-Review-

Future Perspective of Cardioplegic Protection in Cardiac Surgery

Yuji Maruyama^1,2, David J Chambers³ and Masami Ochi^1,2

¹Department of Cardiovascular Surgery, Graduate School of Medicine, Nippon Medical School
²Department of Cardiovascular Surgery, Nippon Medical School
³Cardiac Surgical Research/Cardiothoracic Surgery, The Rayne Institute (King's College London), Guy's and St Thomas' Hospital NHS Foundation Trust, St Thomas' Hospital

"Depolarized arrest", induced by hyperkalemic (moderately increased extracellular potassium) cardioplegia is the gold standard to achieve elective temporary cardiac arrest in cardiac surgery. Hyperkalemic cardioplegic solutions provide good myocardial protection, which is relatively safe and easily and rapidly reversible. However, this technique has detrimental effects associated with ionic imbalance involving sodium and calcium overload of the cardiac cell induced by depolarization of the cell membrane. Hence, the development of an improved cardioplegic solution that enhances myocardial protection would be expected as an alternative to hyperkalemic cardioplegia. In this review, we assess the potential disadvantages of "depolarized arrest" and the suitability and clinical potential of "non-depolarized arrest". "Magnesium cardioplegia" and "esmolol cardioplegia" has been shown to exert superior protection with comparable safety profiles to that of hyperkalemic cardioplegia. These alternative techniques require further examination and investigation to challenge the traditional view that hyperkalemic arrest is best.
Endogenous cardioprotective strategies, termed "ischemic preconditioning" and "ischemic postconditioning", may have a role in cardiac surgery to provide additional protection. The elective nature of cardiac surgery, with the known onset of ischemia and reperfusion, lends it to the potential of these strategies. However, the benefit of preconditioning and postconditioning during cardiac surgery is controversial, particularly in the context of cardioplegia. The clinical application of these strategies is unlikely to become routine during cardiac surgery because of the necessity for repeated aortic crossclamping with consequent potential for embolic events, but offers considerable potential especially if "pharmacological" preconditioning and postconditioning could be established.

J Nippon Med Sch 2013; 80: 328-341

Keywords
cardioplegia, magnesium, esmolol, ischemic preconditioning, ischemic postconditioning

Correspondence to
Yuji Maruyama, MD, Department of Cardiovascular Surgery, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan
maruyamayuji@nms.ac.jp

Received, February 3, 2013
Accepted, March 25, 2013