Resolution of acute pulmonary embolism using anticoagulation therapy alone in coronavirus disease 2019

OBJECTIVE: To investigate the radiographic resolution of acute pulmonary embolism (PE) using contrast-enhanced computed tomography (CECT) examinations in patients diagnosed with acute PE while hospitalized with coronavirus disease 2019 (COVID-19) and to understand the mid-term and long-term implications of anticoagulation therapy. METHODS: We identified patients with acute PE per CECT and at least one follow-up CECT from March 11, 2020, to May 27, 2021, using a prospective registry of all hospitalized patients with COVID-19 infection receiving care within a multicenter Health System. Initial and follow-up CECT examinations were reviewed independently by two radiologists to evaluate for PE resolution. The Modified Miller Score was used to assess for thrombus burden at diagnosis and on follow-up. RESULTS: Of the 6070 hospitalized patients with COVID-19 infection, 5.7% (348/6070) were diagnosed with acute PE and 13.5% (47/348) had a follow-up CECT examination. The mean ± standard deviation time to follow-up imaging was 44 ± 48 days (range, 3-161 days). Of 47 patients, 47 (72.3%) had radiographic resolution of PE, with a mean time to follow-up of 48 ± 43 days (range, 6-239 days). All patients received anticoagulation monotherapy for a mean of 149 ± 95 days and this included apixaban (63.8%), warfarin (12.8%), and rivaroxaban (8.5%), among others. The mean Modified Miller Score at PE diagnosis and follow-up was 4.8 ± 4.2 (range, 1-14) and 1.4 ± 3.3 (range, 0-16; P < .0001), respectively. Nine patients (19%) died at a mean of 13 ± 8 days after follow-up CECT (range, 1-27 days) and at a mean of 28 ± 16 days after admission (range, 11-68 days). Seen of the nine deaths (78%) deaths were associated with progression of COVID-19 pneumonia. CONCLUSIONS: Hospitalized patients with COVID-19 have a clinically apparent 5.7% rate of developing PE. In patients with follow-up imaging, 72.3% had radiographic thrombus resolution at a mean of 44 days while on anticoagulation. Prospective studies of the natural history of PEs with COVID-19 that include systematic follow-up imaging are warranted to help guide anticoagulation recommendations.