The LiMAx test: a new liver function test for predicting postoperative outcome in liver surgery

Abstract

Background: Liver failure has remained a major cause of mortality after hepatectomy, but it is difficult to predict preoperatively. This study describes the introduction into clinical practice of the new LiMAx test and provides an algorithm for its use in the clinical management of hepatic tumours.

Methods: Patients with hepatic tumours and indications for hepatectomy were investigated perioperatively with the LiMAx test. In one patient, analysis of liver volume was carried out with preoperative three-dimensional virtual resection.

Results: A total of 329 patients with hepatic tumours were evaluated for hepatectomy. Blinded preoperative LiMAx values were significantly higher before resection (n= 139; mean 351 microg/kg/h, range 285-451 microg/kg/h) than before refusal (n= 29; mean 299 microg/kg/h, range 223-376 microg/kg/h; P= 0.009). In-hospital mortality rates were 38.1% (8/21 patients), 10.5% (2/19 patients) and 1.0% (1/99 patients) for postoperative LiMAx of <80 microg/kg/h, 80-100 microg/kg/h and >100 microg/kg/h, respectively (P < 0.0001). A decision tree was developed to avoid critical values and its prospective preoperative application revealed a reduction in mortality from 9.4% to 3.4% (P= 0.019).

Discussion: The LiMAx test can validly determine liver function capacity and is feasible in every clinical situation. Combination with virtual resection could enable the calculation of residual liver function. The LiMAx decision tree algorithm for hepatectomy might significantly improve preoperative evaluation and postoperative outcome in liver surgery.

Figure 1

Preoperative LiMAx evaluation. The box plots present LiMAx values determined during preoperative evaluation, divided into resected patients and patients refused surgery. Different results were obtained during (A) the initial clinical studies and (B) the later routine application of the LiMAx test. Boxes indicate medians with interquartile ranges; bars represent minimum and maximum values

Figure 2

Development of liver function after hepatectomy, showing the perioperative course of liver function capacity, as determined by the LiMAx test. The patients were divided into surviving and deceased groups. Median values with error bars represent 75% and 25% quartiles. LiMAx readouts were compared using the Mann–Whitney U-test. Data for the following tests were available: [Table: see text]

Figure 3

The LiMAx algorithm: a clinical decision tree for preoperative evaluation before hepatectomy. LTX, liver transplant; CT, computed tomography

Figure 4

Planning of surgery by volume and function analysis, demonstrated by prospective volume and function analysis in one patient. Preoperative LiMAx was 307 µg/kg/h; functional liver volume was 1450 ml, tumour volume was 153 ml. A right hemi-hepatectomy was planned during virtual resection with a functional resection of 599 ml, thus resulting in a residual liver volume of 698 ml (53.8%) and a residual LiMAx of 165 µg/kg/h. The initial postoperative LiMAx test revealed a liver function capacity of 169 µg/kg/h. (A) The preoperative computed tomography (CT) scan is converted into a 3D construction. The tumour is shown in yellow, the planned liver resection in red. A representative slide and the calculated data for surgery are shown beneath. (B) Confirmation of the planned volume in the postoperative CT scan. A representative slide and the measured postoperative values are shown beneath. Portal vein branches are displayed in blue and hepatic artery branches in red