Impact of Drug Release Kinetics on Vascular Response to Different Zotarolimus-Eluting Stents Implanted in Patients With Long Coronary Stenoses

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Examination of the In Vivo Mechanisms of Late Drug-Eluting Stent Thrombosis

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Strut Coverage and Vessel Wall Response to Zotarolimus-Eluting and Bare-Metal Stents Implanted in Patients With ST-Segment Elevation Myocardial Infarction The OCTAMI (Optical Coherence Tomography in Acute Myocardial Infarction) Study

ObjectivesUsing optical coherence tomography, we assessed the proportion of uncovered struts at 6-month follow-up in zotarolimus-eluting stents (ZES), specifically Endeavor (Medtronic CardioVascular, Santa Rosa, California) stents, and identical bare-metal stents (BMS) implanted in patients with ST-segment elevation myocardial infarction (STEMI).BackgroundSirolimus- and paclitaxel-eluting stents implanted in STEMI have been associated with delayed healing and incomplete strut coverage. ZES are associated with a more complete and uniform strut coverage in stable patients, but whether this holds true also after STEMI is unknown.MethodsForty-four patients with STEMI who underwent primary PCI were randomized to ZES or BMS (3:1 randomization). Angiographic, intravascular ultrasound, and optical coherence tomography follow-up was conducted at 6 months and clinical follow-up at 1 year. All images were analyzed by an independent core laboratory that was blind to stent assignments.ResultsThere were no differences between ZES and BMS in percentage of uncovered struts (median: 0.00% [interquartile range (IQR): 0.00% to 1.78%] vs. 1.98% [IQR: 0.21% to 7.33%], p = 0.13), maximum length of uncovered segments (0.00 [IQR: 0.00 to 1.19] mm vs. 1.38 [IQR: 0.65 to 3.30] mm, p = 0.10), percentage of malapposed struts (0.00% [IQR: 0.00% to 0.23%] vs. 0.15% [IQR: 0.00% to 5.81%], p = 0.16), and maximum length of malapposed segments (0.00 [IQR: 0.00 to 0.67] mm vs. 0.33 [IQR: 0.00 to 2.55] mm, p = 0.20). Neointimal response was similar between ZES and BMS (332 [IQR: 240 to 429] μm vs. 186 [IQR: 136 to 348] μm, p = 0.99) and evenly distributed. No late acquired malapposition was observed in both groups. There were no deaths, myocardial infarction, or stent thromboses at 1 year.ConclusionsThis optical coherence tomography study found no difference in strut coverage and similar vessel response to ZES, when compared with identical BMS, implanted during primary percutaneous coronary intervention in STEMI patients. (Six-Month Coverage and Vessel Wall Response of the Zotarolimus Drug-Eluting Stent Implanted in AMI Assessed by Optical Coherence Tomography [OCTAMI]; NCT00704561

Optical Coherence Tomography Assessment of In Vivo Vascular Response After Implantation of Overlapping Bare-Metal and Drug-Eluting Stents

Objectives We designed a randomized trial exploiting optical coherence tomography (OCT) to assess coverage and apposition of overlapping bare-metal stents (BMS) and drug-eluting stents (DES) in human coronary arteries. Background Overlapping DES impair healing in animals. Optical coherence tomography allows accurate in vivo assessment of stent strut coverage and apposition. Methods Seventy-seven patients with long coronary stenoses were randomized to overlapping sirolimus-eluting stents (SES), paclitaxel-eluting stents (PES), zotarolimus-eluting stents (ZES), or BMS. The primary goal of the study was to determine the rate of uncovered/malapposed strut; in overlap versus nonoverlap segments, according to stent type, at 6-month follow-up with OCT. Results A total of 53,047 struts were analyzed. The rate of uncovered/malapposed struts was 1.5 +/- 3.4% and 0.6 +/- 2.7% in overlap versus nonoverlap BMS (p = NS), respectively, and 4.3 +/- 11% and 3.6 +/- 8% in overlap versus nonoverlap DES (p = NS), respectively. There were no differences in the rates of uncovered/malapposed struts between overlapping BMS and DES, likely due to law frequency of uncovered/malapposed struts in ZES (0.1 +/- 0.4%), which offset the higher rates observed in SES (6.7 +/- 9.6%) and PES (6.7 +/- 16.5%, p < 0.05). Overlap segments showed greater neointimal volume obstruction versus nonoverlap segments in all DES (p < 0.05 for all DES types). Strut-level neointimal thickness at overlap and nonoverlap segments were lowest in SES (0.16 +/- 0.1 mm and 0.12 +/- 0.1 mm, respectively) compared with PES (0.27 +/- 0.1 mm and 0.20 +/- 0.1 mm, respectively), ZES (0.40 +/- 0.16 mm and 0.33 +/- 0.13 mm, respectively), and BMS (0.55 +/- 0.31 mm and 0.53 +/- 0.25 mm, respectively, p < 0.05). Conclusions As assessed by OCT the impact of DES on vascular healing was similar at overlapping and nonoverlapping sites. However, strut malapposition, coverage pattern, and neointimal hyperplasia differ significantly according to DES type. (Optical Coherence Tomography for Drug Eluting Stent Safety [ODESSA]; NCT00693030) (J Am Coll Cardiol Intv 2010;3:531-9) (C) 2010 by the American College of Cardiology Foundatio

Strut Coverage and Late Malapposition With Paclitaxel-Eluting Stents Compared With Bare Metal Stents in Acute Myocardial Infarction

Background— The safety of drug-eluting stents in ST-segment elevation myocardial infarction (STEMI) continues to be debated. Pathological studies have demonstrated an association between uncovered struts and subsequent stent thrombosis. Optical coherence tomography can detect stent strut coverage in vivo on a micron-scale level. We therefore used optical coherence tomography to examine strut coverage in patients with STEMI treated with paclitaxel-eluting stents (PES) and bare metal stents (BMS). Methods and Results— In the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial, patients with STEMI were randomized 3:1 to PES or BMS implantation. In a formal substudy, optical coherence tomography at 13 months was performed in 118 consecutive randomized patients (89 PES, 29 BMS) in whom 188 stents were assessed (146 PES and 42 BMS). A total of 44 139 stent struts were analyzed by an independent core laboratory blinded to stent assignment. The primary prespecified end point, the percentage of uncovered stent struts per lesion at follow-up, was 1.1±2.5% in BMS lesions versus 5.7±7.0% in PES lesions ( P <0.0001). Malapposed struts were observed in 0.1±0.2% of BMS lesions versus 0.9±2.1% of PES lesions ( P =0.0003). Percentage net volume obstruction was 36.0±15.4% with BMS and 19.2±11.3% with PES ( P <0.0001). Conclusions— In patients with STEMI undergoing primary percutaneous coronary intervention, implantation of PES as compared with BMS significantly reduces neointimal hyperplasia but results in higher rates of uncovered and malapposed stent struts as assessed by optical coherence tomography at 13-month follow-up. Further studies are required to determine the clinical significance of these findings. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00433966