Peripheral Vascular Disease Flashcards
What is the prevalence of peripheral artery disease in the adult population? What about for those over 70 or diabetic or smoker?
Adult population: 10-12 %
Old/diabetic/smokers: 20%
PAD patients have a 6 fold increase of CV death. Out of the following risk factors, which has a greatest risk increasing PAD?
Diabetes
Smoking
Lipids
Hypertension
Diabetes (4-fold increased risk)
Smoking (2-3 X)
Lipids (2 X)
Hypertension (2X)
Your patient is a 68 year old with a typical case of PAD. What would you expect the patient to have in each of the following? 1) Past Medical History 2) Risk factors 3) Physical exam
PMH: Developing symptoms of calf cramping on walking 1 block, relieved by rest
Risk factors: 50 pack years smoking, LDL 135, & diabetes
Physical exam: Bruit Left leg: absent femoral and pedal pulses Right leg: normal femoral and pedal pulses
Ok so the signs of PAD are bruits, absent pulses, muscle atrophy, leg ischemia (ulcers, gangrene, pallor of feet with elevation, rubor). But what are the symptoms they will complain of?
- Intermittent claudication (cramping, fatigue with exercise) or Ischemic pain/ ulcers/ gangrene at BOTH rest and exercise
- Pain in distal foot worsened with elevation
- Distal, painful ulcers on toes or heel
What is the ankle-brachial index (ABI)?
Its a ratio of the blood pressures at the ankle and arm
*Should be equal
If a patient has an ABI of 0.6 what condition would he have? 0.9?
< 0.9 = PAD
0.9 - 1.00 = atherosclerosis
What different factors would change arterial hemodynamics (determine blood flow in an artery with occlusive disease)?
Which would have the greatest impact?
- Perfusion pressure
- blood viscosity
- Arterial stenosis (plaque build up)
- radius *Greatest impact
- length
-Flow velocity (hemodynamic severity ^ with higher velocities)
In peripheral arterial disease you have a stenosis that causes turbulent flow and impaired endothelial function. What effect does this have downstream?
- Inability to increase flow with exercise
- mismatched O2 supply/ demand
- Reduced ABI
- Inefficient oxidation
- High oxidant stress
What are your approaches for therapy for someone with claudication?
- Prevent CV events from coronary or carotid plaque rupture (MI, stroke, vascular death)
- Improve limb symptoms, exercise performance and quality of life
- Heal ulcers and prevent limb loss from gangrene
- Treatments:
- Surgery or angioplasty improves hemodynamics
- Exercise training improves muscle metabolism
- Drugs (cilostazol) have multiple mechanisms
- What layers of the vessel have pathology in an aneurysm?
- What’s the normal width or the aorta, and 3. how would you classify an aortic aneurysm?
- Pathological expansion of all three arterial layers
- The normal aorta in an adult:
- 3 cm at its root;
- 2.5 cm mid descending thoracic aorta;
- 2 cm at the infra-renal aorta
- AAA denoted by diameter of > 3.0 cm
* Or 50% increase in size relative to proximal normal segment
What are four mechanisms by which aneurysms can form?
- Weakened aortic wall (decr. elastin/ collagen)
- Inflammation
- Proteolytic enzymes (mmp’s)
- Biomechanical stresses (turbulent flow, thrombus)
At what maximum aneurysm diameter is there a 5 year rupture rate of 25%?
a. < 4 cm
b. 4.0-4.9
c. 5.0-5.9
d. 6.0-6.9
e. >7.0
a. < 4 cm 2%
b. 4.0-4.9 3-12%
c. 5.0-5.9 25%
d. 6.0-6.9 35%
e. >7.0 75%
T/F: the majority of aneurism cases are asymptomatic and then present with sudden death?
TRUE
- 70% of patients are asymptomatic, then present with sudden death
- 30% present with abdominal discomfort or severe pain radiating to the back, then die
How are aneurysms usually found?
Then how are they diagnosed?
- Aneurysms are rarely detected by PE, and usually found through incidently while imaging for something else.
- Diagnosis:
- Plain X-ray
- Ultrasound
- Computerized tomography
- Magnetic resonance imaging
- Arteriography
- May miss it because angiography views the lumen not the arterial wall
Why is there a propensity for abdominal aortic aneurysms?
- Fewer elastic lamellae than the thoracic aorta, making it less able to accommodate decreases in elastin levels.
- Decreased vasa vasorum (perfusion) causes:
- increased vessel rigidity,
- decreased compliance,
- decreased ability to accommodate pulsatile flow.
-Pattern of blood flow: this section withstands the greatest level of oscillating blood flow and reflected pressure waves
What are four stages of Venous Thrombo Emboli progression?
