280.3 🏥 內科專科考前版

280.3.1 Mechanistic Deep Dive

280.3.1.1 Atherosclerosis in Peripheral vs Coronary

  • Similar pathology (lipid + inflammation)
  • Larger size of plaque relative to lumen
  • More calcification (esp DM)
  • Distal disease in DM (tibial)
  • Aortoiliac in younger non-DM smokers

280.3.1.2 Collateral Circulation

  • Develops chronically → reduces severity of symptoms
  • Exercise + cilostazol may augment
  • VEGF, FGF therapeutic targets (mostly disappointing trials)

280.3.1.3 Endothelial Function

  • ↓ NO bioavailability
  • Inflammatory cytokines (IL-6, TNF)
  • Statin restoration of endothelial function

280.3.2 Recent Trials & Updates

280.3.2.1 COMPASS (2017)

  • N = 27,395 stable CAD/PAD
  • Rivaroxaban 2.5 BID + ASA 100 vs ASA alone vs rivaroxaban alone
  • Combo arm: ↓ MACE 24%, ↓ MALE 46%, ↑ bleeding 70%
  • Net clinical benefit favorable
  • Established rivaroxaban + ASA standard for high-risk PAD/CAD

280.3.2.2 VOYAGER PAD (2020)

  • N = 6564 PAD post-revascularization
  • Rivaroxaban 2.5 BID + ASA vs ASA
  • ↓ MALE, ↓ amputation, ↓ MACE
  • Class IIa post-revascularization

280.3.2.3 BEST-CLI (2022)

  • N = 1830 CLTI; surgery vs endovascular
  • Cohort 1 (GSV available): surgery ↓ MALE 32% vs endo
  • Cohort 2 (no GSV): surgery = endo
  • Implications: GSV is best conduit; consider surgery first if available
  • Real-world: combined approach common (endo first, surgery later if fails)

280.3.2.4 BASIL-2 (2023)

  • Best vein vs endo-first strategy in CLTI
  • Endo-first competitive; surgery best for younger fit + GSV

280.3.2.5 CASPAR (2010 — Reminder)

  • ASA + clopidogrel post-bypass with prosthetic graft → benefit
  • Class IIa indication

280.3.2.6 Cardiometabolic Trials

  • EMPA-REG: empagliflozin in DM + CV disease
  • CANVAS: canagliflozin showed possible ↑ amputation risk (signal questioned later)
  • EMPEROR / DECLARE / DAPA-MI: SGLT2i benefit
  • LEADER, REWIND, SUSTAIN-6: GLP-1 RA benefit; semaglutide/liraglutide

280.3.3 High-Yield Specialist Points

280.3.3.1 Endovascular Therapy Modalities

  • PTA: plain balloon angioplasty
  • DES: drug-eluting stent (paclitaxel, sirolimus)
  • DCB: drug-coated balloon (paclitaxel; Zilver PTX, IN.PACT Admiral)
  • Atherectomy: directional, rotational, laser (for calcified)
  • Endograft: covered stents for aneurysmal
  • Vessel prep: lithotripsy (Shockwave), IVUS-guided
  • Drug-eluting bioresorbable scaffold — limited use

280.3.3.2 Surgical Conduits

  • Best: single-segment GSV
  • Alternative: short saphenous, arm vein, cryopreserved cadaveric vein
  • Last: prosthetic PTFE (often Heparin-bonded)
  • Patency: GSV > prosthetic
  • 5-year primary patency: ~ 70% GSV, ~ 30-40% PTFE distally

280.3.3.3 Wound Care in CLTI

  • Multidisciplinary diabetic foot team
  • Off-loading, debridement, antibiotics
  • TCC (total contact casting) for plantar ulcers
  • Negative pressure wound therapy (VAC)
  • Hyperbaric O₂ (selected)
  • Skin substitutes (Apligraf, Dermagraft)
  • Toe amputation, TMA, BKA, AKA

280.3.3.4 Vascular Stenting Pearls (Aorto-Iliac)

  • High patency rates (~ 90% at 5 yr)
  • Stent placement for moderate-severe lesions
  • Re-stenosis treated with re-intervention

280.3.3.5 Femoro-Popliteal Stenting

  • Lower patency (~ 60-70% at 1 yr)
  • DCB / DES improved
  • Watch for in-stent restenosis

280.3.3.6 Below-the-Knee / Tibial Disease

  • Common in DM
  • PTA primary; DCB / DES emerging
  • Best vein bypass for CLTI

280.3.3.7 Cardiovascular Co-Existence

  • 70-90% of PAD has CAD
  • 30-50% has cerebrovascular disease
  • Polyvascular workup justified

280.3.3.8 Cardiovascular Mortality

  • PAD = high-risk CAD equivalent
  • 5-yr mortality 25% (similar to colon cancer)
  • ABI is independent predictor

280.3.3.9 Spinal Stenosis vs Vascular Claudication

  • Spinal: standing/walking, relieved by sitting/leaning forward (shopping cart sign)
  • Vascular: walking only, relieved by standing still
  • Treatment: vascular = revasc; spinal = decompression
  • Combined exists (“pseudo-claudication”)

280.3.4 Pearls

  • ABI ≀ 0.90 = PAD; > 1.40 = non-compressible (DM/CKD) → use TBI
  • CLTI: rest pain ≥ 2 wk OR ulcer/gangrene + ABI < 0.40 → URGENT revasc
  • ALI 6 Ps: pain, pallor, pulselessness, paresthesias, paralysis, poikilothermia
  • COMPASS + VOYAGER: rivaroxaban 2.5 BID + ASA = standard for high-risk PAD
  • BEST-CLI 2022: GSV bypass first if available; endo if no GSV
  • Cilostazol AVOID in HFrEF
  • Smoking cessation = single best intervention — reduces MACE 30%+
  • 5-yr mortality 25%: PAD is a polyvascular disease marker