Incidental pulmonary embolism in cancer and noncancer patients: Prospective cohort study

Background: Clinical picture and outcome of incidental pulmonary embolism (iPE) compared to symptomatic pulmonary embolism (sPE) remain unclear. Methods: Demographics, recurrent venous thromboembolism (VTE), mortality, major bleeding, and clinically relevant nonmajor bleeding (CRNMB) were compared between iPE and sPE patients who were followed prospectively at Mayo Thrombophilia Clinic (March 1, 2013 to August 1, 2020). Results: Out of 3576 VTE patients, 1417 (39.6%) had PE: 562 (39.7%) iPE and 855 sPE. Patients with cancer were more likely to have iPE (400 iPE vs. 314 sPE) compared to those without cancer (162 iPE vs. 541 sPE). VTE recurrence rate (all per 100 person-years) was similar in all iPE and sPE patients (3.34 vs. 3.68, p =.50), with cancer (4.16 vs. 4.89, p =.370), and without cancer patients (0.89 vs. 2.80, p =.25). Higher mortality observed in all patients with iPE compared to sPE (46.45 vs. 23.47, p <.001) and with cancer (56.41 vs. 45.77, p =.03) became not significant after adjustment for age, antiplatelet therapy, metastases, and cancer location. Noncancer iPE patients had higher mortality (15.95 vs. 7.18, p =.006) even after adjustment (p =.05). The major bleeding rate was also higher in all patients iPE compared to sPE (7.10 vs. 3.68, p =.03), but not after adjustment (p =.974); higher major bleeding rate in noncancer patients (6.49 vs. 1.25, p =.007) remained significant after adjustment (.02). CRNMB rate was similar to iPE and sPE patients. Conclusion: iPE represents a more serious clinical condition compared to sPE as indicated by the higher mortality and major bleeding but these differences reflect underlying comorbidities rather than the seriousness of the embolic event.