Prognostic value of myocardial fibrosis in patients with severe aortic valve stenosis

Ventricular arrhythmias in patients with bicuspid aortic valves

INTRODUCTION

Bicuspid aortic valves (BAV) are the most common congenital heart defects and the extent of ventricular arrhythmias (VA) in patients with BAV is unclear. The objective of this study is to describe VAs and late gadolinium enhancement cardiac magnetic resonance imaging (LGE-CMR) in patients with BAV.

METHODS

A total of 19 patients with BAV (18 males, age: 58 ± 13 years) were referred for VA ablation procedures. Ten patients had BAVs at the time of ablation, nine patients had prior aortic valve replacement for a BAV. All but one patient had LGE-CMR and all patients underwent programmed ventricular stimulation at the time of the ablation.

RESULTS

Frequent PVCs were the targeted VAs in 17/19 patients and VT in 2/19 patients. Monomorphic ventricular tachycardia (VT) was inducible in 6 patients. A total of 15 VTs were inducible (2.5 ± 1.0 VTs per patient with a mean cycle length of 322 ± 83 msec). LGE was present in 13 patients. Patients with inducible VT had larger borderzone and core scar compared to non-inducible patients (7.8 ± 2.1 cm3 vs. 2.5 ± 3.1 cm3 and 5.1 ± 2.6 cm3 vs. 1.9 ± 3.0 cm3, p-value < .05 for both). PVCs and VTs were mapped to the periaortic valve area in 12 patients and 4 patients, respectively. The PVC burden was reduced from 27 ± 13 to 3 ± 6 (p < .001) and the ejection fraction improved from 49 ± 13% to 55 ± 9% (p = .005).

CONCLUSIONS

VAs in patients with BAV often originate from the perivalvular area and patients often have LGE and inducible VT. LGE may be due to ventricular remodeling secondary to the presence of BAV and harbors the arrhythmogenic substrate for VT.

The Significance of Parametric Mapping in Advanced Cardiac Imaging

Cardiac magnetic resonance imaging has witnessed a transformative shift with the integration of parametric mapping techniques, such as T1 and T2 mapping and extracellular volume fraction. These techniques play a crucial role in advancing our understanding of cardiac function and structure, providing unique insights into myocardial tissue properties. Native T1 mapping is particularly valuable, correlating with histopathological fibrosis and serving as a marker for various cardiac pathologies. Extracellular volume fraction, an early indicator of myocardial remodeling, predicts adverse outcomes in heart failure. Elevated T2 relaxation time in cardiac MRI indicates myocardial edema, enabling noninvasive and early detection in conditions like myocarditis. These techniques offer precise insights into myocardial properties, enhancing the accuracy of diagnosis and prognosis across a spectrum of cardiac conditions, including myocardial infarction, autoimmune diseases, myocarditis, and sarcoidosis. Emphasizing the significance of these techniques in myocardial tissue analysis, the review provides a comprehensive overview of their applications and contributions to our understanding of cardiac diseases.

Multi-modality imaging in aortic stenosis: an EACVI clinical consensus document

In this EACVI clinical scientific update, we will explore the current use of multi-modality imaging in the diagnosis, risk stratification, and follow-up of patients with aortic stenosis, with a particular focus on recent developments and future directions. Echocardiography is and will likely remain the key method of diagnosis and surveillance of aortic stenosis providing detailed assessments of valve haemodynamics and the cardiac remodelling response. Computed tomography (CT) is already widely used in the planning of transcutaneous aortic valve implantation. We anticipate its increased use as an anatomical adjudicator to clarify disease severity in patients with discordant echocardiographic measurements. CT calcium scoring is currently used for this purpose; however, contrast CT techniques are emerging that allow identification of both calcific and fibrotic valve thickening. Additionally, improved assessments of myocardial decompensation with echocardiography, cardiac magnetic resonance, and CT will become more commonplace in our routine assessment of aortic stenosis. Underpinning all of this will be widespread application of artificial intelligence. In combination, we believe this new era of multi-modality imaging in aortic stenosis will improve the diagnosis, follow-up, and timing of intervention in aortic stenosis as well as potentially accelerate the development of the novel pharmacological treatments required for this disease.

