Medical Treatment of Aortic Stenosis

Unmet needs and knowledge gaps in aortic stenosis: A position paper from the Heart Valve Council of the French Society of Cardiology

Nowadays, valvular heart disease remains a significant challenge among cardiovascular diseases, affecting millions of people worldwide and exerting substantial pressure on healthcare systems. Within the spectrum of valvular heart disease, aortic stenosis is the most common valvular lesion in developed countries. Despite notable advances in understanding its pathophysiological processes, improved cardiovascular imaging techniques and expanding therapeutic options in recent years, there are still unmet needs and knowledge gaps regarding aortic stenosis pathophysiology, severity assessment, management and decision-making strategy. This review, prepared on behalf of the Heart Valve Council of the French Society of Cardiology, describes these gaps and future research perspectives to improve the outcome of patients with aortic stenosis.

Genetic causal association between lipidomic profiles, inflammatory proteomics, and aortic stenosis: a Mendelian randomization investigation

BACKGROUND

Aortic stenosis (AS) is a prevalent and serious valvular heart disease with a complex etiology involving genetic predispositions, lipid dysregulation, and inflammation. The specific roles of lipid and protein biomarkers in AS development are not fully elucidated. This study aimed to elucidate the causal relationships between lipidome, inflammatory proteins, and AS using Mendelian randomization (MR), identifying potential therapeutic targets.

METHODS

Utilizing data from large-scale genome-wide association studies (GWAS) and genome-wide protein quantitative trait loci (pQTL) studies, we conducted MR analyses on 179 plasma lipidome and 91 inflammatory proteins to assess their causal associations with AS. Our approach included Inverse Variance Weighting (IVW), Wald ratio, and robust adjusted profile score (RAPS) analyses to refine these associations. MR-Egger regression was used to address directional horizontal pleiotropy.

RESULTS

Our MR analysis showed that genetically predicted 50 lipids were associated with AS, including 38 as risk factors [(9 Sterol ester, 18 Phosphatidylcholine, 4 Phosphatidylethanolamine, 1 Phosphatidylinositol and 6 Triacylglycerol)] and 12 as protective. Sterol ester (27:1/17:1) emerged as the most significant risk factor with an odds ratio (OR) of 3.11. Additionally, two inflammatory proteins, fibroblast growth factor 19 (FGF19) (OR = 0.830, P = 0.015), and interleukin 6 (IL-6) (OR = 0.729, P = 1.79E-04) were significantly associated with reduced AS risk. However, a two-step MR analysis showed no significant mediated correlations between these proteins and the lipid-AS pathway.

CONCLUSION

This study reveals complex lipid and protein interactions in AS, identifying potential molecular targets for therapy. These results go beyond traditional lipid profiling and significantly advance our genetic and molecular understanding of AS, highlighting potential pathways for intervention and prevention.

Robust automated calcification meshing for personalized cardiovascular biomechanics

Calcification has significant influence over cardiovascular diseases and interventions. Detailed characterization of calcification is thus desired for predictive modeling, but calcium deposits on cardiovascular structures are still often manually reconstructed for physics-driven simulations. This poses a major bottleneck for large-scale adoption of computational simulations for research or clinical use. To address this, we propose an end-to-end automated image-to-mesh algorithm that enables robust incorporation of patient-specific calcification onto a given cardiovascular tissue mesh. The algorithm provides a substantial speed-up from several hours of manual meshing to ~1 min of automated computation, and it solves an important problem that cannot be addressed with recent template-based meshing techniques. We validated our final calcified tissue meshes with extensive simulations, demonstrating our ability to accurately model patient-specific aortic stenosis and Transcatheter Aortic Valve Replacement. Our method may serve as an important tool for accelerating the development and usage of personalized cardiovascular biomechanics.

Recent updates on asymptomatic and symptomatic aortic valve stenosis its diagnosis, pathogenesis, management and future perspectives

Aortic stenosis (AS) is very common in mid-aged and elderly patients, and it has been reported to have a negative impact on both short and long-term survival with a high mortality rate. The current study identified methods of diagnosis, incidence, and causes of AS, pathogenesis, intervention and management and future perspectives of Asymptomatic and Symptomatic Aortic stenosis. A systematic literature search was conducted using PubMed, Scopus and CINAHL, using the Mesh terms and key words "Aortic stenosis", "diagnostic criteria", "pathogenesis", "incidence and causes of AS" and" intervention and management strategies". Studies were retained for review after meeting strict inclusion criteria that included studies evaluating Asymptomatic and Symptomatic AS. Studies were excluded if duplicate publication, overlap of patients, subgroup studies of a main study, lack of data on AS severity, case reports and letters to editors. Forty-five articles were selected for inclusion. Incidence of AS across the studies ranged from 3 % to 7 %. Many factors have been associated with incidence and increased risk of AS, highest incidence of AS was described after aortic valve calcification, rheumatic heart disease, degenerative aortic valve disease, bicuspid aortic valve and other factors. AS is common and can be predicted by aortic root calcification volume, rheumatic heart disease, degenerative aortic valve disease, bicuspid aortic valve. Intervention and management for AS patients is a complex decision that takes into consideration multiple factors. On the other hand, there is not enough progress in preventive pharmacotherapy to slow the progression of AS.

Prognostic Value of CT-Derived Myocardial Biomarkers: Extracellular Volume Fraction and Strain in Patients with Severe Aortic Stenosis Undergoing Transcatheter Aortic Valve Replacement: A Systematic Review and Meta-analysis

RATIONALE AND OBJECTIVES

This study aimed to investigate the prognostic value of preoperative CT scan-derived myocardial biomarkers in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR).

MATERIALS AND METHODS

In April 2024, three databases (PubMed, Web of Science and Embase) were searched to identify studies. A random-effects model for meta-analysis was conducted to calculate pooled hazard ratios (HR) and 95% confidence intervals (CI) to assess the prognostic value. The I2 statistic was used to assess heterogeneity. Meta-regression analysis was conducted to appraise which variables yielded a significant impact on the HR of included biomarkers.

RESULTS

11 studies were identified, of which six studies involved 678 patients reporting extracellular volume fraction (ECV), one study involved 300 patients reporting ECV and left ventricular global longitudinal strain (LVGLS), three studies involved 868 patients reporting LVGLS and one study involved 376 patients reporting LVGLS and peak left atrial longitudinal strain (PALS). The endpoints included all-cause mortality, major adverse cardiovascular events (MACE) and a composite outcome of the previous two. The meta-analysis revealed that ECV, whether considered as a dichotomous variable (pooled HR: 3.87, 95% CI: 2.63-5.70, I2 = 0%), or as a continuous variable (pooled HR: 1.12, 95% CI: 1.05-1.19, I2 = 66%), and LVGLS, whether considered as a dichotomous variable (pooled HR: 1.70, 95% CI: 1.30-2.22, I2 = 0%) or a continuous variable (pooled HR: 1.07, 95% CI: 1.04-1.10, I2 = 0%) were all significant predictors for outcomes in patients with severe AS after TAVR. Age, sex, follow-up time and mean pressure gradient had a significant impact on the model of ECV (continuous).

CONCLUSION

The higher CT-derived ECV and impaired LVGLS are able to predict worse outcomes in patients with severe AS who have undergone TAVR.

