Dabigatran versus vitamin k antagonist: an observational across-cohort comparison in acute coronary syndrome patients with atrial fibrillation

Direct Oral Anticoagulants vs. Warfarin in Latin American Patients With Atrial Fibrillation: Evidence From Four post-hoc Analyses of Randomized Clinical Trials

Background

Several studies have investigated the effect of direct oral anticoagulants (DOACs) in Latin American patients with atrial fibrillation (AF), but the results remain controversial. Therefore, we aimed to compare the efficacy and safety of DOACs vs. warfarin in Latin American patients with AF.

Methods

We systematically searched the PubMed and Embase databases until November 2021 for studies that compared the effect of DOACs vs. warfarin in Latin patients with AF. Adjusted hazard ratios (HRs) and 95% CIs were pooled by a random-effects model using an inverse variance method.

Results

Four post-hoc analyses of randomized clinical trials (RCTs) involving 42,411 DOACs and 29,270 warfarin users were included. In Latin American patients with AF, for the effectiveness outcomes, the use of DOACs compared with warfarin was significantly associated with decreased risks of stroke or systemic embolism (SSE) (HR = 0.78; 95%CI.64–0.96), stroke (HR = 0.75; 95%CI.57–0.99), hemorrhagic stroke (HR = 0.14; 95%CI.05–0.36), all-cause death (HR = 0.89; 95% CI.80–1.00), but not ischemic stroke and cardiovascular death. For the safety outcomes, compared with warfarin, the use of DOACs was associated with reduced risks of major or non-major clinically relevant (NMCR) bleeding (HR = 0.70; 95% CI.57–0.86), major bleeding (HR = 0.70; 95%CI.53–0.92), intracranial hemorrhage (ICH) (HR = 0.42; 95%CI.24–0.74), or any bleeding (HR = 0.70;95% CI.62–0.78), but not gastrointestinal bleeding. In non-Latin American patients with AF, for the effectiveness outcomes, the use of DOACs compared with warfarin was significantly associated with decreased risks of SSE (HR = 0.87; 95%CI.75–1.00), hemorrhagic stroke (HR = 0.41; 95%CI.28–0.60), cardiovascular death (HR = 0.87; 95% CI.81–0.94), all-cause death (HR = 0.90; 95% CI.85–0.94). Conversely, the risk of myocardial infarction increased (HR = 1.34; 95% CI 1.13–1.60), but not ischemic stroke. For the safety outcomes, compared with warfarin, the use of DOACs was associated with reduced risks of major or NMCR bleeding (HR = 0.75; 95%CI.61–0.92), major bleeding (HR = 0.76; 95%CI.63–0.92), ICH (HR = 0.42; 95%CI.36–0.52), and any bleeding (HR = 0.81; 95% CI.71–0.92), but not gastrointestinal bleeding.

Conclusion

Current pooled data from the four post-hoc analyses of RCTs suggested that compared with warfarin, DOACs appeared to have significant reductions in SSE, stroke, hemorrhagic stroke, all-cause death, major or NMCR bleeding, major bleeding, ICH, and any bleeding, but comparable risks of ischemic stroke, cardiovascular death, and gastrointestinal bleeding in Latin American patients with AF. DOACs appeared to have significant reductions in SSE, hemorrhagic stroke, all-cause death, cardiovascular death, major or NMCR bleeding, major bleeding, ICH, and any bleeding, and increased the risk of myocardial infarction, but comparable risks of stroke, ischemic stroke, and gastrointestinal bleeding in non-Latin American patients with AF.

Noncanonical Effects of Oral Thrombin and Factor Xa Inhibitors in Platelet Activation and Arterial Thrombosis

Nonvitamin K oral anticoagulants (NOACs) or direct oral anticoagulants comprise inhibitors of factor Xa (rivaroxaban, apixaban, edoxaban) or factor IIa (dabigatran). Both classes efficiently interfere with the final or penultimate step of the coagulation cascade and showed superior net clinical benefit compared with vitamin K antagonists for prevention of thromboembolic events in patients with AF and for prevention and therapy of deep vein thrombosis and pulmonary embolism. None the less, accumulating data suggested, that there may be differences regarding the frequency of atherothrombotic cardiovascular events between NOACs. Thus, the optimal individualized NOAC for each patient remains a matter of debate. Against this background, some basic and translational analyses emphasized NOAC effects that impact on platelet activity and arterial thrombus formation beyond inhibition of plasmatic coagulation. In this review, we will provide an overview of the available clinical and translational evidence for so-called noncanonical NOAC effects on platelet activation and arterial thrombosis.

