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This issue tracks the recipient from the waiting list through to long-term survival, with cardiovascular risk as the connecting thread. A narrative framework revisits how to stratify and optimise the heart before listing, while a US National Inpatient Sample analysis quantifies what happens when that risk is realised during the transplant admission itself. Longer-term mortality is picked up by a meta-analysis showing cancer kills transplant recipients at more than twice the population rate, with the excess concentrated in lymphoma rather than the malignancies we screen hardest for. The immunology strand is represented by serum proteomics that pull apart isolated microvascular inflammation from classical antibody-mediated rejection, offering a possible non-invasive read on a phenotype the 2022 Banff update only recently carved out. Infection appears twice — a UK meta-analysis dispelling a presumed link between delayed graft function and BK viraemia, and a contemporary cohort tying early bloodstream infection to drains, length of stay, and worse graft and patient survival. The issue closes on the supply side: a machine-learning policy for placing hard-to-place kidneys faster, and a Delphi consensus defining what a high-quality living-donor evaluation should look like. Together the papers span cardiometabolic optimisation, rejection biomarkers, infection, donor utilisation, and living donation — the levers that decide whether a graft is ever offered and how long it lasts.
2. Major Cardiovascular Complications of Index Kidney Transplantation Hospitalizations: A National Inpatient Sample Analysis.
Goble SR, Leventhal TM, Parekh JR. Transplant Direct, 2026. PMID: 42453568.
This retrospective, cross-sectional study used the US National Inpatient Sample from 2016 to 2022 to measure how often serious cardiac events complicate the transplant admission itself, filling a gap in generalisable data on perioperative cardiovascular risk. Cardiac events were defined broadly to include cardiac arrest, cardiogenic shock, acute myocardial infarction, ventricular tachycardia, and related interventions such as resuscitation, ECMO, percutaneous coronary intervention, cardiac catheterisation, or intra-aortic balloon pump. Across roughly 139,720 kidney transplant hospitalisations, a cardiac event occurred in 3,165 (2.3%), and these patients were older (mean 59.2 versus 52.3 years) with a heavier comorbidity load (Charlson index 4.4 versus 3.2). The clinical cost was steep: in-hospital mortality reached 9.2% among those with a cardiac event against 0.4% in those without, and length of stay (13.4 versus 5.7 days) and cost (roughly $108,900 versus $67,000) rose accordingly. A cardiac intervention was recorded in 0.8% of recipients and carried a 16.6% mortality. On modelling, a Charlson index above 4 was strongly associated with cardiac events (odds ratio 4.95, 95% CI 4.21–5.82), alongside older age, male sex, and established cardiovascular and diabetic comorbidity. As an administrative-database study it captures coded events during the index stay only and cannot adjust for unmeasured perioperative detail, and US case mix may not mirror UK selection. For UK practice it puts a concrete number on the peri-transplant cardiac hazard that pre-listing optimisation is meant to mitigate, and supports counselling higher-comorbidity candidates on the admission-level risk they carry.
4. Serum Proteomic Profiles of Microvascular Inflammation in Donor-specific Antibody-negative and C4d-negative in Kidney Transplantation.
Koh HB, Kim HJ, Kim HW, Ko B, Kang M, Kim HJ, Lee J, Kim MS, Kim BS, Huh KH, Yang J. Transplantation, 2026. PMID: 42441560.
This study interrogated the biology of isolated microvascular inflammation (iMVI), the microvascular-inflammation-positive but DSA-negative and C4d-negative phenotype that the 2022 Banff classification separated out from classical antibody-mediated rejection (AMR) and whose meaning remains unsettled. Recipients biopsied between 2013 and 2024 were grouped into iMVI, AMR, and acute tubular injury, and after propensity-score matching an 80-patient main cohort (30 iMVI, 30 AMR, 20 acute tubular injury) was assembled, with a separate 88-patient validation cohort that also included T-cell-mediated rejection. Serum was profiled using a proximity extension assay. The two rejection phenotypes looked immunologically distinct: iMVI was enriched for innate and cytotoxic mediators — among them TNFRSF9, PD-L1, IL-15 receptor alpha, and CX3CL1, with natural-killer-cell and leukocyte-migration pathways prominent — whereas AMR was dominated by adaptive and humoral signals such as IL-33, IL-2, and TRAIL with immunoglobulin-production and interferon-gamma pathways. Protein-based risk scores discriminated well in the main cohort (area under the curve 0.856 for iMVI and 0.879 for AMR) and retained significance on validation (0.708 and 0.689), and several iMVI-enriched proteins tracked with a higher risk of death-censored graft loss. As a two-cohort observational study with modest matched numbers, it establishes association and discrimination rather than a validated clinical assay. For UK practice it strengthens the case that isolated microvascular inflammation is a real, prognostically adverse entity distinct from AMR, and points toward serum proteomics as a future non-invasive adjunct to biopsy phenotyping.
5. No association between delayed graft function and BK polyomavirus infection reactivation after kidney transplantation: a systematic review and meta-analysis.
Kitrungphaiboon T, Evison F, Gallier S, Sharif A. Front Nephrol, 2026. PMID: 42416210.
