ENHANCED BLOOD CONSERVATION AND IMPROVED CLINICAL OUTCOME AFTER VALVESURGERY USING HEPARIN-BONDED CARDIOPULMONARY BYPASS CIRCUITS

Background: Recently, heparin-bonded (HBC) cardiopulmonary bypass circ uits (CPB) were formed to be associated with improved outcome after co ronary artery bypass grafting. There are very few reports on the effic acy and safety of these circuits in valve surgery. Methods: A retrospe ctive cohort study of all patient populations undergoing first time va lve surgery from 1992 to 1995 in a tertiary teaching hospital. Outcome s of 120 patients undergoing valve surgery using HBC and lower anticoa gulation HBC were compared to 232 patients treated with conventional c ircuits and full heparinization (nonheparin-bonded-circuit [NHBC]). Re sults: Postoperative 24-hour chest tube drainage (558 +/- 466 mL vs 10 54 +/- 911 mL, p < 0.00001), and reoperation for bleeding (2.5% vs 8.2 %, p = 0.04) were lower in the HBC group. HBC patients required signif icantly less transfusions (total donor exposure of 6.9 +/- 13.0 units vs 18.6 +/- 26.2 units, p < 0.00001). Multiple linear regression analy sis identified CPB time as a predictor of increased homologous blood t ransfusions, and the use of HBC, a large body surface area, and electi ve procedure as predictors of decreased transfusions. Perioperative mo rtality was similar (HBC 2.5%, NHBC 4.7%, p = 0.24). Overall complicat ions were lower in the HBC group (42% vs 56.2%, p = 0.02). Perioperati ve myocardial infarction (0.8% vs 1.3%, p = 0.58) and cerebrovascular accident (3.3% vs 3.9%, p = 0.53) were similar. Two (1.7%) HBC patient s had valve re-replacement compared to none in the NHBC (p = 0.22). Mu ltiple logistic regression model revealed that age and CPB time were a ssociated with increased complications, and the use of HBC with reduce d complications. Conclusion: Use of HBCs with lower anticoagulation in valve surgery resulted in a significant reduction of transfusion requ irements and improved clinical outcome. Because of a potential for ear ly mechanical valve thrombosis, until further data is available, conve ntional levels of systemic anticoagulation should be achieved when usi ng HBC in valve surgery.