Peripheral vascular disease (PVD) of the lower extremities, also known as peripheral arterial disease (PAD), is a result of generalized atherosclerosis, and is associated with increased mortality, even in asymptomatic patients. In patients over the age of 60, the prevalence of PAD is estimated at 15% and claudication occurs in up to 5%.
A recent study suggests that a relatively simple test, the ankle brachial index (ABI), is more closely associated with leg function in patients with PAD than is intermittent claudication or other leg symptoms.
The study involved 740 men and women, 460 with PAD. Leg function was determined using accelerometer-measured physical activity over seven days, 4-metre walking velocity, standing balance and ABI. Of the 460 people with PAD, only 33% had intermittent claudication. However, compared with an ABI of 1.1 to 1.5, an ABI of less than 0.50 was associated with a shorter distance walked in six minutes, less physical activity, slower 4-metre walking velocity and less likelihood of maintaining a tandem stand for 10 minutes. The associations between leg function and ABI were stronger than were associations between leg symptoms and function.
Unfortunately, the ABI is not 100% accurate in detected PAD. In addition, in this study, many of the patients with PAD were recruited from specialized centres where they are referred for suspected PAD--people with unrecognized PAD may have different findings than do those specifically referred for diagnostic evaluation of PAD.
Nonetheless, the evidence suggests that the ABI, a simple and inexpensive procedure, is more closely associated with leg function in persons with PAD than is either intermittent claudication or leg symptoms.
Source
- McDermott M, Greenland P, Liu K et al. The ankle brachial index is associated with leg function and physical activity: The Walking and Leg Circulation study. Ann Internal Med 2002; 136:873-83.
