Natural History of Leaflet Thrombosis After Transcatheter Aortic Valve Replacement: A 5-Year Follow-Up Study

Prediction of hypoattenuating leaflet thickening in patients undergoing transcatheter aortic valves replacement based on clinical factors and 4D-computed tomography morphological characteristics: A retrospective cross-sectional study

BACKGROUND

The rapid increase in the number of transcatheter aortic valve replacement (TAVR) procedures in China and worldwide has led to growing attention to hypoattenuating leaflet thickening (HALT) detected during follow-up by 4D-CT. It's reported that HALT may impact the durability of prosthetic valve. Early identification of these patients and timely deployment of anticoagulant therapy are therefore particularly important.

METHODS

We retrospectively recruited 234 consecutive patients who underwent TAVR procedure in Fuwai Hospital. We collected clinical information and extracted morphological characteristics parameters of the transcatheter heart valve (THV) post TAVR procedure from 4D-CT. LASSO analysis was conducted to select important features. Three models were constructed, encapsulating clinical factors (Model 1), morphological characteristics parameters (Model 2), and all together (Model 3), to identify patients with HALT. Receiver operating characteristic (ROC) curves and decision curve analysis (DCA) were plotted to evaluate the discriminatory ability of models. A nomogram for HALT was developed and verified by bootstrap resampling.

RESULTS

In our study patients, Model 3 (AUC = 0.738) showed higher recognition effectiveness compared to Model 1 (AUC = 0.674, p = 0.032) and Model 2 (AUC = 0.675, p = 0.021). Internal bootstrap validation also showed that Model 3 had a statistical power similar to that of the initial stepwise model (AUC = 0.723 95%CI: 0.661-0.786). Overall, Model 3 was rated best for the identification of HALT in TAVR patients.

CONCLUSION

A comprehensive predictive model combining patient clinical factors with CT-based morphology parameters has superior efficacy in predicting the occurrence of HALT in TAVR patients.

Hypoattenuated Leaflet Thickening: A Comprehensive Review of Contemporary Data

Nearly one-third of patients who undergo surgical aortic valve replacement (SAVR) or transcatheter aortic valve replacement (TAVR) develop hypoattenuated leaflet thickening (HALT) within a year. HALT typically represents subclinical leaflet thrombosis in asymptomatic patients, and as a result it often is detected incidentally. However, HALT also may worsen in severity, resulting in leaflet immobility and/or valve deterioration. The clinical significance of HALT is a topic of ongoing debate, and currently there is no consensus on the screening and management of HALT in patients following TAVR or SAVR. This review provides a comprehensive evaluation of the available evidence on risk factors, preventative measures, treatment, and prognosis for this growing patient cohort.

Bioprosthetic Aortic Valve Thrombosis: Definitions, Clinical Impact, and Management: A State-of-the-Art Review

Bioprosthetic aortic valve thrombosis is frequently detected after transcatheter and surgical aortic valve replacement due to advances in cardiac computed tomography angiography technology and standardized surveillance protocols in low-surgical-risk transcatheter aortic valve replacement trials. However, evidence is limited concerning whether subclinical leaflet thrombosis leads to clinical adverse events or premature structural valve deterioration. Furthermore, there may be net harm in the form of bleeding from aggressive antithrombotic treatment in patients with subclinical leaflet thrombosis. This review will discuss the incidence, mechanisms, diagnosis, and optimal management of bioprosthetic aortic valve thrombosis after transcatheter aortic valve replacement and bioprosthetic surgical aortic valve replacement.

Surgical versus transcatheter aortic valve replacement in low-risk Medicare beneficiaries

OBJECTIVE

Recent approval of transcatheter aortic valve replacement (TAVR) in patients at low surgical risk has resulted in a rapid real-world expansion of TAVR in patients not otherwise examined in recent low-risk trials. We sought to evaluate the outcomes of surgical aortic valve replacement (SAVR) versus TAVR in low-risk Medicare beneficiaries.

METHODS

Using the US Centers for Medicare and Medicaid Services claims database, we evaluated all beneficiaries undergoing isolated SAVR (n = 33,210) or TAVR (n = 77,885) (2018-2020). International Classification of Diseases 10th revision codes were used to define variables and frailty was defined by the validated Kim index. Doubly robust risk adjustment was performed with inverse probability weighting and multilevel regression models, as well as competing-risk time to event analysis. A low-risk cohort was identified to simulate recent low-risk trials.

RESULTS

A total of 15,749 low-risk patients (8144 SAVR and 7605 TAVR) were identified. Comparison was performed with doubly robust risk adjustment accounting for all factors. TAVR was associated with lower perioperative stroke (odds ratio, 0.62; P < .001) and hospital mortality (odds ratio, 0.16; P < .001) compared with SAVR. However, risk-adjusted longitudinal analysis demonstrated TAVR was associated with higher late risk of stroke (hazard ratio, 1.65; P < .001), readmission for valve reintervention (hazard ratio, 1.88; P < .001), and all-cause mortality (hazard ratio, 1.54; P < .001) compared with SAVR.

CONCLUSIONS

Among low-risk Medicare beneficiaries younger than age 75 years undergoing isolated AVR, SAVR was associated with higher index morbidity and mortality but improved 3-year risk-adjusted stroke, valve reintervention, and survival compared with TAVR.

