Coagulation in Acute Aortic Dissection

Acute aortic dissection (AAD) involving the ascending aorta (Stanford classification type A) remains a life-threatening disease. Excessive perioperative bleeding requiring massive transfusion of allogeneic blood products, and surgical reexploration remain major challenges in these patients. Previous research has indicated that patients with AAD show pronounced haemostatic alterations prior to surgery which are aggravated during major aortic surgery with cardiopulmonary bypass and hypothermia full heparinization. Intensified anticoagulation management guided by heparin dose response (HDR) calculation, and repeated measurement of heparin concentration may be more effective than standard empiric weight-based heparin and protamine management monitored by activated clotting time (ACT) measurements to suppress thrombin generation during surgery for AAD. This randomized controlled clinical trial compares the impact of two recommended anticoagulation management strategies during surgery for AAD including deep hypothermia on activation of coagulation: Heparin/protamine-management based on HDR-titration by means of HMS Plus® versus current institutional standard (HDR- versus ACT-approach). Primary endpoint is thrombin generation as measured by early postoperative prothrombin fragment 1+2 (F1+2). Secondary endpoints are other markers of coagulation and fibrinolysis as well as clinical outcome.