Adjusted Indirect Meta-Analysis of Aspirin Plus Warfarin at International Normalized Ratios 2 to 3 Versus Aspirin Plus Clopidogrel After Acute Coronary Syndromes

Direct Oral Anticoagulants in Addition to Antiplatelet Therapy for Secondary Prevention After Acute Coronary Syndromes: A Systematic Review and Meta-analysis

Importance

Patients with acute coronary syndrome (ACS) remain at high risk for experiencing recurrent ischemic events. Direct oral anticoagulants (DOAC) have been proposed for secondary prevention after ACS.

Objective

To evaluate the safety and efficacy of DOAC in addition to antiplatelet therapy (APT) after ACS, focusing on treatment effects stratified by baseline clinical presentation (non-ST-segment elevation ACS [NSTE-ACS] vs ST-segment elevation myocardial infarction [STEMI]).

Data Sources

PubMed, Embase, BioMedCentral, Google Scholar, and the Cochrane Central Register of Controlled Trials were searched from inception to March 1, 2017.

Study Selection

Randomized clinical trials on DOAC after ACS were evaluated for inclusion. Overall, 473 studies were screened, 19 clinical trials were assessed as potentially eligible, and 6 were included in the meta-analysis.

Data Extraction and Synthesis

Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were used to abstract data and assess quality and validity. The risk of bias tool, version 2.0 (Cochrane) was used for risk of bias assessment. Data were pooled using random-effects models.

Main Outcomes and Measures

The prespecified primary efficacy end point was the composite of cardiovascular death, myocardial infarction, and stroke. The prespecified primary safety end point was major bleeding.

Results

Six trials that included 29 667 patients were identified (14 580 patients [49.1%] with STEMI and 15 036 [50.7%] with NSTE-ACS). The primary efficacy end point risk was significantly lower in patients who were treated with DOAC as compared with APT alone (odds ratio [OR], 0.85; 95% CI, 0.77-0.93; P < .001). This benefit was pronounced in patients with STEMI (OR, 0.76; 95% CI, 0.66-0.88; P < .001), while no significant treatment effect was observed in patients with NSTE-ACS (OR, 0.92; 95% CI, 0.78-1.09; P = .36; P for interaction = .09). With respect to safety, DOACs were associated with a higher risk of major bleeding as compared with APT alone (OR, 3.17; 95% CI, 2.27-4.42; P < .001), with consistent results in patients with STEMI (OR, 3.45; 95% CI, 1.95-6.09; P < .001) and NSTE-ACS (OR, 2.19; 95% CI, 1.38-3.48; P < .001; P for interaction = .23).

Conclusions and Relevance

To our knowledge, these findings are the first evidence to support differential treatment effects of DOAC in addition to APT according to ACS baseline clinical presentation. In patients with NSTE-ACS, the risk-benefit profile of DOAC appears unfavorable. Conversely, DOAC in addition to APT might represent an attractive option for patients with STEMI.

Anticoagulation in Patients with Ischaemic Heart Disease and Peripheral Arterial Disease: Clinical Implications of COMPASS Study

Patients with established cardiovascular disease may suffer further cardiovascular events, despite receiving optimal medical treatment. Although platelet inhibition plays a central role in the prevention of new events, the use of anticoagulant therapies to reduce events in atheromatous disease has, until recently, been overlooked. The recent Rivaroxaban for the Prevention of Major Cardiovascular Events in Coronary or Peripheral Artery Disease (COMPASS) study showed an important reduction in cardiovascular events without increasing the risk of fatal and intracranial bleeding when using rivaroxaban, a novel oral anticoagulant, combined with aspirin. This article reviews the available evidence regarding the use of anticoagulant therapies for prevention of cardiovascular events, the results of the COMPASS study and how these results may affect patient management in everyday clinical practice.

High platelet reactivity – the challenge of prolonged anticoagulation therapy after ACSI

