Akut Kidney InjuryNCT06995222
The Role of Renal Resistive Index (RI) in Predicting Acute Kidney Injury Progression in Intensive Care Clinic
An observational study of Akut Kidney Injury and Renal Replacement Therapy for Acute Kidney Injury in ICU, run by Gulhane Training and Research Hospital at 1 site in Turkey (Türkiye).
Trial summary
Acute kidney injury(AKI) is defined in the KDIGO guidelines as a ≥0.3 mg/dL (≥26.5 micromol/L) increase in serum creatinine in the previous 48 hours or a ≥1.5-fold increase in serum creatinine from baseline, known or presumed to have occurred in the previous seven days, or a urine volume <0.5 mL/kg/hour for six hours. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Akut Kidney Injury, Renal Replacement Therapy for Acute Kidney Injury in ICU
- What is being tested?
- renal resistive index with Doppler ultrasound
- How many people
- 120 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 Jan 2025to 1 Jul 2026
- How long will I take part?
- 28 Days
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Male and female patients over 18 years of age who met KDIGO ABH stage 1 or stage 2 criteria and were hemodynamically stable in the first 24 hours of admission to the Internal Medicine Intensive Care Unit of Gülhane Training and Research Hospital, University of Health Sciences.
Who may be able to join
- Being over 18 years of age
- Having KDIGO stage 1 or stage 2 acute kidney injury within the first 24 hours of admission
Who cannot join
- 1. Patients who did not provide a consent form for participation in the study 2. Patients under 18 years of age 3. Pregnant women 4. Patients with postrenal acute kidney injury 5. Patients 24 hours after the diagnosis of acute kidney injury 6. Patients with acute kidney injury in the recovery period 7. Patients who were evaluated as KDIGO ABH stage 3 during hospitalization 8. Patients with a known history of renal artery stenosis 9. Patients with a diagnosis of cardiac arrhythmia 10. Patients with a diagnosis of chronic kidney disease and a glomerular filtration rate below 30 ml/min/1.73m2 11. Patients with intra-abdominal pressure above 20 mmHg 12. Patients with a hospitalization period of less than 24 hours
Trial locations and contacts
1 site in 1 country.
Turkey (Türkiye)1 site
Gulhane Education and Research Hospital Ankara Türkiye
Ankara, Türkiye, 06010
About this study
Official title: The Role of Renal Resistive Index (RI) in Predicting Acute Kidney Injury Progression and Need for Renal Replacement Therapy in Patients Followed in the Intensive Care Clinic
Acute kidney injury(AKI) is defined in the KDIGO guidelines as a ≥0.3 mg/dL (≥26.5 micromol/L) increase in serum creatinine in the previous 48 hours or a ≥1.5-fold increase in serum creatinine from baseline, known or presumed to have occurred in the previous seven days, or a urine volume <0.5 mL/kg/hour for six hours.
Given the high morbidity and mortality associated with AKI, many investigators are studying several novel biomarkers to detect AKI progression earlier, identify etiologies and predict outcomes. However, the utilisation of these novel biomarkers may be constrained by reimbursement considerations.
Read more
The renal resistive index (RRI) is a well-established metric for evaluating renal perfusion; however, its application in the context of AKI has been a subject of recent debate. While RRI has been utilised to demonstrate perfusion in acute and chronic renal diseases, particularly in conjunction with ultrasonography, its efficacy remains a subject of scientific discourse. In addition, Boddi reported that RRI is a strong indicator of mortality and a diagnostic marker, especially in patients with persistent AKI.
The present study aims to evaluate the appropriateness of using the RRI, a non-invasive procedure, to determine the progression of AKI stages and the need for renal replacement therapy in patients hospitalised in intensive care units.
Read the detailed description
Acute kidney injury(AKI) KDIGO guidelines for AKI include an increase in serum creatinine of ≥0.3 mg/dL (≥26.5 micromol/L) in the last 48 hours or an increase in serum creatinine of ≥1 mg/dL (≥26.5 micromol/L) from baseline, known or presumed to have occurred in the previous seven days, 5-fold increase or urine volume <0.5 mL/kg/hour for six hours.
