Pulse Pressure Variation for Prediction of Fluid Responsiveness in Coronary Artery Disease Patients With Diastolic Dysfunction

Inclusion Criteria: * Patients older than 20 years * scheduled for elective coronary artery bypass grafting * normal diastolic function (E/E' \< 8) or diastolic dysfunction (E/E' \>15) according to preoperative Echocardiographic evaluation Exclusion Criteria: * arrythmia, * reduced left ventricular function (ejection fraction \< 40%) * valvular heart disease requiring concomitant surgical correction * pulmonary hypertension (mean pulmonary arterial pressure ≥30 mm Hg) * peripheral arterial occlusive disease, pulmonary disease (asthma, chronic obstructive pulmonary disease, and lung resection) * end-stage renal disease