Background: The exact prevalence and etiology of exertional dyspnea in the clinical course of acute pulmonary embolism (PE) have not yet been established.
Methods: A large cohort of consecutive patients diagnosed with acute PE was subjected to a dyspnea questionnaire and invited for cardiopulmonary work-up including the 6-min walk test, spirometry and echocardiography. The prevalence, severity, determinants and underlying diseases of exertional dyspnea were evaluated.
Results: Of the registered 877 patients, 259 (30%) had died and 11 (1.3%) were excluded for geographical reasons. From the remaining 607 patients, 217 reported exertional dyspnea (36%; 95% CI 32-40%) 3.6 ± 1.7 years after the PE. In 76% this dyspnea had developed or worsened after the acute PE. 421 patients completed the cardiopulmonary work-up. Cardiopulmonary comorbidity (OR 12; 95% CI 6.5-20), advanced age (OR 1.02 per year; 95% CI 1.01-1.03), higher BMI (OR 1.06 per kg/m(2); 95% CI 1.01-1.1) and a smoking history (OR 1.6; 95% CI 1.02-2.6) were identified as independent predictors of exertional dyspnea. A pre-defined dyspnea explaining diagnosis could be established in all patients with exertional dyspnea. In only 4 patients, this diagnosis was directly correlated to the acute PE. Increased severity of dyspnea was associated with decreased exercise performance (p < 0.001) and a higher number of dyspnea-related diagnoses (p < 0.001).
Conclusion: Exertional dyspnea is a frequent symptom in the long term clinical course of acute PE. More severe dyspnea results in decreased exercise capacity and increased burden of cardiopulmonary comorbidity. This dyspnea is likely to be unrelated to the past thromboembolic event in the vast majority of patients.
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