What is the next step in managing a 70-year-old patient with Hypertension (HTN) and Cardiac disease, who complains of claudication after walking 100 yards in the left lower limb, and has a weak inferior popliteal pulse and non-palpable dorsalis pedis pulse?

Management of Suspected Peripheral Arterial Disease in a 70-Year-Old Patient

The next step in managing this patient with claudication and diminished pulses should be ABI measurement (option D). This is the most appropriate initial diagnostic test for confirming peripheral arterial disease (PAD) in this patient with classic symptoms and abnormal physical examination findings 1.

Clinical Assessment and Diagnosis

The patient presents with several key features suggesting PAD:

• 70 years old (high-risk age group)
• History of hypertension and cardiac disease (risk factors)
• Claudication after walking 100 yards (classic symptom)
• Abnormal pulse examination (weak popliteal pulse, absent dorsalis pedis)

These findings strongly warrant objective confirmation of PAD diagnosis through diagnostic testing.

Why ABI is the First-Line Test:

1. Guideline-Directed Approach: Current ACC/AHA guidelines explicitly recommend the ABI as the initial diagnostic test for PAD 1. It may be the only test required to establish the diagnosis and initiate appropriate therapy.

2. Simple, Non-Invasive Procedure: The ABI is a simple, non-invasive test that measures systolic blood pressures at the arms and ankles using a Doppler device 1.

3. High Diagnostic Value: An ABI <0.90 is diagnostic for PAD, regardless of symptoms 1. This test provides objective confirmation of the clinical suspicion.

4. Risk Stratification: Beyond diagnosis, the ABI provides prognostic information about cardiovascular risk, which is particularly important in this patient with existing cardiac disease 1.

Why Other Options Are Not Appropriate as First Steps:

• Vascular Doppler (Option A): While useful, duplex ultrasound is typically performed after ABI confirmation of PAD, particularly when anatomic localization is needed for potential intervention 1.

• Embolectomy (Option B): This is an invasive procedure reserved for acute limb ischemia, which this patient does not demonstrate. The patient has chronic symptoms (claudication) rather than acute limb-threatening ischemia 1.

• Conventional Angiography (Option C): This invasive procedure is typically reserved for patients in whom revascularization is being considered, after non-invasive testing has confirmed PAD 1. It should not be the first diagnostic step.

Management Algorithm After ABI Measurement:

1. If ABI < 0.90: Confirms PAD diagnosis

   • Initiate medical therapy (antiplatelet therapy, statin)
   • Consider supervised exercise program
   • Risk factor modification (smoking cessation, blood pressure control)

2. If ABI > 1.40: Suggests non-compressible vessels

   • Proceed to toe-brachial index or pulse volume recording 1

3. If ABI normal but symptoms persist:

   • Consider exercise ABI testing to unmask PAD 1

4. After PAD confirmation:

   • If symptoms are lifestyle-limiting despite medical therapy, consider anatomic imaging (duplex ultrasound, CT angiography) for potential revascularization planning 1

Common Pitfalls to Avoid:

• Skipping ABI measurement: Relying solely on symptoms and pulse examination without objective confirmation can lead to misdiagnosis.

• Premature invasive testing: Jumping to angiography before non-invasive testing increases risk without clear benefit.

• Overlooking falsely normal ABIs: In diabetic patients or those with arterial calcification, ABI may be falsely elevated, requiring additional testing like toe-brachial index 2.

• Neglecting cardiovascular risk: PAD indicates systemic atherosclerosis; these patients require comprehensive cardiovascular risk assessment and management.