Echocardiographic assessment of pulmonary arterial pressure in the follow-up of patients with pulmonary embolism.

ABSTRACT

BACKGROUND: Echocardiography remains a clinically useful screening test for chronic thromboembolic pulmonary hypertension (CTEPH) in patients with a history of pulmonary embolism (PE). To devise an effective screening strategy, the definition of a high-risk group is necessary. METHODS: We examined a total of 744 patients with acute symptomatic pulmonary embolism (PE) who were enrolled in a Spanish multicenter study. Patients were monitored every 6months during the first two years, and then once a year thereafter. Transthoracic echocardiography was used to screen patients with a clinical suspicion of CTEPH during follow-up. Pulmonary arterial hypertension was defined as an estimated pulmonary artery systolic pressure (PAP)>50mm Hg. The index thromboembolic episode was considered severe if (a) the patient was immobilized for medical reasons; or (b) systolic blood pressure was less than 90mm Hg; or (c) troponin T values were above the reference range. RESULTS: The incidence of PAP>50mm Hg at 36months was 8.3% (95% confidence interval=4.6%-14.5%). Statistical analysis showed a highly significant association between a severe index thromboembolic episode and the subsequent detection of PAP>50mm Hg on echocardiography, with high positive likelihood ratio (2.40) and negative predictive value (>0.97). CONCLUSIONS: Patients with a severe index thromboembolic episode would constitute a high-risk group for the development of CTEPH. This group of patients should be subjected to a strict follow-up protocol.