Impact of surgical patent ductus arteriosus ligation before versus after 21 days of life on early postoperative blood pressure and short-term outcomes in very preterm infants

Patent ductus arteriosus (PDA) is common in very preterm infants, and surgical ligation may be considered when pharmacologic treatment is unsuccessful. However, the optimal timing of ligation remains uncertain, and its impact on early postoperative hemodynamic stability has not been systematically evaluated. This study aimed to investigate whether postnatal age at surgical ligation (≤ 21 days vs. >21 days) influences postoperative blood pressure profiles and short-term outcomes in preterm infants born at < 34 weeks’ gestation with hemodynamically significant PDA. A retrospective analysis was conducted of the clinical records of 67 inborn preterm infants born at < 34 weeks’ gestation who were admitted to and managed in our neonatal intensive care unit (Maternal and Child Health Hospital of Hubei Province) from November 2017 to April 2025, and who subsequently underwent surgical ligation for hemodynamically significant patent ductus arteriosus (hsPDA). Infants were stratified into an early-ligation group (≤ 21 days, n = 30) and a late-ligation group (> 21 days, n = 37). Propensity score overlap weighting was applied to balance baseline covariates. Blood-pressure trajectories within the first 72 h after ligation and the incidence of short-term preterm complications were compared between the two groups. After overlap weighting, baseline characteristics were well balanced between groups. Postoperative hypotension occurred more frequently in the early-ligation group than in the late-ligation group (27% vs. 16%; weighted RR 1.65, 95% CI 0.63–4.30), although the difference was not statistically significant. The peak occurrence was observed 6–12 h after ligation. In contrast, postoperative hypertension was more common in the late-ligation group (76% vs. 47%; weighted RR 0.62, 95% CI 0.39–0.97, P = 0.015), predominantly within the first 6 h. The early-ligation group demonstrated shorter total mechanical ventilation duration (P = 0.019), shorter hospitalization (P = 0.005), higher discharge weight (P = 0.001), greater daily weight gain (P < 0.001), and a lower incidence of severe bronchopulmonary dysplasia (7% vs. 32%, P = 0.033). No significant differences were observed in mortality, necrotizing enterocolitis, severe intraventricular hemorrhage, or retinopathy of prematurity. Timing of PDA ligation was associated with differences in postoperative blood pressure profiles: late ligation is associated with early hypertension, while early ligation shows a trend toward delayed hypotension. Early ligation (≤ 21 days) was associated with more favorable short-term respiratory and nutritional outcomes without increasing overall complications. These findings may inform individualized timing decisions and highlight the need for time-specific postoperative blood pressure monitoring strategies. Prospective randomized studies are warranted to confirm causality. Not applicable.