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NCT Number: NCT07017933

Groundbreaking Renal Assist Device Intervening to ENhance cardioThoracic Surgery Outcomes

Patients with renal insufficiency who undergo cardiac surgery with cardiopulmonary bypass (CPB) are at significant risk for exacerbation of renal dysfunction postoperatively. This in turn is associated with an increased risk of prolonged intensive care unit (ICU) length of stay, other comorbidities including surgical complications and 30-day mortality. Renal impairment is generally identified based on an increase in serum creatinine concentration and/or a certain magnitude decrease in estimated glomerular filtration rate (eGFR).

The JuxtaFlow® Renal Assist Device (RAD) is designed to sustain or enhance glomerular filtration perioperatively for patients with renal insufficiency by applying a mild controlled negative pressure to the collecting system via the renal pelvis, thereby increasing effective filtration pressure and reducing tubular pressure. This mechanism is designed to support the kidneys' functions during times of renal stress that would be associated with intrarenal edema, volume overload, increased venous pressure, and inflammatory response. By supporting renal function, specifically during the acute stress of CPB, JuxtaFlow holds promise to protect nephron function, decrease renal hypoxia, and provide multifactorial kidney function support to maintain their ability to manage future stress.

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Key information

Conditions

Renal Impairment After Cardiac Surgery Acute Kidney Injury Female Urogenital Diseases Female Urogenital Diseases and Pregnancy Complications Kidney Diseases Male Urogenital Diseases Renal Impairment Renal Insufficiency Urogenital Diseases Urologic Diseases

Age range

22 year–85 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

American Heart of Poland, Bielsko-Biala, Poland

Loading trial locations.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

To be eligible for participation in this study, an individual must meet all the following criteria:

  • A candidate for elective or urgent on-pump coronary artery bypass grafting (CABG) and/or valvular surgery
  • Male or Female age 22 to 85 years
  • Estimated glomerular filtration rate (eGFR) 15 - 60 mL/min/1.73m2
  • Signed and dated informed consent
  • Female patients of childbearing potential must:
  • have negative pregnancy test at the informed consent visit,
  • be using previously initiated approved and effective contraception from the informed consent visit through completion of the study *The only recommended contraception is condoms.

Exclusion criteria

An individual who meets any of the following criteria will be excluded from participation in this study:

  • Any individual, or their legally authorized representative (LAR), who does not understand the requests and risks of participating in the clinical trial or is unable to give informed consent
  • Pregnancy or lactation
  • Prior cardiac surgery within the last 6 months
  • Hemodynamic instability as determined by the Principal Investigator
  • Immunosuppression
  • Active infections (e.g. HIV, Tbc, and all types of Hepatitis)
  • History of polycystic kidney disease
  • Patients with only one active kidney or one poorly functioning kidney
  • Evidence of current kidney obstruction (e.g., Kidney stones)
  • Evidence of current hydronephrosis
  • Active upper and/or lower urinary tract infections
  • Malignancy; oncological Surgery within 5 years or ongoing antitumoral treatment
  • Ongoing sepsis or endocarditis
  • Patients who have an expected 30-day postoperative mortality greater than 10% as determined by the Principal Investigator
  • Any secondary condition as determined by the investigator that would place the subject at an increased risk or preclude the subject's full compliance with the study procedures, including injuries to the urinary organs and/or external genitals; or severe BPH
  • Unexplained/unexpected gross hematuria as determined by the Investigator
  • Current or planned treatment with an investigational drug (IND), device (IDE), or other investigational intervention within 3 months prior to or during participation in this clinical trial
  • Patients who have a current unrepaired ureteral avulsion as determined by the investigator
  • Patients otherwise contraindicated for urological interventions, including ureter guidewire placement via bladder cystoscopy and ureteral catheterization, or otherwise contraindicated for any of the other study procedures

Treatment and study plan

Renal assist device

Device

The JuxtaFlow RAD includes two endoscopically placed ureteral catheters connected to a bedside pump system. The catheters are designed to deliver a mild, controlled negative pressure (-15 mmHg ± 2mmHg) into the renal pelvis of each kidney for up to 72 hours. This pressure is designed to diffuse through each of the million nephrons lowering intratubular pressure thereby improving the filtration gradient at the glomerulus while supporting overall kidney function.

Other names: RAD, JuxtaFlow

Primary outcomes

  1. Mean Peak Percent Change in Serum Creatinine

    Time frame: 96 hours peri-operative

    The mean peak percent change in serum creatinine from baseline values (prior to treatment) within the first 96 hours post-surgery for JuxtaFlow treated subjects as compared to controls.

