Endarterectomy

PERIPHERAL ARTERY DISEASE 

Overview: 

 Definition: arterial stenosis or occlusion causing an imbalance of blood flow relative to muscular metabolism. 

 Epidemiology: smoking, DM, HTN, HLD, ↑age (20% prevalence >70yrs) (Lancet 2013;382:1329) Clinical Presentation and Diagnosis: 

 Symptoms: classic claudication (10-35%): reproducible exertional pain in muscles distal to occlusion; atypical leg pain (40-50%); asymptomatic (20-50%) (Circulation 2006;113:e463). Critical Limb Ischemia (CLI) (1-2%): rest pain (improved w/ hanging feet off bed or walking), ulcers at pressure points, dry gangrene, > 2-wks duration (vs. ALI). 

 Exam: arterial bruit, diminished peripheral pulses, ↓cap refill, pallor on elevation, ulcers, atrophic changes, ↓hair growth 

 ABI: Doppler US. Ratio of DP/PT (higher of the two) SBP to brachial SBP. Nl: 1.0-1.40; Borderline:0.91-0.99; Abnl ≤0.9. o Resting(R)/Post-exercise(PE): Mild: R≤0.90; Mod: R ≤0.70, PE ≤0.50; Sev: R ≤0.50, PE ≤0.15. CLI: R ≤0.40, rest pain. o If ABI abnl, obtain segmental ABI w/ pulse volume recording (PVR) to localize the disease o

 ABI ≥1.30 suggests ↓compressibility usually due to ↑calcifications (e.g., elderly, DM, ESRD). Further evaluate w/ PVR. 

 Exercise testing: if high suspicion for PAD and normal resting ABIs. 

 CTA (with distal run off), MRA, or Angiography: if considering revascularization.

Treatment: 

 Optimize cardiac risk factors (e.g., HTN, DM, HLD, weight loss), formal exercise program, high-intensity statin, smoking cessation. 

 Anti-platelet therapy: for symptomatic pts, ↓MI, CVA, vascular death. ASA 75-325mg QD or clopidogrel 75mg QD or ticagrelor 90mg BID (NEJM, 2017;376:32); vorapaxar 2.08mg QD: thrombin-receptor antagonist, ↓revascularization and hospitalizations (JACC 2016;9:2157). Avoid DAPT unless clinically indicated. 

 Rivaroxaban 2.5mg BID plus ASA decreased major adverse cardiac and limb events compared to ASA alone, but increased major bleeding w/o inc in fatal bleeding in pts w/ stable PAD (Lancet 2018;391:219) 

 Cilostazol: 100mg BID. Adjunct agent, ↑exercise capacity (Am J Cardiol 2002;90:1314). Contraindicated in HF. 

 Endovascular repair (angioplasty vs. stent) if: (1) CLI, (2) severe symptoms refractory to medical management. Acute Limb Ischemia (ALI): 

 Sudden decrease in limb perfusion threatening viability. (BMJ 2000;320:764). o Viable: no immediate threat of tissue loss; audible arterial Doppler signal, intact motor/sensory. o Threatened: salvage requires prompt intervention; no audible arterial Doppler signal, motor or sensory. 

 Etiologies: embolic (e.g., AF, endocarditis) > acute thrombosis (e.g., atherosclerosis, APS, HITT), trauma. Precipitating factors: Dehydration, hypotension, abnormal posture (i.e. kneeling), malignancy, hyperviscosity, hypercoagulability 

 Presentation: (6Ps) pain, poikilothermia, pallor, pulselessness, paresthesia (unable to sense light touch), paralysis 

 Diagnosis: Pulse (w/ Doppler) + neuro checks; Angiography (CT w/ b/l run-offs or arteriography). 

 Treatment: urgent vasc medicine and/or vasc surgery consult; anti-coagulation ± IA lytic; endovascular repair. 

 After treatment: watch for reperfusion acidosis, hyperk, myoglobinemia (ATN) and compartment syndrome (BMJ 2000;320:764)