Pathologic Features of Colon Ischemia (CI) and Their Relationship to Disease Distribution and Outcome: 182

Introduction: CI is a common cause of “colitis” in elderly pts. Isolated right CI (IRCI) is an important entity as it has been associated with poorer outcomes than any other pattern of involvement including isolated left colon ischemia (ILCI). To our knowledge, there has been no study on the relationship of pathological features of CI and disease distribution or outcome. The aims were (1) to compare pathological features among those with IRCI vs. ILCI and; (2) to determine if there is any relationship between pathological features of CI and clinical outcomes. Methods: A retrospective, multi-centered chart review of pts with a diagnosis of CI at Montefiore Medical Center (01/2005 to 07/2015), and Yale-New Haven Hospital (01/2005 to 06/2010) was performed to determine the relationship between pathological features of CI and disease distribution or clinical outcomes. Inclusion criteria were: (1) clinical presentation; (2) colonoscopic findings; and (3) colonic pathology consistent with CI. Pts were excluded if they did not meet all 3 inclusion criteria and if their clinical presentation could be explained by any alternate disease process. IRCI was defined as disease isolated to the cecum, ascending colon and/or hepatic flexure; ILCI was defined as disease isolated to the splenic flexure, descending colon, sigmoid colon and/or rectum. Poor outcome was defined by mortality and/or colectomy at 30 days. Results: 446 pts were included. 115 had ILCI (25.7%), 48 had IRCI (10.8%) and 283 did not have a complete colonoscopy or had a different pattern of disease (63.4%). 64 of 446 pts experienced a poor outcome (14.3). Pts with IRCI were more likely than pts with ILCI to exhibit necrosis (25.0% vs 9.6%; P=<0.01), cryptitis or crypt abscess (25.0% vs 8.7%; P=<0.01) and inflammation (68.8% vs 50.4%; P=0.03) (Table 1). Pts with poor outcomes were more likely to exhibit necrosis (65.6% vs 12.8%; P=<0.01) and capillary fibrin thrombi (9.4% vs 2.6%; P=<0.01) and less likely to exhibit fibrosis (10.9% vs 28.5%; P=<0.01) and epithelial changes (3.2% vs 23.1%; P=<0.01) on biopsy compared with those without poor outcomes (Table 2).Table: Table. Relationship Between Pathologic Findings and Distribution of Ischemic InjuryTable: Table. Relationship between Pathologic Findings and Clinical Outcome of Colon IschemiaConclusion: In our cohort of pts with CI, those with IRCI were more likely to have pathological findings of necrosis, cryptitis/crypt abscess, and inflammation compared with pts who had ILCI. Furthermore, this study suggests that patients with pathologic findings of necrosis or capillary fibrin thrombi on biopsy may be at a high risk for poor outcome.