Donor Remnant Liver Research Articles

Donor safety of remnant liver volumes of less than 30% in living donor liver transplantation: A systematic review and meta-analysis.

This meta-analysis aimed to investigate the acceptability of donor remnant liver volume (RLV) to total liver volume (TLV) ratio (RLV/TLV) being <30% as safe in living donor liver transplantations (LDLTs). Online databases were searched from January 2000 to June 2022. Pooled odds ratios (ORs) and standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated using fixed- or random-effects model. One prospective and seven retrospective studies comprising 1935 patients (164 RLV/TLV <30% vs. 1771 RLV/TLV ≥30%) were included. Overall (OR=1.82; 95% CI [1.24, 2.67]; p=.002) and minor (OR=1.88; 95% CI [1.23, 2.88]; p=.004) morbidities were significantly lower in the RLV/TLV ≥30% group than in the RLV/TLV <30% group (OR=1.82; 95% CI [1.24, 2.67]; p=.002). No significant differences were noted in the major morbidity, biliary complications, and hepatic dysfunction. Peak levels of bilirubin (SMD=.50; 95% CI [.07, .93]; p=.02) and international normalized ratio (SMD=.68; 95% CI [.04, 1.32]; p=.04) were significantly lower in the RLV/TLV≥30% group than in the RLV/TLV <30% group. No significant differences were noted in the peak alanine transferase and aspartate transaminase levels and hospital stay. Considering the safety of the donor as the top priority, the eligibility of a potential liver donor in LDLT whose RLV/TLV is expected to be <30% should not be accepted.

312.9: Mathematical Modelling to Determine Segment Perfusion Parameters for Living Donor Liver Transplantation

Introduction: Adult-to-Adult Living Donor Liver Transplantation (A2ALL-1) Cohort Study focused on hepatic blood flow and effect of portal modulation in smaller and left lobe grafts demonstrating a significantly (p = 0.03) higher graft dysfunction in modulated recipients versus unmodulated. The study concluded the need for prespecified portal flow and hepatic venous outflow modulation protocols to better define outcomes of volumetric interventions. We developed a mathematical model of the liver to determine hemodynamic parameters across segments following simulated liver resections and middle hepatic vein interventions in both the remnant donor liver and recipient grafts to predict functional graft outcomes prior to reperfusion. Methods: Arterial/portal/hepatic vein and terminal portal triad diameters from 12 deceased donor livers and biopsies were used in a custom lumped parameter model developed in MATLAB {Fig(a)}. Blood flow is modeled using the Hagen-Poiseuille equation, and the continuity equation is solved to obtain volume flow rate of the whole liver at every point throughout the network {Fig(b)}. Simulated right hepatectomy in the plane of resection shown in Fig(a) is used to derive variations in blood flow and volume through the modeled left liver lobe {Fig(c)}.Results: Schematic illustrations of the modeling components of liver segments demonstrate volume flow rate encoded in pseudocolor mapping in the donor liver before and after right hepatectomy {Fig(b&c)}. Localized increase in blood flow through 2nd and 3rd generations of vessel division is especially apparent in the donor’s simulated remnant left lobe {Fig(c)}. Volume and flow rate alterations in hepatic venous outflow following ligation/reconstruction of middle hepatic veins in the remnant left lobe is evident. Perfusion parameters in the donor graft are also captured to simulate graft perfusion prior to reperfusion in the recipient. Conclusion: Surgical intervention on the middle hepatic vein (MHV) is critical for donor remnant liver outflow and optimal perfusion in the donor graft. Mathematical simulations to predict hemodynamic inflow – outflow parameters in living donor liver transplantation could help guide MHV ligation and reconstruction as well as predict graft perfusion parameters prior to reperfusion.

The Efficacy of Acoustic Radiation Force Impulse Elastography for Predicting Clinical Outcomes in Living Donor Liver Transplant

Acoustic radiation force impulse (ARFI) elastography is widely used for evaluating liver fibrosis. Here we evaluated the efficacy of ARFI elastography for estimating graft quality and clinical outcomes in living donor liver transplant (LDLT). We retrospectively evaluated the cases of 87 LDLT donors who preoperatively underwent ARFI elastography at Nagasaki University Hospital between August 2010 and June 2016. We analyzed whether the velocity of shear wave (Vs) obtained by ARFI elastography affected the regeneration rate of each donor's remnant liver and the 1-year survival rate of the recipients. There were no significant correlations between Vs value and the donors' age. Only 1 donor (1.1%) showed significant fibrosis, F2(portal fibrosis with few septa) in zero-biopsy. The 7 donors (8.0%), including 1 case, showed a high Vs value (>1.33) that was equal to F2, although there was no abnormal pathologic finding except in 1 case. In those cases, the regeneration rate of the remnant liver after hepatectomy was significantly lower compared to other cases. The 1-year survival rate of the recipients paired with the high-Vs donors was also significantly poorer than that of the other cases (high-Vs: 57.1%, others: 84.2%, P=.04). ARFI elastography might be an effective examination for the preoperative evaluation of the graft quality in LDLT.

