[Coronary Sinus Reducer implantation: a new treatment for chronic refractory angina]

Refractory angina is a chronic condition characterized by the presence of disabling symptoms due to severe obstructive coronary artery disease not improved by either optimal medical therapy and/or percutaneous or surgical revascularization. Mortality rates associated with this condition are quite low in clinically stable patients on optimal medical therapy. However, rehospitalization rates are high. In this subgroup of patients there is thus a clinical need for new therapies targeting an improvement of symptoms but taking into account the potential impact in terms of healthcare and costs. A considerable number of innovative therapeutic modalities for the treatment of refractory angina have been investigated over the years. However, none of them has become a standard of care. Devices implanted in coronary sinus are a possible therapeutic option in these patients that may alleviate myocardial ischemia by forcing redistribution of coronary blood flow from less ischemic subepicardium to the more ischemic subendocardium, potentially relieving symptoms of ischemia. The coronary sinus Reducer (Neovasc Inc., Richmond B.C., Canada) is a percutaneous implantable device designed to achieve controlled narrowing of the coronary sinus and to increase its upstream pressure. Coronary sinus Reducer implantation was associated with improvement in symptoms and reduction of myocardial ischemia in pre-clinical and clinical studies. Recently, a randomized, double-blind, multicenter clinical trial demonstrated, in 104 patients with refractory angina, its benefit in improving symptoms, when compared to placebo.