Table 1.

Heath and Edwards’s scheme for hypertensive pulmonary vascular disease with progressive structural changes¹⁰

Grade	Pathology
0	Normal
1	Distal extension of muscle into distal arterioles and medial thickening of muscular arteries
2	Medial hypertrophy with cellular intimal proliferation in small muscular arteries
3	Progressive fibrous vascular occlusion, concentric intimal fibrosis
4	Progressive generalised arterial dilatation lesions, including plexiform lesions
5	Chronic dilatation with medial and intimal fibrosis, prominent plexiform lesions, angiomatoid lesions, pulmonary hemosiderosis
6	Necrotising arteritis