Changing associations between progressive cardiovascular autonomic neuropathy and carotid atherosclerosis with increasing duration of Type 2 diabetes mellitus

To clarify associations between cardiovascular autonomic neuropathy (CAN) and the progression of carotid artery atherosclerosis in Type 2 diabetic patients, cardiovascular autonomic nerve function was related to carotid artery ultrasound in 61 Type 2 diabetic patients, 5 and 8 years after the diagnosis of diabetes. Between 5 and 8 years after diagnosis, age-adjusted acceleration index (AI) decreased (from −0.306±1.034 to −0.702±1.072; P=.0139), whereas age-adjusted expiration/inspiration (E/I) ratio was unchanged (−0.583±1.038 and −0.828±1.028; P=.1164). Intima-media thickness (IMT) increased in both the common carotid artery (CCA; from 0.854±0.219 to 0.913±0.241 mm; P<.0001) and the carotid bulb (from 1.789±0.714 to 2.128±0.881 mm; P<.0001), corresponding to a yearly IMT increase of 0.032±0.039 mm in the CCA and 0.146±0.204 mm in the carotid bulb. This value did not correlate with the AI or E/I ratios. In age-controlled partial correlation in the first examination, AI correlated inversely with mean (r=−.33, P=.018) IMT in the CCA, but not with IMT in the carotid bulb (r=−.14, P=.303). However, in contrast to the first examination, at follow-up, AI correlated inversely with the mean IMT of the carotid bulb (r=−.40, P=.007), lumen diameter of the CCA (r=−.31, P=.034), and plaque score (r=−.29, P=.041), but not with IMT of the CCA (r=−.04, P=.861). There were no correlations between the E/I ratio and carotid variables. In conclusion, CAN was associated with features of carotid atherosclerosis, which, in the carotid bulb, might affect baroreceptor function with the progression of Type 2 diabetes.