Incidence, predictors and impact of stroke on mortality among patients with acute coronary syndromes following percutaneous coronary intervention-Results from the PROMETHEUS registry.

BACKGROUND: Stroke represents a potentially calamitous complication among patients with acute coronary syndrome (ACS) undergoing percutaneous intervention (PCI). Data on the distribution of stroke occurrence post-PCI and its impact on mortality are scarce. OBJECTIVES: We sought to determine the incidence, predictors and impact of stroke on mortality in ACS patients undergoing PCI. METHODS: A total of 19,914 ACS patients underwent PCI in the PROMETHEUS multicenter observational study. We calculated the cumulative stroke incidence at 30 days and 1 year using the Kaplan Meier method. We also compared the distribution of stroke, myocardial infarction (MI), and bleeding across time and evaluated their overlap. Predictors of stroke were identified through multivariable Cox-regression. Stroke, MI, and bleeding were assessed as time-updated covariates to estimate how each impacts subsequent mortality. RESULTS: We found that 244 patients had a stroke within 1 year, a cumulative incidence of 1.5%. Previous cerebrovascular disease was the strongest predictor for post-PCI stroke, followed by ST-elevation MI presentation, hypertension, non-ST-elevation MI presentation, smoking, female sex, and age. Mortality risk was significantly higher among those who had a stroke versus those who did not (adjusted HR 4.84, p < .0001). However, the association attenuated over time with a much larger effect in the first 30 days of its occurrence (adjusted HR 17.7; 95% CI: 12.3-25.4, p < .0001) versus beyond 30 days (adjusted HR 1.22; 95% CI: 0.6-2.46, p = .58). CONCLUSIONS: Stroke occurrence within 1 year was not uncommon for ACS patients undergoing PCI. When compared with MI and bleeding, stroke had a substantial impact on mortality that attenuated rapidly over time.

The prevalence, predictors and outcomes of guideline-directed medical therapy in patients with acute myocardial infarction undergoing PCI, an analysis from the PROMETHEUS registry.

OBJECTIVES: To investigate the prevalence, predictors and associations between guideline-directed medical therapy (GDMT) and clinical outcomes in acute myocardial infarction (AMI) patients undergoing percutaneous coronary intervention (PCI) from eight academic centers in the United States. BACKGROUND: Evidence for GDMT in patients with AMI comes from randomized controlled trials. The use of GDMT in clinical practice is unknown in this setting. METHODS: PROMETHEUS is a multicenter observational registry comprising 19,914 patients with acute coronary syndrome (ACS) undergoing PCI. Patients with AMI were divided into two groups based on the prescription of GDMT or not (non-GDMT) at discharge. GDMT was defined according to American College of Cardiology/American Heart Association (ACC/AHA) class I recommendations, specifically, dual antiplatelet therapy, statin and beta-blocker for all AMI patients, and additional ACEI/ARB in patients with left ventricular ejection fraction (LVEF) less than 40%, hypertension, diabetes mellitus (DM) or chronic kidney disease (CKD). The primary endpoint was major adverse cardiovascular events (MACE) defined as a composite of all-cause death, MI, stroke or unplanned target vessel revascularization (TVR) at 1 year. RESULTS: Out of 4,834 patients with AMI, 3,356 (69.4%) patients were discharged on GDMT. Patients receiving GDMT were more often younger and male. Compared with non-GDMT patients, GDMT patients had a significantly lower frequency of comorbidities. Predictors of greater GDMT prescription at discharge were ST-segment elevation myocardial infarction (STEMI), and increased body mass index (BMI), whereas hypertension, prior PCI, anemia and CKD were associated with less GDMT prescription. At 1 year, the use of GDMT was associated with a significantly lower incidence of MACE (13.7% vs. 22.5%; adjusted HR 0.68; 95%CI 0.58-0.80; P < 0.001), death (3.7% vs. 9.4%; adjusted HR 0.61; 95%CI 0.46-0.80; P < 0.001), and unplanned TVR (8.4% vs. 11.3%; adjusted HR 0.76; 95%CI 0.61-0.96; P = 0.020). However, there were no significant differences in the incidence of MI (4.3% vs. 7.0%; adjusted HR 0.75; 95%CI 0.56-1.01; P = 0.056), stroke (1.5% vs. 2.0%; adjusted HR 0.79; 95%CI 0.47-1.34; P = 0.384) between the two groups. CONCLUSION: In a contemporary practice setting in the United States, GDMT was utilized in just over two-thirds of AMI patients undergoing PCI. Predictors of GDMT prescription at discharge included STEMI, BMI and absence of hypertension, CKD, anemia or prior PCI. Use of GDMT was associated with significantly lower risk of 1-year MACE and mortality.

