The assessment of pulmonary arterial pressures in bronchopulmonary dysplasia by cardiac catheterization and M‐mode echocardiography

Severe (Stage IV) bronchopulmonary dysplasia (BPD) has been associated with pulmonary hypertension and right heart failure, with a mortality rate of 39%. Recently, M-mode echocardiography has been used to measure right-sided systolic time intervals (the ratio of right ventricular pre-ejection period to ejection time; RVPEP/RVET), with a value greater than 0.35 predicting pulmonary hypertension. This measurement has also been used to predict outcome of BPD and response to oxygen therapy. A retrospective study of six infants with Stage IV BPD who had had cardiac catheterizations and M-mode echocardiography is reported. By catheterization criteria, four of the six had pulmonary hypertension. By echocardiographic criteria, only two of the six had unequivocally prolonged RVPEP/RVET ratios, and correlations with mean or diastolic pulmonary arterial pressures were poor (0.069 and 0.255, respectively). The validity of M-mode echocardiography in the assessment of the pulmonary vascular bed in Stage IV BPD is open to debate, and its role in predicting outcome and response to therapy is unknown.