Determination of the safe range of graft size mismatch using body surface area index in deceased liver transplantation

Graft reduction in adult liver transplantation: indications, techniques, and outcomes

PURPOSE

Graft reduction can be a patient's graft-saving option to avoid large-for-size (LFS) syndrome. This study aimed to summarize the literature on graft reduction in adult liver transplantation and to demonstrate the technique of H67 graft hepatectomy.

METHODS

The technique, shown in a didactical video, entails an ex situ posterior sectionectomy under hypothermic perfusion. The right hepatic vein is identified, and the transection line follows the right hepatic fissure. The Glissonean pedicles are ligated during parenchymal transection.

RESULTS

A narrative review of the literature yielded 7 studies. A total of 15 liver grafts were reduced in adult liver transplantations. Most of the reductions were ex situ (11/15 [73.3%]). Graft reduction entailed an H67 sectionectomy in 10 cases and an H23 sectionectomy in 1 case. In situ reduction included 1 right hepatectomy (H5678), 2 H67 sectionectomies, and 1 H23 left lateral sectionectomy. The duration of the ex situ reduction averaged 56 minutes (median: 40.5 minutes; IQR, 33.0-130.0), and the graft weight-to-recipient weight ratio decreased from 3.57% ± 0.40% to 2.70% ± 0.50% after graft reduction. The average cold ischemia time was 390 minutes (IQR, 230-570). There was no liver retransplantation.

CONCLUSION

Graft reduction in adult liver transplantation may be necessary to avoid LFS syndrome. Ex-situ H67 posterior sectionectomy represents the easiest graft reduction hepatectomy and is able to minimize the occurrence of graft compression while leaving enough functional liver parenchyma.

Evaluating the Correlation Between Anteroposterior Diameter, Body Surface Area, and Height for Liver Transplant Donors and Recipients

Background

Small stature and female sex correlate to decreased deceased donor liver transplant (DDLT) access and higher waitlist mortality. However, efforts are being made to improve access and equity of allocation under the new continuous distribution (CD) system. Liver anteroposterior diameter (APD) is a method used by many centers to determine size compatibility for DDLT but is not recorded systematically, so it cannot be used for allocation algorithms. We therefore seek to correlate body surface area (BSA) and height to APD in donors and recipients and compare waitlist outcomes by these factors to support their use in the CD system.

Methods

APD was measured from single-center DDLT recipients and donors with cross-sectional imaging. Linear, Pearson, and PhiK correlation coefficient were used to correlate BSA and height to APD. Competing risk analysis of waitlist outcomes was performed using United Network for Organ Sharing data.

Results

For 143 pairs, donor BSA correlated better with APD than height (PhiK = 0.63 versus 0.20). For recipient all comers, neither BSA nor height were good correlates of APD, except in recipients without ascites, where BSA correlated well (PhiK = 0.63) but height did not. However, among female recipients, BSA, but not height, strongly correlated to APD regardless of ascites status (PhiK = 0.80 without, PhiK = 0.70 with). Among male recipients, BSA correlated to APD only in those without ascites (PhiK = 0.74). In multivariable models, both BSA and height were predictive of waitlist outcomes, with higher values being associated with increased access, decreased delisting for death/clinical deterioration, and decreased living donor transplant (model concordance 0.748 and 0.747, respectively).

Conclusions

Taken together, BSA is a good surrogate for APD and can therefore be used in allocation decision making in the upcoming CD era to offset size and gender-based disparities among certain candidate populations.

Size Matching Deceased Donor Livers: The Tampa General Measurement System

BACKGROUND

No reliable or standardized system exists for measuring the size of deceased donor livers to determine whether they will fit appropriately into intended recipients.

METHODS

This retrospective, single-center study evaluated the efficacy of Tampa General Hospital's size-matching protocol for consecutive, deceased donor liver transplantations between October 2021 and November 2022. Our protocol uses cross-sectional imaging at the time of organ offer to compare the donor's right hepatic lobe size with the recipient's right hepatic fossa. Outcomes were analyzed, including large-for-size syndrome, small-for-size syndrome, early allograft dysfunction, primary nonfunction, graft survival, and patient survival.

RESULTS

We included 171 patients in the study. The donor liver physically fit in all the patients except one whose pretransplant imaging was outdated. One patient (0.6%) had large-for-size syndrome, none had small-for-size syndrome, 15 (10%) had early allograft dysfunction, and none had primary nonfunction. There were 11 (7%) patient deaths and 11 (7%) graft failures.

CONCLUSION

Our measurement system is fast and effective. It reliably predicts whether the donor liver will fit in the intended recipient and is associated with low rates of early allograft dysfunction.

