Mean pulmonary arterial pressure >25mmHg at rest OR >30mmHg during exercise.
Increase in blood pressure in the pulmonary vessels.
May present spontaneously with no apparent underlying disease association, then known as primary pulmonary hypertension. More common in women
Pulmonary venous HTN: similar to LHF = orthopnoea, PND…
PAH: similar to RHF (because raised PAP causes secondary HTN in right heart) = dyspnoea, palpitations, chest pain/angina, haemoptysis, syncope, non-productive cough, fatigue
O/E: Altered heart sounds
- o Split S2
- o Loud P2
- o Parasternal heave
- o Present S3
- o Pulmonary regurgitation = RHF
- Elevated JVP
- Hepatojugular reflux
- Clubbing – all signs if RHF
Aetiology – cause, risk factors
Most common cause is COPD.
|PULMONARY VASCULAR DISORDERS
|DISTURBANCE OF RESPIRATORY CONTROL
|DISEASES OF THE LUNG AND PARENCHYMA
Can be subdivided into effects on lung circulation:
- 1. Precapillary
- 2. Capillary
Cause damage to the alveolar capillary mechanisms.
Pulmonary arterial hypoxaemia is a potent cause of vasoconstriction and hence of pulmonary hypertension = pulmonary vessel fibrosis/thickening = backpressure to RV = RHF = reduced flow to lungs = reduced LV EF = LHF due to lack of O2.
- 3. Postcapillary
Processes involve disease in structures distal to the pulmonary capillary bed.
Cause pulmonary hypertension through elevated venous pressures.
The Venice 2003 Revised Classification system:
- WHO Group I – Pulmonary arterial hypertension
- WHO Group II – Pulmonary venous hypertension associated with left heart disease
- WHO Group III – Hypoxic pulmonary hypertension associated with lung diseases and/or hypoxaemia
- WHO Group IV – Pulmonary hypertension due to chronic thrombotic and/or embolic disease
- WHO Group V – Miscellaneous
PAH = RHF (remember PA on R-side of heart)!!
PVH = LHF
Depend on cause and involve hypoxic vasoconstriction (COPD), decreased surface area of the pulmonary vascular bed (lung fibrosis) and increased right ventricular volume/pressure (congenital heart disease).
↑ pulmonary arterial pressure
Damage to the pulmonary endothelium
↑ Endothelium-derived vasoconstrictors
↑ peripheral vascular resistance
Pulmonary arterial hypertension/Hypoxic/thromboembolic pulmonary hypertension
- Vasoconstriction of PA, increased resistance and vessel fibrosis = PAH = RVH = RHF
Pulmonary venous hypertension
- Poor LV function = pulmonary stasis = pulmonary oedema/effusions
- Physical examination
- Pulmonary function tests
- Blood tests to exclude HIV, autoimmune diseases and liver disease
- ECG = RVH and RAH = eventually leads to LVH
- Arterial blood gas
- CXR = enlarged pulmonary arteries
- Diagnose via CTPA
- Treatment is directed at the primary cause
- Lifestyle changes, digoxin, diuretics, anti-coagulants, O2 therapy, CCBs
- Maximise LV function: diuretics, b-blockers, ACEi, MV/AV repair
- Other options: prostacyclins (prostaglandin I2), endothelin, bosartan, sildenafil
- 25% die in 6/12
- 40% survive 5y