Preterm Thrombocytopenia and Delay of Ductus Arteriosus Closure

Abstract

Objectives: To evaluate whether preterm thrombocytopenia within 24 hours of birth is associated with delayed closure of patent ductus arteriosus (PDA) and higher proportion of hemodynamically significant PDA (Hs-PDA).

Methods: Neonates (gestation 26^0/7-33^6/7 weeks, age <24 hours) with known platelet count and PDA on echocardiogram were prospectively enrolled. Asphyxia, congenital infections, structural heart disease, major malformations and clinical sepsis were exclusions. Subjects were recruited in groups A (n = 35), B (n = 18), and C (n = 17) [platelet counts >150,000, 100,000-150,000 and <100,000 per μL respectively] and underwent daily echocardiography until first closure of PDA, death, or day 10.

Results: The primary outcome was time to first closure of PDA. Secondary outcomes included proportion with PDA at 72 hours and 7 days, Hs-PDA, and PDA needing treatment. In groups A, B, and C, median (first-third quartile) platelet counts (×100000/μL) were 2.28 (1.94-3.19), 1.25 (1.14-1.37), and 0.68 (0.54-0.83) and time to PDA closure was 2 (2-2), 2 (2-3), and 10 (6-10) days, respectively (log-rank test, P < .001). On Cox proportional hazard regression, platelet count (in multiples of 10 000 /μL) independently predicted time to PDA closure (adjusted hazard ratio: 1.045; 95% confidence interval: 1.019-1.07). On day 7, 47.1% neonates in group C had PDA and none in groups A and B (P < .001).

Conclusions: Thrombocytopenia within 24 hours of birth independently predicts delayed PDA closure and PDA on day 7 in preterm neonates.