Safety and feasibility of chemotherapy followed by liver transplantation for patients with definitely unresectable colorectal liver metastases: insights from the TransMet randomised clinical trial.

Background: Despite the increasing efficacy of chemotherapy (C), the 5-year survival rate for patients with unresectable colorectal liver metastases (CLM) remains around 10%. Liver transplantation (LT) might offer a curative approach for patients with liver-only disease, yet its superior efficacy compared to C alone remains to be demonstrated. Methods: The TransMet randomised multicentre clinical trial (NCT02597348) compares the curative potential of C followed by LT versus C alone in patients with unresectable CLM despite stable or responding disease on C. Patient eligibility criteria proposed by local tumour boards had to be validated by an independent committee via monthly videoconferences. Outcomes reported here are from a non-specified interim analysis. These include the eligibility of patients to be transplanted for non resectable colorectal liver metastases, as well as the feasibility and the safety of liver transplantation in this indication. Findings: From February 2016 to July 2021, 94 (60%) of 157 patients from 20 centres in 3 countries submitted to the validation committee, were randomised. Reasons for ineligibility were mainly tumour progression in 50 (32%) or potential resectability in 13 (8%). The median delay to LT after randomisation was 51 (IQR 30-65) days. Nine of 47 patients (19%, 95% CI: 9-33) allocated to the LT arm failed to undergo transplantation because of intercurrent disease progression. Three of the 38 transplanted patients (8%) were re-transplanted, one of whom (3%) died post-operatively from multi-organ failure. Interpretation: The selection process of potential candidates for curative intent LT for unresectable CLM in the TransMet trial highlighted the critical role of an independent multidisciplinary validation committee. After stringent selection, the feasibility of LT was 81%, as 19% had disease progression while on the waiting list. These patients should be given high priority for organ allocation to avoid dropout from the transplant strategy. Funding: No source of support or funding from any author to disclose for this work. The trial was supported by the Assistance Publique - Hôpitaux de Paris (AP-HP).

Post-hepatectomy liver failure: A timeline centered review.

BACKGROUND: Post-hepatectomy liver failure (PHLF) is a leading cause of postoperative mortality after liver surgery. Due to its significant impact, it is imperative to understand the risk stratification and preventative strategies for PHLF. The main objective of this review is to highlight the role of these strategies in a timeline centered way around curative resection. DATA SOURCES: This review includes studies on both humans and animals, where they addressed PHLF. A literature search was conducted across the Cochrane Library, Embase, MEDLINE/PubMed, and Web of Knowledge electronic databases for English language studies published between July 1997 and June 2020. Studies presented in other languages were equally considered. The quality of included publications was assessed using Downs and Black's checklist. The results were presented in qualitative summaries owing to the lack of studies qualifying for quantitative analysis. RESULTS: This systematic review with 245 studies, provides insight into the current prediction, prevention, diagnosis, and management options for PHLF. This review highlighted that liver volume manipulation is the most frequently studied preventive measure against PHLF in clinical practice, with modest improvement in the treatment strategies over the past decade. CONCLUSIONS: Remnant liver volume manipulation is the most consistent preventive measure against PHLF.

Digital twin demonstrates significance of biomechanical growth control in liver regeneration after partial hepatectomy.

Partial liver removal is an important therapy option for liver cancer. In most patients within a few weeks, the liver is able to fully regenerate. In some patients, however, regeneration fails with often severe consequences. To better understand the control mechanisms of liver regeneration, experiments in mice were performed, guiding the creation of a spatiotemporal 3D model of the regenerating liver. The model represents cells and blood vessels within an entire liver lobe, a macroscopic liver subunit. The model could reproduce the experimental data only if a biomechanical growth control (BGC)-mechanism, inhibiting cell cycle entrance at high compression, was taken into account and predicted that BGC may act as a short-range growth inhibitor minimizing the number of proliferating neighbor cells of a proliferating cell, generating a checkerboard-like proliferation pattern. Model-predicted cell proliferation patterns in pigs and mice were found experimentally. The results underpin the importance of biomechanical aspects in liver growth control.

