Prediction of Mortality and Heart Failure Hospitalization After Transcatheter Tricuspid Valve Interventions: Validation of TRISCORE.

BACKGROUND: Data on the prognostic role of the TRI-SCORE in patients undergoing transcatheter tricuspid valve intervention (TTVI) are limited. OBJECTIVES: The aim of this study was to evaluate the performance of the TRI-SCORE in predicting outcomes of patients undergoing TTVI. METHODS: TriValve (Transcatheter Tricuspid Valve Therapies) is a large multicenter multinational registry including patients undergoing TTVI. The TRI-SCORE is a risk model recently proposed to predict in-hospital mortality after tricuspid valve surgery. The TriValve population was stratified based on the TRI-SCORE tertiles. The outcomes of interest were all-cause death and all-cause death or heart failure hospitalization. Procedural complications and changes in NYHA functional class were also reported. RESULTS: Among the 634 patients included, 223 patients (35.2%) had a TRI-SCORE between 0 and 5, 221 (34.8%) had 6 or 7, and 190 (30%) had ≥8 points. Postprocedural blood transfusion, acute kidney injury, new atrial fibrillation, and in-hospital mortality were more frequent in the highest TRI-SCORE tertile. Postprocedure length of stay increased with a TRI-SCORE increase. A TRI-SCORE ≥8 was associated with an increased risk of 30-day all-cause mortality and all-cause mortality and the composite endpoint assessed at a median follow-up of 186 days (OR: 3.00; 95% CI: 1.38-6.55; HR: 2.17; 95% CI: 1.78-4.13; HR: 2.08, 95% CI: 1.57-2.74, respectively) even after adjustment for procedural success and EuroSCORE II or Society of Thoracic Surgeons Predicted Risk of Mortality. The NYHA functional class improved across all TRI-SCORE values. CONCLUSIONS: In the TriValve registry, the TRI-SCORE has a suboptimal performance in predicting clinical outcomes. However, a TRISCORE ≥8 is associated with an increased risk of clinical events and a lack of prognostic benefit after successful TTVI.

Baseline NT-proBNP predicts acute kidney injury following transcatheter aortic valve implantation.

BACKGROUND/PURPOSE: Acute kidney injury (AKI) after transcatheter aortic valve implantation (TAVI) increases morbidity and mortality. Our study aimed to investigate the role of baseline N-terminal pro B-type natriuretic peptide (NT-proBNP) as a predictor of AKI following TAVI. METHODS: All consecutive TAVI patients were included in the analysis, except patients with dialysis and those with a GFR < 15 ml/min/1.73 m2 at baseline. Rates of AKI after TAVI were assessed according to the updated valve academic research consortium definitions using AKIN classification in three stages. NT-proBNP was measured at baseline. One-year mortality rates were assessed. RESULTS: We included 1973 patients treated with TAVI between January 2006 and December 2016. Median [IQR] age was 81.0 [77.0;84.0] years, the STS score was 6.2 [3.9;9.0], and the logEuroScore was 14.5 [9.0;23.0]. 30-day and one-year mortality was 5.1 % and 16.1 % for all patients, respectively. Multivariate analysis revealed that patients with NT-proBNP levels higher than two times above the upper level of normal (ULN) had an increased risk for AKI after TAVI compared to patients with NT-proBNP levels < 2× ULN (OR 1.40 [1.03-1.91]). CONCLUSIONS: Routine assessment of baseline NT-proBNP levels might be an additional tool to identify patients at increased risk for AKI after TAVI.

Implications of tricuspid regurgitation and right ventricular volume overload in patients with heart failure with preserved ejection fraction.

AIMS: The aim of this study was to assess the pathophysiological implications of severe tricuspid regurgitation (TR) in patients with heart failure with preserved ejection fraction (HFpEF) by using tricuspid transcatheter edge-to-edge repair (T-TEER) as a model of right ventricular (RV) volume overload relief. METHODS AND RESULTS: This prospective interventional single arm trial (NCT04782908) included patients with invasively diagnosed HFpEF. The following parameters were prospectively assessed before and after T-TEER: left ventricular (LV) diastolic properties by invasive pressure-volume loop recordings; biventricular time-volume curves and function as well as septal curvature by cardiac magnetic resonance imaging; strain analyses for timing of septal motion. Overall, 20 patients (median age 78, interquartile range [IQR] 72-83 years, 65% female) were included. T-TEER reduced TR by a median of 2 (of 5) grades (IQR 2-1). T-TEER increased LV stroke volume and LV end-diastolic volume (LVEDV) (p < 0.001), without increasing LV end-diastolic pressure (LVEDP) (p = 0.094), consequently diastolic function improved with a reduction in LVEDP/LVEDV (p = 0.001) and a rightward shift of the end-diastolic pressure-volume relationship. The increase in LVEDV correlated with a decrease in RV end-diastolic volume (p < 0.001) and LV transmural pressure increased (p = 0.028). Secondary to a decrease in early RV filling, improvements in early LV filling were observed, correlating with an alleviation of leftwards bowing of the septum (p < 0.01, respectively). CONCLUSION: Diastolic LV properties in patients with HFpEF and severe TR are importantly determined by ventricular interaction in the setting of RV volume overload. T-TEER reduces RV volume overload and improves biventricular interaction and physiology.

