Abstract
IntroductionExperimental and clinical studies show that prematurity leads to altered right ventricular (RV) performance with potentially clinically significant impairments in RV systolic function in young adulthood.HypothesisWe hypothesized that reductions in RV function would be out of proportion to changes in pulmonary physiology.MethodsWe recruited 101 normotensive young adults born preterm (n=47, mean gestational age 32.8±3.2 weeks) and term (n=54, mean gestational age 39.5±1.4 weeks) for detailed cardiovascular phenotyping. The gestational age range for the preterm cohort was 23 to 36 weeks, with 80.9% (n=38) born 32-36 weeks; 10.6% (n=5) born 28-31 weeks; and 8.5% (n=4) born <28weeks. Resting echocardiograms were performed to characterize RV morphology, RV function, and pulmonary hemodynamics, and spirometry was performed to assess lung function.ResultsPreterm-born individuals had smaller RV end-diastolic (p<0.001) and end-systolic areas (p=0.035) and inferior RV lengths (p=0.001) compared to term-born individuals. Measures of RV function, RV fractional area of change (FAC) and tricuspid annular plane systolic excursion (TAPSE) were lower in preterm compared to term-born young adults (FAC38.2±9.75 vs 43.8±7.01%, p=0.009 and TAPSE1.77±0.26 vs 2.24±0.37 cm, p<0.001). Pulmonary artery acceleration time (PAAT), a reliable estimate of pulmonary hemodynamics, was lower in the preterm-born young adults (PAAT123.4±23.8 vs 159.0±23.2 msec, p<0.001), though there were no differences between groups in estimated RV-pulmonary vascular (PV) coupling (TAPSE/PAAT0.15±0.02 vs 0.14±0.03 m/sec, p=0.77). Percentage predicted lung function measures were similar between those born preterm and termforced expiratory volume in 1 second (FEV1, p=0.41); forced vital capacity (FVC, p=0.88); and FEV1/FVC ratio (p=0.84). Lower RV FAC and TAPSE in preterm-born individuals remained significant when adjusting for pulmonary function parameters (p<0.05).ConclusionsPreterm-born young adults have reduced RV function, independent of lung physiology. RV afterload is increased, but the RV remains hemodynamically coupled to its pulmonary circulation despite worse RV function and altered morphology in young adults born preterm.