Surgery (Austin & Northern Health) - Research Publications
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ItemThe Hidden Epidemic: The Prevalence and Impact of Concurrent Liver Diseases in Patients Undergoing Liver Transplantation in Australia and New Zealand(LIPPINCOTT WILLIAMS & WILKINS, 2022-08)UNLABELLED: Prevalence of concurrent liver diseases among liver transplant recipients and impact on posttransplant outcomes are unknown. METHODS: This retrospective study included adult liver transplants between January 1' 1985' and December 31' 2019' from the Australian and New Zealand Liver and Intestinal Transplant Registry. Up to 4 liver disease causes were recorded for each transplant; concurrent liver diseases were defined as >1 liver disease indication for transplantation, excluding hepatocellular carcinoma. Impact on posttransplant survival was determined using Cox regression. RESULTS: A total of 840 (15%) of 5101 adult liver transplant recipients had concurrent liver diseases. Recipients with concurrent liver diseases were more likely male (78% versus 64%) and older (mean age 52 versus 50 y). A higher proportion of liver transplants for hepatitis B (12% versus 6%), hepatitis C (33% versus 20%), alcohol liver disease (23% versus 13%), and metabolic-associated fatty liver disease (11% versus 8%, all P < 0.001) were identified when all indications were included than with primary diagnosis only. The number and proportion of liver transplants performed for concurrent liver diseases have increased from 8 (6%) during Era 1 (1985-1989) to 302 (20%) during Era 7 (2015-2019; P < 0.001). Concurrent liver diseases were not associated with increased posttransplant mortality (adjusted hazard ratio, 0.98, 95% confidence interval, 0.84-1.14). CONCLUSIONS: Concurrent liver diseases are increasing among adult liver transplant recipients in Australia and New Zealand; however, they do not appear to impact posttransplant survival. Reporting all liver disease causes in the transplant registry reports provides more accurate estimates of liver disease burden.
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ItemLung-resident memory B cells established after pulmonary influenza infection display distinct transcriptional and phenotypic profiles(AMER ASSOC ADVANCEMENT SCIENCE, 2022-01)Recent studies have established that memory B cells, largely thought to be circulatory in the blood, can take up long-term residency in inflamed tissues, analogous to widely described tissue-resident T cells. The dynamics of recruitment and retention of memory B cells to tissues and their immunological purpose remains unclear. Here, we characterized tissue-resident memory B cells (BRM) that are stably maintained in the lungs of mice after pulmonary influenza infection. Influenza-specific BRM were localized within inducible bronchus-associated lymphoid tissues (iBALTs) and displayed transcriptional signatures distinct from classical memory B cells in the blood or spleen while showing partial overlap with memory B cells in lung-draining lymph nodes. We identified lung-resident markers, including elevated expression of CXCR3, CCR6, and CD69, on hemagglutinin (HA)- and nucleoprotein (NP)-specific lung BRM. We found that CCR6 facilitates increased recruitment and/or retention of BRM in lungs and differentiation into antibody-secreting cells upon recall. Although expression of CXCR3 and CCR6 was comparable in total and influenza-specific memory B cells isolated across tissues of human donors, CD69 expression was higher in memory B cells from lung and draining lymph nodes of human organ donors relative to splenic and PBMC-derived populations, indicating that mechanisms underpinning BRM localization may be evolutionarily conserved. Last, we demonstrate that human memory B cells in lungs are transcriptionally distinct to populations in lung-draining lymph nodes or PBMCs. These data suggest that BRM may constitute a discrete component of B cell immunity, positioned at the lung mucosa for rapid humoral response against respiratory viral infections.
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ItemExpansion of Liver Transplantation Criteria for Hepatocellular Carcinoma from Milan to UCSF in Australia and New Zealand and Justification for Metroticket 2.0.(MDPI AG, 2022-06-03)Background: Expansion in liver transplantation (LT) criteria for HCC from Milan to UCSF has not adversely impacted overall survival, prompting further expansion towards Metroticket 2.0 (MT2). In this study, we compared patient survival post-transplant before and after 2007 and long-term outcomes for LT within Milan versus UCSF criteria (to determine the true benefit of the expansion of criteria) and retrospectively validated the MT2 criteria. Methods: Retrospective analysis of ANZLITR (including all patients transplanted for HCC since July 1997). The entire cohort was divided based on criteria used at the time of listing, namely, Milan era (1997−2006) and the UCSF era (2007−July 2015). Results: The overall 5- and 10-year cumulative survival rates for the entire cohort of 691 patients were 78% and 69%, respectively. Patients transplanted in UCSF era had significantly higher 5- and 10-year survival rates than in the Milan era (80% vs. 73% and 72% vs. 65%, respectively; p = 0.016). In the UCSF era, the 5-year survival rate for patients transplanted within Milan criteria was significantly better than those transplanted outside Milan but within UCSF criteria (83% vs. 73%; p < 0.024). Patients transplanted within the MT2 criteria had a significantly better 5- and 10-year survival rate as compared to those outside the criteria (81% vs. 64% and 73% vs. 50%, respectively; p = 0.001). Conclusion: Overall survival following LT for HCC has significantly improved over time despite expanding criteria from Milan to UCSF. Patients fulfilling the MT2 criteria have a survival comparable to the UCSF cohort. Thus, expansion of criteria to MT2 is justifiable.
