Inferior mesenteric artery reimplantation does not guarantee colon viability in aortic surgery

BACKGROUND: Reimplantation of the inferior mesenteric artery (IMA) at the time of aortic surgery has been advocated to prevent colon ischemia in patients deemed to have inadequate perfusion of the left colon. The purpose of this study was to determine whether IMA reimplantation is globally protective against colon necrosis. STUDY DESIGN: We reviewed the medical records of all patients who were diagnosed with colon ischemia after aortic surgery during a 10-year period. Cases were indexed from the institution's operative database and from the vascular morbidity and mortality registry. RESULTS: Ten patients (eight men, two women; mean age 71 ± 9 years) were identified during the study period. Five patients (50%) underwent successful IMA reimplantation for inadequate Doppler signals on the antimesenteric border of the sigmoid colon. Five other patients (50%) did not undergo IMA reimplantation because they were deemed to have adequate colon perfusion. Transmural colon necrosis occurred in 6 of the 10 study patients, 4 of whom had IMA reimplantation. Five of the six patients had intraoperative hypotension. Three of the four patients with colon ischemia presenting less than 24 hours after aortic revascularization survived (mortality 25%), but both patients with late colon ischemia died of multisystem organ failure (mortality 100%). Four patients developed mucosal ischemia and did not undergo colectomy. Only one of these had IMA reimplantarion. Colon ischemia was detected more than 1 week postoperatively in three patients. All four patients were treated with supportive therapy and antibiotics, and all four survived to discharge after a mean length of stay of 14 ± 10 days. CONCLUSIONS: These data show that IMA reimplantation does not ensure colon viability in aortic surgery. Transmural colon necrosis tends to present sooner than mucosal ischemia and may be attributable to nonanatomic variables such as intraoperative hypotension. Although transmural necrosis is a highly morbid complication after aortic surgery, timely colectomy may lead to survival in some patients.