7114 Can colonoscopy diagnose transmural ischaemic colitis after abdominal aortic surgery. an evidence based approach.

Abstract

Clinical diagnosis and decisions are often based on individiual expertise and tradition. The use of current best available external evidence from basic or clinical research is often impeded due to several reasons, e.g. lack of time for clinicians to read and keep up to date, but also an inefficient approach to clinical learning. Evidence based medicine seeks to combine the best external evidence from systematic research with individual clinical experience. Ischaemic colitis is a well known and potentially fatal complication to aortic surgery. Once the diagnosis is suspected, colonoscopy is the method of choice. However, we recently encountered two cases in which senior gastroenterologists failed to reach the diagnosis of transmural ischaemic colitis. This made us question the diagnostic validity of colonoscopy after aortic surgery, which in turn led us to establish an evidence based conference to answer the following question: is colonoscopy diagnostic for ischaemic colitis? Method: A search for literature made by all doctors in the department. It was decided, that emphasis should be put on prospective controlled trials, preferentially randomised, and that editorials, ordinary reviews and case reports should be left out. A review of the literature was performed according to evidence based principles. Results: No randomised studies were found.We identified 7 prospective, not all consecutive, reports focusing on endoscopy and ischaemic colitis after aortic surgery. In these reports, the incidence of ischaemic colitis found at endoscopy, ranged from 3-9% following elective operations to 18-60% following surgery for ruptured aneurysms. Endoscopy may disclose ischaemic colitis, but can not separate transmural from the clinical less important mucosal ischaemia. In none of the identified prospective series had endoscopy any impact on mortality, contradicting recommendations based on casuistic reports. None of the participants in the evidence based conference had identified all reports. Conclusion: The value of endoscopy as a single procedure in identifying transmural ischaemic colitis after abdominal aortic surgery is limited. A diagnostic modality, other than laparatomy, to distinguish mucosal from transmural ischaemia needs to be developed. The evidence based conference was an inspiring teaching modality, and illustrated for the participants the difficulty in performing a targeted literature search.