Minimally invasive closed circuit versus standard extracorporeal circulation for aortic valve replacement.

BACKGROUND: The purpose of this study was to evaluate the safety and clinical results of aortic valve replacement performed with minimally invasive closed circuit extracorporeal circulation technique (MECC system) versus standard cardiopulmonary bypass.

METHODS: Forty consecutive patients undergoing isolated aortic valve replacement at a single institution were randomly assigned to either miniaturized closed circuit cardiopulmonary bypass with the Maquet-Cardiopulmonary (Rastatt, Germany) minimal extracorporeal circulation (MECC) system (study group B, n = 17) or standard cardiopulmonary bypass (control group A, n = 23). The MECC system is a low priming circuit without blood-air interface. Technical feasibility, in particular the potential entry of air in the circuit, and clinical results were prospectively evaluated.

RESULTS: Demographic characteristics and surgical data were similar in both groups. Patients in the study group showed reduced chest tube drainage (217 +/- 62 mL vs 420 +/- 219 mL, p < 0.05) and blood transfusion requirements (5.1% vs 43.4%, p < 0.02) compared with patients in the control group. Moreover, the study group showed significantly higher time course of hematocrit at all time points during the operation and longer hospital stay (p < 0.02) than the control group; similarly, in the study group patients' platelet count in intensive care unit admission was significantly higher than the control group (140 +/- 29 x 10(9)/L vs 119 +/- 37 x 10(9)/L, p < 0.05). Peak postoperative troponin C release was significantly lower in the study group (4.74 +/- 2.82 vs 8.43 +/- 6.25 ng/dL, p < 0.033). One patient undergoing the MECC system operation showed a major neurologic event on postoperative day four, which was probably secondary to severe aortic calcification.

CONCLUSIONS: The MECC system is suitable for aortic valve replacement and provides better clinical results than standard cardiopulmonary bypass as regards blood transfusion requirements, platelets consumption, and myocardial damage.