Comparison of zotarolimus-eluting and everolimus-eluting coronary stents.

BACKGROUND: New-generation coronary stents that release zotarolimus or everolimus have been shown to reduce the risk of restenosis. However, it is unclear whether there are differences in efficacy and safety between the two types of stents on the basis of prospectively adjudicated end points endorsed by the Food and Drug Administration. METHODS: In this multicenter, noninferiority trial with minimal exclusion criteria, we randomly assigned 2292 patients to undergo treatment with coronary stents releasing either zotarolimus or everolimus. Twenty percent of patients were randomly selected for repeat angiography at 13 months. The primary end point was target-lesion failure, defined as a composite of death from cardiac causes, any myocardial infarction (not clearly attributable to a nontarget vessel), or clinically indicated target-lesion revascularization within 12 months. The secondary angiographic end point was the extent of in-stent stenosis at 13 months. RESULTS: At least one off-label criterion for stent placement was present in 66% of patients. The zotarolimus-eluting stent was noninferior to the everolimus-eluting stent with respect to the primary end point, which occurred in 8.2% and 8.3% of patients, respectively (P<0.001 for noninferiority). There were no significant between-group differences in the rate of death from cardiac causes, any myocardial infarction, or revascularization. The rate of stent thrombosis was 2.3% in the zotarolimus-stent group and 1.5% in the everolimus-stent group (P=0.17). The zotarolimus-eluting stent was also noninferior regarding the degree (+/-SD) of in-stent stenosis (21.65+/-14.42% for zotarolimus vs. 19.76+/-14.64% for everolimus, P=0.04 for noninferiority). In-stent late lumen loss was 0.27+/-0.43 mm in the zotarolimus-stent group versus 0.19+/-0.40 mm in the everolimus-stent group (P=0.08). There were no significant between-group differences in the rate of adverse events. CONCLUSIONS: At 13 months, the new-generation zotarolimus-eluting stent was found to be noninferior to the everolimus-eluting stent in a population of patients who had minimal exclusion criteria. (ClinicalTrials.gov number, NCT00617084.)

Delayed coverage in malapposed and side-branch struts with respect to well-apposed struts in drug-eluting stents: in vivo assessment with optical coherence tomography.

BACKGROUND: Pathology studies on fatal cases of very late stent thrombosis have described incomplete neointimal coverage as common substrate, in some cases appearing at side-branch struts. Intravascular ultrasound studies have described the association between incomplete stent apposition (ISA) and stent thrombosis, but the mechanism explaining this association remains unclear. Whether the neointimal coverage of nonapposed side-branch and ISA struts is delayed with respect to well-apposed struts is unknown. METHODS AND RESULTS: Optical coherence tomography studies from 178 stents implanted in 99 patients from 2 randomized trials were analyzed at 9 to 13 months of follow-up. The sample included 38 sirolimus-eluting, 33 biolimus-eluting, 57 everolimus-eluting, and 50 zotarolimus-eluting stents. Optical coherence tomography coverage of nonapposed side-branch and ISA struts was compared with well-apposed struts of the same stent by statistical pooled analysis with a random-effects model. A total of 34 120 struts were analyzed. The risk ratio of delayed coverage was 9.00 (95% confidence interval, 6.58 to 12.32) for nonapposed side-branch versus well-apposed struts, 9.10 (95% confidence interval, 7.34 to 11.28) for ISA versus well-apposed struts, and 1.73 (95% confidence interval, 1.34 to 2.23) for ISA versus nonapposed side-branch struts. Heterogeneity of the effect was observed in the comparison of ISA versus well-apposed struts (H=1.27; I(2)=38.40) but not in the other comparisons. CONCLUSIONS: Coverage of ISA and nonapposed side-branch struts is delayed with respect to well-apposed struts in drug-eluting stents, as assessed by optical coherence tomography. Clinical Trial Registration- http://www.clinicaltrials.gov. Unique identifier: NCT00389220, NCT00617084.

Agreement and reproducibility of gray-scale intravascular ultrasound and optical coherence tomography for the analysis of the bioresorbable vascular scaffold.

OBJECTIVE: To report the agreement between gray-scale intravascular ultrasound (GS-IVUS) and optical coherence tomography (OCT) in assessing the bioresorbable vascular scaffolds (BVS) structures and their respective reproducibility. BACKGROUND: BVS are composed of an erodible polymer. Ultrasound and light signals backscattered from polymeric material differs from metallic stents using GS-IVUS and OCT. METHODS: Forty-five patients included in the ABSORB trial were treated with a 3.0 × 18 mm BVS and imaged with GS-IVUS 20 MHz and OCT post-implantation. Qualitative (ISA, side-branch struts, protrusion, and dissections) and quantitative (number of struts, lumen, and scaffold area) measurements were assessed by two investigators. The agreement and the inter- and intraobserver reproducibility were investigated using the kappa (κ) and the interclass correlation coefficient (ICC). RESULTS: GS-IVUS and OCT agreement was predominantly poor at a lesion, frame, and strut level analysis (κ and ICC <0.4) for qualitative measurements. GS-IVUS demonstrated a reduced ability to detect cross-sections with ISA (4.5% vs. 20.6%), side-branch (SB) struts (6.3% vs. 7.8%), protrusions (3.2% vs. 9.6%), and dissections (0.2% vs. 9.0%) compared with OCT. GS-IVUS reproducibility was poor-moderate (κ and ICC <0.6) except for ISA and SB-struts (κ and ICC between 0.2 and 0.75). OCT showed an excellent reproducibility (κ and ICC > 0.75) except for the assessment of tissue protrusion (κ and ICC between 0.47 and 0.94). GS-IVUS reproducibility was poor-moderate (ICC ≤ 0.5) in assessing the number of struts but excellent with OCT (ICC > 0.85). The reproducibility to assess lumen and scaffold areas was excellent using both techniques (ICC > 0.85). CONCLUSIONS: GS-IVUS has a poor capacity to detect qualitative findings post-BVS implantation and its reproducibility is low compared with OCT. The use of GS-IVUS should be limited when assessing lumen and scaffold areas.

