Common hepatic artery lymph node metastasis in pancreatic ductal adenocarcinoma: an analysis of actual survival.

BACKGROUND: The common hepatic artery lymph node (CHALN) represents a second-echelon node for tumors in the head of the pancreas. Although early studies suggested survival was comparable between the CHALN and remote metastasis in pancreatic ductal adenocarcinoma (PDAC), whether the lymph node is associated with adverse survival remains equivocal. Here, we examined a prospective cohort of patients calculating actual survival to better understand implications of this specific lymph node metastasis. METHODS: We studied 215 patients with pancreatic head PDAC, who underwent pancreaticoduodenectomies at a single institution between 2010 and 2017, wherein the CHALNs were excised. We performed actual and actuarial overall survival and disease-free survival (DFS) analyses, with subsequent univariate and multivariate analyses in node-positive patients. RESULTS: Of this cohort, 7.3% of patients had involvement of the CHALN, and all of them had metastatic spread to first-echelon nodes. Actual median survival of patients with no lymph node involvement was 49 months. In patients with any nodal involvement, the survival was no different when comparing the lymph node positive and negative (13 and 20 months, respectively). Univariate and multivariate analyses likewise attached no significance to the lymph node metastasis, while demonstrating worse survival with positive margin status and poorly differentiated histology. Our DFS analyses yielded similar results. CONCLUSION: We found no difference in actual survival in node-positive patients regardless of the CHALN involvement and recommended against its assessment in prognosticating survival or guiding surgical treatment.

Chimeric Antigen Receptor T Cell with an Inducible Caspase 9 Suicide Gene Eradicates Uveal Melanoma Liver Metastases via B7-H3 Targeting

PURPOSE: Uveal melanoma (UM) is the most common intraocular malignant tumor. Despite successful treatment of the primary tumor, about 50% of patients will recur with systemic disease for which there are no effective treatment strategies. Here we investigated the preclinical efficacy of a chimeric antigen receptor (CAR) T cell-based immunotherapy targeting B7-H3. EXPERIMENTAL DESIGN: B7-H3 expression on primary and metastatic human UM samples and cell lines was assessed by RNA sequencing, flow cytometry, and immunohistochemistry. Antitumor activity of CAR T cells targeting B7-H3 was tested in vitro with UM cell lines, metastatic UM patient-derived organotypic tumor spheroids (PDOTS), and in immunodeficient and humanized murine models. RESULTS: B7-H3 is expressed at high levels on >95% UM tumor cells in vitro and in vivo. We generated a B7-H3 CAR with an inducible caspase-9 (iCas9) suicide gene controlled by the chemical inducer of dimerization AP1903, which effectively kills UM cells in vitro and eradicates UM liver metastases in murine models. Delivery of iCas9.B7-H3 CAR T cells in experimental models of UM liver metastases demonstrates a durable anti-tumor response, even upon tumor re-challenge or in the presence of a significant metastatic disease burden. We demonstrate effective iCas9.B7-H3 CAR T cell elimination in vitro and in vivo in response to AP1903. Our studies demonstrate more effective tumor suppression with iCas9.B7-H3 CAR T cells as compared to a B7-H3-targeted humanized monoclonal antibody. CONCLUSIONS: These studies support a phase I clinical trial with iCas9.B7-H3 CAR T cells to treat patients with metastatic UM.

Interplay between B7-H3 and HLA class I in the clinical course of pancreatic ductal adenocarcinoma.

Human leukocyte antigen (HLA) class I defects are associated with cancer progression. However, their prognostic significance is controversial and may be modulated by immune checkpoints. Here, we investigated whether the checkpoint B7-H3 modulates the relationship between HLA class I and pancreatic ductal adenocarcinoma (PDAC) prognosis. PDAC tumors were analyzed for the expression of B7-H3, HLA class I, HLA class II molecules, and for the presence of tumor-infiltrating immune cells. We observed defective HLA class I and HLA class II expressions in 75% and 59% of PDAC samples, respectively. HLA class I and B7-H3 expression were positively related at mRNA and protein level, potentially because of shared regulation by RELA, a sub-unit of NF-kB. High B7-H3 expression and low CD8+ T cell density were indicators of poor survival, while HLA class I was not. Defective HLA class I expression was associated with unfavorable survival only in patients with low B7-H3 expression. Favorable survival was observed only when HLA class I expression was high and B7-H3 expression low. Our results provide the rationale for targeting B7-H3 in patients with PDAC tumors displaying high HLA class I levels.

