Background Cardiac Troponin-T (cTNT) has been proposed as a useful marker of PDA-severity in preterm infants. Longitudinal-data on cTNT in extremely preterm infants is scarce.

Methods We included 60 infants born before 28 weeks of gestation at the Karolinska University Hospital in Stockholm Sweden and measured cTnT at 3 days (range 2–4) and 7 days (range 5–9) of age. Fourty-two infants had cTNT measured at two weeks of life (range 11–18 days). Wilcoxon signed rank-test was used to test for differences in cTnT between the different time-points.

Results Mean gestational age was 26.1 weeks (range 23.0–27.9) and mean birth weight 838 g (438–1287 g). At postnatal day 3, median cTnT was 148 ng/l (range 82–386). cTnT decreased between day 3 and day 7 to 96 ng/l (68–214) (p < 0.001). Between one and two weeks of age, cTnT again increased to 144 ng/l (95–338) (p = 0.001). Thirty-four infants (57%) were treated for a hemodynamically significant PDA (hsPDA) at a mean age of 8 days (SD 3.3). Twenty-three received only pharmacological treatment, 9 had surgery after pharmacological treatment and 2 had primary surgery. cTNT did not differ at any of the three time points between infants treated for hsPDA and infants not treated. Five infants who later died had significantly higher cTnT at 7 days of age than the 55 survivors (median 175 ng/l, compared to 94 ng/l) (p = 0.01).

Conclusion cTnT levels in extremely preterm infants are tenfold higher than reference values in adults. We did not find any relation between cTnT and need for PDA-treatment in this study.