Pressure Overload Research Articles

Assessment of experimental circulating biomarkers in volume and pressure overload: insights from a cohort study

Abstract Introduction Experimental biomarkers including Angiopoietin-2 (ANG2), bone morphogenetic protein 10 (BMP10), fibroblast growth factor 23 (FGF23), and insulin-like growth factor-binding protein 7 (IGFBP7) are hypothesized to reflect cardiac pathophysiological processes that are potentially present in adverse cardiac remodeling in volume or pressure overload. This study aims to elucidate the relationship between these circulating biomarkers and the presence of hemodynamically significant pressure or volume overload and adverse outcomes and compare it to N-terminal pro B-type natriuretic peptide (NT-proBNP). Methods We studied the association between the four experimental circulating biomarkers in patients with pressure or volume overload with reference to none/mild valvular disease in N=1302 of an observational outpatient cardiology cohort. The median age was 63.0 (25th/75th quartile 51.5, 71.4) years, 445 (34.2%) were women. Circulating biomarkers were quantified using a novel antibody-based method. Logistic regression models with cox regression plots were employed to assess the association of each biomarker with the severity of valve disease concerning volume or pressure overload, adjusted for age and sex. Results In the overall population, elevated levels of ANG2, BMP10, FGF23 and IGFB7 were positively associated with the presence of significant volume overload (ANG2: Odds ratio (OR) 1.26 (95% confidence interval (CI) 1.17-1.35), p<0.001; BMP10: OR 2.57 (CI 1.89-3.48), p<0.001; FGF23: OR 1.51 (CI 1.14-1.20), p=0.004; IGFBP7: OR 1.39 (CI 1.14-1.69), p=0.001, NT-proBNP: OR 1.69 (CI 1.47-1.95), p<0.001). No statistically significant association between circulating biomarkers and pressure overload was observed. Over a median follow-up of 4 years, 31 (20.1%) participants died in the group of volume overload and 9 (40.9%) individuals in the group of pressure overload. After multivariable-adjustment, elevated levels of BMP 10 showed a borderline association with an increased risk of all-cause mortality in individuals with volume overload compared to none/mild valvular disease: hazard ratio (HR) 1.51 (CI 0.96- 2.38), p=0.075. Higher concentrations of all biomarkers were predictive of all-cause mortality for both individuals with volume overload and those with none/mild valvular disease (ANG2: HR 3.72 (CI 1.67-8.33), p=0.001; BMP10: HR 1.65 (CI 1.20-2.26), p=0.002; FGF23: HR 2.08 (CI 1.65-2.62), p<0.001; IGFBP7: HR 1.55 (CI 1.25-1.91), p<0.001; NT-proBNP: HR 1.72 (CI 1.47-2.00), p<0.001). Conclusions This study demonstrates that circulating biomarkers involved in distinct pathophysiological pathways of inflammation, fibrosis and calcification are elevated in patients with hemodynamically significant volume overload. Since they are also related to mortality, their clinical role needs to be explored further, also in context with the routine biomarker NT-proBNP.

Cardiac secreted-HSP90alpha in cardiomyocyte hypertrophy by N-Cadherin mediated signaling under pressure overload

Abstract Background Left ventricular hypertrophy (LVH) in response to pressure overload is strongly associated with adverse cardiovascular outcomes. Heat shock protein 90 (HSP90) has been reported to be involved in cardiac remodeling under stress. Aims Here, we evaluate whether serum HSP90α (an isoform of HSP90) increases and associates with cardiac hypertrophy in patients with hypertension or severe aortic stenosis (AS), and explore the potential mechanisms in experimental pressure overload mouse model. Methods Serum HSP90α levels in patients with hypertension or aortic stenosis (AS) were determined by ELISA. Pressure overload mouse model was built by a transverse aortic constriction (TAC). Cardiac function was assessed by echocardiography. Cardiac hypertrophy was examined by histology, western blot and RNA analysis. Results Serum levels of HSP90α were higher in patients with hypertension or AS than in the control group, respectively, and the levels positively correlated with LVH. HSP90α levels also increased in heart tissues of patients with obstructive hypertrophic cardiomyopathy (HCM), and mice after TAC, in parallel with the hypertrophic markers. TAC induced the enhanced expression and secretion of HSP90α from cardiomyocytes and cardiac fibroblasts. Knockdown of HSP90α or blockade of extracellular HSP90α (eHSP90α) prevent the development of LVH under pressure overload in vivo and in vitro. By Nano-HPLC-MS/MS analysis, we identified eHSP90α interacted with N-cadherin in cardiomyocyte surface, which induced the activation of β-catenin and promoted β-catenin to bind TCF7 (a member of TCF/Lef family) in nucleus, enhanced the transcription of hypertrophic genes, contributing to cardiac hypertrophy and dysfunction under pressure overload. Conclusions Our data demonstrated that cardiac secreted-HSP90α promoted myocardial hypertrophy by N-Cadherin mediated β-catenin/TCF7 signaling under pressure overload. It indicates the therapeutic potential of targeting HSP90α-initiated signaling against cardiac hypertrophy and dysfunction under pressure overload.

Deletion of mitochondrial DNA methyltransferase 1 contributes the development of murine heart failure under pressure overloaded

