Ticagrelor versus prasugrel in patients with high on-clopidogrel treatment platelet reactivity after PCI: The ISAR-ADAPT-PF study.

Patients with high on-treatment platelet reactivity (HTPR) on clopidogrel are at high risk for adverse cardiovascular events after percutaneous coronary intervention (PCI). The aim of the ISAR-ADAPT-PF study was to assess the antiplatelet efficacy of ticagrelor versus prasugrel in patients with HTPR on clopidogrel. In a prospective and randomized clinical study, 70 patients with HTPR on clopidogrel loading dose (LD) within 24 h post PCI were assigned to receive either ticagrelor [180 mg LD followed by 90 mg maintenance dose (MD) twice daily] or prasugrel (60 mg LD followed by 10 mg MD once daily). The adenosine diphosphate-induced platelet aggregation assessed on the Multiplate analyzer on day 2 after randomization (primary end point) was as follows: the mean difference between the two treatment groups was 6 aggregation units (AU) × min with an upper 95% confidence interval (CI) of 41 AU × min, which was greater than the predefined noninferiority margin of 18 AU × min (P for noninferiority = 0.29). However, no significant differences in absolute platelet reactivity levels between ticagrelor- versus prasugrel-treated patients at that time point were observed (138 ± 100 AU × min vs. 132 ± 64 AU × min, P for superiority = 0.77). In conclusion, neither drug was statistically more effective for inhibition of platelet aggregation in patients with HTPR on clopidogrel post PCI, although the study could not formally demonstrate the assumed noninferiority of ticagrelor versus prasugrel.

Impact of immature platelets on platelet response to ticagrelor and prasugrel in patients with acute coronary syndrome.

AIMS: The influence of reticulated platelets (RPs) on platelet inhibition by ticagrelor when compared with prasugrel is unknown. We aimed to determine the influence of RPs on adenosine diphosphate- (ADP-) induced platelet aggregation in patients with acute coronary syndrome who were randomly assigned to receive either ticagrelor or prasugrel for P2Y12 receptor inhibition. METHODS AND RESULTS: One hundred and twenty-four patients were prospectively enrolled. The immature platelet fraction (IPF) was measured by an automated haematoanalyzer and platelet aggregation was assessed by multiple electrode aggregometry. In a subgroup of patients (n = 28) ADP-induced P-selectin expression was measured in dependence of the time point of study drug intake in RPs that were discriminated from mature platelets by thiazole-orange (TO) staining. The primary endpoint was the correlation of platelet aggregation and IPF in ticagrelor- vs. prasugrel-treated patients. Platelet aggregation significantly correlated with IPF in patients who received prasugrel (r = 0.41, P < 0.001). In contrast, no correlation between IPF and platelet aggregation was observed in ticagrelor-treated patients (r = 0.08, P = 0.51, P for difference of correlation coefficients P = 0.05). Within the TO-positive RP fraction, P-selectin expression was significantly higher in prasugrel when compared with ticagrelor-treated individuals (prasugrel 18.6 ± 16.0% vs. ticagrelor 11.5 ± 6.0%, P = 0.047). A time-dependent P-selectin expression was observed in prasugrel but not in ticagrelor-treated patients (prasugrel early 11.9 ± 9.4% vs. late 26.3 ± 19.0%, P = 0.031, ticagrelor early 9.6 ± 4.9% vs. late 13.5 ± 6.6%, P = 0.127). CONCLUSION: Reticulated platelets show a greater impact on platelet reactivity in response to prasugrel when compared with ticagrelor.

ISAR-SAFE: a randomized, double-blind, placebo-controlled trial of 6 vs. 12 months of clopidogrel therapy after drug-eluting stenting.

