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NCT Number: NCT07821983

Renal Doppler Indices for Predicting Acute Kidney Injury After Isolated CABG

Acute kidney injury can occur after coronary artery bypass grafting (CABG). This prospective, single-center observational study will evaluate whether two measurements obtained from renal Doppler ultrasound-the renal augmented velocity index (AVI) and renal resistive index (RRI)-can help predict postoperative acute kidney injury. About 200 adults undergoing elective isolated CABG with cardiopulmonary bypass will have bilateral renal Doppler examinations one day before surgery, within 60 minutes after admission to the intensive care unit, and 6 hours after intensive care unit admission. The primary outcome is acute kidney injury within the first 7 days after surgery, defined according to Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Ultrasound measurements will be analyzed offline and will not influence clinical care.

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Key information

Conditions

Acute Kidney Injury Arterial Occlusive Diseases Arteriosclerosis Cardiovascular Diseases Coronary Artery Disease Coronary Disease Female Urogenital Diseases Female Urogenital Diseases and Pregnancy Complications Heart Diseases Kidney Diseases Male Urogenital Diseases Myocardial Ischemia Renal Insufficiency Urogenital Diseases Urologic Diseases Vascular Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Bursa Yuksek Ihtisas Training and Research Hospital

Bursa, Turkey (Türkiye)

Location contact

Nuri Burkay Soylu, MD

CONTACT

[email protected]

+90 538 248 4728

Nuri Burkay Soylu, MD

PRINCIPAL_INVESTIGATOR

About this study

This is an academic, prospective observational cohort study at Bursa Yuksek Ihtisas Training and Research Hospital. Adults scheduled for elective isolated on-pump CABG who provide informed consent will be enrolled consecutively.

Bilateral renal Doppler waveforms will be obtained at three time points: T0, one day before surgery after at least 10 minutes of rest; T1, within the first 60 minutes after postoperative intensive care unit admission; and T2, 6 hours after intensive care unit admission. AVI and RRI will be calculated from stored waveforms by investigators blinded to clinical outcomes. No treatment decisions will be based on these study measurements. No additional blood or urine samples will be collected for research, and no biospecimens will be retained.

The primary analysis will assess the association and predictive performance of perioperative AVI and RRI measurements for KDIGO-defined acute kidney injury within 7 postoperative days. Secondary analyses will evaluate severe acute kidney injury, renal replacement therapy, mechanical ventilation duration, intensive care unit and hospital length of stay, major postoperative complications, 30-day mortality, renal function and renal recovery at day 30, and perioperative changes in AVI and RRI.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Age 18 years or older.
  • Scheduled for elective isolated coronary artery bypass grafting with cardiopulmonary bypass (on-pump).
  • Able and willing to provide written informed consent.
  • Both kidneys present.
  • Adequate bilateral preoperative renal Doppler signal for study measurements.

Exclusion criteria

  • Preoperative chronic dialysis or renal replacement therapy.
  • Urgent or emergency surgery.
  • Combined cardiac surgery, including valve, aortic, or another major additional procedure.
  • Off-pump coronary artery bypass grafting or conversion of the planned surgical technique.
  • Clinically significant rhythm disturbance preventing acquisition of three interpretable cardiac cycles.
  • Renal transplant, solitary kidney, significant renal artery stenosis, previous renal artery intervention, hydronephrosis, or other relevant renal vascular or structural disease.
  • Inadequate bilateral preoperative renal Doppler examination.
  • Withdrawal of consent.

Treatment and study plan

Renal Doppler Ultrasonography

Diagnostic Test

Bilateral renal Doppler examinations are performed at T0 (one day before surgery after at least 10 minutes of rest), T1 (within the first 60 minutes after postoperative ICU admission), and T2 (6 hours after ICU admission). Renal augmented velocity index and renal resistive index are calculated offline from stored waveforms. Study measurements do not guide clinical care.

Other names: Renal Doppler Ultrasound

Primary outcomes

  1. Incidence of Acute Kidney Injury According to KDIGO Criteria

    Time frame: From surgery through postoperative day 7

    Number and percentage of participants who develop acute kidney injury according to Kidney Disease: Improving Global Outcomes (KDIGO) criteria, based on serum creatinine and/or urine output.

Secondary outcomes

  1. Incidence of KDIGO Stage 2 or 3 Acute Kidney Injury

    Time frame: From surgery through postoperative day 7

    Number and percentage of participants who develop KDIGO stage 2 or 3 acute kidney injury based on serum creatinine and/or urine output criteria.

  2. Need for Renal Replacement Therapy

    Time frame: During the index hospitalization, up to 30 days after surgery

    Number and percentage of participants who require postoperative renal replacement therapy.

  3. Duration of Mechanical Ventilation

    Time frame: During the index hospitalization, up to 30 days after surgery

    Duration of invasive mechanical ventilation, measured in hours from postoperative intensive care unit admission until successful extubation.

  4. Intensive Care Unit Length of Stay

    Time frame: During the index hospitalization, up to 30 days after surgery

    Duration of postoperative intensive care unit stay, measured in days from intensive care unit admission to intensive care unit discharge.

  5. Hospital Length of Stay

    Time frame: During the index hospitalization, up to 30 days after surgery

    Duration of the index hospital stay, measured in days from surgery to hospital discharge.

  6. Incidence of Major Postoperative Complications

    Time frame: During the index hospitalization, up to 30 days after surgery

    Number and percentage of participants with one or more major postoperative complications, including low cardiac output syndrome, perioperative myocardial infarction, new atrial fibrillation or serious arrhythmia, stroke or transient ischemic attack, reoperation for bleeding, sepsis or serious infection, prolonged vasopressor requirement, or mechanical circulatory support.

  7. All-Cause Mortality

    Time frame: Through 30 days after surgery

    Number and percentage of participants who die from any cause within 30 days after surgery.

  8. Renal Function and Renal Recovery at Day 30

    Time frame: 30 days after surgery

    Serum creatinine and estimated glomerular filtration rate at day 30 will be compared with preoperative baseline values to assess renal recovery.

  9. Change in Renal Doppler Indices

    Time frame: From one day before surgery through 6 hours after intensive care unit admission

    Change in renal augmented velocity index and renal resistive index from the preoperative T0 measurement to T1 and T2 postoperative measurements.

Study contacts

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

Nuri Burkay Soylu, MD

CONTACT

[email protected]

+90 538 248 4728

Sponsors and collaborators

Lead sponsor

Bursa Yuksek Ihtisas Training and Research Hospital

Other Gov

Registry information

Official study title

Role of Renal Augmented Velocity Index and Resistive Index in Predicting Postoperative Acute Kidney Injury After Isolated Coronary Artery Bypass Grafting

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Sep 16, 2026
Registry last updated
Sep 16, 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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