Influence of extreme prematurity and bronchopulmonary dysplasia on cardiac function.

Abstract

Prematurity and bronchopulmonary dysplasia (BPD) are associated with poorly understood abnormalities of ventricular function. We therefore comprehensively compared biventricular function in infants with and without BPD. Prospective observational study in extremely preterm infants with (n=20) and without (n=38) BPD using conventional and advanced echocardiography at 28 days (T1) and near-term (T2). Infants with BPD had lower birth gestational age (26.7±1.9vs 27.4±1.1weeks, p=0.047) and weight (884±207vs 1108±190g, p=0.0001). BPD was associated with larger right ventricles (RV) and reduced RV systolic strain rate at T1 and pulmonary hypertensive indicators at T2 (pulmonary artery acceleration time BPD 51±17vs no BPD 63±12ms, p=0.017). At T1/T2, infants with BPD had lower RV tissue Doppler velocities (e', a' and s) and higher E/e' ratios (T1: BPD 10.4±2.4vs no BPD 6.2±3.1cm/sec, p=0.001; T2: BPD 8.0±3.1vs no BPD 5.6±2.6cm/sec, p=0.02), altered LV diastolic function (apical circumferential T1 early diastolic strain rate BPD 2.8±0.8vs no BPD 3.6±1.0/sec, p=0.04; T2 late diastolic strain rate, BPD 2.29 ± 0.99vs no BPD 1.67±0.84/sec, p=0.03) and LV rotational mechanics (T1: twist rate BPD 90±16vs no BPD 130±48deg/sec, p=0.008; untwist rate (UTR) BPD -69±90vs no BPD -147±68deg/sec, p=0.008; torsion BPD 2.78±0.56vs no BPD 4.48±1.74deg/cm, p=0.009; and T2: UTR BPD -132±69vs no BPD -179±57deg/sec, p=0.013). BPD is associated with altered RV diastolic function that persists near term, with elevated pulmonary vascular resistance, and with persistent alterations in LV apical strain rate and rotational mechanics.