BACKGROUND: In patients receiving aspirin, the optimal duration of clopidogrel therapy after drug-eluting stent (DES) implantation remains unclear. METHODS: This multicentre, randomized, double-blind, placebo-controlled trial tested the hypothesis that in patients undergoing DES implantation, 6 months of clopidogrel is non-inferior to 12 months in terms of clinical outcomes. At 6 months after DES implantation, patients on clopidogrel were randomly assigned to either a 6-month period of placebo or an additional 6-month period of clopidogrel. The primary endpoint was the composite of death, myocardial infarction, stent thrombosis, stroke, and thrombolysis in myocardial infarction major bleeding at 9 months after randomization. RESULTS: Owing to slow recruitment and low event rates, the trial was stopped prematurely after enrolment of 4005 of 6000 planned patients. Of 4000 patients included in the final analysis, 1997 received 6 months of clopidogrel and 2003 received 12 months. The primary endpoint occurred in 29 patients (1.5%) assigned to 6 months of clopidogrel and 32 patients (1.6%) assigned to 12 months, observed difference -0.1%, upper limit of one-sided 95% confidence interval (CI) 0.5%, limit of non-inferiority 2%, Pfor noninferiority <0.001. Stent thrombosis was observed in five patients (0.3%) assigned to 6 months of clopidogrel and three patients (0.2%) assigned to 12 months; hazard ratio (HR) 1.66, 95% CI: 0.40-6.96, P = 0.49. Thrombolysis in myocardial infarction major bleeding was observed in 4 patients (0.2%) assigned to 6 months clopidogrel and 5 patients (0.3%) assigned to 12 months; HR 0.80, 95% CI: 0.21-2.98, P = 0.74. CONCLUSIONS: In the present trial, characterized by low event rates, we did not observe a significant difference in net clinical outcome between 6 and 12 months of clopidogrel therapy after DES implantation. However, the results of the trial must be considered in view of its premature termination and lower than expected event rates. The trial is registered with ClinicalTrials.gov, Identifier: NCT00661206.

Prasugrel plus bivalirudin vs. clopidogrel plus heparin in patients with ST-segment elevation myocardial infarction.

AIMS: Whether prasugrel plus bivalirudin is a superior strategy to unfractionated heparin plus clopidogrel in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) has never been assessed in specifically designed randomized trials. METHODS AND RESULTS: The Bavarian Reperfusion Alternatives Evaluation (BRAVE) 4 study is an investigator-initiated, randomized, open-label, multicentre trial, designed to test the hypothesis that in STEMI patients with planned primary PCI a strategy based on prasugrel plus bivalirudin is superior to a strategy based on clopidogrel plus heparin in terms of net clinical outcome. Owing to slow recruitment, the trial was stopped prematurely after enrolment of 548 of 1240 planned patients. At 30 days, the primary composite endpoint of death, myocardial infarction, unplanned revascularization of the infarct related artery, stent thrombosis, stroke, or bleeding was observed in 42 patients (15.6%) randomized to prasugrel plus bivalirudin and 40 patients (14.5%) randomized to clopidogrel plus heparin [relative risk, 1.09; one-sided 97.5% confidence interval (CI) 0-1.79, P = 0.680]. The composite ischaemic endpoint of death, myocardial infarction, unplanned revascularization of the infarct-related artery, stent thrombosis, or stroke occurred in 13 patients (4.8%) in the prasugrel plus bivalirudin group and 15 patients (5.5%) in the clopidogrel plus heparin group (relative risk, 0.89; 95% CI 0.40-1.96, P = 0.894). Bleeding according to the HORIZONS-AMI definition was observed in 38 patients (14.1%) in the prasugrel plus bivalirudin group and 33 patients (12.0%) in the clopidogrel plus heparin group (relative risk, 1.18; 95% CI 0.74-1.88, P = 0.543). Results were consistent across various subgroups of patients. CONCLUSION: In this randomized trial of STEMI patients, we were unable to demonstrate significant differences in net clinical outcome between prasugrel plus bivalirudin and clopidogrel plus heparin. Neither the composite of ischaemic complications nor bleeding were favourably affected by prasugrel plus bivalirudin compared with a regimen of clopidogrel plus unfractionated heparin. However, the results must be interpreted in view of the premature termination of the trial. CLINICAL TRIAL REGISTRATION INFORMATION: Unique identifier NCT00976092 (www.clinicaltrials.gov).

Comparison of vascular closure devices vs manual compression after femoral artery puncture: the ISAR-CLOSURE randomized clinical trial.