Low levels of circulating methylated IRX3 are related to worse outcome after transcatheter aortic valve implantation in patients with severe aortic stenosis

BACKGROUND

Aortic stenosis (AS) is one of the most common cardiac diseases and major cause of morbidity and mortality in the elderly. Transcatheter aortic valve implantation (TAVI) is performed in such patients with symptomatic severe AS and reduces mortality for the majority of these patients. However, a significant percentage dies within the first two years after TAVI, such that there is an interest to identify parameters, which predict outcome and could guide pre-TAVI patient selection. High levels of cardiac fibrosis have been identified as such independent predictor of cardiovascular mortality after TAVI. Promoter hypermethylation commonly leads to gene downregulation, and the Iroquois homeobox 3 (IRX3) gene was identified in a genome-wide transcriptome and methylome to be hypermethylated and downregulated in AS patients. In a well-described cohort of 100 TAVI patients in which cardiac fibrosis levels were quantified histologically in cardiac biopsies, and which had a follow-up of up to two years, we investigated if circulating methylated DNA of IRX3 in the peripheral blood is associated with cardiac fibrosis and/or mortality in AS patients undergoing TAVI and thus could serve as a biomarker to add information on outcome after TAVI.

RESULTS

Patients with high levels of methylation in circulating IRX3 show a significantly increased survival as compared to patients with low levels of IRX3 methylation indicating that high peripheral IRX3 methylation is associated with an improved outcome. In the multivariable setting, peripheral IRX3 methylation acts as an independent predictor of all-cause mortality. While there is no significant correlation of levels of IRX3 methylation with cardiac death, there is a significant but very weak inverse correlation between circulating IRX3 promoter methylation level and the amount of cardiac fibrosis. Higher levels of peripheral IRX3 methylation further correlated with decreased cardiac IRX3 expression and vice versa.

CONCLUSIONS

High levels of IRX3 methylation in the blood of AS patients at the time of TAVI are associated with better overall survival after TAVI and at least partially reflect myocardial IRX3 expression. Circulating methylated IRX3 might aid as a potential biomarker to help guide both pre-TAVI patient selection and post-TAVI monitoring.

The Role of ECG Strain Pattern in Prognosis after TAVI: A Sub-Analysis of the DIRECT Trial

BACKGROUND

The presence of an electrocardiographic (ECG) strain pattern-among other ECG features-has been shown to be predictive of adverse cardiovascular outcomes in asymptomatic patients with aortic stenosis. However, data evaluating its impact on symptomatic patients undergoing TAVI are scarce. Therefore, we tried to investigate the prognostic impact of baseline ECG strain pattern on clinical outcomes after TAVI.

METHODS

A sub-group of patients of the randomized DIRECT (Pre-dilatation in Transcatheter Aortic Valve Implantation Trial) trial with severe aortic stenosis who underwent TAVI with a self-expanding valve in one single center were consecutively enrolled. Patients were categorized into two groups according to the presence of ECG strain. Left ventricular strain was defined as the presence of ≥1 mm convex ST-segment depression with asymmetrical T-wave inversion in leads V5 to V6 on the baseline 12-lead ECG. Patients were excluded if they had paced rhythm or left bundle branch block at baseline. Multivariate Cox proportional hazard regression models were generated to assess the impact on outcomes. The primary clinical endpoint was all-cause mortality at 1 year after TAVI.

RESULTS

Of the 119 patients screened, 5 patients were excluded due to left bundle branch block. Among the 114 included patients (mean age: 80.8 ± 7), 37 patients (32.5%) had strain pattern on pre-TAVI ECG, while 77 patients (67.5%) did not exhibit an ECG strain pattern. No differences in baseline characteristics were found between the two groups. At 1 year, seven patients reached the primary clinical endpoint, with patients in the strain group demonstrating significantly higher mortality in Kaplan-Meier plots compared to patients without left ventricular strain (five vs. two, log-rank p = 0.022). There was no difference between the strain and no strain group regarding the performance of pre-dilatation (21 vs. 33, chi-square p = 0.164). In the multivariate analysis, left ventricular strain was found to be an independent predictor of all-cause mortality after TAVI [Exp(B): 12.2, 95% Confidence Intervals (CI): 1.4-101.9].

CONCLUSION

Left ventricular ECG strain is an independent predictor of all-cause mortality after TAVI. Thus, baseline ECG characteristics may aid in risk-stratifying patients scheduled for TAVI.