Despite dual antiplatelet therapy (DAPT), one-year event rates after acute coronary syndrome (ACS) vary from 9–12%. The development of novel oral anticoagulants (NOAC) without a need for monitoring has initiated renewed interest for prolonged adjunctive anticoagulation. Importantly, the cornerstone of treatment after ACS consists of long-term DAPT. In that context, the NOACs have only been tested as adjunctive therapy. Of all new agents, only rivaroxaban –in a substantially lower dose than used for atrial fibrillation– has been demonstrated to improve outcome, albeit at the cost of bleeding. In selected cases, adjunctive therapy with dose-adjusted vitamin-K antagonists (international normalized ratio [INR] 2.0–3.0) can be considered as well. These two strategies of prolonged anticoagulation can be considered in case of ‘high platelet reactivity’, i.e. in patients at high risk of recurrent thrombotic events despite DAPT. Both during admission and after discharge for ACS, the use of NOACs in doses indicated for atrial fibrillation is strictly contra-indicated in patients on DAPT. In case of post-discharge anticoagulation therapy for atrial fibrillation, patients should preferably receive vitamin-K antagonists (INR 2.0–3.0), with discontinuation of one antiplatelet agent as soon as clinically justifiable. Importantly, the impact of prolonged anticoagulation (low-dose rivaroxaban, vitamin-K antagonists) as adjunctive to DAPT after ACS has not been addressed with the most potent antiplatelet agents (prasugrel, ticagrelor) and merits further study. Despite the potential indication of prolonged oral anticoagulation as adjunctive treatment, it remains to be established whether anticoagulation therapy could also be an alternative for either aspirin or thienopyridine treatment in selected ACS patients on DAPT.

Insights into the role of thrombin in the pathogenesis of recurrent ischaemia after acute coronary syndrome

Acute coronary syndrome (ACS) is a medical emergency. Patients who survive the initial event remain at risk of recurrent cardiovascular events. In most cases, ACS is triggered by thrombosis after rupture of an atherosclerotic plaque. Key to thrombus formation at this site is the generation of thrombin, which not only converts fibrinogen to fibrin but also serves as a potent platelet agonist and induces platelet aggregation at the site of vascular injury. Although dual antiplatelet therapy is more effective for the prevention of recurrent events than aspirin alone after ACS, there remains an approximately 10 % risk of recurrent ischaemic events at one year. Recent studies have evaluated whether the addition of an anticoagulant to antiplatelet therapy reduces the risk of recurrent ischaemia after an ACS event. Rivaroxaban, an oral factor Xa inhibitor, attenuates thrombin generation. When used in conjunction with dual antiplatelet therapy in patients with stabilised ACS, rivaroxaban 2.5 mg twice daily significantly reduced the risk of the composite endpoint of cardiovascular death, myocardial infarction and stroke compared with placebo. Although it increased the risk of bleeding, rivaroxaban was associated with a reduction in mortality; a finding that supports the use of a dual-pathway approach that combines anticoagulant and antiplatelet therapy. This review explores the pathophysiology of ACS to provide perspective on the results of recent clinical trials with novel oral anticoagulants for ACS and to identify their potential role in this setting.

Antithrombotic treatment in anticoagulated atrial fibrillation patients undergoing percutaneous coronary intervention

Coronary artery disease coexists in a clinically relevant number of patients with atrial fibrillation and it often requires percutaneous coronary intervention. These patients represent a particular challenge for clinicians in terms of antithrombotic management. They require combined antiplatelet-anticoagulant therapy to reduce the risk of recurrent ischemic cardiac events and stroke; however, this antithrombotic strategy is associated with an increased risk of bleeding complications. In the absence of randomized, controlled clinical trials, the majority of current recommendations rely on the results of cohort studies, meta-analyses, post-hoc analyses and subgroup analyses of large, phase III studies. Based on the available evidence, the present review discusses the optimal antithrombotic strategy for patients receiving chronic anticoagulant therapy due to atrial fibrillation who require antiplatelet treatment after acute coronary syndrome and/or percutaneous coronary intervention, and discusses the issue of dental procedures. The correct planning of therapy significantly reduces the risk of bleeding complications and thromboembolic events.

KEY MESSAGES

In order to reduce the occurrence of recurrent cardiac ischemic events and stroke, anticoagulated patients with acute coronary syndrome and/or percutaneous coronary intervention require a combination of therapies including anticoagulants and antiplatelet drugs. Using the newest optimal combination of therapeutic strategies reduces the risk of haemorrhagic complications.

Strategies to Optimize Dual Antiplatelet Therapy After Coronary Artery Stenting in Acute Coronary Syndrome

The use of aspirin and a P2Y12 receptor antagonist as dual antiplatelet therapy (DAPT) has become the treatment of choice in patients with acute coronary syndrome (ACS) and percutaneous coronary intervention to prevent recurrent thrombotic events. Although DAPT is beneficial for most patients, few patients still experience recurrent thrombotic events and increased bleeding episodes. This article reviews current literature to identify various approaches that may enhance the DAPT benefit-risk ratio in patients with ACS. Three strategies addressed in this article include the following—(1) use of more potent antiplatelet agents other than clopidogrel; (2) addition of direct oral anticoagulants (DOACs) to DAPT; and (3) optimizing DAPT duration. Although the use of prasugrel or ticagrelor improves treatment efficacy, their use has been associated with increased risk of bleeding compared to clopidogrel. The combination of DOACs and DAPT may not be the most viable strategy because of its limited cardiovascular benefits and increased bleeding risks. The optimal duration of DAPT duration remains controversial. Most guidelines recommend 6 to 12 months of DAPT, whereas emerging studies have shown benefit for both shorter and longer duration of treatment. Risk stratification tools such as the DAPT score may play a role in individualizing DAPT duration according to patient’s ischemic and bleeding risks.

