BACKGROUND: According to the Vascular Disease Foundation, critical limb ischemia, or CLI, is a severe obstruction of the arteries that seriously decreases blood flow to the extremities (hands, feet and legs) and has progressed to the point of severe pain and even skin ulcers or sores. CLI is often present in individuals with severe peripheral arterial disease (PAD). The pain caused by CLI can wake an individual up at night. This pain, also called "rest pain," can be relieved temporarily by hanging the leg over the bed or getting up to walk around. CLI is a very severe condition of PAD and needs comprehensive treatment by a vascular surgeon or vascular specialist. This condition will not improve on its own. CLI can be attributed to a number of factors, including genetics, smoking, diet, cholesterol, diabetes and hypertension. Dr. Stanley Rockson from Stanford University said, "All of those factors that promote blood vessel disease anywhere in the body including specifically the disease of the heart will cause this."

LIMBS LOST: Patients with CLI don't get enough blood supply to the muscle and the skin in the legs. Rockson said, "These patients face nearly certain amputation. If you don't have enough blood supply, you can't carry oxygen to the tissues. You can't carry disease-fighting cells to the tissues. Nothing gets down there." Rockson said not only is the condition extremely painful, but it also provokes extreme anxiety. He said, "I can't stress enough how odious the concept is to a potential amputee, to think that they will lose the leg, even if we can guarantee them a well-fitting prosthesis. Just having a part of your body cut away forever is something that most people almost cannot appreciate as a realistic option."

NEW OPTION -- NEW HOPE: Rockson and his team at Stanford are involved in a trial of a novel gene therapy technique to treat CLI. The research is the first placebo-controlled study of its kind. They're testing the use of hepatocyte growth factor to stimulate vessel formation and re-establish blood flow in these limbs with blocked arteries. Unlike other gene therapies, which rely on partly disabled viruses to carry genes into human cells, the growth factor will be injected directly into the damaged tissue of the legs. Rockson said this unusual method should reduce some adverse effects sometimes caused by other gene therapy techniques. Rockson said past studies have suggested the delivery of growth factors can help improve blood flow, heal ulcers, minimize pain, and reduce the need for amputation. "This represents a new potential avenue for patients with little recourse besides amputation and death," he said. A small study in Japan actually showed the growth of new blood vessels with this technique, as well as an improvement in patients' symptoms. These results are what prompted the larger multi-center study. Rockson said he is excited to be involved in the research. He said, "It's like coming up with a cure for somebody who has widespread cancer, to use an analogy. Somebody that was previously considered untreatable is now treatable, and perhaps even curable."

FOR MORE INFORMATION, PLEASE CONTACT:
Dr. Stanley Rockson
Chief of Consultative Cardiology
Stanford University
Stanford, Calif.
srockson@cvmed.stanford.edu

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