IMPORTANCE: The role of vascular closure devices (VCD) for the achievement of hemostasis in patients undergoing transfemoral coronary angiography remains controversial. OBJECTIVE: To compare outcomes with the use of 2 hemostasis strategies after diagnostic coronary angiography performed via transfemoral access-a VCD-based strategy with 2 types of devices, an intravascular device and an extravascular device, vs standard manual compression. The primary hypothesis to be tested was that femoral hemostasis achieved through VCD is noninferior to manual compression in terms of vascular access-site complications. A secondary objective was the comparison of the 2 types of VCD. DESIGN, SETTING, AND PARTICIPANTS: Randomized, large-scale, multicenter, open-label clinical trial. We enrolled 4524 patients undergoing coronary angiography with a 6 French sheath via the common femoral artery from April 2011 through May 2014 in 4 centers in Germany. Last 30-day follow-up was performed in July 2014. INTERVENTIONS: After angiography of the access site, patients were randomized to hemostasis with an intravascular VCD, extravascular VCD, or manual compression in a 1:1:1 ratio. MAIN OUTCOMES AND MEASURES: Primary end point: the composite of access site-related vascular complications at 30 days after randomization with a 2% noninferiority margin. Secondary end points: time to hemostasis, repeat manual compression, and VCD failure. An α-level of .025 was chosen for primary and secondary comparisons. RESULTS: Of the 4524 enrolled patients, 3015 were randomly assigned to a VCD group (1509 received intravascular VCD and 1506 received extravascular VCD) and 1509 patients were randomly assigned to the manual compression group. Before hospital discharge, duplex sonography of the access site was performed in 4231 (94%) patients. The primary end point was observed in 208 patients (6.9%) assigned to receive a VCD and 119 patients (7.9%) assigned to manual compression (difference, -1.0% [1-sided 97.5% CI, 0.7%]; P for noninferiority<.001). Time to hemostasis was significantly shorter in patients with VCD (1 minute [interquartile range {IQR}, 0.5-2.0]), vs manual compression (10 minutes [IQR, 10-15]; P < .001). Time to hemostasis was significantly shorter among patients with intravascular VCD (0.5 minute [IQR, 0.2-1.0]), vs extravascular VCD (2.0 minutes [IQR, 1.0-2.0]; P <.001) and closure device failure was also significantly lower among those with intravascular vs extravascular VCD (80 patients [5.3%], vs 184 patients [12.2%]; P < .001). CONCLUSIONS AND RELEVANCE: In patients undergoing transfemoral coronary angiography, VCDs were noninferior to manual compression in terms of vascular access-site complications and reduced time to hemostasis. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01389375.

A prospective randomized trial comparing the recovery of platelet function after loading dose administration of prasugrel or clopidogrel.

UNLABELLED: Prasugrel results in greater platelet inhibition compared to clopidogrel which may prolong the time to platelet P2Y(12) receptor function recovery following drug cessation after loading dose (LD) administration. This randomized study assessed the time to recovery of platelet function in patients with coronary artery disease after a LD of prasugrel or clopidogrel. Enrolled patients (n = 21) received either prasugrel (30 mg or 60 mg) or clopidogrel (600 mg) in preparation for coronary angiography. Platelet function was assessed by the VerifyNow P2Y12 assay, Multiplate and LTA at baseline and over time (1, 3, 5, 7, 9, and 11 days) post-LD treatment. Recovery of platelet function was defined as occurring on the first day that P2Y12 reaction units were ≤60 below pre-drug values and remained in this range. The relationship between platelet inhibition at 24 h post-LD to time of recovery was also evaluated. Recovery of platelet function occurred from days 3-7 for clopidogrel-treated subjects, by day 7 for patients treated with prasugrel 30 mg and from days 7-9 for patients treated with prasugrel 60 mg. Time for platelet function to return to baseline was independent of treatment assignment, reflecting instead the extent of platelet inhibition at 24 h post-LD (correlation coefficient = 0.81, p < 0.001), which was greater following a prasugrel LD. CONCLUSIONS: Prasugrel-treated subjects require a longer time for recovery compared with clopidogrel due to greater post-LD platelet inhibition. Platelet function testing after cessation of P2Y(12) receptor blockers may prove useful to guide the timing of surgical procedures (clinicaltrials.gov identifier: NCT01107899).

High on-aspirin treatment platelet reactivity and restenosis after percutaneous coronary intervention: results of the Intracoronary Stenting and Antithrombotic Regimen-ASpirin and Platelet Inhibition (ISAR-ASPI) Registry.

