Kidney Transplant RecipientDAN-PTRAIIINCT07531966
Vascular Complications After Kidney Transplantation
An observational study of Kidney Transplant Recipient and Kidney Transplant; Complications, run by University of Aarhus at 3 sites in Denmark.
Trial summary
To determine the incidence of arterial inflow problems and venous outflow problems as causes of impaired renal function and/or treatment-resistant hypertension after kidney transplantation, when all kidney-transplant recipients in Denmark are evaluated according to uniform, well-defined clinical criteria. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Kidney Transplant Recipient, Kidney Transplant; Complications, Transplant Renal Artery Stenosis
- What is being tested?
- Catheter-based angiography, Measurement of translesional pressure gradients and Intravascular ultrasound (IVUS)
- Type of treatment
- Surgery or procedure
- How many people
- 60 participants
- Where
- 3 sitesDenmark
- Study dates
- 22 May 2026to 1 Jun 2031
- How long will I take part?
- 10 Years
- Phase
- Observational
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: National prospective multicenter study with a primary endpoint at 3 months and annual follow-up for up to 10 years post-intervention, evaluating renal function, blood pressure, and clinical events. Patients with vascular complications, predominantly transplant renal artery stenosis (TRAS) following kidney transplantation, who meet at least one of the clinical inclusion criteria, may be enrolled in the study.
Who may be able to join
- 1. At least one of the following clinical criteria (1 or 2) must be fulfilled:
- Graft dysfunction, defined by at least one of the following:
- Acute reduction in estimated glomerular filtration rate (eGFR) >15% on two consecutive measurements at least 2 weeks apart, with other causes excluded (rejection, obstruction, infection).
- eGFR <50% of the expected value 30 days after kidney transplantation of unknown cause.
- Decline in eGFR >30% after initiation of an angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker.
- Persistent resistant hypertension for more than 6 weeks after kidney transplantation, defined as:
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- 24-hour ambulatory systolic blood pressure >130 mmHg despite treatment with at least three classes of antihypertensive medication at maximally tolerated doses (including diuretics, if tolerated).
- Together with at least one of the following radiological criteria:
- CT or MR angiography demonstrating a lumen reduction ≥50%.
- Doppler ultrasound showing:
- Peak systolic velocity in the renal artery ≥200 cm/s and a renal-renal ratio (velocity at stenosis / velocity in distal artery) >4.
- Acceleration time >70 ms in intrarenal arteries.
- 2. In cases of strong clinical suspicion of a vascular complication where CT or MR angiography cannot reliably exclude graft artery or vein stenosis, patients may be referred for confirmatory invasive investigations.
- Before PTA, catheter-based angiography and translesional pressure measurements are performed to confirm whether the patient meets the radiological eligibility criterion for PTA:
- Stenosis ≥70%.
- Stenosis 50-69% if at least one of the following criteria is met:
- Mean translesional pressure gradient ≥10 mmHg.
- Systolic pressure gradient ≥20 mmHg.
- Renal Pd/Pa ≤0.8.
- If pressure measurements cannot be obtained, treatment is based on the operator's clinical judgement.
Who cannot join
- Inability to provide informed consent.
- Concurrent biopsy demonstrating rejection requiring treatment.
- Pregnancy.
- Previous PTA of the same vessel.
- Patients unable to tolerate any form of antithrombotic therapy and therefore not eligible for stent placement.
Trial locations and contacts
3 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Henrik Birn, MD, DMSc contact
Denmark3 sites, 3 recruiting
- Recruiting
Aarhus University Hospital
Aarhus, 8200
Mark Reinhard, MD, PhD, markrein@rm.dk
- Recruiting
Rigshospitalet
Copenhagen, 2100
Søren S Sørensen, MD, DMSc, Soeren.Schwartz.Soerensen@regionh.dk
- Recruiting
Odense University Hospital
Odense, 5000
Claus Bistrup, MD, PhD, Claus.Bistrup@rsyd.dk
About this study
Official title: Vascular Complications After Kidney Transplantation: A Prospective National Multicenter Study - The DAN-PTRAIII Study
- To determine the incidence of arterial inflow problems and venous outflow problems as causes of impaired renal function and/or treatment-resistant hypertension after kidney transplantation, when all kidney-transplant recipients in Denmark are evaluated according to uniform, well-defined clinical criteria.
- To investigate the efficacy and safety of catheter-based balloon treatment (percutaneous transluminal angioplasty, PTA) for these vascular complications, of which transplant renal artery stenosis is by far the most common.
- To assess whether novel imaging and functional diagnostic methods can predict treatment response.
