The use of renal Doppler ultrasonography to diagnose patent ductus arteriosus in preterm infants.

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.