Overview of the new oral anticoagulants: opportunities and challenges

The non-vitamin K antagonist oral anticoagulants (NOACs) are replacing warfarin for many indications. These agents include dabigatran, which inhibits thrombin, and rivaroxaban, apixaban, and edoxaban, which inhibit factor Xa. All 4 agents are licensed in the United States for stroke prevention in atrial fibrillation and for treatment of venous thromboembolism and rivaroxaban and apixaban are approved for thromboprophylaxis after elective hip or knee arthroplasty. The NOACs are at least as effective as warfarin, but are not only more convenient to administer because they can be given in fixed doses without routine coagulation monitoring but also are safer because they are associated with less intracranial bleeding. As part of a theme series on the NOACs, this article (1) compares the pharmacological profiles of the NOACs with that of warfarin, (2) identifies the doses of the NOACs for each approved indication, (3) provides an overview of the completed phase III trials with the NOACs, (4) briefly discusses the ongoing studies with the NOACs for new indications, (5) reviews the emerging real-world data with the NOACs, and (6) highlights the potential opportunities for the NOACs and identifies the remaining challenges.

Antithrombotic therapy in patients with acute coronary syndrome in the intermountain heart collaborative study

Objective. To determine factors associated with single antiplatelet (SAP) or dual antiplatelet (DAP) therapy and anticoagulants (AC) use in hospital and after discharge among patients with acute coronary syndrome (ACS). Methods. We evaluated 5,294 ACS patients in the Intermountain Heart Collaborative Study from 2004 to 2009. Multivariable logistic regressions were used to determine predictors of AC or AP use. Results. In hospital, 99% received an AC, 79% DAP, and 19% SAP; 78% had DAP + AC. Coronary stents were the strongest predictors of DAP use in hospital compared to SAP (P < 0.001). After discharge, 77% received DAP, 20% SAP, and 9% AC; 5% had DAP + AC. DAP compared to SAP was less likely for patients on AC (odds ratio [OR] = 0.30, P < 0.0001) after discharge. Placement of a stent increased the likelihood of DAP (bare metal: OR = 54.8, P < 0.0001; drug eluting: OR = 59.4, P < 0.0001). 923 had atrial fibrillation and 337 had a history of venous thromboembolism; these patients had increased use of AC (29% and 40%, resp.). Conclusion. While in-hospital use of AC was nearly universal, postdischarge AC use was rare. Concern for providing the best antithrombotic therapy, while maintaining an acceptable bleeding risk, may explain the selection decisions.

The "dual-pathway" strategy after acute coronary syndrome: rivaroxaban and antiplatelet agents in the ATLAS ACS 2-TIMI 51 trial

Acute coronary syndrome (ACS) is a medical emergency often associated with an occlusive coronary event with consequent myocardial underperfusion. Patients require immediate antiplatelet therapy and long-term antithrombotic prophylaxis to reduce the risk of recurrence. Acetylsalicylic acid (ASA) alone or in combination with a platelet P2Y12 inhibitor (dual antiplatelet therapy [DAPT]) has become the clinically accepted antithrombotic prophylaxis for patients post-ACS. Historically, studies assessing the utility of adding oral anticoagulants (OACs) have not demonstrated a clinical benefit with regard to acceptable bleeding risk. Studies with vitamin K antagonists (VKAs) such as warfarin demonstrated a potential to reduce the risk of subsequent death by reinfarction but this benefit was offset by increases in bleeding. Results from studies of two targeted non-VKA OACs also proved disappointing, with little or no apparent reduction in the rate of ischemic events seen. However, the recent ATLAS studies assessing rivaroxaban (an oral factor Xa inhibitor) in patients with ACS demonstrated a reduction in the composite endpoint of deaths from cardiovascular causes, myocardial infarction (MI), or stroke, and a reduction in the rate of stent thrombosis. This review provides an overview of the pivotal studies in which the addition of OACs to antiplatelet therapy (the so-called "dual-pathway" approach) has been investigated for the management of patients post-ACS and considers the results of the ATLAS studies and their potential impact on the management of patients after an acute event.

