Endovascular Therapy's Role In Diabetic Limb Ischemia

By  Mark S. Lesney

CHICAGO -- Endovascular techniques showed promise for restoring circulation in a small study of 50 diabetic patients with limb-threatening conditions presented by Joseph L. Mills, M.D., at the Vascular Annual Meeting.

Dr. Mills

In an earlier study, Dr. Mills noted that with open-surgical revascularization, diabetic patients showed prolonged recovery times and significant delays in wound healing, compared with nondiabetic patients, and that some of those wounds were caused by the bypass graft itself. This led him to see if less-invasive revascularization techniques could be utilized.

Even though angioplasty techniques may not offer the same long-term patency as traditional open surgical bypass, it is important to remember the rationale for revascularization, he said. In the case of diabetic patients, the critical goal of therapy is saving the foot from amputation.

"You may be able to accomplish revascularization percutaneously such that the foot heals. If that intervention fails, but the foot stays healed, that is a victory. On the other hand, if a surgical bypass remains patent but the wounds you created to do the bypass fall apart and prolong patient recovery, or if the bypass fails to prevent amputation, the procedure would be a failure despite graft patency," said Dr. Mills, chief of vascular surgery at the University of Arizona, Tucson.

This preliminary, nonrandomized study involved 50 consecutive diabetic patients with limb-threatening conditions treated by Dr. Mills. Among patients who required revascularization, 48% were treated endovascularly and 52% with open bypass surgery. An initial endovascular approach was performed on 17 patients. Only 3 required conversion to open surgery; the others were successfully revascularized by endovascular means alone. All study patients had infrainguinal occlusive disease and a signficiant number had tibial artery lesions.

A total of 15 patients required distal bypass, 12 as the primary procedure and 3 after endoluminal revascularization proved inadequate. Only two legs were lost to amputation: One was lost as the result of a chronic methicillin-resistant Staphylococcus aureus infection in a patient with a patent tibial bypass; the other was a primary amputation done on a frail, high-risk patient who was minimally ambulatory, according to Dr. Mills.

To illustrate how the degree of patient debility fails to preclude a successful endovascular approach, Dr. Mills detailed a typical case--an 82-year-old diabetic man with toe gangrene, who had undergone a kidney transplant and a coronary bypass, was hyperlipidemic and hypertensive, and had a contrast allergy. Prior to treatment, his great toe waveform was flat, with no toe pressure; after tibial angioplasty, the patient's toe pressure rose to 38 mm Hg, and major amputation was prevented.

Dr. Mills believes that endovascular techniques may be an alternative to open surgical bypass in protecting the diabetic foot in patients with appropriate vascular anatomy, although he stressed that this is based on short-term data on his own patients.

He intends to gather long-term outcome data on these patients, with the ultimate goal of identifying which patients would benefit most from endovascular techniques and which from traditional open surgery.