Pulsatility Index at the Cervical Internal Carotid Artery as a Parameter of Microangiopathy in Patients With Type 2 Diabetes

OBJECTIVE: Although carotid intima-media thickness is a well-recognized indicator of atherosclerosis, it may not be an appropriate indicator of microangiopathy. We evaluated the parameters of extracranial carotid artery (CA) duplex ultrasonographic scanning in relation to microalbuminuria, which is an indicator of microangiopathy in patients with diabetes. The relationships of CA stenosis, hypertension, and dyslipidemia with microalbuminuria were also evaluated. METHODS: Among 234 patients who were hospitalized for controlling type 2 diabetes during a 20-month period, those with major cerebrovascular, cardiac, or renal disease were excluded, leaving 159 patients who did not have any acute symptoms enrolled in this cross-sectional study. The parameters of extracranial CA duplex ultrasonographic scanning and urine albumin-to-creatinine ratio (u-ACR) were extracted, and their relationships were analyzed. Each patient's status with regard to CA stenosis, hypertension, and dyslipidemia was also examined for the effects on u-ACR. RESULTS: Of the 159 patients, 29 (18.2%) had some CA stenosis, and there were significantly more hypertensive patients in this group (P=.007). The value of u-ACR was significantly higher in patients with dyslipidemia (P<.001) but not in those with CA stenosis or hypertension. With univariate analysis, significant correlations of u-ACR were observed with age, right end-diastolic velocity, and the bilateral pulsatility index (PI). Among these factors, multivariate analysis was made, and only age and PI proved to be independent factors correlated with u-ACR (P<.0001). With a PI cutoff of 1.15, 89.3% specificity with 49.1% sensitivity was obtained for detecting microalbuminuria. CONCLUSIONS: The PI at the cervical internal CA can indicate microangiopathy because of its strong correlation with microalbuminuria in patients with type 2 diabetes, and it is thought to reflect the microangiopathy of cerebral vessels.