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.