Vascular tortuosity may be related to intracranial artery atherosclerosis

Background: Conventional risk factors cannot explain the individual or ethnic difference in the location of cerebral atherosclerosis. Vascular geometry may play a role on this.

Aim: To investigate the association between the geometrical properties of the middle cerebral artery and intracranial atherosclerosis.

Methods: Stroke patients with either symptomatic middle cerebral artery or proximal internal carotid artery diseases were enrolled. The diameter, length, and tortuosity (arc-chord ratio, by percent) of the middle cerebral artery was compared between stroke patients and the age- and gender-matched healthy subjects. The geometrical property was also compared between the symptomatic middle cerebral artery and the normal-looking contralateral middle cerebral artery, and between the contralateral middle cerebral arteries in patients with symptomatic middle cerebral artery and proximal internal carotid artery diseases.

Results: One hundred seventy-seven patients (101 with middle cerebral artery disease and 76 with proximal internal carotid artery disease) were studied. Symptomatic middle cerebral artery was more tortuous (119·31 ± 16·95 vs. 112·98 ± 14·16; P = 0·009) than the contralateral middle cerebral artery. The contralateral middle cerebral artery of patients with symptomatic middle cerebral artery disease demonstrated a smaller proximal diameter (P = 0·007) and a greater vascular tortuosity than the contralateral middle cerebral artery of patients with proximal internal carotid artery disease (112·01 ± 12·25 vs. 107·46 ± 9·35; P = 0·008) and corresponding middle cerebral artery of healthy control subjects (112·01 ± 12·25 vs. 108·73 ± 9·79; P = 0·04). Young age, female, small diameter, the absence of diabetes, and high tortuosity of the contralateral middle cerebral artery were independently associated with middle cerebral artery atherosclerotic disease.

Conclusions: High tortuosity and small diameter are related to middle cerebral artery atherosclerosis, probably by altering hemodynamics. Different degree of tortuosity may be one of the reasons for individual differences in location of cerebral atherosclerosis.