Liver Transplantation Using Allografts With Recent Liver Blunt Trauma: A Nationwide Audit From the French CRISTAL Biomedicine Agency Registry.

BACKGROUND: In the current setting of organ shortage, brain-dead liver donors with recent liver trauma (RLT) represent a potential pool of donors. Yet, data on feasibility and safety of liver transplantation (LT) using grafts with RLT are lacking. METHODS: All liver grafts from brain-dead donors with RLT proposed for LT between 2010 and 2018 were identified from the nationwide CRISTAL registry of the Biomedicine Agency. The current study aimed at evaluating 1-y survival as the primary endpoint. RESULTS: Among 11 073 LTs, 142 LTs (1.3%) using grafts with RLT were performed. These 142 LTs, including 23 split LTs, were performed from 131 donors (46.1%) of 284 donors with RLT proposed for LT. Transplanted grafts were procured from donors with lower liver enzymes levels ( P < 0.001) and less advanced liver trauma according to the American Association for the Surgery of Trauma liver grading system ( P < 0.001) compared with not transplanted grafts. Before allocation procedures, 20 (7%) of 284 donors underwent damage control intervention. During transplantation, specific liver trauma management was needed in 19 patients (13%), consisting of local hemostatic control (n = 15), partial hepatic resection on back-table (n = 3), or perihepatic packing (n = 1). Ninety-day mortality and severe morbidity rates were 8.5% (n = 12) and 29.5% (n = 42), respectively. One-year overall and graft survival rates were 85% and 81%, and corresponding 5-y rates were 77% and 72%, respectively. CONCLUSIONS: Using liver grafts from donors with RLT seems safe with acceptable long-term outcomes. All brain-dead patients with multiorgan trauma, including liver injury, should be considered for organ allocation.

In situ normothermic regional perfusion versus ex situ normothermic machine perfusion in liver transplantation from donation after circulatory death.

In situ normothermic regional perfusion (NRP) and ex situ normothermic machine perfusion (NMP) aim to improve the outcomes of liver transplantation (LT) using controlled donation after circulatory death (cDCD). NRP and NMP have not yet been compared directly. In this international observational study, outcomes of LT performed between 2015 and 2019 for organs procured from cDCD donors subjected to NRP or NMP commenced at the donor center were compared using propensity score matching (PSM). Of the 224 cDCD donations in the NRP cohort that proceeded to asystole, 193 livers were procured, resulting in 157 transplants. In the NMP cohort, perfusion was commenced in all 40 cases and resulted in 34 transplants (use rates: 70% vs. 85% [p = 0.052], respectively). After PSM, 34 NMP liver recipients were matched with 68 NRP liver recipients. The two cohorts were similar for donor functional warm ischemia time (21 min after NRP vs. 20 min after NMP; p = 0.17), UK-Donation After Circulatory Death risk score (5 vs. 5 points; p = 0.38), and laboratory Model for End-Stage Liver Disease scores (12 vs. 12 points; p = 0.83). The incidence of nonanastomotic biliary strictures (1.5% vs. 2.9%; p > 0.99), early allograft dysfunction (20.6% vs. 8.8%; p = 0.13), and 30-day graft loss (4.4% vs. 8.8%; p = 0.40) were similar, although peak posttransplant aspartate aminotransferase levels were higher in the NRP cohort (872 vs. 344 IU/L; p < 0.001). NRP livers were more frequently allocated to recipients suffering from hepatocellular carcinoma (HCC; 60.3% vs. 20.6%; p < 0.001). HCC-censored 2-year graft and patient survival rates were 91.5% versus 88.2% (p = 0.52) and 97.9% versus 94.1% (p = 0.25) after NRP and NMP, respectively. Both perfusion techniques achieved similar outcomes and appeared to match benchmarks expected for donation after brain death livers. This study may inform the design of a definitive trial.

Simultaneous or staged resection for synchronous liver metastasis and primary rectal cancer: a propensity score matching analysis.

