Effect of smoking on comparative efficacy of antiplatelet agents: systematic review, meta-analysis, and indirect comparison

Smoking and cardiovascular outcomes after percutaneous coronary intervention: a Korean study

BACKGROUND AND AIMS

The authors investigated the impact of smoking and its cessation after percutaneous coronary intervention (PCI) on cardiovascular outcomes.

METHODS

Using a nationwide database from the Korean National Health Insurance System, 74 471 patients undergoing PCI between 2009 and 2016 were classified as non-, ex-, or current smokers, depending on smoking status at the first health check-up within 1 year after PCI. The primary outcome was major adverse cardiovascular and cerebrovascular event (MACCE), a composite of all-cause death, myocardial infarction, coronary revascularization, and stroke.

RESULTS

During 4.0 years of follow-up, current smokers had a 19.8% higher rate of MACCE than non-smokers [adjusted hazard ratio (aHR) 1.198; 95% confidence interval (CI) 1.137-1.263], and ex-smokers tended to have a comparable rate with that of non-smokers (aHR 1.036; 95% CI .992-1.081). For 31 887 patients with both pre- and post-PCI health check-up data, the effects of smoking cessation were analysed. Among quitters who stopped smoking after PCI, quitters with cumulative smoking exposure of <20 pack-years (PYs) tended to have a comparable rate of MACCE with that of persistent non-smokers. However, the rate in quitters with cumulative exposure of ≥20 PYs was comparable with that of persistent smokers [aHR (95% CI) for <10 PY, 1.182 (.971-1.438); 10-20 PYs 1.114 (.963-1.290); 20-30 PYs 1.206 (1.054-1.380); ≥ 30 PYs 1.227 (1.113-1.352); persistent smokers 1.223 (1.126-1.328), compared with persistent non-smokers, respectively, P for interaction <.001].

CONCLUSIONS

Smoking is associated with a higher risk of adverse outcomes in patients undergoing PCI. Quitters after PCI with <20 PYs were associated with a risk comparable with that of non-smokers.

Association between post-stroke smoking and stroke recurrence in first-ever ischemic stroke survivors: based on a 10-year prospective cohort

BACKGROUND

Whether smoking is a risk factor for ischemic stroke (IS) recurrence in IS survivors is still uncovered, and evidences are sparse. Meanwhile, an add-on effect of clopidogrel was observed in myocardial infarction patients who smoked, but whether the paradox exists in IS patients is still unsolved. The objectives of this study are to explore the association between smoking behavior after index stroke and IS recurrence and to explore whether the paradox exists.

METHODS

A prospective cohort of first-ever IS patients was conducted between 2010 and 2019. The prognosis and smoking features of enrolled patients were obtained via telephone follow-up every 3 months. Fine-gray model with interaction terms was applied to measure the relationships between stroke recurrence and smoking behaviors after index stroke and to explore the add-on effect of clopidogrel in smoking patients.

RESULTS

There were 171 (24.26%) recurrences and 129 (18.30%) deaths during follow-up in 705 enrolled IS patients. One hundred forty-six (20.71%) patients smoked after index stroke. The hazard ratios (HRs) and 95% confidence intervals (CIs) of interaction terms between antiplatelet drug and follow-up smoking (smoking status and daily smoking amount) were 1.092 (95% CI: 0.524, 2.276) and 0.985 (95% CI: 0.941, 1.031), respectively. A significantly higher risk of recurrence was observed in patients with a higher daily smoking amount during follow-up (per cigarette), with HR being 1.027 (95% CI: 1.003, 1.052).

CONCLUSIONS

Smoking could elevate the risk of IS recurrence, and IS survivor should be advised to quit or smoke less. Add-on effect of clopidogrel may not exist in smoking strokers taking clopidogrel.

Risk factors associated with contrast-associated acute kidney injury in ST-segment elevation myocardial infarction patients: a systematic review and meta-analysis

OBJECTIVE

The objective of this systematic review and meta-analysis was to evaluate the risk factors for contrast-associated acute kidney injury (CA-AKI) in ST-elevation myocardial infarction patients treated with primary percutaneous coronary intervention.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

We searched the databases of PubMed, Embase and Ovid, up to February 2022, for observational studies that investigated the association between risk factors and CA-AKI.

RESULTS

A total of 21 studies were included in the meta-analysis. Of the total 22 015 participants, 2728 developed CA-AKI. Pooled incidence was 11.91% (95% CI 9.69%, 14.14%). Patients with CA-AKI were more likely to be older, female, also had comorbidities (hypertension, diabetes, previous heart failure). Smoking (OR: 0.60; 95% CI 0.52, 0.69) and family history of CAD (coronary artery disease) (OR: 0.76; 95% CI 0.60, 0.95) were associated with lower risk of CA-AKI. Left anterior descending (LAD) artery occlusion (OR: 1.39; 95% CI 1.21, 1.59), left main disease (OR: 4.62; 95% CI 2.24, 9.53) and multivessel coronary disease (OR: 1.33; 95% CI 1.11, 1.60) were risk factors for CA-AKI. Contrast volume (weighted mean difference: 20.40; 95% CI 11.02, 29.79) was associated with increased risk in patients receiving iso-osmolar or low-osmolar non-ionic contrast.

CONCLUSIONS

In addition to the known risk factors, LAD artery infarction, left main disease and multivessel disease are risk factors for CA-AKI. The unexpected favourable association between smoking, as well as family history of CAD, and CA-AKI requires further investigation.

PROSPERO REGISTRATION NUMBER

CRD42021289868.

Ticagrelor Aspirin vs Clopidogrel Aspirin in CYP2C19 Loss-of-Function Carriers With Minor Stroke or TIA Stratified by Risk Profile

BACKGROUND AND OBJECTIVE

Genotype data of the Clopidogrel with Aspirin in Acute Minor Stroke or Transient Ischemic Attack (CHANCE) trial showed that efficacy of clopidogrel aspirin depended on CYP2C19 genotype and risk profile. A stratification of patients who carried CYP2C19 loss-of-function (LOF) alleles according to the risk of recurrent stroke may be important for selecting optimal antiplatelet therapy. We aimed to compare the efficacy and safety of ticagrelor aspirin with clopidogrel aspirin in CYP2C19 LOF carriers with minor stroke or transient ischemic attack (TIA) stratified by risk profile.

METHODS

Data were obtained from Ticagrelor or Clopidogrel with Aspirin in High-Risk Patients with Acute Nondisabling Cerebrovascular Events II (CHANCE-2) trial. Low-risk and high-risk profiles were defined by Essen Stroke Risk Score (ESRS) (<3 [low risk] and ≥3 [high risk], respectively).

RESULTS

A total of 6,412 CYP2C19 LOF carriers were enrolled; ticagrelor aspirin was associated with a reduced risk of primary outcome (new stroke within 90-day follow-up) in patients at low risk (hazard ratio [HR], 0.65; 95% CI, 0.48-0.82), but not in those at high risk (HR, 0.97; 95% CI, 0.73-1.29), compared with clopidogrel aspirin (p = 0.02 for interaction). Secondary outcomes generally went in the same direction as the primary outcome. The primary safety outcome of severe or moderate bleeding did not differ based on risk profile (p = 0.24 for interaction), although the incidence of total bleeding was greater with ticagrelor aspirin than with clopidogrel aspirin among patients at low risk (p < 0.01 for interaction). Analysis in the per-protocol population yielded similar results.

DISCUSSION

This post hoc analysis of CHANCE-2 trial showed that CYP2C19 LOF carriers with minor stroke or TIA at low risk of recurrent stroke received a greater benefit from ticagrelor aspirin than from clopidogrel aspirin.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that CYP2C19 LOF carriers with minor stroke or TIA at low risk, but not at high risk, of recurrent stroke (by the ESRS) received a greater benefit from ticagrelor aspirin than from clopidogrel aspirin.

TRIAL REGISTRATION INFORMATION

URL: www.

CLINICALTRIALS

gov. Unique identifier: NCT04078737.

Potential effects of icosapent ethyl on cardiovascular outcomes in cigarette smokers: REDUCE-IT smoking

AIMS

Cigarette smoking is among the most well-established risk factors for adverse cardiovascular outcomes. We sought to determine whether icosapent ethyl (IPE), a highly purified form of eicosapentaenoic acid with antiatherothrombotic properties, may reduce the excessive risk of cardiovascular disease (CVD) attributable to smoking.

