Search

Contemporary species distributions and geographic patterns of genetic structure largely reflect pre-historic events, often with subsequent alterations from human influences. The geographic genetic structure of a relatively common and widespread unionid species, Quadrula quadrula, was investigated to reconstruct its postglacial history. Hypotheses regarding colonization routes of Q. quadrula into the Great Lakes basin after the most recent glacial retreat were tested. Samples were collected from Q. quadrula at sites spanning hypothesized glacial refugia and postglacial expansion routes in the Mississippi River drainage, including the Ohio and Missouri rivers, and the Great Lakes. Broad-scale phylogeography and population structure were assessed by sequencing a fragment of the mitochondrial CO1 gene and genotyping eight microsatellites. Results of analyses showed marked differences among the Great Lakes, Mississippi River, and Ohio River drainages, and suggested colonization of the Great Lakes basin from a Mississippian source. Populations showed patterns of isolation by distance: geographic and genetic distances were significantly correlated among Great Lakes populations based on colonization through the Chicago–Illinois outlet, but not when following the Wabash–Maumee outlet. All evidence indicates that postglacial colonization of the Great Lakes basin occurred almost exclusively through the Chicago–Illinois outlet, with subsequent expansion into the lower Great Lakes. [ABSTRACT FROM AUTHOR]

Alterations to watercourses affect connectivity in aquatic systems and can influence dispersal of aquatic biota. Dams fragment populations and act as isolating barriers, but canals create connections between waterbodies that can be used as corridors for dispersal by opportunistic invaders. The Niagara Peninsula of Ontario, Canada, has a 200-y history of canal operation, resulting in major modification of the watercourses in the region. This modification allowed numerous invasive species to enter the upper Great Lakes (e.g., sea lamprey) and probably has facilitated dispersal in native species. The purpose of our study was to explore the effects of canal and dam construction on the genetic structure of Mapleleaf (Quadrula quadrula), a widespread and relatively common species in the central Great Lakes that has been found only recently in several western Lake Ontario harbors. Establishment of Q. quadrula in Lake Ontario may have been a recent event, facilitated by the Niagara Peninsula’s history of canal operation. We used analyses of microsatellite DNA genotypes to examine the effect of canals on the genetic structure of mussel populations. Structure analysis revealed a pattern of gene flow between lakes that cannot be explained by watercourse connections prior to the creation of the Welland Canal. Evidence suggestive of historical bottlenecks at some Lake Ontario sites may indicate that these populations became established after canal creation. After considering genetic structure, hydrogeography and isolation-by-distance (IBD) analysis, the first iteration of the canal (1829–1833) is most supported as the configuration that facilitated colonization. However, weak IBD signals across canal models may signify continued gene flow across configurations. Our study demonstrates the connective effect of canals on freshwater mussel populations and has the potential to improve conservation strategies for this and other unionid species at risk. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented about a case of a highly aggressive prostatic carcinoma with widespread rectal invasion in a patient who underwent a total pelvic exenteration to address the symptoms.

Background: Thoracoabdominal normothermic regional perfusion (TA-NRP) has emerged as a powerful technique for optimizing organ procurement from donation after circulatory death donors. Despite its rapid adoption, standardized guidelines for TA-NRP implementation are lacking, prompting the need for consensus recommendations to ensure safe and effective utilization of this technique., Methods: A working group composed of members from The American Society of Transplant Surgeons, The International Society of Heart and Lung Transplantation, The Society of Thoracic Surgeons, and The American Association for Thoracic Surgery was convened to develop technical guidelines for TA-NRP. The group systematically reviewed existing literature, consensus statements, and expert opinions to identify key areas requiring standardization, including predonation evaluation, intraoperative management, postdonation procedures, and future research directions., Results: The working group formulated recommendations encompassing donor evaluation and selection criteria, premortem testing and therapeutic interventions, communication protocols, and procedural guidelines for TA-NRP implementation. These recommendations aim to facilitate coordination among transplant teams, minimize variability in practice, and promote transparency and accountability throughout the TA-NRP process., Conclusions: The consensus guidelines presented herein serve as a comprehensive framework for the successful and ethical implementation of TA-NRP programs in organ procurement from donation after circulatory death donors. By providing standardized recommendations and addressing areas of uncertainty, these guidelines aim to enhance the quality, safety, and efficiency of TA-NRP procedures, ultimately contributing to improved outcomes for transplant recipients., Competing Interests: The authors declare no funding or conflicts of interest., (Copyright © 2024 The Transplantation Society and The Society of Thoracic Surgeons. Published by Wolters Kluwer Health, Inc on behalf of The Transplantation Society and by Elsevier, Inc on behalf of The Society of Thoracic Surgeons. All rights are reserved, including those for text and data mining, AI training, and similar technologies. Either citation may be used when citing this article.)

Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Since 2019, the annual transplantation rate of hearts donated following circulatory death (DCD) has increased significantly in the United States. The 2 major heart procurement techniques following circulatory death are direct procurement and perfusion (DPP) and normothermic regional perfusion (NRP). Post-transplant survival for heart recipients has not been compared between these 2 techniques., Methods: This observational study uses data on adult heart transplants from donors after circulatory death from January 1, 2019 to December 31, 2021 in the Scientific Registry of Transplant Recipients. We identified comparable transplant cases across procurement types using propensity-score matching and measured the association between procurement technique and 1-year post-transplant survival using Kaplan-Meier and Cox proportional hazards model stratefied by matching pairs., Results: Among 318 DCD heart transplants, 216 (68%) were procured via DPP, and 102 (32%) via NRP. Among 22 transplant centers that accepted circulatory-death donors, 3 used NRP exclusively, and 5 used both procurement techniques. After propensity-score matching on recipient and donor factors, there was no significant difference in 1-year post-transplant survival (93.1% for NRP vs 91.1% for DPP, p = 0.79) between procurement techniques., Conclusions: NRP and DPP procurements are associated with similar 1-year post-transplant survival. If NRP is ethically permissible and improves outcomes for abdominal organs, it should be the preferred procurement technique for DCD hearts., (Copyright © 2024 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Donation after circulatory death (DCD) could account for the largest expansion of the donor allograft pool in the contemporary era. However, the organ yield and associated costs of normothermic regional perfusion (NRP) compared to super-rapid recovery (SRR) with ex-situ normothermic machine perfusion, remain unreported. The Organ Procurement and Transplantation Network (December 2019 to June 2023) was analyzed to determine the number of organs recovered per donor. A cost analysis was performed based on our institution's experience since 2022. Of 43 502 donors, 30 646 (70%) were donors after brain death (DBD), 12 536 (29%) DCD-SRR and 320 (0.7%) DCD-NRP. The mean number of organs recovered was 3.70 for DBD, 3.71 for DCD-NRP (P < .001), and 2.45 for DCD-SRR (P < .001). Following risk adjustment, DCD-NRP (adjusted odds ratio 1.34, confidence interval 1.04-1.75) and DCD-SRR (adjusted odds ratio 2.11, confidence interval 2.01-2.21; reference: DBD) remained associated with greater odds of allograft nonuse. Including incomplete and completed procurement runs, the total average cost of DCD-NRP was $9463.22 per donor. By conservative estimates, we found that approximately 31 donor allografts could be procured using DCD-NRP for the cost equivalent of 1 allograft procured via DCD-SRR with ex-situ normothermic machine perfusion. In conclusion, DCD-SRR procurements were associated with the lowest organ yield compared to other procurement methods. To facilitate broader adoption of DCD procurement, a comprehensive understanding of the trade-offs inherent in each technique is imperative., Competing Interests: Declaration of competing interest The authors of this manuscript have conflicts of interest to disclose as described by the American Journal of Transplantation. John Gutowski and Jordan Hoffman are individual shareholders in TransMedics. Jordan Hoffman is a member of the Donor Alliance Advisory Board and recipient of the ISHLT/O.H. “Bud” Frazier Grant in MCS Translational Research sponsored by Medtronic (ended 2022). Joseph Cleveland received payment from Abbott Medical for serving as the chair of the CEC for the ARiES HM3 trial. Elizabeth Pomfret is the President of the American Society of Transplant Surgeons. Syed Shahyan Bakhtiyar, Tiffany Maksimuk, Sarah Park, Michael Cain, Jessica Rove, T. Brett Reece, James Pomposelli, Yanik Bababekov, Trevor Nydam, and Jesse Schold have no financial disclosures or conflicts of interest to report., (Copyright © 2024 American Society of Transplantation & American Society of Transplant Surgeons. Published by Elsevier Inc. All rights reserved.)

