What is the limit of graft size for successful living donor liver transplantation in adults?

A Novel Method for the Prevention and Treatment of Small-for-Size Syndrome in Liver Transplantation

BACKGROUND

Currently there is no consensus on the optimal management of small-for-size syndrome following liver transplantation. Here we describe a technique to alleviate portal hypertension and improve the hepatocyte reperfusion in small-for-size liver transplantation in a Lewis rat model.

METHODS

The rats underwent trans-portal vein intra-hepatic portosystemic shunt using a self-developed porous conical tube (TPIPSS: Fig. 1) on small-for-size liver transplants (SFS) with right lobe graft. The treatment effect was evaluated by comparing hemodynamic parameters, morphological changes, serum parameters, ET-1 and eNOS expression, hepatocyte proliferation and apoptosis, CYP3A2 levels, postoperative complications, and survival between the two groups with SFS liver transplants.

RESULTS

Porous conical prosthesis prolonged the filling time of small-for-size grafts. Moreover, grafts with TPIPSS showed a lower portal vein pressure, improved microcirculatory flow, alleviated histological changes, decreased ET-1 and increased eNOS expressions, and significantly less damage to liver function comparing to grafts without TPIPSS. Mean survival and overall 30-day survival were significantly higher in the TPIPSS group.

CONCLUSIONS

These results demonstrate that porous conical tube as trans-portal vein intra-hepatic portosystemic shunt device is an effective way to alleviate portal vein hypertension and improve hepatocyte reperfusion after small-for-size liver transplantation.

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.

Improved preservation and microcirculation with POLYSOL after partial liver transplantation in rats

BACKGROUND

Due to the severe shortage of deceased donors, demand for living-donor liver transplantation (LDLT) has increased worldwide. Here, we compared POLYSOL, a recently developed low-viscosity preservation solution, and histidine-tryptophan-ketoglutarate (HTK) for cold storage of partial liver graft in this study.

METHODS

Partial liver transplantations with 30% of the native liver were performed in Lewis rats. The graft livers were flushed with either HTK or POLYSOL (n = 25, respectively) and stored in the respective solution for 3 h at 5°C. Graft function was evaluated regarding ischemia-reperfusion injury and regeneration at 1, 3, 24, and 168 h after reperfusion.

RESULTS

POLYSOL preservation resulted in improvement of portal venous flow (HTK versus POLYSOL; mean ± SEM: 16.8 ± 2.2 versus 21.6 ± 2.1 mL/min; P = 0.005), microcirculation (383 ± 63 versus 532 ± 64 Flux; P = 0.045), ALT (310.2 ± 56.1 versus 181.8 ± 17.0 IU/L; P = 0.0262), LDH (4052.4 ± 764.4 versus 2494.1 ± 410.0 IU/L; P = 0.0215), total bilirubin (21.6 ± 14.2 versus 4.0 ± 0.6 IU/L; P = 0.0236), malondialdehyde (100.0 ± 4.3 versus 69.2 ± 4.0 nmol/mL; P = 0.0015), as well histologic findings at 24 h. Liver regeneration was improved in POLYSOL with regards to liver weight (4.0 ± 0.2 versus 4.3 ± 0.3 g; P = 0.038) and Ki-67 labeling index (9.67 ± 2.17 versus 1.10 ± 0.14%; P < 0.0001) at 24 h with higher up-regulation of portal VEGF (31.55 ± 5.78 versus 91.94 ± 9.27 pg/mL; P = 0.0052).

CONCLUSIONS

This study showed that POLYSOL improves microcirculation and thus improves the preservation quality of partial liver transplantation.

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.

Liver Graft Volume Estimation in 100 Living Donors: Measure Twice, Cut Once

Estimation of graft volume (GV) is critical in living donor liver transplantation. This study examines the accuracy of formula-derived GV estimates and compares them to both radiogically-derived estimates and actual measurements. We first compared formula-derived estimates of GV and compared them to actual volumes to provide estimates for both right lobe (RL) and left lateral segment (LLS) GV. We then applied these formulae to a validation cohort. Finally, we evaluated both formula-derived and radiologically-derived estimates by comparing them to actual GV measurements. There is a marginal concordance between formula-derived calculation and GV for RL donors, but the error ratio was lower than for radiologic estimates. In contrast, MRI measurements for LLS grafts demonstrated a lower error ratio than formula-derived estimation. Formula-derived estimates of GV should be routinely used in the initial screening of potential living donors as long as their limitations are appreciated.

