- Surgical risk: Subject is eligible for cardiac surgery (specific risk score or comorbidities should demonstrate high risk features, as determined by the Heart Team) High risk for mitral valve surgery is defined utilizing established risk scores (STS, Euro-Score II) in conjunction with comorbidities as recommended by MVARC (frailty index; major organ system compromise not to be improved postoperatively; procedure specific impediments) (MVARC Part 1)