Advanced Cardiac Imaging in the Assessment of Aortic Stenosis

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

Incidence and Risk Factors for Long-Term Persistence of Diastolic Dysfunction after Aortic Valve Replacement for Aortic Stenosis Compared with Aortic Regurgitation

(1) Background: Severe left ventricular (LV) diastolic dysfunction with a restrictive diastolic pattern (LVDFP) is generally associated with a worse prognosis. Its evolution and reversibility in the short- and medium-term after aortic valve replacement (AVR) has been little-studied. We aimed to evaluate the evolution of LV remodeling and LV systolic and diastolic function after AVR in aortic stenosis (AS) patients compared to aortic regurgitation (AR). Moreover, we tried to identify the main predictive parameters for postoperative evolution (cardiovascular hospitalization or death and quality of life) and the independent predictors for the persistence of restrictive LVDFP after AVR. (2) Methods: A five-year prospective study on 397 patients undergoing AVR for AS (226 pts) or AR (171 pts), evaluated clinically and by echocardiography preoperatively and until 5 years postoperatively. (3) Results: 1. In patients with AS, early post AVR, LV dimensions decreased and diastolic filling and LV ejection fraction (LVEF) improved more rapidly compared to patients with AR. At 1 year postoperatively, persistent restrictive LVDFP was found especially in the AR group compared to the AS group (36.84% vs. 14.16%). 2. Cardiovascular event-free survival at the 5-year follow-up was lower in the AR group (64.91% vs. 87.17% in the AS group). The main independent predictors of short- and medium-term prognosis after AVR were: restrictive LVDFP, severe LV systolic dysfunction, severe pulmonary hypertension (PHT), advanced age, severe AR, and comorbidities. 3. The persistence of restrictive LVDFP after AVR was independently predicted by: preoperative AR, the E/Ea ratio > 12, the LA dimension index > 30 mm/m², an LV endsystolic diameter (LVESD) > 55 mm, severe PHT, and associated second-degree MR (p < 0.05). (4) Conclusions: AS patients had an immediate postoperative evolution in terms of LV remodeling, and LV systolic and diastolic function were more favorable compared to those with AR. The restrictive LVDFP was reversible, especially after the AVR for AS. The main prognostic predictors were the presence of restrictive LVDFP, advanced age, preoperative AR, severe LV systolic dysfunction, and severe PHT.

Heart Failure with Preserved Ejection Fraction in Children

Diastolic dysfunction (DD) refers to abnormalities in the mechanical function of the left ventricle (LV) during diastole. Severe LVDD can cause symptoms and the signs of heart failure (HF) in the setting of normal or near normal LV systolic function and is referred to as diastolic HF or HF with preserved ejection fraction (HFpEF). Pediatric cardiologists have long speculated HFpEF in children with congenital heart disease and cardiomyopathy. However, understanding the risk factors, clinical course, and validated biomarkers predictive of the outcome of HFpEF in children is challenging due to heterogeneous etiologies and overlapping pathophysiological mechanisms. The natural history of HFpEF varies depending upon the patient's age, sex, race, geographic location, nutritional status, biochemical risk factors, underlying heart disease, and genetic-environmental interaction, among other factors. Pediatric onset HFpEF is often not the same disease as in adults. Advances in the noninvasive evaluation of the LV diastolic function by strain, and strain rate analysis with speckle-tracking echocardiography, tissue Doppler imaging, and cardiac magnetic resonance imaging have increased our understanding of the HFpEF in children. This review addresses HFpEF in children and identifies knowledge gaps in the underlying etiologies, pathogenesis, diagnosis, and management, especially compared to adults with HFpEF.

Valvular heart disease: shifting the focus to the myocardium

Adverse cardiac remodelling is the main determinant of patient prognosis in degenerative valvular heart disease (VHD). However, to give an indication for valvular intervention, current guidelines include parameters of cardiac chamber dilatation or function which are subject to variability, do not directly reflect myocardial structural changes, and, more importantly, seem to be not sensitive enough in depicting early signs of myocardial dysfunction before irreversible myocardial damage has occurred. To avoid irreversible myocardial dysfunction, novel biomarkers are advocated to help refining indications for intervention and risk stratification. Advanced echocardiographic modalities, including strain analysis, and magnetic resonance imaging have shown to be promising in providing new tools to depict the important switch from adaptive to maladaptive myocardial changes in response to severe VHD. This review, therefore, summarizes the current available evidence on the role of these new imaging biomarkers in degenerative VHD, aiming at shifting the clinical perspective from a valve-centred to a myocardium-focused approach for patient management and therapeutic decision-making.