Impact of Neighborhood Social Deprivation on Delays to Access for Transcatheter Aortic Valve Replacement: Wait-Times and Clinical Consequences

BACKGROUND

Transcatheter aortic valve replacement (TAVR) has become the standard of care for severe aortic stenosis treatment. Exponential growth in demand has led to prolonged wait times and adverse patient outcomes. Social marginalization may contribute to adverse outcomes. Our objective was to examine the association between different measures of neighborhood-level marginalization and patient outcomes while on the TAVR waiting list. A secondary objective was to understand if sex modifies this relationship.

METHODS AND RESULTS

We conducted a population-based retrospective cohort study of 11 077 patients in Ontario, Canada, referred to TAVR from April 1, 2018, to March 31, 2022. Primary outcomes were death or hospitalization while on the TAVR wait-list. Using cause-specific Cox proportional hazards models, we evaluated the relationship between neighborhood-level measures of dependency, residential instability, material deprivation, and ethnic and racial concentration with primary outcomes as well as the interaction with sex. After multivariable adjustment, we found a significant relationship between individuals living in the most ethnically and racially concentrated areas (quintile 4 and 5) and mortality (hazard ratio [HR], 0.64 [95% CI, 0.47-0.88] and HR, 0.73 [95% CI, 0.53-1.00], respectively). There was no significant association between material deprivation, dependency, or residential instability with mortality. Women in the highest ethnic or racial concentration quintiles (4 and 5) had significantly lower risks for mortality (HR values of 0.52 and 0.56, respectively) compared with quintile 1.

CONCLUSIONS

Higher neighborhood ethnic or racial concentration was associated with decreased risk for mortality, particular for women on the TAVR waiting list. Further research is needed to understand the drivers of this relationship.

Transcatheter aortic valve implantation in severe aortic stenosis does not necessarily reverse left ventricular myocardial damage: data of long-term follow-up

AIMS

Aortic stenosis (AS) is causing myocardial damage and replacement is mainly indicated based on symptoms. Non-invasive estimation of myocardial work (MW) provides a less afterload-dependent too for assessing myocardial function. We sought to look at the impact of transcatheter aortic valve implantation (TAVI) on the myocardium at long-term follow-up and according to current indications.

METHODS AND RESULTS

We conducted an observational, cross-sectional, single-centre study. Patients were selected based on the validated indication for a TAVI. Standardized echocardiographies were repeated. A total of 102 patients were included. The mean age was 85 years, 45% were female, 68% had high blood pressure, and 52% had a coronary disease. One-fifth was suffering from low-flow-low-gradient AS. A follow-up was performed at 22 ± 9.5 months after the TAVI. No TAVI dysfunction was observed. Left ventricular (LV) ejection fraction was stable (62 ± 8%), and global longitudinal strain had improved (-14.0 ± 3.7 vs. -16.0 ± 3.6%, P < 0.0001). No improvement of the MW parameters was noticed (LV global work index 2099 ± 692 vs. 2066 ± 706 mmHg%, P = 0.8, LV global constructive 2463 ± 736 vs. 2463 ± 676 mmHg%, P = 0.8). Global wasted work increased [214 (149; 357) vs. 247 (177; 394) mmHg%, P = 0.0008].

CONCLUSION

In a population of severe symptomatic AS patients who had undergone a TAVI, the non-invasive myocardial indices that assess the LV performance at long-term follow-up did not improve. These results are questioning the timing of the intervention and the need for more attention in the pharmacological management of these AS patients.

Diastolic Dysfunction and Atrial Fibrillation: Recognition, Interplay, and Management

Diastolic dysfunction occurs when the left ventricle loses its ability to relax normally, impairing ventricular filling during diastole. This most commonly occurs as a pathological sequela of left ventricular hypertrophy and remodeling due to chronic hypertension and/or age-related sclerotic changes of the aortic valve. This can subsequently deteriorate to diastolic heart failure or heart failure with preserved ejection fraction. There is a substantive interplay between atrial fibrillation and diastolic dysfunction, as atrial fibrillation can cause, exacerbate, or be a direct result of diastolic dysfunction and vice versa. In this review, we first independently define diastolic heart failure and atrial fibrillation while discussing the diagnostic guidelines, which encompass various modalities such as medical history, electrocardiography, echocardiography, and laboratory tests. We subsequently examine their interplay and pathophysiological links drawing on recent evidence in the literature. Finally, we discuss management approaches, including pharmacological interventions targeting rate and rhythm control, diuretics, and addressing comorbidities.

Female showed favorable left ventricle hypertrophy regression during post-TAVR follow-up

Transcatheter aortic valve replacement (TAVR) is a well-established procedure using a catheter-introduced valve prosthesis for patients with severe aortic stenosis (AS). This retrospective study investigated sex-related differences in pre- and post-TAVR clinical and hemodynamic outcomes and analyzed data of the first 100 cases at Kaohsiung Medical University Chung-Ho Memorial Hospital (KMUH) between December 2013 and December 2021. Baseline characteristics, procedural outcomes, mortality rates, and echocardiographic parameters were analyzed and compared between sexes. Among the 100 patients, male (46%) and female (54%) were of similar age (mean age, male 86.0 years vs. female 84.5 years) and of the same severity of AS (mean pressure gradient, male 47.5 mmHg vs. female 45.7 mmHg) at the time receiving the TAVR procedure. Women had smaller aortic valve areas calculated by continuity equation (0.8 ± 0.3 cm2 vs. 0.7 ± 0.2 cm2, p < 0.001). In addition, women had better left ventricle ejection fraction (59.6 ± 14.0% vs. men 54.7 ± 17.2%, p < 0.01). In the post-TAVR follow-up, regression of left ventricle mass and dimension was better in women than in men. None of the patient died within 30 days after the procedure, and women tended to have a more favorable survival than men (2-year mortality and overall mortality rate in 8.3 year, women 9.1% and 22.2% vs. men 22.2% and 34.8%; p = 0.6385 and 0.1277, respectively). In conclusion, the sex-based difference in post-TAVR regression of LV remodeling suggests a need for sex-based evaluation for patients with severe AS and their post TAVR follow-up.

Stress echocardiography in valvular heart disease

Valvular heart disease (VHD) has been a significant health problem, particularly in developed countries, in relation to the aging population. Recent developments in the management of VHD require a more accurate assessment of disease severity to determine the need for transcatheter interventions or open heart surgery. Stress echocardiography is a crucial imaging modality for identifying the underlying pathology of VHD. Optimal administration of exercise or intravenous drugs may reveal hemodynamic abnormalities under stress without posing an invasive risk. Therefore, the implementation of stress echocardiography is recommended for determining interventional indications and risk stratification in mitral regurgitation and aortic stenosis. In addition, recent evidence has accumulated regarding the usefulness of stress echocardiography in various conditions including mitral stenosis, aortic regurgitation, and post-interventional VHD. Here, we summarize the current evidence and future perspectives on stress echocardiography in VHD.