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ItemOutcomes for children after second liver transplantations are similar to those after first transplantations: a binational registry analysis(WILEY, 2020-11)Objective To assess long term graft and patient survival after donor liver retransplantation in children in Australia and New Zealand during 1986–2017; to determine the factors that influence survival. Design Retrospective cohort analysis (registry data). Setting, participants Australia and New Zealand Liver Transplant Registry data for all liver retransplantations in children (under 18 years of age), 1986–2017, in all four paediatric and six adult liver transplantation centres in the two countries. Main outcome measures Graft and patient survival at one, 5, 10 and 15 years. Results 142 liver retransplantations were undertaken in children (59 during 1986–2000, 83 during 2001–2017). Kaplan–Meier survival analysis indicated that survival was significantly greater during 2001–2017 than 1986–2000 (P < 0.001). During 2001–2017, graft survival one year after retransplantation was 84%, at 5 years 75%, at 10 years 70%, and at 15 years 54%; patient survival was 89% at one year, 87% at 5 years, 87% at 10 years, and 71% at 15 years. Median time between transplantations was 0.2 years (IQR, 0.03–1.4 years) during 1986–2000, and 1.8 years (IQR, 0.1–6.8 years) during 2001–2017 (P = 0.002). The proportion of graft failures that involved split grafts was larger during 2001–2017 (35 of 83, 42%) than 1986–2000 (10 of 59, 17%). Graft type, cause of graft failure, and number of transplants did not influence survival following retransplantation. Conclusion Survival for children following retransplantation is excellent. Graft survival is similar for split and whole grafts. Children on the liver waiting list requiring retransplantation should have the same access to donor grafts as children requiring a first transplant.
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ItemAdaptive immunity to human coronaviruses is widespread but low in magnitude(WILEY, 2021)OBJECTIVES: Endemic human coronaviruses (hCoVs) circulate worldwide but cause minimal mortality. Although seroconversion to hCoV is near ubiquitous during childhood, little is known about hCoV-specific T-cell memory in adults. METHODS: We quantified CD4 T-cell and antibody responses to hCoV spike antigens in 42 SARS-CoV-2-uninfected individuals. Antigen-specific memory T cells and circulating T follicular helper (cTFH) cells were identified using an activation-induced marker assay and characterised for memory phenotype and chemokine receptor expression. RESULTS: T-cell responses were widespread within conventional memory and cTFH compartments but did not correlate with IgG titres. SARS-CoV-2 cross-reactive T cells were observed in 48% of participants and correlated with HKU1 memory. hCoV-specific T cells exhibited a CCR6+ central memory phenotype in the blood, but were enriched for frequency and CXCR3 expression in human lung-draining lymph nodes. CONCLUSION: Overall, hCoV-specific humoral and cellular memory are independently maintained, with a shared phenotype existing among coronavirus-specific CD4 T cells. This understanding of endemic coronavirus immunity provides insight into the homeostatic maintenance of immune responses that are likely to be critical components of protection against SARS-CoV-2.
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ItemTurning the Tide on Hepatitis C Virus-Related Liver Transplantation: The Return on Investment in Hepatitis C Virus Treatment in Australia and New Zealand(WILEY, 2022-02)Introduction of universal access to direct-acting antiviral (DAA) therapy for hepatitis C virus (HCV) in Australia and New Zealand on March 1st , 2016, has had a major impact on the number of people with chronic HCV infection, but the impact on liver transplantation rates is unknown. We conducted a retrospective registry study including all adult liver transplantations from the Australia and New Zealand Liver and Intestinal Liver Transplant Registry (ANZLITR) data set. Interrupted time series analysis determined the impact of DAAs in 2016 on the number of HCV liver transplantations per year. Cox regression analysis was used to determine the impact of DAAs on post-liver transplantation survival. Between January 1, 1990, and December 31, 2019 5318 adult liver transplantations were performed, and 29% (1531) were for HCV infection. Prior to the introduction of DAAs, there was a mean increase of 3.5 adult liver transplantations performed for HCV per annum, but between 2016 and 2019 there was a mean decrease of 7.9 adult liver transplantations per annum (P < 0.001). Similarly, the proportion of liver transplantations performed for HCV increased from 9% (1990) to 33% in 2016 and then fell to 23% in 2019 (P < 0.001). The number and proportion of patients with HCV added to the liver transplantation waiting list also fell in 2016 (P < 0.001) when compared with other indications. The introduction of DAAs was associated with a 31% reduction in death after liver transplantation, adjusted for age at transplant and hepatocellular carcinoma (HCC; hazard ratio [HR], 0.69; 95% confidence interval [CI], 0.48-0.99; P = 0.047). The number of adult liver transplantations performed for HCV-related liver cirrhosis and HCC has reduced since the introduction of universal access to DAAs in 2016 in Australia and New Zealand.