BACKGROUND: Colorectal cancer is the third most common cancer in France and by the time of the diagnosis, 15-25% of patients will suffer from synchronous liver metastases. Surgery associated to neoadjuvant treatment can cure these patients, but few studies focus only on rectal cancer. This study was meant to compare the outcomes of patients who underwent a simultaneous resection to those who underwent a staged resection (rectum first or liver first) in the University Hospital of Tours, France. METHODS: We assessed retrospectively a prospective maintained data base about the clinical, pathological and survival outcomes of patients who underwent a simultaneous or a staged resection in our center between 2010 and 2018. A propensity score matching was used, considering the initial characteristics of our groups. RESULTS: There were 70 patients (55/15 males, female respectively) with median age 60 (54-68) years. After matching 48 (69%) of them underwent a staged approach and 22 (31%) a simultaneous approach were compared. After PSM, there were 22 patients in each group. No differences were found in terms of morbidity (p = 0.210), overall survival (p = 0.517) and disease-free survival (p = 0.691) at 3 years after matching. There were significantly less recurrences in the simultaneous group (50% vs 81.8%, p = 0.026). CONCLUSIONS: Simultaneous resection of the rectal primary cancer and synchronous liver metastases is safe and feasible with no difference in terms of survival.

Influence of the ABO Blood Group System on Hepatocellular Carcinoma Recurrence After Liver Transplantation.

BACKGROUND: The ABO blood group system may influence tumorigenesis, but its prognostic value in liver transplantation (LT) for hepatocellular carcinoma (HCC) has never been assessed. METHODS: All consecutive patients who underwent LT for HCC between 2013 and 2017 at 9 centers were analyzed. Predictors of tumor recurrence were identified using multivariable analysis, while comparison between group A and non-A recipients was performed after propensity score matching. RESULTS: Among 925 LT recipients, 406 were blood group A, 94 group B, 380 group O, and 45 group AB. On multivariable analysis, group A was associated with tumor recurrence (hazard ratio [HR] = 1.574 [95% confidence interval; 95% CI = 1.034-2.394] P = 0.034). After propensity score matching, 1- and 5-y recurrence rates were 7.4% and 20.1% in group A recipients versus 3.3% and 13.2% in non-A recipients (HR = 1.66 [95% CI = 1.12-2.45], P = 0.011). One and 5-y recurrence-free survivals were 85.2% and 66.8% in group A recipients versus 88.5% and 71.3% in non-A recipients (HR = 1.38 [95% CI = 1.01-1.90], P = 0.045). Among recipients within Milan criteria (n = 604), 1- and 5-y recurrence rates were 5.8% and 12.7% in group A recipients versus 3.1% and 12.2% in non-A recipients (HR = 1.197 [95% CI = 0.721-1.987], P = 0.485). Among recipients outside Milan criteria (n = 182), 1- and 5-y recurrence rates were 12.1% and 43.8% in group A recipients versus 3.9% and 15.6% in non-A recipients (HR = 3.175 [95% CI = 1.526-6.608], P = 0.002). CONCLUSIONS: ABO blood system influences the oncological outcome of recipients undergoing LT for HCC. Its incorporation in the prognostication model of LT for HCC may allow improving the management of LT candidates.

Hypothermic Oxygenated Perfusion Versus Normothermic Regional Perfusion in Liver Transplantation From Controlled Donation After Circulatory Death: First International Comparative Study.

