Byeong Keuk Kim

A New Strategy for Discontinuation of Dual Antiplatelet Therapy The RESET Trial (REal Safety and Efficacy of 3-month dual antiplatelet Therapy following Endeavor zotarolimus-eluting stent implantation)

OBJECTIVES The goal of this study was to evaluate shorter duration (3 months) dual antiplatelet therapy (DAPT) after drug-eluting stent (DES) implantation. BACKGROUND There have been few published reports of prospective randomized clinical studies comparing the safety and efficacy of shorter duration DAPT after DES implantation. METHODS We randomly assigned 2,117 patients with coronary artery stenosis into 2 groups according to DAPT duration and stent type: 3-month DAPT following Endeavor zotarolimus-eluting stent (E-ZES) implantation (E-ZES+3-month DAPT, n=1,059) versus 12-month DAPT following the other DES implantation (standard therapy, n=1,058). We hypothesized that the E-ZES+3-month DAPT would be noninferior to the standard therapy for the primary composite endpoint (cardiovascular death, myocardial infarction, stent thrombosis, target\vessel revascularization, or bleeding) at 1 year. RESULTS The primary endpoint occurred in 40 (4.7%) patients assigned to E-ZES+3-month DAPT compared with 41 (4.7%) patients assigned to the standard therapy (difference: 0.0%; 95% confidence interval [CI]: -2.5 to 2.5; p=0.84; p<0.001 for noninferiority). The composite rates of any death, myocardial infarction, or stent thrombosis were 0.8% and 1.3%, respectively (difference: -0.5%; 95% CI: -1.5 to 0.5; p=0.48). The rates of stent thrombosis were 0.2% and 0.3%, respectively (difference: -0.1%; 95% CI: -0.5 to 0.3; p=0.65) without its further occurrence after cessation of clopidogrel in the E-ZES+3-month DAPT group. The rates of target vessel revascularization were 3.9% and 3.7%, respectively (difference: 0.2%; 95% CI: -2.3 to 2.6; p=0.70). CONCLUSIONS E-ZES+3-month DAPT was noninferior to the standard therapy with respect to the occurrence of the primary endpoint. (REal Safety and Efficacy of a 3-month dual antiplatelet Therapy following E-ZES implantation [RESET]; NCT01145079).

Mortality in patients treated with extended duration dual antiplatelet therapy after drug-eluting stent implantation: a pairwise and Bayesian network meta-analysis of randomised trials

BACKGROUND Despite recent studies, the optimum duration of dual antiplatelet therapy (DAPT) after coronary drug-eluting stent placement remains uncertain. We performed a meta-analysis with several analytical approaches to investigate mortality and other clinical outcomes with different DAPT strategies. METHODS We searched Medline, Embase, Cochrane databases, and proceedings of international meetings on Nov 20, 2014, for randomised controlled trials comparing different DAPT durations after drug-eluting stent implantation. We extracted study design, inclusion and exclusion criteria, sample characteristics, and clinical outcomes. DAPT duration was categorised in each study as shorter versus longer, and as 6 months or shorter versus 1 year versus longer than 1 year. Analyses were done by both frequentist and Bayesian approaches. FINDINGS We identified ten trials published between Dec 16, 2011, and Nov 16, 2014, including 31,666 randomly assigned patients. By frequentist pairwise meta-analysis, shorter DAPT was associated with significantly lower all-cause mortality compared with longer DAPT (HR 0·82, 95% CI 0·69-0·98; p=0·02; number needed to treat [NNT]=325), with no significant heterogeneity apparent across trials. The reduced mortality with shorter compared with longer DAPT was attributable to lower non-cardiac mortality (0·67, 0·51-0·89; p=0·006; NNT=347), with similar cardiac mortality (0·93, 0·73-1·17; p=0.52). Shorter DAPT was also associated with a lower risk of major bleeding, but a higher risk of myocardial infarction and stent thrombosis. We noted similar results in a Bayesian framework with non-informative priors. By network meta-analysis, patients treated with 6-month or shorter DAPT and 1-year DAPT had higher risk of myocardial infarction and stent thrombosis but lower risk of mortality compared with patients treated with DAPT for longer than 1 year. Patients treated with DAPT for 6 months or shorter had similar rates of mortality, myocardial infarction, and stent thrombosis, but lower rates of major bleeding than did patients treated with 1-year DAPT. INTERPRETATION Although treatment with DAPT beyond 1 year after drug-eluting stent implantation reduces myocardial infarction and stent thrombosis, it is associated with increased mortality because of an increased risk of non-cardiovascular mortality not offset by a reduction in cardiac mortality. FUNDING None.

