REMEDY-PILOT Evaluates Coronary Sinus Reducer to Treat Refractory Angina With Unobstructed Coronary Arteries 

November 1, 2026—Findings from the REMEDY-PILOT trial evaluating the efficacy and feasibility of coronary sinus reducer (CSR) implantation in patients with coronary microvascular dysfunction (CMD) and refractory angina without significant obstruction of the major coronary arteries, were presented by Kevin Cheng, MA, BMBCh, at TCT 2026.

According to the TCT press release, the procedure was safe in these patients but did not significantly improve myocardial perfusion reserve (MPR), patient-reported symptoms, or quality of life.

The press release stated that between May 2023 and February 2026, the study randomized 54 patients (24 women and 30 men) with refractory angina, unobstructed coronary arteries, and reduced MPR. Of these patients, 90% were in Canadian Cardiovascular Society (CCS) class III/IV despite taking a median of four anti-anginal medications.

After deep conscious sedation together with auditory and visual isolation, the study patients were randomized 1:1 to CSR implantation or a sham procedure, with blinded follow-up continuing for 6 months.

As summarized in the press release, Dr. Cheng reported the following at TCT 2026:

• In the primary endpoint, the change in segmental endocardial MPR after 6 months, CSR did not result in improvement, with an adjusted treatment effect of -0.03 (95% CI, -0.22 to 0.15; P = .72).
• Some key secondary endpoints were also not significantly different between groups, including endocardial to epicardial ratio at stress, which had an adjusted relative treatment effect of 1.004 (95% CI, 0.954 to 1.057; P = .88) and patient-reported number of daily angina episodes, which had an estimated odds ratio of 0.92 (95% credible interval, 0.42 to 2.04; Pr[Benefit] = .41).
• CCS class was slightly improved for those patients who received CSR (odds ratio, 0.30; 95% CI, 0.10-0.87; P = .03).
• There were no significant differences in Seattle Angina Questionnaire domains between groups.

“Although CSR implantation was safe, the data showed no significant improvement in CMR perfusion metrics, symptoms, or quality of life compared with a sham procedure in these patients, who currently have no other evidence-based treatment options,” commented Dr. Cheng in the TCT press release.

Ranil de Silva, PhD, who is Chief Investigator of REMEDY-PILOT, added, “We will complement these primary results by reporting data from invasive coronary thermodilution performed as part of a prespecified mechanistic substudy nested within REMEDY-PILOT. Additional randomized, double-blind, placebo-controlled studies will be needed to confirm these results and define whether there is a role for reducer therapies for patients with CMD.”