Abstract Background Mitochondrial DNA (mitDNA) has similarities to bacterial DNA, which contains inflammatogenic unmethylated CpG motifs. We found that mitDNA that escapes from autophagy causes inflammatory response and heart failure under pressure overload. DNA methyltransferase 1 (DNMT1) maintains methylation patterns in somatic cells. Deletion of DNMT1 results in embryonic lethality in mice and mitotic catastrophe in cultured cells. Additional possible translational start sites (ATG1, ATG2) are located upstream of the commonly accepted nuclear DNMT1 translational start site (ATG3) and there is a conserved mitochondrial translocation signal sequence between ATG1 and ATG3. The role of mitochondrial DNMT1 in the development of heart failure remains to be elucidated. Purpose The purpose of this study is to examine the in vivo role of mitochondrial DNMT1 in the heart under pressure overload. Methods We generated HA-tagged DNMT1 constructs, 1) starting from ATG1 (termed as whole) 2) from ATG3 (nuclear) and 3) from ATG3 and mutated in the nuclear translocation sequence (mitochondrial) and transfected HEK293 cells with the constructs. Localization of HA-tagged proteins was assessed by immunocytochemistry. We also generated mitochondrial DNMT1-deficient mice by inserting mutations into the ATG1 and ATG2. The mice were subjected to pressure overload by means of transverse aortic constriction (TAC) to induce heart failure. Cardiac remodelling was assessed by echocardiography as well as histological analyses 4 weeks after operation. Results Whole, nuclear and mitochondrial DMNT1 translocated to both mitochondria and nuclei, only nucleus and only mitochondria, respectively. Mitochondrial DNMT1-deficient mice were born at Mendelian frequency and grew to adulthood. Those showed no cardiac phenotypes under baseline conditions. However, the mice exhibited severe systolic dysfunction, indicated by left ventricular fractional shortening, 2 weeks after surgery compared with control littermates (control littermates 47.9% versus Mitochondrial DNMT1-deficient mice 32.3%, p<0.05). Intermuscular cell infiltration was observed in TAC-operated mitochondrial DNMT1-deficient hearts. Conclusions Mitochondrial DNA methyltransferase 1 plays a protective role in failing hearts and mitDNA methylation might be a therapeutic target to treat patients with heart failure.

Temporal dynamics of cardiac remodelling in pressure overload: the key role of visceral adipose tissue

Abstract Background Myocardial fibrosis is a prominent pathological feature of cardiac remodelling in pressure overload. The underlying mechanisms of cardiac remodelling are complex including mechanical, inflammatory and neurohormonal factors. We have recently uncovered a pathological crosstalk between visceral adipose tissue (VAT) and heart in biological aging characterized by profibrotic proteins in both the VAT secretome and the plasma contributing to myocardial interstitial fibrosis. We hypothesize that a model of pressure overload induced by transverse aortic constriction (TAC) is responsible for VAT remodelling and a VAT profibrotic secretome, which in turn worsens cardiac fibrosis and alters cardiac function. Purpose To explore the effect of pressure overload on VAT and identify a crosstalk between heart and VAT. Methods We divided wild-type male mice (5-month-old, n=10/group) into two groups: a visceral Lipectomy group and a Sham group two weeks before a moderate TAC (26G; i.e. gradient between left ventricle and aorta of 30mmHg) or a sham surgery. We sacrificed the mice at 1- and 8-week after TAC. We performed in vivo metabolic tests, echocardiography, and invasive hemodynamics, followed by ex vivo tissue analysis. We then analysed the time-course of the cardiac transcriptomic signature in TAC vs control and the impact of visceral lipectomy in both groups. Results Our results show that TAC induced not only cardiac remodelling affecting the structure and function of the heart, but also VAT fibrosis and inflammation together with activation of adrenergic receptors (Adrb3). VAT became a major source of profibrotic (TGFb and osteopontin) and proinflammatory (TNFa, IL6 and PAI1) factors as early as 1 week after TAC. Interestingly, lipectomy prevented cardiac remodelling and dysfunction. After 1 week of TAC, cardiac transcriptomic profile showed a similar upregulation of profibrotic and prohypertrophic genes in TAC groups in presence or absence of lipectomy. After 8 weeks of TAC, lipectomy prevented the upregulation of those genes and transcriptomic profile of TAC+lipectomy was similar to sham group (Figure). PCR analysis confirmed the lower expression of profibrotic (TGFb, Osteopontin), prohypertrophic (Nppa) and contractility genes (Adr1b) in TAC+Lipectomy vs TAC group after 8 weeks of TAC. Conclusion Our results suggest that VAT is detrimental to cardiac structure and function by releasing a profibrotic and a proinflammatory secretome that aggravates the cardiac remodelling induced by TAC. Conversely, lipectomy prevents the early development of TAC-induced cardiac fibrosis.

ATM: a protein involved in glucose and lipid metabolism in the heart

Abstract Backround Post-mitotic cells, such as neurons and cardiomyocytes, cannot repair DNA lesions with DNA replication and rely for their survival on efficient sensors and effectors that orchestrate the DNA damage response (DDR). The Ataxia Telangiectasia Mutated (ATM) protein kinase is the most important sensor of oxidative stress and the DNA damage response (DDR) and is implicated in cellular metabolism. It is believed that while transient DNA damage and DDR can temporarily improve cardiovascular function, persistent activation of DDR (and ATM) might promote the onset and development of heart failure (HF). Purpose We hypothesised that ATM might control and regulate energy metabolism in the heart under stress to promote DNA repair. Methods We analyzed the effects of ATM inactivation on cardiomyocyte hypertrophy, cardiac function, DDR and metabolism in hearts from wild-type (Atm+/+) or Atm-mutated (Atm-/-) mice under sham conditions or after pressure overload by transverse aortic constriction (TAC). Results ATM inactivation in Atm-/- mice induced cardiomyocyte hypertrophy, fetal gene expression re-activation and a specific metabolomic signature in the heart, characterized by significant accumulation of pyruvate, branched chain amino-acids, short-medium acyl-carnitines and metabolites of tricarboxylic acid cycle. The levels of the glycolytic enzymes, hexokinase-2 (HK2) and phosphofructokinase (PFK), were elevated. pyruvate was trapped in the cytosol because mitochondrial carriers were suppressed and the enzymes that process pyruvate were dysregulated. Because of pyruvate metabolic block, fatty acids oxidation was inefficient and resulted in the accumulation of acyl-carnitines and insulin resistance. These metabolic changes were amplified by TAC, which rapidly induced heart failure in Atm-/- mice. ATM inactivation also increased basal and TAC-induced genomic stress in cardiomyocytes, as shown by the levels of p-γ-H2AX, 8-oxodG glycosylase (OGG1/2) and apurinic site nuclease (APE1). These results prove that ATM rewires the metabolism of cardiac cells by inducing glycolysis and fatty acids oxidation. ATM stimulates glycolysis to repair DNA lesions and protect the heart against stress-induced dysfunction. The metabolic block due to ATM inactivation accelerates heart failure. Conclusions Our data suggest that ATM favors the metabolic flexibility of the heart by stimulating glucose entry and balancing glucose catabolism with fatty acid oxidation, thus preventing mechanical stress-induced cardiac systolic dysfunction.

