Does Early Neonatal Thrombocytopenia Affect Ductal Therapeutic Response to Acetaminophen in Preterm Neonates?

Abstract

Perinatal thrombocytopenia has been shown to affect responsiveness to therapeutic ductal closure with cyclo-oxygenase inhibitors. This has not been studied in responsiveness to acetaminophen, which has less effect on platelet function. Objective: To evaluate whether thrombocytopenia affects ductal responsiveness to acetaminophen. Study Design: Retrospective review of preterm neonates <1500 gm. Echocardiograms were performed within the first week of life; if ductal status was found to be hemodynamically significant, infants were treated with acetaminophen. Results: We studied 254 infants. Fifty seven of these (22%) had a hemodynamically significant PDA (hsPDA) and were treated with acetaminophen. Forty (70%) of those treated responded with ductal closure after 1-2 courses of acetaminophen. Seventeen infants were considered non-responsive, requiring the addition of ibuprofen and/or surgical ligation. Sixty-seven of the 254 infants (26%) developed moderate thrombocytopenia [platelets <100,000] within the first ten days of life, more within the hsPDA group (54% vs. 18% p<0.001); however, no differences in platelet related parameters were observed when comparing infants with hsPDA who did or did not respond to acetaminophen treatment. Twenty-six of the 67 thrombocytopenic were already thrombocytopenic prior to acetaminophen treatment; and 19 of these 26 (73%) with pre-treatment thrombocytopenia responded to acetaminophen treatment – similar to the overall response rate of 70% . Conclusions: This study is the first to document that, in contrast to the cyclo-oxygenase inhibitors, there is no association between early neonatal thrombocytopenia and ductal therapeutic responsiveness to acetaminophen.