METHODS AND RESULTS

Reduction of Cardiovascular Events with Icosapent Ethyl Trial (REDUCE-IT) was a multinational, double-blind trial that randomized 8179 statin-treated patients with elevated triglycerides and CV risk to IPE or placebo, with a median follow-up period of 4.9 years. Icosapent ethyl reduced the primary composite endpoint [CV death, non-fatal myocardial infarction (MI), non-fatal stroke, coronary revascularization, or hospitalization for unstable angina] by 25% (P < 0.0001). In the current analyses, the effect of IPE was evaluated in REDUCE-IT using post hoc analyses based on smoking history. Groups were classified as current smokers (n = 1241), former smokers (n = 3672), and never smokers (n = 3264). Compared with placebo, IPE use in combined current and former smokers (n = 4913) was associated with significant reductions in time to the primary composite endpoint {hazard ratio: 0.77 [95% confidence interval (CI): 0.68-0.87]; P < 0.0001} and in total events [rate ratio: 0.71 (95% CI: 0.61-0.82); P < 0.0001]. These benefits remained significant when subdivided into current and former smokers (P = 0.04, P = 0.005), with reductions in the key secondary composite endpoint (P < 0.0001) and in the individual components of CV death or non-fatal MI (P = 0.04, P = 0.01) and fatal or non-fatal MI (P = 0.009, P = 0.01), respectively. Benefits were consistent and significant in non-smokers as well. Overall, there were similar estimated rates of first occurrences of primary CVD endpoints in current smokers (23.8%) and former smokers (23.0%) assigned to IPE compared with never smokers on placebo (25.7%).

CONCLUSION

In REDUCE-IT, IPE treatment was associated with a reduced risk of CV events in current and former smokers to levels observed in never smokers. While smoking cessation should always be recommended, these data raise the possibility that IPE treatment may attenuate CV hazards attributable to smoking.

No Paradoxical Effect of Smoking Status on Recurrent Cardiovascular Events in Patients Following Percutaneous Coronary Intervention: Thai PCI Registry

Background

"Smoker's paradox" is a controversial phenomenon that describes an unexpectedly favorable short-term outcome of smokers post-percutaneous coronary intervention (PCI). This study aimed to evaluate the effect of smoking status on recurrent major adverse cardiovascular events (MACEs) in patients who recently underwent PCI and to determine whether it was paradoxical.

Methods

This study utilized data from the nationwide Thai PCI registry, enrolling patients during 2018-2019. Our study factor was smoking status, classified as current smokers, ex-smokers, and nonsmokers. The outcome of interest was the time to occurrence of a composite of MACEs (i.e., all-cause death, myocardial infarction (MI), stroke, and unplanned revascularization) evaluated at about 1-year post-PCI. A propensity score (PS) model using inverse probability weighting with regression adjustment was used to estimate the effect of smoking on the occurrence of MACE.

Results

Current smokers, ex-smokers, and non-smokers accounted for 23, 32, and 45% of the 22,741 subjects, respectively. Smokers were younger, more frequently male, and had fewer traditional atherosclerotic risk factors. Current smokers presented more frequently with ST-elevation MIs (STEMIs) and cardiogenic shock (54 and 14.6%, respectively) than non-smokers. MACE rates were 1.9, 1.2, and 1.6 per 100 patients per month in the current smokers, ex-smokers, and non-smokers, respectively. After applying a PS, patients with a history of current smoking and ex-smoking developed the onset of recurrent MACEs significantly sooner than non-smokers, with a median time of 4.4 vs. 4.9 vs. 13.5 months (p < 0.001), respectively.

Conclusions

"Smoker's paradox" was not observed in our patient population. Current smokers and ex-smokers were prone to develop an earlier onset of a post-PCI MACEs than nonsmokers and need a smoke cessation program for further prevention.

Bleeding Risk of Dual Antiplatelet Therapy after Minor Stroke or TIA

OBJECTIVE

To identify the risk of bleeding events and potential risk factors within 90 days in patients carried CYP2C19 loss-of-function alleles and received dual antiplatelet therapy after minor stroke or transient ischemic attack.

METHODS

A total of 6,412 patients were enrolled from the Clopidogrel with aspirin in High-risk patients with Acute Non-disabling Cerebrovascular Events II (CHANCE-2) trial. The main outcome was any bleeding within 90 days defined by the criteria from Global Utilisation of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO).

RESULTS

A total of 250 (3.9%) bleeding events were reported, which occurred mainly within the 21 days of dual antiplatelet therapy (200 cases, 3.1%). Minor bleeding of the skin bruises, epistaxis, and gum bleeding was most frequent. Multivariate analysis showed that treatment with ticagrelor-aspirin compared with clopidogrel-aspirin was associated with increased bleeding (hazard ratio [HR], 2.21; 95% confidence interval [CI], 1.68-2.89; P<0.001). Current smoking was associated with a lower risk of bleeding (HR, 0.70; 95% CI, 0.52-0.95; P=0.02). Additionally, ticagrelor-aspirin compared with clopidogrel-aspirin was associated with higher risk of bleeding in patients aged <65 years (HR, 2.87; 95% CI, 1.95-4.22) and those without diabetes mellitus (HR, 2.65; 95% CI, 1.88-3.73) (P for interaction=0.04 and 0.03, respectively).

INTERPRETATION

Bleeding events mostly occurred within the 21-day dual antiplatelet therapy stage and were generally mild. The risk of bleeding was greater in non-smoking patients, and was associated with treatment with ticagrelor-aspirin compared with clopidogrel-aspirin particularly in aged <65 years and non-diabetic patients. This article is protected by copyright. All rights reserved.

ST-segment elevation versus non-ST-segment elevation myocardial infarction in current smokers after newer-generation drug-eluting stent implantation

We compared the 2-year major clinical outcomes between ST-segment elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI) in patients who are current smokers who underwent successful percutaneous coronary intervention (PCI) with newer-generation drug-eluting stents (DESs). The availability of data in this regard is limited.A total of 8357 AMI patients were included and divided into 2 groups: the STEMI group (n = 5124) and NSTEMI group (n = 3233). The primary endpoint was the occurrence of major adverse cardiac events (MACE), defined as all-cause death, recurrent myocardial infarction (re-MI), or coronary repeat revascularization. The secondary endpoints were the cumulative incidences of the individual components of MACE and stent thrombosis (definite or probable).After propensity score-matched (PSM) analysis, 2 PSM groups (2250 pairs, C-statistics = 0.795) were generated. In the PSM patients, both for 1 month and at 2 years, the cumulative incidence of MACE (P = .183 and P = .655, respectively), all-cause death, cardiac death, re-MI, all-cause death or MI, any repeat revascularization, and stent thrombosis (P = .998 and P = .341, respectively) was not significantly different between the STEMI and NSTEMI groups. In addition, these results were confirmed using multivariate analysis.In the era of contemporary newer-generation DESs, both during 1 month and at 2 years after index PCI, the major clinical outcomes were not significantly different between the STEMI and NSTEMI groups confined to the patients who are current smokers. However, further research is needed to confirm these results.

Efficacy and safety of ticagrelor versus prasugrel in smokers and nonsmokers with acute coronary syndromes

BACKGROUND

The efficacy and safety of ticagrelor versus prasugrel according to smoking status in patients with acute coronary syndromes (ACS) are not known. We assessed the efficacy and safety of ticagrelor versus prasugrel according to smoking status in patients with ACS undergoing invasive management.

METHODS

This pre-specified analysis of the ISAR-REACT 5 trial included 1349 smokers and 2652 nonsmokers randomized to receive ticagrelor or prasugrel. The primary endpoint was the incidence of death, myocardial infarction, or stroke; the secondary endpoint was the incidence of Bleeding Academic Research Consortium (BARC) type 3 to 5 bleeding (both endpoints assessed at 12 months).

