Antithrombotic Therapy After Transcatheter Aortic Valve Replacement

Impact of balloon post-dilation on valve durability and long-term clinical outcomes after self-expanding transcatheter aortic valve implantation

BACKGROUND

Balloon post-dilation (BPD) is a widely adopted strategy to optimize acute results of TAVI, with a positive impact on both paravalvular leak and mean gradients. On the other hand, the inflation of the balloon inside prosthetic leaflets may damage them increasing the risk of structural valve deterioration (SVD). Furthermore, the impact of BPD on long-term clinical outcomes and valve hemodynamics is yet unknown.

AIMS

To evaluate the impact of BPD on valve durability and long-term clinical outcomes in patients undergoing self-expanding transcatheter valve implantation (TAVI).

METHODS

Echocardiographic and clinical data from the ClinicalService (a nation-based data repository and medical care project) were analyzed. Patients were divided into two groups, those who underwent BPD after TAVI and those who did not. Coprimary endpoints were all-cause death and SVD. Cumulative incidence functions for SVD were estimated.

RESULTS

Among 1835 patients included in the study, 417 (22.7%) underwent BPD and 1418 (77.3%) did not undergo BPD. No statistically significant differences at 6-year follow-up were found between groups in terms of all-cause mortality (HR: 1.05, 95% CI: 0.9-1.22; p = 0.557) and SVD (2.1% vs. 1.4%, p = 0.381). In addition, BPD did not predispose to higher risk of cardiovascular death, myocardial infarction, valve thrombosis, and endocarditis at 6-year follow-up.

CONCLUSIONS

BPD following TAVI with a self-expanding prosthesis does not seem to be associated with an increased risk of adverse clinical outcomes or SVD at 6-year follow-up.

Addressing the longitudinal components of surgical treatments

Despite their pre- and postoperative components, surgical treatment strategies have typically been cast as point interventions in causal inference research. When longitudinal perioperative components affect outcomes of interest, leaving them unspecified or failing to measure adherence to them complicates the interpretation of effect estimates. Inspired by two recent landmark trials that assessed the risk of stroke or death after transcatheter aortic valve replacement (TAVR) compared with surgical aortic valve replacement (SAVR), the PARTNER 3 trial and the Evolut Low Risk trial, we discuss possible ways that different postoperative therapies in treatment arms and incomplete adherence to those therapies can impact the interpretation of intention-to-treat effect estimates in surgical trials. We argue that surgical treatments are not necessarily point interventions, and make recommendations for improving the design and analysis of trials involving surgical interventions. Central to these recommendations is the need for investigators to specify and report adherence to longitudinal perioperative treatment components.

Cerebral embolic protection during transcatheter heart interventions

Stroke remains a devastating complication of transcatheter aortic valve replacement (TAVR), with the incidence of clinically apparent stroke seemingly fixed at around 3% despite TAVR's significant evolution during the past decade. Embolic showers of debris (calcium, atheroma, valve material, foreign material) are captured in the majority of patients who have TAVR using a filter-based cerebral embolic protection device (CEPD). Additionally, in systematic brain imaging studies, the majority of patients receiving TAVR exhibit new cerebral lesions. Mechanistic studies have shown reductions in the volume of new cerebral lesions using CEPDs, yet the first randomised trial powered for periprocedural stroke within 72 hours of a transfemoral TAVR failed to meet its primary endpoint of showing superiority of the SENTINEL CEPD. The present review summarises the clinicopathological rationale for the development of CEPDs, the evidence behind these devices to date and the emerging recognition of cerebral embolisation in many non-TAVR transcatheter procedures. Given the uniqueness of each of the various CEPDs under development, specific trials tailored to their designs will need to be undertaken to broaden the CEPD field, in addition to evaluating the role of CEPD in non-TAVR transcatheter heart interventions. Importantly, the cost-effectiveness of these devices will require assessment to broaden the adoption of CEPDs globally.

Inflammatory Status Assessment by Machine Learning Techniques to Predict Outcomes in Patients with Symptomatic Aortic Stenosis Treated by Transcatheter Aortic Valve Replacement

(1) Background: Although transcatheter aortic valve replacement (TAVR) significantly improves long-term outcomes of symptomatic severe aortic stenosis (AS) patients, long-term mortality rates are still high. The aim of our study was to identify potential inflammatory biomarkers with predictive capacity for post-TAVR adverse events from a wide panel of routine biomarkers by employing ML techniques. (2) Methods: All patients diagnosed with symptomatic severe AS and treated by TAVR since January 2016 in a tertiary center were included in the present study. Three separate analyses were performed: (a) using only inflammatory biomarkers, (b) using inflammatory biomarkers, age, creatinine, and left ventricular ejection fraction (LVEF), and (c) using all collected parameters. (3) Results: A total of 338 patients were included in the study, of which 56 (16.5%) patients died during follow-up. Inflammatory biomarkers assessed using ML techniques have predictive value for adverse events post-TAVR with an AUC-ROC of 0.743 and an AUC-PR of 0.329; most important variables were CRP, WBC count and Neu/Lym ratio. When adding age, creatinine and LVEF to inflammatory panel, the ML performance increased to an AUC-ROC of 0.860 and an AUC-PR of 0.574; even though LVEF was the most important predictor, inflammatory parameters retained their value. When using the entire dataset (inflammatory parameters and complete patient characteristics), the ML performance was the highest with an AUC-ROC of 0.916 and an AUC-PR of 0.676; in this setting, the CRP and Neu/Lym ratio were also among the most important predictors of events. (4) Conclusions: ML models identified the CRP, Neu/Lym ratio, WBC count and fibrinogen as important variables for adverse events post-TAVR.

Platelet and Monocyte Activation After Transcatheter Aortic Valve Replacement (POTENT-TAVR): A Mechanistic Randomized Trial of Ticagrelor Versus Clopidogrel

Background

Inflammation and thrombosis are often linked mechanistically and are associated with adverse events after transcatheter aortic valve replacement (TAVR). High residual platelet reactivity (HRPR) is especially common when clopidogrel is used in this setting, but its relevance to immune activation is unknown. We sought to determine whether residual activity at the purinergic receptor P2Y12 (P2Y12) promotes prothrombotic immune activation in the setting of TAVR.

