Development and application of a scoring system for prognostic evaluation of equine liver biopsies

Abstract

Summary Reasons for performing study: The study was designed to investigate the prognostic value of liver biopsy during investigation of cases of suspected liver disease in mature horses. Hypothesis: That liver biopsy is the most prognostically useful technique in common usage in the investigation of suspected liver disease. Methods: This study examined the prognostic value of liver biopsy during the investigation of suspected liver disease in 73 mature horses. Histopathological variables comprising fibrosis, irreversible cytopathology, inflammatory infiltration, haemosiderin accumulation and biliary hyperplasia were found to be significant predictors of nonsurvival and were used to formulate a weighted biopsy score representing a prognostically useful broad comparative index of histopathological severity. Minimum and maximum possible scores were 0 and 14 points, respectively. Results: Retrospective application of the biopsy scoring system to the study population indicated that horses with scores of 0 or 1 were equally likely to survive to 6 months with a combined mortality of 4%. Horses with biopsy scores between 2 and 6 had a combined mortality of 33% and were at a 12‐fold increased risk of nonsurvival within 6 months (hazard ratio = 12.04, 95%CI 1.34–107.81, P = 0.026) compared to horses with a biopsy score of 0. Horses with biopsy scores between 7 and 14 had a combined mortality of 86% and were at a 46‐fold increased risk of nonsurvival (hazard ratio = 46.01, 95%CI 5.92–357.5, P < 0.001) compared to horses with biopsy score 0. Conclusions: Application of the biopsy scoring system to histopathological findings in liver biopsy specimens was very useful in predicting survival of cases of suspected liver disease. Potential relevance: Application of the findings in this study may not be directly applicable to other case populations. However, liver biopsy appears to be the most valuable prognostic technique employed during the investigation of suspected cases of liver disease in mature horses.

Blood parameters in female Zandi lambs as affected by liver biopsy methodology

“…However, the effect of stress on corticosteroids may be another intervening factor for altering serum inorganic phosphate and magnesium levels. Examination of liver biopsies may establish the presence of liver disease, provide a specific diagnosis, guide therapeutic choice, and also help determine prognosis in cases of suspected liver disease (Durham et al 2003;Pearson 2009). The major deficiency of the method lies in the small sample that is obtained, and unless the liver change is diffuse the sample may not be representative (Radostits et al 2007).…”

Overview of Clinical Pathology and the Horse

“…Liver enzymes along with bile acids and biopsies are important for determining prognosis and also disease progression. 70,71 AST and SDH are enzymes that directly reflect hepatocellular disease and leak from these cells, whereas alkaline phosphatase (ALP) and GGT are considered biliary related or cholestatic indicators and are induced by disease processes rather than leakage enzymes ( Table 5). GGT may also elevate with dorsal colon displacement and as a nonspecific finding with induction from medications or supplements; nonspecific increases in GGT tend to be less than 2 times the reference intervals.…”

Hepatic insufficiency

“…The frequent inclusion of iron in proprietary equine micronutrient supplements is of special concern owing to its known capacity for hepatotoxicity in horses (Mullaney & Brown 1988, Edens et al 1993 and the frequent finding of excessive iron in equine liver biopsies (Durham et al 2003b). Selection of ironfree and copper-free products is recommended.…”