Whether the localization of nonmassive pulmonary embolism (PE) is associated with the short-term and long-term prognosis of patients remains unknown. Our aim was to characterize associations of nonmassive PE localization with risks of recurrent VTE, major bleeding, and mortality during and after anticoagulation.
Among participants of the Registro Informatizado de la Enfermedad ThromboEmbòlica (RIETE) registry with incident symptomatic nonmassive PE diagnosed by CT scan, we compared risks of recurrent VTE, major bleeding, and mortality during and after anticoagulation between central PE (main pulmonary artery) and noncentral PE (more peripheral arteries) using Cox proportional hazard-adjusted models.
Of the 6,674 participants, patients with central PE (40.5%) had age (mean 66 years), sex (46.9% male sex), and proportion of idiopathic (45.0%) and cancer-related (22.3%) PE that were similar to those of patients with noncentral PE. During anticoagulation (5,256.1 patient-years), the risk of recurrent VTE was similar between the two groups (2.5 vs 2.1 per 100 patient-years; adjusted hazard ratio [aHR], 1.32; 95% CI, 0.91-1.90), as were risks of major bleeding and mortality. After anticoagulation was discontinued (2,175.4 patient-years), participants with central PE had a borderline greater risk of recurrent VTE than did participants with noncentral PE (11.0 vs 8.0 per 100 patient-years; aHR, 1.34; 95% CI, 1.01-1.78) but not when restricted to participants after unprovoked PE (13.8 vs 11.9 per 100 patient-years; aHR, 1.15; 95% CI, 0.79-1.68; P = .48). Risks of major bleeding and mortality were similar.
In nonmassive PE, central localization of PE is associated with greater risk of recurrent VTE after anticoagulation cessation. However, the low magnitude of this association and the absence of association after unprovoked PE suggest that the clinical relevance of this finding is limited and that the duration of anticoagulation should not be tailored to PE localization after nonmassive unprovoked PE.