RESULTS

There was no significant treatment arm-by-smoking status interaction regarding the efficacy outcome. The primary endpoint occurred in 47 patients (7.0%) in the ticagrelor group and 41 patients (6.2%) in the prasugrel group in smokers (hazard ratio [HR] = 1.15; 95% confidence interval [CI] 0.76-1.75; P = 0.510) and in 133 patients (10.2%) in the ticagrelor group and 94 patients (7.2%) in the prasugrel group in nonsmokers (HR = 1.44 [1.10-1.87]; P = 0.007; P for interaction = 0.378). The secondary endpoint occurred in 27 patients (4.6%) in the ticagrelor group and 33 patients (5.6%) in the prasugrel group in smokers (HR = 0.81 [0.49-1.35]; P = 0.412) and in 66 patients (6.0%) in the ticagrelor group and 46 patients (4.4%) in the prasugrel group in nonsmokers (HR = 1.38 [0.94-2.01]; P = 0.097).

CONCLUSIONS

In patients with ACS undergoing an invasive management strategy, the smoking status did not significantly interact with the relative treatment effect of ticagrelor vs. prasugrel.

CLINICAL TRIAL REGISTRATION

NCT01944800.

Association between smoking status and outcomes in myocardial infarction patients undergoing percutaneous coronary intervention

Smoking is one of the leading risk factors for cardiovascular diseases, including ischemic heart disease and hypertension. However, in acute myocardial infarction (AMI) patients, smoking has been associated with better clinical outcomes, a phenomenon termed the “smoker’s paradox.” Given the known detrimental effects of smoking on the cardiovascular system, it has been proposed that the beneficial effect of smoking on outcomes is due to age differences between smokers and non-smokers and is therefore a smoker’s pseudoparadox. The aim of this study was to evaluate the association between smoking status and clinical outcomes in ST-segment elevation (STEMI) and non-STEMI (NSTEMI) patients treated by percutaneous coronary intervention (PCI), using a national multi-ethnic Asian registry. In unadjusted analyses, current smokers had better clinical outcomes following STEMI and NSTEMI. However, after adjusting for age, the protective effect of smoking was lost, confirming a smoker’s pseudoparadox. Interestingly, although current smokers had increased risk for recurrent MI within 1 year after PCI in both STEMI and NSTEMI patients, there was no increase in mortality. In summary, we confirm the existence of a smoker’s pseudoparadox in a multi-ethnic Asian cohort of STEMI and NSTEMI patients and report increased risk of recurrent MI, but not mortality, in smokers.

Association of CYP2C19 Loss-of-Function Alleles with Major Adverse Cardiovascular Events of Clopidogrel in Stable Coronary Artery Disease Patients Undergoing Percutaneous Coronary Intervention: Meta-analysis

PURPOSE

It was aimed to determine the aggregated risk of MACE (major adverse cardiovascular events) in stable CAD patients carrying CYP2C19 LoF alleles taking clopidogrel.

METHODS

Literature was searched in different databases for relevant studies. Aggregated risk was estimated using a fixed/random effect model where p-value<0.05 was considered statistically significant.

RESULTS

In total, 21 studies with 16,194 stable CAD patients were assessed. It was found that patients treated with clopidogrel carrying either one or two CYP2C19 LoF alleles who underwent PCI were associated with significantly increased risk of MACE compared to non-carriers (OR: 1.71, 95% CI: 1.51-1.94, p<0.00001) that was driven from cardiovascular death (OR: 1.43, 95% CI: 1.02-1.99, p=0.04), myocardial infarction (OR: 1.75, 95% CI: 1.42-2.16, p<0.00001), stroke (OR: 2.30, 95% CI: 1.52-3.47, p<0.0001), and stent thrombosis (OR: 4.08, 95% CI: 2.52-6.61, p<0.00001). It was also found that carriers of two CYP2C19 LoF alleles were associated with a significantly marked risk of MACE than non-carriers (OR: 2.22, 95% CI: 1.60-3.09, p<0.00001). Furthermore, the increased risk of MACE remained markedly significant in Asian patients (OR: 2.03, 95% CI: 1.72-2.40, p<0.00001) and was less significant in western patients (OR: 1.35, 95% CI: 1.11-1.63, p=0.002). Bleeding events were not significantly different in carriers of CYP2C19 LoF alleles compared to non-carriers (OR: 1.11, 95% CI: 0.85-1.45, p=0.43).

CONCLUSION

Stable CAD patients treated with clopidogrel and carried CYP2C19 LoF alleles undergoing PCI were associated with significantly increased risk of MACE compared to non-carriers, even markedly significant for Asian patients.

Effect of Smoking on Outcomes of Primary PCI in Patients With STEMI

BACKGROUND

Smoking is a well-established risk factor for ST-segment elevation myocardial infarction (STEMI); however, once STEMI occurs, smoking has been associated with favorable short-term outcomes, an observation termed the "smoker's paradox." It has been postulated that smoking might exert protective effects that could reduce infarct size, a strong independent predictor of worse outcomes after STEMI.

OBJECTIVES

The purpose of this study was to determine the relationship among smoking, infarct size, microvascular obstruction (MVO), and adverse outcomes after STEMI.

METHODS

Individual patient-data were pooled from 10 randomized trials of patients with STEMI undergoing primary percutaneous coronary intervention. Infarct size was assessed at median 4 days by either cardiac magnetic resonance imaging or technetium-99m sestamibi single-photon emission computed tomography. Multivariable analysis was used to assess the relationship between smoking, infarct size, and the 1-year rates of death or heart failure (HF) hospitalization and reinfarction.

RESULTS

Among 2,564 patients with STEMI, 1,093 (42.6%) were recent smokers. Smokers were 10 years younger and had fewer comorbidities. Infarct size was similar in smokers and nonsmokers (adjusted difference: 0.0%; 95% confidence interval [CI]: -3.3% to 3.3%; p = 0.99). Nor was the extent of MVO different between smokers and nonsmokers. Smokers had lower crude 1-year rates of all-cause death (1.0% vs. 2.9%; p < 0.001) and death or HF hospitalization (3.3% vs. 5.1%; p = 0.009) with similar rates of reinfarction. After adjustment for age and other risk factors, smokers had a similar 1-year risk of death (adjusted hazard ratio [adjHR]: 0.92; 95% CI: 0.46 to 1.84) and higher risks of death or HF hospitalization (adjHR: 1.49; 95% CI: 1.09 to 2.02) as well as reinfarction (adjHR: 1.97; 95% CI: 1.17 to 3.33).

CONCLUSIONS

In the present large-scale individual patient-data pooled analysis, recent smoking was unrelated to infarct size or MVO, but was associated with a worse prognosis after primary PCI in STEMI. The smoker's paradox may be explained by the younger age and fewer cardiovascular risk factors in smokers compared with nonsmokers.

Implementing a pharmacogenetic-driven algorithm to guide dual antiplatelet therapy (DAPT) in Caribbean Hispanics: protocol for a non-randomised clinical trial

INTRODUCTION

Minority populations in the USA are disproportionately affected by cardiovascular conditions. Reduced responsiveness to clopidogrel among carriers of CYP2C19 variants has been reported in patients with either coronary artery disease (CAD) or acute coronary syndrome (ACS) after the percutaneous coronary intervention (PCI). Previous studies have evaluated CYP2C19 genotyping-guided antiplatelet therapy in selected populations; however, this has yet to be tested among Hispanics. Given the paucity of clinical research on CYP2C19 and antiplatelet clinical outcomes in Hispanics, our study will test the safety and efficacy of a genetic-driven treatment algorithm to guide dual antiplatelet therapy (DAPT) in Caribbean Hispanics.

METHODS AND ANALYSIS

This is a multicentre, prospective, non-randomised clinical trial that proposes an assessment of pharmacogenomic-guided DAPT in post-PCI Caribbean Hispanic patients with ACS or CAD. We will recruit 250 patients to be compared with a matched non-concurrent cohort of 250 clopidogrel-treated patients (standard-of-care). Major adverse cardiovascular events (MACEs) such as all-cause death, myocardial infarction (MI), stroke, coronary revascularisation, stent thrombosis and bleedings over 6 months will be the study endpoints. Among the recruited, high-risk patients will be escalated to ticagrelor and low-risk patients will remain on clopidogrel. The primary objective is to determine whether genetic-guided therapy is superior to standard of care. The secondary objective will determine if clopidogrel treatment in low-risk patients is not associated with a higher rate of MACEs compared with escalated antiplatelet therapy in high-risk patients. Patients will be enrolled up to the group's completion.

ETHICS AND DISSEMINATION

Approval was obtained from the Institutional Review Board of the University of Puerto Rico Medical Sciences Campus (protocol # A4070417). The study will be carried out in compliance with the Declaration of Helsinki and International Conference on Harmonization Good Clinical Practice Guidelines. Findings will be published in a peer-reviewed journal and controlled access to experimental data will be available.

