Long-term outcomes of percutaneous coronary intervention for in-stent restenosis among Medicare beneficiaries

Background: In-stent restenosis (ISR) is highly prevalent and leads to repeat revascularisation. Long-term implications of ISR are poorly understood. Aims: This study aimed to evaluate the long-term outcomes of patients undergoing percutaneous coronary intervention (PCI) for ISR. Methods: National Cardiovascular Data Registry CathPCI records for individuals aged ≥65 years undergoing PCI from July 2009 to December 2014 were linked to Medicare claims. Baseline characteristics and long-term rates of death, myocardial infarction (MI), repeat revascularisation including target vessel revascularisation (TVR), and major adverse cardiovascular and cerebrovascular events (MACCE) were compared between ISR PCI versus de novo lesion PCI. Results: Of 653,304 individuals, 10.2% underwent ISR PCI and 89.8% underwent de novo lesion PCI. The median duration of follow-up was 825 days (quartile 1: 352 days-quartile 3: 1,379 days). The frequency of MACCE (55.6% vs 45.0%; p<0.001), all-cause mortality (27.8% vs 25.5%; p<0.001), MI (19.0% vs 12.3%; p<0.001), repeat revascularisation (31.9% vs 18.6%; p<0.001), TVR (22.4% vs 8.0%; p<0.001), and stroke (8.8% vs 8.3%; p=0.005) was higher after ISR PCI. After multivariable adjustment, ISR PCI remained associated with worse long-term outcomes than after de novo lesion PCI (hazard ratio [HR] for MACCE 1.24 [95% CI: 1.22, 1.26], mortality 1.07 [95% CI: 1.05, 1.09], MI 1.44 [95% CI: 1.40, 1.48], repeat revascularisation 1.55 [95% CI: 1.51, 1.59], and TVR 2.50 [95% CI: 2.42, 2.58]). Conclusions: ISR PCI was common and was associated with a significantly higher risk of recurrent long-term major ischaemic events compared to patients undergoing de novo lesion PCI. There remains a need for new strategies to minimise ISR.