Acute pulmonary embolism.

In the absence of significant symptoms and signs the diagnosis of pulmonary embolism remains difficult. Sensitivity and specificity of laboratory tests, chest x-ray, ECG, echocardiography and venous studies on their own is low. Ventilation-perfusion scanning establishes or excludes the diagnosis only in those patients with "high-probability" or "normal" scanning results. The diagnosis of pulmonary embolism should be made by combining clinical assessment, several diagnostic techniques, and, finally, pulmonary angiography in doubtful cases. Heparin remains the standard therapy for patients with stable hemodynamics. Thrombolytic therapy is recommended in hemodynamically compromised patients. In short-term dose regimens the thrombolytic agents urokinase and rt-PA seem to be equally effective. So far, however, no study has proven that thrombolytic therapy significantly reduces mortality in pulmonary embolism.