What is the emergent management of acute severe (torrential) mitral regurgitation?

Emergent Management of Torrential (Acute Severe) Mitral Regurgitation

Torrential mitral regurgitation is a surgical emergency requiring immediate hemodynamic stabilization with intra-aortic balloon pump and urgent mitral valve surgery—medical therapy alone is temporizing only and definitive surgical intervention must not be delayed. 1, 2

Immediate Diagnostic Confirmation

• Perform transthoracic echocardiography (TTE) immediately to confirm severe MR and identify the mechanism (papillary muscle rupture, chordal rupture, leaflet perforation). 1
• Do not rely on auscultation—the murmur may be soft or completely absent in torrential MR due to rapid equalization of left ventricular and left atrial pressures. 1, 2, 3
• Obtain transesophageal echocardiography (TEE) urgently if TTE is non-diagnostic or when surgical planning requires detailed anatomic assessment, particularly to visualize papillary muscle rupture or valvular vegetations. 1, 2
• Look for a hyperdynamic left ventricle with normal or only slightly enlarged left atrium—chronic compensatory chamber dilation has not yet occurred in acute presentations. 1, 2
• Insert a pulmonary artery catheter to guide hemodynamic management and confirm the diagnosis by detecting large V-waves in the pulmonary capillary wedge pressure tracing. 2, 3

Immediate Hemodynamic Stabilization

Intra-aortic balloon pump (IABP) is the most effective mechanical support and should be inserted immediately to stabilize the patient until definitive surgery can be performed. 1, 2, 3

• IABP reduces left ventricular afterload, decreases regurgitant volume, increases forward cardiac output, and improves coronary perfusion. 1, 2
• Consider percutaneous mechanical circulatory support devices (e.g., Impella) in patients with refractory cardiogenic shock as a bridge to surgery. 1, 4

Pharmacologic Support (Temporizing Only)

• Administer intravenous vasodilators (sodium nitroprusside or nicardipine) if systolic blood pressure >100 mmHg to reduce afterload and preferentially direct flow away from the regurgitant pathway. 1, 2, 3
• Use inotropic agents (dobutamine 2-20 mcg/kg/min) if systolic blood pressure is 70-100 mmHg to maintain cardiac output. 2
• Administer IV diuretics (furosemide 0.5-1.0 mg/kg) for pulmonary congestion, but avoid excessive preload reduction. 2
• Vasodilator therapy is frequently limited by systemic hypotension—do not delay surgery attempting to optimize medical therapy. 1, 2

Definitive Surgical Management

Prompt mitral valve surgery is mandatory for acute severe primary MR—this is a Class I recommendation. 1, 5

• Obtain immediate surgical consultation when torrential MR is confirmed—do not delay for "medical optimization." 2, 3
• Complete papillary muscle rupture causes torrential MR that is uniformly fatal without surgery—even partial rupture requires urgent intervention as it can suddenly progress to complete rupture. 1, 2
• Mitral valve replacement, not repair, is required for papillary muscle rupture due to extensive tissue necrosis and structural damage that precludes reliable repair. 2, 3
• Mitral valve repair is usually feasible for ruptured chordae tendineae and should be attempted when anatomically possible. 1
• Perform concomitant coronary artery bypass grafting (CABG) at the time of valve surgery if the acute MR is due to myocardial infarction to address the culprit coronary lesion. 2

Surgical Timing

• Operate emergently without delay—even hemodynamically stable patients with confirmed papillary muscle rupture can collapse suddenly. 2
• Surgical mortality for papillary muscle rupture ranges 20-87%, but medical therapy alone carries near-certain death. 2
• Most mechanical complications occur within 24 hours to 7 days post-MI, with sudden hemodynamic deterioration as the presenting feature. 2

Critical Pitfalls to Avoid

• Do not dismiss the diagnosis based on absence of a murmur—severe acute MR is frequently silent due to rapid pressure equalization. 1, 2, 3
• Do not delay surgery for medical stabilization in confirmed rupture—temporizing measures are only to bridge to immediate operation. 2
• Do not attempt mitral valve repair in acute papillary muscle rupture—replacement is required. 2, 3
• Do not forget coronary revascularization—CABG must accompany valve surgery in ischemic etiologies. 2

Special Considerations by Etiology

Post-Myocardial Infarction

• The posteromedial papillary muscle is most vulnerable due to singular blood supply from the right coronary or circumflex artery. 2
• Inferior wall MI directly threatens this blood supply, making papillary muscle rupture more likely. 2
• Suspect rupture when sudden deterioration occurs 2-7 days post-MI with pulmonary edema and/or cardiogenic shock. 2, 3

Infective Endocarditis

• TEE is essential to detect valvular vegetations, leaflet perforation, annular abscesses, or chordal/papillary muscle rupture. 1, 6
• Native or prosthetic valve damage can occur, requiring individualized surgical approach. 6

Transcatheter Options (Highly Selected Cases Only)

• Transcatheter mitral valve repair (TMVr) may be considered in patients who are absolutely prohibitive surgical candidates, but this is not standard of care for acute torrential MR. 7, 4
• TMVr combined with mechanical circulatory support has been reported in case series for refractory cardiogenic shock, but surgical intervention remains first-line. 7, 4