Superficial Femoral Artery Plaque and Functional Performance in Peripheral Arterial Disease: Walking and Leg Circulation Study (WALCS III)

Study Questions:

What is the association between magnetic resonance imaging measurements of plaque area and relative percent lumen reduction in the proximal superficial femoral artery with functional performance among participants with peripheral arterial disease (PAD)?


A total of 454 participants with an ankle brachial index (ABI) <1.00 underwent magnetic resonance cross-sectional imaging of the proximal superficial femoral artery and completed a 6-minute walk test, measurement of 4 m walking velocity at usual and fastest pace, and measurement of physical activity with a vertical accelerometer. Six-minute walk performance, usual-paced and fastest-paced 4 m walking velocity, and physical activity levels were compared across quintiles of each plaque measure using analyses of covariance, adjusting for age, race, sex, smoking, body mass index (BMI), statins, and comorbidities.


Adjusting for age, sex, race, BMI, smoking, statin use, comorbidities, and other covariates, higher mean plaque area (first quintile [least plaque]: 394 m, second quintile: 360 m, third quintile: 359 m, fourth quintile: 329 m, fifth quintile [greatest plaque]: 311 m; p trend < 0.001) and smaller mean percent lumen area (first quintile [greatest plaque]: 319 m, second quintile: 330 m, third quintile: 364 m, fourth quintile: 350 m, fifth quintile: 390 m; p trend < 0.001) were associated with shorter distance achieved in the 6-minute walk test. Greater mean plaque area was also associated with slower usual-paced walking velocity (p trend = 0.006) and slower fastest-paced 4 m walking velocity (p trend = 0.003). Associations of mean plaque area and mean lumen area with 6-minute walk distance remained statistically significant even after additional adjustment for the ABI and leg symptoms.


The authors concluded that greater plaque burden and smaller lumen area in the proximal superficial femoral artery are associated independently with poorer functional performance.


The study suggests that among participants with PAD, greater mean and maximum plaque area and smaller percent minimum lumen area in the proximal superficial femoral artery are associated significantly and independently with poorer functional performance, even after adjusting for the ABI. These findings should not be interpreted as a recommendation for additional diagnostic testing or interventions, as compared with current clinical practice in patients with PAD. Further study is needed to determine whether interventions that reverse plaque burden can improve functional performance in PAD.

Clinical Topics: Diabetes and Cardiometabolic Disease, Noninvasive Imaging, Prevention, Vascular Medicine, Atherosclerotic Disease (CAD/PAD), Magnetic Resonance Imaging, Exercise, Smoking

Keywords: Coronary Artery Disease, Plaque, Atherosclerotic, Ankle Brachial Index, Femoral Artery, Comorbidity, Peripheral Arterial Disease, Risk Factors, Lower Extremity, Magnetic Resonance Imaging, Peripheral Vascular Diseases, Smoking, Walking, Body Mass Index, Magnetic Resonance Spectroscopy, Exercise Test

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