Rivaroxaban in patients with a recent acute coronary syndrome event: integration of trial findings into clinical practice

Despite significant advances in the management of acute coronary syndrome (ACS) and long-term antiplatelet therapy after an ACS event, patients continue to be at risk of further cardiovascular events. There is evidence that recurrent events are at least partly attributed to the persistent activation of the coagulation system after ACS. Various anticoagulants, including vitamin K antagonists (VKAs) and non-VKA oral anticoagulants, have been evaluated in patients post-ACS, in combination with antiplatelet therapy. The desired outcome would be a further reduction of recurrent cardiovascular events with low or acceptable levels of bleeding complications. Here, we provide an overview of the current clinical trial data of non-VKA oral anticoagulants, focusing on rivaroxaban in particular, for secondary prevention in patients with a recent ACS event.

Anticoagulants for secondary prevention after acute myocardial infarction: lessons from the past decade

The impact of an acute coronary syndrome (ACS) event, such as an acute myocardial infarction (MI), is not limited to the acute management phase; patients face an elevated risk of residual atherothrombotic events that commonly requires chronic management for months or even years. Significant advances have been made in both the acute and chronic management of patients with acute MI over the past decade, resulting in improved prognoses. One of the hallmarks of modern treatment strategies is more aggressive antiplatelet treatment regimens. However, the risks of further ACS events, stroke and premature death remain elevated in these patients, and addressing this residual risk is challenging owing to interpatient variability, differences in management strategies between centres and countries, incomplete understanding of the specific pathophysiology of post-ACS thrombosis and limitations of current therapeutic approaches. The recent approval in Europe of the direct oral anticoagulant rivaroxaban for use in this setting in combination with clopidogrel and acetylsalicylic acid offers another strategy to consider in the management of these patients, and clinical strategies in this area continue to evolve. In this review, we chart the progress made over the past decade in reducing the burden of secondary thromboembolic events after acute MI and discuss the current position of and future perspectives on the inclusion of oral anticoagulants into care pathways in this setting.

Adjusted indirect comparison of new oral anticoagulants for stroke prevention in atrial fibrillation

BACKGROUND

Vit-K antagonists are the therapy of choice to prevent thromboembolic events due to atrial fibrillation since many years. New oral anticoagulants (NOA) showed encouraging results vs. warfarin but there are no data directly comparing different NOA. We performed an adjusted indirect meta-analysis.

METHODS

Randomized controlled trials (RCTs) were searched. Efficacy end points were the cumulative rate of thomboembolic stroke (TES) and systemic embolism (SE). Main safety end point was the rate of hemorrhagic stroke (HS).

RESULTS

Three RCTs (50578 patients) were included. Overall, NOA were comparable to warfarin according to the cumulative risk of TES and SE, as well as for TES alone. NOA were associated with a reduced rate of SE [OR 0.64 (0.44, 0.94], P=0.02]. Compared to warfarin, NOA were associated with a significantly reduced risk of HS [OR 0.43 (0.34, 0.55), P<0.001, NNT to avoid a HS 153] and all cause death [OR 0.90 [0.84, 0.96], P=0.03, NNT to save one fatality 43]. Head to head comparison showed that in terms of cumulative rate of TES/SE, as well as of TES, none of the NOA was significantly superior to the others (all Ps>0.05). Rivaroxaban showed superiority in the prevention of SE. Dabigatran 150 mg/twice daily was associated with the largest reduction in the risk of HS vs. warfarin and vs. other NOA. Overall mortality was quite comparable across NOA.

CONCLUSION

Overall superiority of NOA over warfarin is largely influenced by the reduction of HS. Dabigatran 150 mg/twice daily seems to have the best risk/benefit profile.

Targeted therapy for patients with chronic myeloid leukemia: clinical trial experience and challenges in inter-trial comparisons

The treatment of chronic myeloid leukemia (CML) was revolutionized by the introduction of the targeted tyrosine kinase inhibitor (TKI) imatinib mesylate. Later, to improve efficacy and tolerability, the more potent TKIs dasatinib and nilotinib were evaluated in CML. Clinicians comparing the clinical efficacy of TKIs face considerable challenges, including the variable treatment histories of patients receiving second-line therapy. The aim of this review is to highlight the pitfalls and possible solutions for comparing efficacy across disparate CML trials. Comparison of efficacy across trials is aided by careful consideration of possible confounding factors, including treatment history, definitions of imatinib intolerance or resistance, and BCR-ABL mutational status at baseline. However, methods exist to improve the comparability of data from different trials, yielding a more clinically and statistically meaningful inter-trial comparison.

