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.
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.
Study Type
OBSERVATIONAL
Enrollment
200
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.
Bursa Yuksek Ihtisas Training and Research Hospital
Bursa, Bursa, Turkey (Türkiye)
Incidence of Acute Kidney Injury According to KDIGO Criteria
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.
Time frame: From surgery through postoperative day 7
Incidence of KDIGO Stage 2 or 3 Acute Kidney Injury
Number and percentage of participants who develop KDIGO stage 2 or 3 acute kidney injury based on serum creatinine and/or urine output criteria.
Time frame: From surgery through postoperative day 7
Need for Renal Replacement Therapy
Number and percentage of participants who require postoperative renal replacement therapy.
Time frame: During the index hospitalization, up to 30 days after surgery
Duration of Mechanical Ventilation
Duration of invasive mechanical ventilation, measured in hours from postoperative intensive care unit admission until successful extubation.
Time frame: During the index hospitalization, up to 30 days after surgery
Intensive Care Unit Length of Stay
Duration of postoperative intensive care unit stay, measured in days from intensive care unit admission to intensive care unit discharge.
Time frame: During the index hospitalization, up to 30 days after surgery
Hospital Length of Stay
Duration of the index hospital stay, measured in days from surgery to hospital discharge.
Time frame: During the index hospitalization, up to 30 days after surgery
Incidence of Major Postoperative Complications
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.
Time frame: During the index hospitalization, up to 30 days after surgery
All-Cause Mortality
Number and percentage of participants who die from any cause within 30 days after surgery.
Time frame: Through 30 days after surgery
Renal Function and Renal Recovery at Day 30
Serum creatinine and estimated glomerular filtration rate at day 30 will be compared with preoperative baseline values to assess renal recovery.
Time frame: 30 days after surgery
Change in Renal Doppler Indices
Change in renal augmented velocity index and renal resistive index from the preoperative T0 measurement to T1 and T2 postoperative measurements.
Time frame: From one day before surgery through 6 hours after intensive care unit admission
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