OBJECTIVE: The aim of this study was to assess the association between high on-aspirin treatment platelet reactivity (HAPR) and the subsequent risk of restenosis after percutaneous coronary intervention (PCI) with predominantly drug-eluting stents. BACKGROUND: The association between HAPR and subsequent risk of restenosis after PCI is unclear. METHODS: This study included 4839 patients undergoing PCI (02/2007-12/2011) in the setting of the Intracoronary Stenting and Antithrombotic Regimen-ASpirin and Platelet Inhibition (ISAR-ASPI) registry. Platelet function was assessed with impedance aggregometry using the multi-plate analyzer immediately before PCI and after intravenous administration of aspirin (500 mg). The primary outcome was clinical restenosis, defined as target lesion revascularization at 1 year. Secondary outcomes included binary angiographic restenosis and late lumen loss at 6- to 8-month angiography. RESULTS: The upper quintile cut-off of platelet reactivity measurements (191 AU × min) was used to categorize patients into a group with HAPR (platelet reactivity > 191 AU × min; n = 952) and a group without HAPR (platelet reactivity ≤ 191 AU × min; n = 3887). The primary outcome occurred in 94 patients in the HAPR group and 405 patients without HAPR (cumulative incidence, 9.9% and 10.4%; HR = 0.96, 95% CI 0.77-1.19; P = 0.70). Follow-up angiography was performed in 73.2% of patients. There was no difference in binary restenosis (15.2% vs. 14.9%; P = 0.79) or late lumen loss (0.32 ± 0.57 vs. 0.32 ± 0.59 mm; P = 0.93) between patients with HAPR versus those without HAPR. CONCLUSIONS: This study did not find an association between HAPR, measured at the time of PCI, and clinical restenosis at 1 year after PCI.

Efficacy and Safety of Ticagrelor Versus Prasugrel in Women and Men with Acute Coronary Syndrome: A Pre-specified, Sex-Specific Analysis of the ISAR-REACT 5 Trial.

AIM: Sex-specific analyses of direct head-to-head comparisons between newer P2Y12 inhibitors are limited. This study was conducted to assess the efficacy and safety of ticagrelor versus prasugrel in women and men with acute coronary syndromes (ACS) planned for an invasive strategy. METHODS: This pre-specified analysis of the ISAR-REACT 5 trial included 956 women and 3,062 men with ACS randomly assigned to either ticagrelor or prasugrel. The primary endpoint was the 12-month incidence of death, myocardial infarction, or stroke; the safety endpoint was the 12-month incidence of bleeding (type 3-5 according to the Bleeding Academic Research Consortium [BARC]). RESULTS: The primary endpoint occurred in 42 women (8.9%) in the ticagrelor group and 39 women (8.3%) in the prasugrel group (hazard ratio [HR]=1.10, 95% confidence interval [CI] 0.71-1.70, P=0.657) and in 142 men (9.4%) in the ticagrelor group and 98 men (6.5%) in the prasugrel group (HR=1.47 [1.13-1.90], P=0.004; P for interaction [Pint]=0.275). BARC type 3-5 bleeding occurred in 36 women (9.7%) in the ticagrelor group and 34 women (9.7%) in the prasugrel group (HR=1.04 [0.65-1.67], P=0.856) and in 59 men in the ticagrelor group (4.4%) and 46 men (3.6%) in the prasugrel group (HR=1.24 [0.85-1.83], P=0.266; Pint=0.571). CONCLUSIONS: Although there was no significant interaction between sex and treatment effect of study drugs, the superior efficacy of prasugrel was more evident among men. No difference in bleeding between the two study groups was seen for both women and men.

Cytochrome 2C19*17 allelic variant, platelet aggregation, bleeding events, and stent thrombosis in clopidogrel-treated patients with coronary stent placement.

BACKGROUND: The cytochrome P450 (CYP) 2C19 isoenzyme plays an important role in clopidogrel metabolization. A recently explored CYP2C19*17 allelic variant has been linked to increased transcriptional activity, resulting in extensive metabolization of CYP2C19 substrates, which may lead to an enhanced platelet response to clopidogrel treatment. The aim of this study was to assess the impact of CYP2C19*17 on ADP-induced platelet aggregation, the risk of bleeding, and stent thrombosis in clopidogrel-treated patients undergoing percutaneous coronary intervention. METHODS AND RESULTS: The study population included 1524 patients undergoing percutaneous coronary intervention after pretreatment with 600 mg clopidogrel. Genotypes were determined with a TaqMan assay. ADP-induced platelet aggregation was assessed on a Multiplate analyzer. The primary clinical safety end point was the 30-day incidence of bleeding defined according to Thrombolysis in Myocardial Infarction criteria, and the primary clinical efficacy end point was the 30-day incidence of stent thrombosis. For both heterozygous (*wt/*17; n=546) and homozygous (*17/*17; n=76) allele carriers, significantly lower ADP-induced platelet aggregation values were found compared with wild-type homozygotes (*wt/*wt; n=902; P=0.039 and P=0.008, respectively). CYP2C19*17 allele carriage was significantly associated with an increased risk of bleeding; the highest risk was observed for CYP2C19*17 homozygous patients (P=0.01, chi(2) test for trend). Multivariate analysis confirmed the independent association of CYP2C19*17 allele carriage with platelet aggregation values (P<0.001) and the occurrence of bleeding (P=0.006). No significant influence of CYP2C19*17 on the occurrence of stent thrombosis was found (P=0.79). CONCLUSIONS: CYP2C19*17 carrier status is significantly associated with enhanced response to clopidogrel and an increased risk of bleeding.

