Effectiveness of Coronary Sinus Reducer for Treatment of Refractory Angina: A Meta-analysis

Background: Refractory angina is a debilitating condition that affects the quality of life of patients worldwide, who after exhausting standard available therapies are regarded as "no option " patients. Recently, CS (coronary sinus) reducer (Neovasc Reducer) implantation became available and is gaining popularity in the treatment of refractory angina. The effectiveness of this therapy was demonstrated in 1 randomised sham-control trial and numerous uncontrolled prospective studies entailing several hundred patients altogether. We performed a meta-analysis to incorporate the data and elucidate its efficacy and safety. Methods: A meta-analysis of prospective studies assessing the effects of CS narrowing published in English to June 2021 was performed. The primary outcome was the proportion of patients improving >= 1 class in the Canadian Cardiovascular Society (CCS) angina score. Other end points included proportion of patients improving >= 2 CCS classes, procedural success, periprocedural complications, changes in Seattle Angina Questionnaire (SAQ) scores, and 6-minute walk test (6MWT). Results: Data from 9 studies including 846 patients were included. An improvement of >= 1 CCS class occurred in 76% (95% confidence interval [CI] 73%-80%) of patients. Improvement of >= 2 CCS classes was observed in 40% of patients (95% CI 35%-46%). Procedure success was 98%, with no major and 3% nonmajor periprocedural complications. Post procedural SAQ scores and 6MWT distance were significantly improved. Conclusions: In patients suffering from angina refractory to medical and interventional therapies, Reducer implantation improves symptoms and quality of life with a low complication rate. These results are consistent in 1 randomised trial and multiple prospective uncontrolled studies.