Nuclear magnetic resonance spectroscopy to quantify major extracellular matrix components in fibro-calcific aortic valve disease.

Fibro-calcific aortic valve disease (FCAVD) is a pathological condition marked by overt fibrous and calcific extracellular matrix (ECM) accumulation that leads to valvular dysfunction and left ventricular outflow obstruction. Costly valve implantation is the only approved therapy. Multiple pharmacological interventions are under clinical investigation, however, none has proven clinically beneficial. This failure of translational approaches indicates incomplete understanding of the underlying pathomechanisms and may result from a limited toolbox of scientific methods to assess the cornerstones of FCAVD: lipid deposition, fibrous and calcific ECM accumulation. In this study, we evaluated magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy to both, qualitatively and quantitatively assess these key elements of FCAVD pathogenesis. NMR spectra showed collagen, elastin, triacylglycerols, and phospholipids in human control and FCAVD tissue samples (n = 5). Calcification, measured by the hydroxyapatite content, was detectable in FCAVD tissues and in valve interstitial cells under procalcifying media conditions. Hydroxyapatite was significantly higher in FCAVD tissues than in controls (p < 0.05) as measured by 31P MAS NMR. The relative collagen content was lower in FCAVD tissues vs. controls (p < 0.05). Overall, we demonstrate the versatility of NMR spectroscopy as a diagnostic tool in preclinical FCAVD assessment.

Characteristics and outcomes of patients with atrial versus ventricular secondary tricuspid regurgitation undergoing tricuspid transcatheter edge-to-edge repair - Results from the TriValve registry.

AIM: Functional or secondary tricuspid regurgitation (STR) is the most common phenotype of tricuspid regurgitation (TR) with atrial STR (ASTR) and ventricular STR (VSTR) being recently identified as two distinct entities. Data on tricuspid transcatheter edge-to-edge repair (T-TEER) in patients with STR according to phenotype (i.e. ASTR vs. VSTR) are lacking. The aim of this study was to assess characteristics and outcomes of patients with ASTR versus VSTR undergoing T-TEER. METHODS AND RESULTS: Patients with STR undergoing T-TEER were selected from the Transcatheter Tricuspid Valve Therapies (TriValve) registry. ASTR was defined by (i) left ventricular ejection fraction ≥50%, (ii) atrial fibrillation, and (iii) systolic pulmonary artery pressure <50 mmHg. Patients not matching these criteria were classified as VSTR. Patients with primary TR and cardiac implantable electronic device were excluded. Key endpoints included procedural success and survival at follow-up. A total of 298 patients were enrolled in the study: 65 (22%) with ASTR and 233 (78%) with VSTR. Procedural success was similar in the two groups (80% vs. 83% for ASTR vs. VSTR, p = 0.56) and TEER was effective in reducing TR in both groups (from 97% of patients with baseline TR ≥3+ to 23% in ASTR and to 15% in VSTR, all p = 0.001). At 12-month follow-up, survival was significantly higher in the ASTR versus VSTR cohort (91% vs. 72%, log-rank p = 0.02), with VSTR being an independent predictor of mortality at multivariable analysis (hazard ratio 4.75). CONCLUSIONS: In a real-world, multicentre registry, T-TEER was effective in reducing TR grade in both ASTR and VSTR. At 12-month follow-up, ASTR showed better survival than VSTR.

High resolution monitoring of valvular interstitial cell driven pathomechanisms in procalcific environment using label-free impedance spectroscopy.