Lack of impact of calcium-channel blockers on the pharmacodynamic effect and the clinical efficacy of clopidogrel after drug-eluting stenting.

BACKGROUND: Clopidogrel is a prodrug that is metabolized to its active metabolite by the hepatic cytochrome P450 system. Calcium-channel blockers (CCBs) are metabolized by the same pathway and may therefore attenuate the antiplatelet effect of clopidogrel. The aim of this study was to assess the impact of CCB therapy on the pharmacodynamic effect and the clinical efficacy of clopidogrel after drug-eluting stent placement. METHODS: A total of 1,608 consecutive patients were previously enrolled in a study that aimed to assess the relation between platelet reactivity and outcomes after coronary stenting. Here, this cohort was analyzed according to concomitant CCB therapy at admission. The primary pharmacodynamic end point was adenosine diphosphate-induced platelet aggregation (in AU · min) with multiple electrode platelet aggregometry after loading with 600 mg clopidogrel. The primary clinical end point was combination of death or definite stent thrombosis (ST) at 30 days. Secondary end points included definite ST alone, myocardial infarction, stroke, and death. RESULTS: Two hundred thirty-two patients (14.4%) were on CCBs on admission. Compared with patients with CCB medication, patients without CCB medication showed no significant difference in median [interquartile range] platelet aggregation values (232 [142-365] vs 223 [141-368] AU · min, P = .53). There was also no significant difference regarding the clinical end point of death or ST (2 [0.9%] vs 16 [1.2%], odds ratio 0.74, 95% CI 0.17-3.2, P = .69) between both groups. CONCLUSION: In our population, concomitant CCB therapy did not alter clopidogrel-mediated platelet aggregation and did not have a measurable impact on ST and mortality after coronary stenting.

Impact of smoking on antiplatelet effect of clopidogrel and prasugrel after loading dose and on maintenance therapy.

BACKGROUND: Pharmacodynamic studies reported an amplified on-clopidogrel platelet inhibition in smokers potentially caused by an increased metabolic drug activation via induction of cytochrome P450 1A2. The aims of this analysis were to evaluate the impact of smoking on the antiplatelet effect of clopidogrel and prasugrel and to test the potential interaction of smoking with the treatment effect of these drugs. METHODS: A variety of platelet function results was analyzed from 2 large cohorts of patients undergoing coronary intervention after loading with clopidogrel 600 mg (n = 2,533 and n = 1,996), a cohort of patients undergoing dose adaptation from 75 to 150 mg according to response to clopidogrel (n = 117) and a crossover trial comparing clopidogrel 150 mg with prasugrel 10 mg (n = 87). Linear regression analyses were used to test the impact of smoking on platelet function and to identify independent predictors of on-treatment platelet reactivity. The potential interaction of smoking with the clinical effect of clopidogrel versus prasugrel was analyzed in the TRITON-TIMI 38 cohort (n = 13,608). RESULTS: No significant association of smoking with platelet reactivity on clopidogrel was seen in unadjusted and adjusted analyses. The variables most consistently associated with on-clopidogrel platelet function were age, sex, diabetes, and body mass index. There was no significant interaction of smoking status at presentation with the clinical efficacy of prasugrel versus clopidogrel (P for interaction = .39). CONCLUSIONS: Smoking does not impact on platelet reactivity in patients after loading or on different maintenance doses of clopidogrel. The clinical treatment effect of clopidogrel versus prasugrel is not affected by smoking status at presentation.

Oral anticoagulation with coumarin derivatives and antiplatelet effects of clopidogrel.

