Ticagrelor or Clopidogrel Monotherapy vs Dual Antiplatelet Therapy After Percutaneous Coronary Intervention: A Systematic Review and Patient-Level Meta-Analysis

Importance

Among patients undergoing percutaneous coronary intervention (PCI), it remains unclear whether the treatment efficacy of P2Y12 inhibitor monotherapy after a short course of dual antiplatelet therapy (DAPT) depends on the type of P2Y12 inhibitor.

Objective

To assess the risks and benefits of ticagrelor monotherapy or clopidogrel monotherapy compared with standard DAPT after PCI.

Data Sources

MEDLINE, Embase, TCTMD, and the European Society of Cardiology website were searched from inception to September 10, 2023, without language restriction.

Study Selection

Included studies were randomized clinical trials comparing P2Y12 inhibitor monotherapy with DAPT on adjudicated end points in patients without indication to oral anticoagulation undergoing PCI.

Data Extraction and Synthesis

Patient-level data provided by each trial were synthesized into a pooled dataset and analyzed using a 1-step mixed-effects model. The study is reported following the Preferred Reporting Items for Systematic Review and Meta-Analyses of Individual Participant Data.

Main Outcomes and Measures

The primary objective was to determine noninferiority of ticagrelor or clopidogrel monotherapy vs DAPT on the composite of death, myocardial infarction (MI), or stroke in the per-protocol analysis with a 1.15 margin for the hazard ratio (HR). Key secondary end points were major bleeding and net adverse clinical events (NACE), including the primary end point and major bleeding.

Results

Analyses included 6 randomized trials including 25 960 patients undergoing PCI, of whom 24 394 patients (12 403 patients receiving DAPT; 8292 patients receiving ticagrelor monotherapy; 3654 patients receiving clopidogrel monotherapy; 45 patients receiving prasugrel monotherapy) were retained in the per-protocol analysis. Trials of ticagrelor monotherapy were conducted in Asia, Europe, and North America; trials of clopidogrel monotherapy were all conducted in Asia. Ticagrelor was noninferior to DAPT for the primary end point (HR, 0.89; 95% CI, 0.74-1.06; P for noninferiority = .004), but clopidogrel was not noninferior (HR, 1.37; 95% CI, 1.01-1.87; P for noninferiority > .99), with this finding driven by noncardiovascular death. The risk of major bleeding was lower with both ticagrelor (HR, 0.47; 95% CI, 0.36-0.62; P < .001) and clopidogrel monotherapy (HR, 0.49; 95% CI, 0.30-0.81; P = .006; P for interaction = 0.88). NACE were lower with ticagrelor (HR, 0.74; 95% CI, 0.64-0.86, P < .001) but not with clopidogrel monotherapy (HR, 1.00; 95% CI, 0.78-1.28; P = .99; P for interaction = .04).

Conclusions and Relevance

This systematic review and meta-analysis found that ticagrelor monotherapy was noninferior to DAPT for all-cause death, MI, or stroke and superior for major bleeding and NACE. Clopidogrel monotherapy was similarly associated with reduced bleeding but was not noninferior to DAPT for all-cause death, MI, or stroke, largely because of risk observed in 1 trial that exclusively included East Asian patients and a hazard that was driven by an excess of noncardiovascular death.

P2Y12 Inhibitor Monotherapy or Dual Antiplatelet Therapy After Complex Percutaneous Coronary Interventions

BACKGROUND

It remains unclear whether P2Y₁₂ inhibitor monotherapy preserves ischemic protection while limiting bleeding risk compared with dual antiplatelet therapy (DAPT) after complex percutaneous coronary intervention (PCI).

OBJECTIVES

We sought to assess the effects of P2Y₁₂ inhibitor monotherapy after 1-month to 3-month DAPT vs standard DAPT in relation to PCI complexity.

METHODS

We pooled patient-level data from randomized controlled trials comparing P2Y₁₂ inhibitor monotherapy and standard DAPT on centrally adjudicated outcomes after coronary revascularization. Complex PCI was defined as any of 6 criteria: 3 vessels treated, ≥3 stents implanted, ≥3 lesions treated, bifurcation with 2 stents implanted, total stent length >60 mm, or chronic total occlusion. The primary efficacy endpoint was all-cause mortality, myocardial infarction, and stroke. The key safety endpoint was Bleeding Academic Research Consortium (BARC) 3 or 5 bleeding.

RESULTS

Of 22,941 patients undergoing PCI from 5 trials, 4,685 (20.4%) with complex PCI had higher rates of ischemic events. The primary efficacy endpoint was similar between P2Y₁₂ inhibitor monotherapy and DAPT among patients with complex PCI (HR: 0.87; 95% CI: 0.64-1.19) and noncomplex PCI (HR: 0.91; 95% CI: 0.76-1.09; P_interaction = 0.770). The treatment effect was consistent across all the components of the complex PCI definition. Compared with DAPT, P2Y₁₂ inhibitor monotherapy consistently reduced BARC 3 or 5 bleeding in complex PCI (HR: 0.51; 95% CI: 0.31-0.84) and noncomplex PCI patients (HR: 0.49; 95% CI: 0.37-0.64; P_interaction = 0.920).

CONCLUSIONS

P2Y₁₂ inhibitor monotherapy after 1-month to 3-month DAPT was associated with similar rates of fatal and ischemic events and lower risk of major bleeding compared with standard DAPT, irrespective of PCI complexity. (PROSPERO [P2Y12 Inhibitor Monotherapy Versus Standard Dual Antiplatelet Therapy After Coronary Revascularization: Individual Patient Data Meta-Analysis of Randomized Trials]; CRD42020176853).

Oral Presentation No. 53 Dose-related preprocedural patency of the infarct-related artery after zalunfiban (RUC-4) administration upon arrival at the catheterization laboratory in ST-elevation myocardial infarction: insights from the phase IIa study

Background

The importance of time to reperfusion after ST-elevation myocardial infarction (STEMI) is well established. Pre-hospital use of glycoprotein IIb/IIIa (GPIIb/IIIa) inhibitors improves pre-percutaneous coronary intervention (PCI) perfusion rates, but they require intravenous administration and continuous infusions and so are difficult for ambulance services to administer. Zalunfiban (RUC-4) is a novel, subcutaneously administered, GPIIb/IIIa inhibitor specifically developed to facilitate pre-hospital administration, thereby maximizing the chance for early reperfusion. This sub-analysis investigated the incidence of complete reperfusion (TIMI grade 3 flow) before primary PCI in patients treated with zalunfiban on arrival at the catheterization laboratory as a function of the dose of zalunfiban.

Material and methods

This was a prospective, single-centre, open-label, phase IIa study designed to assess the pharmacodynamics, pharmacokinetics, and tolerability of zalunfiban in patients with STEMI undergoing primary PCI. Zalunfiban was administered immediately upon arrival at the catheterization lab, which was ∼10–15 minutes before the initial angiogram used to assess TIMI grade flow.

Results and conclusion

A total of 27 patients received a weight-adjusted subcutaneous injection of zalunfiban in escalating doses (0.075 mg/kg [n = 8], 0.090 mg/kg [n = 9], or 0.110 mg/kg [n = 10]). Of these, 25 patients were evaluable for angiographic analysis. TIMI flow grade 3 pre-PCI was observed in 1/7, 2/9 and 5/9 patients and showed a dose-related effect (Ptrend = 0.04). The ongoing international, phase III, double-blinded, randomized, placebo-controlled, CELEBRATE trial is designed to assess whether a single, ambulance-based pre-hospital injection of zalunfiban results in improved clinical outcome.

Funding

This study was supported by CeleCor Therapeutics.

Impact of different antiplatelet therapy cessation modes on outcomes in patients treated with ticagrelor with or without aspirin after PCI: the twilight-antiplatelet cessation study

Background

The Ticagrelor With Aspirin or Alone in High-Risk Patients After Coronary Intervention (TWILIGHT) trial showed that a regimen consisting of a 3-month dual antiplatelet therapy (DAPT) followed by ticagrelor monotherapy reduces the rate of bleeding events without increasing ischemic complications compared with standard DAPT [1]. Previous studies, such as Patterns of Non-Adherence to Anti-Platelet Regimens in Stented Patients (PARIS) demonstrated how deviation or cessation of the prescribed antiplatelet regimen might negatively affect clinical outcomes [2].

Purpose

The proposed analysis aims to assess the impact of different antiplatelet therapy cessation patterns on ischemic and bleeding outcomes in patients treated with ticagrelor with or without aspirin after percutaneous coronary intervention (PCI).

