Effect of timing of clopidogrel administration on 30-day clinical outcomes: 300-mg loading dose immediately after coronary stenting versus pretreatment 6 to 24 hours before stenting in a large unselected patient cohort

P2Y12 Inhibitor Loading Time Before Elective PCI and the Prevention of Myocardial Necrosis

BACKGROUND

There are dated and conflicting data about the optimal timing of initiation of P2Y12 inhibitors in elective percutaneous coronary intervention (PCI). Peri-PCI myocardial necrosis is associated with poor outcomes. We aimed to assess the impact of the P2Y12 inhibitor loading time on periprocedural myocardial necrosis in the population of the randomized Assessment of Loading With the P2Y12 Inhibitor Ticagrelor or Clopidogrel to Halt Ischemic Events in Patients Undergoing Elective Coronary Stenting (ALPHEUS) trial, which compared ticagrelor with clopidogrel in high-risk patients who received elective PCI.

METHODS

The ALPHEUS trial divided 1809 patients into quartiles of loading time. The ALPHEUS primary outcome was used (type 4 [a or b] myocardial infarction or major myocardial injury) as well as the main secondary outcome (type 4 [a or b] myocardial infarction or any type of myocardial injury).

RESULTS

Patients in the first quartile group (Q1) presented higher rates of the primary outcome (P = 0.01). When compared with Q1, incidences of the primary outcome decreased in patients with longer loading times (adjusted odds ratio [adjOR], 0.70 [0.52.-0.95]; P = 0.02 for Q2; adjOR 0.65 [0.48-0.88]; P < 0.01 for Q3; adjOR 0.66 [0.49-0.89]; P < 0.01 for Q4). Concordant results were found for the main secondary outcome. There was no interaction with the study drug allocated by randomization (clopidogrel or ticagrelor). Bleeding complications (any bleeding ranging between 4.9% and 7.3% and only 1 major bleeding at 48 hours) and clinical ischemic events were rare and did not differ among groups.

CONCLUSIONS

In elective PCI, administration of the oral P2Y12 inhibitor at the time of PCI could be associated with more frequent periprocedural myocardial necrosis than an earlier administration. The long-term clinical consequences remain unknown.

Effect of pretreatment with a P2Y12 inhibitor in patients with non-ST-elevation acute coronary syndrome: a systematic review and network meta-analysis

Background

This study aimed to systematically evaluate the effects of different types and doses of pretreatment with P2Y12 inhibitors in patients with non-ST-elevation acute coronary syndrome (NSTE-ACS) undergoing percutaneous coronary intervention (PCI).

Methods

Electronic databases were searched for studies comparing pretreatment with different types and doses of P2Y12 inhibitors or comparison between P2Y12 inhibitor pretreatment and nonpretreatment. Electronic databases included the Cochrane Library, PubMed, EMBASE, and Web of Science. Literature was obtained from the establishment of each database until June 2022. The patients included in the study had pretreatment with P2Y12 inhibitors with long-term oral or loading doses, or conventional aspirin treatment (non-pretreatment). The primary endpoint was major adverse cardiac and cerebrovascular events (MACCEs) during follow-up within 30 days after PCI, which included determining the composite endpoints of cardiac death, myocardial infarction, ischemia-driven revascularization, and stroke. The safety endpoint was a major bleeding event.

Results

A total of 119,014 patients from 21 studies were enrolled, including 13 RCTs and eight observational studies. A total of six types of interventions were included-nonpretreatment (placebo), clopidogrel pretreatment, ticagrelor pretreatment, prasugrel pretreatment, double loading pretreatment (double loading dose of clopidogrel, ticagrelor, prasugrel) and P2Y12 inhibitors pretreatment (the included studies did not distinguish the types of P2Y12 inhibitors, including clopidogrel, ticagrelor, and prasugrel). The network meta-analysis results showed that compared to patients without pretreatment, patients receiving clopidogrel pretreatment (RR = 0.78, 95% CI:0.66, 0.91, P < 0.05) and double-loading pretreatment (RR = 0.62, 95% CI:0.41, 0.95, P < 0.05) had a lower incidence of MACCEs. There was no statistically significant difference in the incidence of major bleeding events among the six pretreatments (P > 0.05).

