Biochemical markers of neonatal myocardial dysfunction

Abstract

Introduction. Cardiac ultrasounds (US) are not always available at the bedside. Cardiac Troponin I (cTnI), CK-MB and NT-proBNP may be an alternative or complementary to influence evaluation and treatment.

Objectives. To determine reference ranges of biochemical markers cTnI, CK-MB and NT-proBNP in normal neonates.

Methodology. Cord and blood samples were collected from neonates and the above biochemical markers were determined. Ultrasounds were performed blindly.

Results. CK-MB remains constant from cord blood to the first day, declining thereafter to almost half the values (81.5 vs 52.0 U/l); cTnI increases from 0.004 to 0.058 ng/ml by 72 h falling to 0.030 by day 10; NT-proBNP peaks by 24 h (5085.5 pg/ml), subsiding to 3388.5 pg/ml by day 3, falling to 1316.0 pg/ml by day 10.

Conclusions. CK-MB, mostly of muscle origin and reflecting labor stress or injury, is not to recommend as a measure of myocardial damage in the neonate. The rise in cTnI may be explained by a degree of myocardial involvement, albeit physiological. The initial rise and subsequent fall of NT-proBNP represents the physiological ventricular overload of transient birth adaptation.

Keywords:

• Cardiac biomarkers
• perinatal
• CK-MB
• cTnI
• NT-proBNP

Acknowledgements

The authors gratefully acknowledge the contribution to this work by the medical and nursing staff of the Obstetrics, Paediatrics/Neonatology Departments as well as the Clinical Pathology department of São Sebastião Hospital, Centro Hospitalar de Entre o Douro e Vouga.