In all cases, surgery was performed under general anesthesia with tracheal intubation and cardiopulmonary bypass (CPB). During surgery arterial pressures at the upper and lower limbs were monitored. An esophageal echocardiography probe was placed routinely, and a sternal incision was performed. To establish CPB, the perfusion tube was placed in the right axillary artery and the drainage tube was placed in the superior and inferior vena cava through the right atrium. The CPB flow rate was of 2.4-2.6 L/kg/min. Intermittent cold blood cardioplegia was perfused through the left and right coronary arteries for myocardial protection.