Outcome of adult living donor liver transplantation using small volume of left liver graft less than 1% of body weight

Hepatic volume profiles in potential living liver donors with anomalous right-sided ligamentum teres

PURPOSE

In living liver donors with rare anatomical anomaly of right-sided ligamentum teres (RSLT), right or left hemiliver procurement is commonly contraindicated. The purpose of this study was to evaluate the hepatic volume profiles in potential donors with RSLT using semi-automated CT volumetry (CTV).

METHODS

Among 5535 potential donor candidates in our institution between April 2003 and May 2019, 23 cases of RSLT (0.4%) were included. Proportional liver volumes were measured using semi-automated CTV and compared with those of manual volumetry and intraoperative graft weights (seven surgical cases).

RESULTS

The mean percentage volume of the right posterior section was significantly larger than that of the left hemiliver (38.5 ± 8.4% vs. 23.3 ± 5.7%, P < 0.001). Particularly in independent right lateral type, the mean percentage volume of the right posterior section was about two times larger to that of the left hemiliver (41.5% ± 6.5% vs. 21.9% ± 4.4%, P < 0.001), whereas the volume proportions of these two parts were similar between the two parts in bifurcation and trifurcation types (P = 0.810 and 0.979, respectively). Semi-automated CTV of corresponding whole liver, right posterior section, right anterior section, and left hemiliver showed strong correlations with manual CTV (r = 0.989-0.998; P < 0.001). For the seven surgical cases, the graft weights estimated by semi-automated CTV showed a significant correlation with intraoperative graft weights (r = 0.972; P < 0.001).

CONCLUSION

In independent right lateral type of RSLT, the right posterior section tends to be significantly larger than left hemiliver, and may be an alternative option for graft in potential living liver donors with this rare anatomical anomaly.

Reproducibility and reliability of computed tomography volumetry in estimation of the right-lobe graft weight in adult-to-adult living donor liver transplantation: Cantlie's line vs portal vein territorialization

BACKGROUND/PURPOSE

In living-donor liver transplantation (LDLT), liver volume assessment is a mandatory step in determining donor appropriateness. This study aimed to compare reliability and reproducibility between two major methods to define virtual hepatectomy plane, based on Cantlie's line (CTV-Cantlie) and portal vein territorialization (CTV-PVT) for right-lobe graft weight estimation in LDLT.

METHODS

A total of 188 donors who underwent preoperative CT scans were included. The liver was divided into right and left lobes using CTV-Cantlie and CTV-PTV measurements by two readers. Intraclass correlation coefficient (ICC) was used to determine interreader variability of hepatic weight measured using each CTV method. Intraoperative graft weight (IOW) was used as reference standard of right-lobe graft weight. Pearson correlation test was performed to determine correlation coefficients between presumed graft weight by each CTV method and IOW.

RESULTS

Intraclass correlation coefficients for total liver weight were roughly equivalent between the two CTV methods (CTV-Cantlie: 0.965 [95% CI, 0.954-0.974], CTV-PVT: 0.977 [0.970-0.983]). However, ICCs of right-and left-lobe weights between two readers were higher with CTV-PVT (0.997 and 0.850) than with CTV-Cantlie (0.829 and 0.668). The IOW was 716.0 ± 162.0 g. Correlation coefficients between presumed graft weight by CTV-Cantlie or CTV-PVT and IOW were 0.722 and 0.807, respectively (both P < .001).

CONCLUSIONS

For estimation of the right-lobe graft weight in LDLT, CTV-PVT may provide higher reliability and reproducibility than CTV-Cantlie.

Estimation of the Right Posterior Section Volume in Live Liver Donors: Semiautomated CT Volumetry Using Portal Vein Segmentation

RATIONALE AND OBJECTIVES

To determine the accuracy of semiautomated CT volumetry using portal vein (PV) segmentation to estimate volume of the right posterior section (RPS) graft compared to intraoperative measured weight (W) in live liver donors.

MATERIALS AND METHODS

Among 23 donors who donated RPS grafts for liver transplantation in our institution from April 2003 to August 2016, 17 donors with CT scans within 3 months of liver procurement and PV anatomy of type I-III were included. RPS volumes were retrospectively evaluated by semiautomated CT volumetry (RPSV_CTV) and by measurement of standard liver volume (SLV) and PV area ratio (RPSV_SLV). RPS volumes were compared to W for correlation coefficients, (absolute) difference, and (absolute) percentage deviation. Linear fitting was performed to identify the method that yielded the greatest correlation with W.