Methods

This was a randomized trial of 60 patients (enrolled July 2015 through December 2018) assigned to clopidogrel (300mg load, 75mg daily) or ticagrelor (180mg load, 90 mg twice daily) before and for 30 days following TAVR. Co-primary endpoints were P2Y12-dependent platelet activity (Platelet Reactivity Units; VerifyNow) and the proportion of inflammatory (cluster of differentiation [CD] 14+/CD16+) monocytes 1 day after TAVR.

Results

Compared to clopidogrel, those randomized to ticagrelor had greater platelet inhibition (median Platelet Reactivity Unit [interquartile range]: (234 [170.0-282.3] vs. 128.5 [86.5-156.5], p < 0.001), but similar inflammatory monocyte proportions (22.2% [18.0%-30.2%] vs. 25.1% [22.1%-31.0%], p = 0.201) 1 day after TAVR. Circulating monocyte-platelet aggregates, soluble CD14 levels, interleukin 6 and 8 levels, and D-dimers were also similar across treatment groups. HRPR was observed in 63% of the clopidogrel arm and was associated with higher inflammatory monocyte proportions. Major bleeding events, pacemaker placement, and mortality did not differ by treatment assignment.

Conclusions

Residual P2Y12 activity after TAVR is common in those treated with clopidogrel but ticagrelor does not significantly alter biomarkers of prothrombotic immune activation. HRPR appears to be an indicator (not a cause) of innate immune activation in this setting.

Case report: acute myocardial infarction in the setting of acute transcatheter aortic valve thrombus

We describe a case of valve thrombosis and a subsequent thromboembolic event within only 10 days of transcatheter aortic valve implantation (TAVI). Postprocedural anticoagulants are not standard of care medications post-TAVI in patients without atrial fibrillation. Valve thrombosis is an indication to initiate anticoagulation to resolve and prevent further thrombus.

Rare Cause of Late Left Aortic Sinus Obstruction Following Transcatheter Aortic Valve Replacement

A 74-year-old woman with a history aortic stenosis with prior transcatheter aortic valve replacement presented with non-ST-segment elevation myocardial infarction secondary to a delayed left coronary sinus obstruction. With physiology and intravascular ultrasound guidance, the patient was treated with stents through the valve struts and to the left main. (Level of Difficulty: Intermediate.).

Shear-Mediated Platelet Microparticles Demonstrate Phenotypic Heterogeneity as to Morphology, Receptor Distribution, and Hemostatic Function

Implantable Cardiovascular Therapeutic Devices (CTD), while lifesaving, impart supraphysiologic shear stress to platelets, resulting in thrombotic and bleeding coagulopathy. We previously demonstrated that shear-mediated platelet dysfunction is associated with downregulation of platelet GPIb-IX-V and αIIbβ3 receptors via generation of Platelet-Derived MicroParticles (PDMPs). Here, we test the hypothesis that sheared PDMPs manifest phenotypical heterogeneity of morphology and receptor surface expression and modulate platelet hemostatic function. Human gel-filtered platelets were exposed to continuous shear stress. Alterations of platelet morphology were visualized using transmission electron microscopy. Surface expression of platelet receptors and PDMP generation were quantified by flow cytometry. Thrombin generation was quantified spectrophotometrically, and platelet aggregation was measured by optical aggregometry. Shear stress promotes notable alterations in platelet morphology and ejection of distinctive types of PDMPs. Shear-mediated microvesiculation is associated with the remodeling of platelet receptors, with PDMPs expressing significantly higher levels of adhesion receptors (αIIbβ3, GPIX, PECAM-1, P-selectin, and PSGL-1) and agonist receptors (P2Y12 and PAR1). Sheared PDMPs promote thrombin generation and inhibit platelet aggregation induced by collagen and ADP. Sheared PDMPs demonstrate phenotypic heterogeneity as to morphology and defined patterns of surface receptors and impose a bidirectional effect on platelet hemostatic function. PDMP heterogeneity suggests that a range of mechanisms are operative in the microvesiculation process, contributing to CTD coagulopathy and posing opportunities for therapeutic manipulation.

Safety and Effectiveness of Evolocumab During Acute and Sub-acute Phases of Acute Coronary Syndrome (ACS): A Systematic Review and Meta-analysis

BACKGROUND

Coronary artery disease (CAD), manifested mainly as acute coronary syndrome (ACS), continues to be a major cause of mortality globally and a significant contributing factor to the global disease burden. Elevation of low-density lipoprotein cholesterol levels attributed to proprotein convertase subtilisin/Kexin type-9 (PCSK9) during and following ACS puts patients at high risk of subsequent adverse events. Evolocumab is a PCSK9 inhibitor that is associated with a significant reduction in low-density lipoprotein cholesterol (LDL-C) levels through PCSK9 inhibition in comparison to traditional statin therapy.

METHODS

We conducted a systematic review and meta-analysis of literature addressing the efficacy and safety of evolocumab compared to other lipid-lowering therapies or placebo. An extensive internet-based literature search using pre-determined key phrases supported by medical sub-headings and Boolean operators was performed in October 2022 to identify literature pertinent to the research topic. The search was primarily based on the National Library of Medicine (PubMed and Clinical Trials), MEDLINE, Cochrane, and the Science direct literature databases. Subsequently, the researchers devised PICOs-based screening criteria which had to be met by each identified study for inclusion in the review and meta-analysis. Two independent reviewers conducted data stratification and quality assessment of identified studies. Statistical analysis of the primary and secondary outcomes was conducted on the Cochrane REVMAN 5.4 statistical software for randomized trials.

RESULTS

Two thousand five hundred and seventy-six potential studies were identified for inclusion in the systematic review. Data stratification, screening, and quality assessment of these studies based on the eligibility criteria led to the exclusion of two thousand five hundred and sixty-seven studies as they did not meet the standards set. Nine randomized controlled trials progressed to numerical analysis for validity and reliability. Eight studies were included in the meta-analysis. Meta-analytical results showed a significant decrease in LDL-C changes from initiation of evolocumab therapy to 8 weeks following ACS compared to placebo. Similar results were derived in the sub-acute phase of ACS [SMD -1.95 (95% CI -2.29, -1.62)]. The meta-analysis revealed no statistically significant relationship between the risk of adverse effects, serious adverse effects, and major adverse cardiovascular events (MACE) from treatment using evolocumab in comparison to placebo [(relative risk, RR 1.04 (95% CI 0.99, 1.08) (Z = 1.53; p=0.12)].

