Early Recognition of Persistent Acute Kidney Injury
Section snippets
RENAL RECOVERY AND TIME TO RECOVERY: DEFINITIONS AND PROGNOSTIC IMPACT
The renal recovery epidemiology description is limited by significant heterogeneity in the available literature regarding the population studied, the definition used (RRT independency, decrease in one AKI severity stage, complete disappearance of AKI criteria, or return to baseline creatinine concentration) or the timing of its assessment (in the intensive care unit [ICU] or at hospital discharge, or at the 3-month time point required to diagnose chronic kidney disease [CKD]). In a recent large
URINARY INDICES
Historically, nonobstructive AKI related to mere hypoperfusion (prerenal AKI) and organic renal injury (intrinsic AKI) were differentiated and the ability of the tubule to concentrate urine was assessed.24, 25 This assessment was performed using urinary indices showing the ability of the tubule to reabsorb sodium and water (fractional excretion of sodium, natriuresis, fractional excretion of urea, urinary urea/creatinine ratio).24, 25 Most of these indices were validated in studies in which the
RENAL DOPPLER
Ultrasonography (US) is performed routinely to assess the morphology of kidneys, the collecting system, and the renal arteries and veins.37 Doppler-based renal resistive index (RI), the so-called Pourcelot index, and contrast-enhanced US (CEUS) are tools derived from Doppler to assess renal perfusion and predict AKI in ICU patients.38, 39
Renal RI measurement is rapid, easy to perform, and easy to learn. A half-day course on renal Doppler allowed inexperienced junior physicians to assess renal
PREDICTIVE MODELS
Only few predictive clinical models have been developed and tested specifically to assess the probability of renal recovery. None of them has been assessed and validated adequately.
The “renal angina index” was developed and validated to assess AKI risk at day 3, mainly in pediatric settings, and is the most studied model.65, 66 This score is the result of serum creatinine or fluid overload increase multiplied by contextual variables (organ or stem cell transplantation) or organ support.65, 66
BIOMARKERS
A biomarker is an indicator than can be quantified or evaluated objectively to indicate the status of a biological process or condition. Most AKI biomarkers are biochemical parameters that have been developed to detect early onset of AKI. However, their use has ranged from early AKI detection to assessment of chances of early renal recovery. Ideally, AKI biomarkers should have high sensitivity and specificity for kidney injury in the presence of concomitant injury involving other organs and
LIMITS OF CURRENT KNOWLEDGE
Most of the studies performed to date have been limited by imperfect definitions of renal recovery, various influences of the time chosen to define transient/persistent AKI, and gold standard. The threshold of the serum creatinine level to define recovery is likely to influence the rate of recovery, as is rate of approximate renal dysfunction or of unknown pre-existing renal dysfunction.20 Moreover, patients without available baseline serum creatinine concentrations differ significantly from
CONCLUSIONS
Although the definition of renal recovery has been standardized and its clinical relevancy has been shown, several uncertainties remain. First, the exact rate of recovery, accounting for competing risk, is unknown, as well as the optimal definition to conclude renal recovery. Moreover, although predicting short-term recovery might help in optimizing patient management and anticipate outcome, available imaging tests, biomarkers, and scores have not yet been validated and, at best, were found to
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Cited by (14)
Acute kidney injury in hospitalized patients with COVID-19: A Portuguese cohort
2021, NefrologiaCitation Excerpt :The impact of AKI duration on prognosis led to the development of a standardized definition of transient and persistent AKI, based on recovery of kidney function within 48 h, by the ADQI Workgroup.23 Transient AKI might reflect reversible renal impairment due to nephrotoxins or hemodynamic changes and persistent AKI is more likely a result of conditions less easily reversed and these patients may consequently require more RRT.46,47 Rubin et al. analyzed AKI in 77 critically ill patients with COVID-19 and demonstrated that persistent AKI was present in the majority of patients (93%).48
Sepsis-associated acute kidney injury: consensus report of the 28th Acute Disease Quality Initiative workgroup
2023, Nature Reviews NephrologyRenal scintigraphy to predict persistent renal failure after acute kidney injury: an observational study
2023, Journal of NephrologyMachine learning models for predicting acute kidney injury: a systematic review and critical appraisal
2022, Clinical Kidney JournalMissed diagnosis of acute kidney injury in older patients with invasive mechanical ventilation: a multicenter retrospective study
2022, Aging Clinical and Experimental Research
Financial support: none.
Conflict of interest statement: Michaël Darmon has received consulting fees from Sanofi and Gilead-Kite, research support from Astute Medical and MSD, and speaker fees from MSD, Gilead-Kite, and Astellas.