Beating heart continuous coronary perfusion for valve surgery: what next for clinical trials?

Aortic root replacement in severe left ventricular dysfunction: The added value of beating-heart surgery

There are limits to the use of cardioplegic arrest during complex cardiac surgical procedures, especially in patients with severe left ventricular dysfunction. In the current report, we graphically present the detailed surgical strategy and technique for beating-heart aortic root replacement with concomitant coronary bypass grafting, for patients otherwise deemed inoperable. With support of cardiopulmonary bypass (CPB), beating-heart bypass surgery is realized, after which the bypass grafts can selectively be connected to the CPB, preserving coronary flow. Then, on the beating and perfused heart, a complex procedure such as aortic root replacement can be performed, without jeopardizing postoperative cardiac function. However, several important caveats and remarks regarding the use of beating-heart surgery should be considered, including: coronary perfusion verification and maintenance, temperature management, and prevention of air embolisms. By use of this strategy, risks associated with cardioplegic arrest are minimized, while it circumvents the potential need for long-term postoperative extracorporeal membrane oxygenation.

Cardioplegic strategies to protect the hypertrophic heart during cardiac surgery

Cardioplegic arrest and cardiopulmonary bypass are key triggers of myocardial injury during aortic valve surgery. Cardioplegic ischaemic arrest is associated with disruption to metabolic and ionic homeostasis in cardiomyocytes. These changes predispose the heart to reperfusion injury caused by elevated intracellular reactive oxygen species and calcium. Cardiopulmonary bypass is associated with an inflammatory response that can generate systemic oxidative stress which, in turn, provokes further damage to the heart. Techniques of myocardial protection are routinely applied to all hearts, irrespective of their pathology, although different cardiomypathies respond differently to ischaemia and reperfusion injury. In particular, the efficacy of cardioprotective interventions used to protect the hypertrophic heart in patients with aortic valve disease remains controversial. This review will describe key cellular changes in hypertrophy, response to ischaemia and reperfusion and cardioplegic arrest and highlight the importance of optimising cardioprotective strategies to suit hypertrophic hearts.