Efficacy and safety of short-term dual- versus mono-antiplatelet therapy in patients with ischemic stroke or TIA: a meta-analysis of 10 randomized controlled trials

P2Y12 Inhibitors Plus Aspirin Versus Aspirin Alone in Patients With Minor Stroke or High-Risk Transient Ischemic Attack

BACKGROUND AND PURPOSE

We performed a systemic review and meta-analysis to elucidate the effectiveness and safety of dual antiplatelet (DAPT) therapy with P2Y12 inhibitors (clopidogrel/ticagrelor) and aspirin versus aspirin monotherapy in patients with mild ischemic stroke or high-risk transient ischemic attack.

METHODS

Following Preferred Reported Items for Systematic Review and Meta-Analysis standards for meta-analyses, Medline, Embase, Cochrane Central Register of Controlled Trials, and the Cochrane Library were searched for randomized controlled trials that included patients with a diagnosis of an acute mild ischemic stroke or high-risk transient ischemic attack, intervention of DAPT therapy with clopidogrel/ticagrelor and aspirin versus aspirin alone from January 2012 to July 2020. The outcomes included subsequent stroke, all-cause mortality, cardiovascular death, hemorrhage (mild, moderate, or severe), and myocardial infarction. A DerSimonian-Laird random-effects model was used to estimate pooled risk ratio (RR) and corresponding 95% CI in R package meta. We assessed the heterogeneity of data across studies with use of the Cochran Q statistic and I² test.

RESULTS

Four eligible trials involving 21 493 participants were included in the meta-analysis. DAPT therapy started within 24 hours of symptom onset reduced the risk of stroke recurrence by 24% (RR, 0.76 [95% CI, 0.68-0.83], I²=0%) but was not associated with a change in all-cause mortality (RR, 1.30 [95% CI, 0.90-1.89], I²=0%), cardiovascular death (RR, 1.34 [95% CI, 0.56-3.17], I²=0%), mild bleeding (RR, 1.25 [95% CI, 0.37-4.29], I²=94%), or myocardial infarction (RR, 1.45 [95% CI, 0.62-3.39], I²=0%). However, DAPT was associated with an increased risk of severe or moderate bleeding (RR, 2.17 [95% CI, 1.16-4.08], I²=41%); further sensitivity tests found that the association was limited to trials with DAPT treatment duration over 21 days (RR, 2.86 [95% CI, 1.75-4.67], I²=0%) or ticagrelor (RR, 2.17 [95% CI, 1.16-4.08], I²=37%) but not within 21 days or clopidogrel.

CONCLUSIONS

In patients with noncardioembolic mild stroke or high-risk transient ischemic attack, DAPT with aspirin and clopidogrel/ticagrelor is more effective than aspirin alone for recurrent stroke prevention with a small absolute increase in the risk of severe or moderate bleeding.

Clopidogrel plus aspirin versus aspirin alone for acute minor ischaemic stroke or high risk transient ischaemic attack: systematic review and meta-analysis

OBJECTIVE

To assess the effectiveness and safety of dual agent antiplatelet therapy combining clopidogrel and aspirin to prevent recurrent thrombotic and bleeding events compared with aspirin alone in patients with acute minor ischaemic stroke or transient ischaemic attack (TIA).

DESIGN

Systematic review and meta-analysis of randomised, placebo controlled trials.

DATA SOURCES

Medline, Embase, Cochrane Central Register of Controlled Trials, Cochrane Library, ClinicalTrials.gov, WHO website, PsycINFO, and grey literature up to 4 July 2018.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES AND METHODS

Two reviewers independently screened potentially eligible studies according to predefined selection criteria and assessed the risk of bias using a modified version of the Cochrane risk of bias tool. A third team member reviewed all final decisions, and the team resolved disagreements through discussion. When reports omitted data that were considered important, clarification and additional information was sought from the authors. The analysis was conducted in RevMan 5.3 and MAGICapp based on GRADE methodology.

RESULTS

Three eligible trials involving 10 447 participants were identified. Compared with aspirin alone, dual antiplatelet therapy with clopidogrel and aspirin that was started within 24 hours of symptom onset reduced the risk of non-fatal recurrent stroke (relative risk 0.70, 95% confidence interval 0.61 to 0.80, I²=0%, absolute risk reduction 1.9%, high quality evidence), without apparent impact on all cause mortality (1.27, 0.73 to 2.23, I²=0%, moderate quality evidence) but with a likely increase in moderate or severe extracranial bleeding (1.71, 0.92 to 3.20, I²=32%, absolute risk increase 0.2%, moderate quality evidence). Most stroke events, and the separation in incidence curves between dual and single therapy arms, occurred within 10 days of randomisation; any benefit after 21 days is extremely unlikely.

CONCLUSIONS

Dual antiplatelet therapy with clopidogrel and aspirin given within 24 hours after high risk TIA or minor ischaemic stroke reduces subsequent stroke by about 20 in 1000 population, with a possible increase in moderate to severe bleeding of 2 per 1000 population. Discontinuation of dual antiplatelet therapy within 21 days, and possibly as early as 10 days, of initiation is likely to maximise benefit and minimise harms.

Effect of Antiplatelet Therapy (Aspirin + Dipyridamole Versus Clopidogrel) on Mortality Outcome in Ischemic Stroke

The optimal regimen of antiplatelet therapy for secondary prevention in noncardioembolic ischemic stroke remains controversial. We aimed to determine which regimen was associated with the greatest reduction in adverse outcomes. We analysed prospectively collected data from the Norfolk and Norwich University Hospital Stroke Register. The sample population consisted of 3,572 participants (mean age 74.96 ± 12.67) with ischemic stroke, who were consecutively admitted between 2003 and 2015. Patients were placed on one of three antiplatelet regimens at hospital discharge; aspirin monotherapy, aspirin plus dipyridamole and clopidogrel. Clopidogrel and aspirin plus dipyridamole were compared to aspirin. A direct comparison between clopidogrel and aspirin plus dipyridamole was also performed. Outcomes included all-cause mortality and a combined end point of all-cause mortality and incidence of major adverse cardiac events (stroke or myocardial infarction). Cox-regression models adjusted for potential confounders at the following time periods after discharge; 0 to 90 days, 91 to 365 days, and 1 to 3 years. Aspirin plus dipyridamole was associated with a lower risk of mortality at 0 to 90 days; hazard ratio (HR) 0.62 (0.43 to 0.91). Clopidogrel was associated with a lower risk of mortality at 1 to 3 years; HR of 0.39 (0.26 to 0.60). Similar HRs were observed for the corresponding time points in the composite outcome. In conclusion, patients with noncardioembolic stroke may gain maximum benefits from aspirin plus dipyridamole initially (≤1 year) with a subsequent switch to clopidogrel, with regard to mortality and major adverse cardiac eventsoutcomes.

Recent advances in the management of transient ischemic attacks

Significant advances in our understanding of transient ischemic attack (TIA) have taken place since it was first recognized as a major risk factor for stroke during the late 1950's. Recently, numerous studies have consistently shown that patients who have experienced a TIA constitute a heterogeneous population, with multiple causative factors as well as an average 5–10% risk of suffering a stroke during the 30 days that follow the index event. These two attributes have driven the most important changes in the management of TIA patients over the last decade, with particular attention paid to effective stroke risk stratification, efficient and comprehensive diagnostic assessment, and a sound therapeutic approach, destined to reduce the risk of subsequent ischemic stroke. This review is an outline of these changes, including a discussion of their advantages and disadvantages, and references to how new trends are likely to influence the future care of these patients.