What are the Ankle-Brachial Index (ABI) results and recommended interventions?

From the Guidelines

The ankle-brachial index (ABI) results should guide specific interventions based on severity, with a focus on cardiovascular risk factor management, lifestyle modifications, and medical therapy to improve outcomes and reduce morbidity and mortality. According to the 2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS guideline for the management of lower extremity peripheral artery disease 1, the resting ABI is recommended to establish the diagnosis of PAD, with results categorized as abnormal (ABI ≤0.90), borderline (ABI 0.91-0.99), normal (ABI 1.00-1.40), or noncompressible (ABI >1.40). For patients with suspected PAD, the following interventions are recommended:

• For normal ABI (1.00-1.40), focus on cardiovascular risk factor management, including smoking cessation, blood pressure control, statin therapy, and antiplatelet therapy 1.
• For borderline ABI (0.91-0.99), add structured exercise programs, such as 30-45 minutes of walking, 3-5 times weekly 1.
• For mild-moderate PAD (ABI 0.5-0.79), intensify medical therapy with cilostazol 100mg twice daily for claudication symptoms and consider referral to vascular specialists 1.
• For severe PAD (ABI <0.5), immediate vascular surgery consultation is necessary, along with aggressive risk factor modification and pain management 1.
• For non-compressible vessels (ABI >1.40), alternative testing like toe-brachial index is needed 1. Regular follow-up every 3-6 months is essential to monitor disease progression and treatment effectiveness, with ABI reassessment annually or with symptom changes 1. Key considerations in managing PAD include:
• Cardiovascular risk factor management to reduce systemic atherosclerosis and cardiovascular event risk
• Lifestyle modifications, such as smoking cessation and regular exercise, to improve symptoms and outcomes
• Medical therapy, including statins, antiplatelet agents, and cilostazol, to reduce morbidity and mortality
• Referral to vascular specialists for patients with severe PAD or those who require revascularization procedures 1.

From the Research

ABI Results and Recommended Interventions

The Ankle-Brachial Index (ABI) is a useful diagnostic tool for assessing peripheral artery disease (PAD). Based on the provided studies, the following interventions are recommended for patients with PAD:

• Medical therapies, including smoking cessation, lipid-lowering drugs, optimal glucose control, and antithrombotic medications, can reduce the risk of major adverse cardiovascular events and major adverse limb events 2.
• Exercise training and cilostazol can improve walking capacity in patients with PAD 2.
• Antithrombotic therapy, such as single antiplatelet therapy (SAPT) or dual antiplatelet therapy (DAPT), can reduce the risk of ischemic cardiovascular complications in patients with PAD 3, 4.
• Rivaroxaban 2.5 mg BID in addition to aspirin can reduce the incidence of major adverse cardiovascular events and major adverse limb events in patients with PAD, without increasing life-threatening bleeding 3, 4.

Treatment Algorithms

The following treatment algorithms can be considered for patients with PAD:

• For asymptomatic PAD, there is no scientific evidence to support single antiplatelet therapy for primary prophylaxis 4.
• For symptomatic PAD, SAPT with aspirin or clopidogrel is indicated, with clopidogrel possibly being preferred over aspirin 4.
• For patients with prior myocardial infarction, DAPT with ticagrelor 60 mg BID and aspirin may be considered 4.
• For patients undergoing percutaneous peripheral interventions, at least four weeks of DAPT with aspirin and clopidogrel is recommended after infrainguinal stent implantation 4.

Duration of Antiplatelet Therapy

The optimal duration of antiplatelet therapy in patients with PAD is still unclear, with studies suggesting that longer durations of DAPT may result in decreased rates of major adverse cardiac events, major adverse limb events, and mortality, without a significant increase in severe bleeding episodes 5. However, further research is needed to determine the optimal use of DAPT in PAD patients.