RESULTS

Mean values of RPSV_CTV, RPSV_SLV, and W were 503.4 ± 97.8 mL (346.6-686.0), 516.54 ± 146.20 (274.06-776.32), and 518.8 ± 122.4 (370.0-789.0), respectively. RPSV_CTV was strongly correlated with W (r = 0.9414; p < 0.0001), whereas RPSV_SLV was only moderately did (r = 0.5899; p = 0.0127). RPSV_CTV showed a significantly smaller absolute difference (35.20 ± 30.82 vs. 104.79 ± 60.27, p = 0.004) and absolute percentage deviation (6.61 ± 4.90 vs. 19.92 ± 10.37, p < 0.0001) from W. Equation correlating RPSV_CTV and W was W = -74.7191 + 1.1791 RPSV_CTV (R² = 0.8862; p < 0.001).

CONCLUSION

RPSV_CTV yields smaller absolute difference than RPSV_SLV for estimating intraoperative measured weight of RPS in live liver donors. Semiautomated CT volumetry using PV segmentation is feasible for the estimation of the volume of the RPS of the liver, and RPSV_CTV was strongly correlated with W (r = 0.9414; p < 0.0001).

Hepatic Hemodynamics and Portal Flow Modulation: The A2ALL Experience

OBJECTIVE

A principal aim of the Adult-to-Adult Living Donor Liver Transplantation Cohort Study was to study hepatic blood flow and effect of portal flow modulation on graft outcomes in the setting of increasing use of smaller and left lobe grafts.

METHODS

Recipients of 274 living donor liver transplant were enrolled in the Adult-to-Adult Living Donor Liver Transplantation Cohort Study, including 233 (85.0%) right lobes, 40 (14.6%) left lobes, and 1 (0.5%) left lateral section. Hepatic hemodynamics were recorded after reperfusion. A total of 57 portal flow modulations were performed on 52 subjects.

RESULTS

Modulation lowered portal pressure in 68% of subjects with inconsistent effects on hepatic arterial and portal flow. A higher rate of graft dysfunction was observed in modulated vs. unmodulated subjects (31% vs. 18%; P = 0.03); however, graft survival in modulated subjects was not different from unmodulated subjects at 3 years.

CONCLUSIONS

These results suggest the need for a study using a prespecified portal flow modulation protocol with defined indications to better define the effects of these interventions.

Resection plane-dependent error in computed tomography volumetry of the right hepatic lobe in living liver donors

Background/Aims

Computed tomography (CT) hepatic volumetry is currently accepted as the most reliable method for preoperative estimation of graft weight in living donor liver transplantation (LDLT). However, several factors can cause inaccuracies in CT volumetry compared to real graft weight. The purpose of this study was to determine the frequency and degree of resection plane-dependent error in CT volumetry of the right hepatic lobe in LDLT.

Methods

Forty-six living liver donors underwent CT before donor surgery and on postoperative day 7. Prospective CT volumetry (V_P) was measured via the assumptive hepatectomy plane. Retrospective liver volume (V_R) was measured using the actual plane by comparing preoperative and postoperative CT. Compared with intraoperatively measured weight (W), errors in percentage (%) V_P and V_R were evaluated. Plane-dependent error in V_P was defined as the absolute difference between V_P and V_R. % plane-dependent error was defined as follows: |V_P–V_R|/W∙100.

Results

Mean V_P, V_R, and W were 761.9 mL, 755.0 mL, and 696.9 g. Mean and % errors in V_P were 73.3 mL and 10.7%. Mean error and % error in V_R were 64.4 mL and 9.3%. Mean plane-dependent error in V_P was 32.4 mL. Mean % plane-dependent error was 4.7%. Plane-dependent error in V_P exceeded 10% of W in approximately 10% of the subjects in our study.

Conclusions

There was approximately 5% plane-dependent error in liver V_P on CT volumetry. Plane-dependent error in V_P exceeded 10% of W in approximately 10% of LDLT donors in our study. This error should be considered, especially when CT volumetry is performed by a less experienced operator who is not well acquainted with the donor hepatectomy plane.

