History:

Professor Colin Caro, Veryan Medical’s inventor founder and Research Director, is a recognised world authority in the field of fluid flow and vascular disease. He has worked in the field for over 35 years, has over 200 publications to his name, and is acknowledged to be the first to link the physics of blood flow with the occurrence of atherosclerosis, the disease of the arteries that causes among other major conditions heart attack and stroke. This research continues at Imperial College, London, under the guidance of Professor Caro, with researchers from six different departments and three teaching hospitals.

The research at Imperial College is now complemented by development projects underway in Scotland, the Netherlands, the USA, and Ireland.

Vascular Disease:

Approximately half of all deaths in industrialized societies can be attributed to vascular disease, mainly cardiovascular disease. It represents the largest unmet medical need in the modern world, and the world’s largest and fastest growing medical market.

The disease manifests itself by the progressive blockage of arteries, which restricts the flow of blood and nutrients to critical organs such as the heart, brain, kidneys, and limbs. Vascular disease preferentially develops in regions of stagnant flow, and often at arterial junctions where flow disturbance creates areas of high and low wall shear. Critically, the disease forms in areas of low wall shear, where there is insufficient supply of nutrients to and waste from the vessel wall.

The body’s natural defence against the propagation of vascular disease is to generate smooth swirling flow through the arteries, and particularly at arterial junctions. This is achieved by the gentle helical geometry of the arterial system. Natural swirling flow eliminates zones of high and low wall shear, cross-mixes nutrients to ensure optimum supply to the vessel wall, and sweeps areas of potential stagnant flow. Additionally, the correct level of stable flow against the artery wall activates important defensive genes, which further prevent disease proliferation. Nevertheless, despite this natural defence mechanism, other factors such as smoking, diet, and physical inactivity can lead to the development of the disease.

Treatments for Vascular Disease:

Advanced vascular disease cannot be reversed by drug therapy, and most patients rely upon surgical intervention. For coronary intervention, the use of stents has increasingly replaced bypass surgery. A stent comprises a cylindrical metallic framework, which is inserted into the restricted vessel via a catheter, and is expanded to enlarge the flow area at the site of the restriction, where it is left in place to effectively hold the vessel open to flow. Over 40% of coronary stents failed in the first year owing to the development of stent-associated vascular disease, a process called restenosis, which could occlude the narrow bore coronary artery within a small number of months. An effective solution to coronary artery stent restenosis was provided by the advent of drug eluting coronary stents, which were coated with a slow-release polymer containing drugs to prevent proliferation of disease cells. Drug eluting stents have reduced coronary stent restenosis to acceptable levels.

Drug eluting stents have not, however, proved so successful in important areas of peripheral vascular disease such as the neck (carotid artery stents), legs (femoral artery stents), and kidneys (renal artery stents). Much vascular disease associated with coronary stent restenosis is thought to focus on areas where the artery wall has been scarred by stent implantation. In larger peripheral arteries this type of vascular disease only provides one element of a more complex disease process, much of which is controlled by blood flow dynamics. Additionally, many peripheral vascular stents are subject to physical stresses that can lead to early mechanical failure.

The VeryanFlow^TM Solution:

Currently available vascular stents and grafts are two-dimensional tubular devices, which generate unstable, non-swirling blood flow into the downstream vessel. As a result, they speed the development of vascular disease in their outflow tracts, and possible for a considerable distance downstream of the device.

Veryan Medical is developing a platform of vascular technologies to more effectively address peripheral vascular disease by re-introducing natural swirling blood flow. This stable, swirling blood flow smoothes vessel wall shear at the outflow tract, provides effective cross-mixing to optimise nutrient supply to the vessel walls, and washes out potential areas of stagnant flow.

The SwirlGraft^TM has demonstrated that stable swirling blood flow at the outflow of a vascular graft demonstrably reduces vascular disease (outflow stenosis) and improves graft patency. Veryan Medical’s SwirlFlow^TM stent platform is initially being developed for femoral artery disease, where the helical stent geometry has two important advantages: improved mechanical flexibility and durability, and the generation of stable swirling flow to control this area of complex disease progression.

Veryan Medical’s technology platform is protected by ten granted and pending international patents dating from 1993.