Atrial natriuretic peptide in pulmonary emboli

The potent stimulation of ANP release by alveolar hypoxia raises the possibility that it might be an indicator of pulmonary emboli, a condition which is frequently not diagnosed. ANP was examined in hospitalized patients with pulmonary emboli evidenced by perfusion and ventilation scans, and in two control groups of patients with deep vein thrombosis or anginal syndrome. ANP was measured on days 1, 3, and 5 of hospitalization, while the patients were given heparin, and determined by double antibody radioimmunoassay. The level of ANP was 5 times higher in the pulmonary emboli group than in either of the control groups on day 1, and 3.5-4 times higher than the control groups on day 5. The ANP level remained low in the two control groups throughout the study. We suggest that ANP may serve as an indicator of the presence of pulmonary emboli, facilitating diagnosis of the condition.