Conclusions

In patients with NSTE-ACS, pretreatment with P2Y12 inhibitors before percutaneous intervention reduced the incidence of recurrent ischemic events without increasing the risk of major bleeding after PCI compared with nonpretreatment. Clopidogrel or double loading dose P2Y12 inhibitors can be considered for the selection of pretreatment drugs.

Effectiveness of Pretreatment With Dual Oral Antiplatelet Therapy

Several observational studies, randomized controlled trials, and meta-analyses suggested that pretreatment with clopidogrel in addition to aspirin could reduce the rate of ischemic events, especially in the setting of acute coronary syndromes. Newer P2Y12 inhibitors like prasugrel and ticagrelor, which provide faster and stronger platelet inhibition compared with clopidogrel, would enhance the benefits of pretreatment. However, 2 recent randomized trials, A Comparison of Prasugrel at PCI or Time of Diagnosis of Non-ST Elevation Myocardial Infarction and the Administration of Ticagrelor in the Cath Lab or in the Ambulance for New ST Elevation Myocardial Infarction to Open the Coronary Artery studies, aimed at assessing the effects of the timing of administration of novel P2Y12 inhibitors in acute coronary syndromes, failed to meet their primary end points. In this report, we review clinical data on pretreatment with dual oral antiplatelet therapy and comment on some criticisms raised from recent trials.

Reappraisal of thienopyridine pretreatment in patients with non-ST elevation acute coronary syndrome: a systematic review and meta-analysis

OBJECTIVE

To investigate the effect of pretreatment with P2Y12 receptor inhibitors compared with no pretreatment on efficacy and safety of treatment of non-ST elevation acute coronary syndrome (ACS).

DATA SOURCES

Two reviewers independently searched Medline, Embase, Cochrane Controlled Trials, and BioMed Central databases for randomized placebo controlled trials and observational studies from August 2001 to March 2014.

STUDY ELIGIBILITY

Studies must have reported both all-cause mortality (primary efficacy endpoint) and major bleeding (safety endpoint) outcomes.

DATA EXTRACTION

Data on sample size, characteristics, drug dose and delay of administration, and outcomes were independently extracted and analyzed.

DATA SYNTHESIS

A random-effect model was applied. The analysis was performed (i) in all patients independently of the management strategy and (ii) only in patients undergoing percutaneous coronary intervention.

RESULTS

Of the 393 titles identified, seven (four randomized controlled trials, one observational analysis from a randomized controlled trial, and three observational studies) met the inclusion criteria. No study was identified for ticagrelor or cangrelor, and analyses were thus limited to thienopyridines. A total of 32,383 non-ST elevation ACS patients were included, 18,711 coming from randomized controlled trials. Of these, 55% underwent percutaneous coronary intervention (PCI). Pretreatment was not associated with a significant lower risk of mortality in all patients (odds ratio 0.90 (95% confidence interval 0.75 to 1.07), P=0.24), in particular when considering only the randomized controlled trials (odds ratio 0.90 (0.71 to 1.14), P=0.39). Similar results were observed in the cohort of patients undergoing PCI. A significant 30-45% excess of major bleeding was consistently observed in all patients (odds ratio 1.32 (1.16 to 1.49), P<0.0001) and in those undergoing PCI, as well as in the subset analyses of randomized controlled trials of these two cohorts of patients. There was a reduction in major adverse cardiovascular events in the analysis of all patients (odds ratio 0.84 (0.72 to 0.98), P=0.02), driven by the old clopidogrel studies (CURE and CREDO), but the difference was not significant for the cohort of patients undergoing PCI. Stent thrombosis, stroke, and urgent revascularization did not differ between groups (pretreatment v no pretreatment). The results were consistent for both thienopyridines and confirmed in sensitivity analyses.

LIMITATIONS

Analysis was not performed on individual patient's data.

CONCLUSION

In patients presenting with non-ST elevation ACS, pretreatment with thienopyridines is associated with no significant reduction of mortality but with a significant excess of major bleeding no matter the strategy adopted, invasive or not. Our results do not support a strategy of routine pretreatment in patients with non-ST elevation ACS.