The safety and effectiveness of adenosine diphosphate receptor inhibitor pretreatment among acute myocardial infarction patients treated with percutaneous coronary intervention in community practice: Insights from the TRANSLATE-ACS study.

OBJECTIVES: To understand the optimal timing of adenosine diphosphate (ADP) receptor inhibitor pretreatment prior to percutaneous coronary intervention (PCI) among acute myocardial infarction (MI) patients. BACKGROUND: The role of ADP receptor inhibitor pretreatment in this population is unclear. METHODS: A total of 9,251 ADP receptor inhibitor-naïve MI patients undergoing PCI at 229 TRANSLATE-ACS sites were evaluated. Adjusted risks of in-hospital major adverse cardiovascular events (MACE) and major bleeding were compared among patients with and without pretreatment using inverse probability-weighted propensity adjustment. RESULTS: Of 9,251 patients treated with either prasugrel or clopidogrel during the index MI hospitalization, 4,056 (44%) received pretreatment (ST-segment elevation MI [STEMI] 54.9%, non-STEMI 45.1%); pretreatment was used more commonly among those receiving clopidogrel than prasugrel (52% vs. 20%, P < 0.0001). MACE risks were not significantly different between patients with and without pretreatment (clopidogrel 2.1% vs. 2.2%, adjusted hazard ratio [HR] 1.00, 95% confidence interval [CI] 0.70-1.43; prasugrel 2.1% vs. 2.3%, adjusted odds ratio [OR] 0.82, 95% CI 0.42-1.60). No differences in major bleeding were observed among those receiving versus not receiving pretreatment (clopidogrel 3.1% vs. 3.5%, adjusted HR 0.94, 95% CI 0.65-1.36; prasugrel 2.5% vs. 2.7%, adjusted OR 0.93, 95% CI 0.42-2.02); results were similar when stratified by MI type. CONCLUSIONS: ADP receptor inhibitor pretreatment (44%) is commonly used among acute MI patients undergoing PCI in contemporary practice, but no significant differences were found in in-hospital MACE and/or bleeding risks between patients receiving versus not receiving pretreatment, regardless of ADP receptor inhibitor type.

Use of prasugrel vs clopidogrel and outcomes in patients with acute coronary syndrome undergoing percutaneous coronary intervention in contemporary clinical practice: Results from the PROMETHEUS study.

BACKGROUND AND OBJECTIVES: We sought to determine the frequency of use and association between prasugrel and outcomes in acute coronary syndrome patients undergoing percutaneous coronary intervention (PCI) in clinical practice. METHODS: PROMETHEUS was a multicenter observational registry of acute coronary syndrome patients undergoing PCI from 8 centers in the United States that maintained a prospective PCI registry for patient outcomes. The primary end points were major adverse cardiovascular events at 90days, a composite of all-cause death, nonfatal myocardial infarction, stroke, or unplanned revascularization. Major bleeding was defined as any bleeding requiring hospitalization or blood transfusion. Hazard ratios (HRs) were generated using multivariable Cox regression and stratified by the propensity to treat with prasugrel. RESULTS: Of 19,914 patients (mean age 64.4years, 32% female), 4,058 received prasugrel (20%) and 15,856 received clopidogrel (80%). Prasugrel-treated patients were younger with fewer comorbid risk factors compared with their counterparts receiving clopidogrel. At 90days, there was a significant association between prasugrel use and lower major adverse cardiovascular event (5.7% vs 9.6%, HR 0.58, 95% CI 0.50-0.67, P<.0001) and bleeding (1.9% vs 2.9%, HR 0.65, 95% CI 0.51-0.83, P<.001). After propensity stratification, associations were attenuated and no longer significant for either outcome. Results remained consistent using different approaches to adjusting for potential confounders. CONCLUSIONS: In contemporary clinical practice, patients receiving prasugrel tend to have a lower-risk profile compared with those receiving clopidogrel. The lower ischemic and bleeding events associated with prasugrel use were no longer evident after accounting for these baseline differences.