Methods

All 7,119 patients randomized at 3 months post-PCI in the TWILIGHT study will be included. The analyses will be conducted separately in the two treatment arms (ticagrelor plus placebo and ticagrelor plus aspirin). According to the PARIS study definitions and as prespecified in the TWILIGHT trial protocol, the occurrence of the three following antiplatelet cessation modes will be assessed: 1) discontinuation (e.g., caused by intolerable side effects or because of a safety concern); 2) interruption (temporary, &lt;14 days, because of surgical or other invasive procedures); 3) disruption (due to non-compliance or bleeding).

The primary endpoint will be the composite of all-cause death, myocardial infarction (MI), or stroke at 12 months after randomization. The key secondary endpoint will be BARC type 2, 3 or 5 bleeding. Other secondary endpoints will include the components of the primary endpoint, cardiovascular death, definite or probable stent thrombosis and BARC types 3 or 5 bleeding. The number of events will be estimated according to the antiplatelet cessation status before the clinical event. Hazard ratios and 95% confidence intervals will be generated using Cox proportional hazards models including antiplatelet therapy cessation as a time-updated variable. If more than one cessation event occurred during follow-up, the antiplatelet therapy cessation category will change only if the more recent mode is worse than the previous: disruption will have priority over interruption, which in turn will have priority over discontinuation. Patients without cessation events will represent the reference group. All adverse events and episodes of antiplatelet cessation were independently adjudicated.

Results

The results of this analysis will be presented for the first time at ESC 2022.

Conclusion

This prespecified analysis of the TWILIGHT study will show for the first time the impact on clinical outcomes of different antiplatelet therapy cessation modes when a regimen of Ticagrelor with our without aspirin is prescribed after PCI.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Astra Zeneca, United Kingdom

Safety and efficacy of biodegradable polymer biolimus-eluting stents in patients with non-ST-elevation acute coronary syndrome: a pooled analysis of GLASSY and TWILIGHT

Background

Biodegradable polymer (BP) drug-eluting stents (DES) have shown similar safety and efficacy compared with second-generation durable polymer (DP)-DES in several randomized trials and meta-analyses. However, study participants were generally maintained on a standard dual antiplatelet therapy (DAPT) for at least 6 months after percutaneous coronary intervention (PCI). Therefore, the differences in thrombogenicity between these two stent technologies may have been unappreciated, especially among patients with acute coronary syndrome (ACS).

Purpose

We aimed to compare the safety and efficacy of BP Biolimus-Eluting Stent (BP-BES) versus 2nd generation DP-DES among ACS patients undergoing PCI and receiving ticagrelor alone or in combination with aspirin.

Methods

We pooled individual patient-level data from two randomized controlled trials, the Ticagrelor With Aspirin or Alone in High-Risk Patients After Coronary Intervention (TWILIGHT, n=9,006) (1) and the GLOBAL LEADERS Adjudication Sub-Study (GLASSY, n=7,585) (2). In order to reduce biases related to trial design differences, only NST-ACS patients not fulfilling any exclusion criterion of both studies were included and 2 separate analysis for short (0 to 3 months after PCI) and long-term (3 to 12 months after PCI) outcomes were performed. Patients were stratified according to the stent used at index PCI (BP-BES vs 2nd generation DP-DES). In both analysis, the primary outcome was major adverse cardiovascular events (MACE, a composite of cardiovascular death, myocardial infarction and definite or probable stent thrombosis); the key secondary outcomes were target-vessel failure (TVF) and BARC 2, 3 or 5 bleeding. Events rate and risk were assessed separately for the two study periods and subsequently 12-months risk estimates were derived by pooling the results of the two analysis.

Results

Out of 7,729 and 6,572 NST-ACS patients included in the two analysis, 2,321 (30%) and 2,211 (33.6%) received a BP-BES, respectively. Among patients treated with BP-BES versus DP-DES, the occurrence of MACE was similar at 3 months after PCI (1.1% vs 1.4%, adjusted HR 0.81, 95% CI 0.51–1.29), while it was significantly lower in the former group between 3 and 12 months (1.7% vs 3.1%, adj. HR 0.46, 95% CI 0.32–0.67) and in the overall period (pooled adjusted HR estimate 0.58, 95% CI 0.43–0.77).

Similarly, significant differences were observed for TVF and BARC 2, 3, or 5 bleeding, whose risk at 12 months was lower among BP-BES than DP-DES patients (pooled adj. HR estimate 0.49, 95% CI 0.38–0.63 and 0.79, 95% CI 0.79, 95% CI 0.65–0.97, respectively).

Conclusion

As compared to 2nd generation DP-DES, BP-BES was associated with a lower risk of MACE, TVF and bleeding among NST-ACS patients undergoing PCI and treated with ticagrelor with or without aspirin. The findings of this analysis are exploratory and need further confirmation.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Biosensors (Singapore)

Abstract 10220: CSL112 (Apolipoprotein A-I (human)) Infusion Rapidly Increases ApoA-I Exchange Rate via Specific Serum Amyloid-Poor HDL Sub-Populations When Administered to Patients Post Myocardial Infarction

Background: Apolipoprotein A-I (apoA-I) exchange rate (AER) into plasma high density lipoprotein (HDL) may represent a cell-free measure of HDL function, and predict recurrent major adverse cardiovascular events post-acute myocardial infarction (AMI).

Purpose: To characterise the effects of CSL112 (apoA-I (human)) on AER and the relationships with specific HDL subpopulations when administered in the 90-day high-risk period post AMI.

Methods: Patients from the AEGIS-I (ApoA-I Event Reducing in Ischemic Syndromes I) study received either placebo, 2g or 6g CSL112 post AMI. The rate of apoA-I exchange into HDL was measured in AEGIS-I plasma samples incubated with fluorescent apoA-I-NBD (7-nitrobenz-2-oxa-1,3-diazole) lipid-sensitive reporter for 30 min at 37°C. HDL particle size distribution was assessed by native gel electrophoresis followed by fluorescent imaging and detection of apoA-I and serum amyloid A (SAA1/SAA2) by western blotting.

Results: CSL112 infusion increased AER peaking 2 h post infusion and returning to baseline by 24 h. AER was correlated with cholesterol efflux capacity, HDL-C, apoA-I and phosphatidylcholine (all p<0.001). CSL112 infusion induced transient changes in HDL particle size distribution. Small remodelled HDL (S-HDL rem ) derived from CSL112 were detected in plasma 2-4 h after infusion. Large remodeled HDL species (L-HDL rem ) accumulated 2-12 h post infusion. The apoA-1-NBD reporter was confined to distinct HDL subpopulations that contained little SAA. In plasma samples characterized by the baseline pattern of HDL particle size distribution (0 h and 24-48 h post infusion), the apoA-I-NBD reporter predominantly exchanged into the HDL3 subpopulation, but not into large HDL2.

Conclusion: Infusion of CSL112 increased AER via exchange into SAA-poor HDL particles. AER may represent a clinically amenable biomarker of HDL functionality. Figure: HDL particle remodelling and AER in a representative subject infused with 6g CSL112 .

CSL112 (human apolipoprotein A-I) infusion rapidly increases apoA-I exchange rate (AER) when administered to patients post myocardial infarction

Background

Cholesterol efflux capacity (CEC) measured using patient serum and cultured macrophages is considered a biomarker of high-density lipoprotein (HDL) functionality. This parameter is inversely related to incident cardiovascular events and declines in the days post-acute myocardial infarction (AMI). The apolipoprotein A-I (apoA-I) exchange rate (AER) may represent an alternative, clinically amenable cell-free measure of CEC, which has also been associated with incident cardiovascular events (1).

Purpose

To characterise the effects of human apoA-I (CSL112) infusion on AER over 48 hours when administered post AMI.

Methods

This analysis included 50 patients with available samples from the AEGIS-I (ApoA-I Event Reducing in Ischemic Syndromes I) randomized, double-blind, placebo-controlled, phase 2b pharmacokinetic/pharmacodynamic sub-study (2). Patients were randomized to receive four weekly infusions of either placebo (n=16), 2g (n=19) or 6g (n=15) CSL112 post AMI. Blood samples were drawn at baseline and at 2, 4, 6, 12, 24 and 48 hours post the first and fourth infusion for measurement of AER (1) as well as CEC (total, ABCA1 dependent and ABCA1 independent CEC) as previously described (3).

Results

CSL112 infusion increased AER dose-dependently, peaking at 2h (end of infusion) and returning to baseline by 24h post infusion (Figure 1). AER was significantly correlated with CEC (total, ABCA1 dependent and independent), HDL-cholesterol, apoA-I and phosphatidylcholine across all timepoints and similarly after both infusions (Table 1).

