Ad Integrum Functional and Volumetric Recovery in Right Lobe Living Donors: Is It Really Complete 1 Year After Donor Hepatectomy?

Pre-operative assessment of living liver donors' liver anatomy and volumes

Decades of experience supports LDLT as a favorable strategy to reduce waitlist mortality. The multiple regenerative pathways of hepatocytes and other hepatic cells justify the rationale behind it. Nonetheless, living liver donation is still underused and its broader implementation is challenging, mostly due to variability in practices leading to concerns related to donor safety. A non-systematic literature search was conducted for peer-reviewed original articles related to pre-operative evaluation of living liver donor candidates. Eligible studies were synthesized upon consensus for discussion in this up-to-date review. Review of the literature demonstrate that the importance of preoperative assessment of vascular, biliary and liver volume to ensure donor safety and adequate surgical planning for graft procurement is widely recognized. Moreover, data indicates that anatomic variants in vascular and biliary systems in healthy donors are common, present in up to 50% of the population. Therefore, comprehensive mapping and visualizations of each component is needed. Different imaging modalities are reported across practices and are discussed in detail. Lastly, assessment of liver volume must take into account several technical and donor factors that increase the chances of errors in volume estimation, which occurs in up to 10% of the cases. Experience suggests that maximizing donor safety and lessening their risks is a result of integrated experience between hepatobiliary and transplant surgery, along with multidisciplinary efforts in performing a comprehensive pre-operative donor assessment. Although technical advances have increased the accuracy of volume estimation, over- or under-estimation remains a challenge that needs further attention.

Preoperative Alanine Aminotransferase and Remnant Liver Volume Predict Liver Regeneration After Live Donor Hepatectomy

BACKGROUND

Regeneration of the remnant liver in early postoperative period determines the outcome in live liver donors (LLDs). The aim of the current study is to evaluate the factors that influence liver regeneration following live donor hepatectomy.

METHODS

Total liver volume (TLV), estimated graft volume (EGV), and remnant liver volume (RLV) were calculated preoperatively in a prospective study of 154 LLDs. Absolute and percentage growth of remnant liver (regeneration index) in donor was estimated at 7th postoperative day (POD) by computed tomography (CT) volumetric analysis.

RESULTS

One hundred eighteen donors underwent right hepatectomy (RH), 29 underwent left hepatectomy (LH), 6 donors had left lateral sectionectomy (LLS), and one had right posterior sectionectomy. The median percentage growth of remnant liver at the end of the first week was 46.14% (51.74%, 35.32%, and 17.38% for RH, LH, and LLS, respectively). On univariate analysis, female donors (p = 0.051), RH graft (p = 0.001), no steatosis on ultrasonography (p = 0.042), lower TLV (p = 0.029), RLV (p = < 0.001), RLV-to-body weight ratio (RLVBWR) (p = < 0.001), preoperative alanine aminotransferase (ALT) level (p = 0.017), aspartate aminotransferase (AST) (p = 0.035) and higher POD 7 alkaline phosphatase (ALP) (p = 0.033), and POD 7 gamma-glutamyl transferase GGT (p = 0.006) were found to be predictors of greater liver regeneration. Among them, lower RLV (P = 0.008), RLVBWR (p = 0.011), and preoperative ALT level (p = 0.021) were most significant factors predictive of liver regeneration on logistic regression analysis with backward elimination.

CONCLUSION

The liver regenerates rapidly in LLDs following hepatectomy. Low RLV, RLVBWR, and preoperative ALT levels were predictors of liver regeneration in the first week following donor hepatectomy.

Clinical Outcome of Residual Liver Volume and Hepatic Steatosis After Right-Lobe Living-Donor Hepatectomy

Background

We examine how residual liver volume (RLV) and hepatic steatosis (HS) of living liver donors affect the regeneration process and clinical outcomes.

Material/Methods

We longitudinally studied 58 donors who underwent right-lobe hepatectomy during the period February 2014 to February 2015 at a single medical institution. The patients were classified based on RLV (30–35%, 35–40%, 40–50%) subgroups and HS (<10%, 10–30%, 30–50%) subgroups. Clinical parameters such as clinical outcome, liver volumetric recovery (LVR,%) rate and remnant left-liver (RLL,%) growth rate were collected for analysis.

Results

The clinical features of postoperative peak total bilirubin (p=.024) were significant in the 3 RLV subgroups. Body mass index (p=.017), preoperative alanine transaminase (p<.001), and pleural effusion (p=.038) were significant in the 3 HS subgroups. The LVR rate and RLL growth rate equations showed significant variation in regeneration among the 3 RLV subgroups. The LVR rate and RLL growth rate equations did not show significant variation in regeneration among the 3 HS subgroups.

Conclusions

Hyperbilirubinemia was a risk factor in the small-RLV group, and a large amount of pleural effusion was a risk factor in the steatosis 30–50% group. Hepatic steatosis subgroups did not show significantly different degrees of regeneration. The safety of living donors was a major concern while we compiled the extended living-donor criteria presented in this paper.

