Objective To explore differences in the morphology of atherosclerotic plaques among active smokers, passive smokers, and nonsmokers using CT angiography (CTA).

Methods A retrospective analysis was performed on 284 patients (133 males and 151 females aged 42−79 (60.3±12.5) years old) with suspected cerebrovascular disease, including 95 active smokers and 87 passive smokers, and 102 nonsmokers who underwent 64-slice extracranial CTA in Chiping People's Hospital in Liaocheng City of Shandong Province from January 2017 to July 2019. Numbers of plaque involved segments, plaque type, area, burden, and remodeling index were compared among the three groups. Correlations between smoking index and numbers of plaque involved segments in the smoking and passive smoking groups were also calculated. Rates and the χ² test were used to analyze qualitative data, while t test and one-way ANOVA were used to assess quantitative data. Spearman’s rank correlation test was used to analyze the relationship between smoking index and numbers of plaque involved segments.

Results No difference in age, body mass index, incidence rates of diabetes, hypertension, hyperlipidemia was observed between groups (F=0.30, 0.43; χ²=1.58, 0.19, 0.56, all P>0.05). More males belonged to the active smoking group (83.2%, 79/95) than to the passive smoking (31.0%, 27/87) and nonsmoking (26.5%, 27/102) groups (χ²=10.03, 9.77, both P<0.05). A total of 2840 segments from 284 patients were studied, and 2058 (72.5%) segments revealed plaques. Total plaques (80.5% (765/950), 74.7% (650/870)), noncalcified plaques (46.8% (445/950), 40.0% (348/870)), and mixed plaques (45.6% (433/950), 41.4% (360/870)) involved segments percentages were more higher in the smoking and passive smoking groups than in the nonsmoking group (total plaques, 63.0% (643/1020); noncalcified plaques, 20.9% (213/1020); mixed plaques, 30.8% (314/1020)) (χ²=7.43−21.33, all P<0.05). Total plaques, noncalcified plaques involved segments percentages in the smoking group were more higher than in the passive smoking groups(χ²=7.40, 9.77, both P<0.05). Smokers and passive smokers had a higher plaque area, plaque burden, and remodeling index than nonsmokers in three types of plaques(t=6.54−20.11, all P<0.05), while smokers had a higher plaque area, plaque burden, and remodeling index than passive smokers in noncalcified and mixed plaques (t=9.05−15.64, all P<0.05). A positive correlation between smoking index and total plaques, noncalcified plaques, mixed plaques involved segments numbers in the smoking and passive smoking groups (smoking: r=0.52, 0.57, 0.48, all P<0.05; passive smoking: r=0.40, 0.42, 0.43, all P<0.05) were observed.

Conclusions Active and passive exposure to smoke can lead to more atherosclerotic plaques and higher quantitative index. The greater the amount of smoking and the longer the age, the more segments involved in carotid artery plaque will be found.