AIMS: A relevant proportion of patients receiving aspirin and clopidogrel after percutaneous coronary intervention (PCI) also require oral anticoagulation with a coumarin derivative such as phenprocoumon. Both clopidogrel and phenprocoumon are metabolized by the hepatic cytochrome P450 system and a drug-drug interaction may exist at this level. The aim of this study was to investigate the impact of phenprocoumon on the antiplatelet effects of clopidogrel in patients with coronary artery disease. METHODS AND RESULTS: Patients (n = 1223) eligible for this study were under dual maintenance antiplatelet treatment with aspirin and clopidogrel. Adenosine diphosphate-induced platelet aggregation (in AU*min) was measured with multiple electrode platelet aggregometry on a Multiplate analyzer (Dynabyte, Munich, Germany). From the entire study population, 124 (10.1%) patients were under concomitant phenprocoumon treatment at the time point of platelet function testing. Platelet aggregation (median [interquartile range]) was significantly higher in patients with (n = 124) concomitant phenprocoumon treatment compared with patients without (n = 1099) phenprocoumon treatment (308 [190-493] AU*min vs. 224 [145-390] AU*min; P = 0.0001, adjusted P = 0.002). CONCLUSION: Phenprocoumon significantly attenuates the antiplatelet effects of clopidogrel. The impact of this interaction on the risk of thrombotic and bleeding events after PCI requires further investigations.

Comparison of Vascular Closure Devices vs Manual Compression After Femoral Artery Puncture in Patients on Oral Anticoagulation - Post Hoc Analysis of the ISAR-CLOSURE Trial.

OBJECTIVES: To compare vascular closure devices (VCD) with manual compression (MC) in patients on chronic oral anticoagulation (OAC) who undergo diagnostic coronary angiography in terms of vascular access-site complications. METHODS: This is a subanalysis of 604 patients that had undergone transfemoral diagnostic coronary angiography and were randomly assigned to arteriotomy closure with either VCDs (intravascular FemoSeal VCD or extravascular EXOSEAL VCD) or MC within the large scale, randomized ISAR-CLOSURE trial. Primary endpoint was the composite of access-site-related vascular complications at 30 days. Secondary endpoints were time to hemostasis and repeat MC. RESULTS: Vascular access-site complications were similar in patients assigned to VCDs compared to MC (8.2% vs 10.6%; P=.33). There was no interaction of treatment effect and OAC (P interaction = 0.59). Rates of pseudoaneurysms were lower with VCDs (0.8% vs 3.2%; P=.02). Time to hemostasis was significantly shortened with VCDs compared to MC (1 [IQR 0.5-2.0] min vs 12 [IQR 10-15] min; P<.001). There was no difference regarding repeat MC in both groups (VCD 1.5% vs MC 0.5%; P=.23). Time to hemostasis (0.5 [0.2-1.0] min, vs 2.0 [1.75-2.0] min; P<.001) and closure device failure (3.7% vs 17.2%; P<.001) were lower with the intravascular VCD, compared with the extravascular VCD. CONCLUSIONS: In patients on chronic OAC undergoing transfemoral diagnostic coronary angiography, the use of VCDs was comparable to MC regarding the primary combined endpoint of vascular access-site related complications. VCDs reduced the occurrence of pseudoaneurysms and time to hemostasis.

Platelet response to clopidogrel and restenosis in patients treated predominantly with drug-eluting stents.

BACKGROUND: Preclinical studies suggest a relationship between early thrombotic response after vascular injury and later development of restenosis. The aim of this study was to assess the impact of platelet response to clopidogrel on the risk of restenosis after drug-eluting stenting (DES). METHODS: A total of 1,608 consecutive patients were previously enrolled in a study on the relation between platelet reactivity and outcomes after DES. All patients received a loading dose of 600 mg clopidogrel. Blood samples for the assessment of adenosine diphosphate-induced platelet aggregation with multiple electrode platelet aggregometry were drawn directly before percutaneous coronary intervention. Clopidogrel low response was defined as upper quintile of multiple electrode platelet aggregometry measurements. Accordingly, 323 patients (20%) were considered as low and 1,285 (80%) as normal responders. Primary end point of the present study was target lesion revascularization at 1 year. Secondary end points included binary angiographic restenosis and late lumen loss at 6- to 8-month angiography. RESULTS: Target lesion revascularization rates were comparable in both groups (10.9% vs 9.5%, hazard rate [HR] 1.2, 95% CI 0.8-1.7, P = .441). Follow-up angiography revealed no difference in binary angiographic restenosis (13.9% vs 15.9%, P = .445) and late lumen loss (0.32 +/- 0.64 vs 0.35 +/- 0.63 mm, P = .477). Low responders had significantly more stent thromboses (2.5% vs 0.5%, HR 5.4, 95% CI 1.9-15.6, P = .002), Q wave myocardial infarctions (2.5% vs 0.6%, HR 4.0, 95% CI 1.5-10.7, P = .005), and ischemic strokes (1.3% vs 0.2%, HR 5.4, 95% CI 1.2-24.0, P = .028) at 1 year. CONCLUSION: Low platelet responsiveness to clopidogrel, a known predictor of thrombotic complications, does not have a significant impact on restenosis after DES.

