Doppler-based renal resistive index for prediction of renal dysfunction reversibility: A systematic review and meta-analysis

Background and objectivesDoppler-based renal resistive index (RI) might help in distinguishing transient from persistent acute kidney injury (AKI). The main objective of these systematic review and meta-analysis was to investigate the diagnostic performance of RI in predicting short-term reversibility of AKI.Study designA systematic review of the literature was performed. Relevant studies were identified in Pubmed and Cochrane databases covering the years 1985 to 2013 and reviewed independently by 3 authors. Renal transplant recipients were excluded from this analysis.The summary estimates were computed using a random-effects model based on the DerSimonian and Lair meta-analytic method.ResultsAmong the 154 unique articles identified, 9 studies were included. Of the 176 patients in these studies with elevated RI or pulsatility index, 146 (83%) had a persistent AKI vs 44 (16%) of the 273 patients with normal values. Elevated RI or pulsatility index was associated with an increased risk of persistent AKI (odds ratio, 29.85; 95% confidence interval [CI], 8.73-102.16; P < .00001) with significant heterogeneity (I2 = 75.0%, P < .0001). The pooled sensitivity and specificity were 0.83 (95% CI, 0.77-0.88) and 0.84 (95% CI, 0.79-0.88). The summary positive and negative likelihood ratios were 4.9 (95% CI, 2.44-9.87) and 0.21 (95% CI, 0.11-0.41).ConclusionThese results suggest that an elevated RI may be a predictor of persistent AKI in critically ill patients. Further studies are warranted, however, to clarify the exact test performance given the marked heterogeneity among the included studies.