Short- Versus Long-Term Dual Antiplatelet Therapy After Drug-Eluting Stent Implantation: An Individual Patient Data Pairwise and Network Meta-Analysis

BACKGROUND Randomized controlled trials comparing short- (≤6 months) with long-term (≥1 year) dual antiplatelet therapy (DAPT) after drug-eluting stent(s) (DES) placement have been insufficiently powered to detect significant differences in the risk of major adverse cardiac events (MACE). OBJECTIVES This study sought to compare clinical outcomes between short- (≤6 months) and long-term (1 year) DAPT and among 3 months, 6 months, and 1 year of DAPT post-DES placement by performing an individual patient data pairwise and network meta-analysis. METHODS Randomized controlled trials comparing DAPT durations after DES placement were searched through the MEDLINE, EMBASE, and Cochrane databases and in international meeting proceedings. The primary study outcome was 1-year risk of MACE (cardiac death, myocardial infarction, or definite/probable stent thrombosis). RESULTS Four trials including 8,180 randomized patients were identified. At 1-year follow-up, short-term DAPT was associated with similar rates of MACE (hazard ratio [HR]: 1.11; 95% confidence interval [CI]: 0.86 to 1.43; p = 0.44), but significantly lower rates of bleeding (HR: 0.66; 95% CI: 0.46 to 0.94; p = 0.03) versus prolonged DAPT. Comparable results were apparent in the landmark period between DAPT discontinuation and 1-year follow-up (for MACE: HR: 1.20; 95% CI: 0.77 to 1.89; p = 0.42) (for bleeding: HR: 0.44; 95% CI: 0.21 to 0.91; p = 0.03). There were no significant differences in 1-year rates of MACE among 3-month versus 1-year DAPT, 6-month versus 1-year DAPT, or 3-month versus 6-month DAPT. CONCLUSIONS Compared with prolonged DAPT, short-term DAPT is associated with similar rates of MACE but lower rates of bleeding after DES placement.

Randomized comparison of clinical outcomes between intravascular ultrasound and angiography-guided drug-eluting stent implantation for long coronary artery stenoses

OBJECTIVES This study sought to assess the impact of intravascular ultrasound (IVUS) guidance on clinical outcomes following drug-eluting stent implantation when treating long lesions. BACKGROUND The role of IVUS guidance when treating long lesions has been tested during bare-metal stent, but not during drug-eluting stent, implantation. METHODS A total of 543 patients treated with stents ≥ 28 mm in length were randomly assigned to IVUS guidance (n = 269) versus angiography guidance (n = 274). The primary endpoint was a composite of major adverse cardiac events (MACE), including cardiovascular death, myocardial infarction, target vessel revascularization, or stent thrombosis at 1 year following intervention. RESULTS In the intention-to-treat analysis, total stent length was 32.4 mm in the IVUS-guided arm versus 32.3 mm in angiography-guided arm (p = 0.84). Adjunct post-dilation was more frequently performed in the IVUS-guided arm (54.6% vs. 44.5%, p = 0.03); post-intervention minimal lumen diameters were similar (2.55 vs. 2.55 mm, respectively, p = 0.50); and MACE occurred in 12 (4.5%) patients in IVUS-guided arm and in 20 (7.3%) patients in the angiography-guided arm (p = 0.16). However, among the 269 patients assigned to IVUS guidance, IVUS was not used in 13 patients (4.8%); conversely, in 274 patients assigned to angiography alone, 41 patients (15.0%) were treated with IVUS guidance. Therefore, in a per-protocol analysis according to actual IVUS usage, minimum lumen diameter was larger (2.58 vs. 2.51 mm, p = 0.04), and MACE rates were lower: 4.0% in the IVUS-guided arm versus 8.1% in the angiography-guided arm (p = 0.048). CONCLUSIONS A strategy of routine IVUS for drug-eluting stent implantation in long lesions did not improve the 1-year MACE rates. The IVUS use per operator decision was associated with improved results. (A New Strategy Regarding Discontinuation of Dual Antiplatelet; NCT01145079).

