There are at least two mechanisms by which ArtAssist® improves blood flow. First, the foot, ankle and calf veins are almost completely emptied in the sitting position by using pressures that are over twice those typically used in deep venous thrombosis and lymphedema compression devices. By compressing all the tissues below the knee, a large volume of venous blood is emptied with venous pressure dropping to nearly zero. The increased arterial-venous pressure gradient results in greater arterial flow (Flow=Pressure Gradient/Resistance).

Increases Patients' Blood Flow in the Popliteal Artery

Increases Skin Perfusion at the Foot

Superficial Femoral Artery Occulsions

Intermittent Claudication

Super Femoral Artery Occulsions

The increased pressure gradient alone does not account for the large blood flow increases seen with ArtAssist®. A second mechanism for action involves the endothelium, the cellular lining of all vessels. This structure is recently seen as playing an important role in controlling peripheral resistance. Endothelial cells are known to release substances, including nitric oxide (NO) and tissue factor pathway inhibitor (TFPI), which act as vasodilators and anticoagulants. These substances are released in amounts corresponding to the shear rate of blood along the vessel's endothelial surface. The very rapid increase and decrease of ArtAssist's compression creates high shear rates intended to stimulate endothelial release of these and other important biochemical factors and possibly stimulates collateral formation. Higher blood shear rates and associated pulsatile flows prevent and reduce platelet and macrophage adhesion to endothelial surfaces which otherwise cause an inflammatory reaction which furthers endothelial dysfunction. The endothelial layer then becomes a barrier to the transport of metabolic products to and from the surrounding tissues, creating a so-called "microvascular steal." Tissue plasminogen activator (tPA), a powerful endogenous thrombolytic agent, is produced by the endothelium but in greatly reduced amounts when pulsatile flow ceases. It is well known that arteriopaths loose precapillary vasomotor control - pulsatile flow is thought to restore it. Also, proper vascular distribution within tissues is known to be based upon flow rates and associated shear stress (pulsatility). Over long periods of time (several months), it is thought that the shear stress induced by ArtAssist® may cause proper redistribution or "remodeling" of the microvascular network. This is why ulcers are healed with ArtAssist® but it remains essential that the patient maintain high, pulsatile flows to the affected tissues by regular exercise after ArtAssist® treatment is stopped.

Doppler Imaging ArtAssist® increases popliteal artery blood flow by 3.1 times using duplex ultrasonic imaging. The images below show pre-compression and post-compression velocities on a patient with Fem-pop disease.

INCREASED BLOOD FLOW BY 3.1 TIMES

ArtAssist®, VenAssist®, VenaPulse®, and APG® are register trademarks of ACI Medical, Inc., San Marcos, CA, USA.