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.