Conclusion

Infusion of CSL112 increased AER in a dose-dependent manner post AMI and may represent a clinically amenable biomarker of HDL functionality.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): CSL Ltd, Parkville, Australia Figure 1. Left: Time course data expressed as mean ± SEM and adjusted for baseline prior to each infusion. Using a linear mixed model for repeated measures, the 6g dose increased AER from baseline at timepoints from 2–12 hours (p&lt;0.001), whereas the 2gm dose only increased AER between 2–6 hours (p&lt;0.05). Right: Boxplots showing median, quartiles and min/max of Area Under the Curve (AUC) from 0–24 hours post infusion. Using one-way ANOVA the 6 g dose was significantly higher than placebo (p&lt;0.05).Table 1

Ticagrelor monotherapy after percutaneous coronary intervention in patients with concomitant diabetes mellitus and chronic kidney disease: a TWILIGHT substudy

Background

Diabetes mellitus (DM) and chronic kidney disease (CKD) are established risk factors for cardiovascular events, with patients presenting both conditions being at extremely high risk. P2Y12 inhibitor monotherapy with ticagrelor after a short course of dual antiplatelet therapy has emerged as a bleeding avoidance strategy for high-risk patients undergoing percutaneous coronary intervention (PCI).

Purpose

To investigate ischemic and bleeding outcomes associated with ticagrelor monotherapy versus ticagrelor plus aspirin according to the presence or absence of CKD and DM.

Methods

The TWILIGHT trial enrolled patients undergoing PCI with a drug-eluting stent who fulfilled at least one clinical and one angiographic high-risk criterion. Both DM and CKD (estimated glomerular filtration rate &lt;60 mL/min/1.73m2) were clinical study entry criteria. Following 3 months of ticagrelor plus aspirin, patients who had been adherent to treatment and free from major adverse events were randomly assigned to either aspirin or placebo in addition to ticagrelor for 1 year. The primary endpoint was Bleeding Academic Research Consortium (BARC) type 2, 3 or 5 bleeding. The key secondary endpoint was the composite of all-cause death, myocardial infarction, or stroke. Net adverse clinical events (NACE) were defined as BARC type 3 or 5 bleeding, all-cause death, myocardial infarction, or stroke.

Results

Of the 6273 patients included in the analysis, 8.0% had both CKD and DM (DM+/CKD+), 8.9% had CKD only (DM-/CKD+), 29.0% had DM only (DM+/CKD-), and 52.1% had neither CKD nor DM (DM-/CKD-). At 1-year follow-up, there was a progressive increase in the rates of bleeding and ischemic events according to DM and CKD status (Figure 1). Ticagrelor plus placebo reduced the primary bleeding endpoint as compared with ticagrelor plus aspirin across all study groups, including DM+/CKD+ patients (4.7% vs. 8.7%; HR 0.52, 95% CI 0.25–1.07), with no evidence of heterogeneity (p-interaction=0.68). Similar treatment effects of ticagrelor monotherapy were observed for major BARC type 3 or 5 bleeding (p-interaction=0.17), with DM+/CKD+ patients showing the greatest absolute risk reduction (0.9% vs. 5.1%; HR 0.16, 95% CI 0.04–0.72). The key secondary endpoint was not significantly different between treatment arms across study groups, with the exception of a reduced risk in DM+/CKD- patients receiving ticagrelor monotherapy (p-interaction=0.033). A similar pattern in the DM+/CKD- group was observed for NACE (p-interaction=0.030) (Figure 2).

Conclusions

Among high-risk patients undergoing PCI, ticagrelor monotherapy reduced the risk of clinically relevant and major bleeding without a significant increase in ischemic events as compared with ticagrelor plus aspirin, irrespective of the presence of DM and CKD. Furthermore, ticagrelor monotherapy seemed to be associated with a more favourable net benefit in patients with DM without CKD.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Investigator-initiated grant from AstraZeneca Figure 1. Event rates according to DM/CKD statusFigure 2. Effects of ticagrelor monotherapy

P2Y12 inhibitor monotherapy or dual antiplatelet therapy after coronary revascularisation: individual patient level meta-analysis of randomised controlled trials

OBJECTIVE

To assess the risks and benefits of P2Y₁₂ inhibitor monotherapy compared with dual antiplatelet therapy (DAPT) and whether these associations are modified by patients' characteristics.

DESIGN

Individual patient level meta-analysis of randomised controlled trials.

DATA SOURCES

Searches were conducted in Ovid Medline, Embase, and three websites (www.tctmd.com, www.escardio.org, www.acc.org/cardiosourceplus) from inception to 16 July 2020. The primary authors provided individual participant data.

ELIGIBILITY CRITERIA

Randomised controlled trials comparing effects of oral P2Y₁₂ monotherapy and DAPT on centrally adjudicated endpoints after coronary revascularisation in patients without an indication for oral anticoagulation.

MAIN OUTCOME MEASURES

The primary outcome was a composite of all cause death, myocardial infarction, and stroke, tested for non-inferiority against a margin of 1.15 for the hazard ratio. The key safety endpoint was Bleeding Academic Research Consortium (BARC) type 3 or type 5 bleeding.

RESULTS

The meta-analysis included data from six trials, including 24 096 patients. The primary outcome occurred in 283 (2.95%) patients with P2Y₁₂ inhibitor monotherapy and 315 (3.27%) with DAPT in the per protocol population (hazard ratio 0.93, 95% confidence interval 0.79 to 1.09; P=0.005 for non-inferiority; P=0.38 for superiority; τ²=0.00) and in 303 (2.94%) with P2Y₁₂ inhibitor monotherapy and 338 (3.36%) with DAPT in the intention to treat population (0.90, 0.77 to 1.05; P=0.18 for superiority; τ²=0.00). The treatment effect was consistent across all subgroups, except for sex (P for interaction=0.02), suggesting that P2Y₁₂ inhibitor monotherapy lowers the risk of the primary ischaemic endpoint in women (hazard ratio 0.64, 0.46 to 0.89) but not in men (1.00, 0.83 to 1.19). The risk of bleeding was lower with P2Y₁₂ inhibitor monotherapy than with DAPT (97 (0.89%) v 197 (1.83%); hazard ratio 0.49, 0.39 to 0.63; P<0.001; τ²=0.03), which was consistent across subgroups, except for type of P2Y₁₂ inhibitor (P for interaction=0.02), suggesting greater benefit when a newer P2Y₁₂ inhibitor rather than clopidogrel was part of the DAPT regimen.

CONCLUSIONS

P2Y₁₂ inhibitor monotherapy was associated with a similar risk of death, myocardial infarction, or stroke, with evidence that this association may be modified by sex, and a lower bleeding risk compared with DAPT.

REGISTRATION

PROSPERO CRD42020176853.

Antiplatelet strategies in acute coronary syndromes: design and methodology of an international collaborative network meta-analysis of randomized controlled trials

INTRODUCTION

The optimal choice of oral P2Y<inf>12</inf> receptor inhibitors has the potential to significantly influence outcomes. We seek to compare the safety and efficacy of the three most commonly used oral P2Y<inf>12</inf> receptor inhibitors (clopidogrel, prasugrel, and ticagrelor) in acute coronary syndromes (ACS) via a comprehensive systematic review and network meta-analysis.

EVIDENCE ACQUISITION

In line with the Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines, we performed a comprehensive search for RCTs which compared cardiovascular and hemorrhagic outcomes after use of at least two of the distinct oral P2Y<inf>12</inf> receptor inhibitors (i.e. clopidogrel, prasugrel, and ticagrelor). A search strategy has been designed to systematically search multiple databases, including MEDLINE with PubMed interface, The Cochrane Central Register of Controlled Trials, and Embase. In addition, key inclusion criteria will be trial size of at least 100 patients and at least 1 month of follow-up time. Several prespecified subgroups will be explored, including Asian patients, patients presenting with ST-elevation myocardial infarction, patients of advanced age, and others.

EVIDENCE SYNTHESIS

Exploratory frequentist pairwise meta-analyses will be based primarily on a random-effects method, relying on relative risks (RR) for short-term outcomes and incidence rate ratios (IRR) for long-term outcomes. Inferential frequentist network meta-analysis will be based primarily on a random-effects method, relying on RR and IRR as specified above. Results will be reported as point summary of effect, 95% CI, and P values for effect, and graphically represented using forest plots.

CONCLUSIONS

An international collaborative network meta-analysis has begun to comprehensively analyze the safety and efficacy of prasugrel, ticagrelor and clopidogrel, each on a background of aspirin, for management of patients with ACS. It is our hope that the rigor and breadth of the undertaking described herein will provide novel insights that will inform optimal patient care for patients with ACS treated conservatively, or undergoing revascularization.

