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Updated: Jul 20, 2025
Hemodynamic Precision in the Neonatal Intensive Care Unit using Targeted Neonatal Echocardiography
Published on: January 27, 2023
Reproducibility of the EL-Khuffash PDA severity score and PDA diameter measurements in extremely preterm infants
Aisling Smith1, Rachel Mullaly1, Orla Franklin2
1Department of Neonatology, The Rotunda Hospital, Dublin, Ireland.
Insights
A new PDA Severity Score (PDAsc) shows superior reproducibility for assessing the significance of a Patent Ductus Arteriosus (PDA) compared to simple diameter measurements. This score is more reliable for clinical trial recruitment and treatment decisions in preterm infants.
Area of Science:
- Neonatal cardiology
- Pediatric echocardiography
- Clinical trial methodology
Background:
- Patent Ductus Arteriosus (PDA) is often assessed using a diameter ≥1.5 mm for haemodynamic significance in randomized controlled trials (RCTs).
- This criterion's reliability for clinical decision-making and trial recruitment is questioned.
- The need for a more reproducible method to assess PDA haemodynamic significance is evident.
Purpose of the Study:
- To evaluate the intra- and inter-rater reproducibility of a novel PDA Severity Score (PDAsc).
- To compare the reproducibility of PDAsc with the traditional PDA diameter measurement.
- To determine if PDAsc offers a more reliable criterion for assessing haemodynamic significance in preterm infants.
Main Methods:
- A cross-sectional study involving echocardiograms of 150 infants <30 weeks gestation.
- Calculation of PDA Severity Score (PDAsc) and measurement of PDA diameter.
- Blinded, repeated measurements by one investigator (intra-rater) and comparisons between two investigators (inter-rater) were performed.
Main Results:
- PDAsc demonstrated near-perfect agreement (Cohen's Kappa 0.97 intra-rater, 0.94 inter-rater) for treatment threshold (≥5.0).
- PDA diameter showed only moderate agreement (Kappa 0.57 intra-rater, 0.54 inter-rater).
- 31% of infants with low PDAsc (<5.0) had PDA diameter >1.5 mm, indicating potential discrepancies.
Conclusions:
- The PDA Severity Score (PDAsc) offers significantly superior intra- and inter-rater reproducibility compared to PDA diameter alone.
- PDAsc is a more reliable tool for assessing haemodynamic significance in preterm infants.
- Future RCTs should consider adopting PDAsc over isolated PDA diameter for patient recruitment.
Background & Aim:
Almost all randomised controlled trials use a Patent Ductus Arteriosus (PDA) diameter ≥ 1.5 mm as the primary criterion to ascribe haemodynamic significance to the PDA. The aim of this study was to evaluate if calculation of a PDA Severity Score (PDAsc) possessed superior intra- and inter-rater reproducibility when compared with the measurement of PDA diameter alone.
Methods:
This cross-sectional study assessed echocardiograms performed on infants <30 weeks gestation at 36 to 72 h of age between July 2020 and December 2022 to calculate the PDAsc. Intra-observer reproducibility of the PDA diameter and PDAsc were assessed by blinded repeated measurements performed by one investigator (AS) 4 weeks apart. One set of those measurements was compared with blinded measurements by another investigator (RM) to assess inter-rater reliability.
Results:
Echocardiograms from 150 infants with mean ± SD gestation and birthweights of 26.5 ± 1.7 weeks and 903 ± 249 g respectively were examined. The PDAsc demonstrated near perfect agreement both within raters (Cohen's Kappa 0.97, p < 0.01) and between raters (Cohen's Kappa 0.94, p < 0.01) with regards to the threshold for treatment (a cut off ≥5.0). The PDA diameter threshold only demonstrated moderate agreement within raters (Kappa 0.57, p < 0.01) and between raters (Kappa 0.54, p < 0.01). In this cohort, 31 % of infants with a low risk PDAsc (< 5.0) also had a PDA diameter >1.5 mm.
Conclusion:
Future RCTs for PDA treatment should strongly consider abandoning the use of PDA diameter in isolation as a criterion for recruitment into clinical trials.
