Antony Moheb Attia

All Publications

• Effect of recipient age on prioritisation for liver transplantation in the UK: a population-based modelling study. The lancet. Healthy longevity Attia, A., Webb, J., Connor, K., Johnston, C. J., Williams, M., Gordon-Walker, T., Rowe, I. A., Harrison, E. M., Stutchfield, B. M. 2024; 5 (5): e346-e355

  Abstract

  Following the introduction of an algorithm aiming to maximise life-years gained from liver transplantation in the UK (the transplant benefit score [TBS]), donor livers were redirected from younger to older patients, mortality rate equalised across the age range and short-term waiting list mortality reduced. Understanding age-related prioritisation has been challenging, especially for younger patients and clinicians allocating non-TBS-directed livers. We aimed to assess age-related prioritisation within the TBS algorithm by modelling liver transplantation prioritisation based on data from a UK transplant unit and comparing these data with other regions.In this population-based modelling study, serum parameters and age at liver transplantation assessment of patients attending the Scottish Liver Transplant Unit, Edinburgh, UK, between December, 2002, and November, 2023, were combined with representative synthetic data to model TBS survival predictions, which were compared according to age group (25-49 years vs ≥60 years), chronic liver disease severity, and disease cause. Models for end-stage liver disease (UKELD [UK], MELD [Eurotransplant region], and MELD 3.0 [USA]) were used as validated comparators of liver disease severity.Of 2093 patients with chronic liver disease, 1808 (86%) had complete datasets and liver disease parameters consistent with eligibility for the liver transplant waiting list in the UK (UKELD ≥49). Disease severity as assessed by UKELD, MELD, and MELD 3.0 did not differ by age (median UKELD scores of 56 for patients aged ≥60 years vs 56 for patients aged 25-49 years; MELD scores of 16 vs 16; and MELD 3.0 scores of 18 vs 18). TBS increased with advancing age (R=0·45, p<0·0001). TBS predicted that transplantation in patients aged 60 years or older would provide a two-fold greater net benefit at 5 years than in patients aged 25-49 years (median TBS 1317 [IQR 1116-1436] in older patients vs 706 [411-1095] in younger patients; p<0·0001). Older patients were predicted to have shorter survival without transplantation than younger patients (263 days [IQR 144-473] in older patients vs 861 days [448-1164] in younger patients; p<0·0001) but similar survival after transplantation (1599 days [1563-1628] vs 1573 days [1525-1614]; p<0·0001). Older patients could reach a TBS for which a liver offer was likely below minimum criteria for transplantation (UKELD <49), whereas many younger patients were required to have high-urgent disease (UKELD >60). US and Eurotransplant programmes did not prioritise according to age.The UK liver allocation algorithm prioritises older patients for transplantation by predicting that advancing age increases the benefit from liver transplantation. Restricted follow-up and biases in waiting list data might limit the accuracy of these benefit predictions. Measures beyond overall waiting list mortality are required to fully capture the benefits of liver transplantation.None.

  View details for DOI 10.1016/S2666-7568(24)00044-8

  View details for PubMedID 38705152

• Implausible algorithm output in UK liver transplantation allocation scheme: importance of transparency. Lancet (London, England) Attia, A., Rowe, I. A., Harrison, E. M., Gordon-Walker, T., Stutchfield, B. M. 2023; 401 (10380): 911-912

  View details for DOI 10.1016/S0140-6736(23)00114-9

  View details for PubMedID 36870362

• Highly Sensitized Pediatric Kidney Candidates Have Reduced Access to Kidney Transplant in the United States. American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons Nakayama, T., Ahn, D. J., Attia, A., Bozhilov, K. K., Kirchner, V. A., Sasaki, K., Busque, S., Melcher, M. L., Pham, T. A. 2026

