• Pulmonary Hypertension

    by  • 18/05/2013 • Respiratory

    Pulmonary hypertension

    Definition

    Mean pulmonary arterial pressure >25mmHg at rest OR >30mmHg during exercise.

    Increase in blood pressure in the pulmonary vessels.

    Presentation

    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

      1. o Split S2
      2. o Loud P2
      3. o Parasternal heave
      4. o Present S3
      5. o Pulmonary regurgitation = RHF
    1. Elevated JVP
    2. Ascites
    3. Hepatojugular reflux
    4. Clubbing – all signs if RHF

     

    Aetiology – cause, risk factors

    Most common cause is COPD.

    PULMONARY VASCULAR DISORDERS

    1. PE
    2. Primary pulmonary hypertension
    3. Pulmonary artery stenoses
    4. Schistosomiasis (parasite)

     

    DISTURBANCE OF RESPIRATORY CONTROL

    1. Sleep apnoea
    2. Obesity
    3. Cerebrovascular disease

     

    DISEASES OF THE LUNG AND PARENCHYMA

    1. COPD
    2. Other chronic lung diseases

     

    CARDIAC DISORDERS

    1. Mitral stenosis
    2. LVF
    3. Left atrial myxoma (cancer)
    4. Congenital heart disease with Eisenmenger’s reaction

     

    MUSCULOSKELETAL DISORDERS

    1. Kyphoscoliosis
    2. Poliomyelitis
    3. Myasthenia gravis

     

    MISCELLANEOUS

    1. Appetite suppression drugs: Dexfenfluramine
    2. Type 1 glycogen storage diseases
    3. Lipid storage diseases: Gauchers disease
    4. Connective tissue diseases: SLE, RA, scleroderma (15% of scleroderma pts have PAH)
    5. Hepatic cirrhosis
    6. Sickle cell disease
    7. Familial: BMPR-2 gene

     

     

    Can be subdivided into effects on lung circulation:

    1. 1. Precapillary
    2. 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.

    1. 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:

    1. WHO Group I – Pulmonary arterial hypertension
    2. WHO Group II – Pulmonary venous hypertension associated with left heart disease
    3. WHO Group III – Hypoxic pulmonary hypertension associated with lung diseases and/or hypoxaemia
    4. WHO Group IV – Pulmonary hypertension due to chronic thrombotic and/or embolic disease
    5. WHO Group V – Miscellaneous

     

    PAH = RHF (remember PA on R-side of heart)!!

    PVH = LHF

    Pathophysiology

    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

    1. Vasoconstriction of PA, increased resistance and vessel fibrosis = PAH = RVH = RHF

     

    Pulmonary venous hypertension

    1. Poor LV function = pulmonary stasis = pulmonary oedema/effusions

     

    Diagnosis/Investigation

    1. Physical examination
    2. Pulmonary function tests
    3. Blood tests to exclude HIV, autoimmune diseases and liver disease
    4. ECG = RVH and RAH = eventually leads to LVH
    5. Arterial blood gas
    6. CXR = enlarged pulmonary arteries
    7. Diagnose via CTPA

     

    Treatment/management

    1. Treatment is directed at the primary cause
    2. Lifestyle changes, digoxin, diuretics, anti-coagulants, O2 therapy, CCBs
    3. Maximise LV function: diuretics, b-blockers, ACEi, MV/AV repair
    4. Other options: prostacyclins (prostaglandin I2), endothelin, bosartan, sildenafil

     

    Prognosis:

    1. 25% die in 6/12
    2. 40% survive 5y 
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