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Background The clinical value of intracoronary imaging for percutaneous coronary intervention (PCI) guidance is well acknowledged. Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) are the most commonly used intravascular imaging to guide and optimize PCI in day-to-day practice. However, the comparative effectiveness of IVUS-guided versus OCT-guided PCI with respect to clinical end points remains unknown. Methods and design The OCTIVUS study is a prospective, multicenter, open-label, parallel-arm, randomized trial comparing the effectiveness of 2 imaging-guided strategies in patients with stable angina or acute coronary syndromes undergoing PCI in Korea. A total of 2,000 patients are randomly assigned in a 1:1 ratio to either an OCT-guided PCI strategy or an IVUS-guided PCI strategy. The trial uses a pragmatic comparative effectiveness design with inclusion criteria designed to capture a broad range of real-world patients with diverse clinical and anatomical features. PCI optimization criteria are predefined using a common algorithm for online OCT or IVUS. The primary end point, which was tested for both noninferiority (margin, 3.1 percentage points for the risk difference) and superiority, is target-vessel failure (cardiac death, target-vessel myocardial infarction, or ischemia-driven target-vessel revascularization) at 1 year. Results Up to the end of July 2020, approximately 1,200 "real-world" PCI patients have been randomly enrolled over 2 years. Enrollment is expected to be completed around the midterm of 2021, and primary results will be available by late 2022 or early 2023. Conclusion This large-scale, multicenter, pragmatic-design clinical trial will provide valuable clinical evidence on the relative efficacy and safety of OCT-guided versus IVUS-guided PCI strategies in a broad population of patients undergoing PCI in the daily clinical practice.

Background Although the need to detect restenosis has diminished in the contemporary practice of percutaneous coronary intervention (PCI) with drug-eluting stents (DES), the surveillance of ischemia owing to restenosis or disease progression deserves attention in high-risk PCI settings. It is unknown whether follow-up strategy of routine noninvasive functional testing potentially reduces the risk of major cardiovascular events in high-risk PCI patients. Methods The POST-PCI study is an investigator-initiated, multicenter, prospective randomized trial comparing the effectiveness of two follow-up strategies in patients with high-risk anatomic or clinical characteristics who underwent PCI. Study participants were randomly assigned to either (1) the routine noninvasive stress testing (exercise electrocardiography, nuclear stress imaging, or stress echocardiography) at 12 months post-PCI or (2) the standard-care without routine testing. In the routine stress testing group, depending on the testing results, all clinical decisions regarding subsequent diagnostic or therapeutic procedures were at the treating physician's discretion. The primary endpoint was a composite outcome of death from any causes, myocardial infarction, or hospitalization for unstable angina at 2 years post-PCI. Results More than 1700 high-risk PCI patients have been randomized over 2.0 years at 11 major cardiac centers in Korea. Conclusion This pragmatic POST-PCI trial will provide valuable clinical evidence on the effectiveness of follow-up strategy of routine noninvasive stress testing in high-risk PCI patients.

Background Percutaneous coronary intervention (PCI) has been developed by drug-eluting stent (DES), but stent implantation has brought the issue of stent thrombosis and optimal antiplatelet therapy. Guidelines recommend at least 6- to 12 months of dual antiplatelet therapy (DAPT) with aspirin and a P2Y 12 receptor inhibitor such as clopidogrel. Beyond DAPT after PCI with DES, however, there has been still a debate for antiplatelet regimen. Therefore, we report on the upcoming HOST-EXAM trial (NCT02044250), which will evaluate the efficacy and safety of aspirin and clopidogrel monotherapies beyond DAPT after DES implantation. Trial design The HOST-EXAM is a prospective, randomized, open-label, multicenter, comparative effectiveness trial, to compare between clopidogrel (75 mg once daily) and aspirin (100 mg once daily) as long-term antiplatelet agents. A total of 5,530 patients with no clinical events during combined antiplatelet therapy for 12±6 months after index PCI will be screened, enrolled, and randomized to either group (1:1 ratio) receiving antiplatelet monotherapy for 2 years. The primary endpoint will be the rate of clinical events defined as a composite of all-cause death, nonfatal myocardial infarction, stroke, readmission due to acute coronary syndrome, or major bleeding at 24 months after randomization. Conclusions The HOST-EXAM will be the first large-scale randomized controlled study to directly compare the efficacy and safety of long-term antiplatelet monotherapy beyond DAPT after DES implantation. This study will provide clinical evidence to establish optimal regimen for long-term antiplatelet therapy after DES implantation.

