Written patient consent was obtained, and our institutional ethical committee approved the publication of this case report.
A 56-year-old male (167 cm, 55.6 kg), who had undergone a David operation for type-A acute aortic dissection 7 months ago, was scheduled for a Bentall operation for a pseudo aortic aneurysm and perivascular abscess. The aneurysm had increased from 60 to 76 mm in 3 months before the operation and some blood flow was observed inside the aneurysm. The entry to the aneurysm was identified at the anastomosis with artificial blood vessels above the aortic valve. Blood flow showed a to-and-fro pattern between the left ventricle and the aneurysm. The blood flow from the aneurysm to the left ventricle during diastole was similar to aortic regurgitation (AR), and the degree of regurgitation was moderate to severe. Furthermore, we also found abnormal blood flow from the aneurysm to the main pulmonary artery. Other preoperative transthoracic echocardiography findings included normal systolic function, grade II diastolic function (E/A: pseudo-normalization pattern), mild to moderate tricuspid regurgitation, and moderate pulmonary hypertension. Three months before the operation, he developed heart failure due to perivascular abscess. His preoperative chest X-ray revealed cardiac dilatation (CTR 60%) and bilateral pleural effusion. The electrocardiogram showed sinus tachycardia and complete right bundle branch block. Routine laboratory data were within normal range except hemoglobin 10.4 g dL−1, platelet 281,000 μL−1, fibrinogen 460 mg dL−1, WBC 6200 μL−1, CRP 6.78 mg dL−1, brain natriuretic peptide (BNP) 1860 pg dL−1, and creatinine 1.25 mg dL−1. Coronary computed tomography showed no findings suggesting coronary stenosis. Thoracic computed tomography demonstrated the following: extensive adhesion between the aneurysm and the sternum, and angiectopia of the right subclavian artery originating from the distal aortic arch (Fig. 1).
We discussed intraoperative management of the present case at a preoperative conference of anesthesiologists and cardiac surgeons and determined the following algorithm: (1) A left anterolateral small thoracotomy is performed and a left ventricle venting tube is placed to avoid left ventricle distension, because the patient has severe aortic regurgitation. (2) Nifekalant is administered slowly to prevent VF associated with cooling. (3) Institution of full-flow cardiopulmonary bypass (CPB) is done through the femoral vessels or combination of the right axial artery and femoral vessels. (4) Once CPB is established, cooling is initiated by monitoring the bladder temperature and the patient is cooled to 27 °C. (5) At the target bladder temperature of 27 °C, resternotomy is performed. (6) The temperature is maintained until the complete division of the sternum to prevent VF and to conserve contractility. (7) After completing dissection of retrosternal adhesions, aortic cross-clamping is performed, the pseudoaneurysm was incised, and cardioplegia was delivered selectively in the coronary ostia.
General anesthesia was induced with midazolam 5 mg, fentanyl 0.2 mg, and vecuronium 8 mg and maintained with sevoflurane, propofol, remifentanil, and vecuronium. The trachea was intubated with a 37-Fr left double-lumen tube for one-lung ventilation. A percutaneous DC pad was attached on his chest prophylactically. After induction of anesthesia, the left radial and femoral arteries were cannulated for arterial blood pressure monitoring. A central venous catheter and a pulmonary artery catheter were placed through the right internal jugular vein. A transesophageal echocardiography (TEE) probe was inserted for intraoperative cardiac monitoring. Regional cerebral oxygen saturation (rSO2) was measured with near-infrared spectroscopy. We detected the oxygen step-up in the pulmonary artery and calculated that pulmonary flow/systemic flow (Qp/Qs) was 1.7.
At first, we administered nifekalant, 10 mg, intravenously. Then, the vent tube was inserted into the left ventricle with a small left thoracotomy under one-lung ventilation. Extracorporeal circulation was established through the cannulation from the right femoral artery and vein, which provided full-flow CPB. Then, cooling was initiated by monitoring the bladder temperature. Resternotomy was initiated after the patient was cooled to 27 °C. The strong adhesion between the sternum and the aortic artery was completely exfoliated without damaging the pseudoaneurysm. Severe bradycardia, QT prolongation, and premature ventricular contraction (PVC) were observed, but VF did not occur under 27 °C (Fig. 2). Bilateral rSO2 decreased with progression of bradycardia (left rSO2 54 to 36% and right rSO2 51 to 35%). Although we increased the blood flow of CPB and transfused red blood cell, the values remained low in 30s. The values continued to be 30s until the aortic clamping and after then improved to 40s. After exposure of the aortic clamp site was completed, we re-started cooling and clamped the aorta at the distal side of the aneurysm and induced asystole by selective cardioplegia. The Bentall operation scheduled was performed without any problem. Weaning from CPB was uneventful and the patient was transported to ICU without extubation. His trachea was extubated on the 5th postoperative day and he had no neurological sequelae.