Lifetime survival: surgical versus medical management of portosystemic vascular anomalies in dogs with and without copper-restricted liver diets (1980-2015).

Abstract

OBJECTIVE: Investigate lifetime survival of dogs with portosystemic vascular anomalies (PSVA) fed copper (Cu)-restricted liver diets (0.10 to 0.12 mg of Cu/100 kcal, below National Research Council and Association of American Feed Control Officials thresholds) with different managerial strategies (complete ligation, partial ligation, or medical management). METHODS: 377 dogs with extrahepatic PSVA (E-PSVA) and 87 with intrahepatic PSVA (I-PSVA) managed at a single specialty hospital (January 15, 1980, to December 28, 2015) were categorized by managerial strategy and dietary Cu intake (Cu-restricted [0.10 to 0.12 mg of Cu/100 kcal] vs Cu-replete [≥ 0.20 mg of Cu/100 kcal]). Lifetime physical, hematological, and death-associated covariates were inspected for evidence of Cu insufficiency. Survival metrics (last age, survival duration, Kaplan-Meier analytics) were compared. Liver Cu was quantified in 71 of 246 biopsies. RESULTS: No evidence of Cu insufficiency was associated with dietary Cu restriction. Extrahepatic PSVA survival age exceeded that of I-PSVA (10.3 vs 6.5 years), and complete ligation survival age exceeded that of partial ligation (E-PSVA, 12.5 vs 10.5 years; I-PSVA, 12.0 vs 6.6 years). Survival age of complete and partial ligation exceeded unstratified medically managed dogs (E-PSVA, 9.1 years; I-PSVA, 5.0 years); however, survival age of Cu-restricted medically managed dogs (E-PSVA, 9.7 years; I-PSVA, 6.5 years) did not differ from those that underwent partial ligation. Pathologic liver Cu accumulation occurred in 9 of 30 (30%) biopsies from dogs fed ≥ 0.40 mg of Cu/100 kcal. CONCLUSIONS: Copper restriction of 0.10 to 0.12 mg/100 kcal is nutritionally sufficient for dogs with PSVA. While complete ligation achieves best survival, partial ligation and medical management with Cu-restricted prescription liver diets can achieve substantial longevity. Liver Cu accumulation occurred only with diets with ≥ 0.40 mg of Cu/100 kcal. CLINICAL RELEVANCE: Cu nutritional adequacy, despite intake below regulatory thresholds, warrants reconsideration of current limits. Case-based data provide a survival reference for canine PSVA with different managerial strategies and confirm risk for liver Cu accumulation with a dietary intake of ≥ 0.40 mg of Cu/100 kcal.