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Background: Clopidogrel monotherapy improved clinical outcomes compared with aspirin monotherapy during a chronic maintenance period in patients who underwent coronary stenting in the HOST-EXAM (Harmonizing Optimal Strategy for Treatment of Coronary Artery Stenosis-Extended Antiplatelet Monotherapy) trial. However, it is uncertain whether the beneficial effect of clopidogrel over aspirin is different according to the renal function., Methods and Results: We conducted a post hoc analysis of the HOST-EXAM trial. Chronic kidney disease (CKD) was defined as baseline estimated glomerular filtration rate <60 mL/min per 1.73 m 2 . The primary end point was a composite of all-cause death, nonfatal myocardial infarction, stroke, readmission due to acute coronary syndrome, and Bleeding Academic Research Consortium bleeding type ≥3, during the 2-year follow up. Among the 5438 patients enrolled in the HOST-EXAM trial, 4844 patients (mean age, 63.3±10.6 years; 74.9% men) with a baseline creatinine value were analyzed in this study. A total of 508 (10.5%) patients had CKD, who were at higher risk of the primary end point compared with those without CKD (hazard ratio [HR], 2.01 [95% CI, 1.51-2.67]). Clopidogrel monotherapy was associated with a lower rate of the primary end point in both patients with CKD (HR, 0.74 [95% CI, 0.44-1.25]) and patients without CKD (HR, 0.71 [95% CI, 0.56-0.91]). No significant interaction was observed between the treatment effect and CKD status ( P for interaction=0.889)., Conclusions: During the chronic maintenance period after coronary stenting, the risk of thrombotic and bleeding events was significantly higher in patients with CKD compared with those without CKD. There was no statistical difference in the treatment effect of clopidogrel monotherapy in those with versus without CKD.

Background: Optimal antiplatelet monotherapy during the chronic maintenance period in patients who undergo coronary stenting is unknown. We aimed to compare head to head the efficacy and safety of aspirin and clopidogrel monotherapy in this population., Methods: We did an investigator-initiated, prospective, randomised, open-label, multicentre trial at 37 study sites in South Korea. We enrolled patients aged at least 20 years who maintained dual antiplatelet therapy without clinical events for 6-18 months after percutaneous coronary intervention with drug-eluting stents (DES). We excluded patients with any ischaemic and major bleeding complications. Patients were randomly assigned (1:1) to receive a monotherapy agent of clopidogrel 75 mg once daily or aspirin 100 mg once daily for 24 months. The primary endpoint was a composite of all-cause death, non-fatal myocardial infarction, stroke, readmission due to acute coronary syndrome, and Bleeding Academic Research Consortium (BARC) bleeding type 3 or greater, in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT02044250., Findings: Between March 26, 2014, and May 29, 2018, we enrolled 5530 patients. 5438 (98·3%) patients were randomly assigned to either the clopidogrel group (2710 [49·8%]) or to the aspirin group (2728 [50·2%]). Ascertainment of the primary endpoint was completed in 5338 (98·2%) patients. During 24-month follow-up, the primary outcome occurred in 152 (5·7%) patients in the clopidogrel group and 207 (7·7%) in the aspirin group (hazard ratio 0·73 [95% CI 0·59-0·90]; p=0·0035)., Interpretation: Clopidogrel monotherapy, compared with aspirin monotherapy during the chronic maintenance period after percutaneous coronary intervention with DES significantly reduced the risk of the composite of all-cause death, non-fatal myocardial infarction, stroke, readmission due to acute coronary syndrome, and BARC bleeding type 3 or greater. In patients requiring indefinite antiplatelet monotherapy after percutaneous coronary intervention, clopidogrel monotherapy was superior to aspirin monotherapy in preventing future adverse clinical events., Funding: ChongKunDang, SamJin, HanMi, DaeWoong, and the South Korea Ministry of Health and Welfare., Competing Interests: Declaration of interests H-SK has received research grants or speaker's fees from Medtronic, Abbott Vascular, Edwards Life Science, Boston Scientific, Terumo, Biotronik and Dio, AmGen, Pfizer, AstraZeneca, MSD, Daiichi Sankyo, and Boehringer Ingelheim. B-KK has received institutional research grants from Abbott Vascular and Philips. KWP reports fees from Daiichi Sankyo, AstraZeneca, Sanofi, Bristol-Myers Squibb, Bayer, and Pfizer outside the submitted work. All other authors declare no competing interests., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Ticagrelor reduced the rate of myocardial infarction and death compared with clopidogrel in patients with acute coronary syndrome. However, little is understood about chronic treatment of ticagrelor on microvascular dysfunction. The objective of this study was to assess the impact of ticagrelor maintenance treatment on microvascular system and coronary flow in comparison with clopidogrel., Methods: This study was a nonblinded, open-label, parallel-group, prospective, randomized controlled trial that enrolled 120 patients with acute coronary syndrome requiring stent implantation. Patients were randomized into the ticagrelor (180 mg loading dose, 90 mg twice daily thereafter) or clopidogrel (300 to 600 mg loading dose, 75 mg daily thereafter) group. The primary end point was coronary microvascular dysfunction as measured by an index of microcirculatory resistance (IMR) at 6 months after treatment., Results: The baseline clinical characteristics and physiological parameters, such as fractional flow reserve, coronary flow reserve, and IMR, did not differ between the ticagrelor and clopidogrel groups. Six-month follow-up physiological data showed that the IMR value was significantly lower in the ticagrelor group than the clopidogrel group (15.57±5.65 versus 21.15±8.39, P <0.01), and coronary flow reserve was higher in the ticagrelor group than in the clopidogrel group (3.85±0.72 versus 3.37±0.76, P <0.01). However, there was no difference in fractional flow reserve (0.87±0.08 versus 0.87±0.09, P =0.94) between the 2 groups. The improvement in IMR after 6 months of treatment was higher in the ticagrelor group ( P <0.01). Analyses of 223 nonculprit vessels of registered patients based on physiological results showed no differences in baseline fractional flow reserve (0.93±0.13 versus 0.92±0.09, P =0.58), coronary flow reserve (3.62±1.27 versus 3.51±1.24, P =0.16), or IMR (21.37±12.37 versus 24.19±21.08, P =0.22) or in follow-up fractional flow reserve (0.91±0.09 versus 0.91±0.08, P =0.67), coronary flow reserve (3.91±1.22 versus 3.75±1.16, P =0.36), or IMR (19.43±10.32 versus 21.52±18.90, P =0.34) between the 2 groups., Conclusions: Compared with clopidogrel, 6 months of ticagrelor therapy significantly improved microvascular dysfunction in acute coronary syndrome patients with stent implantation., Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02618733.

