# Reversibility of the Enlargement of the Pulmonary Artery in COVID-19 Pneumonia as a Marker of Remission of the Disease

## TL;DR

This study shows that enlargement of the pulmonary artery in COVID-19 pneumonia can reverse after recovery, suggesting it may be a marker of disease remission.

## Contribution

The study demonstrates that pulmonary artery enlargement in COVID-19 is reversible after disease remission, a novel finding for monitoring disease activity.

## Key findings

- Pulmonary artery diameter significantly decreased after recovery from COVID-19 pneumonia.
- The enlargement of the pulmonary artery is a reversible cardiovascular event linked to disease activity.
- Further decline in diameter was observed in patients with multiple post-COVID-19 CT scans.

## Abstract

Coronavirus disease 2019 (COVID-19) pneumonia is associated with extensive pulmonary microangiopathy and the enlargement of the pulmonary artery (PA), while its progression after the remission of the disease has not been investigated yet. The aim was to assess the diametral increase in the PA in COVID-19 pneumonia, as revealed on chest computed tomography (CT), and further investigate its progression. This was a retrospective cohort study of patients with COVID-19 pneumonia, without prior history of pulmonary hypertension, who underwent CT pulmonary angiography before, during, and after the infection. Pulmonary embolism was excluded in all cases. The main PA diameter (MPAD) was assessed in consecutive chest imaging. Statistical analysis was performed with the non-parametric Wilcoxon and Kruskal–Wallis tests, while correlations were performed with the non-parametric Spearman test. A mean ± SD MPAD of 3.1 ± 0.3 cm in COVID-19 pneumonia was significantly decreased to 2.8 ± 0.3 cm in the post-infectious state after 2–18 months in 31 patients (p-value: <0.0001). In a subgroup of six patients with more than one post-COVID-19 CT, a significant further decline in the diameter was observed (p-value: 0.0313). On the other hand, in accordance with the literature, a significant increase in the MPAD during COVID-19 pneumonia was noted in a group of 10 patients with a pre-COVID-19 CT (p-value: 0.0371). The enlargement of the PA is a common finding in COVID-19 pneumonia that regresses after the remission of the disease, indicating that this reversible cardiovascular event is a potential marker of disease activity, while its course in long COVID is yet to be determined.