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Updated: Aug 20, 2025
In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography
Published on: February 16, 2016
Myocardial perfusion and function dichotomy in growth restricted preterm infants
Arvind Sehgal1,2, Beth J Allison3,4, Suzanne L Miller3,4
1Monash Newborn, Monash Children's Hospital, Clayton, Victoria, Australia.
Insights
Preterm infants with fetal growth restriction (FGR) show increased coronary artery blood flow (CABF) but impaired cardiac function postnatally. This suggests fetal programming or altered cardiac structure, not improved heart health, in FGR infants.
Area of Science:
- Neonatal cardiology
- Fetal medicine
- Pediatric cardiovascular research
Background:
- Fetal growth restriction (FGR) is associated with altered fetal circulation.
- Postnatal cardiovascular adaptation in FGR infants remains poorly understood.
- Previous studies suggest dichotomy between coronary artery blood flow (CABF) and cardiac function in utero.
Purpose of the Study:
- To compare postnatal coronary artery blood flow (CABF) and cardiac function in preterm FGR infants versus appropriate for gestational age (AGA) infants.
- To investigate the relationship between CABF and cardiac function in the early postnatal period.
- To explore potential mechanisms underlying observed cardiovascular differences in FGR.
Main Methods:
- Prospective comparative study of preterm FGR and AGA infants.
- Defined FGR by birthweight <10th centile and absent/reversed umbilical artery Doppler.
- Assessed diastolic CABF and cardiac function (systolic and diastolic) via echocardiography in the second week of life.
Main Results:
- FGR infants exhibited significantly higher CABF (velocity time integral) compared to AGA infants.
- Impaired diastolic function (increased trans-mitral E/A ratio) and affected systolic function (reduced mean velocity of circumferential fibre shortening) were observed in FGR infants.
- Despite higher CABF, FGR infants showed poorer cardiac function indices when CABF was indexed to cardiac function parameters.
Conclusions:
- Increased postnatal CABF in preterm FGR infants does not correlate with improved cardiac function.
- The observed cardiovascular dichotomy may represent a persistent response to fetal hypoxemia (fetal programming).
- Altered cardiac architecture in FGR infants could also contribute to the observed functional differences.
Abstract:
Compared to preterm appropriate for gestational age (AGA) fetuses, fetuses with fetal growth restriction (FGR) have earlier visualisation of coronary artery blood flow (CABF) but impaired cardiac function. This dichotomy remains uncharacterised during postnatal life. This study compared CABF and cardiac function in preterm FGR infants, against AGA infants during the postnatal period. FGR was defined as birthweight < 10th centile for gestation and sex with absent/reversed antenatal umbilical artery Doppler. Diastolic CABF was measured in the left anterior descending coronary artery. Twenty-eight FGR infants were compared with 26 AGA infants (gestation and birthweight, 29.7 ± 1.3 vs 29.9 ± 1 weeks, P = 0.6 and 918 ± 174 vs 1398 ± 263g, P < 0.001, respectively). Echocardiography was performed in the second week of life. FGR infants had higher CABF (velocity time integral, 2.4 ± 0.9 vs 1.6 ± 0.8 cm, P = 0.002). Diastolic function was impaired (↑ trans-mitral E/A ratio in FGR infants; 0.84 ± 0.05 vs 0.79 ± 0.03, P = 0.0002) while the systolic function was also affected (mean velocity of circumferential fibre shortening [mVCFc], 1.9 ± 0.3 vs 2.7 ± 0.5 circ/s, P < 0.001). Indexing CABF to cardiac function noted significant differences between the groups (CABF: E/A [FGR vs AGA], 2.9 ± 1.1 vs 2.1 ± 1, P = 0.01 and CABF: mVCFc [FGR vs AGA], 1.3 ± 0.5 vs 0.6 ± 0.3, P < 0.001). Diastolic blood pressure (BP) was significantly higher, and CABF to diastolic BP ratio trended higher in FGR infants (30 ± 2 vs 25 ± 3 mmHg, P < 0.001 and 0.08 ± 0.03 vs 0.06 ± 0.03, P = 0.059, respectively). Greater CABF in FGR infants did not translate into better cardiac function. This dichotomy may be a persistent response to fetal hypoxaemia (fetal programming) and/or reflection of altered cardiac architecture.
