Muscle sympathetic outflow in Buerger's disease.

One of the pathophysiological features in Buerger's disease, i.e. thromboangiitis obliterans (TAO), contains a sympathetic contribution which relates to vasospastic phenomenon. The purpose of this study is to clarify sympathetic mechanisms in TAO. Muscle sympathetic nerve activity (MSA) was recorded using a microneurographic technique in patients suffering from TAO. The cold pressor test (by immersing the hand of the subject into ice cold water) was used as a test to examine the sympathetic responsiveness to local cold stimulus. The basal level of the MSA in the TAO group was lower than that in the control group (control group vs. TAO group: 39.8 +/- 12.8 bursts/min vs. 26.1 +/- 12.1 bursts/min in burst rate, P < 0.05, 61.8 +/- 8.3 bursts/100 heart beats vs. 39.5 +/- 22.3 bursts/100 heartbeats in burst incidence, P < 0.05). The responsiveness of MSA to the cold pressor test in the TAO group was higher than that in the control group (TAO group vs. control group: 385 +/- 191% total MSA vs. 198 +/- 156% total MSA, P < 0.05). We directly demonstrated higher responsiveness of MSA to the local cold stimulus in patients with TAO. This hyperresponsive MSA might contribute to the pathophysiologic feature in TAO.