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Abstract

in the study by de Freitas et al was the timing of targeted neonatal echocardiography (ie, between days 7 and 30 of life), because the decision when to treat a hemodynamically relevant PDA must usually be taken much earlier. 1 Although we did perform serial echocardiography in the first week of life and thereafter, it must also be stated that our study identified other important nonhemodynamic parameters that were at play with regard to the occurrence of AKI. 2 We conclude that it is important to collect data on both the size of the PDA with correction for birth weight, possibly birth length, and its effect on flow patterns in the cerebral, mesenteric/ celiac, and renal arteries. In doing so, an individualized approach can be realized to determine whether subsequent therapeutic interventions (eg, use of cyclo-oxygenase inhibitors or surgery) are warranted for PDA closure. 3 We agree with de Freitas et al that isolated parameters (ductal diameter) should not be used as a surrogate indicator of the magnitude of shunt volume to inform treatment decisions. 1 We also suggest that the findings gathered at the bedside may be complemented by the use of biomarkers (brain natriuretic peptide and N-terminal pro-brain natriuretic peptide) for the assessment of the significance of PDA. 4 Finally, it is important to correlate clinical findings (bounding pulses, wide pulse pressure, increase in oxygen requirements, oliguria, and feeding intolerance) with these important, repetitively performed echocardiographic parameters, to assess changes over time. 3 When putting all these information pieces together, the assessment of a PDA with regard to its hemodynamic relevance may become less puzzling.

Relationship of Patent Ductus Arteriosus Echocardiographic Markers With Descending Aorta Diastolic Flow

“…1,9 In addition, direct measurement of the ductal diameter has several limitations: First, the vessel is variable in architecture, shape, and vascular responsiveness and therefore has an unpredictable response to treatment. 6,8 Second, operator-dependent factors may influence diagnostic accuracy; for example, poorquality 2D images or excessive color Doppler gain 1,14 may lead to errors in the estimation of the transductal diameter. Third, the acquisition of high-quality PDA images sometimes can be difficult because of lung hyperinflation.…”

“…Therefore, the PDA diameter alone is unlikely to represent the magnitude of physiologic complexity 1,9 . In addition, direct measurement of the ductal diameter has several limitations: First, the vessel is variable in architecture, shape, and vascular responsiveness and therefore has an unpredictable response to treatment 6,8 . Second, operator‐dependent factors may influence diagnostic accuracy; for example, poor‐quality 2D images or excessive color Doppler gain 1,14 may lead to errors in the estimation of the transductal diameter.…”

“…3,4 Although echocardiography is the reference standard diagnostic method for a PDA, accurate and direct measurement of the transductal shunt volume is not possible because of the variance in ductal morphologic characteristics and the coexistence of transatrial shunts. 5,6 An indirect appraisal of the PDA shunt volume, based on echocardiographic markers of left heart overload and systemic hypoperfusion, is commonly used; these measurements, however, have not been validated with true estimates of the shunt volume. [7][8][9][10] We recently reported that the ductal diameter correlates poorly with echocardiographic estimates of the shunt volume.…”