Vascular Disease Flashcards
What is the intimal response to vascular injury?
- Smooth muscle cells are recruited to the site of vascular injury
- Smooth muscle cells divide
- Elaboration of extracellular matrix that leads to intimal thickening
What is arteriosclerosis?
“Hardening of the arteries” (arterial wall thickening and loss of elasticity)
What are 3 types of arteriosclerosis?
– Atherosclerosis
– Monckeberg’s medial calcific sclerosis
– Arteriosclerosis - hypertension induced
What are the main arteries affected by atherosclerosis?
• Elastic arteries
– Aorta
– Carotid
– Iliac
• Muscular arteries – Coronary – Popliteal – Renal – Mesenteric
What is a major risk factor for atherosclerosis?
Hyperlipidemia
What is the pathogenesis of atherosclerosis?
– Atherosclerosis is a chronic inflammatory response of the arterial wall to endothelial injury.
– Lesion progression involves interaction of lipoproteins, monocyte-derived macrophages, T lymphocytes and the cellular constituents.
What is the morphology of an atheroma?
Fibrous cap with a necrotic center.
What is the pathogenesis of an atheroma?
Deposition occurs between the internal elastic lamina and media and is found in the intimal layer of the membrane.
What are some complications of atherosclerosis?
MI
Stroke
Claudication
Aneurysm
What is Monckeberg’s Medial Calcific Sclerosis?
Nonobstructive Ca2+ deposition in the medial layer
What are most often affected arteries by Monckeberg’s Medial Calcific Sclerosis?
Medium arteries
What are the consequences of Monckeberg’s Medial Calcific Sclerosis?
Usually none as it is a non obstructive process
What are the types of Hypertension Induced Arteriosclerosis?
Hyaline
Hyperplastic
Hyaline Arteriosclerosis
Hypertension causes plasma protein leakage into the wall of the blood vessel that leads to pink hyaline thickening that causes lumen narrowing
Hyperplastic Arteriosclerosis
Caused by severe acute elevations in blood pressure that cause smooth muscle cells to respond with and onion skin like thickening that causes lumens narrowing and downstream ischemia
Aneurysm
Localized abnormal dilatation of a blood vessel
What are some possible causes of aneurysms?
- Poor intrinsic quality of vascular wall connective tissue
- Weakened vascular wall through loss of smooth muscle cells or inappropriate synthesis of extracellular matrix
- Altered balance of collagen degradation and synthesis
What is cystic medial degeneration?
Elastin fragmentation loss of smooth muscle cells leading to areas resembling “cystic” spaces
What are major causes of aneurysms?
– Atherosclerosis – HTN – Congenital defects – Inflammation • Infections • Vasculitis – Trauma
What are major factors that lead to AORTIC aneurysms?
Two most important disorders predisposing to aortic aneurysms are atherosclerosis and hypertension.
What is a false aneurysm?
Extravasation of blood that causes outputting into the outer layer that makes vessels look like they have an aneurysm but it is not
What is the pathogenesis of an Abdominal Aortic Aneurysm (AAA)?
The most common leading cause is atherosclerosis.
Atheromas compress the aortic media, compromise nutrient and waste diffusion from the vascular lumen into the arterial wall. The media undergoes degeneration and necrosis leading to overall arterial wall weakness and thinning.
What is a protein that is a major contributor to the development of AAA?
Matrix metalloproteinase (MMP) production by inflammatory cell infiltrates involved in the pathogenesis of atherosclerosis plays a key role.
What are the risks of AAAs?
- May impinge on adjacent structures (ie. ureter, vertebra)
- May have downstream embolism of atheroma or mural thrombus
What size AAAs increase the risk of rupture drastically?
5-6 cm
What is an aortic dissection?
- Aortic dissection refers to an Intimal tear of the aorta
- Blood then enters media of aorta
- A blood filled channel (“false lumen”) is created within the aortic media (usually between middle and outer thirds)
What are Type A aortic dissections?
Proximal lesions involving ascending aorta only or
ascending and descending aorta
What are Type B aortic dissections?
Distal - do not involve ascending aorta (usually begin distal to the subclavian artery)
What are the major contributing factors to aortic dissections?
Hypertension
Connective tissue abnormality
What is vasculitis?
It is inflammation of the wall of blood vessels and is immune mediated
