Xu ZR, et al. - In this prospective study involving consecutive patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI; n=146), researchers assessed the predictive value of the renal resistive index (RRI) for contrast-induced nephropathy (CIN). Pre-PCI and at 1 hour and 24 hours after PCI, RRI was measured by means of renal Doppler ultrasound examinations. Thirty-one patients developed CIN. At 1 hour and 24 hours post-procedure, they noted higher RRIs in patients with CIN vs those without. The pre-procedure RRI was identified as a powerful predictive indicator of CIN in a receiver operating characteristic curve analysis. With 67.7% sensitivity and 67% specificity, 0.69 was considered the best cutoff value. Findings revealed that, in patients with ACS undergoing PCI, a high pre-procedural RRI may be independently predictive of CIN.