The incidence of in-hospital AKI varies between 7. 0-18.3% in hospitalized patients in general and up to 20-50% in critically ill patient populations . In addition to causing a high mortality and morbidity, especially in critically ill patients, AKI prolongs the duration of hospitalization in the intensive care unit.
Due to the high morbidity and mortality associated with AKI, many researchers have been studying several novel biomarkers for earlier detection of AKI progression, identification of etiologies and prediction of outcomes. However, the use of these new biomarkers may be limited by reimbursement issues.
Although renal resistive index(RRI) shows intraparenchymal perfusion of the kidney, RRI is used to show perfusion in acute and chronic diseases of the renal parenchyma, especially as a result of the widespread use of ultrasonography(USG) in recent times. In addition, Boddi reported that RRI is a strong indicator of mortality and a diagnostic marker, especially in patients with persistent AKI. Many studies have shown that RRI is a promising marker for early detection of renal injury. Patients who develop AKI often require renal replacement therapy (RRT), but there is generally no consensus on the optimal timing of the initiation of RRT. RRT is an invasive procedure. The desired outcome in patients with AKI is normalization of renal function without invasive intervention. However, a more conservative approach to initiating RRT in the course of AKI may expose the patient to adverse outcomes. Therefore, designing a marker that predicts the likelihood of a more severe AKI progression would help us to better make decisions regarding the optimal timing of RRT initiation.
In this study, we aimed to evaluate the appropriateness of using the RRI, a noninvasive procedure, to detect progression in AKI stages and the need for RRT in intensive care unit patients.
- Being tested
- renal resistive index with Doppler ultrasound
- Keywords
- akut kidney injury, renal resistive index, renal replacement therapy, intensive care
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
renal resistive index with Doppler ultrasoundDiagnostic test
Renal resistive index uses doppler ultrasonography which assesses blood flow velocity in the renal arteries. The Renal Resistive Index (RI) is calculated by substracting diastolic velocity from systolic velocity then dividing result by systolic velocity
Where:
Systolic velocity is the peak velocity of the blood flow during the systolic phase of the cardiac cycle.
Diastolic velocity is the velocity of blood flow during the diastolic phase.
What is being measured
The primary outcome is the main question the study is designed to answer.
Akut kidney injury progression
Patients admitted to our intensive care clinic with a diagnosis of AKI stage 1-2(according to KDIGO staging) will have RI measurement with Doppler Ulsanography within the first 24 hours of admission. Patients will be followed up daily from the time of measurement until the end of the study period and their progression to AKI stage 3(according to KDIGO staging) will be recorded. Patients will be monitored throughout the study. A comparison will be made between the groups that developed AKI stage 3(according to KDIGO staging) and those that did not develop AKI stage 3 during the study.
Measured: 14 days
Secondary outcomes (4)
14th day mortality rate
The mortality status of patients on the 14th day after ICU admission will be recorded. The relationship between RI value and 14-day mortality will be evaluated.
Measured: 14 days
28th day mortality rate
The mortality status of patients on the 28th day after ICU admission will be recorded. The relationship between RI value and 28-day mortality will be evaluated.
Measured: 28 days
Length of stay in the intensive care unit
The duration of stay in the ICU will be recorded for each patient. The association between RI value and length of ICU stay will be assessed.
Measured: 18 months
Need for renal replacement therapy (RRT)
The requirement for RRT during ICU stay will be recorded according to KDIGO criteria. Patients who require RRT will be compared with those who do not, in terms of RI level.