Perioperative and Anesthetic Considerations in Pediatric Valvar and Subvalvar Aortic Stenosis

Aortic stenosis (AS) is a common form of left ventricular outflow tract obstruction (LVOTO) in children with congenital heart disease. This review specifically considers the perioperative features of valvar (VAS) and subvalvar AS (subAS) in the pediatric patient. Although VAS and subAS share some clinical features and diagnostic approaches, they are distinct clinical entities with separate therapeutic options, which range from transcatheter intervention to surgical repair. We detail the pathophysiology of AS and highlight the range of treatment strategies with a focus on anesthetic considerations for the care of these patients before, during, and after intervention.

Inflammation-associated ectopic mineralization

Ectopic mineralization refers to the deposition of mineralized complexes in the extracellular matrix of soft tissues. Calcific aortic valve disease, vascular calcification, gallstones, kidney stones, and abnormal mineralization in arthritis are common examples of ectopic mineralization. They are debilitating diseases and exhibit excess mortality, disability, and morbidity, which impose on patients with limited social or financial resources. Recent recognition that inflammation plays an important role in ectopic mineralization has attracted the attention of scientists from different research fields. In the present review, we summarize the origin of inflammation in ectopic mineralization and different channels whereby inflammation drives the initiation and progression of ectopic mineralization. The current knowledge of inflammatory milieu in pathological mineralization is reviewed, including how immune cells, pro-inflammatory mediators, and osteogenic signaling pathways induce the osteogenic transition of connective tissue cells, providing nucleating sites and assembly of aberrant minerals. Advances in the understanding of the underlying mechanisms involved in inflammatory-mediated ectopic mineralization enable novel strategies to be developed that may lead to the resolution of these enervating conditions.

Increasing baseline aortic valve peak flow velocity is associated with progression of aortic valve stenosis in osteoporosis patients-a possible link to low vitamin D status

PURPOSE

The purpose of this study was to investigate the morphological characteristics of the aortic valve and identify factors associated with the progression of aortic valve stenosis (AS) in osteoporosis patients.

METHODS

In this single-center prospective cohort study, we recruited 10 patients (mean age: 75 ± 7 years, 90% female) who were taking anti-resorptive medicines at the outpatient clinic of University of Miyazaki Hospital, Japan. Baseline assessments, including transthoracic echocardiogram, blood sampling, and dual energy X-ray absorptiometry, were performed. Follow-up assessments were conducted at 6, 12, 18, and 24 months.

RESULTS

During the 2-year follow-up, three patients with aortic valve peak flow velocity (AV PFV) ≥2 m/s at baseline developed moderate AS, which is defined as AV PFV ≥3 m/s. However, seven patients with AV PFV <2 m/s did not exhibit any progression of AS. There were significant variations in terms of bone mineral density, T-score values, and biomarkers associated with bone turnover (i.e., bone alkaline phosphatase, tartrate-resistance acid phosphatase-5b) among the enrolled patients, but none of these factors were found to be associated with the progression of AS. All patients exhibited low vitamin D status, with a median level of 16.1 ng/mL (25th percentile, 9.7 ng/mL; 75th percentile, 23 ng/mL). The baseline levels of AV PFV values were negatively correlated with 25-hydroxyvitamin D levels, determined by univariate linear regression analysis (beta coefficient = -0.756, 95% confidence interval, -0.136 ̶ -0.023, p = 0.011).

CONCLUSION

Our data suggest that low vitamin D status might be a potential risk factor for the progression of AS in osteoporosis patients undergoing treatment with anti-resorptive medicines. Elderly patients with osteoporosis patients exhibited a subset of aortic valve stenosis. Our data suggest that the baseline aortic valve peak flow velocity predicts the progression of aortic valve stenosis, and there might be an association between the progression and the co-existing low vitamin D status in these patients.

Aortic Stenosis Phenotypes and Precision Transcatheter Aortic Valve Implantation

Patients with a clinical indication for aortic valve replacement can either undergo surgical aortic valve replacement (SAVR) or Transcatheter Aortic Valve Implantation (TAVI). There are many different factors that go into determining which type of replacement to undergo, including age, life expectancy, comorbidities, frailty, and patient preference. While both options offer significant benefits to patients in terms of clinical outcomes and quality of life, there is growing interest in expanding the indications for TAVI due to its minimally invasive approach. However, it is worth noting that there are several discrepancies in TAVI outcomes in regards to various endpoints, including death, stroke, and major cardiovascular events. It is unclear why these discrepancies exist, but potential explanations include the diversity of etiologies for aortic stenosis, complex patient comorbidities, and ongoing advancements in both medical therapies and devices. Of these possibilities, we propose that phenotypic variation of aortic stenosis has the most significant impact on post-TAVI clinical outcomes. Such variability in phenotypes is often due to a complex interplay between underlying comorbidities and environmental and inherent patient risk factors. However, there is growing evidence to suggest that patient genetics may also play a role in aortic stenosis pathology. As such, we propose that the selection and management of TAVI patients should emphasize a precision medicine approach.

A Systematic Review and Statistical Analysis of Factors Influencing the Cost-Effectiveness of Transcatheter Aortic Valve Implantation for Symptomatic Severe Aortic Stenosis

Objective

Transcatheter aortic valve implantation (TAVI) is a disruptive technology recommended for patients with symptomatic severe aortic stenosis (sSAS). Despite being available for over 15 years in Europe, with an extensive volume of clinical and economic evaluations across all surgical risk groups, there is little evidence on the identification of the key drivers of TAVI's cost-effectiveness. This study sought to identify these factors and quantify their role.

Methods

A systematic literature review was conducted to identify published economic evaluations of TAVI. This was supplemented by health technology assessment reports. The primary outcome was the likelihood of TAVI being found cost-effective. Secondary outcomes of TAVI being dominant, and the incremental health benefits of TAVI were also explored.

Results

Forty-two studies, reporting 65 unique analyses, were identified. TAVI was found to be cost-effective and dominant in 74% and 20% of analyses, respectively. The latest generation balloon-expandable TAVI device (SAPIEN 3) was more likely to be found cost-effective, as was TAVI use in low-risk populations and when performed via transfemoral access route. There was heterogeneity in the approach taken to economic modelling, which may also influence estimates of cost-effectiveness. Analyses that found TAVI to be dominant always compared it to surgery and usually considered the latest generation balloon-expandable TAVI device. Largest health benefits were observed for the inoperable risk group.

Conclusion

For patients with sSAS, TAVI is typically a cost-effective treatment option. There are important differences by device generation, risk group and access route. It is crucial to consider these differences when appraising the health economic evidence-base for TAVI.

The impact of moderate aortic stenosis in acute myocardial infarction: A multicenter retrospective study

BACKGROUND

Aortic stenosis (AS) is associated with myocardial ischemia through different mechanisms and may impair coronary arterial flow. However, data on the impact of moderate AS in patients with acute myocardial infarction (MI) is limited.

AIMS

This study aimed to investigate the impact of moderate AS in patients presenting with acute myocardial infarction (MI).

METHODS

We conducted a retrospective analysis of all patients who presented with acute MI to all Mayo Clinic hospitals, using the Enterprise Mayo PCI Database from 2005 to 2016. Patients were stratified into two groups: moderate AS and mild/no AS. The primary outcome was all cause mortality.

