Should Infants Be Treated With vWF Concentrate After Cardiac Surgery?
Researchers comment on the implications of treating newborns and infants with von Willebrand factor (VWF) concentrate.
Some newborns and small infants who undergo major cardiac surgery with cardiopulmonary bypass (CPB) may benefit from procoagulant interventions to address perioperative bleeding. However, this may not be the case for newborns and small infants who show acquired von Willebrand syndrome (aVWS) following CPB.1
Commenting on a study published in the Journal of Thrombosis and Haemostasis, Mario Rannucci, MD, of the IRCCS Policlinico San Donato in Italy, and colleagues wrote that the paper “provides more questions than answers.”2
In the study being reviewed, Vanya Icheva, MD, of the University Children's Hospital Tübingen in Germany, and colleagues evaluated the intraoperative incidence and effect of aVWS following CPB in neonates and infants with complex congenital heart disease. Cardiac surgery for newborns and infants with complex congenital heart disease is associated with high rates of intraoperative bleeding complications. Anatomic features that are often observed in these cases include valve stenoses or patent arterial ducts, which in turn can lead to enhanced shear stress in the blood stream and subsequent aVWS.
The researchers' cohort included 12 patients aged 12 months or younger who underwent complex cardiac surgery at a tertiary referral center. The patients were measured for von Willebrand factor (VWF) antigen, ristocetin cofactor activity, collagen binding activity, VWF multimers, and factor VIII (FVIII) activity. An aVWS pattern was observed in 83% of the patients before surgery and in 66% after the procedure. In an attempt to control severe postoperative bleeding, 10 of the 12 patients received VWF/FVIII concentrate along with several other treatments. The intervention was tolerated well; no patients experienced intraoperative thrombotic events, although 1 patient experienced a transient postoperative cerebral sinuous vein thrombosis.
The study authors concluded that these data may “offer a new approach to reduce the risk of severe bleeding and to achieve hemostasis during high‐risk pediatric cardiac surgery by tailoring the substitution with VWF concentrate.”
Dr Rannucci and colleagues noted that this study is important because it is the ﬁrst report about aVWS in newborns and small infants who have undergone cardiac surgery. These results are different from what has been reported for adult patients, for whom aVWS generally remains uncorrected. They point out that there are multifactorial reasons for perioperative bleeding in this population, with certain factors being unique to infants. As with adult patients, complex cardiac surgery in neonates and infants involves thrombocytopenia, platelet dysfunction, dilution and consumption of soluble coagulation factors and ﬁbrinogen, and hyperﬁbrinolysis. In newborns and small infants, however, the hemostatic pattern is quite different because they have lower plasma concentrations of most procoagulant and anticoagulant proteins. These characteristics provide an effective hemostatic balance that settles at a lower level compared with adults. The exception is VWF; newborns have increased VWF activity and a higher level of high molecular weight VWF multimers.