Vascular Flow Technologies Spiral Flow™ AV Graft Improvement in Patency

Released: Thursday 16th April 2015




Spiral Flow™ AV graft shows substantial improvement in patency over current standard of care


Independent study shows primary patency of 72% at 18 months, compared to 36.7% for PTFE graft


Dundee, UK, 16 April, 2014 – Vascular Flow Technologies (VFT), the medical device company using proprietary Spiral Laminar Flow™ (SLF™) technology to replicate natural blood flow for enhanced patient outcomes, announce today the presentation of independent study results demonstrating substantially better primary patency rates for its Spiral Flow™ arteriovenous (AV) graft than for polytetrafluoroethylene (PTFE) graft.

The SLF graft for haemodialysis: midterm results of the first European series, was presented at the Vascular Access Society meeting in Barcelona, Spain, and showed 18-month primary patency rates of 72% for Spiral Flow™ AV graft, compared to 36.7% for PTFE grafts, which are the current standard of care. 

Investigator Dr Wolfgang Hofmann, of the Department of Vascular Surgery, Feldkirch General Hospital, Austria, who presented his data and analysis commented:  “The results are more than satisfactory, particularly as the patients receiving Spiral Flow™ grafts were negatively selected.”

The study compared primary patency rates for 15 patients receiving Spiral Flow™ AV grafts with a consecutive series of 87 patients receiving PTFE grafts.   Spiral Flow™ AV grafts were only used if, according to pre-operative duplex mapping, patients were not suitable for any type of autologous fistula.

Follow-up consisted of duplex mapping every 3 months, and additional duplex scanning if there was suspicion of impending shunt failure.   Of the 15 patients receiving Spiral Flow™ AV grafts, there were four shunt occlusions, of which two were managed by thrombectomy.  Primary patency at 18 months for Spiral Flow™ AV grafts, calculated by Kaplan Meier, was 72%, secondary patency was 85.5%. 

The study results provide strong support for the premise of VFT’s Spiral Flow™ technology.   Spiral Flow™ grafts are designed to encourage a spiral laminar flow within the graft, which replicates the natural flow in blood vessels.  This reduces turbulence at the distal (venous) end of the graft, so reducing shear stress, endothelial activation and platelet activation that precede thrombus formation at the distal anastomosis.  The study used duplex mapping to confirm the presence of spiral flow in the grafts. 

Dr Hofmann commented:  “We have long known that prosthetic graft failure is a normal tissue response to an abnormal flow environment.  It was particularly gratifying to see that changing the flow pattern at the venous anastomosis improves the patency of the graft.”


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