PULMONARY HYPERTENSION

Pulmonary arterial hypertension (PAH) may be defined as a resting mean pulmonary artery pressure of >= 20 mmHg. (greater than 25 mmHg at rest or 30 mmHg after exercise; also diastolic pressure >8 mmHg)

Classifications:

five different types: arterial, venous, hypoxic, thromboembolic or miscellaneous

The Venice 2003 Revised Classification system

• WHO Group I - Pulmonary arterial hypertension (PAH)
  • Idiopathic (IPAH)
  • Familial (FPAH)
  • Associated with other diseases (APAH): collagen vascular disease (e.g. scleroderma), congenital shunts between the systemic and pulmonary circulation, portal hypertension, HIV infection, drugs, toxins, or other diseases or disorders
  • Associated with venous or capillary disease
• WHO Group II - Pulmonary hypertension associated with left heart disease
  • Atrial or ventricular disease
  • Valvular disease (e.g. mitral stenosis)
• WHO Group III - Pulmonary hypertension associated with lung diseases and/or hypoxemia
  • Chronic obstructive pulmonary disease (COPD), interstitial lung disease (ILD)
  • Sleep-disordered breathing, alveolar hypoventilation
  • Chronic exposure to high altitude
  • Developmental lung abnormalities
• WHO Group IV - Pulmonary hypertension due to chronic thrombotic and/or embolic disease
  • Pulmonary embolism in the proximal or distal pulmonary arteries
  • Embolization of other matter, such as tumor cells or parasites
• WHO Group V - Miscellaneous
• Plus Sickle cell disease and Kaposi's sarcoma (HHV 8)

Endothelin is thought to play a key role in the pathogenesis of PAH. It is more common in females and typically presents between the ages of 30-50 years. Pulmonary hypertension may of course develop secondary to chronic lung diseases such as COPD - PAH is diagnosed in the absence of this although certain factors increase the risk, including HIV, cocaine and anorexigens (e.g. fenfluramine). Around 10% of cases are inherited in an autosomal dominant fashion.

Features

• progressive exertional dyspnoea is the classical presentation

• other possible features include exertional syncope, exertional chest pain, ascites and/or peripheral oedema, hepatomegaly, cold extremities

• cyanosis

• clinical signs:

  • right ventricular heave: indicating right ventricular hypertrophy or dilatation
  • loud P2: early in the disease reflects increased pulmonary artery pressure and may be accompanied by a palpable P2 in severe cases. With advanced PAH there may be right ventricular failure leading to a soft S2
  • raised JVP with prominent 'a' waves: reflects increased resistance to right atrial emptying due to elevated right ventricular end-diastolic pressure. However, JVP is typically NOT elevated in many cases.
  • tricuspid regurgitation

  🩺 S1 + S2 (loud P2) + S3 + PSM loudest at the LLSE augmented by inspiration