Platelet Count and Volume and Pharmacological Closure with Paracetamol of Ductus Arteriosus in Preterm Infants.

Background: Low platelet count might promote resistance to pharmacological closure with indomethacin and ibuprofen of a hemodynamically significant patent ductus arteriosus (hsPDA). However, no studies have investigated if this occurs with paracetamol. Methods: We retrospectively assessed the correlation between platelet count, mean platelet volume (MPV), and plateletcrit (PCT), as well as the effectiveness of paracetamol in closing hsPDA in infants born at 23+0-31+6 weeks of gestation who were treated with 15 mg/kg/6 h of i.v. paracetamol for 3 days. Results: We studied 79 infants: 37 (47%) Had closure after a course of paracetamol and 42 (53%) did not. Platelet count and PCT did not correlate with paracetamol success or failure in closing hsPDA, while MPV was lower at birth (10.7 ± 1.4 vs. 9.5 ± 1.1; p < 0.001) and prior to starting therapy (11.7 ± 1.9 vs. 11.0 ± 1.6; p = 0.079) in refractory infants. Regression analysis confirmed that the low MVP measured prior to starting the treatment increased the risk of hsPDA paracetamol closure failure (OR 1.664, 95% CI 1.153-2.401). Conclusions: The greater MPV correlated positively with the effectiveness of paracetamol in closing hsPDA, while platelet count and PCT did not influence closure rates. Additional studies are needed to confirm our results.