[Comparison of effects of aprotinin and tranexamic acid on blood loss in heart surgery].

Objectives: To compare the efficacy of aprotinin (APR) and tranexamic acid (TRA) in reducing blood loss and transfusion requirements after cardiac surgery under extracorporeal circulation (ECC).

Study Design: Randomized controlled trial.

Patients: One hundred and four adults undergoing either coronary artery bypass grafting (CABG) (n = 55), or aortic valve replacement (AVR) (n = 49), allocated into three groups.

Methods: a) APR group (23 CABG and 20 AVR) received aprotinin, 2 x 10(6) KIU (280 mg) after induction, followed by an infusion of 0.5 x 106 KIU.h-1 (70 mg.h-1) until chest closure, with a supplement to the oxygenator prime of 2 x 10(6) KIU; b) TRA group (22 CABG and 19 AVR) received tranexamic acid, 15 mg.kg-1 between the injection of heparin (400 IU.kg-1) and the beginning of ECC, 15 mg.kg-1 after protamin injection (1.3 mg/100 IU of heparin); c) CTR group (10 CABG and 10 AVR), the control group, was not treated with an antifibrinolytic agent. The amount of blood collected from the chest tube drainage was measured at admission to ICU, as well as 4, 8 and 18 h after the insertion of drains and at the time of their removal. Packed red cells where given when the haematocrit was under 20% during ECC, 25% at the end of surgery and 30% after extubation.

Results: The blood loss was lower in APR group (834 +/- 448 mL) than in TRA group (1015 +/- 409 mL) (P = 0.009), and in CTR group (1416 +/- 559 ML) (P = 0.004). The rates of transfused patients in groups APR, ATR and CTR were 35, 37 and 60% respectively and the numbers of units administered per patient were 0.8, 0.8 and 1.7 respectively. In AVR cases, APR and TRA had a similar efficacy. In CABG cases, only aprotinin decreased postoperative bleeding. However there was no difference between APR and TRA concerning the transfusion requirements. In CABG cases the ECC was of shorter duration and blood loss was 1127 +/- 540 mL vs 894 +/- 422 mL in AVR cases (P = 0.03).

Conclusions: Both APR and TRA decrease blood loss. APR is more efficient after CABG than TRA as far as blood loss is concerned, whereas the transfusion requirements are similar. As APR is about 100 times more expensive and carries a risk for allergic reactions, its use in a high dose regimen is only recommended for reoperations, in patients treated with salicylates and in case of sepsis.