Clinical Impact of Intravascular Ultrasound–Guided Chronic Total Occlusion Intervention With Zotarolimus-Eluting Versus Biolimus-Eluting Stent Implantation Randomized Study

Background—There have been no randomized studies comparing intravascular ultrasound (IVUS)–guided versus conventional angiography–guided chronic total occlusion (CTO) intervention using new-generation drug-eluting stent Therefore, we conducted a prospective, randomized, multicenter trial designed to test the hypothesis that IVUS-guided CTO intervention is superior to angiography-guided intervention. Methods and Results—After successful guidewire crossing, 402 patients with CTOs were randomized to the IVUS-guided group (n=201) or the angiography-guided group (n=201) and secondarily randomized to Resolute zotarolimus-eluting stents or Nobori biolimus-eluting stents. The primary and secondary end points were cardiac death and a major adverse cardiac event defined as the composite of cardiac death, myocardial infarction, or target-vessel revascularization, respectively. After 12-month follow-up, the rate of cardiac death was not significantly different between the IVUS-guided group (0%) and the angiography-guided group (1.0%; P by log-rank test=0.16). However, major adverse cardiac event rates were significantly lower in the IVUS-guided group than that in the angiography-guided group (2.6% versus 7.1%; P=0.035; hazard ratio, 0.35; 95% confidence interval, 0.13–0.97). Occurrence of the composite of cardiac death or myocardial infarction was significantly lower in the IVUS-guided group (0%) than in the angiography-guided group (2.0%; P=0.045). The rates of target-vessel revascularization were not significantly different between the 2 groups. In the comparison between Resolute zotarolimus-eluting stent and Nobori biolimus-eluting stent, major adverse cardiac event rates were not significantly different (4.0% versus 5.7%; P=0.45). Conclusions—Although IVUS-guided CTO intervention did not significantly reduce cardiac mortality, this randomized study demonstrated that IVUS-guided CTO intervention might improve 12-month major adverse cardiac event rate after new-generation drug-eluting stent implantation when compared with conventional angiography-guided CTO intervention. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT01563952.

Comparison of Early Strut Coverage Between Zotarolimus- and Everolimus-Eluting Stents Using Optical Coherence Tomography

There have been no optical coherence tomographic (OCT) data directly comparing the pattern of strut coverage between the 2 second-generation drug-eluting stents in the early period. The aim of this prospective study was to evaluate early strut coverage using optical coherence tomography 3 months after Resolute zotarolimus-eluting stent (ZES-R) or everolimus-eluting stent (EES) implantation in de novo coronary artery lesions. A total of 40 patients who were suitable for the OCT procedure and consented to the study protocol were randomized 1:1 to receive either ZES-R or EES. Among these patients, 35 stented lesions (18 ZES-R, 17 EES) in 34 patients were evaluated by optical coherence tomography immediately and 3 months after stent implantation. Neointimal hyperplasia thickness, percentage of uncovered struts, and the proportion of malapposed struts were measured at 1-mm intervals. An uncovered strut was defined as having a neointimal hyperplasia thickness of 0 μm. At the 3-month OCT evaluation, mean neointimal hyperplasia thickness (ZES-R vs EES 74 ± 41 vs 75 ± 35 μm, p = 0.89) and mean percentage of uncovered struts (ZES-R vs EES 6.2 ± 6.9 vs 4.7 ± 5.1%, p = 0.62) were not significantly different between the groups. The percentage of malapposed struts was also similar between the groups (0.7 ± 2.2% for ZES-R and 0.7 ± 1.7% for EES, p = 0.64). Thrombi were documented in 3 stents (1 [5.6%] in a ZES-R vs 2 [11.8%] in EES, p = 0.60). In conclusion, early stent strut coverage on the basis of serial OCT evaluation was comparable between ZES-R and EES 3 months after stent implantation.

