantity and function before and after corrective or palliative intervention. Demographic data were comparable. The stenosis group had more surgical and the control group more interventional procedures (P = 0.025). Before intervention, 13 patients from the stenosis group (50%) showed a significant reduction in VWF-multimers compared with no patients in the control group (P <0.001). Collagen binding capacity (VWF:CB) was lower in the stenosis group [0.5 (0.2-2.6) U/ml vs 0.8 (0.4-2.1) U/ml, P <0.05), as was the collagen binding capacity to antigen ratio (VWF:CB/Ag) [0.8 (0.4-1.4) U/ml vs 1 (0.4-1.7) U/ml, P <0.001). After intervention, VWF parameters normalized rapidly within the first 24 h after the procedure and showed no group differences. {VWF:CB [1.7 (0.6-3.7) vs 1.7 (0.6-4.2) U/ml, P = n.s.], VWF:CB/Ag [1.1 (0.5-2.9) vs 1.2 (0.7-2.2), P = n.s} Time in the intensive care unit, respirator time, duration of stay and bleeding before and after intervention were not significantly different. AVWS is detected in half of the children with high intra- or extracardiac stenoses and resolves completely after surgical or interventional repair. Even when undergoing surgery on cardiopulmonary bypass, excessive surgical site bleeding was not detected in our study patients.