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Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - SpiraStent (DEVELOPMENT OF A SPIRAL LAMINAR FLOW INDUCING ENDOVASCULAR STENT FOR THE TREATMENT OF PERIPHERAL ARTERIAL DISEASE)

Teaser

Summary

Overall project objective: to develop an innovative endovascular stent to reintroduce the natural spiral laminar flow both through the stent and distal to the stent, that can be manufactured to be deployed using standard delivery system profiles. To understand and overcome the technical requirement for incorporating the nitinol SLF inducer to a nitinol stent, Phase 1 had the following objectives:
1. Validation of the modifications to existing stents as a way forward
Commercially available stents were technically evaluated to assess the capability of modification with a spiral laminar flow inducer. The results demonstrated the ability to create Spiral Laminar Flow and showed that the stent design will need to be customised to meet the performance requirements. A full testing plan (in accordance with the relevant ISO) has been produced for Phase 2.
2. Assess stent covering to see how this will affect the stent
Covered and uncovered stents were modified to determine the effect of stent covering. Mechanical tests assessed whether the covering adversely effects the structure, pliability and expected function of the stent. This allowed us to determine that modification of pre-existing stents is a technically viable option.

3. Determine the nitinol stent patent landscape and additional IP regime
Intellectual property searches were conducted to determine whether patents exist that have claimed the use of nitinol to modify blood flow through medical devices. This indicated that we have freedom to operate in this area. The company has potential to file new Patents in Phase 2 development to strengthen the current 17 Patent families in the Patent estate. The company has a further approved Trademark SLF* which describes the design platform.

4. Identify partners for manufacture and commercialization
We identified and engaged sufficient numbers of relevant, interested parties to participate in the manufacturing and route to market process. These potential partners can provide commercial services, quotations and appropriate lead-times. Parties identified were categorised into the following groups: Metal Stent Manufacture, ePTFE Covering, Assembly/Delivery, System/Sterilisation, ISO Testing and Pre-Clinical Testing.

A business plan and commercialisation plan have also been developed for the implementation of the project.

Phase 1 has shown that the concept is technically and commercially viable and a Phase 2 application is now being developed.

Work performed

\"Task 1: Validation of incorporating SLF inducer into existing stents
This task details the testing activities undertaken on proof of concept Self-Expanding Nitinol Peripheral Stents incorporating a Spiral Flow Inducing Ridge.
The main purpose of the tests was to enable a decision as to whether the development of a stent incorporating spiral laminar flow can be achieved by modifying an existing stent or whether VFT should embark on a programme to design and manufacture a unique stent incorporating SLF.
I. Scope
This task was specific to the products listed in Table 1. Table 2 shows the tests carried out.
Table 1: Product References
Product Code: Optimed/Creamedix
Proof of Concept #1
Description: Spiral Laminar Flow Stent 8 x 70mm

Product Code: Optimed/Creamedix
Proof of Concept #2
Description: Spiral Laminar Flow Stent 8 x 110mm Stent Design: Planis Modified rev.29

Table 2: Associated Document References (available on request)
T014-R Partially covered spiral stent first (acute) animal study
T015-R Partially covered spiral stent pre-clinical Thiel cadaver study
T016-R Partially covered spiral stent flow testing
T017-R Spiral stent coating and flow testing
T021-P Spiral Laminar Flow Stent Development Test Plan

Test Articles
Product Code: Optimed/Creamedix
Proof of Concept #1
Description: Spiral Laminar Flow Stent 8 x 70mm
Stent design based on Optimed Sinus Stent

Product Code: Optimed/Creamedix
Proof of Concept #2
Description: Spiral Laminar Flow Stent 8 x 110mm Stent Design: Planis Modified rev.29
Lot : EW- 2014-205 #1 to EWâ€“ 2014 -205 #4
Stent design based on Optimed Sinus Flex Stent

II. Test Summary and Discussion

T017 Spiral stent coating and flow testing (Proof of concept design #1)
The prototype spiral stent (based on an Optimed Stent with closed cell diamond pattern) was successfully modified (using a heat/mechanical deformation process) to incorporate the P3 Ridge Profile as used on the current range of commercially available ePTFE Vascular Grafts. The stent supplied was uncovered and was successfully coated with latex rubber to create the spiral laminar flow fin (an uncovered stent of this design will only create turbulence). A single spiral flow was found in the outflow of the device using colour Doppler and vector Doppler ultrasound imaging. The non uniform nature of this single spiral has been associated with the abrupt termination of the spiral ridge at the end of the stent. This issue will be factored into Proof of Concept design #2.
In addition to verification of Spiral Laminar Flow this testing supports:
T021-P Spiral Laminar Flow Stent Development Test Plan
â€¢ Test 1: Visual Inspection and dimensional verification

T016 Partially covered spiral stent flow testing (Proof of concept design #2)
The prototype spiral stent (based on an Optimed Sinus Flex Stent with open cell ring and strut pattern) was successfully modified (using a heat/mechanical deformation process) to incorporate the P3 Ridge Profile as used on the current range of commercially available ePTFE Vascular Grafts. In addition to the change of basic stent design, the inducer ridge was modified at either end to replicate the run in/run out as feature on the graft design. This stent has been further modified to include an ePTFE covering along the length of the flow inducer ridge. This covering process requires further investigation/optimisation/development.
The flow was tested in both ends of the spiral stent after reversion of the flow direction. One strut in one end of the spiral stent was broken.
The non-broken strut end was able to create a uniform and steady single spiral flow. A steady single spiral started to be observed at 3.5 cm after the stent inlet and was completely formed 6.5 cm distal from the stent inlet. This information will be used in future design efforts to decrease the length of the spiral ridge and consequently the overall length of the device.
The flow disturbance at the top side of the colour Doppler images from th\"

Final results

Peripheral arterial disease (PAD) is one of the fastest-growing and most pervasive diseases, and it is estimated to affect 27m individuals in Europe and North America of which 10.5m are symptomatic and 16.5m asymptomatic. Symptomatic PAD or intermittent caudation (IC) is usually diagnosed by a history of muscular leg pain when exercising and is relieved after a short period of resting. Vascular Flow Technologies has demonstrated with its two graft products that re-introducing spiral blood flow increases the patency of the product in the short and medium term. The SpiraStent project will develop a self-expanding stent that will reintroduce the bloods normal spiral laminar flow both through the stent and downstream to the stent, which will in turn reduces the laterally directed forces and turbulence and therefore lower the rates of distal disease progression.

The SpiraStent project will allow VFT to build on their SLF platform with an innovative stent design that improves outcomes for patients, reduces healthcare costs and will help grow the technical jobs market in the EU