Risk of restenosis for in-stent restenosis and de novo lesions treated during the same percutaneous coronary intervention procedure

Background Patients undergoing percutaneous coronary intervention (PCI) for in-stent restenosis (ISR) lesions have been reported to experience worse outcomes than those treated for de novo lesions. However, no study has yet directly compared these two lesion types when treated in the same patient during the same procedure. Purpose To compare the risk of restenosis between ISR and de novo lesions treated during the same PCI procedure. Methods This retrospective, observational, single-centre cohort study included 1,493 patients who underwent PCI for at least one ISR lesion and one de novo lesion during the same procedure at a tertiary cardiac centre, between 2006 and 2015. Patients with cardiogenic shock and lesions located in close proximity were excluded. The primary endpoint was clinical restenosis, as assessed by the need for target lesion revascularisation (TLR), and the secondary endpoint was definite stent thrombosis. Both were evaluated at 1 and 3 years. Results A total of 1,493 patients were included, contributing 3,794 lesions, of which 1,766 were ISR lesions and 2,028 were de novo lesions. Clinical restenosis rates were significantly higher in ISR than in de novo lesions at 1 year (16.1% vs. 10.3%; HR=1.62, 95% CI 1.35–1.94; p <0.001) and 3 years (22.4% vs. 15.3%; HR=1.55, 95% CI 1.33–1.80; p <0.001). However, definite stent thrombosis rates were low and did not differ significantly between ISR and de novo lesions at 1 year (0.3% vs. 0.5%, HR=0.64, 95% CI 0.21–1.90; p = 0.416) or 3 years (0.5% vs. 0.6%; HR=0.76, 95% CI 0.31–1.86; p = 0.548). Conclusions In patients undergoing PCI for both ISR and de novo lesions, ISR lesions were associated with a significantly higher risk of clinical restenosis at 1 and 3 years than de novo lesions, whereas definite stent thrombosis did not differ between lesion types.