Implications of High Tumor Burden on Chimeric Antigen Receptor T-Cell Immunotherapy: A Review.

Importance: Chimeric antigen receptor (CAR) T-cell therapy has redefined the therapeutic landscape of several hematologic malignant tumors. Despite its clinical efficacy, many patients with cancer experience nonresponse to CAR T-cell treatment, disease relapse within months, or severe adverse events. Furthermore, CAR T-cell therapy has demonstrated minimal to no clinical efficacy in the treatment of solid tumors in clinical trials. Observations: A complex interplay between high tumor burden and the systemic and local tumor microenvironment on clinical outcomes of CAR T-cell therapy is emerging from preclinical and clinical data. The hallmarks of advanced cancers-namely, inflammation and immune dysregulation-sustain cancer progression. They negatively affect the production, expansion, antitumor activity, and persistence of CAR T-cell products. Understanding of CAR T-cell therapy, mechanisms underlying its failure, and adverse events under conditions of high tumor burden is critical for realizing the full potential of this novel treatment approach. Conclusions and Relevance: This review focuses on linking the efficacy and safety of CAR T-cell therapy with tumor burden. Its limitations relative to high tumor burden, systemic inflammation, and immune dysregulation are discussed. Emerging clinical approaches to overcome these obstacles and more effectively incorporate this therapeutic strategy into the treatment paradigm of patients with solid malignant tumors are also described.

CSPG4 CAR-redirected Cytokine Induced Killer lymphocytes (CIK) as effective cellular immunotherapy for HLA class I defective melanoma.

BACKGROUND: Even acknowledging the game-changing results achieved in the treatment of metastatic melanoma with the use of immune checkpoint inhibitors (ICI), a large proportion of patients (40-60%) still fail to respond or relapse due to the development of resistance. Alterations in the expression of Human Leukocyte Antigen class I (HLA-I) molecules are considered to play a major role in clinical resistance to ICI. Cellular immunotherapy with HLA-independent CAR-redirected lymphocytes is a promising alternative in this challenging setting and dedicated translational models are needed. METHODS: In this study, we propose an HLA-independent therapeutic strategy with Cytokine Induced Killer lymphocytes (CIK) genetically engineered with a Chimeric Antigen Receptor (CAR) targeting the tumor antigen CSPG4 as effector mechanism. We investigated the preclinical antitumor activity of CSPG4-CAR.CIK in vitro and in a xenograft murine model focusing on patient-derived melanoma cell lines (Mel) with defective expression of HLA-I molecules. RESULTS: We successfully generated CSPG4-CAR.CIK from patients with metastatic melanoma and reported their intense activity in vitro against a panel of CSPG4-expressing patient-derived Mel. The melanoma killing activity was intense, even at very low effector to target ratios, and not influenced by the expression level (high, low, defective) of HLA-I molecules on target cells. Furthermore, CAR.CIK conditioned medium was capable of upregulating the expression of HLA-I molecules on melanoma cells. A comparable immunomodulatory effect was replicated by treatment of Mel cells with exogenous IFN-γ and IFN-α. The antimelanoma activity of CSPG4-CAR.CIK was successfully confirmed in vivo, obtaining a significant tumor growth inhibition of an HLA-defective Mel xenograft in immunodeficient mice. CONCLUSIONS: In this study we reported the intense preclinical activity of CSPG4-CAR.CIK against melanoma, including those with low or defective HLA-I expression. Our findings support CSPG4 as a valuable CAR target in melanoma and provide translational rationale for clinical studies exploring CAR-CIK cellular immunotherapies within the challenging setting of patients not responsive or relapsing to immune checkpoint inhibitors.

Stressed target cancer cells drive nongenetic reprogramming of CAR T cells and solid tumor microenvironment.

The poor efficacy of chimeric antigen receptor T-cell therapy (CAR T) for solid tumors is due to insufficient CAR T cell tumor infiltration, in vivo expansion, persistence, and effector function, as well as exhaustion, intrinsic target antigen heterogeneity or antigen loss of target cancer cells, and immunosuppressive tumor microenvironment (TME). Here we describe a broadly applicable nongenetic approach that simultaneously addresses the multiple challenges of CAR T as a therapy for solid tumors. The approach reprograms CAR T cells by exposing them to stressed target cancer cells which have been exposed to the cell stress inducer disulfiram (DSF) and copper (Cu)(DSF/Cu) plus ionizing irradiation (IR). The reprogrammed CAR T cells acquire early memory-like characteristics, potent cytotoxicity, enhanced in vivo expansion, persistence, and decreased exhaustion. Tumors stressed by DSF/Cu and IR also reprogram and reverse the immunosuppressive TME in humanized mice. The reprogrammed CAR T cells, derived from peripheral blood mononuclear cells of healthy donors or metastatic female breast cancer patients, induce robust, sustained memory and curative anti-solid tumor responses in multiple xenograft mouse models, establishing proof of concept for empowering CAR T by stressing tumor as a promising therapy for solid tumors.

