Challenges:
- High-risk location: Full-thickness biopsy risks aortic rupture/dissection.
- Usually diagnosed via imaging (CTA/MRI) or resected specimens (e.g., during aneurysm repair).
Biopsy Approaches:
| Method | When Used | Pros/Cons |
|---|---|---|
| Surgical (Open) | During aortic aneurysm repair | Gold standard (full-thickness sample) |
| Endovascular | Experimental (catheter-based) | Limited tissue, high fragmentation risk |
| Post-mortem | Autopsy cases | Definitive but not useful for treatment |
Recommendation:
- Avoid biopsy unless surgically resecting (e.g., aortic replacement for aneurysm).
- Intraoperative frozen section can guide repair strategy.
2. Carotid Artery Biopsy
Challenges:
- Stroke risk (embolism, dissection).
- Critical vessel: Usually managed based on imaging (CTA/MRA).
Biopsy Approaches:
| Method | When Used | Pros/Cons |
|---|---|---|
| Open Surgical | If carotid resection needed (e.g., aneurysm) | Best sample, but high-risk |
| Endovascular | Rare (high embolism risk) | Small, fragmented tissue |
| Ultrasound-guided core needle | Experimental (case reports) | Less invasive but unreliable |
Recommendation:
- Biopsy only if surgery is already planned (e.g., carotid endarterectomy for stenosis).
- Non-invasive imaging (MRI/MRA) preferred for diagnosis.
3. Renal Artery Biopsy
Challenges:
- Small vessel size → Higher stenosis/occlusion risk post-biopsy.
- Hypertension complicates healing.
Biopsy Approaches:
| Method | When Used | Pros/Cons |
|---|---|---|
| Open Surgical | During bypass/aneurysm repair | Full-thickness sample |
| Laparoscopic | Rare (high technical difficulty) | Limited access |
| Percutaneous (US/CT-guided) | Emerging (case reports) | Risk of hemorrhage/AV fistula |
Recommendation:
- Biopsy only if revascularization is needed (e.g., bypass for stenosis).
- Prefer CTA/MRA + clinical correlation for diagnosis.
4. Mesenteric/Iliac Arteries
Challenges:
- Bowel ischemia risk if complication occurs.
- Deep location makes biopsy technically difficult.
Biopsy Approaches:
| Method | When Used | Pros/Cons |
|---|---|---|
| Open (Laparotomy) | During bowel ischemia surgery | Best sample |
| Endoscopic ultrasound (EUS)-guided | Experimental | Limited data |
Recommendation:
- Biopsy only if resection is required (e.g., bowel resection for infarction).
- Imaging (CTA) usually sufficient for management.
5. Coronary Artery Biopsy
Challenges:
- Extremely high risk (myocardial infarction, dissection).
- Almost never done in living patients.
Biopsy Approaches:
| Method | When Used | Pros/Cons |
|---|---|---|
| Post-mortem | Autopsy | Definitive but not therapeutic |
| Intravascular (OCT-guided) | Case reports (experimental) | Fragmented tissue |
Recommendation:
Avoid biopsy in living patients (diagnose via IVUS/OCT imaging).
General Biopsy Guidelines for FCD
Avoid biopsy if:
- Non-invasive imaging (CTA/MRA) is diagnostic.
- High procedural risk (aorta, coronaries, carotids).
Consider biopsy only if:
- Surgery is already planned (e.g., aneurysm repair).
- Diagnosis remains uncertain after imaging.
Preferred methods:
- Open surgical biopsy (full-thickness).
- Intraoperative frozen section for immediate decisions.
Key Takeaways
- ✅ Aorta/Carotid/Coronary: Biopsy too risky—use imaging.
- ✅ Renal/Popliteal: Biopsy only if surgery is needed.
- ✅ Mesenteric/Iliac: Biopsy rare, only during resection.
- ✅ Gold standard: Full-thickness surgical biopsy when feasible.