Hypertrophic CardiomyopathyCOSMIC-HCMNCT07865364
Coronary Sinus Reducer Objective Impact on SymptoMs, Ischaemia and miCrovascular Resistance in Non-obstructive Hypertrophic CardioMyopathy
A study testing Coronary sinus reducer in people with Hypertrophic Cardiomyopathy, run by Imperial College London at 8 sites in United Kingdom.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Hypertrophic Cardiomyopathy
- What is being tested?
- Coronary sinus reducer
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 50 participants
- Where
- 8 sitesUnited Kingdom
- Study dates
- 1 Oct 2026to Sep 2029
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Non-obstructive hypertrophic cardiomyopathy (LVOT gradient ≤30 mmHg at rest on echocardiography)
- Ongoing symptoms despite current medical therapy
- Significant perfusion defects (≥ 2 myocardial segments) on stress perfusion CMR
Who cannot join
- Age < 18 years
- Left ventricular impairment LVEF <55%
- Severe renal impairment (Estimated glomerular filtration rate <30mL/min/1.73m2)
- Right atrial pressure ≥ 15 mmHg
- Contraindication to CMR, gadolinium contrast, or adenosine.
- Implantable cardioverter defibrillator or other device likely to compromise CMR interpretation.
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- Disease modifying drug treatment (mavacamten/aficamten) in past 6 months
- Contraindication or intolerance to the required antiplatelet therapy
- Obstructive epicardial coronary artery disease, defined as significant angiographic stenosis or physiologically significant disease at investigator discretion
- Pregnancy
- Inability to consent
Trial locations and contacts
8 sites in 1 country. Contact the study team or a site near you to ask about taking part.
8 sites in 1 country
United Kingdom8 sites
University Hospitals Bristol and Weston Nhs Foundation Trust
Bristol, BS1 3NU
Research Governance and Integrity Team, 02075949832, rgit@imperial.ac.uk
Liverpool Heart and Chest Hospital Nhs Foundation Trust
Liverpool, L14 3PE
Research Governance and Integrity Team, 02075949832, rgit@imperial.ac.uk
Barts Health Nhs Trust
London, E1 2ES
Research Governance and Integrity Team, 02075949832, rgit@imperial.ac.uk
Guy'S and St Thomas' Nhs Foundation Trust
London, SE1 7EH
Research Governance and Integrity Team, 02075949832, rgit@imperial.ac.uk
Imperial College Healthcare NHS Trust
London, W2 1BL
Research Governance and Integrity Team, 02075949832, rgit@imperial.ac.uk
Oxford University Hospitals Nhs Foundation Trust
Oxford, OX3 9DU
Research Governance and Integrity Team, 02075949832, rgit@imperial.ac.uk
University Hospitals Dorset Nhs Foundation Trust
Poole, BH15 2JB
Research Governance and Integrity Team, 02075949832, rgit@imperial.ac.uk
Mid and South Essex Nhs Foundation Trust
Westcliff-on-Sea, SS0 0RY
Research Governance and Integrity Team, 02075949832, rgit@imperial.ac.uk
About this study
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.
Read more
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.
Read the detailed description
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.
- Conditions
- Hypertrophic Cardiomyopathy
- Being tested
- Coronary sinus reducer, Placebo procedure
- Keywords
- Coronary sinus reducer, angina, myocardial ischaemia, non-obstructive hypertrophic cardiomyopathy, microvascular dysfunction
- Medical subject headings
- Cardiomyopathy, Hypertrophic, Angina Pectoris, Coronary Artery Disease
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Coronary sinus reducerDevice
Also called Shockwave Reducer, RED-001
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.
Placebo procedureProcedure or surgery
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.
| Study group | Role | What they receive |
|---|---|---|
| CSR implantation | Experimental | Participants allocated to CSR will have the device implanted into the coronary sinus. Receives: Device: Coronary sinus reducer |
| Placebo procedure | Placebo comparator | 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. Receives: Procedure: Placebo procedure |
What is being measured
The primary outcome is the main question the study is designed to answer.
Daily symptom frequency during blinded 6-month follow-up
Patient-reported. ORBITA-app daily symptom reporting.
Measured: 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.
Measured: Baseline and 6 months
Secondary outcomes (11)
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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: Baseline and 6-month follow-up
Index of microcirculatory resistance (IMR)
Coronary angiography with pressure-wire and thermodilution.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: Baseline and 6-month follow-up in suitable and consenting participants included in the invasive physiology substudy
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Oct 2026
- Study start1 Oct 2026 (estimated)
- Primary completionSep 2029 (estimated)
- Study completionSep 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Hypertrophic CardiomyopathyStudies of the same condition, open and under way.
- More trials run by Imperial College LondonThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants will be randomised 1:1 to CSR or placebo; no device will be deployed in the placebo arm.
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 50 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Imperial College London
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07865364
- Sponsor's protocol ID
- 355828
- Other IDs
- FS/CRTF/26/24874
- Acronym
- COSMIC-HCM
- Status last verified
- Sep 2026
- First submitted
- 28 Sep 2026
- Last updated
- 8 Oct 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No