Pulmonary and cardiac variables associated with persistent dyspnea after pulmonary embolism.

Introduction Persistent dyspnea is common in follow-up after pulmonary embolism (PE), but the underlying mechanisms are poorly understood. Material and methods This cross-sectional study included subjects aged 18-75 years with confirmed PE by computed tomography pulmonary angiography (CTPA) 6-72 months earlier. A total of 180 participants underwent clinical examination, incremental shuttle walk test, laboratory tests, transthoracic echocardiography, pulmonary function tests and ventilation/perfusion scintigraphy. In further analysis, we divided participants into two groups; "dyspnea" or "no dyspnea", based on interview and questionnaires at inclusion. The association of cardiac and pulmonary variables with persistent dyspnea was assessed using multiple logistic regression analysis. Results In total, 44% (95% CI: 39%-51%) of the participants reported persistent dyspnea after PE. Age (adjusted odds ratio (aOR) 0.93 per year, 95% CI: 0.90-0.97, P = 0.001), body mass index (BMI) (aOR 1.14 per kg/m2, 95% CI: 1.04-1.25, P = 0.004), recurrent venous thromboembolism (VTE) (aOR 3.69, 95% CI: 1.45-9.38, P = 0.006) and diffusion capacity of the lung for carbon monoxide (DLCO) (aOR 0.95 per increase of 1%, 95% CI: 0.92-0.98, P = 0.001) were independently associated with persistent dyspnea. Conclusions Persistent dyspnea was prevalent after PE. Age, BMI and recurrent VTE were independently associated with dyspnea. Apart from reduced DLCO, no other cardiac or pulmonary variables were associated with persistent dyspnea.