Abstract
Background : Aortic valve stenosis may be complicated by atherosclerotic lesions in the ascending aorta, which may cause cerebral infarction due to intraoperative dispersion of atheromas. We describe herein a safe aortic cross-clamping technique after removal of the sclerotic lesion in the ascending aorta during short-term unilateral selective cerebral perfusion and mild hypothermic circulatory arrest. Methods : From January 2006 to March 2014, a total of 144 patients underwent aortic valve replacement (AVR) for treatment of aortic valve stenosis. Patients who required ascending aorta replacement surgery, had infective endocarditis, or required emergency surgery were excluded. Five patients underwent AVR using unilateral selective cerebral perfusion and mild hypothermic circulatory arrest due to the presence of atherosclerotic plaques or severe calcification of the ascending aorta (Compromised Aorta group), and 139 patients underwent AVR using ascending aortic perfusion and clamping (Control group). Cardiopulmonary bypass using the right axillary and femoral arteries was started and cooled to a pharyngeal temperature of 34°C in the Compromised Aorta group. During hypothermic circulatory arrest, the brachiocephalic artery was clamped and unilateral selective cerebral perfusion was administered from the right axillary artery. The perfusion volume was adjusted to 500 to 800 ml while using the cerebral oxygen saturation monitor. After transection of the ascending aorta, the atheroma and suture line calcification were removed. A suitable site for cross-clamping was identified under direct vision, and the aorta was carefully cross-clamped. Results : The patients in the Compromised Aorta group required a mean circulatory arrest period of 3.8 min (range, 3.0-5.5 min). The mean minimum value of the left-side cerebral oxygen saturation was 52.0% (range, 45-58%). No patients in the Compromised Aorta group died or developed cerebral complications (95% confidence interval (CI) 0.000-0.522). Complications in the Control group included in-hospital mortality (3/140, 2.2% ; 95%CI : 0.003-0.046 ; p=0.899), stroke (2/139, 1.4% ; p=0.932), transient neurologic deficits (4/139, 2.9% ; p=0.867), and total cerebral complications (6/139, 4.3% ; 95%CI : 0.009-0.077 ; p=0.806). Additionally, there were no significant differences between the Compromised Aorta and Control groups in the operative time (345.8±71.8 vs. 333.6±85.4 min, respectively ; p=0.754), cardiopulmonary bypass time (196.4±63.6 vs. 199.2±50.0 min, respectively ; p=0.902), and aortic cross-clamp time (132.0±44.1 vs. 124.8±36.3 min, respectively ; p=0.666). Conclusion : Short-term unilateral selective cerebral perfusion and mild hypothermic circulatory arrest is a safe strategy in patients undergoing AVR with a severely atherosclerotic aorta. The outcomes of this strategy were equivalent to those in the Control group, which had fewer atherosclerotic lesions in the ascending aorta.