  Abstract

  Kidney transplantation is prioritized for children in the United States, yet equity for highly sensitized pediatric candidates remains uncertain. Using Organ Procurement and Transplantation Network data, we examined kidney-only candidates aged 0-17 years listed between December 4, 2014 and December 31, 2024 who were ever activated, comparing the Kidney Allocation System (KAS; Era 1) and the 2021 circle-based revision (KAS250; Era 2). Candidates were stratified by calculated panel-reactive antibody (cPRA) at first activation (0-20%, 21-79%, 80-99%, 100%). The primary outcome was 3-year cumulative incidence of deceased-donor kidney transplant (DDKT) in competing-risk analysis. Among 7,215 activated pediatric candidates, highly sensitized candidates accepted organs from greater distances. In both eras, candidates with cPRA 80-99% (Era 1: SHR 0.46, 95%CI 0.36-0.59; Era 2: SHR 0.53, 95%CI 0.42-0.67) and cPRA 100% (Era 1: SHR 0.28, 95%CI 0.16-0.48; Era 2: SHR 0.28, 95%CI 0.18-0.43) had persistently reduced access to DDKT (all p<0.001). While non-sensitized candidates had higher DDKT rates than adults, those with cPRA 80-99% or 100% had similar rates to adults. Findings suggest that pediatric prioritization does not fully extend to highly sensitized children, supporting the need for broader sharing.

  View details for DOI 10.1016/j.ajt.2026.05.008

  View details for PubMedID 42142590

• Current status of split liver transplantation using machine perfusion in the United States. HPB : the official journal of the International Hepato Pancreato Biliary Association Nakayama, T., Ito, R., Attia, A., Ahn, D. J., Ichida, H., Shiraki, S., Sasaki, K. 2026

  View details for DOI 10.1016/j.hpb.2026.04.465

  View details for PubMedID 42156276

• Out-of-Sequence or Out of Options? Rethinking Liver Allocation in a Crisis of Confidence. American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons Attia, A., Sasaki, K., Kwong, A. J. 2026

  View details for DOI 10.1016/j.ajt.2026.02.029

  View details for PubMedID 41771356

• Status Exceptions and Misalignment of Medical Urgency in U.S. Pediatric Heart Transplantation. Journal of the American College of Cardiology Ahn, D. J., Attia, A., Nakayama, T., Narang, N., Daly, K., Khush, K. K., Parker, W. F., Sasaki, K. 2026

  Abstract

  Pediatric heart transplant candidates experience high waitlist mortality, in part because of limited availability of appropriate donor hearts. Transplant physicians can request status exceptions to increase priority for candidates, but this practice may contribute to overcrowding of high-priority statuses. In 2021, the National Heart Review Board (NHRB) was established to standardize exception review, but its impact remains unknown.The goal of this study was to determine whether exceptions are granted to children at high risk of death on the waitlist and the impact of the NHRB on outcomes.Using Organ Procurement and Transplantation Network data, we identified all pediatric heart transplant candidates listed March 2016 through March 2025. We estimated the association between status exceptions and waitlist mortality using mixed-effects Cox proportional hazards models and compared concordance indices for the current system vs a hypothetical system without exceptions.Among 6,026 candidates, 745 (12.4%) died or deteriorated and 1,668 (27.7%) received exceptions. Exception recipients had a significantly lower waitlist mortality risk than standard criteria patients (HR: 0.41; 95% CI: 0.31-0.55; P < 0.001) and the NHRB's impact on this association was nonsignificant (P = 0.62). We observed significant heterogeneity in waitlist mortality within status 1A, with exception recipients having the highest survival. When modeling waitlist mortality, the concordance index improved from 0.694 (95% CI: 0.682-0.706) with exceptions to 0.713 (95% CI: 0.700-0.724) without exceptions (P < 0.001).Pediatric heart transplant candidates granted status exceptions have significantly lower medical urgency than those meeting standard criteria. Implementation of a national review board did not result in improved alignment between waitlist mortality and listing status.