Switching of adenosine diphosphate receptor inhibitor after hospital discharge among myocardial infarction patients: Insights from the Treatment with Adenosine Diphosphate Receptor Inhibitors: Longitudinal Assessment of Treatment Patterns and Events after Acute Coronary Syndrome (TRANSLATE-ACS) observational study.

The reasons for postdischarge adenosine diphosphate receptor inhibitor (ADPri) switching among patients with myocardial infarction (MI) are unclear. We sought to describe the incidence and patterns of postdischarge ADPri switching among patients with acute MI treated with percutaneous coronary intervention. METHODS: We used TRANSLATE-ACS (2010-2012) data to assess postdischarge ADPri switching among 8,672 MI patients discharged after percutaneous coronary intervention who remained on ADPri therapy 1 year post-MI. We examined patient-reported reasons for switching, GUSTO moderate or severe bleeding, major adverse cardiovascular events (MACEs), and definite stent thrombosis events around the time of the switch. RESULTS: Among patients still on ADPri therapy 1 year post-MI, 663 (7.6%) switched ADPri during that year. Switching occurred at a median of 50 days postdischarge and most frequently in patients discharged on ticagrelor (64/226; 28.3%), followed by prasugrel (383/2,489; 15.4%) and clopidogrel (216/5,957; 3.6%) (P < .001). Among patients discharged on prasugrel, 97.3% of switches were to clopidogrel and 87.5% of ticagrelor switches were to clopidogrel; both of these groups most often cited cost as a reason for switching (43.6% and 39.1%, respectively), whereas 60.7% who switched from clopidogrel cited physician decision as a reason. In the 7 days preceding the switch from clopidogrel, 40 (18.5%) had a MACE and 12 (5.6%) had a definite stent thrombosis event, whereas that from prasugrel or ticagrelor, a GUSTO moderate or severe bleeding event occurred in 1 (0.3%) and 0 patients, respectively. CONCLUSIONS: Postdischarge ADPri switching occurred infrequently within the first year post-MI and uncommonly was associated with MACEs or bleeding events.

Impact of Proton Pump Inhibitor Use on the Comparative Effectiveness and Safety of Prasugrel Versus Clopidogrel: Insights From the Treatment With Adenosine Diphosphate Receptor Inhibitors: Longitudinal Assessment of Treatment Patterns and Events After Acute Coronary Syndrome (TRANSLATE-ACS) Study.

BACKGROUND: Proton pump inhibitors (PPIs) reduce gastrointestinal bleeding events but may alter clopidogrel metabolism. We sought to understand the comparative effectiveness and safety of prasugrel versus clopidogrel in the context of proton pump inhibitor (PPI) use. METHODS AND RESULTS: Using data on 11 955 acute myocardial infarction (MI) patients treated with percutaneous coronary intervention at 233 hospitals and enrolled in the TRANSLATE-ACS study, we compared whether discharge PPI use altered the association of 1-year adjusted risks of major adverse cardiovascular events (MACE; death, MI, stroke, or unplanned revascularization) and Global Use of Strategies To Open Occluded Arteries (GUSTO) moderate/severe bleeding between prasugrel- and clopidogrel-treated patients. Overall, 17% of prasugrel-treated and 19% of clopidogrel-treated patients received a PPI at hospital discharge. At 1 year, patients discharged on a PPI versus no PPI had higher risks of MACE (adjusted hazard ratio [HR] 1.38, 95% confidence interval [CI] 1.21-1.58) and GUSTO moderate/severe bleeding (adjusted HR 1.55, 95% CI 1.15-2.09). Risk of MACE was similar between prasugrel and clopidogrel regardless of PPI use (adjusted HR 0.88, 95% CI 0.62-1.26 with PPI, adjusted HR 1.07, 95% CI 0.90-1.28 without PPI, interaction P=0.31). Comparative bleeding risk associated with prasugrel versus clopidogrel use differed based on PPI use but did not reach statistical significance (adjusted HR 0.73, 95% CI 0.36-1.48 with PPI, adjusted HR 1.34, 95% CI 0.79-2.27 without PPI, interaction P=0.17). CONCLUSIONS: PPIs did not significantly affect the MACE and bleeding risk associated with prasugrel use, relative to clopidogrel. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01088503.

