One-year results from the REDUCER-I multi-center real-world clinical trial of the treatment of refractory angina with the coronary sinus Reducer

Abstract Background/Introduction Patients with refractory angina have chronic symptoms due to reversible ischemia which are inadequately controlled with optimal medical therapy or interventional treatments. These patients suffer from a poor quality of life and place a significant strain on the health care system due to their frequent rehospitalizations. The coronary sinus (CS) Reducer is a stainless-steel hour-glass shaped mesh stent that creates a focal narrowing in the lumen of the CS resulting in improved microvascular resistance and redistribution of myocardial blood flow. Purpose The COSIRA randomized controlled trial showed the Reducer is a safe and effective treatment for refractory angina with patients having significant improvements in Canadian Cardiovascular Society (CCS) class and other measures of quality of life. The REDUCER-I post-market study evaluated the long-term outcomes with the Reducer in a large and challenging ‘real-world’ cohort. Methods REDUCER-I is a multicenter, non-randomized study conducted across 26 medical centers in Europe. At one year, device effectiveness was assessed by improvement in CCS grade as compared to baseline and device safety was assessed by Major Adverse Cardiac Events (MACE). Secondary endpoints included six-minute walk tests, EQ-5D-5L tests, and Seattle Angina Questionnaires (SAQ). Subjects were followed at 30 days, 6 months, and annually through five years. Results The as-treated population includes a total of 371 patients who received a Reducer implant (78.7% (292/371) male, 47.2% (175/371) diabetic, 73.9% (274/371) post-revascularization). The one-year Kaplan-Meier overall MACE rate post-implant was 7.1% (95% CI [4.9, 10.4]). There were nine deaths within the first 365 days, one death was due to unknown causes and eight deaths were adjudicated to as not being device- or procedure-related. At 12 months, 70.0% (205/293) of patients improved by ≥1 CCS class. At baseline, 72.2% (232/363) of patients were CCS class III/IV and this proportion decreased to 18.1% (54/298) at 12 months (P<0.0001). The patients’ baseline six-minute walk distance was 327.5±116.1m which improved by a mean of 30.8±81.8m at 12 months (p<.0001). In the year prior to Reducer implant, 33.3% (88/264) of the patients had at least one visit to the emergency department compared to 11.7% (31/264) in the year after Reducer implant (p<.0001). The significant improvements in CCS class and SAQ-QoL were sustained through 3 years (Figure). Conclusion In this 12-month analysis of the REDUCER-I study, patients with refractory angina treated with the CS Reducer had low MACE rates and showed significant and sustained improvements in angina, QoL, functional capacity, and need for rehospitalization.