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The influence of patent branches on in situ vein graft haemodynamics
B R Gwynn1, C P Shearman, M H Simms
1Department of Vascular Surgery, Selly Oak Hospital, Birmingham, U.K.
Insights
Preserving open graft branches during femoro-distal bypass surgery can negatively impact blood flow. Ligation of these arteriovenous fistulae is recommended to improve outcomes in arterial bypass procedures.
Area of Science:
- Vascular Surgery
- Hemodynamics
- Arterial Bypass Grafting
Background:
- In situ vein arterial bypass is a common procedure for femoro-distal occlusive disease.
- The influence of patent graft branches, specifically arteriovenous fistulae, on surgical outcomes is not fully understood.
Purpose of the Study:
- To investigate the hemodynamic effects of patent graft branches during in situ vein femoro-distal arterial bypass.
- To determine the impact of preserving or ligating these branches on intra-operative graft flow and pressure.
Main Methods:
- Study involved 50 patients undergoing in situ vein femoro-distal arterial bypass.
- Branches were preserved as arteriovenous fistulae in 35 grafts; effects of occlusion release on graft flow were measured.
- Fistula types were classified based on their location and hemodynamic impact.
Main Results:
- Preserving branches as fistulae significantly increased proximal graft flow but reduced distal graft flow in many cases.
- Three distinct hemodynamic types of fistulae were identified, with calf perforator branches most frequently decreasing outflow.
- Distinguishing between these hemodynamically different branches during surgery was challenging.
Conclusions:
- Patent graft branches (fistulae) do not improve, and can potentially reduce, distal graft flow.
- Ligation of all arteriovenous fistulae during operation is recommended to optimize outcomes in femoro-distal arterial bypass surgery.
Abstract:
The effect of patent graft branches on intra-operative graft flow and pressure has been studied in 50 patients undergoing in situ vein femoro-distal arterial bypass. In 35 grafts in which patent branches in the calf and thigh were preserved as arteriovenous fistulae, release of temporary branch occlusion increased mean proximal graft flow by 178.6% in 32, and reduced distal graft flow by 49.7% in 30. Seventeen limbs had thigh fistulae only: release of temporary fistula occlusion produced a fall in distal graft flow in only three. We identified three types of fistula: (a) cutaneous branches usually found in the thigh, which do not affect graft flow; (b) perforator branches which increase graft inflow but have no effect on distal graft flow: (c) perforator branches which increase graft inflow and decrease graft outflow, and are most frequently found in the calf. Discrimination between these haemodynamically differing branches at operation proved difficult. Since patent branches never improve distal graft flow and may reduce it, we recommend that all fistulae are ligated at operation.