Intra-abdominal hypertension in obese patients undergoing coronary surgery: A prospective observational study

Coronary artery bypass grafting surgery has an increased risk of adverse events in obese patients. This increased risk might be explained in part by an increased intra-abdominal pressure and the development of intra-abdominal hypertension. Therefore, the objective of this study was to investigate the correlation between obesity and intra-abdominal hypertension and to evaluate its possible impact after coronary artery bypass grafting.

A total of 50 consecutive patients scheduled to undergo coronary artery bypass grafting at a single center were selected prospectively before undergoing elective coronary artery bypass grafting. Based on the body mass index, 25 obese (body mass index ≥ 30) patients were matched with 25 control patients. Each patient had intra-abdominal pressure taken at baseline followed by one measurment every 4 hours until 24 hours after coronary artery bypass grafting. The serum markers for liver and kidney functions were collected once a day for 7 days after coronary artery bypass grafting.

Obese patients had a greater (mean ± SD) peak intra-abdominal pressure (15.4 ± 1.6 mm Hg versus 10.6 ± 1.6 mm Hg; P = .011) and mean change of intra-abdominal pressure from baseline (5.1 ± 3.3 mm Hg versus 2.2 ± 2.4 mm Hg; P = .001). The mean abdominal perfusion pressure was less in the obese group (63.0 ± 8.0 mm Hg versus 70.1 ± 11 mm Hg; P = .017). The liver dysfunction, as determined by the Schindl liver function scoring system between the obese and control groups, was not statistically significant (28% vs 8%; P = .066). More patients in the obese group developed renal injury based on the calculated glomerular filtration rate (32% vs 8%; P = .034). Obesity was highly associated with developing intra-abdominal hypertension (odds ratio: 2.99; 95% confidence interval: 1.92-3.53; P < .001).

Obesity is associated with the development of intra-abdominal hypertension after coronary artery bypass grafting. This effect might indirectly impair the renal and liver functions through a decrease in the abdominal perfusion pressure.