Stroke after cardiac surgery: a retrospective analysis of the effect of aprotinin dosing regimens

Half-dose aprotinin (HDA) appears to be equivalent to full-dose aprotinin (FDA) in its ability to prevent bleeding. However, data regarding the potential effect of aprotinin use and dosage on other outcomes such as the occurrence of perioperative stroke are limited. It has been postulated that the higher level of kallikrein inhibition obtained with FDA dosing may be required for end-organ protection. Therefore, we performed a retrospective study in cardiac surgery patients at high risk for developing stroke to determine the relative effects of FDA and HDA regimens on the incidence of postoperative stroke. Records of 1,524 patients undergoing cardiac surgery over a 15-month period were reviewed. Patients at high risk for stroke were selected if they met all of the following predefined criteria: age greater than 70 years, history of hypertension, history of diabetes mellitus, history of stroke or transient ischemic attack, and presence of aortic atheroma. A validated preoperative stroke risk index was calculated for each patient. Postoperative stroke required confirmation by computed tomography or magnetic resonance imaging. Patients were divided into three groups according to whether they were administered no aprotinin, HAD, or FDA. A total of 149 patients fulfilled the criteria for being at high risk for stroke. Stroke risk index was very similar ( p = 0.56) in the three groups: those who received no aprotinin and served as a control group (124 ± 15, n = 56), those who were given HDA (123 ± 12, n = 67), and those who received FDA (122 ± 11 n = 26). Preoperative and intraoperative characteristics were also similar between the three study groups. Overall, the incidence of stroke was 16% (24/149). The incidence of stroke differed ( p < 0.05) among the three groups: no aprotinin 16% (9/56), HDA 22% (15/67), and FDA 0% (0/26). In this retrospective study of cardiac surgery patients at high risk for postoperative stroke, the administration of FDA but not HDA was associated with a lower incidence of stroke.