Technology overview

This briefing describes the regulated use of the technology for the indication specified, in the setting described, and with any other specific equipment referred to. It is the responsibility of healthcare professionals to check the regulatory status of any intended use of the technology in other indications and settings.

About the technology

CE marking

Vascular Flow Technologies was awarded a Class IIb CE mark for the Spiral Flow peripheral vascular graft in August 2007. The CE mark covers the different sized grafts from 50–80‑cm lengths and 6 and 8‑mm diameters.


The Spiral Flow peripheral vascular (PV) graft is made from expanded polytetrafluoroethylene (ePTFE), for treating peripheral arterial disease. In the distal portion of the graft there is a 'spiral flow inducer' in the form of a ridge that creates a helix on the lumen of the graft. This helix causes blood passing through the graft to move in a spiral flow. The manufacturer claims that this spiral flow ensures natural blood‑flow patterns and normal pressure in the artery to reduce the risk of neointimal hyperplasia (NIH). The graft is available in 50, 60, 70 and 80‑cm lengths, and in diameters of 6 or 8 mm.

The Spiral Flow PV graft contains a distal cuff that is separated from the spiral flow inducer segment by a 3–5‑mm area called the 'trim gap'. The distal end of the graft can be cut up to the trim gap to modify the graft's toe in preparation for suturing to the heel of the target vessel. This trim gap ensures that the spiral flow inducer segment is not inadvertently cut, thereby disrupting the graft's ability to generate spiral flow. However, the manufacturer recommends that a portion of the trim gap be left in place to allow for clamping of the graft to achieve haemostatic control. The graft can also be reduced in length by cutting its proximal (nearest) end.

The manufacturer recommends that the distal end of the graft should be connected to the artery first. The heel of the artery should be aligned to the end of the spiral inducer segment to provide the correct geometry for spiral laminar flow. To hold the graft in place, a tunnel must be made through the tissue surrounding the damaged vessel. The graft is fed through this tunnel before the proximal end of the graft is connected to the artery, bypassing the damaged section.

Intended use

The Spiral Flow PV graft is intended for use in patients with symptomatic peripheral arterial disease (PAD) in whom a peripheral vascular bypass procedure using a prosthetic graft is clinically indicated. The Spiral Flow PV graft is also indicated for use in intravascular access for haemodialysis. This indication is beyond the scope of this briefing.

Setting and intended user

The device is designed to be used in the secondary‑care inpatient setting. It is intended only to be used by suitably qualified clinicians who are experienced in carrying out peripheral vascular bypass procedures.

Current NHS options

Currently there is no cure for peripheral arterial disease (PAD) and initial management places a focus on lifestyle changes to reduce symptoms. These changes include:

  • exercising

  • giving up smoking

  • eating a healthy diet

  • cutting down on alcohol.

Medications such as statins, antihypertensives and antiplatelets can also be prescribed to treat the underlying cause of PAD and help reduce the risk of developing other types of cardiovascular disease (NHS Choices). Additionally, NICE technology appraisal guidance on cilostazol, naftidrofuryl oxalate, pentoxifylline and inositol nicotinate for the treatment of intermittent claudication in people with peripheral arterial disease has previously recommended naftidrofuryl oxalate for treating intermittent claudication in people with PAD.

Surgical procedures, including angioplasty and bypass grafts, are additional treatment options for PAD. These aim to restore the flow of blood through the arteries of the legs, known as revascularisation. Angioplasty is a method where the narrowed area of the artery is widened by a small balloon, which is inflated inside the vessel. Sometimes a 'stent' or small mesh tube may be left in place to keep the artery open.

Bypass surgery may be offered to people with severe lifestyle‑limiting intermittent claudication when angioplasty has been unsuccessful or is unsuitable, and where imaging has confirmed that it is appropriate. It may also be used in people with critical limb ischaemia needing revascularisation. NICE's guideline on lower limb peripheral arterial disease recommends that an autologous vein should be used whenever possible. A range of synthetic grafts is currently available to the NHS and current practice varies in the choice of graft.