Magnetic resonance imaging-derived proton density fat fraction (MRI-PDFF) is a viable alternative to liver biopsy for steatosis quantification in living liver donor transplantation.

This study aimed to investigate whether magnetic resonance imaging-derived proton density fat fraction (MRI-PDFF) can be a viable noninvasive alternative to liver biopsy for the quantification of living liver donor steatosis. Hepatic steatosis for 143 donors was graded by MRI-PDFF. Study endpoints included liver volume regeneration in donors, recipient outcomes including length of hospital stay, deaths, primary non-function (PNF), early allograft dysfunction (EAD), and small for size syndrome (SFSS). Correlation between MRI-PDFF determined donor steatosis and endpoints were analyzed. Donors had lower steatosis grade than non-donors. Donor remnant liver regenerated to an average of 82% of pre-donation volume by 101±24days with no complications. There was no correlation between percent liver regeneration and steatosis severity. Among recipients, 4 underwent redo-transplantation and 6 died, with no association with degree of steatosis. 52 recipients (36%) fulfilled criteria for EAD (driven by INR), with no difference in hepatic steatosis between groups. MRI-PDFF reliably predicted donor outcomes. Living donors with no or mild steatosis based on MRI-PDFF (ie, <20%) and meeting other criteria for donation can expect favorable post-surgical outcomes, including liver regeneration. Recipients had a low rate of death or retransplantation with no association between mild hepatic steatosis and EAD.

Liver volume regeneration after living donor liver transplantation (LD/LDLTx) depends on segmental perfusion

Background: The ability for liver volume regeneration after LD/LDLTx depends on liver morphology, function, perfusion and ischemia reperfusion injury. Methods: Donor and recipient, each n=42. Preoperative CT-volumetry in donors. Preoperative liverfunction test (LiMAx) for donor and recipient. LD: right hemihepatectomy (right-lobe graft, RLG). During LDLTx 3 liver biopsies were taken: 0-biopsy, from RL while ischemia and after reperfusion and stained with HMGB1. After LD and LDLTx on 2.POD LiMAx, on 10.POD and after 6 month (6M) CT-Volumetry and LiMAx were performed. Results: HMGB1-translocation, ischemia time and liver morphology were nearly same in all donors. Liver function in donors is restored on 10. POD (n=14), in recipients on 2. POD (n=14) and increased with 6M (n=10). Donor remnant liver gained after 6M to approx. 85% of total liver volume (n=12) an the RLG in recipients (adjusted to standard liver volume, SLV) gained to approx. 100% of SLV. Segmental volume regeneration (SVR) in RLG is mainly related to portal vein segments P7 and P8 and less P5. Regarding venous segments only perfusion region of right hepatic vein is gaining in contrast to more outflow obstructed perfusion areas of middle hepatic and inferior hepatic vein. In donors portal SVR takes place in P2 and P3, venous SVR occurs only via left hepatic vein. Conclusion: Liver volume regeneration maybe optimized by reduction of outflow obstruction respectively necessary hepatic vein reconstruction.

Adult living donor liver imaging.

Adult living donor liver transplantation (LDLT) is increasingly used for the treatment of end-stage liver disease. The three most commonly harvested grafts for LDLT are left lateral segment, left lobe, and right lobe grafts. The left lateral segment graft, which includes Couinaud's segments II and III, is usually used for pediatric recipients or small size recipients. Most of the adult recipients need either a left or a right lobe graft. Whether a left or right lobe graft should be harvested from the donors depends on estimated graft and donor remnant liver volume, as well as biliary and vascular anatomy. Detailed preoperative assessment of the potential donor liver volumetrics, biliary and vascular anatomy, and liver parenchyma is vital to minimize risks to the donors and maximize benefits to the recipients. Computed tomography (CT) and magnetic resonance imaging (MRI) are currently the imaging modalities of choice in the preoperative evaluation of potential donors. This review provides an overview of key surgical considerations in LDLT that the radiologists must be aware of, and imaging findings on CT and MRI that the radiologists must convey to the surgeons when evaluating potential donors for LDLT.