Read the detailed description
Kidney transplantation is performed 250-300 times annually in Denmark and substantially improves survival, quality of life, and reduces the burden of comorbidities in patients with end-stage kidney disease. Despite these benefits, vascular complications, particularly transplant renal artery stenosis (TRAS), remain a major cause of morbidity. Reported incidence of TRAS varies widely (1-23%), reflecting retrospective study designs and inconsistent diagnostic criteria. TRAS are classified into three main types: anastomotic (TRAS-A), post-anastomotic (TRAS-P), and long-segment bend/kink (TRAS-B), with most cases diagnosed within the first two years post-transplant. Severe stenoses can critically impair graft perfusion, leading to reduced renal function and treatment-resistant hypertension.
Percutaneous transluminal angioplasty (PTA) for TRAS is a well-established procedure performed according to the same principles as coronary balloon angioplasty; however, the role of stent placement remains uncertain. PTA without stenting is associated with higher restenosis rates compared to PTA with stenting, yet evidence regarding graft function, survival, and blood-pressure control remains conflicting.
Adverse events related to PTA occur in approximately 10% of patients and are generally mild. Serious adverse events are observed in fewer than 5% of patients and include procedure-related internal bleeding and vascular access-site complications. Severe internal bleeding may require blood transfusion and endovascular vessel occlusion and can, in rare cases, result in loss of the transplanted kidney. Access-site vascular complications may present as bleeding, thrombosis, or pseudoaneurysm.
Against this background, the nationwide prospective multicentre DAN-PTRAIII study aims to establish the true incidence of arterial inflow and venous outflow problems in Danish kidney-transplant recipients, evaluate the efficacy and safety of balloon angioplasty, and explore novel imaging and functional diagnostic methods for predicting treatment response.
- Conditions
- Kidney Transplant Recipient, Kidney Transplant; Complications, Transplant Renal Artery Stenosis, Renovascular Disease, Renal Transplant Graft Failure, Renovascular Hypertension
- Being tested
- Catheter-based angiography, Measurement of translesional pressure gradients, Intravascular ultrasound (IVUS), Percutaneous transluminal angioplasty (PTA)
- Keywords
- Kidney Transplant; Complications, Transplant Renal Artery Stenosis, renovascular disease, Percutaneous transluminal angioplasty
- Medical subject headings
- Hypertension, Renovascular, Heart Failure
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Catheter-based angiographyDiagnostic test
Catheter-based angiography performed in accordance with the study protocol.
Measurement of translesional pressure gradientsDiagnostic test
Measurement of translesional pressure gradients performed in accordance with the study protocol.
Intravascular ultrasound (IVUS)Diagnostic test
Intravascular ultrasound (IVUS) performed in accordance with the study protocol.
Percutaneous transluminal angioplasty (PTA)Procedure or surgery
Percutaneous transluminal angioplasty (PTA) is performed in accordance with the study protocol. As a general principle, bare-metal stents (BMS) are used. Drug-eluting stents (DES) may be considered when the arterial lumen diameter is < 4-5 mm. In stenoses where stent placement carries a risk of side-branch occlusion, PTA is performed without stent implantation and most often with a drug-coated balloon (DCB).
| Study group | Role | What they receive |
|---|---|---|
| Kidney Transplant Recipients | Patients who meet well-defined clinical and radiological criteria for significant vascular complications after kidney transplantation, with transplant renal artery stenosis being by far the most common. Receives: Diagnostic Test: Catheter-based angiography; Diagnostic Test: Measurement of translesional pressure gradients; Diagnostic Test: Intravascular ultrasound (IVUS); Procedure: Percutaneous transluminal angioplasty (PTA) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in measured glomerular filtration rate (mGFR).
Change in measured glomerular filtration rate (mGFR) at 3 months post-PTA compared with baseline.
Measured: Baseline and 3 months post-PTA.
Secondary outcomes (16)
Change in estimated glomerular filtration rate (eGFR).
Change in estimated glomerular filtration rate (eGFR) measured on day 1, day 7, day 21, at 6 weeks, at 3 and 12 months, and annually thereafter for up to 10 years post-PTA, compared with baseline.
Measured: Baseline, Day 1, Day 7, Day 21, 6 weeks, 3 months, 12 months, and annually thereafter for up to 10 years post-PTA.
Change in home systolic blood pressure.
Change in home systolic blood pressure measured on day 7, day 21, at 6 weeks, at 3 and 12 months, and annually thereafter for up to 10 years post-PTA, compared with baseline.
Measured: Baseline, Day 7, Day 21, 6 weeks, 3 months, 12 months, and annually thereafter for up to 10 years post-PTA.
Change in attended automated office systolic blood pressure.
Change in attended automated office systolic blood pressure measured at 3, 12, and 24 months post-PTA, compared with baseline.
Measured: Baseline, 3 months, 12 months, and 24 months post-PTA.
Change in unattended automated office systolic blood pressure.
Change in unattended automated office systolic blood pressure measured at 3, 12, and 24 months post-PTA, compared with baseline.
Measured: Baseline, 3 months, 12 months, and 24 months post-PTA.
Change in 24-hour ambulatory systolic blood pressure.