Background Data on strut surface coverage of second-generation drug-eluting stents (DES) are limited. We investigated stent strut coverage of resolute zotarolimus-eluting stent (ZES-R) or everolimus-eluting stent (EES) at 9 months after implantation using optical coherence tomography (OCT). Methods ComparisOn of neointimal coVerage betwEen zotaRolimus-eluting stent and everolimus-eluting stent using Optical Coherence Tomography (COVER OCT) is a prospective, randomized, multicenter trial comparing ZES-R to EES using OCT at 9 months after stent implantation. The primary end point was the rate of stent strut coverage at 9 months. Results A total of 51 patients were randomized to receive either ZES-R (ZES-R group) or EES (EES group), and 47 stents (24 ZES-R and 23 EES) in 44 of 51 patients were evaluated by OCT both immediately after stent implantation and at 9 months. The neointimal thickness was not significantly different between the 2 groups at 9 months (ZES-R vs EES: 139 ± 58 vs 124 ± 42 μm, P = .31). The mean percentages of uncovered stent struts were 3.3% for ZES-R versus 3.4% for EES at 9 months ( P = .51). The proportions of malapposed struts immediately after stent implantation ( P = .89) and at 9-month follow-up ( P = .34) were 0.8% and 0.7% for ZES-R versus 1.0% and 0.1% for EES, respectively. Thrombi were documented in 1 stent (1 [4.2%] in ZES-R vs 0 [0%] in EES). Conclusion According to the sequential OCT evaluation, ZES-R and EES showed comparable neointimal thickness and the rate of uncovered stent strut at 9 months after stent implantation.

The purpose of this study was to investigate the vascular response of zotarolimus-eluting stent (ZES) and sirolimus-eluting stent (SES) using serial intravascular ultrasound (IVUS).Data were obtained from the Endeavor Drug-Eluting Coronary Stent System Versus the Center Siromlimus-Eluting Coronary Stent System in De Novo Native Coronary Artery Lesions (ENDEAVOR) III trial, a randomized study comparing ZES and SES for the treatment of de novo native coronary artery lesions. Serial (baseline and 8-month follow-up) IVUS was available in 258 patients (190 ZES, 68 SES).At 8 months, ZES had greater percentage of neointimal volume index (ZES 1.1 +/- 0.8 mm3/mm vs SES 0.2 +/- 0.1 mm3/mm, P.01), resulting in smaller lumen volume index (6.0 +/- 2.0 mm3/mm vs 7.0 +/- 2.1 mm3/mm, P.05). Zotarolimus-eluting stents showed larger IVUS-detectable neointimal coverage over stent surface (50.2% vs 10.5%, P.01) and greater mean neointimal thickness (0.19 +/- 0.07 mm vs 0.10 +/- 0.06 mm, P.01). Zotarolimus-eluting stents had a significantly lower incidence of late-acquired incomplete stent apposition.Zotarolimus-eluting stent is associated with a significantly greater amount of neointimal hyperplasia compared with SES. This amount of hyperplasia in ZES is distributed throughout the stent at 8-month follow-up.

Paclitaxel-eluting stents (PESs) have been shown to inhibit neointimal hyperplasia after percutaneous coronary intervention. Coroflex Please (B Braun, Melsungen, Germany) is a newly developed PES. We compared the clinical and angiographic efficacy of Coroflex Please with Taxus Liberte (Boston Scientific, Natick, MA) in a real-world practice.We performed a prospective, open-label, randomized, controlled study that enrolled 945 patients undergoing percutaneous coronary interventions in 18 centers in Korea. The primary end point was clinically driven target vessel revascularization at 9 months. The baseline characteristics were mostly similar and comparable between 2 groups. At 9 months, the incidence of clinically driven target vessel revascularization was 14.6% for Coroflex and 6.4% for Taxus, which was significantly different (hazard ratio 2.43, 95% CI 1.50-3.94, noninferiority P value = 1.000). This is well corroborated by the difference of in-stent late loss between 2 stents (0.71 ± 0.64 mm vs 0.52 ± 0.50 mm, P.001) by 9-month follow-up angiography (n = 415 vs 215). Among secondary clinical end points, stent thrombosis (definite and probable) for 1 year was 2.2% in Coroflex and 1.3% in Taxus (P = .317). Also, myocardial infarction for 9 months was higher in Coroflex group than that in Taxus (4.9% vs 1.6%, P = .012), which was partly contributed by the higher incidence of periprocedural myocardial infarction in Coroflex arm (2.2% vs 0.3%, P = .028).Coroflex Please was inferior to Taxus Liberte with regard to clinical and angiographic efficacy.

