An interventional study of Multiparametric assessment and Structured usual care in Kidney Transplantation, Delayed Graft Function and Fluid Overload, sponsored by Hospital Universitario Ramon y Cajal. Not yet recruiting. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-30.
Sponsored by Hospital Universitario Ramon y Cajal · Not applicable, Interventional, and Treatment
After a kidney transplant, the amount of fluid in the body must be carefully balanced. Too much fluid can accumulate in the lungs, the tissues and the new kidney itself and may delay its recovery; too little fluid can also damage it. In current practice, doctors judge fluid status mainly by physical examination, body weight and urine output, which are imprecise and often late signs.
Two painless bedside tests can measure fluid status more accurately: bioimpedance, which estimates excess body water through skin electrodes, and ultrasound of the lungs, the large abdominal veins and the transplanted kidney. In a previous study by our group, these tests detected fluid overload that physical examination missed. Whether using their results to guide treatment actually improves the outcome of the transplant is unknown.
This trial will compare two ways of managing fluids during the first month after transplantation: one guided by these tests and a treatment algorithm, and one based on usual clinical assessment. The aim is to find out whether test-guided management improves survival, reduces the need for dialysis in the first week and leads to better kidney function at one month.
RATIONALE Fluid management after kidney transplantation is a two-sided problem. The newly implanted graft is an encapsulated, denervated organ with interrupted lymphatic drainage and endothelial injury from ischaemia-reperfusion. Venous hypertension and interstitial expansion raise intracapsular pressure, reduce the net filtration gradient and peritubular capillary flow, and may prolong recovery from acute tubular necrosis. At the same time, the post-ischaemic graft has lost autoregulation, so its perfusion becomes pressure-passive and intravascular depletion is equally harmful. A useful monitoring strategy must therefore detect both overload and depletion, and must distinguish between the compartments involved.
Bioimpedance quantifies extracellular overhydration, the venous excess ultrasound score (VExUS) grades systemic venous congestion, and lung ultrasound detects extravascular lung water. In this trial, the intrarenal component of VExUS is obtained from the graft itself, and graft venous pulsatility is added as a confirmatory marker of congestion.
PILOT DATA
A prospective single-centre cohort of 80 kidney transplant recipients (Hospital Universitario Ramón y Cajal, 2023-2024) showed that:
The limitations of the pilot (single centre, a single operator for most examinations, no treatment algorithm, post hoc exclusion of patients with severe outcomes and no concurrent control group) determine the requirements of the present design.
DESIGN RATIONALE Because the intervention is a strategy rather than a test, the trial randomises only the disclosure of assessment results and their translation into a treatment algorithm. Keeping the assessment schedule identical in both arms equalises surveillance intensity, removes the surveillance bias of the pilot study, allows a paired diagnostic comparison with physical examination in every participant and makes contamination of the control arm measurable. Individual randomisation was preferred to cluster randomisation because the small number of centres would make a cluster design inefficient and unstable; contamination is accepted, mitigated (recommendations are delivered only by the ultrasound team) and accounted for in the sample size. The treatment algorithm will be finalised by Delphi consensus among the participating centres and frozen before the first participant is enrolled.
The hierarchical primary endpoint integrates survival, early need for dialysis and graft function, and handles death and graft loss as outcomes rather than as missing data, avoiding the survivorship bias of the pilot study. A single dialysis session for isolated hyperkalaemia in the first 24 hours is excluded from the dialysis level because, in the pilot data, it reflected potassium management rather than graft injury.
MEASUREMENT QUALITY Operators are certified against a central imaging core laboratory before enrolment. Two blinded central readers from different centres read all VExUS and graft venous Doppler examinations and a random 20% of lung ultrasound examinations; the local reading guides management and the central reading is used for analysis. A reliability substudy separates acquisition and interpretation variability, with weighted kappa, Gwet AC1/AC2, intraclass correlation, Bland-Altman analysis and minimal detectable change. Operator drift is monitored with CUSUM charts, with recertification every 6 months.
SAMPLE SIZE The sample size was estimated by Monte Carlo simulation (5,000 iterations) bootstrapping individual data from the 78 deceased-donor recipients of the pilot cohort. Assumptions: no effect on death or graft loss; relative risk of 0.75 for sustained dialysis; an improvement of 5 mL/min/1.73 m2 in eGFR at 1 month; 10% contamination of the control arm; and 5% loss to follow-up. The expected win ratio is 1.33, giving 80% power with a two-sided alpha of 0.05. A blinded sample size re-estimation will be performed at 50% of recruitment, with a predefined cap.
STATISTICAL ANALYSIS The primary analysis follows the intention-to-treat principle using a win ratio stratified by centre and donor type, with win odds, net benefit and the contribution of each hierarchical level. Prespecified sensitivity analyses vary the eGFR tie margin and the dialysis definition, use the per-protocol population, exclude the largest centre and use local instead of central readings. Key secondary outcomes are tested hierarchically to control type I error. Missing 1-month eGFR in participants alive with a functioning graft is handled by multiple imputation.
OVERSIGHT AND ETHICS A blinded adjudication committee reviews every dialysis indication, acute pulmonary oedema, graft loss and the diagnostic reference standard. An independent Data Monitoring Committee reviews safety data every 6 months and performs a non-binding futility analysis at 50% of the information. Concealment of results in the control arm is justified by clinical equipoise: there is no evidence that acting on these measurements improves transplant outcomes, and in haemodialysis a lung ultrasound-guided strategy changed management without improving clinical outcomes. Consent is sought while candidates are on the waiting list, so that the decision is not made under the time pressure of a deceased-donor offer.
