273.3 🏥 內科專科考前版

273.3.1 Mechanistic Deep Dive

273.3.1.1 Vulnerable Plaque

  • Thin-cap fibroatheroma (TCFA): cap < 65 ÎŒm + large lipid core
  • Detected by OCT (gold standard) or IVUS-NIRS
  • PROSPECT, PROSPECT-ABSORB trials — TCFA + plaque burden ↑ MACE
  • PREVENT trial 2024 — preemptive PCI of non-flow-limiting vulnerable plaque reduced MACE (CTO + IVUS-guided)

273.3.1.2 Plaque Erosion

  • More common in young women, smokers
  • Endothelial denudation without disrupted cap
  • EROSION trial: conservative (antithrombotic without stent) feasible if OCT-confirmed erosion

273.3.1.3 Microcirculatory Injury

  • “No-reflow” phenomenon during PCI
  • Distal embolization, microvascular obstruction
  • MVO on CMR predicts adverse outcomes

273.3.2 Recent Trials & Updates

273.3.2.1 ESC 2023 NSTE-ACS Update

  • hs-cTn 0/1h preferred algorithm
  • Routine invasive < 24h for high-risk (GRACE > 140)
  • Selective invasive acceptable for low-risk
  • Ticagrelor preferred over clopidogrel
  • Pre-treatment with P2Y12 before angio = NOT routinely recommended (ISAR-REACT 5 + DUBIUS)

273.3.2.2 ISAR-REACT 5 (2019)

  • Prasugrel vs ticagrelor in ACS
  • Prasugrel reduced MACE (9.3% vs 6.9%)
  • Bleeding similar
  • 2024 update: prasugrel may be slightly preferred in NSTEMI-PCI

273.3.2.3 MASTER DAPT (2021)

  • 1 month DAPT vs 12 months in HBR after PCI
  • 1 month non-inferior for ischemia, ↓ bleeding
  • Foundation for shortened DAPT in HBR

273.3.2.4 TWILIGHT (2019)

  • After 3 mo DAPT, ticagrelor monotherapy (drop ASA)
  • Reduced bleeding without ↑ ischemia
  • New paradigm: ASA-free maintenance with potent P2Y12

273.3.2.5 PROSPECT-ABSORB (2020)

  • Preemptive PCI of non-flow-limiting vulnerable plaques (TCFA + plaque burden > 70%)
  • Bioresorbable scaffold + medical therapy
  • Reduced clinical events at 1 year

273.3.2.6 Targeted Therapies — Lipid

  • PCSK9 inhibitors (evolocumab, alirocumab): FOURIER (2017), ODYSSEY OUTCOMES (2018) — ↓ MACE
  • Inclisiran (siRNA): ORION trials, q6mo dosing
  • Bempedoic acid: CLEAR Outcomes (2023) — ↓ MACE in statin-intolerant
  • Lp(a)-lowering (pelacarsen, olpasiran): ongoing trials

273.3.2.7 Anti-Inflammatory

  • CANTOS: canakinumab (anti-IL-1β) ↓ MACE in post-MI + CRP elevation
  • COLCOT (2019): colchicine 0.5 mg/d ↓ MACE post-MI
  • LoDoCo2 (2020): similar in CCS
  • 2023 AHA/ACC IIa for high-risk

273.3.3 High-Yield Specialist Points

273.3.3.1 Complete vs Culprit-Only Revasc

  • COMPLETE trial (2019): STEMI multi-vessel, complete revasc reduced MACE
  • NSTE-ACS: less data, but tend toward complete revasc in stable patients
  • Staged PCI common

273.3.3.2 FFR-Guided in NSTE-ACS

  • FAMOUS-NSTEMI: FFR led to changes in management in 22%
  • FUTURE trial: did not show benefit (stopped early)
  • FFR for multivessel disease in stable patients OK

273.3.3.3 Type 2 MI Management

  • Identify and treat trigger (anemia, sepsis, hypertensive crisis)
  • Statin + ASA may still benefit
  • Routine cath usually NOT indicated unless underlying CAD suspected
  • Cardiology consult for risk stratification

273.3.3.4 MINOCA Workup

  • Definition: MI with < 50% stenosis on cath
  • ~ 6-15% of all MI
  • Workup: OCT/IVUS, CMR, ergonovine if suspect spasm
  • Causes: SCAD, vasospasm, embolism, takotsubo, myocarditis, supply-demand
  • Tailor therapy to etiology

273.3.3.5 Sex Differences

  • Women with NSTE-ACS: more atypical, delayed presentation, more MINOCA, more SCAD
  • Worse outcomes if delayed reperfusion
  • Bleeding risk higher
  • Microvascular dysfunction more common

273.3.3.6 Antithrombotic in CKD

  • Dose-adjust enoxaparin (1 mg/kg q24h if CrCl < 30)
  • Fondaparinux contraindicated if CrCl < 20
  • Ticagrelor preferred in CKD (no renal adjustment)
  • Bivalirudin can reduce bleeding in CKD

273.3.4 Pearls

  • ESC 2023 dropped routine pre-treatment with P2Y12 inhibitor before angiography (except STEMI)
  • 0/1h hs-cTn with low-risk clinical features → rapid discharge possible
  • Wellens syndrome = critical LAD; do NOT stress test → straight to cath
  • De Winter T waves = STEMI equivalent in some literature
  • aVR ST elevation + diffuse ST↓ → don’t miss LM/3VD
  • Ticagrelor vs prasugrel: prasugrel marginally better (ISAR-REACT 5) but contraindications matter (prior stroke, > 75, < 60 kg)
  • MASTER DAPT / TWILIGHT define modern short-DAPT strategies
  • Plaque erosion is increasingly recognized — conservative therapy (EROSION trial) being studied