Antiplatelet strategies in acute coronary syndromes: design and methodology of an international collaborative network meta-analysis of randomized controlled trials

INTRODUCTION

The optimal choice of oral P2Y<inf>12</inf> receptor inhibitors has the potential to significantly influence outcomes. We seek to compare the safety and efficacy of the three most commonly used oral P2Y<inf>12</inf> receptor inhibitors (clopidogrel, prasugrel, and ticagrelor) in acute coronary syndromes (ACS) via a comprehensive systematic review and network meta-analysis.

EVIDENCE ACQUISITION

In line with the Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines, we performed a comprehensive search for RCTs which compared cardiovascular and hemorrhagic outcomes after use of at least two of the distinct oral P2Y<inf>12</inf> receptor inhibitors (i.e. clopidogrel, prasugrel, and ticagrelor). A search strategy has been designed to systematically search multiple databases, including MEDLINE with PubMed interface, The Cochrane Central Register of Controlled Trials, and Embase. In addition, key inclusion criteria will be trial size of at least 100 patients and at least 1 month of follow-up time. Several prespecified subgroups will be explored, including Asian patients, patients presenting with ST-elevation myocardial infarction, patients of advanced age, and others.

EVIDENCE SYNTHESIS

Exploratory frequentist pairwise meta-analyses will be based primarily on a random-effects method, relying on relative risks (RR) for short-term outcomes and incidence rate ratios (IRR) for long-term outcomes. Inferential frequentist network meta-analysis will be based primarily on a random-effects method, relying on RR and IRR as specified above. Results will be reported as point summary of effect, 95% CI, and P values for effect, and graphically represented using forest plots.

CONCLUSIONS

An international collaborative network meta-analysis has begun to comprehensively analyze the safety and efficacy of prasugrel, ticagrelor and clopidogrel, each on a background of aspirin, for management of patients with ACS. It is our hope that the rigor and breadth of the undertaking described herein will provide novel insights that will inform optimal patient care for patients with ACS treated conservatively, or undergoing revascularization.

288Thrombotic events in bleeding patients treated with andexanet alpha: an ANNEXA-4 sub-study

Background/Introduction

Andexanet alfa (“andexanet”) was developed as a specific reversal agent for patients with major bleeding while using factor Xa (FXa) inhibitors. While thrombotic events (TEs) have been reported in patients receiving andexanet, the scope, nature, and timing of these events have not been fully characterized.

Purpose

The ANNEXA-4 study was a prospective, single-arm, open-label clinical trial that evaluated the safety and efficacy of andexanet in patients with acute major bleeding. In this secondary analysis, the occurrence of TEs was investigated.

Methods

Patients presenting with acute major bleeding within 18 hours after their last dose of FXa inhibitor were treated with andexanet. Safety outcomes, including TEs (reviewed by an adjudication committee), were evaluated at 30 days.

Results

Among 352 patients treated with andexanet, 34 (9.7%) experienced one or more TEs (Table). Strokes and deep vein thromboses were the most frequent TE types. Compared to patients with arterial TEs, patients with venous TEs were more likely to have been originally anticoagulated for venous thromboembolism. Median time to first TE was 10.5 days (Figure); time to event was shorter for arterial TEs than for venous TEs. TEs were nonfatal for most patients. Subgroups by age, bleed type, baseline anti-fXa activity, FXa inhibitor dose, and andexanet dose were not associated with the occurrence of TEs. Of the 34 TE patients, 26 (76.4%) had TEs before restart of any (full or prophylactic) anticoagulation; all first TEs occurred in patients not receiving oral anticoagulation. No TEs occurred after resumption of oral anticoagulation (N=100).

Table 1. Thrombotic event characteristics Characteristic Result (n/N [%]) TE type   Strokes 14/352 (4.0%)   Deep vein thromboses 13/352 (3.7%)   Myocardial infarctions 7/352 (2.0%)   Pulmonary embolisms 5/352 (1.4%)   Transient ischemic attacks 1/352 (0.3%) Bleed type   Intracranial 23/227 (10.1%)   Gastrointestinal 7/90 (7.8%)   Other 4/35 (11.4%) Arterial TEs   Anticoagulated for AF 17/22 (77.3%)   Anticoagulated for VTE 6/22 (27.3%) Venous TEs   Anticoagulated for AF 11/18 (61.1%)   Anticoagulated for VTE 8/18 (44.4%)   Median time to first TE 10.5 days   Arterial 6 days   Venous 15 days Outcome   Fatal 7/34 (20.6%)   Nonfatal 27/34 (79.4%) AF = atrial fibrillation; n = number of patients with TEs; N = total number of patients for each characteristic; TE = thrombotic event; VTE = venous thromboembolism.

Figure 1. Thrombotic Events Over Time

Conclusions

In patients with FXa inhibitor-associated acute major bleeding treated with andexanet, TEs occurred a rate not unexpected given the high thrombotic risk of the population. No factors predictive of TEs were identified. Resumption of anticoagulation was associated with fewer TEs.

Acknowledgement/Funding

Study funded by Portola Pharmaceuticals, Inc.

Beyond Stroke Prevention in Atrial Fibrillation: Exploring Further Unmet Needs with Rivaroxaban

With improved life expectancy and the aging population, the global burden of atrial fibrillation (AF) continues to increase, and with AF comes an estimated fivefold increased risk of ischaemic stroke. Prophylactic anticoagulant therapy is more effective in reducing the risk of ischaemic stroke in AF patients than acetylsalicylic acid or dual-antiplatelet therapy combining ASA with clopidogrel. Non-vitamin K antagonist oral anticoagulants are the standard of care for stroke prevention in patients with non-valvular AF. The optimal anticoagulant strategy to prevent thromboembolism in AF patients who are undergoing percutaneous coronary intervention and stenting, those who have undergone successful transcatheter aortic valve replacement and those with embolic stroke of undetermined source are areas of ongoing research. This article provides an update on three randomized controlled trials of rivaroxaban, a direct, oral factor Xa inhibitor, that are complete or are ongoing, in these unmet areas of stroke prevention: oPen-label, randomized, controlled, multicentre study explorIng twO treatmeNt stratEgiEs of Rivaroxaban and a dose-adjusted oral vitamin K antagonist treatment strategy in patients with Atrial Fibrillation who undergo Percutaneous Coronary Intervention (PIONEER AF-PCI) trial; the New Approach riVaroxaban Inhibition of factor Xa in a Global trial vs Aspirin to prevenT Embolism in Embolic Stroke of Undetermined Source (NAVIGATE ESUS) trial and the Global study comparing a rivAroxaban-based antithrombotic strategy to an antipLatelet-based strategy after transcatheter aortIc vaLve rEplacement to Optimize clinical outcomes (GALILEO) trial. The data from these studies are anticipated to help address continuing challenges for a range of patients at risk of stroke.

Effect of extended-duration thromboprophylaxis on venous thromboembolism and major bleeding among acutely ill hospitalized medical patients: a bivariate analysis

Essentials Anticoagulants prevent venous thromboembolism but may be associated with greater bleeding risks. Bivariate analysis assumes a non-linear relationship between efficacy and safety outcomes. Extended full-dose betrixaban is favorable over standard enoxaparin in bivariate endpoint. Clinicians must weigh efficacy and safety outcomes in decision-making on thromboprophylaxis.

SUMMARY

Background Among acutely ill hospitalized medical patients, extended-duration thromboprophylaxis reduces the risk of venous thromboembolism (VTE), but some pharmacologic strategies have been associated with greater risks of major bleeding, thereby offsetting the net clinical benefit (NCB). Methods To assess the risk-benefit profile of anticoagulation regimens, a previously described bivariate method that does not assume a linear risk-benefit tradeoff and can accommodate different margins for efficacy and safety was performed to simultaneously assess efficacy (symptomatic VTE) and safety (major bleeding) on the basis of data from four randomized controlled trials of extended-duration (30-46 days) versus standard-duration (6-14 days) thromboprophylaxis among 28 227 patients (EXCLAIM, ADOPT, MAGELLAN and APEX trials). Results Extended thromboprophylaxis with full-dose betrixaban (80 mg once daily) was superior in efficacy and non-inferior in safety to standard-duration enoxaparin, and showed a significantly favorable NCB, with a risk difference of - 0.51% (- 0.89% to - 0.10%) in the bivariate outcome. Extended enoxaparin was superior in efficacy and inferior in safety (bivariate outcome: 0.03% [- 0.37% to 0.43%]), whereas apixaban and rivaroxaban were non-inferior in efficacy and inferior in safety (- 0.20% [- 0.49% to 0.17%] and 0.23% [- 0.16% to 0.69%], respectively). Reduced-dose betrixaban did not show a significant difference in either efficacy or safety (0.41% [- 0.85% to 1.94%]). Conclusions In a bivariate analysis that assumes non-linear risk-benefit tradeoffs, extended prophylaxis with full-dose betrixaban was superior to standard-duration enoxaparin, whereas other regimens failed to simultaneously achieve both superiority and non-inferiority with respect to symptomatic VTE and major bleeding in the management of acutely ill hospitalized medical patients.