From large-for-size to large-for-flow: A paradigm shift in liver transplantation

Liver graft-recipient matching remains challenging, and both morphologic and hemodynamic characteristics have been shown to be relevant indicators of post-transplant outcomes. However, no combined analysis is available to date. To study the impact of both morphologic and hemodynamic characteristics of liver grafts on transplantation outcomes, we retrospectively evaluated all consecutive 257 liver transplantations with prospective hemodynamic measurements from 2017 to 2020 in a single-center perspective. First, a morphologic analysis compared recipients with or without large-for-size (LFS), defined by a graft/recipient weight ratio >2.5% and excluding extreme LFS. Second, a hemodynamic analysis compared recipients with or without low portal flow (LPF; <80 mL/min per 100 g of liver tissue). Third, an outcome analysis combining LPF and LFS was performed, focusing on liver graft-related morbidity (LGRM), graft and patient survival. LGRM was a composite endpoint, including primary nonfunction, high-risk L-Graft7 category, and portal vein thrombosis. Morphologic analysis showed that LFS (n=33; 12.9%) was not associated with an increased LGRM (12.1% vs 9.4%; p =0.61) or impaired graft and patient survival. However, the hemodynamic analysis showed that LPF (n=43; 16.8%) was associated with a higher LGRM (20.9% vs 7.5%, p = 0.007) and a significantly impaired 90-day graft and patient survival. Multivariable analysis identified LPF but not LFS as an independent risk factor for LGRM (OR: 2.8%; CI:1.088-7.413; and p = 0.03), 90-day (HR: 4%; CI: 1.411-11.551; and p = 0 .01), and 1-year patient survival. LPF is a significant predictor of post-liver transplantation morbi-mortality, independent of LFS when defined as a morphologic metric alone. Consequently, we propose the novel concept of large-for-flow, which may guide graft selection and improve perioperative management of LPF.

Role of intelligent/interactive qualitative and quantitative analysis-three-dimensional estimated model in donor-recipient size mismatch following deceased donor liver transplantation

BACKGROUND

Donor-recipient size mismatch (DRSM) is considered a crucial factor for poor outcomes in liver transplantation (LT) because of complications, such as massive intraoperative blood loss (IBL) and early allograft dysfunction (EAD). Liver volumetry is performed routinely in living donor LT, but rarely in deceased donor LT (DDLT), which amplifies the adverse effects of DRSM in DDLT. Due to the various shortcomings of traditional manual liver volumetry and formula methods, a feasible model based on intelligent/interactive qualitative and quantitative analysis-three-dimensional (IQQA-3D) for estimating the degree of DRSM is needed.

AIM

To identify benefits of IQQA-3D liver volumetry in DDLT and establish an estimation model to guide perioperative management.

METHODS

We retrospectively determined the accuracy of IQQA-3D liver volumetry for standard total liver volume (TLV) (sTLV) and established an estimation TLV (eTLV) index (eTLVi) model. Receiver operating characteristic (ROC) curves were drawn to detect the optimal cut-off values for predicting massive IBL and EAD in DDLT using donor sTLV to recipient sTLV (called sTLVi). The factors influencing the occurrence of massive IBL and EAD were explored through logistic regression analysis. Finally, the eTLVi model was compared with the sTLVi model through the ROC curve for verification.

RESULTS

A total of 133 patients were included in the analysis. The Changzheng formula was accurate for calculating donor sTLV (P = 0.083) but not for recipient sTLV (P = 0.036). Recipient eTLV calculated using IQQA-3D highly matched with recipient sTLV (P = 0.221). Alcoholic liver disease, gastrointestinal bleeding, and sTLVi > 1.24 were independent risk factors for massive IBL, and drug-induced liver failure was an independent protective factor for massive IBL. Male donor-female recipient combination, model for end-stage liver disease score, sTLVi ≤ 0.85, and sTLVi ≥ 1.32 were independent risk factors for EAD, and viral hepatitis was an independent protective factor for EAD. The overall survival of patients in the 0.85 < sTLVi < 1.32 group was better compared to the sTLVi ≤ 0.85 group and sTLVi ≥ 1.32 group (P < 0.001). There was no statistically significant difference in the area under the curve of the sTLVi model and IQQA-3D eTLVi model in the detection of massive IBL and EAD (all P > 0.05).

CONCLUSION

IQQA-3D eTLVi model has high accuracy in predicting massive IBL and EAD in DDLT. We should follow the guidance of the IQQA-3D eTLVi model in perioperative management.

Maximizing utility of nondirected living liver donor grafts using machine learning

Objective

There is an unmet need for optimizing hepatic allograft allocation from nondirected living liver donors (ND-LLD).

Materials and method

Using OPTN living donor liver transplant (LDLT) data (1/1/2000-12/31/2019), we identified 6328 LDLTs (4621 right, 644 left, 1063 left-lateral grafts). Random forest survival models were constructed to predict 10-year graft survival for each of the 3 graft types.

Results

Donor-to-recipient body surface area ratio was an important predictor in all 3 models. Other predictors in all 3 models were: malignant diagnosis, medical location at LDLT (inpatient/ICU), and moderate ascites. Biliary atresia was important in left and left-lateral graft models. Re-transplant was important in right graft models. C-index for 10-year graft survival predictions for the 3 models were: 0.70 (left-lateral); 0.63 (left); 0.61 (right). Similar C-indices were found for 1-, 3-, and 5-year graft survivals. Comparison of model predictions to actual 10-year graft survivals demonstrated that the predicted upper quartile survival group in each model had significantly better actual 10-year graft survival compared to the lower quartiles (p<0.005).