The association of left ventricular histologically verified myocardial fibrosis with pulmonary hypertension in severe aortic stenosis

OBJECTIVES

To evaluate the association between histologically verified left ventricular (LV) myocardial fibrosis (MF) and its bio- and functional markers with pulmonary hypertension (PH) in severe aortic stenosis (AS).

METHODS

About 34 patients with isolated severe AS underwent 2D echocardiography, cardiac magnetic resonance (CMR) imaging, and plasma NT-proBNP evaluation before aortic valve replacement (AVR). LV measurements were analyzed by CMR and LV strain using feature tracking software (Medis Suite QStrain 2.0). Myocardial biopsy sampled at the time of AVR was assessed by a histomorphometric analysis. PH was defined as pulmonary artery systolic pressure (PASP) ⩾ 45 mm Hg.

RESULTS

Patients with severe AS and PH (mean PASP 53 ± 3.7 mm Hg) had higher extent of diffuse MF versus patients without PH (12 (10.4-12.7)% vs 6.6 (4.6-8.2)% (p = 0.00)). The extent of diffuse MF correlated with LV dilatation (r = 0.7, p = 0.02), indices of LV dysfunction (lower ejection fraction (r = -0.6, p < 0.001), global longitudinal (r = -0.5, p = 0.02) and circumferential strain (r = -0.5, p = 0.05), elevated NT-proBNP (r = 0.5, p = 0.005) and elevated PASP (r = 0.6, p < 0.001)). Histological MF > 10% (AUC 94.9%), LV global longitudinal strain > -15.5% (AUC 86.3%), and NT-proBNP > 2090 ng/l (AUC 85.1%) were independent predictors of PH in severe AS.

CONCLUSIONS

The extent of diffuse myocardial fibrosis in combination with reduced longitudinal left ventricular strain and increased plasma levels of NT-proBNP relates to pulmonary hypertension in severe aortic stenosis.

Multimodality Imaging to Explore Sex Differences in Aortic Stenosis

The aim of this article is to review sex differences in aortic stenosis (AS) assessed with multimodality imaging. Echocardiography remains the mainstay imaging technique to diagnose AS and provides important insights into the differences between men and women in relation to valve haemodynamic and left-ventricular response. However, echocardiography does not have adequate resolution to provide important insights into sex differences in the degenerative, calcific pathophysiological process of the aortic valve. CT shows that women with AS have more fibrotic changes of the aortic valve whereas men show more calcific deposits. Cardiac magnetic resonance shows that women have left ventricles that are less hypertrophic and smaller compared with those of men, while men have more replacement myocardial fibrosis. These differences may lead to different responses to aortic valve replacement because myocardial diffuse fibrosis but not replacement myocardial fibrosis may regress after the procedure. Sex differences in the pathophysiological process of AS can be assessed using multimodality imaging, assisting in decisionmaking in these patients.

Sex-dependent expression of neutrophil gelatinase-associated lipocalin in aortic stenosis

BACKGROUND

Accumulating evidence suggest the existence of sex-related differences in the pathogenesis of aortic stenosis (AS) with inflammation, oxidative stress, fibrosis and calcification being over-represented in men. Neutrophil gelatinase-associated lipocalin (NGAL) is expressed in a myriad of tissues and cell types, and it is associated with acute and chronic pathological processes comprising inflammation, fibrosis or calcification. Sex-dependent signatures have been evidenced for NGAL which expression has been associated predominantly in males to metabolic and cardiovascular disorders. We aimed to analyse sex-related differences of NGAL in AS and its role in the inflammatory and fibrocalcific progression of AS.