Pulmonary arterial stiffness (PAS) is a pathologic hallmark of all types of pulmonary hypertension (PH). Cardiac MRI (CMR), a gold-standard imaging modality for the evaluation of pulmonary flow, biventricular morphology and function has been historically reserved for the longitudinal clinical follow-up, PH phenotyping purposes, right ventricular evaluation, and research purposes. Over the last two decades, numerous indices combining invasive catheterization and non-invasive CMR have been utilized to phenotype the character and severity of PAS in different types of PH and to assess its clinically prognostic potential with encouraging results. Many recent studies have demonstrated a strong role of CMR derived PAS markers in predicting long-term clinical outcomes and improving currently gold standard risk assessment provided by the REVEAL calculator. With the utilization of a machine learning strategies, strong diagnostic and prognostic performance of CMR reported in multicenter studies, and ability to detect PH at early stages, the non-invasive assessment of PAS is on verge of routine clinical utilization. In this review, we focus on appraising important CMR studies interrogating PAS over the last 20 years, describing the benefits and limitations of different PAS indices, and their pathophysiologic relevance to pulmonary vascular remodeling. We also discuss the role of CMR and PAS in clinical surveillance and phenotyping of PH, and the long-term future goal to utilize PAS as a biomarker to aid with more targeted therapeutic management., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

Objective: Donation after circulatory death (DCD) procurement and transplantation after thoracoabdominal normothermic regional perfusion (TA-NRP) remains a novel technique to improve cardiac and hepatic allograft preservation but may be complicated by lung allograft pulmonary edema. We present a single-center series on early implementation of a lung-protective protocol with strategies to mitigate posttransplant pulmonary edema in DCD lung allografts after TA-NRP procurement., Methods: Data from all lung transplantations performed using a TA-NRP procurement strategy from October 2022 to April 2023 are presented. Donor management consisted of key factors to reduce lung allograft pulmonary edema: aggressive predonation and early posttransplant diuresis, complete venous drainage at TA-NRP initiation, and early pulmonary artery venting upon initiation of systemic perfusion. Donor and recipient characteristics, procurement characteristics such as TA-NRP intervals, and 30-day postoperative outcomes were assessed., Results: During the study period, 8 lung transplants were performed utilizing TA-NRP procurement from DCD donors. Donor ages ranged from 16 to 39 years and extubation time to declaration of death ranged from 10 to 90 minutes. Time from declaration to TA-NRP initiation was 7 to 17 minutes with TA-NRP perfusion times of 49 to 111 minutes. Median left and right allograft warm ischemia times were 55.5 minutes (interquartile range, 46.5-67.5 minutes) and 41.0 minutes (interquartile range, 39.0-53.0 minutes, respectively, with 2 recipients supported with cardiopulmonary bypass or venoarterial extracorporeal membrane oxygenation during implantation. No postoperative extracorporeal membrane oxygenation was required. There were no pulmonary-related deaths; however, 1 patient died from complications of severe necrotizing pancreatitis with a normal functioning allograft. All patients were extubated within 24 hours. Index intensive care unit length of stay ranged from 3 to 11 days with a hospital length of stay of 13 to 37 days., Conclusions: Despite concern regarding quality of DCD lung allografts recovered using the TA-NRP technique, we report initial success using this procurement method. Implementation of strategies to mitigate pulmonary edema can result in acceptable outcomes following lung transplantation. Demonstration of short- and long-term safety and efficacy of this technique will become increasingly important as the use of TA-NRP for thoracic and abdominal allografts in DCD donors expands., Competing Interests: The authors reported no conflicts of interest. The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest., (© 2023 The Author(s).)

The relationship between social determinants of health and outcomes after heart transplantation has not been examined. The social vulnerability index (SVI) uses United States census data to determine the social vulnerability of every census tract based on 15 factors. This retrospective study seeks to examine the impact of SVI on outcomes after heart transplantation. Adult heart recipients who received a graft between 2012 and 2021 were stratified into SVI percentiles of <75% and SVI of ≥75%. The primary endpoint was survival. The median SVI was 48% (interquartile range: 30%-67%) among 23 700 recipients. One-year survival was similar between groups (91.4 vs 90.7%, log-rank P = .169); however, 5-year survival was lower among individuals living in vulnerable communities (74.8% vs 80.0%, P < .001). This finding persisted despite risk adjustment for other factors associated with mortality (survival time ratio 0.819, 95% confidence interval: 0.755-0.890, P < .001). The incidences of 5-year hospital readmission (81.4% vs 75.4%, P < .001) and graft rejection (40.3% vs 35.7%, P = .004) were higher among individuals living in vulnerable communities. Individuals living in vulnerable communities may be at increased risk of mortality after heart transplantation. These findings suggest there is an opportunity to focus on these recipients undergoing heart transplantation to improve survival., Competing Interests: Declaration of interests The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Alejandro Suarez-Pierre reports financial support was provided by American Association for Thoracic Surgery., (Copyright © 2023 American Society of Transplantation & American Society of Transplant Surgeons. Published by Elsevier Inc. All rights reserved.)