It has been previously demonstrated that ticagrelor can reduce mortality compared to clopidogrel in acute coronary syndrome (ACS) patients. However, the mechanism for this mortality reduction remains uncertain. The objective of the present study is to assess the impact of chronic ticagrelor treatment on microvascular circulation. A total of 120 participants aged 20-85 years with clinical diagnosis of ACS will be randomized in a 1:1 fashion to the following two groups: ticagrelor 90 mg twice daily; clopidogrel 75 mg once daily. To evaluate the status of microcirculation, the primary end point is coronary microvascular dysfunction measured using an index of microcirculatory resistance (IMR) at 6 months after receiving the study agent. The purpose of this trial is to investigate whether ticagrelor, beyond its antiplatelet efficacy, could improve coronary microcirculation more effectively than clopidogrel for patients with ACS.

Background: Whether genetic polymorphisms (GP) impact residual platelet aggregation (RPA) following prasugrel is unclear, especially during maintenance phase. We assessed the influence of CYP2C19 GP carriers on RPA in the prospective observational cohort study. Methods and Results: All post-stent patients (n = 206) received prasugrel 60 mg loading and either 5 or 10 mg daily maintenance with aspirin100 mg. RPA levels by light transmission aggregometry (LTA), multiplate electrode aggregometry (MEA), and VerifyNow (P2Y12 reaction units, PRU) with CYP2C19 GP were measured simultaneously. Demographics and clinical characteristics were not useful for predicting response after prasugrel. GP carriers exhibited higher RPA (PRU: p = 0.001, LTA: p = 0.001, MEA: p = 0.023) than noncarriers. CYP2C19 carriers had higher RPA for 5 mg (n = 35; LTA: p = 0.043, MEA: p = 0.023) and reached significance for 10 mg (n = 27; LTA: p = 0.001, PRU: p = 0.001) prasugrel. When divided into extensive, intermediate, and poor metabolizers, all exhibited statistical differences among the 3 groups (LTA: 14.9 ± 12.3%, 22.6 ± 14.9%, 22.9 ± 15.6%, p = 0.002; PRU: 104.1 ± 70.8%, 141.8 ± 78.0%, 151.0 ± 84.8%, p = 0.003; MEA: 19.7 ± 8.9%, 24.4 ± 12.2%, 28.1 ± 14.7%, p = 0.002). Conclusion: CYP2C19 GP impacts RPA during maintenance phase prasugrel in Korean outpatients. This effect is consistent for both of the approved prasugrel doses potentially affecting long-term outcomes including bleeding risks. However, the clinical utility of these findings is still uncertain, and requires more evidence from larger randomized trials beyond East Asians. [ABSTRACT FROM AUTHOR]

