Peroneal nerve damage contributes to functional impairment in PAD
MedWire News: Poor peroneal nerve function is associated with reduced calf muscle size and walking ability in patients with peripheral arterial disease (PAD), study findings show.
Patients with PAD may experience calf muscle pathologic changes including denervation but the impact on lower extremity nerve function and calf muscle area and density have not been determined, explain Mary McDermott (Northwestern University, Chicago, Illinois, USA) and co-workers.
To investigate further, the team conducted electrodiagnostic testing of the peroneal nerve in 413 patients with a PAD, defined as an ankle-brachial index (ABI) below 0.90, and compared their results with 255 patients without the condition. In all, 130 PAD patients and 59 controls had Type 2 diabetes.
Computed tomography was performed two-thirds of the way between the distal and proximal tibia to determine calf muscle cross-sectional area and percentage fat, and the participants were asked to complete a 6-minute walk.
Analysis showed that in PAD patients without diabetes, low peroneal nerve conduction velocity (NCV) was significantly associated with lower calf muscle area (4770 vs 5571 mm2 for first versus fourth quartile), and a poorer 6-minute walk distance (989 vs 1211 feet [301 vs 369 m]), after adjusting for factors including age, gender, race, ABI, smoking, and comorbidity.
Similarly, in patients with PAD plus diabetes, lower peroneal NCV was associated with lower calf muscle area (5166 vs 6003 mm2) and shorter 6-minute walk distance (866 vs 1082 feet [264 vs 330 m]).
Lower peroneal NCV was associated with shorter 6-minute walk distance in controls without diabetes (1317 vs 1570 feet [401 vs 479 m]) but not in controls with diabetes. NCV was not significantly associated with lower calf muscle area in controls, regardless of diabetes status.
"Poor lower extremity nerve function is associated with more-unfavorable calf muscle characteristics and greater functional impairment in participants with PAD, even after adjusting for PAD severity," McDermott et al summarize in the Journal of the American Geriatric Society.
"Future longitudinal studies should focus on establishing the role of calf muscle characteristics in the relationship between lower extremity nerve function and functional performance and determine whether peripheral neuropathy contributes to the causal pathway for functional decline in PAD individuals."
By Lynda Williams