Living donor liver transplantation with left liver graft

Small-for-size syndrome in LDLT is associated with graft exposure to excessive portal perfusion. Prevention of graft overperfusion in LDLT can be achieved through intraoperative modulation of portal graft inflow. We report a successful LDLT utilising the left lobe with a GV/SLV of only 20%. A 43 year-old patient underwent to LDLT at our institution. During the anhepatic phase a porto-systemic shunt utilizing an interposition vein graft anastomosed between the right portal branch and the right hepatic vein was performed. After graft reperfusion splenectomy was also performed. Portal vein pressure, portal vein flow and hepatic artery flow were recorded. A decrease of portal vein pressure and flow was achieved, and the shunt was left in place. The recipient post-operative course was characterized by good graft function. Small-for-size syndrome by graft overperfusion can be successfully prevented by utilizing inflow modulation of the transplanted graft. This strategy can permit the use of left lobe in adult-to-adult living donor liver transplantation.

Accurate method for clinical assessment of right lobe liver weight in adult living-related liver transplant

INTRODUCTION

Prior to transplantation of segmental liver grafts to adult recipients, it is crucial to confirm that the graft size is safe for the donor, yet adequate for the recipient's metabolic needs. Computed tomography (CT) and magnetic resonance imaging (MRI) are the current best standards. We applied a new formula to estimate right liver lobe weight in living donors and compared our results with CT and MRI.

METHODS

Between August 1998 and December 20, 91 adults received right lobes from living donors. Donor liver volumes were assessed by CT or MRI. Actual weights of right lobe grafts were determined after back table flushing. We estimated whole liver weights using the formula: 772 x body surface area (BSA). Right lobe liver weight was calculated as 57% of the estimated whole liver weight (R-57).

RESULTS

Mean actual right lobe weight (n = 90) was 855.83 +/- 183.4 g. Estimated right lobe weight was 858.08 +/- 90.80 (R-57, P = NS); 1077.35 +/- 263.07 mL for CT (P = .0001), and 1185.07 +/- 350.10 mL for MRI (P = .0001). Mean graft-recipient weight ratio (GRWR) was 1.23%; there was no significant difference with R-57 GRWR but there was a difference from CT and MRI-GRWR (P = .001). The proportion of cases of estimated right lobe weight and GRWR within 20% of the corresponding actual value were 80% and 90%, respectively, for R-57 versus 36% and 43% for the imaging studies (P = .0001).

CONCLUSION

With readily available software to calculate BSA, physicians can predict right lobe weight knowing only the donor's height and weight. CT and MRI will only be necessary for anatomic liver mapping.

Living liver donation: preoperative assessment, anatomic considerations, and long-term outcome

BACKGROUND

A major prerequisite for living donor liver transplantation (LDLT) as an acceptable treatment modality is thoughtful consideration of the donor. However, there has been no comprehensive audit of living liver donation focusing on issues such as donor selection, anatomic surveys, and long-term outcome.

METHODS

Between June 1990 and January 2002 at our institution, 160 LDLTs were performed and 177 patients were referred for LDLT. For these patients, a total of 203 potential donors were screened. The process of donor selection, safety of donor hepatectomy, and postoperative morbidity were investigated. Additionally, an anonymous questionnaire was administered to 100 donors who had undergone LDLT more than 3 years previously.

RESULTS

Thirty-eight (19%) of the 203 donor candidates were excluded. Precise estimation of the hepatic anatomy was indispensable for donor safety. None of the donors showed prolonged postoperative liver dysfunction nor developed complications requiring reoperation or readmission. There was no donor mortality. The responses to the questionnaire indicated that 95% of the living donors had not felt coerced to donate and that 5% were neutral about coercion pressure. There were no severe postoperative aftereffects, but minor problems were reported by 51% of the respondents.

