Peripheral Vascular Disease, Emergency Medicine

Basics

Description

Obstruction of ≥1 of the peripheral arteries secondary to embolism or thrombus
Caused by atherosclerosis or embolus
Patients with PAD may also have coronary artery and cerebrovascular disease.
Epidemiology:
- Risks factors (selected):
  - Age
  - Smoking
  - Diabetes
  - Hyperlipidemia
  - HTN
- Associated with morbidity and mortality from other forms of atherosclerosis (coronary artery disease, stroke)
- Complications:
  - Aneurysm
  - Thrombosis
  - Ulceration
  - Limb loss
Chronic arterial insufficiency (CAI):
- Progressive obstructing atherosclerotic disease causing subacute ischemia and pain (claudication)
- 10% develop critical leg ischemia.
Acute arterial insufficiency (AAI):
- Caused by arterial thrombosis (50%) or embolism
- Causes acute limb ischemia with signs and symptoms of the 6 Ps (below)
Atheroembolism:
- Caused by rupture or partial disruption of an atherosclerotic plaque (aorta, femoral, iliac)
- Gives rise to cholesterol emboli that shower and obstruct arteriolar networks
- May be precipitated by invasive arterial procedures such as cardiac catheterization

Etiology

Obstruction by atherosclerotic plaques (CAI)
Arterial thrombosis
Arterial emboli:
- Cardiac emboli from dysrhythmias, valvular heart disease, or cardiomyopathy (80%)
- Aneurysms
- Infection
- Tumor
- Vasculitis or foreign body
- Thrombosis of plaques from pre-existing CAI
Atheroembolism

Diagnosis

Signs and Symptoms

History

CAI:
- Claudication:
  - Aching pain in the calves (femoropopliteal occlusion) or buttocks and thighs (aortoiliac region)
  - Occurs with activity and slowly relieved by rest or dependent positioning
  - Classic claudication presents in about 1/2 of patients with PVD.
- Severe disease presents with limb pain at rest:
  - Usually starting in the foot
  - Rapidly progressive claudication or ulceration
AAI:
- Extremity pain:
  - Sudden onset
  - Gradual increase in severity
  - Starts distally and moves proximally over time
  - Decrease in intensity once ischemic sensory loss occurs
Atheroembolism:
- Complaint of cold and painful fingers or toes
- Small atherosclerotic emboli may affect both extremities.
- Usually related to recent arteriography, vascular or cardiac surgery
- Multiorgan involvement is common (renal, mesentery, skin, others)

Physical Exam
Sudden onset of pain and pallor in extremity is limb and life threatening. ‚

CAI:
- Absent or decreased peripheral pulses
- Delayed capillary refill with cool skin
- Increased venous filling time
- Bruits
- Pallor and dependent rubor of the leg
- Muscle and skin atrophy
- Thickened nails and loss of dorsal hair
- Ulcerations (especially toes or heels) or gangrene with severe disease
AAI:
- 6 Ps:
  - Pain (1st, sometimes only symptom)
  - Pallor
  - Pulselessness
  - Poikilothermic
  - Paresthesias (late finding)
  - Paralysis (late finding)
- Identification of a source of a possible embolic process is crucial (atrial fibrillation, cardiomegaly).
Atheroembolism:
- Ischemic and painful digits
- "Blue toe syndrome " ť
- Livedo reticularis

Essential Workup

CAI:
- Ankle " “brachial index (ankle systolic BP divided by higher arm systolic BP)
- Bedside test to determine whether CAI is present (see NEJM video reference)
- Ratio of <0.9 is abnormal and <0.4 " “5 indicates severe disease.
- Calcific arteries (diabetes) can have false negative ABI or elevated ABI (>1.3).
AAI:
- Physical diagnosis using the 6 Ps
- Those with acute-on-chronic arterial insufficiency tolerate limb ischemia better than those without CAI, due to well-developed collateral circulation.
Atheroembolism:
- Clinical diagnosis: Affected areas painful, tender, and may be either dusky or necrotic
- Workup may investigate source of emboli with duplex US, CT angiogram, EKG.

