Carotid Interposition Graft Selection: Ringed vs Non-Ringed PTFE
For carotid interposition grafts, use standard non-ringed PTFE, as external reinforcement (ringed grafts) has not been proven superior to standard wall PTFE in randomized controlled trials and offers no demonstrated benefit in patency, complications, or clinical outcomes.
Evidence-Based Recommendation
The 2020 KDOQI guidelines explicitly state that various PTFE modifications, including external reinforcement (external rings), have not been proven in RCTs to be consistently superior to standard wall 6-mm PTFE 1. This finding applies across vascular applications and extends to carotid reconstruction.
Clinical Performance of Standard PTFE in Carotid Interposition
Standard non-ringed PTFE demonstrates excellent outcomes for carotid interposition:
- Primary patency rates of 90-96% at intermediate follow-up (mean 36-50 months) 2, 3, 4
- Assisted primary patency of 97% in the largest contemporary series 3
- Perioperative stroke rates of 1.9-4.9%, comparable to standard carotid endarterectomy 2, 3, 4
- Long-term patency at 4 years of 89% with cumulative survival of 91% 5
Why Ringed PTFE Offers No Advantage
The theoretical benefits of external ring reinforcement (preventing kinking, improving flow dynamics) have not translated to clinical superiority:
- No RCT evidence supports improved patency with externally reinforced grafts versus standard PTFE 1
- No reduction in complications has been demonstrated with ring reinforcement 1
- The carotid position (relatively straight, minimal joint movement) does not require the anti-kinking properties that might theoretically benefit other anatomic locations 2, 3
Technical Considerations for Carotid Interposition
When performing carotid interposition with standard PTFE:
- Use 6-mm diameter standard wall PTFE as the established criterion standard 1, 2, 3
- Perform interposition from transected common carotid to transected internal carotid artery 2
- Consider this technique when standard endarterectomy would be technically difficult due to poor endpoint, extensive disease, or recurrent stenosis 2, 3, 4
- Expect restenosis rates of 8-12%, with patients having prior restenosis at higher risk for recurrence 4
Alternative Conduit Consideration
While the question specifically asks about PTFE type, note that autogenous vein (reversed greater saphenous vein) shows comparable results with 80% primary patency at 30 months follow-up and may be considered when available 3. However, standard non-ringed PTFE remains the most commonly used and well-validated option 2, 3, 4, 5.
Common Pitfall to Avoid
Do not assume that modifications to PTFE (rings, tapers, surface treatments) improve outcomes—the evidence consistently shows no benefit from these modifications across multiple vascular beds 1. The added cost and theoretical complexity of ringed grafts provide no clinical advantage in carotid reconstruction.