Right ventricular systolic dysfunction in young adults born preterm

Abstract

Purpose: Young adults born preterm have increased left ventricular mass, reduced myocardial strain and a unique three-dimensional left ventricular geometry. We have now investigated whether preterm birth also has an impact on the right ventricle. Methods: We studied 102 preterm-born young adults followed prospectively since birth (mean gestational age = 30.3±2.5 weeks and mean birth weight = 1.30±0.29 kilograms) and 132 term-born controls born to uncomplicated pregnancies. We quantified right ventricular structure and function by cardiovascular magnetic resonance on a 1.5T Siemens scanner using Argus and TomTec 2D Cardiac Performance Analysis MR post-processing software. Results: Right ventricular mass was increased in the preterm-born young adults compared to term-born controls (24.5±3.5 vs. 20.4±3.4 g/m2, P<0.001) proportional to the changes in the left ventricle. The increase in mass was inversely related to gestational age (r=-0.47, P<0.001) with an incremental elevation in right ventricular mass for each increase in severity of prematurity (i.e. extremely preterm > very preterm > moderate to late preterm, P<0.05). Preterm-born young adults also showed a reduction in end-diastolic volume (79.8±13.2 vs. 88.5±11.8 mL/m2, P<0.001) and right ventricular free wall longitudinal peak systolic strain and longitudinal peak systolic strain rate compared to term-born controls (P<0.001). However, the changes in right ventricular function were more severe than observed for the left ventricle with a significant reduction in ejection fraction (57.0±7.6 vs. 60.0±5.3%, P=0.006), related to gestational age (r=0.46, P<0.001) and a proportion having ejection fractions below the normal range. Adjustment for postnatal ventilation accounted for some of this variation but an independent impact of prematurity remained. Conclusions: Young adults born preterm have increased right ventricular mass and significant reductions in right ventricular systolic function. These initial findings, in combination with our previous findings for the left ventricle, indicate myocardial changes in preterm infants are global and relevant to both pulmonary and systemic circulations. The changes are proportional to the degree of prematurity but may be more severe in the right ventricle.