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

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.