Case Description
A 63-year-old man, who underwent CABG 10 years ago, was admitted to our hospital with chief complaints of dyspnea and chest pain. The transthoracic echocardiography showed aortic valve area of 0.66 cm2, transvalvular peak velocity of 3.4 m/sec, mean transvalvular pressure gradient of 28 mmHg, and left ventricular ejection fraction of 44%, and he was diagnosed as severe aortic valve stenosis. In the previous CABG, the right and left ITAs were anastomosed to the anterior descending artery diagonal artery, respectively. The radial artery was utilized as Y-graft and anastomosed to the posterior lateral and descending branches sequentially. The computed tomography imaging revealed that right ITA crossed over the ascending aorta (Fig.1). The right ITA appeared to be heavily adherent to the sternum (Fig.2). The coronary angiography showed the native left and right coronary arteries were all occluded proximally while all grafts were patent. Moreover, the right ventricular branches were not visualized even from the graft (Fig. 3A, 3B). We decided to do surgical AVR with right anterior thoracotomy. TAVR was not selected since the patient was young enough and had a long life expectancy, surgical AVR seemed appropriate considering the durability of the prosthetic valve.
A 7-cm skin incision was placed at the third right intercostal space, and the ascending aorta was exposed. The cardiopulmonary bypass (CPB) was established between the right axillary artery and the right femoral vein. The bilateral ITA grafts were neither touched nor clamped. After ventricular fibrillation induced by systemic cooling, the aorta was cross clamped. Potassium was administered at the dose of 40 mEq via the CPB. The potassium level elevated to 8.7 mEq/dL and cardiac arrest was obtained. We maintained the patient’s body temperature deep enough at 19 degrees Celsius. Additional 40 mEq potassium was administered twice, targeting potassium level 7.0 to 8.0 mEq/dL. A 21 mm Magna Ease (Edwards Lifescience Corporation, Irvine, CA, USA) was implanted. The potassium level was normalized with administration of glucose and insulin and extracorporeal ultrafiltation method during CPB. After rewarming, the aorta was de-clamped. The CPB was successfully weaned off. The postoperative course was uneventful and the patient was discharged on the postoperative Day 18 after rehabilitation. Two years after the operation, follow-up transthoracic echocardiography showed an improved ejection fraction of 54%, and no para-valvular leakage.