managing-peripheral-vascular-disease

# Managing Peripheral Vascular Disease

Guides PVD assessment with ABI interpretation and intervention referral criteria.

## Why This Skill Exists

Peripheral artery disease (PAD) affects approximately 8.5 million Americans and is a marker of systemic atherosclerosis associated with a 3–6x increased risk of cardiovascular death. The 2024 ACC/AHA Guideline on Peripheral Artery Disease provides evidence-based recommendations for diagnosis, risk stratification, medical management, and revascularization. PAD is significantly underdiagnosed — up to 50% of patients are asymptomatic, and the ankle-brachial index (ABI), the primary screening tool, is underutilized in primary care.

Progression from claudication to critical limb-threatening ischemia (CLTI) carries a 25% risk of major amputation at one year. Timely diagnosis, aggressive risk factor modification, supervised exercise therapy, and appropriate revascularization referral can prevent limb loss and reduce cardiovascular events.

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## Checkpoint A: Pre-Draft Intake (Mandatory)

1. What are the presenting symptoms — claudication (distance, location), rest pain, non-healing wounds, or asymptomatic? (default: "Symptoms not documented")
2. What is the ankle-brachial index (ABI)? (default: "ABI not performed")
3. Are pulse examinations documented (femoral, popliteal, DP, PT)? (default: "Pulses not documented")
4. What is the Rutherford or Fontaine classification? (default: "Not classified")
5. What are the cardiovascular risk factors — smoking, diabetes, hypertension, hyperlipidemia? (default: "Risk factors not assessed")
6. Is the patient currently on antiplatelet and statin therapy? (default: "Medication status unknown")
7. Has non-invasive vascular testing been performed beyond ABI (segmental pressures, duplex, CTA, MRA)? (default: "No additional imaging")
8. Are there signs of critical limb-threatening ischemia — rest pain, tissue loss, gangrene? (default: "CLTI not assessed")

### Documents to Request

- ABI measurement report (resting and post-exercise if available)
- Segmental pressure and pulse volume recording (PVR) study
- Duplex ultrasound of lower extremity arteries
- CTA or MRA of aorto-iliac and lower extremity vasculature (if intervention planned)
- Wound assessment documentation (if tissue loss present)
- Current medication list
- Lipid panel, HbA1c, renal function
- Smoking history and cessation status
- Prior vascular interventions or surgical reports

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## Step 1: Diagnosis and Severity Classification

**ABI Interpretation:**

| ABI Value | Interpretation |
|-----------|---------------|
| > 1.40 | Non-compressible (calcified vessels — common in diabetes, CKD); use TBI |
| 1.00–1.40 | Normal |
| 0.91–0.99 | Borderline; consider exercise ABI |
| 0.41–0.90 | Mild-to-moderate PAD |
| ≤ 0.40 | Severe PAD; high risk for CLTI |

**Toe-Brachial Index (TBI):** Use when ABI > 1.40 (non-compressible)
- Normal: ≥ 0.70
- Abnormal: < 0.70

**Exercise ABI:** Perform when resting ABI is borderline (0.91–0.99) and symptoms suggest PAD
- Drop in ABI ≥ 20% post-exercise = hemodynamically significant PAD

**Fontaine / Rutherford Classification:**

| Fontaine | Rutherford | Clinical | Severity |
|----------|-----------|---------|----------|
| I | 0 | Asymptomatic | Mild |
| IIa | 1 | Mild claudication (> 200 m) | Mild |
| IIb | 2–3 | Moderate-to-severe claudication | Moderate |
| III | 4 | Rest pain | Severe |
| IV | 5–6 | Tissue loss (ulceration, gangrene) | CLTI |

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## Step 2: Medical Management (All PAD Patients)

**Cardiovascular Risk Reduction (Class I for all PAD patients):**

| Intervention | Target/Agent | Evidence |
|-------------|-------------|---------|
| Antiplatelet | Aspirin 75–100 mg OR clopidogrel 75 mg daily | Class I for symptomatic PAD |
| Statin | High-intensity (atorvastatin 40–80 mg, rosuvastatin 20–40 mg) | Class I; LDL < 70 mg/dL |
| BP control | < 130/80 mmHg; ACEi/ARB preferred | Ramipril (HOPE trial) |
| Smoking cessation | Complete cessation; pharmacotherapy | Single most impactful modifiable risk factor |
| Diabetes management | HbA1c < 7%; SGLT2i if concurrent HF or CKD | Reduce microvascular and macrovascular risk |

**Antiplatelet Intensification:**
- COMPASS trial: rivaroxaban 2.5 mg BID + aspirin 100 mg daily — superior to aspirin alone for PAD patients (28% reduction in MALE, 24% reduction in MACE)
- Consider COMPASS regimen for stable PAD without high bleeding risk

**Claudication-Specific Therapies:**
- Cilostazol 100 mg BID: phosphodiesterase-3 inhibitor; increases walking distance 40–60% (contraindicated in HF)
- Supervised exercise therapy: > structured walking program (30–45 min, 3×/week, minimum 12 weeks) — Class I, comparable benefit to revascularization for claudication

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## Step 3: Non-Invasive Vascular Testing

**Segmental Pressures and Pulse Volume Recordings (PVR):**
- Pressure gradient > 20 mmHg between adjacent segments = hemodynamically significant stenosis
- PVR waveform analysis: normal (sharp systolic peak, dicrotic notch) → progressive blunting indicates proximal disease