OBJECTIVE: To compare HOPE and NRP in liver transplantation from cDCD. SUMMARY OF BACKGROUND DATA: Liver transplantation after cDCD is associated with higher rates of graft loss. Dynamic preservation strategies such as NRP and HOPE may offer safer use of cDCD grafts. METHODS: Retrospective comparative cohort study assessing outcomes after cDCD liver transplantation in 1 Swiss (HOPE) and 6 French (NRP) centers. The primary endpoint was 1-year tumor-death censored graft and patient survival. RESULTS: A total of 132 and 93 liver grafts were transplanted after NRP and HOPE, respectively. NRP grafts were procured from younger donors (50 vs 61 years, P < 0.001), with shorter functional donor warm ischemia (22 vs 31 minutes, P < 0.001) and a lower overall predicted risk for graft loss (UK-DCD-risk score 6 vs 9 points, P < 0.001). One-year tumor-death censored graft and patient survival was 93% versus 86% (P = 0.125) and 95% versus 93% (P = 0.482) after NRP and HOPE, respectively. No differences in non-anastomotic biliary strictures, primary nonfunction and hepatic artery thrombosis were observed in the total cohort and in 32 vs. 32 propensity score-matched recipients CONCLUSION:: NRP and HOPE in cDCD achieved similar post-transplant recipient and graft survival rates exceeding 85% and comparable to the benchmark values observed in standard DBD liver transplantation. Grafts in the HOPE cohort were procured from older donors and had longer warm ischemia times, and consequently achieved higher utilization rates. Therefore, randomized controlled trials with intention-to-treat analysis are needed to further compare both preservation strategies, especially for high-risk donor-recipient combinations.

What are the Particularities of Splenic Surgery in Cirrhotic Patients?

The aim of this work was to review the entire literature on splenic surgery in cirrhotic patients in order to best define the surgical indications and their management specifics. A review of the international literature published between January 1995 and August 2015 was thus carried out.

Major hepatectomy decreased tumor growth in an experimental model of bilobar liver metastasis.

BACKGROUND/PURPOSE: Two-stage hepatectomy (TSH), is associated with a risk of drop-out due to tumoral progression following portal vein occlusion (PVO). We explored the impact of majorhepatectomy on tumor growth by objective radiological measures comparing to PVO and minor hepatectomy, using a model of bilobar colorectal liver metastasis (CLM). METHODS: CLM were induced in 48 BDIX rats by injection of DHDK12-cells. 7 days after cells injection, animals were distributed into 4 groups of equal number (n = 12): portal vein ligation (PVL), sham laparotomy (sham), minor (30%Phx) and major (70%Phx) hepatectomy. MR imaging was used for in vivo analysis of tumor implantation, growth and volumes. RESULTS: At POD10, tumour volumes were homogeneously distributed among the 4 groups. Lower TV were significantly observed after 70%Phx comparing to PVL at POD17 (0.63 ± 0.14cm3 vs 0.9 ± 0.16cm3, p = 0.008) and to the 3 others groups at POD24: 1.78 ± 0.38cm3 vs 3.2 ± 0.62cm3 (PVL, p = 0.019), 2.41 ± 0.74cm3 (Sham, p = 0.024) and 2.32 ± 0.59cm3 (30%PHx, p = 0.019). CONCLUSION: We confirmed in a reproducible model that contrary to PVO, a major hepatectomy decreases the growth of CLM in the remnant liver. This result leads to questioning the usual TSH and justifies exploring alternative strategies. The "major hepatectomy first-approach" should be an option to be evaluated.

Comparison of Tissue and Blood Concentrations of Oxaliplatin Administrated by Different Modalities of Intraperitoneal Chemotherapy.

BACKGROUND: Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a new technology for delivering intraperitoneal chemotherapy. It is generally assumed that with PIPAC, the ratio of peritoneal to systemic drug concentration is superior to liquid hyperthermic intraperitoneal chemotherapy (HIPEC). To date, no direct comparative data are available supporting such an assumption. MATERIALS AND METHODS: Twelve 65-day-old pigs were randomly separated into three groups of four pigs each, all of which received intraperitoneal chemotherapy using the following administration methods: PIPAC with oxaliplatin 92 mg in 150 ml dextrose 5% (Group 1); PIPAC with electrostatic aerosol precipitation (ePIPAC; Group 2); or laparoscopic HIPEC (L-HIPEC) with oxaliplatin 400 mg in 4 L dextrose 5% at 42 °C (Group 3). Serial blood and peritoneal tissue concentrations of oxaliplatin were determined by spectrometry. RESULTS: In all three groups, the maximum concentration of oxaliplatin in blood was detected 50-60 min after onset of the chemotherapy experiments, with no significant differences among the three groups (p = 0.7994). Blood oxaliplatin concentrations (0-30 min) were significantly higher in the L-HIPEC group compared with the ePIPAC group (p < 0.05). No difference was found for the overall systemic oxaliplatin absorption (area under the curve). Overall concentrations in the peritoneum were not different among the three groups (p = 0.4725), but were significantly higher in the visceral peritoneum in the PIPAC group (p = 0.0242). CONCLUSIONS: Blood and tissue concentrations were comparable between all groups; however, depending on the intraperitoneal area examined and the time points of drug delivery, the concentrations differed significantly between the three groups.

