Blood flow is restored most rapidly in the first day or two after a PE. Improvement slows thereafter and some deficits may be permanent. There is controversy over whether small subsegmental PEs need treatment at all and some evidence exists that patients with subsegmental PEs may do well without treatment.Once anticoagulation is stopped, the risk of a fatal pulmonary embolism is 0.5% per year.Mortality from untreated PEs was said to be 26%. This figure comes from a trial published in 1960 by Barrit and Jordan, which compared anticoagulation against placebo for the management of PE. Barritt and Jordan performed their study in the Bristol Royal Infirmary in 1957. This study is the only placebo-controlled trial ever to examine the place of anticoagulants in the treatment of PE, the results of which were so convincing that the trial has never been repeated as to do so would be considered unethical. That said, the reported mortality rate of 26% in the placebo group is probably an overstatement, given that the technology of the day may have detected only severe PEs. Predicting mortality
The PESI and sPESI (= simplified Pulmonary Embolism Severity Index) scoring tools can estimate mortality of patients. The Geneva prediction rules and Wells criteria are used to calculate a pre-test probability of patients to predict who has a pulmonary embolism. These scores are tools to be used with clinical judgment in deciding diagnostic testing and types of therapy. The PESI algorithm comprises 11 routinely available clinical variables.
The typical cut off is 500 μg/L, although this varies based on the assay. However, in those over the age of 50, changing the cut-off value to the persons age multiplied by 10 μg/L (accounting for assay which has been used) is recommended as it decreases the number of falsely positive tests without missing any additional cases of PE.When a PE is being suspected, several blood tests are done in order to exclude important secondary causes of PE. This includes a full blood count, clotting status (PT, aPTT, TT), and some screening tests (erythrocyte sedimentation rate, kidney function, liver enzymes, electrolytes). If one of these is abnormal, further investigations might be warranted to the issue.Troponin levels are increased in between 16 and 47% with pulmonary embolism. Imaging
In typical people who are not known to be at high risk of PE, imaging is helpful to confirm or exclude a diagnosis of PE after simpler first-line tests are used. Medical societies recommend tests such as the D-dimer to first provide supporting evidence for the need for imaging, and imaging would be done if other tests confirmed a moderate or high probability of finding evidence to support a diagnosis of PE.CT pulmonary angiography is the recommended first line diagnostic imaging test in most people.Ultrasound of the legs can confirm the presence of a PE but cannot rule it out. CT pulmonary angiography
CT pulmonary angiography (CTPA) is a pulmonary angiogram obtained using computed tomography (CT) with radiocontrast rather than right heart catheterization.