The efficacy of coronary sinus reducer in patients with refractory angina-A systematic review of the literature

Objectives: The aim of our systematic review was to investigate the efficacy of coronary sinus (CS) reducer device in patients with refractory angina.

Background: The CS reducer device provides a therapeutic option for patients with coronary artery disease who are not suitable for revascularization.

Methods: Two independent investigators (GB and GT) systematically searched the Medline and Cochrane library databases for studies describing the efficacy and safety of the CS reducer in patients with refractory angina from January 1, 2000 until May 12, 2018 using the following terms: "coronary sinus (reducer OR reducing) device." Efficacy was defined as ≥1 unit improvement in the Canadian cardiovascular society (CCS) score.

Results: Our search strategy provided six studies (five observational studies and one randomized clinical trial) with 196 patients. The CS reducer device was effective in 146/186 (78.5%) patients. CCS score improved from 3.2 at baseline to 1.9 after 8.6 months of follow-up. The efficacy of CS reducer device was also demonstrated as an improvement in Seattle Angina Questionnaire score, dobutamine echocardiography, thalium single-photon emission computed tomography perfusion studies, 6-min-walk test and myocardial perfusion reserve index. Implantation failed in 4 of 196 (2%) patients and 5 patients (2.5%) had a complication during 30-day follow-up.

Conclusions: The CS reducer is a promising treatment option for patients with refractory angina who are not candidates for revascularization. However, larger randomized control trials with long-term follow-up are needed to elucidate its role.