Long-Term Outcomes of Tuberous Sclerosis Complex-Associated Non-functional Pancreatic Neuroendocrine Tumors: Should We Be More Conservative?

BACKGROUND: Hereditary syndromes such as tuberous sclerosis complex (TSC) account for 10% of pancreatic neuroendocrine tumors (PNETs). Surgical intervention is the current standard of care for sporadic PNETs (spPNETs) that are >2 cm in size. We compared the long-term outcomes of resected TSC-PNETs with patients with spPNETs. METHODS: We conducted a retrospective review of perioperative data and outcomes of TSC-PNETs compared with spPNETs. Inclusion criteria involved selecting patients whose tumors were no larger than 5.1 cm, the maximum size observed in the TSC-PNET group. RESULTS: Of the 347 patients resected for PNETs, 14 were TSC-PNETs and 241 were non-functional spPNETs. The median age for the whole cohort was 56 years (interquartile range [IQR] 21.0) and 47% were female. The median follow-up was 103.8 months (95% confidence interval [CI] 89.2-118.6). Specifically, 14 patients with TSC-PNETs and 194 patients with spPNETs were included. Compared with spPNETs, patients with TSC-PNETs were operated on at a younger age (24.0 vs. 57.5 years; p < 0.001), were more frequently multifocal (28.5% vs. 0.0%; p < 0.001), were more likely to undergo minimally invasive operations (78.6% vs. 24.3%; p < 0.001), and had more R1 resections (28.6% vs. 5.7%; p = 0.006). Local and distant tumor recurrence was only observed in the spPNET group. The 5-year mortality rates for the spPNET and TSC-PNET groups were 6.2% and 0.0%, respectively. No PNET-related deaths were observed among TSC-PNETs. CONCLUSION: None of the TSC-PNET patients recurred after a median follow-up of 78.0 months. The risk-benefit of aggressive pancreatic operations in TSC-PNET patients is still unclear and our findings suggest a conservative approach should be considered.

B7-H3-targeted CAR T cell activity is enhanced by radiotherapy in solid cancers.

Adoptive cell therapy utilizing T cells genetically modified to express a chimeric antigen receptor (CAR) has demonstrated promising clinical results in hematological malignancies. However, solid cancers have not seen a similar success due to multiple obstacles. Investigating these escape mechanisms and designing strategies to counteract such limitations is crucial and timely. Growing evidence in the literature supports the hypothesis that radiotherapy has the potential to enhance the susceptibility of solid tumors to CAR T cell therapy, by overcoming mechanisms of resistance. Radiation treatment can increase the susceptibility of different types of solid cancers (TNBC, HNSCC, PDAC) to B7-H3 CAR T cell-mediated eradication. Multiple mechanisms, including reduced cancer cell proliferation, upregulation of the targeted antigen, modulation of apoptotic molecules may contribute to this signal. The information in the literature and the results we describesupport the ability of radiotherapy to improve the efficacy of CAR T cell therapy in solid tumors.

Association between artificial nutrition in brain dead donors and early allograft function in liver transplant recipients: an observational study.

BACKGROUND: The role of nutrition in donor after brain deaths (DBDs) has yet to be adequately discussed. The primary aim of this study was to investigate whether the nutritional intake in the 48 h before organ retrieval may play a role on the graft functional recovery assessed with Model for Early Allograft Function (MEAF) Score. METHODS: Single-center retrospective study evaluating all liver transplants performed at the University Hospital of Udine from January 2010 to August 2020. Patients receiving grafts from DBD donors fed with artificial enteral nutrition in the 48 h prior to organ procurement (EN-group) or who did not (No-EN-group). Caloric debt was calculated using the difference between the calculated caloric needs and the effective calories delivered through enteral nutrition. RESULTS: Livers from EN-group presented a lower mean MEAF score compared to the no-EN-group: 3.39 ± 1.46 versus 4.15 ± 1.51, respectively (p = .04). A positive correlation between caloric debt and the MEAF score was found within the overall population (r = .227, p = .043) as well as in EN-group (r = .306, p = .049). CONCLUSIONS: Donor's nutritional intake in the final 48 h before organ procurement correlates with MEAF score, and nutrition probably plays a positive role on the functional recovery of the graft. Large future randomized controlled trials are needed to confirm this preliminary results.