Only Surgical Treatment to Be Considered for Adhesive Small Bowel Obstruction: A New Paradigm.

BACKGROUND: Adhesive small bowel obstruction (SBO) represents a heavy burden in healthcare systems worldwide and is associated with significant morbidity and mortality. Although conservative treatment alone can lead to SBO resolution in most cases, its optimal duration is still a matter of debate. The aim of this study was to analyze different SBO evolution patterns in order to further determine when to switch to surgical treatment. STUDY DESIGN: All patients who were admitted for adhesive SBO between 2011 and 2016 were reviewed. Patients who had immediate surgery (IS), a successful medical treatment (SMT), and a failed medical treatment (FMT) were compared in terms of overall morbidity, mortality, and SBO recurrence. RESULTS: Overall 154 patients were identified, including 23 (14.9%) in IS, 27 (17.5%) in FMT, and 104 (67.6%) in SMT groups. In terms of comorbidities, patients were similar in all groups. Overall morbidity rates were highest in IS and FMT groups (30% and 33%, respectively, vs. 4% in the SMT group, p < 0.001) whereas mortality rate was highest in the FMT group (22% vs. 0% and 0% in IS and SMT groups, respectively, p < 0.001). SBO recurrence rate was highest in the SMT group (22% vs. 4% and 7% in IS and FMT groups, respectively, p = 0.042). CONCLUSION: FMT seems to be associated with similar overall morbidity compared with IS but with increased postoperative mortality. Patient frailty seems to be worsened by prolonged inefficient medical treatment.

Transit time ultrasound perivascular flow probe technology is superior to MR imaging on hepatic blood flow measurement in a porcine model.

BACKGROUND: The hepatic hemodynamics is an essential parameter in surgical planning as well as in various disease processes. The transit time ultrasound (TTUS) perivascular flow probe technology is widely used in clinical practice to evaluate the hepatic inflow, yet invasive. The phase-contrast-MRI (PC-MRI) is not invasive and potentially applicable in assessing the hepatic blood flow. In the present study, we compared the hepatic inflow rates using the PC-MRI and the TTUS probe, and evaluated their predictive value of post-hepatectomy adverse events. METHODS: Eighteen large white pigs were anaesthetized for PC-MRI and approximately 75% hepatic resection was performed under a unified protocol. The blood flow was measured in the hepatic artery (Qha), the portal vein (Qpv), and the aorta above the celiac trunk (Qca) using PC-MRI, and was compared to the TTUS probe. The Bland-Altman method was conducted and a partial least squares regression (PLS) model was implemented. RESULTS: The mean Qpv measured in PC-MRI was 0.55 ±â€¯0.12 L/min, and in the TTUS probe was 0.74 ±â€¯0.17 L/min. Qca was 1.40 ±â€¯0.47 L/min in the PC-MRI and 2.00 ±â€¯0.60 L/min in the TTUS probe. Qha was 0.17 ±â€¯0.10 L/min in the PC-MRI, and 0.13 ±â€¯0.06 L/min in the TTUS probe. The Bland-Altman method revealed that the estimated bias of Qca in the PC-MRI was 32% (95% CI: -49% to 15%); Qha 17% (95% CI: -15% to 51%); and Qpv 40% (95% CI: -62% to 18%). The TTUS probe had a higher weight in predicting adverse outcomes after 75% resection compared to the PC-MRI (ß= 0.35 and 0.43 vs ß = 0.22 and 0.07, for tissue changes and premature death, respectively). CONCLUSIONS: There is a tendency of the PC-MRI to underestimate the flow measured by the TTUS probes. The TTUS probe measures are more predictive of relevant post-hepatectomy outcomes.

