Abdominal perfusion pressure and coronary arterial perfusion pressure in patients undergoing coronary artery bypass graft surgery.

Abdominal perfusion pressure (APP) is defined as the difference between the mean arterial pressure and the intra-abdominal pressure (IAP). IAP elevation results in various side effects, including a decrease in coronary arterial perfusion pressure (CoPP). The present study analyzed the relationship between APP and CoPP in patients undergoing extracorporeal circulation (ECC). The patient population selected for the present study comprised 45 adult patients with a mean (+/- SD) age of 65.9+/-7.21 years (range 42 to 80 years), undergoing coronary artery bypass grafting with ECC and normovolemic hemodilution under general anesthesia. CoPP was measured as the difference between mean arterial pressure and pulmonary capillary wedge pressure. APP and CoPP were measured at seven time points (TPs): before surgery after the induction of anesthesia (TP1), during internal mammary artery preparation (TP2), 10 min after the heart-lung machine disconnection (TP3), after completion of the procedure but before sending the patient to the postoperative intensive care unit (TP4), 1 h after surgery (TP5), 6 h after surgery (TP6) and 18 h after the procedure (TP7). TP1 was considered to be the baseline value. IAP increased from TP3 to TP7; APP decreased at TP3 and TP4; there were no significant changes in CoPP. Significant correlations between APP and CoPP were observed at all TPs. Moreover, IAP correlated with CoPP at TP2 and TP4. Additionally, there was a strong overall correlation between APP and CoPP (P<0.001, r=0.9598). The present study arrived at two major conclusions: that ECC resulted in IAP elevation and that APP was strongly correlated with CoPP.