Øyvind in the lab, testing the negative pressure boot.
Peripheral arterial disease is a growing epidemic that currently affects more than 200 million people worldwide and more than 40 million people in Europe alone. In comparison, approximately 34 million people globally are living with HIV. Additionally, peripheral arterial disease is associated with a higher case fatality rate than HIV, due to cardiovascular ischemic events. Between 2000 and 2010, there was an approximately 24 percent increase in the occurrence of atherosclerotic cardiovascular disease. A study in Diabetes Care from 2012 reveals that annually, an estimated 150 000 patients undergo amputations related to peripheral arterial disease. Also, a substantial proportion of deaths worldwide are due to peripheral arterial disease. Hence, this is a significant and growing public health problem. Tackling this global cardiovascular disease epidemic requires not only a combination of sound knowledge of individual and societal preventive strategies, but also of appropriate medical and therapeutic interventions for dealing with high-risk and diseased individuals.
Peripheral arterial disease attacks the blood vessels in the lower extremities, restricts blood flow and may lead to amputation.
One of the first signs of peripheral arterial disease is reduced vascular function. This is often followed by reduced blood flow in the oxygen-rich blood vessels—the arteries—that distribute blood to every cell of the body. Atherosclerosis often develops in the lower extremities (peripheral, meaning not within the heart or brain), and later affects the arteries in the brain and heart—hence, the name atherosclerotic peripheral arterial disease. Peripheral arterial disease is caused by narrowing or occlusion of the blood vessels, due to fat and scar tissue buildup. This buildup forms a substance called plaque within the artery, which can substantially decrease blood flow.
The clogged arteries restrict blood flow—and hence, oxygen and nutrients—to the leg muscles. This can lead to unbearable pain, cramping, and a burning sensation in the calves, thighs, or buttocks that appears during exercise and is relieved by rest. This condition makes walking and exercise difficult and results in a profound limitation in functional capacity and quality of life. Moreover, depending on the severity of the disease, the development of chronic ulcers which may result in cell death (gangrene) can occur. In the worst case, amputation is the final and only treatment option.
Atherosclerosis. (Illustrasjon: NHLBI via Wikimedia Commons) (Illustration: NHLBI via Wikimedia Commons)
Treatment options of peripheral arterial disease are scarce.
Research has demonstrated promising results for treating heart blockages. However, for peripheral arterial disease, treatment options are scarce. Aside from supervised exercise, there have been few major pharmacological or noninvasive breakthroughs in the treatment of peripheral arterial disease that have been demonstrated to enhance and restore blood flow to the ischemic limb. Minimally invasive surgery, where the surgeon accesses the diseased artery via a larger blood vessel using a catheter (endovascular treatment), and surgery of lesions above the level of the groin, both show promising long-term results. The results to date of intervention below the groin level have proven less promising. Additionally, a large proportion of patients with peripheral arterial disease cannot undergo surgery due to other diseases, such as cerebrovascular and coronary heart disease, which contraindicate surgical intervention. Thus, despite numerous advances in interventional radiology and vascular surgery, there is an urgent need for new, less invasive treatments.
How can non-surgical options restore blood flow and take away the pain in patients with vascular disease?
Otivio AS has developed a non-invasive method for increasing blood flow to an extremity. This method is based on application of a pulsating negative pressure directly on a limited part of an affected limb. The pressure oscillates between negative pressure and atmospheric pressure, increasing blood flow because of the suction effect of the negative pressure on the limb. The device is intended to be used while sitting in a chair at home or in a hospital.
This doctoral project will look at the effect of applying the device on healthy subjects and patients with peripheral arterial disease using different pressures and settings to find out the best method to enhance blood flow to the extremity. A pilot study Otivio AS conducted during the summer of 2014 showed promising results. Patients experienced an acute increase of about 40 percent in blood flow in the peripheral arteries of the foot. The Ph.D. candidate, Øyvind H. Sundby, will test this method more broadly in 2015. In his research, Sundby will collect data on blood flow in the foot while applying negative pressure. The research will be conducted on both healthy subjects and patients with peripheral arterial disease in order to examine the effectiveness of the device. In addition, the research will attempt to find the most optimal pressure cycles to stimulate enhanced blood flow to the extremities. By increasing blood flow, patients may experience reduced pain and avoid wounds, infections, gangrene, amputation and complications related to surgery. Thus, the device may have a long-term impact on patient health.