Direct revascularization through targeted angiosomes is proving to be successful in the treatment of critical limb ischemia (CLI) and peripheral artery disease (PAD), particularly in wound healing for patients suffering from diabetes and end-stage kidney disease. Studies show that revascularization through a source artery to the angiosome often results in better wound healing and limb salvage rates, according to Christopher Huff, MD, of Cardiovascular Associates in Birmingham.
The angiosome concept defines the human body in three-dimensional areas of tissue that are fed by arteries and vessels. These areas are angiosomes. “As technology has evolved, our understanding of PAD and CLI has evolved, and more research has been directed toward how we can successfully heal wounds and thus prevent amputation,” Huff says. “The angiosome concept makes a lot of sense if you think about it from a coronary artery standpoint. If a patient’s stress test shows ischemia in the LAD territory, we don’t solve the problem by fixing the right coronary artery. Similarly, there are three arteries below the knee that run to the foot. Those three arteries are responsible for different areas of tissue to the foot, and if you lose one of those arteries, the other arteries have to take over and make up for the lost blood flow.”
Huff points out that diabetics and patients with end-stage kidney disease don’t compensate well when an artery is blocked and can’t form the natural bypasses required for adequate limb perfusion. That is especially problematic if they have a foot wound. “There may be enough blood flow to prevent tissue loss from ischemia, but there is not enough blood flow for healing should the patient develop a wound from an external injury,” he says.
For example, if a patient has a wound on the bottom of the foot and there is blockage in both the anterior and posterior tibial arteries, it is the posterior tibial artery that needs to be fixed, since it is the artery that supplies blood flow to the bottom of the foot, Huff says. “It seems simple enough, but not everyone approaches CLI in this manner, which may be why some patients don’t have successful wound healing after revascularization. To maximize wound healing, you need direct blood flow from the aorta all the way to the wound. Using our knowledge of angiosomes, we revascularize the artery that supplies blood to that area and the wound heals.”
Though the angiosome concept for revascularization is relatively new, Huff is confident that its application can reduce amputations. However, he says that physicians need to know who is at risk for CLI and be aggressive about referring patients with wounds to a CLI specialist, even if the referring doctor feels the patient has adequate blood flow.
“If the patient has no claudication and the doctor feels a pulse on the top of the foot, they assume there is good blood flow so they don’t see the need to refer them to a specialist. The problem is that 40 percent of PAD patients don’t have claudication (1), and a palpable pulse on the top of the foot doesn’t mean there is adequate blood flow to all areas of the foot,” Huff says. “Without referral, they will not get appropriate testing and subsequently won’t get an intervention to correct the problem.”
According to Huff, data shows that 90 percent of amputations can be prevented with intervention (2), but only 50 percent of these patients have an angiogram prior to the amputation (3). “Furthermore, patients who undergo a below the knee amputation have a five to 10 percent chance of dying before discharge from the hospital, and mean survival in a diabetic patient after major amputation is 27 months (4-7). So saving the leg not only improves quality of life, but it actually prolongs life,” he says.
Application of the angiosome concept has not been embraced broadly, and Huff believes it is due to a lack of education. “Things have changed a lot over the past five years in terms of peripheral intervention. We have more tools and more advanced techniques that allow us to be successful. I think there are a lot of wound care doctors and primary care doctors who don’t realize what we can do,” Huff says. “When I trained at the Cleveland Clinic, we worked hand-in-hand with podiatrists. We coupled wound care with revascularization and had fantastic outcomes.”
Huff says this team approach is necessary in order to be successful. “I can do a revascularization in a few hours, but it may take four weeks for the wound to completely heal. You need a team that can perform successful revascularization and then follow that up with aggressive wound care. Both are equally important,” he says. "There are a lot of people in health care who don’t understand this concept. To be honest, before I did a dedicated year of CLI training, I didn’t completely understand the importance of early and aggressive revascularization. There is a misconception that a patient should fail wound care and then be referred for revascularization as a last resort. This is the worst way to handle CLI, as it allows time for infection to propagate, often making amputation necessary regardless of whether revascularization can be performed. CLI is a ‘heart attack’ in the leg and should not be managed conservatively. I think we need to do a better job educating our patients with diabetes and end-stage kidney disease. In addition we need primary care doctors, wound care specialists, and podiatrists who can recognize this problem and refer patients for urgent evaluation.”
Huff suggests that physicians start by looking at their patients’ feet. “I am sure there are a lot of patients who don’t routinely have their socks and shoes taken off in the exam room. The first thing I do with every patient, regardless of what they are seeing me for, is touch their feet. For me, it’s just as important as listening to the heart,” he says. “But we need to recognize that the physical exam has limitations and be suspicious for CLI in our patients with diabetes and/or end-stage kidney disease who have a foot ulcer. CLI carries a five-year mortality rate of 67 percent, which is greater than MI, stroke, breast cancer and colorectal cancer (8-12). It’s a bad problem. If we don’t evaluate our patients appropriately and miss their CLI, we underestimate their risk of amputation and cardiovascular death.”
1) Rosinberg, A. (2011). Hemodynamic Evaluation of Peripheral Arterial Disease. In I. Casserly, R. Sachar, J. Yadav, Practical Peripheral Vascular Intervention (p. 8).Philadelphia, PA: Lippincott Williams & Wilkins.
2) Henry AJ, Hevelone ND, Belkin MB, et al. Socioeconomic and hospital-related predictors of amputation for critical limb ischemia. J Vasc Surg. 2011;53:330-9.e1.
3) Goodney PP, Travis LL, Nallamothu BK, et al. Variation in the use of lower extremity vascular procedures for critical limb ischemia. Cardiovasc Qual Outcomes. 2012;5:94-102.
4) Hasanadka R, McLafferty RB, Moore CJ, et al. Predictors of wound complications following major amputation for critical limb ischemia. J Vasc Surg. 2011;54:1374-1382.
5) Belmont PJ, Davey S, Orr JD, et al. Risk factors for 30-day postoperative complications and mortality after below knee amputation: a study of 2,911 patients from the national surgical quality improvement program. J Am Coll Surg. 2011;213:370-378.
6) Aulivola B, Hile CM, Hamdan AD, et al. Major lower extremity amputation: outcome of a modern series. Arch Surg. 2004;139:395-399.
7) Stone PA, Flaherty SK, Hayes JD, et al. Lower extremity amputation: a contemporary series. W V Med J. 2007;103:14-18
8) SEER Stat Sheets: Breast. National Cancer Center Institute Web site. http://seer.cancer.gov/statfacts/html/breast.html. April 24, 2013.
9) SEER Stat Sheets: Colon and Rectum. National Cancer Center Institute Web site. http://seer.cancer.gov/statfacts/html/colorect.html. April 24, 2013.
10) Weitz JI, Byrne J, Clagett GP, et al. Diagnosis and Treatment of Chronic Arterial Insufficiency of the Lower Extremities: A Critical Review. Circulation. 1996;94:3026-3049.
11) Hartman A, Rundek T, Mast H, et al. Mortality and cause of death after first ischemic stroke: the NorthernManhattan Stroke Study. Neurology. 2001;57:2000-20005.
12) Ljungman C, et al. Eur J Vasc Endovasc Surg. 1996; 11:176-182.