Lower extremity arterial disease

Atherosclerosis

Intimal thickening, calcification and loss of wall elasticity

Hardening of the arteries

Most common sites:

• #1 SFA in adductor canal

• #2 CFA bifurcation

• Calf vessels and other vessel origins

Most common cause of arterial occlusive disease

Atherosclerosis obliterans

Atherosclerosis obliterans

Atherosclerotic changes produce progressive obstruction

Accumulation of lipids in intima which cause narrowing

Usually affects extremities in a diffuse manner but increase incidence in popliteal and calf arteries

Focal stenosis and diffuse stenosis can coexist

Symptoms usually are exacerbated with exercise and relived with resting in dependent position

Arteritis

Inflammation of the artery walls causing flow stasis with thrombus formation

Usually affects peroneal arteries, posterior and anterior tibial arteries and smaller distal arteries/capillaries

Thromboangitis

Refers to diffuse inflammation of the intimal wall layer

Kawasaki disease

Affects small to medium arteries

CORONARY ARTERIES most commonly affected; causes dilatation and potential aneurysm formation

Usually seen in pediatric pts age 2-5yrs

More common in Japanese

Buerger disease/Thromboangitis obliterans

Occlusive disease of SMALL to MEDIUM size arteries caused by inflammation of arterial wall and surrounding connective tissue

Digital, plantar, tibial, peroneal and ulnar arteries

Acute onset in plantar or palmar arteries then moves centrally

ALWAYS BILATERAL but can affect one side more than the other

3 of 4 extremities affected

MONOphasic waveforms by Doppler and PPG

Buerger disease/Thromboangitis obliterans is most commonly seen in

Men smokers age 20-30yrs

Buerger disease/Thromboangitis obliterans is associated with:

Collagen disease (lupus), ischemic rest pain and distal ulcerations in the foot/digits/hand

In-step claudication

Corkscrew collateral formation is a sign of:

Buerger disease/Thromboangitis obliterans

Takayasu arteritis

Presents as hypertrophic areas of inflamed tissue usually found in the Aorta and its Branches

90% involve the subclavian arteries

Over half the cases involve the CCA

Can also affect renal arteries

Takayasu arteritis is associated with:

Supraclavicular stenosis and aortic coarctation

Takayasu arteritis Most commons

Most commonly seen in young females (20-40trs)

More common in asia and india than US

Takayasu arteritis symptoms

Absence of peripheral pulse, asymmetric brachial blood pressures, amaurosis fugax, hemiparesis, diplopia, vertigo, upper extremity claudication

Takayasu arteritis USA

Presents similar to stenosis

Clinical exam important for differentiation from atherosclerotic disease

Increased PSV and diastolic flow

2D appearance shows more diffuse involvement and more homogeneous thickening of the vessel walls than seen with atheroma formation

Giant cell arteritis

Presents in the CRANIAL arteries, but can be seen in the extremities

Blood tests are performed to measure the erythrocyte sedimentation rate

Measure C-reactive protein (CPR)

Asymmetric brachial blood pressures seen in pts with arteritis in extremities

Treated with corticosteroids, like prednisone

Symptoms of giant cell arteritis

Pain, and/or stiffness in the neck, jaw claudication, and visual disturbances

Giant cell arteritis is most commonly seen in

Women in their 70-80s

USA Giant cell arteritis

Causes diffuse or focal thickening of the muscle layer

May see increased vascularity in the wall of the inflamed segment

Halo sign - ring of thickened vessel wall tissue surrounding the vessel

Increased resistance to flow

Doppler similar to stenosis

Surgical repair is recommended for aneurysms in the extremity that exceed:

2.5-3cm in diameter

Surgical repair is recommended for aneurysms in the aorta that exceed:

5.5cm in diameter

Most common complication of peripheral artery aneurysms

Embolization

Embolization

Obstruction of a vessel by a foreign substance, such as plaque or thrombus

Most arterial emboli are from a cardiac source

Embolic material ledges in distal artery causing ischemia/necrosis

Air bubble can also be harmful embolism

Most common cardiac abnormality associated with embolization

Atrial fibrillation

Other causes of embolization

Thrombus in aneurysm, arteritis, ulcerated atherosclerotic lesions, some angioplasty procedures

Blue tow syndrome

Discoloration of the digits caused by acute ischemia

Caused by small pieces of plaque or thrombus breaking loose from a more proximal site

Commonly seen in pts with AAA or after a recent angiography procedure

If blue toes are noted during a LEA Duplex exam, an aortic evaluation should also be performed

Pseudoaneurysms are typically caused by

Trauma or invasive procedures

Pseudoaneurysms

Can be iatrogenic

The groin is the most common location for a pseudo

Incidence is INCREASING due to increased numbers of invasive procedures

Blood escapes all 3 layers of the arterial wall into the surrounding tissues and is encapsulated within the tissues

A connection is made through a neck or stalk

Treated by compression or thrombin injection

Anticoagulant therapy should be discontinued

Neck/stalk should be measured

Smaller pseudos can clot spontaneously

Primary symptoms of a Pseudoaneurysms

Palpable, pulsatile mass and a bruit

Contraindications for US guided compression therapy for a pseudo

Pt unable to tolerate procedure due to pain

Infection at the puncture site and surrounding tissues

Diameter >4cm

Stalk diameter >5mm

Present for more than 1 mo

Pts on anticoagulant therapy (must be stopped before treatment)

Contraindications for thrombin injection for pseudo

Small diameter

Indefinable neck/stalk

Associated AVF

Current anticoagulant therapy

USA Pseudoaneurysms

Rounded anechoic structure adjacent to main artery

Measure size of body in 2 planes

Measure diameter of neck at widest point

Color demonstrates turbulent flow → Ying-yang sign

High resistance to and fro flow in stalk

Use PPG to monitor changes with compression

Larger stalk Pseudoaneurysms can take longer than an hour of compression before treatment works

Compression performed in __________ intervals with a re-evaluation of flow after each compression interval

10 one-minute

AVM

Congenital connection between the arterioles and venules (lack of capillary bed)

Has multiple connections and surrounding venous collaterals and dilated veins

AVMS are seen anywhere but COMMONLY in brain, kidney, uterus, pelvis

Vein of Galen is seen in fetal evals

Causes increased volume of flow in the venous system with pulsatility and turbulence

Reduces resistance in the arterial inflow and increases diastolic flow

Large or chronic AV connections can lead to heart failure

AVF is a DIRECT connection between the arterial and venous systems caused by

Trauma or vascular procedure; usually a single connection and NO surrounding collaterals due to acute cause

Traumatic AVF

Can be a complication of an invasive procedure, MOST COMMONLY right heart catheterization

Groin puncture can cause an AF fistula between femoral vessels

Results in high velocity turbulent flow through the tract

Flow decreases in velocity and pulsatility as it enters the venous puncture site into vein

Venous flow proximal to an AV fistula becomes PULSATILE and turbulent due to the inflow of the arterial flow distally

Arterial flow proximal to AV fistula will be low resistance; pressure will decrease in the artery DISTAL to the fistula

If the AV fistula is close to the heart…

Cardiac failure can occur due to increase in venous return with less O2 blood flow reaching distal locations

Larger diameter fistulas and shorter fistulas offer ___________ to the arterial flow

Less resistance

Small diameter fistulas and fistulas with long tract offer more _____________ to the arterial flow

