Tailoring Antiplatelet Therapy in Patients Undergoing Transcatheter Aortic Valve Replacement: Navigating the Unknown

Optimal Anticoagulation on TAVI Patients Based on Thrombotic and Bleeding Risk and the Challenge Beyond: A Systematic Review and Meta-Analysis

Transcatheter Aortic Valve Replacement (TAVR) has been established as the treatment of choice for symptomatic aortic stenosis, while it is expanding in all risk-related group categories of patients, gaining gradually ground over the surgical approach. However, complications and adverse events are yet to be effectively limited and diminished with thrombotic and hemorrhagic events being rooted as a crucial topic of discussion. Favorable anticoagulation pharmacotherapy options are constantly being revised and tested, whilst guidelines are being modified to meet current clinical evidence. This review aims to systematically assess already existing guidelines on anticoagulation in post-TAVI patients and examine novel regimens for the specific use, like apixaban, rivaroxaban, and other anticoagulants, essentially constructing a holistic point of view on future progress on this matter. The added complexity brought by coagulation-affecting comorbidities such as atrial fibrillation, coronary artery disease, and more contributes to the direct association of the topic to the quality of healthcare as a public service. The literature was systematically searched to examine the effectiveness and safety of various anticoagulation treatments and cross-evaluate them based on the according category of patients that were assigned to. Clinical trials, observational studies and systematic reviews were included and, eventually, conclusive remarks and future considerations were developed and presented. In the category of patients without prior indication to anticoagulation, SAPT was proven safer and still effective, when antiplatelet therapies were compared, while a comparison of antiplatelet versus anticoagulation strategies noted the first one, with limited data, as the optimal one. Lastly, direct oral anticoagulants were shown to be safe substitutes for vitamin K antagonists for patients with prior indication to anticoagulation.

No Antithrombotic Therapy After Transcatheter Aortic Valve Replacement: Insight From the OCEAN-TAVI Registry

BACKGROUND

Several trials demonstrated that aspirin monotherapy compared with aspirin plus clopidogrel is associated with a lower incidence of bleeding without an increased risk of ischemic events in patients after transcatheter aortic valve replacement (TAVR); however, there remains a paucity of data to prove the necessity of even aspirin monotherapy.

OBJECTIVES

This study aimed to compare clinical outcomes and valve performance of the 3 different antithrombotic strategies post-TAVR from the OCEAN-TAVI (Optimized transCathEter vAlvular iNtervention) registry.

METHODS

Patients who received anticoagulation or had procedural complications were excluded. The remaining patients were classified into 3 groups according to the antithrombotic regimen at discharge: 1) nonantithrombotic therapy (None); 2) single-antiplatelet therapy (SAPT); and 3) dual-antiplatelet therapy (DAPT). The primary outcome was the incidence of net adverse clinical events (NACEs) (ie, cardiovascular death, stroke, myocardial infarction, and life-threatening or major bleeding).

RESULTS

Overall, 3,575 TAVR patients were included (None, 293; SAPT, 1,354; DAPT, 1,928). The median follow-up period was 841 days (IQR: 597-1,340 days). The incidence of NACEs did not differ between the groups (None vs SAPT: adjusted HR [aHR]: 1.18; P = 0.45; None vs DAPT: aHR: 1.09; P = 0.67). There was a lower incidence of all bleeding in patients with no antithrombotics (None vs SAPT: aHR: 0.63; P = 0.12; None vs DAPT: aHR: 0.51; P = 0.04). The valve performance was similar among the groups. Leaflet thrombosis was detected in 8.5% of the nonantithrombotic group.

CONCLUSIONS

Compared with SAPT/DAPT, the nonantithrombotic strategy was not associated with an increased risk of NACEs and potentially reduced the risk of bleeding events. The nonantithrombotic strategy may be an acceptable alternative to SAPT/DAPT in selected patients with TAVR.

Antithrombotic Therapy After Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR) is a treatment option for symptomatic patients with severe aortic stenosis who are candidates for a bioprosthesis across the entire spectrum of risk. However, TAVR carries a risk for thrombotic and bleeding events, underscoring the importance of defining the optimal adjuvant antithrombotic regimen. Antithrombotic considerations are convoluted by the fact that many patients undergoing TAVR are generally elderly and present with multiple comorbidities, including conditions that may require long-term oral anticoagulation (OAC) (eg, atrial fibrillation) and antiplatelet therapy (eg, coronary artery disease). After TAVR among patients without baseline indications for OAC, recent data suggest dual-antiplatelet therapy to be associated with an increased risk for bleeding events, particularly early postprocedure, compared with single-antiplatelet therapy with aspirin. Concerns surrounding the potential for thrombotic complications have raised the hypothesis of adjunctive use of OAC for patients with no baseline indications for anticoagulation. Although effective in modulating thrombus formation at the valve level, the bleeding hazard has shown to be unacceptably high, and the net benefit of combining antiplatelet and OAC therapy is unproven. For patients with indications for the use of long-term OAC, such as those with atrial fibrillation, the adjunctive use of antiplatelet therapy increases bleeding. Whether direct oral anticoagulant agents achieve better outcomes than vitamin K antagonists remains under investigation. Overall, single-antiplatelet therapy and OAC appear to be reasonable strategies in patients without and with indications for concurrent anticoagulation. The aim of the present review is to appraise the current published research and recommendations surrounding the management of antithrombotic therapy after TAVR, with perspectives on evolving paradigms and ongoing trials.