METHODS AND RESULTS

220 (60.45% men) patients with severe AS elective for surgical aortic valve (AV) replacement were recruited. Immunohistochemistry revealed higher expression of NGAL in calcific areas of AVs and that was validated by qPCR in in 65 (60% men) donors. Valve interstitial cells (VICs) were a source of NGAL in these samples. Proteome profiler analyses evidenced higher expression of NGAL in men compared to women, and that was further validated by ELISA. NGAL expression in the AV was correlated with inflammation, oxidative stress, and osteogenic markers, as well as calcium score. The expression of NGAL, both intracellular and secreted (sNGAL), was significantly deregulated only in calcifying male-derived VICs. Depletion of intracellular NGAL in calcifying male-derived VICs was associated with pro-inflammatory profiles, dysbalanced matrix remodelling and pro-osteogenic profiles. Conversely, exogenous NGAL mediated inflammatory and dysbalanced matrix remodelling in calcifying VICs, and all that was prevented by the pharmacological blockade of NGAL.

CONCLUSIONS

Owing to the over-expression of NGAL, the AV from men may be endowed with higher expression of inflammatory, oxidative stress, matrix remodelling and osteogenic markers supporting the progression of calcific AS phenotypes. The expression of NGAL in the VIC emerges as a potential therapeutic checkpoint, with its effects being potentially reverted by the pharmacological blockade of extracellular NGAL.

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.

Additional Prognostic Value of Tissue Doppler Evaluation in Patients with Aortic Stenosis and Left-Ventricular Systolic Dysfunction Undergoing Aortic Valve Replacement

Background and Objectives: Patients with surgical aortic stenosis (AS) show impaired diastolic filling, which is a risk factor for early and late mortality after aortic valve replacement (AVR). There is a paucity of information concerning the impact of restrictive diastolic filling and the evolution of diastolic dysfunction in the early and medium terms post-AVR. We aimed to determine the prognostic value of the presence of a restrictive left-ventricular (LV) diastolic filling pattern (LVDFP) and dilated left atrium (LA) in patients with AS and LV systolic dysfunction (LVEF < 40%) who underwent AVR, and to define the independent predictors for immediate and long-term prognosis and their value for preoperative risk estimation. Materials and Methods: The study was prospective and included 197 patients with surgical AS and LVEF <40% who underwent AVR. Preoperative echocardiographic examinations were repeated at day 10, at 1, 3 and 6 months, and at 1 and 2 years after surgery, with evaluation of LVEF, diastolic function and LA dimension index (mm/m2). Depending on LV systolic performance, patients were classified as Group A (LVEF: 30−40%) or Group B (LVEF < 30%). Results: The main echographic independent parameters for early and late postoperative death were: restrictive LVDFP, significant pulmonary hypertension, LV end-systolic diameter (LVESD) >55 mm and the presence of second-degree mitral regurgitation. Restrictive LVDFP and LA dimension >30 mm/m2 were independent predictors for fatal outcome (p = 0.0017). Conclusions: Assessment of diastolic function and LA dimension are reliable parameters in predicting fatal outcome and hospitalization for heart failure, having an independent and incremental prognostic value in patients with surgical AS. Complete evaluation of LVDFP with all the echographic measurements (including TDI) should routinely be part of the preoperative assessment of patients with LV systolic dysfunction undergoing AVR.

Myocardial fibrosis in asymptomatic patients undergoing surgery for mitral and aortic valve regurgitation

BACKGROUND

Chronic heart valve regurgitation induces left ventricular (LV) volume overload, leading to the development of hypertrophy and progressive dilatation of the ventricle to maintain physiological cardiac output. In order to prevent potential irreversible LV structural changes, the identification of the best timing for treatment is pivotal.

OBJECTIVE

To assess the presence and extent of fibrosis in myocardial tissue in asymptomatic patients with valvular heart disease (VHD) and preserved LV dimensions and function undergoing cardiac surgery.

METHODS

Thirty-nine patients were enrolled. Sixteen patients were affected by aortic or mitral regurgitation: they were all asymptomatic, undergoing valve surgery according to VHD European Society of Cardiology guidelines. Twenty-three patients with end-stage nonischemic dilated cardiomyopathy (DCM) and severe LV dysfunction undergoing cardiac surgery for implantation of a durable left ventricular assist device (LVAD) served as controls. During surgery, VHD patients underwent three myocardial biopsies at the level of the septum, the lateral wall and LV apex, while in LVAD patients the coring of the apex of the LV was used. For both groups, the tissue samples were analyzed on one section corresponding to the apical area. All slides were stained with hematoxylin and eosin and Masson's trichrome staining and further digitalized. The degree of fibrosis was then calculated as a percentage of the total area.