  View details for DOI 10.1016/j.jacc.2026.01.052

  View details for PubMedID 41778948

• Potential Double Counting in Meta-Analysis of Combined Heart-liver Transplantation. Transplantation Nakayama, T., Attia, A., Ahn, D. J., Sasaki, K. 2026

  View details for DOI 10.1097/TP.0000000000005642

  View details for PubMedID 41604423

• Current status of minimally invasive liver transplantation: a narrative review ANNALS OF LAPAROSCOPIC AND ENDOSCOPIC SURGERY Nakayama, T., Attia, A., Ahn, D. J., Sasaki, K., Margonis, G. 2026; 11

  View details for DOI 10.21037/ales-2025-1-52

  View details for Web of Science ID 001686821200008

• Donor-Recipient Age Mismatch and Long-Term Graft Outcomes After Adolescent Liver Transplant. JAMA network open Nakayama, T., Jensen, A. R., Attia, A., Ahn, D. J., Firl, D. J., Kwong, A., Charu, V., Melcher, M. L., Esquivel, C. O., Sasaki, K. 2026; 9 (1): e2552779

  Abstract

  Importance: Donor-recipient age mismatch is an established risk factor in adult liver transplants (LTs), yet its effect in adolescents, who require long-term graft durability, has not been fully characterized. Despite pediatric prioritization, some adolescent donor livers are allocated to adults, limiting access to age-matched grafts for adolescents.Objective: To assess whether a donor-recipient age difference of 10 or more years is associated with inferior graft survival in LTs among adolescents and to estimate the benefits of broader geographic sharing of adolescent donor livers.Design, Setting, and Participants: This retrospective, registry-based case-control study used data from the Organ Procurement & Transplantation Network database, a nationwide US transplant registry. Participants were adolescents aged 12 to 17 years who received liver-only grafts from donation after brain death between March 1, 2002, and December 31, 2024, with follow-up until April 4, 2025. Propensity score matching (1:1) was performed on graft type and size mismatch, donor sex, donor-recipient sex mismatch, transplant center volume, and recipient variables.Exposure: Donor-recipient age difference of 10 or more years (age-mismatched graft) vs less than 10 years (age-matched graft).Main Outcomes and Measures: The primary outcome was 10-year graft survival. The secondary outcome was 10-year overall survival. Waiting time to an age-matched graft offer under alternative donor-sharing radii (1500 nautical miles [NM], 1000 NM, or no limit vs 500 NM) were also estimated.Results: Among 2020 adolescents receiving LTs (median age, 15.0 [IQR, 13.0-16.0] years; 1081 [53.5%] female), 612 (30.3%) received age-mismatched grafts (median donor age, 36.0 [IQR, 29.0-45.0] years) and 1408 (69.7%) received age-matched grafts (median donor age, 16.0 [IQR, 13.0-17.0] years). The age-mismatched group had a higher proportion of recipient candidates in the intensive care unit at transplant (287 [46.9%] vs 250 [17.8%]; P<.001). After propensity score matching (n=526 per group), 10-year graft survival was 61.5% in the age-mismatched group and 74.2% in the age-matched group (P<.001), with consistent results across recipients' pretransplant hospitalization status. A simulation estimated that expanding the adolescent allocation radius to 1000 NM would allow 90% of adolescent candidates to receive age-matched offers within 15 days, compared with 44 days under the current 500-NM limit.Conclusions and Relevance: In this case-control study of a US national cohort of adolescents receiving LT, donor-recipient age mismatch of 10 or more years was associated with inferior graft survival. Broader allocation of adolescent donors may improve access to age-matched grafts and long-term outcomes.

  View details for DOI 10.1001/jamanetworkopen.2025.52779

  View details for PubMedID 41499116

• Initial Experience with Routine Post-Operative Contrast Enhanced Ultrasound Following Pediatric Whole and Partial Deceased Donor Liver Transplant York, T., Attia, A., Nakayama, T., Yu, J., Fu, S., Hanna, K., Ahn, D., Badshah, J., Ebel, N., Alrabadi, L., Czepiel, K., Melcher, M., Pham, K., Busque, S., Rubesova, E., Kirchner, V. ELSEVIER SCIENCE INC. 2026