CONCLUSIONS

Our appraisal of the perioperative and long-term postoperative course of LDLT donors revealed that although most donors are satisfied after undergoing LDLT, there is a need for strict attention to the process of donor selection and long-term postoperative follow-up. The outcome of the present series seems to confirm the safety of donor hepatectomy.

Modulation of portal graft inflow: a necessity in adult living-donor liver transplantation?

OBJECTIVE

To evaluate the clinical significance of modulating the recipient portal inflow (rPVF) through perioperative ligation of the splenic artery in adult living-donor liver transplantation (ALDLTx) by focusing on vascular complications, intractable ascites production, and the prevention of small-for-size syndrome (SFSS).

SUMMARY BACKGROUND DATA

In ALDLTx, portal graft flow is enhanced to at least twice the donor value, raising the total liver inflow. Recipient hepatic arterial flow (rHAF) is lower than expected. Portal hyperperfusion of small grafts in larger recipients is thought to be one of the main causes of posttransplant graft dysfunction/SFSS.

METHODS

Seventeen ALDLTx were reviewed for a minimum of 2 months. Patients were divided retrospectively into two groups: G1 (n = 7), without modulation of rPVF, and G2 (n = 10), with splenic artery ligation to decrease rPVF perioperatively. Donor and recipient hepatic hemodynamics were evaluated against graft function and outcome, including correlations between rPVF, graft weight, graft:recipient body weight ratio, and recipient weight.

RESULTS

Following portal and arterial reperfusion, mean rPVF and rPVF/graft weight were much higher than in the donors, whereas mean rHAF and rHAF/graft weight were much lower. No differences were found between groups, except for rPVF and rHAF, which were much more higher and lower, respectively, before splenic artery ligation. In G1 patients, SFSS was seen in two patients and vascular complications occurred in two others. In G2 patients, splenic artery ligation permitted a significant decrease in rPVF, an improvement in rHAF, and the resolution of refractory ascites. Neither SFSS nor vascular complications were seen in G2 patients.

CONCLUSIONS

When a suboptimal graft:recipient body weight ratio is accompanied by high rPVF in ALDLTx, the portal flow should be modulated perioperatively; splenic artery ligation is a simple and safe method that is sufficient to allow this modulation in most patients.

Modulation of portal graft inflow: a necessity in adult living-donor liver transplantation?

OBJECTIVE

To evaluate the clinical significance of modulating the recipient portal inflow (rPVF) through perioperative ligation of the splenic artery in adult living-donor liver transplantation (ALDLTx) by focusing on vascular complications, intractable ascites production, and the prevention of small-for-size syndrome (SFSS).

SUMMARY BACKGROUND DATA

In ALDLTx, portal graft flow is enhanced to at least twice the donor value, raising the total liver inflow. Recipient hepatic arterial flow (rHAF) is lower than expected. Portal hyperperfusion of small grafts in larger recipients is thought to be one of the main causes of posttransplant graft dysfunction/SFSS.

METHODS

Seventeen ALDLTx were reviewed for a minimum of 2 months. Patients were divided retrospectively into two groups: G1 (n = 7), without modulation of rPVF, and G2 (n = 10), with splenic artery ligation to decrease rPVF perioperatively. Donor and recipient hepatic hemodynamics were evaluated against graft function and outcome, including correlations between rPVF, graft weight, graft:recipient body weight ratio, and recipient weight.

RESULTS

Following portal and arterial reperfusion, mean rPVF and rPVF/graft weight were much higher than in the donors, whereas mean rHAF and rHAF/graft weight were much lower. No differences were found between groups, except for rPVF and rHAF, which were much more higher and lower, respectively, before splenic artery ligation. In G1 patients, SFSS was seen in two patients and vascular complications occurred in two others. In G2 patients, splenic artery ligation permitted a significant decrease in rPVF, an improvement in rHAF, and the resolution of refractory ascites. Neither SFSS nor vascular complications were seen in G2 patients.

CONCLUSIONS

When a suboptimal graft:recipient body weight ratio is accompanied by high rPVF in ALDLTx, the portal flow should be modulated perioperatively; splenic artery ligation is a simple and safe method that is sufficient to allow this modulation in most patients.