Although hypercoagulability has been reported in critically ill patients with coronavirus disease 2019 (COVID-19), results from a small study revealed that patients with COVID-19 did not have a higher prevalence of pulmonary embolism (PE) compared to those without COVID-19. Findings from this study, published in PLoS One, did show that patients with COVID-19 and suspected PE had lung changes that resembled infarct pneumonia and organizing pneumonia (OP).
Researchers conducted retrospective analysis of data of 68 adult patients with COVID-19 confirmed by real-time polymerase chain reaction who were consecutively admitted to isolation wards and intensive care units at the University Hospital Zurich in Switzerland. Patients in this study were admitted to the hospital between March and April 2020.
In the 2019 and 2020 cohorts, 175 and 157 patients, respectively, underwent computed tomography (CT) pulmonary angiography (CT-PA) for PE at the institution were also included in this study as control individuals. For all 3 cohorts, independent readers assessed for the presence and location of PE. Additionally, parenchymal changes typical of COVID-19 pneumonia, infarct pneumonia, and OP were examined in the cohort of patients with COVID-19.
The median age of the COVID-19 cohort was 59 years. A total of 38 patients with COVID-19 who underwent chest-CT fulfilled criteria for suspected PE and underwent CT-PA. Approximately 13.2% of patients with COVID-19 presented with PE on CT-PA compared with 9.1% of patients in the 2020 control group and 8.9% in the 2019 control group (P =.452).
Up to half of the patients with COVID-19 who had patterns typical of infarct pneumonia on CT also demonstrated signs of right heart failure and pulmonary hypertension. Additionally, approximately 50% of patients with COVID-19 had changes on CT that resembled those in OP. No statistically significant difference was found between patients with COVID-19 with suspected PE and without suspected PE in terms of the presence of triangular or wedge-shaped peripheral ground-glass opacification (21.1% vs 13.3%; P =.465).
Study limitations included the retrospective nature and small sample size, as well as the lack of histopathologic confirmation of OP or infarct pneumonia in the overall population.
The investigators concluded that the findings may imply that vascular pathology in COVID-19 is microangiopathic “and hence generally too small to be captured directly by CT.” They suggested that “[v]isible lung changes in CT might be a surrogate for the underlying pathology caused by [severe acute respiratory syndrome virus 2] unveiling the invisible endothelial changes within the lungs. An increased [pulmonary artery and aorta] ratio may be a hint to the underling pathology and warrant[s] further investigation.”
Martini K, Blüthgen C, Walter JE, Nguyen-Kim TDL, Thienemann F, Frauenfelder T. Patterns of organizing pneumonia and microinfarcts as surrogate for endothelial disruption and microangiopathic thromboembolic events in patients with coronavirus disease 2019. Published online October 5, 2020. PLoS One. doi:10.1371/journal.pone.0240078