Impairments of muscles and nerves associated with peripheral arterial disease and their relationship with lower extremity functioning: The InCHIANTI Study

OBJECTIVES: To define the relationships between lower extremity peripheral arterial disease (PAD), pathophysiological findings in lower extremity muscles and nerves, and lower extremity performance. DESIGN: Cross-sectional. SETTING: Two communities in Italy. PARTICIPANTS: Nine-hundred seventy-nine community-dwelling men and women aged 60 and older (109 with PAD). MEASUREMENTS: Presence and degree of lower extremity arterial obstruction were determined using the ankle-brachial index (ABI). Lower extremity muscle cross-sectional area was measured using computed tomography. Peroneal nerve conduction velocity (NCV) and leg power were also determined. Measures of lower extremity functioning were fast walking speed over 4 meters, time required to walk 400 meters, and the summary performance score. RESULTS: Participants with PAD had significantly poorer performance on functional outcomes than participants without PAD. Adjusting for age and sex, presence of PAD was associated with reduced leg muscle power (83.69 vs 103.51 watts, P<.001), reduced muscle cross-sectional area (61.5 vs 63.5 cm(2), P=.14), and reduced NCV (43.0 vs 44.2 m/s, P=.003). Adjustment for leg power diminished the independent association between ABI and the functional outcomes measures. CONCLUSION: In community-dwelling individuals, PAD is associated with reduced NCV and reduced muscle power in the lower extremities. Muscle power may mediate the association between lower ABI levels and poorer functional performance.