Vascular Part I - Robbins Flashcards
What are berry aneurysms? Where are they typically found?
Outpouchings in cerebral vessels due to congenital wall weakness
2% of population
Rupture can cause fatal subarachnoid hemorrhage
Typically found in the Circle of Willis
What are berry aneurysms usually associated with?
Autosomal dominant polycystic disease 10-15%
What are arteriovenous fistulas? How do they arise?
abnormal connection between artery and vein (bypass capillaries)
Most commonly a developmental defect, but may arise secondary to inflammation, trauma, rupture
What can arteriovenous fistulas lead to?
Rupture and hemorrhage
Large enough, it can create significant left-to-right vascular shunting, with increased venous return that leads to high-output cardiac failure
What is fibromuscular dysplasia?
Focal thickening of intima and media of medium to large muscular arteries due to hyperplasia and fibrosis, resulting in stenosis
What stimui can induce change in endothelial cell function, leading to an activated state?
Turbulent blood flow HTN complement, bacterial products, lipid products, glycation end products (diabetes) Viruses Hypoxia, acidosis Tobacco smoke
What is the activated state of the endothelium
Increased expression of procoagulants, adhesion, proinflammatory factors, vasoactive factors, GFs
Factors that can cause SMC contraction and/or proliferation and matrix synthesis
Endothelial dysfunction often characterized by….
Procoagulation
Proinflammation
Smooth muscle stimulation
What is neointima?
Injured endothelium and underlying vessel wall “heal” by stimulating SMC ingrowth and ECM production, leading to intimal thickening
What is the stereotypical response to vascular injury?
With loss of endothelial cells or prolonged dysfunction, intimal thickening occurs
What is intimal thickening?
SMC from media migrate to intima, where they proliferate and elaborate ECM
Untreated hypertension can lead to what?
vessel and end-organ damage
What can untreated hypotension lead to?
inadequate organ perfusion
What is HTN a risk factor for?
Atherosclerosis Aortic dissection HTN heart disease Stroke HTN renal disease
How often is HTN essential?
90-95%
Most people with HTN have idiopathic or essential HTN
What is secondary HTN usually caused by?
Renal (acute glomerulonephritis, CRD, polycystic D, RAS, RAFD, vasculitis, renin-producing tumors) or endocrine disorder (adrenocortical hyperfunction, exogenous hormones, pheochromocytoma, hyper/hypo thyroidism, pregnancy)
What are the risk factors for essential HTN?
High sodium intake Obesity Stress Smoking Physical inactivity
BP = ?
CO x Peripheral resistance
What are the humoral constrictors of peripheral vasculature?
Angiotensin II Catecholamines Thromboxane Leukotrienes Endothelin
what are the humora dilators of vasculature?
PGs, kinins, NO
What is blood volume and vascular tone modified and maintained by?
Renin-angiotensin-aldosterone system
Mutations in what enzymes that influence aldosterone synthesis leads to increased aldosterone production?
11-beta hydroxylase, 17 alpha hydroxylase
What is Liddle syndrome?
Mutation in renal epithelial Na channel protein leading to increased sodium resorption
What accelerates the development of atherosclerosis and also causes arteriolar structural changes that potentiate aortic dissection and cerebrovascular hemorrhage?
HTN
What happens with Hyaline arteriolosclerosis?
Increae sm m matrix synthesis Plasma protein leakage across damaged endothelium Homogenous pink (hyaline) thickening of the vessel wall, with luminal narrowing Plasma proteins traversed activated endothelium is the source of hyaline
What is hyperplastic arteriolosclerosis?
Occurs in sever HTN
SMC form concentric lamellations (‘onion skinning’ - reduplicated BM and SMC proliferation) with resultant luminal narrowing
Associated with necrotizing arteriolitis
What are the three patterns of arteriosclerosis?
Arteriolosclerosis: downstream ischemia
Muckeberg medial sclerosis: medial calcification in muscular aa; older
Atherosclerosis
What does the fibrous cap of atherosclerotic plaque contain?
SMC, Mo, Foam cells, lymphocytes,collagen, elastin, proteoglycans, neovascularization