Introduction: Fibro-calcific aortic valve disease has high prevalence and is associated with significant mortality. Fibrotic extracellular matrix (ECM) remodeling and calcific mineral deposition change the valvular microarchitecture and deteriorate valvular function. Valvular interstitial cells (VICs) in profibrotic or procalcifying environment are frequently used in vitro models. However, remodeling processes take several days to weeks to develop, even in vitro. Continuous monitoring by real-time impedance spectroscopy (EIS) may reveal new insights into this process. Methods: VIC-driven ECM remodeling stimulated by procalcifying (PM) or profibrotic medium (FM) was monitored by label-free EIS. Collagen secretion, matrix mineralization, viability, mitochondrial damage, myofibroblastic gene expression and cytoskeletal alterations were analyzed. Results and Discussion: EIS profiles of VICs in control medium (CM) and FM were comparable. PM reproducibly induced a specific, biphasic EIS profile. Phase 1 showed an initial impedance drop, which moderately correlated with decreasing collagen secretion (r = 0.67, p = 0.22), accompanied by mitochondrial membrane hyperpolarization and cell death. Phase 2 EIS signal increase was positively correlated with augmented ECM mineralization (r = 0.97, p = 0.008). VICs in PM decreased myofibroblastic gene expression (p < 0.001) and stress fiber assembly compared to CM. EIS revealed sex-specific differences. Male VICs showed higher proliferation and in PM EIS decrease in phase 1 was significantly pronounced compared to female VICs (male minimum: 7.4 ± 4.2%, female minimum: 26.5 ± 4.4%, p < 0.01). VICs in PM reproduced disease characteristics in vitro remarkably fast with significant impact of donor sex. PM suppressed myofibroblastogenesis and favored ECM mineralization. In summary, EIS represents an efficient, easy-to-use, high-content screening tool enabling patient-specific, subgroup- and temporal resolution.

Multiomics of Tissue Extracellular Vesicles Identifies Unique Modulators of Atherosclerosis and Calcific Aortic Valve Stenosis.

BACKGROUND: Fewer than 50% of patients who develop aortic valve calcification have concomitant atherosclerosis, implying differential pathogenesis. Although circulating extracellular vesicles (EVs) act as biomarkers of cardiovascular diseases, tissue-entrapped EVs are associated with early mineralization, but their cargoes, functions, and contributions to disease remain unknown. METHODS: Disease stage-specific proteomics was performed on human carotid endarterectomy specimens (n=16) and stenotic aortic valves (n=18). Tissue EVs were isolated from human carotid arteries (normal, n=6; diseased, n=4) and aortic valves (normal, n=6; diseased, n=4) by enzymatic digestion, (ultra)centrifugation, and a 15-fraction density gradient validated by proteomics, CD63-immunogold electron microscopy, and nanoparticle tracking analysis. Vesiculomics, comprising vesicular proteomics and small RNA-sequencing, was conducted on tissue EVs. TargetScan identified microRNA targets. Pathway network analyses prioritized genes for validation in primary human carotid artery smooth muscle cells and aortic valvular interstitial cells. RESULTS: Disease progression drove significant convergence (P<0.0001) of carotid artery plaque and calcified aortic valve proteomes (2318 proteins). Each tissue also retained a unique subset of differentially enriched proteins (381 in plaques; 226 in valves; q<0.05). Vesicular gene ontology terms increased 2.9-fold (P<0.0001) among proteins modulated by disease in both tissues. Proteomics identified 22 EV markers in tissue digest fractions. Networks of proteins and microRNA targets changed by disease progression in both artery and valve EVs revealed shared involvement in intracellular signaling and cell cycle regulation. Vesiculomics identified 773 proteins and 80 microRNAs differentially enriched by disease exclusively in artery or valve EVs (q<0.05); multiomics integration found tissue-specific EV cargoes associated with procalcific Notch and Wnt signaling in carotid arteries and aortic valves, respectively. Knockdown of tissue-specific EV-derived molecules FGFR2, PPP2CA, and ADAM17 in human carotid artery smooth muscle cells and WNT5A, APP, and APC in human aortic valvular interstitial cells significantly modulated calcification. CONCLUSIONS: The first comparative proteomics study of human carotid artery plaques and calcified aortic valves identifies unique drivers of atherosclerosis versus aortic valve stenosis and implicates EVs in advanced cardiovascular calcification. We delineate a vesiculomics strategy to isolate, purify, and study protein and RNA cargoes from EVs entrapped in fibrocalcific tissues. Integration of vesicular proteomics and transcriptomics by network approaches revealed novel roles for tissue EVs in modulating cardiovascular disease.

Sortilin enhances fibrosis and calcification in aortic valve disease by inducing interstitial cell heterogeneity.

