Peripheral Artery Occlusive Disease

Dr.mehdi hadadzadeh

Cardiovascular surgeon

Peripheral Artery Occlusive Disease

Prevalence

Approximately 1 million Americans become symptomatic Q year

Approximately 5% of men and 2.5% of women complain of intermittent claudication by history

If asymptomatic disease is included (as determined by ABI) 13% of women and 16% of men have peripheral vascular disease

Of these only 1% have critical limb ischemia

Risk Factors

Age Male gender (over age 70 risk equalizes) DM (tend to have more distal and diffuse

disease; 7 fold increase risk of amputation) Tobacco (risk even stronger than for CAD; with

smokers experiencing IC up to 10 yrs earlier) HTN Hyperlipidemia

Prognosis

Over 5-10 yrs 70% of pt’s have no change or improve

20-30% worsen 10% require intervention 1% require amputation In patients with IC the majority of morbidity and

mortality comes from increased risk of CAD/CVD

Associated Risks (CAD/CVD)

Estimated that of those with lower extremity arterial disease at least 10% also have CVD and 28% have CAD

Of patient with LE arterial disease 75% will die of a coronary or cerebrovascular event

History

Quality (aching, numbness, weakness, fatigue) Location (calf, buttock, or thigh) Severity of pain and functional limitations Typically induced by walking and relieved by rest True claudication typically resolves in <10 minutes

after stopping activity Nocturnal pain and pain at rest are indications of more

severe disease Risk Factors

Physical Exam

Condition of skin and appendages Pulses Check for bruits Pallor during leg elevation Time for color return after leg restored to

dependent position ABI

Symptoms Intermittent claudication Rest pain Erectile dysfunction Sensorimotor impairment Tissue lossSigns Muscular atrophy Decrease hair growth Thick toenails Tissue necrosis ulcers infection Absent pulses Bruits

Atypical leg pain(functionally limited)

Classic (typical) claudication

~15%

~33%

50%Asymptomatic

Critical limb ischemia

Clinical Presentations of PAD

1%–2%

Aortoilliac Claudication of both buttoks, thighs and calves, femoral and disal pulses absent,bruits, impotence

Illiac Unilateral claudication of thigh, calf

Unilateral absence of femoral and distal pulses

femoropopliteal

Unilateral claudication in calf , femoral pulse palpable with absent unilateral distal pulses

Distal obstruction

Femoral & popliteal pulses palpable, ankle pulses absent, cluadication in calf & foot

Ankle Brachial Index (ABI)

ABI <0.9 is 99% sensitive and 99% specific for angiographically diagnosed PAD

Supine position Check systolic BP in upper extremities (using

Doppler) – use highest value Systolic BP in lower extremities – use highest

value Divide ankle SBP by brachial SBP May be falsely elevated in calcified vessels (DM)

ABI

Normal = >0.90 0.70 – 0.89 = mild disease 0.50 – 0.69 = moderate disease <0.50 = severe disease (rest pain/tissue loss)

If strongly suspect IC but WNL, can repeat following exercise (leg pressures only)

Other Noninvasive Testing

Segmental Pressure Measurements Pulse Volume Recordings Duplex Scanning MRA

Segmental Pressure Measurements

Measures SBP at multiple levels (upper and lower thigh, upper calf, ankle)

Pressure reductions between levels help to localize occlusion

Normally pressures increase as move further down the leg (>20mmHg gradient abnl)

Limited with calcified artery walls (ie: diabetics)

Pulse Volume Recordings

Pneumatic cuffs placed similarly to SPM with pulse volume recorders

Calibrated air plethysmographic wave form recording system

Instead of SBP, measure volume of blood entering the arterial segment during systole

Generates a waveform which normally has rapid systolic peak and dicrotic notch

Not limited by calcifications of vessel walls

PVR

SPM and PVR

Useful in measuring general local and severity of obstruction

Allow for objective monitoring of patient’s change over time through serial exams

Do not precisely localize disease or distinguish occlusion from severe stenosis

Pre-intervention Planning

Ultrasound—duplex scanning (also used for follow up of patency post-intervention)

MRA (non-invasive, no ionizing radiation, contrast dye; but more artifact)

Angiogram (gold standard; dx and rx in one procedure):invasive

Therapeutic Approaches:

MedicalMedical

surgicalsurgical

Medical Treatments

Risk factor reduction

Exercise

Medications

How to exercise for maximal benefit?

