Aspirin for Cardiovascular Event Prevention
This patient should be started on aspirin 75-162 mg daily for secondary prevention of cardiovascular events. 1
Rationale for Aspirin Therapy
This patient has symptomatic peripheral arterial disease (PAD), which constitutes established cardiovascular disease and therefore qualifies for secondary prevention rather than primary prevention. 1, 2
Key Evidence Supporting Aspirin Use
The American Diabetes Association (2004) provides Level A evidence that aspirin therapy (75-162 mg/day) should be used as a secondary prevention strategy in patients with diabetes who have peripheral vascular disease or claudication. 1
Aspirin has demonstrated a 30% decrease in myocardial infarction and 20% decrease in stroke across multiple clinical trials in patients with established cardiovascular disease. 1
The American College of Cardiology/American Heart Association (2011) recommends antiplatelet therapy for all symptomatic PAD patients to reduce myocardial infarction, stroke, and vascular death. 1, 2
Clopidogrel 75 mg daily is the preferred agent based on the CAPRIE trial showing 24% relative risk reduction in cardiovascular events compared to aspirin specifically in PAD patients, but aspirin 75-325 mg daily is an acceptable alternative. 2
Why Not the Other Options
Warfarin (Option B) is contraindicated in symptomatic PAD patients. The American College of Chest Physicians specifically recommends against combining antiplatelet agents with warfarin in symptomatic PAD (Grade 1B). 2 The WARSS trial showed no benefit of warfarin over aspirin in patients with large artery stenosis. 1
Atenolol (Option C) is not indicated for cardiovascular event prevention in this context. While beta-blockers are NOT contraindicated in PAD (contrary to historical belief) and are effective antihypertensives especially if coronary artery disease coexists, they are not the primary recommendation for preventing cardiovascular events. 2 Beta-blockers should be continued for at least 2 years after myocardial infarction in patients with prior MI, but this patient has no such history. 1
Enoxaparin (Option D) has no role in chronic cardiovascular event prevention for stable PAD. Anticoagulation is only recommended for acute limb ischemia with immediate systemic anticoagulation using unfractionated heparin (Grade 2C). 2
Additional Risk Factor Management Already Addressed
The patient is appropriately on atorvastatin, which is strongly indicated. All PAD patients should receive statin therapy regardless of baseline cholesterol levels, with a target LDL-C <70 mg/dL for very high-risk patients. 2, 3 The CARDS trial demonstrated that atorvastatin 10 mg daily reduced major cardiovascular events by 37% in diabetic patients without high LDL-cholesterol. 4
Supervised exercise program and smoking cessation are also correctly being addressed as first-line interventions for PAD. 3, 5
Dosing Recommendation
Start aspirin 75-162 mg daily (most commonly 81 mg in the United States). 1 This dose range has been studied in clinical trials and provides cardiovascular protection while minimizing bleeding risk. 1
Common Pitfall to Avoid
Do not withhold aspirin thinking this is "primary prevention" because the patient has diabetes. This patient has symptomatic PAD, which is established atherosclerotic cardiovascular disease requiring secondary prevention strategies. 1, 2