Aspirin Versus Clopidogrel as Single Antithrombotic Therapy After Transcatheter Aortic Valve Replacement: Insight From the OCEAN-TAVI Registry

[Figure: see text].

Transcatheter aortic valve implantation induces transient drop in platelet reactivity

ABSTRACT

Although recent studies described platelet reactivity (PR) changes in days following transcatheter aortic valve implantation (TAVI), precise time course and duration of these changes have not been fully investigated. The aim of this study was to investigate PR pattern during and after TAVI in multiple time points. Study included 40 consecutive patients undergoing TAVI. All patients underwent the procedure on dual antiplatelet therapy. PR was measured in seven time points: before induction of anaesthesia (T1), after heparin administration (T2), 10 minutes after initial valve implantation (T3), at the end of procedure (T4), and on 3rd, 6th and 30th postoperative day (T 5-7). PR was measured using impedance aggregometer using three different platelet aggregation agonists (arachidonic acid in ASPItest, adenosine diphosphate in ADPtest and thrombin receptor activating peptide 6 in TRAPtest). All patients underwent successful TAVI procedure. Mean PR on T1 was 22.9±23.0 U for ASPItest, 40.5±23.7 U for ADPtest and 91.7±32.5 U for TRAPtest. There was no significant difference in PR on T2. On T3, significant reduction of PR in all three tests was observed (ASPI 10.4±11.6 U (p=0.001), ADP 24.2±14.1 U (p<0.001) and TRAP 69.3±26.6 U (p<0.001)). PR nadir for all tests was reached on T5, with subsequent PR incline. PR values in all tests returned to baseline levels on T7. Our results show that successful TAVI procedure induces transient decrease in PR regardless of the platelet activation pathway.

Anticoagulation after Transcatheter Aortic Valve Implantation: Current Status

Transcatheter aortic valve implantation (TAVI) is the standard of care for symptomatic severe aortic stenosis. Antithrombotic therapy is required after TAVI to prevent thrombotic complications but it increases the risk of bleeding events. Current clinical guidelines are mostly driven by expert opinion and therefore yield low-grade recommendations. The optimal antithrombotic regimen following TAVI has yet to be determined and several randomised controlled trials assessing this issue are ongoing. The purpose of this article is to critically explore the impact of antithrombotic drugs, especially anticoagulants, on long-term clinical outcomes following successful TAVI.

Between a Rock and a Hard Place: How to Use Antithrombotics in Patients Undergoing Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR) has become the preferred method for management of severe aortic stenosis in patients who are at high and intermediate surgical risk, and has recently gained approval from the Food and Drug Administration in the US for use in patients at low risk for surgery. Thrombocytopenia and thromboembolic events in patients undergoing TAVR is associated with increased morbidity and mortality, and yet there is insufficient evidence supporting the current guideline-mediated therapy for antithrombotics post-TAVR. In this article, the authors review current guidelines for antithrombotic therapy in patients undergoing TAVR, studies evaluating antiplatelet regimens, and studies evaluating the use of platelet function testing after TAVR. They also offer a potential link between thrombocytopenia and antiplatelet treatments in patients undergoing TAVR.

Antithrombotic pharmacotherapy after transcatheter aortic valve implantation: an update

Introduction: Transcatheter aortic valve implantation (TAVI) is the treatment of choice for a large proportion of patients with severe aortic stenosis. Despite numerous technological and clinical advances, TAVI remains associated with thrombotic complications requiring antithrombotic pharmacotherapy, which exposes to the risk of bleeding, especially in elderly individuals. The optimal antithrombotic regimen following TAVI is uncertain and several investigations are ongoing. Areas covered: Clinical guidelines are mostly driven by observational trials and experts' opinions, thus resulting into low-grade level of evidence. The aim of the current review is to critically explore the epidemiology, pathophysiology and prognostic value of thrombotic and bleeding events after TAVI, and to review the current literature on antithrombotic strategies following the procedure. Expert opinion: Thrombotic and bleeding events remain major complications occurring in the frail population that is currently offered TAVI. Waiting for upcoming evidence from ongoing randomized clinical trials, tailoring antithrombotic therapies based on patients' characteristics, values and circumstances is a preferable approach.