Safety and efficacy of coronary sinus narrowing for treating refractory angina in real-world setting - single center experience

Introduction Refractory angina affects patients who remain symptomatic despite optimal medical therapy and for whom further revascularization is not feasible. Therapeutic options for this population are limited. The coronary sinus reducer (CSR) has emerged as a device-based treatment aimed at improving symptoms and functional capacity in this patient group. Evidence is growing, but real-world data remain scarce. Purpose To investigate whether Coronary Sinus Reducer (CSR) implantation is safe and efficient in a real-world cohort of patients presenting with refractory angina. Methods Twenty-six consecutive patients diagnosed with refractory angina, objective evidence of myocardial ischemia, despite receiving optimal medical therapy, in whom further revascularization was not feasible, were treated with CSR at our Institution between September 2023 and October 2025. The study endpoints, assesed at baseline and 3-months, were defined as changes in angina severity (Canadian Cardiovascular Society [CCS] class, the 7-item Seattle Angina Questionnaire [SAQ-7]), exercise tolerance (6-minute walking distance [6MWD]) and a change in pharmacological antianginal therapy together with safety outcomes (procedural success and complications). Results A total of 87,5% of the patients presented a reduction in angina severity reflected by a downgrade of at least one CCS class (P < 0.0001) over the 3 months of follow up, as compared with the baseline. Angina control, quantified by the SAQ-7 summary score, improved from a mean (SD) of 15.95 (15.32) at baseline to 55.38 (27.74) at 3 months (P < 0.0001). A similar pattern was observed in individual SAQ-7 domains. Physical limitation improved from 4.60 (2.68) to 10.08 (3.67) (P < 0.0001), angina frequency decreased from 4.68 (2.04) to 8.72 (2.23) (P < 0.0001), and quality-of-life scores rose from 3.20 (1.38) to 6.88 (2.52) (P < 0.0001). The number of antianginal medications declined from a median of 3 (IQR 2–4) at baseline to 2 (IQR 1–3) at 3 months (P = 0.0046). The median 6-minute walk distance increased from 300 m (IQR 180-420) at baseline to 375 m (IQR 240-450) after 3 months (P = 0.0313). Procedural success was achieved in all patients, with no device related complications. Conclusions In this real-world, single-center experience, implantation of Coronary Sinus Reducer was safe and associated with marked improvements in symptom burden, quality of life, and functional capacity after 3 months. The procedure led to a significant reduction in CCS class, higher SAQ-7 scores across all domains, improved exercise tolerance, and decreased reliance on antianginal medication. These findings support the clinical benefit of the coronary sinus reducer as a safe and effective therapeutic option in patients with refractory angina unsuitable for revascularization.