TRIAL REGISTRATION NUMBER

NCT03419325; Pre-results.

Outcomes After Left Main Coronary Artery Revascularization by Percutaneous Coronary Intervention or Coronary Artery Bypass Grafting According to Smoking Status

Cigarette smoking is a well-known risk factor for coronary artery disease (CAD). However, the impact of smoking on outcomes after coronary revascularization, especially in patients with left main CAD (LMCAD) is less well understood. The EXCEL trial randomized 1,905 patients with LMCAD and visually assessed low or intermediate anatomical complexity (SYNTAX score ≤32) to PCI with everolimus-eluting stents or CABG. Patients were categorized according to smoking status (current, former, or never), and their outcomes at 5 years were compared by logistic regression with follow-up time included as a log-transformed offset variable. The primary endpoint was a composite of death, myocardial infarction, or stroke. Among 1893 patients with known smoking status at baseline, 416 (22%) were current smokers and 774 (41%) were former smokers. The crude rates of the primary endpoint were 19.5% for never smokers, 20.5% for former smokers (p = 0.61 vs never smokers), and 23.1% for smokers (p = 0.15 vs never smokers). Compared with never smokers, the adjusted risk of the primary endpoint was higher for current smokers (adjOR 1.82, 95% confidence interval [CI] 1.126 to 2.63; p = 0.001), but not for former smokers (adjOR 1.00, 95% CI 0.75 to 1.33, p = 0.10). The relative efficacy of PCI versus CABG for the 5-year primary endpoint was similar irrespective of smoking status (P_interaction = 0.22). In conclusion, current smokers in the EXCEL trial had a higher adjusted 5-year risk of the primary composite endpoint of death, myocardial infarction, or stroke than never smokers, whereas former smokers were not at increased risk. Active smoking was a risk factor after LMCAD revascularization irrespective of revascularization method.

Influences of Smoking Status on Effectiveness of Cytochrome P450 Enzyme System Metabolized Medications in Reducing In-Hospital Death in 14 658 Patients With Acute Myocardial Infarction: Data From CPACS-3 Study

BACKGROUND

The benefit of cytochrome P450 (CYP450) enzyme system metabolized medications, especially clopidogrel, was reported more pronounced in smoking than nonsmoking patients, but limited evidence was available from Asian patients. We analyzed data from a large registry-based study of Chinese patients with acute myocardial infarction (AMI) to understand if the above finding could be reproduced.

METHODS

A total of 14 658 patients with AMI were prospectively recruited from 101 hospitals across China. Generalized estimating equation was applied to assess the association between CYP450 enzyme system metabolized medications (clopidogrel, statins, calcium channel blockers) and in-hospital death in smoking and nonsmoking patients, separately, adjusting for hospital clustering effects and propensity score of using the medication in question.

RESULTS

There were 86%, 93%, and 10% of study patients who received clopidogrel, statins, and calcium channel blockers during the hospitalization. Compared with patients not receiving clopidogrel, patients receiving the drug had a significantly lower risk of in-hospital death (adjusted relative risk [RR] = 0.61, 95% confidence interval [CI]: 0.40-0.91) in current smokers but an insignificant lower risk (adjusted RR = 0.85, 95% CI: 0.71-1.01) in nonsmokers, and the P for interaction was <.01. The corresponding adjusted RR was 0.45 (95% CI: 0.24-0.86) in current smokers and 0.94 (95% CI: 0.68-1.29) in nonsmokers (P for interaction <.01) for statins use and 1.00 (95% CI: 0.53-1.89) in current smokers and 0.66 (95% CI: 0.48-0.90) in nonsmokers (P for interaction = .23) for calcium channel blockers use.

CONCLUSIONS

Our study in a large cohort of Chinese patients with AMI found that the treatment effect in reducing risk of in-hospital death was significantly larger in smokers than in nonsmokers as for clopidogrel and statins but not for calcium channel blockers.

Smoking status and mortality outcomes following percutaneous coronary intervention

Objective

The aim of this study was to assess the impact of smoking on short (30-day) and intermediate (30-day to 6-month) mortality following percutaneous coronary intervention (PCI).

Background

The effect of smoking on mortality post-PCI is lacking in the modern PCI era.

Methods

This was a retrospective analysis of prospectively collected data comparing short- and intermediate-term mortality amongst smokers, ex-smokers and non-smokers.

Results

The study cohort consisted of 12,656 patients: never-smokers (n = 4288), ex-smokers (n = 4806) and current smokers (n = 3562). The mean age (±standard deviation) was 57 (±11) years in current smokers compared with 67 (±11) in ex-smokers and 67 (±12) in never-smokers; p &lt; 0.0001. PCI was performed for acute coronary syndrome (ACS) in 84.1% of current smokers, 57% of ex-smokers and 62.9% in never-smokers; p &lt; 0.0001. In a logistic regression model, the adjusted odds ratios (95% confidence intervals (CIs)) for 30-day mortality were 1.60 (1.10–2.32) in current smokers and 0.98 (0.70–1.38) in ex-smokers compared with never-smokers. In the Cox proportional hazard model, the adjusted hazard ratios (95% CI) for mortality between 30 days and 6 months were 1.03 (0.65–1.65) in current smokers and 1.19 (0.84–1.67) in ex-smokers compared with never-smokers.

Conclusion

This large observational study of non-selected patients demonstrates that ex-smokers and never-smokers are of similar age at first presentation to PCI, and there is no short- or intermediate-term mortality difference between them following PCI. Current smokers undergo PCI at a younger age, more often for ACS, and have higher short-term mortality. These findings underscore the public message on the benefits of smoking cessation and the harmful effects of smoking.

Smoking and outcomes following guided de-escalation of antiplatelet treatment in acute coronary syndrome patients: a substudy from the randomized TROPICAL-ACS trial

Aims

Prior analyses disclosed variations in antiplatelet drug response and clinical outcomes between smokers and non-smokers, thus the safety and efficacy of any dual antiplatelet therapy (DAPT) de-escalation strategy may differ in relation to smoking status. Hence, we assessed the impact of smoking on clinical outcomes and adenosine diphosphate-induced platelet aggregation following guided de-escalation of DAPT in invasively managed acute coronary syndrome (ACS) patients.

Methods and results

The multicentre TROPICAL-ACS trial randomized 2610 biomarker-positive ACS patients 1:1 to standard treatment with prasugrel for 12 months (control group) or a platelet function testing guided de-escalation of DAPT. Current smokers (n = 1182) showed comparable event rates between study groups [6.6% vs. 6.6%; hazard ratio (HR) 1.0, 95% confidence interval (CI) 0.64–1.56, P &gt; 0.99]. In non-smokers (n = 1428), a guided DAPT de-escalation was associated with a lower 1-year incidence of the primary endpoint [cardiovascular death, myocardial infarction, stroke, or bleeding ≥ Grade 2 according to Bleeding Academic Research Consortium (BARC) criteria] compared with control group patients (7.9% vs. 11.0%; HR 0.71, 95% CI 0.50–0.99, P = 0.048). This reduction was mainly driven by a lower rate of BARC ≥ Grade 2 bleedings (5.2% vs. 7.7%; HR 0.68, 95% CI 0.45–1.03, P = 0.066). There was no significant interaction of smoking status with treatment effects of guided DAPT de-escalation (Pint = 0.23). Adenosine diphosphate-induced platelet aggregation values were higher in current smokers [median 28 U, interquartile range (IQR: 20–40)] vs. non-smoker [median 24 U (16–25), P &lt; 0.0001] in the control group and in current smokers [median 42 U, IQR (27–68)] vs. non-smoker [median 37 U, IQR (25–55), P &lt; 0.001] in the monitoring group.

Conclusion

Guided DAPT de-escalation appears to be equally safe and effective in smokers and non-smokers. Regardless of smoking status and especially for those patients deemed unsuitable for 1 year of potent platelet inhibition this DAPT strategy might be used as an alternative antiplatelet treatment regimen.

