Management of Mild to Moderate Decreases in Ankle-Brachial Index Bilaterally
Patients with mild to moderate decreases in ankle-brachial index (ABI) bilaterally should receive comprehensive medical therapy including antiplatelet therapy, statin medication, and lifestyle modifications to reduce cardiovascular risk and prevent disease progression. 1
Risk Assessment and Diagnosis
- ABI values between 0.91-0.99 are considered borderline, while values ≤0.90 indicate abnormal results and confirm the diagnosis of peripheral artery disease (PAD) 1
- Patients with mild to moderate decreases in ABI are at increased risk for myocardial infarction, stroke, and cardiovascular death, even when asymptomatic 2
- If ABI results are normal (0.91-1.40) but symptoms persist, exercise treadmill ABI testing should be performed to evaluate for PAD 1, 3
- Consider toe-brachial index (TBI) measurement if ABI is normal but clinical suspicion remains high, as approximately 18.7% of patients with normal ABI (0.9-1.3) may have a toe pressure <50 mm Hg indicating underlying PAD 4
Pharmacological Management
Antiplatelet Therapy
- In asymptomatic patients with ABI ≤0.90, antiplatelet therapy is reasonable to reduce the risk of MI, stroke, or vascular death 1
- Options include:
- For patients with symptomatic PAD, low-dose rivaroxaban (2.5 mg twice daily) combined with low-dose aspirin is effective to reduce the risk of major adverse cardiovascular events (MACE) and major adverse limb events (MALE) 1
Lipid Management
- Statin therapy is indicated for all patients with PAD regardless of baseline lipid levels 1, 5
- High-intensity statin therapy should be prescribed to achieve maximum cardiovascular risk reduction 1
- For patients on maximally tolerated statin therapy with LDL-C ≥70 mg/dL, consider adding ezetimibe or PCSK9 inhibitor therapy 1
Blood Pressure Management
- Antihypertensive therapy should be administered to patients with hypertension and PAD to reduce the risk of MI, stroke, heart failure, and cardiovascular death 1
- Angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers are effective to reduce cardiovascular ischemic events in patients with PAD 1
Lifestyle Modifications
- Smoking cessation is critical for all patients who smoke, as it significantly impacts disease progression and cardiovascular outcomes 1, 5
- Assist patients in developing a quit plan including pharmacotherapy (varenicline, bupropion, and/or nicotine replacement therapy) 1
- A supervised exercise program is recommended for patients with claudication symptoms 1, 5
- Exercise should be performed for 30-45 minutes, at least 3 times weekly for a minimum of 12 weeks 1
- For patients with lifestyle-limiting claudication, consider cilostazol (100 mg twice daily) to improve symptoms and increase walking distance 1
Follow-up and Monitoring
- Regular follow-up visits at least annually to monitor for development of leg, coronary, and cerebrovascular ischemic symptoms 1
- Periodic ABI measurement to assess for disease progression 5
- Consider duplex ultrasound surveillance in patients with identified atherosclerotic plaques 5
Special Considerations
- Anticoagulation with warfarin is not recommended for PAD unless there are other specific indications 1, 5
- For patients with normal ABI but persistent symptoms, consider alternative diagnoses or additional testing such as exercise ABI or toe pressure measurements 1, 4
- Patients with mild to moderate PAD should be screened for abdominal aortic aneurysm with duplex ultrasound 1
Common Pitfalls to Avoid
- Neglecting asymptomatic patients with abnormal ABI, as they remain at high cardiovascular risk despite lack of symptoms 6
- Relying solely on resting ABI in symptomatic patients with normal results; exercise ABI testing increases diagnostic sensitivity 3
- Failing to address modifiable cardiovascular risk factors in patients with mild PAD 5, 6
- Undertreatment with appropriate medical therapy, which is common in PAD patients compared to those with other cardiovascular diseases 1