218 Septal Myectomy and Left Atrial-to-Left Ventricle Valved Conduit for Severe Calcific Mitral Stenosis and Obstructive Hypertrophic Cardiomyopathy: A Case Report

Mitral annular calcification with severe mitral valve (MV) stenosis can be difficult to treat with conventional MV replacement. Annular decalcification can cause atrioventricular groove disruption and bleeding. An alternative is to bypass the narrowed MV using a valved left-atrial-to-left-ventricle conduit. A 48-year-old gentleman with obstructive-hypertrophic cardiomyopathy and severe calcific MV stenosis presented with progressive dyspnea, syncope, and fatigue. Medical history included hypertension, dialysis dependent ESRD, chronic-AF, pulmonary-hypertension, and NSVT. A grade III/IV mid-systolic murmur was audible at the LSE, and a grade II/IV mid-diastolic rumble. Echocardiography showed sigmoid septum with maximum thickness of 24-mm, severe calcific MV-inflow obstruction (MVA 0.87 cm2, mean gradient 15-mmHg, heart rate 60-bpm), and midventricular LVOT obstruction (resting gradient 96-mmHg). Because of NYHA class III symptoms, surgery was performed with plans for MV-bypass using a valved-conduit and midventricular myectomy. Following institution of CPB and cardioplegic arrest, the LAA was excised and a 26-mm Hemashield graft was beveled and sewn into the atriotomy. An anterolateral ventriculotomy was made near the apex of the heart and an extensive midventricular myectomy was performed through the incision. A 25-mm Hancock-II bioprosthesis was sewn into the conduit. Distal end of the conduit was beveled and anastomosed to the ventriculotomy. Postoperatively, median native-MV gradient reduced to 7-mmHg (heart rate 86-bpm). Recovery was uneventful. He was dismissed on postoperative-day 8 and continues to do well 5-months later. MV-bypass using a valved LA-to-LV conduit is safe alternative to conventional MVR for relief of severe MS with MAC, particularly in patients with oHCM who require midventricular myectomy.