This UK study paired a single-centre cohort analysis with a systematic review and meta-analysis to test whether delayed graft function (DGF) predisposes to BK polyomavirus (BKPyV) DNAemia, a relationship that has been assumed but never firmly established. In the Birmingham cohort of 1,770 recipients transplanted between 2007 and 2018, followed for a median of 5.3 years (IQR 2.7–8.7), BKPyV DNAemia was associated on univariate testing with male sex (8.3% versus 5.3%, p=0.017), ABO-incompatible transplantation (10.3% versus 4.6%, p=0.004), and DGF (9.0% versus 6.3%, p=0.048). Once adjusted, however, only male sex and ABO-incompatible transplantation remained independently associated, and the apparent DGF signal fell away. The authors then identified 11 published studies and, incorporating their own cohort, pooled the data with a DerSimonian-Laird random-effects model, finding no association between DGF and BKPyV DNAemia (odds ratio 1.00, 95% CI 0.67–1.50). The evidence base remains observational and clinically heterogeneous, and viraemia rather than nephropathy was the endpoint, so residual confounding cannot be excluded. For UK practice it argues against treating DGF as an independent trigger for intensified BK surveillance, redirecting attention to recipient sex and ABO-incompatible status when judging who warrants closer virological monitoring.
6. Early Onset Bacteremia in Kidney Transplant Recipients in the Current Era.
Hasan L, Shrestha NK, Duck M, Augustine J, Fatica R, Wee A, Koval CE. Transpl Infect Dis, 2026. PMID: 42464458.
This single-centre retrospective study examined contemporary risk factors and outcomes of early bloodstream infection (eBSI) after kidney transplantation, defined as bacteraemia within 90 days, using a case-control design matched for age and sex. Among 1,408 recipients transplanted between 2019 and 2023, 75 (5.3%) developed an eBSI at a median of 21 days (IQR 12–42.5). On multivariable analysis, two modifiable, care-related exposures stood out: each doubling of hospital length of stay was independently associated with a 49% increase in eBSI risk (odds ratio 1.49, 95% CI 1.19–1.91), and each doubling of postsurgical drain retention time with a 68% increase (odds ratio 1.68, 95% CI 1.17–2.48). The downstream consequences were substantial, with eBSI associated with markedly higher one-year mortality (adjusted hazard ratio 3.32, 95% CI 1.51–7.28) and three-year graft failure (adjusted hazard ratio 2.78, 95% CI 1.31–5.93). As a single-centre matched analysis it cannot fully separate infection from the frailty and complications that also prolong stay and drain use, and its microbiology reflects local epidemiology. For UK practice it reinforces the surgical and nursing basics — minimising drain dwell time and hospital stay — as concrete, low-cost levers to reduce a complication that measurably worsens both graft and patient survival.
7. Improving hard-to-place kidney allocation: A machine learning approach to center ranking.
Berry S, Görgülü B, Tunç S, Cevik M, Ellis MJ. Health Care Manag Sci, 2026. PMID: 42455365.
This study proposes a machine-learning policy to speed the expedited, out-of-sequence placement of hard-to-place deceased-donor kidneys, a process that currently leans on the subjective judgement of allocating clinicians and contributes to organ non-utilisation. Using national deceased-donor and kidney-offer data, the authors built an offer-level dataset combining donor- and centre-specific features, then ranked transplant centres by their predicted centre-level probability of accepting a given offer so that organs are directed first to the units most likely to use them. They also applied interpretability tools to expose which donor and centre factors drive acceptance, addressing the “black box” objection that often stalls adoption of such models in allocation. The headline efficiency gain was a reduction in the average number of centres that had to be approached before a kidney was placed — roughly fourfold across all kidneys and tenfold for the hard-to-place subset. As a retrospective, data-driven simulation on national US data, it demonstrates potential placement efficiency rather than prospective outcomes, and transferability to another allocation system is untested. For UK practice, where fast-track and out-of-sequence offering of marginal kidneys is a live operational concern, it signals how predictive center-ranking could cut cold ischaemia and reduce discard, while underlining that any such tool would need validation against the UK offering scheme before use.
8. Defining a High-Quality Living Kidney Donor Evaluation: A Delphi Survey and Consensus Conference Summary Report.
Yohanna S, Naylor KL, Holtby L, Sontrop JM, Alam A, Cheal B, Dipchand C, Garg AX, Gill J, Habbous S, Hingwala J, John P, King J, Koch M, Lam NN, Morrison S, Pisapia C, Reich M, Sandal S, Settee C, Smith T, Thibodeau C, van der Linde L, Wang C. Can J Kidney Health Dis, 2026. PMID: 42459354.
This Canadian consensus project used a Delphi method and a national conference to define what a high-quality living kidney donor evaluation should deliver, motivated by the reality that donors frequently describe the assessment — often lengthy, complex, and inefficient — as the hardest part of donating. Four multidisciplinary working groups, involving living donors (n=8), healthcare professionals (n=11), and administrators (n=3), developed recommendations grounded in both evidence and lived experience, culminating in a virtual consensus conference in September 2024 attended by more than 100 donors, nurses, nephrologists, surgeons, researchers, and transplant-organisation representatives. Of 42 recommendations put through the e-Delphi process, 35 reached consensus at the pre-specified 75% threshold, though the evidence underpinning them was uneven — 92% rested on moderate-quality evidence and 8% on none, exposing how thinly several aspects of donor evaluation are studied. The agreed recommendations clustered into four themes: raising donor numbers and evaluation efficiency (for example, deciding eligibility within three to six months), strengthening programme resources and donor reimbursement toward financial neutrality, ensuring a donor-centred process with metrics such as donor satisfaction, and promoting consistency and evidence-based practice across programmes. As a consensus exercise it reflects expert and donor opinion rather than trial evidence, and its metrics are aspirational until validated. For UK practice it offers a ready benchmarking framework for living-donor programmes under pressure to shorten and humanise the workup, and a reminder that donor experience and financial neutrality belong alongside clinical safety as quality measures.
Generated 2026-07-18 from PubMed search results for kidney transplantation published 2026-07-04 to 2026-07-18. Articles already recorded in prior issues were excluded. PubMed is the source of all metadata and abstracts.
How this digest is made: From a literature-search skill to a self-running evidence digest.