  View details for Web of Science ID 001684522300010

• When Offers Descend: Pathway, Timing, and Outcomes in Liver Transplantation Attia, A., Nakayama, T., Ahn, D., York, T., Sasaki, K. ELSEVIER SCIENCE INC. 2026

  View details for Web of Science ID 001684210000071

• Association between volume and outcomes in pediatric kidney transplantation Fu, S., Nakayama, T., Ahn, D., Attia, A., Sasaki, K., Pham, T. ELSEVIER SCIENCE INC. 2026

  View details for Web of Science ID 001684210000043

• Highly Sensitized Pediatric Kidney Candidates Have Reduced Access to Kidney Transplant Following the Implementation of Donor Concentric Circle Allocation Nakayama, T., Ahn, D., Attia, A., Sasaki, K., Pham, T. ELSEVIER SCIENCE INC. 2026

  View details for Web of Science ID 001684210000061

• Use of Non-Standardized Exceptions among Pediatric Liver Transplant Candidates in the PELD vs PELD-Cr Eras Ahn, D., Nakayama, T., Attia, A., Sasaki, K., Pham, T. ELSEVIER SCIENCE INC. 2026

  View details for Web of Science ID 001684522300082

• Renal Resistance on Hypothermic Machine Perfusion and Acceptance of Deceased Donor Kidney Allografts. Journal of the American Society of Nephrology : JASN Nakayama, T., Attia, A., Ahn, D. J., McCabe, M., Endo, Y., Kashyap, R. S., Pham, T. A., Melcher, M. L., Sasaki, K., Bekki, Y. 2025

  View details for DOI 10.1681/ASN.0000000986

  View details for PubMedID 41563235

• Complications and Status Upgrades among Adult Heart Transplant Candidates with Durable LVADs: Waiting 6 to 8 Years for Status Escalation Is Too Long. medRxiv : the preprint server for health sciences Ahn, D. J., Attia, A., Nakayama, T., Narang, N., Khush, K. K., Parker, W., Sasaki, K. 2025

  Abstract

  Introduction: After the 2018 allocation policy change, the rate of listings and transplants with durable LVADs has decreased significantly in favor of bridging patients from temporary mechanical circulatory support to heart transplant. The Organ Procurement and Transplantation Network (OPTN) recently approved a policy, to be implemented in September 2026, stipulating that patients supported by durable LVADs for 6 and 8 years will obtain statuses 3 and 2, respectively.Methods: Using OPTN data, we identified all adult heart transplant candidates with a durable LVAD implanted between October 18, 2018 and May 31, 2025. We estimated the cumulative incidence of status upgrades and durable LVAD-related complications, treating transplantation and waitlist removal before experiencing complications as competing events. We also assessed how the composition of the adult heart transplant waitlist on June 1, 2025 would have changed based on the upcoming policy change.Results: During the study period, 3,881 adult patients were listed for heart transplant with a durable LVAD. 3,182 (82.0%) of the durable LVADs were Abbott HeartMate 3, 568 (14.6%) were Medtronic Heartware HVAD, and 91 (2.3%) were Abbott HeartMate II. Transplant centers submitted a total of 6,924 justifications for status upgrades due to LVAD-related complications (6.3% status 1, 34.3% status 2, and 59.4% status 3) for 1,500 (38.6%) of these patients, with a median of 3 per patient. The cumulative incidence of complications or status upgrades was 38.6% [95% CI (37.1%, 40.2%)]. Nearly all of the 2,381 patients who did not experience any complication or status upgrade during listing were removed from the waitlist by 6 years. Had the upcoming OPTN policy change been implemented on June 1, 2025, the proportion of the waitlist that would have achieved higher priority status instantaneously was 0.06%.Conclusions: The cumulative incidence of status upgrades and complications among heart transplant candidates with durable LVADs was nearly 40% within 6 years of device implantation. The upcoming OPTN policy to escalate patients to statuses 3 and 2 after 6 and 8 years of durable LVAD support, respectively, is unlikely to make a meaningful impact on waitlist priority status.

