The association between pulmonary vascular disease and respiratory improvement in infants with type I severe bronchopulmonary dysplasia

Objective To describe the association between echocardiographic measures of pulmonary vascular disease and time to respiratory improvement among infants with Type I severe bronchopulmonary dysplasia (sBPD). Study design We measured the pulmonary artery acceleration time indexed to the right ventricular ejection time (PAAT/RVET) and right ventricular free wall longitudinal strain (RVFWLS) at 34-41 weeks' postmenstrual age. Cox-proportional hazards models were used to estimate the relationship between the PAAT/RVET, RVFWLS, and the outcome: days from 36 weeks' postmenstrual age to room-air or discharge with oxygen (<= 0.5 L/min). Result For 102 infants, the mean PAAT/RVET and RVFWLS were 0.27 +/- 0.06 and -22.63 +/- 4.23%. An abnormal measurement was associated with an increased time to achieve the outcome (PAAT/RVET: 51v24, p < 0.0001; RVFWLS; 62v38, p = 0.0006). A normal PAAT/RVET was independently associated with a shorter time to outcome (aHR = 2.04, 1.11-3.76, p = 0.02). Conclusion The PAAT/RVET may aid in anticipating timing of discharge in patients with type I severe BPD.