CONCLUSION

Early evolocumab therapy initiation was associated with a significant decrease in LDL-C levels and was not associated with an increased risk of adverse effects in comparison to placebo.

Shear-Mediated Platelet Microparticles Demonstrate Phenotypic Heterogeneity as to Morphology, Receptor Distribution, and Hemostatic Function

Objective

Implantable cardiovascular therapeutic devices (CTD) including stents, percutaneous heart valves and ventricular assist devices, while lifesaving, impart supraphysiologic shear stress to platelets resulting in thrombotic and bleeding device-related coagulopathy. We previously demonstrated that shear-mediated platelet dysfunction is associated with downregulation of platelet GPIb-IX-V and αIIbβ3 receptors via generation of platelet-derived microparticles (PDMPs). Here, we test the hypothesis that shear-generated PDMPs manifest phenotypical heterogeneity of their morphology and surface expression of platelet receptors, and modulate platelet hemostatic function.

Approach and Results

Human gel-filtered platelets were exposed to continuous shear stress and sonication. Alterations of platelet morphology were visualized using transmission electron microscopy. Surface expression of platelet receptors and PDMP generation were quantified by flow cytometry. Thrombin generation was quantified spectrophotometrically, and platelet aggregation in plasma was measured by optical aggregometry. We demonstrate that platelet exposure to shear stress promotes notable alterations in platelet morphology and ejection of several distinctive types of PDMPs. Shear-mediated microvesiculation is associated with the differential remodeling of platelet receptors with PDMPs expressing significantly higher levels of both adhesion (α _IIb β ₃ , GPIX, PECAM-1, P-selectin, and PSGL-1) and agonist-evoked receptors (P ₂ Y ₁₂ & PAR1). Shear-mediated PDMPs have a bidirectional effect on platelet hemostatic function, promoting thrombin generation and inhibiting platelet aggregation induced by collagen and ADP.

Conclusions

Shear-generated PDMPs demonstrate phenotypic heterogeneity as to morphologic features and defined patterns of surface receptor alteration, and impose a bidirectional effect on platelet hemostatic function. PDMP heterogeneity suggests that a range of mechanisms are operative in the microvesiculation process, contributing to CTD coagulopathy and posing opportunities for therapeutic manipulation.

[How to select the best device using pre-TAVR CT scan]

Transcatheter aortic valve replacement or TAVR has become the gold standard for the treatment of symptomatic and severe aortic valve stenosis in elderly patients. Although the role of computed tomography imaging was initially limited to the determination of the optimal vascular approach, it has progressively matured to become the pilar of TAVR work-up while being standardized by consensus conferences. The list of evaluated elements includes aortic annulus diameter, the optimal projection curve, the number of aortic leaflets, the severity and localization of calcifications, coronary ostial height, membranous septum length and aortic angulation. The proper and cautious evaluation of these elements may help evaluating the risk for the main periprocedural complications such as coronary obstruction, annular rupture, permanent pacemaker implantation or procedural failure and selecting the optimal transcatheter heart valve and its size, according to the patient's specific anatomy. In this review, we detail how the evaluation of these parameters may impact the selection of the transcatheter heart valve.

Stroke prevention during and after transcatheter aortic valve implantation: From cerebral protection devices to antithrombotic management

Since its conception, transcatheter aortic valve implantation (TAVI) has undergone important improvements both in the implantation technique and in transcatheter devices, allowing an enthusiastic adoption of this therapeutic approach in a wide population of patients previously without a surgical option and managed conservatively. Nowadays, patients with severe symptomatic aortic stenosis are typically managed with TAVI, regardless of their risk to surgery, improving the prognosis of patients and thus achieving an exponential global expansion of its use. However, thromboembolic and hemorrhagic complications remain a latent concern in TAVI recipients. Both complications can appear simultaneously in the periprocedural period or during the follow-up, and when minor, they resolved without apparent sequelae, but in a relevant percentage of cases, they are devastating, overshadowing the benefit achieved with TAVI. Our review outlines the etiology and incidence of thromboembolic complications associated with TAVI, the main current strategies for their prevention, and the implications of its pharmacological management at the follow-up in a TAVI population, mostly frail and predisposed to bleeding complications.

Antithrombotic Therapy After Transcatheter Aortic Valve Replacement: An Overview

Transcatheter aortic valve replacement (TAVR) is an established procedure for the treatment of patients with severe aortic stenosis. The optimal antithrombotic regimen following TAVR, currently unknown and inconsistently applied, is impacted by thromboembolic risk, frailty, bleeding risk, and comorbidities. There is a quickly growing body of literature examining the complex issues underlying antithrombotic regimens post-TAVR. This review provides an overview of thromboembolic and bleeding events following TAVR, summarizes the evidence regarding optimal antiplatelet and anticoagulant use post-TAVR, and highlights current challenges and future directions. By understanding appropriate indications and outcomes associated with different antithrombotic regimens post-TAVR, morbidity and mortality can be minimized in a generally frail and elderly patient population.

Apixaban and Valve Thrombosis After Transcatheter Aortic Valve Replacement: The ATLANTIS-4D-CT Randomized Clinical Trial Substudy

BACKGROUND

Subclinical obstructive valve thrombosis after transcatheter aortic valve replacement (TAVR) is of uncertain frequency and clinical impact.

OBJECTIVES

The aim of this study was to determine the effects of apixaban vs standard of care on post-TAVR valve thrombosis detected by 4-dimensional (4D) computed tomography.

METHODS

The randomized ATLANTIS (Anti-Thrombotic Strategy to Lower All Cardiovascular and Neurologic Ischemic and Hemorrhagic Events After Trans-Aortic Valve Implantation for Aortic Stenosis) trial demonstrated that apixaban 5 mg twice daily was not superior to standard of care (vitamin K antagonists or antiplatelet therapy) after successful TAVR and was associated with similar safety but with more noncardiovascular deaths. Three months after randomization, 4D computed tomography was proposed to all patients to determine the percentage of patients with ≥1 prosthetic valve leaflet with grade 3 or 4 reduced leaflet motion or grade 3 or 4 hypoattenuated leaflet thickening (the primary endpoint) in the intention-to-treat population.