Left ventricular dilatation in patients with significant aortic regurgitation: association with mortality

Abstract Background In aortic regurgitation (AR), left ventricular (LV) dilatation occurs as a response to volume and pressure overload. Current guidelines recommend the use of LV end-systolic diameter index (LVESDi) to give indication for intervention, but recent studies suggested that volumetric measures may be more accurate in identifying LV remodeling in AR as compared to linear dimensions. Purpose To characterize LV dilatation in patients with significant AR (≥moderate), based on linear and volumetric dimensions, and to determine their prognostic value. Methods A total of 1070 patients (56 ± 18 years,65% male) were included. Cut-off values of 20 mm/m2 for LVESDi and 45 ml/m2 for end-systolic volume index (LVESVi) were used to identify the following LV remodeling patterns: No-significant LV dilatation (N=485), when both LVESDi and LVESVi were below the cut-off values; Discordant LV dilatation (N=279) if only one positive criterion was present; and Concordant LV dilatation (N=306) when both LVESDi and LVESVi were enlarged (Figure 1). The primary endpoint was all-cause mortality. Results Baseline characteristics differed across the 3 LV dilatation groups. Compared to patients with no-significant or discordant LV dilatation, those with concordant LV dilatation were more likely to be men, had a lower prevalence of systemic arterial hypertension and were more symptomatic. Concerning the echocardiographic characteristics, patients with concordant LV dilatation showed more severe AR, worse LV systolic function and larger left atrial volumes compared to the other two LV dilatation groups. During a median follow-up of 89 (IQR,54-132) months, 168 (16%) patients died and 484 (45%) underwent aortic valve surgery (AVS). Patients with concordant LV dilatation had worse 10-year survival (72%) compared to the groups (Figure 2), but benefited more from AVS based on a landmark analysis (p=0.001). In multivariable analysis, a significant association with the risk of all-cause mortality was observed for the presence of discordant (HR 1.645, 95%CI 1.077-2.513;p=0.021) or concordant LV dilatation (HR 2.695, 95% CI 1.710 to 4.249;p<0.001) after adjusting for the variables significant in the univariate analysis such as, age, male gender, NYHA class III-IV, AVS as a time-dependent covariate and LV ejection fraction (LVEF) ≤55%. Moreover, the addition of LV dilatation groups to a basal model including the above mentioned clinical and echocardiographic variables led to a significant increase in the predictivity of the model (Chi-square difference=21.1,p<0.001). Conclusion In patients with significant AR, LV dilatation detected by linear and/or volumetric measures was independently associated with increased mortality. Combining both methods for assessment of LV remodeling may improve risk stratification of these patients.

Interleukin-22 inhibits right ventricular remodelling by a unique mechanism in a pulmonary artery constriction model

Abstract Background Fibrosis and remodeling of right ventricle (RV) are associated with prognosis in patients with RV failure. Interleukin-22 (IL-22) is a member of the IL-10 cytokine family, play roles in tissue protection and wound repair. We have previously shown that IL-22 plays an important role in cardiac remodeling after acute myocardial infarction; however, the role of IL-22 in RV fibrosis and remodeling remains elusive. Purpose We investigated the role of IL-22 in the pathogenesis of RV remodeling during pressure overload. Methods Pulmonary artery banding (PAB) is performed by placing a 6-0 suture around the pulmonary artery over a 24 G needle in wild type mice (C57BL/6J) and IL-22 knockout mice (IL-22 KO). Only mice with moderate pulmonary artery stenosis (peak pressure gradient across the pulmonary band: 25–40 mmHg at 1 week after surgery by echo Doppler) were included in the study protocol. Four weeks after PAB, RV function was measured by echocardiography and real-time PCR analysis was performed to measure Col1a1, Col3a1, BNP, and transcriptome analysis was performed. Survival confirmation of mice with moderate pulmonary artery stenosis was also performed up to 56 days. Results IL-22 KO mice had significantly higher 56-day mortality rate compared with WT mice after PAC (p<0.01). Four weeks after PAB, IL-22 KO mice showed markedly increased RV weight (IL-22 KO mice vs. wild-type mice; RV/LV+IVS: 0.48±0.05 vs 0.40±0.02, P=0.002). IL-22 KO mice exhibited significant RV enlargement and RV dysfunction 4 weeks after PAB. (IL-22 KO mice vs wild type mice; RVEDV: 10±2.3mm2 vs 12.9±3.1mm2, P=0.005, TAPSE: 10.8±1.8mm vs 9.5±1.7mm, P=0.04, FAC: 35.2±7.8% vs 23±6.0%, P<0.001). The expressions of Col1a1 and Col3a1 were no difference between in IL22-KO mice and Wild mice. However, BNP, a cardioprotective marker, tended to be lower in IL-22KO mice. The transcriptome analysis also showed that the group of fibrosis-related genes that are elevated in PAC in WT mice were less elevated in IL-22 KO mice. Conclusion These results suggest that IL-22 is involved in RV remodelling during RV pressure loading without a general mechanism.

CILP1 and NTproBNP in pulmonary hypertension and right ventricular pressure overload: a translational experimental study

Abstract Introduction Cartilage intermediate layer protein 1 (CILP1) has emerged as a novel marker of right ventricular (RV) dysfunction in pulmonary hypertension (PH), although there is still little evidence on its role in different scenarios of RV pressure overload. The aim of our study was to analyze CILP1 as a biomarker of RV remodeling and PH severity, and compare it with N-terminal pro-brain natriuretic peptide (NTproBNP), in different experimental models of RV pressure overload. Methods Three different experimental models of RV pressure overload compared to a sham procedure were evaluated in 24 Yucatan pigs: chronic postcapillary PH by pulmonary vein banding (M1, n=6); chronic PH by aorto-pulmonary shunting (M2, n=6); RV pressure overload by PA banding (thus without PH) (M3, n=6); and sham procedure (M0, n=6). Animals were evaluated at 8 months after surgery by right heart catheterization, cardiac magnetic resonance (CMR), and blood/histological sampling. Levels of CILP1 and NTproBNP at the RV myocardium and blood were determined with dedicated ELISA and compared among groups by Wilcoxon test with Bonferroni correction. Associations between biomarkers and RV performance indices and pulmonary arterial pressure (PAP) were assessed with Spearman correlation test. Results M1 animals developed chronic postcapillary PH with normal left ventricular (LV) performance and RV maladaptive hypertrophy (RV fibrosis and systolic dysfunction). M2 animals developed chronic precapillary PH associated with LV dilatation and RV maladaptive hypertrophy. On contrast, M3-animals developed severe RV pressure overload (without PH) and hypertrophy but maintained normal RV systolic function. CILP1 and NTproBNP levels were moderately correlated (R=0.56, p=0.002). CILP1 levels in RV myocardium and plasma were significantly higher in M1, whereas NTproBNP plasma levels were significantly higher in M2 (Figure 1). CILP1 in plasma and RV myocardium significantly correlated with PAP, while myocardial CILP1 levels also correlated with RV extracellular volume (RV-ECV) by CMR (Figure 2). NTproBNP myocardial levels correlated with RV ejection fraction and RV-ECV and plasmatic levels correlated with PAP (Figure 2). Conclusions CILP1 levels were increased in the presence of PH and isolated RV dysfunction, whereas NTproBNP levels were increased in the model of PH, RV dysfunction and LV remodeling. Myocardial levels of both peptides correlated with diffuse fibrosis, estimated by CMR, whereas plasmatic levels of both biomarkers correlated with PAP. This suggests that CILP1 may be a more specific marker of RV dysfunction in PH, being less dependent of LV parameters.CILP1 and NTproBNP levels among modelsCorrelation with PAP & RV remodeling

