Current Concepts In Treating Ischemic Foot Ulcers
When it comes to patients with ischemic foot ulcers, potential complications can be dire. Accordingly, it is important to have a firm grasp on diagnostic studies as well as current and emerging treatment options that may enhance outcomes for patients. With this in mind, our expert panelists discuss a range of issues related to the ischemic foot. Q: How do you approach/work up the ischemic foot ulcer patient? A: David E. Allie, MD, works up such patients “very, very aggressively.” Of the approximately 180,000 to 200,000 annual amputations in the U.S., he notes that between 80 and 85 percent are preceded by an ischemic diabetic foot ulcer (DFU). Research indicates that following a below- or above-knee amputation, half of the patients will survive for three years and less than half will achieve mobility. Since these patients may die from heart attacks and strokes, Dr. Allie says he initially performs a quick (5- to 10-minute) cardiac-carotid-renal-diabetic history and exam before he turns his attention to the foot. These patients will need revascularization so he will immediately start ASA 325 mg, Plavix 75 mg, antibiotics after C&S, and Metanx (Pam Lab) po bid. In regard to Metanx, he is “impressed” that its combination of vitamin B-6, B-12 and folic acid spurs wound healing by lowering homocysteine levels.1 For Marc Brenner, DPM, the most important steps are the history and physical exam. He says the exam must include palpating all pulses, assessing for capillary return and venous filling time, and, most significantly, obtaining the ankle-brachial index (ABI). If he cannot initially palpate pedal pulses, Lawrence Karlock, DPM, will perform an arterial Doppler test with absolute toe pressures. Even when one is facing calcified lower extremity vessels, Dr. Karlock says absolute toe pressures may provide an accurate account of arterial inflow. When it comes to treating foot ulcers, if one or both pedal pulses is not palpable, Mehrdad Zarrinmakan, MD, says an arteriogram is indicated. If pedal pulses are palpable, he says one should perform arterial studies. Q: What value do noninvasive arterial studies play in the diagnosis? A: Noninvasive arterial studies in patients with diabetes, with or without ulcerations, should be part of every practitioner’s approach, according to Dr. Brenner. He adds that podiatric physicians should measure ABIs and duplex scanning routinely for patients with diabetes. Dr. Zarrinmakan likewise cites the importance of arterial studies, calling them “important and relatively inexpensive.” He says physiologic testing plays a major role in the diagnosis and follow-up of patients. Dr. Allie immediately obtains the ABI and arterial duplex ultrasound to confirm but not completely localize all involved diseased vessels. Simultaneously, in one office visit, he obtains noninvasive studies, including carotid ultrasound, echocardiography and cardiac nuclear imaging, if indicated, to access the entire cardiovascular system. Dr. Allie notes having a low threshold for early hospital admission for patients with critical limb ischemia (CLI) and emphasizes intravenous anticoagulation, antibiotics and renal hydration, which prepare them for revascularization. Dr. Allie also obtains appropriate consultations with podiatry, cardiology, endocrinology and other specialists. Although noninvasive arterial studies provide a general overview of the vascular inflow, Dr. Karlock says they can be misleading in some instances. He says a normal test will usually exclude any significant peripheral vascular disease (PVD). Q: When do you consider arteriography? When do you consider a magnetic resonance arteriogram (MRA)? A: Dr. Brenner calls ABIs of less than 0.6, along with rest pain and/or lesions, discoloration or claudication, “a red flag” for immediate referral to an appropriate PVD specialist. Following ABI and duplex scanning, a vascular surgeon would usually undertake MRA, CTA and a DS angiogram, according to Dr. Brenner. After performing these diagnostic tests, he says the vascular surgeon would usually perform interventional endovascular procedures as an alternative to bypass or possibly in conjunction with it. Dr.