Living donor liver transplantation in patients weighing ≥100 kg: Low graft weight and obesity do not impact outcomes

Living donor liver transplantation (LDLT) in obese patients raises concerns with regards to obtaining grafts of "adequate" graft-to-recipient weight ratio (GRWR) and the impact of obesity on the outcomes of LDLT. LDLT outcomes in patients weighing ≥100 kg were compared with those weighing <100 kg. Patients weighing ≥100 kg were divided into 3 categories based on the GRWR of the grafts they received. Groups 1, 2, and 3 included patients with GRWR ≥0.8%, between 0.65% and 0.8%, and <0.65%, respectively. The 56 (6.5%) adult liver transplants were performed in patients weighing 100 kg or more. Except for higher mean body mass index (35.8 versus 25.2 kg/m² ; P value < 0.01) and grafts of lower GRWR in obese patients (0.74% versus 1.02%; P value < 0.01), all other parameters were similar between the 2 groups. Despite obesity and smaller grafts, the posttransplant outcomes such as day to normal bilirubin and international normalized ratio; infective, respiratory, and biliary complications; and hospital mortality were similar between the 2 groups. On comparing obese patients in the 3 GRWR categories, except for graft weight (985 versus 769 versus 646 g; P value < 0.01), all the pretransplant parameters were comparable. There was no significant difference in terms of graft function, postoperative morbidity, and hospital mortality between patients with grafts of normal GRWR and those with grafts of low and very low GRWR. Grafts of low GRWR give satisfactory results in obese patients undergoing LDLT and obesity does not adversely impact the outcome of LDLT. Liver Transplantation 23:35-42 2017 AASLD.

Role of hepatic stellate cells on graft injury after small-for-size liver transplantation

BACKGROUND AND AIM

Small-for-size grafts are prone to mechanical injury and a series of chemical injuries that are related to hemodynamic force. Hepatic stellate cells activate and trans-differentiate into contractile myofibroblast-like cells during liver injury. However, the role of hepatic stellate cells on sinusoidal microcirculation is unknown with small-for-size grafts.

METHODS

Thirty-five percent of small-for-size liver transplantation was performed with rats as donors and recipients. Endothelin-1 levels as well as hepatic stellate cells activation-related protein expression, endothelin-1 receptors, and ultrastructural changes were examined. The cellular localizations of two types of endothelin-1 receptors were detected. Furthermore, liver function and sinusoidal microcirculation were analyzed using two different selective antagonists of endothelin-1 receptor.

RESULTS

Intragraft expression of hepatic stellate cells activation-related protein such as desmin, crystallin-B and smooth muscle α-actin was upregulated as well as serum endothelin-1 levels and intragraft expression of the two endothelin receptors. The antagonist to endothelin-1 A receptor not to the endothelin-1 B receptor could attenuate microcirculatory disturbance and improve liver function.

CONCLUSIONS

Small-for-size liver transplantation displayed increased hepatic stellate cells activation and high level of endothelin-1 binding to upregulation of endothelin-1 A receptor on hepatic stellate cells, which contracted hepatic sinusoid inducing graft injury manifested as reduction of sinusoidal perfusion rate and elevation of sinusoidal blood flow.

Right lobe estimated blood-free weight for living donor liver transplantation: accuracy of automated blood-free CT volumetry--preliminary results

PURPOSE

To determine the relative accuracy of automated blood-free to blood-filled computed tomographic (CT) volumetry for estimation of right-lobe weight in living donor liver transplantation.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board; informed consent was waived. Between October 1, 2008, and April 30, 2009, 88 live liver donors (54 men, 34 women; mean age, 26.1 years +/- 6.9 [standard deviation]) who underwent CT and had their right lobes procured in the study institution were included. Automated measurement of blood-filled volume (V(BFill)) and blood-free volume (V(BFree)) of the right lobe was performed by using 16-row multidetector CT performed with 5-mm intervals. Actual hepatic weight was measured blood free during surgery. Percentage blood volume, %V(B), was calculated as follows: %V(B) = V(BFill) - V(BFree)/V(BFill) . 100. Pearson tests were performed to determine correlation coefficients between V(BFill)/1.22 or V(BFree) and weight. Percentage deviation and percentage absolute deviation of V(BFree) from weight were compared with those of V(BFill)/1.22 by using a paired t test or Wilcoxon rank sum test. Regression analysis was performed between V(BFree) and weight.

RESULTS

Mean V(BFill), V(BFree), and weight were 789.0 mL +/- 126.4, 713.9 mL +/- 114.4, and 717.8 g +/- 110.4. Percentage blood volume varied from 6.5% to 19.8% (mean, 9.5%). Compared with weight, the correlation coefficient was slightly higher with V(BFree) (r = 0.9140) than with V(BFill)/1.22 (r = 0.8909). Mean percentage deviation and percentage absolute deviation were significantly smaller with V(BFree) (-0.4% +/- 6.3, 5.0% +/- 3.8; P < .001) than with V(BFill)/1.22 (-9.8% +/- 6.5, 10.2% +/- 7.3; P < .001). The equation relating V(BFree) and weight, W, was as follows: W = (0.8815 . V(BFree)) + 88.5117, with R(2) of 0.8355 (P < .001).