Low-molecular-weight heparins vs. unfractionated heparin in the setting of percutaneous coronary intervention for ST-elevation myocardial infarction: a meta-analysis

BACKGROUND

The aim of the current study was to perform two separate meta-analyses of available studies comparing low-molecular-weight heparins (LMWHs) vs. unfractionated heparin (UFH) in ST-elevation myocardial infarction (STEMI) patients treated (i) with primary percutaneous coronary intervention (pPCI) or (ii) with PCI after thrombolysis.

METHODS

All-cause mortality was the pre-specified primary endpoint and major bleeding complications were recorded as the secondary endpoints. Relative risk (RR) with a 95% confidence interval (CI) and absolute risk reduction (ARR) were chosen as the effect measure.

RESULTS

Ten studies comprising 16,286 patients were included. The median follow-up was 2 months for the primary endpoint. Among LMWHs, enoxaparin was the compound most frequently used. In the pPCI group, LMWHs were associated with a reduction in mortality [RR (95% CI) = 0.51 (0.41-0.64), P < 0.001, ARR = 3%] and major bleeding [RR (95% CI) = 0.68 (0.49-0.94), P = 0.02, ARR = 2.0%] as compared with UFH. Conversely, no clear evidence of benefits with LWMHs was observed in the PCI group after thrombolysis. Meta-regression showed that patients with a higher baseline risk had greater benefits from LMWHs (r = 0.72, P = 0.02).

CONCLUSIONS

LMWHs were associated with greater efficacy and safety than UFH in STEMI patients treated with pPCI, with a significant relationship between risk profile and clinical benefits. Based on this meta-analysis, LMWHs may be considered as a preferred anticoagulant among STEMI patients undergoing pPCI.

Rivaroxaban versus placebo in patients with acute coronary syndromes (ATLAS ACS-TIMI 46): a randomised, double-blind, phase II trial

BACKGROUND

Rivaroxaban is an oral direct factor Xa inhibitor that has been effective in prevention of venous thromboembolism in patients undergoing elective orthopaedic surgery. However, its use after acute coronary syndromes has not been investigated. In this setting, we assessed the safety and efficacy of rivaroxaban and aimed to select the most favourable dose and dosing regimen.

METHODS

In this double-blind, dose-escalation, phase II study, undertaken at 297 sites in 27 countries, 3491 patients stabilised after an acute coronary syndrome were stratified on the basis of investigator decision to use aspirin only (stratum 1, n=761) or aspirin plus a thienopyridine (stratum 2, n=2730). Participants were randomised within each strata and dose tier with a block randomisation method at 1:1:1 to receive either placebo or rivaroxaban (at doses 5-20 mg) given once daily or the same total daily dose given twice daily. The primary safety endpoint was clinically significant bleeding (TIMI major, TIMI minor, or requiring medical attention); the primary efficacy endpoint was death, myocardial infarction, stroke, or severe recurrent ischaemia requiring revascularisation during 6 months. Safety analyses included all participants who received at least one dose of study drug; efficacy analyses were by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00402597.

FINDINGS

Three patients in stratum 1 and 26 in stratum 2 never received the study drug. The risk of clinically significant bleeding with rivaroxaban versus placebo increased in a dose-dependent manner (hazard ratios [HRs] 2.21 [95% CI 1.25-3.91] for 5 mg, 3.35 [2.31-4.87] for 10 mg, 3.60 [2.32-5.58] for 15 mg, and 5.06 [3.45-7.42] for 20 mg doses; p<0.0001). Rates of the primary efficacy endpoint were 5.6% (126/2331) for rivaroxaban versus 7.0% (79/1160) for placebo (HR 0.79 [0.60-1.05], p=0.10). Rivaroxaban reduced the main secondary efficacy endpoint of death, myocardial infarction, or stroke compared with placebo (87/2331 [3.9%] vs 62/1160 [5.5%]; HR 0.69, [95% CI 0.50-0.96], p=0.0270). The most common adverse event in both groups was chest pain (248/2309 [10.7%] vs 118/1153 [10.2%]).

INTERPRETATION

The use of an oral factor Xa inhibitor in patients stabilised after an acute coronary syndrome increases bleeding in a dose-dependent manner and might reduce major ischaemic outcomes. On the basis of these observations, a phase III study of low-dose rivaroxaban as adjunctive therapy in these patients is underway.

FUNDING

Johnson & Johnson Pharmaceutical Research & Development and Bayer Healthcare AG.

Early glycoprotein IIb-IIIa inhibitors in primary angioplasty (EGYPT) cooperation: an individual patient data meta-analysis

Background:

Even though time-to-treatment has been shown to be a determinant of mortality in primary angioplasty, the potential benefits from early pharmacological reperfusion by glycoprotein (Gp) IIb–IIIa inhibitors are still unclear. The aim of this meta-analysis was to combine individual data from all randomised trials conducted on facilitated primary angioplasty by the use of early Gp IIb–IIIa inhibitors.

Methods and results:

The literature was scanned by formal searches of electronic databases (MEDLINE, EMBASE) from January 1990 to October 2007. All randomised trials on facilitation by the early administration of Gp IIb–IIIa inhibitors in ST-segment elevation myocardial infarction (STEMI) were examined. No language restrictions were enforced. Individual patient data were obtained from 11 out of 13 trials, including 1662 patients (840 patients (50.5%) randomly assigned to early and 822 patients (49.5%) to late Gp IIb–IIIa inhibitor administration). Preprocedural Thrombolysis in Myocardial Infarction Study (TIMI) grade 3 flow was more frequent with early Gp IIb–IIIa inhibitors. Postprocedural TIMI 3 flow and myocardial blush grade 3 were higher with early Gp IIb–IIIa inhibitors but did not reach statistical significance except for abciximab, whereas the rate of complete ST-segment resolution was significantly higher with early Gp IIb–IIIa inhibitors. Mortality was not significantly different between groups, although early abciximab demonstrated improved survival compared with late administration, even after adjustment for clinical and angiographic confounding factors.

Conclusions:

This meta-analysis shows that pharmacological facilitation with the early administration of Gp IIb–IIIa inhibitors in patients undergoing primary angioplasty for STEMI is associated with significant benefits in terms of preprocedural epicardial recanalisation and ST-segment resolution, which translated into non-significant mortality benefits except for abciximab.

Determinants of improvement in epicardial flow and myocardial perfusion for ST elevation myocardial infarction; insights from TIMI 14 and InTIME-II

BACKGROUND

When evaluating new reperfusion regimens for ST elevation MI, it is important to adjust for factors that influence the likelihood of achieving normal epicardial flow and complete ST resolution.

METHODS AND RESULTS

A total of 610 patients from TIMI 14 contributed to the angiographic analyses. The electrocardiographic analyses were based on 544 patients from TIMI 14 and 763 patients from InTIME-II. For each hour from onset of symptoms to initiation of pharmacological reperfusion, the odds of achieving TIMI 3 flow at 90 min or complete ST resolution at 60-90 min decreased significantly (P=0.03). Anterior location of infarction was associated with a reduction in the odds of achieving TIMI 3 flow or complete ST resolution. The use of abciximab as part of the reperfusion regimen significantly increased the odds of TIMI 3 flow (P=0.01) and ST resolution (P<0.001). The fibrinolytic administered (alteplase, reteplase, lanoteplase) did not influence the odds of TIMI 3 flow or ST resolution after adjusting for time to treatment, infarct location, and use of abciximab.

CONCLUSIONS

The influence of time from symptoms on epicardial flow and STRES reinforces the need for increased efforts to reduce treatment delays in patients with ST elevation MI. The significant benefits of abciximab with respect to facilitation of epicardial and myocardial reperfusion are evident even after adjusting for time to treatment and infarct location. To adjust for determinants of success of reperfusion regimens, phase II trials evaluating new drug combinations should consider using a randomization scheme that stratifies patients based on infarct location and time from symptoms.

