Cross sectional Doppler echocardiography as the initial technique for the diagnosis of acute pulmonary embolism.

OBJECTIVE To determine the value of cross sectional Doppler echocardiography and derived indices of right ventricular pressure and function in the initial diagnosis of pulmonary embolism. BACKGROUND Most deaths from acute pulmonary embolism occur because of a delay in diagnosis. Ventilation-perfusion scans are not sufficiently sensitive, whereas angiography is invasive and associated with complications. The use of cross sectional Doppler echocardiography to assess acute changes in right ventricular filling pressure and function, and in pulmonary arterial systolic pressure and its relation to embolism has not been studied in a large population. METHODS 60 consecutive patients with acute symptoms or haemodynamic instability suggestive of pulmonary embolism were studied. Confirmatory investigations included a ventilation-perfusion scan (36 patients), angiography (18 patients), surgery (5 patients), or necropsy (5 patients). RESULTS There was evidence of right ventricular pressure or volume overload in all. This took the form of increased right ventricular end diastolic diameter and leftward bulging of the interventricular septum in diastole (56 patients); tricuspid valve regurgitation (56 patients) with the peak velocity of the regurgitant jet > 2.6 m/s; and a low collapse index for the inferior vena cava of < 40%, indicating raised mean right atrial pressure (in 49 patients). Intracardiac or pulmonary thrombi were visualised in 10 patients. In 14 patients treatment was undertaken on the basis of the echocardiographic signs alone. Four of them (with visible thrombi) recovered: the other 10 died. Lung emboli were demonstrated in 4 of 5 patients in whom necropsy was performed. CONCLUSIONS Cross sectional Doppler echocardiography is a sensitive technique for the rapid identification of right ventricular overload in acute pulmonary embolism. It enables further investigations on treatment to be appropriately directed without delay. Resolution of emboli can also be assessed by serial measurement of the described indices.