CLEVER Compares Stenting and Supervised Exercise to Improve Walking Ability of Patients With Leg Claudication

November 16, 2011—The American Heart Association (AHA) announced that findings from the CLEVER (Claudication: Exercise Versus Endoluminal Revascularization) study suggest that in patients on standard therapy for blocked leg vessels, adding a supervised treadmill exercise program improved walking ability significantly better than stenting. Patients on either additional therapy improved walking ability better than standard therapy alone, which is home walking and cilostazol.

The study was presented at the AHA's annual scientific sessions in Orlando, Florida, and published online ahead of print by Timothy Murphy, MD, et al in the AHA journal, Circulation. The National Heart, Lung, and Blood Institute sponsored the CLEVER study.

According to the AHA, claudication has been treated with supervised exercise, medications, or angioplasty and stent placement. However, the relative effectiveness of each type of treatment was unclear; the use of stents has increased, and exercise is not often used.

The investigators began the study in February 2007. The current report described the primary 6-month study outcome. All patients will continue to receive follow-up for 18 months to evaluate more long-term outcomes, quality of life, and cost-effectiveness. The study will conclude in January 2012.

As detailed by the AHA, the CLEVER study enrolled 111 peripheral arterial disease (PAD) patients from 29 centers in the United States. The patients' average age was 64 years, 61% were male, and 80% were Caucasian. More than 50% of the patients smoked, and approximately 25% had diabetes.

The 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. At 6 months after 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 plus cilostazol), 3.7 minutes (stents plus cilostazol), and 1.2 minutes (home exercise plus cilostazol).

“The evidence shows that those who receive the usual medical care do not enjoy a substantial improvement in their symptoms at all,” commented Dr. Murphy. “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. I think that both of these therapies offer substantial advantages over the usual care."

Patients in both the supervised exercise and stent groups scored better on a variety of quality-of-life measurements. 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. Exercise treatment improved leg function and symptoms, but not blood flow to the leg.

The study's Chair, Alan T. Hirsch, MD, remarked, “Perhaps this should not be surprising at all. 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.”