Risk factor analysis for nonocclusive mesenteric ischemia following cardiac surgery A case-control study

Although rare, postcardiac surgery nonocclusive mesenteric ischemia (NOMI) is a life-threatening condition. Identifying the risk factors for NOMI during immediate postoperative period may help early detection and intervention, which leads to improved clinical outcomes. The objective of this study was to identify the clinical features and risk factors of NOMI for prognosis identification after cardiac surgery, focusing on immediate postoperative parameters. Among 9445 patients who underwent cardiac surgery over a span of 9 years, 40 NOMI cases (0.4%) requiring surgical interventions were reviewed. Suspected NOMI was diagnosed by sigmoidoscopy or computed tomography. To identify the risk factors, a control group (case: control=1:3 ratio) was randomly selected and compared using logistic regression models. NOMI was diagnosed after a mean of 8.1 +/- 9.6 days following cardiac surgery. Age (odds ratio: 1.16, 95% confidence interval: 1.08-1.25, P<.001), total vasoactive-inotropic score (VIS), and the maximal lactate level at postoperative day 0 (1.003, [1.001-1.005], P=.012), (1.23, [1.04-1.44], P=.011) were shown as risk factors. NOMI cases showed persistent hyperlactatemia without washout during the first 48 hours (P=.04). Thirty-four cases underwent exploratory laparotomy within a median of 10(2-356) hours after the diagnosis, but only 17 patients (42.5%) survived. Compared with survivors, nonsurvivors showed higher total VIS at diagnosis, higher lactate levels during the first 24 hours postoperatively, and more frequently required extensive bowel resection (P<.05). Old age, postoperative high-dose vasoactive-inotropic use, and persistent high lactate level during the first 24 hours postsurgery were identified as risk factors for NOMI. Lactic acidosis and necrotic-bowel extent at surgical exploration were associated with poor survival.