| Part 1 Evaluation by optical coherence tomography of different types of drug-eluting stents in patients with acute coronary syndrome or stable angina pectorisObjective: It has been known that acute coronary syndrome (ACS) is an independent predict factor for late stent thrombosis ,the reason might be related to the impaired vascular healing after drug-eluting stent (DES) due to the disrupted plaque and intracoronary thrombus. Optical coherence tomography (OCT) has provided new opportunities to evaluate vascular response to DES with higher resolution compared to intravascular ultrasound(IVUS) Therefore, we investigated the vascular response after various DES implantations between ACS and stable angina pectoris (SAP) using OCT.Methods: OCT was analyzed at 9-month after DES implantation in 91 ACS patients [49 ACS: 20 sirolimus-eluting stent( SES,Cypher), 12 paclitaxel-eluting stent( PES,Taxus) and 17 zotarolimus-eluting stent (ZES, Endeavor) and 42 SAP: 15 SES, 12 PES and 15 ZES] .Neointimal coverage and malapposition were evaluated in 21,939 struts in 2269-mm single-stented segments.Results: In the ACS group, the incidence of uncovered and malapposed stent struts was significantly higher (8.9±13.7 vs 2.9±6.2 %, p=0.01 and 2.2±5.6 vs 0.5±2.0 %, p=0.02). Among three types of DESs tested, SES showed a significantly higher rate of uncovered struts in the ACS group (17.3±13.4 vs 4.4±6.2 %, p=0.003). PES had a trend toward higher rate of uncovered and malapposed struts in the ACS groups (6.7±7.6 vs 4.0±9.0 %, p=0.13) while ZES had a similar outcome in both groups.Conclusions: neointimal coverage and stent struts apposition at 9-month after DES implantation were different between ACS and SAP, and also variable among the 3-types of DES between ACS and SAP groups. Therefore, the present study suggests that vascular response after DES implantation might be influenced by both clinical presentation and type of DES. Part 2 Evaluation by Optical Coherence Tomography of Vascular Healing after Drug-Eluting Stents Implantation in Acute Myocardial InfarctionObjective: Optical coherence tomography (OCT) has provided new opportunities to evaluate vascular response to drug-eluting stent (DES) with higher resolution compared to intravascular ultrasound(IVUS). This study was designed to compare neointimal coverage and stent malapposition after DESs implantation in patients with acute myocardial infarction using OCT.Methods: OCT was analyzed at 9-month after DESs implantation in 49 AMI patients [20 sirolimus-eluting stent (SES, Cypher), 12 paclitaxel-eluting stent (PES, Taxus) and 17 zotarolimus-eluting stent (ZES, Endeavor )]. Neointimal thickness and strut apposition were measured at each stent strut and every 1 mm corss section. Presence of thrombus was observed in each stent.Results: In total, 12378 stent struts were analyzed. SES had the least neointimal thickness (SES 77±60 um vs PES 153±82 um vs ZES 265±130 um, p<0.01)and % neointimal hyperplasia area(SES 10±8 vs PES 19±8 vs ZES 28±9, p< 0.01), while percentage of uncovered struts were higher in SES and PES than in ZES (SES 15.1±16 vs PES 7.1±10 vs ZES 0.6±1.5, p <0.01 ), and malapposed struts were also significantly more in SES and PES than in ZES[ SES (3.8±7.2)% vs. PES (2.1±4.4)% vs ZES (0±0)%, p<0.01 ]. Higher prevalence of throumbus was found in SES and PES than in ZES (SES 34% vs PES 33% vs ZES 6%, p<0.05).Conclusions: The rate of stent strut coverage and malapposition were significantly different among the DES types in acute myocardial infarction, therefore the type of DES might affect the vascular healing patterns in thrombotic lesions of acute myocardial infarction. Part 3 The Prevalence and Determinant Factors of Intracoronary Thrombus Formation After Drug-Eluting Stents Implantation: Optical Coherence Tomography StudyObjective: Up to now, there was no data about intrathrombus formation by optical coherence tomography (OCT) detection after drug-eluting stents(DESs) implantation. Therefore, we investigated the prevalence and determinant factors of intracoronary thrombus after various DES implantations using OCT.Meathods: 226 patients [244 drug-eluting stents: 95 sirolimus-eluting stent (SES), 62 paclitaxel-eluting stent(PES) and 87 zotarolimus-eluting stent (ZES)] underwent OCT examination at mean 11 months (3-66 months) after DES implantation. We compared baseline characteristics and angiographic and OCT findings according to the presence of thrombus detected by OCT. OCT evaluation focused on neointimal coverage and malapposition at each strut.Results: The intracoronary thrombus was detected in 35 cases [total 14%, 27 SES (28%), 7 PES (11%) and 1 ZES (1 %)] and was more frequently found in longer stent, smaller stent diameter and stent at bifurcation lesions. More uncovered struts (26±23 vs. 8±17, p<0.001) and malapposed struts (6±14 vs. 2±6, p<0.001) were also related to the presence of intracoronary thrombus, which were similar in both SES and PES, respectively. In multivariate logistic regresion analysis, longer stent≥28 mm (odds ratio [OR]: 7.31, CI: 1.79-29.86, p=0.01), stent diameter < 3.0 mm (OR: 4.38, CI: 1.38-13.97, p=0.01) and≥8 uncovered struts (OR: 3.29, CI: 1.07-10.17, p=0.04) were independently predict factor with intracoronary thrombus.Conclusion: The incidence of intracoronary thrombus detected by OCT was 14% after DES implantation, stent length, size and stent strut coverage were determinant factors of intracoronary thrombus after DES implantations.
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