Implantation of a device to narrow the coronary sinus and increase myocardial venous pressure was compared with a sham procedure in patients with refractory angina. The proportion of patients with improvement at 6 months was significantly greater with the device. A growing number of patients with severe and diffuse obstructive coronary artery disease who are not candidates for revascularization have debilitating angina despite medical therapy. 1 – 3 The worldwide prevalence of refractory angina is increasing, and new therapeutic options are needed. 4 An endoluminal, balloon-expandable, stainless steel, hourglass-shaped device designed for percutaneous implantation in the coronary sinus (Reducer, Neovasc) creates a focal narrowing that leads to increased pressure in the coronary sinus, which may relieve angina (Figure 1). A nonrandomized first-in-human study involving 15 patients with refractory angina who were treated with the device showed significant improvement with respect to angina class. . . .