Vascular tissue reaction to acute malapposition in human coronary arteries: sequential assessment with optical coherence tomography.

BACKGROUND: The vascular tissue reaction to acute incomplete stent apposition (ISA) is not well known. The aim of this study was to characterize the vascular response to acute ISA in vivo and to look for predictors of incomplete healing. METHODS AND RESULTS: Optical coherence tomography studies of 66 stents of different designs, implanted in 43 patients enrolled in 3 randomized trials, were analyzed sequentially after implantation and at 6 to 13 months. Seventy-eight segments with acute ISA were identified in 36 of the patients and matched with the follow-up study by use of fiduciary landmarks. The morphological pattern of healing in the ISA segments was categorized as homogeneous, layered, crenellated, bridged, partially bridged, or bare, depending on the persistence of ISA and on the coverage. After 6 months, acute ISA volume decreased significantly, and 71.5% of the ISA segments were completely integrated into the vessel wall. Segments with acute ISA had higher risk of delayed coverage than well-apposed segments (relative risk 2.37, 95% confidence interval 2.01-2.78). Acute ISA size (estimated as ISA volume or maximum ISA distance per strut) was an independent predictor of ISA persistence and of delayed healing at follow-up. CONCLUSIONS: Neointimal healing tends to reduce ISA, with the malapposed stent struts often integrated completely into the vessel wall, resulting in characteristic morphological patterns. Coverage of ISA segments is delayed with respect to well-apposed segments. The larger the acute ISA, the greater the likelihood of persistent malapposition at follow-up and delayed healing.

The impact of patient and lesion complexity on clinical and angiographic outcomes after revascularization with zotarolimus- and everolimus-eluting stents: a substudy of the RESOLUTE All Comers Trial (a randomized comparison of a zotarolimus-eluting stent with an everolimus-eluting stent for percutaneous coronary intervention).

OBJECTIVES: The aim of this study was to investigate the impact of patient and lesion complexity on outcomes with newer-generation zotarolimus-eluting stents (ZES) and everolimus-eluting stents (EES). BACKGROUND: Clinical and angiographic outcomes of newer-generation stents have not been described among complex patients. METHODS: Patients enrolled in the RESOLUTE All Comers trial (A Randomized Comparison of a Zotarolimus-Eluting Stent With an Everolimus-Eluting Stent for Percutaneous Coronary Intervention) were stratified into "complex" and "simple." RESULTS: Of 2,292 patients, 1,520 (66.3%) were complex and treated with ZES (n = 764) or EES (n = 756). Event rates were higher among complex patients, and results did not differ between ZES and EES, regardless of complexity. At 1 year, target lesion failure was 8.9% in ZES- and 9.7% in EES-treated complex patients (p = 0.66) and 6.8% in ZES- and 5.7% in EES-treated simple patients (p = 0.55). Rates of cardiac death (1.3% vs. 2.2%, p = 0.24), target-vessel myocardial infarction (4.3% vs. 4.4%, p = 0.90), and clinically indicated target lesion revascularization (4.4% vs. 4.0%, p = 0.80) were similar for both stent types among complex patients. Definite or probable stent thrombosis occurred in 20 (1.3%) complex patients with no difference between ZES (1.7%) and EES (0.9%, p = 0.26). Angiographic follow-up showed similar results for ZES and EES in terms of in-stent percentage diameter stenosis (22.2 ± 15.4% vs. 21.4 ± 15.8%, p = 0.67) and in-segment binary restenosis (6.6% vs. 8.0%, p = 0.82) in the complex group. CONCLUSIONS: In this all-comers randomized trial, major adverse cardiovascular events were more frequent among complex than simple patients. The newer-generation ZES and EES proved to be safe and effective, regardless of complexity, with similar clinical and angiographic outcomes for both stent types through 1 year. (RESOLUTE-III All Comers Trial: A Randomized Comparison of a Zotarolimus-Eluting Stent With an Everolimus-Eluting Stent for Percutaneous Coronary Intervention; NCT00617084).

Reproducibility of quantitative optical coherence tomography for stent analysis.

AIMS: To assess the inter- and intra- observer reproducibility for strut count, strut apposition and strut tissue coverage measurements with optical coherence tomography (OCT). METHODS AND RESULTS: Ten drug-eluting stents (244 frames, 1712 struts) imaged with OCT nine months after implantation were analysed by two independent analysts. One of the analysts repeated the analysis of five stents (120 frames, 795 struts) one week later. Offline analysis was performed with the proprietary LightLab Imaging software. The number of struts was counted and lumen and stent area contours were traced. Tissue coverage thickness was measured at 360 degrees of vessel circumference and in front of every individual strut. The number of malapposed struts was determined. There was good agreement for strut number count (Kendall's Tau-b 0.90 for inter- and 0.94 for intra- observer variability). The relative difference for lumen area, stent area and tissue coverage measurements was around 1%. There was complete inter- and intra- observer agreement for malapposed struts classification (4 out of 1708 struts, Kappa=1). CONCLUSIONS: In a Corelab setting, the inter- and intra- observer reproducibility for strut count, strut apposition and strut tissue coverage measurements with OCT is excellent. This emphasises the value of OCT as a tool for the clinical long-term assessment of stents.