An observational study in End Stage Chronic Renal Failure, Renal Transplant and Microvascular Changes, sponsored by Roderick Tan. Not yet recruiting at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-06-12.
Sponsored by Roderick Tan · Observational
This pilot study is testing a new ultrasound imaging method called Super-Resolution Ultrasound (SRU) to look at blood flow and tiny blood vessels in transplanted kidneys in very detailed images after kidney transplant surgery. The goal is to see whether changes in the kidney's small blood vessels can help predict how well the transplanted kidney will work early after transplant, including whether delayed graft function may occur.
Investigators hope this technique can become a safe, noninvasive way to evaluate transplanted kidneys without needing as many invasive biopsies. It may also help doctors better assess donor kidneys at higher-risk of suboptimal functioning.
Specific Aim 1: Utilize super-resolution ultrasound (SRU) to analyze tiny blood vessels in transplanted kidneys under very detailed imaging and evaluate kidney allografts and predict post-transplantation function.
Delayed graft function (DGF) is a common complication that can happen soon after a kidney transplant and may lead to longer recovery times and other health problems. Kidney biopsies are typically required to find the cause, which are invasive procedures. Current imaging tests cannot clearly show the tiny blood vessel changes inside the transplanted kidney that may contribute to the development of DGF.
Hypothesis: Investigators hypothesize that SRU can noninvasively predict DGF outcomes by measuring changes in the structure of tiny kidney blood vessels and the blood flow within them.
Approach:
Aim 1a: Compare SRU-derived measures of renal microvasculature-including microvascular density, tortuosity, and cortical perfusion-between patients who develop DGF and those with uncomplicated graft function.
Aim 1b: Correlate SRU parameters with clinical outcomes at 30 and 90 days post-transplant, as determined from inpatient and outpatient data within the electronic medical record.
Experimental Plan. Allograft SRU will be performed in 20 renal allograft recipient patients up to 14 days after transplant (n=10 with DGF, n=10 without DGF). Patients will be identified and recruited from within UPMC. After injection with Definity, SRU images and measurements will be obtained as described elsewhere in this protocol. Measures are noninvasive, with the transducer applied to the body surface over the allograft. Measurements will be compared between the two groups, and correlations made with eGFR at 30 and 90 days, total days of dialysis, resistive indices, and interstitial fibrosis/tubular atrophy (IFTA) on the standard 3-month protocol biopsy.
Anticipated Results, Potential Pitfalls, and Future Directions. Investigators expect that renal blood volume and microvessel density will be higher in patients with functioning grafts, and that these parameters will be positively correlated with better outcomes, demonstrating that SRU is a promising and noninvasive prognostic tool.
Expected Outcomes and Impact: Investigators anticipate that SRU will identify microvascular densities predictive of DGF, providing a novel, noninvasive biomarker to guide post-transplant management. Successful completion of this aim will establish SRU as a clinically useful tool to reduce reliance on invasive biopsy and improve early allograft evaluation.
Specific Aim 2: Utilize super-resolution ultrasound (SRU) to evaluate early microvascular changes in high-KDPI kidneys up to 14 days after transplantation to predict early graft function.
Rationale: Donor kidneys with a high Kidney Donor Profile Index (KDPI) are often discarded due to their perceived risk of poor function, despite limited physiologic data on their microvascular integrity. Early post-transplant microvascular alterations may serve as critical indicators of graft viability and short-term function.
Hypothesis: Investigators hypothesize that SRU-detected microvascular changes occurring within the first 48 hours after transplantation can predict early transplanted kidney function and distinguish between high- and low-KDPI kidneys.
Experimental Plan:
Investigators will perform SRU imaging within 14 days of transplantation in kidney allograft recipients, using the same SRU parameters described in Aim 1. Investigators will compare SRU-derived measures such as structure, size, characteristics, and blood flow -between two groups: recipients of high-risk kidneys (KDPI >75; n = 10) and recipients of more optimal kidneys (KDPI \<35; n = 10). SRU findings will be correlated with key clinical outcomes, including the incidence of delayed graft function (DGF), need for dialysis, measures of kidney function at 30 and 90 day marks, and the degree of scarring of the functional units of the kidney observed on 90-day protocol biopsies.