A rare case of duplication of the descending colon in a pregnant woman: case report and literature review.

INTRODUCTION: Gastrointestinal duplications are uncommon congenital abnormalities that can occur anywhere throughout the intestinal tract. The small bowel is more interested than the large one. Duplications are schematically classified as spherical and tubular, respectively representing 80% and 20% of cases, with different relationships and communications with the native intestinal wall. Although typically diagnosed during infancy and early childhood, tubular colonic sub-type stays frequently hidden for several years until a complication occurs. CASE PRESENTATION: we report the case of a T-shaped tubular duplication in a 20-year-old woman at the 30th week of gestation, who underwent an urgent exploratory laparotomy for intestinal occlusion, treated with the resection of the aberrant large bowel. The patient was notable for a long history of constipation and chronic pain. Diagnostic possibilities were limited by the on-going pregnancy. CONCLUSION: Intestinal duplications are uncommon malformations, and, of these, the T-shaped subtype of the colon is among the rarest ones. In the adulthood, diagnosis is usually established in the operating room during urgent or even emergency surgery performed for abdominal complications. A duplication of the descending colon is extremely rare, and this is, to our knowledge, the only article describing a case found in advanced state of pregnancy.

Is the indocyanine green clearance test useful in viral acute liver failure? Maybe!

N/A.

Current practice with grafts with multiple renal arteries in kidney transplantation: role of the methylene blue in the lower pole.

Kidneys with multiple renal arteries (MRAs) from different patches, may provide to the surgeon additional technical difficulties that make kidney transplants very challenging. MRAs have been largely debated over the years whether to be anastomosed or not due to the disappointing outcomes when it comes to inappropriate ligation or anastomosis.  Some authors empirically reassure that smaller branches can be safely ligated and dissected without intraoperative and postoperative complications or compromising the functional recovery of the graft. Literature is poor about the possible differences in the management of superior and inferior polar arteries. Inferior polar arteries represent a topic of great interest as they may also supply the proximal ureter. The aim of this article is to merge the current knowledge about the management of inferior polar arteries and to highlight if there is any role of the methylene blue dye (MB) in the study of the ureteral vascularization in kidney transplantation. MB can be considered a safe and simple tool of vascular perfusion assessment in kidney transplantation. By injecting the dye-solution into the inferior MRA hidden ureteral branches can be unmasked and guide the surgeon to preserve important vessels. In view of their fundamental role in the vascularization of the ureter, the lower polar arteries of the graft, should be invariably studied by MB. It provides an objective, simple and fast tool for the evaluation of the ureteral vascularization when injected through the inferior MRA of the graft.

Association between preoperative diastolic dysfunction and early allograft dysfunction after orthotopic liver transplantation: An observational study.

OBJECTIVES: To investigate the association between the grade of diastolic dysfunction (DD) and the occurrence of early allograft dysfunction (EAD) in liver transplant patients following the new 2016 American Society of Echocardiography/European Association of Cardiovascular Imaging (ASE/EACVI) guidelines. METHODS: From January 2015 to December 2019, we retrospectively analyzed 83 patients who underwent orthotopic liver transplantation (OLTx) and their susceptibility to develop EAD according to the grade of preoperative DD. EAD was defined according to the criteria proposed by Olfhoff et al.; DD was defined with four parameters: E/A, e/e', Left Atrium volume, and Tricuspid Regurgitation velocity. RESULTS: According to the ASE/EACVI guidelines grade II DD was detected in 20 patients (24.1%) undergoing OLTx. A statistically significant association was found between grade II DD and the occurrence of EAD (p-value < 0.003). The Kaplan-Meier analysis failed to find any significant difference between the survival probability, nevertheless at the end of a 90-day follow-up period, mortality showed a different trend in classes with more severe diastolic dysfunction. CONCLUSION: According to the ASE/EACVI guidelines from 2016, patients with grade II DD seem to have a higher propensity to develop early allograft dysfunction EAD after OLTx. Our study advises a need for an urgent prospective multicenter study to elucidate the long-term outcomes of liver transplants patients with diastolic dysfunction.

