Liver function following extended hepatectomy can be accurately predicted using remnant liver volume to body weight ratio.

Background: Standardised measurement of remnant liver volume (RLV), where total liver volume (TLV) is calculated from patients' body surface area (RLV-sTLV), has been advocated. Extrapolating the model of living donor liver transplantation, we showed in a pilot study that the simplified RLV/body weight ratio (RLVBWR) was accurate in assessing the functional limit of hepatectomy. The aim of the study was to compare in a prospective series of extended right hepatectomy the predictive value of the RLVBWR and the RLV-sTLV at a cut-off of 0.5% (RLVBWR0.5%) and 20% (RLV-sTLV20%), respectively.

Methods: We studied the impact of RLVBWR0.5% and of RLV-sTLV20% on three months morbidity and mortality in 74 non-cirrhotic patients operated on for malignant tumours. Of these, 47 patients who were not included in the initial pilot study were enrolled in a prospective validation cohort to reappraise the predictive value of each method.

Results: RLVBWR and RLV-sTLV were highly correlated (Pearson correlation coefficient, 0.966). Three months overall and severe morbidity (grade 3b-5) and mortality were significantly increased in groups RLVBWR ≤ 0.5% and RLV-sTLVs ≤ 20% compared to groups >0.5% and >20%, respectively. The sensitivity and specificity in predicting death from liver failure were 100 and 84.1% for RLVBWR0.5% and 60 and 94.2% for RLV-sTLV20%, respectively. Similar results were observed in the validation cohort for the RLVBWR0.5% (lack of statistical power for RLV-sTLV as only 2 patients showed a RLV-sTLV ≤ 20%).

Conclusions: The RLVBWR0.5% is a method of assessing the remnant liver that is simple and as reliable as the standardised RLV-sTLV20%.