Vascular Surgery Flashcards
Thromboangitis obliterans
Chronic recurring, inflammatory, vascular occlusive disease of peripheral arteries and veins of the extremities
Less common cause of PVD,
Heavy smokers as young as 20-40 years old
Takayasu’s arteritis:
- pulseless disease, infla disease, occluded 1 or more branches of the aortic arch
Less common cause of PVD
Common sites of atherosclerosis lesions
Coronary arteries
Carotid bifurcation
Abd aorta
Iliac and femoral arteries
What are some s/s of atherosclerosis
Claudication Pain Skin ulceration Gangrene Impotence
What determines the extent of disability
Collateral blood flow
When demand > supply = ischemia: cramping, tiredness, pain, earnest occurs in limb
Medical treatment for atherosclerosis
- Exercise, stop smoking, ASA, control of HTN and DM,
- anti platelet therapy,
- ADP receptor antagonists
- Glycoprotein inhibitor
Surgical therapy
Stent Angioplasty Enarterectomy Thrombectomy Bypass: aortofemoral, fem-pop, axil-fem
What is the primary objective of monitoring pt
Detection MI, high risk
Arterial pressure waveform
- Anacratic limb: initial upsweep: contractility, strong LV fun
- Dicrotic limb: downstroke: reflects SVR
- Dicrotic notch: closure AV and start of diastole
Most common aneurysm and position
AAA,
95% occur below the level of the renal artery
Normal size of the aorta
Aneurysm is defined when size…
- 2-2 cm
1. 5 times the diameter of normal vessel
What is the mortality rate of aneurysm
Elective vs emergency
Elective 2-6%
Emergency 40-88%
MI is responsible for 30-70% of all fatalities after AAA repair
Overall fatality of aneurysm rupture is 70-80%
Laplace law aneurysm application is
As radius increases, wall tension increases
Larger aneurysm = greater risk of rupture
T = PR or T = PR/2
Contra for aortic reconstruction
Acute MI Intractable angina Severe pulmonary insufficiency Chronic renal insufficiency Life expectancy
What happens to blood proximal to clamp, supra celiac aorta clamp
Increased:
- venous return: preload
- intracranial blood volume
- lung blood volume
- blood volume and flow in muscles proximal to clamp
Shift of blood volume into splanchnic vasculature with infra celiac clamp
If splanchnic venous tone is high: Increased preload
If splanchnic venous tone is low: decreased venous return and preload
Aorta clamp on; what is happening?
Passive venous recoil distal to clamp
Increase catecholamines and other vasoconstrictors
Decreased venous return cause of vasoconstriction
Blood volume shifts proximally to clamp
Next depends when the clamp is placed
What does pathophysiology of aortic cross-clamping depends on?
- Level of the cross clamp: infra renal, higher - greater response
- Extent of CAD and myocardial function
- Degree of periaortic collateralization
- Blood volume and distribution
What happens proximally to clamp
Redistribution of blood volume
Everything increased except CO, which remains the same or decreases slightly
What are the causes of reactive hyperemia?
- Transient vasodilation
- Release of adenine nucleotides
- Release of vasodepressor that acts as myocardial depressant and peripheral vasodilator - decreased pre/afterload: decreased CO
Key points of declamping shock syndrome?
Hemodynamic instability
Restoring IVF b4 clamp release may help w/circulatory stability
Gradual release decrease the hemodynamic changes
What is released in response to tissue ischemia? #1
Venous endothelian
What is venous endothelian responsible for
Hemodynamic instability
Has positive inotropic effect on the heart
Vasoconstricting/dilating effects on blood vessels
Arteriosclerosis
- generalized inflammatory disorder of the arterial tree w/endothelial dysfunction
- formation of plaque that obstruct the vessel lumen/ dec distal blood flow
Plaque formation - Thrombosis - emboli - dec distal blood flow - weakening of the arterial wall - aneurysm
