To investigate the incidence of residual stenosis and its influencing factors after subclavian artery stent placement using color Doppler flow imaging (CDFI).

A total of 201 consecutive patients (204 stents) with severe subclavian artery stenosis (≥70%) or occlusion who underwent subclavian artery stent (SAS) in our hospital from May 2015 to April 2018 were enrolled. All patients were examined by CDFI within one month before and after surgery. According to the results of digital subtraction angiography (DSA) and CDFI detected, the stenosis≥20% after the SAS is defined as in-stent residual stenosis (ISRS). All of 204 stents were divided into ISRS group (67, 32.8%) and non ISRS group (137, 67.2%). The characteristics of SA, type and length of stent were analyzed and compared.

The both groups had no significant differences in age, gender, atherosclerosis risk factors such as diabetes, hyperlipidemia, coronary heart disease, smoking, etc. (P>0.05), but the proportion of hypertension in the ISRS group was higher relatively (68.7% and 48.5%, P=0.007). The area of intra-plaque calcification ≥1/2 was also much more larger than that in non-ISRS group (34.3% vs 9.5%) (P=0.000). There was no significant difference between the length of stenosis and the original diameter of the lesion (P>0.05). The type of stent in ISRS group was mainly self-expanding stent (P=0.000), and the original length of stent was longer than that in non-ISRS group (P=0.011), while the original inner diameter of the stent was no significant difference between the two groups (P=0.454). Multivariate Logistic regression analysis showed that the degree of the plaque calcification (OR=7.205, 95%CI: 3.175-16.348, P=0.000), and stent type (OR=8.591, 95%CI: 2.825-26.131, P=0.000) were independent risk factors for residual stenosis after SAS.

Ultrasound can accurately evaluate the effect of subclavian artery stent placement, detect residual stenosis in time. Preoperative calcification area and stent type are the main factors affecting residual stenosis.