Means of distinguishing pulmonary emboli and other causes of pulmonary hypertension.

SUMMARY AND CONCLUSIONS A selected group of patients with pulmonary hypertension has been presented to illustrate a diagnostic approach designed to determine the cause of the vascular disease. Wasted ventilation and other pulmonary function tests were not helpful in distinguishing pulmonary emboli from other causes of pulmonary hypertension. Our own experience and review of previous reports of pulmonary hypertension due to multiple emboli reveal that in virtually every case there was involvement of the elastic and large muscular arteries. Since occlusions of major and intermediate pulmonary arteries characterize recurrent emboli, lung scans and angiograms can be used to detect this group of patients with pulmonary hypertension. If these tests are normal and a specific cause for the pulmonary hypertension has not been discovered, a lung biopsy should be performed. ADDENDUM: Nadel and co-workers ( Am. J. Med. , 41:440, 1966) have recently emphasized the valuable role of pulmonary function studies in demonstrating the presence of pulmonary vascular occlusive disease before pulmonary hypertension develops.