Echocardiography Assessment of Left Ventricular Function in Extremely Preterm Infants, Born at Less Than 28 Weeks' Gestation, With Bronchopulmonary Dysplasia and Systemic Hypertension

<bold>Background: </bold>The survival of smaller and more immature premature infants has been associated with lifelong cardiorespiratory comorbidities. Infants with bronchopulmonary dysplasia (BPD) undergo routine screening echocardiography to evaluate for development of chronic pulmonary hypertension, a late manifestation of pulmonary vascular disease. <bold>Methods: </bold>Our aim was to evaluate left ventricular (LV) performance in infants with BPD and pulmonary vascular disease who developed systemic hypertension. We hypothesized that infants with hypertension were more likely to have impaired LV performance. We present a single-center cross-sectional study of premature infants born at less than 28 0/7 weeks' gestational age with a clinical diagnosis of BPD. Infants were categorized by the systolic arterial pressure (SAP) at time of echocardiography as hypertensive (SAP >= 90 mm Hg) or normotensive (SAP <90 mm Hg). Sixty-four patients were included. <bold>Results: </bold>Infants with hypertension showed altered LV diastolic function with prolonged tissue Doppler imaging-derived isovolumic relaxation time (54.2 +/- 5.1 vs 42.9 +/- 8.2, P < .001), lower E:A, and higher E:e'. Indices of left heart volume/pressure loading (left atrium:aorta and LV end-diastolic volume [6.1 +/- 2 vs 4.2 +/- 1.2, P < .001]) were also higher in the hypertensive group. Finally, infants in the hypertensive group had higher pulmonary vascular resistance index (4.42 +/- 1.1 vs 3.69 +/- 0.8, P = .004). <bold>Conclusions: </bold>We conclude that extremely preterm infants with BPD who develop systemic hypertension are at risk of abnormal LV diastolic dysfunction. Increased pulmonary vascular resistance index in the hypertensive group may relate to pulmonary venous hypertension secondary to LV dysfunction. This is an important consideration in this cohort when selecting the physiologically most appropriate treatment.