Clinical manifestation of pulmonary embolism.
Results of prospective studies have shown that physicians' estimate of clinical likelihoods of PE have predictive value. The ability of clinicians to assess the factors that determine the probability of disease based on clinical manifestations such as history and signs and symptoms at presentation, and to make bedside estimates of that probability, has not been systematically studied. Data suggest that that this would be a fruitful area of future investigation. Susec et al noted that there has been a total of three studies (including their own) which have examined the clinical features such as risk factors, signs, and symptoms associated with PE in ambulatory outpatients. Hence, the data collected thus far might not be generalizable to the ED patient population. As with other illnesses, the ED patients usually present later and more atypically. The prevalence of PE could be lower among this population compared with hospitalized patients, causing a lower positive predictive value, derivable from the clinical features and risk factors at presentation. Finally, the ED patient population is usually healthier and younger than the hospitalized patients, and it is well recognized that PE can be clinically silent in young patients and that 28% have no associated risk factors. Based on their finding, the authors argue that clinical pathways to risk stratify patients in an ambulatory setting could be less useful than anticipated. The validity of these findings needs further investigation, however.