Morphological variations of the internal carotid artery: Prevalence, characteristics and association with cerebrovascular disease

The prevalence of internal carotid artery (ICA) morphological variations (MV), their characteristics, and their possible association with carotid stenosis, vascular risk factors, and previous transient ischemic attack or ischemic stroke was investigated in a consecutive series of patients.Within a seven-month period, 1217 patients (557 men and 660 women; mean age [± SD] 62.7±18.1 years) consecutively referred to the Laboratory of Neurosonology, University of L'Aquila, Italy, underwent a neck vessel examination using a high-resolution B-mode ultrasound device with a 7.5 MHz linear phased array probe.ICA MV were present in 319 (26.2%) patients; they were unilateral in 201 patients (63.0%) and bilateral in 118 patients (37.0%). Patients with ICA MV were older than those without ICA MV (66.3±19.9 years versus 61.4±18.0 years, P<0.0001) and were mostly women (62.4%, P=0.0008). Tortuosity was present in 195 (44.6%) arteries, kinking in 236 arteries (54.0%) and coiling in six arteries (1.4%). Carotid stenosis was found in 270 patients (22.2%). Among patients with ICA stenosis, MV were found in 134 patients (49.6%). Mean neck length was similar in patients with and without ICA MV (12.1±2.4 cm versus 12.6±2.9 cm, P=0.4). In the multivariate logistic regression analysis, the presence of ICA MV was associated with female sex and older age.Tortuosity and kinking were frequently encountered during neurovascular examination. Their presence was usually related to aging and female sex, and did not imply any additive risk for stroke, although further studies are needed to clarify this point.