Atherosclerotic Peripheral Disease of the Lower Extremities Flashcards

1
Q

General Considerations

A

• 12% of the population of age 50 have significant ASPVD • 36% of the population of age 80 have significant ASPVD • Poiseulle’s Law

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2
Q

Poiseulle’s Law

A

• 70% stenosis • Reducing the radius by one half increases energy losses by a factor of 16 (vascular resistance) • Pulsatile flow—important for optimal organ function Example: when a kidney is perfused by steady flow instead of pulsatile flow, a reduction in urine volume and sodium excretion occurs. Pulsatile flow effects the microcirculation influencing transcapillary exchange, arteriolar tone, and lymphatic flow.

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3
Q

Risk Factors of LE Disease

A

Family History Obesity Sedentary Lifestyle Age Hypertension Hypercholesterolemia Diabetes Tobacco Abuse

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4
Q

Causes of ASPVD

A

Genetics Tobacco Abuse Hypertension Diabetes Hyperlipidemia Increased homocysteine levels Lack of exercise Diet and obesity Female Job and environment

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5
Q

Diabetic Patients and ASVPD

A

• Risk of amputation increased due to • Reduced sensation in feet • Reduced resistance to infection • Reduced arterial flow • Deformity of the foot (Charcot Joint) • Diabetics more susceptible to ischemia & infection—more likely to require amputation

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6
Q

Clinical Findings

A

Claudication- monocytes, neutrophils, free radicals, lactic acidosis Leriche Syndrome Rest Pain Ischemia, gangrene

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7
Q

The Six Ps

A

pulselessness paralysis pain pallor parasthesia poikilothermy

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8
Q

Physical Exam

A

-bruits, thrills -skin temp -cap refill -ulcers -pulse exam -monofilament testing

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9
Q

Non-invasive tests and imaging

A

Segmental limb pressures, ankle brachial indices (ABI’s), and plethysmography—waveform analysis Duplex scanning

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10
Q

Contrast Studies

A

• Aortogram with runoffs—”Gold Standard” • Cat scan angiogram • MRA with gadolinium • Aortogram or CTA with renal insufficiency patient, use 50% gadolinium/50% contrast and IV mucomyst and sodium bicarbonate

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11
Q

LEOD Diagnosis: Duplex Scanning

A

• Measures peak systolic & end‐diastolic blood velocities to estimate severity of stenosis • Fast arterial velocity (indicated by brighter colors on scan) indicates narrowing of artery

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12
Q

LEOD Diagnosis: Angiograms

A

• Definitive method of arterial diagnosis prior to selecting intervention • Provides anatomical information about lesion • Shows surrounding anatomy including branch arteries

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13
Q

Risk factor reductions

A

• Stop smoking • Diet • Cholesterol control • Hypertension control • Diabetic control • Ambulation, aerobic exercise

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14
Q

Medical Management Options

A

Coated Aspirin Clopidigrel Cilostazol Heparin, Coumadin

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15
Q

Aspirin

A

Inhibits cyclooxygenase activity which blocks prostaglandin metabolism and synthesis of thromboxane A2—stimulator of platelet aggregation • Mainly COX 1 (platelets), COX2 (inflammatory cells) 50:1

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16
Q

Clopidigrel

A

• Blocks ADP receptor P2Y12 , an extra carboxymethyl side group • 6 times more potent than Ticlid with fewer side effects • CAPRIE trial (Clopidogrel vs Aspirin in Patients at Risk of Ischemic Events) • 8.7% risk reduction in vascular death, ischemic stroke, and myocardial infarction versus aspirin

17
Q

Conservative treatment

A

• Ambulation, aerobic exercise • Platelet inhibitors—aspirin, plavix • Multivitamins • Vitamin E, 400IU daily • Vitamin C, 1000mg daily • B‐complex vitamins with B6, B12 and folic acid • Omega 3 fish oil • Cilostazol (Pletal) • Continued close observation, i.e. symptomology, physical exam, ABI, and doppler changes

18
Q

Invasive Treatment

A

• Angioplasty • Stenting • Cryoplasty • Anthrectomy devices, laser, and brachytherapy • Bypass—veins, prosthetic grafts • Endoprosthetic devices (Viabahn)

19
Q

CryoPlasty® procedure

A

– CryoPlasty = angioplasty + Cryotherapy – Nitrous oxide used to dilate balloon to 8atm & cool balloon surface temp to -10˚C – Three theoretical effects of cooling • Altered plaque response • Reduced elastic recoil • Apoptosis

20
Q

Atherectomy devices

A

– Open arteries blocked by plaque – Plaque is cut or shaved, then removed by endoscopic catheter – Procedure is common for densely calcified lesions or total occlusions

21
Q

Excimer laser

A

– Has many medical uses, including opening vessels occluded by plaque – Commonly used for total occlusions – Flexible fiber optic catheter advanced into lesion – Laser debulks plaque to recannilize vessel – Not yet FDA approved for peripheral artery intervention

22
Q

Brachytherapy

A

– High dose gamma radiation – Segmented center balloon advanced into lesion – Patient transferred to radiology oncology for procedure

23
Q

Amputation

A

Indications • Pain • Sepsis, multiple organ failure • Hygiene

24
Q

PreOp Evaluation

A

• Cardiac clearance—stress testing • Pulmonary function testing • Beta blocker protocol

25
Q

Ankle-Brachial Index

A