Myocardial ischemic conditioning: Physiological aspects and clinical applications in cardiac surgery

Abstract

Ischemia-reperfusion is a major determinant of myocardial impairment in patients undergoing cardiac surgery. The main goal of research in cardioprotection is to develop effective techniques to avoid ischemia-reperfusion lesions. Myocardial ischemic conditioning is a powerful endogenous cardioprotective phenomenon. First described in animals in 1986, myocardial ischemic conditioning consists of applying increased tolerance of the myocardium to sustained ischemia by exposing it to brief episodes of ischemia-reperfusion. Several studies have sought to demonstrate its effective cardioprotective action in humans and to understand its underlying mechanisms. Myocardial ischemic conditioning has two forms: ischemic preconditioning (IPC) when the conditioning stimulus is applied before the index ischemia and ischemic postconditioning when the conditioning stimulus is applied after it. The cardioprotective action of ischemic conditioning was reproduced by applying the ischemia-reperfusion stimulus to organs remote from the heart. This non-invasive manner of applying ischemic conditioning has led to its application in clinical settings. Clinical trials for the different forms of ischemic conditioning were mainly developed in cardiac surgery. Many studies suggest that this phenomenon can represent an interesting adjuvant to classical cardioprotection during on-pump cardiac surgery. Ischemic conditioning was also tested in interventional cardiology with interesting results. Finally, advances made in the understanding of mechanisms that underlie the cardioprotective action of ischemic conditioning have paved the way to a new form of myocardial conditioning which is pharmacological conditioning.

Remote ischemic preconditioning versus intermittent hypoxia training: a comparative analysis for cardioprotection

“…IPC involves several factors that are usually divided into three groups: triggers, mediators, and effectors [18][19][20]. The signaling pathways are complex and not yet fully understood.…”

“…Potential mechanisms of RIPC are good described in recent reviews [20,33]. Authors consider that despite the uncertainty in fundamental RIPC mechanisms, they can be divided into three main components: (1) humoral, (2) neural, and (3) systemic factors of cardioprotection.…”

“…According to Bousselmi et al [20], the first clinical trial in humans was negative [60]. Later on Cheung et al [61] randomized 37 children scheduled for surgical repair of congenital heart defects.…”

A pilot study of perioperative esmolol for myocardial protection during on-pump cardiac surgery

“…Perioperative myocardial injury remains one of the most serious complications of cardiac surgery (1–3), and numerous factors have been implicated during the pathogenesis process, including the technique of cardiac surgery, induction of cardioplegia and period of cardiac arrest (4–6). The primary mechanisms underlying myocardial dysfunction in this process are ischemic-reperfusion injury and the associated inflammatory responses (6–9).…”

The Protective Effects of Myocardial Ischemic Postconditioning on Cardiac Surgry: A Systematic Review and Meta-Analysis of Rats and Clinical Trials

“…But clamping/decamping the ascending aorta was lined with a high risk of embolic accidents, especially in adults with atherosclerotic lesions of the aortic wall. It is the reason for paucity of clinical trials in cardiac surgery, perhaps (56).…”