An interventional study of Coronary sinus reducer and Placebo procedure in Hypertrophic Cardiomyopathy, sponsored by Imperial College London. Not yet recruiting at 8 sites in United Kingdom. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-08.
Sponsored by Imperial College London · Not applicable, Interventional, and Treatment
Hypertrophic cardiomyopathy (HCM) is a common heart condition in which the heart muscle becomes abnormally thick. In non-obstructive HCM, blood flow out of the heart is not blocked, but many patients still experience chest pain, breathlessness and limitation of daily activities. This may be because the small blood vessels within the thickened heart muscle do not supply enough blood and oxygen, particularly during exercise or stress.
Current treatment options for symptomatic non-obstructive HCM are limited.
This study will test a small device called the coronary sinus reducer (CSR), which is placed into a vein of the heart using a catheter. The CSR is designed to improve blood flow to areas of heart muscle that are short of blood supply.
Fifty adults with non-obstructive HCM, ongoing symptoms and reduced blood supply on a heart MRI scan will take part.
Participants will be randomly assigned to receive either CSR implantation or a placebo procedure. Neither participants nor the follow-up research team will know which procedure was performed until the 6-month follow-up assessments are complete.
The investigators will use detailed heart MRI scans to measure blood flow, a smartphone app to record daily symptoms, coronary sinus blood tests to look for biochemical evidence of reduced oxygen supply, and invasive coronary physiology measurements to assess the small blood vessels of the heart. The main aim is to find out whether the CSR improves blood flow and reduces symptoms. The results may identify a new treatment option for patients with non-obstructive HCM and improve understanding of the disease.
Type of study: Double-blind, randomised, placebo-controlled trial of 50 adult patients with symptomatic non-obstructive HCM and perfusion defects on stress perfusion CMR.
Patients will be assessed at 3 time points: enrolment, randomisation and follow-up.
Enrolment assessment will consist of symptom questionnaires, onboarding onto the ORBITA-app (a smartphone application for daily symptom reporting), and reviewing the stress perfusion CMR (needed on clinical grounds for enrolment to the study). Patients will then enter a 2-week period prior to randomisation during which participants input their symptoms into the ORBITA-app. Patients without any symptoms during this period will be withdrawn from the study.
Eligible participants will proceed to a blinded catheter laboratory procedure involving internal jugular venous access for right atrial pressure measurement and coronary sinus sampling, and randomisation 1:1 to CSR implantation or placebo. Blinding will be maintained for participants with headphones for auditory isolation and a deep level of conscious sedation.
A subsection of suitable and consenting participants will also undergo invasive coronary physiology assessment, including coronary angiography, pressure-wire assessment and thermodilution measurements. Participants who are not suitable or who do not consent to invasive coronary physiology will continue in the main study. The invasive physiology assessment will be completed before randomisation so that baseline measurements are not influenced by treatment allocation.
Participants will enter a 6-month blinded follow-up period with daily symptom reporting via the ORBITA-app. After 6 months, participants will return for repeat symptom questionnaires and stress perfusion CMR. Participants included in the invasive physiology substudy will be invited to undergo a planned repeat research coronary angiography and invasive physiology assessment at 6 months.
347 studies on the registry are indexed under Cardiomyopathy, Hypertrophic; 110 are open to participants now.
This study's planned enrollment of 50 is below the median of 59 across 171 interventional studies indexed under Cardiomyopathy, Hypertrophic.
Browse Cardiomyopathy, Hypertrophic studies →Imperial College London is the lead sponsor of 825 studies on the registry; 179 are open to participants now.
Of its 9 completed or terminated interventional studies of FDA-regulated products, 6 (67%) have results posted.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Participants allocated to CSR will have the device implanted into the coronary sinus.
Device: Coronary sinus reducer
Participants in the placebo group will not have the device implanted, but will remain sedated in the catheter laboratory for 15-30 minutes so that the experience is similar and blinding is maintained.
Procedure: Placebo procedure
The Shockwave Reducer (coronary sinus reducer) is intended to create a controlled narrowing that increases coronary sinus pressure and redistributes venous blood flow from epicardial to subendocardial regions, thereby improving myocardial perfusion in areas of microvascular ischaemia.
