Peripheral arterial disease

Peripheral arterial disease

Peripheral arterial disease

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Pathophysiology - Clogged Pipes 101

Peripheral Artery Disease: Narrowed and Blocked Artery

  • Atherosclerosis is the primary cause, leading to stenosis or occlusion.
  • Major Risk Factors: Smoking (strongest), Diabetes Mellitus, Hyperlipidemia, Hypertension.
  • Process: Endothelial injury → lipid deposition (LDLs) → foam cell & plaque formation → narrowed lumen → ↓ blood flow (ischemia).
  • Most Common Sites: Superficial femoral artery (SFA) in Hunter's canal, followed by the popliteal artery.

Leriche Syndrome Triad (Aortoiliac occlusion):

  1. Bilateral hip, thigh, and buttock claudication
  2. Impotence
  3. Symmetric atrophy of the bilateral lower extremities.

Clinical Features - The Leg's Complaint

  • Intermittent Claudication: Reproducible muscle pain (calf, thigh, buttock) on exertion, promptly relieved by rest.
  • Rest Pain: Severe, nocturnal forefoot pain, relieved by dependency (hanging foot off bed). A key feature of Critical Limb Ischemia (CLI).
  • Physical Signs:
    • Shiny, atrophic skin with hair loss.
    • Dependent rubor and elevation pallor.
    • Cool skin; diminished or absent pulses.
  • Tissue Loss (Advanced Disease):
    • Arterial Ulcers: Deep, "punched-out," painful lesions on distal toes or pressure points.
    • Gangrene.

⭐ The location of arterial ulcers (e.g., tips of the toes, pressure points) is a key differentiator from venous ulcers (typically over the medial malleolus).

Diagnosis - Checking the Flow

  • Ankle-Brachial Index (ABI): Best initial, non-invasive test.
    • Calculated as $ABI = \frac{\text{Highest Ankle SBP}}{\text{Highest Brachial SBP}}$.
    • Interpretation:
      • < 0.9: Diagnostic of PAD.
      • < 0.4: Severe disease / Critical Limb Ischemia (CLI).
      • > 1.4: Calcified, non-compressible vessels (e.g., advanced age, diabetes).

⭐ An Ankle-Brachial Index (ABI) of <0.9 is the simple, non-invasive, first-line test for diagnosing PAD.

  • Imaging:
    • Doppler US: Localizes lesions.
    • CTA/MRA: Gold standard for anatomical detail before revascularization.

Ankle-Brachial Index (ABI) and PAD Severity Table

Management - Restoring the Rush

⭐ A supervised exercise program is a highly effective, first-line intervention for intermittent claudication that can improve symptoms and walking distance significantly.

  • Conservative Management

    • Risk Factor Modification: Smoking cessation is paramount. Also manage HTN, DM, HLD.
    • Supervised Exercise Therapy: Walk until near-maximal claudication pain, rest, repeat.
  • Medical Management

    • Antiplatelet Therapy: Aspirin or Clopidogrel to reduce MI/stroke risk.
    • Statins: All patients with PAD should be on a statin, regardless of LDL level.
    • Cilostazol: Phosphodiesterase inhibitor; most effective medical therapy for claudication symptoms.
  • Surgical Intervention

    • Revascularization: For limb-threatening ischemia or debilitating, refractory symptoms.
      • Percutaneous: Angioplasty ± Stenting
      • Surgical: Bypass grafting (e.g., fem-pop)
    • Amputation: For non-salvageable limbs (gangrene, intractable pain).

High-Yield Points - ⚡ Biggest Takeaways

  • Atherosclerosis of the lower extremities is the primary cause, most commonly affecting the superficial femoral artery.
  • Intermittent claudication is the hallmark symptom: reproducible leg pain with exertion that is relieved by rest.
  • An Ankle-Brachial Index (ABI) < 0.9 is the main screening and diagnostic test.
  • Cilostazol is the most effective medical therapy specifically for claudication symptoms.
  • Aspirin and statins are critical for reducing cardiovascular risk, including MI and stroke.
  • Critical limb ischemia presents as rest pain, non-healing arterial ulcers, or gangrene.

Practice Questions: Peripheral arterial disease

Test your understanding with these related questions

A 70-year-old man comes to the physician for the evaluation of pain, cramps, and tingling in his lower extremities over the past 6 months. The patient reports that the symptoms worsen with walking more than two blocks and are completely relieved by rest. Over the past 3 months, his symptoms have not improved despite his participating in supervised exercise therapy. He has type 2 diabetes mellitus. He had smoked one pack of cigarettes daily for the past 50 years, but quit 3 months ago. He does not drink alcohol. His current medications include metformin, atorvastatin, and aspirin. Examination shows loss of hair and decreased skin temperature in the lower legs. Femoral pulses are palpable; pedal pulses are absent. Which of the following is the most appropriate treatment for this patient?

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Flashcards: Peripheral arterial disease

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Guillain-Barre syndrome is associated with _____ DTRs beginning in the lower extremities

TAP TO REVEAL ANSWER

Guillain-Barre syndrome is associated with _____ DTRs beginning in the lower extremities

decreased

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