An increasing number of patients have angina that is refractory to maximal medical therapy and unable to be addressed with revascularization procedures. Prior small studies have suggested the promise of generating a pressure gradient upstream of the myocardial venous drainage system to relieve angina. This can be accomplished through the percutaneous implantation of a device that reduces the orifice for coronary sinus blood flow. The Coronary Sinus Reducer for Treatment of Refractory Angina (COSIRA) trial randomized 104 patients with Canadian Cardiovascular Society (CCS) class III or IV angina, evidence of myocardial ischemia, and no remaining revascularization options to percutaneous implantation of a coronary sinus reducing device or a sham procedure in a double blind fashion. At six months of follow-up, an improvement in at least 2 classes of CCS angina severity was noted with device implantation in 35% vs. 15% of sham controls (P=0.02). An even higher proportion experienced improvements of at least 1 CCS class (71% vs. 42, P=0.003) and quality of life indices also favored the device group (P=0.03). There were no differences in rates of adverse events between the two groups.
This small study demonstrates the potential for a device implanted in the coronary sinus to improve angina and quality of life among patients with refractory angina. Larger trials are now needed to fully inform the potential risks and benefits of this novel invasive approach to improve angina symptom burden.
Summarized by Hussain Contractor and Steven M. Bradley
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