Renal Semaphorin 3C mediates cardiac adaptive response

Abstract Cardiorenal syndrome, characterized by reciprocal heart-kidney interactions that progressively promote dysfunction in both organs, is associated with a high mortality rate. However, the mechanisms linking the two organs are insufficiently understood. Here we report that semaphorin 3C (SEMA3C) is a novel cardioprotective mediator secreted from the kidney. SEMA3C was highly expressed in the renal proximal tubules in mice. Renal Sema3c expression and circulating SEM3C were reduced by the left ventricular pressure overload that induced renal remodeling. Proximal tubule-specific secretory Sema3c deletion exacerbated cardiac hypertrophy, fibrosis and dysfunction after the pressure overload, suggesting renal SEMA3C is important for the proper cardiac adaptive response. Mechanistically, SEMA3C inhibits pathological cardiac remodeling at least partly by inhibiting Akt, ERK and Wnt/β-catenin signaling in cardiomyocytes. In heart failure patients, the plasma SEMA3C level was decreased and the low plasma SEMA3C was associated with poor cardiac outcomes. Collectively, our results show that SEMA3C produced by the kidney pivotally contributes to the cardiac stress response and its reduction contributes to the progression of heart failure. SEMA3C signaling appears to be an attractive therapeutic and diagnostic target for cardiorenal syndrome.

Vaccination targeting senescence-associated transmembrane protein alleviated cardiovascular pathology in the mice

Abstract Introduction Accumulation of senescent cells is observed in various organs including vasculature, heart and white adipose tissue with age, and known to become a substrate of pathophysiology of various cardiovascular-metabolic diseases. We have previously developed a vaccine to eliminate senescent cells, so-called "senolytic vaccine" by targeting Glycoprotein Nonmetastatic Melanoma Protein B (GPNMB) as a cellular-senescence-associated cell surface protein. We have demonstrated that GPNMB senolytic vaccine could remove senescent cells and alleviate the pathology cardiovascular-metabolic diseases. Senescence-associated adhesion molecule 1 (SAAM-1) is also known as a cell-surface membrane to increase its expression during cellular senescence in endothelial cells as well as the development of cardiovascular diseases. Here, we identified SAAM-1 as another senescence antigen and created a vaccine to eliminate senescent cells by targeting SAAM-1. Purpose This study was purposed to evaluate the efficacy of SAAM-1 vaccine for the treatment of cardiovascular diseases in mice models. Methods As a pressure overload-induced heart failure (HF) model, C57BL/6N wild type (WT) mice were underwent transverse aortic constriction (TAC) or sham opretaion at 13 weeks of age. SAAM-1 or control vaccination were given at 8 and 10 weeks of age before operation. Echocardiography examination was conducted two weeks after TAC operation, followed by tissue sampling 3 weeks after the examination. As an atherosclerosis model, ApoE KO mice were subjected to a high-fat diet (HFD) starting at 4 weeks of age. Vaccination of ApoE KO mice was administered at 8 weeks of age with SAAM-1-vaccine or control-vaccine, followed by sacrifice 4 weeks later for further analysis. ApoE-KO mice were also crossed with p16-mediated Luciferase expressing mice (p16-Luc mice) and subjected to generation of atherosclerosis model. Results SAAM-1 expression was significantly increased in left ventricle (LV) in TAC mice but its increase was suppressed by SAAM-1 vaccination. Interestingly, both worsening systolic function and dilatation of LV by pressure overload were significantly alleviated by SAAM-1 vaccination. Furthermore, expression level of senescent markers including p16 and p21, as well as several inflammation markers were increased in failing heart along with development of cardiac fibrosis, but SAAM-1 vaccine could significantly attenuate this pathological change. In ApoE KO mice, SAAM-1 vaccine decreased expression level of several inflammation markers in the mice, along with a decreasing p16 signal in the aorta. Conclusions Targeting SAAM-1 for vaccination would be a novel and promising approach to alleviating age-related cardiovascular disease.

Impact of right ventricular - pulmonary arterial coupling on mortality after transcatheter aortic valve implantation in patients with aortic stenosis