RESULTS

Of 39 patients, 23 met the inclusion criteria: 12 had mitral or aortic insufficiency with a preserved ejection fraction and 11 had idiopathic dilated cardiomyopathy. Quantitative analysis of apical sections revealed a myocardial fibrosis amount of 10 ± 6% in VHD patients, while in LVAD patients the mean apical myocardial fibrosis rate was 38 ± 9%. In VHD patients, fibrosis was also present in the lateral wall (9 ± 4%) and in the septum (9 ± 6%).

CONCLUSION

Our case series study highlights the presence of tissue remodeling with fibrosis in asymptomatic patients with VHD and preserved LV function. According to our results, myocardial fibrosis is present at an early stage of the disease, well before developing detectable LV dysfunction and symptoms. Since the relationship between the progressive magnitude of myocardial fibrosis and potential prognostic implications are not yet defined, further studies on this topic are warranted.

Network modeling predicts personalized gene expression and drug responses in valve myofibroblasts cultured with patient sera

Aortic valve stenosis (AVS) patients experience pathogenic valve leaflet stiffening due to excessive extracellular matrix (ECM) remodeling. Numerous microenvironmental cues influence pathogenic expression of ECM remodeling genes in tissue-resident valvular myofibroblasts, and the regulation of complex myofibroblast signaling networks depends on patient-specific extracellular factors. Here, we combined a manually curated myofibroblast signaling network with a data-driven transcription factor network to predict patient-specific myofibroblast gene expression signatures and drug responses. Using transcriptomic data from myofibroblasts cultured with AVS patient sera, we produced a large-scale, logic-gated differential equation model in which 11 biochemical and biomechanical signals were transduced via a network of 334 signaling and transcription reactions to accurately predict the expression of 27 fibrosis-related genes. Correlations were found between personalized model-predicted gene expression and AVS patient echocardiography data, suggesting links between fibrosis-related signaling and patient-specific AVS severity. Further, global network perturbation analyses revealed signaling molecules with the most influence over network-wide activity, including endothelin 1 (ET1), interleukin 6 (IL6), and transforming growth factor β (TGFβ), along with downstream mediators c-Jun N-terminal kinase (JNK), signal transducer and activator of transcription (STAT), and reactive oxygen species (ROS). Lastly, we performed virtual drug screening to identify patient-specific drug responses, which were experimentally validated via fibrotic gene expression measurements in valvular interstitial cells cultured with AVS patient sera and treated with or without bosentan-a clinically approved ET1 receptor inhibitor. In sum, our work advances the ability of computational approaches to provide a mechanistic basis for clinical decisions including patient stratification and personalized drug screening.

Prognostic value of cardiac magnetic resonance in patients with aortic stenosis: A systematic review and meta-analysis

BACKGROUND

The timing of surgery for aortic stenosis (AS) is imperfect, and the management of moderate AS and asymptomatic severe AS is still challenging. Myocardial fibrosis (MF) is the main pathological basis of cardiac decompensation in patients with AS and can be detected by cardiovascular magnetic resonance (CMR). The aim of this study was to evaluate the prognostic value of MF measured by CMR in patients with AS, which can provide a reference for the timing of aortic valve replacement (AVR).

METHODS

We searched Medline, Embase, and Web of Science to include all studies that investigated the prognostic value of CMR in patients with AS. The search deadline is March 31, 2021. The pooled relative risk (RR) or hazard ratio (HR) and 95% confidence intervals (CI) of the biomarkers including late gadolinium enhancement (LGE), Native T1 or extracellular volume (ECV) were calculated to evaluate the prognostic value.

RESULTS

13 studies and 2,430 patients with AS were included in this study, the mean or medium follow-up duration for each study was ranged from 6 to 67.2 months. Meta-analysis showed the presence of LGE was associated with an increased risk for all-cause mortality (pooled RR: 2.14, 95% CI: 1.67-2.74, P < 0.001), cardiac mortality (pooled RR: 3.50, 95% CI: 2.32-5.30, P < 0.001), and major adverse cardiovascular events (MACEs) (pooled RR: 1.649, 95% CI: 1.23-2.22, P = 0.001). Native T1 was significantly associated with MACEs (pooled RR: 2.23, 95% CI: 1.00-4.95; P = 0.049), and higher ECV was associated with a higher risk of cardiovascular events (pooled HR: 1.69, 95% CI: 1.11-2.58; P = 0.014).

