REducing Microvascular Dysfunction in patients with angina, ischaemia and unobstructED coronarY arteries, a PILOT study (REMEDY-PILOT)

REMEDY-PILOT

Patient / Population Intervention / Exposure Comparison Outcome

In patients with refractory angina, no obstructive coronary artery disease and coronary microvascular dysfunction, coronary sinus reducer implantation did not improve segmental endocardial myocardial perfusion reserve or angina frequency at 6 months compared with a sham procedure.

N

54patients

Design

Single-centre (Imperial College London), double-blind, sham-controlled randomised pilot trial of coronary sinus reducer implantation in refractory angina with coronary microvascular dysfunction and unobstructed coronary arteries

Endpoint

Feasibility (consent and withdrawal rates) and change in myocardial perfusion at 6 months

ResultAt 6 months there was no difference between the reducer and sham arms in the change in segmental endocardial myocardial perfusion reserve (P = 0.72). The ratio of endocardial to epicardial myocardial blood flow during stress was also unaffected (P = 0.88). Patient-reported daily angina episodes improved in both groups with no significant difference between the reducer and sham arms (OR 0.92; 95% credible interval 0.42-2.04); the probability of benefit was 0.41. The reducer did not have a significant impact on the Seattle Angina Questionnaire summary score. There was one device-related serious adverse event (tamponade).

Cheng K, et al. Presented at TCT 2026, 1 November. Reported by TCTMD (CRF). Not yet published.

Discussion & critique

This randomised, double-blind, sham-controlled pilot showed that the reducer could be implanted safely, with one device-related tamponade, but it did not improve myocardial perfusion, angina frequency or Seattle Angina Questionnaire scores compared with sham at 6 months. Angina improved in both arms, which the presenter attributed to a large placebo effect, and this shows why a sham comparator matters in this setting. With 54 patients at a single centre and a perfusion surrogate as the primary endpoint, the trial was small and designed to test feasibility, so it cannot exclude a modest clinical benefit or assess hard outcomes. The report says the device seemed to improve CCS angina grade but gives no figures for it, and it does not report feasibility measures such as consent or withdrawal rates.