Abstract Background Aortic stenosis (AS) leads to left ventricle (LV) pressure overload. In more advanced stages of the disease, this pressure, which is transmitted through the pulmonary vasculature, may result in right ventricle (RV) remodeling and eventual dilatation and disfunction. RV failure is associated with impair prognosis, even after relief of the obstruction. The interplay of pulmonary arterial (PA) pressure and RV function can be assess using RV-PA coupling index; in a compensate state RV function is coupled with pulmonary pressure, and this function has a proper response to an increase in pulmonary afterload; in contrast, when RV function uncouples with pulmonary pressure it means that RV function can no longer sustain PA afterload, leading to a decompensate state. RV-PA uncoupling has already been associated with poor prognosis in other heart conditions, such as heart failure or pulmonary hypertension; however, there is still not much evidence on how RV-PA uncoupling prior transcatheter aortic valve implantation (TAVI) impacts on mortality. Purpose Assess the impact of RV-PA uncoupling on all-cause mortality after TAVI in patients with aortic stenosis. Methods In a prospective TAVI registry, patients were included if they had an adequate echocardiographic evaluation prior TAVI. All-cause mortality after the procedure was analyzed in two subgroups, according to their RV-PA coupling status. RV-PA was assess using tricuspid annular plane systolic excursion (TAPSE) and pulmonary arterial systolic pressure (PASP). The cut-off value was 0.39, consistent with other studies. Hazard ratios (HR) are calculated by univariate and multivariate Cox proportional hazard model. Multivariate adjustment included baseline characteristics – including age, gender, hypertension, diabetes, dyslipidemia, atrial fibrillation, and serum albumin –, and Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) and European System for Cardiac Operative Risk Evaluation (EUROSCORE) II. Results A total of 1190 patients underwent TAVI from January 2011 to December 2023; 315 patients were eligible, with mean age 82,24 years (± 8,0), 52% being women, and a mean EUROSCORE II score of 4.0 (± 9,3). The RV-PA cut-off value of 0.39 stratified patients into groups of RV-PA coupling (n = 194/63,6 %) or uncoupling (n = 121/38,4 %). During follow-up time (35,94 months ±25,6), patients with unpaired coupling had a 64% more risk of all-cause mortality in univariate analysis and, after adjusting for the parameters above, a 58% increased risk in multivariate analysis. Table. Conclusions Patients with significant aortic stenosis who had an impair RV-PA coupling prior TAVI had a significant increased risk of all-cause mortality. This suggests the need to incorporate this parameter to our right-side hemodynamics evaluation prior the procedure. Broader experience to determine its application and cut-off value are still needed.

Fenofibrate modulates cardiac energy metabolism in moderate-severe aortic stenosis: a mechanistic double-blinded randomised controlled MR trial

Abstract Background Aortic stenosis (AS) is associated with impaired cardiac metabolism and high-energy phosphate production which can further exacerbate the progression to HF. Myocardial lipid accumulation and reduced production of high-energy phosphates have important implications for both systolic and diastolic heart function in AS. Peroxisome proliferator-activated receptor alpha (PPAR-alpha agonist, has the potential to optimise cardiac substrate metabolism, thereby, may be effective in improving cardiac dysfunction and functional capacity in AS. Methods In this prospective, randomized, double-blind, placebo-controlled study, patients with moderate-to-severe asymptomatic AS (n=72) were randomly assigned to Fenofibrate 200 mg daily or matching placebo for 6 months in 4:1 fashion. Of the total 72 participants, 59 received Fenofibrate and 13 received placebo. All subjects underwent cardiac magnetic resonance (CMR) and exercise testing at 0 and 6 months, with follow-up data available in 47 patients. The primary end point was change in myocardial triglyceride content (MTG) determined by proton magnetic resonance spectroscopy (1H-MRS). Secondary outcome measures included change in cardiac energetics (PCr/ATP) determined by phosphorus magnetic resonance spectroscopy (31P-MRS), left ventricular strain determined by myocardial tagging and exercise capacity i.e. peak VO2 assessment via cardiopulmonary exercise testing. Results Cardiac energetics (PCr/ATP) showed statistically significant improvement in the Fenofibrate group (0.14 ± 0.48; CI: - 0.03, 0.30; p=0.05) vs placebo group (0.11 ± 0.75; CI -0.42, 0.65; p=0.64). There was also significant reduction in MTG in the Fenofibrate group (mean change -0.40 ± 0.97; 95% CI -0.74, -0.06; p=0.02). MTG content also reduced in the placebo group (mean change -0.41 ± 0.26, 95% CI -1.10, 0.18, p 0.13), but the reduction was not statistically significant. Though no significant changes were seen in the systolic function parameters, there was a significant improvement in diastolic function in the fenofibrate group only (peak diastolic longitudinal strain rate 9.6, 95% CI: 1.13, 18.1; p = 0.02). Peak VO2 did not show any significant improvement in either group. Conclusions Fenofibrate works as a metabolic modulator upregulating fatty acid metabolism in pressure overload AS hearts. Such modulation is associated with an improvement in cardiac energetics and diastolic function in moderate-severe AS.Main results from baseline to 6 monthsBaseline demographic and CMR parameters

The effect of afterload on right ventricular pacing-induced left ventricular dysfunction: a translational study

Abstract Introduction Right ventricular (RV) pacing (RVP) impairs left ventricular (LV) function. Nevertheless, the interaction between arterial afterload and RVP-associated LV dysfunction has not been investigated yet. Purpose We sought to examine the effect of afterload on RVP-evoked LV hemodynamic changes in patients with aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI) as well as in a small animal model of sustained LV pressure overload (PO). Methods Thirty-five patients with AS and a previously implanted pacemaker underwent detailed echocardiographic examination immediately before TAVI and also on the second postoperative day. The ultrasound measurements were carried out during intrinsic, narrow QRS rhythm and during frequency-matched RVP as well. Global myocardial work index (GMWI) was calculated to assess LV contractility. In parallel, LV pressure-volume analysis was performed in Wistar rats with transverse aortic constriction (TAC) or sham operation (Sham) during intrinsic narrow QRS rhythm (termed as TAC-Vsense and Sham-Vsense) as well as during RVP (termed as TAC-Vpace and Sham-Vpace). RVP was achieved in rats by an octopolar electrophysiology catheter placed in the RV. Results RVP decreased LV contractility in AS patients before and after TAVI as well. Nevertheless, the extent of RVP-evoked LV dysfunction was alleviated following pressure unloading (ΔGMWI: -37±7 vs. -25±8%, before TAVI vs. after TAVI, P<0.05). Similarly, although RVP was associated with reduced LV contractility in both the TAC (the slope of the maximum rate of LV pressure rise-end-diastolic volume relation [dPdtmax-EDV]: 92±8 vs. 53±6mmHg/s/µl, TAC-Vsense vs. TAC-Vpace; P<0.05) and Sham groups (dPdtmax-EDV: 74±5 vs. 60±9 mmHg/s/µl, Sham-Vsense vs. Sham-Vpace; P<0.05), the negative inotropic effect of RVP was found to be stronger in the TAC compared to the Sham group (ΔdPdtmax-EDV: -42±4 vs. -19±6%; TAC vs. Sham, P<0.01). Furthermore, reduction of the maximal rate of LV pressure decrease (ΔdPdtmin: -20±3 vs. -5±5%, TAC vs. Sham, P<0.01) and prolongation of the active relaxation time constant (Δτ: 22±3 vs. 6±3%, TAC vs. Sham, P<0.01) also occurred to a greater extent in case of sustained LV PO, indicating augmented diastolic dysfunction. Conclusion Our translational results indicate that RVP-induced LV dysfunction might be afterload dependent.

