Pulmonary embolism severity before and during the COVID-19 pandemic

Abstract

Objectives: Early in the coronavirus 2019 (COVID-19) pandemic, a high frequency of pulmonary embolism was identified. This audit aims to assess the frequency and severity of pulmonary embolism in 2020 compared to 2019.

Methods: In this retrospective audit, we compared computed tomography pulmonary angiography (CTPA) frequency and pulmonary embolism severity in April and May 2020, compared to 2019. Pulmonary embolism severity was assessed with the Modified Miller score and the presence of right heart strain was assessed. Demographic information and 30-day mortality was identified from electronic health records.

Results: In April 2020, there was a 17% reduction in the number of CTPA performed and an increase in the proportion identifying pulmonary embolism (26%, n = 68/265 vs 15%, n = 47/320, p < 0.001), compared to April 2019. Patients with pulmonary embolism in 2020 had more comorbidities (p = 0.026), but similar age and sex compared to 2019. There was no difference in pulmonary embolism severity in 2020 compared to 2019, but there was an increased frequency of right heart strain in May 2020 (29 vs 12%, p = 0.029). Amongst 18 patients with COVID-19 and pulmonary embolism, there was a larger proportion of males and an increased 30 day mortality (28% vs 6%, p = 0.008).

Conclusion: During the COVID-19 pandemic, there was a reduction in the number of CTPA scans performed and an increase in the frequency of CTPA scans positive for pulmonary embolism. Patients with both COVID-19 and pulmonary embolism had an increased risk of 30-day mortality compared to those without COVID-19.

Advances in knowledge: During the COVID-19 pandemic, the number of CTPA performed decreased and the proportion of positive CTPA increased. Patients with both pulmonary embolism and COVID-19 had worse outcomes compared to those with pulmonary embolism alone.

Figure 1.

Example images from a patient with COVID-19 showing (A) pulmonary embolism on vascular windowed images and (B) peripheral ground glass opacification and consolidation on lung windowing in a typical pattern.

Figure 2.

Percentage of CTPA positive for pulmonary embolism by requesting location, comparing April and May 2019 to 2020. CTPA, computed tomography pulmonary angiography.

Figure 3.

Pulmonary embolism severity assessed with the Modified Miller Score in 2019 (grey) and 2020 (yellow). The smoothed density estimates are shown by the solid lines and the medians by the vertical dotted lines.

Figure 4.

Modified Miller score (A) and RV/LV ratio (B) in patients with and without mortality at 30 days, comparing patients with pulmonary embolism in 2019 and pulmonary embolism with and without COVID-19 in 2020 (Median and interquartile range). LV, left ventricle; RV, right ventricle.