THE
CLINICAL FEATURES OF ACUTE PULMONARY EMBOLISM IN AMBULATORY PATIENTS.
Susec O,
Boudrow D, Kline JA. Acad Emerg Med 1997 Sep;4(9):891-7.
OBJECTIVE:
To identify clinical findings and predisposing conditions associated with acute
pulmonary embolism (PE) in ambulatory patients being evaluated for PE.
METHODS:
A prospective observational study was conducted. A standardized multicomponent
data collection form was administered to ambulatory subjects being evaluated
for PE. The diagnosis of PE was confirmed or excluded using a combination of
scintillation lung scanning, lower-extremity venous Doppler ultrasonography,
and selective use of pulmonary angiography.
RESULTS:
Data collection was completed for 170 subjects, with 26 (15%) cases of PE.
Subjects with PE were significantly older (56 vs 41 years, 99% CI for
difference of 15 years [6 to 25 years]), were more likely to report unexplained
dyspnea (92% vs 69%, 99% CI for difference of 23% [7% to 40%]), and waited
longer after symptom onset to seek medical evaluation (73 vs 36 hours, 99% CI
for difference of 37 hours [11 to 63 hours]). No difference was found for multiple
variables commonly associated with PE. Assignment to risk categories was of
limited diagnostic utility. For example, low-risk assignment yielded 85%
sensitivity, 20% specificity; high-risk assignment: 31% sensitivity, 85%
specificity, with diagnostic accuracy below 80% in both categories.
CONCLUSIONS:
Among outpatients selected for evaluation for PE, further risk stratification
demonstrated poor diagnostic utility. Clinical features alone cannot be used to
differentiate presence or absence of PE in at-risk ambulatory patients.
COMMENTS:
Classically, most of us have been taught that patients with PE typically
present with an abrupt onset of symptoms, be it dyspnea or chest pain. This
study made an intriguing finding that the abrupt onset did not help to distinguish
between high or low risk patients. In fact, many patients seem to have an
increase delay from symptom onset to presentation in the ED.