Cangrelor: an emerging therapeutic option for patients with coronary artery disease

OBJECTIVES

To perform a systematic up-to-date review and critical discussion of potential clinical applications of cangrelor based on its pharmacologic properties and the main findings from randomized clinical studies.

METHODS

A database search (PubMed, CENTRAL and Google Scholar) by two independent investigators, including proceedings from scientific sessions of ACC, AHA, ESC, TCT and EuroPCR, from January 1998 through December 2013.

RESULTS

Cangrelor is a potent, intravenous, direct-acting P2Y12 antagonist with rapid onset and quickly reversible action. In contrast to ticagrelor, cangrelor's interaction with thienopiridines requires termination of cangrelor infusion before switching to clopidogrel or prasugrel. According to randomized trials, a cangrelor-clopidogrel combination is relatively safe and more effective than the standard clopidogrel regimen in both urgent and elective percutaneous coronary intervention (PCI) settings, with the advantage of this drug combination fully evident when the universal definition of myocardial infarction is applied. In contrast to available antiplatelet drugs with delayed onset and offset of action, its favorable properties make cangrelor a desirable agent for ad hoc elective PCI, high risk acute coronary syndromes treated with immediate coronary stenting and for bridging those surgery patients who require periprocedural P2Y12 inhibition. Current evidence on cangrelor therapy is limited by the lack of adequately powered studies assessing cangrelor co-administration either with prasugrel or ticagrelor, suboptimal design of some of the trials favoring cangrelor, potentially attenuated benefits with modern stent design, and finally, by the lack of survival advantage.

CONCLUSIONS

With its pharmacokinetic and pharmacodynamic advantages, allowing consistent and strong P2Y12 inhibition, and with its rapid onset and swift reversal of action devoid of need for an antidote, cangrelor might improve clinical outcomes in clopidogrel-treated patients by reducing ischemic events, while maintaining a favorable safety profile. However, further studies, addressing the safety and efficacy of cangrelor on top of novel oral P2Y12 inhibitors, are warranted.

Early clopidogrel versus prasugrel use among contemporary STEMI and NSTEMI patients in the US: insights from the National Cardiovascular Data Registry

Background

P2Y12 antagonist therapy improves outcomes in acute myocardial infarction (MI) patients. Novel agents in this class are now available in the US. We studied the introduction of prasugrel into contemporary MI practice to understand the appropriateness of its use and assess for changes in antiplatelet management practices.

Methods and Results

Using ACTION Registry‐GWTG (Get‐with‐the‐Guidelines), we evaluated patterns of P2Y12 antagonist use within 24 hours of admission in 100 228 ST elevation myocardial infarction (STEMI) and 158 492 Non‐ST elevation myocardial infarction (NSTEMI) patients at 548 hospitals between October 2009 and September 2012. Rates of early P2Y12 antagonist use were approximately 90% among STEMI and 57% among NSTEMI patients. From 2009 to 2012, prasugrel use increased significantly from 3% to 18% (5% to 30% in STEMI; 2% to 10% in NSTEMI; P for trend <0.001 for all). During the same period, we observed a decrease in use of early but not discharge P2Y12 antagonist among NSTEMI patients. Although contraindicated, 3.0% of patients with prior stroke received prasugrel. Prasugrel was used in 1.9% of patients ≥75 years and 4.5% of patients with weight <60 kg. In both STEMI and NSTEMI, prasugrel was most frequently used in patients at the lowest predicted risk for bleeding and mortality. Despite lack of supporting evidence, prasugrel was initiated before cardiac catheterization in 18% of NSTEMI patients.

Conclusions

With prasugrel as an antiplatelet treatment option, contemporary practice shows low uptake of prasugrel and delays in P2Y12 antagonist initiation among NSTEMI patients. We also note concerning evidence of inappropriate use of prasugrel, and inadequate targeting of this more potent therapy to maximize the benefit/risk ratio.

