Peripheral Artery Disease Overview

Peripheral Artery Disease (PAD)

• PAD is the most common form of peripheral vascular disease.
• It involves narrowing of arteries in the lower extremities, often due to atherosclerosis.
• PAD increases the risk of cardiovascular disease morbidity and mortality.
• PAD is underdiagnosed and undertreated worldwide.
• It's the 3rd leading cause of atherosclerotic morbidity.

Objectives

• Understand the pathophysiology of PAD.
• Identify risk factors and clinical manifestations.
• Describe diagnostic tools for PAD.
• Apply treatment principles for PAD.

Introduction

• PAD is the narrowing of lower extremity arteries due to atherosclerosis.
• Increased risk of cardiovascular morbidity and mortality.
• Underdiagnosis and undertreatment are widespread global issues.
• PAD is the 3rd leading cause of atherosclerotic morbidity.

Epidemiology

• PAD affects over 200 million people globally.
• 8-10 million Americans are affected.
• Incidence increases with age, reaching over 20% in patients over 80.
• PAD is often associated with other vascular diseases.
• Risk factors like smoking, diabetes, hypertension, high cholesterol, and impaired renal function increase PAD prevalence.

Pathophysiology

• PAD involves occlusion of arterial lumen by atherosclerotic plaques.
• Common arteries affected include femoral, popliteal, tibial, aortoiliac, carotid, vertebral, splenic, and renal arteries.
• Brachiocephalic arteries can also be affected.

Clinical Subsets of PAD

• Asymptomatic PAD (may have functional impairment).
• Chronic symptomatic PAD (claudication and other exertional leg symptoms).
• Acute limb ischemia (ALI).
• Chronic limb-threatening ischemia (CLTI).

Risk Factors

• Age
• Cigarette smoking
• Diabetes mellitus
• Hypercholesterolemia
• Hypertension
• Impaired renal function

Clinical Presentation

• PAD can present variably, ranging from no symptoms to pain and discomfort.
• Common characteristics include intermittent claudication and pain at rest in the lower extremities.
• Signs and symptoms can include pain, tightness, weakness, aching, numbness (especially in toes, feet, and lower legs), decreased or absent peripheral pulses, leg muscle atrophy, hair loss, smooth or shiny skin, coolness, thick or hardened toenails, peripheral edema, and ulceration or gangrene.

Who Should Be Screened for PAD?

• Patients aged ≥65.
• Patients aged 50-64 with risk factors for atherosclerosis, chronic kidney disease (CKD), or family history of PAD.
• Patients aged <50 with diabetes or one additional risk factor for atherosclerosis.
• Individuals with atherosclerotic disease in other vascular beds (e.g., coronary, carotid, subclavian, renal, mesenteric artery stenosis, abdominal aortic aneurysm).

Diagnosis

• Screening for PAD involves symptom history, physical exam, and diagnostic tests.
• History includes intermittent claudication, non-joint related limb pain, and use of validated questionnaires like the Edinburgh Claudication Questionnaire and Fontaine and Rutherford classification systems..
• Physical exam involves palpating lower extremity pulses, visual inspection of legs and feet, looking for signs like hair loss, shiny skin, muscle atrophy, coolness, and non-healing ulcers.

Diagnostic Tools

• Ankle-Brachial Index (ABI): Measures blood pressure in the ankle and arm to determine arterial narrowing.
• Toe-Brachial Index (TBI): Ratio of toe to brachial systolic blood pressure; used when suspect ABI may be falsely high due to stiffening of ankle arteries due to medial artery calcification (e.g., in DM and CKD).
• Magnetic Resonance Angiography (MRA).
• Computed Tomographic Angiography (CTA).
• Catheter-based angiography.

Treatment

• Goal of therapy is to optimize all modifiable risk factors, improve overall quality of life, reduce cardiovascular complications and death, and reduce the risk of limb loss.

Modifiable Risk Factors

• Hypertension (goal blood pressure < 130/80 mmHg).
• Dyslipidemia (statin therapy, LDL goal <70 mg/dL).
• Diabetes (glycemic control).
• Smoking cessation.

Antiplatelet Drug Therapy

• Aspirin.
• Clopidogrel (Plavix).

Anticoagulation

• Rivaroxaban 2.5 mg BID + Aspirin 81 mg daily for symptomatic PAD and recent revascularization.

Intermittent Claudication

• Cilostazol (Pletal) for improving symptoms and walking distance.

Guidelines Recommendations

• Based on class and level, recommended interventions and outcomes are described

Structured Exercise

• Structured exercise is recommended for symptomatic PAD patients.
• General principles include walking until significant claudication pain occurs, briefly resting until pain subsides.
• Exercise programs should be 30-45 minutes, 3 times per week for 12 weeks.

Interventional Procedures

• Percutaneous transluminal angioplasty (PTA)
• Aortofemoral bypass surgery
• Femoral-popliteal bypass surgery
• Amputation

Patient Counseling

• Monitor blood pressure, limit salt intake, quit smoking, regular foot exams, exercise, heart-healthy diets, and medication compliance.

Health Disparities & PAD Risk Amplifiers

• Factors like race, ethnicity (particularly Black, Hispanic, and American Indian individuals), geography, structural racism, social determinants of health, and chronic lower quality education all contribute to health disparities and increase the likelihood of PAD.