Early Cessation of Adenosine Diphosphate Receptor Inhibitors Among Acute Myocardial Infarction Patients Treated With Percutaneous Coronary Intervention: Insights From the TRANSLATE-ACS Study (Treatment With Adenosine Diphosphate Receptor Inhibitors: Longitudinal Assessment of Treatment Patterns and Events After Acute Coronary Syndrome).

BACKGROUND: Guidelines recommend the use of adenosine diphosphate receptor inhibitor (ADPri) therapy for 1 year postacute myocardial infarction; yet, early cessation of therapy occurs frequently in clinical practice. METHODS AND RESULTS: We examined 11 858 acute myocardial infarction patients treated with percutaneous coronary intervention discharged alive on ADPri therapy from 233 United States TRANSLATE-ACS study (Treatment With Adenosine Diphosphate Receptor Inhibitors: Longitudinal Assessment of Treatment Patterns and Events After Acute Coronary Syndrome) participating hospitals to determine the prevalence of early ADPri cessation (within 1 year), patient-reported reasons for cessation, and associated risk of major adverse cardiovascular events at 1 year. Overall, 2514 (21.2%) of percutaneous coronary intervention-treated patients stopped ADPri by 1 year postmyocardial infarction; the median time from discharge to cessation was 200.5 days (25th, 75th percentiles: 71, 340). Among those with early ADPri cessation, 53.9% received drug-eluting stents and had a median duration of 301 treatment days (25th, 75th percentiles: 137, 353); 33.3% of drug-eluting stent patients stopped treatment within 6 months compared with 64.2% of bare metal stent patients. Those discharged on prasugrel (versus clopidogrel) had a slightly higher likelihood of early ADPri cessation (23.2% versus 21.0%; P=0.03; adjusted hazard ratio, 1.28; 95% confidence interval, 1.17-1.40). Patient-reported reasons for early ADPri cessation included physician-recommended discontinuation (54%), as well as patient self-discontinuation, because of cost (19%), medication side effects (9%), and procedural interruption (10%). Using a time-dependent covariate model, early cessation of ADPri therapy was associated with increased major adverse cardiovascular event (adjusted hazard ratio, 1.40; 95% confidence interval, 1.19-1.65; P<0.0001). CONCLUSIONS: One in 5 percutaneous coronary intervention-treated myocardial infarction patients stopped ADPri treatment within 1 year. Early cessation was associated with increased major adverse cardiovascular event risk. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01088503.

Contemporary use of platelet function and pharmacogenomic testing among patients with acute myocardial infarction undergoing percutaneous coronary intervention in the United States.

BACKGROUND: Although platelet function and pharmacogenomic testing have been studied in clinical trials, their adoption into contemporary practice is unknown. METHODS: We studied patterns of platelet function and pharmacogenomic testing among 10,048 patients with acute myocardial infarction treated with percutaneous coronary intervention at 226 US hospitals in the TRANSLATE-ACS observational study between April 2010 and October 2012, excluding those receiving research protocol-mandated testing. Inverse probability-weighted propensity adjustment was used to compare 1-year bleeding and major adverse cardiac event risks between patients with and without testing. RESULTS: Overall, 337 (3.4%) patients underwent predischarge platelet function testing, whereas 85 (0.9%) underwent pharmacogenomic testing; 82% and 93% of hospitals never performed any platelet function or pharmacogenomic testing, respectively. Patients undergoing testing were more likely to be on an adenosine diphosphate receptor inhibitor preadmission or to have percutaneous coronary intervention of a previously treated lesion. Tested patients were more likely than nontested patients to be switched from clopidogrel to prasugrel/ticagrelor (25.7% vs 9.7%, P < .001) and were more likely to be on prasugrel/ticagrelor 6 months postdischarge (33.8% vs 25.1%, P < .001). No significant differences in 1-year bleeding and major adverse cardiac event risks were observed between tested and nontested patients (adjusted hazard ratios 1.06 [95% CI 0.68-1.65] and 1.21 [95% CI 0.94-1.54], respectively). CONCLUSIONS: Platelet function and pharmacogenomic testing are rarely performed in contemporary myocardial infarction patients in the United States. When tested, patients were more likely to be treated with higher-potency adenosine diphosphate receptor inhibitors, yet no significant differences in longitudinal outcomes were observed.

