Anatomic patterns, patient characteristics, and clinical outcomes in ischemic colitis: A study of 313 cases supported by histology

Objectives: Previous reports on the anatomic portions of colon involved in cases of supposed ischemic colitis (IC) have been limited by the absence of confirmation of the true nature of the disease. This is the first anatomic study to define the patterns of colon involvement in which only cases with biopsy-proven or-compatible IC and in which the entire colon had been visualized at surgery or at colonoscopy were included. The aims of this study were to re-examine patterns of colonic involvement in IC using only cases in which the diagnosis was biopsy proven or compatible, and to examine the clinical features and outcomes with regard to the segments of colon involved. Methods: A retrospective study was undertaken of patients with IC who were hospitalized at Montefiore Medical Center from 1998 to 2009. Patients were identified using computerized searches of ICD-9 (International Classification of Diseases, ninth revision) codes for colon ischemia, and patterns of colon involvement were then tabulated and categorized into five major groups: right colon, transverse colon, left colon, distal colon, and pancolon involvement. Patterns were classified based on the most proximal location of injury. Major anatomic patterns were then subcategorized into more specific segments of involvement. Only biopsy-proven or-compatible cases of IC in which the entire colon had been visualized at surgery or at colonoscopy were used in this study. Results: A total of 313 cases of biopsy-proven or-compatible IC were identified. Patterns and frequencies of involvement were: right colon, 25.2%; transverse colon, 10.2%; left colon, 32.6%; distal colon, 24.6%; and pancolon, 7.3%. Compared with all other patterns of IC, the right colon pattern was more likely to be associated with coronary artery disease (39.2 vs. 21.4%) or end-stage kidney disease requiring dialysis (20.3 vs. 7.7%), a longer hospitalization (median stay, 10 vs. 6 days), a greater need for surgery (44.3 vs. 11.5%), and the highest mortality rate (20.3 vs. 9%). Patients with a left colon pattern were less likely to be operated upon, and had a shorter length of stay than any other pattern of IC. Hyperthyroidism, stroke, and chronic obstructive pulmonary disease (COPD) were statistically significant independent predictors of mortality. Conclusions: IC is typically a segmental disease, flanked by normal colon on either side of the affected area. Comorbid disease associations and severity of disease as reflected by length of hospitalization, need for surgery, and mortality vary with the segment involved. IC isolated to the right side of the colon is a more severe disease than IC affecting any other segment of colon.