RESULTS

Seven hundred sixty-two participants had complete multiphase datasets and were included in the 4D computed tomographic analysis. The primary endpoint occurred in 33 (8.9%) and 51 (13.0%) patients in the apixaban and standard-of-care groups, respectively. It was reduced with apixaban vs antiplatelet therapy (OR: 0.51; 95% CI: 0.30-0.86) but not vs vitamin K antagonists (OR: 1.80; 95% CI: 0.62-5.25) (P_interaction = 0.037). The composite of death, myocardial infarction, any stroke, or systemic embolism at 1 year occurred in 10.7% (n = 9 of 84) and 7.1% (n = 48 of 178) of patients with and without subclinical valve thrombosis at 90 days, respectively (HR: 1.68; 95% CI: 0.82-3.44).

CONCLUSIONS

Apixaban reduced subclinical obstructive valve thrombosis in the majority of patients who underwent TAVR without having an established indication for anticoagulation. This study was not powered for clinical outcomes. (Anti-Thrombotic Strategy After Trans-Aortic Valve Implantation for Aortic Stenosis [ATLANTIS]; NCT02664649).

Biomechanics of Transcatheter Aortic Valve Replacement Complications and Computational Predictive Modeling

Transcatheter aortic valve replacement (TAVR) is a rapidly growing field enabling replacement of diseased aortic valves without the need for open heart surgery. However, due to the nature of the procedure and nonremoval of the diseased tissue, there are rates of complications ranging from tissue rupture and coronary obstruction to paravalvular leak, valve thrombosis, and permanent pacemaker implantation. In recent years, computational modeling has shown a great deal of promise in its capabilities to understand the biomechanical implications of TAVR as well as help preoperatively predict risks inherent to device-patient-specific anatomy biomechanical interaction. This includes intricate replication of stent and leaflet designs and tested and validated simulated deployments with structural and fluid mechanical simulations. This review outlines current biomechanical understanding of device-related complications from TAVR and related predictive strategies using computational modeling. An outlook on future modeling strategies highlighting reduced order modeling which could significantly reduce the high time and cost that are required for computational prediction of TAVR outcomes is presented in this review paper. A summary of current commercial/in-development software is presented in the final section.

Post-Discharge Antithrombotic Therapy Following Transcatheter Aortic Valve Implantation in Australian Patients

BACKGROUND

Guidelines recommend antithrombotic therapy for patients following transcatheter aortic valve implantation (TAVI) to reduce the risk of ischaemic events and bioprosthetic valve thrombosis.

OBJECTIVE

To describe antithrombotic dispensing within 30 days of discharge for Australian patients receiving TAVI.

METHODS

We performed a state-wide retrospective cohort study using linked hospital and medicines dispensing data from January 2013 to December 2018 for all patients receiving TAVI in New South Wales, Australia. We identified patients dispensed oral anticoagulants (vitamin K antagonists [warfarin], direct oral anticoagulants [DOACs]) or clopidogrel within 30 days of discharge. We examined demographic and clinical predictors of antithrombotic dispensing.

RESULTS

Our cohort comprised 1,217 patients who underwent TAVI; median age was 84 years and 707 (58.1%) were male. Of these, 808 patients (66.4%) had an antithrombotic dispensed within 30 days of hospital discharge. One-third (33.7%) of these patients were dispensed an anticoagulant (16.1% warfarin; 17.6% DOACs) and two-thirds (66.3%) were dispensed clopidogrel. Patients undergoing TAVI were more likely to be dispensed an antithrombotic medicine within 30-days of hospital discharge if they had been dispensed antithrombotic medicines (RR 1.07; 95% CI 1.03-1.11) or angiotensin-converting-enzyme inhibitors/angiotensin II receptor blockers (RR 1.04; 95% CI 1.00-1.07) in the 6 months prior to admission. Patients with a history of haemorrhage were less likely to be dispensed an antithrombotic medicine within 30 days of hospital discharge (RR 0.93; 95% CI 0.89-0.98).

CONCLUSIONS

We observed gaps in best evidence pharmacotherapy for patients post-TAVI, with almost one third of patients not receiving antithrombotic medicines post-discharge. Further research is needed to quantify the impact of emerging clinical guidelines recommending single antiplatelet therapy, on adherence to best-practice care.

Circulating Monocyte Subsets and Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR), as an alternative to open heart surgery, has revolutionized the treatment of severe aortic valve stenosis (AVS), the most common valvular disorder in the elderly. AVS is now considered a form of atherosclerosis and, like the latter, partly of inflammatory origin. Patients with high-grade AVS have a highly disturbed blood flow associated with high levels of shear stress. The immediate reopening of the valve during TAVR leads to a sudden restoration of a normal blood flow hemodynamic. Despite its good prognosis for patients, TAVR remains associated with bleeding or thrombotic postprocedural complications, involving mechanisms that are still poorly understood. Many studies report the close link between blood coagulation and inflammation, termed thromboinflammation, including monocytes as a major actor. The TAVR procedure represents a unique opportunity to study the influence of shear stress on human monocytes, key mediators of inflammation and hemostasis processes. The purpose of this study was to conduct a review of the literature to provide a comprehensive overview of the impact of TAVR on monocyte phenotype and subset repartition and the association of these parameters with the clinical outcomes of patients with severe AVS who underwent TAVR.

Antithrombotic Therapy Following Transcatheter Aortic Valve Replacement

Due to a large technical improvement in the past decade, transcatheter aortic valve replacement (TAVR) has expanded to lower-surgical-risk patients with symptomatic and severe aortic stenosis. While mortality rates related to TAVR are decreasing, the prognosis of patients is still impacted by ischemic and bleeding complications, and defining the optimal antithrombotic regimen remains a priority. Recent randomized control trials reported lower bleeding rates with an equivalent risk in ischemic outcomes with single antiplatelet therapy (SAPT) when compared to dual antiplatelet therapy (DAPT) in patients without an underlying indication for anticoagulation. In patients requiring lifelong oral anticoagulation (OAC), the association of OAC plus antiplatelet therapy leads to a higher risk of bleeding events with no advantages on mortality or ischemic outcomes. Considering these data, guidelines have recently been updated and now recommend SAPT and OAC alone for TAVR patients without and with a long-term indication for anticoagulation. Whether a direct oral anticoagulant or vitamin K antagonist provides better outcomes in patients in need of anticoagulation remains uncertain, as recent trials showed a similar impact on ischemic and bleeding outcomes with apixaban but higher gastrointestinal bleeding with edoxaban. This review aims to summarize the most recently published data in the field, as well as describe unresolved issues.