Conclusion

When applied in clinical context, our models assist with the identification and stratification of potential recipients for hepatic grafts from ND-LLD based on predicted graft survivals, while accounting for complex donor-recipient interactions. These analyses highlight the unmet need for granular data collection and machine learning modeling to identify potential recipients who have the best predicted transplant outcomes with ND-LLD grafts.

Optimizing graft-recipient size matching in adolescent liver transplantation: Don't forget ex situ right posterior sectionectomy

BACKGROUND

Graft-recipient size matching is a major challenge in pediatric liver transplantation, especially for adolescent recipients. Indeed, adolescents have the lowest transplantation rate among pediatric recipients, despite prioritization policies and the use of split grafts. In case of an important graft-recipient size mismatch, ex situ graft reduction with right posterior sectionectomy (RPS) may optimize the available donor pool to benefit adolescent recipients.

METHODS

We present three cases of liver graft reduction with ex situ RPS for adolescent recipients. The surgical strategy was guided by GRWR (graft/recipient weight ratio), GW/RAP (right anteroposterior distance ratio), and CT-scan volumetric and anthropometric evaluation.

RESULTS

Recipients were 12, 13, and 14-year-old and weighed 32, 47, and 35 kg, respectively. All liver grafts were procured from brain-dead donors with a donor/recipient weight ratio >1.5. RPS was performed ex situ, removing 20% of the total liver volume leading to a decrease of the GRWR <4% and the GW/RAP <100 g/cm in each case. All three reduced grafts were successfully transplanted with a static cold storage time ranging from 390 to 510 min without the need for delayed abdominal closure. We did not observe any primary non-function, vascular complication, or delayed graft function with a median follow-up of 6 months. One biliary anastomotic stenosis occurred which required surgical treatment.

CONCLUSION

Ex situ liver graft reduction with RPS allowed for successful transplantation in case of anthropometric graft-recipient size mismatch in adolescent liver transplant candidates. Although the use of split grafts remains the gold standard, RPS should be acknowledged as a way to optimize the donor pool, especially for adolescent recipients.

Donor-Recipient Body Surface Area Mismatch and the Outcome of Liver Transplantation in the UK

Introduction: Too small or too big liver grafts for recipient's size has detrimental effects on transplant outcomes. Research Questions: The purpose was to correlate donor-recipient body surface area ratio or body surface area index with recipient survival, graft survival, hepatic artery or portal vein, or vena cava thrombosis. High and low body surface area index cut-off points were determined. Design: There were 11,245 adult recipients of first deceased donor whole liver-only grafts performed in the UK from January 2000 until June 2020. The transplants were grouped according to the body surface area index and compared to complications, graft and recipient survival. Results: The body surface area index ranged from 0.491 to 1.691 with a median of 0.988. The body surface area index > 1.3 was associated with a higher rate of portal vein thrombosis within the first 3 months (5.5%). This risk was higher than size-matched transplants (OR: 2.878, 95% CI: 1.292-6.409, P = 0.01). Overall graft survival was worse in transplants with body surface area index ≤ 0.85 (HR: 1.254, 95% CI: 1.051-1.497, P = 0.012) or body surface area index > 1.4 (HR: 3.704, 95% CI: 2.029-6.762, P < 0.001) than those with intermediate values. The graft survival rates were reduced by 2% for cases with body surface area index ≤ 0.85 but were decreased by 20% for cases with body surface area index > 1.4. These findings were confirmed by bootstrap internal validation. No statistically significant differences were detected for hepatic artery thrombosis, occlusion of hepatic veins/inferior vena cava or recipient survival. Conclusions: Donor-recipient size mismatch affects the rates of portal vein thrombosis within the first 3 months and overall graft survival in deceased-donor liver transplants.

Declined Organs for Liver Transplantation: A Right Decision or a Missed Opportunity for Patients with Hepatocellular Carcinoma?

BACKGROUND

Liver transplantation is the only promising treatment for end-stage liver disease and patients with hepatocellular carcinoma. However, too many organs are rejected for transplantation.

METHODS

We analyzed the factors involved in organ allocation in our transplant center and reviewed all livers that were declined for transplantation. Reasons for declining organs for transplantation were categorized as major extended donor criteria (maEDC), size mismatch and vascular problems, medical reasons and risk of disease transmission, and other reasons. The fate of the declined organs was analyzed.

RESULTS

1086 declined organs were offered 1200 times. A total of 31% of the livers were declined because of maEDC, 35.5% because of size mismatch and vascular problems, 15.8% because of medical reasons and risk of disease transmission, and 20.7% because of other reasons. A total of 40% of the declined organs were allocated and transplanted. A total of 50% of the organs were completely discarded, and significantly more of these grafts had maEDC than grafts that were eventually allocated (37.5% vs. 17.7%, p < 0.001).

CONCLUSION

Most organs were declined because of poor organ quality. Donor-recipient matching at time of allocation and organ preservation must be improved by allocating maEDC grafts using individualized algorithms that avoid high-risk donor-recipient combinations and unnecessary organ declination.

Understanding Local Hemodynamic Changes After Liver Transplant: Different Entities or Simply Different Sides to the Same Coin?

