ORLANDO, FLA. — In patients on standard therapy for blocked leg vessels, adding a supervised treadmill exercise program improved walking ability significantly better than stenting, according to late-breaking research presented at the American Heart Association’s Scientific Sessions 2011.
Patients on either additional therapy improved walking ability better than standard therapy alone, which is home walking and cilostazol, a medicine that improves blood flow to the legs.
The study, called CLaudication: Exercise Vs Endoluminal Revascularization Study (CLEVER), is also published in Circulation: Journal of the American Heart Association.
About 9 million people in the United States have clogged blood vessels to the legs, or peripheral artery disease (PAD). More than 2 million of these patients suffer from leg muscle pain with exercise. This symptom, called claudication, can severely limit mobility.
Patients and physicians have treated claudication with either supervised exercise, medications, or angioplasty and stent placement. Until now, however, the relative effectiveness of each type of treatment was unclear. The use of stents has increased, and exercise is not often used.
Investigators randomized patients to home walking plus cilostazol or to the same approach plus one of two other interventions: supervised treadmill exercise or placement of a stent to reduce narrowing in the iliac artery, a large blood vessel supplying blood to the leg. Stents are most effective for PAD when used at this anatomic site.
Six months after study enrollment, patients in the supervised exercise program significantly increased their treadmill walking time, as did those who received stents. In contrast, patients who only exercised at home showed little improvement.
The average walking time in each group improved by:
- 5.8 minutes ─ supervised exercise + cilostazol;
- 3.7 minutes ─ stents + cilostazol;
- 1.2 minutes ─ home exercise + cilostazol.
“The evidence shows that those who receive the usual medical care do not enjoy a substantial improvement in their symptoms at all,” said Timothy Murphy, M.D., study lead author and professor in the diagnostic-imaging department at the Warren Alpert Medical School of Brown University in Providence, R.I.
Patients in both the supervised exercise and stent groups scored better on a variety of quality of life measurements. Surprisingly, however, patients in the stent group described a better quality of life compared to both the supervised- or home-exercise programs. The reasons for the dissociation between treadmill walking and quality of life improvements are not clear.
“It is important to note that both the supervised exercise and stent treatments provided substantially more benefit than usual home-based medical care, and both are proven to be effective treatments,” Murphy said. “I think that both of these therapies offer substantial advantages over the usual care.”
Exercise treatment improved leg function and symptoms, but not blood flow to the leg.
“Perhaps this should not be surprising at all,” said Alan T. Hirsch, M.D., chair of the study and professor of medicine, epidemiology and community health in the Lillehei Heart Institute of the University of Minnesota in Minneapolis. “Leg function can improve tremendously in almost any individual without any increase in blood flow past major artery blockages, as walking efficiency is dependent on much more than one blocked artery. Exercise is known to improve leg function and symptoms in numerous proven ways. Microscopic blood vessels that supply leg muscles and the nerves and muscles themselves all become much more efficient.”
The study enrolled 111 PAD patients, average age 64 years, from 29 centers in the United States. Sixty-one percent were male, and 80 percent were Caucasian. More than half smoked and nearly one-fourth had diabetes. Smoking and diabetes are powerful risk factors for PAD.
Researchers began the study in February 2007 and this report described the primary 6-month study outcome. All patients will continue to receive follow-up for a full 18 months to evaluate more long-term outcomes, quality of life and cost-effectiveness. The study will conclude in Jan. 2012.
Co-authors are Don Cutlip, M.D.; Judy Regensteiner, Ph.D.; Emile Mohler, M.D.; Suzanne Goldberg, R.N.; Joe Massaro, Ph.D.; David Cohen, M.D.; Matt Reynolds, M.D.; Beth Lewis, Ph.D.; Joselyn Cerezo, M.D.; Niki Oldenburg and Claudia Thum.
Disclosures are here: http://newsroom.heart.org/pr/aha/document/Disclosures_for_LBCT.xlsx.
The National Heart, Lung, and Blood Institute funded the study.
Statements and conclusions of study authors that are presented at American Heart Association scientific meetings are solely those of the study authors and do not necessarily reflect association policy or position. The association makes no representation or warranty as to their accuracy or reliability. The association receives funding primarily from individuals; foundations and corporations (including pharmaceutical, device manufacturers and other companies) also make donations and fund specific association programs and events. The association has strict policies to prevent these relationships from influencing the science content. Revenues from pharmaceutical and device corporations are available at www.heart.org/corporatefunding.
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