Vascular Complications After Kidney Transplantation

NCT07531966 | Recruiting DMC

• 1 other identifier: DAN-PTRAIII
• Study Type: observational
• Target: 60
• Locations: 1 country
• Sites: 3

Brief 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.
• 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.

Conditions

Kidney Transplant Recipient; Kidney Transplant; Complications; Transplant Renal Artery Stenosis; Renovascular Disease; Renal Transplant Graft Failure; Renovascular Hypertension; Heart Failure

Keywords

Kidney Transplant; Complications; Transplant Renal Artery Stenosis; renovascular disease; Percutaneous transluminal angioplasty

Outcome Measures

Primary Outcomes (1)

• Change in measured glomerular filtration rate (mGFR).

  Change in measured glomerular filtration rate (mGFR) at 3 months post-PTA compared with baseline.

  Baseline and 3 months post-PTA.

Secondary Outcomes (16)

• Change in estimated glomerular filtration rate (eGFR).

  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.

  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.

  Baseline, 3 months, 12 months, and 24 months post-PTA.

• Change in unattended automated office systolic blood pressure.

  Baseline, 3 months, 12 months, and 24 months post-PTA.

• Change in 24-hour ambulatory systolic blood pressure.

  Baseline, 3 months, 12 months, and 24 months post-PTA.

Study Arms (1)

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.

Diagnostic Test: Catheter-based angiography; Diagnostic Test: Measurement of translesional pressure gradients; Diagnostic Test: Intravascular ultrasound (IVUS); Procedure: Percutaneous transluminal angioplasty (PTA)

Interventions

Measurement of translesional pressure gradients DIAGNOSTIC_TEST

Measurement of translesional pressure gradients performed in accordance with the study protocol.

Kidney Transplant Recipients

Intravascular ultrasound (IVUS) DIAGNOSTIC_TEST

Intravascular ultrasound (IVUS) performed in accordance with the study protocol.

Kidney Transplant Recipients

Catheter-based angiography DIAGNOSTIC_TEST

Catheter-based angiography performed in accordance with the study protocol.

Kidney Transplant Recipients

Percutaneous transluminal angioplasty (PTA) PROCEDURE

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).

Kidney Transplant Recipients

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

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.

You may qualify if:

• \. 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:
• 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.
• \. 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%.

You may not qualify if:

• 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.

Sponsors & Collaborators

• University of Aarhus: lead
• Aarhus University Hospital: collaborator
• Rigshospitalet, Denmark: collaborator
• Odense University Hospital: collaborator
• Aalborg University Hospital: collaborator
• Gødstrup Hospital: collaborator
• Holbaek Sygehus: collaborator
• Amsterdam UMC: collaborator
• The Augustinus Foundation, Denmark.: collaborator

Study Sites (3)

Aarhus University Hospital

Aarhus, 8200, Denmark

RECRUITING

Rigshospitalet

Copenhagen, 2100, Denmark

RECRUITING

Odense University Hospital

Odense, 5000, Denmark

RECRUITING

Biospecimen

Retention: SAMPLES WITH DNA

Whole blood, serum, plasma, and urine.

MeSH Terms

Conditions

Hypertension, Renovascular; Heart Failure

Interventions

Ultrasonography, Interventional; Angioplasty

Condition Hierarchy (Ancestors)

Hypertension, Renal; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Male Urogenital Diseases; Hypertension; Vascular Diseases; Cardiovascular Diseases; Heart Diseases

Intervention Hierarchy (Ancestors)

Ultrasonography; Diagnostic Imaging; Diagnostic Techniques and Procedures; Diagnosis; Minimally Invasive Surgical Procedures; Surgical Procedures, Operative; Catheterization; Therapeutics; Endovascular Procedures; Vascular Surgical Procedures; Cardiovascular Surgical Procedures; Investigative Techniques

Study Officials

• Mark Reinhard, MD, PhD

  Aarhus University Hospital

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Mark Reinhard, MD, PhD

CONTACT

+45 40460321; markrein@rm.dk

Henrik Birn, MD, DMSc

CONTACT

hb@clin.au.dk

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Target Duration: 10 Years
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 1, 2026
• First Posted: April 15, 2026
• Study Start: April 1, 2026
• Primary Completion (Estimated): March 31, 2031
• Study Completion (Estimated): March 31, 2031
• Last Updated: April 15, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

DK (3)