Role of CT-derived global longitudinal strain in identifying left ventricular dysfunction in patients with severe aortic stenosis and preserved left ventricular ejection fraction

Abstract Introduction In patients with severe aortic stenosis, LVEF <50% is a current class 1 indication for aortic valve replacement. There are however studies showing increased mortality in patients with asymptomatic severe aortic stenosis and LVEF between 50-59% [1, 2]. Global longitudinal strain (GLS) has emerged as a more sensitive predictor of systolic dysfunction than ejection fraction in a wide number of cardiac diseases [3]. Purpose The aim of our study was to analyze left ventricular global longitudinal strain (GLS) by cardiac computed tomography (CT) in patients with severe aortic stenosis. We hypothesized that a larger portion of patients with LVEF 50-59% have signs of systolic dysfunction by GLS as compared to patients with LVEF ≥60%. Methods We identified 238 patients (median age 81, 51.3% females) with severe aortic stenosis, assessed by cardiac CT before undergoing transcatheter aortic valve replacement at Uppsala University hospital between 2016-2019. Patients in atrial fibrillation was excluded due to suboptimal image quality. Left ventricular mass index (LVMi), EF and peak GLS were calculated. The patients were divided into three groups based on LVEF (Reduced LVEF <50%, Low-Normal LVEF 50-59% and Normal LVEF ≥60%) and compared with each other regarding GLS, biomarkers and background variables. The cut off for significantly reduced GLS was set at <16%, in accordance with recently proposed criteria [4]. Results As expected GLS was significantly reduced in all patients with LVEF <50%. Among patients with Low-Normal LVEF, 62.3% had significantly reduced GLS as compared to only 3.8% patients with Normal LVEF >60% (p < 0.001). Median GLS in Low-Normal LVEF was 15.5% (IQR 14.1 - 17.4) as compared to 20.2% (IQR 18.4 - 21.9) in Normal LVEF (p < 0.001). Patients with Low-Normal LVEF had a significantly higher LV mass as compared to patients with Normal LVEF (median LVMi 85.8 g/m² vs. 75.8 g/m², p < 0.001). NT-pro-BNP was significantly higher in patients with Low-Normal LVEF compared to Normal LVEF (median 1130 vs. 664 ng/l, p = 0.003). Conclusions Almost two third of patients with severe aortic stenosis and lower range of normal LVEF (50-59%) had abnormally reduced GLS, reflecting systolic LV dysfunction, which was uncommon among those with LVEF >60%. Patients with LVEF 50-59% also presented with higher LV mass index and higher levels of NT-pro-BNP than patients with normal LVEF >60%, reflecting hypertrophic response of the myocardium to pressure overload which over time may lead to progressive myocardial decompensation. LVEF in the range of 50-59% might be an early sign of LV decompensation in severe aortic stenosis.

RKER-012, a novel modified ActRIIB ligand trap, attenuated right ventricular cardiomyopathy in a preclinical model of pulmonary arterial hypertension

Abstract Background The primary cause of death in pulmonary arterial hypertension (PAH) is right ventricular (RV) failure. Initially, the RV adapts to heightened pressure through adaptive remodeling, but prolonged pressure overload triggers maladaptive remodeling, culminating in failure. Overactive activin/growth differentiation factor (GDF) signaling has been implicated in cardiomyopathy and heart failure. RKER-012, a research version of KER-012, is an investigational modified activin receptor type IIB (ActRIIB) ligand trap designed to specifically bind and inhibit select TGF-β ligands, including activins A and B and GDFs 8 and 11. RKER-012 previously exhibited a cardioprotective effect in a pulmonary arterial banding (PAB) model of RV dysfunction. To determine the effect of RKER-012 on afterload-induced RV cardiomyopathy caused by increased pulmonary artery pressure, we utilized an angio-obliterative Sugen/hypoxia (SH) rat model of PAH that closely mimics human PAH pathology. Methods Male Sprague Dawley rats were subcutaneously (s.c.) injected with one dose of Sugen 5416 and exposed to 10% hypoxia for 3 weeks during which they received either vehicle (SH-Veh; s.c; BIW) or RKER-012 (10 mg/kg; s.c; BIW). Normoxic (Nx) control rats were maintained in room air for 3 weeks with BIW s.c. vehicle treatment. After 3 weeks of treatment, systolic pulmonary arterial pressure (sPAP) and Fulton index (FI) were assessed. Hallmark genes of inflammatory process, endothelial/platelet activation, and fibrosis were evaluated in the RV by qPCR. Results Increases in FI (+99.4%;p<0.0001) and sPAP (+250.9%;p<0.0001) were observed in SH-Veh rats vs. Nx rats, consistent with the development of pulmonary and cardiac impairment. In contrast, treatment with RKER-012 reduced FI (-28.0%;p<0.001) and sPAP (-44.5%;p<0.001). In the RV, SH-Veh rats had increased expression of TGF-ß pathway genes involved in inflammation, endothelial/platelet activation, and fibrosis. RKER-012 treatment reduced expression of these genes (Tgf-β1, -44.7%;p=0.003; Fstl3, -43.5%;p=0.0162; Mcp1, -22.5%;p=0.535; Cd68, -60.3%;p=0.0048; Ctgf, -57.1%;p=0.0139; Col1a1, -47.2%, p=0.0255 ;Col3a1, -69.5%;p<0.0001; Lox, -61.4%;p=0.0054; P-selectin, -63.9%;p=0.018) in comparison to SH-Veh treatment. Conclusion Consistent with previous findings in a PAB mouse model, RKER-012 treatment protected against increased sPAP and maladaptive cardiac remodeling in a SH rat model of PAH. Additionally, RKER-012 attenuated RV cardiomyopathy by reducing the expression of genes involved in inflammatory and fibrotic processes. These preclinical findings in the RV paralleled the changes in circulating cardiovascular health biomarkers, including reduced NT-proBNP, observed in a Phase 1 trial of KER-012 in healthy volunteers. These findings, along with the safety and tolerability observed in the Phase 1 trial, provided rationale for the ongoing Phase 2 TROPOS trial of KER-012 in patients with PAH (NCT05975905).