Adjusted indirect comparison meta-analysis of prasugrel versus ticagrelor for patients with acute coronary syndromes

BACKGROUND

Clopidogrel is beneficial after ACS. Recent data suggest the superiority of prasugrel or ticagrelor compared with clopidogrel. However, there is no comparison of prasugrel vs. ticagrelor. We performed an adjusted indirect meta-analysis comparing prasugrel vs. ticagrelor for acute coronary syndromes (ACSs).

METHODS

Randomized trials were searched in PubMed. The primary end-point was the composite of death, myocardial infarction (MI) or stroke. Odds ratios (OR) were computed (95% confidence intervals).

RESULTS

Three trial (32,893) patients were included. Overall, either prasugrel or ticagrelor appeared significantly superior to clopidogrel for the 12-month risk of death, MI or stroke (OR=0.83 [0.77-0.89], p<0.001), death (OR=0.83 [0.74-0.93], p=0.001), MI (OR=0.79 [0.73-0.86], p<0.001), and stent thrombosis (OR=0.61 [0.51-0.74], p<0.001), without any significant difference in stroke or major bleeding (both p>0.05), despite more frequent drug discontinuation (OR=1.12 [1.05-1.19], p<0.001). Head-to-head comparison of prasugrel vs. ticagrelor showed no significant differences in overall death, MI, stroke, or their composite (all p>0.05). Prasugrel was associated with a significantly lower risk of stent thrombosis (OR=0.64 [0.43-0.93], p=0.020). Ticagrelor was associated with a significantly lower risk of any major bleeding (OR=1.43 [1.10-1.85], p=0.007), and major bleeding associated with bypass grafting (OR=4.30 [1.73-10.6], p=0.002). However, the more clinically relevant risk of major bleeding not related to bypass surgery was similar with either prasugrel or ticagrelor (OR=1.06 [0.77-1.45], p=0.34).

CONCLUSIONS

Prasugrel and ticagrelor are superior to clopidogrel for ACS. Head-to-head comparison suggests similar efficacy and safety of prasugrel and ticagrelor, but prasugrel appears more protective from stent thrombosis, while causing more bleedings.

Impact of anticoagulant therapy with dual antiplatelet therapy on prognosis after treatment with drug-eluting coronary stents

BACKGROUND

Although combination therapy for various cardiac conditions with dual antiplatelet therapy (aspirin and thienopyridine derivatives) and warfarin sodium has become increasingly popular, the safety and effectiveness of this aggressive treatment regimen remain unknown.

METHODS AND RESULTS

We retrospectively enrolled and analyzed 575 consecutive patients who had been implanted with drug-eluting coronary stents. The primary and secondary endpoints were major bleeding complications and major adverse cardiovascular events (MACE), respectively. At the time of discharge, 525 patients (91.3%) were prescribed with dual antiplatelet therapy, and 50 (8.7%) of them received dual antiplatelet plus anticoagulant therapy (triple therapy). The patients treated with triple therapy had a greater prevalence of comorbid conditions, including left ventricular systolic dysfunction and multi-vessel coronary disease compared to those on the dual antiplatelet regimen. During a median follow-up of 459 days, 14 (2.7%) patients receiving dual, and 9 (18.0%) receiving triple therapy reached the primary endpoint (p<0.001). These results show that warfarin use was associated with an increased risk of subsequent major bleeding. On the other hand, the incidence of MACE did not differ between the two groups (p=0.108 by the log-rank test). Multivariate analysis showed that renal impairment was an independent predictor of the risk of subsequent major bleeding in the triple therapy group.

CONCLUSIONS

Triple therapy increased the hemorrhagic complications in patients after percutaneous coronary intervention with drug-eluting stents, especially in patients with impaired renal function. Great caution should be taken with patients who necessitate the addition of anticoagulation therapy with warfarin to dual antiplatelet therapy.

Combining antiplatelet and anticoagulant therapies

Antiplatelet therapy is the cornerstone for both primary and secondary prevention therapies for ischemic events resulting from coronary atherosclerotic disease. Dual antiplatelet therapy (aspirin plus a thienopyridine, usually clopidogrel) has assumed a central role in the treatment of acute coronary syndromes and after coronary stent deployment. In addition to antiplatelet therapy, anticoagulant therapy might be indicated for stroke prevention in a variety of conditions that include atrial fibrillation, profound left ventricular dysfunction, and after mechanical prosthetic heart valve replacement. For this reason, the use of triple antithrombotic therapy (a dual antiplatelet regimen plus warfarin) is expected to become more prominent, given an aging patient population. But although triple therapy can prevent both thromboembolism and stent thrombosis, it is also associated with significant bleeding hazards. Furthermore, when bleeding events do occur, the challenge of balancing the risk of stent thrombosis or stroke and the need for hemostasis requires considerable expertise. It is both prudent and timely to review treatment strategies that employ combinations of antiplatelet and anticoagulant therapies as well as strategies aimed at reducing bleeding risk in patients treated with these therapies.

