Cardiac Pathology - Vascular Disease Flashcards
(45 cards)
What are the 5 main mechanisms of vascular disease?
- Gradual lumen obstruction (atherosclerosis (arteries/aorta) or arteriolosclerosis (arterioles))
- Sudden lumen obstruction (thrombosis, emoblism, or aortic/arterial dissection)
- Aneurysm/dissection (prefers larger caliber arteries (esp. aorta) with principle risk of rupture
- Vasculitis (spectrum of inflammatory diseases affecting aorta down to arterioles/capillaries/venules)
- Extrinsic vascular compression
What are examples of extrinsic vascular compression?
- Compartment syndromes: vascular collapse from surrounding hemorrhage/edema/inflammation. in a limited anatomic compartment (extremities, abdomen)
- -Vena cava syndromes (SUPERIOR & inferior): obstruction to caval flow usually caused by surrounding neoplastic adenopathy or occasionally from intra-caval tumor thrombus
What is MECHANISM #1 for vasculitis?
- VAST MAJORITY of most clinically morbid disease is ARTERIAL and dominated by ATHEROSCLEROSIS
- atherosclerosis prefers larger vessels (aorta, medium to large arteries): causing gradual lumen obstruction +/- aneurysmal dilation.
What are the main risk factors for atherosclerosis?
-Older age, male gender, post-menopausal women, FAMILIAL tendency (typically polygenic/multifactorial), hypercholesterolemia, hypertension, diabetes mellitus, and smoking
What is the pathogenesis associated with atherosclerosis?
- Only crudely understood
- “endothelial injury” leading to:
- -intimal collection of lipid-laden macrophages
- -Smooth muscle migration from media into intima
- -Intimal accumulation of extra-cellular matrix
- -WBCs as co-factors in above
What is an unstable plaque?
Inc. risk of surface rupture and platelet aggregation/fibrin clot formation = thrombosis - with risk of complete/sudden lumen occlusion
What is HTN or diabetes mellitus is present with atherosclerosis?
- Large vessel atherosclerosis is accelerated
- Arterioles become gradually obstructed (arteriolosclerosis)
What does arteriolosclerosis cause in HTN and diabetes?
Typically non-bypassable disease in the microcirculation: kidneys, retina, CNS/peripheral nervous system, heart and skin (e.g. diabetic foot ulceration)
-Untreatable small vessel vasculitis
What are the two types of hypertension?
95% - “essential” with multifactorial/polygenic/familial factors
5% - “secondary” (usually from reveal artery or adrenal disease) = potentially curable cases (DONT MISS)
What is malignant/accelerated HTN?
Medical emergency!!
Inc. risk of acute end-organ injury: heart, CNS, kidneys
What causes chronic end organ effects in HTN?
-Arteriolosclerosis, accelerated atherosclerosis and Inc. left ventricular and aortic strain: CAD/ischemic heart disease, thoracic aortic aneurysm, LVH/CHF, stroke (ischemic or hemorrhagic), retinopathy, nephropathy
What is the #2 mechanism of atherosclerosis?
-Sudden lumen occlusion
–> most common cause of life-threatening vascular events
Arterial: acute myocardial infarction, stroke, mesenteric ischemia/bowel infarction and acute leg ischemia/gangrene
What is an embolism?
Cardiac source until proven otherwise (e.g. left atrial or left ventricular thrombus)
Sudden lumen occlusion: Arterial:
- Acute myocardial infarction, stroke, mesenteric ischemia/bowel infarction and acute leg ischemia/gangrene
- Vast majority: unstable atheromatous plaque with rupture causing overlying occlusive thrombosis
- Embolism
- Aortic dissection can suddenly occlude orifices of exiting arteries
What happens in Veins with occlusive thrombosis?
- DVT: (usually iliofemoral veins) with risk of PE and sudden death: serum D-dimer testing and CT angiography
- Splanchnic venous thrombosis (mesenteric, portal/splenic, hepatic veins) = risk of bowel infarction or Budd-Chiari syndrome: Inc. likelihood of associated congenital hyper coagulable state or chronic myeloproliferative syndrome
What do you see and what is first treatment in PE?
Shortness of breath, chest pain
-Tx: first heparin, then may need vena cava filter/”strainer” if more traveling thrombi
With any DVT, what is it usually caused by?
Surgery/trauma/sepsis OR due to serious underlying congenital or acquired hyper coagulable state (e.g. malignancy)?
What is the #3 mechanism of atherosclerosis?
Aorta/large artery aneurysm or dissection due to arterial wall weakening
What is aneurysmal dilation?
- Especially affects aorta (Laplace’s law) but also can involve medium to large arteries
- Mechanism of weakening:
- -Ordinary atherosclerosis (esp. infra-renal abdominal aorta in smokers)
- Hypertension (esp. ascending throacic aorta)
- Misc. causes: inherited connective tissue disease (e.g. Marfan’s), vasculitis (Takayasu’s and giant cell - big vessel vasculitis), connective tissue/autoimmune diseases, and infection or aortic/arterial wall
- –> most feared complication: rupture and exsanguination
What is Aortic Dissection?
Dissecting hemorrhage/hematoma within aortic wall
- Type A (most lethal) = ascending +/- more distal aorta –> may lead to tamponade & coronary artery occlusion
- Type B = descending aorta and/or aortic arch
What are the pre-disposing factors for dissection?
- HTN if patient > 40 yrs
- Inherited connective tissue disorder (e.g. Marfan’s) if patient
What is the #4 mechanism of atherosclerosis, Vasculitis?
=inflammation of vascular wall ranging from neutrophilic to granulomatous
- lumen compromise secondary to inflammatory reaction +/- overlying thrombosis
- can be associated with secondary aneurysms
- Clinically a spectrum from benign skin limited disease (luekocytoclastic vasculitis) commonly to aggressive visceral vasculitis disease with high mortality (e.g. ANCA-associated vasculitides)
What age groups are vasculitic diseases/symptoms common?
- Largely adult diseases:
- -Except Henoch-Schonlein Purpura (HSP = IgA-related vasculitis) and Kawasaki disease (risk of coronary vasculitis)
- Vasculitis in middle-aged/elderly adults:
- if affecting distribution of external carotid artery = GIANT CELL (TEMPORAL) arteritis with risk of vision loss: diagnose with temporal artery biopsy and Rx with corticosteroids
What vasculitis might you see commonly in practice?
Giant cell arteritis: external carotid system is inflamed –> risk of vision loss