Cytochrome P450 2C19 loss-of-function polymorphism and stent thrombosis following percutaneous coronary intervention.

AIMS: Several studies have demonstrated that the mutant *2 allele of the CYP2C19 681G>A loss-of-function polymorphism is associated with diminished metabolization of clopidogrel into its active thiol metabolite and an attenuated platelet response to clopidogrel treatment. It is not known whether patients carrying the mutant CYP2C19*2 allele have a higher risk of stent thrombosis (ST) compared with homozygous CYP2C19*1 wild-type allele carriers following percutaneous coronary intervention (PCI). The aim of this study was to assess the impact of the CYP2C19 681G>A loss-of-function polymorphism on ST following PCI performed after pre-treatment with clopidogrel. METHODS AND RESULTS: The study population included 2485 consecutive patients undergoing coronary stent placement after pre-treatment with 600 mg of clopidogrel. Genotypes were determined with a TaqMan assay. The primary endpoint of the study was the incidence of definite ST within 30 days following PCI. Of the patients studied, 1805 (73%) were CYP2C19 wild-type homozygotes (*1/*1) and 680 (27%) carried at least one *2 allele (*1/*2 or *2/*2). The cumulative 30-day incidence of ST was significantly higher in CYP2C19*2 allele carriers (*1/*2 or *2/*2) vs. CYP2C19 wild-type homozygotes (*1/*1) [10 patients (1.5%) in CYP2C19*2 allele carriers vs. 7 (0.4%) in CYP2C19 wild-type homozygotes (*1/*1), HR 3.81, 95% CI 1.45-10.02, P = 0.007; P = 0.006 after adjustment for confounding variables]. The risk of ST was highest (2.1%) in patients with the CYP2C19 *2/*2 genotype (P = 0.002). CONCLUSION: CYP2C19*2 carrier status is significantly associated with an increased risk of ST following coronary stent placement.

Impact of proton pump inhibitors on the antiplatelet effects of clopidogrel.

Patients receiving dual antiplatelet treatment with aspirin and clopidogrel are commonly treated with proton pump inhibitors (PPIs). Attenuating effects on platelet response to clopidogrel have been reported solely for the PPI omeprazole. PPIs differ in their metabolisation properties as well as their potential for drug-drug interactions. The aim of this study was to investigate the impact of different PPIs (pantoprazole, omeprazole, esomeprazole) on platelet response to clopidogrel in patients with previous coronary stent placement under chronic clopidogrel treatment. In a cross-sectional observational study, consecutive patients under clopidogrel maintenance treatment (n = 1,000) scheduled for a control coronary angiography were enrolled. Adenosine diphosphate (ADP)-induced platelet aggregation (in AU*min) was measured with multiple electrode platelet aggregometry (MEA). From the entire study population, 268 (26.8%) patients were under PPI treatment at the time point of platelet function testing (pantoprazole, n = 162; omeprazole, n = 64; esomeprazole, n = 42). Platelet aggregation (median [interquartile range]) was significantly higher in patients with omeprazole treatment (295.5 [193.5-571.2] AU*min) compared to patients without PPI treatment (220.0 [143.8-388.8] AU*min; p = 0.001). Platelet aggregation was similar in patients with pantoprazole (226.0 [150.0-401.5] AU*min) or esomeprazole (209.0 [134.8-384.8] AU*min) treatment compared to patients without PPI treatment (p = 0.69 and p = 0.88, respectively). Attenuating effects of concomitant PPI treatment on platelet response to clopidogrel were restricted to the use of omeprazole. No attenuating effects on platelet response to clopidogrel were observed for pantoprazole or esomeprazole. Specifically designed and randomized clinical studies are needed to define the impact of concomitant PPI treatment on adverse events after percutaneous coronary intervention.

Comparison of Vascular Closure Devices Versus Manual Compression After Femoral Artery Puncture in Women.

