Eight million Americans suffer from lower extremity peripheral arterial disease (PAD) and many suffer ischemic leg pain so severe that walking more than a few minutes becomes impossible. Over 500,000 adults experience progressive pain, debilitating immobility, limb amputation, and premature death. Vascular surgery, pharmaceutical intervention, and dose-dependent exercise provide only temporary benefits. Research shows functional electrical stimulation (FES) can improve blood flow for people with PAD and ischemic pain. Building on earlier research, our laboratory has developed an innovative ambulatory FES system which provides precise stimulation to replicate normal walking muscle contractions and can adjust to changes in walking velocity and cadence. Previous studies show this system is more comfortable than other systems, convenient for home use, can reduce walking pain, and improve walking skills. Preliminary investigations in our lab show when participants use this device for 8 weeks and walk an hour each day, ischemic pain is gone even after a full hour of walking. When compared to the increasing costs of vascular surgery and limb threat treatment, this FES system may provide a superior outcome for patients with intermittent claudication, and at a fraction of the cost. We hypothesize that applying this FES system and walking one hour/day (FES+Walk) for 8 weeks of intervention will significantly reduce claudication, improve locomotion, and enhance quality of life when compared to walking one hour/day (Walk) without stimulation. A randomized block design will assess outcomes before, after, and 8 weeks after intervention in a group of 20 adults with PAD and intermittent claudication who receive FES+Walk compared to a comparable group of 20 adults who only Walk. This hypothesis will be addressed in these Specific Aims: to determine if 8 weeks of home administered FES will (1) decrease ischemic pain, (2) improve walking endurance and velocity, and (3) enhance quality of life when comparing FES+Walk vs. Walk. If this exploratory study shows that daily FES can provide pain free walking for adults with PAD and intermittent claudication, future studies could investigate if this system will decrease the incidents of lower limb amputations and reduce mortality. Eventually, this approach may generalize to patients with COPD, CHF, and PVS to encourage exercise, improve cardiovascular health, and reduce secondary complication in these populations.
This study will take the first step to improve public health for millions of Americans with Peripheral Arterial Disease who cannot walk due to leg pain. We will assess a proof of concept, home administered, electrical stimulation system to resolve pain, improve walking, and enhance quality of life. Future studies could then assess if this system will prevent amputation and premature death.