[Evaluation of the level of carotid bifurcation and the morphology of extracranial internal carotid artery in patients with carotid stenosis by color doppler ultrasound and digital subtraction angiography].

Objective: To evaluate the value of color Doppler ultrasound and digital subtraction angiography (DSA) in evaluating the level of carotid bifurcation and the morphology of extracranial internal carotid artery in patients with atherosclerotic carotid stenosis. Methods: The carotid artery examination data of 186 patients with atherosclerotic carotid stenosis who underwent carotid DSA and color Doppler ultrasound in Shanghai Changzheng Hospital from July 2017 to June 2019 were retrospectively analyzed, including 154 males and 32 females, with ages ranging from 36 to 84 (66±8) years old. The correlation between the position of carotid bifurcation and the level of cervical spine, the distance from the position of carotid bifurcation to mandibular angle, the correlation of the level of bifurcation with the length of neck, and the incidence of carotid distortion were analyzed. Results: DSA showed that the most common position of carotid bifurcation was at C3 level on the left [37.3% (56/150)], and at C3-C4 level on the right [33.6% (42/125)], and the highest position was at C2 level on the left, and at C2-C3 levels on the right, while the lowest level on both sides was at C5 level. The incidence of high bifurcation of left carotid artery (C3 and above) was 46% (69/150), which was higher than that of right carotid artery [21.6% (27/125), P<0.001]. The incidence of high carotid bifurcation in men and women was 33.2% (76/229) and 43.5% (20/46), respectively, with no significant difference (P = 0.182). Carotid ultrasound showed that the distance between the left carotid bifurcation and the mandibular angle was (3.0±1.3) cm, which was shorter than that on the right [(3.4±1.2) cm] (P<0.001). The distance between carotid bifurcation and mandibular angle in men and women was (3.2±1.2) cm and (3.3±1.0) cm, respectively, with no significant difference (P = 0.093). There was no significant correlation between carotid bifurcation level and carotid length (right: r = 0.02, P = 0.091; left: r = 0.01, P = 0.927). The incidence of carotid artery distortion was 28.1% (9/32) in women and 15.6% (24/154) in men, with no significant difference (P = 0.091). The incidence of right carotid artery distortion in high bifurcation group was 59.3% (16/27), which was higher than that in non-high bifurcation group [3.1% (3/98)] (P<0.001). Likewise, the incidence of left carotid artery distortion in high bifurcation group was 30.4% (21/69), which was higher than that in non-high bifurcation group [2.5% (2/81)] (P<0.001). Conclusions: The bifurcation position of left carotid artery in patients with atherosclerotic carotid stenosis is higher than that of the right. Patients with high bifurcation of carotid artery are more likely to be complicated with carotid distortion. Preoperative color doppler ultrasound combined with DSA can evaluate the distortion of extracranial carotid artery, thereby providing reference for the selection of surgical methods.