Coronary flow in neonates with impaired intrauterine growth

Background: Subclinical myocardial injury has been reported in newborns with fetal weights < 2 SDs for gestational age. Intrauterine growth restriction might affect cardiac function and coronary flow (CF). Methods: Seventeen newborns with intrauterine growth restriction and 15 age-matched healthy controls were enrolled in the study. Blood flow in the umbilical artery and maternal uterine artery was assessed using Doppler velocimetry. Cardiac function and left anterior descending coronary artery CF were measured using transthoracic Doppler echocardiography at 1 week of age. Results: The mean growth deviation of the newborns from normal was -2.5 ± 0.2 SDs. Percentage left ventricular shortening fraction was 39 ± 4.3% in patients and 42 ± 4.1% in controls (P =.40), and the mean left ventricular mass index was 86.6 g/m ² in patients and 73.7 g/m ² in controls (P <.01). The mean left anterior descending coronary artery diameter was 0.99 ± 0.1 mm in patients and 0.8 ± 0.1 mm in controls (P =.002). The left anterior descending coronary artery flow velocity-time integral was correlated with left ventricular mass index (r = 0.31, P =.007) and with mitral peak E/A ratio (r = 0.74, P =.01). Intrauterine growth restriction was associated with increased peak flow velocity in diastole (34.5 ± 4 vs 19 ± 6 cm/sec in controls, P =.0001), as well as increased CF (37 ± 7.3 vs 8.2 ± 3.0 mL/min in controls, P =.001). Conclusions: CF is significantly increased in neonates with impaired intrauterine growth. Left ventricular mass index is increased, but systolic and diastolic function remains normal. The clinical significance of increased CF is unclear, but it might lead to decreased CF reserve.