Anticipated Results, Potential Pitfalls, and Future Directions:
Investigators anticipate that kidneys with higher KDPI values will demonstrate reduced vascular density and perfusion within 48 hours post-transplant, and that these findings will correlate with inferior 30- and 90-day outcomes. If no significant differences or correlations are observed, investigators will reconsider the utility of the 48-hour timepoint in future studies or examine whether recipient-specific factors (e.g., age, hemodynamic status, blood pressure) influence SRU measurements. Findings from this aim will inform whether SRU can serve as an early, noninvasive measurement of transplanted kidney quality and may challenge current allocation practices that exclude high-KDPI kidneys (high-risk of suboptimal functioning kidneys)
3,090 studies on the registry are indexed under Renal Insufficiency, Chronic; 698 are open to participants now.
This study's planned enrollment of 40 is below the median of 213 across 834 observational studies indexed under Renal Insufficiency, Chronic.
Browse Renal Insufficiency, Chronic studies →This is the only study on the registry with Roderick Tan as lead sponsor.
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Adult patients with end stage kidney disease who are receiving deceased donor kidney allograft transplants who meet the inclusion and exclusion criteria
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
For stage 1 of the study:
For stage 2 of the study
Exclusion Criteria:
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.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
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.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Adult end stage kidney disease patients who received a recent deceased donor kidney transplant with High KDPI allografts
Diagnostic Test: Ultrasound contrast agent (Contrast-enhanced ultrasound) · Drug: Optison (Perflutren Protein-Type A Microspheres Injectable Suspension) · Drug: Lumason® contrast agent · Drug: DEFINITY®
Adult end stage kidney disease patients who received a recent deceased donor kidney transplant with Low KDPI allografts
Diagnostic Test: Ultrasound contrast agent (Contrast-enhanced ultrasound) · Drug: Optison (Perflutren Protein-Type A Microspheres Injectable Suspension) · Drug: Lumason® contrast agent · Drug: DEFINITY®
Adult end stage kidney disease patients who received a recent deceased donor kidney transplant who require renal replacemen therapy within 2 weeks after transplant.
Diagnostic Test: Ultrasound contrast agent (Contrast-enhanced ultrasound) · Drug: Optison (Perflutren Protein-Type A Microspheres Injectable Suspension) · Drug: Lumason® contrast agent · Drug: DEFINITY®
Adult end stage kidney disease patients who received a recent deceased donor kidney transplant who do not require renal replacemen therapy within 2 weeks after transplant.
Diagnostic Test: Ultrasound contrast agent (Contrast-enhanced ultrasound) · Drug: Optison (Perflutren Protein-Type A Microspheres Injectable Suspension) · Drug: Lumason® contrast agent · Drug: DEFINITY®
Super-resolution ultrasound using lipid microsphere contrast
Approved drug or biologic being evaluated for a new indication, population, route of administration, or dosage level not specified in the FDA approved labeling for kidney imaging.
Approved drug or biologic being evaluated for a new indication, population, route of administration, or dosage level not specified in the FDA approved labeling for kidney imaging.
Approved drug or biologic being evaluated for a new indication, population, route of administration, or dosage level not specified in the FDA approved labeling for kidney imaging.
Kidney vascularity
Assessment of total renal vascularity and measures of perfusion. Images obtained with the kidney ultrasound will be analyzed for total number of blood vessels and blood perfusion detected in different regions of the kidney.
Time frame: Less than 30 minutes
Kidney blood vessel tortuosity
While the total number of blood vessels may differ between subjects, it is also possible that the number of blood vessel branches may be different.
Time frame: up to 30 minutes
Plan to share: Yes — Patient data such as demographics, test results, medical chart data, and data acquired from imaging including vessel density, cortical perfusion, and vessel branching.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form
Time frame: June 1, 2026 until June 30, 2030
Access criteria: Researchers with ideas for studies using our data may request it from the study PI.
This study is not yet recruiting, as verified in Jun 2026. You cannot join it, but the record below documents what was studied.
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Renal Insufficiency, Chronic →