Also known as: Shockwave Reducer, RED-001
Participants in the placebo group will not have the device implanted, but will remain sedated in the catheter laboratory for 15-30 minutes so that the experience is similar and blinding is maintained.
Daily symptom frequency during blinded 6-month follow-up
Patient-reported. ORBITA-app daily symptom reporting.
Time frame: During blinded 6-month follow-up
The change in ratio of stress MBF in ischaemic versus non-ischaemic myocardial subsegments at 6 months comparing CSR and placebo groups
Quantitative stress perfusion CMR.
Time frame: Baseline and 6 months
Coronary sinus lactate concentration during adenosine stress
Coronary sinus blood samples obtained during adenosine stress and analysed immediately using a standard blood gas analyser to determine lactate concentration.
Time frame: Randomisation procedure
Coronary sinus pH during adenosine stress
Coronary sinus blood samples obtained during adenosine stress and analysed immediately using a standard blood gas analyser to determine pH.
Time frame: Randomisation procedure
MacNew Heart Disease Health-related Quality of Life Questionnaire
Global score range 1 to 7; higher scores indicate better health-related quality of life.
Time frame: Baseline and 6-month follow-up
Kansas City Cardiomyopathy Questionnaire Clinical Summary Score (KCCQ-CSS)
The Kansas City Cardiomyopathy Questionnaire (KCCQ-23) Clinical Summary Score will be derived. Score range 0 to 100; higher scores indicate better health status.
Time frame: Baseline and 6-month follow-up
EQ-5D-5L
EuroQol 5-Dimension 5-Level questionnaire. Each dimension is scored from 1 (no problems) to 5 (extreme problems); lower levels indicate better health status.
Time frame: Baseline and 6-month follow-up
Index of microcirculatory resistance (IMR)
Coronary angiography with pressure-wire and thermodilution.
Time frame: Baseline and 6-month follow-up in suitable and consenting participants included in the invasive physiology substudy
Coronary flow reserve (CFR)
Coronary angiography with pressure-wire and thermodilution.
Time frame: Baseline and 6-month follow-up in suitable and consenting participants included in the invasive physiology substudy
Fractional flow reserve (FFR)
Coronary angiography with pressure-wire and thermodilution.
Time frame: Baseline and 6-month follow-up in suitable and consenting participants included in the invasive physiology substudy
Absolute flow
Coronary angiography with pressure-wire and thermodilution.
Time frame: Baseline and 6-month follow-up in suitable and consenting participants included in the invasive physiology substudy
Absolute resistance
Coronary angiography with pressure-wire and thermodilution.
Time frame: Baseline and 6-month follow-up in suitable and consenting participants included in the invasive physiology substudy
Microvascular resistance reserve (MRR)
Coronary angiography with pressure-wire and thermodilution.
Time frame: Baseline and 6-month follow-up in suitable and consenting participants included in the invasive physiology substudy
Stress myocardial blood flow (MBF) in ischaemic, non-ischaemic myocardial segments, and globally
Quantitative stress perfusion CMR. Myocardial blood flow will be quantified in mL/g/min.
Time frame: Baseline and 6-month follow-up
Rest myocardial blood flow (MBF) in ischaemic, non-ischaemic myocardial segments, and globally
Quantitative stress perfusion CMR. Myocardial blood flow will be quantified in mL/g/min at rest.
Time frame: Baseline and 6-month follow-up
Myocardial perfusion reserve (MPR) in ischaemic, non-ischaemic myocardial segments, and globally
Quantitative stress perfusion CMR. Myocardial perfusion reserve will be calculated as the ratio of stress myocardial blood flow to rest myocardial blood flow.
Time frame: Baseline and 6-month follow-up
Endocardial:epicardial perfusion ratio
Quantitative stress perfusion CMR.
Time frame: Baseline and 6-month follow-up
Myocardial scar
Late gadolinium enhancement burden will be recorded.
Time frame: Baseline and 6-month follow-up
Myocardial strain
Quantitative stress perfusion CMR.
Time frame: Baseline and 6-month follow-up
Plan to share: No
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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