ORIGINAL ARTICLE

Use of low molecular mass heparin (enoxaparin) in newborn infants: a prospective cohort study of 62 patients

W Streif¹, G Goebel², A K C Chan³, M P Massicotte⁴

¹ Department of Pediatrics, University of Innsbruck, Austria
² Department of Biostatistics and Documentation, University of Innsbruck
³ Department of Pediatrics, McMaster University, Hamilton, Canada
⁴ The Hospital for Sick Children, Toronto, Canada

Correspondence to:
Correspondence to:
Dr Streif, Department of Pediatrics, University of Innsbruck, 6020 Innsbruck, Austria;
Werner.Streif{at}uibk.ac.at

Objective: To detail low molecular mass heparin (enoxaparin) use in the first few months of life.

Design: Prospective, consecutive cohort of unselected newborn infants.

Methods: Newborn infants were divided into groups by gestational age, underlying condition, hepatic and renal function, thrombocytopenia, and prothrombin time (PT/INR). Groups were analysed with respect to many aspects of enoxaparin treatment using multivariate methods.

Results: Sixty two newborn infants received enoxaparin representing 5.39 treatment years. Thromboembolic events (TEs) occurred predominantly in the lower and upper venous system in the presence of indwelling catheters (69%). Preterm infants required longer than full term infants to achieve an anti-(factor Xa) level in the target range (six versus two days). Preterm infants required higher doses of enoxaparin than full term infants to maintain anti-(factor Xa) levels in the target range (2.1 v 1.7 mg/kg/12 h). Infants with congenital heart disease (CHD) required less enoxaparin than those without CHD to maintain an anti-(factor Xa) level in the target range (1.7 v 2.1 mg/kg/12 h). Impaired renal and liver function influenced the number of dose changes needed (three versus one a month). Complete or partial resolution of TE was accomplished in 59% of newborn infants. Four infants developed major bleeds (1.2% per patient year). Recurrent TE and clot extension occurred in three infants (0.9% per patient year).

Conclusions: Preterm infants are more difficult to treat with enoxaparin than full term infants. Enoxaparin appears to be an alternative to treatment with standard heparin or no treatment.

Keywords: thrombosis; thromboembolism; low molecular mass heparin; enoxaparin

Abbreviations: CHD, congenital heart disease; HSC, The Hospital For Sick Children, Toronto, Canada; INR, international normalised ratio; LMMH, low molecular mass heparin; TE, thromboembolic event; US, ultrasonography

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• Gohil, J. R, Solanki, D. I, Vaghjiyani, L. (2009). Low molecular weight heparin (enoxaparin) reverses pregangrene in a preterm neonate. BMJ Case Reports 2009: bcr1220081388-bcr1220081388 [Abstract] [Full Text]  
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