Impact of donor age on liver regeneration and function following adult living donor liver transplantation

The aim of the present study was to evaluate the impact of donor age on liver function and regeneration following living donor liver transplantation. Donors were divided into an elderly donor group (age >50 years old; n=8) and a young donor group (age <30 years old; n=35). The recipients were also divided into an elderly group (age >50 years old; n=5) and a young group (age <30 years old; n=25). Alanine aminotransferase, aspartate aminotransferase, total bilirubin (TB) and prothrombin time were recorded 1-5 days postoperatively. The liver regeneration ratio (LRR) was recorded 7 and 15 days postoperatively in donors and at 0.5, 1, 3 and 6 months postoperatively in recipients by contrast-enhanced multi-slice spiral computed tomography. Notably, the LRR in the young donor group was significantly increased compared with that in the elderly donor group at 7 days postoperatively (P<0.05). Among recipients, TB in the elderly group was significantly increased compared with that in the young group at 1-5 days postoperatively (P<0.05). The residual liver regeneration rate was decreased and the time of jaundice was prolonged in recipients in the elderly group 7 days postoperatively, but donor age had little impact on the short-term outcome of the residual liver and graft.

Portal venous velocity affects liver regeneration after right lobe living donor hepatectomy

OBJECTIVES

We investigated whether chronological changes in portal flow and clinical factors play a role in the liver regeneration (LR) process after right donor-hepatectomy.

MATERIALS AND METHODS

Participants in this prospective study comprised 58 donors who underwent right donor-hepatectomy during the period February 2014 to February 2015 at a single medical institution. LR was estimated using two equations: remnant left liver (RLL) growth (%) and liver volumetric recovery (LVR) (%). Donors were classified into an excellent regeneration (ER) group or a moderate regeneration (MR) group based on how their LR on postoperative day 7 compared to the median value.

RESULTS

Multivariate analysis revealed that low residual liver volume (OR = .569, 95% CI: .367- .882) and high portal venous velocity in the immediate postoperative period (OR = 1.220, 95% CI: 1.001-1.488) were significant predictors of LR using the RLL growth equation; high portal venous velocity in the immediate postoperative period (OR = 1.325, 95% CI: 1.081-1.622) was a significant predictor of LR using the LVR equation. Based on the two equations, long-term LR was significantly greater in the ER group than in the MR group (p < .001).

CONCLUSION

Portal venous velocity in the immediate postoperative period was an important factor in LR. The critical time for short-term LR is postoperative day 7; it is associated with long-term LR in donor-hepatectomy.

Predictive Factors of Liver Dysfunction After Right Hemihepatectomy for Adult Living Donor Liver Transplantation

BACKGROUND

Living liver donors represent a special group of patients. They are healthy individuals who are exposed to a major surgery, in which the dominant liver proportion is extracted as a graft. Of all potential donor-related morbidities, posthepatectomy liver dysfunction (PHLD) is the most significant as it may be directly related to donor mortality. We aimed to review our data of adult living donor liver transplantation (LDLT) utilizing the right hemiliver grafts to determine the incidence and potential predictors for the development of PHLD, defined according to the International Study Group of Liver Surgery.

METHODS

We reviewed the data of all adult living donors who underwent right hemihepatectomy during the period between May 2004 and 2016.

RESULTS

During the study period, 434 cases underwent right hemihepatectomy for adult LDLT. We divided our cases into 2 groups according to the occurrence of PHLD. A significant lower residual liver volume and percentage were noted in PHLD group. Longer intensive care unit stay and hospital stay, and more postoperative morbidities, were observed in PHLD group. PHLD occurred in 50 cases (11.5%), and most of them were grade A (47 cases [10.8%]). Two cases (0.5%) had grade B requiring diuretic therapy, and 1 case (0.2%) had grade C requiring ultrasound guided tube drainage and surgical exploration finally.

CONCLUSIONS

We should not underestimate the risks of liver donation surgery, especially when utilizing the right hemiliver graft. Donor safety should be ensured by accurate preoperative volumetric assessment of the remnant liver and remnant liver volume limitations must be strictly followed.

Kinetics of liver regeneration in donors after living donor liver transplantation: A retrospective analysis of "2/3rd partial hepatectomy" model at 3 months

BACKGROUND/AIM

Right lobe living donor (2/3rd partial hepatectomy) model is the best way to accurately study liver regeneration process in human beings. We aimed to study the kinetics of liver regeneration after 2/3rd partial hepatectomy in donors.

METHODS

Retrospective analysis of prospectively maintained volumetric recovery data in donors was performed in 23 donors, who underwent 29 contrast-enhanced computed tomography within 3 months for various clinical indications.

RESULTS

The absolute volumetric growth percentages were as follows: 37.60 ± 21.74 at 1st week, 92 ± 53.27 at 2nd week, 115.55 ± 59.65 at 4th week, and 110.79 ± 64.47 at 3 months. On sub-group analysis of our cohort, we found that 4.3%, 17%, 30.4%, and 39% donors attended ≥ 90% volumetric recovery at 1st, 2nd, 4th week, and 3 months, respectively. One patient at 4th week revealed 128% volumetric recovery. There was one more patient who exceeded original total liver volumes (TLV) (111% of TLV) at 2.5 months. The serum bilirubin and INR values peaked at postoperative day (POD) 3rd and then started showing a downward trend from POD 5th onwards.

CONCLUSION

Our study is the first to document complete volumetric recovery in donors as early as 3 weeks. Two of the donors overshot their original TLV during the early regenerative phase.