Effectiveness and Safety of Platelet ADP -P2Y12 Receptor Inhibitors Influenced by Smoking Status: A Systematic Review and Meta-Analysis

Background As reports on the influence of cigarette smoking, an important cardiovascular risk factor, on platelet ADP -P2Y12 receptor inhibitors lack consistency, we aimed to assess the effectiveness and safety of platelet ADP -P2Y12 receptor inhibitors influenced by smoking status. Methods and Results PubMed, Web of Science, EMBASE , Clinical Trials, and the Cochrane Library were searched from inception until June 2018. Among the 5076 citations retrieved, 22 studies, including 163 011 patients with or without percutaneous coronary intervention, were included for meta-analysis. Compared with nonsmokers within the first year of follow-up, the reductions of stroke and major adverse cardiovascular event rate were 18% ( P=0.008) and 26% ( P=0.02), respectively. A 20% reduction in stroke ( P=0.02) and a 34% reduction in major adverse cardiovascular event ( P=0.0001) rates were observed in smoking patients without percutaneous coronary intervention. No significant difference was observed in clinical outcome rates among prasugrel, ticagrelor, and clopidogrel in different smoking status. No significant difference was found in myocardial infarction and bleeding event incidence between current smokers and nonsmokers. Conclusions We concluded that current smokers had a lower incidence of major adverse cardiovascular events and stroke events than did nonsmokers, particularly in the early period (1 year) and among patients without percutaneous coronary intervention. However, because of the lack of original adjusted data, smoker's paradox still needs to consider the impact of age and other covariates. Thus, a differential risk-benefit evaluation should be considered, according to different smoking status, patient conditions, and therapy time points.

Precision medicine in COPD: where are we and where do we need to go?

Chronic obstructive pulmonary disease (COPD) was the fourth leading cause of death worldwide in 2015. Current treatments for patients ease discomfort and help decrease disease progression; however, none improve lung function or change mortality. COPD is heterogeneous in its molecular and clinical presentation, making it difficult to understand disease aetiology and define robust therapeutic strategies. Given the complexity of the disease we propose a precision medicine approach to understanding and better treating COPD. It is possible that multiOMICs can be used as a tool to integrate data from multiple fields. Moreover, analysis of electronic medical records could aid in the treatment of patients and in the predictions of outcomes. The Precision Medicine Initiative created in 2015 has made precision medicine approaches to treat disease a reality; one of these diseases being COPD.

Pharmacogenetic association study on clopidogrel response in Puerto Rican Hispanics with cardiovascular disease: a novel characterization of a Caribbean population

Introduction

High on-treatment platelet reactivity (HTPR) to clopidogrel imparts an increased risk for ischemic events in adults with coronary artery disease. Platelet reactivity varies with ethnicity and is influenced by both clinical and genetic variables; however, no clopidogrel pharmacogenetic studies with Puerto Rican patients have been reported. Therefore, we sought to identify clinical and genetic determinants of on-treatment platelet reactivity in a cohort of Puerto Rican patients with cardiovascular disease.

Methods

We performed a retrospective study of 111 patients on 75 mg/day maintenance dose of clopidogrel. Patients were allocated into 2 groups: Group I, without HTPR; and Group II, with HTPR. Platelet function was measured ex vivo using the VerifyNow® P2Y12 assay and HTPR was defined as P2Y12 reaction units (PRU) ≥230. Genotyping testing was performed using Taqman^® Genotyping Assays.

Results

The mean PRU across the cohort was 203±61 PRU (range 8–324), and 42 (38%) patients had HTPR. Multiple logistic regression showed that 27% of the total variation in PRU was explained by a history of diabetes mellitus, hematocrit, CYP2C19*2, and PON1 p.Q192R. Body mass index (odds ratio [OR]=1.15; 95% CI: 1.03–1.27), diabetes mellitus (OR=3.46; 95% CI: 1.05–11.43), hematocrit (OR=0.75; 95% CI: 0.65–0.87), and CYP2C19*2 (OR=4.44; 95% CI: 1.21–16.20) were the only independent predictors of HTPR.

Conclusion

Moreover, we propose a predictive model to determine PRU values as measured by VerifyNow P2Y12 assay for the Puerto Rican Hispanic population. This model has the potential to identify Hispanic patients at higher risk for adverse events on clopidogrel.

Double-Dose Versus Standard-Dose Clopidogrel According to Smoking Status Among Patients With Acute Coronary Syndromes Undergoing Percutaneous Coronary Intervention

Background

Prior Studies have suggested better outcomes in smokers compared with nonsmokers receiving clopidogrel (“smoker's paradox”). The impact of a more intensive clopidogrel regimen on ischemic and bleeding risks in smokers with acute coronary syndromes requiring percutaneous coronary interventions remains unclear.

Methods and Results

We analyzed 17 263 acute coronary syndrome patients undergoing percutaneous coronary intervention from the CURRENT‐OASIS 7 (Clopidogrel and Aspirin Optimal Dose Usage to Reduce Recurrent Events—Seventh Organization to Assess Strategies in Ischemic Symptoms) trial, which compared double‐dose (600 mg day 1;150 mg days 2–7; then 75 mg daily) versus standard‐dose (300 mg day 1; then 75 mg daily) clopidogrel in acute coronary syndrome patients. The primary outcome was cardiovascular death, myocardial infarction, or stroke at 30 days. Interactions between treatment allocation and smoking status (current smokers versus nonsmokers) were evaluated. Overall, 6394 patients (37.0%) were current smokers. For the comparison of double‐ versus standard‐dose clopidogrel, there were significant interactions in smokers and nonsmokers for the primary outcome (P=0.031) and major bleeding (P=0.002). Double‐ versus standard‐dose clopidogrel reduced the primary outcome among smokers by 34% (hazard ratio [HR] 0.66, 95% confidence interval [CI], 0.50–0.87, P=0.003), whereas in nonsmokers, there was no apparent benefit (HR 0.96, 95% CI, 0.80–1.14, P=0.61). For major bleeding, there was no difference between the groups in smokers (HR 0.77, 95% CI, 0.48–1.24, P=0.28), whereas in nonsmokers, the double‐dose clopidogrel regimen increased bleeding (HR 1.89, 95% CI, 1.37–2.60, P<0.0001). Double‐dose clopidogrel reduced the incidence of definite stent thrombosis in smokers (HR 0.41, 95% CI, 0.24–0.71) and nonsmokers (HR 0.63, 95% CI, 0.42–0.93; P for interaction=0.19).

Conclusions

In smokers, a double‐dose clopidogrel regimen reduced major cardiovascular events and stent thrombosis after percutaneous coronary intervention, with no increase in major bleeding. This suggests that clopidogrel dosing in patients with acute coronary syndromes should be personalized, taking into consideration both ischemic and bleeding risk.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov. Unique identifier: NCT00335452.

Quantifying Ischemic Risk After Percutaneous Coronary Intervention Attributable to High Platelet Reactivity on Clopidogrel (From the Assessment of Dual Antiplatelet Therapy with Drug-Eluting Stents Study)

Patients at high risk of thrombotic events after percutaneous coronary intervention (PCI) may potentially benefit from intensified antiplatelet therapy. However, more potent antiplatelet therapy would be expected to only overcome risk that is mediated by high platelet reactivity (PR). We used mediation analysis to determine the contribution of residual PR to the 2-year risk of major adverse cardiac events (MACE; the composite of cardiac death, myocardial infarction, or stent thrombosis) associated with clinical risk factors after PCI with drug-eluting stents (DES) in 8,374 patients from the prospective, multicenter Assessment of Dual AntiPlatelet Therapy with Drug-Eluting Stents (ADAPT-DES) registry. Residual PR on clopidogrel, as measured by the VerifyNow P2Y12 point-of-care assay, was included as a continuous linear mediator variable in Cox proportional hazards regression. Among 7 factors independently associated with 2-year MACE, residual PR partly mediated the effect of diabetes (13.4% attributable risk), anemia (22.9% attributable risk), and acute coronary syndromes (7.3% attributable risk). A PR-mediated effect inversely affected the MACE risk associated with smoking (10.4% attributable risk). The increased ischemic risk of chronic kidney disease, multivessel disease, and previous myocardial infarction were not mediated by residual PR. In conclusion, high residual PR mediates little or none of the increased 2-year MACE risk associated with baseline risk factors in patients treated with clopidogrel after successful PCI with DES. Intensifying antiplatelet therapy is therefore unlikely to substantially mitigate the excess ischemic risk from these variables.

