Preservation of skin vasoconstrictor responses in chronic atherosclerotic peripheral vascular disease

Peripheral neuropathy is often found in ischemic limbs with nondiabetic atherosclerotic peripheral vascular disease (PVD). Sensory symptoms such as burning pain are common in severely ischemic limbs, and sympathectomy has been undertaken for ischemic rest pain. The authors assessed noninvasive quantitative skin vasomotor reflexes in toes and standard systemic cardiovascular autonomic tests in 44 PVD subjects with varying severity of limb ischemia, 30 age-matched control subjects, and nine PVD subjects associated with diabetes. Skin vasoconstrictor reflexes to inspiratory gasp, Valsalva maneuver, and postural change, and the postischemic reactive hyperemic response, were evaluated by the measurement of skin blood flow on toe pads by use of a laser Doppler flowmeter. Vasoconstrictor responses were not significantly different between PVD toes, even in severely ischemic limb, and age-matched controls. Reactive hyperemia was significantly less in PVD than in controls. Cardiovagal and systemic vasoconstrictor reflexes were also evaluated. All PVD subjects showed normal systemic cardiovascular reflexes. In contrast, these reflexes were severely impaired in diabetic PVD. The authors demonstrated that skin vasoconstrictive sympathetic reflex is preserved in chronically ischemic limbs with PVD, suggesting that sympathetic nerve fibers are relatively resistant to chronic ischemia.