  2. Incidence of Treatment-Emergent Adverse Events

    Time frame: From enrollment to post-operative day 30

    The characterization and comparison of all types, frequency, and severity of adverse events (AEs) associated with JuxtaFlow treatment and controls.

Secondary outcomes

  1. AUC Serum Creatinine

    Time frame: 96 hours peri-operative

    The area under the curve of serum creatinine changes from baseline values (prior to treatment) up to 96 hours post-surgery for JuxtaFlow treated subjects as compared to controls.

  2. Creatinine Clearance

    Time frame: 24 to 48 hours post-operatively

    The average creatinine clearance as a measure of acute glomerular filtration rate, assessed for a minimum of 24 and up to 48 hours in 8-hour intervals during postoperative ICU JuxtaFlow treatment as compared to controls.

  3. AKI incidence

    Time frame: From post-operative day 1 to 14

    The incidence of acute kidney injury (as determined by the KDIGO criteria) during post-surgical hospitalization and 14 days post-surgery with treatment as compared to controls.

  4. Critical Care Length of Stay

    Time frame: through study study completion, an average of 1 year

    The post-surgical critical care length of stay (LOS) in the United States cohort for JuxtaFlow treated subjects as compared to controls.

Other outcomes

  1. AKI severity

    Time frame: From post-operative day 1 to 14

    The severity and duration of acute kidney injury (as determined by the KDIGO criteria) during post-surgical hospitalization and 14 days post- surgery with treatment as compared to controls.

  2. Urine Electrolytes

    Time frame: Up to 72 hours peri-operatively

    The change in urine sodium and potassium excretion rates during the treatment period (up to 72 hours) as compared to controls. Urine output will be assessed in 8-hour intervals perioperatively.

  3. eGFR

    Time frame: From enrollment to post-operative day 30

    The change in eGFR (measured by 2021 EPI Cr method) measured at baseline, perioperatively, and at 14- and 30-days post-surgery in JuxtaFlow treated subjects as compared to controls.

  4. Urine Output

    Time frame: Up to 72 hours peri-operatively

    The change in urine output (i.e. volume, urine flow, total oliguria time, total anuria time, etc.) over the course of treatment (up to 72 hours) as compared to controls. Urine output will be assessed in 8-hour intervals perioperatively.

  5. Hospital Length of Stay

    Time frame: through study study completion, an average of 1 year

    The post-surgical hospital length of stay (LOS) in the United States cohort for JuxtaFlow treated subjects as compared to controls.

  6. Anemia Incidence

    Time frame: through study study completion, an average of 1 year

    The incidence of anemia (as defined by a nadir hematocrit below 23% for women and 28% for men after initiating the investigational treatment) assessed immediately after starting treatment, immediately after surgery, and at every postoperative 8-hour period during treatment (up to 72-hours) after initiation of the treatment, and daily during the post-treatment period (until hospital discharge) as compared to controls.

  7. Electrolyte abnormalities

    Time frame: through study study completion, an average of 1 year

    The incidence of electrolyte abnormalities (as defined by any alteration in the metabolic panel according to the reference values after initiating the investigational treatment) assessed immediately after starting JuxtaFlow treatment, immediately after surgery, and at every postoperative 8-hour period during treatment (up to 72-hours) after initiation of the investigational treatment, and daily during the post-treatment period (until hospital discharge). Assessed by comprehensive metabolic panel (includes calcium, sodium, potassium and carbon dioxide) and excretion rates calculated from a Urinalysis panel (includes sodium and potassium).

  8. Azotemia

    Time frame: through study study completion, an average of 1 year

    The incidence of azotemia or elevated blood urea nitrogen (BUN).

  9. Dialysis Incidence

    Time frame: From post-operative day 1 to 30

    The incidence of dialysis within 30 days post-surgery.

  10. Hospital Readmission

    Time frame: From post-operative day 1 to 30

    Readmission to in-patient hospitalization for any reason within the 30- day postoperative period.

  11. Mortality

    Time frame: From post-operative day 1 to 30

    All-cause mortality at 30 days post-surgery.

Study contacts

Contact information is provided by the study sponsor or research team.

Alencia Washington, PhD

CONTACT

[email protected]

Allison Fenderson, RN, MSHS, CCRP

CONTACT

[email protected]

919-744-5703

Sponsors and collaborators

Lead sponsor

3ive Labs

Industry

Collaborators

  • Fortrea

Registry information

Acronym: GRADIENT

Important dates

Study start
2025
Primary completion
2026
Study completion
2027
First posted
Jun 12, 2025
Registry last updated
Mar 19, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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