Background: COVID-19 pneumonia is associated with extensive pulmonary microangiopathy and enlargement of the pulmonary artery (PA), while its progression after remission of the disease has not been investigated yet.

Aims and Objectives: The aim was to assess the diametral increase of the PA, as revealed on chest computed tomography (CT), in COVID-19 pneumonia, and further investigate its progression in the post-infectious state.

Methods: This was a retrospective cohort study of 55 patients with COVID-19 pneumonia, without history of pulmonary hypertension, who underwent CT pulmonary angiography (CTPA) in the acute phase of the infection, while in 20 of them a repeat CTPA was performed after 6-12 months. 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 test for paired data.

Results: A mean±SD MPAD of 3±0.3cm in the acute phase of COVID-19 pneumonia was significantly decreased to 2.8±0.3cm in the post-infectious state (p=0.0005). In a subgroup of 6 patients with an additional post-COVID-19 CT, a significant further decline in the diameter was observed (p=0.0313). Also, in accordance with the literature, a significant increase of MPAD in COVID-19 pneumonia was noted in a subgroup of 12 patients with a pre-COVID-19 CT (p=0.0371).

Conclusions: Enlargement of the PA is a common finding in COVID-19 pneumonia, accompanying the acute phase of the disease and regressing after its remission. The course of this reversible cardiovascular event in long COVID-19 is yet to be determined.

*NB & AMM equally contributed.