(a and b) Histological section showing prominence of the intracinar arterioles with medial hypertrophy corresponding to Grade I pulmonary hypertension (Heath-Edwards grading system), (H and E ×100 (a), ×200 (b). (c) Elastic von-Gieson's (EVG) stain highlighting the prominent intracinar arterioles (EVG ×100). (d and e) Muscle hypertrophy along with proliferation of intimal cells in the arterioles corresponding to Grade II pulmonary hypertension (Masson's trichrome ×100 (d), ×400 (e). Severe pulmonary artery hypertension following intracardiac repair of tetralogy of Fallot: An unusual finding. Kumar B, Puri GD, Manoj R, Gupta K, Shyam KS - Pulmonary circulation (2011 Jan-Mar). Not Altered. CC.
Pulmonary hypertension is systolic blood pressure in the pulmonary arterial circulation above 30mmhg where the mean pulmonary artery pressure is equal to or greater than 25 mm Hg at rest. There are five types:
- Group 1: Pulmonary arterial hypertension
- Group 2: Pulmonary hypertension due to left-sided heart failure
- Group 3: Pulmonary hypertension due to lung disease or hypoxia
- Group 4: Chronic thromboembolic pulmonary hypertension
- Group 5: Pulmonary hypertension with unknown causes
