Preterm-born young adults exhibit greater extracellular volume fraction in left ventricle
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In a new study, young adults born preterm demonstrated increased extracellular volume fraction in the left ventricle compared with their term-born peers, which may underlie their diastolic functional impairments.
Adam J. Lewandowski, DPhil, of the University of Oxford, United Kingdom, told Healio that previous work by his group and others had demonstrated that the left ventricle has a unique structure and function that may put it at increased risk for CVD, including HF.
“Work in animal models of prematurity has shown that part of the observed functional impairment is driven by an increase in LV diffuse myocardial fibrosis, largely due to the increased stressors in early postnatal life associated with preterm birth,” Lewandowski said. “Interestingly, this greater diffuse myocardial fibrosis in the left ventricle is still present in adult animal models. We therefore conducted our study to test that hypothesis that human adults born preterm have greater LV diffuse myocardial fibrosis compared to their term-born peers, and to determine if this explains part of the known functional impairments observed in this population.”
The study included 101 normotensive young adults born preterm (n = 47; mean gestational age, 32.8 weeks) or at term (n = 54; mean gestational age, 39.5 weeks) from the YACHT study. Researchers used CV magnetic resonance and echocardiography to quantify LV structure and function.
Results revealed that adults born preterm had smaller LV end-diastolic and stroke volumes, and greater LV mass and wall thickness (P < .001). Longitudinal peak systolic strain and diastolic strain rate, as assessed by both CV magnetic resonance and echocardiography, and E/A ratio, as measured by echocardiography, were decreased in preterm-born compared with term-born adults (P < .05).
Furthermore, researchers found greater extracellular volume fraction in preterm-born compared with term-born adults (27.81% vs. 25.48%; P < .001), with volume fraction serving as a significant mediator in the relationship between gestational age and both longitudinal peak diastolic strain rate and E/A ratio.
Recognizing role of preterm birth ‘imperative’
As a result of the findings, Lewandowski said it is now clear that preterm birth is associated with an increased risk for CVDs, including hypertension, ischemic heart disease and HF.
“Subclinical diseases, including high blood pressure and mild cardiac dysfunction, are detectable in young adulthood, and thus, recognition of preterm birth as a significant risk factor for cardiovascular disease becomes imperative for clinicians, parents and the preterm-born adults,” he said. “Birth history should be included in best practice guidelines from childhood to adulthood to permit healthy lifestyle counseling and appropriate screening, which may include performing blood pressure measurements, an EKG and an echocardiogram, as well as exercise testing to distinguish between cardiac and pulmonary limitations.”
Directions for future research
In an accompanying editorial, Tal Geva, MD, with Boston Children’s Hospital, and Emily M. Bucholz, MD, PhD, MPH, with Harvard Medical School, wrote that this study adds to the growing literature examining preterm birth and subsequent adverse CV outcomes, and commended the work as a detailed demonstration of the potential mechanistic link between prematurity and cardiac remodeling.
“These observations highlight the importance of future large prospective longitudinal studies from birth into adulthood designed to understand the influence of the prenatal environment, the timing of cardiac remodeling and the prognostic value of these imaging biomarkers. Greater insight into the pathogenesis and clinical implications of the cardiac changes seen after preterm birth may help to risk stratify patients and better mitigate the long-term effects of prematurity,” they wrote.
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For more information:
Adam J. Lewandowski, DPhil, can be reached at adam.lewandowski@cardiov.ox.ac.uk; Twitter: @drajlewandowski.
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