Contemporary antiplatelet therapy in patients undergoing percutaneous coronary intervention

The proper use of antiplatelet agents in the cardiac catheterization laboratory is important for ensuring optimal results in patients undergoing percutaneous revascularization. Understanding the mechanisms by which these drugs exerts their effects is important for both interventional and non-interventional cardiologists. The effects of these agents on platelet function can be assessed and monitored using a variety of commercially available laboratory assays but so far these tests have not been adopted in routine clinical practice. Currently, aspirin, thienopyridines and glycoprotein IIb/IIIa inhibitors are the primary types of antiplatelet drugs being utilized. The use of these drugs and of several newer antiplatelet drugs in the treatment of patients undergoing percutaneous revascularization in the cardiac catheterization laboratory will be discussed, especially in the light of the recently published guidelines.

Antiplatelet effect of thienopyridine (clopidogrel or prasugrel) pretreatment in patients undergoing primary percutaneous intervention for ST elevation myocardial infarction

Although previous retrospective studies have suggested the clinical benefits of clopidogrel pretreatment in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI), the antiplatelet effect of thienopyridines during a narrow door-to-balloon time frame has not been evaluated. Seventy-nine consecutive patients with STEMI were treated with either 600 mg of clopidogrel (n = 49) or 60 mg of prasugrel (n = 30) loading on admission. All patients underwent PPCI with a door-to-balloon time of 48 ± 20 minutes. Adenosine diphosphate (ADP)-induced platelet aggregation (PA) was determined by light transmission aggregometry before thienopyridine loading, at PPCI, and after 72 hours. Baseline ADP-induced PA was comparable in clopidogrel- and prasugrel-treated patients (79 ± 10% vs 76 ± 9%, p = 0.2). Although ADP-induced PA was reduced significantly in both clopidogrel- and prasugrel-treated patients (p <0.01 for both), it was significantly lesser in prasugrel-treated patients (63 ± 18% vs 74 ± 12%, p = 0.002). Yet, <50% of the prasugrel-treated patients achieved adequate platelet inhibition (ADP-induced PA <70%) at PPCI. Prasugrel-treated patients, compared with clopidogrel-treated patients, were more likely to have Thrombolysis In Myocardial Infarction myocardial perfusion grade of ≥2 (79% vs 49%, p = 0.01), lower Thrombolysis In Myocardial Infarction frame count (10.2 ± 5.7 vs 13.6 ± 7.2, p = 0.03), and a numerically greater incidence of early ST-segment resolution >50% (26 of 30 [87%] vs 35 of 49 [71%], p = 0.1), suggesting better myocardial reperfusion. In conclusion, overall, prasugrel compared with clopidogrel pretreatment resulted in greater platelet inhibition at PPCI, but even with prasugrel, only <50% of the patients achieved early adequate platelet response.

Short-term bleeding events observed with clopidogrel loading in acute ischemic stroke patients

INTRODUCTION

The Fast Assessment of Stroke and Transient Ischemic Attack to Prevent Early Recurrence trial raised concern that loading doses of clopidogrel may increase hemorrhagic complications. We investigated if similar rates of hemorrhage occur in patients with acute ischemic stroke (AIS) of varying severity.

METHODS

Patients meeting inclusion criteria were divided into 2 groups: the LOAD group and non-LOAD group. The LOAD group was defined as patients who were administered a loading dose of 300 mg or more of clopidogrel with or without aspirin within 24 hours of admission. The non-LOAD group was devised using propensity score (PS): 55 patients who received a loading dose of clopidogrel of 300 mg or more were matched on PS to 55 patients who did not receive loading doses. These patients were taken from a pool of 341 consecutive ischemic patients ineligible for intravenous or intra-arterial fibrinolysis, 162 of whom received a clopidogrel loading dose and the remainder of whom did not. The frequency of hemorrhage was compared between the 2 groups using Student t test and chi-square. Logistic regression was used to assess the relationship between loading dose and serious bleeding events (symptomatic intracerebral hemorrhage [sICH] or transfusion for systemic bleeding).