Liver transplantation is an extremely complex procedure performed in an extremely complex patient. With a successful technique and acceptable long-term survival, a new challenge arose: overcoming donor shortage. Thus, living donor liver transplant and other techniques were developed. Aiming for donor safety, many liver transplant units attempted to push the viable limits in terms of size, retrieving smaller and smaller grafts for adult recipients. With these smaller grafts came numerous problems, concepts, and definitions. The spotlight is now aimed at the mirage of hemodynamic changes derived from the recipients prior alterations. This article focuses on the numerous hemodynamic syndromes, their definitions, causes, and management and interconnection with each other. The aim is to aid the physician in their recognition and treatment to improve liver transplantation success.

Radiological Screening Methods in Deceased Organ Donation: An Overview of Guidelines Worldwide

Organ transplantation is performed worldwide, but policies regarding donor imaging are not uniform. An overview of the policies in different regions is missing. This study aims to investigate the various protocols worldwide on imaging in deceased organ donation. An online survey was created to determine the current policies. Competent authorities were approached to fill out the survey based on their current protocols. In total 32 of the 48 countries approached filled out the questionnaire (response rate 67%). In 16% of the countries no abdominal imaging is required prior to procurement. In 50%, abdominal ultrasound (US) is performed to screen the abdomen and in 19% an enhanced abdominal Computed Tomography (CT). In 15% of the countries both an unenhanced abdominal CT scan and abdominal US are performed. In 38% of the countries a chest radiographic (CXR) is performed to screen the thorax, in 28% only a chest CT, and in 34% both are performed. Policies regarding radiologic screening in deceased organ donors show a great variation between different countries. Consensus on which imaging method should be applied is missing. A uniform approach will contribute to quality and safety, justifying (inter)national exchange of organs.

Analysis of factors associated with discrepancies between predicted and observed liver weight in liver transplantation

BACKGROUND

Even using predictive formulas based on anthropometrics in about 30% of subjects, liver weight (LW) cannot be predicted with a ≤20% margin of error. We aimed to identify factors associated with discrepancies between predicted and observed LW.

METHODS

In 500 consecutive liver grafts, we tested LW predictive performance using 17 formulas based on anthropometric characteristics. Hashimoto's formula (961.3 × BSA_D-404.8) was associated with the lowest mean absolute error and used to predict LW for the entire cohort. Clinical factors associated with a ≥20% margin of error were identified in a multivariable analysis after propensity score matching (PSM) of donors with similar anthropometric characteristics.

RESULTS

The total LW was underestimated with a ≥20% margin of error in 53/500 (10.6%) donors and overestimated in 62/500 (12%) donors. After PSM analysis, ages ≥ 65, (OR = 3.21; CI95% = 1.63-6.31; P = .0007), age ≤ 30 years, (OR = 2.92; CI95% = 1.15-7.40; P = .02), and elevated gamma-glutamyltransferase (GGT) levels (OR = 0.98; CI95% = 0.97-0.99; P = .006), influenced the risk of LW overestimation. Age ≥ 65 years, (OR = 5.98; CI95% = 2.28-15.6; P = .0002), intensive care unit (ICU) stay with ventilation > 7 days, (OR = 0.32; CI95% = 0.12-0.85; P = .02) and waist circumference increase (OR = 1.02; CI95% = 1.00-1.04; P = .04) were factors associated with LW underestimation.

CONCLUSIONS

Increased waist circumference, age, prolonged ICU stay with ventilation, elevated GGT were associated with an increase in the margin of error in LW prediction. These factors and anthropometric characteristics could help transplant surgeons during the donor-recipient matching process.

Donor-recipient body size mismatch has no impact on outcomes after deceased donor whole liver transplantation: Role of donor liver size measurement

The role of donor-recipient body size mismatch (DRSM) on outcomes after whole liver transplantation (LT) is not clearly defined. At our center, in presence of considerable DRSM, objective assessment of the donor liver by a radiology or intraoperative evaluation by procuring surgeon was incorporated. To evaluate the impact of DRSM on graft outcomes with this approach, adult deceased donor whole liver transplants between July 2001 and December 2017 at our center were studied. DRSM was considered when the donor-recipient body surface area (BSA) ratio (DR-BSAr) was either <0.69 or >1.25. There were 54 (3.2%) transplants with DR-BSAr <0.69 and 61 (3.6%) with DR-BSAr >1.25. One-year graft survival was 85% vs. 89% vs. 89%; (p = .64) for transplants with DR-BSArs of <0.69, 0.69-1.25, and >1.25, respectively. Early allograft dysfunction (EAD) (28% vs. 27% vs. 37%; p = .07), post-transplant coagulopathy, bilirubinemia, and renal function were also comparable. In conclusion, with the actual measurement of the donor liver and recipient abdominal cavity, significant DRSM did not have a negative impact on early and long-term outcomes. Routine measurement of donor liver size by radiology may be incorporated in liver allocation to improve utilization.

Early outcomes of implanting larger-sized grafts in deceased donor liver transplantation

BACKGROUND

The outcomes of large-sized graft mismatch in deceased donor liver transplantation (LT) have been rarely studied. The aim of this study was to determine whether a large-sized graft for recipient influenced the post-transplant outcomes.