CONCLUSION

The use of CMR to detect MF has a good prognostic value in patients with AS. LGE, Native T1 and ECV measured by CMR can contribute to risk stratification of AS, thereby helping to optimize the timing of AVR.

Fragmented QRS complex may predict long-term mortality after isolated surgical aortic valve replacement in patients with severe aortic stenosis

OBJECTIVES

Fragmented QRS (fQRS), related to myocardial fibrosis, is an important prognostic marker of cardiovascular events and mortality. Aortic stenosis (AS), the most frequent valvular heart disease in developed countries, causes myocardial fibrosis due to ventricular pressure overload. The current study aimed to investigate whether fQRS is associated with long-term mortality after isolated surgical aortic valve replacement (SAVR) in patients with severe AS.

METHODS

A total of 289 patients who underwent SAVR for severe AS between May 2009 and January 2020 with interpretable electrocardiogram were included. Patients were divided into 2 groups according to the presence of fQRS. Kaplan-Meier survival analyses were used to detect cumulative survival rates. Univariable and multivariable Cox proportional hazards models were used to determine the predictors of all-cause mortality.

RESULTS

fQRS occurred in 126 (43.5%) patients. A total of 59 (20.4%) patients died over a follow-up period of 54 ± 32 months. All-cause mortality was higher in the fQRS group (23 [14.1%] vs 36 [28.6], log-rank test P = 0.002) in the long term. The presence of fQRS [hazard ratio (HR): 1.802, confidence interval (CI): 1.035-3.135, P = 0.037], electrocardiographic left ventricular strain (HR: 1.836, CI: 1.036-3.254, P = 0.038) and history of stroke or transient ischaemic attack (HR: 3.130, CI: 1.528-6.412, P = 0.002) were independent predictors of all-cause mortality in the multivariable Cox regression model.

CONCLUSIONS

fQRS is associated with a 1.8-fold increase in long-term mortality in patients undergoing isolated SAVR for severe AS. Detecting fQRS in electrocardiograms may provide prognostic information about the long-term outcomes.

Proteomic mapping of atrial and ventricular heart tissue in patients with aortic valve stenosis

Aortic valve stenosis (AVS) is one of the most common valve diseases in the world. However, detailed biological understanding of the myocardial changes in AVS hearts on the proteome level is still lacking. Proteomic studies using high-resolution mass spectrometry of formalin-fixed and paraffin-embedded (FFPE) human myocardial tissue of AVS-patients are very rare due to methodical issues. To overcome these issues this study used high resolution mass spectrometry in combination with a stem cell-derived cardiac specific protein quantification-standard to profile the proteomes of 17 atrial and 29 left ventricular myocardial FFPE human myocardial tissue samples from AVS-patients. In our proteomic analysis we quantified a median of 1980 (range 1495–2281) proteins in every single sample and identified significant upregulation of 239 proteins in atrial and 54 proteins in ventricular myocardium. We compared the proteins with published data. Well studied proteins reflect disease-related changes in AVS, such as cardiac hypertrophy, development of fibrosis, impairment of mitochondria and downregulated blood supply. In summary, we provide both a workflow for quantitative proteomics of human FFPE heart tissue and a comprehensive proteomic resource for AVS induced changes in the human myocardium.

Prognostic Impact of Myocardial Extracellular Volume Fraction Assessment Using Dual-Energy Computed Tomography in Patients Treated With Aortic Valve Replacement for Severe Aortic Stenosis

