Estimation of pulmonary arterial pressure by measuring the size of the right pulmonary artery in the suprasternal echocardiogram.

We studied 175 patients within 24 hr before cardiac catheterization with suprasternal echocardiography to evaluate whether pulmonary arterial hypertension can be derived by measuring the size of the right pulmonary artery. Group I consisted of 103 patients without pulmonary arterial hypertension (enddiastolic less than or equal to 12 mm Hg; mean pressure less than 20 mm Hg) and group II consisted of 72 patients with pulmonary arterial hypertension. The right pulmonary artery could be imaged in 91.2% of the patients studied. The size of the right pulmonary artery at the end of diastole in group I measured 17.9 +/- 0.2 mm (mean +/- SEM) and correlated best to the body surface area in this group (r = 0.63; p less than 0.001). The respective index size amounted to 9.9 +/- 0.1 mm/m2, and was different from that in group II with 14.1 +/- 0.4 mm/m2 (p less than 0.001). The systolic percent expansion of the right pulmonary artery in group I was 21.2 +/- 0.8% and in group II 9.2 +/- 0.8% (p less than 0.001). The index size of the right pulmonary artery for both groups correlated best to the pulmonary enddiastolic pressure (r = 0.82; p less than 0.001). The systolic per cent expansion showed a negative log linear relationship to the pulmonary enddiastolic pressure (r = 0.67; p less than 0.001). Thus, pulmonary arterial pressure can be derived by measuring the size of right pulmonary artery with suprasternal echocardiography.