Diagnosis Tests & Interpretation

Lab

CBC and platelets
Electrolytes, BUN, creatinine, glucose
Coagulation studies
Creatine phosphokinase to evaluate for ischemia.
Special tests for suspected etiologies:
- Hold blood for hypercoagulable studies
- Sedimentation rate, CRP for vasculitis
- Blood cultures for endocarditis

Imaging

Doppler US:
- Visualizes both venous and arterial systems
- Identifies level of arterial occlusion, as well as thrombosis and aneurysm
- Sensitivity and specificity >80 " “90% for occlusion of vessels proximal to the popliteal vessels
Plethysmography/segmental pressure measurements:
- Uses measurements of the volume and character of blood flow to detect areas of CAI
- Less widely available than US, therefore requires an experienced technician
- Approximates US in sensitivity and specificity
Angiography:
- Determines details about the anatomy, including the level of occlusion, stenosis, and collateral flow
- Useful where the diagnosis of AAI is uncertain or before emergent bypass grafting
- Advantage is intervention (atherectomy, angioplasty, or intraluminal thrombolytics) can be done at the time of diagnosis.
CT angiogram:
- CT is useful for diagnosis of occlusive aortic disease or dissection.
- Rapidly available and reliable
- Many centers have moved to CT angiogram as the 1st-line diagnostic tool. The decision for operative or angiographic intervention is based on the CT angiogram.
- Requires contrast, therefore may not be 1st line for patients with renal insufficiency
MRI:
- Sensitive for evaluation of CAI and dissection
- Disadvantages are that MRI is time consuming and expensive.

Differential Diagnosis

Acute thrombosis or emboli
Arterial dissection
Deep venous thrombosis
Venous insufficiency
Compartment syndrome
Buerger disease
Spinal stenosis
Neuropathy
Bursitis
Arthritis
Reflex sympathetic dystrophy

Treatment

Pre-Hospital

Maintain hemodynamic stability with fluids.
Apply cardiac monitor.
Place the ischemic limb at rest and in a dependent position.
Provide oxygen if low oxygen saturation or pulmonary symptoms.

Initial Stabilization/Therapy

IV fluid bolus for hypotension
EKG, monitor, pulse oximetry
Supplemental oxygen
Pain control
Avoid temperature extremes

Ed Treatment/Procedures

CAI:
- Antiplatelet therapy with 75 or 325 mg of aspirin or clopidogrel (75 mg/day) may be used as 1st-line treatment. Dual therapy has not been shown to improve outcomes, although may be indicated in other forms of atherosclerosis.
- Other approved drugs include: Cilostazol 100 mg BID, dipyridamole 200 mg BID, pentoxifylline 400 mg TID
- Revascularization depending on the severity and location of obstruction:
  - Balloon angioplasty
  - Atherectomy
  - Bypass grafting
- Risk-factor modification:
  - Tobacco cessation
  - Aggressive management of hyperlipidemia, HTN, diabetes
  - Exercise therapy
AAI:
- Limit further clot propagation with IV heparin.
- Do not anticoagulate patients suspected of having an aortic dissection or symptomatic aneurysm.
- Emergent consultation with vascular surgery or interventional radiology:
  - To determine which diagnostic study is best to make the diagnosis
  - To begin arrangements for possible operative therapy or other intervention
  - Options for operative therapy include thrombectomy, embolectomy, angioplasty, regional arterial thrombolysis, bypass grafting.
  - Blood flow to the affected limb must be re-established within 4 " “6 hr after onset of ischemic symptoms.
- Complications of AAI include:
  - Compartment syndrome
  - Irreversible ischemia requiring amputation
  - Rhabdomyolysis, renal failure
  - Electrolyte disturbances
Atheroembolism:
- Treat conservatively if a limited amount of tissue is involved and renal function is not significantly compromised.
- No clear therapy for the ischemic digits besides supportive wound care and analgesia
- Some studies have tried corticosteroids to decrease inflammation, statins to stabilize plaque, aspirin, or dipyridamole
- Amputation for irreversibly necrotic toes
- Vascular surgeon referral within 12 " “24 hr of ED visit
- Prevent further embolic events by a thorough investigation and correction of the source of atheroemboli.