Background The optimal loading dose of clopidogrel in Asian patients with ST-segment elevation myocardial infarction (STEMI) has not been fully investigated. We compared bleeding, vascular complications, and midterm outcomes of a 300-mg versus a 600-mg loading dose of clopidogrel in a large series of Korean patients with STEMI undergoing primary percutaneous coronary intervention (PCI). Methods A total of 2,664 STEMI patients (age 61.96 ± 11.91 years, men 70.4%) who underwent primary PCI were enrolled in this study. The patients were divided into a standard loading dose group (300 mg; n = 1,447 patients) and a high loading dose group (600 mg; n = 1,217 patients). Bleeding and vascular complications, and in-hospital and clinical outcomes up to 12 months were compared between the 2 groups. Results In-hospital bleeding and vascular complications were similar between the 2 groups. There were no differences in bleeding and vascular complications and in 1- and 12-month clinical outcomes, including mortality, myocardial infarction, repeated PCI, and major adverse cardiac events, between the 2 groups. These findings were consistent even after the propensity score–matched analysis. Conclusions The standard loading dose of clopidogrel may be as safe and similarly effective as the high loading dose in Asian STEMI patients undergoing primary PCI.

Background Only limited data are available for the recent trend of optimal evidence-based medical therapy at discharge after acute myocardial infarction (AMI) in Asia. We evaluated the predictors for the use of optimal evidence-based medical therapy at discharge and the association between discharge medications and 6-month mortality after AMI. Methods Between November 2005 and January 2008, we evaluated the discharge medications among 9,294 post-MI survivors who did not have any documented contraindications to antiplatelet drugs, β-blockers, angiotensin-converting enzyme inhibitors (ACE-Is)/angiotensin II receptor blockers (ARBs), or statins in the Korea Acute Myocardial Infarction Registry. Optimal evidence-based medical therapy was defined as the use of all 4 indicated medications. Results Of these patients, 4,684 (50.4%) received all 4 medications at discharge. The discharge prescription rates of antiplatelet drugs, β-blockers, ACE-Is/ARBs, and statins were 99.0%, 72.7%, 81.5%, and 77.2%, respectively. In multivariate analysis, advanced age, lower systolic blood pressure, higher Killip class at admission, left ventricular systolic dysfunction, higher blood creatinine level, lower total cholesterol levels, and coronary artery bypass grafting during hospitalization were independently associated with less use of optimal evidence-based medical therapy. In contrast, patients who underwent percutaneous coronary intervention were more likely to use optimal medications. In Cox proportional hazards model, optimal evidence-based medical therapy was an independent predictor of 6-month mortality after adjusting clinical characteristics and angiographic and procedural data. Conclusions The optimal evidence-based medical therapy is prescribed at suboptimal rates, particularly in patients with high-risk features. New educational strategies are needed to increase the use of these secondary preventive medical therapies.

Whether low-molecular-weight heparin (LMWH) is superior to unfractionated heparin (UFH) in acute ST-segment elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (PCI) with drug-eluting stents (DESs) remains unclear.A total of 3,372 STEMI patients who underwent primary PCI with DESs received either LMWH (n = 1,531 patients, subcutaneous enoxaparin 1 mg/kg, bid for 3-5 days plus reduced dose of UFH [50 U/kg] during PCI) or UFH alone (n = 1,841 patients, intravenous bolus injection of 5,000 U, followed by 24,000 U/d infusion for at least 48 hours). The bleeding events and clinical outcomes during in-hospital and at 8 months were compared.The incidences of major and minor bleeding events were similar between the 2 groups. Multivariable Cox regression analysis showed that LMWH group had lower incidences of cardiac death (adjusted odds ratio [OR] 0.55, 95% CI 0.39-0.77, P.001), total death (adjusted OR 0.50, 95% CI 0.37-0.68, P.001), and total major adverse cardiac events (adjusted OR 0.77, 95% CI 0.62-0.95, P = .017) at 8 months as compared with UFH group. Similar results were obtained across different subgroups including different DESs, age, and sex.The LMWH enoxaparin combined with reduced dose of UFH (50 U/kg) administration as an adjunctive antithrombotic therapy in STEMI patients undergoing primary PCI with DESs seems to be safe and efficacious. However, randomized clinical trials are needed to confirm this conclusion.