Measured: 14 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 May 2025
- Study start1 Jan 2025
- Primary completion1 Jul 2026
- Study completion1 Jul 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Akut Kidney InjuryStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 120 participants (actual)
- Target duration
- 28 Days
Sponsor and investigators
- Lead sponsor
- Gulhane Training and Research Hospital
- Sponsor type
- Other government
- Responsible party
- Principal investigator, Mete Erdemir, Gulhane Training and Research Hospital
- Investigators
- Gürhan T associate professor doctor, Study director, Gulhane Education and Research Hospital Ankara Türkiye
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06995222
- Sponsor's protocol ID
- 2025-07
- Status last verified
- Apr 2025
- First submitted
- 4 Apr 2025
- Last updated
- 5 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: research results will be published and the data used in the publication will be available for sharing upon request
Publications
Gibney N, Hoste E, Burdmann EA, Bunchman T, Kher V, Viswanathan R, Mehta RL, Ronco C. Timing of initiation and discontinuation of renal replacement therapy in AKI: unanswered key questions. Clin J Am Soc Nephrol. 2008 May;3(3):876-80. doi: 10.2215/CJN.04871107. Epub 2008 Mar 5.
PubMed 18322044
Study at a glance
From the registry record, last updated by the sponsor on 5 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Role of Renal Resistive Index (RI) in Predicting Acute Kidney Injury Progression and Need for Renal Replacement Therapy in Patients Followed in the Intensive Care Clinic
- ClinicalTrials.gov ID
- NCT06995222
- Acronym / sponsor ID
- 2025-07
- Keywords
- akut kidney injury, renal resistive index, renal replacement therapy, intensive care
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 120 participants (actual)
- Lead sponsor
- Gulhane Training and Research HospitalOther government
- Study start
- 1 Jan 2025 (actual)
- Primary completion
- 1 Jul 2026 (actual)
- Study completion
- 1 Jul 2026 (actual)
- First posted
- 29 May 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Acute kidney injury(AKI) is defined in the KDIGO guidelines as a ≥0.3 mg/dL (≥26.5 micromol/L) increase in serum creatinine in the previous 48 hours or a ≥1.5-fold increase in serum creatinine from baseline, known or presumed to have occurred in the previous seven days, or a urine volume <0.5 mL/kg/hour for six hours.
Given the high morbidity and mortality associated with AKI, many investigators are studying several novel biomarkers to detect AKI progression earlier, identify etiologies and predict outcomes. However, the utilisation of these novel biomarkers may be constrained by reimbursement considerations.
The renal resistive index (RRI) is a well-established metric for evaluating renal perfusion; however, its application in the context of AKI has been a subject of recent debate. While RRI has been utilised to demonstrate perfusion in acute and chronic renal diseases, particularly in conjunction with ultrasonography, its efficacy remains a subject of scientific discourse. In addition, Boddi reported that RRI is a strong indicator of mortality and a diagnostic marker, especially in patients with persistent AKI.
The present study aims to evaluate the appropriateness of using the RRI, a non-invasive procedure, to determine the progression of AKI stages and the need for renal replacement therapy in patients hospitalised in intensive care units.
Detailed description
Acute kidney injury(AKI) KDIGO guidelines for AKI include an increase in serum creatinine of ≥0.3 mg/dL (≥26.5 micromol/L) in the last 48 hours or an increase in serum creatinine of ≥1 mg/dL (≥26.5 micromol/L) from baseline, known or presumed to have occurred in the previous seven days, 5-fold increase or urine volume <0.5 mL/kg/hour for six hours.
The incidence of in-hospital AKI varies between 7. 0-18.3% in hospitalized patients in general and up to 20-50% in critically ill patient populations . In addition to causing a high mortality and morbidity, especially in critically ill patients, AKI prolongs the duration of hospitalization in the intensive care unit.
Due to the high morbidity and mortality associated with AKI, many researchers have been studying several novel biomarkers for earlier detection of AKI progression, identification of etiologies and prediction of outcomes. However, the use of these new biomarkers may be limited by reimbursement issues.
