Slow enrolment

In the present study, the investigators aim to use the in-vivo Transcatheter Mitral Valve Repair (TMVR) model to determine how Mitral Regurgitation (MR) affects coronary hemodynamics in patients affected with severe MR and concomittant angiographically-documented coronary artery disease. The investigators will also provide unique physiologic data on the acute effect of TMVR using the MitraClip system on coronary microcirculation in patients with severe MR.

Consecutive patients with significant degenerative or functional MR planned for TMVR using the percutaneous edge-to-edge MitraClip system will be assessed for study eligibility. Patients with documented concomitant coronary artery disease, defined as coronary artery stenosis of 50% diameter or more in at least 1 epicardial coronary artery, will be informed about the study. Written informed consent will be obtained from all patients before enrolment in the study.

The TMVR procedure will be performed under general anesthesia with fluoroscopy and transesophageal echocardiographic guidance using the MitraClip device via a femoral venous approach. Cardiac catheterisation and coronary angiography will be undertaken via the transradial route, using standard equipment. The hemodynamic data listed below will be acquired immediately before and after TMVR.

For all lesions, intracoronary blood flow and pressure measurements will be used to generate the following intracoronary physiological parameters:

• Fractional Flow Reserve, FFR.
• Absolute coronary Blood Flow, ABF.
• Coronary Flow Reserve, CFR.
• Index for Microvascular Resistance, IMR.
• Baseline Resistance Index, BRI.
• Resistance Reserve Ratio, RRR.
• Instantaneous wave-free ratio, iFR

Post-procedural evaluation: Patients will be followed up according to local standard clinical practice.

Inclusion Criteria:

1. Age ≥18 years;
2. Patients with significant degenerative or functional MR planned for TMVR with the percutaneous edge-to-edge mitral valve repair MitraClip system;
3. Patients with ≥ 1 coronary artery lesion with angiographically-documented ≥50% diameter stenosis,
4. Patient willing and able to provide written informed consent.

Exclusion Criteria:

1. Previous coronary artery bypass surgery;
2. Presence of ≥1 coronary total occlusion(s);
3. Documented non-viable myocardium in the area of the corresponding coronary artery being studied;
4. Severe left ventricular systolic dysfunction (<30%);
5. Cardiogenic shock/hemodynamic instability at the time of intervention (heart rate<50 beats per minute, systolic blood pressure <90mmHg) and/or need for mechanical/pharmacologic hemodynamic support;
6. Systolic pulmonary artery pressure > 70 mmHg on baseline echocardiography;
7. Significant contraindication to adenosine administration (e.g. heart block, severe asthma);
8. Extremely calcified or tortuous vessels precluding invasive coronary physiology measurement;
9. Acute coronary syndrome with recent ST-elevation myocardial infarction <5 days prior to randomization, or ongoing non-ST elevation acute coronary syndrome with biomarkers (cardiac troponin) still rising;
10. Hypertrophic cardiomyopathy, restrictive pericarditis, constrictive pericarditis, infiltrative cardiomyopathy;
11. Participation or planned participation in another clinical trial, except for observational registries;
12. Patients unable or unwilling to provide written informed consent