Coronary Sinus Reducer for treating refractory microvascular angina

A Multicentric Randomized Open Label Controlled Superiority Trial to Evaluate the Effectiveness of a Therapy With a Coronary Sinus Reducer as Compared to Guideline-directed Medical Therapy in Patients With Refractory Microvascular Angina

Not applicable Interventional Johannes Gutenberg University Mainz · NCT04606459

This study is testing whether a device called the Coronary Sinus Reducer can help people with severe chest pain from microvascular angina feel better when combined with their usual heart medications.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment144 (estimated)
Ages18 Years to 85 Years
SexAll
SponsorJohannes Gutenberg University Mainz Academic / other
Locations1 site (Mainz, Rhineland-Palatinate)
Trial IDNCT04606459 on ClinicalTrials.gov

What this trial studies

This clinical trial investigates the effectiveness of a Coronary Sinus Reducer in patients with refractory microvascular angina. Participants will be randomly assigned to receive either the device along with optimal medical therapy or optimal medical therapy alone. The primary goal is to determine if there is a significant improvement in angina symptoms, measured by changes in the Canadian Cardiovascular Society (CCS) angina class, after six months. The study aims to address the high prevalence and burden of microvascular disease, which affects a substantial number of patients with angina but no obstructive coronary artery disease.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 to 85 with chronic coronary syndrome and refractory angina despite optimal medical therapy.

Not a fit: Patients who have experienced recent acute coronary syndrome or revascularization procedures may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly improve the quality of life for patients suffering from refractory microvascular angina.

How similar studies have performed: While the approach is innovative, similar studies have not been widely conducted, making this a novel investigation in the field.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Age ≥ 18 and ≤85 years
* Chronic coronary syndrome (including patients with anginal equivalents) refractory angina CCS class III-IV despite guideline-directed medical therapy
* Evidence of reversible ischemia on non-invasive testing
* Evidence of microvascular disease as diagnosed invasively by at least one of the following:

  1. index of microvascular resistances (IMR) \>25 and/or
  2. coronary flow reserve (CFR) \<2.0) with fractional flow reserve (FFR)\>0.8.
* Willingness to participate and ability to understand, read and sign the informed consent document before enrollment in the trial.

Exclusion Criteria:

Subjects presenting at least one of the following criteria will not be enrolled in the trial

* Recent (within 3 months) acute coronary syndrome
* Recent (within 6 months) revascularization by percutaneous coronary intervention (PCI, stent) or coronary artery by-pass surgery (CABG)
* Recent (within 30 days) unsuccessful PCI
* Decompensated congestive heart failure (CHF) or hospitalization due to CHF during the last 3 months
* Left ventricular ejection fraction of \<30%
* Mean right atrial pressure \>15mmHg
* Anomalous or abnormal CS anatomy (e.g., tortuosity, aberrant branch, persistent left superior vena cava \[SVC\]) as demonstrated by angiogram
* CS diameter at the site of planned Reducer implantation greater than 13mm or less than 9.5mm as measured by angiogram
* Severe chronic obstructive pulmonary disease (COPD) indicated by a forced expiratory volume in one second that is less than 55 percent of the predicted value
* Severe valvular heart disease
* A pacemaker electrode in the coronary sinus
* Tricuspid valve replacement or repair
* Chronic renal failure (serum creatinine \>2mg/dL), and/or on chronic hemodialysis
* Moribund, or with comorbidities limiting life expectancy to less than one year
* Known severe reaction to required procedural medications
* Known allergy to stainless steel or nickel
* Need for Magnetic Resonance Imaging (MRI) within 8 weeks after reducer implantation
* Contraindication to dual antiplatelet therapy
* Female of childbearing potential (last menstruation within the last 12 months or who did not undergo tubal ligation, ovariectomy or hysterectomy)

Where this trial is running

Mainz, Rhineland-Palatinate

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Coronary Microvascular DiseaseRefractory Angina
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.