420 patients with DES-ISR will be recruited in this study. After angiography, patients with DES-ISR to be treated with DEB will be randomly assigned to FFR-guided and angiography-guided groups. In FFR group, FFR at maximum hyperemia will be measured after pretreatment of DES-ISR lesion by balloons(non-compliant balloon, cutting balloon or scoring balloon). If FFR <0.9, the operator will dilate the DES-ISR lesion again before another FFR is measured. If FFR>=0.9, DEB will be used and final FFR will be measured at the end of the procedure. In angiography group, the operator will treat the DES-ISR lesion with balloons(non-compliant balloon, cutting balloon or scoring balloon), and then DEB without FFR guidance.
This is a prospective single center, randomized controlled clinical study aimed to compare the clinical and angiographic follow-up results of patients with in-stent restenosis(ISR) after coronary drug eluting stent(DES) implantation treated by fractional flow reserve -guided and angiography guided drug eluting balloon(DEB) intervention. This study intends to confirm the clinical benefits of optimizing DEB intervention of DES-ISR by FFR.