[Incidence of symptomatic and asymptomatic chronic thromboembolic pulmonary hypertension]

To assess the incidence of long-term symptomatic and asymptomatic chronic thromboembolic pulmonary hypertension (CTEPH) in a cohort of patients with acute symptomatic pulmonary embolism (PE), and the potential risk factors for its diagnosis.

We conducted a prospective, long-term, follow-up study in 110 consecutive patients with an acute episode of pulmonary embolism (PE). All patients underwent transthoracic echocardiography (TTE) two years after the diagnosis of PE was made. If systolic pulmonary artery pressure exceeded 40 mm Hg and there was evidence of residual PE either by ventilation-perfusion or CT scan, patients underwent right heart catheterisation to confirm the diagnosis. In asymptomatic patients, right heart catheterisation was performed if a repeated TTE still demonstrated persistent pulmonary hypertension six months after the first.

CTEPH was diagnosed in 10 (6 patients during follow-up, and 4 at the end of the study) of the 110 patients (9.1%; 95% confidence interval [CI], 3.7 to 14.5%). All patients showed symptoms related to the disease according to a structured questionnaire. In the multivariate regression analysis, only concomitant age (relative risk [RR] 1.2 per age; 95% CI, 1.0 to 1.3; P=0.03) and previous PE (RR 5.7; IC 95%, 1.5 a 22.0; P=0.01) were independent predictors of CTEPH.

CTEPH cumulative incidence appears to be higher than previously reported. All patients had symptoms related to the disease.