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ItemThe use of organ donor blood in liver transplantation(WILEY, 2021-09)BACKGROUND: Blood removed from organs during deceased donor organ procurement is routinely discarded but is a potential resource for donor-specific transfusion (DST) in subsequent liver transplantation (LT). This study retrospectively analyses the impact of DST on intraoperative bank blood product usage, long-term graft, and patient survival, as well as frequency of rejection post-LT. METHODS: A total of 992 adult LT performed from 1993 to 2018 in a single quaternary center were included. Intraoperative blood product usage, patient, and graft survival, as well as acute and chronic rejection were assessed in patients who received blood retrieved from the organ donor, the "donor blood" (DB) group (n = 437) and patients who did not, the "no donor blood" (NDB) group (n = 555). RESULTS: Processing of DB ensured safe levels of potassium, magnesium, and insulin. There were fewer units of bank red blood cells transfusion required in the DB group compared to NDB group (2 vs. 4 units, P = .01). Graft survival was significantly superior in the DB group (10-year survival 75% vs. 69%, respectively, P = .04) but DST was not an independent predictor of graft survival. There was no significant difference in patient survival or rejection between the groups. There was no difference in treated, biopsy-proven rejection between the two groups. CONCLUSIONS: This is the first large-cohort study assessing long-term outcomes of intraoperative DST in LT. The collection of organ donor blood and subsequent use in LT recipients appeared feasible with appropriate quality checks ensuring safety. DST resulted in a reduction in the use of packed red blood cells. There was no difference in the rate of rejection or graft or patient survival.
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ItemReduction in post-operative pancreatic fistula with polyethylene glycol and recombinant human albumin sealant following stapled distal pancreatectomy(WILEY, 2021-11)BACKGROUND: Postoperative pancreatic fistula (POPF) remains a significant cause of morbidity in patients undergoing distal pancreatectomy (DP). The use of polyethylene glycol (PEG) and recombinant human albumin sealant gel applied to the transected pancreatic margin in DP may reduce POPF rates and was assessed. METHODS: A retrospective single centre cohort study of patient undergoing DP at an Australian high volume tertiary institution between January 2015 and January 2021. Rates of POPF in patients undergoing stapled pancreatic transection with PEG sealant were compared to other methods. RESULTS: A total of 54 cases were identified for analysis, with 16 undergoing stapled DP combined with staple line application of PEG (PEG group). Most patients in the control group had stapled DP 92% (35 of 38), with 47% (18 of 38) combined with a reinforcing buttress, with or without the use other glue types. Overall, 28 of 54 (52%) developed a POPF, with a significantly lower rate in the PEG group (3 of 16 vs. 25 of 38 in the Control group; p = 0.003). Clinically significant Grade B/C POPF was lower in the PEG group (0 of 16 vs. 9 of 28 in the Control group; p = 0.045), and patients in the PEG group had a shorter median (range) length of hospital stay (6 [4-14] days vs. 10 [6-41] days p = 0.04). CONCLUSION: Stapled DP with the application of PEG and recombinant human albumin sealant to the transection line appears to be associated with a lower rate of clinically significant POPF.
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ItemElevated levels of circulating mitochondrial DNA predict early allograft dysfunction in patients following liver transplantation(WILEY, 2021-12)BACKGROUND AND AIM: The role of circulating mitochondrial DNA (cmtDNA) in transplantation remains to be elucidated. cmtDNA may be released into the circulation as a consequence of liver injury; yet recent work also suggests a causative role for cmtDNA leading to hepatocellular injury. We hypothesized that elevated cmtDNA would be associated with adverse events after liver transplantation (LT) and conducted an observational cohort study. METHODS: Twenty-one patients were enrolled prospectively prior to LT. RESULTS: Postoperative complications were observed in 47.6% (n = 10). Seven patients (33.3%) had early allograft dysfunction (EAD), and six patients (28.5%) experienced acute cellular rejection within 6 months of LT. cmtDNA levels were significantly elevated in all recipients after LT compared with healthy controls and preoperative samples (1 361 937 copies/mL [IQR 586 781-3 399 687] after LT; 545 531 copies/mL [IQR 238 562-1 381 015] before LT; and 194 562 copies/mL [IQR 182 359-231 515] in healthy controls) and returned to normal levels by 5 days after transplantation. cmtDNA levels were particularly elevated in those who developed EAD in the early postoperative period (P < 0.001). In all patients, there was initially a strong overall positive correlation between cmtDNA and plasma hepatocellular enzyme levels (P < 0.05). However, the patients with EAD demonstrated a second peak in cmtDNA at postoperative day 7, which did not correlate with liver function tests. CONCLUSIONS: The early release of plasma cmtDNA is strongly associated with hepatocellular damage; however, the late surge in cmtDNA in patients with EAD appeared to be independent of hepatocellular injury as measured by conventional tests.