Middle hepatic vein allocation in adult right lobe living donor liver transplantation.

When adult-to-adult living donor liver transplantation (LDLT) using the right lobe is carried out, there is disagreement between different centers as to whether the middle hepatic vein (MHV) is included or retained by the donor. Ninety-two cases of adult-to-adult LDLT were performed between January 2007 and December 2010 using a right lobe graft. A protocol for MHV allocation was applied according to the donor's remnant liver volume, overall graft/recipient weight ratio (GRWR), and anatomic characteristics of the hepatic vein. Among these cases, there were 44 cases with MHV and 48 cases without MHV. No blood products were used during donor operations, and there was no occurrence of death or small-for-size syndrome after operations. There were statistical differences between Groups I and II according to the ages of the recipients, the actual GRWR, the weights of grafts, the cold storage time of grafts, etc. All patients recovered smoothly; one-, three-, and five-yr survival rates of patients were 96.7%, 92.4%, and 92.4% and of grafts were 95.7%, 91.3%, and 91.3%, respectively. With a reasonable allocation protocol and precise evaluation, either MHV harvested or MHV retained to the donor during adult-to-adult LDLT using the right lobe can achieve good outcome.

Biliary complications including single-donor mortality: experience of 207 adult-to-adult living donor liver transplantations with right liver grafts

BackgroundAfter right lobe donation, biliary complication is the main cause of morbidity. Mortality after right lobe donation has been estimated to be less than 0.5%. Patients and methodsBetween November 2001 and December 2008, 207 adult-to-adult living donor liver transplantations (ALDLT) were undertaken using right lobe grafts. Donors included 173 men and 34 women with a mean age of 28.4 ± 5.2 years. ResultsSiblings comprised 144 (69.6%) cases whereas unrelated donors comprised 63 (30.4%) with a mean body mass index (BMI) of 25.2 ± 2.4. Single and multiple right hepatic ducts (RHD) were present in 82 (39.6%) and 125 (60.3%) donors, respectively. Mean operative time was 360 ± 50min with an estimated blood loss of 950 ± 450ml and returned cell-saver amount of 450 ± 334ml. Mean donor remnant liver volume was 33.5 ± 3.2%. Mean intensive care unit (ICU) stay was 3 ± 0.7 days and mean hospital stay was 14 ± 3.5 days. Modified Clavien classifications were used to stratify all donor biliary complications The overall biliary complications occurred in 27 cases (13.0%). After modified Clavien classification, biliary complications were graded as grade I (n= 10), grade II (n= 2), grade III (n= 14) and grade V (n= 1). Grade I and II (n= 12) biliary complications were successfully managed conservatively. Grade III cases were treated using ultrasound-guided aspiration (USGA), endoscopic retrograde cholangiography (ERCP) and surgery in 10, 2 and 2 donors, respectively. Single donor mortality (Grade V) (0.4%) occurred after uncontrolled biliary leakage with peritonitis that necessitated exploration followed by ERCP with stent insertion but the donor died on day 43 as a result of ongoing sepsis. ConclusionAlthough the majority of biliary complications are minor and can be managed conservatively, uncontrolled biliary leakage is a serious morbidity that should be avoided as it could lead to mortality.

Formation of Venous Collaterals and Regeneration in the Donor Remnant Liver: Volumetric Analysis and Three-Dimensional Visualization

We sought was to quantify and visualize the regeneration of the remnant liver after living donor liver transplantation using computed tomographic (CT) data. For the evaluation of preoperative and follow-up data, we developed a software assistant that was able to compute the volume growth of the remnant liver and liver territories as well as visualize the individual growth of hepatic vessels over time. The software was applied to CT data of 20 donors who underwent right hepatectomy including the middle hepatic vein with at least 3 follow-up examinations in the first year after transplantation. After donation of a right lobe graft, the remnant liver regenerated by an average 77% of the original volume within the first 3 postoperative months and to 86% within the first year. The growth of the left lateral segments was increased compared with that of segment IV in all cases. The visualization showed the growth of the portal vein and the hepatic veins. With the simultaneous display of pre- and postoperative results, it was possible to detect the formation of collaterals between truncated segment IVb veins and the veins of segment IVa or of the left lateral lobe. The software-assisted analysis of follow-up data yielded additional insight into territorial liver regeneration after living donor liver transplantation and allowed for reliable detection of relevant hepatic vein collaterals using CT data.

