Cardiovascular Disease Lecture 2

Cardiovascular Disease Lecture 2

• Learning Outcomes: Understanding various cardiovascular diseases, focusing on blood vessels, their pathophysiology, and potential therapies.

Vascular Disease

• Endothelium: Forms the innermost layer of blood vessels (single cell layer).
  • Mechanosensitive, responding to blood flow and pressure.
  • Actively regulates vascular tone (vasodilates and vasoconstricts).
  • Key regulator of vascular homeostasis.
  • Responsive to physical and chemical signals, producing factors to regulate processes like inflammation, thrombosis, and vascular permeability.
• Blood Flow & Shear Stress: Disturbed flow affects endothelial function, potentially leading to inflammation, apoptosis, and nitric oxide/prostacyclin bioavailability issues.
  • Low oscillatory shear at branch points can injure the endothelial layer.
• Vascular Reactivity Study: Measurements of artery contraction/relaxation in response to stimuli. Myography (common technique) measures vasoactivity in isolated blood vessels.
• Atherosclerosis: Lipoprotein-driven disease leading to plaque formation, narrowing of blood vessels, and potential thrombus formation/plaque rupture.
  • Leads to obstruction of blood flow to organs (heart, brain, extremities).
  • Plaque stages: Fatty streak, plaque, rupture, occlusion.
  • A stable plaque has a thick fibrous cap, while a vulnerable plaque has a thin fibrous cap.
  • Different factors like inflammation, oxidative stress, and loss of inhibitors drive vascular calcification.
• Vascular Calcification: Calcium deposits within arterial walls, common in older adults (60+).
  • Leads to vessel stiffness and increased blood pressure.
  • Medial and intimal calcification impacts arterial health.
  • Factors include age, diabetes, renal failure, and other diseases.
  • 2D ultrasound can identify calcification.
  • Pulse wave velocity measures arterial stiffness.
• Vulnerable vs. Stable Plaques: Distinguishing characteristics of vulnerable plaques include thin fibrous caps, large lipid pools, and inflammation. Stable plaques have opposing characteristics.
• Consequences of Atherosclerosis:
  • Acute Myocardial Infarction: A blocked coronary artery, decreasing oxygen to heart muscle, causing chest pain, shortness of breath, and potentially death.
  • Ischemic Stroke: Plaque fragments block blood vessels in the brain, hindering blood flow, leading to dizziness, visual problems, memory loss, or death.
  • Peripheral Vascular Disease (PVD): Large artery blockage in areas besides the heart, brain, or aortic arch.
    • Leading to claudication (muscle pain), colour changes, and slow-healing wounds.
    • Severe cases can result in limb loss and higher mortality rates.
  • Aortic Aneurysms: Weakening and bulging of the aorta, often asymptomatic, leading to rupture (a life-threatening condition). High-risk patients can undergo grafting (surgery).
• Peripheral Arterial Disease (PAD): Overlap with coronary and carotid manifestations.
  • High prevalence in high-risk individuals and those with coronary or cerebrovascular disease (CAD/CVD).
• Carotid Artery Problems:
  • Endarterectomy: A surgical procedure to remove plaque buildup in the carotid artery. In highly narrowed arteries, more than 70% blockage.
• Treatment of Coronary Artery Disease: Coronary Artery Bypass Graft (CABG) surgery can bypass blocked coronary arteries. Drug-eluting stents have been developed to inhibit proliferation at stent implantation sites.
• Exercise/Physical Activity: Protects the cardiovascular system and can impact endothelial function, reducing stiffness, and improving balance.

Explore the complexities of cardiovascular diseases in this lecture. Focus on the structure and function of blood vessels, the role of the endothelium, and the impact of blood flow on vascular health. Understand the pathophysiology and therapies associated with vascular diseases.