7. Vascular Flow Technology: Another run of the mill graft or a breakthrough technology?
Experience and perspective from a European centre.
Presented at the 35th Charing Cross International Symposium, 7th April, 2013, London, UK
Prim. Univ.-Doz. Dr. Wolfgang J. Hofmann
Department of Vascular Surgery, Landeskrankenhaus (LKH) Feldkirch, Austria
The AV access strategy at LKH Feldkirch focusses primarily on utilising native fistula and Duplex mapping of the upper extremity is undertaken to identify the most appropriate of the following approaches:
- Cimino Brescia Fistula
- Cubital Fistula
- Ulnar Artery – Basilic Vein Shunt
- Transposition and Shunting of the Basilic Vein
AV prosthetic grafts are only used in patients if using a native fistula is not possible. So these are negatively selected. Conventional AV grafts typically require one to two revisions per year.
There is neointimal hyperplasia at the heel, toe and bed of the anastomosis. This is due to turbulence at the venous anastomosis.
In order to prevent stenosis and occlusion a number of tactics were tired unsuccessfully in the last 10 years, including:
- Configuration of the Anastomosis (Venaflo®)
- External beam radiation
- PTA (repetitive)
On introduction to the Spiral Flow graft in 2010, a Duplex scan confirmed that this spiral movement in a normal healthy artery is real and if you can see it. The first Spiral Flow graft implantation was undertaken in September 2010.
More than 26 months after implantation, that graft is working well and we have spiral flow at the venous anastomosis.
Since September 2010, a series of 10 cases have been completed so far. All patients have had previous surgery (mean of 3.8 previous procedures; median of 3) Only three patients were diabetic, which is less than our average. Mostly loop grafts in the forearm are utilised.
Only one problem was observed. One patient had an early occlusion of graft only two months after implantation. A revision was undertaken thinking that the venous anastomosis could be slightly better in a more proximal position. Another spiral graft was implanted but it thrombosed also. As it was discovered that this patient is an alcoholic, who is said to sleep with his head on his arm (directly over the graft), it was decided to abandon further graft therapy (the patient is now on a dialysis cannula).
Currently, 10 grafts have been implanted in nine patients with a mean follow-up of six months.
Only two failures were observed, both in the same patient. All other grafts are patent and on haemodialysis with no evidence of neointimal hyperplasia (NIH) under Duplex review.
- 10 grafts in nine patients
- Mean follow up 6.1 months (range: 31 – 1 months)
- Two early failures in one patient (patient deemed not suitable for treatment)
- All other grafts patent (80%) without evidence of NIH in Duplex control
From our European perspective, this Spiral Flow Graft, which restores the natural blood flow pattern, seems to be a strong tool to prevent stenosis at the AV graft venous anastomosis.