RESULTS

The moderate AS group included 183 (13.3%) patients, and the mild/no AS group included 1190 (86.7%) patients. During hospitalization, there was no difference between both groups in mortality. Patients with moderate AS had higher in-hospital congestive heart failure (CHF) (8.2% vs. 4.4%, p = 0.025) compared with mild/no AS patients. At 1-year follow-up, patients with moderate AS had higher mortality (23.9% vs. 8.1%, p < 0.001) and higher CHF hospitalization (8.3% vs. 3.7%, p = 0.028). In multivariate analysis, moderate AS was associated with higher mortality at 1-year (odds ratio 2.4, 95% confidence interval [1.4-4.1], p = 0.002). In subgroup analyses, moderate AS increased all-cause mortality in STEMI and NSTEMI patients.

CONCLUSION

The presence of moderate AS in acute MI patients was associated with worse clinical outcomes during hospitalization and at 1-year follow-up. These unfavorable outcomes highlight the need for a close follow-up of these patients and for timely therapeutic strategies to best manage these coexisting conditions.

The biological responses of vitamin K2: A comprehensive review

Vitamin K1 (VitK1) and Vitamin K2 (VitK2), two important naturally occurring micronutrients in the VitK family, found, respectively, in green leafy plants and algae (VitK1) and animal and fermented foods (VitK2). The present review explores the multiple biological functions of VitK2 from recently published in vitro and in vivo studies, including promotion of osteogenesis, prevention of calcification, relief of menopausal symptoms, enhancement of mitochondrial energy release, hepato- and neuro-protective effects, and possible use in treatment of coronavirus disease. The mechanisms of action associated with these biological effects are also explored. Overall, the findings presented here suggest that VitK, especially VitK2, is an important nutrient family for the normal functioning of human health. It acts on almost all major body systems and directly or indirectly participates in and regulates hundreds of physiological or pathological processes. However, as biological and clinical data are still inconsistent and conflicting, more in-depth investigations are warranted to elucidate its potential as a therapeutic strategy to prevent and treat a range of disease conditions.

Aortic Stenosis and Aortic Valve Replacement among Patients with Chronic Kidney Disease: A Narrative Review

BACKGROUND

Aortic stenosis (AS) can present with dyspnea, angina, syncope, and palpitations, and this presents a diagnostic challenge as chronic kidney disease (CKD) and other commonly found comorbid conditions may present similarly. While medical optimization is an important aspect in management, aortic valve replacement (AVR) by surgical aortic valve replacement (SAVR) or transcatheter aortic valve replacement (TAVR) is the definitive treatment. Patients with concomitant CKD and AS require special consideration as it is known that CKD is associated with progression of AS and poor long-term outcomes.

AIMS AND OBJECTIVES

The aim of the study was to summarize and review the current existing literature on patients with both CKD and AS regarding disease progression, dialysis methods, surgical intervention, and postoperative outcomes.

CONCLUSION

The incidence of AS increases with age but has also been independently associated with CKD and furthermore with hemodialysis (HD). Regular dialysis with HD versus peritoneal dialysis (PD) and female gender have been associated with progression of AS. Management of AS is multidisciplinary and requires planning and interventions by the heart-kidney team to decrease the risk of further inducing kidney injury among high-risk population. Both TAVR and SAVR are effective interventions for patients with severe symptomatic AS, but TAVR has been associated with better short-term renal and cardiovascular outcomes.

IMPLICATIONS FOR PRACTICE

Special consideration must be given to patients with both CKD and AS. The choice of whether to undergo HD versus PD among patients with CKD is multifactorial, but studies have shown benefit regarding AS progression among those who undergo PD. The choice regarding AVR approach is likewise the same. TAVR has been associated with decreased complications among CKD patients, but the decision is multifactorial and requires a comprehensive discussion with the heart-kidney team as many other factors play a role in the decision including preference, prognosis, and other risk factors.

Impact of nickel-titanium super-elastic material properties on the mechanical performance of self-expandable transcatheter aortic valves

Self-expandable transcatheter aortic valves (TAVs) elastically resume their initial shape when implanted without the need for balloon inflation by virtue of the nickel-titanium (NiTi) frame super-elastic properties. Experimental findings suggest that NiTi mechanical properties can vary markedly because of a strong dependence on the chemical composition and processing operations. In this context, this study presents a computational framework to investigate the impact of the NiTi super-elastic material properties on the TAV mechanical performance. Finite element (FE) analyses of TAV implantation were performed considering two different TAV frames and three idealized aortic root anatomies, evaluating the device mechanical response in terms of pullout force magnitude exerted by the TAV frame and peak maximum principal stress within the aortic root. The widely adopted NiTi constitute model by Auricchio and Taylor (1997) was used. A multi-parametric sensitivity analysis and a multi-objective optimization of the TAV mechanical performance were conducted in relation to the parameters of the NiTi constitutive model. The results highlighted that: five NiTi material model parameters (E_A, σ_tL^S, σ_tU^S, σ_tU^E and σ_cL^S) are significantly correlated with the FE outputs; the TAV frame geometry and aortic root anatomy have a marginal effect on the level of influence of each NiTi material parameter; NiTi alloy candidates with pareto-optimal characteristics in terms of TAV mechanical performance can be successfully identified. In conclusion, the proposed computational framework supports the TAV design phase, providing information on the relationship between the super-elastic behavior of the supplied NiTi alloys and the device mechanical response.

Association of renin-angiotensin system inhibitors use with short- and long-term mortality in patients with aortic stenosis: A systematic review and meta-analysis

Purpose

The present study aimed to investigate the association of renin-angiotensin system inhibitors (RASi) with short- and long-term mortality in patients with aortic stenosis (AS).

Methods

A systematic search was performed in PubMed, Embase, and Cochrane library databases for relevant studies published before March 2022. Studies meeting the inclusion criteria were included to assess the effect of RASi on short-term (≤30 days) and long-term (≥1 year) mortality in patients with AS.

Results

A total of 11 studies were included in the meta-analysis. Our results demonstrated that RASi reduced short-term mortality (OR = 0.76, 95% CI 0.63-0.93, p = 0.008) after aortic valve replacement (AVR). Subgroup analysis revealed that RASi was still associated with lower short-term mortality after transcatheter aortic valve replacement (TAVR); however, the association was relatively weak in patients who underwent surgical aortic valve replacement (SAVR). For long-term mortality, the pooled OR was 1.04 (95% CI 0.88-1.24, p = 0.63) after sensitivity analysis in patients who did not undergo AVR. In addition, our study confirmed that RASi significantly reduced long-term mortality (OR = 0.57, 95% CI 0.44-0.74, p < 0.0001) in patients who underwent AVR. Subgroup analysis showed that both TAVR and SAVR groups treated with RASi had lower long-term mortality.

Conclusion

Renin-angiotensin system inhibitors did not change long-term mortality in AS patients who did not undergo AVR. However, RASi reduced short- and long-term mortality in patients who underwent AVR.