Medication

Aspirin: 81 " “325 mg/d
Cilostazol: 100 mg BID
Clopidogrel: 75 mg/d
Heparin: 80 U/kg bolus IV followed by 18 U/h IV
Pentoxifylline: 400 mg TID

Follow-Up

Disposition

Admission Criteria

All patients with AAI are admitted for evaluation and revascularization.
CAI: Consider admission for rapidly progressive claudication or ischemic pain at rest:
- To undergo heparinization and angiography to rule out an acute thrombosis
Atheroembolism admission indicated with large areas involved, significant pain, infection, or renal compromise

Discharge Criteria

Atheroembolism:
- If they have small lesions, adequate pain control, no evidence of renal compromise or superinfection, and follow-up within 24 hr
CAI:
- No evidence of rapid progression, critical leg ischemia, gangrene, or infection

Issues for Referral

CAI will need urgent referral to vascular surgery.
Atheroembolism, depending on the origin of the emboli, may need referral to vascular surgery or to cardiology.

Followup Recommendations

CAI without acute ischemia and atheroembolism with minimal involvement should have close follow-up to evaluate the extent of their disease. ‚

Additional Reading

Alonso-Coello ‚ P, Bellmunt ‚ S, McGorrian ‚ C, et al. Antithrombotic therapy in peripheral artery disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed.: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141:e669S " “e690S.
Creager ‚ MA, Kaufman ‚ JA, Conte ‚ MS. Clinical practice. Acute limb ischemia. N Engl J Med. 2012;366:2198 " “2206.
Grenon ‚ SM, Gagnon ‚ J, Hsiang ‚ Y. Video in clinical medicine. Ankle " “brachial index for assessment peripheral arterial disease. N Engl J Med. 2009;361:e40.
Norgren ‚ L, Hiatt ‚ WR, Dormandy ‚ JA, et al. Intersociety consensus for the management of peripheral arterial disease (TASC II). J Vasc Surg. 2007;45:SA5 " “S67.
Rooke ‚ TW, Hirsch ‚ AT, Misra ‚ S, et al. 2011 ACCF/AHA Focused Update of the Guideline for the Management of Patients With Peripheral Artery Disease (updating the 2005 guideline): A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2011;58:2020 " “2045.
White ‚ C. Clinical practice. Intermittent claudication. N Engl J Med. 2007;356:1241 " “1250.

Codes

ICD9

440.20 Atherosclerosis of native arteries of the extremities, unspecified
443.9 Peripheral vascular disease, unspecified
444.22 Arterial embolism and thrombosis of lower extremity
440.21 Atherosclerosis of native arteries of the extremities with intermittent claudication

ICD10

I70.209 Unsp athscl native arteries of extremities, unsp extremity
I73.9 Peripheral vascular disease, unspecified
I74.4 Embolism and thrombosis of arteries of extremities, unspecified
I70.219 Athscl native arteries of extrm w intrmt claud, unsp extrm
I74.3 Embolism and thrombosis of arteries of the lower extremities

SNOMED

400047006 peripheral vascular disease (disorder)
286959000 Peripheral arterial embolism (disorder)
51274000 Atherosclerosis of arteries of the extremities
275520000 Claudication (finding)
153911000119104 Peripheral arterial insufficiency (disorder)
233958001 Peripheral ischemia (disorder)
33591000 Thrombosis of arteries of the extremities (disorder)

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