Physiological Changes Improving IC

• • what physiological changes are likely to occur in a walk training programme to influence pain characteristics (frequency and intensity) function and health related quality of life:
  • improved blood supply
  • but Leng 2000 - walking improvements were not related to improved blood flow (no change to ankle brachial index), which suggests theres no change in blood flow through the artery with the atheroma
  • classic raining effect on type 1 skeletal muscle fibres -> improved fibre aerobic efficiency
• Improving blood flow - angiogenesis:

  • Leng 2000 - walking improvements were not related to improved blood flow (no change to ankle brachial index), which suggests theres no change in blood flow through the artery with the atheroma
  • so how does blood supply improve:
  • promoting exercise into claudication -> collateral growth of arteries via release of mixture of ischaemic, inflammatory and growth factors including:
  • vascular endothelial growth factor (VEGF)
  • fibroblastic growth factor (FGF)
  • platelet derived growth factors (PDGF)
  • tumour necrosis factor (TNF)
  • promoting angiogenesis and the formation of a collateral circulation - occluded artery can receive blood from neighbouring arteries

  
• Improved aerobic efficiency:

  • skeletal muscle training effects on type 1 and 2a fibres:
  • increased capillarisation, myoglobin, mitochondria etc
  • improves muscles fibres capability of extracting and utilising oxygen aerobically to power activities
• • improved blood supply:
  • increased collateralisation -> increased supply capacity -> increased tissue
  • training effects on type 1 fibres:
  • physiological adaptation on type 1 skeletal muscle fibres -> increased efficiency of oxygen extraction/utilisation -> decreased tissue demand
  • both of the above:
  • decrease mismatch
  • increase ischaemic threshold
  • decrease symptoms
  • increase function
  • decrease disability
  • increase quality of life
  • delayed or avoided surgery
• • some patients:
  • use arterial vasodilators
  • are adherent to an exercise programme
  • embrace behaviour change
  • but for them, intermittent claudication does not improved and interferes with quality of life or worsens, leading to consideration of vascular surgery