[Aortic stenosis: An update]

Aortic stenosis remains one of the most frequent valvulopathy worldwide, burdened with great mortality and morbidity, and for which there is not yet an effective preventive approach, although the pathophysiological mechanisms involved in its development are better understood nowadays. Its cure, however, has been revolutionized in the last decade by the advent of transcatheter aortic valve implantation, or TAVI (also named transcatheter aortic valve replacement or TAVR). The technique of TAVI has been refined and its indications has been extended, following the publication of large randomized controlled trials where it was compared to surgical aortic valve replacement with favorable results. Consequently, transfemoral TAVR has become the first line of treatment in case of symptomatic severe aortic valve stenosis. In this review, we describe the pathophysiological mechanisms leading to severe aortic stenosis and the main ongoing randomized controlled trials targeting them. We describe the indication for surgical or percutaneous aortic valve replacement and the main complications following the procedure.

Non-Vitamin K Oral Anticoagulant After Transcatheter Aortic Valve Replacement: A Systematic Review and Meta-Analysis

Objective: We aimed to compare non-vitamin K oral anticoagulants (NOACs) with a traditional antithrombotic such as vitamin K antagonist (VKA) and antiplatelet agents in patients after transcatheter aortic valve replacement (TAVR).

Methods: We conducted a search in PubMed, EMBASE, and the Cochrane Library until November 2021 for studies involving comparisons of any type of NOACs, including dabigatran, apixaban, rivaroxaban, and edoxaban, with VKA or antiplatelet agents after TAVR. A comparison of NOACs versus VKA was performed in patients with an indication for oral anticoagulation. In addition, we compared NOACs versus antiplatelet in patients without such indication. We calculated the hazard ratios with 95% confidence intervals (CIs) to determine long-term outcomes. The primary outcome was a combined endpoint consisting of all-cause mortality, stroke, major bleeding, or any related clinical adverse events. Secondary outcomes were all-cause mortality, major bleeding, and stroke, respectively.

Results: A total of 10 studies including 10,563 patients after TAVR were included in this meta-analysis. There were no significant differences in any of the long-term outcomes between the NOAC and VKA groups. Although there were no significant differences in the combined endpoint, major bleeding, or stroke, a significant difference was observed in the all-cause mortality (HR 1.74, 95% CI 1.25–2.43, p = 0.001) between the NOAC and antiplatelet groups.

Conclusion: For patients with an indication for oral anticoagulation after TAVR, NOACs seem to be associated with noninferior outcomes compared with VKA therapy. However, for patients without an indication for oral anticoagulation, NOACs appear to be associated with a higher risk of all-cause death as compared with antiplatelet treatment.

Systematic Review Registration:https://clinicaltrials.gov/, identifier CRD42020155122.

Use of Direct Oral Anticoagulant and Outcomes in Patients With Atrial Fibrillation after Transcatheter Aortic Valve Replacement: Insights From the STS/ACC TVT Registry

Background

Clinical evidence on the safety and effectiveness of using direct oral anticoagulants (DOACs) in patients with atrial fibrillation after transcatheter aortic valve replacement (TAVR) remains limited. The aim of this study was to investigate the trends and outcomes of using DOACs in patients with TAVR and atrial fibrillation.

Methods and Results

Data from the STS/ACC TVT (Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy) Registry was used to identify patients who underwent successful TAVR with preexisting or incident atrial fibrillation who were discharged on oral anticoagulation between January 2013 and May 2018. Patients with a mechanical valve, valve‐in‐valve procedure, or prior stroke within a year were excluded. The adjusted primary outcome was 1‐year stroke events. The adjusted secondary outcomes included bleeding, intracranial hemorrhage, and death. A total of 21 131 patients were included in the study (13 004 TAVR patients were discharged on a vitamin K antagonist and 8127 were discharged on DOACs.) The use of DOACs increased 5.5‐fold from 2013 to 2018. The 1‐year incidence of stroke was comparable between DOAC‐treated patients and vitamin K antagonist‐treated patients (2.51% versus 2.37%; hazard ratio [HR], 1.00; 95% CI, 0.81–1.23) whereas DOAC‐treated patients had lower 1‐year incidence of any bleeding (11.9% versus 15.0%; HR, 0.81; 95% CI, 0.75–0.89), intracranial hemorrhage (0.33% versus 0.59%; HR, 0.54; 95% CI, 0.33–0.87), and death (15.8% versus 18.2%; HR, 0.92; 95% CI, 0.85–1.00).

Conclusions

In patients with TAVR and atrial fibrillation, DOAC use, when compared with vitamin K antagonists, was associated with comparable stroke risk and significantly lower risks of bleeding, intracranial hemorrhage, and death at 1 year.

Efficacy and safety of antithrombotic therapy with non-vitamin K antagonist oral anticoagulants after transcatheter aortic valve replacement: a systematic review and meta-analysis

Objective:

A meta-analysis was performed to compare the efficacy and safety of antithrombotic therapy with non-vitamin K antagonist oral anticoagulants (NOACs) versus standard care in patients after successful transcatheter aortic valve replacement (TAVR).

Methods:

A systematic search of PubMed, Cochrane Central Register of Controlled Trials, and EMBASE databases and ClinicalTrials.gov website (through 21 October 2020) was performed. Risk ratios (RRs) with 95% confidence intervals (CIs) for all outcomes were calculated using random-effects models.

