[Trimetazidine and cardioprotection during ischemia-reperfusion]

Although early reperfusion of ischemic myocardium is now considered to be the only intervention able to restore the various cellular functions altered by ischemia and to prevent progression toward cell death of myocardial cells due to necrosis or apoptosis, reperfusion is accompanied by various manifestations grouped under the heading of reperfusion damage or reperfusion syndrome. Functional recovery is therefore not immediate, but usually appears after a certain delay following a period of contractile dysfunction (myocardial stunning) lasting for several hours or even days after the start of reperfusion. The cellular mechanisms underlying the reperfusion damage may involve cellular calcium overload, over-production of oxygen-derived free radicals, cellular acidosis, inflammatory reaction, and microcirculatory dysfunction. Numerous pharmacological studies have been conducted to limit such reperfusion injury and, consequently, prevent stunning and/or reperfusion-induced arrhythmias. A number of experimental and clinical studies have demonstrated the beneficial effects of trimetazidine, a drug that inhibits the long-chain mitochondrial 3-ketoacyl coenzyme A thiolase enzyme in the myocyte, resulting in a shift from fatty acid oxidation to glucose oxidation. This optimization of cardiac metabolism results in direct anti-ischemic effects, limiting calcium accumulation and acidosis, inflammation and oxygen free radical production, and improvement of coronary microcirculation following reperfusion. This agent appears to be particularly promising clinically in the treatment of reperfusion injury, for example in combination with reperfusion strategies during the acute phase of myocardial ischemia or infarction, or in the reduction of the pro-remodeling effects of ischemia in patients with chronic ischemic syndrome and left ventricular dysfunction.