Recipient Selection for Optimal Utilization of Discarded Grafts in Liver Transplantation.

BACKGROUND: In France, liver grafts that have been refused by at least 5 teams are considered for rescue allocation (RA), with the choice of the recipient being at the team's discretion. Although this system permits the use of otherwise discarded grafts in a context of organ shortage, outcomes and potential benefits need to be assessed. METHODS: Between 2011 and 2015, outcomes of RA grafts (n = 33) were compared with SA grafts (n = 321) at a single French center. RESULTS: Liver grafts in the RA group were older (63 ± 17 years vs 54 ± 18 years, P = 0.007) and had a higher DRI (1.86 ± 0.45 vs 1.61 ± 0.47, P = 0.010). Recipients in this group had a lower Model for End-Stage Liver Disease score (14 ± 5 vs 22 ± 10, P < 0.001) and had mostly hepatocellular carcinoma (67.0% vs 40.4%, P = 0.010). The balance of risk score was significantly lower in the RA group (5.5 ± 2.9 vs 9.2 ± 5.5, P < 0.001). There were higher rates of early and delayed hepatic artery thrombosis (15.2% vs 3.1%, P = 0.001) and retransplantation (18.2% vs 4.7%, P = 0.002) in the RA group. Patient survival was not different between groups, but graft survival was impaired (95% vs 82% at 1 year and 94% vs 74% at 3 years, P = 0.001). CONCLUSION: Our results show that discarded liver grafts can be used provided that there is a strict recipient selection process, although hepatic artery thrombosis and retransplantation are more frequent. This strategy enables utilization of otherwise discarded grafts in the context of organ shortage.

Modulating Portal Hemodynamics With Vascular Ring Allows Efficient Regeneration After Partial Hepatectomy in a Porcine Model.

OBJECTIVE: To investigate safety and efficacy of temporary portal hemodynamics modulation with a novel percutaneously adjustable vascular ring (MID-AVR) onto a porcine model of 75% hepatectomy. BACKGROUND: Postoperative liver failure is a leading cause of mortality after major hepatectomy. Portal flow modulation is an increasingly accepted concept to prevent postoperative liver failure. Nonetheless, the current strategies have shortcomings. METHODS: Resection was performed under hemodynamic monitoring in 17 large, white pigs allocated into 2 groups. Eight pigs had ring around the portal vein for 3 days with the aim of reducing changes in hemodynamics due to hepatectomy. Analysis of hemodynamics, laboratory, and histopathological parameters was performed. RESULTS: Percutaneous inflation, deflation, and removal of the MID-AVR were safe. Two (25%) pigs in the MID-AVR group and 4 (45%) controls died before day 3 (P = NS). A moderate increase of portal flow rate per liver mass after resection was associated with better survival (P = 0.017). The portocaval pressure gradient was lower after hepatectomy in the MID-AVR group (P = 0.001). Postoperative serum bilirubin levels were lower in the MID-AVR group (P = 0.007 at day 5). In the MID-AVR group, the Ki67 index was significantly higher on day 3 (P = 0.043) and the architectural derangement was lower (P < 0.05). Morphometric quantification of the bile canaliculi revealed a significantly lower number of intersection branches (P < 0.05) and intersection nodes (P < 0.001) on day 7 compared with the preoperative specimen, in the control group. These differences were not found in the ring group. CONCLUSIONS: MID-AVR is safe for portal hemodynamics modulation. It might improve liver regeneration by protecting liver microarchitecture.

Management of the Open Abdomen after Liver Transplantation.

