BACKGROUND The aim was to analyze IAP changes and the relationships between IAP, CVP, and brain venous blood pressure, which are still unknown, in patients undergoing coronary artery bypass grafting (CABG) with extracorporeal circulation. METHODS Twenty-five male patients (aged 53-67 years) underwent CABG under general anesthesia with normovolemic hemodilution. IAPs were measured in the urinary bladder, CVP by left internal jugular vein cannulation, and brain venous blood pressure by retrograde cannulation of the right jugular vein bulb (JVP, jugular vein pressure) at seven time-points: 1) after induction of anesthesia before the operation, 2) during internal thoracic artery preparation, 3) 10 minutes after heart-lung machine disconnection, 4) after procedure completion, before sending the patient to the intensive postoperative care unit, 5) one hour after the procedure, 6) 6 hours after the procedure, and 7) 18 hours after the procedure. RESULTS IAP increased from points 3 to 6. CVP increased from points 3, 4, and 5 and decreased at point 7. Similar changes were noted in JVP. There were significant correlations between IAP and CVP at points 1, 2, 3, 4, and 5, IAP and JVP at points 3, 4, and 5, and CVP and JVP at all points. The overall analysis showed correlations between IAP and CVP and JVP and very strong correlation between CVP and JVP. CONCLUSIONS 1) CABG with extracorporeal circulation resulted in increases in IAP, CVP, and brain venous blood pressure. 2) The changes in CVP and brain venous blood pressure correlated with intra-abdominal pressure.