Figure 3.

Possible mechanisms of pulmonary vascular disease after COVID-19. * Pulmonary vascular disease is defined as precapillary pulmonary hypertension (PH), in turn defined by right heart catheterization as mean pulmonary artery pressure > 20 mmHg, pulmonary capillary wedge pressure ≤ 15 mmHg and pulmonary vascular resistance > 2 Wood units. COPD: chronic obstructive pulmonary disease, FGF: fibroblast growth factor; group 3 PH: pulmonary disease associated with respiratory disease; group 4 PH: chronic thromboembolic pulmonary hypertension; PDGF: platelet-derived growth factor; PH: pulmonary hypertension; and VEGF: vascular endothelial growth factor.