Prospective Evaluation of Right Ventricular Function and Functional Status 6 Months After Acute Submassive Pulmonary Embolism

Background: No published data have systematically documented pulmonary artery pressure over an intermediate time period after submassive pulmonary embolism (PE). The aim of this work was to document the rate of pulmonary hypertension, as assessed noninvasively by estimated right ventricular systolic pressure (RVSP) of ≥ 40 mm Hg 6 months after the diagnosis of submassive PE. Methods: We enrolled 200 normotensive patients with CT angiography-proven PE and a baseline echocardiogram to estimate RVSP. All patients received therapy with unfractionated heparin initially, but 21 patients later received alteplase in response to circulatory shock or respiratory failure. Patients returned at 6 months for repeat RVSP measurement, and assessments of the New York Heart Association (NYHA) score and 6-min walk distance (6MWD). Results: Six months after receiving a diagnosis, 162 of 180 survivors (90%) returned for follow-up, including 144 patients who had been treated with heparin (heparin-only group) and 18 patients who had been treated with heparin plus alteplase (heparin-plus-alteplase group). Among the heparin-only patients, the RVSP at diagnosis was ≥ 40 mm Hg in 50 of 144 patients (35%; 95% CI, 27% to 43%), compared with 10 of 144 patients at follow-up (7%; 95% CI, 3% to 12%). However, the RVSP at follow-up was higher than the baseline RVSP in 39 of 144 patients (27%; 95% CI, 9% to 35%), and 18 of these 39 patients had a NYHA score of ≥ 3 or exercise intolerance (6MWD, < 330 m). Among heparin-plus-alteplase patients, the RVSP was ≥ 40 mm Hg in 11 of 18 patients at diagnosis (61%; 95% CI, 36% to 83%), compared with 2 of 18 patients at follow-up (11%; 95% CI, 1% to 35%). The RVSP at follow-up was not higher than at the time of diagnosis in any of the heparin-plus-alteplase patients (95% CI, 0% to 18%). Conclusions: Six months after experiencing submassive PE, a significant proportion of patients had echocardiographic and functional evidence of pulmonary hypertension.