Myocardial work and aortic valve stenosis cardiac damage stages are predictors of all-cause mortality in patients undergoing transcatheter aortic valve replacement

Abstract In aortic stenosis (AS) patients, assessment of left ventricular (LV) systolic function is complicated due to the significant impact of increased afterload on conventional parameters. Myocardial work (MW) analysis, a novel echocardiographic method adjusts myocardial deformation to instantaneous LV pressure which may better reflect the LV contractile state. Importantly, long-term LV pressure overload has marked backward effects beyond the LV: classification of this extravalvular cardiac damage effectively represents the involvement of the cardiopulmonary system in AS. Both MW and cardiac damage staging could hold remarkable prognostic power in the clinically complex population of transcatheter aortic valve replacement (TAVR) candidates. Accordingly, our aim was to assess the prognostic value of MW analysis and cardiac damage staging in patients undergoing TAVR. We enrolled 289 patients (79±6 years, 41% female) prior to TAVR. Echocardiographic measurements were performed one day before the procedure. We calculated LV ejection fraction (EF) and by speckle-tracking echocardiography global longitudinal strain (GLS), as well. Global constructive work (GCW) was quantified with dedicated software and LV pressure was estimated using transaortic mean gradient and systolic blood pressure. Based on the echocardiographic data, we also determined the extent of cardiac damage associated with AS: patients were classified as Stage 0 (no cardiac damage), Stage 1 (LV damage), Stage 2 (mitral valve or left atrial damage), Stage 3 (pulmonary artery vasculature or tricuspid valve damage), or Stage 4 (right ventricular damage). Our primary outcome was all-cause mortality, reached by 68 patients (median follow-up: 26 months). In our cohort, preprocedural EF was 47±13 %, GLS was -12.3±4 %, while GCW was 2043±791 mmHg%. 14 (5%) patients were classified as Stage 0, 61 (21%) as Stage 1, 128 (44%) as Stage 2, 15 (5%) as Stage 3, and 71 (25%) as Stage 4. GCW showed a continuous decline through the AS Stages (from Stage 0-4: 2963±652 vs. 2154±652 vs. 2168±718 vs. 1988±969 vs. 1552±772 mmHg%; p<0.001). Using univariate Cox analysis GCW (HR 0.968 [95% CI 0.938-0.998] per 100 unit change; p=0.034) and AS Staging (HR 1.236 [95% CI 1.015-1.505]; p=0.035) were both associated with all-cause mortality, while EF (HR 0.984 [95% CI 0.966-1.002]; p=0.085) and GLS (HR 1.042 [95% CI 0.984-1.103]; p=0.160) were not. In multivariate Cox regression models, both GCW (HR 0.957 [95% CI 0.922-0.992] per 100 unit change; p=0.018) and AS cardiac damage staging (HR 1.263 [95% CI 1.029-1.549]; p=0.025) were proven to be significant independent predictors of all-cause mortality. In TAVR patients, preoperative GCW values exhibited a persistent decrease across AS Stages. As opposed to EF and GLS, GCW and AS Staging both showed strong association with all-cause mortality in our cohort. Moreover, GCW had higher prognostic value than any other conventional or advanced measure of LV function.

Subendocardial ischemic-like state in patients with severe aortic stenosis: insights from myocardial histopathology and ultrastructure

Abstract Background myocardial adaptation to severe aortic stenosis (AS) is a complex process that involves myocardial fibrosis (MF) beyond cardiomyocyte hypertrophy. Perfusion impairment is believed to be involved in myocardial remodeling in chronic pressure overload. Aim to describe morphological and ultrastructural myocardial changes at EMB, possibly reflecting subendocardial ischemia, in a group of patients with severe AS referred to surgical aortic valve replacement (AVR), with no previous history of ischemic cardiomyopathy. Methods one-hundred-fifty-eight patients (73 [68-77] years, 50% women) referred for surgical AVR because of severe symptomatic AS with pre-operative clinical and imaging study and no previous history of ischemic cardiomyopathy. Intra-operative septal EMB was obtained in 129 patients. Tissue sections were stained with Masson ́s Trichrome for MF quantification and periodic acid-Schiff (PAS) staining was performed to assess the presence of intracellular glycogen. Ultrastructure was analyzed through Transmission electron microscopy (TEM). Results MF totalized a median fraction of 11.90% [6.54-19.97%] of EMB, with highly prevalent perivascular involvement (95.3%). None of the samples had histological evidence of myocardial infarction. In 58 patients (45%) we found subendocardial groups of cardiomyocytes with cytoplasmatic enlargement, vacuolization and myofiber derangement, surrounded by extensive interstitial fibrosis. These cardiomyocytes were PAS positive, PAS-diastase resistant and Alcian Blue/PAS indicative of the presence of neutral intracellular glyco-saccharides. At TEM there were signs of cardiomyocyte degeneration with sarcomere disorganization and reduction, organelle rarefaction but no signs of intracellular specific accumulation. Conclusion almost half of the patients with severe AS referred for surgical AVR have histological and ultrastructural signs of subendocardial cardiomyocyte ischemic insult. It might be inferred that local perfusion imbalance contributes to myocardial remodeling and fibrosis in chronic pressure overload.