Increasing the number of available hearts for transplantation is the best strategy to decrease waitlist mortality. This study examines organ procurement organizations (OPOs) and their role in the transplantation network to determine whether variability in performance exists across them. Adult deceased donors who met the criteria for brain death between 2010 and 2020 (inclusive) in the United States were examined. A regression model was fitted and internally validated using donor characteristics available at the time of organ recovery to predict the likelihood of heart transplantation. Subsequently, an expected heart yield was calculated for each donor using this model. Observed-to-expected (O/E) heart yield ratios for each OPO were calculated by dividing the number of hearts recovered for transplantation by the expected number of recoveries. There were 58 OPOs active during the study period, and on average, OPO activity grew over time. The mean O/E ratio among OPOs was 0.98 (standard deviation ± 0.18). Twenty-one OPOs consistently performed below the expected level (95% confidence intervals < 1.0) and generated a deficit of 1,088 expected transplantations during the study period. The proportion of hearts that were recovered for transplantation varied significantly by OPO categories: low tier 31.8%, mid tier 35.6%, and high tier 36.2% (p < 0.01), even as the expected yield was similar across tiers (p = 0.69). OPO performance accounts for 28% of the variability in successfully transplanting a heart after accounting for the role of referring hospitals, donor families, and transplantation centers. In conclusion, there is significant variability in volume and heart yield from brain-dead donors across OPOs., Competing Interests: Disclosure: The authors have no relevant conflicts of interest. This content is the responsibility of the authors alone and does not necessarily reflect the view or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the US Government., (Copyright © ASAIO 2023.)

Mortality on the liver waitlist remains unacceptably high. Donation after circulatory determination of death (DCD) donors are considered marginal but are a potentially underutilized resource. Thoraco-abdominal normothermic perfusion (TA-NRP) in DCD donors might result in higher quality livers and offset waitlist mortality. We retrospectively reviewed outcomes of the first 13 livers transplanted from TA-NRP donors in the US. Nine centers transplanted livers from eight organ procurement organizations. Median donor age was 25 years; median agonal phase was 13 minutes. Median recipient age was 60 years; median lab MELD score was 21. Three patients (23%) met early allograft dysfunction (EAD) criteria. Three received simultaneous liver-kidney transplants; neither had EAD nor delayed renal allograft function. One recipient died 186 days post-transplant from sepsis but had normal presepsis liver function. One patient developed a biliary anastomotic stricture, managed endoscopically; no recipient developed clinical evidence of ischemic cholangiopathy (IC). Twelve of 13 (92%) patients are alive with good liver function at 439 days median follow-up; one patient has extrahepatic recurrent HCC. TA-NRP DCD livers in these recipients all functioned well, particularly with respect to IC, and provide a valuable option to decrease deaths on the waiting list., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Given the shortage of suitable donor hearts for cardiac transplantation and the growing interest in donation after circulatory death (DCD), our institution recently began procuring cardiac allografts from DCD donors., Methods: Between October 2020 and March 2021, 15 patients with heart failure underwent cardiac transplantation using DCD allografts. Allografts were procured using a modified extracorporeal membrane oxygenation circuit for thoracic normothermic regional perfusion (TA-NRP) and were subsequently transported using cold static storage. Data collection and analysis were performed with institutional review board approval., Results: The mean age of the DCD donors was 23 ± 7 years and average time on TA-NRP was 56 ± 8 minutes. Total ischemic time was 183 ± 31 minutes and distance from transplant center was 373 ± 203 nautical miles. Recipient age was 55 ± 14 years, with 8 (55.3%) recipients on durable left ventricular assist device support. Post-transplant, 6 (40%) recipients experienced mild left ventricle primary graft dysfunction (PGD-LV), 3 (20%) recipients experienced moderate PGD-LV, and no recipients experienced severe PGD-LV. Postoperative transthoracic echocardiogram demonstrated left ventricular ejection fraction >55% in all recipients. One recipient (6.6%) developed International Society for Heart and Lung Transplantation 2R acute cellular rejection on first biopsy. At last follow-up, all 15 recipients were alive past 30-days., Conclusions: Cardiac DCD provides an opportunity to increase the availability of donor hearts for transplantation. Utilizing TA-NRP with cold static storage, we have extended the cold ischemic time of DCD allografts to almost 3 hours, allowing for inter-hospital organ transport., (Copyright © 2021 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)