Hospital Research Ethics Committee approval will be obtained. Data of all patients who had undergone elective off pump CABG will be obtained from hospital record section. Patients who had undergone emergency CABG surgeries, combined surgeries like CABG with MVR or CABG with AVR and on pump CABG are excluded from study. Preoperative investigations like CBC, renal functions, coagulation profile etc. will be collected from hospital laboratory reports.

Pre-operative parameters analyzed will include age, sex, body surface area (BSA), left main coronary artery stenosis >50%, antiplatelet medications within 7 days before operation, pre-operative heparin therapy, recent history of myocardial infarction (within 6 months), ejection fraction , previous cardiac surgery, chronic renal failure, cerebrovascular disease, antifibrinolytic drugs and last preoperative Hct. Intraoperative data consisted of number of distal anastomoses performed, use of internal mammary arteries (IMA), and lowest intraoperative Hct documented.

The primary endpoints of interest will be packed red blood cell transfusions, reoperation rate for bleeding or cardiac tamponade and total postoperative chest tube drainage. Only intraoperative and postoperative homologous packed RBC transfusions will be recorded.