Pulmonary embolism at the emergency department during the COVID-19 pandemic. A comparative cohort study from a tertiary level hospital in southern Spain

Several studies have been published showing a significant increase in thrombotic complications in coronavirus disease 2019 (COVID-19) patients, including acute pulmonary embolism (PE). However, there is significant variability regarding published data on the number of computed tomography pulmonary angiography (CTPA) orders to rule out PE, frequency and characteristics of PE, and other factors that could have magnified the actual incidence of PE. The aim of this work is to analyze these factors during the first year of the pandemic. A longitudinal retrospective observational study was designed comparing two cohorts (preCOVID and COVID) of patients for whom an emergency CTPA was requested to rule out PE at the emergency department of our institution. Information was collected regarding the number of CTPAs requested, patient demographics, presence and extension of PE, and radiological signs of right ventricle strain/pulmonary hypertension (RVS/PH). Univariate and bivariate analyses were performed, with stratification by time intervals according to different pandemic waves in the COVID cohort. A total of 1905 patients (530 in the pre-COVID cohort and 1375 in the COVID cohort), with a mean age of 68.3 years (standard deviation, 16.5) and 981 (51.5%) women were included. No significant differences were observed regarding the incidence of PE between both cohorts. In patients with PE, no significant differences regarding age or sex were found, but a significantly higher frequency of peripheral PE was observed in the COVID cohort (42.0% vs. 6.5%, p < 0.001). Regarding signs of RVS/PH, a lower degree of septal deviation and contrast reflux to the inferior vena cava was observed in the COVID cohort, but no significant differences were observed in the right-to-left ventricular ratio. For the COVID cohort, the distribution of central vs. peripheral PE was similar in patients without laboratory-confirmed COVID-19 infection. Finally, the analysis of signs of RVS/PH stratifying by pandemic waves showed a lower frequency of RVS/PH signs in the 2nd and 3rd pandemic waves. In conclusion, despite a significantly higher number of CTPAs were performed during the pandemic, the incidence of PE was similar to that of the pre-pandemic period. A higher number of peripheral PE and less radiological signs of RVS/PH were observed during the pandemic. These findings could be explained by an increased incidental detection of PE during the pandemic. Our study has some limitations, mainly derived from its retrospective and single-center nature, which should be overcome in future research.