Effect of 22q11.2 deletion on bleeding and transfusion utilization in children with congenital heart disease undergoing cardiac surgery.

Background: Postsurgical bleeding causes significant morbidity and mortality in children undergoing surgery for congenital heart defects (CHD). 22q11.2 deletion syndrome (DS) is the second most common genetic risk factor for CHD. The deleted segment of chromosome 22q11.2 encompasses the gene encoding glycoprotein (GP) Ibβ, which is required for expression of the GPIb-V-IX complex on the platelet surface, where it functions as the receptor for von Willebrand factor (VWF). Binding of GPIb-V-IX to VWF is important for platelets to initiate hemostasis. It is not known whether hemizygosity for the gene encoding GPIbβ increases the risk for bleeding following cardiac surgery for patients with 22q11.2 DS.

Methods: We performed a case-control study of 91 pediatric patients who underwent cardiac surgery with cardiopulmonary bypass from 2004 to 2012 at Children's Hospital of Wisconsin.

Results: Patients with 22q11.2 DS had larger platelets and lower platelet counts, bled more excessively, and received more transfusion support with packed red blood cells in the early postoperative period relative to control patients.

Conclusion: Presurgical genetic testing for 22q11.2 DS may help to identify a subset of pediatric cardiac surgery patients who are at increased risk for excessive bleeding and who may require more transfusion support in the postoperative period.