Surgical Procedures
The surgical technique for ATAAD used at our center has been described
previously 17. Median sternotomy, cardiopulmonary
bypass (CPB) with hypothermic circulatory arrest and cold blood
cardioplegia was used in all cases. Heparin was reversed with protamine
after weaning from CPB and transfusion of procoagulants and blood
products initiated. The cooling strategy used in the elective controls
were hemiarch procedure 25°C; valve sparing root replacement (ad modum
David): 30°C; root replacement (ad modum Bentall) or aortic valve
replacement with supracoronary replacement of the ascending aorta: 32°C;
isolated replacement of the ascending aorta: 32-36°C.
During the study period, all patients received preoperative tranexamic
acid (2-3g preoperatively and 1-2g after termination of CPB for a total
of 4g) to prevent hyperfibrinolysis. A Dideco Electa (Sorin Group,
Electa, Italy) cell saver machine was used to process and re-infuse
salvaged blood. Heparin dose was calculated using the Hepcon HMS Plus
system (Medtronic, Minneapolis, MN, USA) to reach an activated clotting
time (ACT) of >480s and monitored serially during CPB to
maintain ACT >480s with additional heparin added if
necessary. Antithrombin was administered if the heparin dose response
slope was low (<70s/U/ml) and a subsequent test was conducted
ten minutes later. Two patients in each group received 2000IE of
antithrombin during surgery. ACT was routinely controlled at the end of
surgery, and additional protamine was given if ACT exceeded 120 seconds.