Association of Discharge Aspirin Dose With Outcomes After Acute Myocardial Infarction: Insights From the Treatment with ADP Receptor Inhibitors: Longitudinal Assessment of Treatment Patterns and Events after Acute Coronary Syndrome (TRANSLATE-ACS) Study.

BACKGROUND: Aspirin is the most widely used antiplatelet drug postmyocardial infarction, yet its optimal maintenance dose after percutaneous coronary intervention with stenting remains uncertain. METHODS AND RESULTS: We compared outcomes of 10 213 patients with myocardial infarction who underwent percutaneous coronary intervention and were discharged on dual-antiplatelet therapy at 228 US hospitals in the Treatment with ADP Receptor Inhibitors: Longitudinal Assessment of Treatment Patterns and Events after Acute Coronary Syndrome (TRANSLATE-ACS) study from 2010 to 2012. Major adverse cardiovascular events and bleeding within 6 months postdischarge were compared between high-dose (325 mg) and low-dose aspirin (81 mg) by using regression models with inverse probability-weighted propensity adjustment. Overall, 6387 patients (63%) received high-dose aspirin at discharge. Major adverse cardiovascular events risk was not significantly different between groups (high versus low: unadjusted 8.2% versus 9.2%; adjusted hazard ratio, 0.99; 95% confidence interval, 0.85-1.17). High-dose aspirin use was associated with greater risk of any Bleeding Academic Research Consortium-defined bleeding events (unadjusted 24.2% versus 22.7%; adjusted odds ratio, 1.19; 95% confidence interval, 1.06-1.33), driven mostly by minor Bleeding Academic Research Consortium type 1 or 2 bleeding events not requiring hospitalization (unadjusted 21.4% versus 19.5%; adjusted odds ratio, 1.19; 95% confidence interval, 1.05-1.34). Bleeding events requiring hospitalization were similar by aspirin dosing groups (unadjusted 2.8% versus 3.2%, adjusted odds ratio, 1.22; 95% confidence interval, 0.87-1.70). Similar associations were observed in landmark analyses accounting for aspirin dosing change over time, and across subgroup analyses by age, sex, baseline aspirin use, and type of ADP receptor inhibitor (clopidogrel versus prasugrel/ticagrelor). CONCLUSIONS: Among percutaneous coronary intervention-treated patients with myocardial infarction, high-maintenance-dose aspirin was associated with similar rates of major adverse cardiovascular events, but a greater risk of minor bleeding than those discharged on low-dose aspirin.

Cluster-randomized clinical trial examining the impact of platelet function testing on practice: the treatment with adenosine diphosphate receptor inhibitors: longitudinal assessment of treatment patterns and events after acute coronary syndrome prospective open label antiplatelet therapy study.