The relationship between post-stent strut apposition and follow-up strut coverage assessed by a contour plot optical coherence tomography analysis.

OBJECTIVES This study sought to evaluate the relationship between post-stent strut apposition and follow-up strut coverage using contour plot optical coherence tomographic analysis. BACKGROUND Tracking the fate of interested regions of struts at different time points has not been investigated. METHODS Post-intervention and 6-month follow-up optical coherence tomographic evaluations were performed in 82 patients treated with biolimus- (n = 37) or sirolimus-eluting stents (n = 45). Post-stent apposition was classified as embedded, apposed, or malapposed. For volumetric stent evaluation, the post-intervention strut-artery distance and the neointimal thickness at follow-up were measured as a function of the circumferential arc length and longitudinal stent length. Computer-generated contour plots of the strut-artery distance and neointimal thickness were compared. RESULTS The percentages of embedded and malapposed struts after intervention were 1.8% (Interquartile range [IQR]: 0.6% to 6.2%) and 2.3% (IQR: 0.5% to 5.2%), respectively. The percentages of uncovered and malapposed struts at 6 months were 16.0% (IQR: 7.4% to 33.3%) and 0% (IQR: 0% to 0.7%), respectively. The percentage of uncovered struts at 6 months varied significantly with post-stent strut apposition (0% [IQR: 0% to 11.4%] in embedded, 16.3% [IQR: 8.1% to 31.3%] in apposed, and 26.8% [IQR: 0% to 56.3%] in malapposed, p < 0.001 for all pairwise comparisons). In lesions without tissue prolapse, embedded struts were all covered (100% covered struts) compared with those with tissue prolapse (76.8% covered, p < 0.001). CONCLUSIONS The optical coherence tomography-guided optimization of stent strut apposition enhances strut coverage at follow-up. This comprehensive method for evaluating strut apposition may provide more useful information to understanding the serial changes in strut coverage. (Neointimal Coverage After Implantation of Biolimus Eluting Stent With Biodegradable Polymer: Optical Coherence Tomographic Assessment According to the Treatment of Dyslipidemia and Hypertension and the Types of Implanted Drug-Eluting Stents; NCT01502904).

Optical coherence tomography analysis of strut coverage in biolimus- and sirolimus-eluting stents: 3-month and 12-month serial follow-up.

BACKGROUND No randomized studies have been conducted to investigate serial changes in optical coherence tomography (OCT) analyses following implantation of biolimus-A9-eluting stents (BES) and sirolimus-eluting stents (SES). METHODS A total of 60 patients fulfilling the study criteria were randomly assigned into BES (n=30) and SES (n=30) implantation groups. Serial OCT evaluation at post-procedure, 3- and 12-month follow-up was performed in 46 patients [BES (n=22) and SES (n=24)]. OCT analyses were compared according to the type of stents and the follow-up time intervals. The percentage of uncovered struts was defined as the ratio of uncovered struts to total struts in all cross-sections. The primary endpoint was the percentage change (Δ) of uncovered struts in the 3- and 12-month follow-up samples. RESULTS The percentage of uncovered struts at the 3-month time period was not significantly different in the BES and SES groups; the median value (interquartile range) was 14.7% (0.0-23.4) versus 8.6% (0.7-21.5) (p=0.98), respectively. However, OCT at the 12-month follow-up showed a significantly lower percentage of uncovered struts [2.6% (0.8-5.6) versus 6.2% (1.7-14.7), (p=0.028), respectively] without significant difference of neointimal thickness. BES showed a greater reduction of percentage Δ of uncovered struts from 3-12 months than that of SES [-17.2±14.5% versus -7.7±16.3%, respectively (p=0.043)]. CONCLUSIONS Both drug-eluting stents showed a high percentage of incomplete strut coverage at 3 months. However, BES showed a significantly lower percentage of uncovered struts at 12 months compared to that of SES. This was achieved by superior strut coverage from 3 to 12 months.

