This study consisted of a randomized controlled trial group and a long balloon observation group.~In the randomized control group, 280 subjects with in-stent restenosis were planned to be recruited and randomly assigned to the test group and the control group in a 1:1 ratio; 30 consecutive subjects will be enrolled in the long balloon observation group, using graceful molimus release coronary balloon catheter with length of 45mm; All 310 subjects were followed up at baseline, surgery, discharge, 1 month after surgery, 6 months after surgery, 9 months after surgery, 1, 2 and 3 years after surgery, and angiography was performed at 9 months after surgery.~The primary endpoint was late lumen loss at 9 months.~The study will enroll 310 subjects. The sample size determination process is as follows:~Randomized controlled trial group:~A prospective, multicenter, randomized, controlled, non-inferior clinical trial design was used with the primary endpoint of intrasegonal LLL at 9 months postoperatively. Sample size was calculated according to the following assumptions:~1) According to previous clinical studies, the LLL of the segment 9 months after paclitaxel release coronary catheter (Sequent Please) was 0.46±0.48mm[1] and 0.46±0.51mm[2]. 2) In this study, it was estimated that the mean LLL in the lesion segment of the experimental group and the control group 9 months after surgery was 0.46mm, and the standard deviation was 0.50mm. 3) The clinically acceptable non-infertility threshold was 0.195mm. When the significance level of the statistical test was set as one-sided 2.5% and the assurance level was set as 80%, they were randomly divided into groups at a ratio of 1:1. 4) Considering the abscission rate of 25% (at the same time considering the early withdrawal from the group caused by other reasons and the random setting), 280 patients were finally enrolled, including 140 in the experimental group and 140 in the control group.~Long balloon observation group:~Because the maximum length of Sequent ® Please Neo in the control group was 40mm, subjects suitable for 45mm long balloon could not be randomly enrolled in the randomized controlled trial group. Therefore, this observation group was selected with a sample size of 30 cases.
This study consisted of a randomized controlled trial group and a long balloon observation group.~In the randomized control group, 280 subjects with in-stent restenosis were planned to be recruited and randomly assigned to the test group and the control group in a 1:1 ratio; 30 consecutive subjects will be enrolled in the long balloon observation group, using graceful molimus release coronary balloon catheter with length of 45mm; All 310 subjects were followed up at baseline, surgery, discharge, 1 month after surgery, 6 months after surgery, 9 months after surgery, 1, 2 and 3 years after surgery, and angiography was performed at 9 months after surgery.