NICE has also issued guidance on percutaneous laser atherectomy as an adjunct to balloon angioplasty (with or without stenting) for peripheral arterial disease.

NICE is aware of the following CE marked devices that appear to fulfil a similar function to the Spiral Flow PV graft:

  • Gore Propaten heparin‑bonded vascular graft

  • Gore INTERING vascular graft.

Costs and use of the technology

The list prices of the different sized (diameter by length respectively) Spiral Flow PV grafts, excluding VAT, are:

  • Spiral Flow PV graft 6 mm×50 cm: £952

  • Spiral Flow PV graft 6 mm×60 cm: £1032

  • Spiral Flow PV graft 6 mm×70 cm: £1320

  • Spiral Flow PV graft 6 mm×80 cm: £1520

  • Spiral Flow PV graft 8 mm×50 cm: £952

  • Spiral Flow PV graft 8 mm×60 cm: £1032

  • Spiral Flow PV graft 8 mm×70 cm: £1320

  • Spiral Flow PV graft 8 mm×80 cm: £1520.

The lifespan of the technology is dependent on functionality of the graft. Grafts with higher patency rates are less likely to need repeated interventional procedures and will therefore reduce overall cost to the NHS.

In 2013–14, 4285 bypass procedures of the femoral artery were performed, including 330 emergency procedures. Of these 2542 used autologous vein grafts, while 810 used prosthetic grafts (HSCIC 2015).

The payment by results tariff for 2013–14 (Department of Health 2013) has been provided for information. The NHS tariffs for outpatient attendance relating to consultant‑led vascular surgery services (service code 107) are:

  • first attendance: £156 (WF01B/WF02B)

  • follow‑up attendance: £93 (WF01A/WF02A).

The NHS costs for combined day case or ordinary elective spells (Payment by Results 2013–14) are:

  • bypasses to tibial arteries: £8266 (HRG code, QZ03Z)

  • amputations without complications and co‑morbidities: £7625 (HRG code, QZ11B)

  • amputations with complications and co‑morbidities: £14,724 (HRG code, QZ11A).

The costing report for the NICE guideline on lower limb peripheral arterial disease suggests that amputation may be offered when revascularisation options such as bypass cannot control critical limb ischaemia. It estimates that in addition to the procedure itself, the cost of care to the NHS is approximately £20,000 per patient in the year following an amputation.

Likely place in therapy

The Spiral Flow PV graft could be used for patients with peripheral arterial disease needing a synthetic bypass graft. Use of the device is not expected to change the current clinical pathway.

Specialist commentator comments

Two specialist commentators stated that the Spiral Flow peripheral vascular (PV) graft is more expensive than standard expanded polytetrafluoroethylene grafts and there is not enough evidence to make a conclusion about whether it is better. One commentator noted that randomised controlled trials and cost-effectiveness analyses would be needed in order to make a confident conclusion about the effectiveness of the Spiral Flow PV graft. Another commented that although the available studies use patency as an outcome measure, studies that measured amputation rates or wound healing would be more clinically relevant.

Two specialist commentators noted that the quality of evidence for the Spiral Flow PV graft is very limited, and suggested that the results should be treated with caution.

One specialist commentator noted that while the evidence for this device is limited, with some evidence prone to methodological problems and bias, this is an interesting concept that is backed by basic science.

Equality considerations

NICE is committed to promoting equality and eliminating unlawful discrimination. We aim to comply fully with all legal obligations to:

  • promote race and disability equality and equality of opportunity between men and women, and

  • eliminate unlawful discrimination on grounds of race, disability, age, sex, gender reassignment, pregnancy and maternity (including women post‑delivery), sexual orientation, and religion or belief (these are protected characteristics under the Equality Act 2010).

Peripheral arterial disease (PAD) is more common in people over the age of 60 years and affects more men than women. People with diabetes have an increased risk of developing PAD, and diabetes is recognised as a long‑term health condition that may cause disability. Age, sex and disability are protected characteristics under the Equality Act 2010.