Apixaban, an Oral, Direct, Selective Factor Xa Inhibitor, in Combination With Antiplatelet Therapy After Acute Coronary Syndrome

Background— After an acute coronary syndrome, patients remain at risk of recurrent events. Apixaban, an oral direct factor Xa inhibitor, is a novel anticoagulant that may reduce these events but also poses a risk of bleeding.

Methods and Results— Apixaban for Prevention of Acute Ischemic and Safety Events (APPRAISE) was a phase 2, double-blind, placebo-controlled, dose-ranging study. Patients (n=1715) with recent ST-elevation or non-ST-elevation acute coronary syndrome were randomized to 6 months of placebo (n=611) or 1 of 4 doses of apixaban: 2.5 mg twice daily (n=317), 10 mg once daily (n=318), 10 mg twice daily (n=248), or 20 mg once daily (n=221). Nearly all patients received aspirin; 76% received clopidogrel. The primary outcome was International Society of Thrombosis and Hemostasis major or clinically relevant nonmajor bleeding. A secondary outcome was cardiovascular death, myocardial infarction, severe recurrent ischemia, or ischemic stroke. At the recommendation of the Data Monitoring Committee, the 2 higher-dose apixaban arms were discontinued because of excess total bleeding. Compared with placebo, apixaban 2.5 mg twice daily (hazard ratio, 1.78; 95% confidence interval, 0.91 to 3.48; P =0.09) and 10 mg once daily (hazard ratio, 2.45; 95% confidence interval, 1.31 to 4.61; P =0.005) resulted in a dose-dependent increase in major or clinically relevant nonmajor bleeding. Apixaban 2.5 mg twice daily (hazard ratio, 0.73; 95% confidence interval, 0.44 to 1.19; P =0.21) and 10 mg once daily (hazard ratio, 0.61; 95% confidence interval, 0.35 to 1.04; P =0.07) resulted in lower rates of ischemic events compared with placebo. The increase in bleeding was more pronounced and the reduction in ischemic events was less evident in patients taking aspirin plus clopidogrel than in those taking aspirin alone.

Conclusions— We observed a dose-related increase in bleeding and a trend toward a reduction in ischemic events with the addition of apixaban to antiplatelet therapy in patients with recent acute coronary syndrome. The safety and efficacy of apixaban may vary depending on background antiplatelet therapy. Further testing of apixaban in patients at risk of recurrent ischemic events is warranted.

Antithrombotic therapy and outcomes of patients with atrial fibrillation following primary percutaneous coronary intervention: results from the APEX-AMI trial

AIMS

To assess the incidence and timing of atrial fibrillation (AF), describe antithrombotic therapy use, and evaluate the association of AF with 90 day mortality and other secondary clinical outcomes.

METHODS AND RESULTS

We studied 5745 ST-segment elevation myocardial infarction patients treated with primary percutaneous coronary intervention (PCI) in APEX-AMI. Approximately 11% had AF during hospitalization. Atrial fibrillation prevalence at baseline and at discharge was 4.8% [confidence interval (CI) 4.3-5.4%] and 2.5% (CI 2.1-2.9%), respectively. The proportion of 5466 patients without AF at baseline who developed new onset AF was 6.3% (CI 5.6-6.9%). This corresponded to 9.3 cases of new onset AF/1000 patient days at risk. New onset AF was independently associated with 90 day mortality [adjusted hazard ratio (HR) 1.81; 95% CI 1.06-3.09; P = 0.029] after accounting for baseline covariates and in-hospital procedures and complications. New onset AF was associated with shock (adjusted HR 3.81; 95% CI 1.88-7.70; P = 0.0002), congestive heart failure (adjusted HR 2.66; 95% CI 1.74-4.06; P < 0.0001), and stroke (adjusted HR 2.98; 95% CI 1.47-6.04; P = 0.0024) in models accounting for baseline covariates. Of AF patients, 55% did not receive oral anticoagulation therapy at discharge. Among patients with coronary stents, 5.1% were discharged on triple therapy. Patients at highest risk of stroke (CHADS(2) score > or =2) were least likely to receive oral anticoagulation at discharge (39%). Warfarin use in patients with AF at discharge (43.4%) was associated with lower rates of 90 day mortality and stroke.

