Clinical and computed tomography characteristics of COVID-19 associated acute pulmonary embolism: A different phenotype of thrombotic disease?

van Dam, L.F.; Kroft, L.J.M.; van der Wal, L.I.; Cannegieter, S.C.; Eikenboom, J.; de Jonge, E.; Huisman, M.V.; Klok, F.A.

INTRODUCTION: COVID-19 infections are associated with a high prevalence of venous thromboembolism, particularly pulmonary embolism (PE). It is suggested that COVID-19 associated PE represents in situ immunothrombosis rather than venous thromboembolism, although the origin of thrombotic lesions in COVID-19 patients remains largely unknown. METHODS: In this study, we assessed the clinical and computed tomography (CT) characteristics of PE in 23 consecutive patients with COVID-19 pneumonia and compared these to those of 100 consecutive control patients diagnosed with acute PE before the COVID-19 outbreak. Specifically, RV/LV diameter ratio, pulmonary artery trunk diameter and total thrombus load (according to Qanadli) were measured and compared. RESULTS: We observed that all thrombotic lesions in COVID-19 patients were found to be in lung parenchyma affected by COVID-19. Also, the thrombus load was lower in COVID-19 patients (Qanadli score −8%, 95% confidence interval [95%CI] −16 to −0.36%) as was the prevalence of the most proximal PE in the main/lobar pulmonary artery (17% versus 47%; −30%, 95%CI −44% to −8.2). Moreover, the mean RV/LV ratio (mean difference −0.23, 95%CI −0.39 to −0.07) and the prevalence of RV/LV ratio >1.0 (prevalence difference −23%, 95%CI −41 to −0.86%) were lower in the COVID-19 patients. CONCLUSION: Our findings therefore suggest that the phenotype of COVID-19 associated PE indeed differs from PE in patients without COVID-19, fuelling the discussion on its pathophysiology.