BACKGROUND: The value of vascular closure devices (VCD) in women undergoing transfemoral catheterization has not been sufficiently investigated. METHODS AND RESULTS: This is a sex-specific analysis of 1395 women enrolled in a large-scale, randomized, multicenter trial, in which patients undergoing transfemoral diagnostic coronary angiography were randomly assigned in a 1:1:1 ratio to arteriotomy closure with an intravascular VCD, extravascular VCD, or manual compression (MC). Primary objective was to assess the safety and efficacy of 2 different VCD compared with MC regarding vascular access-site complications at 30 days. A secondary comparison was between 2 different types of contemporary VCD. Overall, women were at higher risk for vascular access-site complications compared with men (9.0% versus 6.4%; P=0.002). Vascular access-site complications were comparable in women assigned to VCD and MC (8.6% versus 9.8%; P=0.451). There was no interaction of treatment effect and sex ( Pinteraction=0.970). Time to hemostasis was significantly shortened with VCD compared with MC (1 [interquartile range, 0.5-2.0] minutes) versus 11 [interquartile range, 10-15] minutes; P<0.001); however, more women with VCD required repeat MC (2.4% versus 0.6%; P=0.018). The use of the intravascular compared with the extravascular VCD was associated with a numerical reduction in vascular access-site complications (6.6% versus 10.7%; P=0.027) and significant reductions in time to hemostasis and VCD failure. CONCLUSIONS: In women undergoing diagnostic coronary angiography via the common femoral artery, VCD and MC provided comparable safety, while time to hemostasis was reduced with VCD. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT01389375.

Validation of the DAPT score in patients randomized to 6 or 12 months clopidogrel after predominantly second-generation drug-eluting stents.

The DAPT score is a recently-proposed decision tool for guiding optimal duration of dual antiplatelet therapy (DAPT). It showed modest accuracy in prior derivation and validation cohorts of patients with ≥12 months DAPT. This study was aimed to evaluate the validity of the DAPT score in a cohort of patients with 6 or 12 months DAPT after implantation of predominantly second-generation drug-eluting stents. We analyzed data of patients enrolled in the ISAR-SAFE trial. Patients were classified into low (<2) or high (≥2) DAPT score groups. Primary ischaemic (all-cause death, myocardial infarction, definite stent thrombosis or stroke) and bleeding (TIMI major or minor) outcomes were analyzed in the low and high DAPT score groups. Data of 3976 patients were available for DAPT score calculation. 2407 patients (60.5 %) were classified in the low DAPT score group and 1569 patients (39.5 %) in the high DAPT score group. In the low DAPT score group there were no significant differences between 6 and 12 months DAPT regarding ischaemic (1.0 % vs. 1.4 %, HR=0.74, 95 % CI, 0.35-1.57; p=0.43) or bleeding outcomes (0.3 % vs. 0.8 %, HR=0.44, 95 % CI, 0.13-1.42; p=0.17). In the high DAPT score group there were also no significant differences between 6 and 12 months DAPT regarding ischaemic (1.9 % vs. 1.8 %, HR=1.02, 95 % CI, 0.49-2.14; p=0.96) or bleeding (0.3 % vs. 0.5 %, HR=0.51, 95 % CI, 0.09-2.78; p=0.44) outcomes. In conclusion, the DAPT score failed to show a differential treatment effect in patients receiving 6 or 12 months DAPT after contemporary drug-eluting stent implantation.

Six Versus Twelve Months Clopidogrel Therapy After Drug-Eluting Stenting in Patients With Acute Coronary Syndrome: An ISAR-SAFE Study Subgroup Analysis.

In patients presenting with acute coronary syndrome (ACS) the optimal duration of dual-antiplatelet therapy after drug-eluting stent (DES) implantation remains unclear. At 6 months after intervention, patients receiving clopidogrel were randomly assigned to either a further 6-month period of placebo or clopidogrel. The primary composite endpoint was death, myocardial infarction, stent thrombosis, stroke, or major bleeding 9 months after randomization. The ISAR-SAFE trial was terminated early due to low event rates and slow recruitment. 1601/4000 (40.0%) patients presented with ACS and were randomized to 6 (n = 794) or 12 months (n = 807) clopidogrel. The primary endpoint occurred in 14 patients (1.8%) receiving 6 months of clopidogrel and 17 patients (2.2%) receiving 12 months; hazard ratio (HR) 0.83, 95% confidence interval (CI) 0.41-1.68, P = 0.60. There were 2 (0.3%) cases of stent thrombosis in each group; HR 1.00, 95% CI 0.14-7.09, P = >0.99. Major bleeding occurred in 3 patients (0.4%) receiving 6 months clopidogrel and 5 (0.6%) receiving 12 months; HR 0.60, 95% CI 0.15-2.49, P = 0.49. There was no significant difference in net clinical outcomes after DES implantation in ACS patients treated with 6 versus 12 months clopidogrel. Ischaemic and bleeding events were low beyond 6-months.