CONCLUSION

Atrial fibrillation prevalence at baseline and at discharge was 4.8 and 2.5%, respectively. The proportion of patients who developed new onset AF was 6.3%. New onset AF was independently associated with 90 day mortality and was a marker of adverse outcomes in patients undergoing primary PCI.

Long-term effect of chronic oral anticoagulation: focus on coronary artery disease

Coronary artery disease remains one of the most important causes of morbidity and mortality worldwide, with a disease burden that does not seem to have decreased significantly over time. Since their developments, oral drugs that are able to reduce the coagulation properties of blood (i.e., oral anticoagulants such as warfarin or dicoumarol) have been tested in thousands of patients with, or suspected with, coronary artery disease, however they have yielded disparate and conflicting results. The advent of oral antiplatelet agents has further put into a niche the apparent role of oral anticoagulant therapy in subjects with established coronary artery disease (i.e., in the setting of secondary prevention). However, the current and future role of oral anticoagulants in the secondary prevention of coronary artery disease remains very important, as testified to by the ongoing research by several major companies and investigators focusing on the development of novel oral anticoagulants. This review provides a succinct and updated appraisal of the long-term effects of chronic oral anticoagulation in the setting of coronary artery disease.

Systematic reviews as a tool for planning and interpreting trials

BACKGROUND

Systematic reviews followed by a meta-analysis are carried out in medical research to combine the results of two or more related studies. Stroke trials have struggled to show beneficial effects and meta-analysis should be used more widely throughout the research process to either speed up the development of useful interventions, or halt more quickly research with hazardous or ineffective interventions.

SUMMARY OF REVIEW

This review summarises the clinical research process and illustrates how and when systematic reviews may be used throughout the development programme. Meta-analyses should be performed after observational studies, preclinical studies in experimental stroke, and after phase I, II, and III clinical trials and phase IV clinical surveillance studies. Although meta-analyses most commonly work with summary data, they may be performed to assess relationships between variables (meta-regression) and, ideally, should utilise individual patient data. Meta-analysis techniques may also work with ordered categorical outcome data (ordinal meta-analysis) and be used to perform indirect comparisons where original trial data do not exist.

CONCLUSION

Systematic review/meta-analyses are powerful tools in medical research and should be used throughout the development of all stroke and other interventions.

Prolonged anticoagulation therapy adjunctive to aspirin after successful fibrinolysis: from early reduction in reocclusion to improved long-term clinical outcome

BACKGROUND

Long-term addition of antithrombotics (clopidogrel, anticoagulants) to aspirin has improved outcome after acute coronary syndromes. Data on the impact after fibrinolysis are scarce. In Antithrombotics in the Prevention of Reocclusion In COronary Thrombolysis-2 (APRICOT-2), adjunctive moderate-intensity coumarin (median international normalized ratio 2.6) conferred a marked reduction in 3-month reocclusion and ischemic events. Given the association between reocclusion and long-term outcome, we performed long-term clinical follow-up.

METHODS

Patients with thrombolysis in myocardial infarction (TIMI) 3 flow <48 hours after fibrinolysis for ST-elevation myocardial infarction were randomized to aspirin plus coumarin, with prolonged heparinization until the target international normalized ratio (2-3) was reached, or aspirin with standard heparinization. Three-month follow-up angiography (reocclusion rates 15% vs 28%) and long-term clinical follow-up (median 7.3 years, interquartile range 5.9-8.6 years) were performed.

RESULTS

Patients randomized to adjunctive anticoagulation (n = 123) received coumarin for a median of 280 days (113-387 days). Survival was 94% versus 88% in patients on aspirin alone (n = 128, P = .12). Infarct-free survival was 86% versus 71% (P = .01). Thrombolysis in myocardial infarction bleeding was 4% in both groups. Patients with reocclusion had impaired survival: 80% versus 94% (P < .01). In a multivariable model without reocclusion, combination therapy independently predicted survival (hazard ratio [HR] 0.36, 95% confidence interval [CI] 0.13-1.00) and infarct-free survival (HR 0.51, 95% CI 0.28-0.95). When adjusted for reocclusion, combination therapy did not predict outcome. Reocclusion independently predicted death (HR 2.56, 95% CI 1.02-6.43) and reinfarction.