Assessment of hepatic steatosis based on needle biopsy images from deceased donor livers.

BACKGROUND: Assessment of hepatic steatosis (HS) before transplantation requires the pathologist to read a graft biopsy. A simple method based on the evaluation of images from tissue samples with a smartphone could expedite and facilitate the liver selection. This study aims to assess the degree of HS by analysing photographic images from liver needle biopsy samples. METHODS: Thirty-three biopsy-images were acquired with a smartphone. Image processing was carried out using ImageJ: background subtraction, conversion to HSB colour space, segmentation of the biopsy area, and evaluation of statistical features of Hue, Saturation, Brightness, Red, Green, and Blue channels on the biopsy area. After feature extraction, correlations were made with gold standard HS percentage assessed at two levels (frozen-section vs glass-slide). Sensitivity, specificity, and accuracy were calculated for each feature. RESULTS: Correlations were found for H, S, R. The sensitivity, specificity, and accuracy of the final classifier based on the K* algorithm were 94%, 92%, 94%. LIMITATIONS: Accuracy assessment was performed considering macrovesicular steatosis on specimens with mostly < 30% HS. CONCLUSIONS: The steatosis assessment based on needle biopsy images, proved to be an effective and promising method. Deep learning approaches could also be experimented with a larger set of images.

Association between indocyanine green clearance test and ischemic type biliary lesions within one year after orthotopic liver transplantation / Asociación entre la prueba de clearance verde de indocianina y las lesiones biliares de tipo isquémico dentro de un año después del trasplante ortotópico de hígado

Background: Ischemic type biliary lesions (ITBLs), a particular subset of non-anastomotic biliary strictures (NAS), are characterized by intra and extrahepatic strictures that occur in the absence of either hepatic artery thrombosis or stenosis. When they occur within the first year after liver transplantation their development is mostly related to ischemia–reperfusion injury (IRI). The indocyanine green plasma disappearance rate (ICG-PDR) might be able to predict the probability of IRI-induced graft damage after liver transplantation. Objective: Our aim was to evaluate the association between ICG-PDR and the occurrence of ITBLs. Secondly, we searched for evidence of IRI in patients presenting ITBLs. Methods: This retrospective single-center observational study assessed a cohort of 60 liver transplant patients. Each patient underwent ICG-PDR on the 1st postoperative day. ITBLs were identified by means of either cholangiography or magnetic resonance imaging evidence of a deformity and narrowing of the biliary tree in the absence of hepatic artery thrombosis/stenosis. Results: ITBLs were discovered in 10 patients out of 60 liver recipients (16.67%) within one year after transplantation. A low ICG-PDR value was found to be a significant predictive factor for ITBL development, with an OR of 0.87 and a 95% CI of 0.77–0.97. Liver biopsies were performed in 56 patients presenting unexplained abnormal liver function test results. A statistically significant association was found between the development of ITBLs and anatomopathological evidence of IRI. Limitations: Retrospective, single-center study. Conclusions: The findings from this study show a relationship between low ICG-PDR values on first post-operative-day and the occurrence of ITBLs within 1 year after transplantation.(AU)

Antecedentes: Las lesiones biliares de tipo isquémico (ITBL) representan un subconjunto de estenosis biliares no anastomóticas, caracterizadas por estenosis intra y extrahepáticas, que ocurren en ausencia de trombosis o estenosis de la arteria hepática. Cuando ocurren dentro del primer año después del trasplante de hígado, están relacionadas principalmente con la lesión por isquemia-reperfusión (IRI). La tasa de desaparición del plasma con verde de indocianina (ICG-PDR) podría estimar el daño del injerto inducido por IRI después de un trasplante. Objetivo: Nuestro objetivo es evaluar la asociación entre ICG-PDR y la aparición de ITBL. También investigamos la evidencia de IRI entre los pacientes que presentaron ITBL. Métodos: Estudio observacional, retrospectivo, unicéntrico, realizado en una cohorte de 60 receptores trasplantados con determinacion del ICG-PDR el primer día posoperatorio. Las ITBL se definieron mediante colangiografía o evidencia por resonancia magnética de deformidad del árbol biliar en ausencia de trombosis/estenosis de la arteria hepática. Resultados: De 60 receptores, se descubrieron ITBL en 10 pacientes (16,67%) en el primer año. El valor bajo de ICG-PDR es un factor predictivo significativo para ITBL, con OR=0,87 y un IC (95%)=0,77-0,97. Se analizaron 56 biopsias hepáticas para la presencia de IRI, si los receptores presentaban una prueba de función hepática anormal inexplicable, encontrando asociación significativa entre ITBL y evidencia anatomopatológica de IRI. Limitaciones: Estudio retrospectivo, unicéntrico.(AU)

The Challenging Management of an Intracardiac Thrombus in a Liver Transplant Patient at the Reperfusion Phase: A Case Report and Brief Literature Review.