BACKGROUND: Little is known about how clinicians use platelet function testing to guide choice and dosing of adenosine diphosphate receptor inhibitor (ADPri) therapy in routine community practice. METHODS AND RESULTS: The Treatment With Adenosine Diphosphate Receptor Inhibitors: Longitudinal Assessment of Treatment Patterns and Events After Acute Coronary Syndrome (ACS)-Prospective, Open Label, Antiplatelet Therapy Study (TRANSLATE-POPS) was a cluster-randomized trial in which 100 hospitals were assigned access to no-cost platelet function testing versus usual care for acute myocardial infarction patients treated with percutaneous coronary intervention. In both arms, ADPri treatment decisions were left up to the care team. The primary end point was the frequency of ADPri therapy adjustment before discharge. Secondary end points included 30-day rates of major adverse cardiovascular events and Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries-defined bleeding events. Platelet function testing was performed in 66.9% of patients treated in intervention sites versus 1.4% of patients in usual care sites. Intervention arm patients were more likely to have ADPri therapy adjustment than usual care patients (14.8% versus 10.5%, P=0.004; odds ratio 1.68, 95% confidence interval 1.18-2.40); however, there were no significant differences in 30-day major adverse cardiovascular events (4.8% versus 5.4%, P=0.73; odds ratio 0.94, 95% confidence interval 0.66-1.34) or bleeding (4.3% versus 4.2%, P=0.33; odds ratio 0.86, 95% confidence interval 0.55-1.34). One-year outcomes were also not significantly different between groups. An as-treated analysis showed higher incidence of ADPri therapy adjustment among intervention arm patients who received platelet function testing than untested usual care arm (16.4% versus 10.2%, P<0.0001), but no significant differences in major adverse cardiovascular events or bleeding. CONCLUSIONS: TRANSLATE-POPS found that when clinicians routinely used platelet function testing, they were more likely to adjust their choice or dosing of ADPri therapy; yet with few changes in therapy overall, significant differences in clinical outcomes were not seen. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01088503.

Outcomes of Patients With Acute Myocardial Infarction Undergoing Percutaneous Coronary Intervention Receiving an Oral Anticoagulant and Dual Antiplatelet Therapy: A Comparison of Clopidogrel Versus Prasugrel From the TRANSLATE-ACS Study.

OBJECTIVES: The purpose of this study was to determine whether bleeding risk varies depending on which P2Y12 receptor inhibitor agent is used. BACKGROUND: Prior studies have shown significant bleeding risk among patients treated with triple therapy (i.e., oral anticoagulant, P2Y12 receptor inhibitor, and aspirin). METHODS: We evaluated patients with acute myocardial infarction (MI) treated with percutaneous coronary intervention (PCI) at 233 hospitals in the United States enrolled in the TRANSLATE-ACS (Treatment with Adenosine Diphosphate Receptor Inhibitors: Longitudinal Assessment of Treatment Patterns and Events After Acute Coronary Syndrome) study (April 2010 to October 2012). Using inverse probability-weighted propensity modeling, we compared 6-month adjusted risks of Bleeding Academic Research Consortium (BARC) bleeding, stratifying by whether or not bleeding was associated with rehospitalization among patients discharged on aspirin + anticoagulant + clopidogrel (triple-C), aspirin + anticoagulant + prasugrel (triple-P), aspirin + clopidogrel (dual-C), or aspirin + prasugrel (dual-P). RESULTS: Of 11,756 MI patients, 526 (4.5%) were discharged on triple-C, 91 (0.8%) on triple-P, 7,715 (66%) on dual-C, and 3,424 (29%) on dual-P. Compared with dual-therapy patients, triple-therapy patients had significantly higher any BARC-defined bleeding. Triple-P was associated with a greater risk of any BARC-defined bleeding events compared with triple-C. This finding was driven mostly by an increased risk of bleeding events that were patient-reported only and did not require rehospitalization. There were no significant differences in bleeding requiring rehospitalization between the triple-P and -C groups. CONCLUSIONS: Among MI patients, the addition of an oral anticoagulant was associated with a significantly greater risk of any BARC-defined bleeding relative to dual antiplatelet therapy, regardless of which P2Y12 receptor inhibitor was selected. Among patients on triple therapy, prasugrel use was associated with higher patient-reported-only bleeding, but not bleeding requiring rehospitalization, than clopidogrel-treated patients.

Thienopyridine efficacy and cigarette smoking status.

