Author:
LindsayTaylor
Sally A.Santen
Description
- Obstruction of the peripheral arteries secondary to embolism or thrombus (acute) or plaque (chronic)
- 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)
- Up to 10% develop critical leg ischemia
- Acute arterial insufficiency (AAI):
- Caused by arterial thrombosis (50%) or embolism
- Trauma (including iatrogenic)
- 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, atrial myxoma, or cardiomyopathy (80%)
- Aneurysms
- Infection
- Tumor
- Vasculitis or foreign body
- Thrombosis of plaques from pre-existing CAI
- Atheroembolism
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
- Usually exacerbated at night with relief of pain when foot is hung off the bed
- AAI:
- Extremity pain:
- Sudden onset
- Gradual increase in severity
- Starts distally and moves proximally over time
- Decrease in intensity once ischemic sensory loss occurs
- Embolism can occur proximally and move more distally in a minority of cases
- 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
- Can be related to aneurysm and /or stenotic disease of a more proximal source
- Multiorgan involvement is common (renal, mesentery, skin, others)
Physical Exam
ALERT |
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 (first, 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)
- Assess paralysis segmentally in the limb by isolating muscle groups (i.e., holding the calf to assess intrinsic muscles of the foot)
- Atheroembolism:
- Ischemic and painful digits
- “Blue-toe syndrome”
- Livedo reticularis
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Essential Workup
- CAI:
- Ankle-brachial index (ankle systolic BP divided by higher arm systolic BP)
- Formal arterial doppler
- 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-CAI 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, ECG
Diagnostic Tests & Interpretation
Lab
- CBC
- Electrolytes, BUN, creatinine, glucose
- Coagulation studies
- Creatine phosphokinase to evaluate for ischemia
- Special tests for suspected etiologies:
- Hold blood for hypercoagulable studies
- Sedimentation rate and 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 /or limb pressure to characterize the arterial perfusion
- Variable availability depending on the quality of the duplex technician as well as the equipment utilized
- 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, percutaneous thrombectomy, and /or intraluminal thrombolytics) can be done at the time of diagnosis
- Can be used to plan future open revascularization
- 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 first-line diagnostic tool. The decision for operative or angiographic intervention is based on the CT angiogram
- Requires contrast, therefore may not be first line for patients with renal insufficiency
- MRI:
- Sensitive for evaluation of CAI and dissection
- Plaques can be identified within the vasculature
- Disadvantages are that MRI is time consuming and expensive, therefore, limiting its utility in the ED
Differential Diagnosis
- Acute thrombosis or emboli
- Arterial dissection
- Deep venous thrombosis
- Venous insufficiency
- Venous aneurysm
- Popliteal entrapment syndrome
- Baker cyst
- Extrinsic mass compression (i.e., tumor)
- Compartment syndrome
- Buerger disease
- Spinal stenosis
- Neuropathy
- Bursitis
- Arthritis
- Reflex sympathetic dystrophy
Prehospital
- Maintain hemodynamic stability with fluids
- Apply cardiac monitor to assess for potential dysrhythmia
- 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
- ECG, monitor, pulse oximetry
- Supplemental oxygen
- Pain control
- Avoid temperature extremes
ED Treatment/Procedures
- CAI:
- Antiplatelet therapy with aspirin 81-325 mg/d or clopidogrel 75 mg/d may be used as first-line treatment. Dual therapy has not been shown to improve outcomes, although may be indicated in other forms of atherosclerosis
- Other drugs include: Cilostazol 100 mg b.i.d, pentoxifylline 400 mg t.i.d, and dipyridamole 200 mg b.i.d
- Revascularization depending on the severity and location of obstruction:
- Balloon angioplasty with possible stent placement
- Atherectomy
- Bypass grafting
- Risk-factor modification:
- Tobacco cessation
- Aggressive management of hyperlipidemia, HTN, diabetes
- Exercise therapy
- AAI:
- Limit further clot propagation with IV heparin 80 U/kg IV bolus → 18 U/kg/hr IV gtt
- Do not anticoagulate patients suspected of having an aortic dissection or symptomatic aneurysm
- Emergent consultation with vascular surgery or interventional specialty (radiology and /or cardiology):
- To determine which diagnostic study is best to make the diagnosis
- To begin arrangements for possible operative therapy and /or other intervention
- Options for operative therapy include percutaneous 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
- Formal arterial US
- 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 PO per day
- Cilostazol: 100 mg PO b.i.d
- Clopidogrel: 75 mg PO per day
- Heparin: 80 U/kg bolus IV followed by 18 U/kg/hr IV
- Pentoxifylline: 400 mg PO t.i.d
- Medical optimization (antiplatelet agents, statins, control of hypertension, diabetes, cardiac and renal functions)
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
Follow-up Recommendations
CAI without acute ischemia and atheroembolism with minimal involvement should have close follow-up to evaluate the extent of their disease
- Alonso-CoelloP, BellmuntS, McGorrianC, 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.
- GrenonSM, GagnonJ, HsiangY. Video in clinical medicine. Ankle-brachial index for assessment peripheral arterial disease . N Engl J Med. 2009;361:e40.
- MorleyRL, SharmaA, HorschAD, et al. Peripheral artery disease . BMJ. 2018;360:5842.
- PatelMR, ConteMS, CutlipDE, et al. Evaluation and treatment of patients with lower extremity peripheral artery disease: Consensus definitions from Peripheral Academic Research Consortium (PARC) . J Am Coll Cardiol. 2015;65:931-941.
- RookeTW, HirschAT, MisraS, 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.
See Also (Topic, Algorithm, Electronic Media Element)