CONCLUSIONS

Moderate-intensity oral anticoagulation added to aspirin improved 8-year clinical outcome after successful fibrinolysis. The beneficial effect was largely attributed to a reduction in reocclusion, which independently predicted death and reinfarction. This study provides a mechanistic rationale for prolonged adjunctive anticoagulation after fibrinolysis.

Use of antiplatelet agents for prevention of ischemic stroke

Overall management to lower risk for ischemic stroke is multifaceted. Management includes measures to treat risk factors for accelerated atherosclerosis and stroke, antithrombotic therapies to lower the risk for thromboembolism, and surgery to treat a defined arterial or cardiac lesion. Treatment decisions are made on a case-by-case basis, with most patients receiving some combination of medication and recommendations for lifestyle modification. Some patients will also undergo surgical or endovascular interventions. This article discusses antithrombotic treatment for ischemic stroke prevention, placing major emphasis on the indications for and administration of antiplatelet therapy.

Prevalence, clinical profile, and cardiovascular outcomes of atrial fibrillation patients with atherothrombosis

BACKGROUND

Atrial fibrillation (AF) is a major risk factor (RF) for ischemic stroke. Its prevalence and prognostic impact in patients with atherothrombosis are unclear.

METHODS

Risk factors, drug usage, and 1-year cardiovascular (CV) outcomes (CV death, myocardial infarction [MI], and stroke) were compared in AF and non-AF patients from the REduction of Atherothrombosis for Continued Health (REACH) Registry, an international, prospective cohort of 68,236 stable outpatients with established atherothrombosis or>or=3 atherothrombotic RFs.

RESULTS

Atrial fibrillation and 1-year follow-up data are available for 63,589 patients. The prevalence of AF was, 12.5%, 13.7%, 11.5%, and 6.2% among coronary artery disease, CV disease, peripheral artery disease, and RF-only patients, respectively. Of the 6,814 patients with AF, 6.7% experienced CV death, nonfatal MI, or nonfatal stroke within a year. The annual incidence of nonfatal stroke (2.4% vs 1.6%, P<.0001) and unstable angina (6.0% vs 4.0%, P<.00001) was higher, and CV death was more than double (3.2% vs 1.4%, P<.0001), in AF versus non-AF patients. In these patients with or at high risk of atherothrombosis, most patients with AF received antiplatelet agents, but only 53.1% were treated with oral anticoagulants. Even with high CHADS2 (congestive heart failure, hypertension, aging, diabetes mellitus, and stroke) scores, anticoagulant use did not exceed (59%). The rate of bleeding requiring hospitalization was higher in AF versus non-AF patients (1.5% vs 0.8%, P<.0001), possibly related to the more frequent use of anticoagulants (53.1% vs 7.1%).

CONCLUSIONS

Atrial fibrillation is common in patients with atherothrombosis, associated with more frequent fatal and nonfatal CV outcomes, and underuse of oral anticoagulants.

Systematic review: nutritional support in acute pancreatitis

BACKGROUND

There has been controversy concerning the merits of enteral and parenteral nutrition compared with no supplementary nutrition in the management of patients with acute pancreatitis.

AIM

To perform a systematic review of the data from randomized controlled trials (RCTs) in acute pancreatitis that compares enteral nutrition with no supplementary nutrition, parenteral nutrition with no supplementary nutrition and enteral nutrition with parenteral nutrition.

METHODS

A search was undertaken in the MEDLINIE, EMBASE and the Cochrane Central Register of Controlled Trials.

RESULTS

Fifteen RCTs were included. Enteral nutrition, when compared with no supplementary nutrition, was associated with no significant change in infectious complications: ratio of relative risks (RR) 0.56, 95% confidence interval (CI) 0.07-4.32, P = 0.58, but a significant reduction in mortality: ratio of RR 0.22, 95% CI 0.07-0.70, P = 0.01. Parenteral nutrition, when compared with no supplementary nutrition, was associated with no significant change in infectious complications: RR 1.36, 95% CI 0.18-10.40; P = 0.77, but a significant reduction in mortality: RR 0.36, 95% CI 0.13-0.97, P = 0.04. Enteral nutrition, when compared with parenteral nutrition, was associated with a significant reduction in infectious complications: RR 0.41, 95% CI 0.30-0.57, P < 0.001, but no significant change in mortality: RR 0.60, 95% CI 0.32-1.14, P = 0.12.

CONCLUSIONS

The use of either enteral or parenteral nutrition, in comparison with no supplementary nutrition, is associated with a lower risk of death in acute pancreatitis. Enteral nutrition is associated with a lower risk of infectious complications compared with parenteral nutrition.