CLEVER study

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Claudication: exercise versus endoluminal revascularization (CLEVER) study

A 67 year old non-diabetic man comes into the ED complaining of persistently nagging cramping pain in his right thigh after walking for a couple of blocks. He says that the pain goes away when he stops and rest for several minutes. Past medical history reveals that he is an ex-smoker with a 35 pack/year history. On physical exam, the femoral pulse are normal, but the popliteal and dorsalis pedis are diminished on the right leg. His ankle brachial index (ABI) is 0.98 on the left and 0.72 on the right. He is started on low dose aspirin and lipid lowering. What is the best initial management for this patient?

a)    Warfarin

b)   Heparin

c)    Enoxaparin

d)   Supervised exercise therapy

e)    Gemfimbrizil

f)     Pentoxifyline

g)    Arteriography followed by surgical bypass procedure

h)   CT angiography followed by stenting

i)     HMG-CoA reductase inhibitor

j)     Niacin

k)    Embolectomy

l)     Cholestyramine

m)  Colestipol

n)   Colesevelam

o) Reasurrance

p) increase to maximum dose aspirin

The patient mentioned in the above vignette has a clinical presentation that is consistent with the presence of peripheral arterial disease (PAD). PAD is a coronary artery disease equivalent. Medical research is very clear on this topic and includes briefings on aggressive risk factor modification with documented counseling for smoking cessation, lipid lowering therapy, and evaluation and treatment for hypertension and diabetes mellitus.

  • Interpretations of Ankle brachial index (ABI): An ABI between 0.9 and 1.2 considered normal (free from significant PAD), while a lesser than 0.9 indicates arterial disease. An ABI value greater than 1.3 is also considered abnormal, and suggests calcification of the walls of the arteries and incompressible vessels, reflecting severe PAD.

Since the vignette mentions that the patient has been started on low dose aspirin along with statin therapy. The next best step in management should be to enroll this patient in a supervised exercise program – according to the CLEVER study.

CLEVER STUDY

Background  Claudication is a common and disabling symptom of peripheral artery disease that can be treated with medication (i.e. statins etc…), supervised exercise (SE), or stent revascularization (ST).

Methods And Results  We randomly assigned 111 patients with aortoiliac peripheral artery disease to receive 1 of 3 treatments: optimal medical care (OMC), OMC plus SE, or OMC plus ST. The primary end point was the change in peak walking time on a graded treadmill test at 6 months compared with baseline. Secondary end points included free-living step activity, quality of life with the Walking Impairment Questionnaire, Peripheral Artery Questionnaire, Medical Outcomes Study 12-Item Short Form, and cardiovascular risk factors. At the 6-month follow-up, change in peak walking time (the primary end point) was greatest for SE, intermediate for ST, and least with OMC (mean change versus baseline, 5.8±4.6, 3.7±4.9, and 1.2±2.6 minutes, respectively; P<0.001 for the comparison of SE versus OMC, P=0.02 for ST versus OMC, and P=0.04 for SE versus ST). Although disease-specific quality of life as assessed by the Walking Impairment Questionnaire and Peripheral Artery Questionnaire also improved with both SE and ST compared with OMC, for most scales, the extent of improvement was greater with ST than SE. Free-living step activity increased more with ST than with either SE or OMC alone (114±274 versus 73±139 versus -6±109 steps per hour), but these differences were not statistically significant.

Conclusions  SE results in superior treadmill walking performance than ST, even for those with aortoiliac peripheral artery disease. The contrast between better walking performance for SE and better patient-reported quality of life for ST warrants further study.

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