Results:

Twelve studies (two studies were randomized controlled trials) comprising 6943 patients were included (5299 had indications for oral anticoagulation (OAC) and 1644 had none). No significant differences were found between NOACs and the standard care in the incidences of all stroke, a composite endpoint, and major/life-threatening bleeding. NOACs were associated with lower all-cause mortality than vitamin K antagonists (VKAs) in post-TAVR patients with indications for OAC after more than 1 year of follow-up [RR = 0.64; 95% CI, (0.42, 0.96); p = 0.03], whereas NOACs exhibited poor outcomes than antiplatelet therapy (APT) in patients without indications for OAC [RR = 1.66; 95% CI, (1.12, 2.45); p = 0.01]. In the prevention of valve thrombosis, NOACs and VKAs were not significantly different in patients with indications for OAC [RR = 0.66; 95% CI, (0.24, 1.84); p = 0.43], whereas NOACs were better than APT in patients without indications for OAC [RR = 0.19; 95% CI, (0.04, 0.83); p = 0.03].

Conclusions:

In patients with indications for OAC, post-TAVR antithrombotic therapy with NOACs was more favorable due to its lower all-cause mortality after more than 1 year of follow-up. In those without indications for OAC, NOACs presented poorer outcomes due to its higher all-cause mortality.

Acute Type A Aortic Dissection Confounded by Aberrant Symptoms

Acute aortic dissection (AAD) is a cardiovascular emergency that requires emergent surgical, endovascular, or medical intervention depending on the portion of the aorta implicated, as dictated by the Stanford classification, and the extent of aortic involvement. Acute chest pain radiating to the back is typically seen in AAD and may be associated with radial pulse deficits. A high index of suspicion is required to diagnose and initiate management of this emergency as early as possible. This is a report of an atypical presentation of an extensive aortic dissection identified in a young man without most of the typical risk factors, but which was promptly diagnosed and treated.

Impact of anemia on short-term outcomes after TAVR: A subgroup analysis from the BRAVO-3 randomized trial

OBJECTIVES

To determine the prognostic impact of anemia in patients randomized to bivalirudin or unfractionated heparin (UFH) during transcatheter aortic valve replacement (TAVR).

BACKGROUND

Whether the periprocedural use of bivalirudin as compared with UFH in anemic patients undergoing TAVR has an impact on outcomes remains unknown.

METHODS

The BRAVO-3 trial compared the use of bivalirudin versus UFH in 802 high risk patients undergoing transfemoral TAVR for severe symptomatic aortic stenosis. Patients were stratified according to the presence (defined as hemoglobin levels <13 g/dl in men and <12 g/dl in women) or absence of anemia. The primary outcomes were net adverse cardiac events (NACE; a composite of all-cause mortality, myocardial infarction, stroke, or bleeding) and major bleeding (Bleeding Academic Research Consortium ≥3b) at 30 days.

RESULTS

Among 798 patients with available baseline hemoglobin levels, 427 (54%) were anemic of whom 221 (52%) received bivalirudin. There were no significant differences in NACE and major bleeding at 30 days between patients with and without anemia, irrespective of the type of anticoagulant used (p_interaction  = 0.71 for NACE, p_interaction  = 1.0 for major bleeding). However, anemic patients had a higher risk of major vascular complications (adjusted OR 2.43, 95% CI 1.42-4.16, p = 0.001), and acute kidney injury (adjusted OR 1.74, 95% CI 1.16-2.59, p = 0.007) compared to non-anemic patients at 30 days.

CONCLUSIONS

Anemia was not associated with a higher risk of NACE or major bleeding at 30 days after TAVR without modification of the treatment effects of periprocedural anticoagulation with bivalirudin versus UFH.

Impact of Comorbidities and Antiplatelet Regimen on Platelet Reactivity Levels in Patients Undergoing Transcatheter Aortic Valve Implantation

ABSTRACT

The aim of our study is to assess the impact of anemia, chronic kidney disease, and diabetes mellitus on platelet reactivity (PR) in patients with severe aortic stenosis, both at baseline and after transcatheter aortic valve implantation (TAVI). This study is a prespecified subanalysis of the REAC-TAVI prospective, multicenter trial that included patients pretreated with aspirin + clopidogrel before TAVI. PR was measured at baseline and at 5 different time points after TAVI with the VerifyNow assay (Accriva Diagnostics, San Diego, CA), over a 3-month follow-up period. Patients with high PR (HPR) at baseline, before TAVI (n = 48) were randomized to aspirin + clopidogrel or aspirin + ticagrelor for 3 months, whereas those with normal PR (NPR) (n = 20) were continued on aspirin + clopidogrel. A "raiser response" in PR was defined as an increase in PR units >20% of baseline after TAVI. Patients with HPR before TAVI presented concomitant anemia and chronic kidney disease more frequently than their counterparts with NPR. Anemia and higher body mass index were independently associated with HPR to clopidogrel at baseline. Moreover, anemic patients with baseline HPR who were continued on clopidogrel presented higher PR after TAVI than patients with HPR switched to ticagrelor. All patients with baseline NPR presented a "raiser response" after TAVI, which was nonexistent among patients with HPR managed with ticagrelor. In summary, anemia seems as a relevant factor associated with baseline HPR and higher PR after TAVI in patients with baseline HPR randomized to clopidogrel, whereas ticagrelor proved more effective than clopidogrel at attaining sustained reductions in PR during follow-up, regardless of baseline comorbidities.

Aspirin Versus Dual Antiplatelet Therapy in Patients Undergoing Trans-Catheter Aortic Valve Implantation, Updated Meta-Analysis

BACKGROUND

The Antiplatelet Therapy for Patients Undergoing Transcatheter Aortic-Valve Implantation (POPular TAVI) trial reported comparable composite endpoints of ischemic events using aspirin compared to dual antiplatelet therapy (DAPT). However, this trial was not powered to detect individual differences in ischemic events. We sought to conduct a meta-analysis to compare aspirin to DAPT on ischemic and bleeding events following TAVI.

METHODS

The MEDLINE database was searched from inception until September 2020 and only randomized clinical trials of patients receiving antiplatelet therapy following TAVI were included. The treatment effect was reported as rate ratios (RRs) with 95% confidence intervals.

