Approximately two million Americans are living with a limb amputation–that's about one in every 200 people In the United States (US).^1,2 The majority (54%) of the 185,000 amputations in the US each year are due to vascular disease, with trauma- and cancer-related amputations accounting for 45% and <2%, respectively.^3,4 While trauma- and cancer-related amputations have declined by about half in recent decades, it is concerning that limb amputations caused by poor vascular status (i.e., ischemia) have increased.⁵ Even more alarming are projections that, given current trends, by the year 2050 the number of people living with an amputation will roughly double to 3.6 million.⁶

Amputations due to vascular problems most often occur secondary to peripheral vascular disease and diabetes–thus, many are preventable. Projections indicate that reducing the incidence of amputation due to vascular disease by 10% would dramatically reduce (by approximately 225,000) the number of Americans living with an amputation.⁷ This is the mission of the Limb Rescue Clinic at the Medical University of South Carolina (MUSC).

Two years ago, the Limb Rescue Clinic opened its doors as a multi-disciplinary center of care dedicated to preventing and treating critical limb ischemia (CLI) and improving patients' quality of life. A serious form of peripheral arterial disease, CLI is a chronic condition in which atherosclerotic plaques block arteries in the lower limbs. Poor blood flow then causes sores or ulcers to develop and prevents wounds in the legs and feet from healing. Patients may eventually experience significant pain in their feet at rest, which signals severe ischemia and is associated with amputation rates as high as 50% within one year if left untreated. Critical limb ischemia requires expeditious treatment to re-establish blood-flow in the affected area.

"Our purpose is to provide comprehensive care to these complicated patients who often have multiple comorbid diseases that put them at high risk for developing CLI," says Thomas Todoran, MD, Associate Professor of Medicine and Director of Vascular Medicine in the Division of Cardiology at MUSC. "Peripheral artery disease (PAD) is very common. It's caused by risk factors such as diabetes, high blood pressure, smoking, and high cholesterol. If you look at cardiovascular disease in general, it's really a systemic illness of the vasculature that affects most small and larger arteries of the body. CLI is the end stage of vascular disease," explains Todoran.

Because the Limb Rescue Clinic uses an interdisciplinary team-based model, each patient receives a plan of care that is tailored to their unique needs and where they are on the disease spectrum. Dedicated cardiovascular prevention professionals focus on addressing lifestyle risk factors including smoking cessation, cholesterol control, and diabetes management. Endovascular and vascular surgeons determine the best technique for restoring blood flow to the affected area. Wound care nurses and post-operative counselors help surgical patients get through their recovery and back to their lives. "With all that's usually going on with these patients, we really have to take a multi-disciplinary approach if we're going to get the best outcomes for them," says Todoran.

Not only does the Limb Rescue Clinic provide a full complement of traditional services in one place, it also offers cutting-edge technology and surgical procedures that expand patients' treatment options–which can be critical for those who have been told an amputation is unavoidable. Thomas Brothers, MD, Professor of Surgery in the Division of Vascular Surgery explains, "We have a number of technologies that may not be available at smaller hospitals–from hybrid operating rooms to advanced catheterization and interventional radiology rooms. We have a wide range of catheters, balloons, stents (including drug eluting stents), and atherectomy devices in addition to the option of open surgical therapy when endovascular techniques are not possible. Plus, we're involved in a number of clinical trials. I'm really excited about a new stem cell therapy trial we're able to offer to grow new blood vessels in patients who do not have the option of opening or bypassing existing, blocked vessels."

Despite all the advanced technology available, early diagnosis and referral remain the biggest obstacles to reducing amputation rates in South Carolina. Patients with PAD often have a complex medical history with multiple comorbid conditions that make it easy to miss a small foot ulcer or new leg pain. In addition, some patients may think discomfort in their legs or changes in skin texture are to be expected given their health problems. "I think it's reasonable to get a consult when someone does not have normal foot pulses on palpation, especially if they have a wound on their foot–certainly if that wound isn't healing or if they have pain in their legs. Physicians should be feeling for pedal pulses, and if they have any suspicion that there may not be adequate circulation, we'll be more than willing take a look," says Brothers. "It's always a matter of recognizing the problem. At the end stages, most people recognize there's a problem, but we need to get involved earlier in the process to help them avoid an amputation. If we get involved sooner, we may well be able to help them get a different outcome."

Ironically, the rapid pace of technological advancement has contributed to these challenges by creating a knowledge gap about what is possible. Many current interventions to prevent PAD, slow disease progression, and restore blood flow were not available a decade or two ago. "We're treating the risk factors and the vascular disease as a systemic illness that affects all of the vascular beds. In terms of medical therapies, we have many more statin options now that we didn't have 10 to 15 years ago. We've also taken a big leap forward with endovascular therapies–balloons and stents coated with agents that reduce re-narrowing of vessels and new techniques to open vessels," says Todoran.

The Limb Rescue Clinic continues to add new capabilities that will improve outcomes for patients with vascular disease. Later this year, a new surgical robot will join the team. In addition, the Limb Rescue Clinic is actively expanding its telehealth initiative to make long term follow-up easier for patients and to provide more convenient physician consultation.

 

--Kat Hendrix

 

Resources

1. Ziegler-Graham K, et al. Estimating the Prevalence of Limb Loss in the United States - 2005 to 2050. Archives of Physical Medicine and Rehabilitation. 2008. 89:422-429.
2. Adams PF, et al. Current Estimates from the National Health Interview Survey, 1996. Vital and Health Statistics 1999. 10:200.
3. Owings M, et al. Ambulatory and Inpatient Procedures in the United States, 1996. Hyattsville, Md.: US Dept. of Health and Human Services, Centers for Disease Control and Prevention, National Center for Health Statistics; 1998.
4. Ziegler-Graham K, et al. Estimating the prevalence of limb loss in the United States: 2005 to 2050. Arch Phys Med Rehabil. 2008; 89: 422-429.
5. Amputee Coalition. National Limb Loss Resource Center. Limb Loss Statistics. Available at: https://www.amputee-coalition.org/resources/limb-loss-statistics/
6. Ziegler-Graham K, et al. Estimating the prevalence of limb loss in the United States: 2005 to 2050. Arch Phys Med Rehabil. 2008; 89: 422-429.
7. Ziegler-Graham K, et al. Estimating the prevalence of limb loss in the United States: 2005 to 2050. Arch Phys Med Rehabil. 2008; 89: 422-429.