Effects of IUGR and prematurity on cardiac structure and function throughout infancy.

Background: Intra-uterine growth restriction (IUGR) alters cardiac structure and function, but how these changes develop throughout early life is unknown. Moreover, IUGR often leads to prematurity, which is an independent risk factor for cardiovascular disease. Studies disentangling the roles of IUGR and preterm birth are scarce. We aimed to investigate the effects of IUGR and prematurity on the structural and functional properties of the heart during early infancy. Method(s): Echocardiography was performed on 22 preterm IUGR infants and 20 preterm and 17 term appropriately-grownfor- gestational-age infants (pAGA, tAGA, respectively). Preterm infants were studied on postnatal day 1, and all groups were studied at 4 weeks and 6 months post-term age. Result(s): IUGR infants demonstrated increased cardiac sphericity compared to AGA peers on post-natal day 1 (IUGR 0.54 +/- 0.04 vs. pAGA 0.45 +/- 0.03, P<0.05) and at 4 weeks post-term age (IUGR 0.44 +/- 0.02 vs. pAGA 0.37 +/- 0.02 and tAGA 0.38 +/-0.01, P<0.05). Relative wall thickness increased over time in the IUGR group only (P<0.05). No differences were found in myocardial performance index, cardiac output and fractional shortening. E/E' ratio (reflecting diastolic dysfunction) was higher in the preterm groups than the term group at 4 weeks (IUGR 9.8 +/- 0.5 and pAGA 11.3 +/- 1.5 vs. tAGA 7.8 +/- 0.5, P<0.01) and 6months post-term age (IUGR 9.0 +/- 0.8 and pAGA 8.0 +/- 0.5 vs. tAGA 6.8 +/- 0.4, P<0.05). Conclusion(s): IUGR was associated with subtle cardiac structural changes, whereas prematurity was associated with subclinical alterations in diastolic function. These early changes observed within these populations may underpin their increased risk of cardiovascular disease later in life.