AIMS: Calcific aortic valve disease (CAVD) is the most common valve disease, which consists of a chronic interplay of inflammation, fibrosis, and calcification. In this study, sortilin (SORT1) was identified as a novel key player in the pathophysiology of CAVD, and its role in the transformation of valvular interstitial cells (VICs) into pathological phenotypes is explored. METHODS AND RESULTS: An aortic valve (AV) wire injury (AVWI) mouse model with sortilin deficiency was used to determine the effects of sortilin on AV stenosis, fibrosis, and calcification. In vitro experiments employed human primary VICs cultured in osteogenic conditions for 7, 14, and 21 days; and processed for imaging, proteomics, and transcriptomics including single-cell RNA-sequencing (scRNA-seq). The AVWI mouse model showed reduced AV fibrosis, calcification, and stenosis in sortilin-deficient mice vs. littermate controls. Protein studies identified the transition of human VICs into a myofibroblast-like phenotype mediated by sortilin. Sortilin loss-of-function decreased in vitro VIC calcification. ScRNA-seq identified 12 differentially expressed cell clusters in human VIC samples, where a novel combined inflammatory myofibroblastic-osteogenic VIC (IMO-VIC) phenotype was detected with increased expression of SORT1, COL1A1, WNT5A, IL-6, and serum amyloid A1. VICs sequenced with sortilin deficiency showed decreased IMO-VIC phenotype. CONCLUSION: Sortilin promotes CAVD by mediating valvular fibrosis and calcification, and a newly identified phenotype (IMO-VIC). This is the first study to examine the role of sortilin in valvular calcification and it may render it a therapeutic target to inhibit IMO-VIC emergence by simultaneously reducing inflammation, fibrosis, and calcification, the three key pathological processes underlying CAVD.

Atrial Functional Tricuspid Regurgitation: Novel Definition and Impact on Prognosis.

BACKGROUND: Atrial functional tricuspid regurgitation (atrial TR) has received growing recognition as a TR entity with a distinct cause owing to its independence from valvular tethering as the predominant mechanism underlying TR. However, characterization of atrial TR varies, and a universal definition is lacking. METHODS: In total, 651 patients with significant functional TR were analyzed, including 438 conservatively treated individuals and 213 patients who received transcatheter tricuspid valve repair (TTVR). Based on a clustering approach, we defined atrial TR as tricuspid valve (TV) tenting height ≤10 mm, midventricular right ventricular diameter ≤38 mm, and left ventricular ejection fraction ≥50%. RESULTS: Patients with atrial TR were more often females, had higher right ventricular fractional area change, higher left ventricular ejection fraction, and lower LV end-diastolic diameter, TV tenting area and height, lower right ventricular and tricuspid annular size, enlarged, but lower right atrial area and lower TV effective regurgitant orifice area (all P<0.05). Patients with atrial TR had significantly better long-term survival than non-atrial TR in the conservatively treated TR cohort (P<0.01, n=438). Atrial TR was independently associated with a lower rate of the combined end point of mortality and heart failure hospitalization at 1-year follow-up in the TTVR cohort (hazard ratio, 0.39; P<0.05, n=213). TR degree was significantly reduced after TTVR in non-atrial and atrial TR (P<0.01). Functional parameters significantly improved following TTVR independent of TR cause (P<0.05). CONCLUSIONS: An echocardiography-based atrial TR definition is associated with prognostic relevance in patients with functional TR in conservatively treated TR and after TTVR.

Long-term Follow-up After Transcatheter Aortic Valve Replacement.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) has become the standard of care in the majority of patients with symptomatic severe aortic stenosis. Data on long-term mortality and durability of transcatheter heart valves (THVs) beyond 5 years are limited. Our study aimed to assess elderly and high-risk patients' long-term outcomes treated with TAVR in a prospective single-centre registry focusing on the durability of THVs. METHODS: We included 795 patients with severe calcific aortic stenosis treated by transfemoral TAVR between 2006 and 2011. Echocardiography was performed at baseline; discharge; 1 year; and afterward, annually, until the longest available follow-up. Mortality rates were estimated for 1, 5, 6, 7, and 8 years. The rates of structural valve deterioration (SVD) and bioprosthetic valve failure (BVF) were assessed in accordance with consensus definitions. Outcome measures were adjudicated according to Valve Academic Research Consortium-2 (VARC-2). RESULTS: Median (interquartile range) follow-up time was 1345 (316; 2015) days. One-year, 5-year, 6-year, 7-year, and 8-year overall mortality was 25.4%, 59.0%, 64.6%, 67.9%, and 69.2%, respectively. At 8 years, no significant differences in mortality were found comparing self-expanding vs balloon-expandable valves (69.5% vs 68.0%, P = 0.709) and postdilatation (PD) vs no-PD (69.4% vs 69.2%, P = 0.363). SVD was detected in 26 patients (3.3%), and 19 (2.4%) of the 795 patients had evidence of BVF during follow-up. CONCLUSIONS: Our study demonstrates good long-term results for high-risk patients who were alive up to 8 years after TAVR.