The novel antiplatelet agent ticagrelor has been demonstrated to exert a faster and more powerful inhibition of platelet aggregation in comparison to clopidogrel in coronary artery disease patients. However, a ticagrelor dose of 90 mg twice daily might not be suitable for patients of East Asian ethnicity, and has not been fully investigated. The aim of this study was to assess the effects of low loading doses (LD, 90 mg) and maintenance doses (MD, 90 mg daily) of ticagrelor in comparison to clopidogrel (600 mg LD, 75 mg daily MD) in healthy Korean volunteers. Twelve subjects were randomized into two groups, receiving either clopidogrel (600 mg LD, followed by 75 mg MD daily for 5 days) or ticagrelor (90 mg LD, followed by 90 mg MD daily for 5 days). Following a 2-week washout period, the treatments were switched between the groups. Three platelet function assessment methods which included light transmission aggregometry (LTA), the VerifyNow assay and multiple electrode platelet aggregometry (MEA) were then used to serially measure platelet function at various time points (baseline, 0.5, 2, 6, 24, 26, 120 and 122 h). The mean IPA to 10 µM ADP in the ticagrelor group was significantly higher than that for the clopidogrel group at the 0.5, 2, 6, 26 and 122 h time points (p ≤ 0.001). However, there was no significant difference between the two groups at the 24- and 120-hour time points (p > 0.05). The assay results produced by the other two platelet function tests (VerifyNow and MEA) were similar to those obtained by LTA. The low loading and maintenance doses of ticagrelor (90 mg LD, 90 mg daily MD) cause a more rapid and potent inhibition of platelet function when compared to clopidogrel (600 mg LD and 75 mg MD). Additionally, at the lowest value of platelet inhibition strength, oral once-daily administration of ticagrelor was no less efficacious than clopidogrel at the 24- and 120-hour time points. Due to a large diurnal variation occurring with a single daily dose, a lower dose twice-daily could be a better option for patients of East Asian ethnicity. [ABSTRACT FROM PUBLISHER]

Objectives: This study sought to test the noninferiority of triple antiplatelet therapy (TAT) versus double-dose clopidogrel dual antiplatelet therapy (DDAT) in patients undergoing percutaneous coronary intervention (PCI). Background: Antiplatelet regimen is an integral component of medical therapy after PCI. A 1-week duration of doubling the dose of clopidogrel was shown to improve outcome at 1 month compared with the conventional dose in patients with acute coronary syndrome undergoing PCI. Yet in Asia, the addition of cilostazol is used more commonly than DDAT in high-risk patients. Methods: We randomly assigned 3,755 all-comers undergoing PCI to either TAT or DDAT, which was continued for 1 month, to test the noninferiority of TAT versus DDAT. The primary outcome was the cumulative incidence of net clinical outcome at 1 month post-PCI defined as the composite of cardiac death, nonfatal myocardial infarction, stent thrombosis, stroke, and PLATO (Platelet Inhibition and Patient Outcomes) major bleeding. Results: TAT was noninferior to DDAT with respect to the primary outcome, which occurred in 1.2% and 1.4% of patients, respectively (−0.22% absolute difference, 0.34% 1-sided 97.5% confidence interval, p = 0.0007 for noninferiority; hazard ratio: 0.85; 95% confidence interval: 0.49 to 1.48; p = 0.558 for superiority). The individual risks of cardiac death, nonfatal myocardial infarction, stent thrombosis, stroke, and PLATO major bleeding did not differ significantly between the 2 groups. There were no significant between-group differences in the treatment effect with regard to the rate of the primary outcome. Conclusions: The adjunctive use of cilostazol was noninferior to doubling the dose of clopidogrel for 1 month in all-comers undergoing PCI with exclusively drug-eluting stents. (Harmonizing Optimal Strategy for Treatment of Coronary Artery Stenosis–SAfety & EffectiveneSS of Drug-ElUting Stents & Anti-platelet REgimen [HOST-ASSURE]; NCT01267734) [Copyright &y& Elsevier]