Greatest improvement in pain distances occurred with:

1. Exercise to near maximal pain

2. At least 3 times per week

3. Duration of at least 6 months

4. Walking as exercise mode

Medications

Vasodilators (not effective) Antiplatelet Agents

Pentoxifylline (Trental)

Cilostazol (Pletal)

Antiplatelet Agents

Strong evidence that aspirin is benefitial both in reducing progression of arterial occlusive disease and in reducing vascular death (MI, stroke)

Pentoxifylline (Trental) 400mg TID

An agent which is thought to improve erythrocyte deformability, reduce blood viscosity and decrease platelet reactivty

Effectiveness considered unknown

AHA recommends use only in cases where exercise therapy has failed or patients are unable to exercise

When to refer to vascular specialist?

Most patients can be managed with risk factor modification, exercise and pharmacotherapy

Arteriography is not necessary for diagnostic evaluation of patients with PAD and is indicated only when condition requires revascularization

Therefore, referral is indicated for:– Lifestyle limiting claudication refractory to exercise and

pharmacotherapy– Evidence of critical limb ischemia (rest pain or tissue loss)

Percutaneous Translumenal Angioplasty

High initial success rates of 90% Long-term success rates vary from 51-70% Best for stenosis (rather than occlusion), short

segment disease, larger vessels (ie: iliac), no DM, normal renal function

Bypass Surgery

Generally accepted as most effective treatment for those with debilitating PAD

In some contexts surgery appears superior (infrainguinal lesions 5 yr patency 38% for PTA and 80% with surgery)

Embolism, thrombosis & vascular injury are the causes of acute lower limb ischemia.

Emboli: The Sources of arterial emboli are :

Causes

●Cardiac (90%)

Arrhythmia (atrial fibrillation)

Valvular heart diseaes. ( MS)

Prosthetic heart valves.

Hx of myocardial infarction.

Atrial myxoma.

●Arterial source (9%)Atherosclerotic aortaAneurysm

●Other (1%)Hx of medication (oral contraceptives)

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Emboli usually impact at branching points in arterial tree, particularly at the bifurcation of the aorta, the common femoral bifurcation & popliteal trifurcation.

Sites of occlusion embloi to the lower limb:Femoral artery 45%Aorta & iliac artery 26%popliteal artery 15%tibial artery 1%

Thrombosis: Thrombosis usually occur on a pre-existing atherosclerotic lesion. Occasionally thrombosis occur on relatively normal artery

In patients with hypercoagulabale states ex:

Pt with malignancy, polycythemia

or pt taking high doses of oestrogen.

Trauma It is important to determine a history of

arterial trauma, arterial catheterization,

intra-arterial drug induced injection, limb fractures.

Clinical Features The 6 P’s :

■ Pain.

■ Pallor.

■ Pulselessness.

■Perishing cold.

■ Paraesthesia.

■ Paralysis.

Embolism:

obvious cardiac source

No hx of cluadication

Normal pulses in contralateral limb

Angiogram: minimal atherosclerotic

Few collateral

Clinical differentiation between thrombosis & embolism

Thrombosis:

No obvious cardiac source.

history of cluadication.

abnormal pulses in contralateral

limb.

Angiogram: diffuse atherosclerotic

Well developed collateral

TX:Immediately

Anticoagulant with heparin to prevent propagation of thrombus & distal thrombosis & this achieved by giving a bolus of 10 000 units of heparin intravenously & an infusion of about 1000 units of heparin per hour

Example of acute arterial embolus

“Saddle” Embolus of right iliac artery

Man Embolectomy : agement

This operation usually performed under local anaesthesia.

A groin incision is made & the common femoral artery is opened. often the clot is found in the artery a Fogarty balloon catheter is passed in turn into the proximal & distal arteries the balloon is inflated & the catheter withdrawn removing the clot.

Fogarty balloon catheter

Management Thrombolytic therapy: Percutaneous intra-arterial thrombolytic therapy.

Takes approximately 12-72 hours to dissolve the clot. Agents used: streptokinase, urokinase & tissue

plasminogen activator. Mechanism:

The convert plasminogen to plasmin which the active lytic agent.