CONTEXTE: Le remplacement valvulaire aortique par cathéter (RVAC) est maintenant la norme de soins dans la majorité des cas de sténose de l'aorte grave symptomatique. On dispose de peu de données sur la mortalité à long terme et sur la durabilité des valves cardiaques transcathéter (VCT) au-delà de 5 ans. Nous avons donc évalué les résultats à long terme, notamment la durabilité des VCT, chez les patients âgés et les patients exposés à un risque élevé traités par RVAC figurant dans un registre prospectif unicentrique. MÉTHODOLOGIE: Notre étude comprenait 795 patients présentant une sténose calcifiée de l'aorte grave traitée par RVAC transfémoral entre 2006 et 2011. Une échocardiographie a été réalisée au départ, à la sortie de l'hôpital, 1 an plus tard et tous les ans par la suite, jusqu'au suivi le plus long disponible. Les taux de mortalité à 1, 5, 6, 7 et 8 ans ont été estimés. Les taux de détérioration structurelle des valves (DSV) et de défaillance de la bioprothèse valvulaire (DBV) ont été évalués selon des définitions établies par consensus. Les mesures des résultats ont été confirmées selon les critères du VARC-2 (Valve Academic Research Consortium-2). RÉSULTATS: La durée médiane (intervalle interquartile) du suivi était de 1 345 (316 à 2 015) jours. Les taux de mortalité globaux s'établissaient comme suit : taux à 1 an : 25,4 %; à 5 ans : 59,0 %; à 6 ans : 64,6 %; à 7 ans : 67,9 % et à 8 ans : 69,2 %. À 8 ans, on n'a noté aucune différence significative en ce qui concerne la mortalité chez les patients ayant reçu une valve auto-expansible comparativement à ceux ayant reçu une valve expansible par ballonnet (69,5 % vs 68,0 %; p = 0,709) et chez ceux ayant subi une post-dilatation ou non (69,4 % vs 69,2 %; p = 0,363). Une DSV a été détectée chez 26 patients (3,3 %), et 19 (2,4 %) des 795 patients ont présenté des signes de DBV pendant la période de suivi. CONCLUSIONS: Notre étude a révélé de bons résultats à long terme chez les patients présentant un risque élevé qui étaient toujours en vie 8 ans après le RVAC.

Elastogenesis Correlates With Pigment Production in Murine Aortic Valve Leaflets.

Objective: Aortic valve (AV) leaflets rely on a precise extracellular matrix (ECM) microarchitecture for appropriate biomechanical performance. The ECM structure is maintained by valvular interstitial cells (VICs), which reside within the leaflets. The presence of pigment produced by a melanocytic population of VICs in mice with dark coats has been generally regarded as a nuisance, as it interferes with histological analysis of the AV leaflets. However, our previous studies have shown that the presence of pigment correlates with increased mechanical stiffness within the leaflets as measured by nanoindentation analyses. In the current study, we seek to better characterize the phenotype of understudied melanocytic VICs, explore the role of these VICs in ECM patterning, and assess the presence of these VICs in human aortic valve tissues. Approach and Results: Immunofluorescence and immunohistochemistry revealed that melanocytes within murine AV leaflets express phenotypic markers of either neuronal or glial cells. These VIC subpopulations exhibited regional patterns that corresponded to the distribution of elastin and glycosaminoglycan ECM proteins, respectively. VICs with neuronal and glial phenotypes were also found in human AV leaflets and showed ECM associations similar to those observed in murine leaflets. A subset of VICs within human AV leaflets also expressed dopachrome tautomerase, a common melanocyte marker. A spontaneous mouse mutant with no aortic valve pigmentation lacked elastic fibers and had reduced elastin gene expression within AV leaflets. A hyperpigmented transgenic mouse exhibited increased AV leaflet elastic fibers and elastin gene expression. Conclusions: Melanocytic VIC subpopulations appear critical for appropriate elastogenesis in mouse AVs, providing new insight into the regulation of AV ECM homeostasis. The identification of a similar VIC population in human AVs suggests conservation across species.

Outcomes of transcatheter tricuspid valve intervention by right ventricular function: a multicentre propensity-matched analysis.

