The ACC Task Force on Expert Consensus Decision Pathways published its 2017 Expert Consensus Decision Pathway on the Management of Mitral Regurgitation (MR) on October 18 in the Journal of the American College of Cardiology.

The decision pathway focuses on the evaluation and management of patients with MR, with an emphasis on 1) clinical assessment; 2) proper identification of the mechanism and etiology of MR; 3) determination of MR severity; 4) assessment of the feasibility of surgical or transcatheter repair in appropriate patients; and 5) indications for referral to a regional comprehensive valve center. The recommendations are based on the 2014 American Heart Association (AHA)/ACC Guideline for the Management of Patients with Valvular Heart Disease and its 2017 focused update.

Evaluation of the Patient

• In asymptomatic patients, exercise testing with echocardiography may elicit symptoms and reveal elevated pulmonary artery systolic pressures, worsening MR, or failure of left or right ventricular systolic function to augment normally. Transthoracic echocardiography (TTE) is most often used to identify the MR mechanism and etiology.
• Comprehensive assessment of multiple parameters is recommended to determine MR severity, including pathoanatomy of the mitral apparatus, left ventricular (LV) size and function, left atrial (LA) size and volume, pulmonary artery pressure and the presence of atrial fibrillation. Severity is usually assessed with color flow Doppler during TTE or transesophageal echocardiography. Quantitative parameters should be calculated, including effective regurgitant orifice area, regurgitant volume and regurgitant fraction.
• Prognostic variables include age, heart failure, coronary artery disease and functional class. LV ejection fraction (EF) <60 percent, LV end-systolic diameter >40 mm, and LA systolic volume index >60 mL/m2 are associated with a worse prognosis. Secondary MR appears to be an independent marker of adverse prognosis.

Management of MR

• Optimal treatment decisions are based on MR type and severity, hemodynamic consequences, disease stage, patient comorbidities and the experience of the heart valve team and its members. An algorithm is provided to aid in evidence-based management.
• Surgery is the principal treatment for primary MR. Medical and device therapies are used for secondary MR before surgery is attempted. Mitral valve surgery is indicated for symptomatic (Stage D) or asymptomatic (Stage C2) patients with primary severe MR and EF >30 percent. The main goals of mitral valve repair are to restore leaflet coaptation depth to >5 mm, stabilize and remodel the annulus, restore normal leaflet motion and eliminate MR. Surgeon experience is an important determinant of successful repair.
• Edge-to-edge mitral leaflet coaptation using a clip is the only transcatheter treatment approved in the U.S. Its use is restricted to symptomatic patients with severe primary MR, reasonable life expectancy and prohibitive surgical risk.
• Long-term follow-up after intervention for assessment of durability, functional outcomes and survival is recommended.

The decision pathway provides clinicians with tools to improve the care of patients with MR. According to the authors, multidisciplinary heart teams composed of experienced surgeons, interventionists, expert imagers and others are vital to providing advanced care for challenging patients at comprehensive valve centers. They concluded, “Closing the existing knowledge and treatment gaps in the management of these patients requires ongoing collaboration across primary care, cardiology, and cardiac specialties, as emerging technologies for the treatment of MR are evaluated with a dedicated focus on high-quality outcomes.”