Dual antiplatelet therapy with aspirin and a P2Y12 receptor blocker is an established regimen to reduce the risk of ischemic event occurrence in patients with high-risk cardiovascular (CV) disease. Cigarette smoking is an important cardiovascular risk factor. However, several investigators have reported what may be termed a "new" "smoker's paradox", whereby clopidogrel-treated nonsmokers appear to have either less or no CV-event reduction when compared to the substantial CV-event reduction in clopidogrel-treated smokers based on several large-scale trials. This "smoker's paradox" observed in multiple clinical outcome studies is also supported by emerging "real-world" data that also suggest clopidogrel nonsmokers do not fare as well as smokers treated with clopidogrel. In support of the new "smoker's paradox", pharmacodynamic studies have also shown that smoking status influences clopidogrel responsiveness in healthy volunteers, acute coronary syndrome patients, and patients treated with percutaneous coronary intervention. Finally, there is a substantial, albeit not entirely consistent, body of pharmacodynamic and clinical outcome data supporting a reduced antiplatelet effect of clopidogrel in non-smokers as compared to smokers. The clinical relevance of this interaction has never been demonstrated in a prospective trial. The focus of this review is to critically evaluate the reported interaction between cigarette smoking status and thienopyridine efficacy.

The influence of smoking status on the pharmacokinetics and pharmacodynamics of clopidogrel and prasugrel: the PARADOX study.

OBJECTIVES: The goal of this study was to evaluate the effect of smoking on the pharmacokinetics and pharmacodynamics (PD) of clopidogrel and prasugrel therapy. BACKGROUND: Major randomized trial data demonstrated that nonsmokers experience less or no benefit from clopidogrel treatment compared with smokers (i.e., the "smokers' paradox"). METHODS: PARADOX was a prospective, randomized, double-blind, double-dummy, placebo-controlled, crossover study of objectively assessed nonsmokers (n = 56) and smokers (n = 54) with stable coronary artery disease receiving aspirin therapy. Patients were randomized to receive clopidogrel (75 mg daily) or prasugrel (10 mg daily) for 10 days and crossed over after a 14-day washout. PD was assessed by using VerifyNow P2Y12 and vasodilator-stimulated phosphoprotein phosphorylation assays. Clopidogrel and prasugrel metabolite levels, cytochrome P450 1A2 activity, CYP2C19 genotype, and safety parameters were determined. RESULTS: During clopidogrel therapy, device-reported inhibition of platelet aggregation (IPA) trended lower in nonsmokers than smokers (least squares mean treatment difference ± SE: 7.7 ± 4.1%; p = 0.062). Device-reported IPA was significantly lower in clopidogrel-treated smokers than prasugrel-treated smokers (least squares mean treatment difference: 31.8 ± 3.4%; p < 0.0001). During clopidogrel therapy, calculated IPA was lower and P2Y12 reaction units and vasodilator-stimulated phosphoprotein phosphorylation and platelet reactivity index were higher in nonsmokers than in smokers (p = 0.043, p = 0.005, and p = 0.042, respectively). Greater antiplatelet effects were present after prasugrel treatment regardless of smoking status (p < 0.001 for all comparisons). CONCLUSIONS: PARADOX demonstrated lower clopidogrel active metabolite exposure and PD effects of clopidogrel in nonsmokers relative to smokers. Prasugrel was associated with greater active metabolite exposure and PD effects than clopidogrel regardless of smoking status. The poorer antiplatelet response in clopidogrel-treated nonsmokers may provide an explanation for the smokers' paradox. (The Influence of Smoking Status on Prasugrel and Clopidogrel Treated Subjects Taking Aspirin and Having Stable Coronary Artery Disease; NCT01260584).

Recovery of platelet function after discontinuation of prasugrel or clopidogrel maintenance dosing in aspirin-treated patients with stable coronary disease: the recovery trial.

