A Comparison of Beating Heart and Arrested Heart Techniques for Mitral Valve Replacement Surgery

Introduction There is growing interest in beating heart cardiac surgery (mainly myocardial revascularization) without aortic cross-clamping and, if possible, without the use of a cardiopulmonary bypass (CPB) pump, since better results can be obtained with this procedure than with conventional myocardial protection techniques using cardioplegic solutions. This led us to considerer mitrel valve replacement (MVR) with beating heart and continuous coronary perfusion as a surgical option at the Cardiology and Cardiovascular Surgery Institute (ICCCV) in Havana, Cuba. Objective To assess the safety and potential benefits of beating heart MVR with continuous coronary perfusion compared to the conventional cardioplegic arrested heart MVR procedure. Methods A randomized, controlled intervention study was conducted with a sample of 64 patients referred to the ICCCV for isolated MVR between January 2001 and December 2002. Patients were randomly divided into 2 groups: control group A and study group B. Each group received a specific myocardial protection technique during surgery. Group A underwent MVR using the arrested heart technique with administration of a cold crystalloid cardioplegic solution and with moderately hypothermic CPB. Group B underwent MVR using the beating heart technique with normothermic CPB and continuous coronary perfusion. The following variables were assessed: serum enzyme (CK and CK-MB) and lactate concentrations; duration of aortic cross clamping, CPB, mechanical ventilation support, drainage, postoperative bleeding, stay in the surgical intensive care unit (SICU), and total operation time; amount of blood lost, blood adminstered, and postoperative complications. Quantitative variables were determined using Wilcoxon-Mann-Whitney and Student's t-tests. Results Differences between the two techniques were not found to be statistically significant, which suggests that both are equally safe. However, the differences found are clinically important and favor the beating heart technique, since patients who underwent beating heart MVR had lower serum concentrations of total CK, CK-MB and lactate; less total blood loss, and less need for transfusion. They also required less time on mechanical ventilation support in the SICU, spent fewer days in the hospital, and presented fewer postoperative complications compared to patients who underwent arrested heart MVR. Conclusion The beating heart technique with continuous coronary perfusion proved to be as safe as the conventional arrested heart technique with cardioplegic solutions for MVR surgery in patients with low surgical risk. This procedure is recommended as an alternative method of myocardial protection for this type of surgery in Cuba and may be considered as an option in other limited-resource settings.