Coagulation in Acute Aortic Dissection

Hypotheses: Primary: HDR-approach is superior to ACT-approach in terms of suppressing thrombin generation after emergent surgery for acute aortic dissection (Stanford type A). Secondary: HDR-approach is superior with regard to * early postoperative haemostatic capacity * requirement of blood product transfusion and haemostatic agents * postoperative bleeding Design: Investigator-initiated, single-site, parallel-group (1:1), prospective, randomized, partially double-blinded trial in patients undergoing emergent surgery for acute aortic dissection comparing two heparin management strategies with superiority design. Prior to randomization, patients are stratified according to preoperative organ dysfunction and anticoagulation therapy. Acute research study design as patients with acute aortic dissection are considered incompetent according to the Danish Research Ethics Committees definition. Deferred consent by the competent patient or her/his proxy (next of kin) and an independent physician) is used. 26 consecutive patients undergoing emergent surgery for acute aortic dissection (Stanford type A) are randomized 1:1 into the following heparin management strategies with an ACT target of 480 seconds: * Individualised HDR-approach * Conventional ACT-approach No interim analysis. A sub-study to compare cost-benefit of both strategies is planned.