Although renal resistive index(RRI) shows intraparenchymal perfusion of the kidney, RRI is used to show perfusion in acute and chronic diseases of the renal parenchyma, especially as a result of the widespread use of ultrasonography(USG) in recent times. In addition, Boddi reported that RRI is a strong indicator of mortality and a diagnostic marker, especially in patients with persistent AKI. Many studies have shown that RRI is a promising marker for early detection of renal injury. Patients who develop AKI often require renal replacement therapy (RRT), but there is generally no consensus on the optimal timing of the initiation of RRT. RRT is an invasive procedure. The desired outcome in patients with AKI is normalization of renal function without invasive intervention. However, a more conservative approach to initiating RRT in the course of AKI may expose the patient to adverse outcomes. Therefore, designing a marker that predicts the likelihood of a more severe AKI progression would help us to better make decisions regarding the optimal timing of RRT initiation.
In this study, we aimed to evaluate the appropriateness of using the RRI, a noninvasive procedure, to detect progression in AKI stages and the need for RRT in intensive care unit patients.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Target follow-up
- 28 Days
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Male and female patients over 18 years of age who met KDIGO ABH stage 1 or stage 2 criteria and were hemodynamically stable in the first 24 hours of admission to the Internal Medicine Intensive Care Unit of Gülhane Training and Research Hospital, University of Health Sciences.
Key inclusion criteria (2 listed)
- Being over 18 years of age
- Having KDIGO stage 1 or stage 2 acute kidney injury within the first 24 hours of admission
Key exclusion criteria (1 listed)
- 1. Patients who did not provide a consent form for participation in the study 2. Patients under 18 years of age 3. Pregnant women 4. Patients with postrenal acute kidney injury 5. Patients 24 hours after the diagnosis of acute kidney injury 6. Patients with acute kidney injury in the recovery period 7. Patients who were evaluated as KDIGO ABH stage 3 during hospitalization 8. Patients with a known history of renal artery stenosis 9. Patients with a diagnosis of cardiac arrhythmia 10. Patients with a diagnosis of chronic kidney disease and a glomerular filtration rate below 30 ml/min/1.73m2 11. Patients with intra-abdominal pressure above 20 mmHg 12. Patients with a hospitalization period of less than 24 hours
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| renal resistive index with Doppler ultrasoundRenal resistive index uses doppler ultrasonography which assesses blood flow velocity in the renal arteries. The Renal Resistive Index (RI) is calculated by substracting diastolic velocity from systolic velocity then dividing result by systolic velocity Where: Systolic velocity is the peak velocity of the blood flow during the systolic phase of the cardiac cycle. Diastolic velocity is the velocity of blood flow during the diastolic phase. | Diagnostic test | – |
Primary outcome
Akut kidney injury progression
Time frame: 14 days
Patients admitted to our intensive care clinic with a diagnosis of AKI stage 1-2(according to KDIGO staging) will have RI measurement with Doppler Ulsanography within the first 24 hours of admission. Patients will be followed up daily from the time of measurement until the end of the study period and their progression to AKI stage 3(according to KDIGO staging) will be recorded. Patients will be monitored throughout the study. A comparison will be made between the groups that developed AKI stage 3(according to KDIGO staging) and those that did not develop AKI stage 3 during the study.
4 secondary outcomes
14th day mortality rate
Time frame: 14 days
28th day mortality rate
Time frame: 28 days
Length of stay in the intensive care unit
Time frame: 18 months
Need for renal replacement therapy (RRT)
Time frame: 14 days
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Aug 2026.
- Background: PubMed 18322044Gibney N, Hoste E, Burdmann EA, Bunchman T, Kher V, Viswanathan R, Mehta RL, Ronco C. Timing of initiation and discontinuation of renal replacement therapy in AKI: unanswered key questions. Clin J Am Soc Nephrol. 2008 May;3(3):876-80. doi: 10.2215/CJN.04871107. Epub 2008 Mar 5.
- Individual participant dataSharing planned: Yes. research results will be published and the data used in the publication will be available for sharing upon request
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Gürhan T associate professor doctor study director
Gulhane Education and Research Hospital Ankara Türkiye
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Akut Kidney Injury and Renal Replacement Therapy for Acute Kidney Injury in ICU, run by Gulhane Training and Research Hospital at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 5 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Akut kidney injury progression (time frame: 14 days). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06995222, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Aug 2026.