Coronary Sinus Reduction for REDUCER-I Patients With Refractory Angina and Angiographically Nonobstructive Coronary Artery Disease

AbstractBackgroundPatients with angiographically nonobstructive coronary artery disease (CAD) (AngioNOCAD), including those with previous successful revascularization, often experience refractory angina (RA).ObjectivesThe objective of the study was to assess the efficacy of coronary sinus (CS) Reducer for the treatment of patients with AngioNOCAD and no further revascularization options.MethodsThe REDUCER-I registry is a nonrandomized, real-world observational study of patients with RA, objective evidence of ischemia on noninvasive stress testing, and with no further revascularization options. AngioNOCAD was defined as < 70% stenosis by visual adjudication in all major epicardial coronary arteries at time of enrollment. 12-month outcomes included Canadian Cardiovascular Society class, Seattle Angina Questionnaires (SAQ), and major adverse events.ResultsOf the 371 patients who received a CS Reducer implant, 306 reported baseline CAD type, 61/306 (19.9%) had AngioNOCAD, and 245/306 (80.1%) had obstructive CAD. Both groups had similar baseline characteristics although the AngioNOCAD patients were younger (65.8 ± 11.3 years vs 70.2 ± 8.7 years), had less prior coronary artery bypass grafting (44.3% vs 79.6%), and more prior percutaneous coronary intervention (44.3% vs 71.8%) than patients with obstructive CAD. Twelve months after CS Reducer implantation, 60.3% of the AngioNOCAD cohort and 71.7% of the obstructive CAD cohort had ≥1 Canadian Cardiovascular Society class improvement (P = 0.11). Twelve-month MACE rates were similar (AngioNOCAD 7.0%, obstructive CAD 8.0%), and both groups had significant improvements in SAQ angina frequency, quality of life, and mean SAQ summary score (P < 0.01).ConclusionsIn the REDUCER-I registry, patients with RA and AngioNOCAD had significant improvements in their symptoms and quality of life suggesting that CS Reducer implantation may be an effective therapy in these patients.