Resistance

Popliteal entrapment

Compression of the artery by the medial head of the gastrocnemius muscle

Commonly found in runners and athletes

Can cause numbness and paresthesia of the foot

About 30% of cases are bilateral

PPG eval can be used to assess with Extension/Flexion of foot

Most common cause of unilateral claudication in young pts

Popliteal entrapment

PW/CW Doppler eval of popliteal entrapment

Place pt in decubitus position with affected side up

obtain resting 2D images of the pop artery diameter in the trans view

Obtain Doppler waveforms

Ask pt to hyperextend leg and flex and hold foot, repeat diameter measurements

The vessel diameter will be reduced and the waveform will demonstrate reduced or absent flow

PPG eval of popliteal entrapment

Place pt in decubitus position with the affected side up

Place sensor on the great toe

Record at baseline tracing at rest

Ask pt to hyperextend leg and flex and hold the foot

Pulse diminishes when calf contracts

Compartment syndrome

Increased pressure in an osteofascial compartment that prevents blood flow in and out of tissues

Can lead to muscle and nerve damage and problems with blood flow

Can be considered a critical finding to prevent muscle and nerve damage

Compartment syndrome is most commonly an acute onset and associated with

Broken leg or arm

Anterior compartment syndrome

Treated with fasciotomy which is a procedure where the fascia is cut to relieve tension or pressure

Acute compartment syndrome

Medical emergency; it is usually caused by a severe injury; without intervention, it can lead to permanent muscle damage

Chronic compartment syndrome

Known as exertional compartment syndrome

NOT a medical emergency; usually related to athletic exertion; stopping the exertion usually clears up the problem

Risk factors for acute compartment syndrome

Broken bone

Large bruise

Re-established blood flow after surgical intervention

Crushing injuries

Anabolic steroid use

Constricting bandages and casts

Symptoms of compartment syndrome

Acute onset of persistent deep ache in an arm or leg

Pain that seems greater than expected for the severity of the injury

Numbness, pins and needles, or electricity-like pain in the limb

Swelling and edema

Skin muscle tightening

USA compartment syndrome

Similar to hematoma but within space between muscles/structures

Adventitial cysts

Rare condition

Collection of mucinous material within the adventitial wall layer of the affected vessel

Predominately affects PERIPHERAL arteries

No systemic vascular disease

Can cause lower extremity pain

Usually presents as multiple anechoic or hypoechoic areas within the wall

No blood flow is detected in the areas

Can cause compression and narrowing of vessel lumen

Adventitial cysts are most commonly in

The pop artery in young to middle aged men

Adventitial cysts

What is the most common location for atherosclerosis formation in the lower extremities?

Distal femoral artery

What correctly describes buergers disease

Associated with heavy smoking

Inflammation of the smaller vessels of the calves, forearms, hands, feet

Always BILATERAL

Which of the following describes a difference between Takayasu arteritis and Buerger disease?

Takayasu arteritis affects the aortic arch, CCA and subclavian arteries, while buerger disease affects small vessels

If the pts chart demonstrates recent lab testing for the erythrocyte sedimentation rate and C-reactive protein, what does the physician suspect is the cause of the pt’s symptoms?

Giant cell arteritis

A popliteal aneurysm is diagnosed with focal dilation when the diameter exceeds:

1cm

You are performing a lower extremity arterial duplex and identify 3 toes on a pt’s foot that are blue and discolored. What other ultrasound exam should be performed for this Pt?

Abdominal aortic duplex

Pseudoaneurysm involves rupture of ____________ of the arterial wall

The intima, media and externa layers

Why is it important to measure the stalk diameter of a pseudo aneurysm

To determine if compression or thrombin injection should be used for treatment

Difference between and AVF and AVM

AVM is a congenital defect and has multiple AV connections found in the brain, kidneys, or uterus. An AVF is a acquired defect that has a SINGLE connection found in the groin or upper extremity

What causes popliteal entrapment syndrome?

Compression of the popliteal artery by the head of the gastrocnemius muscle

What procedure is performed to treat anterior compartment syndrome

Fasciotomy

What are critical findings?

Pseudo, anterior compartment syndrome, and dissection

What sonographic sign is associated with adventitial cyst formation

Scimitar