Long-term effects of baroreflex function after stenting in patients with carotid artery stenosis

Baroreflex sensitivity is recognized for its prognostic relevance to cardio-vascular and cerebro-vascular risks. However, little is known about the long-term outcome of baroreflex function in patients with carotid stenosis undergoing carotid stenting. Heart rate variability and cardio-vascular autonomic function, including baroreflex sensitivity, were examined using non-invasive methods in 22 adult patients who underwent carotid stenting. They were compared with the normal control group with 22 sex- and age-matched normal volunteers and the risk control group with 10 adult patients with severe stenosis or even total occlusion of the carotid artery without stenting. The groups of patients with stenting and risk controls had significantly reduced valsalva ratio and baroreflex sensitivity measured by the valsalva method compared to normal controls. However, there was no significant difference between patients with stenting and risk controls. There was significant decrease in heart rate response to deep breathing and to head-up tilt in patients with carotid stenting compared to normal controls. Other parameters of cardio-vascular autonomic function showed no difference among the three groups. Reduced baroreceptor function in patients with carotid stenting may be due to underlying diseases rather than the stenting itself. There was no short-term parasympathetic hyperactivity after the stenting, suggesting that the effect is transient rather than permanent.