METHODS

A total of 273 patients undergoing LT were enrolled and divided into a large and a normal-sized graft group by graft weight to recipient weight (GWRW) >2.5% (n = 76) or GWRW ≤2.5% (n = 197). Post-operative complications and outcomes were retrospectively analysed.

RESULTS

The two groups were comparable in demographic characteristics. The rate of complications was significantly higher in the large-sized graft group including early allograft dysfunction (36.8% versus 17.8%, P = 0.001), hepatic necrosis (26.3% versus 13.7%, P = 0.01) and massive hydrothorax (25% versus 14.7%, P = 0.04). The large-sized graft group suffered higher early mortality compared with the normal-sized graft group (30 days: 14.5% versus 5.6%, P = 0.02, 90 days: 21.1% versus 9.6%, P = 0.01). The primary causes of early death were multiple organ failure (10.5% versus 2%, P = 0.002) and sepsis (2.6% versus 1.5%, P = 0.54). Four parameters including donor alanine transaminase, GWRW, estimated blood loss and model for end-stage liver disease score were significant on multivariate analysis, and indicated significant risk factors for the early mortality of recipients.

CONCLUSION

In deceased donor LT, GWRW >2.5% is associated with increased liver injury, risk of early mortality and other adverse outcomes. Thus, donor livers should be allocated to recipients with GWRW ≤2.5%.

Quantifying Sex-Based Disparities in Liver Allocation

Importance

Differences in local organ supply and demand have introduced geographic inequities in the Model for End-stage Liver Disease (MELD) score-based liver allocation system, prompting national debate and patient-initiated lawsuits. No study to our knowledge has quantified the sex disparities in allocation associated with clinical vs geographic characteristics.

Objective

To estimate the proportion of sex disparity in wait list mortality and deceased donor liver transplant (DDLT) associated with clinical and geographic characteristics.

Design, Setting, and Participants

This retrospective cohort study used adult (age ≥18 years) liver-only transplant listings reported to the Organ Procurement and Transplantation Network from June 18, 2013, through March 1, 2018.

Exposure

Liver transplant waiting list.

Main Outcomes and Measures

Primary outcomes included wait list mortality and DDLT. Multivariate Cox proportional hazards regression models were constructed, and inverse odds ratio weighting was used to estimate the proportion of disparity across geographic location, MELD score, and candidate anthropometric and liver measurements.

Results

Among 81 357 adults wait-listed for liver transplant only, 36.1% were women (mean [SD] age, 54.7 [11.3] years; interquartile range, 49.0-63.0 years) and 63.9% were men (mean [SD] age, 55.7 [10.1] years; interquartile range, 51.0-63.0 years). Compared with men, women were 8.6% more likely to die while on the waiting list (adjusted hazard ratio [aHR], 1.11; 95% CI, 1.04-1.18) and were 14.4% less likely to receive a DDLT (aHR, 0.86; 95% CI, 0.84-0.88). In the geographic domain, organ procurement organization was the only variable that was significantly associated with increased disparity between female sex and wait list mortality (22.1% increase; aHR, 1.22; 95% CI, 1.09-1.30); no measure of the geographic domain was associated with DDLT. Laboratory and allocation MELD scores were associated with increases in disparities in wait list mortality: 1.14 (95% CI, 1.09-1.19; 50.1% increase among women) and DDLT: 0.87 (95% CI, 0.86-0.88; 10.3% increase among women). Candidate anthropometric and liver measurements had the strongest association with disparities between men and women in wait list mortality (125.8% increase among women) and DDLT (49.0% increase among women).

Conclusions and Relevance

Our findings suggest that addressing geographic disparities alone may not mitigate sex-based disparities, which were associated with the inability of the MELD score to accurately estimate disease severity in women and to account for candidate anthropometric and liver measurements in this study.

Is there an ethical obligation to split every donor liver? Scarce resources, medical factors, and ethical reasoning

SLT has the potential to counter the worldwide shortage of donor organs. Although the preferred recipients of SLT are usually pediatric patients, a more stringent ethical argument than the fundamental prioritization of children is to demonstrate that SLT of deceased donor organs could increase access to this potentially lifesaving resource for all patients, including children. Several empirical studies show that SLT also makes it possible to achieve similar outcomes to WLT in adults if several factors are observed. In general, it can be regarded as ethically permissible to insist on splitting a donor liver if, in an individual case, SLT is expected to have a similar outcome to that of WLT. The question is therefore no longer whether, but under what conditions SLT is able to achieve similar results to WLT. One of the main challenges of the current debate is the restricted comparability of the available data. We therefore have an ethical obligation to improve the available empirical data by implementing prospective clinical studies, SLT programs, and national registries. The introduction of 2 modes of allocation-one for patients willing to accept both SLT and WLT, and a second for patients only willing to accept WLT-would help to resolve the issue of patient autonomy in the case of mandatory splitting policy.

