Coronary Sinus Reducer Objective Impact on Symptoms, MRI Ischaemia and Microvascular Resistance

Coronary Sinus Reducer Objective Impact on Symptoms, MRI Ischaemia and Microvascular Resistance

ORBITA-COSMIC is a randomised, double-blinded, placebo controlled trial of the coronary sinus reducer (CSR). The investigators will compare the effects of CSR versus placebo on myocardial perfusion on MRI, exercise time and symptoms in 50 participants with refractory angina and ischaemia.

Inclusion Criteria:

• Stable coronary artery disease (CAD) not eligible for percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG)
• Evidence of ischaemia on stress perfusion CMR
• Angina - Canadian Cardiovascular Society Class II-VI on maximal medical therapy

Exclusion Criteria:

• Age<18 years
• Pregnancy
• Inability to consent
• Recent acute coronary syndrome (3 months)
• Recent revascularisation (6 months)
• Permanent pacemaker or defibrillator leads in the right heart
• Severe left ventricular impairment (<25%)
• Indication for cardiac resynchronisation therapy (CRT)
• Right atrial pressure ≥15mmHg
• Life expectancy <1 year
• Severe renal impairment (eGFR<15)
• Contraindication to CMR
• Contraindication to adenosine
• Ischaemia isolated to inferior wall
• Ongoing participation in a separate interventional study