Background: Patients with reduced responsiveness to clopidogrel often have diminished platelet inhibition, a factor associated with increased rates of major adverse cardiovascular events. Clinical trials that have focused on reducing high on-treatment platelet reactivity (HPR) with an additional loading dose of clopidogrel have reported varying effects. Prasugrel, a newer thienopyridine, exhibits a more consistent antiplatelet effect and more rapid onset time when compared to clopidogrel. We hypothesize that prasugrel reloading would be more effective than clopidogrel reloading in patients with HPR after an initial loading dose of clopidogrel. Method/Design: Comparison of Prasugrel and Clopidogrel Reloading on High Platelet Reactivity in Clopidogrelloaded Patients Undergoing Percutaneous Coronary Intervention (PRAISE-HPR) is a prospective, randomized, openlabel, active controlled study. A total of 76 patients undergoing percutaneous coronary intervention (PCI), with HPR after administration of a loading dose of clopidogrel will be randomly assigned to either prasugrel or clopidogrel groups, and patients in each group will be reloaded with 20 mg of prasugrel or 300 mg of clopidogrel. The primary endpoint will be HPR at 24 hours after PCI, as determined by the VerifyNow assay during the study period. The rate of sustained high platelet reactivity and 30-day clinical outcomes will also be measured. Discussion: PRAISE-HPR is a randomized controlled clinical trial to investigate the efficacy and safety of reloading prasugrel and clopidogrel in suppressing residual high platelet reactivity. The results will be made publicly available in the year 2013. [ABSTRACT FROM AUTHOR]

Objective The impact of thienopyridine reloading on clinical outcomes, and residual high platelet reactivity (HPR) is unclear. We sought to compare the HRP-related effect of prasugrel and clopidogrel reloading in the already clopidogrel-loaded patients undergoing percutaneous coronary intervention (PCI). Materials and methods In this prospective, two-center, randomized, open-label study, patients with HPR who had undergone PCI after a clopidogrel (300–600 mg) loading dose (LD) were enrolled. Among screened (n = 153), HPR was determined in seventy-six patients, who were randomized to either repeated clopidogrel (300 mg LD, followed by 75 mg MD daily) or prasugrel (20 mg LD, followed by 5 mg MD daily). The primary endpoint was HPR at 24 h after PCI, as determined by the VerifyNow assay. The rates of sustained high and low platelet reactivity, periprocedural myocardial injury (PMI) and 30-day clinical outcomes were also assessed. Results Higher inhibition of platelet reactive units (PRU) was observed in the prasugrel group than after clopidogrel reloading (Pre-PCI: 284.4 ± 32.0 vs 279.5 ± 32.5, p = 0.504; Post-PCI: 100.0 ± 67.0 vs 202.9 ± 65.8, p < 0.001; 30 days: 170.8 ± 69.8 vs 215.1 ± 62.4, p = 0.007). There were less HRP post-PCI after prasugrel compared with the clopidogrel group (2.7 vs 36.1%, p < 0.001). However, reloading with prasugrel did not reduce PMI compared to clopidogrel (36.8% vs 39.5%, p = 0.813). Conclusion Prasugrel reloading led to a greater reduction in HPR, but similar with clopidogrel PMI in post-PCI patients. Larger randomized evidence is needed for optimization of loading strategies with thienopyridines. Clinical Trial Registration Information: NCT01609647 . [ABSTRACT FROM AUTHOR]

