[Diagnostic and therapeutic approach in patients with suspected pulmonary embolism: application of decision analysis]

Pulmonary arteriography is the most effective test for the diagnosis of pulmonary embolism but it is relatively complex and not without risk. Since around 70% of the patients with pulmonary embolism present thrombosis of the veins of the lower limbs, the performance of diagnostic phlebography and echography in patients suspected of having pulmonary embolism was analyzed and compared with pulmonary gammagraphy.

The methodology of decision analysis was applied to evaluate the performance of the different strategies in the cases of high, medium or low clinical suspicion of pulmonary embolism (prevalence of 70%, 30%, and 10%, respectively) in patients with or without concomitant diseases.

In patients with low suspicion, the use of echography allowed a survival of 97.8-98.2% of the ideal survival to be achieved. In those with medium suspicion, phlebography demonstrated the best performance (survival of 97.3-98.0% versus 96.3-97.3% achieved with echography). In cases og high suspicion isolated echography and phlebography showed low performance (survival lower than 96% of the ideal) with arteriography being required if the results of the aforementioned were negative. In any case, if the prevalence of pulmonary embolism is greater than 30%, it is better to treat all, rather than none, of the patients. The strategies based on pulmonary gammagraphy did not provide better results.

Echography and phlebography allow diagnosis of patients with low or medium suspicion of pulmonary embolism with an acceptable performance without carrying out arteriography. Nonetheless, high clinical suspicion requires the use of pulmonary arteriography in half of the patients.