CONCLUSION

At automated CT volumetry in live liver donors, the percentage blood volume varies. The V(BFree) is more accurate than is V(BFill)/1.22 in estimation of hepatic weight.

A graft to body weight ratio less than 0.8 does not exclude adult-to-adult right-lobe living donor liver transplantation

Many centers require a minimal graft to body weight ratio (GBWR) >or= 0.8 as an arbitrary threshold to proceed with right-lobe living donor liver transplantation (RL-LDLT), and there is often hesitancy about transplanting lower volume living donor (LD) liver grafts into sicker patients. The data supporting this dogma, based on the early experience with RL-LDLT at Asian centers, are weak. To determine the effect of LD liver volume in the modern era, we investigated the impact of GBWR on the outcome of RL-LDLT with a GBWR as low as 0.6 at the University of Toronto. Between April 2000 and September 2008, 271 adult-to-adult RL-LDLT procedures and 614 deceased donor liver transplants were performed. Twenty-two living donor liver transplantation (LDLT) cases with a GBWR of 0.59 to 0.79 (group A) were compared with 249 LDLT cases with a GBWR >or= 0.8 (group B) and with 66 full-graft deceased donor liver transplants (group C), who were matched 3:1 according to donor and recipient age, Model for End-Stage Liver Disease score, and presence of hepatitis C and hepatocellular carcinoma with the low-GBWR group. Portal vein shunts were not used. Markers of reperfusion injury [aspartate aminotransferase (AST) and alanine aminotransferase (ALT)], graft function (international normalized ratio and bilirubin), complications graded by the Clavien score, and graft and patient survival were compared. As expected, LD recipients had a significantly shorter cold ischemia time (94 +/- 43 minutes for A, 96 +/- 57 minutes for B, and 453 +/- 152 minutes for C, P = 0.0001). However, the peak AST, peak ALT, absolute decrease in the international normalized ratio, day 7 bilirubin level, postoperative creatinine clearance, complication rate graded by the Clavien score, and median hospital stay were similar in all groups. The rate of biliary complications was higher with LD grafts than deceased donor grafts (19% for A versus 10% for B and 0% for C, P = 0.2). Patient survival was similar in all groups at 1, 3, and 5 years (91% for A versus 89% for B and 93% for C at 1 year, 87% for A versus 81% for B and 89% for C at 3 years, and 83% for A versus 81% for B and 87% for C at 5 years, P = 0.63). A Cox proportional regression analysis revealed only hepatitis C virus as a risk factor for poorer graft survival and not GBWR as a continuous or categorical variable. In conclusion, we found no evidence of inferior outcomes with smaller size grafts versus larger size LD grafts or full-size deceased donor grafts. Further studies are warranted to examine the factors affecting the function of smaller grafts for living liver donation and thereby define the safe lower limits for transplantation.

Living Donor Right Liver Lobes: Preoperative CT Volumetric Measurement for Calculation of Intraoperative Weight and Volume

PURPOSE

To prospectively develop equations for the calculation of expected intraoperative weight and volume of a living donor's right liver lobe by using preoperative computed tomography (CT) for volumetric measurement.

MATERIALS AND METHODS

After medical ethics committee and state medical board approval, informed consent was obtained from eight female and eight male living donors (age range, 18-63 years) for participation in preoperative CT volumetric measurement of the right liver lobes by using the summation-of-area method. Intraoperatively, the graft was weighed, and the volume of the graft was determined by means of water displacement. Distributions of pre- and intraoperative data were depicted as Tukey box-and-whisker diagrams. Then, linear regressions were calculated, and the results were depicted as scatterplots. On the basis of intraoperative data, physical density of the parenchyma was calculated by dividing weight by volume of the graft.

RESULTS

Preoperative measurement of grafts resulted in a mean volume of 929 mL +/- 176 (standard deviation); intraoperative mean weight and volume of the grafts were 774 g +/- 138 and 697 mL +/- 139, respectively. All corresponding pre- and intraoperative data correlated significantly (P < .001) with each other. Intraoperatively expected volume (V(intraop)) in millilliters and weight (W(intraop)) in grams can be calculated with the equations V(intra)(op) = (0.656 . V(preop)) + 87.629 mL and W(intra)(op) = (0.678 g/mL . V(preop)) + 143.704 g, respectively, where preoperative volume is V(preop) in milliliters. Physical density of transplanted liver lobes was 1.1172 g/mL +/- 0.1015.

CONCLUSION

By using two equations developed from the data obtained in this study, expected intraoperative weight and volume can properly be determined from CT volumetric measurements.