Discordance Between VASP Phosphorylation and Platelet Aggregation in Defining High On-Clopidogrel Platelet Reactivity After ST-Segment Elevation Myocardial Infarction

To investigate potential clinical characteristics associated with discordance between platelet vasodilator-stimulated phosphoprotein phosphorylation (VASP-P) flow cytometry (FCM) assay and light transmission aggregometry (LTA) in defining high on-clopidogrel platelet reactivity (HPR) after ST-segment elevation myocardial infarction (STEMI). In this study, platelet responsiveness was measured by the above 2 methods simultaneously on day 1 and on day 6 of STEMI onset in 90 consecutive patients who underwent primary percutaneous coronary intervention. The FCM-derived platelet reactivity index and LTA-derived platelet aggregation rate were both significantly reduced after dual antiplatelet therapy on day 6. Multiple variable-adjusted logistic regression analysis revealed that smoking (odds ratio [OR]: 4.507, 95% confidence interval [CI]: 1.123-18.09, P = .034) and onset-to-admission time (per 1 hour increase, OR: 1.196, 95% CI: 1.023-1.398, P = .025) both were independent predictors for the discordance between the 2 methods. Additionally, improved correlation and concordance was observed in nonsmokers compared with smokers. Our data show that smoking and prolonged onset-to-admission time are associated with discordance between platelet VASP-P and LTA in defining HPR after STEMI, which should be considered when planning personalized antiplatelet therapy.

Clinical determinants of clopidogrel responsiveness in a heterogeneous cohort of Puerto Rican Hispanics

BACKGROUND

Clopidogrel is by far the most prescribed platelet adenosine diphosphate (ADP) antagonist in Puerto Rico despite the advent of newer agents (prasugrel and ticagrelor). Given the paucity of data on clopidogrel responsiveness in Hispanics, we sought to determine the association between clinical characteristics and platelet reactivity in Puerto Rican patients on clopidogrel therapy.

STUDY POPULATION

A total of 100 Puerto Rican patients on clopidogrel therapy were enrolled and allocated into two groups: Group I, without high on-treatment platelet reactivity (HTPR); and Group II, with HTPR. Platelet function was measured ex vivo using the VerifyNow® P2Y12 assay.

RESULTS

The cohort was comprised of Hispanic patients with coronary artery disease (57%), peripheral artery disease (32%), carotid artery stenosis (7%), cerebral artery aneurysm (2%), and stroke (2%). Mean platelet reactivity was 200 ± 61 P2Y12 reaction units (PRUs) (range: 8-324), and 35% of patients had HTPR (PRUs ⩾ 230). Multivariable logistic regression analysis determined that diabetes mellitus (DM) [odds ratio (OR) = 3.27; 95% confidence interval (CI): 1.20-8.96], use of proton-pump inhibitors (PPIs) (OR = 3.60; 95% CI: 1.09-11.82), and calcium channel blockers (CCBs) (OR = 3.10; 95% CI: 1.09-8.83) were independent predictors of HTPR ( p < 0.05) after adjusting for other clinical variables.

CONCLUSIONS

In a sample of 100 Puerto Rican Hispanic patients on clopidogrel, 35% had HTPR. Furthermore, DM, PPIs and CCBs predicted HTPR. Clinical outcome data are needed to identify appropriate PRU thresholds for risk prediction in the Puerto Rican population.

UPLC-MS/MS method for the determination of tobacco-specific biomarker NNAL, tamoxifen and its main metabolites in rat plasma

Cigarette smoke is known to interact with tamoxifen-metabolizing enzymes and transporters and potentially affect its treatment outcome. 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanol (NNAL) is an important metabolite of 4-(methylnitro-samino)-1-(3-pyridyl)-1-butanone (NNK) because it is frequently used as a biomarker to assess human smoke exposure. In order to study the potential pharmacokinetic interaction between cigarette smoke and tamoxifen in rats a UPLC-MS/MS method for the simultaneous determination of NNAL and tamoxifen along with its metabolites in rat plasma has been developed and validated. Analytes were extracted with methanol and separated on a HSS T3 column by a gradient elution with the mobile phase consisting of acetonitrile and water. The lower limits of quantitation ranged from 0.05 to 0.62 ng/mL. Precisions showed RSD <15.8% and accuracy in the range 80.6-116.0%. Mean analyte recoveries ranged from 76.9 to 108.4%. The method was successfully applied to study the effects of cigarette smoke condensate (CSC), NNK and benzo(a)pyrene pre-treatment on the pharmacokinetics of tamoxifen and its metabolites in rats. Significant effects of CSC, NNK, benzo(a)pyrene were observed on pharmacokinetics of tamoxifen and its metabolites. We also found that plasma NNAL levels are statistically significant correlated with plasma 4-hydroxy-tamoxifen and endoxifen.

Clopidogrel and ischemic stroke outcomes by smoking status: Smoker's paradox?

BACKGROUND AND PURPOSE

Active smokers with myocardial infarction were shown to have enhanced benefit with clopidogrel compared with aspirin. Whether this "paradox" exists in ischemic stroke patients is unknown. We aimed to investigate whether smoking status has a differential impact on the efficacy of clopidogrel vs. aspirin in patients with non-cardioembolic strokes.

METHODS

This single-center study retrospectively assessed 1792 non-cardioembolic ischemic stroke patients discharged from January 2013 to October 2014, and followed for 12months. Patients were categorized as current-smokers and never-smokers. Primary outcome was a composite of secondary ischemic stroke, myocardial infarction and all-cause death. Secondary outcome was secondary ischemic stroke.

RESULTS

1066 patients were current-smokers and 726 were never-smokers. Compared with never-smokers, current-smokers had significantly higher rates of ischemic stroke (4.3% vs. 1.2%; adjusted OR: 3.60, 95%CI: 1.50-8.64, p=0.004). Regarding the primary outcome, among smokers, rates showed a lower trend in clopidogrel vs. aspirin groups (3.7% vs. 6.4%; adjusted OR 0.57, 95%CI: 0.31-1.07, p=0.08), but no difference among never-smokers (2.1% vs. 1.0%; adjusted OR: 1.67, 95%CI: 0.47-5.89, p=0.42). Similarly, among smokers, trending lower rates for recurrent ischemic stroke were observed in clopidogrel vs. aspirin group (3.1% vs. 5.0%; adjusted OR: 0.60, 95%CI: 0.31-1.18, p=0.14); but no difference between the two groups among never-smokers (1.7% vs. 1.0%; adjusted OR 1.36, 95%CI: 0.36-5.52, p=0.65).

CONCLUSIONS

Smoking is a major risk factor for recurrent stroke in our retrospective non-cardioembolic ischemic stroke cohort. Active-smokers trend toward better cardiovascular outcomes when on clopidogrel. This finding needs to be confirmed in a prospective cohort.

Drugs and Diseases Interacting with Cigarette Smoking in US Prescription Drug Labelling

The US Food and Drug Administration (FDA) draft guidance for industry on drug interaction studies recommends, but does not mandate, that both cigarette smokers and non-smokers can be used to study drug metabolism in clinical trials, and that important results related to smoking should be included in drug labelling to guide medication usage. This study aimed to provide a comprehensive review of drugs or diseases interacting with smoking, as presented in all US drug labelling. The 62,857 drug labels deposited in the FDA Online Label Repository were searched using the keywords 'smoke', 'smoker(s)', 'smoking', 'tobacco' and 'cigarette(s)' on 19 June 2014. The resultant records were refined to include only human prescription drug labelling, for manual examination. For 188 single-active-ingredient drugs and 36 multiple-active-ingredient drugs, the labelling was found to contain smoking-related information. The pharmacokinetics of 29 and 21 single-active-ingredient drugs were affected and unaffected, respectively, by smoking. For the remaining drugs, the provided information related to smoking affecting efficacy, safety or diseases but not pharmacokinetics. Depending on the nature of specific drugs, the perturbation in pharmacokinetic parameters in smokers ranged from 13 to 500%, in comparison with non-smokers. Dosage modifications in smokers are necessary for four drugs and may be necessary for six drugs, but are unnecessary for seven drugs although the pharmacokinetic parameters of four of them are affected by smoking. Cigarette smoking is a risk factor for 16 types of diseases or adverse drug reactions. For one single-active-ingredient contraceptive drug and 10 multiple-active-ingredient contraceptive drugs, a black box warning (the FDA's strongest safety warning) is included in the labelling for increased risks of heart attacks and strokes in female smokers, and "women are strongly advised not to smoke" when using these drugs. This study presents the first comprehensive overview of cigarette smoking interacting with drugs and/or diseases, as presented in US drug labelling.

