There have been many attempts to define predictive models for the identification of patients at risk of liver failure after surgery (posthepatectomy liver failure (PHLF)) and death. These have previously been hindered by the lack of a robust definition of PHLF and the two most commonly used definitions – the 50-50 and International Study Group of Liver Surgery (ISGLS) criteria – have now helped with this. These definitions are based on a measure of blood clotting (prothrombin time) and the serum bilirubin concentration, reflecting the synthetic and excretory/detoxifying functions of the liver. One criticism of these is that the criteria are taken on day 5 after surgery, a time-point some have argued is too late to intervene upon.
In a new analysis, Herbert and colleagues present an analysis of 1528 major liver resection patients and examine the changes in serum phosphate levels and creatinine immediate after surgery. It was previously shown a failure of phosphate levels to fall after surgery is associated with liver failure and death (Squires, HPB, 2014). Low serum phosphate after liver resection is well recognised and originally thought to be a consequence of consumption during liver growth (hypertrophy). However, while active take-up of phosphate into the liver after surgery does happen, this is insufficient to fully explain low phosphate levels. The authors point to studies demonstrating a significant increase in the urinary excretion of phosphate following hepatectomy which may also contribute.
Herbert provides a practical definition: creatinine on day 1 post surgery (PoD1) > day of surgery (DoS) and phosphate fails to decrease by 20% from DoS to PoD1. There is a strong association in multivariable analyses with death (Odds ratio 2.53, 1.36–4.71) and PHLF (3.89, 1.85–8.37).
The serum phosphate/creatinine definition identified 52% of those that died, but also 25% that survived without evidence of PHLF. It may be that this can be improved by incorporating other parameters, or my identifying a high risk group a priori. Given the lack of specific therapies beyond that of high quality intensive care, whether death can actually be averted is separate question.