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BackgroundIn the ISAR-CABG (Is Drug-Eluting Stenting Associated with Improved Results in Coronary Artery Bypass Grafts?) trial, clinical outcomes at 1 year were superior in patients randomized to treatment of saphenous vein graft lesions (SVG) with drug-eluting stents (DES) compared with bare metal stents. The aim of this analysis was to compare clinical outcomes between treatment groups at 5-year follow-up.MethodsPatients with symptoms or objective evidence of myocardial ischaemia in the presence of >50% de novo stenosis of saphenous vein grafts undergoing PCI were randomly allocated (1:1) to treatment with DES or bare metal stents. Within the DES group, patients were randomized (1:1:1 allocation) to treatment with one of 3 drug-eluting stent types: early generation paclitaxel-eluting stent or sirolimus-eluting stent or new generation biodegradable polymer sirolimus-eluting stent. The primary endpoint was the combined incidence of death, myocardial infarction, or target lesion revascularization (TLR). Secondary endpoints were the combined incidence of death or myocardial infarction, TLR and definite stent thrombosis.[Figure]Results610 patients were randomized to treatment with DES (n=303) or BMS (n=307). There were no differences in baseline clinical, lesion or procedural characteristics between treatment groups. At 5 years, the primary endpoint occurred in 159 (55·5%) patients in the DES group vs. 157 (53·6%) patients in the bare metal stent group (hazard ratio [HR] HR 0·98, 95% CI 0·79–1·23, P=0·89): death or myocardial infarction in 93 (32·8%) versus 108 (36·6%) patients (HR 0·85, 95% CI 0·64–1·12, P=0·24) and target lesion revascularization in 84 (33·1%) vs. 69 (25.5%) patients (HR 1·20, 95% CI 0·87–1·64, P=0·27) (Figure, Panel A), respectively. The incidence of definite stent thrombosis was in 5 (2·0%) vs. 1 (0·4%) patients in the DES and bare metal stent groups, respectively (5·11 (0·60–44·72), p=0.14). There was an interaction between the treatment effect with time for both the primary endpoint and TLR (Pinteraction=0·004 and <0.001, respectively). Landmark analysis showed that despite significantly lower rates of the primary endpoint and TLR in the DES group compared with the bare metal stent group at one year, between 1 and 5 years, the primary endpoint occurred numerically more frequently in the DES group (HR 1·28, 95% CI 0·97–1·68, P=0·08), driven by a significantly higher rate of TLR (HR 2·07, 95% CI 1·36–3·16, P=0·001) (Figure, Panel B). There was no significant difference in incidence of any endpoint among the 3 groups randomized to treatment with the 3 DES types studied.ConclusionIn patients undergoing treatment of SVG lesions, the clinical advantage of DES over bare metal stents demonstrated at 1 year was not sustained at 5-year follow-up due to higher attrition of efficacy in the DES group.

IntroductionBifurcation stenting has historically been associated with higher rates of adverse clinical events. Optical coherence tomography (OCT) surveillance including grey-scale signal intensity (GSI) analysis provides information on vessel wall healing and can differentiate mature from immature tissue coverage after stent implantation. We sought to evaluate OCT-assessed healing of a novel thin-strut bioresorbable polymer everolimus-eluting stent after 3–6 months post bifurcation stenting.MethodsPatients receiving bifurcation stenting with a planned two-stent approach using a thin-strut bioresorbable polymer everolimus-eluting stent and having an OCT surveillance data collected at 3–6 months post stenting follow-up were included in this study. OCT was performed using commercially-available frequency domain OCT imaging system. Raw data of OCT image acquisitions were collected and sent to a centralized core laboratory. Morphometric analysis of contiguous cross-sections was performed at 1 mm longitudinal intervals within the stented segment (QIvus 3.0.26.0 software). GSI analysis of tissue overlying stent struts was also performed. For each cross-section, the neointimal region of interest (ROI) above each covered stent strut was delineated and 256-level GSI was measured for every pixel within the ROI (Image J software). Tissue coverage was classified as mature or immature according to a standard cut-off values derived from prior published studies (91.6 if strut calibration, 109.7 if guidewire calibration).ResultsData on a total of 31 vessels from 17 treated patients was available at a median of 5 months post stenting. Morphometric analysis revealed the mean length of stented segments to be 27.68 ±16.35 mm. The mean minimum lumen area was 5.97 ±2.97 mm ² while the minimum stent area was 6.67 ±2.63 mm ². Average lumen area was 8.27 ±2.97 mm2while the average stent area was 9.02 ±2.95 mm2. The total number of frames assessed was 869, with a total of 9,975 visible struts. Overall strut coverage was 96.93%, while 0.34% of struts were malapposed. The mean thickness of neointimal coverage was 101.47 ±42.16µm, while the mean neointimal area was 0.75 ±0.49 mm2and the mean percentage stenosis 9.18±7.45%. A total of 28 lesions and 7,971 neo-intimal regions of interest (ROIs) were assessed using GSI analysis. The mean GSI score was 95.11. A total of 53.79% of ROIs were classified as mature. Scatter plot of the GSI scores is depicted in Figure 1, Panel A, while the distribution of immature and mature ROIs is displayed in Figure 1, Panel B.ConclusionsAt 3–6 months after implantation of thin-strut bioresorbable polymer EES in bifurcation lesions using a planned two stent approach, antirestenotic efficacy was high and rates of uncovered and malapposed struts was low. GSI analysis showed that more than half of neointimal areas analysed were classified as mature in keeping with well advanced vessel healing.