The purpose of this study was to determine the prevalence and progression of pulmonary hypertension over a 5-year follow-up period in 28 patients with systemic lupus erythematosus (SLE) who were originally enrolled in an echocardiographic study of pulmonary hypertension in 1985 and 1986. Twenty healthy volunteers without cardiac or pulmonary disease participated as normal controls. Each patient and control underwent a complete Doppler echocardiographic study. Doppler echocardiographic recordings of tricuspid insufficiency, with saline contrast enhancement when necessary, were used to calculate pulmonary artery systolic pressure according to the modified Bernoulli equation. Doppler echocardiographic measurement of cardiac output was performed at rest for each subject, and pulmonary resistance was calculated by dividing the pulmonary artery systolic pressure by the cardiac output. These results were compared to results of the original studies to detect serial changes in pulmonary pressure and pulmonary resistance; results were also compared to the group of normal controls. The prevalence of pulmonary hypertension increased from 14% at the first study to 43% at follow-up. A significant increase in mean systolic pulmonary artery pressure was detected in the SLE patients during the follow-up period: 23.4 vs 27.5 mm Hg (p < 0.005). In addition, a significantly higher pulmonary artery pressure was detected in the SLE patients compared with the normal controls (p < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)