281.3 🏥 內科專科考前版

281.3.1 Mechanistic Deep Dive

281.3.1.1 Cystic Medial Degeneration

  • Loss of elastic fibers and smooth muscle in media
  • Replaced by mucoid material
  • Genetic (Marfan, Loeys-Dietz, vEDS, BAV, FTAAD)
  • Age-related in elderly
  • HTN exacerbates

281.3.1.2 TGF-β Pathway

  • Marfan + Loeys-Dietz: increased TGF-β signaling
  • Losartan blocks AT1R → ↓ TGF-β (mechanism for benefit in Marfan)
  • Multiple trials (COMPARE, MEND, AIMS) confirm benefit

281.3.1.3 Hemodynamic Stress

  • Pulse pressure + dP/dt → wall shear stress
  • β-blockers ↓ dP/dt → slower aneurysm growth
  • Esmolol fast-acting; metoprolol/atenolol oral chronic

281.3.2 Recent Trials & Updates

281.3.2.1 EVAR-1, EVAR-2 (Long-Term Follow-up)

  • EVAR ↓ 30-day mortality vs open
  • Late mortality (> 5 yr) crossover — EVAR worse due to graft complications
  • Re-intervention rate higher with EVAR (~ 20% at 5 yr)

281.3.2.2 DREAM (Dutch)

  • Similar findings to EVAR-1
  • 6-year mortality similar

281.3.2.3 OVER (VA Open vs Endovascular)

  • US trial, EVAR initial advantage, long-term equivalence

281.3.2.4 INSTEAD-XL (2013)

  • TEVAR + best medical for uncomplicated Type B
  • ↓ all-cause mortality at 5 yr
  • Suggested role for TEVAR even in stable B

281.3.2.5 ADSORB (2014)

  • TEVAR for uncomplicated B → ↓ aortic remodeling, ↓ enlargement
  • Practice shifting to consider TEVAR earlier

281.3.2.6 CLEVER (2024) — Hybrid Arch

  • Hybrid debranching + TEVAR for arch aneurysm

281.3.2.7 Surgery in Aortic Root + AV

  • Bentall: composite valve-graft (mechanical valve + tube graft)
  • David: valve-sparing root replacement (preserve native valve)
  • Yacoub: valve-sparing remodeling

281.3.2.8 Frozen Elephant Trunk

  • Hybrid open + endo for arch + descending in same procedure
  • Used in extensive disease or chronic dissection

281.3.3 High-Yield Specialist Points

281.3.3.1 Aortic Surveillance Imaging

  • Marfan: annual echo + CTA q3y if stable, q1y if growing
  • BAV: q1-2y
  • Repaired aneurysm: q1y first 5 years, then less

281.3.3.2 Aortic Diameter Indexing

  • Body surface area correction
  • Z-score in pediatric / Marfan (> 2 abnormal)
  • Useful in tall individuals

281.3.3.3 Coarctation in Adults

  • ~ 7% of CHD
  • Treatment: angioplasty + stent
  • Lifelong follow-up for re-coarctation, aneurysm
  • HTN persists in many despite repair

281.3.3.4 Aortic Spinal Cord Ischemia (TEVAR / Open)

  • 5-10% incidence
  • Anterior spinal artery from intercostal arteries T8-L1
  • Prevention: CSF drainage, MAP optimization, staged repair
  • Treatment: corticosteroids, CSF drainage, hyperoxygenation

281.3.3.5 Acute Aortic Syndrome — Risk Score (ADD-RS)

  • 3 categories: high-risk conditions, pain features, exam findings
  • 0 = low; 1 = moderate; 2-3 = high
  • Combine with D-dimer to risk stratify

281.3.3.6 IgG4-RD Aortitis

  • May mimic vasculitis
  • Steroid-responsive
  • Increased recognition

281.3.3.7 Genetic Counseling

  • All TAA < 60 yo or with FHx: gene panel
  • Affects family screening
  • Lifestyle / surgical decisions
  • Pregnancy counseling

281.3.3.8 Pregnancy in Aortopathy

  • Marfan: aortic dissection risk in pregnancy (esp 3rd trimester + postpartum)
  • Repair before pregnancy if root > 4.5 cm
  • Beta-blocker continuation
  • Monitor with echo throughout

281.3.4 Pearls

  • AAA screening: USPSTF Class B for men 65-75 smokers (one-time US)
  • AAA repair threshold: ♂ 5.5, ♀ 5.0, growth ≥ 0.5/y
  • Marfan repair: ≥ 5.0 cm root; Loeys-Dietz ≥ 4.0 cm; vEDS: avoid surgery
  • Type A dissection: EMERGENCY surgery
  • Type B dissection: medical first (esmolol + nicardipine); complicated → TEVAR
  • Losartan + β-blocker: Marfan aortic protection (COMPARE, MEND)
  • EVAR vs open: equipoise long-term; EVAR ↑ re-intervention
  • TEVAR for B: even uncomplicated may benefit (INSTEAD-XL, ADSORB)