4.4.4 Data collection Preoperative data: Demographic, morphological and clinical descriptors including age, gender, body mass index (BMI), body surface area (BSA) co-morbidity, Euroscore risk-stratification, medication, etc. will be recorded. Preoperative laboratory analysis will include complete blood count, coagulation profile, serum creatinine levels and creatinine clearance, liver function test and arterial blood gases test and serology for HIV,HCV,HBC. Compatible with our routine policy, all patients will undergo preoperative echocardiography, coronary angiography, chest x-ray, lung function tests (spirometry) and carotid artery duplex study.