What is the current optimal antithrombotic therapy after transcatheter aortic valve implantation? Current evidence from Japan and the world

Aortic stenosis (AS) is a major valvular disease that can have a negative impact on patients' prognosis, and its prevalence is increasing due to an aging population worldwide. Transcatheter aortic valve implantation (TAVI) is a well-established therapy for symptomatic severe AS utilized across the entire surgical risk spectrum. Based on the recently published evidence of large, randomized controlled trials (RCTs), the number of patients undergoing TAVI is increasing worldwide. Ischemic and bleeding events are common after TAVI and can have serious consequences both immediately after the procedure and in the long-term. Antiplatelet therapy has been traditionally recommended to prevent thromboembolic events after TAVI. The situation regarding the optimal antithrombotic regimen following TAVI is rapidly changing because many game-changing RCTs have been published. This report provides an overview of the current status and remaining issues in the field of optimal antithrombotic therapy following TAVI, including its possible effect on leaflet thrombosis.

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.

Leaflet thrombosis in transcatheter aortic valve intervention: mechanisms, prevention, and treatment options

Introduction

Transcatheter aortic valve intervention (TAVR) has emerged as a promising alternative to surgical aortic valve replacement for patients with severe aortic stenosis. However, leaflet thrombosis has raised concerns about the long-term durability and outcomes of TAVR. This study aims to provide an overview of the mechanisms, prevention strategies, and treatment options for leaflet thrombosis in TAVR.

Clinical evidence

Leaflet thrombosis refers to the formation of blood clots on bioprosthetic valve leaflets, leading to impaired leaflet mobility, early valve degeneration and dysfunction, and potential clinical implications. While the mechanisms underlying thrombus formation on valve leaflets are not fully understood, several factors, such as altered blood flow patterns within valve neosinuses, prothrombotic surfaces, and patient-related causes, have been implicated. Two distinct entities have been identified, namely, hypoattenuated leaflet thickening and restricted leaflet motion. Their occurrence appears dynamic over time and is related to the valve type. Imaging, including transesophageal echocardiography and multidetector computed tomography, plays a crucial role in the diagnosis and follow-up of leaflet thrombosis.

Prevention and treatment options

Preventing leaflet thrombosis requires a comprehensive and tailored approach involving identifying high-risk patients, close monitoring, and antithrombotic therapy. Antithrombotic therapy with dual antiplatelet agents or anticoagulation is commonly employed in TAVR patients, although the optimal regimen is yet to be defined. Novel antithrombotic agents, such as direct oral anticoagulants, are being investigated for their efficacy and safety in preventing leaflet thrombosis. When leaflet thrombosis is detected, treatment options include intensified antithrombotic therapy, valve-in-valve intervention, or balloon valvuloplasty. The long-term outcomes and impact of leaflet thrombosis on valve durability and patient prognosis are areas of ongoing research.

Summary

Leaflet thrombosis in TAVR is a considerable complication affecting valve function and patient outcomes. Understanding the mechanisms underlying thrombus formation and implementing appropriate prevention strategies are essential for mitigating this risk. Treatment options aim to restore leaflet mobility and optimize valve performance. Further research is needed to establish standardized protocols for antithrombotic therapy, identify high-risk patient populations, and determine the long-term consequences of leaflet thrombosis on TAVR outcomes.

Hyperacute Sapien Aortic Valve thrombosis in a patient with Antiphospholipid Syndrome (APS)

In this case we briefly describe the case of an old woman presenting with acute exertional dyspnea due to hyperacute Sapien Valve thrombosis.

Advanced Cardiac Imaging in the Assessment of Aortic Stenosis

Aortic stenosis is the most common form of valve disease in the Western world and a major healthcare burden. Although echocardiography remains the central modality for the diagnosis and assessment of aortic stenosis, recently, advanced cardiac imaging with cardiovascular magnetic resonance, computed tomography, and positron emission tomography have provided invaluable pathological insights that may guide the personalized management of the disease. In this review, we discuss applications of these novel non-invasive imaging modalities for establishing the diagnosis, monitoring disease progression, and eventually planning the invasive treatment of aortic stenosis.

Mild Paravalvular Leak May Pose an Increased Thrombogenic Risk in Transcatheter Aortic Valve Replacement (TAVR) Patients-Insights from Patient Specific In Vitro and In Silico Studies

In recent years, the treatment of aortic stenosis with TAVR has rapidly expanded to younger and lower-risk patients. However, persistent thrombotic events such as stroke and valve thrombosis expose recipients to severe clinical complications that hamper TAVR's rapid advance. We presented a novel methodology for establishing a link between commonly acceptable mild paravalvular leak (PVL) levels through the device and increased thrombogenic risk. It utilizes in vitro patient-specific TAVR 3D-printed replicas evaluated for hydrodynamic performance. High-resolution µCT scans are used to reconstruct in silico FSI models of these replicas, in which multiple platelet trajectories are studied through the PVL channels to quantify thrombogenicity, showing that those are highly dependent on patient-specific flow conditions within the PVL channels. It demonstrates that platelets have the potential to enter the PVL channels multiple times over successive cardiac cycles, increasing the thrombogenic risk. This cannot be reliably approximated by standard hemodynamic parameters. It highlights the shortcomings of subjectively ranked PVL commonly used in clinical practice by indicating an increased thrombogenic risk in patient cases otherwise classified as mild PVL. It reiterates the need for more rigorous clinical evaluation for properly diagnosing thrombogenic risk in TAVR patients.