RESULTS

AIS patients (N = 596) were screened during the 31-month period of this retrospective study. Of this sample, 170 patients were excluded: 149 patients were excluded because they were treated with intravenous tissue plasminogen activator (IV t-PA) alone, 11 were excluded because they were treated with IV t-PA combined with intra-arterial therapy (IAT), and 10 were excluded for treatment with IAT alone. An additional 85 patients were excluded because they were not admitted to the stroke service or because they had an in-hospital stroke. Baseline characteristics of the groups were well matched. There were no significant differences in the rates of sICH, transfusion, hemorrhagic transformation, or systemic bleeding. Clopidogrel loading was not associated with increased odds of serious bleeding events in the crude model (odds ratio [OR] .92, 95% confidence interval [CI] .27-3.13) or after adjusting for covariates and confounders of interest (OR 1.06, 95% CI .28-4.04).

DISCUSSION

Contrary to our original hypothesis, patients with AIS receiving clopidogrel loading doses within 24 hours of symptom onset did not appear to experience a higher rate of new serious bleeding events during acute hospitalization when compared with patients who did not receive loading doses. The Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke trial is expected to provide insight into the safety of clopidogrel loading as an acute intervention after cerebral ischemia.

Acute coronary syndromes: is there a place for a real pre-hospital treatment for patients "en route" to the coronary intensive care unit?

Acute initial management of patients with acute coronary syndrome (ACS) is based on a precise clinical and electrocardiographic diagnosis. Initial risk stratification in the pre-hospital phase is the key step. The last step, adequate patient routing, is decided based on emergency level and reperfusion strategies, considered right from the pre-hospital phase. The management of a patient with an ACS requires close collaboration between emergency physicians and cardiologists, according to simplified protocols for easier access to catheterisation. The next challenges for the pre-hospital management of ACS are based on: - precise knowledge of new antiplatelet and anticoagulant drugs by the emergency physicians, in order to adjust their prescriptions to the patient profile; - developing co-operation between hospitals, according to regional specificities (geographic considerations and distribution of PCI centres) in order to reduce access time to catheterisation rooms; - organising the healthcare network, where the SAMU has an essential role in coordinating the different medical actors; - regular analysis of the evolution of our professional practices, considering, e.g., the guidelines of the "HAS" (French official healthcare guidelines institute);- integrating pre-hospital medicine in health prevention programmes; - improving our understanding of the population's presentations of coronary artery disease, in order to encourage the patients and their families to call the EMS as soon as possible. The challenge of the emergency physician is to adapt the strategies to the patient's needs.

Optimizing antiplatelet therapy in acute coronary syndrome and percutaneous coronary intervention

Dual antiplatelet therapy with aspirin and clopidogrel is the standard of care for patients with acute coronary syndrome (ACS) and those undergoing percutaneous coronary intervention (PCI). It is well established that inhibition of platelet aggregation reduces the risk of recurrent thrombotic events and stent thrombosis. However, some patients show a reduced antiplatelet response to standard clopidogrel loading (300 mg) and maintenance (75 mg day(-1)) doses, which has been associated with poorer patient outcomes. Pharmacodynamic and pharmacokinetic studies show that higher-than-standard clopidogrel dosing strategies facilitate more rapid platelet inhibition of a greater intensity as a result of greater plasma concentrations of the clopidogrel active metabolite. Recently completed studies suggest that in patients with ACS undergoing PCI, higher-than-standard clopidogrel dosing regimens provide greater inhibition of platelet function and improved clinical outcomes with a small but significant increase in major bleeding. Newer, more potent antiplatelet agents such as prasugrel and ticagrelor are other alternative strategies that result in more rapid, greater inhibition of platelet function and better outcomes than standard-dose clopidogrel. Whether platelet reactivity-guided therapy or genotyping for cytochrome P450 polymorphisms is useful in managing patients needs to be further defined. Most importantly, early and effective antiplatelet therapy results in the best short- and long-term outcomes for patients with ACS or those undergoing PCI.

A comparison of prasugrel at the time of percutaneous coronary intervention or as pretreatment at the time of diagnosis in patients with non-ST-segment elevation myocardial infarction: design and rationale for the ACCOAST study

BACKGROUND

The precise risk/benefit of thienopyridine pretreatment and the optimal dosage and timing of a thienopyridine loading dose (LD) for patients presenting with non-ST-segment elevation (NSTE) acute coronary syndromes are still being debated. Prasugrel, a novel thienopyridine, is an appropriate drug to address this issue as it provides predictably high and rapid inhibition of platelet aggregation.