Efficacy of Drug-Eluting Stents for Treating In-Stent Restenosis of Drug-Eluting Stents (from the Korean DES ISR Multicenter Registry Study [KISS])

There is currently no established standard treatment for in-stent restenosis (ISR) after the implantation of a drug-eluting stent (DES). The aim of this study was to investigate the efficacy of DES versus balloon angioplasty (BA) for the treatment of DES ISR in a multicenter registry cohort. After matching propensity scores of 805 patients with DES ISR treated with either DES (n = 422) or BA (n = 383), 268 matched pairs were selected and analyzed for major adverse cardiac events, a composite of death, myocardial infarction, and target-vessel revascularization, as the primary end point. Baseline clinical and lesion characteristics of the matched pairs were similar. Survival free of major adverse cardiac events at 2 years was higher with DES compared to BA (88.9% vs 78.7%, p <0.001), mainly because of higher TVR-free survival (92.4% vs 81.0%, p <0.001). Among various baseline variables, BA (hazard ratio 2.546, 95% confidence interval 1.412 to 4.593, p = 0.002) was the most important independent risk factor for recurrent target vessel revascularization, followed by acute coronary syndromes as the clinical presentation of DES ISR, and previous implantation of a sirolimus-eluting stent. Survival free of death, myocardial infarction, or stent thrombosis did not differ between the 2 groups. Whereas there was no significant difference in survival free of target vessel revascularization between DES and BA for focal ISR lesions, DES was superior to BA in diffuse ISR lesions (94.3% vs 75.2% at 2 years, p <0.001). In conclusion, compared to BA, the implantation of DES was safe and more effective in the treatment of DES ISR.

Prospective randomized comparison of clinical and angiographic outcomes between everolimus-eluting vs. zotarolimus-eluting stents for treatment of coronary restenosis in drug-eluting stents: intravascular ultrasound volumetric analysis (RESTENT-ISR trial).

AIMS At present no proven standard treatment for drug-eluting stent (DES) restenosis is available, and the efficacy and safety of everolimus-eluting stent (EES) and zotarolimus-eluting stent (ZES) for DES restenosis are limited. The purpose of this prospective, randomized 9-month intracoronary ultrasound (IVUS) and 3-year clinical follow-up study was to compare the effects of EESs and ZESs on neointima volume and major adverse cardiovascular events (MACEs) such as death, myocardial infarction (MI), target lesion revascularization (TLR) and stent thrombosis in DES restenosis patients. METHODS AND RESULTS Patients were eligible for this study if they were between 40 and 75 years old with in-stent restenosis >50% by quantitative coronary angiographic analysis in DES or within 5 mm of the stent edges with signs of ischaemia. Eligible patients (n = 304, 146 women and 158 men) were randomly assigned to receive either EES (158 patients) or ZES (146 patients). The primary endpoint of the study was to compare neointima volume between the EES and ZES groups at the 9-month follow-up IVUS. MACEs, including death, non-fatal MI, stent thrombosis and the need for repeated TLR within 3 years, were noted. The 9-month angiographic and IVUS follow-up showed no significant differences in late lumen loss (0.40 ± 0.56 vs. 0.45 ± 0.61 mm, P = 0.57, respectively) and neointima volume (0.51 ± 0.48 vs. 0.56 ± 0.54 mm3/1 mm, P = 0.47, respectively) in the EES and the ZES groups. Composite MACEs such as death, MI, stent thrombosis and TLR during 3-year follow-up were comparable between the two groups [15.8% (n = 25) in the EES group and 22.6% (n = 33) in the ZES group, P = 0.276], independent of de novo DES type, sex, age, body mass index, presence of diabetes, hypertension and dyslipidaemia. CONCLUSIONS Patients with first- and second-generation DES restenosis, both EES and ZES implantation were effective and safe in reducing neointima volume and late loss with a comparable rate of MACEs independent of cardiovascular risk factors.