Pulmonary HTN

• What is pulmonary arterial HTN (PAH)?


  Group of conditions characterised by progressive elevation of mean pulmonary arterial pressure to > 20 mmHg

  Not a diagnosis in itself
• What are the different causes/classification of PAH?


  Group 1

  • Idiopathic pulmonary HTN or connective tissue disease (e.g. SLE)

  Group 2

  • LHF (most common cause)
  • usually due to MI or systemic HTN

  Group 3

  • Chronic lung disease (e.g. COPD or pulmonary fibrosis)

  Group 4

  • Pulmonary vascular disease (e.g. PE)

  Group 5

  • Miscellaneous (e.g. sarcoidosis, glycogen storage disease & haematological disorders)
• Pathophys of PAH


  PAH occurs when there is profound vasculopathy (vasoconstriction, vascular remodelling & in situ thrombosis) → endothelial dysfunction → decreased vasodilator production → increased pro-contractile mediators, increased growth factor release, increase pro-inflammatory cytokine release → increased contractility of arteries, dysfunction of endothelium, over-proliferation of endothelial cells & vascular smooth muscle cells & increased thrombotic risk → increased pulmonary vascular resistance → increased pulmonary artery pressure
• What are the symptoms of PAH?


  SOB (progressive & exertional)

  Chest pain

  Fatigue

  Syncope

  Cough

  Haemoptysis

  Hoarseness
• What are the signs of PAH?


  Hypotension

  Tachycardia

  Cyanosis

  Loud pulmonary component of S2

  Third heart sound

  Pansystolic murmur (tricuspid regurgitation)

  Diastolic murmur (pulmonary regurgitation)
• What are the signs of LATE pulmonary HTN?


  Raised JVP

  Hepatomegaly

  Peripheral oedema

  Ascites

  Parasternal heave
• PAH causes strain of R side of heart → tries to pump blood through lungs → back pressure through R side of heart & into systemic venous system
• What are the RFs of PAH?


  Pre-existing diseases linked to pulmonary HTN

  Obesity

  Obstructive sleep apnoea

  Altitude (prolonged exposure)

  FHx

  Female
• What are the Inx of PAH?


  Obs

  Full Hx & examination

  ECG

  Wells score

  Bloods (FBC, U&Es, LFTs, CRP, NT-proBNP, ABG, serology (for HIV/Hep), autoimmune screen)

  CXR

  Echo (+ R heart catheterisation) -> to measure pressure in RA

  CT chest or V/Q scan

  Cardiac MRI

  Pulmonary function tests
• What will an ECG of PAH show?

  Signs of RHF

  • P pulmonale (peaked P waves)
  • R ventricular hypertrophy (tall R waves in V1 & V2, deep S waves in V5 & V6)
  • Right axis deviation
  • RBBB
• What is the CONSERVATIVE treatment of PAH?


  Exercise & pulmonary rehab

  Influenza & pneumococcal vaccination

  Contraceptive advice -> 30-50% increased mortality in pregnancy

  Psychosocial support
• What is the MEDICAL/SURGICAL treatment of PAH?


  Treat underlying cause

  Diuretics

  LTOT

  Digoxin (can increase CO)

  Anticoagulation

  Endothelin receptor antagonists (macitentan)

  Phosphodiesterase-5 inhibitors (sildenafil)

  IV prostaglandins (ilioprost)

  Ca+2 channel blockers (amlodipine)

  Cardiopulmonary transplantation