Endovascular Techniques

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Endovascular Basics & Access - Gateway to Vessels

Endovascular: Minimally invasive procedures within vessels.

  • Advantages: ↓morbidity, ↓hospital stay, ↓pain; local anesthesia.

  • Disadvantages: Radiation, contrast, restenosis, cost, technical skill.

  • Patient Selection: Comorbidities, vascular anatomy.

  • Access Sites:

    • Common Femoral Artery (CFA): Preferred; antegrade/retrograde.
      • 📌 Seldinger Technique: 1. Needle → 2. Wire → 3. Needle out → 4. Sheath/catheter.
    • Alternatives: Brachial, radial, popliteal. Seldinger technique steps
  • Basic Tools:

    • Needles (Seldinger); Guidewires (0.035", 0.018", 0.014"; J-tip, angled, hydrophilic, stiff); Catheters (diagnostic e.g. pigtail, guiding); Sheaths (introducer, French).
  • Imaging:

    • Fluoroscopy (C-arm), DSA, roadmapping. IVUS/OCT for detail.

⭐ Seldinger technique: cornerstone for percutaneous arterial access.

PTA & Stenting - Pipe Perfectors

  • Percutaneous Transluminal Angioplasty (PTA):
    • Mechanism: Plaque fracture, vessel stretching, controlled dissection.
    • Indications: Focal stenosis/occlusion (PVD, renal artery stenosis).
    • Balloons: Compliant (sizing), Non-compliant (high-pressure for resistant lesions).
  • Stents:
    • Indications: Post-PTA (flow-limiting dissection, elastic recoil), restenosis prevention.
    • Types:
      Stent TypeKey Feature / Drug (DES)Primary Uses
      Balloon-ExpandableHigh radial force, preciseRenal, iliac a.
      Self-ExpandingFlexible, conformableSFA, carotid a.
      BMSMechanical scaffoldGeneral use
      DESDrugs (Sirolimus/Paclitaxel); ↓neointimal hyperplasiaCoronary, PVD (high restenosis risk)
      Covered (Stent-Graft)PTFE-lined; sealsAneurysms, perforations, AVFs
  • Antiplatelet Therapy:
    • DAPT: Aspirin + Clopidogrel (or Ticagrelor/Prasugrel). Duration varies by stent/location.

⭐ Drug-eluting stents significantly reduce in-stent restenosis rates compared to bare-metal stents, particularly in smaller vessels or diabetic patients.

Specialized Tools & Aneurysm Repair - Advanced Arsenal

  • Atherectomy Devices: Plaque debulking/removal.

    • Types: Directional, rotational, orbital, laser.
    • Indications: Calcified/ostial lesions, PTA/stenting alternative.
  • Thrombectomy/Embolectomy Devices: For thrombus/embolus removal.

    • Types: Aspiration, mechanical fragmentation, rheolytic.
    • Indications: Acute limb ischemia, DVT, PE.
  • Endovascular Aneurysm Repair (EVAR): For Abdominal Aortic Aneurysm (AAA).

    • Device: Stent-graft.
    • Indications: Diameter >5.5cm, symptomatic, rapid expansion.
    • Key Anatomy: Adequate neck length/angulation, access vessel diameter.
  • Thoracic Endovascular Aortic Repair (TEVAR): For thoracic aortic aneurysms/dissections. Device: Stent-graft.

  • Endoleaks: Persistent aneurysm sac perfusion outside graft.

    • Types I-V (📌 "SEB-PT"):
      • I: Seal zone (graft ends)
      • II: Branch (retrograde flow, e.g., lumbar, IMA)
      • III: Fabric tear / Junctional separation
      • IV: Porosity (graft wall)
      • V: Endotension (sac expansion, no visible leak)

⭐ Type II endoleak, from branch vessels (e.g., lumbar artery, IMA), is the most common type following EVAR and often managed conservatively initially.

Complications & Post-Procedure - Navigating Pitfalls

  • Access Site:
    • Hematoma, pseudoaneurysm (Doppler: to-and-fro flow; Rx: compression, thrombin inj.), AV fistula, dissection, thrombosis, infection.
  • Systemic:
    • Contrast-Induced Nephropathy (CIN): Risks: CKD, DM, dehydration, high contrast volume. Prevent: Hydration, low/iso-osmolar contrast, ↓contrast volume, N-acetylcysteine.
    • Allergic reaction.
  • Procedure-Related:
    • Distal embolization ("trash foot"), vessel perforation/rupture, dissection, radiation injury.
  • Stent-Related (Long-term):
    • In-stent restenosis (neointimal hyperplasia), stent thrombosis (DAPT adherence crucial!), stent fracture, migration.
  • Post-Procedure:
    • Monitoring; surveillance imaging (Duplex USG, CT Angio for EVAR/TEVAR). Doppler ultrasound of femoral artery pseudoaneurysm

⭐ Acute stent thrombosis is a dreaded complication often linked to premature discontinuation of dual antiplatelet therapy (DAPT).

High‑Yield Points - ⚡ Biggest Takeaways

  • Seldinger technique is fundamental for vascular access.
  • Guidewires (hydrophilic, stiff) and catheters are core endovascular tools.
  • Angioplasty (PTA) dilates stenoses; stents (BMS, DES) maintain vessel patency.
  • EVAR/TEVAR is preferred for suitable aortic aneurysms over open repair.
  • Complications: access site issues (hematoma, pseudoaneurysm), embolization, contrast nephropathy.
  • Covered stents (stent-grafts) treat aneurysms, dissections, and perforations.
  • Mechanical thrombectomy is vital for acute limb ischemia and stroke management.

Practice Questions: Endovascular Techniques

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