Two projections (ipsilateral posterior oblique projection plus either a posteroanterior projection or ipsilateral anterior oblique projection) were obtained bilaterally unless the perfusion abnormality was localized to one side, in which case only one angiographic projection of the other side was performed (usually the ipsilateral posterior oblique projection). If a PE was found on one side, the study was usually terminated at that point, without examining the other lung.
The rate of PE was calculated from the number of positive pulmonary arteriograms divided by the total number of included patients, and 95% CIs were calculated. canadian neighbor pharmacy viagra
Results
Overall, 365 patients underwent pulmonary angiography for possible PE, and of these, 62 patients had both low-probability lung scans and negative lower extremity venous ultrasound examinations prior to angiography. In this latter group of 62 patients, 5 pulmonary arteriograms (8%; 95% CI, 2.7 to 18%) were positive for PE (Table 1) and 57 (92%) were negative for PE. Of the five patients with PE on angiography, four had small subsegmental emboli,
Discussion
Because of the relatively high frequency of PE in patients who had a high pretest clinical probability of PE despite having had a low-probability lung scan (40%; 95% CI, 16 to 68%), further testing to exclude or include the diagnosis of thromboembolic disease is necessary.