Repeat PCI with BMS or DES is not appropriate if the patient is not able to comply with and tolerate DAPT. 6.3.2. Restenosis After Balloon Angioplasty For clinical restenosis after balloon angioplasty, stent implan- tation is superior to repeat balloon angioplasty or atheroab- lation devices. The REST (REstenosis STent) study showed that target-lesion revascularization rates were 10% for stent- treated patients and 27% for balloon-treated patients 6.3.3. Restenosis After BMS In-stent restenosis is classified according to these angio- graphic characteristics: Pattern I includes focal lesions 10 mm in length; Pattern II is in-stent restenosis 10 mm within the stent; Pattern III includes in-stent restenosis 10 mm extending outside the stent; and Pattern IV is totally occluded in-stent restenosis.847 Treatment of in-stent resteno- sis with balloon angioplasty, repeat BMS, or atheroablation devices for Patterns I to IV resulted in 1-year target-lesion tively. For clinical restenosis after BMS, repeat stenting with DES is preferred. Studies have demonstrated lower recurrent restenosis rates with DES compared with BMS or vascular 6.3.4. Restenosis After DES Clinical restenosis after placement of DES is becoming increasingly common due to the large numbers of patients who have been treated with DES. The predominant angio- graphic pattern for DES in-stent restenosis is focal ( 10 mm in length). Several biologic, mechanical, and technical factors may contribute to DES in-stent restenosis, including drug resistance, hypersensitivity, stent underexpansion, stent strut fracture, nonuniform stent strut coverage, gap in stent cover- age, and residual uncovered atherosclerotic lesion. IVUS might be considered to determine the cause for in-stent restenosis and help guide treatment strategy. 