STUDY DESIGN

ACCOAST is a phase 3, multicenter, parallel-group, double-blind, and event-driven study designed to compare 2 prasugrel LD schedules in patients with NSTE myocardial infarction who are scheduled for coronary angiography/percutaneous coronary intervention (PCI). Approximately 4,100 patients will be randomly assigned to an initial LD of 30 mg of prasugrel after the diagnosis followed by coronary angiography with an additional dose of 30 mg of prasugrel given at the time of PCI (pretreatment) or an LD of 60 mg of prasugrel given to patients undergoing PCI at the time of the procedure (non-pretreatment). All patients undergoing PCI will receive 5 or 10 mg of prasugrel daily. The primary objective is to test the hypothesis that prasugrel pretreatment is superior to prasugrel non-pretreatment as measured by a reduction in the composite end point of cardiovascular death, myocardial infarction, stroke, urgent revascularization, or glycoprotein IIb/IIIa inhibitor bailout through 7 days from randomization. Key safety end points include TIMI (Thrombolysis In Myocardial Infarction) major and minor bleeding risks.

CONCLUSIONS

The ACCOAST study will provide important evidence with regard to the benefits and risks of prasugrel pretreatment compared with administration of prasugrel at the time of PCI in patients with NSTE myocardial infarction.

Antithrombotic therapy in patients with coronary artery disease and with type 2 diabetes mellitus

Diabetes mellitus (DM) is a life-threatening disease. Patients with DM have a 2- to 4-fold higher risk of developing cardiovascular disease compared to their non-diabetic counterparts. Several drugs are available for the treatment of stable coronary artery disease (CAD) and acute coronary syndrome (ACS). Among oral antiplatelet agents (acetylsalicylic acid, ticlopidine, clopidogrel, and prasugrel), prasugrel has shown the highest efficacy in patients with DM and ACS. The use of glycoprotein IIb-IIIa receptor inhibitors in diabetic subjects with ACS undergoing percutaneous coronary intervention (PCI) reduces adverse clinical events in a greater extent than in non-diabetics. Several direct and indirect antithrombins are recommended for the treatment of ACS such as unfractionated heparin (UFH), enoxaparin, fondaparinux, and bivalirudin. Enoxaparin and bivalirudin have been shown to be superior to UFH among patients with ST-elevation MI (STEMI) and non-ST elevation MI (NSTEMI) also in diabetic subgroup analyses.

Antiplatelet therapy in percutaneous coronary intervention: a critical review of the 2007 AHA/ACC/SCAI guidelines and beyond

Antiplatelet therapy is a mainstay in the treatment of patients who have undergone percutaneous coronary intervention (PCI). Although the 2007 PCI treatment guidelines were published by the American College of Cardiology, the American Heart Association, and the Society for Cardiovascular Angiography and Interventions, new clinical evidence has emerged, expanding our understanding of antiplatelet use and potentially affecting the treatment guidelines. For example, clinical trial results prompted a Science Advisory to recommend that dual therapy with aspirin and clopidogrel be used for longer periods-up to 1 year in patients who receive bare metal stents and at least 1 year in patients receiving drug-eluting stents. New trial results have also emerged regarding the use of glycoprotein IIb/IIIa antagonists such as abciximab, eptifibatide, and tirofiban. This article reviews the current recommendations for antiplatelet therapy in PCI patients, recent trial results, newly developed agents, ongoing clinical trials, and the future direction of antiplatelet therapy in patients who undergo PCI.

Contemporary issues on clopidogrel therapy

In this paper, data from available studies regarding some contemporary issues on clopidogrel therapy are analyzed. In particular, the following clinical questions have been considered and addressed: (a) Is early clopidogrel treatment needed in patients with acute coronary syndromes treated medically or undergoing percutaneous coronary intervention (PCI)? (b) What is the optimal clopidogrel loading dose in patients undergoing PCI? (c) Is pre-treatment with clopidogrel before PCI needed, or can clopidogrel loading be given in the catheter laboratory before intervention, but after coronary anatomy is known? (d) What is the optimal clopidogrel strategy in patients on chronic clopidogrel therapy undergoing PCI? (e) Does the degree of clopidogrel response influence clinical outcome in patients undergoing PCI?

