Suspicion of pulmonary embolism in outpatients: nonspecific chest pain is the most frequent alternative diagnosis.

OBJECTIVES

Several recent studies have focused on identifying clinical predictors of embolism. However, although pulmonary embolism is ruled out in 70-85% of the patients in whom it is suspected, data on the clinical characteristics and discharge diagnosis of such patients are scarce. Our aim was to evaluate whether clinical characteristics would allow predicting alternative diagnoses other than pulmonary embolism thereby ruling out venous thromboembolism.

DESIGN

Retrospective analysis.

SETTING

Emergency centres of two teaching and general hospitals.

SUBJECTS: A total of 1090 consecutive outpatients admitted for clinically suspected pulmonary embolism and a diagnosis established by a validated algorithm and a 3-month follow-up.

OUTCOMES: Discharge diagnoses of patients in whom pulmonary embolism was ruled out were identified and regrouped into two categories: (i) nonspecific chest pain and (ii) diagnosis other than pulmonary embolism. Predictive accuracy of clinical and laboratory variables for diagnosing nonspecific chest pain was assessed by univariate and multivariate analysis.

RESULTS

In patients without pulmonary embolism, nonspecific chest pain (parietal chest pain, chest pain of unknown origin and pleuritis) was the most frequent discharge diagnosis (n = 334, 31% of the entire cohort, 43% of the patients without pulmonary embolism). Other patients without pulmonary embolism had a wide variety of diagnoses, of which the most frequent were bronchopneumonia (6.0% of the entire cohort) and heart failure (5.2%). In the multivariate analysis, seven variables were strongly associated with nonspecific chest pain: younger age (below 40 years), female gender, respiratory rate below 20 min(-1), heart rate below 100 min(-1), and absence of recent immobilization, dyspnoea and haemoptysis. Two of the 24 patients in whom all those characteristics were present had pulmonary embolism (8%, 95% CI 3-22%).

CONCLUSIONS

The most frequent discharge diagnosis in emergency ward patients in whom pulmonary embolism is ruled out is nonspecific chest pain. A clinical model did not allow to predict nonspecific chest pain with enough accuracy to rule out pulmonary embolism without further testing. Whether a more precise characterization of chest pain might allow an accurate identification of such patients deserves further study.