Prosthetic Mitral Valve Leaflet Escape
A 72-year-old woman visited emergency department as she suddenly experienced chest pain with resting dyspnea [New York Heart Association (NYHA) functional class IV] while washing dishes at home. She underwent mitral valve replacement 27 years ago, at the age of 45, due to mitral stenosis. Mitral valve replacement was done with Edwards-Duromedics 29 mm mitral valve (Baxter Healthcare Corp., Cleveland, MS, USA). Apart from valvular heart disease, the patient was on medication for diabetes mellitus and hypertension as well as paroxysmal atrial fibrillation. She remained to be the status of NYHA functional class II and anticoagulation with coumadin was appropriately done (international normalized ratio 2-2.5). The recent transthoracic echocardiography (TTE) done 4 month ago confirmed normal left ventricular systolic function [ejection fraction (EF): 69%] and well functioning of prosthetic mitral valve with mild pulmonary hypertension [right ventricle systolic pressure (RVSP) = 35 mmHg] and mild tricuspid regurgitation. On physical examination, she was acutely ill looking, diaphoretic and tachypneic. Her vital signs were as follows; blood pressure 69/51 mmHg, pulse rate 130/min, body temperature 36.7 with respiratory rate 35 breath/min. Her jugular vein was prominently engorged. On auscultation, audible mitral valve click with grade 4/6 pansystolic murmur was noted. Her electrocardiogram showed atrial fibrillation with rate of 130-140 beats/min. Chest X-ray revealed acute pulmonary edema with aggravated cardiomegaly (). Complete blood count showed white blood cell count of 9820/µL, hemoglobin of 9.8 g/dL, and platelet of 386000/µL. Other labs showed elevated creatinine (1.12 mg/dL, estimated glomerular filtration rate 50 mL/min/1.73) and slightly elevated cardiac enzymes (Creatine Kinase 555 IU/L, Creatine Kinase-MB 22.29 IU/L, Troponin T 0.016 ng/mL) with elevated N-terminal prohormone of brain natriuretic peptide level of 832 pg/mL. C-reactive protein level remained in normal range of 1.13 mg/L. Prothrombin time was 1.92. Arterial blood gas analysis showed oxygen pressure of 97 mmHg, carbon dioxide pressure of 27.4 mmHg, with pH of 7.353 with oxygen mask of 10 L.\nAfter central line through right jugular vein was inserted, central venous pressure was 1 mmHg. Dobutamine and dopamine infusion were started 10 µg/kg/min respectively. The patient was intubated as she became intolerably tachypneic and progressively hypoxic.\nTo evaluate the cause of the shock and acute decompensated heart failure, bed side TTE was performed and revealed normal sized left ventricle (end diastolic dimension: 44 mm) and hyperdynamic left ventricular systolic function (EF: 80%) without regional wall motion abnormality. Moderate tricuspid regurgitation (Grade III) and severe pulmonary hypertension (right ventricular systolic pressure 75 mmHg) with plethora of inferior vena cava were demonstrated. On two-dimensional (2D) echocardiogram, there was suspicious finding of single prosthetic mitral leaflet, but details of the mitral leaflet morphology and Color Doppler were not sufficient for evaluating the prosthetic mitral valve function due to tachycardia and poor echo window. However, elevated mean diastolic pressure gradient (10 mmHg) across the prosthetic mitral valve without prolongation of pressure half time (54 ms) and low velocity of mitral regurgitation (MR, 4 m/s), and rapid declined in MR velocity suggested existence of severe MR ().\nThe diagnosis of acute severe MR due to escape of prosthetic valve leaflet with embolization was made and the patient immediately went through emergency operation to surgically correct dysfunctions of previously replaced mitral valve. The incision was made along the previous operation scar. When mitral valve was exposed, there was one leaflet missing without evidence of paravalvular dehiscence and pannus or thrombus formation (). The previous mechanical valve was removed and replaced with a 29 mm St. Jude Epic tissue valve (St. Jude Medical, St. Paul, MN, USA). After five hours of the surgery, her vital signs were stabilized. TTE after the surgery demonstrated well functioning bioprosthetic mitral valve with decreased tricuspid regurgitation (Grade I) and resolution of pulmonary hypertension (RVSP 39 mmHg).\nIn an attempt to localize the missing leaflet, computed tomography (CT) was done, and a plate like metallic density in infra-renal abdominal aorta was noted (). The remaining fragment of leaflet in infra renal abdominal artery was removed 11 days after bioprosthetic valve replacement. It was placed 2 cm above common iliac artery bifurcation. The abdominal aorta was vertically dissected 7 cm, and the fragment was safely removed (). The patient developed mild fever after the surgery but recovered well and was discharged 37 days after the surgery.