Extreme large-for-size syndrome after adult liver transplantation: A model for predicting a potentially lethal complication

There is currently no tool available to predict extreme large-for-size (LFS) syndrome, a potentially disastrous complication after adult liver transplantation (LT). We aimed to identify the risk factors for extreme LFS and to build a simple predictive model. A cohort of consecutive patients who underwent LT with full grafts in a single institution was studied. The extreme LFS was defined by the impossibility to achieve direct fascial closure, even after delayed management, associated with early allograft dysfunction or nonfunction. Computed tomography scan-based measurements of the recipient were done at the lower extremity of the xiphoid. After 424 LTs for 394 patients, extreme LFS occurred in 10 (2.4%) cases. The 90-day mortality after extreme LFS was 40.0% versus 6.5% in other patients (P = 0.003). In the extreme LFS group, the male donor-female recipient combination was more often observed (80.0% versus 17.4%; P < 0.001). The graft weight (GW)/right anteroposterior (RAP) distance ratio was predictive of extreme LFS with the highest area under the curve (area under the curve, 0.95). The optimal cutoff was 100 (sensitivity, 100%; specificity, 88%). The other ratios based on height, weight, body mass index, body surface area, and standard liver volume exhibited lower predictive performance. The final multivariate model included the male donor-female recipient combination and the GW/RAP. When the GW to RAP ratio increases from 80, 100, to 120, the probability of extreme LFS was 2.6%, 9.6%, and 29.1% in the male donor-female recipient combination, and <1%, 1.2%, and 4.5% in other combinations. In conclusion, the GW/RAP ratio predicts extreme LFS and may be helpful to avoid futile refusal for morphological reasons or to anticipate situation at risk, especially in female recipients. Liver Transplantation 23 1294-1304 2017 AASLD.

Exception Points and Body Size Contribute to Gender Disparity in Liver Transplantation

BACKGROUND & AIMS

Women are significantly less likely than men to receive a liver transplant and more likely to die on the waitlist. We investigated potential reasons for these disparities, including match run positioning and organ declines caused by small stature of female recipients.

METHODS

We analyzed data from the United Network of Organ Sharing registry of candidates placed on the waitlist from May 10, 2007, through June 17, 2013. Primary outcomes included ranked in first position on a match run, having an organ declined while in first position, declining an organ while in first position because of size mismatch between donor and recipient (body surface area discordance), and death or becoming too sick for liver transplantation.

RESULTS

Among 64,995 patients on the waitlist for liver transplantation, 23.1% of men and 15.6% of women received exception points (P < .001). Women listed without exception points were less likely than men to be ranked first (odds ratio [OR], 0.93; 95% CI, 0.88-0.99). Women who achieved first position were more likely to decline an organ than men (OR, 1.15; 95% CI, 1.06-1.26); this difference was reduced after we accounted for recipient body surface area (OR, 1.08; 95% CI, 0.98-1.19). Women with a single organ decline were more likely than men with a single organ decline to die or become too sick for transplantation (OR, 1.26; 95% CI, 1.12-1.41). The difference was reduced after we accounted for exception points (OR, 1.16; 95% CI, 1.12-1.21) and recipient body surface area (OR, 1.01; 95% CI, 0.96-1.06).

CONCLUSIONS

In an analysis of data from the United Network of Organ Sharing registry, we found that women when compared with men on the waitlist for liver transplantation are disadvantaged by an imbalance in exception point allocation and organ declines because of small stature.

In Situ Posterior Graft Segmentectomy for Large-for-Size Syndrome in Deceased Donor Liver Transplantation in Adults: A Case Report

Large-for-size syndrome (LFSS) is controversial in pediatric living donor liver transplantation patients and is associated with a poor graft outcome. Similar situations in deceased donor liver transplantation (DDLT) in adults have not been reported frequently, and there are no official guidelines worldwide. Deceased donation is extremely limited in Japan, and when a larger liver is allocated for a very sick small recipient in Japan, transplantation with a plan to address LFSS might be necessary. The patient is a 58-year-old female patient who had acute liver failure with coma. The graft-recipient weight ratio (GRWR) was 2.74%. Although the graft was enlarged by reperfusion, the intraoperative Doppler ultrasound, performed after reperfusion, showed sufficient graft in-flow and out-flow. However, when the liver graft was situated appropriately into the right phrenic space supported by the rib cage and diaphragm, the blood flow in the hepatic vein and portal vein was significantly reduced. Graft blood flow did not improve without removing it from the right subphrenic space. Therefore, we decided to perform an in situ graft posterior segmentectomy, so that the graft right lobe was properly accommodated in the patient's right subphrenic space. After the segmentectomy of the graft, an intraoperative Doppler sonogram showed significantly improved blood flow. LFSS could be a significant operative challenge in adult DDLT, especially in areas with limited chances of DDLT. In situ posterior segmentectomy in the demarcated area could be a solution for treating patients with LFSS.

Size mismatch in liver transplantation

Size mismatch is an unique and inevitable but critical issue in live donor liver transplantation. Unmatched metabolic demand of recipient as well as physiologic mismatch aggravates the damage to liver graft, inevitably leading to graft failure on recipient. Also, an excessive resection of liver graft for better recipient outcome in live donor liver transplant may jeopardize the healthy donor well-being and even put donor life in danger. There is a fine balance between resected graft volume required to meet the recipient's metabolic demand and residual graft volume required for donor safety. The obvious clinical necessity of finding that balance has prompted a clinical need and promoted the improvement of knowledge and development of management strategies for size-mismatched transplants. The development of the size-matching methodology has significantly improved graft outcome and recipient survival in live donor liver transplants. On the other hand, the effect of size mismatch in cadaveric transplants has never been observed as being so pronounced. The importance of matching of the donor recipient size has been unrecognized in cadaveric liver transplant. In this review, we attempt to summarize the current most updated knowledge on the subject, particularly addressing the definition and complications of size-mismatched cadaveric liver transplant, as well as management strategies.