Use of reperfusion therapies in elderly patients with acute myocardial infarction

Almost one-third of patients with acute myocardial infarction (AMI) are aged >75 years, and this proportion is expected to increase as the population ages. Mortality and complication rates are particularly high in the elderly, yet reperfusion therapies, including thrombolysis and primary percutaneous transluminal coronary angioplasty (PTCA), are under-utilised among eligible patients. There is a concern, whether real or perceived, that the risks of such therapies may outweigh the potential benefits. Presently, there are no randomised clinical trials of thrombolytic therapy in the elderly that definitively assess its efficacy in patients aged >75 years. In the meta-analysis of randomised trials by the Fibrinolytic Therapy Trialists, thrombolysis was associated with a mortality reduction among patients aged >75 years, though this reduction did not meet formal statistical significance. Because the point estimates for mortality reduction were in the direction that favoured use of thrombolytic therapy, the American Heart Association/American College of Cardiology AMI guidelines recommend thrombolysis as a Class 2a therapy in this age group. Observational studies using data from the Cooperative Cardiovascular Project database and the National Registry of Myocardial Infarction have recently cast some doubt on the benefit of thrombolysis among the elderly, but definitive answers from a randomised trial are still lacking. Meanwhile, primary PTCA, which has been compared to thrombolysis in both trial and observational settings, appears to offer the mortality benefit of reperfusion with lower stroke rates. Since primary PTCA is not widely available, efforts must be made to maximise available therapies in the elderly. Early diagnosis is essential, as is prompt reperfusion among eligible patients, since delay is so strongly associated with mortality with both thrombolysis and PTCA. Finally, newer, more fibrin-specific thrombolytics may decrease the bleeding risk associated with thrombolytic therapy.

Double-blind, randomized trial of an anti-CD18 antibody in conjunction with recombinant tissue plasminogen activator for acute myocardial infarction: limitation of myocardial infarction following thrombolysis in acute myocardial infarction (LIMIT AMI) study

BACKGROUND

Inhibition of leukocyte adhesion can reduce myocardial infarct size in animals. This study was designed to define the safety and efficacy of a recombinant, humanized, monoclonal antibody to the CD18 subunit of the beta2 integrin adhesion receptors (rhuMAb CD18), in reducing infarct size in patients treated with a thrombolytic agent.

METHODS AND RESULTS

The Limitation of Myocardial Infarction following Thrombolysis in Acute Myocardial Infarction Study (LIMIT AMI) was a randomized, double-blind, placebo-controlled, multicenter study conducted in 60 centers in the United States and Canada. A total of 394 subjects who presented within 12 hours of symptom onset with ECG findings (ST-segment elevation) consistent with AMI were treated with recombinant tissue plasminogen activator and were also given an intravenous bolus of 0.5 or 2.0 mg/kg rhuMAb CD18 or placebo. Coronary angiography was performed at 90 minutes, 12-lead ECGs were obtained at baseline, 90, and 180 minutes, and resting sestamibi scans were performed at >/=120 hours. Adjunctive angioplasty and use of glycoprotein IIb/IIIa antiplatelet agents at the time of angiography were discretionary. There were no treatment effects on coronary blood flow, infarct size, or the rate of ECG ST-segment elevation resolution, despite the expected induction of peripheral leukocytosis. A slight trend toward an increase in bacterial infections was observed with rhuMAb CD18 (P=0.33).

CONCLUSIONS

RhuMAb CD18 was well tolerated but not effective in modifying cardiac end points.

Safety of the weight-adjusted dosing regimen of tenecteplase in the ASSENT-Trial

The results of the ASsessment of Safety and Efficacy of a New Thrombolytic agent (ASSENT-2) trial revealed that tenecteplase (TNK) is equivalent to tissue plasminogen activator (t-PA) for treating myocardial infarction. Because careful consideration of safety is important with all agents, including the newer bolus therapies, and across a range of doses, this study evaluated the safety of TNK compared with t-PA across a range of weight and dose categories. The 5 doses of TNK ranged from 30 to 50 mg and were adjusted for estimated weight. Rates of death and intracranial hemorrhage were determined among patients receiving TNK and t-PA in ASSENT-2, stratified by categories of estimated weight corresponding to each TNK dose. Respective rates of death with TNK versus t-PA were not significantly different in any estimated weight category: <60 kg (12.54% vs 11.46%), 60 to 69 kg (8.22% vs. 8.97%), 70 to 79 kg (5.57% vs 5.48%), 80 to 89 kg (4.66% vs 5.36%), and > or =90 kg (4.91% vs. 3.96%, all p > or =0.26). Respective rates of intracranial hemorrhage were also not significantly different: <60 kg (2.20% vs. 2.29%), 60 to 69 kg (0.97% vs. 1.33%), 70 to 79 kg (1.15% vs. 1.10%), 80 to 89 kg (0.73% vs 0.49%), and > or =90 kg (0.47% vs 0.47%, all p > or =0.33). Adjustment for small baseline differences in this randomized sample did not change the results. Thus, across the range of estimated weight categories corresponding to each TNK dose, TNK is as safe and effective as t-PA.

Early coronary intervention following pharmacologic therapy for acute myocardial infarction (the combined TIMI 10B-TIMI 14 experience)

Earlier studies have suggested that immediate percutaneous coronary intervention (PCI) following thrombolytic therapy for acute myocardial infarction (AMI) is associated with an increase in adverse events and that routine PCI in this setting has offered no advantage over a conservative strategy. To reassess this issue in a more recent era, we evaluated 1,938 patients from the Thrombolysis in Myocardial Infarction (TIMI) 10B and 14 trials of AMI. Patients in TIMI 10B were randomized to receive tissue plasminogen activator or TNK tissue plasminogen activator, whereas patients in TIMI 14B trial were randomized to receive thrombolytic therapy with or without abciximab. All patients underwent angiography 90 minutes after receiving pharmacologic therapy. Patients who underwent PCI were classified as having undergone a rescue procedure (TIMI 0 or 1 flow at 90 minutes), an adjunctive procedure (TIMI 2 or 3 flow at 90 minutes), or a delayed procedure (performed >150 minutes after symptom onset, median of 2.75 days). Among patients with TIMI 0 or 1 flow, there was a trend for lower 30-day mortality among patients who underwent rescue PCI than among those who did not (6% vs 17%, p = 0.01, adjusted p = 0.28). Patients who underwent adjunctive PCI had similar 30-day mortality and/or reinfarction as those who underwent delayed PCI. In a multivariate model both had lower 30-day mortality and/or reinfarction than patients with "successful thrombolysis" (i.e., TIMI 3 flow at 90 minutes) who did not undergo revascularization (p = 0.02). Thus, early PCI following AMI is associated with excellent outcomes. Randomized trials of an early invasive strategy following thrombolysis are warranted.

Use of risk stratification to identify patients with unstable angina likeliest to benefit from an invasive versus conservative management strategy

OBJECTIVES

This study was designed to determine whether patient characteristics collected at presentation can identify which patients benefit from immediate coronary angiography and revascularization.

BACKGROUND

Risk stratification may offer a method for identifying which patients with unstable angina or non-Q-wave myocardial infarction (NQMI) are likeliest to benefit from invasive management strategies.

METHODS

The analysis was based on data from a randomized controlled trial that enrolled 1,473 patients presenting with unstable angina or NQMI who were randomly assigned to an early invasive or early conservative (medical) management strategy. We constructed a risk-stratification score for each patient based on adjusted odds ratios for clinical variables likely to predict adverse outcomes. We stratified all trial subjects by their risk scores and studied the rates of death or myocardial infarction (MI) of the early invasive management strategy in each stratum.

RESULTS

The final multivariate model included older age, ST segment depression on presentation, history of complicated angina before presentation, and elevation in baseline creatine kinase-MB fraction. Although patients with a higher risk score had an increased rate of death or MI within 42 days and 365 days (p < 0.001) in both management strategies, early invasive management for patients in the high and very high risk categories was associated with a lower rate of death or MI within 42 days compared with conservative management. No such benefit was seen in patients in the larger group of patients in the very low, low or moderate risk categories (p = 0.03 for the interaction between risk category and management assignment).

CONCLUSIONS

Risk stratification may be an effective method for identifying those patients with unstable angina or NQMI most likely to benefit from early invasive management. Selective use of early invasive management can have a substantial impact in reducing morbidity and mortality in higher risk patients, but may not be warranted in lower risk patients.