Change in 24-hour ambulatory systolic blood pressure measured at 3, 12, and 24 months post-PTA, compared with baseline.
Measured: Baseline, 3 months, 12 months, and 24 months post-PTA.
Change in defined daily dose (DDD) of antihypertensive medications.
Change in defined daily dose (DDD) of antihypertensive medications at 3, 12, and 24 months post-PTA compared with baseline.
Measured: Baseline, 3 months, 12 months, and 24 months post-PTA.
Change in the number of antihypertensive medications.
Change in the number of antihypertensive medications at 3, 12, and 24 months post-PTA compared with baseline.
Measured: Baseline, 3 months, 12 months, and 24 months post-PTA.
Change in 24-hour ambulatory systolic blood pressure adjusted for changes in antihypertensive medication.
Change in 24-hour ambulatory systolic blood pressure measured at 3, 12, and 24 months post-PTA, compared with baseline, adjusted for changes in antihypertensive medication (5 mmHg per DDD).
Measured: Baseline, 3 months, 12 months, and 24 months post-PTA.
Health status on 12-item Short Form Health Survey (SF-12).
Change in 12-item Short Form Health Survey (SF-12) scores at 3 months post-PTA, compared with baseline.
Scores range from 0 to 100, with higher scores indicating better physical and mental health functioning.
Measured: Baseline and 3 months post-PTA.
Number of clinical events after PTA.
Cardiovascular and renal events are defined according to the criteria used in the DAPA-CKD study, with the modification that end-stage kidney disease is defined exclusively as either kidney transplantation or chronic dialysis. After PTA treatment, the following clinical events will be recorded for 10 years:
- Cardiovascular death
- Renal death
- Death from non-cardiovascular and non-renal causes
- Undetermined cause of death
- Stroke
- Myocardial infarction
- Hospitalization for heart failure
- Reduction in eGFR ≥50% from baseline for ≥28 days, not fulfilling the definition of end-stage kidney disease
- End-stage kidney disease, defined as kidney transplantation or chronic dialysis for ≥28 days
- Biopsy-proven rejection
- Need for repeat PTA due to restenosis or in-stent thrombosis
- Other relevant clinical events
Measured: 10 years post-PTA.
Number of adverse events (AEs) occurring within 30 days after the procedure
All adverse events (AEs) occurring within 30 days after the procedure will be recorded and classified according to seriousness, relationship to the procedure, and whether the event occurs within ≤24 hours (periprocedural) or >24 hours through day 30 (post-interventional):
- Vessel rupture
- Vessel dissection
- Vessel occlusion
- Vessel perforation
- Stent thrombosis
- Embolic events to the kidney or the peripheral circulation (upper or lower extremity, depending on the access route)
- Pulmonary oedema
- Major bleeding requiring transfusion
- Embolisation due to bleeding or another adverse event
- Nephrectomy due to bleeding or another adverse event
- Access-site or access-vessel complication requiring additional hospitalisation, blood transfusion, or surgical intervention
- Requirement for acute dialysis
- Clinical events, including all-cause mortality, as defined above
- Other relevant adverse events (AEs)
Measured: 30 days post-PTA.
Doppler ultrasound.
Diagnostic utility and predictive value for treatment response to PTA.
Measured: Baseline and 3 months post-PTA.
Invasive pressure measurements across stenoses.
Diagnostic utility and predictive value for treatment response to PTA.
Measured: Baseline and 3 months post-PTA.
Intravascular ultrasound.
Diagnostic utility and predictive value for treatment response to PTA.
Measured: Baseline and 3 months post-PTA.
Non-invasive fractional flow reserve computed tomography (FFR-CT) / computational fluid dynamics (CFD) simulation.
Diagnostic utility and predictive value for treatment response to PTA.
Measured: Baseline and 3 months post-PTA.
Functional magnetic resonance imaging.
Diagnostic utility and predictive value for treatment response to PTA.
Measured: Baseline and 3 months post-PTA.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Apr 2026
- Study start22 May 2026
- Primary completion31 Mar 2031 (estimated)
- Study completion1 Jun 2031 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Kidney Transplant RecipientStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 60 participants (estimated)
- Target duration
- 10 Years
Sponsor and investigators
- Lead sponsor
- University of Aarhus
- Sponsor type
- University, hospital or other
- Collaborators
- Aarhus University Hospital, Copenhagen University Hospital, Rigshospitalet, Odense University Hospital, Aalborg University Hospital, Gødstrup Hospital, Holbaek Sygehus, Amsterdam UMC, The Augustinus Foundation, Denmark.
- Responsible party
- Sponsor
- Investigators
- Mark Reinhard, MD, PhD, Principal investigator, Aarhus University Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07531966
- Sponsor's protocol ID
- DAN-PTRAIII
- Acronym
- DAN-PTRAIII
- Status last verified
- May 2026
- First submitted
- 1 Apr 2026
- Last updated
- 16 Oct 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No