Background Despite advances in modern anti-platelet strategies, clopidogrel still remains the cornerstone of dual anti-platelet therapy (DAPT) in patients undergoing percutaneous coronary interventions (PCI). There is some inconclusive evidence that response after clopidogrel may be impacted by concomitant medications, potentially affecting clinical outcomes. Sustained released nitrates (SRN) are commonly used together with clopidogrel in post-PCI setting for mild vasodilatation and nitric oxide-induced platelet inhibition. Methods We prospectively enrolled 458 patients (64.5 ± 9.6 years old, and 73.4% males) following PCI undergoing DAPT with clopidogrel and aspirin. Platelet reactivity was assessed by the VerifyNow™ P 2 Y12 assay at the maintenance outpatient setting. Results Concomitant SRN (n = 266) significantly (p = 0.008) enhanced platelet inhibition after DAPT (251.6 ± 80.9 PRU) when compared (232.1 ± 73.5 PRU) to the SRN-free (n = 192) patients. Multivariate logistic regression analysis with the cut-off value of 253 PRU for defining heightened platelet reactivity confirmed independent correlation of more potent platelet inhibition during DAPT and use of SRN (Relative risk = 1.675; Odds ratio [1.059–2.648]; p = 0.027). In contrast, statins, calcium-channel blockers, beta blockers, angiotensin receptor blockers, ACE-inhibitors, diuretics, and anti-diabetic agents did not significantly impact platelet inhibition following DAPT. Conclusion The synergic ability of SRN to enhance response during DAPT may have important clinical implications with regard to better cardiovascular protection, but extra bleeding risks, requiring further confirmation in a large randomized study. [ABSTRACT FROM AUTHOR]

Abstract: Background: Clopidogrel resinate is a resinate complex of (+)-clopidogrel optical isomer, wherein the (+)-clopidogrel isomer binds to a water-soluble cation exchange resin via sulfonic acid groups. It was approved by the Korean Food and Drug Administration on the basis of a Phase I study that demonstrated the bioequivalence of clopidogrel resinate and clopidogrel bisulfate. However, there are no available data regarding efficacy and tolerability in patients with vascular disease. Objective: The goal of this study was to investigate the antiplatelet efficacy and tolerability of clopidogrel resinate in patients with coronary heart disease (CHD) or CHD-equivalent risks. Methods: This study was a Phase IV, randomized, double-blind, double-dummy, parallel-group, noninferiority trial. We prospectively recruited patients in 10 centers between March 2008 and July 2008. Patients who had documented CHD or CHD-equivalent risks were randomly assigned to 1 of 3 groups: group A, aspirin (100 mg) + clopidogrel bisulfate placebo + clopidogrel resinate placebo; group B, aspirin (100 mg) + clopidogrel bisulfate placebo + clopidogrel resinate (75 mg); or group C, aspirin (100 mg) + clopidogrel bisulfate (75 mg) + clopidogrel resinate placebo. The primary outcome was the percent P2Y12 inhibition after medication, assessed by using a point-of-care assay. If the 1-sided 90% upper confidence limit for the difference was less than the prespecified delta value (–5.7), clopidogrel resinate would be considered noninferior to clopidogrel bisulfate. The secondary outcome, the prevalence of adverse events (AEs) associated with study medications, was assessed at each visit by direct interview. Results: A total of 314 patients (mean [SD] age, 62.2 [9.0] years; male 63.7%; weight, 67.3 [13.6] kg [range, 45–102 kg]; all Asian) were enrolled, and 287 patients finished the study (group A, n = 97; group B, n = 90; and group C, n = 100). Eight patients took no study medications and were excluded from the tolerability and efficacy analyses. Nineteen patients discontinued the study because of protocol violation (n = 15), adverse events (n = 3), or voluntary withdrawal (n = 1) and were excluded from the efficacy analysis. There were no significant differences in baseline clinical characteristics among the groups except for the frequency of a history of CHD (group A, 85.4%; group B, 73.0%; and group C, 88.3%; P = 0.01). Patients treated with either type of clopidogrel showed significant inhibition (mean [SD]) of P2Y12 (group A, –5.9% [15.1%]; group B, 23.4% [21.9%]; and group C, 19.5% [23.8%]; P < 0.001). Differences between clopidogrel resinate and clopidogrel bisulfate in the inhibition of P2Y12 did not exceed the predetermined value for inferiority (P for noninferiority, 0.02; 90% CI, −0.9 to 10.3). In the tolerability analysis, there was no mortality during the study period and no significant differences between groups in the frequency of AEs and serious AEs (AEs: group A, 33.0%; group B, 26.0%; and group C, 23.3% [P = 0.27]; serious AEs: group A, 1.0%; group B, 3.0%; and group C, 1.0% [P = 0.42]). One patient in group B underwent coronary stent implantation for treatment of stable angina. Conclusions: In this small, selected Asian patient population, differences in the platelet inhibition efficacies of clopidogrel resinate and clopidogrel bisulfate did not exceed the predetermined limits for noninferiority. The differences in tolerability between the 2 drugs did not reach statistical significance. ClinicalTrials.gov identifier: NCT00947843. [Copyright &y& Elsevier]