Issues in the assessment of the safety and efficacy of tenecteplase (TNK-tPA)

While thrombolytic agents have demonstrated improved mortality over the use of placebo, this has come at the expense of bleeding complications such as intracranial hemorrhage (ICH). Tenecteplase (TNK-tPA) is a novel thrombolytic agent engineered to improve upon the ease of use and safety of alteplase (t-PA). Given its longer half-life, TNK-tPA can be administered as a single bolus. The dosing of TNK-tPA has been weight optimized to enhance both safety and efficacy outcomes. Weight-optimized TNK-tPA dosing requires body weight estimation, which may introduce the potential for medication error. However, data from TNK-tPA clinical trials suggest that body weight estimates can err by up to 20 kg (44 lb) without an increased risk of ICH or death. Furthermore, the results of TNK-tPA clinical trials showed that even at the highest weight-optimized dosage of 50 mg, ICH rates were among the lowest reported in clinical trials of thrombolytics for acute myocardial infarction. In elderly female patients of low body weight, the use of weight-optimized TNK-tPA lowered the risk of ICH compared with the use of t-PA, expanding the potential use of thrombolytics to this high-risk patient population. Tenecteplase has demonstrated clinical equivalence to t-PA, but with a wider therapeutic margin of safety.

Early noninvasive detection of failed epicardial reperfusion after fibrinolytic therapy

Available noninvasive techniques for identifying patients with failed epicardial reperfusion after fibrinolytic therapy are limited by poor accuracy. It is unknown whether combining multiple noninvasive predictors would improve diagnostic accuracy and facilitate identification of candidates for rescue percutaneous coronary intervention. In the Thrombolysis In Myocardial Infarction (TIMI) 14 trial, we evaluated the ability of ST-segment resolution (n = 606), chest pain resolution (n = 859), and the ratio of 60-minute/baseline serum myoglobin (n = 308) to identify patients with angiographic evidence of failed reperfusion 90 minutes after fibrinolysis. Three criteria were prospectively defined: <50% ST resolution at 90 minutes, presence of chest pain at the time of angiography, and myoglobin ratio <4. Patients who met any individual criterion were more likely to have less than TIMI 3 flow and an occluded infarct-related artery (TIMI 0/1 flow) than those who did not meet the criterion (p <0.005 for each). When the 3 criteria were used together (n = 169), patients who satisfied 0 (n = 29), 1 (n = 68), 2 (n = 51), or 3 (n = 21) of the criteria had a 17%, 24%, 35%, and 76% probability of failing to achieve TIMI 3 flow (p <0.0001 for trend), a 0%, 6%, 18%, and 57% probability of an occluded infarct-related artery (p <0.0001 for trend), and a 0%, 1.5%, 2.0%, and 9.5% rate of 30-day mortality (p = 0.05 for trend), respectively. Use of the criteria in combination increased positive predictive values without decreasing negative predictive values. In conclusion, ST-segment resolution, chest pain resolution, and early washout of serum myoglobin can be used in combination to aid in the early noninvasive identification of candidates for rescue percutaneous coronary intervention.

Myoglobin levels at 12 hours identify patients at low risk for 30-day mortality after thrombolysis in acute myocardial infarction: a Thrombolysis in Myocardial Infarction 10B substudy

OBJECTIVE

We sought to identify, by use of serum cardiac markers, patients at low risk for 30-day mortality after ST-segment elevation myocardial infarction.

BACKGROUND

Baseline cardiac markers are currently used to identify patients at increased risk for short-term events. We hypothesized that serum markers measured after treatment could identify patients at low risk for 30-day mortality.

METHODS

A total of 839 patients from the Thrombolysis in Myocardial Infarction (TIMI) 10B study had myoglobin, cardiac-specific troponin-I, creatine kinase (CK)-MB measurements at the following time points; baseline, 90 minutes, and 3 and 12 hours after thrombolysis. By use of receiver operating characteristic analysis, thresholds were derived to predict 30-day mortality with at least 95% negative predictive value.

RESULTS

Ninety minutes after thrombolysis myoglobin was superior to troponin-I or CK-MB in identifying patients at low risk for mortality. The 30-day mortality for 12-hour myoglobin < or = 239 ng/mL was 1.4% compared with 9.1% for levels > 239 ng/mL (P < .001). For 12-hour troponin-I (threshold 81.5 ng/mL), mortality was 1.9% versus 6.6% (P = .001) if above threshold; similarly for CK-MB at 12 hours (threshold 191 ng/mL) it was 3.3% versus 7.9% (P = .02). Multivariate analysis of baseline and posttreatment cardiac markers, age, sex, infarct artery location, and 90-minute TIMI flow grade identified only 12-hour myoglobin among the cardiac markers as independently predicting a low 30-day mortality (odds ratio 0.11, 95% confidence interval 0.02-0.50, P < .004).

CONCLUSION

Serum cardiac markers can identify greater than two thirds of patients at low risk for 30-day mortality. A low 12-hour myoglobin level (< or = 239 ng/mL in this substudy) identifies such patients at low risk and could potentially assist in early risk stratification and triage after ST-segment elevation myocardial infarction.

Comparison of early invasive and conservative strategies in patients with unstable coronary syndromes treated with the glycoprotein IIb/IIIa inhibitor tirofiban

BACKGROUND

There is continued debate as to whether a routine, early invasive strategy is superior to a conservative strategy for the management of unstable angina and myocardial infarction without ST-segment elevation.

METHODS

We enrolled 2220 patients with unstable angina and myocardial infarction without ST-segment elevation who had electrocardiographic evidence of changes in the ST segment or T wave, elevated levels of cardiac markers, a history of coronary artery disease, or all three findings. All patients were treated with aspirin, heparin, and the glycoprotein IIb/IIIa inhibitor tirofiban. They were randomly assigned to an early invasive strategy, which included routine catheterization within 4 to 48 hours and revascularization as appropriate, or to a more conservative (selectively invasive) strategy, in which catheterization was performed only if the patient had objective evidence of recurrent ischemia or an abnormal stress test. The primary end point was a composite of death, nonfatal myocardial infarction, and rehospitalization for an acute coronary syndrome at six months.

RESULTS

At six months, the rate of the primary end point was 15.9 percent with use of the early invasive strategy and 19.4 percent with use of the conservative strategy (odds ratio, 0.78; 95 percent confidence interval, 0.62 to 0.97; P=0.025). The rate of death or nonfatal myocardial infarction at six months was similarly reduced (7.3 percent vs. 9.5 percent; odds ratio, 0.74; 95 percent confidence interval, 0.54 to 1.00; P<0.05).

CONCLUSIONS

In patients with unstable angina and myocardial infarction without ST-segment elevation who were treated with the glycoprotein IIb/IIIa inhibitor tirofiban, the use of an early invasive strategy significantly reduced the incidence of major cardiac events. These data support a policy involving broader use of the early inhibition of glycoprotein IIb/IIIa in combination with an early invasive strategy in such patients.

Combination therapy with abciximab reduces angiographically evident thrombus in acute myocardial infarction: a TIMI 14 substudy

BACKGROUND

Use of abciximab in combination with administration of thrombolytics has been shown to improve epicardial and microvascular coronary blood flow in acute myocardial infarction (AMI). As a potential mechanism, we hypothesized that combination therapy would reduce angiographically evident thrombus (AET) and would increase lumen diameter compared with thrombolytic monotherapy.

METHODS AND RESULTS

Patients who received combination therapy in TIMI 14 (low-dose thrombolytic plus abciximab, n=732) were compared with patients who received thrombolytic monotherapy without abciximab in the TIMI 4, 10A, 10B, and 14 trials (n=1662). Thrombus burden was assessed 90 minutes after treatment, and quantitative angiography was performed in an angiographic core laboratory by investigators blinded to treatment assignment. The frequency of AET was reduced in patients who received abciximab combination therapy compared with thrombolytic monotherapy (26.6% versus 35.4%, P<0.001). Similar findings were observed when the analysis was restricted to patients with patent arteries (14.7% versus 20.8%, P=0.001). Residual percent diameter stenosis at 90 minutes was also improved in the abciximab therapy group both in patent arteries (64.6+/-16.6 versus 68.3+/-14.8, P<0.001) and between patent and occluded arteries (69.3+/-19.5 versus 73.8+/-17.9, P<0.001). The absence of AET was associated with an increased frequency of >70% ST-segment resolution by 90 minutes (37.2%, 110/296 versus 18.9%, 54/286, P<0.001).

CONCLUSIONS

Compared with thrombolytic monotherapy, combination therapy with abciximab reduces AET, which in turn is associated with reduced residual stenosis and improved ST-segment resolution in AMI. These data provide a pathophysiological link between platelet inhibition, reduced thrombus, and improvements in both epicardial and microvascular perfusion in AMI.