An endogenous inhibitor of angiogenesis downregulated by hypoxia in human aortic valve stenosis promotes disease pathogenesis

Aortic valve stenosis is the most common valve disease in the western world. Central to the pathogenesis of this disease is the growth of new blood vessels (angiogenesis) within the aortic valve allowing infiltration of immune cells and development of intra-valve inflammation. Identifying the cellular mediators involved in this angiogenesis is important as this may reveal new therapeutic targets which could ultimately prevent the progression of aortic valve stenosis. Aortic valves from patients undergoing surgery for aortic valve replacement or dilation of the aortic arch were examined both ex vivo and in vitro. We now demonstrate that the anti-angiogenic protein, soluble fms-like tyrosine kinase 1 (sFlt1), a non-signalling soluble receptor for vascular endothelial growth factor, is constitutively expressed in non-diseased valves. sFlt-1 expression was, however, significantly reduced in aortic valve tissue from patients with aortic valve stenosis while protein markers of hypoxia were simultaneously increased. Exposure of primary-cultured valve interstitial cells to hypoxia resulted in a decrease in the expression of sFlt-1. We further reveal using a bioassay that siRNA knock-down of sFlt1 in valve interstitial cells directly results in a pro-angiogenic environment. Finally, incubation of aortic valves with sphingosine 1-phosphate, a bioactive lipid-mediator, increased sFlt-1 expression and inhibited angiogenesis within valve tissue. In conclusion, this study demonstrates that sFlt1 expression is directly correlated with angiogenesis in aortic valves and the observed decrease in sFlt-1 expression in aortic valve stenosis could increase valve inflammation, promoting disease progression. This could be a viable therapeutic target in treating this disease.

Multimodality imaging in aortic stenosis: new diagnostic and therapeutic frontiers

The advent of transcatheter aortic valve implantation has revolutionized the treatment of calcific aortic valve stenosis. Elderly patients who were previously considered inoperable have currently an efficacious and safe therapy that provides better survival. In addition, current practice guidelines tend to recommend earlier intervention to avoid the irreversible consequences of long-lasting pressure overload caused by the stenotic aortic valve. Appropriate timing of the intervention relies significantly on imaging techniques that provide information on the severity of the aortic stenosis as well as on the hemodynamic consequences and cardiac remodeling. While left ventricular ejection fraction remains one of the main functional parameters for risk stratification in patients with severe aortic stenosis, advances in imaging techniques have provided new structural and functional parameters that allow the identification of patients who will benefit from intervention before the occurrence of symptoms or irreversible cardiac damage. Furthermore, ongoing research aiming to identify the medical therapies that can effectively halt the progression of aortic stenosis relies heavily on imaging endpoints, and new imaging techniques that characterize the metabolic activity of calcific aortic stenosis have been proposed to monitor the effects of these therapies. The present review provides an up-to-date overview of the imaging advances that characterizes the pathophysiology and that have changed the management paradigm of aortic stenosis.

Association of aortic arch and aortic valve calcifications with cardiovascular risk in patients on maintenance hemodialysis

Introduction

This study aimed to investigate the association of aortic arch calcification (AoAC) and aortic valve calcification (AVC) with major adverse cardiovascular events (MACE) and cardiovascular and all-cause mortality in patients on maintenance hemodialysis (MHD).

Methods

This study enrolled 297 adult patients with end-stage kidney disease who were on MHD. They were divided into those with an AoAC score <2 without AVC (n = 70, 23.6%), those with an AoAC score <2 with AVC (n = 96, 32.3%), and those with an AoAC score ≥2 regardless of AVC status (n = 131, 44.1%). We analyzed the risks of MACE, cardiovascular and overall mortality among the three groups using Cox proportional hazard analyses. Survival probabilities were estimated using the log-rank test via the Kaplan-Meier method.

Results

Kaplan-Meier analysis revealed that the MACE-free rate and the survival rates of cardiovascular and overall mortality were significantly higher in adult chronic hemodialysis patients with AoAC score <2 without AVC, followed by those with AoAC score <2 with AVC, and then those with AoAC score ≥2 (log-rank test; all p < 0.01). The grade of AoAC is a significant risk factor for MACE, cardiovascular mortality, and overall mortality after adjusting for age and gender Relative to AoAC score <2 without AVC, adult chronic hemodialysis patients with AoAC score ≥2 remained an independently significantly risk factor of MACE (adjusted hazard ratio, 2.17; 95% confidence interval 1.11-4.20; p = 0.023) after adjusting for age, sex, and all significant variables in baseline characteristics.

Conclusion

AoAC grade was positively correlated with a higher risk of MACE and cardiovascular and overall mortality. Furthermore, the presence of AVC modified the adverse cardiovascular risk associated with AoAC in patients on MHD.

Direct relationship between transvalvular velocity and cardiac dysfunction, morbidity, and mortality in patients with aortic stenosis

OBJECTIVE

Current guidelines recommend intervention in subjects with severe symptomatic aortic stenosis (AS), even though any degree of AS is associated with a higher risk of mortality. We investigated the association between the degree of AS, delineated by transvalvular flow velocity, and patient morbidity and mortality.

METHODS

Medically managed patients aged 40-95 years with maximum flow velocity (V_max ) by echocardiography between 2013 and 2018 were stratified into five groups (A-E) based on the 75th, 90th, 97.5th, and the 99th percentiles of V_max distribution. Patient characteristics, cardiac structural changes, and end-organ disease were compared using Kruskal-Wallis and Cochran-Armitage tests. Mortality over a median of 2.8 (1.52-4.8) years was compared using Kaplan-Meier curves and risk estimates were derived from the Cox model.

RESULTS

The V_max was reported in 37,131 patients. There was a steady increase (from Group A towards E) in age, Caucasian race, structural cardiac changes, end-organ morbidities, and all-cause mortality. In reference to Group A, there as an increased risk of mortality in Groups B (hazard ratio [HR] = 1.3; confidence interval [CI]: 1.2-1.35; p < .0001), C (HR = 1.5; CI: 1.4-1.6; p < .0001), and D (HR = 1.8; CI: 1.6-2; p < .0001), with an exponential increase in Group E (HR = 2.5; CI: 2.2-2.8; p < .0001).

CONCLUSIONS

A direct, strong correlation exists between the degree of AS and cardiac structural changes and mortality. Patients with V_max  ≥ 97.5th percentile (≥3.2 m/s) might benefit from early intervention.

Integrating hemodynamics with ventricular and valvular remodeling in aortic stenosis. A paradigm shift in therapeutic decision making

Aortic valve stenosis (AS) has traditionally been approached in hemodynamic terms. Although hemodynamics and symptoms have formed the basis of recommending interventional treatment in AS, other factors reflecting left ventricular and valvular and/or vascular remodeling are equally important for the prognosis and outcome of patients with AS. Left ventricular and valvular/vascular remodeling in AS do not consistently correlate with hemodynamic severity of AS. Those remodeling changes are reflected and can be detected by a variety of novel laboratory and imaging techniques, including biomarkers, echocardiography, cardiac magnetic resonance and gated Computer Tomography (CT) imaging. Taking all those elements into Heart Team therapeutic decision making in patients with AS, can significantly improve appropriate patient selection for interventional treatment and patient outcomes. We review this novel approach and propose a simple algorithm for decision making by the Heart Team, in patients with moderate or severe AS.