BACKGROUND: Tricuspid regurgitation (TR) has a poor prognosis and limited treatment options and is frequently accompanied by right ventricular (RV) dysfunction. Transcatheter tricuspid valve interventions (TTVI) to reduce TR have been shown to be safe and feasible with encouraging early results. Patient selection for TTVI remains challenging, with the role of right ventricular (RV) function being unknown. AIMS: The aims of this study were 1) to investigate survival in a TTVI-treated patient population and a conservatively treated TR population, and 2) to evaluate the outcome of TTVI as compared to conservative treatment stratified according to the degree of RV function. METHODS: We studied 684 patients from the multicentre TriValve cohort (TTVI cohort) and compared them to 914 conservatively treated patients from two tertiary care centres. Propensity matching identified 213 pairs of patients with severe TR. As we observed a non-linear relationship of RV function and TTVI outcome, we stratified patients according to tricuspid annular plane systolic excursion (TAPSE) to preserved (TAPSE >17 mm), mid-range (TAPSE 13-17 mm) and reduced (TAPSE <13 mm) RV function. The primary outcome was one-year all-cause mortality. RESULTS: TTVI was associated with a survival benefit in patients with severe TR when compared to matched controls (one-year mortality rate: 13.1% vs 25.8%; p=0.031). Of the three RV subgroups, only in patients with mid-range RV function was TTVI associated with an improved survival (p log-rank 0.004). In these patients, procedural success was associated with a reduced hazard ratio for all-cause mortality (HR 0.22; 95% CI: 0.09, 0.57). CONCLUSIONS: TTVI is associated with reduced mortality compared to conservative therapy and might exert its highest treatment effect in patients with mid-range reduced RV function.

Dissecting Calcific Aortic Valve Disease-The Role, Etiology, and Drivers of Valvular Fibrosis.

Calcific aortic valve disease (CAVD) is a highly prevalent and progressive disorder that ultimately causes gradual narrowing of the left ventricular outflow orifice with ensuing devastating hemodynamic effects on the heart. Calcific mineral accumulation is the hallmark pathology defining this process; however, fibrotic extracellular matrix (ECM) remodeling that leads to extensive deposition of fibrous connective tissue and distortion of the valvular microarchitecture similarly has major biomechanical and functional consequences for heart valve function. Significant advances have been made to unravel the complex mechanisms that govern these active, cell-mediated processes, yet the interplay between fibrosis and calcification and the individual contribution to progressive extracellular matrix stiffening require further clarification. Specifically, we discuss (1) the valvular biomechanics and layered ECM composition, (2) patterns in the cellular contribution, temporal onset, and risk factors for valvular fibrosis, (3) imaging valvular fibrosis, (4) biomechanical implications of valvular fibrosis, and (5) molecular mechanisms promoting fibrotic tissue remodeling and the possibility of reverse remodeling. This review explores our current understanding of the cellular and molecular drivers of fibrogenesis and the pathophysiological role of fibrosis in CAVD.

Dynamin-related protein 1 inhibition reduces hepatic PCSK9 secretion.

AIMS: Proteostasis maintains protein homeostasis and participates in regulating critical cardiometabolic disease risk factors including proprotein convertase subtilisin/kexin type 9 (PCSK9). Endoplasmic reticulum (ER) remodeling through release and incorporation of trafficking vesicles mediates protein secretion and degradation. We hypothesized that ER remodeling that drives mitochondrial fission participates in cardiometabolic proteostasis. METHODS AND RESULTS: We used in vitro and in vivo hepatocyte inhibition of a protein involved in mitochondrial fission, dynamin-related protein 1 (DRP1). Here, we show that DRP1 promotes remodeling of select ER microdomains by tethering vesicles at ER. A DRP1 inhibitor, mitochondrial division inhibitor 1 (mdivi-1) reduced ER localization of a DRP1 receptor, mitochondrial fission factor, suppressing ER remodeling-driven mitochondrial fission, autophagy, and increased mitochondrial calcium buffering and PCSK9 proteasomal degradation. DRP1 inhibition by CRISPR/Cas9 deletion or mdivi-1 alone or in combination with statin incubation in human hepatocytes and hepatocyte-specific Drp1-deficiency in mice reduced PCSK9 secretion (-78.5%). In HepG2 cells, mdivi-1 increased low-density lipoprotein receptor via c-Jun transcription and reduced PCSK9 mRNA levels via suppressed sterol regulatory binding protein-1c. Additionally, mdivi-1 reduced macrophage burden, oxidative stress, and advanced calcified atherosclerotic plaque in aortic roots of diabetic Apoe-deficient mice and inflammatory cytokine production in human macrophages. CONCLUSIONS: We propose a novel tethering function of DRP1 beyond its established fission function, with DRP1-mediated ER remodeling likely contributing to ER constriction of mitochondria that drives mitochondrial fission. We report that DRP1-driven remodeling of select ER micro-domains may critically regulate hepatic proteostasis and identify mdivi-1 as a novel small molecule PCSK9 inhibitor.

