The novel synthetic serine protease inhibitor CU-2010 dose-dependently reduces postoperative blood loss and improves postischemic recovery after cardiac surgery in a canine model

Background: Serine protease inhibitors such as aprotinin reduce perioperative blood loss and may improve post-pump cardiac performance owing to their anti-inflammatory properties. After the "aprotinin era,'' we investigated the efficacy of the novel synthetic serine protease inhibitors CU-2010 with improved coagulatory and anti-inflammatory profile on blood loss and reperfusion injury in a canine model. Methods: Thirty-six dogs were divided into 6 groups: control, aprotinin (n = 8; Hammersmith scheme), and CU-2010 (0.5, 0.83, 1.25, and 1.66 mg/kg). All animals underwent 90 minutes of cardiopulmonary bypass with 60 minutes of hypothermic cardioplegic arrest. End points were blood loss during the first 2 hours after application of protamine, as well as recovery of myocardial contractility (slope of the end-systolic pressure-volume relationship, coronary blood flow, and vascular reactivity. Results: CU-2010 dose-dependently reduced blood loss to a degree comparable with that of aprotinin at lower doses and even further improved at higher doses (control/aprotinin/CU-2010 in increasing doses: 142 +/- 13, 66 +/- 17, 95 +/- 16, 57 +/- 17, 46 +/- 3, and 13 +/- 4 mL; P < .05). Whereas aprotinin did not influence myocardial function, CU-2010 improved the recovery of end-systolic pressure-volume relationship (control 60 +/- 6 mg kg vs aprotinin 73 +/- 7 mg/kg vs CU-2010 1.66 mg/kg; 102% +/- 8%; P < .05). Coronary blood flow (52 +/- 4 vs 88 +/- 7 vs 96 +/- 7; P < .05) and response to acetylcholine (44% +/- 6% vs 77% +/- 7% vs 81% +/- 6%; P < .05) were improved by both aprotinin and CU-2010. Conclusions: The novel serine protease inhibitor CU-2010 significantly reduced blood loss after cardiac surgery comparable with aprotinin. Furthermore, an additionally improved anti-inflammatory profile led to a significantly improved postischemic recovery of myocardial and endothelial function. (J Thorac Cardiovasc Surg 2010; 139: 732-40)