Vascular risk levels affect the predictive value of platelet reactivity for the occurrence of MACE in patients on clopidogrel. Systematic review and meta-analysis of individual patient data

Prior studies have shown an association between high on-clopidogrel platelet reactivity (PR) and the risk of major adverse cardiovascular events (MACE). However, large intervention trials on PR-tailored treatments have been neutral. The role and usefulness of PR with regard to levels of cardiovascular risk are unclear. We undertook a systematic review and meta-analysis of individual patient data on MACE outcomes (acute coronary syndromes (ACS), ischaemic strokes, and vascular deaths) in relation to PR and its interaction with cardiovascular risk levels. PR was determined using ADP-induced light transmission aggregometry with a primary concentration of 20 µM ADP. Thirteen prospective studies totaled 6,478 clopidogrel-treated patients who experienced 421 MACE (6.5 %) during a median follow-up of 12 months. The strength of the association between the risk of MACE and PR increased significantly (p=0.04) with the number of risk factors present (age> 75 years, ACS at inclusion, diabetes, and hypertension). No association was detected in patients with no risk factor (p=0.48). In patients presenting one risk factor, only high-PR was associated with an increased risk of MACE (HR 3.2, p=0.001). In patients presenting ≥ 2 risk factors, the increase of risk started from medium-PR (medium-PR: HR=2.9, p=0.0004; high-PR: HR=3.7, p=0.0003). PR allowed the reclassification of 44 % of the total population to a different risk level for the outcome of MACE, mostly in intermediate or high risk patients. In conclusion, the magnitude of the association between PR and MACE risk is strongly dependent on the level of cardiovascular risk faced by patients on clopidogrel.

Effect of Active Smoking on Comparative Efficacy of Antithrombotic Therapy in Patients With Atrial Fibrillation: The Loire Valley Atrial Fibrillation Project

BACKGROUND

Active smoking is associated with elevated thrombotic risk. Smoking status has recently been incorporated into the SAMe-TT2R2 (sex female, age < 60 years, medical history [more than two comorbidities], treatment [interacting drugs, eg, amiodarone for rhythm control], tobacco use [doubled], race [doubled]) score that can help predict poor international normalized ratio control in patients with atrial fibrillation (AF) treated with vitamin K antagonists (VKAs). The clinical benefit of antiplatelet therapy (APT) has been seen primarily in smokers. We hypothesized that active smoking may differently influence the risks of stroke and bleeding in patients with AF treated with VKAs or with APT.

METHODS

We examined the clinical course of 7,809 consecutive patients with AF seen between 2000 and 2010. Outcomes in patients who were active smokers were compared with those in other patients.

RESULTS

Among 7,809 patients with AF, 1,034 (13%) were active smokers. APT was prescribed on an individual basis for 2,761 patients (35%) and VKAs for 4,534 (57%). After a follow-up of 929 ± 1,082 days (median = 463 days, interquartile range = 1,564 days), smoking was not independently associated with a higher risk of stroke/thromboembolic event in patients with AF (hazard ratio [HR], 0.95; 95% CI, 0.78-1.22; P = .66). On multivariate analysis, smoking was independently associated with a worse prognosis for the risk of severe bleeding (HR, 1.23; 95% CI, 1.01-1.49; P = .04) and for the risk of major Bleeding Academic Research Consortium bleeding (HR, 1.40; 95% CI, 1.02-1.90; P = .03). Smoking was independently associated with a higher risk of bleeding in patients treated with VKAs (HR, 1.32; 95% CI, 1.04-1.67; P = .02), whereas the risk was nonsignificant in patients treated with APT (HR, 1.28; 95% CI, 0.94-1.74; P = .11).

CONCLUSIONS

In AF, there was a higher risk of severe bleeding in smokers, mainly in those treated with VKAs.

Predictors of high on-clopidogrel platelet reactivity in patients with acute coronary syndrome

High on-clopidogrel platelet reactivity (HPR) is a predictor of ischemic events after percutaneous coronary intervention. We conducted a prospective cohort study to identify variables related to HPR in acute coronary syndrome patients who are at high thrombotic risk. We enrolled 463 patients undergoing urgent coronary angiography. Platelet reactivity was measured 12-36 hours after 600 mg clopidogrel loading with multiple electrode aggregometry (Multiplate® analyzer, Roche, Basel, Switzerland, 6.4 µM ADP). HPR was defined by the consensus cut-off area under the curve >46 U. The rate of HPR was 16.0%. We analyzed simple clinical and laboratory parameters with backward multivariate logistic regression and identified the following predictors of HPR: platelet count (per G/L, OR: 1.0073, 95% CI: 1.0035-1.0112, p = 0.0002), CRP level (per mg/L, OR: 1.0077, 95% CI: 1.0016-1.01372, p = 0.01), and active smoking (OR: 0.51, 95% CI: 0.29-0.89, p = 0.02). We developed and internally validated a risk prediction model demonstrating moderate discriminative capacity (area-under-the-receiver operating characteristic curve = 0.67). In conclusion, we found a relatively low rate of high on-clopidogrel platelet reactivity (16.0%) even in an acute patient cohort. HPR measured by Multiplate was associated with high platelet count and CRP level on admission and was inversely related to active smoking. The model with rapidly available simple parameters might help to identify individuals at risk for HPR in the acute setting.

Antiplatelet strategies for secondary prevention of stroke and TIA

Stroke is a major public health issue, and stroke recurrence accounts for a quarter of all events. Antiplatelet therapy has been extensively studied for secondary stroke prevention and is established as effective in this high-risk population. Several agents have been evaluated in this setting, both in isolation and combination. The most widely used antiplatelet medications are aspirin, clopidogrel, and aspirin plus extended-release dipyridamole. However, new agents and combinations continue to be evaluated. A detailed review of the evidence supporting various antiplatelet regimens for secondary stroke prevention is outlined with special focus on recent developments that may impact clinical management of patients with stroke or TIA.

Does the response to aspirin and clopidogrel vary over 6 months in patients with ischemic heart disease?

BACKGROUND

Dual-antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor, mostly clopidogrel, is the default therapy in both acute coronary syndrome (ACS) and after intracoronary stents. It is well established that responses to antiplatelet therapy (APT), particularly clopidogrel, are subject to considerable interindividual variability.

OBJECTIVES

We investigated whether responses to APT in individuals vary significantly over time.

METHODS

Simultaneous assay with VerifyNow(™) and short thrombelastography (s-TEG) was performed before and at four time points over 6 months after hospital discharge in 40 patients receiving DAPT. Serum thromboxane B2 levels were also measured.

RESULTS

While aspirin response units (ARU) by VerifyNow(™) and serum thromboxane B2 levels remained stable over time, arachidonic acid (AA)-mediated platelet aggregation with s-TEG (i.e. area under the curve at 15 min in AA channel, AUC15AA ) increased at 1 week compared with predischarge (P < 0.008). In addition, platelet reactivity units (PRU) by VerifyNow(™) (P = 0.046) and adenosine diphosphate (ADP)-mediated platelet aggregation with s-TEG (i.e. AUC15ADP ) also increased at 1 week compared with predischarge (P = 0.026). There were no significant changes in either platelet reactivity or rates of high on-treatment platelet reactivity while receiving clopidogrel beyond 1 week.

CONCLUSIONS

This study demonstrates important variability in responses to APT within individuals between predischarge and 1 week but not thereafter. The use of a single early (predischarge) platelet function assay as an indicator of future response may therefore be flawed. The design of future strategies to assess individual responses for tailored therapy needs to take this into account.

Aberrant circulating levels of purinergic signaling markers are associated with several key aspects of peripheral atherosclerosis and thrombosis

RATIONALE

Purinergic signaling plays an important role in inflammation and vascular integrity, but little is known about purinergic mechanisms during the pathogenesis of atherosclerosis in humans.

OBJECTIVE

The objective of this study is to study markers of purinergic signaling in a cohort of patients with peripheral artery disease.

