Factor Xa inhibitors versus vitamin K antagonists for preventing cerebral or systemic embolism in patients with atrial fibrillation.

BACKGROUND: Factor Xa inhibitors and vitamin K antagonists (VKAs) are now recommended in treatment guidelines for preventing stroke and systemic embolic events in people with atrial fibrillation (AF). This is an update of a Cochrane review previously published in 2013. OBJECTIVES: To assess the effectiveness and safety of treatment with factor Xa inhibitors versus VKAs for preventing cerebral or systemic embolic events in people with AF. SEARCH METHODS: We searched the trials registers of the Cochrane Stroke Group and the Cochrane Heart Group (September 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) (August 2017), MEDLINE (1950 to April 2017), and Embase (1980 to April 2017). We also contacted pharmaceutical companies, authors and sponsors of relevant published trials. We used outcome data from marketing authorisation applications of apixaban, edoxaban and rivaroxaban that were submitted to regulatory authorities in Europe and the USA. SELECTION CRITERIA: We included randomised controlled trials (RCTs) that directly compared the effects of long-term treatment (lasting more than four weeks) with factor Xa inhibitors versus VKAs for preventing cerebral and systemic embolism in people with AF. DATA COLLECTION AND ANALYSIS: The primary efficacy outcome was the composite endpoint of all strokes and systemic embolic events. Two review authors independently extracted data, and assessed the quality of the trials and the risk of bias. We calculated a weighted estimate of the typical treatment effect across trials using the odds ratio (OR) with 95% confidence interval (CI) by means of a fixed-effect model. In case of moderate or high heterogeneity of treatment effects, we used a random-effects model to compare the overall treatment effects. We also performed a pre-specified sensitivity analysis excluding any open-label studies. MAIN RESULTS: We included data from 67,688 participants randomised into 13 RCTs. The included trials directly compared dose-adjusted warfarin with either apixaban, betrixaban, darexaban, edoxaban, idraparinux, idrabiotaparinux, or rivaroxaban. The majority of the included data (approximately 90%) was from apixaban, edoxaban, and rivaroxaban.The composite primary efficacy endpoint of all strokes (both ischaemic and haemorrhagic) and non-central nervous systemic embolic events was reported in all of the included studies. Treatment with a factor Xa inhibitor significantly decreased the number of strokes and systemic embolic events compared with dose-adjusted warfarin in participants with AF (OR 0.89, 95% CI 0.82 to 0.97; 13 studies; 67,477 participants; high-quality evidence).Treatment with a factor Xa inhibitor significantly reduced the number of major bleedings compared with warfarin (OR 0.78, 95% CI 0.73 to 0.84; 13 studies; 67,396 participants; moderate-quality evidence). There was, however, statistically significant and high heterogeneity (I2 = 83%). When we repeated this analysis using a random-effects model, it did not show a statistically significant decrease in the number of major bleedings (OR 0.88, 95% CI 0.66 to 1.17). A pre-specified sensitivity analysis excluding all open-label studies showed that treatment with a factor Xa inhibitor significantly reduced the number of major bleedings compared with warfarin (OR 0.75, 95% CI 0.69 to 0.81), but high heterogeneity was also observed in this analysis (I2 = 72%). The same sensitivity analysis using a random-effects model also showed a statistically significant decrease in the number of major bleedings in participants treated with factor Xa inhibitors (OR 0.76, 95% CI 0.60 to 0.96).Treatment with a factor Xa inhibitor significantly reduced the risk of intracranial haemorrhages (ICHs) compared with warfarin (OR 0.50, 95% CI 0.42 to 0.59; 12 studies; 66,259 participants; high-quality evidence). We observed moderate, but statistically significant heterogeneity (I2 = 55%). The pre-specified sensitivity analysis excluding open-label studies showed that treatment with a factor Xa inhibitor significantly reduced the number of ICHs compared with warfarin (OR 0.47, 95% CI 0.40 to 0.56), with low, non-statistically significant heterogeneity (I2 = 27%).Treatment with a factor Xa inhibitor also significantly reduced the number of all-cause deaths compared with warfarin (OR 0.89, 95% 0.83 to 0.95; 10 studies; 65,624 participants; moderate-quality evidence). AUTHORS' CONCLUSIONS: Treatment with factor Xa inhibitors significantly reduced the number of strokes and systemic embolic events compared with warfarin in people with AF. The absolute effect of factor Xa inhibitors compared with warfarin treatment was, however, rather small. Factor Xa inhibitors also reduced the number of ICHs, all-cause deaths and major bleedings compared with warfarin, although the evidence for a reduction in the latter is less robust.

Percutaneous vascular interventions versus intravenous thrombolytic treatment for acute ischaemic stroke.

BACKGROUND: Most ischaemic strokes are caused by blockage of a cerebral artery by a thrombus. Intravenous administration of recombinant tissue plasminogen activator given within 4.5 hours is now standard treatment for this condition. Percutaneous vascular interventions use an intra-arterial, mechanical approach for thrombus disruption or removal (thrombectomy). Recent randomised trials indicate that percutaneous vascular interventions are superior to usual care (usual care usually included intravenous thrombolysis). However, intravenous thrombolysis was usually given in both arms of the trial and there was a lack of direct comparison of percutaneous vascular interventions with intravenous thrombolysis. OBJECTIVES: To assess the effectiveness and safety of percutaneous vascular interventions compared with intravenous thrombolytic treatment for acute ischaemic stroke. SEARCH METHODS: We searched the Cochrane Stroke Group Trials Register (last search: August 2018). In addition, in September 2017, we searched the following electronic databases: CENTRAL, MEDLINE, Embase, and Science Citation Index; and Stroke Trials Registry, and US National Institutes of Health Ongoing Trials Register, ClinicalTrials.gov. SELECTION CRITERIA: Randomised controlled trials (RCTs) that directly compared a percutaneous vascular intervention with intravenous thrombolytic treatment in people with acute ischaemic stroke. DATA COLLECTION AND ANALYSIS: Two review authors applied the inclusion criteria, extracted data, and assessed risk of bias. We obtained both published and unpublished data. We assessed the quality of the evidence using the GRADE approach. MAIN RESULTS: We included four trials with 450 participants. Data on functional outcome and death at end of follow-up were available for 443 participants from three trials. Compared with intravenous thrombolytic therapy, percutaneous vascular intervention did not improve the proportion of participants with good functional outcome (modified Rankin Scale score 0 to 2, risk ratio (RR) 1.01, 95% confidence interval (CI) 0.82 to 1.25, P = 0.92). The quality of evidence was low (outcome assessment was blinded, but not the treating physician or participants). At the end of follow-up, there was a non-significant increase in the proportion of participants who died in the percutaneous vascular intervention group (RR 1.34, 95% CI 0.84 to 2.14, P = 0.21). The quality of evidence was low (wide confidence interval). There was no difference in the proportion of participants with symptomatic intracranial haemorrhages between the intervention and control groups (RR 0.99, 95% CI 0.50 to 1.95, P = 0.97). The quality of evidence was low (wide confidence interval). Data on vascular status (recanalisation rate) were only available for seven participants from one trial; we considered this inadequate for statistical analyses. AUTHORS' CONCLUSIONS: The present review directly compared intravenous thrombolytic treatment with percutaneous vascular interventions for ischaemic stroke. We found no evidence from RCTs that percutaneous vascular interventions are superior to intravenous thrombolytic treatment with respect to functional outcome. Quality of evidence was low (outcome assessment was blinded, but not the treating physician or participants). New trials with adequate sample sizes are warranted because of the rapid development of new techniques and devices for such interventions.