Cellular Senescence, Aging and Non-Aging Processes in Calcified Aortic Valve Stenosis: From Bench-Side to Bedside

Aortic valve stenosis (AS) is the most common valvular heart disease. The incidence of AS increases with age, however, a significant proportion of elderly people have no significant AS, indicating that both aging and nonaging pathways are involved in the pathomechanism of AS. Age-related and stress-induced cellular senescence accompanied by further active processes represent the key elements of AS pathomechanism. The early stage of aortic valve degeneration involves dysfunction and disruption of the valvular endothelium due to cellular senescence and mechanical stress on blood flow. These cells are replaced by circulating progenitor cells, but in an age-dependent decelerating manner. When endothelial denudation is no longer replaced by progenitor cells, the path opens for focal lipid deposition, initiating subsequent oxidation, inflammation and micromineralisation. Later stages of AS feature a complex active process with extracellular matrix remodeling, fibrosis and calcification. Echocardiography is the gold standard method for diagnosing aortic valve disease, although computed tomography and cardiac magnetic resonance are useful additional imaging methods. To date, no medical treatment has been proven to halt the progression of AS. Elucidation of differences and similarities between vascular and valvular calcification pathomechanisms may help to find effective medical therapy and reduce the increasing health burden of the disease.

Inhibition of advanced glycation end product formation and serum protein infiltration in bioprosthetic heart valve leaflets: Investigations of anti-glycation agents and anticalcification interactions with ethanol pretreatment

Bioprosthetic heart valves (BHV) fabricated from heterograft tissue, such as glutaraldehyde pretreated bovine pericardium (BP), are the most frequently used heart valve replacements. BHV durability is limited by structural valve degeneration (SVD), mechanistically associated with calcification, advanced glycation end products (AGE), and serum protein infiltration. We investigated the hypothesis that anti-AGE agents, Aminoguanidine, Pyridoxamine [PYR], and N-Acetylcysteine could mitigate AGE-serum protein SVD mechanisms in vitro and in vivo, and that these agents could mitigate calcification or demonstrate anti-calcification interactions with BP pretreatment with ethanol. In vitro, each of these agents significantly inhibited AGE-serum protein infiltration in BP. However, in 28-day rat subdermal BP implants only orally administered PYR demonstrated significant inhibition of AGE and serum protein uptake. Furthermore, BP PYR preincubation of BP mitigated AGE-serum protein SVD mechanisms in vitro, and demonstrated mitigation of both AGE-serum protein uptake and reduced calcification in vivo in 28-day rat subdermal BP explants. Inhibition of BP calcification as well as inhibition of AGE-serum protein infiltration was observed in 28-day rat subdermal BP explants pretreated with ethanol followed by PYR preincubation. In conclusion, AGE-serum protein and calcification SVD pathophysiology are significantly mitigated by both PYR oral therapy and PYR and ethanol pretreatment of BP.

Association Between Omega-3 Fatty Acid Levels and Aortic Valve Calcium (from the Multi-Ethnic Study of Atherosclerosis)

Calcific aortic valve disease, a condition of chronic inflammation, is associated with increased cardiovascular events and all-cause mortality. Omega-3 fatty acids (O3FAs) reduce both acute and chronic inflammation, but their associations with aortic valve calcium (AVC) have not been studied. The Multi-Ethnic Study of Atherosclerosis is a prospective cohort study of 6,814 adults without clinical cardiovascular disease. Plasma fatty acid levels and cardiac computed tomography (CT) scans were performed at baseline, and CT scans were performed at subsequent clinical visits over a median 9-year period. We assessed whether plasma levels of O3FAs and their species correlate with the presence, severity, and progression of AVC measured by CT in Multi-Ethnic Study of Atherosclerosis. The mean age of the 6,510 included participants with baseline fatty acid levels, AVC, and covariate data was 62.1 ± 10.2 years, and 47.1% of the participants were male. Race distribution was 38.6% White, 27.2% Black, 22.1% Hispanic/Latino, and 12.1% Chinese. Among the 6,510 participants, 5,884 had a subsequent CT scan, and 3,304 had a third CT scan with AVC measurements. At baseline, 862 participants (13.2%) had prevalent AVC (Agatston score >0), and were more likely to be of older age, male, of the White race, have a lower education level, and have co-morbidities that are associated with a higher risk for AVC. Plasma tertiles of eicosapentaenoic acid, docosahexaenoic acid, and total O3FA were not associated with prevalent AVC at baseline, incident AVC, or change in AVC. In conclusion, plasma levels of O3FAs in subjects not routinely supplemented with O3FAs are not useful for predicting the presence or development of AVC. Whether high plasma O3FA levels, achievable by high-dose O3FA over-the-counter supplementation or pharmacotherapy, is associated with AVC requires further investigation.

Incidence, risk factors and predictors of cardiovascular mortality for aortic stenosis among patients with diabetes mellitus

AIMS

To find the incidence, risk factors and predictors of cardiovascular (CV) mortality for aortic stenosis (AS) in patients with type 2 diabetes mellitus (T2DM).

METHODS

Between 2014 and 2019, 20,979 patients with T2DM who underwent echocardiography were enrolled for analysis. The mean follow-up period was 34 months. Multiple risk factors and outcomes for patients with and without AS were presented.

RESULTS

AS was present in 776 (3.70%) patients. Age, female, chronic kidney disease, hyperlipidemia, and peripheral arterial disease statistically increased risk of AS. The CV mortality (adjusted hazard ratio [aHR] = 1.97; 95% confidence interval [CI] 1.336 - 2.906, p < 0.001) and risk of hospitalization for heart failure (HHF) (aHR = 1.73, 95% CI 1.442-2.082, p < 0.001) were significantly increased in patients with AS, without significant differences in acute myocardial infarction and stroke. Severity of AS, body mass index (<27 kg/m²), hypertension, hyperuricemia, left ventricular dysfunction (ejection fraction < 50%), and hematocrit (<38%) were significantly associated with increased CV mortality and HHF.

CONCLUSIONS

AS was associated with an increased risk of CV mortality and HHF in patients with T2DM.

Contribution of Oxidative Stress (OS) in Calcific Aortic Valve Disease (CAVD): From Pathophysiology to Therapeutic Targets

Calcific aortic valve disease (CAVD) is a major cause of cardiovascular mortality and morbidity, with increased prevalence and incidence. The underlying mechanisms behind CAVD are complex, and are mainly illustrated by inflammation, mechanical stress (which induces prolonged aortic valve endothelial dysfunction), increased oxidative stress (OS) (which trigger fibrosis), and calcification of valve leaflets. To date, besides aortic valve replacement, there are no specific pharmacological treatments for CAVD. In this review, we describe the mechanisms behind aortic valvular disease, the involvement of OS as a fundamental element in disease progression with predilection in AS, and its two most frequent etiologies (calcific aortic valve disease and bicuspid aortic valve); moreover, we highlight the potential of OS as a future therapeutic target.

Technical Aspects and Development of Transcatheter Aortic Valve Implantation

Aortic stenosis is the most common valve disease requiring surgery or percutaneous treatment. Since the first-in-man implantation in 2002 we have witnessed incredible progress in transcatheter aortic valve implantation (TAVI). In this article, we review the technical aspects of TAVI development with a look at the future. Durability, low thrombogenicity, good hydrodynamics, biocompatibility, low catheter profile, and deployment stability are the attributes of an ideal TAVI device. Two main design types exist-balloon-expandable and self-expanding prostheses. Balloon-expandable prostheses use a cobalt-chromium alloy frame providing high radial strength and radiopacity, while the self-expanding prostheses use a nickel-titanium (Nitinol) alloy frame, which expands to its original shape once unsheathed and heated to the body temperature. The valve is sewn onto the frame and consists of the porcine or bovine pericardium, which is specially treated to prevent calcinations and prolong durability. The lower part of the frame can be covered by polyethylene terephthalate fabric or a pericardial skirt, providing better sealing between the frame and aortic annulus. The main future challenges lie in achieving lower rates of paravalvular leaks and new pacemaker implantations following the procedure, lower delivery system profiles, more precise positioning, longer durability, and a good hemodynamic profile. Patient-specific design and the use of autologous tissue might solve these issues.

