Surgical technique:
Proximal right brachial artery cannulation with unilateral ASCP and 28°C hypothermia was used in all patients 9. Back bleeding from left carotid artery was always controlled to test the adequacy of collateral flow from the right carotid system. During ASCP 700-800 ml/min (10 ml/kg/min) blood flow was provided with cerebral NIRS monitoring (right and left frontal regions). If ASCP period was anticipated to last longer than 40-45 minute or a difference between right and left cerebral NIRS values with more than 20% drop from the baseline was observed bilateral perfusion was employed through a separate left carotid artery cannula which was necessary in 3 patients. For spinal cord rSO2 NIRS monitoring pallets were placed at the skin over spinous process of 5th and 10th thoracic vertebrae level. Baseline measurement of NIRS value (rSO2) were done before anesthetic induction and then followed by 5 periods of evaluation; after anesthetic induction, upon commencement of cardiopulmonary bypass (CPB), after cross clamp application, at the end of ASCP period and after conclusion of CPB (SOMANETICS INVOSTM 7100 Cerebral/Somatic Oximeter, Medtronic).