Antithrombotic therapy after transcatheter aortic valve implantation: a new piece of the still unresolved puzzle

Direct oral anticoagulant versus antiplatelet therapy following transcatheter aortic valve replacement in patients without prior or concurrent indication for anticoagulation: A meta-analysis of randomized studies

INTRODUCTION

The antithrombotic management following transcatheter aortic valve replacement (TAVR) in patients who do not have a concurrent indication for long-term anticoagulation therapy is an ongoing source of debate.

METHODS

We performed a systematic review and meta-analysis to compare direct oral anticoagulants (DOACs) versus antiplatelet therapy after TAVR in patients without a concomitant indication for chronic oral anticoagulation. PubMed, Embase, and Cochrane databases were searched. Only randomized controlled trials were included. Risk ratios (RR) with p < 0.05 were considered statistically significant.

RESULTS

Three studies were included, with 2922 patients who underwent TAVR, of whom 1463 (50.1%) received DOACs. Patients who received DOACs therapy had significantly higher all-cause mortality (RR: 1.68; 95% confidence intervals [CI]: 1.22-2.30; p = 0.001) and non-cardiovascular mortality (RR: 2.33; 95% CI: 1.13-4.80; p = 0.02). The incidence of major bleeding was not significantly different between the groups (5.3% vs. 3.8%; RR: 1.44; 95% CI: 0.90-2.32; p = 0.13). There was no difference between DOACs and antiplatelet therapy in terms of: ischemic stroke (RR: 1.28; 95% CI: 0.76-2.15; p = 0.35) and cardiovascular mortality (RR: 1.36; 95% CI: 0.92-2.03; p = 0.13). Lastly, the DOACs group had a significantly lower risk of valve thrombosis than the antiplatelet group (0.8% vs. 3.2%; RR: 0.27; 95% CI: 0.14-0.51; p < 0.0001).

CONCLUSION

In this meta-analysis of randomized studies comparing DOACs to antiplatelet therapy after TAVR in patients without a concomitant indication for anticoagulation, DOACs were associated with a lower incidence of valve thrombosis and a higher rate of all-cause mortality, driven by an increase in noncardiac causes of death.

Safety and Efficacy of Double Antithrombotic Therapy With Non-Vitamin K Antagonist Oral Anticoagulants in Patients With Atrial Fibrillation Undergoing Percutaneous Coronary Intervention: A Systematic Review and Meta-Analysis

Background The optimal antithrombotic therapy for patients with atrial fibrillation undergoing percutaneous coronary intervention is a topic of debate. We aimed at defining the efficacy and safety of double antithrombotic therapy with single antiplatelet therapy (SAPT) plus a non-vitamin K antagonist oral anticoagulant (NOAC) against triple antithrombotic therapy with dual antiplatelet therapy (DAPT) added to a vitamin K antagonist (VKA), illustrating the pooled cumulative distribution of events, the ranking of different NOACs tested in NOAC+SAPT combination strategies, and the state of the current evidence in the field. Methods and Results Randomized controlled trials meeting the inclusion criteria were identified. The primary efficacy end point was the composite of trial-defined major adverse cardiac events. The primary safety end point was clinically significant bleeding. Secondary end points were the components of primary end points. Trial-level pairwise and Bayesian network meta-analyses, reconstructed Kaplan-Meier analyses, and trial sequential analysis were performed. Four randomized controlled trials (10 969 patients) were included. No differences were found in terms of major adverse cardiac events (hazard ratio [HR], 1.07; 95% CI, 0.94-1.22), and the NOAC+SAPT strategy showed a lower rate of clinically significant bleeding compared with VKA + DAPT (HR, 0.56; 95% CI, 0.39-0.80). These results were consistent in reconstructed Kaplan-Meier analyses. In the Bayesian network meta-analysis, different NOACs displayed diverse risk-benefit profiles. Trial sequential analyses suggest that the evidence for the similarity in major adverse cardiac events compared with VKA + DAPT and the bleeding risk reduction observed with NOAC+SAPT is likely to be conclusive. Conclusions NOAC+SAPT does not increase the risk of major adverse cardiac events and reduces the risk of bleeding compared with VKA + DAPT in AF patients undergoing percutaneous coronary intervention. Various NOACs may have different risk-benefit profiles in combination strategies. Registration URL: https://www.crd.york.ac.uk/prospero/; Unique identifier: CRD42020151089.

Novel Perspective for Antithrombotic Therapy in TAVI

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While surgical aortic valve replacement (SAVR) was for years the only available treatment for symptomatic aortic stenosis, the introduction of transcatheter aortic valve implantation (TAVI) in 2002 and the improvement of its technical aspects in the following years, has holistically changed the synchronous therapeutic approach of aortic valve stenosis. Recent evidence has expanded the indication of TAVI from high to lower surgical risk populations with symptomatic aortic stenosis. The administration of antithrombotic therapy periprocedurally and its maintenance after a successful TAVI is crucial for the prevention of complications and affects postprocedural survival. Randomized controlled trials investigating the appropriate combination and the duration of antithrombotic treatment after TAVI are for the moment scarce. This review article sheds light on the underlying pathogenetic mechanisms contributing in periprocedural TAVI thrombotic complications and discuss the efficacy of current antithrombotic policies as evaluated in randomized trials.

Thromboembolic and Bleeding Complications in Transcatheter Aortic Valve Implantation: Insights on Mechanisms, Prophylaxis and Therapy

Transcatheter aortic valve implantation (TAVI) has emerged as an important alternative to surgical aortic valve repair (SAVR) for patients with severe aortic stenosis. This rapidly advancing field has produced new-generation devices being delivered with small delivery sheaths, embolic protection devices and improved retrieval features. Despite efforts to reduce the rate of thrombotic complications associated with TAVI, valve thrombosis and cerebral ischaemic events post-TAVI continue to be a significant issue. However, the antithrombotic treatments utilised to prevent these dreaded complications are based on weak evidence and are associated with high rates of bleeding, which in itself is associated with adverse clinical outcomes. Recently, experimental data has shed light on the unique mechanisms, particularly the complex haemodynamic changes at sites of TAVI, that underpin the development of post-TAVI thrombosis. These new insights regarding the drivers of TAVI-associated thrombosis, coupled with the ongoing development of novel antithrombotics which do not cause bleeding, hold the potential to deliver newer, safer therapeutic paradigms to prevent post-TAVI thrombotic and bleeding complications. This review highlights the major challenge of post-TAVI thrombosis and bleeding, and the significant issues surrounding current antithrombotic approaches. Moreover, a detailed discussion regarding the mechanisms of post-TAVI thrombosis is provided, in addition to an appraisal of current antithrombotic guidelines, past and ongoing clinical trials, and how novel therapeutics offer the hope of optimizing antithrombotic strategies and ultimately improving patient outcomes.