Page 36 - Read Online

Marasco et al. Hepatoma Res 2020;6:32 I http://dx.doi.org/10.20517/2394-5079.2019.54 Page 5 of 17

Table 2. Studies evaluating ICG in predicting PHLF
Authors Country Population Etiology Outcome Nr. cases Technique ICG cut-off AUROC
Kitano et al. [63] , 1997 Japan 54 N/A Hospital mortality 7 ICG-r15 14% N/A
Lau et al. [58] , 1997 Hong Kong 127 N/A Death 14 ICG-r15 14% (major hep.) N/A
23% (minor hep.)
Lam et al. [57] , 1999 Hong Kong 117 N/A Postoperative N/A ICG-r15 14% N/A
complications
Hsia et al. [64] , 2000 Taiwan 168 Mixed Morbidity 51 ICG-r15 <10% / >20% N/A
Death 3
Lao et al. [65] , 2005 China 255 N/A Decompensation N/A ICG-r15 10-20% N/A
Zou et al. [37] , 2018 China 473 85% HBV PHLF 50 ICG-r15 N/A 0.668
Hwang et al. [66] , 2015 South Korea 723 81% HBV Death from PHLF 6 FRL-kICG <0.05 N/A
Wang et al. , 2018 China 185 83% HBV Severe PHLF 23 ICG-r15 7.1% 0.724
[8]
Kim DK et al. [67] 2018 South 73 Mixed PHLF 18 ICG-PDR N/A 0.748
Korea
Wang et al. [68] , 2019 China 35 Mixed PHLF 16 Intra- 13.8% (day 1) 0.540
Day 1-3-5 operative 13.8% (day 3) 0.800
ICG-r15 22.7% (day 5) 0.910
ICG: Clearance of Indocyanine green; ICG-r15: ICG 15 min retention test; FRL-kICG: ICG constant fraction of future remnant liver; ICG-
PDR: ICG-plasma disappearance rate; hep: hepatectomy; HBV: hepatitis B virus; N/A: not available; PHLF: post-hepatectomy liver failure

Germany), was developed. The device uses a finger optical probe, which detects, after ICG infusion, the
fractional pulsatile changes in optical absorption. The device has already been validated in several studies [50,51]

[50]
with good correlation with ICG-r15results, comparable with correction of a mathematical formula .
[48]
Since ICG clearance depends on blood flow, it was associated with portal hypertension and liver function
for its pharmacokinetics (uptake and excretion through the hepatocytes) as well [47,52-54] . Thus, in Eastern
countries it is considered an accurate method to assess liver functional reserve pre-operatively and has been
[47]
used for almost 30 years ; on the other hand, in Western countries, it is not widely used because it is highly
[47]
influenced by hepatic blood flow and thus, by other conditions that could affect it.
The normal ICG-r15 value is about 10% . The ICG-r15 reported cut-off for performing a safe major
[55]
hepatectomy is between 14% and 17%, the latter in younger patients with milder liver disease [56,57] .
Other authors have reported different cut-offs of 14% and 23% for safe major and minor hepatectomy
[57]
respectively [55,58] . In another previous study with age and sex-matched patients, the authors found no
difference in terms of PHLF and mortality between patients with ICG-r15 of more than, and less than
14% who have undergone major hepatectomy. However, to date, the reported upper limit of ICG-r15 for
[59]
considering liver resection is 40% . The accuracy of ICG-r15 in predicting PHLF could be increased with
[59]
the combination of bilirubin levels and ascites . Several authors comparing the performance of ICG-r15
[60]
with other parameters found that it was superior to MELD and that the combination with platelet count,
[8]
portal hypertension (ICG-r15 cut-off value of 7.1%, sensitivity 52.2% and specificity 89.5%) and Child-
Pugh stage was able to improve its accuracy. Moreover, liver stiffness measurement (LSM) was also found
[61]
[62]
to correlate with ICG-r15 and to provide additional information on the prognosis of the patient . Other
authors have found good correlation when comparing ICG-r15 with the degree of portal hypertension [48,54] .
In conclusion, no definitive lower ICG-r15 cut-offs for distinguishing between safe minor or major
hepatectomy are currently available, as shown in Table 2 [8,37,57,58,63-67] ; major hepatectomy in the presence
of unsatisfactory ICG-r15 results should be performed only in high-volume centers. ICG-r15 could be
considered a good marker of liver function and indirectly, of the degree of portal hypertension. Further
studies are needed however, for this latter association.

Portal hypertension scores
Plated to spleen stiffness ratio PSR
Another widely used biochemical score is the PSR (platelet count-to-spleen ratio), which consists of the
3
[69]
ratio between PLT (expressed in number/mm ) and spleen diameter (mm) . The PSR value is strictly