Macrophage behaviour 72 hours after implantation of biodegradable polymer-based sirolimus-eluting stent in a case of ST elevation myocardial infarction.

While the vascular healing process after drug-eluting stent implantation is not fully elucidated, it is generally accepted that macrophages play an important role in inflammation. It is also known that macrophages involved in the pathogenesis of atherosclerosis may stem from several origins, that is, monocyte-derived macrophages versus resident macrophages. However, little is known about the role of human macrophages on reperfusion of culprit coronary arteries in patients with atherosclerotic disease who have sustained acute coronary syndrome. In this present case report, we describe the presence of cluster of differentiation (CD) 163-positive macrophages in close proximity to the stent struts at the luminal site 72 hours after drug-eluting stent implantation in the culprit coronary lesion for ST elevation myocardial infarction by postmortem examination.

Short- and mid-term intravascular ultrasound analysis of the new zotarolimus-eluting stent with durable polymer ­ results from the RESOLUTE trial ­.

BACKGROUND: The Resolute stent is a newly developed system with a bio-histocompatible polymer that allows programmed drug delivery up to 180 days. The aim of this intravascular ultrasound (IVUS) analysis was to evaluate the short- (4 months) and mid-term (9 months) efficacy using the Resolute stent. METHODS AND RESULTS: Data were derived from the RESOLUTE trial, a prospective, multicenter, non-randomized, single-arm study to treat de novo native coronary artery lesions. This trial included 2 cohorts with different follow-up periods, and all enrollment patients in this trial received IVUS study. Follow-up IVUS was available in 24 patients (4-month group) and 88 patients (9-month group). Neointimal obstruction (%) was defined as neointimal volume divided by stent volume. Cross-sectional narrowing (CSN, %) was defined as neointimal area divided by stent area. No significant differences in vessel, lumen and stent volume at post-procedure were observed within stented segments between the 4- and 9-month follow-up groups. Although neointimal volume and % neointimal obstruction showed no significant difference between the 2 groups (% neointimal obstruction: 2.2 ± 2.5 vs 3.7 ± 4.0%, P=0.09), maximum CSN was significantly larger in the 9-month group. There were 7 cases of late incomplete stent apposition. CONCLUSIONS: These IVUS results showed minimum growth of neointimal proliferation by the Resolute stent throughout the stented segment up to 9 months follow up.

Impact of intravascular ultrasound lesion characteristics on neointimal hyperplasia following sirolimus-eluting stent implantation.

The effect of lesion characteristics on neointimal hyperplasia after sirolimus-eluting stent implantation was examined in 45 patients who underwent successful preinterventional intravascular ultrasound. There were no differences in neointimal hyperplasia between the moderate/severe calcified lesion group (calcium arc >120 degrees ) and the non/mild calcified lesion group or between the positive vessel remodeling group (external elastic membrane area at the minimal lumen area site larger than that at the proximal reference site) and negative vessel remodeling group. No correlation between preinterventional plaque burden and neointimal hyperplasia was found. In patients who have coronary artery disease, sirolimus-eluting stents continue to demonstrate striking suppression of neointimal proliferation, irrespective of lesion characteristics previously associated with greater restenotic risk.

Intravascular ultrasound insights from the Cobalt Chromium Stent With Antiproliferative for Restenosis II (COSTAR II) trial comparing CoStar and Taxus paclitaxel-eluting stents.

BACKGROUND: Dedicated IVUS analyses of the second CObalt chromium STent with Antiproliferative for Restenosis (COSTAR II) trial have not been documented. We aim to compare IVUS findings between CoStar paclitaxel-eluting stent (PES) and Taxus PES in patients enrolled in the COSTAR II trial. We also attempted to examine the possible regional impact of multiple stenting. METHODS AND MATERIALS: Among the 1700 patients enrolled, 238 were assigned to an IVUS cohort including 168 patients treated by provisional multiple stenting. At 9 months, qualitative and quantitative IVUS observations including incomplete stent apposition (ISA) and neointimal proliferation (neointimal obstruction: neointimal volume/stent volume ×100) were compared between CoStar and Taxus PESs. RESULTS: In qualitative analysis, late-acquired ISA was observed in 1 patient treated by Taxus PES. Impaired strut continuity suggestive of stent fracture was observed in 2 out of 33 patients treated by multiple CoStar, and 4 out of 21 patients treated by multiple Taxus (P=.14). No such findings were found in single-stented patients in either stent subset. Quantitative analysis showed greater neointimal obstruction in CoStar (19.7%±13.4%, n=52) than in Taxus (10.7%±9.9%, n=38), whereas no significant difference in neointimal obstruction was found between single and multiple stenting in either CoStar or Taxus PES. CONCLUSIONS: The CoStar PES exhibits greater neointimal proliferation compared with Taxus PES at 9 months but with similar qualitative outcomes including late-acquired ISA. IVUS findings suggestive of stent fracture were found only in multiple-stenting cases irrespective of the stent used.

Impact of polymer formulations on neointimal proliferation after zotarolimus-eluting stent with different polymers: insights from the RESOLUTE trial.

BACKGROUND: Polymer formulation may affect the efficacy of drug-eluting stents. Resolute, Endeavor, and ZoMaxx are zotarolimus-eluting stents with different stent platforms and different polymer coatings and have been tested in clinical trials. The aim of this analysis was to compare the efficacy of zotarolimus-eluting stents with different polymers. METHODS AND RESULTS: Data were obtained from the first-in man trial or first randomized trials of each stent, The Clinical RESpOnse EvaLUation of the MedTronic Endeavor CR ABT-578 Eluting Coronary Stent System in De Novo Native Coronary Artery Lesions (RESOLUTE), Randomized Controlled Trial to Evaluate the Safety and Efficacy of the Medtronic AVE ABT-578 Eluting Driver Coronary Stent in De Novo Native Coronary Artery Lesions (ENDEAVOR II), and ZoMaxx I trials. Follow-up intravascular ultrasound analyses (8 to 9 months of follow-up) were possible in 353 patients (Resolute: 88, Endeavor: 98, ZoMaxx: 82, Driver: 85). Volume index (volume/stent length) was obtained for vessel, stent, lumen, peristent plaque, and neointima. Cross-sectional narrowing was defined as neointimal area divided by stent area (%). Neointima-free frame ratio was calculated as the number of frames without intravascular ultrasound-detectable neointima divided by the total number of frames within the stent. At baseline, vessel, lumen, and peristent plaque volume index were not significantly different among the 4 stent groups. At follow-up, percent neointimal obstruction was significantly lower in Resolute compared with Endeavor, ZoMaxx, and Driver (Resolute: 3.7±4.0, Endeavor: 17.5±10.1, ZoMaxx: 14.6±8.1, Driver: 29.4±17.2%; P<0.001). Greater maximum cross-sectional narrowing and higher neointima-free frame ratio, suggesting less neointimal coverage, were observed in Resolute compared with other stent groups. Multiple regression analysis confirmed that the biodurable polymer used in Resolute independently correlated with neointimal suppression among 3 zotarolimus-eluting stents. CONCLUSIONS: The different polymer formulations significantly affect the relative amount of neointima for zotarolimus-eluting stents. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00248079.