Which is the most common cause of femoral artery thrombosis following femoral artery puncture for angiography?

Explanation

## Femoral Artery Thrombosis Post-Puncture ### Pathophysiology of Thrombosis **Key Point:** The most common mechanism of femoral artery thrombosis after puncture is **intimal injury with subsequent atherosclerotic plaque rupture** at the puncture site, leading to platelet activation and thrombus formation. ### Mechanism of Intimal Injury 1. **Direct needle trauma** — Puncture disrupts the intimal layer 2. **Plaque rupture** — In atherosclerotic vessels, needle entry can rupture underlying plaque 3. **Platelet aggregation** — Exposed collagen and tissue factor trigger coagulation cascade 4. **Thrombus propagation** — Local thrombosis can extend proximally or distally ### Risk Factors for Post-Puncture Thrombosis | Risk Factor | Mechanism | | --- | --- | | Atherosclerotic disease | Pre-existing plaque rupture | | Hypercholesterolaemia | Plaque burden | | Diabetes mellitus | Endothelial dysfunction | | Smoking | Intimal injury predisposition | | Prolonged catheterization | Mechanical trauma | | Small vessel calibre | Reduced flow reserve | ### Clinical Pearl **High-Yield:** Intimal injury is the **primary event** in post-puncture thrombosis. This occurs in 0.5–2% of femoral artery punctures, with higher rates in patients with pre-existing atherosclerosis or small-calibre vessels. ### Why Other Mechanisms Are Less Common - **Vasospasm** — Usually transient and self-limited; rarely causes complete thrombosis - **Catheter embolism** — Uncommon with modern catheter design; requires significant catheter fragmentation - **Haematoma compression** — May cause flow compromise but is typically managed by decompression; true thrombosis requires intimal injury **Warning:** Do not confuse **flow compromise from haematoma** (mechanical) with **thrombosis from intimal injury** (thrombotic). The latter is more common and requires anticoagulation; the former requires decompression. ### Prevention Strategies - Careful puncture technique with palpable landmarks - Appropriate catheter size (avoid oversizing) - Minimize dwell time - Maintain adequate anticoagulation during procedure - Gentle catheter manipulation [cite:Standring Anatomy 42e Ch 81; Harrison 21e Ch 297]