L11 Cardiovascular Disease 1

• Atherosclerosis


  Develops primarily in the large elastic & large-medium muscular arteries (aorta, carotid, iliac, coronary, popliteal)
• Atherosclerosis


  • Arteries supplying the brain, heart, kidneys & lower extremities are most often affected in symptomatic disease

  
• Major consequences of atherosclerosis

  • Myocardial infarction
  • Cerebral infarct
  • Aortic aneurysm
  • Sudden Cardiac death
  • Peripheral vascular disease
• Additional effects of atherosclerosis

  • Mesenteric occlusion
  • Chronic ischemic heart disease
  • Ischemic encephalopathy
  • Thrombus formation

  
• Atherosclerosis evolution: The response to injury hypothesis

  1. Normal

  2. Endothelial injury with adhesion of monocytes and platelets

  3. Migration of monocytes and SMC(smooth muscle cells) into the intima, with macrophage activation

  4. Macrophage and SMC uptake of modified lipids and further activation

  5. Intimal SMC proliferation and extracellular matrix (ECM elaboration), forming a well-developed plaque

  
• Cellular components of Atherosclerosis

  • Endothelial cells
  • Smooth muscle cells
  • Macrophages
  • Monocytes
  • Platelets

  
• Atheromatous fibro-fatty plaque


  Fibrous cap & necrotic centre

  
• Atheromatous plaque


  • Needle-shaped cholesterol crystals
  • Media thinning underneath the plaque due to repetitive compression by the unyielding plaque, during pulsation of the artery

  
• Complications of atherosclerosis


  • Aneurysms
  • Coronary artery disease
  • Myocardial infarction
  • Arrythmias
  • Heart failure
  • Stroke
• Aneurysms


  • Vessel wall stress
  • Poor intrinsic quality of vascular wall connective tissue
  • Imbalance of vascular wall collagen and synthesis caused by inflammation
  • Weakening and dilation of vessel wall
  • Loss of smooth muscle cells
  • Synthesis of non-elastic and non-collagen extra-cellular matrix

  
• Types of aneurysms


  • Saccular aneurysm
  • Fusiform aneurysm
• Systemic hypertension causes significant narrowing of arterioles of the vasa vasorum, leading to degenerative changes in the aorta
• Causes of Death (Europe 2008)

  • Over half of all deaths are due to cardiovascular diseases
• Virchow's triad


  Factors contributing to thrombus formation: abnormalities of blood flow, abnormalities of the vessel wall, and abnormalities of the blood

  
• Cardiovascular disease can lead to heart failure, which is the failure of the heart as a pump
• Pathology of the cardiovascular system

  • Failure of pump
  • Obstruction to flow
  • Regurgitation flow
  • Shunted flow
  • Cardiac conduction issue
  • Rupture of the heart or major vessel

  
• Congestive Heart Failure


  • Diminished systemic perfusion
  • Elevated backpressure in the pulmonary circulation
  • Right ventricular failure as a consequence of left ventricular failure
• Causes of Heart Failure

  • Atherosclerosis
  • Arrythmias
  • Myocardial infarction
  • Hypertension
  • Anaemia
  • Infection
  • Obesity
• Isolated right-sided heart failure can occur with lung issues, leading to a "nutmeg" appearance
• Ischaemic heart disease is a consequence of atherosclerosis
• There are different clinical forms of ischaemic heart disease
• Left-sided and right-sided heart failure have different consequences
• Lecture 12 will cover types of cerebrovascular disease, haemorrhagic stroke, ischaemic stroke, and valvular heart disease