Impact of contrast agent type (ionic versus nonionic) used for coronary angiography on angiographic, electrocardiographic, and clinical outcomes following thrombolytic administration in acute myocardial infarction

The goal of this study was to examine the relationship between contrast agent type (ionic vs. nonionic) and angiographic, electrocardiographic, and clinical outcomes after thrombolytic administration. Ionic or nonionic contrast agents were selected in a nonrandomized fashion for 90-min angiography and percutaneous coronary intervention (PCI) following thrombolytic administration in the TIMI 14 trial [tissue plasminogen activator (tPA) or reteplase (rPA) vs. low-dose lytic + abciximab]. There was no relationship between contrast agent type and overall patency, rate of TIMI grade 3 flow, or corrected TIMI frame counts (CTFCs) in open culprit arteries and in post-PCI patency rates or post-PCI CTFCs. In patients treated with ionic contrast, ejection fractions at 90 min were slightly but significantly lower (56.2 +/- 16.5, n = 122, vs. 59.8 +/- 14.4, n = 322; P = 0.02), chest pain duration was longer (2.8 +/- 4.1 hr, n = 255, vs. 1.7 +/- 3.6, n = 550; P = 0.0003), and complete ST segment resolution was less frequent (41.5% vs. 50.8%; P = 0.04). While there was no difference in epicardial blood flow, ionic contrast agent use was associated with poorer ST segment resolution, longer chest pain duration, and poorer ejection fractions, perhaps as a result of microvascular dysfunction.

Abciximab and early adjunctive percutaneous coronary intervention are associated with improved ST-segment resolution after thrombolysis: Observations from the TIMI 14 Trial

BACKGROUND

Percutaneous coronary intervention (PCI) improves clinical outcomes in selected patients with failed thrombolysis but has not been proven to benefit patients who achieve a patent infarct-related artery. Even after successful epicardial reperfusion, myocardial perfusion may be inadequate. We sought to evaluate whether a strategy that uses a reperfusion regimen containing abciximab and a reduced-dose thrombolytic agent (combination therapy), followed by early adjunctive PCI, would result in improved myocardial perfusion, as assessed by ST-segment resolution.

METHODS

ST resolution from 90 to 180 minutes after therapy was calculated for all 410 patients from the TIMI 14 trial who had evaluable electrocardiograms at both time points and who were treated with alteplase or reteplase. Patients were grouped according to whether they were treated with combination therapy or full-dose thrombolytic agent alone and whether they underwent PCI between the 90- and 180-minute electrocardiographic measurements.

RESULTS

Among 105 patients who underwent adjunctive PCI between 90 and 180 minutes, mean ST resolution from 90 to 180 minutes was significantly greater in those who had received combination therapy versus those who had received full-dose thrombolytic alone (54% vs 8%; P =.002). Among 241 patients with TIMI grade 3 flow in the infarct-related artery at 90 minutes, adjunctive PCI significantly improved mean ST resolution in patients who had been treated with combination therapy (57% [PCI] vs 24% [no PCI]; P =.006), but PCI did not have this effect in patients who had received thrombolytic therapy alone (1% [PCI] vs 10% [no PCI]; P =.70). In a multivariate model controlling for factors that would be expected to independently influence 90- to 180-minute ST resolution, abciximab treatment remained significantly associated with greater ST resolution (P =.008).

CONCLUSIONS

A strategy that uses a combination reperfusion regimen that includes abciximab, followed by early adjunctive PCI, is associated with greater ST-segment resolution, which may reflect enhanced tissue level and microvascular perfusion. Future studies should evaluate prospectively the clinical efficacy of this strategy.

Can we replace the 90-minute thrombolysis in myocardial infarction (TIMI) flow grades with those at 60 minutes as a primary end point in thrombolytic trials? TIMI Study Group

The establishment of patency (Thrombolysis In Myocardial Infarction [TIMI] grade 2 or 3 flow) and/or TIMI grade 3 flow at 60 minutes after thrombolytic administration is both a univariate and multivariate predictor of in-hospital and 30-day mortality, and the odds ratios for mortality are nearly identical for TIMI grade 3 flow at 60 and 90 minutes. Thus, the 60-minute angiographic end point appears to be a valid alternative to that at 90 minutes and may permit earlier decisions regarding post-thrombolytic intervention.

Determination of a weight-adjusted dose of TNK-tissue plasminogen activator

BACKGROUND

TNK-tissue plasminogen activator (TNK-tPA) is a potent new thrombolytic agent for treatment of acute myocardial infarction. TNK-tPA was evaluated in 4214 patients in two dose-ranging trials (Thrombolysis in Myocardial Infarction [TIMI] 10B and Assessment of the Safety and Efficacy of a New Thrombolytic Agent [ASSENT] I). This article describes the rationale for the weight-adjusted dosing regimen of TNK-tPA that was selected for evaluation in the large phase III clinical trial ASSENT II.

METHODS

Weight-based analyses were conducted with data from both the angiographic TIMI 10B trial, which compared TNK-tPA in doses of 30 mg, 40 mg, and 50 mg with the accelerated regimen of tPA in 889 patients, and the ASSENT I trial, which evaluated the safety of TNK-tPA in doses of 30 mg, 40 mg, and 50 mg in 3301 patients. Graphic and statistical analytic methods were used to assess relationships between weight and efficacy or safety measurements.

RESULTS

The plasma clearance, initial plasma concentrations, and plasma steady-state volume of distribution all increased with decreasing body weight (all P<.001). The corrected TIMI frame count decreased (flow was faster) (P =.001) and the TIMI grade 3 flow increased with an increasing weight-standardized dose of TNK-tPA (P<.008). Mortality was inversely related to dose, but this relationship was not statistically significant. There was no clear relationship between intracranial hemorrhage and dose and weight. Serious bleeding events increased with increasing weight-standardized dose (P<.02).

CONCLUSIONS

On the basis of these analyses, a weight-adjusted dosing regimen was devised for TNK-tPA that included five dosing increments and was based on a target weight-standardized dose of 0.53 mg/kg.

Impact of injections during diagnostic coronary arteriography on coronary patency in the setting of acute myocardial infarction from the TIMI trials. Thrombolysis In Myocardial Infarction

The mechanical force of injection at 90 minutes opens 13.4% of occluded arteries, but overall, only 2.4% of all culprit arteries (already open and occluded combined) are opened. Thus, although some arteries are opened by the force of hand injection, the frequency of mechanical opening among all arteries is low, and hand injections appear to alter current 80% patency rates by approximately 2.5%.

Global impairment of coronary blood flow in the setting of acute coronary syndromes (a RESTORE substudy). Randomized Efficacy Study of Tirofiban for Outcomes and Restenosis

Acute coronary syndromes result in a global impairment of coronary blood flow with nonculprit artery blood flow being associated with culprit artery flow and vice versa. Improvements in nonculprit artery flow are related to improvements in culprit artery flow after percutaneous intervention; nonculprit arteries with abnormal flow sustain greater improvements in their flow after culprit artery intervention.

Combination reperfusion therapy with abciximab and reduced dose reteplase: results from TIMI 14. The Thrombolysis in Myocardial Infarction (TIMI) 14 Investigators

Aims Abciximab has previously been shown to enhance thrombolysis and improve myocardial perfusion when combined with reduced doses of alteplase. The purpose of the reteplase phase of TIMI 14 was to evaluate the effects of abciximab when used in combination with a reduced dose of reteplase for ST-elevation myocardial infarction. Methods and Results Patients (n=299) with ST-elevation myocardial infarction were treated with aspirin and randomized to a control arm with standard dose reteplase (10+10 U given 30 min apart) or abciximab (bolus of 0.25 mg. kg(-1)and 12-h infusion of 0.125 microg. kg(-1). min(-1)) in combination with reduced doses of reteplase (5+5 U or 10+5 U). Control patients received standard weight-adjusted heparin (bolus of 70 U. kg(-1); infusion of 15 U. kg(-1). h(-1)), while each of the combination arms with abciximab and reduced dose reteplase received either low dose heparin (bolus of 60 U. kg(-1); infusion of 7 U. kg(-1). h(-1)) or very low dose heparin (bolus of 30 U. kg(-1); infusion of 4 U. kg(-1). h(-1)). The rate of TIMI 3 flow at 90 min was 70% for patients treated with 10+10 U of reteplase alone (n=87), 73% for those treated with 5+5 U of reteplase with abciximab (n=88), and 77% for those treated with 10+5 U of reteplase with abciximab (n=75). Complete (>/=70%) ST resolution at 90 min was seen in 56% of patients receiving a reduced dose of reteplase in combination with abciximab compared with 48% of patients receiving reteplase alone. Conclusions Reduced doses of reteplase when administered in combination with abciximab were associated with higher TIMI 3 flow rates than reported previously for reduced doses of reteplase without abciximab and were at least as high as for full dose reteplase alone