Comparison of two different formulas for body surface area in adults at extremes of height and weight

Background

Different equations for predicting body surface area have been derived. The DuBois and Mosteller body surface area equations are considered equivalent, but the accuracy in adult patients at extremes of height and weight is unknown.

Purpose

To compare body surface area in patients at extremes of height and weight using both formulas to determine whether a difference affected chemotherapy dose.

Methods

Anthropometric data were extracted from the 2012 Centers for Disease Control and Prevention Vital and Health Statistics. Data for both males and females were examined. The 50th percentiles of weight and height were used to calculate the body surface area with both formulas. Calculations were repeated using the 5th through 95th percentiles for weight, then the 5th through 95th percentiles for height, and so forth until all extremes of height and weight were examined. Each body surface area was used to calculate a chemotherapy dose. A difference of ≥4.5% in dose was considered clinically significant.

Results

Differences were apparent in both males and females. Dosing differences were most apparent in patients in the 50th, 75th or 95th percentile for both height and weight. Differences are also noted in other percentiles, suggesting that patients of smaller stature may also be affected.

Conclusion

Guidelines recommend full doses of chemotherapy for patients with curative intent but do not specify which body surface area formula is preferred. Our results imply that the Mosteller equation provides a greater chemotherapy dose, and this difference may be clinically significant in patients who are in the 50th to 95th percentiles for height, weight or both. Further study is necessary to validate these results and determine the impact on patient outcomes.

Using ultrasonography to monitor liver blood flow for liver transplant from donors supported on extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) has been used to support brain-dead donors for liver procurement. This study investigated the potential role of ultrasonographic monitoring of hepatic perfusion as an aid to improve the viability of liver transplants obtained from brain-dead donors who are supported on ECMO. A total of 40 brain-dead patients maintained on ECMO served as the study population. Hepatic blood flow was monitored using ultrasonography, and perioperative optimal perfusion was maintained by calibrating ECMO. Liver function tests were performed to assess the viability of the graft. The hepatic arterial blood flow was well maintained with no significant changes observed before and after ECMO (206 ± 32 versus 241 ± 45 mL/minute; P = 0.06). Similarly, the portal venous blood flow was also maintained throughout (451 ± 65 versus 482 ± 77 mL/minute; P = 0.09). No significant change in levels of total bilirubin, alanine transaminase, and lactic acid were reported during ECMO (P = 0.17, P = 0.08, and P = 0.09, respectively). Before the liver is procured, ultrasonographic monitoring of hepatic blood flow could be a valuable aid to improve the viability of a liver transplant by allowing for real-time calibration of ECMO perfusion in brain-dead liver donors. In our study, ultrasonographic monitoring helped prevent warm ischemic injury to the liver graft by avoiding both overperfusion and underperfusion of the liver.

Influence of graft size matching on outcomes of infantile living donor liver transplantation

We aimed to assess the impact of size mismatching between grafts and recipients on outcomes of infants or small children after LDLT. Between October 2006 and December 2014, 129 LDLT recipients weighing no more than 8 kg were retrospectively analyzed. The entire cohort was categorized into three groups by GRWR: GRWR < 3.0% (group A, n = 38), 3.0% ≤ GRWR < 4.0% (group B, n = 61), and GRWR ≥ 4.0% (group C, n = 30). Baseline characteristics were similar among groups A, B, and C. Compared with groups A and B, post-transplant alanine aminotransferase and aspartate aminotransferase within seven days were significantly higher in group C; however, differences between total bilirubin and albumin after transplantation were not prominent. Moreover, incidences of surgical complications, perioperative deaths, infections, and acute rejections were all comparable among the three groups. Five-yr patient survival rates for groups A, B, and C were 89.5%, 88.9%, and 81.6%, respectively (p = 0.872), and the graft survival rates were 89.5%, 86.6%, and 81.6%, respectively (p = 0.846). In conclusion, GRWR between 1.9% and 5.8% would not cause noticeable adverse events for infantile LDLT recipients ≤ 8 kg. However, there is still a role for considering reduction in the graft mass as an applicable strategy in selected cases.

