| Premature birth, defined as birth prior to 37 weeks gestation, affects 10% of live births in the United States. Advances in neonatal care have resulted in the increased survival of infants born at extremely low gestational ages. Infants born preterm are at higher risk of developing pulmonary arterial hypertension that can ultimately lead to right ventricular (RV) dysfunction with subsequent RV failure. However, little is known about the long-term impact of preterm birth on the RV and pulmonary vasculature.;Our goal is to determine the long-term effects of prematurity on RV and pulmonary vascular function and hemodynamics.;Preterm subjects (n = 11) were recruited from the Newborn Lung Project, with very low birth weight (≤ 1500g; average gestational age 28 weeks) between 1988 and 1991. Control subjects from the same birth years (n = 10) were recruited from the general population. Right heart catheterization was performed to assess RV and pulmonary vascular hemodynamics at rest and during exercise in normoxia and hypoxia. Magnetic resonance imaging was performed to determine RV function at rest.;We found that preterm subjects had higher mean pulmonary arterial pressures (mPAP), with 36% meeting criteria for borderline pulmonary. (RV) afterload was higher at rest among preterm subjects. During exercise, preterm subjects had higher total pulmonary vascular resistance and lower compliance, and demonstrated less ability to augment stroke volume (SV). Utilization of two physiological stressors (hypoxia and hypoxic exercise) unmasked altered RV function in preterm subjects. When looking at the percent change from rest to hypoxic exercise, preterm subjects exhibited an attenuated mPAP, sRVP, CI,SV index and HR response compared to age matched controls suggesting that the RV is inappropriately compensating for the demand during hypoxic exercise. RV end-diastolic volume, SVI and ejection fraction were significantly lower in preterm subjects. Preterm subjects had higher global RV strain compared to controls. However, RV-PV coupling was lower in preterm subjects compared to controls suggesting they have a less efficient RV. Taken together, Young adults born preterm demonstrate early pulmonary vascular disease, and altered right ventricular function suggesting an increased risk to develop overt pulmonary hypertension and right heart failure. |