Left-Atrial Appendage Thrombosis in Patients With Severe Aortic Stenosis Undergoing Transcatheter Aortic Valve Implantation.

BACKGROUND: Data about the impact of left-atrial appendage thrombosis (LAAT) on early safety and mortality in patients undergoing transfemoral transcatheter aortic valve implantation (TF-TAVI) are scarce. We aimed to investigate the prevalence and predictors of LAAT and the outcome associated with this condition in patients treated by TF-TAVI. METHODS: Retrospective data analysis was derived from a prospective single-centre registry comparing patients with and without LAAT regarding early safety at 30 days, according to Valve Academic Research Consortium-2 (VARC-2) and 2-year mortality. RESULTS: LAAT was found in 7.6% of the whole cohort (n = 2527) and in 16.6% in those patients with known pre-existing atrial fibrillation (AF cohort, n = 1099). Compared with controls, patients with LAAT were sicker, indicated by a higher Society of Thoracic Surgeons (STS) score and burden of comorbidities. Neither VARC-2-defined early safety at 30 days nor the rate of stroke was different between LAAT and controls in both the whole (early safety: 29.2% vs 24.2%, P = 0.123; stroke: 5.9% vs 4.7%, P = 0.495) and AF cohort (early safety: 29.1% vs 22.9%, P = 0.072; stroke: 5.6% vs 3.3%, P = 0.142). Evaluating the whole cohort in a univariate analysis, the 2-year mortality was significantly higher in LAAT compared with controls (hazard ratio, 1.41; 95% confidence interval, 1.07-1.86; P = 0.014). However, multivariate analysis of the whole cohort and the AF cohort revealed no association between LAAT and 2-year mortality. CONCLUSIONS: LAAT was frequent in patients undergoing TF-TAVI- in particular, in patients with histories of AF-but it was not associated with an increase in periprocedural complications and did not predict 2-year mortality.

ApoC-III is a novel inducer of calcification in human aortic valves.

Calcific aortic valve disease (CAVD) occurs when subpopulations of valve cells undergo specific differentiation pathways, promoting tissue fibrosis and calcification. Lipoprotein particles carry oxidized lipids that promote valvular disease, but low-density lipoprotein-lowering therapies have failed in clinical trials, and there are currently no pharmacological interventions available for this disease. Apolipoproteins are known promoters of atherosclerosis, but whether they possess pathogenic properties in CAVD is less clear. To search for a possible link, we assessed 12 apolipoproteins in nonfibrotic/noncalcific and fibrotic/calcific aortic valve tissues by proteomics and immunohistochemistry to understand if they were enriched in calcified areas. Eight apolipoproteins (apoA-I, apoA-II, apoA-IV, apoB, apoC-III, apoD, apoL-I, and apoM) were enriched in the calcific versus nonfibrotic/noncalcific tissues. Apo(a), apoB, apoC-III, apoE, and apoJ localized within the disease-prone fibrosa and colocalized with calcific regions as detected by immunohistochemistry. Circulating apoC-III on lipoprotein(a) is a potential biomarker of aortic stenosis incidence and progression, but whether apoC-III also induces aortic valve calcification is unknown. We found that apoC-III was increased in fibrotic and calcific tissues and observed within the calcification-prone fibrosa layer as well as around calcification. In addition, we showed that apoC-III induced calcification in primary human valvular cell cultures via a mitochondrial dysfunction/inflammation-mediated pathway. This study provides a first assessment of a broad array of apolipoproteins in CAVD tissues, demonstrates that specific apolipoproteins associate with valvular calcification, and implicates apoC-III as an active and modifiable driver of CAVD beyond its potential role as a biomarker.

Annexin A1-dependent tethering promotes extracellular vesicle aggregation revealed with single-extracellular vesicle analysis.

Extracellular vesicles (EVs) including plasma membrane-derived microvesicles and endosomal-derived exosomes aggregate by unknown mechanisms, forming microcalcifications that promote cardiovascular disease, the leading cause of death worldwide. Here, we show a framework for assessing cell-independent EV mechanisms in disease by suggesting that annexin A1 (ANXA1)-dependent tethering induces EV aggregation and microcalcification. We present single-EV microarray, a method to distinguish microvesicles from exosomes and assess heterogeneity at a single-EV level. Single-EV microarray and proteomics revealed increased ANXA1 primarily on aggregating and calcifying microvesicles. ANXA1 vesicle aggregation was suppressed by calcium chelation, altering pH, or ANXA1 neutralizing antibody. ANXA1 knockdown attenuated EV aggregation and microcalcification formation in human cardiovascular cells and acellular three-dimensional collagen hydrogels. Our findings explain why microcalcifications are more prone to form in vulnerable regions of plaque, regulating critical cardiovascular pathology, and likely extend to other EV-associated diseases, including autoimmune and neurodegenerative diseases and cancer.

