Vascular Clamps in AV Graft Procedures
Yes, vascular clamps are routinely used during arteriovenous (AV) graft procedures to temporarily occlude blood flow in the artery and vein while creating the anastomoses. This is standard surgical technique for all vascular access procedures, though the specific guidelines focus more on outcomes than technical details of clamping.
Role of Vascular Clamps in AV Graft Creation
Standard Surgical Technique
- Vascular clamps are essential instruments for temporarily occluding the artery and vein during anastomosis creation, allowing the surgeon to construct the connections between the graft and native vessels in a bloodless field 1.
- The clamps remain in place on both vessels until the anastomoses are completed and tested for hemostasis 2, 3.
Timing of Clamp Release
- The optimal approach is to maintain clamping on both the arterial and venous sides until both anastomoses are completed, rather than releasing one clamp before finishing the second anastomosis 2, 3.
- Research demonstrates that releasing the arterial clamp before completing the venous anastomosis results in significantly higher failure rates (69% vs 20%) due to venous stasis and immediate venous thrombosis 2.
- When prolonged clamping (2-3 hours) is required, no significant difference exists between repairing the artery or vein first, as long as both clamps remain in place until all repairs are complete 3.
Technical Considerations
Anastomotic Construction
- The choice of suture technique (continuous vs interrupted) and anastomotic configuration is left to the surgeon's discretion, as current evidence shows no clear superiority of one method over another for AV graft patency or complications 1.
- Polypropylene monofilament sutures are standard for vascular anastomoses, providing long-term tensile strength with minimal tissue trauma 4.
Clamp Selection and Vessel Protection
- Modern atraumatic vascular clamps should be used to minimize endothelial injury during the procedure 5, 6.
- Vascular clips can be placed at anastomotic sites as radiographic landmarks to facilitate future interventional procedures if graft thrombosis occurs 7.
Critical Pitfalls to Avoid
- Never release the arterial clamp before completing the venous anastomosis—this creates venous stasis that dramatically increases the risk of immediate venous thrombosis 2.
- Avoid excessive clamping time when possible, as prolonged occlusion (beyond 2-3 hours) increases the risk of vessel injury and thrombosis, though the sequence of repair becomes less critical at these extended durations 3.
- Do not attempt to cannulate the graft until at least 14 days post-placement, and ideally wait 3-6 weeks to allow proper healing and tissue incorporation 1, 8.