Rescue transventricular off-pump mitral valve repair with artificial neochords for acute mitral regurgitation due to postinfarction papillary muscle rupture

Management of Severe Mitral Regurgitation in Patients With Acute Myocardial Infarction: JACC Focus Seminar 2/5

Severe acute mitral regurgitation after myocardial infarction includes partial and complete papillary muscle rupture or functional mitral regurgitation. Although its incidence is <1%, mitral regurgitation after acute myocardial infarction frequently causes hemodynamic instability, pulmonary edema, and cardiogenic shock. Medical management has the worst prognosis, and mortality has not changed in decades. Surgery represents the gold standard, but it is associated with high rates of morbidity and mortality. Recently, transcatheter interventions have opened a new door for management that may improve survival. Mechanical circulatory support restores vital organ perfusion and offers the opportunity for a steadier surgical repair. This review focuses on the diagnosis and the interventional management, both surgical and transcatheter, with a glance on future perspectives to enhance patient management and eventually decrease mortality.

Mitral valve repair in papillary muscle rupture

Papillary muscle rupture (PMR) is a significant mechanical complication following myocardial infarction (MI), a condition associated with a high mortality. It results in severe mitral valve regurgitation (MR), often accompanied by cardiogenic shock and pulmonary edema, requiring both emergent medical treatment and surgical intervention. Surgical treatment includes either chordal sparing mitral valve replacement or mitral valve repair, which is associated with a high mortality. Mitral valve repair is believed to be superior to mitral valve replacement with respect to improving left ventricular function, albeit with risk of repair failure and resulting in increased cross clamp times. Concomitant coronary revascularization may improve both short- and long-term outcomes after surgery. With advances in medical innovations in the field of transcatheter devices, these devices may serve as a bridge to recovery or treatment in the setting of acute MR due to PMR. However, long-term data will be required to establish the non-inferiority of one treatment modality over the other. Management of these patients should be guided by a dedicated mitral heart team.

Inferior Wall ST-Elevation Myocardial Infarction Complicated by Left Ventricular Pseudoaneurysm, Cardiac Tamponade, and Partial Papillary Muscle Rupture

Papillary muscle rupture (PMR) is a rare complication of myocardial infarction. Its incidence has been decreasing nowadays because of improved early revascularization techniques. When it occurs, surgical treatment is the only therapeutic lifesaving approach. We report a case of an 85-year-old female patient who presented to the emergency room with chest pain. An electrocardiogram showed inferior wall ST-elevation myocardial infarction. The patient was revascularized emergently with a drug-eluting stent to the obtuse marginal artery. An intra-aortic balloon pump was inserted for hemodynamic support. Six hours later, the patient developed shortness of breath with persistent hypotension. A transthoracic echocardiogram (TTE) showed a large pericardial effusion with a pseudoaneurysm in the infero-septal apex. Immediate drainage of pericardial fluid was performed. Seventy-two hours later, the patient had flash pulmonary edema. A new severe eccentric mitral regurgitation was discovered on transesophageal echocardiography (TEE). Findings revealed a partial posteromedial papillary muscle tear and prolapse of the A2 scallop. The patient was not a candidate for surgical replacement or percutaneous repair due to the high surgical risk and poor functional status, and she passed away on day fifteen of her hospital stay. Limited case series have shown promising benefits of percutaneous edge-to-edge mitral valve repair in selected high surgical risk patients and as a bridge to definitive mitral valve replacement. A diagnosis of PMR should be in the differential diagnosis, especially when evaluating hemodynamically unstable patients who present with prolonged symptoms.