RESULTS

Four randomized clinical trials of 1086 TAVI patients were included. There was a 51% reduction in major or life-threatening bleeding with aspirin compared with DAPT [RR 0.49, (95%CI 0.31 to 0.78)]. Aspirin was not associated with an increased risk of death [RR 1.01, (95%CI 0.62 to 1.65)], cardiovascular death [RR 1.15, (95%CI 0.56 to 2.36)], ischemic stroke [RR 0.93, (95%CI 0.51 to 1.70)], or MI [RR 0.53, (95%CI 0.18 to 1.57)].

CONCLUSIONS

This meta-analysis supports the use of aspirin as the optimal antiplatelet strategy following TAVI procedures in reducing bleeding without an increase in ischemic events compared with dual antiplatelet therapy.

Risks and benefits of concurrent treatment with antiplatelet and anticoagulation therapy in post-op bioprosthetic aortic valve replacement patients

BACKGROUND AND AIM

Among patients receiving surgical bioprosthetic aortic valve replacement (bAVR), there is an elevated risk of thromboembolic events postoperatively. However, the risks and benefits of varying anticoagulation strategies remain controversial. The aim of this study is to compare the risks and benefits of aspirin monotherapy to aspirin plus warfarin ("concurrent therapy") in patients receiving bAVR.

METHODS

A retrospective cohort study was conducted using patients' data from Kaiser Permanente Northern California, including those who underwent bAVR with or without coronary artery bypass grafting between 2009 and 2018. Patients were identified as having been discharged with aspirin only or concurrent therapy. The outcomes were mortality, thromboembolic events, and clinically relevant bleeding during a 6-month follow-up. The event rates were compared using the Kaplan-Meier method. Multivariable survival analysis, incorporating propensity scores, was used to estimate adjusted hazard ratios (aHRs) for each outcome.

RESULTS

The cohort consisted of 3047 patients. Approximately 58% of patients received aspirin only and 42% received concurrent therapy. Patients who received concurrent therapy were more likely to be older, have hypertension, previous stroke, and longer hospital stays. After adjustment using multivariable analysis, concurrent therapy was associated with a higher risk of clinically relevant bleeding (aHR, 2.33; 95% confidence interval, 1.67-3.25). There was no significant difference in the risk of thromboembolic events or mortality between the two groups.

CONCLUSION

Patients who underwent bAVR and were discharged on concurrent therapy compared to aspirin only had a significantly increased risk of bleeding without a significant difference in thromboembolic events.

Antithrombotic selection in patients undergoing transcatheter aortic valve replacement

PURPOSE

Clinical controversy regarding the most appropriate antithrombotic regimen after transcatheter aortic valve replacement remains. Current evidence, guidelines, and recommendations are discussed.

SUMMARY

Antithrombotic selection following transcatheter aortic valve replacement depends on a variety of patient-specific factors. For patients without a preexisting indication for anticoagulation, initial trials employed dual antiplatelet therapy as the postprocedural therapy of choice. Newer studies in this patient population, however, suggest single antiplatelet therapy reduces bleeding events without sacrificing ischemic protection. In patients with a preexisting indication for anticoagulation, warfarin plus single antiplatelet therapy, as opposed to triple antithrombotic therapy, offered similar ischemic protection while reducing clinically significant bleeding. Warfarin monotherapy was associated with a further reduction in bleeding events. One trial demonstrated the safety and efficacy of using apixaban in patients with concomitant atrial fibrillation; however, routine use of rivaroxaban increased adverse cardiac and bleeding events, leaving the utility of direct-acting oral anticoagulants in question.

CONCLUSION

Available evidence and current guidelines point to a lack of consensus regarding antithrombotic selection after transcatheter aortic valve replacement. Patient-specific factors and comorbidities must be considered when tailoring therapy, with an emphasis on balancing thrombotic and bleeding risks.

Antithrombotic therapy with or without clopidogrel after transcatheter aortic valve replacement. A meta-analysis of randomized controlled trials

AIMS

To investigate the clinical outcomes associated with an antithrombotic therapy with or without clopidogrel after transcatheter aortic valve replacement (TAVR).

METHODS AND RESULTS

This is a study-level meta-analysis including all randomized trials investigating antithrombotic regimens after TAVR. The protocol was registered with PROSPERO (CRD42020191036). We searched electronic scientific databases for eligible studies. The primary outcome was all-cause death. Main secondary outcome was major bleeding. Other outcomes were life-threatening (or disabling) bleeding, myocardial infarction (MI) and stroke. Six eligible trials randomly allocated 3056 TAVR patients to aspirin or oral anticoagulation (OAC) with clopidogrel (n = 1525) versus aspirin and/or OAC without clopidogrel (n = 1531). In the overall estimates, an antithrombotic therapy with clopidogrel versus without displayed a comparable risk of all-cause death [Risk Ratio-RR = 0.83, 95% Confidence intervals-CI (0.57-1.20); P = 0.25] and major bleeding [RR = 1.33, 95% CI (0.61-2.92); P = 0.39]. However, the combination of aspirin or OAC with clopidogrel doubled the risk of major bleeding as compared to aspirin or OAC without clopidogrel [RR = 2.08, 95% CI (1.27-3.42); P = 0.015, P for interaction = 0.021]. Treatment strategies did not differ with respect to the risk of life-threatening bleeding, MI and stroke.

CONCLUSIONS

In patients receiving TAVR, a therapeutic strategy of aspirin or OAC with clopidogrel significantly increases the risk of major bleeding without impact on mortality and ischemic outcomes compared to aspirin or OAC without clopidogrel. The performance of different antithrombotic regimens in terms of long-term clinical outcomes and bioprosthesis valve function requires further investigation. Forest plots from pairwise and network meta-analyses associated with an antithrombotic therapy with or without clopidogrel Risk ratio for all outcomes of interest calculated with the pairwise meta-analysis (left side) and for main outcomes calculated with the network meta-analysis (right side) in patients allocated to an antithrombotic therapy with clopidogrel or without. The diamonds indicate the point estimate and the left and the right ends of the lines the [95% CI]. CI: Confidence intervals; OAC; oral anticoagulation.

Bleeding Complications Drive In-Hospital Mortality of Patients with Atrial Fibrillation after Transcatheter Aortic Valve Replacement

Background Atrial fibrillation (AF) is a risk factor for poor postoperative outcome after transfemoral transcatheter aortic valve replacement (TF-TAVR). The present study analyses the outcomes after TF-TAVR in patients with or without AF and identifies independent predictors for in-hospital mortality in clinical practice.