Temporal trends and patterns of early clopidogrel use across the spectrum of acute coronary syndromes

BACKGROUND

Randomized trials have established efficacy of clopidogrel in various types of acute coronary syndromes (ACS). The objective of this study was to examine the temporal trends and patterns of early clopidogrel use (within the first 24 hours of hospitalization) across the spectrum of patients with ACS in Canada.

METHODS

Using the multinational, prospective GRACE (Global Registry of Acute Coronary Events) and GRACE(2), we identified 11,177 patients who were admitted for ACS from January 2003 to December 2007 in Canada. Demographic information, clinical features, and treatment were recorded. We examined the early use of clopidogrel over time and in relation to the type of ACS, clinical features on presentation, and the mode of reperfusion therapy.

RESULTS

Of the 11,177 patients with ACS, 3,091 (27.7%) had ST-elevation myocardial infarction (STEMI), 5,194 (46.5%) had non-STEMI, and 2,892 (25.9%) had unstable angina; the rates of early clopidogrel administration were 63.0%, 66.6%, and 57.2%, respectively (P < .001). Overall, there was a significant increase in clopidogrel use over the period studied (P for trend < .001). In patients with non-ST-elevation ACS (non-STEMI and unstable angina), clopidogrel use was higher among those with positive cardiac biomarkers compared to those without (67.1% vs 59.8%, P < .001) but similar in the groups with and without ST deviation. There was an inverse relationship between GRACE risk score and rates of early clopidogrel administration. In patients with STEMI receiving fibrinolytic therapy, only 55.7% of patients <65 years old received clopidogrel compared with 47.0% and 42.6% of patients 65 to 74 and >75 years old, respectively (P for trend < .001).

CONCLUSIONS

Although early use of clopidogrel therapy has increased over time across the spectrum of ACS, a significant proportion of eligible patients still do not receive this evidence-based therapy. There is a need to optimize the use of proven antiplatelet therapies to improve clinical outcome.

Impact of pretreatment with clopidogrel on initial patency and outcome in patients treated with primary percutaneous coronary intervention for ST-segment elevation myocardial infarction: a systematic review

BACKGROUND

The main goal of the initial treatment of ST-segment elevation myocardial infarction is prompt reperfusion of the infarct-related artery. The value of pretreatment with clopidogrel before primary percutaneous coronary intervention is currently unclear.

METHODS AND RESULTS

Studies were retrieved through MEDLINE and Cochrane Controlled Trials Register searches over the past 20 years. Two authors independently performed the study selection and data extraction. Randomized controlled studies were included when the research subjects were unselected patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention. Pilot trials, studies that enrolled patients undergoing rescue percutaneous coronary intervention, and studies with angiographic assessment not performed by a core laboratory or 2 blinded investigators were excluded. Thirty-eight treatment groups, including 8429 patients, were included. Initial patency was higher in treatment groups in which patients received pretreatment with clopidogrel (34.3%; 95% confidence interval, 32.9 to 35.8) compared with those in which patients did not receive clopidogrel before initial coronary angiography (25.8%; 95% confidence interval, 24.5 to 27.1). In multivariate-weighted logistic regression analysis, pretreatment with clopidogrel was an independent predictor of early reperfusion (odds ratio, 1.51; 95% confidence interval, 1.31 to 1.74; P<0.0001) and improved clinical outcome.

CONCLUSIONS

Initial patency and clinical outcome were improved in treatment groups that received pretreatment with clopidogrel. These results in patients undergoing primary percutaneous coronary intervention are in line with the experience of pretreatment with clopidogrel in elective patients, non-ST-elevation coronary syndromes, and thrombolytic studies.

Effects of a waiting period after clopidogrel treatment before performing coronary artery bypass grafting

STUDY OBJECTIVE

To assess the effects of a waiting period after clopidogrel treatment before coronary artery bypass grafting (CABG). Design. Single-center, prospective, observational study.

