Effects of aprotinin administration and cell-saver apparatus on post-operative bleeding and platelet function during cardiac surgery

Abstract

Cardiopulmonary bypass (CPB) causes platelet damage. Disturbances of haemostasis with bleeding is a serious complication after open heart surgery. Recently a reduction in blood loss and blood requirements during and after CPB have been achieved by prophylactic treatment with the proteinase inhibitor aprotinin [1]. The mechanism of action of aprotinin is still controversial. The haemostatic effect of aprotinin is attributed to the protection of platelet inhibition of the intrinsic clotting system or prevention of hyperfibrinolysis [2,3]. The cell-saver apparatus (CSA), is a simple and safe centrifugal type of blood concentrator. This method efficiently excludes free haemoglobin and reduces homologous blood transfusion [4]. The aim of this study is to assess the effect of aprotinin administration and CSA on coronary artery bypass surgery (CABG). The study protocol was approved by the Ethical Committee. A standard anaesthetic technique was used. Forty-five patients undergoing elective CABG were studied. Fifteen patients served as controls (Group 1). For the other fifteen patients CSA was used (Dideco-Shiley) (Group 2). In Group 3 fifteen patients were assigned to both aprotinin treatment and CSA during the operation. Aprotinin (Trasylol) 35×103IU kg−1 was given over a 30 min period after the induction and 2×106 IU aprotinin was administered in the CPB priming volume. Thereafter a continuous infusion of 0.5×106 IU kg−1 was administered until the end of the operation. Intra-operative blood loss was determined by weighing sponges, measuring suction drainage. Post-operative blood loss was measured from chest-tube drainage. Platelet aggregation was measured using an Aggrecorder 2 PA 3220. Aggregation was induced by adenosine diphosphate (ADP), collagen and ristocetin. All measurements were made preoperatively, in the early post-operative period (ICU) and on the first day after operation. The platelet aggregation values were calculated as a percentage. The difference between values were evaluated for statistical significance with one-way analysis of variance (ANOVA). P-values less than 0.05 were considered to be significant. There were no differences between the groups with respect to age, body weight, CPB times and fluid balance. Changes in platelet aggregation variables are illustrated in Table 7. Platelet aggregation was significantly higher in Group 2 and Group 3 (P<0.001).Table 7: (abstract 22). Post-operative Platelet Aggregation (P<0.001) Intra-operative blood loss after CPB was significantly reduced in Group 2 and Group 3 (P<0.05). Post-operative blood loss was also significantly reduced in Group 2 and Group 3 (P<0.05) Table 8.Table 8: (abstract 22). Intra-operative and post-operative blood loss (mL) (P<0.05) We conclude that aprotinin infusion and CSA has important platelet-preserving effects during CPB, thus leading to a better haemostatic mechanism and consequently reducing post-operative blood loss and blood requirement.