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

## TL;DR

This study shows that implanting a coronary sinus Reducer improves symptoms and quality of life in patients with refractory angina and nonobstructive coronary artery disease.

## Contribution

Demonstrates the effectiveness of CS Reducer in AngioNOCAD patients with refractory angina, a previously understudied group.

## Key findings

- 60.3% of AngioNOCAD patients improved in Canadian Cardiovascular Society class after 12 months.
- Both AngioNOCAD and obstructive CAD groups showed significant improvements in SAQ scores.
- MACE rates were similar between AngioNOCAD and obstructive CAD patients.

## Abstract

Patients with angiographically nonobstructive coronary artery disease (CAD) (AngioNOCAD), including those with previous successful revascularization, often experience refractory angina (RA).

The 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.

The 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.

Of 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).

In 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.