SETTING

Cardiothoracic surgery intensive care unit at a university-affiliated medical center.

PATIENTS

One hundred consecutive patients who received clopidogrel and were scheduled to undergo primary CABG. In 64 of these patients, CABG was delayed at least 5 days after clopidogrel treatment (group A). The other 36 patients received clopidogrel treatment within 5 days of undergoing CABG (group B).

MEASUREMENTS AND MAIN RESULTS

Data were collected on patient demographics, time of last clopidogrel dose, preoperative anticoagulant and/or antiplatelet agents administered, surgical characteristics, intraoperative transfusions, blood products transfused, and chest tube output for 24 hours after surgery. No significant differences in baseline characteristics or intraoperative variables (number of bypasses, aortic cross-clamp time, and cardiopulmonary bypass time) were noted between the two groups. Mean +/- SD number of packed red blood cell units/patient was 1.1 +/- 1.4 in group A versus 2.1 +/- 2.5 in group B (p=0.009). Mean +/- SD number of platelet units/patient transfused was 0.5 +/- 0.9 in group A versus 1.9 +/- 1.6 in group B (p<0.001). When comparing a subset of 21 patients who received clopidogrel within 72 hours of surgery with the 64 whose CABG was delayed at least 5 days after clopidogrel treatment, the transfusion rates were significantly higher (95% vs 52%, p<0.05). Specifically, the mean +/- SD number of transfused units/patient of red blood cells (3.1 +/- 2.8 vs 1.1 +/- 1.4, p<0.005) and platelets (2.6 +/- 1.5 vs 0.5 +/- 0.9, p<0.007) was greater in patients who received clopidogrel within 72 hours of surgery.

CONCLUSION

A strategy to delay CABG after clopidogrel treatment led to reduced blood product administration. The optimal waiting period after clopidogrel treatment is not known but appears to be at least 5 days before CABG.

Clopidogrel use with stenting

Previous clinical trials have established that clopidogrel is beneficial when used with coronary artery stenting. However, questions remain as to when the clopidogrel treatment should be started and how long treatment should be continued for. In a Clopidogrel Registry, it was shown that when subjects received a loading dose of clopidogrel 300 mg, 6-24 h before the intervention and clopidogrel maintenance for 1 month, the primary end point at 30 days (acute myocardial infarction, all cause death and revascularisation) was lower than in subjects who were just given clopidogrel maintenance. An observational study has shown that there are no additional benefits from continuing to use clopidogrel after 6 months from bare-metal stenting. In contrast, long-term treatment with clopidogrel is beneficial in subjects given drug-eluting stents, when long-term stent thrombosis can be a rare complication. Thus, in subjects given drug-eluting stents, there was an incidence of death and non-fatal myocardial infarction (6-24 months after stenting) of 8.4% without clopidogrel and 2.1% with clopidogrel. These results suggest that clopidogrel pretreatment should be used with stenting, and that with drug-eluting stents, clopidogrel treatment should be continued for at least 24 months.

Clopidogrel

Clopidogrel (Plavix), Iscover) selectively and irreversibly inhibits adenosine diphosphate (ADP)-induced platelet aggregation. Long-term administration of clopidogrel was associated with a modest but statistically significant advantage over aspirin in reducing adverse cardiovascular outcomes in patients with established cardiovascular disease in the CAPRIE trial. In other large well designed multicentre trials, such as CURE, COMMIT and CLARITY-TIMI 28, the addition of clopidogrel to aspirin therapy improved outcomes in patients with acute coronary syndromes. However, some issues regarding the use of clopidogrel remain unresolved, such as the optimal loading dose in patients undergoing percutaneous coronary interventions (PCI) and the optimal treatment duration following drug-eluting intracoronary stent placement. Results of several large randomised trials, therefore, have established clopidogrel as an effective and well tolerated antiplatelet agent for the secondary prevention of ischaemic events in patients with various cardiovascular conditions, including those with ischaemic stroke or acute coronary syndromes. In addition, treatment guidelines from the US and Europe acknowledge the importance of clopidogrel in contemporary cardiovascular medicine.