Severe Mitral Regurgitation due to Traumatic Anterolateral Papillary Muscle Rupture: A Case Report
A 29-year-old man was admitted for dyspnea and hemoptysis via the emergency department. His medical history was unremarkable. Ten hours before admission, he was involved in an automobile accident in which his car crashed into a tree along the street. At that time, he was not wearing his seat belt and was driving under the influence of alcohol. He was initially treated at a local medical center where, after a battery of diagnostic and imaging work-ups, which included brain and chest computed tomography (CT), he was assessed to be fine except for a nasal bone fracture. However, after several hours, he experienced abrupt dyspnea and hemoptysis (about 40 mL) for which he promptly visited the emergency department of our hospital. On arrival, he was mentally alert with a blood pressure of 130/80 mmHg, a pulse rate of 140 beats per minute (bpm), a respiratory rate of 25 bpm, body temperature of 36.5℃, and SpO2 of 70% after 10 L of O2 by mask. On lung auscultation, we heard rales. The echocardiogram findings were compatible with acute myocardial infarction and sinus tachycardia. Laboratory findings showed creatine kinase-MB (CK-MB) of 75.2 ng/mL and troponin I of 15.04 ng/mL. An initial chest X-ray showed mild consolidation and ground-glass opacity in both lung fields (). On arterial blood gas analysis, the pulmonary arterial oxygen saturation was 43.1 mmHg. Traumatic lung contusion was suspected, and due to the severe dyspnea the patient was placed on mechanical ventilation. A serial chest X-ray a few hours later showed aggravated bilateral lung consolidation. Despite inotropic support, hemodynamic instability persisted, for which transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) were performed on hospital day 4 (). The findings revealed an acute mitral regurgitation due to papillary muscle rupture necessitating emergency cardiac surgery.\nWe performed an emergency operation. The right ventricle and atrium appeared distended. Hematoma and tearing were found around the anterolateral left ventricular (LV) wall, and the myocardium of this area was akinetic. A standard cardiopulmonary bypass with bicaval cannulation was initiated, and cold hematic cardioplegia was performed for myocardial protection after aortic cross-clamping. As active bleeding from the anterolateral LV wall tear was no longer noted, the lesion was reinforced with the application of Tachocomb (4×6 cm; CSL Behring, Tokyo, Japan), BioGlue (CryoLife, Kennesaw, GA, USA), and Surgicel (Johnson & Johnson, New Brunswick, NJ, USA). The left atrial cavity was approached through a transseptal atrial incision, which revealed a completely detached anterolateral papillary muscle head and rupture of the accessory chordae tendineae (). The detached papillary muscle was necrotic and edematous. As mitral valve replacement was judged to be the best therapeutic option, mitral valve replacement was performed with a 27 mm (SJM 27MECJ-502 mitral valve; St. Jude Medical Inc., St. Paul, MN, USA) mechanical valve.\nAs the patient showed rapid symptomatic improvement, he was extubated on post-operative day 2. A pericardiostomy was performed on post-operative day 20 for significant pericardial effusion. Afterwards, the patient improved gradually.