The initial clinical evaluation of this product began in 2001 with the McMaster Thrombosis group, including Drs. Martin O'Donnell, Jack Hirsh, Jeff Ginsberg and Dr. Susan Kahn of McGill University, by examining a population of patients suffering from severe post thrombotic syndrome. 

Results of these early trials demonstrated up to a 64% increase in venous blood circulation in calf veins and an 88% improvement in blood flow in veins of the thigh¹ after 50 minutes of device use. A phase II patient series² and subsequent randomized control trial involving patients who presented with chronic venous insufficiency caused by the PTS, showed improvement in symptoms without any serious side effects, and patient preference for the VW5. The most severely affected patients were able to remain mobile and improve their quality of life using the VW5². This has significant clinical impact considering the difficulty and reduced quality of life these patients face.

1. O'Donnell M, Ginsberg J, Kearon C, et al. Effects of a novel venous return assist device (Venowave) on lowe limb venous flow in patients with post-thrombotic syndrome, Blood 2002: 100 (11 Suppl): 3950.
2. O'donnell M, Ginsberg J, Saringer J, et al. Evaluation of a venous-return assist device (Venowave) to treat post-thrombotic syndrome: a phase II study. Thromb Heamost 2008 Supplement 1; July abstract P:1374
3. O'Donnell M, McRae S, Kahn S, et al. Evaluation of a venous-return assist device to treat severe post-thrombotic syndrome (VENOPTS): A randomized controlled trial. Thromb Heamost 2008:99: 623-629

Based on the results of pressure tests with the Venowave running under a variety of conditions and with patient undergoing a normal range of physiological movements the following can be concluded:

1. The Venowave pumps effectively under a full range of strap tensions from very loose to very tight. There is however, increased static pressure in the leg when the straps are tight and the unit is turned off. It is therefore prudent to apply the Venowave with light to moderate strap tension at all times and avoid high strap tension.
2. The Venowave active pressure rises and falls synchronously with changes in a patient’s leg orientation, applying more pressure when it is needed in a standing position and less with the foot elevated. This indicates that there is no need to adjust the Venowave to accommodate a normal range of physical activities or orientations of the leg.
3. The Venowave is capable of consistently delivering pressure from a low of 0mmHg to a high of 130mmHg automatically adjusting to different situations when required. The range of pressures delivered by the Venowave coincides with the pressure ranges typically delivered with pneumatic driven devices.
4. The Venowave applies its most effective pumping action where the wave surface meets the body. Further removed from the device, pressures and pressure variations diminish rapidly as the distance from the acting wave surface increases. The Venowave is therefore most effective in pumping the area of the calf directly where it is applied.
5. The Venowave increases blood flow and reduces venous pressure within a single cycle of operation, or within seconds of being turned on.
6. The pumping performance of Venowave is very robust and independent of patient activities or settings of the device.
7. To avoid hypertension or increased pressure in the lower leg, high strap pressure when the unit is turned off should be avoided.

These tests results and interpretation were carried out with the assistance of Dr Hugo Partsch. Venowave was inspired by Dr Jack Hirsh’s identification of the clinical need for this device as well as years of support directly and indirectly from McMaster University and the Hamilton teaching hospitals and the numerous staff who provided insight and guidance into the clinical applications and needs of the product.