Pulmonary Hypertension

An increase in mean pulmonary arterial pressure (PAP) ≥ 25mmHg at rest, as assessed by right heart catheterisation
- An increased blood pressure in the pulmonary arteries
Denotes an increase in the pressure the heart must exert in order to pump blood through the pulmonary circulatory system to the lungs

Below are the normal pulmonary and systemic pressures throughout the body:

Pulmonary pressures are, normally, much lower that those of the systemic system. An abnormally high pressure in the pulmonary system would be

There are 5 types of PH:

Pulmonary Arterial Hypertension (PAH)
- Causes:
- Idiopathic/heritable/drugs/toxins/CHD/HIV
- Fibrotic, pathological lesions affect distal pulmonary arteries (<500μm of diameter). Pulmonary veins are usually unaffected
PH due to left heart disease
- Causes:
- HF/valve pathology/left CHD
- Enlarged, thickened pulmonary veins. Lymph node enlargement.
PH due to lung disease
- Causes:
- COPD/ILD/sleep disorders/chronic exposure to high altitudes
- Medial hypertrophy. Obstructive proliferation of the distal pulmonary arteries. In COPD, destruction of the vascular bed may be a factor
Chronic ThromboEmbolic Pulmonary Hypertension (CTEPH)
- Intima of pulmonary artery medial layer replaced with lesions. Can cause differing grades of stenosis.
PH due to unclear or multifactorial mechanisms
- Haemolytic anaemias/splenectomy/sarcoidosis/chronic renal failure/thyroid disease

Symptoms

Examination findings

Tests and Dx

ECG
- RVH
- RAE
- Right axis deviation
Chest X-Ray
- ?RV or PA enlargement
- Loss of peripheral blood vessels
HRCT
CMR
Abdominal ultrasound
Pulmonary Angiography
Echocardiography
- TR jet peak velocity allows for calculation of PA pressure
- (PA Systolic pressure = TR pressure gradient + estimated RA pressure)
- Increased velocity of PV regurgitation
- Increased right heart dimensions
PFT
- Decreased lung diffusion capacity (40-80%)
- Mild – moderate decrease in lung volumes
- Peripheral airway obstruction
V/Q Scanning
- Look for treatable CTEPH
Immunology/bloods
- Serum tests to detect CTD and HIV
- Low titre anti-nuclear bodies may be elevated
- Positive thyroid disease be suggestive
Right heart catheterisation
- Swan-Ganz catheter insertion
- Most definitive diagnostic tool
- Pulmonary Capillary Wedge Pressure
  - ≤15mmHg

Treatment