Relapse of patent ductus arteriosus (PDA) in extremely low-birth-weight infants (ELBW, ≤ 750g) remains a problem with significant morbidity. PDA relapse in larger preterm infants has been variably correlated with echocardiographic (Echo) PDA diameter, peak flow velocity (Vmax), and peak pressure gradient (PGrad) across the PDA. We studied Echo determinants of relapsed PDA from among ELBW infants in a blinded, randomized controlled trial of prophylactic indomethacin (BW 500-1249g, surfactant treatment, placebo vs. indomethacin 0.2, 0.1, 0.1 mg/kg @ time 0, 12, 36 hrs begun on day 1). From this cohort, 79 ELBW infants were identified; of the 56 surviving≥ 72 hrs, 17 had a pre-treatment Echo (#1, day 1) and 42 had a post-treatment Echo (#2, day 3-5) from which diameter, Vmax, and calculated PGrad were compared between infants who ultimately had relapse of a previously closed PDA vs those without. Pre-treatment PDA diameter was 42% larger on day 1 in infants destined to relapse; no difference was observed on day 3-5 (see table). Vmax and Pgrad in both time periods tended to be lower in infants with PDA relapse; also, infants who had pulmonary hemorrhage as a complication of PDA tended to have lower Vmax (Echo#1: 85±49 vs 116±41, #2: 98±39 vs 125±52, both NS) and PGrad (#1: 4.0±4.0 vs 6.1±4.9, #2: 4.4±3.6 vs 7.6±6.3, both NS). These data support the hypothesis that elevated pulmonary vascular pressure contributes to both PDA and pulmonary hemorrhage. We conclude that early Echo features of the ductus arteriosus may be useful in predicting ELBW infants destined for PDA relapse and PDA complications.

Table 1
Full size table