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:

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

  • At rest:
    • ≥ 25mmHg
  • On exertion:
    • ≥ 30mmHg

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

  • Fatigue
  • Weakness
  • Pre-syncope
  • Syncope
  • S.O.B.
  • Chest pain
  • Cough

Examination findings

  • Systolic murmur
    • Tricuspid regurgitation
  • Loud second heart sound
  • Ascites
  • Signs of right heart failure
  • Parasternal lift

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

  • Supplemental oxygen therapy
    • Especially when likely to reach altitudes ≥1500ft
  • Supervised exercise programs
    • Remain within symptom limits
  • Avoid pregnancy
    • Associated with a 30-50% mortality in PAH
  • Psychosocial support
  • Vaccination against;
    • Influenza
    • Pneumonia
  • Digoxin
    • May improve CO
  • Ca channel blockers
    • In vasoreactive patients
  • Prostanoids
    • In non-vasoreactive patients
  • Lung transplant surgery
    • In third stage treatment

Heart

 

 

 

 

 

 

 

 

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