Incidence of in-stent restenosis over 13 years - a study based on a national registry

Background: In-stent restenosis (ISR) is one drawback of coronary angioplasty with stent implantation. Purpose: We investigated the incidence of ISR, its clinical presentation and treatment from a national registry. Methods: From all patients (pts) undergoing percutaneous coronary intervention (PCI) from 2002 to 2014, we selected those who had previous history of PCI (n=15326). ISR was defined as diameter stenosis ≥ 50% in stent segment, being selected the interventions in which, at least, 1 IRS lesion was treated (n=3069). They were divided in 3 temporal groups:2002-2003 (group 1, n=179, 5.8%)– bare metal stent era; 2004-2008 (group 2,n=816, 26.6%)– 1st generation stent era; 2009-2014 (group 3, n=2074, 67.6%)– 2nd generation stent era. For each group we compared clinical features and treatment. Results: Over time, it has been observed a reduction in IRS incidence (24.8 vs 23.5 vs 18.6%;p for trend <0.001). Pts from group 3 were older (p=0.01), had higher prevalence of hypertension (63.7 vs 75.6 vs 78.4%;p<0.001), dyslipidemia (61.5 vs 68.5 vs 73.9%;p<0.001) and diabetes (31.3 vs 33.5 vs 38.5%;p=0.012). They also had more frequently history of previous myocardial infarction (p<0.001). Although admissions were more frequently due to stable angina (41% of total) or post non-ST segment myocardial infarction (16.3% of total); it was noticed, over time, an increase in admissions due to ST segment elevation myocardial infarction (1.1 vs 7.4 vs 11.4%;p<0.001) and unstable angina (1.1 vs 1.8 vs 3.7%;p<0.001). Most of pts presented with good systolic ventricular function, but an increase of pts with moderated (2.6 vs 9.0 vs 11.2%;p<0.001) and severe (1.3 vs 1.4 vs 4.7%;p<0.001) systolic dysfunction was observed. From 3069 PCI performed, a total of 3461 IRS lesions were treated. It was observed, at most, 3 IRS lesions for PCI. Over time, the most frequent presentation was 1 lesion for PCI (88.4% of total), being noticed a decreasing in number of multiple IRS lesions (15.1 vs 11.3 vs 9.6%;p=0.035). Incidence of ISR has increased in left descendant coronary artery (34.5 vs 39.8 vs 42.4%;p<0.001) and treatment was more frequently performed in more complex lesions (p<0.001). It was noticed a reduction in treatment with stent (72.7 vs 74.4 vs 52.8%;p<0.001) and an increasing use of only PCI balloon (39.3 vs 57.8 vs 45.8%;p=0.002) and trombectomy (0.0 vs 2.2 vs 8.2%;p<0.001). Conclusion: In spite of increasing in risk profile of pts over time, it was observed a reduction of incidence of ISR and multiple ISR lesions. It also was observed an increasing number of interventions avoiding second stent implantation.