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Testing a Coronary Sinus Reducer for Microvascular Heart Disease and Angina

Tests a small mesh device against a sham procedure in adults with heart-related chest pain.

Key facts

Who runs it
UMC Utrecht
Where
Rotterdam and Utrecht, NetherlandsSee the 2 sites
Trial code
Registry title
Coronary Sinus Reducer in Coronary Microvascular Disease
Status
Enrolling by invitation
People taking part
50 people, planned
Started
20 Nov 2025
Expected to end
1 Nov 2028
Type of study
Interventional, 2 groupsOne group gets a sham (pretend) treatment, for comparison.
Treatments tested
  • Coronary sinus reducer
  • Sham CSR procedure
Record updated
4 December 2025

Who can take part

AI summary

From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.

The trial is looking for adults with angina and a poorly working small heart blood vessels (coronary microvascular dysfunction) who still have symptoms despite medicines. Some will get a coronary sinus reducer device and some a sham procedure.

Age
40 years and older
Sex
All sexes can join.
Disease stage
Coronary microvascular dysfunction in the LAD artery, with a coronary flow reserve (CFR) below 2.5. Angina of Canadian Cardiovascular Society Class II-IV.
Earlier treatment
On at least two anti-anginal medicines, or on the most medicine the person can tolerate if fewer than two.
Biomarker or test result
Abnormal absolute coronary flow reserve (CFR<2.5), confirmed during the study procedure by thermodilution with saline-induced hyperaemia.

Main reasons for not taking part

  • Significant narrowing of the main heart arteries
  • Recent acute coronary syndrome (within 3 months) or recent stent procedure (PCI, within 6 months)
  • Pregnancy or planned pregnancy within the next 12 months
  • Severe left ventricular impairment (ejection fraction <35%) or NYHA class IV or decompensated heart failure
  • Life expectancy <1 year

The registry criteria, word for word

Show all 25 criteriaShow less

Who can take part

  • Coronary microvascular dysfunction in the left anterior descending coronary artery (LAD) as expressed by abnormal absolute coronary flow reserve (CFR<2.5) confirmed during the index study procedure using the continuous thermodilution technique and saline-induced coronary hyperaemia
  • Angina - Canadian Cardiovascular Society Class II-IV on at least two anti-anginals or maximally tolerated medical therapy if less than two
  • Patient understands the nature of the procedure and provides written informed consent for the study prior to enrolment

Who cannot take part

  • Prior positive acetylcholine provocation test with respect to epicardial vasospasm following the COVADIS criteria
  • NYHA class IV or decompensated heart failure or hospitalization due to heart failure within 90 days before the index procedure
  • Recent implantation of a permanent pacemaker or defibrillator lead in the right ventricle or atrium (within 90 days before the index procedure)
  • Contra-indication to short term dual antiplatelet therapy or lifelong aspirin treatment
  • Currently enrolled in another investigational device or drug trial that has not completed the primary endpoint or that clinically interferes with the current study endpoints
  • Severe pulmonary hypertension
  • Recent acute coronary syndrome (within 3 months)
  • Severe arrhythmias, including chronic atrial fibrillation with persistent rapid ventricular response (>100bpm despite medication)
  • Indication for cardiac resynchronization therapy
  • Severe valvular heart disease
  • History of tricuspid valve replacement or repair
  • Severe left ventricular impairment (left ventricular ejection fraction <35%)
  • Age < 18 years
  • Absence of symptoms reported on the ORBITA-app during the 2-week screening period
  • Presence of hemodynamically significant epicardial stenoses based on both non- hyperaemic pressure ratio (NHPR; iFR≤0.89, or RFR≤0.89, or dFR/dPR≤0.89) or fractional flow reserve (FFR≤0.80) assessments
  • Mean right atrial pressure ≥15 mmHg
  • Coronary sinus anatomy not suitable for CSR implantation
  • Pregnancy or planned pregnancy within the next 12 months
  • Recent revascularization with PCI (within 6 months)
  • Presence of a pacemaker lead in the coronary sinus
  • Known inability to tolerate contrast medium
  • Life expectancy <1 year

Where in Netherlands

  • Maasstad ZiekenhuisRotterdam, NetherlandsNo longer taking part
  • UMC UtrechtUtrecht, NetherlandsNo longer taking part

About the trial

What the trial wants to find out

Coronary microvascular dysfunction (CMD) is a common cause of treatment- resistant angina that lacks evidence-based treatment options. The coronary sinus reducer (CSR) is an hourglass-shaped stainless steel mesh, designed to create a controlled narrowing of the coronary sinus (CS). By augmenting CS pressure, CSR implantation was shown to improve myocardial perfusion, potentially providing a novel treatment for patients with CMD. REDUCE CMD is a placebo-controlled study of CSR in 50 patients with CMD. The main study endpoints are the change in coronary flow reserve from baseline to 6 months in the CSR-arm versus the placebo arm, and the difference in number of daily episodes of angina recorded on the ORBITA-app at 6 month follow-up in the CSR-arm versus the placebo arm.

The 2 groups in the trial

  • ShamSham treatment, for comparison

    Patients in this arm undergo a sham CSR procedure.

    Treatment: Sham CSR procedure

  • CSR armTreatment being tested

    Patients in this arm undergo coronary sinus reducer implantation.

    Treatment: Coronary sinus reducer

Questions to ask the study team

  1. How often do I need to come in, and for how long each time?
  2. Are travel costs paid?
  3. Can I keep my own doctor?
  4. What happens if I want to stop?

Contact the study team: see the registry record → Contacts and Locations

Print a page for my doctor

Data and sources

Registry record
Listed on ClinicalTrials.gov.
Official title
Impact of the Coronary Sinus Reducer on Coronary Flow Reserve and Symptoms in Patients With Coronary Microvascular Disease
Plain-language title
Testing a Coronary Sinus Reducer for Microvascular Heart Disease and AnginaGenerated from the registry record. The registry title is the official one.
AI summary
From the trial's eligibility criteria. Read by machine on 12 November 2026.
Record updated
4 December 2025