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Comparison of survival after surgical or medical treatment in dogs with a congenital portosystemic shunt

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  • 1 Department of Veterinary Medicine, Veterinary School, University of Cambridge, Cambridge, CB3 0ES, England.
  • | 2 Department of Veterinary Medicine, Veterinary School, University of Cambridge, Cambridge, CB3 0ES, England.
  • | 3 Department of Veterinary Medicine, Veterinary School, University of Cambridge, Cambridge, CB3 0ES, England.
  • | 4 Department of Clinical Veterinary Science, School of Veterinary Science, University of Bristol, Langford, Bristol, BS40 5DU, England.
  • | 5 The Shrubbery Veterinary Centre, 65 Perry St, Norhfleet, Kent, DA11 8RD, England.
  • | 6 Section of Veterinary Clinical Studies, School of Agriculture, Food Science & Veterinary Medicine, College of Life Sciences, University Veterinary Hospital, University College Dublin, Belfield, Dublin 4, Ireland.
  • | 7 Section of Veterinary Clinical Studies, School of Agriculture, Food Science & Veterinary Medicine, College of Life Sciences, University Veterinary Hospital, University College Dublin, Belfield, Dublin 4, Ireland.
  • | 8 Department of Clinical Veterinary Science, School of Veterinary Science, University of Bristol, Langford, Bristol, BS40 5DU, England.
  • | 9 Department of Veterinary Medicine, Veterinary School, University of Cambridge, Cambridge, CB3 0ES, England.
  • | 10 Department of Veterinary Medicine, Veterinary School, University of Cambridge, Cambridge, CB3 0ES, England.

Abstract

Objective—To compare survival of dogs with a congenital portosystemic shunt (CPSS) that received medical or surgical treatment.

Design—Prospective cohort study.

Animals—126 client-owned dogs with a single CPSS.

Procedures—Dogs were examined at 1 of 3 referral clinics, and a single CPSS was diagnosed in each. Dogs received medical or surgical treatment without regard to signalment, clinical signs, or results of hematologic or biochemical analysis. Survival data were analyzed via a Cox regression model.

Results—During a median follow-up period of 579 days, 18 of 126 dogs died as a result of CPSS. Dogs treated via surgical intervention survived significantly longer than did those treated medically. Hazard ratio for medical versus surgical treatment of CPSS (for the treatment-only model) was 2.9 (95% confidence interval, 1.1 to 7.2). Age at CPSS diagnosis did not affect survival.

Conclusions and Clinical Relevance—Both medical and surgical treatment can be used to achieve long-term survival of dogs with CPSS, although results of statistical analysis supported the widely held belief that surgery is preferable to medical treatment. However, the study population consisted of dogs at referral clinics, which suggested that efficacy of medical treatment may have been underestimated. Although surgical intervention was associated with a better chance of long-term survival, medical management provided an acceptable first-line option. Age at examination did not affect survival, which implied that early surgical intervention was not essential. Dogs with CPSS that do not achieve acceptable resolution with medical treatment can subsequently be treated surgically.

Abstract

Objective—To compare survival of dogs with a congenital portosystemic shunt (CPSS) that received medical or surgical treatment.

Design—Prospective cohort study.

Animals—126 client-owned dogs with a single CPSS.

Procedures—Dogs were examined at 1 of 3 referral clinics, and a single CPSS was diagnosed in each. Dogs received medical or surgical treatment without regard to signalment, clinical signs, or results of hematologic or biochemical analysis. Survival data were analyzed via a Cox regression model.

Results—During a median follow-up period of 579 days, 18 of 126 dogs died as a result of CPSS. Dogs treated via surgical intervention survived significantly longer than did those treated medically. Hazard ratio for medical versus surgical treatment of CPSS (for the treatment-only model) was 2.9 (95% confidence interval, 1.1 to 7.2). Age at CPSS diagnosis did not affect survival.

Conclusions and Clinical Relevance—Both medical and surgical treatment can be used to achieve long-term survival of dogs with CPSS, although results of statistical analysis supported the widely held belief that surgery is preferable to medical treatment. However, the study population consisted of dogs at referral clinics, which suggested that efficacy of medical treatment may have been underestimated. Although surgical intervention was associated with a better chance of long-term survival, medical management provided an acceptable first-line option. Age at examination did not affect survival, which implied that early surgical intervention was not essential. Dogs with CPSS that do not achieve acceptable resolution with medical treatment can subsequently be treated surgically.

Contributor Notes

Dr. Greenhalgh's present address is Larkmead Veterinary Group, Ilges Ln, Cholsey, Oxfordshire, OX10 9PA, England.

Dr. Dunning's present address is Anderson Sturgess Veterinary Specialists, The Granary, Burnstead Barns, Poles Ln, Hursley, Winchester, Hampshire, SO21 2LL, England.

Dr. Goodfellow's present address is IGF Group, Molecular Oncology Laboratories, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, England.

Dr. Kelman's present address is 2/8 Hubert Rd, Maylands, Perth, WA 6051, Australia.

Support for Dr. Watson was provided by the Bunning endowment and the Iams Company.

Support for Dr. Freitag was provided by Hill's Pet Nutrition Limited.

Address correspondence to Dr. Jeffery (ndj1000@cam.ac.uk).