Molecular Imaging of Aortic Valve Stenosis with Positron Emission Tomography

Aortic valve stenosis (AVS) is an increasingly prevalent disease in our aging population. Although multiple risk factors for AVS have been elucidated, medical therapies capable of slowing down disease progression remain unavailable. Molecular imaging technologies are opening up avenues for the non-invasive assessment of disease progression, allowing the assessment of (early) medical interventions. This review will focus on the role of positron emission tomography of the aortic valve with 18F-fluorodeoxyglucose and 18F-sodium fluoride but will also shed light on novel tracers which have potential in AVS, ranging from the healthy aortic valve to end-stage valvular disease.

Evolution and Prognostic Impact of Cardiac Damage After Aortic Valve Replacement

BACKGROUND

The impact of aortic valve replacement (AVR) on progression/regression of extra-valvular cardiac damage and its association with subsequent prognosis is unknown.

OBJECTIVES

To describe evolution of cardiac damage post-AVR and its association with outcomes.

METHODS

Patients undergoing transcatheter or surgical AVR from the PARTNER 2 and 3 trials were pooled and classified by cardiac damage stage at baseline and 1-year (Stage 0, no damage; Stage 1, left ventricular damage; Stage 2, left atrial or mitral valve damage; Stage 3, pulmonary vasculature or tricuspid valve damage; Stage 4, right ventricular damage). Proportional hazards models determined association between change in cardiac damage post-AVR and 2-year outcomes.

RESULTS

Among 1974 patients, 121 (6.1%) were Stage 0, 287 (14.5%) Stage 1, 1014 (51.4%) Stage 2, 412 (20.9%) Stage 3, and 140 (7.1%) Stage 4 pre-AVR. Two-year mortality was associated with extent of cardiac damage at baseline and 1-year. Compared with baseline, cardiac damage improved in ∼15%, remained unchanged in ∼60%, and worsened in ∼25% of patients at 1-year. One-year change in cardiac damage stage was independently associated with mortality (adjHR for improvement=0.49; no change=1.0; worsening=1.95; p=0.023) and composite of death or heart failure hospitalization (adjHR for improvement=0.60; no change=1.0; worsening=2.25; p<0.001) at 2 years.

CONCLUSION

In patients undergoing AVR, extent of extravalvular cardiac damage at baseline and its change at 1-year have important prognostic implications. These findings suggest that earlier detection of AS and intervention prior to development of irreversible cardiac damage may improve global cardiac function and prognosis.

Role of oxidative stress in calcific aortic valve disease and its therapeutic implications

Calcific aortic valve disease (CAVD) is the end result of active cellular processes that lead to the progressive fibrosis and calcification of aortic valve leaflets. In western populations, CAVD is a significant cause of cardiovascular morbidity and mortality, and in the absence of effective drugs, it will likely represent an increasing disease burden as populations age. As there are currently no pharmacological therapies available for preventing, treating, or slowing the development of CAVD, understanding the mechanisms underlying the initiation and progression of the disease is important for identifying novel therapeutic targets. Recent evidence has emerged of an important causative role for reactive oxygen species (ROS)-mediated oxidative stress in the pathophysiology of CAVD, inducing the differentiation of valve interstitial cells into myofibroblasts and then osteoblasts. In this review, we focus on the roles and sources of ROS driving CAVD and consider their potential as novel therapeutic targets for this debilitating condition.

BMP7-based peptide agonists of BMPR1A protect the left ventricle against pathological remodeling induced by pressure overload

Aortic stenosis (AS) exposes the left ventricle (LV) to pressure overload leading to detrimental LV remodeling and heart failure. In animal models of cardiac injury or hemodynamic stress, bone morphogenetic protein-7 (BMP7) protects LV against remodeling by counteracting TGF-β effects. BMP receptor 1A (BMPR1A) might mediate BMP7 antifibrotic effects. Herein we evaluated BMP7-based peptides, THR123 and THR184, agonists of BMPR1A, as cardioprotective drugs in a pressure overload model. We studied patients with AS, mice subjected to four-week transverse aortic constriction (TAC) and TAC release (de-TAC). The LV of AS patients and TAC mice featured Bmpr1a downregulation. Also, pSMAD1/5/(8)9 was reduced in TAC mice. Pre-emptive treatment of mice with THR123 and THR184, during the four-week TAC period, normalized pSMAD1/5/(8)9 levels in the LV, attenuated overexpression of remodeling-related genes (Col 1α1, β-MHC, BNP), palliated structural damage (hypertrophy and fibrosis) and alleviated LV dysfunction (systolic and diastolic). THR184 administration, starting fifteen days after TAC, halted the ongoing remodeling and partially reversed LV dysfunction. The reverse remodeling after pressure overload release was facilitated by THR184. Both peptides diminished the TGF-β1-induced hypertrophic gene program in cardiomyocytes, collagen transcriptional activation in fibroblasts, and differentiation of cardiac fibroblasts to myofibroblasts. Molecular docking suggests that both peptides bind with similar binding energies to the BMP7 binding domain at the BMPR1A. The present study results provide a preclinical proof-of-concept of potential therapeutic benefits of BMP7-based small peptides, which function as agonists of BMPR1A, against the pathological LV remodeling in the context of aortic stenosis.

Validation of aortic valve pressure gradient quantification using semi-automated 4D flow CMR pipeline

OBJECTIVE

Doppler echocardiographic aortic valve peak velocity and peak pressure gradient assessment across the aortic valve (AV) is the mainstay for diagnosing aortic stenosis. Four-dimensional flow cardiovascular magnetic resonance (4D flow CMR) is emerging as a valuable diagnostic tool for estimating the peak pressure drop across the aortic valve, but assessment remains cumbersome. We aimed to validate a novel semi-automated pipeline 4D flow CMR method of assessing peak aortic value pressure gradient (AVPG) using the commercially available software solution, CAAS MR Solutions, against invasive angiographic methods.

RESULTS

We enrolled 11 patients with severe AS on echocardiography from the EurValve programme. All patients had pre-intervention doppler echocardiography, invasive cardiac catheterisation with peak pressure drop assessment across the AV and 4D flow CMR. The peak AVPG was 51.9 ± 35.2 mmHg using the invasive pressure drop method and 52.2 ± 29.2 mmHg for the 4D flow CMR method (semi-automated pipeline), with good correlation between the two methods (r = 0.70, p = 0.017). Assessment of AVPG by 4D flow CMR using the novel semi-automated pipeline method shows excellent agreement to invasive assessment when compared to doppler-based methods and advocate for its use as complementary to echocardiography.