INTRODUCTION: The optimal management of the open abdomen (OA) after liver transplantation (LT) is unclear. The negative pressure wound therapy (NPWT) has been shown to be safe and can increase the chance for early fascial closure in trauma or septic patients. However, little data are available on the specific setting of LT. We aimed to report our experience of OA after LT, marked by the recent use of NPWT. METHODS: All patients with postponed wall closure after LT, from 2002 to 2014, in a single institution were included and retrospectively analyzed. Our management of OA after LT has shifted from skin-only closure (SOC) followed by abdominal wall reconstruction at a distance to the use of NPWT with early fascial closure. RESULTS: Of the 1559 LTs performed during the study period, immediate abdominal wall closure at the end of transplantation could not be achieved in 46 (2.9%) patients. Of them, SOC was performed in 22 (47.8%) patients, whereas vacuum-assisted closure (VAC) therapy was used in 24 (52.1%) patients. The comprehensive complication indexes (CCI) were similar [CCI: 66 (0-100) in the SOC group vs. 56 (0-100) in the VAC group; p = 0.55]. No evisceration or fistula occurred in both groups. One (4.2%) postoperative bleeding case was reported in the VAC group. Early fascial closure was achieved within a median of 5.5 days (1-12) for the 24 patients (100%) of the VAC group. In four of them, a biological mesh was necessary. Only nine patients (52.9%) of the survivors in the SOC group underwent abdominal reconstruction. CONCLUSION: The NPWT in patients with OA after LT enables early fascial closure with limited morbidity provided a specific attention is given to the risk of bleeding. These results support the use of NPWT as the first option in OA patients after LT.

Computerized tomography-based anatomic description of the porcine liver.

BACKGROUND: The knowledge of the anatomic features is imperative for successful modeling of the different surgical situations. This study aims to describe the anatomic features of the porcine using computerized tomography (CT) scan. METHODS: Thirty large, white, female pigs were included in this study. The CT image acquisition was performed in four-phase contrast study. Subsequently, analysis of the images was performed using syngo.via software (Siemens) to subtract mainly the hepatic artery and its branches. Analysis of the portal and hepatic veins division pattern was performed using the Myrian XP-Liver 1.14.1 software (Intrasense). RESULTS: The mean total liver volume was 915 ± 159 mL. The largest sector in the liver was the right medial one representing around 28 ± 5.7% of the total liver volume. Next in order is the right lateral sector constituting around 24 ± 5%. Its volume is very close to the volume of the left medial sector, which represents around 22 ± 4.7% of the total liver volume. The caudate lobe represents around 8 ± 2% of the total liver volume.The portal vein did not show distinct right and left divisions rather than consecutive branches that come off the main trunk. The hepatic artery frequently trifurcates into left trunk that gives off the right gastric artery and the artery to the left lateral sector, the middle hepatic artery that supplies both the right and the left medial sectors and the right hepatic artery trunk that divides to give anterior branch to the right lateral lobe, branch to the right medial lobe, and at least a branch to the caudate lobe. Frequently, there is a posterior branch that crosses behind the portal vein to the right lateral lobe. The suprahepatic veins join the inferior vena cava in three distinct openings. There are communications between the suprahepatic veins that drain the adjacent sectors. The vein from the right lateral and the right medial sectors drains into a common trunk. The vein from the left lateral and from the left medial sectors drains into a common trunk. A separate opening is usually encountered draining the right medial sector. The caudate lobe drains separately into inferior vena cava caudal to the other veins. CONCLUSIONS: Knowledge of the anatomic features of the porcine liver is crucial to the performance of a successful surgical procedure. We herein describe the CT-depicted anatomic features of the porcine liver.

Partial hepatectomy hemodynamics changes: Experimental data explained by closed-loop lumped modeling.