Prognostic value of left atrial strain in patients with moderate to severe mitral stenosis

Abstract Background Mitral stenosis causes an inflow restriction during diastole and is characterized by an increase in left atrial (LA) pressure with reduced cardiac output. Pressure overload of the LA can lead to atrial fibrosis and remodeling, resulting in a loss of LA reservoir and compliance capacity that can lead to backward load on the pulmonary circulation. To date, there are limited studies evaluating the impact of LA strain on prognosis of mitral stenosis patients. Purpose The aim of this study was to assess the prognostic value of LA strain in patients with moderate to severe mitral stenosis using two-dimensional (2D) strain imaging. Methods This was a single-center retrospective study, 237 patients with moderate or severe mitral stenosis were enrolled from January 2010 to December 2022. Baseline clinical and echocardiographic parameters were collected, LA strain measurements with reference time point at end diastole for reservoir strain (LASr), conduit strain (LAScd) and contraction strain (LASct) were analyzed using TOMTEC software. The endpoint was a composite outcome of all-cause mortality, heart failure hospitalization and valve intervention (percutaneous transvenous mitral commissurotomy and surgical intervention). All the LA parameters were analyzed separately to avoid collinearity. Results A total of 237 patients were included in the study. The patients had a mean age was 66.56 ± 13.61 years-old and were predominantly female (67.9%) with median follow up duration is 4.54 years (IQR 1.44 – 6.44). Mean left ventricular ejection fraction (LVEF) was 56.86 ± 10.51%, mean left atrium volume index (LAVI) was 73.94 ± 55.46 ml/m2, mean for LASr, LAScd and LASct were 11.81 ± 8.89%, -6.19 ± 4.50%, and -5.58 ± 6.05% respectively. LASr with a cut-off < 15.8% was independently associated with the composite outcome of all-cause mortality, heart failure hospitalization and valve intervention on multivariable Cox regression analysis (HR 2.51, 95% CI 1.54 - 4.10, p < 0.001). LAScd, LASct and LA volume index did not demonstrate any significant association with the endpoint. Conclusion LASr was independently associated with all-cause mortality, heart failure hospitalization and valve intervention in patients with moderate to severe mitral stenosis.

LV reverse remodeling after SAVR in patients with severe symptomatic aortic stenosis: impact on the clinical outcome

Abstract Introduction Surgical aortic valve replacement (SAVR) is the treatment of choice for young patients with severe aortic stenosis (AS) and low surgical risk. Left ventricular (LV) reverse remodeling (RR) after surgery is expected to occur. However, this is not always the case following afterload relief, and this may impact the prognosis. We aimed to assess the prognostic effect of distinct definitions of LV RR after SAVR in the long-term outcome of patients with severe AS. Methods Single-centre prospective study including patients referred for SAVR due to severe symptomatic AS, with no previous history of ischemic cardiomyopathy. Both pre- and post-operative transthoracic echocardiographic (TTE) and cardiac magnetic resonance (CMR) study (at the 3rd to 6th month after SAVR) were performed. LV RR was defined when in presence of at least one of the imaging criteria: >15% decrease in end-diastolic volume (EDV) by CMR; >15% decrease in LV indexed mass (LVM) by CMR; >10% decrease in geometric remodeling (LV mass/EDV ratio) by CMR; >10% increase in LV ejection fraction (LVEF) by CMR; >50% increase on global longitudinal strain (GLS) by TTE. We assess the prognostic value of RR definitions for the outcome after SAVR using Cox regression and Kaplan-Meier analysis. The primary endpoint was defined as all-cause mortality, heart failure (HF) hospitalization or worsening HF. Results We enrolled 140 patients – mean age 71±9 years-old, 49% male, predominantly high-gradient-normal flow AS (mean gradient 65±18mmHg, aortic valve area 0.7±0.2cm2, index stroke volume 47±11mL/m2) submitted to SAVR. At a mean follow-up (FUP) of 34±12 months, 23 (16%) patients met the primary endpoint: 4% (5 patients) died immediately after surgery; three patients died at the FUP (overall mortality rate of 6%). 12 patients (9%) were admitted for HF and 7 (5%) had at least one episode of worsening HF. 118 patients had complete pre and post-surgery imaging study (mean FUP: 36±10 months): 103 patients (87%) had at least one RR parameter (Table 1). Post-operative RR was not independently associated with the clinical outcome (Figure 1A). LVM was the sole independent predictor of the outcome at univariate analysis (Figure 1B–F). Conclusions LV RR after SAVR is highly prevalent in a cohort of patients with classical severe symptomatic AS. However, only LVM regression independently predicts the clinical outcome after surgery. This may stand the greater importance of structural reverse remodeling, rather than LV functional improvement, after pressure overload relief.

Aortic valve calcium score to mean gradient ratio: a new frontier in aortic stenosis prognostication

Abstract Introduction Aortic stenosis (AS) presents diagnostic challenges, especially in patients with discordant low gradient AS (LGAS), i.e., small aortic valve area (AVA) and low Doppler mean gradient (MG). LGAS is associated with worse outcomes compared to concordant AS. Aortic valve calcium score (AVCS) is a measure of AS severity independent of flow and helps diagnose severe AS. It is unknown if the degree of discordance in AVCS and MG is of any clinical significance. A high AVCS/MG ratio may indicate impaired ventricular function and response to pressure overload despite preserved LVEF, potentially contributing to worse outcomes. Purpose This study aims to elucidate the prognostic significance of the AVCS/MG ratio in patients with severe AS and preserved left ventricular ejection fraction (LVEF) undergoing TAVR. We hypothesized a higher AVCS/MG ratio correlates with increased mortality. Methods Patients who underwent transcatheter aortic valve replacement (TAVR) from 2010 to 2020 for native valve severe AS with LVEF≥50% were identified from an institutional database. AVCS were obtained within 90 days of pre-TAVR echocardiography. Patients were divided into tertiles based on their AVCS/MG ratio. Primary outcome was overall mortality. Results The analysis included 1067 patients (mean age 79±9 years, 43% female); overall AVA was 0.80±0.14 cm², LVEF 63±6%, MG 46±12 mmHg, AVCS 2630±1528 AU, and AVCS/MG ratio 58±31. Patients stratified by AVCS/MG tertiles showed no difference in overall comorbidity index across tertiles (Figure 1). However, the group in the highest tertile was the oldest (80±8 vs 79±8 vs 77±9 years), predominantly male (87% vs 61% vs 24%), with the highest prevalent atrial fibrillation (44% vs 28% vs 25%) and stroke volume index <35 mL/m² (16% vs 11% vs 5%). 9-year survival was 15% vs 25% vs 36% (p<0.001, Figure 2). In multivariate analysis adjusted for age, sex, comorbidities, LVEF and AVA, AVCS/MG ratio was independently associated with increased risk of mortality (HR 1.005; 95% CI [1.001-1.008], p=0.005). Conclusion Higher AVCS/MG discordance is associated with increased risk of mortality following TAVR. Serial AVCS measurements during progressive AS may help identify patients at higher risk who may potentially benefit from earlier aortic valve intervention.