Use of pelvic flexure biopsy scores to predict short-term survival after large colon volvulus.

OBJECTIVE To (1) determine if histologic scores of pelvic flexure biopsies can predict short-term survival in horses with large colon volvulus (LCV) and (2) identify clinical variables predictive of short-term survival. STUDY DESIGN Case series. ANIMALS Horses (n = 28) with LCV (≥ 360°). METHODS Medical records (January 2000-February 2008) of 28 horses were reviewed and clinical data recorded. Pelvic flexure biopsies were reviewed by 2 board-certified veterinary pathologists, unaware of clinical history and outcome, using 2 scoring systems. Exact logistic regression analysis was used to determine the relationship between histopathology scores (tissue viability), clinical data, and short-term survival (hospital discharge). RESULTS Twenty-four horses (86%) survived to hospital discharge. Using a similar cutoff, neither scoring system was capable of predicting short-term survival. One scoring system failed to correctly predict clinical outcome in 5/25 horses (20%) and the other failed in 6/28 horses (22.4%). Heart rate (at admission and 24 hours after surgery) and packed cell volume 24 hours after surgery were significantly associated with short-term survival. CONCLUSION Histopathologic evaluation of pelvic flexure biopsies did not accurately predict short-term survival in a significant proportion of horses with LCV in this study.