Small remnant liver volume after right lobe living donor hepatectomy

Right lobe living donor liver transplantation has become a viable option for adult patients with end-stage liver disease, however, the safety of the donor is of paramount importance. One of the key factors in donor safety is ensuring adequate donor remnant liver volume. We retrospectively examined donors who had less than 30% remnant liver volume after right graft procurement. Eighty-six right lobe living donor transplants were carried out in Chang Gung Memorial Hospital, Kaohsiung Medical Center, from January 1999 to December 2004. Eight donors had less than 30% remnant liver volume (Group 1) after graft procurement and 78 donors had remnant liver volume greater than 30% (Group 2). There were no differences in donor characteristics, types of graft, operative parameters, and post-operative liver and renal function as well as liver volume at 6 months post-donation between the 2 groups. The graft weight obtained in Group 1 donors was significantly greater compared with that from Group 2 (P<.005). The overall donor complication rate was 6.98%, and all the complications occurred among group 2 donors. The judicious use of donors with less than 30% remnant liver volume is safe as a last resort.

Liver regeneration and surgical outcome in donors of right-lobe liver grafts.

Previous studies of healthy live-liver donors have suggested that complete liver regeneration occurs within a matter of weeks; however, there have been no long-term studies evaluating liver regeneration and few studies documenting long-term donor outcome. Fifty-one donors who provided right-lobe grafts underwent volumetric spiral computed tomography scans preoperatively and postoperatively at time intervals of 1 week and 1, 3, 6, and 12 months. Patient demographics, surgical data, and postoperative outcome were correlated with liver regeneration data. Donor surgical outcome was followed prospectively and recorded in a comprehensive database. Thirty-three males and 18 females (mean age 36.0+/-9.6 years) provided 51 right-lobe grafts. Mean follow-up was 9.8+/-3.4 months. No donor operation was aborted, and surgical morbidity and mortality rates were 39% and 0%, respectively. Donor remnant liver volume was 49.4+/-5.7% of the original total liver volume (TLV). Overall liver regeneration was 83.3+/-9.0% of the TLV by 1 year. Female donors had significantly slower liver regrowth when compared with males at 12 months (79.8+/-9.3% vs. 85.6+/-8.2%, P<0.01). There was no effect of age, body mass index, operative time, estimated blood loss, postoperative complications, or perioperative liver function tests on liver regeneration. Liver regeneration continues throughout the first postoperative year. Only one donor achieved complete liver regeneration during this time period; however, all donors have maintained normal liver function without long-term complications. Longer follow-up is needed to determine whether donors ever achieve original TLV.

Significant role of middle hepatic vein in remnant liver regeneration of right-lobe living donors.

For adult patients with end-stage liver disease, living-donor liver transplantation (LDLT) of right-lobe grafts with or without the middle hepatic vein (MHV) has been increasingly used in recent years. We investigated the role of the MHV in donor remnant liver regeneration after right-lobe LDLT, which has not been described in previous studies. A total of eight living donors were included in this study of right-lobe LDLT. Four donors underwent right lobectomy (without MHV), and the remaining four underwent extended right lobectomy (with MHV). Regeneration of the donor remnant liver was assessed by volumetric computed tomography studies before and 90 days after LDLT. Comparison between the right-lobe and extended right-lobe donors did not show a clear-cut difference in the net increase of remnant liver volume at 3 months. However, the mean volume increase of the medial segment at the 90th postoperative day was 7% in the extended right-lobe donors and 61% in the right-lobe donors, showing a lower value in the remnant livers without MHV. The MHV plays a specific role in remnant liver regeneration of right-lobe living donors. We expect that this knowledge will contribute to securing a margin of safety in right-lobe LDLT.

Analysis of Donor Risk in Living‐Donor Hepatectomy: The Impact of Resection Type on Clinical Outcome

The progressive shortage of liver donors has mandated investigation of living-donor transplantation (LDT). Concerns about increasing risk to the donor are evident, but the impact of the degree of parenchymal loss has not been quantified. We analyzed clinical and biological variables in 45 LDT performed by our team over 2years to assess risks faced in adult LDT. All donors are alive and well with complete follow-up through to February 2001. When the three operations were compared, right hepatectomy (RH) was significantly longer in terms of anesthesia time and blood loss compared with left hepatectomy (LH) and left lobectomy (LL). Donor remnant liver was significantly reduced after RH compared with LH and LL. There were significant functional differences as a consequence of the remnant size, measured by an increase in peak prothrombin time after RH. RH for adults represents a markedly different insult from pediatric donations in terms of parenchymal loss and early functional impairment. Left hepatectomy donation offers modest advantage over right lobes but seems to confer substantial technical risk for a small gain in graft size. Unless novel strategies are developed to enhance liver function of the LH graft in the adult recipient, right lobe donation will be necessary for adult LDT.