Methods and Results Among all 57,050 patients undergoing isolated TF-TAVR between 2008 and 2016 in Germany, 44.2% of patients (n = 25,309) had AF. Patients with AF were at higher risk for unfavorable in-hospital outcome after TAVR. Including all baseline characteristics for a risk-adjusted comparison, AF was an independent risk factor for in-hospital mortality after TAVR. Among patients with AF, EuroSCORE, New York Heart Association classification class, or renal disease had only moderate effects on mortality, while the occurrence of postprocedural stroke or moderate to major bleeding substantially increased in-hospital mortality (odds ratio [OR] 3.35, 95% confidence interval [CI] 2.61–4.30, p < 0.001 and OR 3.12, 95% CI 2.68–3.62, p < 0.001). However, the strongest independent predictor for in-hospital mortality among patients with AF was severe bleeding (OR 18.00, 95% CI 15.22–21.30, p < 0.001).

Conclusion The present study demonstrates that the incidence of bleeding defines the in-hospital outcome of patients with AF after TF-TAVR. Thus, the periprocedural phase demands particular care in bleeding prevention.

Surgical vs transfemoral aortic valve replacement in low-risk patients: An updated meta-analysis of trial and registry data

BACKGROUND

Transfemoral aortic valve replacement (TAVR) has been studied extensively in patients with improving safety and efficacy in high to intermediate-risk patients with aortic stenosis. TAVR has been now approved for patients with low surgical risk.

OBJECTIVE

The purpose of this study is to integrate the evidence from randomized controlled trials (RCT) and large registry data comparing TAVR to surgical aortic valve repair (SAVR).

METHODS

Seven studies (three RCTs, one post hoc study of a RCT, and three registries) were included. Incidence rate ratios (IRR) of outcomes of interest (overall mortality, 30-day mortality, cardiovascular death, stroke, pacemaker implantation [PPMI], myocardial infarction, moderate-severe paravalvular leak [PVL], and re-intervention) were compared using a random-effects model.

RESULTS

The pooled analysis included 24 819 patients (TAVR, 8227 and SAVR, 16 592). 2,952 (11.9%) patients were from RCTs and 21 867 (88.1%) were registry patients. Thirty-day mortality was lower in TAVR (logIRR, -0.43; 95% CI. -0.61 to -0.25; P < .001), whereas the rate of moderate-severe PVL (logIRR, 1.44; 95% CI, 0.58-2.3; P < .001) and PPMI (logIRR, 1.13; 95% CI, 1.02-1.24; P < .001) were higher. There were no significant differences in the rates of overall mortality, reintervention, cardiovascular death, myocardial infarction, or stroke between SAVR and TAVR.

CONCLUSIONS

Early mortality is higher in SAVR while rates of PVL and PPMI are substantially higher in TAVR. There is no significant advantage with TAVR for overall survival, cardiovascular death, stroke, MI, and re-intervention rates.

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.

Leaflet thickening and stent geometry in sutureless bioprosthetic aortic valves

Underexpansion of transcatheter heart valves and the surgically implanted Perceval sutureless aortic valve bioprosthesis has been suggested as an underlying mechanism for hypo-attenuated leaflet thickening (HALT). This was a single-center prospective observational study that included 47 patients who underwent surgical aortic valve replacement with the Perceval sutureless bioprosthesis (LivaNova, London, United Kingdom) from 2012 to 2016 and were studied by four-dimensional cardiac computed tomography (CT). The association between overall and regional expansion and the prevalence of HALT was analyzed. In total 46 patients were included in the analysis. HALT was found in 39.1% of patients and the mean overall prosthesis expansion was 75.5 ± 5.2% (range 64.6–84.8%). Overall expansion did not differ between patients with HALT compared with patients without HALT (mean overall expansion 74.0 ± 5.2% vs. 76.5 ± 5.0%, P = 0.11). The prevalence of HALT was lower in patients with overall expansion > 80% compared to patients with expansion < 80% expansion though not significantly (20% vs. 44.4%, P = 0.16). None or trivial regional underexpansion was found in 94.7% of coronary cusps. There was no significant association between regional underexpansion and the prevalence of HALT (mean coronary cusp angle 120 ± 8° vs. 119 ± 10°, P = 0.53). The prevalence of HALT and overall underexpansion was high in the Perceval sutureless bioprosthetic valve. Overall underexpansion was not associated with HALT. Whether severe overall underexpansion increases the risk for HALT requires further study. Regional underexpansion was uncommon in the Perceval sutureless bioprosthetic valve and not associated with HALT.

Clinical trial registration Unique identifier: NCT03753126 (http://www.clinicaltrials.gov).

[What antithrombotic treatment should we prescribe after transvalvular aortic valve implantation?]

The performance and indications of transvalvular aortic valve implantation or TAVI has considerably expanded and is now the first therapeutic line option in the management of severe aortic stenosis. The targeted population shares both high risk of ischemic complications, particularly stroke or subclinical leaflet thrombosis of the bioprothesis, as well as hemorrhagic complications, strongly correlated to death. Based on previous experience with intracoronary stents, a dual antiplatelet therapy has been recommended by experts' consensus. This paradigm is now challenged by the observed increased risk of hemorrhagic complications without a reduction of ischemic events. Moreover, the role of non-vitamin K oral anticoagulant in patients undergoing TAVI remains to be determined. Several large ongoing randomized controlled trials will likely change our practice within the next coming year.

Adjunct Pharmacotherapy After Transcatheter Aortic Valve Replacement: Current Status and Future Directions

Transcatheter aortic valve replacement (TAVR) is a validated treatment option for severe aortic stenosis. Ischemic and thrombotic complications remain important and strongly correlate with mortality. The optimal postprocedural antithrombotic strategy for prevention of thrombotic events remains unclear. The international guidelines for medical management following TAVR are discordant, allowing for significant variance in prescribing habits. The optimal treatment strategy has yet to be delineated. Clinical trials are ongoing to assess the risks and benefits of various strategies. We discuss the pathobiology and rationale for antithrombotic therapy after TAVR, review current evidence and guidelines, and offer a concise evidence-based approach to this subject.

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.