Differential BMP Signaling Mediates the Interplay Between Genetics and Leaflet Numbers in Aortic Valve Calcification

Expression of a neuropilin-like protein, DCBLD2, is reduced in human calcific aortic valve disease (CAVD). DCBLD2-deficient mice develop bicuspid aortic valve (BAV) and CAVD, which is more severe in BAV mice compared with tricuspid littermates. In vivo and in vitro studies link this observation to up-regulated bone morphogenic protein (BMP)2 expression in the presence of DCBLD2 down-regulation, and enhanced BMP2 signaling in BAV, indicating that a combination of genetics and BAV promotes aortic valve calcification and stenosis. This pathway may be a therapeutic target to prevent CAVD progression in BAV.

Uncoupling the Vicious Cycle of Mechanical Stress and Inflammation in Calcific Aortic Valve Disease

Calcific aortic valve disease (CAVD) is a common acquired valvulopathy, which carries a high burden of mortality. Chronic inflammation has been postulated as the predominant pathophysiological process underlying CAVD. So far, no effective medical therapies exist to halt the progression of CAVD. This review aims to outline the known pathways of inflammation and calcification in CAVD, focussing on the critical roles of mechanical stress and mechanosensing in the perpetuation of valvular inflammation. Following initiation of valvular inflammation, dysregulation of proinflammatory and osteoregulatory signalling pathways stimulates endothelial-mesenchymal transition of valvular endothelial cells (VECs) and differentiation of valvular interstitial cells (VICs) into active myofibroblastic and osteoblastic phenotypes, which in turn mediate valvular extracellular matrix remodelling and calcification. Mechanosensitive signalling pathways convert mechanical forces experienced by valve leaflets and circulating cells into biochemical signals and may provide the positive feedback loop that promotes acceleration of disease progression in the advanced stages of CAVD. Mechanosensing is implicated in multiple aspects of CAVD pathophysiology. The mechanosensitive RhoA/ROCK and YAP/TAZ systems are implicated in aortic valve leaflet mineralisation in response to increased substrate stiffness. Exposure of aortic valve leaflets, endothelial cells and platelets to high shear stress results in increased expression of mediators of VIC differentiation. Upregulation of the Piezo1 mechanoreceptor has been demonstrated to promote inflammation in CAVD, which normalises following transcatheter valve replacement. Genetic variants and inhibition of Notch signalling accentuate VIC responses to altered mechanical stresses. The study of mechanosensing pathways has revealed promising insights into the mechanisms that perpetuate inflammation and calcification in CAVD. Mechanotransduction of altered mechanical stresses may provide the sought-after coupling link that drives a vicious cycle of chronic inflammation in CAVD. Mechanosensing pathways may yield promising targets for therapeutic interventions and prognostic biomarkers with the potential to improve the management of CAVD.

[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.

Serotonin—A Driver of Progressive Heart Valve Disease

It is well known that some serotoninergic drugs and neuroendocrine tumors producing serotonin (5-HT) may induce valvular heart disease by stimulation of proliferation of valvular cells via interaction with a 5-HT receptor type 2B. Serotonin could play a role in the pathogenesis of progressive valvular disease for example as a complication of rheumatic fever, in patients with congenital bicuspid aortic valves or in degenerative aortic valve stenosis. The initial inflammation in acute rheumatic fever seems to affect both right and the left-side cardiac valves. Some patients develop chronic right-sided valve disease, particularly in connection with septum defects, though left-sided valves typically are predominantly affected, indicating that high flow velocity and systemic pressure close to the valves may be central in the pathogenesis. Serotonin is transported in granules in blood platelets. Changes in platelet number and concentrations of substances released from platelets in patients with valvular disease indicate that serotonin is released locally by shear stress when passing through an abnormal valve. Accordingly, any functional changes (like bicuspid aortic valves and changes secondary to degeneration) in the valves may progress due to locally released serotonin. Unfortunately, due to serotonin release by sampling and preparation of plasma, local serotonin assessment is not possible. Nevertheless, we suggest that serotonin may play a role in valvular disease in general and that patients may benefit from treatment reducing the effect of serotonin on the heart.

N-Acetylcysteine Inhibits Aortic Stenosis Progression in a Murine Model by Blocking Shear-Induced Activation of Platelet Latent Transforming Growth Factor Beta 1

Objective: Aortic stenosis (AS) is characterized by narrowing of the aortic valve opening, resulting in peak blood flow velocity that induces high wall shear stress (WSS) across the valve. Severe AS leads to heart failure and death. There is no treatment available for AS other than valve replacement. Platelet-derived transforming growth factor beta 1 (TGF-β1) partially contributes to AS progression in mice, and WSS is a potent activator of latent TGF-β1. N-acetylcysteine (NAC) inhibits WSS-induced TGF-β1 activation in vitro. We hypothesize that NAC will inhibit AS progression by inhibiting WSS-induced TGF-β1 activation. Approach: We treated a cohort of Ldlr(-/-)Apob(100/100) low density lipoprotein receptor (LDLR) mice fed a high-fat diet with NAC (2% in drinking water) at different stages of disease progression and measured its effect on AS progression and TGF-β1 activation. Results: Short-term NAC treatment inhibited AS progression in mice with moderate and severe AS relative to controls, but not in LDLR mice lacking platelet-derived TGF-β1 (TGF-β1platlet-KO-LDLR). NAC treatment reduced TGF-β signaling, p-Smad2 and collagen levels, and mesenchymal transition from isolectin B4 and CD45-positive cells in LDLR mice. Mechanistically, NAC treatment resulted in plasma NAC concentrations ranging from 75.5 to 449.2 ng/mL, which were sufficient to block free thiol labeling of plasma proteins and reduce active TGF-β1 levels without substantially affecting reactive oxygen species-modified products in valvular cells. Conclusions: Short-term treatment with NAC inhibits AS progression by inhibiting WSS-induced TGF-β1 activation in the LDLR mouse model of AS, motivating a clinical trial of NAC and/or other thiol-reactive agent(s) as a potential therapy for AS.

Evaluating Medical Therapy for Calcific Aortic Stenosis: JACC State-of-the-Art Review

Despite numerous promising therapeutic targets, there are no proven medical treatments for calcific aortic stenosis (AS). Multiple stakeholders need to come together and several scientific, operational, and trial design challenges must be addressed to capitalize on the recent and emerging mechanistic insights into this prevalent heart valve disease. This review briefly discusses the pathobiology and most promising pharmacologic targets, screening, diagnosis and progression of AS, identification of subgroups that should be targeted in clinical trials, and the need to elicit the patient voice earlier rather than later in clinical trial design and implementation. Potential trial end points and tools for assessment and approaches to implementation and design of clinical trials are reviewed. The efficiencies and advantages offered by a clinical trial network and platform trial approach are highlighted. The objective is to provide practical guidance that will facilitate a series of trials to identify effective medical therapies for AS resulting in expansion of therapeutic options to complement mechanical solutions for late-stage disease.

Antihypertensive therapy in patients with moderate to severe aortic stenosis

ABSTRACT

Patients with aortic stenosis are at risk for developing hypertension. The selection of antihypertensives is a topic of debate due to a lack of consensus regarding their safety. This article provides an overview of antihypertensives used in patients with aortic stenosis, focusing on renin-angiotensin system inhibitors, beta-blockers, diuretics, and vasodilators.