Residual pulmonary vascular obstruction and recurrence after acute pulmonary embolism. A single center cohort study

Up to 50% of patients with pulmonary embolism (PE) present lung perfusion defects after six months of anticoagulant treatment, suggesting residual pulmonary vascular obstruction (RPVO). The risk of recurrence in patients with RPVO remains unknown. The present study aims to assess the risk of recurrent venous thromboembolism (VTE) in patients with RPVO after a first symptomatic episode of PE.

Consecutive patients who survived a first objectively proven acute PE, treated for at least three months with anticoagulants, were included and followed prospectively. RPVO was defined as a pulmonary vascular obstruction of >10% on ventilation/perfusion lung scan performed at inclusion. Objectively proven VTE recurrences were registered and confirmed by an investigator unaware of the result of the ventilation/perfusion lung scan.

Among the 310 patients (median age: 61years) included in the study, 60 (19%) had RPVO. During a median follow-up of 51.3months, 66 patients (21.2%, 95% CI [17.5-26.7]) experienced recurrent VTE. In an adjusted cox proportional hazards analysis, we identified RPVO (HR 1.94; 95% CI [1.11-3.39]; p=0.026) and unprovoked PE (HR 3.56; 95% CI [1.79-7.07]; p=0.00051) as independent risk factors for recurrent VTE whereas extended anticoagulation therapy (HR 0.19; 95% CI [0.07-0.55]; p=0.00014) was associated with a low risk of recurrence.

The results suggest that RPVO is an independent risk factor of recurrent VTE after a first PE.