Long-term survival and quality of life in dogs with clinical signs associated with a congenital portosystemic shunt after surgical or medical treatment

• Autores: Stephen N. Greenhalgh
• Localización: JAVMA: Journal of the American Veterinary Medical Association, ISSN-e 0003-1488, Vol. 245, Nº. 5, 2014, págs. 527-533
• Idioma: inglés
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• Resumen

  • Objective—To compare long-term survival and quality of life data in dogs with clinical signs associated with a congenital portosystemic shunt (CPSS) that underwent medical or surgical treatment.

    Design—Prospective cohort study.

    Animals—124 client-owned dogs with CPSS.

    Procedures—Dogs received medical or surgical treatment without regard to signalment, clinical signs, or clinicopathologic results. Survival data were analyzed with a Cox regression model. Quality of life information, obtained from owner questionnaires, included frequency of CPSS-associated clinical signs (from which a clinical score was derived), whether owners considered their dog normal, and (for surgically treated dogs) any ongoing medical treatment for CPSS. A Mann-Whitney U test was used to compare mean clinical score data between surgically and medically managed dogs during predetermined follow-up intervals.

    Results—97 dogs underwent surgical treatment; 27 were managed medically. Median follow-up time for all dogs was 1,936 days. Forty-five dogs (24 medically managed and 21 surgically managed) died or were euthanized during the follow-up period. Survival rate was significantly improved in dogs that underwent surgical treatment (hazard ratio, 8.11; 95% CI, 4.20 to 15.66) than in those treated medically for CPSS. Neither age at diagnosis nor shunt type affected survival rate. Frequency of clinical signs was lower in surgically versus medically managed dogs for all follow-up intervals, with a significant difference between groups at 4 to 7 years after study entry.

    Conclusions and Clinical Relevance—Surgical treatment of CPSS in dogs resulted in significantly improved survival rate and lower frequency of ongoing clinical signs, compared with medical management. Age at diagnosis did not affect survival rate and should not influence treatment choice.

    Congenital portosystemic shunts in dogs result from persistent embryonic or aberrant vasculature that permits blood from the gastrointestinal tract to bypass the liver and enter the systemic circulation. Such vessels may lie within or outside of the liver parenchyma and are referred to as intrahepatic or extrahepatic, respectively. Large-breed dogs tend to have intrahepatic CPSS, whereas extrahepatic CPSS are more prevalent in small-breed dogs.1,2 Purebred dogs are more likely to have CPSS than are mixed-breed dogs.3,4 Congenital portosystemic shunts are distinct from acquired portosystemic shunts, which are generally multiple and arise secondary to increased portal pressure. Congenital portosystemic shunts can result in a variety of clinical signs, predominantly affecting the neurologic, gastrointestinal, and urinary systems.5,6 Congenital portosystemic shunts can be managed surgically, and various techniques are available to achieve full or partial occlusion of the shunting vessel.7–15 The condition can also be treated medically with a combination of antimicrobial delivery, synthetic disaccharide administration, and dietary management.7,16,17 Convincing evidence for the optimal management modality is lacking.18 Furthermore, published long-term survival and quality of life data are limited, particularly for medically managed veterinary patients. It has been assumed that surgical correction is the treatment of choice because occlusion of the shunting vessel has the theoretical potential to restore normal physiology, and even partial occlusion can resolve clinical signs.19,20 The proposed benefits of surgery must be offset against the risks of perioperative death and shunt persistence leading to ongoing clinical signs, as well as the possibility that multiple acquired shunts may develop as a consequence of increased portal pressure.6,13,14,18 Potential disadvantages of medical management include the persistence of abnormal physiology, failure to resolve or control clinical signs adequately, and the need for lifelong medication, dietary manipulation, or both.

    We hypothesized that survival rate and quality of life (as assessed by persistence of clinical signs) of dogs with clinical signs associated with CPSS would be affected by the choice of medical versus surgical management. In 2010, we reported the initial results of a multicenter, prospective cohort study21 comparing survival time in dogs with CPSS managed surgically or medically. Findings suggested that, although dogs with CPSS can survive long term with surgical or medical management, surgical intervention was associated with a significantly improved probability of survival to the end of the study period. The purpose of the study reported here was to determine long-term survival data for the same cohort of dogs with CPSS21 and to evaluate short-, medium-, and long-term quality of life as assessed by their owners.