The exact origin of intracardiac thrombi formation during orthotopic liver transplant remains unknown. The altered balance between hypercoagulability, hypocoagulation, and endothelial dysfunction associated with end-stage liver disease is thought to play a pivotal role. Venous stasis, vascular clamping, and reperfusion could also contribute to clot formation. The incidence of intracardiac thrombi formation stands at 4.2%, associated with a mortality rate of 45.5%, and to date, no consensus exists regarding the best way to treat this complication. Intraoperative transesophageal echocardiography is the only effective method for diagnosing intracardiac thrombi formation early, while point-of-care coagulation testing could guide the coagulation management potentially improving patient outcomes.

Association between the donor to recipient ICG-PDR variation rate and the functional recovery of the graft after orthotopic liver transplantation: A case series.

BACKGROUND: Despite current advances in liver transplant surgery, post-operative early allograft dysfunction still complicates the patient prognosis and graft survival. The transition from the donor has not been yet fully understood, and no study quantifies if and how the liver function changes through its transfer to the recipient. The indocyanine green dye plasma disappearance rate (ICG-PDR) is a simple validated tool of liver function assessment. The variation rate between the donor and recipient ICG-PDR still needs to be investigated. MATERIALS AND METHODS: Single-center retrospective study. ICG-PDR determinations were performed before graft retrieval (T1) and 24 hours after transplant (T2). The ICG-PDR relative variation rate between T1 and T2 was calculated to assess the graft function and suffering/recovering. Matched data were compared with the MEAF model of graft dysfunction. OBJECTIVE: To investigate whether the variation rate between the donor ICG-PDR value and the recipient ICG-PDR measurement on first postoperative day (POD1) can be associated with the MEAF score. RESULTS: 36 ICG-PDR measurements between 18 donors and 18 graft recipients were performed. The mean donor ICG-PDR was 22.64 (SD 6.35), and the mean receiver's ICG-PDR on 1st POD was 17.68 (SD 6.60), with a mean MEAF value of 4.51 (SD 1.23). Pearson's test stressed a good, linear inverse correlation between the ICG-PDR relative variation and the MEAF values, correlation coefficient -0.580 (p = 0.012). CONCLUSION: The direct correlation between the donor to recipient ICG-PDR variation rate and MEAF was found. Measurements at T1 and T2 showed an up- or downtrend of the graft performance that reflect the MEAF values.

Association between indocyanine green clearance test and ischemic type biliary lesions within one year after orthotopic liver transplantation.

BACKGROUND: Ischemic type biliary lesions (ITBLs), a particular subset of non-anastomotic biliary strictures (NAS), are characterized by intra and extrahepatic strictures that occur in the absence of either hepatic artery thrombosis or stenosis. When they occur within the first year after liver transplantation their development is mostly related to ischemia-reperfusion injury (IRI). The indocyanine green plasma disappearance rate (ICG-PDR) might be able to predict the probability of IRI-induced graft damage after liver transplantation. OBJECTIVE: Our aim was to evaluate the association between ICG-PDR and the occurrence of ITBLs. Secondly, we searched for evidence of IRI in patients presenting ITBLs. METHODS: This retrospective single-center observational study assessed a cohort of 60 liver transplant patients. Each patient underwent ICG-PDR on the 1st postoperative day. ITBLs were identified by means of either cholangiography or magnetic resonance imaging evidence of a deformity and narrowing of the biliary tree in the absence of hepatic artery thrombosis/stenosis. RESULTS: ITBLs were discovered in 10 patients out of 60 liver recipients (16.67%) within one year after transplantation. A low ICG-PDR value was found to be a significant predictive factor for ITBL development, with an OR of 0.87 and a 95% CI of 0.77-0.97. Liver biopsies were performed in 56 patients presenting unexplained abnormal liver function test results. A statistically significant association was found between the development of ITBLs and anatomopathological evidence of IRI. LIMITATIONS: Retrospective, single-center study. CONCLUSIONS: The findings from this study show a relationship between low ICG-PDR values on first post-operative-day and the occurrence of ITBLs within 1 year after transplantation.