A novel objective method for deceased donor and recipient size matching in liver transplantation

Although the consequences of implantation of a large whole liver graft into a small recipient such as compression and compromise of graft perfusion are well known, no accepted measure to aid in donor-to-recipient size matching exists. Donor liver graft and recipient native liver weights as well as donor and recipient size and amount of ascites were investigated in 1953 patients who underwent liver transplantation using deceased donor grafts between January 2002 and July 2013. We used a previously described formula for liver resections (standardized total liver volume [sTLV] = -794.41 + 1267.28 × body surface area [m(2)]) for calculating sTLV, in the current cohort of deceased liver donors. Early allograft dysfunction (EAD) and graft survival were the primary outcome measures. The formula for calculating sTLV for liver resections was validated as an accurate predictor of liver volume in the current cohort of deceased liver donors (r(2) = 0.45; P < 0.001). A cutoff point of sTLV ratio ≥ 1.25 was determined through receiver operating characteristic curves, and patients were dichotomized into 2 groups. In the sTLV ratio ≥ 1.25 group, 50% of patients developed EAD compared to 25% of patients in the sTLV ratio < 1.25 group (P < 0.001). The proportion of patients developing graft failure within 90 days was 9.6% in the sTLV ratio ≥ 1.25 group and 5.4% in the sTLV ratio < 1.25 group (P = 0.045). This study validates the use of the sTLV for prediction of actual donor liver weight in the transplant setting. Using this formula, donors with a calculated sTLV size ratio ≥ 1.25 have an increased risk of EAD and therefore caution should be used when that value is exceeded. This adjusted size ratio can be used as a decision aid when considering donor and recipient matching with potential liver organ offers.

Negative wound therapy to manage large-for-size liver graft mismatch

Liver volume matching in liver transplantation (LT) is of paramount importance. There is no agreement for its definition, ranging from a graft-to-recipient-weight-ratio greater than 4% in paediatric to less than 2.5% in adult LT. Advances have been obtained to avoid small for size grafts, but management of large grafts remains a major challenge in this setting. Consequences include difficult anastomosis, poor vascular alignment, difficult wound closure, graft compression and necrosis. We report on two patients who underwent LT with large grafts and develop major liver graft injury. Technical solutions used in these two cases are presented and discussed. Negative wound therapy allowed a rapid closure of abdominal wall and salvage of the graft.

Accuracy of estimation of graft size for living-related liver transplantation: first results of a semi-automated interactive software for CT-volumetry

OBJECTIVES

To evaluate accuracy of estimated graft size for living-related liver transplantation using a semi-automated interactive software for CT-volumetry.

MATERIALS AND METHODS

Sixteen donors for living-related liver transplantation (11 male; mean age: 38.2±9.6 years) underwent contrast-enhanced CT prior to graft removal. CT-volumetry was performed using a semi-automated interactive software (P), and compared with a manual commercial software (TR). For P, liver volumes were provided either with or without vessels. For TR, liver volumes were provided always with vessels. Intraoperative weight served as reference standard. Major study goals included analyses of volumes using absolute numbers, linear regression analyses and inter-observer agreements. Minor study goals included the description of the software workflow: degree of manual correction, speed for completion, and overall intuitiveness using five-point Likert scales: 1--markedly lower/faster/higher for P compared with TR, 2--slightly lower/faster/higher for P compared with TR, 3--identical for P and TR, 4--slightly lower/faster/higher for TR compared with P, and 5--markedly lower/faster/higher for TR compared with P.

RESULTS

Liver segments II/III, II-IV and V-VIII served in 6, 3, and 7 donors as transplanted liver segments. Volumes were 642.9±368.8 ml for TR with vessels, 623.8±349.1 ml for P with vessels, and 605.2±345.8 ml for P without vessels (P<0.01). Regression equations between intraoperative weights and volumes were y = 0.94x+30.1 (R2 = 0.92; P<0.001) for TR with vessels, y = 1.00x+12.0 (R2 = 0.92; P<0.001) for P with vessels, and y = 1.01x+28.0 (R2 = 0.92; P<0.001) for P without vessels. Inter-observer agreement showed a bias of 1.8 ml for TR with vessels, 5.4 ml for P with vessels, and 4.6 ml for P without vessels. For the degree of manual correction, speed for completion and overall intuitiveness, scale values were 2.6±0.8, 2.4±0.5 and 2.

CONCLUSIONS

CT-volumetry performed with P can predict accurately graft size for living-related liver transplantation while improving workflow compared with TR.

Peak Serum AST Is a Better Predictor of Acute Liver Graft Injury after Liver Transplantation When Adjusted for Donor/Recipient BSA Size Mismatch (ASTi)

Background. Despite the marked advances in the perioperative management of the liver transplant recipient, an assessment of clinically significant graft injury following preservation and reperfusion remains difficult. In this study, we hypothesized that size-adjusted AST could better approximate real AST values and consequently provide a better reflection of the extent of graft damage, with better sensitivity and specificity than current criteria. Methods. We reviewed data on 930 orthotopic liver transplant recipients. Size-adjusted AST (ASTi) was calculated by dividing peak AST by our previously reported index for donor-recipient size mismatch, the BSAi. The predictive value of ASTi of primary nonfunction (PNF) and graft survival was assessed by receiver operating characteristic curve, logistic regression, Kaplan-Meier survival, and Cox proportional hazard model. Results. Size-adjusted peak AST (ASTi) was significantly associated with subsequent occurrence of PNF and graft failure. In our study cohort, the prediction of PNF by the combination of ASTi and PT-INR had a higher sensitivity and specificity compared to current UNOS criteria. Conclusions. We conclude that size-adjusted AST (ASTi) is a simple, reproducible, and sensitive marker of clinically significant graft damage.