METHODS AND RESULTS

Plasma ATP and ADP levels and serum nucleoside triphosphate diphosphohydrolase-1 (NTPDase1/CD39) and ecto-5'-nucleotidase/CD73 activities were measured in 226 patients with stable peripheral artery disease admitted for nonurgent invasive imaging and treatment. The major findings were that ATP, ADP, and CD73 values were higher in atherosclerotic patients than in controls without clinically evident peripheral artery disease (P<0.0001). Low CD39 activity was associated with disease progression (P=0.01). In multivariable linear regression models, high CD73 activity was associated with chronic hypoxia (P=0.001). Statin use was associated with lower ADP (P=0.041) and tended to associate with higher CD73 (P=0.054), while lower ATP was associated with the use of angiotensin receptor blockers (P=0.015).

CONCLUSIONS

Purinergic signaling plays an important role in peripheral artery disease progression. Elevated levels of circulating ATP and ADP are especially associated with atherosclerotic diseases of younger age and smoking. The antithrombotic and anti-inflammatory effects of statins may partly be explained by their ability to lower ADP. We suggest that the prothrombotic nature of smoking could be a cause of elevated ADP, and this may explain why cardiovascular patients who smoke benefit from platelet P2Y12 receptor antagonists more than their nonsmoking peers.

Comparison of the efficacy of pharmacoinvasive management for ST-segment elevation myocardial infarction in smokers versus non-smokers (from the Trial of Routine Angioplasty and Stenting After Fibrinolysis to Enhance Reperfusion in Acute Myocardial Infarction)

Compared with non-smokers, cigarette smokers with ST-segment elevation myocardial infarctions derive greater benefit from fibrinolytic therapy. However, it is not known whether the optimal treatment strategy after fibrinolysis differs on the basis of smoking status. The Trial of Routine Angioplasty and Stenting After Fibrinolysis to Enhance Reperfusion in Acute Myocardial Infarction (TRANSFER-AMI) randomized patients with ST-segment elevation myocardial infarctions to a routine early invasive (pharmacoinvasive) versus a standard (early transfer only for rescue percutaneous coronary intervention or delayed angiography) strategy after fibrinolysis. The efficacy of these strategies was compared in 1,051 patients on the basis of their smoking status. Treatment heterogeneity was assessed between smokers and non-smokers, and multivariable analysis was performed to evaluate for an interaction between smoking status and treatment strategy after adjusting for baseline Global Registry of Acute Coronary Events (GRACE) risk score. Smokers (n=448) were younger, had fewer cardiovascular risk factors, and had lower GRACE risk scores. They had a lower rate of the primary composite end point of 30-day mortality, reinfarction, recurrent ischemia, heart failure, or cardiogenic shock and fewer deaths or reinfarctions at 6 months and 1 year. Smoking status was not a significant predictor of either primary or secondary end points in multivariable analysis. Pharmacoinvasive management reduced the primary end point compared with standard therapy in smokers (7.7% vs 13.6%, p=0.04) and non-smokers (13.1% vs 19.7%, p=0.03). Smoking status did not modify treatment effect on any measured outcomes (p>0.10 for all). In conclusion, compared with non-smokers, current smokers receiving either standard or early invasive management of ST-segment elevation myocardial infarction after fibrinolysis have more favorable outcomes, which is likely attributable to their better baseline risk profile. The beneficial treatment effect of a pharmacoinvasive strategy is consistent in smokers and non-smokers.

CYP2C19 genotype has a greater effect on adverse cardiovascular outcomes following percutaneous coronary intervention and in Asian populations treated with clopidogrel: a meta-analysis

BACKGROUND

The degree to which cytochrome P450 (CYP) 2C19 genotype influences the effectiveness of clopidogrel remains uncertain because of considerable heterogeneity in results between studies and potential publication bias. Clopidogrel indication and ethnic population have been proposed to influence the effect of CYP2C19 genotype.

METHODS AND RESULTS

A systematic review was undertaken up to 14 November 2013. Meta-analysis of the CYP2C19 genotype effect was stratified by the predominant clopidogrel indication (percutaneous coronary intervention [PCI] versus non-PCI) and ethnic population (white versus Asian) of each primary study. The primary analysis was restricted to studies with ≥500 participants, which comprised 24 studies and a total of 36 076 participants. The association between carriage of ≥1 CYP2C19 loss-of-function (LoF) allele and major cardiovascular outcomes differed significantly (P<0.001) between studies of whites not undergoing PCI (relative risk 0.99 [95% confidence interval, 0.84-1.17]; n=7043), whites undergoing PCI (1.20 [1.10-1.31]; n=19,016), and Asians undergoing PCI (1.91 [1.61-2.27]; n=10,017). Similar differences were identified in secondary analyses of 2 CYP2C19 LoF alleles, stent thrombosis outcomes, and studies with ≥200 participants. Minimal heterogeneity was apparent between studies of Asian populations.

CONCLUSIONS

The reported association between CYP2C19 LoF allele carriage and major cardiovascular outcomes differs based on the ethnic population of the study and, to a lesser extent, the clopidogrel indication. This is potentially of major importance given that over 50% of Asians carry ≥1 CYP2C19 LoF alleles.

Association of P2Y12 gene promoter DNA methylation with the risk of clopidogrel resistance in coronary artery disease patients

Background. Clopidogrel inhibits the ADP receptor P2Y12 to keep down the platelet aggregation. The goal of our study is to investigate the contribution of P2Y12 promoter DNA methylation to the risk of clopidogrel resistance (CR). Methods. The platelet functions were measured by the VerifyNow P2Y12 assay. Applying the bisulfite pyrosequencing technology, DNA methylation levels of two CpG dinucleotides on P2Y12 promoter were tested among 49 CR cases and 57 non-CR controls. We also investigated the association among P2Y12 DNA methylation, various biochemical characteristics, and CR. Result. Lower methylation of two CpGs indicated the poorer clopidogrel response (CpG1, P = 0.009; CpG2, P = 0.022) in alcohol abusing status. Meanwhile CpG1 methylation was inversely correlated with CR in smoking patients (P = 0.026) and in subgroup of Albumin < 35 (P = 0.002). We observed that the level of DNA methylation might be affected by some clinical markers, such as TBIL, LEVF, Albumin, AST. The results also showed that the quantity of stent, fasting blood-glucose, and lower HbAC1 were the predictors of CR. Conclusions. The evidence from our study indicates that P2Y12 methylation may bring new hints to elaborate the pathogenesis of CR.

Impact of smoking on long-term outcomes in patients with atherosclerotic vascular disease treated with aspirin or clopidogrel: insights from the CAPRIE trial (Clopidogrel Versus Aspirin in Patients at Risk of Ischemic Events)

OBJECTIVES

The goal of this study was to investigate the differential efficacy of clopidogrel or aspirin monotherapy according to smoking status in patients with atherosclerotic vascular disease.

BACKGROUND

Smoking enhances clopidogrel-induced platelet inhibition, which may explain the higher relative benefit among smokers observed in trials evaluating dual antiplatelet therapy. Whether smoking has an impact on clinical outcomes in patients requiring a single antiplatelet agent remains unknown.

METHODS

This was a post-hoc analysis of the CAPRIE (Clopidogrel Versus Aspirin in Patients at Risk of Ischemic Events) trial that compared clopidogrel and aspirin monotherapy in patients (N = 19,184) with atherosclerotic vascular disease.

RESULTS

Current smokers (n = 5,688) had an increased risk of ischemic events compared with never smokers (n = 4,135; hazard ratio [HR]: 1.24 [95% confidence interval (CI): 1.08 to 1.42]) and ex-smokers (n = 9,381; HR: 1.32 [95% CI: 1.18 to 1.47]) (p < 0.001). Clopidogrel was associated with a reduction in ischemic events among current smokers (8.3% vs. 10.8%; HR: 0.76 [95% CI: 0.64 to 0.90]), whereas no benefit over aspirin was seen in the combined group of ex-smokers/never-smoked patients (10.4% vs. 10.6%; HR: 0.99 [95% CI: 0.89 to 1.10]; p = 0.01 for interaction). Among current smokers, clopidogrel also reduced myocardial infarction, vascular death, and death from any cause compared with aspirin. No interaction between smoking status and study treatment was observed for bleeding events.

CONCLUSIONS

In a post-hoc analysis of the CAPRIE population, current smokers appeared to have enhanced benefit with clopidogrel therapy for secondary prevention compared with aspirin. These results should be considered hypothesis generating for future prospective studies assessing the impact of specific platelet-inhibiting strategies according to smoking status.