Peripheral Vascular Disease

Basics

Description

  • Peripheral vascular disease (PVD) is characterized by the obstruction of peripheral arteries due to embolism, thrombus, or atherosclerotic plaque
  • Gradual accumulation of atherosclerotic plaque causes arterial stenosis, occlusion, and impaired tissue perfusion
  • Plaque ruptures leads to acute or acute-on-chronic ischemic events
  • The disease spectrum ranges from asymptomatic arterial narrowing to intermittent claudication and critical limb ischemia
  • Risks factors (selected):
    • Age
    • Smoking
    • Diabetes
    • Hyperlipidemia
    • HTN
  • 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 (80–85%) or embolism (14–15%)
    • Results in acute limb ischemia
    • Those with acute-on-CAI tolerate limb ischemia due to well-developed collateral circulation
  • Atheroembolism:
    • Caused by rupture or partial disruption of an atherosclerotic plaque releasing cholesterol emboli into arterioles
    • Most emboli originate in the heart
    • Most emboli occlude arteries at bifurcations, commonly in the femoral, popliteal, or iliac arteries
  • Affects ∼8–12 million people in the US
  • Strongly associated with aging; prevalence increases >20% in individuals >70 yr

Etiology

  • Obstruction by atherosclerotic plaques (CAI)
  • Arterial thrombosis
  • Arterial emboli:
    • Cardiac emboli (80%)
    • Aneurysms
    • Infection
    • Tumor
    • Vasculitis or foreign body
    • Thrombosis of plaques from preexisting CAI

Diagnosis

Signs And Symptoms

History

  • Claudication (CAI):
    • Aching calf or thigh pain with activity, exacerbated at night, and slowly relieved by rest or dependent positioning
    • Occurs in half of PVD patients
    • Progressive ischemic limb pain:
      • 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
      • 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

  • CAI:
    • Absent or decreased peripheral pulses
    • Delayed capillary refill with cool skin
    • 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)
    • Assess paralysis segmentally in the limb by isolating muscle groups (ie, holding the calf to assess intrinsic muscles of the foot)
  • Atheroembolism:
    • Ischemic and painful digits
    • “Blue-toe syndrome”
    • Livedo reticularis
ALERT

Sudden onset of pain and pallor in extremity is limb and life threatening

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
    • Calcified arteries (diabetes) can have false-negative ABI or elevated ABI (>1.3)
  • AAI:
    • Physical diagnosis using the 6 Ps
  • 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, ECHO, or MRA

Diagnostic Tests And 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 and possible infection
    • 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 the level of occlusion, stenosis, and collateral flow
    • Useful where the diagnosis of AAI is uncertain or before emergent bypass grafting
    • Therapeutic intervention (atherectomy, angioplasty, percutaneous thrombectomy, or intraluminal thrombolytics) can be performed simultaneously
  • CT angiogram:
    • Diagnosis of occlusive aortic disease or dissection
    • Rapidly available and reliable
    • Basis for the decision for operative or angiographic intervention
    • Relative contraindication in patients with renal insufficiency because of IV contrast
    • Limited spatial resolution for small vessels; digital subtraction angiography is the gold standard
  • MRA:
    • Sensitive for evaluation of CAI and dissection
    • Plaques can be identified within the vasculature
    • MRI is time consuming and expensive therefore limited 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 (ie, tumor)
  • Compartment syndrome
  • Buerger disease
  • Spinal stenosis
  • Neuropathy
  • Bursitis
  • Arthritis
  • Reflex sympathetic dystrophy

Treatment

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 or clopidogrel may be used as 1st-line treatment
    • Other drugs include: Cilostazol, pentoxifylline, and dipyridamole
    • Revascularization depending on the severity and location of obstruction:
      • Balloon angioplasty with possible stent placement
      • Atherectomy
      • Bypass grafting
  • 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 reestablished 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 twice a day
  • Clopidogrel: 75 mg PO per day
  • Heparin: 80 U/kg bolus IV followed by 18 U/kg/hr IV
  • Pentoxifylline: 400 mg PO three times a day
  • Medical optimization (antiplatelet agents, statins, control of hypertension, diabetes, cardiac and renal functions)

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
  • 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

  • Patients with CAI should have close follow-up to evaluate the extent of their disease
  • Risk-factor modification:
    • Tobacco cessation
    • Aggressive management of hyperlipidemia, HTN, diabetes
    • Exercise therapy

Additional Readings

  1. Firnhaber JM, Powell CS. Lower extremity peripheral artery disease: Diagnosis and treatment. Am Fam Physician. 2019;99(6):362–369.  [PMID:30874413]
  2. Kullo IJ, Rooke TW. Peripheral artery disease. N Engl J Med. 2016;374(9):861–871.  [PMID:26962905]
  3. Morley RL, Sharma A, Horsch AD, Hinchliffe RJ. Peripheral artery disease. BMJ. 2018;360:j5842.  [PMID:29419394]
  4. Santistevan JR. Acute limb ischemia. An emergency medicine approach. Emerg Med Clin North Am. 2017;35(4):889–909.  [PMID:28987435]

See Also (Topic, Algorithm, Electronic Media Element)

Authors

Melanie Yates

Lindsay Taylor