Angiography techniques

Angiography techniques

Angiography techniques

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Angiography 101 - The Vessel Roadmap

  • Definition: An invasive diagnostic procedure using iodinated contrast and fluoroscopy (real-time X-ray) to visualize the lumen of blood vessels. Considered the gold standard for vessel mapping and intervention.
  • Core Principle (Seldinger Technique): The foundational method for safe, percutaneous vascular access. A needle punctures the vessel, a guidewire is passed through the needle, the needle is removed, and a catheter is fed over the wire.
  • Contrast Agents: Typically iodine-based solutions that are radiopaque (appear white on X-ray). ⚠️ Major risks include Contrast-Induced Nephropathy (CIN) and anaphylactoid reactions.
  • Common Access Sites:
    • Common Femoral Artery (CFA): Traditional choice, large diameter, easy to access.
    • Radial Artery: Increasingly preferred due to ↑ patient comfort post-procedure and significantly ↓ risk of bleeding complications.

Seldinger technique for arterial access

⭐ For patients with chronic kidney disease (CKD) or diabetes, the risk of Contrast-Induced Nephropathy (CIN) is significantly elevated. Pre-procedural IV hydration is the most effective preventative measure.

Technique & Access - Getting In

  • Core Method: Modified Seldinger Technique
    • 1. Needle Access: Puncture the target vessel with a hollow needle.
    • 2. Guidewire: Pass a flexible guidewire through the needle into the vessel lumen.
    • 3. Needle Removal: Withdraw the needle, leaving the guidewire in place.
    • 4. Sheath/Catheter: Thread an introducer sheath or catheter over the guidewire.
    • 5. Guidewire Removal: Remove the guidewire, leaving the sheath/catheter for access.

Microseldinger Technique Steps

  • Common Arterial Access Sites
    • Common Femoral Artery (CFA): Traditional workhorse. Puncture below the inguinal ligament to avoid retroperitoneal hemorrhage.
    • Radial Artery: Preferred for cardiac catheterization (↓bleeding, ↑patient comfort).
    • Brachial Artery: Alternative; higher risk of nerve injury and thrombosis.

Pre-procedure Check: The Allen test must be performed to confirm adequate collateral circulation from the ulnar artery before radial artery cannulation. This mitigates the risk of hand ischemia.

Contrast & Complications - The Aftermath

  • Contrast-Induced Nephropathy (CIN)

    • ⚠️ Highest risk: Pre-existing CKD (eGFR <60), diabetes, dehydration, concurrent nephrotoxins.
    • Pathophysiology: Direct tubular toxicity & renal vasoconstriction.
    • Prevention: IV hydration (isotonic saline) is key. Consider N-acetylcysteine (antioxidant).
    • Course: Serum creatinine (SCr) rises within 24-48 hrs, peaks at 3-5 days, resolves in 7-10 days.
  • Anaphylactoid/Allergic Reactions

    • Acute hypersensitivity; not a true IgE-mediated allergy.
    • Symptoms: Urticaria, angioedema, bronchospasm, shock.
    • Management: Pre-medicate high-risk patients (prior reaction) with corticosteroids + H1/H2 blockers.
  • Gadolinium Contrast (MRA)

    • ⚠️ Nephrogenic Systemic Fibrosis (NSF): Rare but severe fibrosing disease in patients with GFR <30 mL/min. Avoid gadolinium in this group.

Metformin & Contrast: Hold metformin on the day of contrast and for 48 hours after. Resume only after re-checking renal function. Risk of lactic acidosis if CIN develops.

Pathophysiology of Contrast-Induced Nephropathy

High‑Yield Points - ⚡ Biggest Takeaways

  • Seldinger technique is the fundamental method for percutaneous vascular access.
  • Digital Subtraction Angiography (DSA) provides the clearest images by subtracting pre-contrast bone and soft tissue.
  • Iodinated contrast is standard; be cautious of contrast-induced nephropathy (CIN), especially in patients with renal disease.
  • The most common complication is an access site hematoma or bleeding.
  • Gold standard for diagnosing conditions like vasculitis, aneurysms, and AVMs.
  • Catheter shape is crucial; Judkins for coronaries, Simmons for tortuous vessels.

Practice Questions: Angiography techniques

Test your understanding with these related questions

A 47-year-old woman comes to the emergency department after coughing up 2 cups of bright red blood. A CT angiogram of the chest shows active extravasation from the right bronchial artery. A coil embolization is planned to stop the bleeding. During this procedure, a catheter is first inserted into the right femoral artery. Which of the following represents the correct subsequent order of the catheter route?

1 of 5

Flashcards: Angiography techniques

1/10

_____ is a congenital lung malformation that presents as discrete, round, sharply defined and air-filled densities on CXR

TAP TO REVEAL ANSWER

_____ is a congenital lung malformation that presents as discrete, round, sharply defined and air-filled densities on CXR

Bronchogenic cyst

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