Aim To evaluate the utility of half systolic decay time (½SDT) of ductal flow measured by Doppler echocardiography in predicting PDA treatment in extremely premature babies.
Methods We prospectively recruited babies ≤30 weeks gestation. We performed serial echocardiograms (<48 hr of life [scan1], day 7 [scan2], week 2 [scan3], week 3 [scan4], week 4 [scan5]). In babies with PDA, we measured the time needed to halve peak systolic velocity (½SDT) across the duct using continuous wave Doppler. The clinical team was blinded to the research assessment.
Results A total of 48 babies were recruited to the study over a one-year period. Median gestational age was 26 weeks (range 23 -29) and mean birth weight (±SD) was 909g (±295). Seven babies (14%) were treated for PDA, including two needing surgical ligation. The ½SDT measured on scan2, was significantly shorter in the treated babies (p = 0.0172). In this study population ½SDT <90 ms measured on day 7 (scan2) was 100% specific in predicting need for PDA treatment. The parameter had a positive predictive value of 100% with sensitivity of 62.5%. The negative predictive value was 88% with diagnostic accuracy of 90%.
Conclusion In this population at our centre, all babies <30 weeks gestation with ½SDT <90 ms on day 7 of life were treated for PDA by clinicians blinded to this assessment. We believe that ½SDT warrants further investigation as an early marker for targeting PDA treatment in extremely preterm babies.