  View details for DOI 10.1101/2025.09.22.25336215

  View details for PubMedID 41040709

• High Rate of Transplantation Prior to Review of Status Exception Requests among Adult Heart Transplant Candidates. medRxiv : the preprint server for health sciences Ahn, D. J., Nakayama, T., Attia, A., White, M., Eap, D., Narang, N., Khush, K. K., Parker, W., Sasaki, K. 2025

  Abstract

  In the United States heart allocation system, when transplant centers submit applications for status exceptions to increase waitlist priority, patients obtain the requested status upgrades immediately while their applications are sent to the regional review boards (RRBs) and reviewed retrospectively. How much time elapses between obtaining a status upgrade through exception and application receipt by the RRBs and how often transplants occur during this period is unknown.Using the Scientific Registry of Transplant Recipients (SRTR), we identified all adult heart transplant candidates listed between October 18, 2018 and December 31, 2023 with submitted applications for status exceptions. We assessed 1) the amount of time elapsed between submission of exception applications and their receipt by the RRBs and 2) the rate of heart transplantation during this "travel" time, stratified by whether the applications were eventually approved or denied. Additionally, using complete match run data, we estimated how many listed patients were skipped by candidates who received transplants with exceptions that were ultimately denied.135 transplant centers submitted status exception requests on behalf of 8,269 adult candidates during the study period, of whom 608 (7.4%) received a denial at least once. The median time from obtaining higher priority statuses immediately via exceptions to application receipt by the RRBs was 3 days. 2,087 out of 8,269 (25.2%) patients received transplants before the RRBs even received their applications, with 115 (18.9%) among 608 with eventual denials and 1,972 (25.7%) among 7,661 with approvals. The cumulative incidence of heart transplantation before application receipt for eventual denials was 19.1% (95% CI [16.0%, 22.3%]) and that for approvals was 26.2% (95% CI [25.2%, 27.1%]) (p < 0.001) at 2 weeks. Based on match run data, the 115 patients who received transplants with denied exceptions bypassed more than seven thousand potential transplant recipients.More than 25% of patients with status exception requests receive heart transplants before their applications are even received by their respective RRBs, let alone reviewed. This raises significant concerns about the efficacy and fairness of retrospective review of exception requests for the allocation of valuable donor hearts.

  View details for DOI 10.1101/2025.09.12.25335606

  View details for PubMedID 41001456

  View details for PubMedCentralID PMC12458605

• UK liver transplantation allocation algorithm: transplant benefit score - Authors' reply. Lancet (London, England) Stutchfield, B. M., Attia, A., Rowe, I. A., Harrison, E. M., Gordon-Walker, T. 2023; 402 (10399): 371-372

  View details for DOI 10.1016/S0140-6736(23)01307-7

  View details for PubMedID 37516542

• Management of temporary epicardial pacing wires in the cardiac surgical patient BRITISH JOURNAL OF HOSPITAL MEDICINE Francis, J., Prothasis, S., Hegde, R., Attia, A., Buchan, K. 2021; 82 (6): 1-7

  Abstract

  Temporary epicardial pacing wires are used after cardiothoracic surgery to maintain a stable cardiac rhythm. They must be distinguished from the more commonly encountered transvenous temporary pacing wires, which are often used in coronary care units for the same purpose. Patients with temporary epicardial pacing wires may be transferred to hospital wards where these wires are not usually encountered, such as COVID wards, the general intensive care unit, the coronary care unit or general surgical wards if a laparotomy was required in the early period following cardiac surgery. Serious complications may arise in managing patients with temporary epicardial pacing wires, which are well known in the cardiothoracic unit but not so well known elsewhere in the hospital. This article discusses the dangers associated with the management of temporary epicardial pacing wires in adult patients, some of which are common to temporary transvenous pacing wires and others are unique to temporary epicardial pacing wires.

  View details for DOI 10.12968/hmed.2021.0079

  View details for Web of Science ID 000669782800014

  View details for PubMedID 34191570