A002 Very Low Birth Weight is Associated With Reduced Right Ventricular Function Detected by Strain Imaging in Early Adulthood – Findings From a Prospective Cohort Study

Abstract

Those born at very low birth weight (VLBW, <1500g) have increased rates of cardiopulmonary disorders in childhood. As survivors age, late cardiac effects are emerging. Echocardiographic strain imaging provides prognostically important information regarding the right ventricle (RV) in diverse cardiopulmonary conditions but has not been described in VLBW cohorts. We assessed right heart function using strain in young adults born at VLBW, compared to normal-weight term-born controls. The NZ Very Low Birth Weight Study has followed all infants born in 1986 with birth weight <1500g. Of 323 survivors to adulthood, 229 (71%) had echocardiograms at 26-30 years which were compared to age -matched term-born, normal-weight controls (n=100). RV global longitudinal strain (GLS) was measured. Established echo measures of RV function including fractional area change (FAC), tricuspid annular systolic velocity (RV S') and tricuspid regurgitation velocities (TR) were also measured. VLBW subjects were smaller than their peers as young adults (BSA 1.85+/-0.3m2 vs 1.96+/-0.9m2). Strain measurement showed reduced myocardial deformation among VLBW subjects (n=106) compared to controls (n=60): RV myocardial GLS: -22.4%(+/-2.3) vs -23.5%(+/-2.9), p=0.008; RV endocardial GLS: -23.6%(+/-2.7) vs -24.9%(+/-3.2), p=0.005; free wall myocardial GLS: -25.2% (+/-2.9) vs-26.1% (+/-2.7), p=0.039; free wall endocardial GLS: -26.7%(+/-2.9) vs -27.9% (+/-3.1), p=0.009). TR velocity was higher in VLBW: 2.2m/s vs 2.1m/s (p=0.006). RV S' (12.5cm/s vs 12.9cm/s) and FAC: 42.5% vs 43.7% were not different. Young adults born at VLBW have impaired strain despite preserved RV function assessed by standard techniques. Echocardiographic strain imaging may be an important tool to detect subclinical RV dysfunction in this clinically important and growing population.