Extracranial Internal Carotid Artery Tortuosity and Body Mass Index

Extracranial internal carotid artery (eICA) tortuosity may trigger cerebral ischemia, and body mass index (BMI) is a measure of body mass based on height and weight. The main purpose of this study is to determine the influence of BMI on the tortuosity of eICA.

A total of 926 carotid artery angiograms were performed in 513 patients, of which 116 cases and matched controls were selected. Arterial tortuosity was defined as simple tortuosity, kinking, or coiling. The severity of tortuosity was measured by tortuosity index, formula: [(actual length/straight-line length - 1) × 100].

BMIs were different between the two groups [tortuosity: 27.06 kg/m² (SD 2.81 kg/m²) versus none: 23.3 kg/m² (SD 2.78 kg/m²); p < 0.001]. BMI was independently and significantly associated with eICA tortuosity (odds ratio 1.59; 95% confidence interval, 1.35-1.86; p < 0.001). eICA tortuosity index is linearly associated with BMI (exponential coefficient β = 1.067, p < 0.001). The optimal predictive threshold of BMI for eICA tortuosity was 25.04 kg/m². The physiological mechanism underlying the reasons why higher BMI has negative influence on extracranial carotid artery tortuosity may be an intra-abdominal hypertension caused by a much higher amount of body fat stored in visceral adipose tissue.

Our result reveals a novel role for greater BMI on the presence of eICA tortuosity. For each increase in BMI of 1 kg/m², there is a corresponding 1.59-fold increase in the risk of developing eICA tortuosity. The severity of eICA tortuosity increases linearly with increased BMI.