Clinical characteristics, diagnosis, and risk stratification of pulmonary hypertension in severe tricuspid regurgitation and implications for transcatheter tricuspid valve repair.

AIMS: Patients with pulmonary hypertension (PHT) are often excluded from surgical therapies for tricuspid regurgitation (TR). Transcatheter tricuspid valve repair (TTVR) with the MitraClip™ technique is a novel treatment option for these patients. We aimed to assess the role of PHT in severe TR and its implications for TTVR. METHODS AND RESULTS: A total of 243 patients underwent TTVR at two centres. One hundred twenty-one patients were grouped as iPHT+ [invasive systolic pulmonary artery pressures (PAPs) ≥50 mmHg]. Patients were similarly stratified according to echocardiographic PAPs (ePHT). The occurrence of the combined clinical endpoint (death, heart failure hospitalization, and reintervention) was investigated during a follow-up of 330 (interquartile range 175-402) days. iPHT+ patients were at higher preoperative risk (P < 0.01), had more severe symptoms (P = 0.01), higher N-terminal pro-B-type natriuretic peptide levels (P < 0.01), more impaired right ventricular (RV) function (P < 0.01), and afterload corrected RV function (P < 0.01). Procedural TTVR success was similar in iPHT+ and iPHT- patients (84 vs. 84%, P = 0.99). The echocardiographic diagnostic accuracy to detect iPHT was only 55%. During follow-up, 35% of patients reached the combined clinical endpoint. The discordant diagnosis of iPHT+/ePHT- carried the highest risk for the combined clinical endpoint [HR 3.76 (CI 2.25-6.37), P < 0.01], while iPHT+/ePHT+ patients had a similar survival-free time from the combined endpoint compared to iPHT- patients (P = 0.48). In patients with isolated tricuspid procedure (n = 131) a discordant iPHT+/ePHT- diagnosis and an impaired afterload corrected RV function (P < 0.01 for both) were independent predictors for the occurrence of the combined endpoint. CONCLUSION: The discordant echocardiographic and invasive diagnosis of PHT in severe TR predicts outcomes after TTVR.

Treatment of failed aortic bioprostheses: An evaluation of conventional redo surgery and transfemoral transcatheter aortic valve-in-valve implantation.

BACKGROUND: The use of bioprostheses for surgical aortic valve replacement increased substantially within the last years. In case of prosthesis failure, re-SAVR is standard of care, whereas valve-in-valve deployment of a transfemoral transcatheter aortic valve prosthesis (VinV-TFAVI) has recently emerged as an alternative. We sought to evaluate early safety, clinical efficacy, and all-cause 1-year-mortality of VinV-TFAVI and redo surgery for failing aortic bioprostheses (re-SAVR). METHODS AND RESULTS: Patients receiving either VinV-TFAVI (n = 147) or re-SAVR (n = 111) for a degenerated aortic bioprosthesis between 01/2006 and 05/2017 were included in this analysis. All-cause 1-year mortality was the primary outcome measure. Early safety and clinical efficacy according to VARC-2 endpoint definitions were evaluated at 30 days. Baseline characteristics differed significantly between both groups including age, STS-PROM, and incidence of relevant comorbidities. Re-stenosis was the predominant mode of failure in 45.9% of re-SAVR and 63.1% of VinV-TFAVI patients. The rate of "early safety" endpoints was lower with VinV-TFAVI (17.7% vs. 64.9%, p < 0.01), the rate of "clinical efficacy" endpoints was lower, e.g. better with re-SAVR (53.1% vs. 32.4%, p < 0.01). All-cause 1-year-mortality (VinV-TFAVI 8.8% vs re-SAVR 9.9%, p = 0.84) was not different. Treatment strategy was not associated with 1-year-mortality in a Cox regression analysis. The incidence of prosthesis-patient-mismatch was higher in VinV-TFAVI compared to re-SAVR. CONCLUSION: VinV-TFAVI represents a viable alternative for treatment of degenerated aortic bioprostheses in patients at increased surgical risk. However, in patients at low risk for reoperation, a better clinical efficacy and acceptable safety may favour re-SAVR.