OBJECTIVES: The goal of this study was to assess the offset of the antiplatelet effects of prasugrel and clopidogrel. BACKGROUND: Guidelines recommend discontinuing clopidogrel at least 5 days and prasugrel at least 7 days before surgery. The pharmacodynamic basis for these recommendations is limited. METHODS: Aspirin-treated patients with coronary artery disease were randomly assigned to either prasugrel 10 mg or clopidogrel 75 mg daily for 7 days. Platelet reactivity was measured before study drug administration and for up to 12 days during washout. The primary endpoint was the cumulative proportion of patients returning to baseline reactivity after study drug discontinuation. RESULTS: A total of 56 patients were randomized; 54 were eligible for analysis. Platelet reactivity was lower 24 h after the last dose of prasugrel compared with clopidogrel. After prasugrel, ≥75% of patients returned to baseline reactivity by washout day 7 compared with day 5 after clopidogrel. Recovery time was dependent on the level of platelet reactivity before study drug exposure and the initial degree of platelet inhibition after study drug discontinuation but not on treatment assignment. CONCLUSIONS: Recovery time after thienopyridine discontinuation depends on the magnitude of on-treatment platelet inhibition, resulting, on average, in a more delayed recovery with prasugrel compared with clopidogrel. The offset of prasugrel was consistent with current guidelines regarding the recommended waiting period for surgery after discontinuation. (Prasugrel/Clopidogrel Maintenance Dose Washout Study; NCT01014624).

The onset of inhibition of platelet aggregation with prasugrel compared with clopidogrel loading doses using gatekeeping analysis of integrated clinical pharmacology data.

The purpose of this analysis was to determine the time by which a prasugrel 60-mg loading dose (LD) achieved significantly greater inhibition of platelet aggregation (IPA) than the peak IPA after a clopidogrel 300-mg LD or 600-mg LD. Data were pooled from nine studies representing 587 individuals: 274 healthy subjects and 313 patients with stable coronary artery disease. The primary pharmacodynamic measure was IPA using 20 [mu]M adenosine-5'-diphosphate as the agonist. Gatekeeping analysis compared the peak IPA at 4, 6, and 24 hours after a clopidogrel 300-mg or 600-mg LD with IPA at various prior time points backwards after a prasugrel LD until a statistically nonsignificant difference was reached. Prasugrel 60-mg LD produced greater IPA by 30 minutes than the peak IPA after a clopidogrel 300-mg LD (P < 0.0001). Significantly greater IPA was achieved at 1 hour after prasugrel 60-mg LD compared with the peak IPA after 600-mg clopidogrel LD (P < 0.0001), regardless of sex, body weight, or age and as early as 30 minutes in the diabetic subgroup. A prasugrel 60-mg LD produces significantly faster onset and greater IPA compared with a clopidogrel 300-mg LD or 600-mg LD.

The association of cigarette smoking with enhanced platelet inhibition by clopidogrel.

OBJECTIVES: The purpose of this study was to examine the effect of cigarette smoking on the platelet response to clopidogrel. BACKGROUND: Response variability to clopidogrel therapy has been demonstrated. Clopidogrel is metabolically activated by several hepatic cytochrome P450 (CYP) isoenzymes, including CYP1A2. Cigarette smoking induces CYP1A2 and may, therefore, enhance the conversion of clopidogrel to its active metabolite. METHODS: Among 259 consecutive patients undergoing elective coronary stenting; 120 were on chronic clopidogrel therapy and were not loaded; and 139 were clopidogrel naïve and were loaded with 600 mg. There were 104 current smokers (CS) and 155 nonsmokers (NS). The adenosine diphosphate (ADP)-stimulated platelet aggregation (PA) was assessed by conventional aggregometry. The ADP-stimulated total and active glycoprotein (GP) IIb/IIIa expression were assessed with flow cytometry. Low PA was defined as the lowest quartile of 5 micromol/l ADP-induced post-treatment PA. RESULTS: Current smokers on chronic clopidogrel therapy displayed significantly lower PA and ADP-stimulated active GP IIb/IIIa expression compared with NS (p < or = 0.0008 for both). Similarly, CS treated with 600 mg of clopidogrel displayed greater platelet inhibition and lower active GP IIb/IIIa expression compared with NS (p < or = 0.05). In a multivariate Cox regression analysis, current smoking was an independent predictor of low PA (p = 0.0001). CONCLUSION: Clopidogrel therapy in CS is associated with increased platelet inhibition and lower aggregation as compared with NS. The mechanism of the smoking effect deserves further study and may be an important cause of response variability to clopidogrel therapy.