High prevalence of exercise-induced ischemia in the asymptomatic limb of patients with apparently strictly unilateral symptoms and unilateral peripheral artery disease

Abstract

Background:: The prevalence of exercise-induced ischemia in the asymptomatic limb of patients with unilateral claudication based on history and treadmill evaluation, and with unilateral ipsilateral peripheral artery disease (i.e ankle-to-brachial systolic pressure index <0.90) is unknown.

Methods:: We detected exercise-induced ischemia in the asymptomatic limb of patients with apparently unilateral claudication. Among 6059 exercise-oximetry tests performed in 3407 nondiabetic and 961 diabetic patients. We estimated the intensity of ischemia in the both limb (buttocks and calves) using the lowest minimum value of the decrease from rest of oxygen pressure (DROP; limb changes minus chest changes from rest), with significant ischemia defined as DROP lower than -15 mmHg.

Results:: We found 152 tests performed in 142 nondiabetic patients and 40 tests performed in 38 diabetic patients. The asymptomatic limb showed significant ischemia in 46.7% and 37.5% of the tests. Strictly unilateral exercise-induced claudication with apparently unilateral peripheral artery disease was rare (<4% of all tests). However, among these highly selected tests, significant ischemia was found in the asymptomatic limb in more than one-third of cases.

Conclusion:: The asymptomatic limb of patients with peripheral artery disease should not be considered a normal limb.

Keywords: claudication; diabetes mellitus; exercise; lower limb; transcutaneous oxygen pressure; treadmill testing; walking impairment.

Figure 1.

Illustration of the recording procedure. The Gray square is the walking period. In the upper left corner is a zoom on one probe fixed to the calf. Middle panels are results in absolute values on the 8 probes. Note from the lower panel that only the left calf reached significance. Also note on the lower panel, that the DROP min may occur either during (buttocks and left thigh) or following (calves and right thigh) the walking period.

Figure 2.

Flow diagram of the patients in this analysis.

Figure 3.

Typical example of the exercise oximetry of one of the 180 selected patients (upper panel). This non-diabetic 54-year-old female patient demonstrated unilateral right proximo-distal claudication via history and treadmill evaluation. ABI was 0.6 for the right limb and 1.0 for the left limb. An angioscan showed severe stenoses of the internal and external right iliac arteries(left middle panel) treated by angioplasty (right middle panel), and mild to moderate femoro-popliteal bilateral lesions As illustrated in the upper panel, exercise-oximetry showed significant buttock and severe thigh and calf ischemia and a significant asymptomatic contralateral calf ischemia. The grey rectangle corresponds to the walking period. In this patient, a recording was also available 3 months after angioplasties of iliac stenoses. Although not selected in the 192 finally selected tests, this second recording is of interest to show the effect of internal and external right angioplasty on exercise oximetry results (lower panel). Interestingly, the left calf ischemia seemed less pronounced than before revascularization, possibly as a result of regular training in this active patient.