OBJECTIVE: To prospectively study the diagnostic usefulness of altered renal waveforms in patent ductus arteriosus. METHODS: We studied preterm infants undergoing echocardiography for a suspected patent ductus arteriosus. A spectral Doppler display was acquired for both renal arteries, and a resistive index was obtained. Sensitivity, specificity, and likelihood ratios were calculated using a clinically significant patent ductus arteriosus (>1.5-mm diameter on color Doppler ultrasonography) as the standard of reference. RESULTS: Fifty infants had 78 scans. A significant patent ductus arteriosus was present on 39 scans. When the renal resistive index was greater than 1.0, the likelihood ratio for a significant patent ductus arteriosus was 24.8 (specificity, 97.2%; SD, 3.8%). When the renal resistive index was 1.0 or less, the likelihood ratio for a significant patent ductus arteriosus was 0.2 (sensitivity, 77.2%; SD, 9.4%). CONCLUSIONS: Renal resistive index measurement is a simple investigation that can predict a significant patent ductus arteriosus in patients without congenital heart disease or other causes of diastolic runoff when echocardiography is unavailable.
OBJECTIVE: To prospectively study the diagnostic usefulness of altered renal waveforms in patent ductus arteriosus. METHODS: We studied preterm infants undergoing echocardiography for a suspected patent ductus arteriosus. A spectral Doppler display was acquired for both renal arteries, and a resistive index was obtained. Sensitivity, specificity, and likelihood ratios were calculated using a clinically significant patent ductus arteriosus (>1.5-mm diameter on color Doppler ultrasonography) as the standard of reference. RESULTS: Fifty infants had 78 scans. A significant patent ductus arteriosus was present on 39 scans. When the renal resistive index was greater than 1.0, the likelihood ratio for a significant patent ductus arteriosus was 24.8 (specificity, 97.2%; SD, 3.8%). When the renal resistive index was 1.0 or less, the likelihood ratio for a significant patent ductus arteriosus was 0.2 (sensitivity, 77.2%; SD, 9.4%). CONCLUSIONS: Renal resistive index measurement is a simple investigation that can predict a significant patent ductus arteriosus in patients without congenital heart disease or other causes of diastolic runoff when echocardiography is unavailable.