**Duplex Ultrasound:**
- Peak systolic velocity (PSV) ratio ≥ 2.0 at a stenosis = ≥ 50% stenosis
- PSV ratio ≥ 4.0 = ≥ 75% stenosis
- Absent flow = occlusion

**CTA/MRA (Pre-Intervention Planning):**
- CTA: preferred for calcified vessels, post-stent surveillance
- MRA: preferred when avoiding contrast (renal insufficiency) or iodine allergy; may overestimate stenosis
- Document: inflow (aorto-iliac), outflow (femoropopliteal, tibial), and runoff vessels

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## Step 4: Revascularization Decision-Making

**Indications for Revascularization:**
- Lifestyle-limiting claudication refractory to ≥ 3 months supervised exercise + pharmacotherapy
- Critical limb-threatening ischemia (rest pain, tissue loss)
- Acute limb ischemia (emergent)

**CLTI WIfI Classification (Wound, Ischemia, Foot Infection):**
- Wound grade (0–3): based on ulcer depth and gangrene extent
- Ischemia grade (0–3): based on ABI, ankle pressure, TP
- Foot infection grade (0–3): based on IDSA/IWGDF criteria
- WIfI stage predicts amputation risk and revascularization benefit

**Revascularization Approach:**
- Aorto-iliac disease: endovascular first (stenting) for focal lesions; surgical bypass (aortobifemoral) for extensive disease (TASC D)
- Femoropopliteal disease: endovascular for short lesions (< 25 cm); bypass for long occlusions with good conduit (autogenous vein preferred)
- Infrapopliteal disease: endovascular preferred for CLTI; balloon angioplasty ± drug-coated balloon

**Acute Limb Ischemia (6 P's): Pain, Pallor, Pulselessness, Paresthesias, Paralysis, Poikilothermia**
- Rutherford acute classification I–III determines urgency (viable → irreversible)
- Class I–IIa: anticoagulate with heparin; plan revascularization
- Class IIb: emergent revascularization (thrombectomy, thrombolysis, or bypass)
- Class III: irreversible; consider primary amputation

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## Step 5: Surveillance and Long-Term Management

**Post-Revascularization Surveillance:**

| Intervention | Surveillance Protocol |
|-------------|---------------------|
| Endovascular (stent) | Duplex at 1, 6, 12 months, then annually |
| Surgical bypass (vein) | Duplex at 1, 3, 6, 12 months, then annually |
| Surgical bypass (prosthetic) | Duplex at 3, 6, 12 months, then annually |

**Long-Term Monitoring:**
- ABI measurement annually (or with symptom change)
- Cardiovascular risk factor reassessment at each visit
- Wound healing assessment for CLTI patients (weekly until healed)
- Foot care education and podiatric referral for diabetic patients

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## Checkpoint B: Post-Draft Alignment (Mandatory)

1. Is the ABI documented and correctly interpreted?
2. Is the severity classified by Fontaine/Rutherford?
3. Are all cardiovascular risk reduction therapies addressed?
4. Is supervised exercise therapy prescribed for claudication patients?
5. Is the revascularization decision supported by objective hemodynamic and anatomic data?

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## Quality Audit

- [ ] ABI measured and interpreted (or TBI if non-compressible)
- [ ] Exercise ABI performed for borderline resting ABI
- [ ] PAD severity classified (Fontaine/Rutherford)
- [ ] Pulse examination documented (femoral through pedal)
- [ ] Antiplatelet therapy initiated or documented
- [ ] High-intensity statin prescribed
- [ ] Smoking cessation addressed with pharmacotherapy options
- [ ] BP target < 130/80 with ACEi/ARB preferred
- [ ] Supervised exercise therapy prescribed for claudication
- [ ] Cilostazol considered (no HF contraindication)
- [ ] COMPASS regimen (low-dose rivaroxaban + aspirin) considered
- [ ] Non-invasive imaging appropriate for clinical stage
- [ ] CLTI assessed with WIfI classification if tissue loss present
- [ ] Revascularization indication and approach documented
- [ ] Surveillance protocol assigned post-intervention

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## Guidelines

1. Screen for PAD with ABI in patients ≥ 65, or ≥ 50 with diabetes or smoking history — PAD is underdiagnosed because many patients are asymptomatic.
2. A non-compressible ABI (> 1.40) does NOT rule out PAD — use toe-brachial index, which is unaffected by medial calcification.
3. Supervised exercise therapy is a Class I recommendation for claudication and should be offered before revascularization — studies show comparable improvement in walking distance.
4. Cilostazol is the only FDA-approved medication for claudication symptom relief — do not use in patients with any degree of heart failure.
5. The COMPASS trial regimen (rivaroxaban 2.5 mg BID + aspirin) should be considered for all stable PAD patients to reduce major adverse limb and cardiovascular events.
6. For CLTI, multidisciplinary limb salvage teams (vascular surgery, podiatry, wound care, endovascular) improve outcomes — avoid uncoordinated referrals.
7. Smoking cessation is the single most impactful intervention for PAD progression — document cessation counseling and pharmacotherapy at every encounter.
8. Post-revascularization duplex surveillance is essential — early detection of restenosis allows reintervention before graft/stent failure and limb loss.