We randomly assigned 1212 eligible patients to the Tong Xin Luo group (n = 607) and the placebo group (n = 605), all of whom underwent bilateral carotid artery biochemical assessment and ultrasound examination at baseline. The first participant entered the trial in September 2009, enrollment ended in December 2011, and follow-up ended in February 2014. During follow-up, the shedding rate in the Tong Xin Luo and placebo groups was 17.8% (108) and 15.9% (96), respectively. Thus, 1008 participants (499 in the Tong Xin Luo group and 509 in the placebo group) completed the study follow-up (Figure 1).

The demographic and clinical characteristics of the patients are shown in Table 1. In the complete analysis set, the mean ages of the Tong Xin Luo and placebo groups were 61.4 (SD, 8.4) and 61.4 (SD, 8.4) years, respectively, and 60.5% (367/607) and 58.7% (355/605) of the Tong Xin Luo and placebo groups were male, respectively. Conventional western drugs were used in 75.1 percent of patients, of which 36.4 percent in the Tong Xin Luo group and 33.9 percent in the placebo group were prescribed statins. As a result, the two branches are properly balanced on the baseline variables.

At 24 months, the mean IMT in the Tong Xin Luo and placebo groups was 0.952 ± 0.151 mm and 0.970 ± 0.149 mm. Compared with baseline measurements, the mean LS IMT in the Tong Xin Luo group decreased by 0.0001 (95%CI:-0.0049 to 0.0048) at 12 months, while the mean LS IMT in the placebo group increased by 0.0149 (95%CI:0.01 to 0.097) at 12 months. Mean LS IMT decreased by 0.0018 (95%CI:-0.0066 to 0.0031) in the Tong Xin Luo group at 24 months, but increased by 0.0307 (95%CI:0.0259 to 0.0355) in the placebo group (p < 0.001 for interactions, Table 2). The mean annualized changes in IMT in the Tong Xin Luo and placebo groups were -0.000095 mm (95% confidence interval: −0.00330 to −0.00141) and 0.01312 mm (95% confidence interval: 0.01076~0.01548), and there was a significant difference between the two groups, with the difference between the groups being −0.01407