The liver function may be degraded after partial liver ablation surgery. Adverse liver hemodynamics have been shown to be associated to liver failure. The link between these hemodynamics changes and ablation size is however poorly understood. This article proposes to explain with a closed-loop lumped model the hemodynamics changes observed during twelve surgeries in pigs. The portal venous tree is modeled with a pressure-dependent variable resistor. The variables measured, before liver ablation, are used to tune the model parameters. Then, the liver partial ablation is simulated with the model and the simulated pressures and flows are compared with post-operative measurements. Fluid infusion and blood losses occur during the surgery. The closed-loop model presented accounts for these blood volume changes. Moreover, the impact of blood volume changes and the liver lobe mass estimations on the simulated variables is studied. The typical increase of portal pressure, increase of liver pressure loss, slight decrease of portal flow and major decrease in arterial flow are quantitatively captured by the model for a 75% hepatectomy. It appears that the 75% decrease in hepatic arterial flow can be explained by the resistance increase induced by the surgery, and that no hepatic arterial buffer response (HABR) mechanism is needed to account for this change. The different post-operative states, observed in experiments, are reproduced with the proposed model. Thus, an explanation for inter-subjects post-operative variability is proposed. The presented framework can easily be adapted to other species circulations and to different pathologies for clinical hepatic applications.

Simplified technique for 75% and 90% hepatic resection with hemodynamic monitoring in a large white swine model.

BACKGROUND: Accurate measuring of the hepatic hemodynamic parameters in humans is inconvenient. Swine has been a favorite surgical model for the study of liver conditions due to many similarities with human livers. However, pigs cannot tolerate pedicle clamping and to reduce bleeding during resection a simplified technique is required. The aim of this study is to present a simplified technique for different percentages of hepatic resection in a porcine model. METHODS: Twenty-two consecutive large white pigs were operated with 75% and 90% liver resection. Computarized tomography liver volumetry is performed before and after surgery. In both types of surgery, hemodynamic monitoring was performed using a specialized apparatus. RESULTS: Resections were performed in both groups successfully. The residual volume in the planned 75% was 235 ± 77 mL and 118 ± 119 mL in the planned 90% resection. For 75% resection, the portal flow was reduced after resection by 8.13 ± 28%, which might be part of systemic circulatory depression. However, the portal pressure increased by 20.1 ± 51%. The hepatic artery flow decreased by 63.86 ± 26.3% as well as the pressure by 5 ± 28%. The central venous pressure at the start of surgery was 3.34 ± 1.9 mm Hg and 2.8 ± 2.2 mm Hg at the end of surgery. The portacaval pressure gradient was 4.4 ± 2.9 mm Hg at the beginning of surgery and was 5.9 ± 2.8 mm Hg at the end of surgery. For 90% resection, the portal flow decreased by 33.6 ± 12.6% and the pressure increased by 104 ± 58%. The hepatic artery flow decreased by 88 ± 7%, and the pressure decreased by 5 ± 14.8%. The central venous pressure was 3.5 ± 1.7 mm Hg before resection and 3 ± 2.5 mm Hg after resection. The portacaval pressure gradient was 3.8 ± 1.1 mm Hg before resection and 8 ± 3.7 mm Hg after resection. The mean anesthesia time was 6.6 ± 1.05 h and 6.9 ± 0.5 h for 75% and 90% resection, respectively. The mean operative time was 4.6 ± 0.9 h and 5 ± 0.7 h for 75% and 90% resections, respectively. The mean time for hepatectomy was 1.23 ± 0.76 h and 2.4 ± 0.1 h for 75% and 90% resection, respectively. The mean time consumed in the measurements was 2.28 ± 1.4 h and 1.1 ± 0.3 h for 75% and 90% resections, respectively. The mean volume of aspirated fluid and blood in the 75% resection was 1062 ± 512 mL, while it was 1050 ± 354 mL in 90% resections. CONCLUSIONS: The hereby described technique is simple and easily applicable for major liver resection in a porcine model. Portal flow decreases after 90% resection more than in 75% due to the relative reduction of remnant hepatic mass. There was a larger increase in portal pressure following 90% compared to 75% resection. The hepatic artery flow decreases more in 90% than in 75% resections.