What is the recommended diagnostic work‑up and acute management for traumatic mitral regurgitation in a patient who has sustained recent blunt chest trauma and now presents with a new murmur, dyspnea, pulmonary edema, or signs of heart failure?

Traumatic Mitral Regurgitation: Diagnostic Work-Up and Acute Management

Immediate Diagnostic Approach

Perform transthoracic echocardiography (TTE) immediately in any patient with blunt chest trauma who presents with a new murmur, dyspnea, pulmonary edema, or signs of heart failure, as this is mandatory for diagnosis and should be done as soon as traumatic mitral regurgitation is suspected. 1

Initial Triage Based on Hemodynamic Status

• Hemodynamically unstable patients (persistent hypotension despite fluid resuscitation) require immediate FAST examination at bedside to exclude pericardial tamponade and tension pneumothorax/hemothorax before proceeding with further imaging 2
• Hemodynamically stable patients should undergo ECG, cardiac troponin measurement, and TTE as the first-line diagnostic triad 1, 2
• Patients with normal ECG and normal cardiac troponin levels have low probability for significant blunt cardiac injury, but the presence of a new murmur or heart failure symptoms mandates echocardiography regardless 2

Echocardiographic Evaluation

TTE is the cornerstone diagnostic modality and must be performed urgently to identify the specific anatomic injury pattern. 1

• Look for a triangular mobile structure representing the head of a flail leaflet prolapsing into the left atrium during systole, which confirms papillary muscle or chordal rupture 1
• Assess for eccentric regurgitant jet directed away from the defective leaflet on color Doppler 1
• Measure vena contracta width (>7 mm indicates severe mitral regurgitation) and calculate effective regurgitant orifice area using PISA method (≥40 mm² indicates severe regurgitation) 1
• Do not rely on color flow jet area alone to quantify severity, as color Doppler underestimates very severe regurgitation and eccentric jets are difficult to assess qualitatively 1

Critical Echocardiographic Distinction

• In acute traumatic mitral regurgitation, the left ventricle and left atrium dimensions are normal or only mildly increased, unlike chronic mitral regurgitation where chambers are significantly enlarged 1
• This finding is crucial because even modest regurgitant volume into a small, non-compliant left atrium causes severe pulmonary congestion and hemodynamic collapse 1

When to Proceed to Transesophageal Echocardiography (TEE)

Perform TEE when TTE is inadequate for determining valve anatomy or when planning surgical strategy. 1

• TEE is particularly indicated when TTE windows are poor or when precise anatomic detail is needed for surgical planning 1, 3
• TEE provides superior visualization of papillary muscle rupture, chordal disruption, and leaflet tears 3

Complementary Imaging

CT Chest with IV Contrast

• Obtain CT chest with IV contrast in hemodynamically stable patients to comprehensively evaluate cardiac chambers, pericardium, coronary arteries, and concomitant thoracic injuries that may be missed on echocardiography 1, 2
• CT can detect cardiac chamber rupture, pericardial rupture, ventricular pseudoaneurysm, and coronary artery dissection 2
• ECG-gated cardiac CT provides additional detail when available 2

Chest Radiography

• Obtain AP chest radiograph as initial screening, though it has limited ability to directly identify valvular injuries 1
• Look for indirect findings suggesting cardiac injury: hemothorax, widened mediastinum, enlarged cardiomediastinal silhouette, abnormal cardiac contour, pneumopericardium, and displaced rib fractures (especially ribs 3-9) 1

Understanding the Injury Patterns

Anatomic Structures Affected (in order of frequency)

1. Papillary muscles (most common, 57% of surgical cases) 4

   • Posterior papillary muscle rupture is far more common than anterior (supplied by single coronary artery) 1
   • Complete rupture presents acutely with devastating hemodynamics requiring emergency surgery 4
   • Partial rupture may have delayed presentation (days to weeks) 3

2. Chordae tendineae (second most common) 4

   • Often presents with delayed onset of symptoms 3

3. Mitral valve leaflets (least common) 4

Clinical Presentation Patterns

• Acute presentation: Complete papillary muscle rupture, especially anterior papillary muscle, causes immediate severe hemodynamic compromise requiring emergency intervention 4, 5
• Delayed presentation: Chordal rupture or partial papillary muscle injury may present days, weeks, or even months after trauma with progressive dyspnea and heart failure 3, 6
• The clinical course can be "indolent or devastating" depending on which structure is injured 4

Acute Management Algorithm

Hemodynamic Support

• Interpret echocardiographic findings in the context of cardiorespiratory support, as positive pressure ventilation and sedation/analgesia significantly reduce the apparent severity of mitral regurgitation 1
• Recognize that manipulation of the circulation and mechanical ventilation alter hemodynamics and echocardiographic findings 1

Surgical Decision-Making

Echocardiography guides the decision and timing for surgery in acute cardiac care. 1

• Emergency surgery is required for complete papillary muscle rupture with acute hemodynamic collapse 4, 5
• Among 82 reported surgical cases, 57% required mitral valve replacement rather than repair 4
• Mitral valve repair is possible in selected cases, particularly with partial papillary muscle tears, using techniques such as papillary muscle reimplantation and ring annuloplasty 6, 7
• Delayed surgical correction is feasible for stable patients with partial injuries, but close monitoring is essential 6

Medical Management Considerations

• Afterload reduction may temporize severe mitral regurgitation in stable patients, but definitive surgical correction is typically required 5
• Serial echocardiographic monitoring is necessary for patients with initially mild regurgitation, as progression can occur 3

Critical Pitfalls to Avoid

• Never assume chest trauma without cardiac symptoms excludes valvular injury: Traumatic mitral regurgitation should be suspected in all patients with significant blunt chest trauma, particularly with sternal or rib fractures 4, 3
• Do not dismiss a new murmur as insignificant: Any new murmur after chest trauma warrants immediate echocardiography 1
• Avoid relying solely on initial presentation: Symptoms may be delayed for days to months, particularly with chordal or partial papillary muscle injuries 3, 6
• Do not use color Doppler jet area alone to assess severity, as this underestimates severe regurgitation 1
• Remember that positive pressure ventilation reduces apparent regurgitation severity: The true severity may be worse than echocardiography suggests in intubated patients 1

Monitoring and Follow-Up

• Obtain serial ECGs and cardiac troponins over 24-48 hours, not just admission values, to detect evolving injury 2
• Monitor for arrhythmias, particularly premature ventricular contractions, which are the most common arrhythmia in blunt cardiac injury 8
• Patients with initially mild regurgitation require close outpatient echocardiographic follow-up, as delayed deterioration can occur 3