Non-Vitamin K Antagonist Oral Anticoagulants Versus Warfarin in Patients with Atrial Fibrillation with Coronary or Peripheral Artery Disease

The efficacy and safety of non-vitamin K antagonist oral anticoagulants (NOACs) in atrial fibrillation (AF) with coronary or peripheral artery disease (CAD or PAD) remain largely unresolved. We, therefore, conducted a meta-analysis to explore the effect of NOACs compared with warfarin in these populations.We systematically searched the Cochrane Library, PubMed, and Embase databases for randomized controlled trials (RCTs) involving NOACs versus warfarin in AF patients with CAD or PAD. A random-effect model was selected to pool the risk ratios (RRs) and 95% confidence intervals (CIs).A total of 7 RCTs were included. In AF patients with CAD, compared with warfarin use, the use of NOACs was associated with reduced risks of stroke/systemic embolism (RR 0.82; 95% CI 0.70-0.96) and intracranial hemorrhage (RR 0.41; 95% CI 0.26-0.63), but NOACs versus warfarin showed similar risks of all-cause death (RR 0.95; 95% CI 0.86-1.05), cardiovascular death (RR 0.95; 95% CI 0.80-1.13), stroke (RR 0.80; 95% CI 0.64-1.00), myocardial infarction (RR 1.00; 95% CI 0.83-1.21), and major bleeding (RR 0.82; 95% CI 0.65-1.04). Among patients with AF and PAD, NOACs versus warfarin had similar risks for stroke (RR 0.93; 95% CI 0.61-1.42), myocardial infarction (RR 1.10; 95% CI 0.64-1.90), all-cause death (RR 0.91; 95% CI 0.70-1.19), major bleeding (RR 1.12; 95% CI 0.70-1.81), and intracranial hemorrhage (RR 0.54; 95% CI 0.16-1.85).NOACs seem to be at least as effective and safe as warfarin in AF patients with CAD. whereas NOACs versus warfarin have similar efficacy and safety in patients with PAD.

Prevention of Stroke in Atrial Fibrillation After Coronary Stenting

Background and Purpose- The optimal antithrombotic strategy to balance thromboembolic and bleeding events, especially acute stroke, for patients with atrial fibrillation following coronary stenting remains a matter of debate. We conducted a network meta-analysis to identify the antithrombotic regimen associated with the lowest rate of bleeding and thromboembolic events in atrial fibrillation after coronary stenting. Methods- PubMed, Scopus, and Cochrane Central were searched for randomized controlled trials and observational studies of patients with atrial fibrillation after coronary stenting. The outcomes of interest were stroke, myocardial infarction, major adverse cardiac events, mortality, and major bleeding. A network meta-analysis was performed comparing the available antithrombotic regimens in the literature. Results- Three randomized and 15 observational studies were included, with a total of 23 478 participants. Median follow-up was 2 years. Network meta-analysis demonstrated that vitamin K antagonist plus single antiplatelet therapy or direct-acting oral anticoagulant plus single antiplatelet therapy were the most effective regimens in preventing stroke. Direct-acting oral anticoagulant regimens were associated with lower major bleeding rates than vitamin K antagonist regimens. Regimens with dual antiplatelet therapy were associated with lower rates of myocardial infarction. Vitamin K antagonist plus dual antiplatelet therapy was associated with a lower mortality and low-dose direct-acting oral anticoagulants with decreased major cardiovascular adverse events. Conclusions- Direct-acting oral anticoagulant regimens were associated with less major bleeding and major cardiovascular adverse events, but vitamin K antagonists were associated with decreased mortality and stroke. These results suggest that the decision of antithrombotic therapy in patients with atrial fibrillation after percutaneous coronary intervention needs to be individualized.

Safety and Efficacy of Triple Antithrombotic Therapy with Dabigatran versus Vitamin K Antagonist in Atrial Fibrillation Patients: A Pilot Study

Background

Combination of dual antiplatelet (DAPT) and oral anticoagulation therapy is required to decrease cardioembolic stroke and stent thrombosis risk in patients with atrial fibrillation (AF) and acute coronary syndrome (ACS). We compared the safety and efficacy of dabigatran etexilate with vitamin K antagonist (VKA), in combination with DAPT (aspirin plus clopidogrel) treatment in AF patients who underwent percutaneous coronary intervention (PCI) with stenting for ACS.

Methods

Consecutive nonvalvular AF patients who received twice-daily dabigatran 110 mg (n = 389) or VKA (n = 510) and DAPT were included. Primary endpoints were major bleeding (safety) and the composite of ischemic stroke, systemic embolism, and myocardial infarction (efficacy). The secondary efficacy endpoint was hospitalization for cardiovascular disease.

Results

After propensity score matching, comparative treatment groups comprised 175 dabigatran recipients and 175 VKA recipients. The cumulative incidence of major bleeding was lower in the dabigatran group (2.3%) compared with the VKA group (10.3%) with a hazard ratio (HR) of 4.81 [95% confidence interval (CI) 1.6-14.2, p < 0.005]. The cumulative incidence of thromboembolic events with dabigatran was slightly higher (8.0%) than with VKA (6.85%), but not statistically significantly so (0.8, 0.39-1.8; p = 0.6). Cumulative incidence of hospitalization for cardiovascular disease was lower with dabigatran (10.3%) compared with VKA (20.6%) treatment (2.2, 1.25-3.8; p < 0.006).

Conclusion

Dabigatran at the dose used for stroke prevention appears safer than VKA and maintains a similar efficacy profile, when used with DAPT, in AF patients who have undergone PCI with stenting for ACS.