83 studies on the registry are indexed under Delayed Graft Function; 15 are open to participants now.
This study's planned enrollment of 650 is above the median of 90 across 62 interventional studies indexed under Delayed Graft Function.
Browse Delayed Graft Function studies →Hospital Universitario Ramon y Cajal is the lead sponsor of 30 studies on the registry; 3 are open to participants now.
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Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
"Guided fluid management": BIA + VExUS adapted to the graft + graft venous pulsatility + lung ultrasound. Results go to the treating team and fluids, diuretics and dialysis are managed according to a predefined algorithm.
Diagnostic Test: Multiparametric assessment · Other: Structured usual care
"Structured usual care": same assessments with results concealed from the treating team. Critical findings are disclosed in both arms.
Bioimpedance and Multiparametric Ultrasound-Guided Fluid Management
Structured usual care
Hierarchical composite of death, graft loss, sustained dialysis and eGFR (win ratio)
Each intervention participant is compared with each control participant within strata (centre, donor type), moving to the next level only if tied: (1) all-cause death (earlier is worse); (2) graft loss, defined as permanent return to dialysis or transplantectomy (earlier is worse); (3) sustained dialysis within 7 days after reperfusion, excluding a single session in the first 24 h for isolated hyperkalaemia (more sessions is worse); (4) eGFR at 1 month, CKD-EPI 2021 creatinine equation (higher is better). Reported as stratified win ratio with 95% CI (Finkelstein-Schoenfeld test), win odds and net benefit.
Time frame: Day 30 post-transplant (dialysis assessed up to day 7; eGFR measured on days 28-35)
Delayed graft function, by dialysis and functional (CRR2) definitions
Proportion of participants requiring any dialysis within the first 7 days after transplantation, and proportion with a creatinine reduction ratio on day 2 below 30%.
Time frame: Day 2 (CRR2) and up to day 7 post-transplant (dialysis)
Number of dialysis sessions
Number of dialysis sessions and days to last dialysis within the first 7 days.
Time frame: Up to day 7 post-transplant
Length of stay
Days from transplantation to discharge from the index admission, analysed with death as a competing event.
Time frame: Up to 90 days post-transplant
Days alive and out of hospital at 30 days
Number of days alive and out of hospital within the first 30 days after transplantation.
Time frame: Day 30 post-transplant
Acute pulmonary oedema
Proportion of participants with acute pulmonary oedema, adjudicated by a blinded committee using clinical, radiological and oxygenation criteria.
Time frame: Up to day 30 post-transplant
Cardiovascular events
Proportion of participants with arrhythmia, acute coronary syndrome, heart failure, stroke, arterial or venous thrombosis, or major bleeding.
Time frame: Up to day 30 post-transplant
30-day readmission
Proportion of participants readmitted after discharge from the index admission, by cause.
Time frame: Up to 30 days after discharge from the index admission
BIA overhydration trajectory
Absolute overhydration (L) measured by bioimpedance spectroscopy at each assessment.
Time frame: Pre-transplant (0-24 h before surgery), days 1, 3 and 7, pre-discharge and month 1 post-transplant
eGFR at 3 and 12 months
Estimated glomerular filtration rate (CKD-EPI 2021 creatinine equation, mL/min/1.73 m²) obtained from medical records.
Time frame: Month 3 and month 12 post-transplant
Acute rejection
Proportion of participants with biopsy-proven or presumptive acute rejection.
Time frame: Up to day 30 post-transplant
Time to detection of fluid overload
Paired comparison of the time from randomisation to first detection of fluid overload by the multiparametric strategy versus physical examination, against a reference standard adjudicated by a blinded committee, with latent class analysis as a sensitivity analysis. All participants.
Time frame: From randomisation to day 7 post-transplant
Diagnostic accuracy of each method
Sensitivity, specificity and likelihood ratios of bioimpedance, VExUS, graft venous pulsatility, lung ultrasound and physical examination against the adjudicated reference standard.
Time frame: Days 1, 3 and 7 and month 1 post-transplant
Inter- and intra-observer reliability
Weighted kappa, Gwet AC1/AC2 and intraclass correlation coefficient (2,1) for VExUS grade, graft venous pulsatility, lung ultrasound B-lines and bioimpedance; minimal detectable change.
Time frame: Days 1, 3 and 7 and month 1 post-transplant
Intervention fidelity
Proportion of assessments in the intervention arm followed by algorithm-concordant management.
Time frame: Days 1, 3 and 7, pre-discharge and month 1 post-transplant
Contamination of the control arm
Cumulative intravenous fluid volume (mL) at days 3 and 7 in the control arm, compared across consecutive calendar periods of recruitment.
Time frame: Day 3 and day 7 post-transplant
Symptomatic hypotension (safety outcome)
Proportion of participants with at least one episode of systolic blood pressure below 90 mmHg accompanied by symptoms or requiring a fluid bolus or vasopressor.
Time frame: Up to day 30 post-transplant
Cumulative intravenous fluid volume and fluid balance
Total intravenous fluid volume administered (mL) and cumulative fluid balance (mL), calculated from the end of surgery.
Time frame: Day 3 and day 7 post-transplant
No study locations are listed for this record.
Plan to share: No
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Hospital Universitario Ramon y Cajal