Discussion

Aims: The pattern of, and specific factors associated with long- term survival have not been evaluated in horses with a strangulating large colon volvulus (LCV). The aims of this study were to provide data on the long-term survival of horses with LCV and to identify pre-, intra- and post operative variables associated with survival. Methods: Clinical data and follow-up information were obtained from horses with a strangulating LCV (>360degrees) undergoing general anaesthesia at the Philip Leverhulme Equine Hospital between 1 January 2001 and 31 December 2010. Two multivariable Cox proportional hazards models for post operative survival time were developed: Model 1 included all horses and evaluated preoperative variables and Model 2 included horses that survived anaesthesia and evaluated pre-, intra- and post operative variables. Results: The study population comprised of 116 horses. Eighty-nine horses (76.6%) survived general anaesthesia. Of these, the percentage that survived until discharge, to one year, and to 2 years was 70.7%, 48.3% and 33.7%, respectively. Median survival time for horses that survived general anaesthesia was 365 days. In Model 1 preoperative increasing packed cell volume (PCV) was significantly associated with reduced post operative survival. In Model 2, abnormal serosal colour intraoperatively, increasing heart rate at 48 h post operatively and colic during post operative hospitalisation were all significantly associated with reduced post operative survival. Conclusions and practical significance: Survival time in horses with a LCV was associated with preoperative PCV, serosal colour, heart rate at 48 h post operatively, and colic during post operative hospitalisation. This study provides evidence based information on the long-term survival of horses with LCV and identifies parameters that may assist decision-making by clinicians and owners. Acknowledgements: The Horserace Betting Levy Board funds Joanna Suthers' clinical scholarship in surgery and epidemiology.