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Early Postnatal Changes in Left Heart Dimensions in Infants Undergoing Neonatal Repair of Coarctation of the Aorta
R Carnall1,2, S Chivers3, S Polyviou4
1Department of Congenital Heart Disease, Evelina London Children's Hospital, London, UK. Rachel.carnall@nhs.net.
Insights
Early hemodynamic changes after birth significantly impact left heart size in infants with suspected coarctation of the aorta. Those with smaller initial heart dimensions showed the greatest growth postnatally.
Area of Science:
- Pediatric Cardiology
- Neonatal Physiology
- Congenital Heart Disease
Background:
- The transition from fetal to neonatal circulation involves significant hemodynamic shifts.
- Increased left ventricular preload and afterload can affect left heart development in neonates.
- Coarctation of the aorta presents unique challenges to postnatal cardiovascular adaptation.
Purpose of the Study:
- To investigate the impact of early postnatal hemodynamic changes on left heart size and Z-scores in infants with suspected coarctation of the aorta.
- To analyze serial echocardiographic data to quantify changes in cardiac dimensions.
- To determine if initial left heart dimensions influence the magnitude of postnatal growth.
Main Methods:
- Retrospective study of 51 infants with prenatally suspected coarctation of the aorta repaired before 30 days of age.
- Sequential echocardiography performed at three time points: <48h (US1), 48h-7 days (US2), and >7 days (US3).
- Assessment of cardiac dimensions and calculation of Z-scores for left heart structures.
Main Results:
- Significant increases in Z-scores from US1 to US3 for left ventricular length, aortic valve, and distal transverse aortic arch.
- Paired analysis (US1 vs. US2) revealed significant increases in Z-scores for left ventricular length, aortic valve, and mitral valve.
- Changes in dimensions and Z-scores were inversely correlated with initial Z-scores; smaller initial sizes showed greater increases.
Conclusions:
- Infants with suspected coarctation of the aorta exhibit significant postnatal changes in left heart structure dimensions and Z-scores.
- The degree of postnatal cardiac growth is influenced by initial cardiac dimensions, with smaller hearts growing more.
- These findings highlight the dynamic nature of cardiac adaptation in neonates with coarctation of the aorta.
Abstract:
The transition from prenatal to postnatal life involves major changes in cardiac loading conditions, including increased left ventricular preload and afterload, potentially affecting left heart size during the neonatal period. We hypothesized that early postnatal hemodynamic changes would significantly impact left heart size and derived Z-scores. We report serial data from infants with prenatally suspected coarctation of the aorta who underwent coarctation repair. We retrospectively studied 51 infants with a prenatal diagnosis of suspected coarctation of the aorta who underwent repair before 30 days of age. Sequential echocardiography was performed at less than 48 h (US1), 48 h to seven days (US2) and over seven days or last pre-operative scan (US3). Cardiac dimensions were assessed on two-dimensional ultrasound and Z-scores computed. Across US1, US2, and US3 groups, significant median Z-score increases from US1 to US3 were observed for LV length (1.3), AoV (1.0), and DTAA (Distal transverse aortic arch) (0.6). Paired data (US1 vs. US2) showed significant increases in LV length Z-score (0.3), AoV Z-score (0.7), and mitral valve Z-score (1.0). Changes in dimensions and Z-scores inversely correlated with initial Z-scores, meaning infants with the smallest initial left heart dimensions exhibited the largest increases. Infants with prenatally suspected coarctation of the aorta demonstrate postnatal changes in absolute measurements and Z-scores of left heart structures. The infants with the smallest initial size of left heart structures showed the greatest increase in size during the neonatal period.
