Remote Ischemic Conditioning: A Clinical Trial's Update

Coronary artery disease (CAD) is the leading cause of death and disability worldwide, and early and successful restoration of myocardial reperfusion following an ischemic event is the most effective strategy to reduce final infarct size and improve clinical outcome. This process can, however, induce further myocardial damage, namely acute myocardial ischemia-reperfusion injury (IRI) and worsen clinical outcome. Therefore, novel therapeutic strategies are required to protect the myocardium against IRI in patients with CAD. In this regard, the endogenous cardioprotective phenomenon of "ischemic conditioning," in which the heart is put into a protected state by subjecting it to one or more brief nonlethal episodes of ischemia and reperfusion, has the potential to attenuate myocardial injury during acute IRI. Intriguingly, the heart can be protected in this manner by applying the "ischemic conditioning" stimulus to an organ or tissue remote from the heart (termed remote ischemic conditioning or RIC). Furthermore, the discovery that RIC can be noninvasively applied using a blood pressure cuff on the upper arm to induce brief episodes of nonlethal ischemia and reperfusion in the forearm has greatly facilitated the translation of RIC into the clinical arena. Several recently published proof-of-concept clinical studies have reported encouraging results with RIC, and large multicenter randomized clinical trials are now underway to investigate whether this simple noninvasive and virtually cost-free intervention has the potential to improve clinical outcomes in patients with CAD. In this review article, we provide an update of recently published and ongoing clinical trials in the field of RIC.