Background Myocardial extracellular volume fraction (ECV), measured by cardiac magnetic resonance imaging, is a useful prognostic marker for patients who have undergone aortic valve replacement (AVR) for aortic stenosis. However, the prognostic significance of ECV measurements based on computed tomography (CT) is unclear. This study evaluated the association between ECV measured with dual-energy CT and clinical outcomes in patients with aortic stenosis who underwent transcatheter or surgical AVR. Methods and Results We retrospectively enrolled 95 consecutive patients (age, 84.0±5.0 years; 75% women) with severe aortic stenosis who underwent preprocedural CT for transcatheter AVR planning. ECV was measured using iodine density images obtained by delayed enhancement dual-energy CT. The primary end point was a composite outcome of all-cause death and hospitalization for heart failure after AVR. The mean ECV measured with CT was 28.1±3.8%. During a median follow-up of 2.6 years, 22 composite outcomes were observed, including 15 all-cause deaths and 11 hospitalizations for heart failure. In Kaplan-Meier analysis, the high ECV group (≥27.8% [median value]) had significantly higher rates of composite outcomes than the low ECV group (<27.8%) (log-rank test, P=0.012). ECV was the only independent predictor of adverse outcomes on multivariable Cox regression analysis (hazards ratio, 1.25; 95% CI, 1.10‒1.41; P<0.001). Conclusions Myocardial ECV measured with dual-energy CT in patients who underwent aortic valve intervention was an independent predictor of adverse outcomes after AVR.

Prognostic significance of vascular and valvular calcifications in low- and high-gradient aortic stenosis

AIMS

In low-gradient aortic stenosis (LGAS), the high valvulo-arterial impedance observed despite low valvular gradient suggests a high vascular load. Thoracic aortic calcifications (TACs) and valvular aortic calcifications (VACs) are, respectively, surrogates of aortic load and aortic valvular gradient. The aim of this study was to compare the respective contributions of TAC and VAC on 3-year cardiovascular (CV) mortality following TAVI in LGAS vs. high-gradient aortic stenosis (HGAS) patients.

METHODS AND RESULTS

A total of 1396 consecutive patients were included. TAC and VAC were measured on the pre-TAVI CT-scan. About 435 (31.2%) patients had LGAS and 961 (68.8%) HGAS. LGAS patients were more prone to have diabetes, coronary artery disease (CAD), atrial fibrillation (AF), and lower left ventricular ejection fraction (LVEF), P<0.05 for all. During the 3 years after TAVI, 245(17.8%) patients experienced CV mortality, 92(21.6%) in LGAS and 153(16.2%) in HGAS patients, P=0.018. Multivariate analysis adjusted for age, gender, diabetes, AF, CAD, LVEF, renal function, vascular access, and aortic regurgitation showed that TAC but not VAC was associated with CV mortality in LGAS, hazard ratio (HR) 1.085 confidence interval (CI) (1.019-1.156), P=0.011, and HR 0.713 CI (0.439-1.8), P=0.235; the opposite was observed in HGAS patients with VAC but not TAC being associated with CV mortality, HR 1.342 CI (1.034-1.742), P=0.027, and HR 1.015 CI (0.955-1.079), P=0.626.

CONCLUSION 

TAC plays a major prognostic role in LGAS while VAC remains the key in HGAS patients. This confirms that LGAS is a complex vascular and valvular disease.

[Role of magnetic resonance imaging in patients with aortic stenosis before and after replacement of the valve]

Risk stratification among patients with aortic stenosis remains inadequate, and there is a clinical need for the correct identification of high-risk patients who would benefit from aortic valve intervention before developing left ventricular decompensation. Since the publication of the results of the PARTNER study, transcatheter aortic valve implantation (TAVI) has become the method of choice for aortic valve stenosis in inoperable patients and is a real alternative to conventional surgical replacement of the aortic valve in high-risk patients. In planning TAVI and postoperative monitoring of a patient from imaging methods, the leading role is played by echocardiography and multispiral computed tomography. However, in recent years, the interest of researchers in the use of magnetic resonance imaging in this category of patients has increased. The review article examines the potential role of magnetic resonance imaging in patients with aortic stenosis before and after TAVI.

Synthetic Prostacyclin Agonist Attenuates Pressure-Overloaded Cardiac Fibrosis by Inhibiting FMT

Fibroblast-to-myofibroblast transition (FMT) is the primary inducer of cardiac fibrosis. ONO-1301, a synthetic prostacyclin agonist, reportedly promotes tissue fibrosis repair by enhancing anti-fibrotic cytokine production. We hypothesized that ONO-1301 attenuates pressure-overloaded cardiac fibrosis by modulating FMT and generated a pressure-overloaded murine model via transverse aortic constriction (TAC) to evaluate the in vivo effects of ONO-1301. Cardiac fibrosis, left ventricular dilatation, and systolic dysfunction were established 4 weeks after TAC; however, ONO-1301 treatment initiated 2 weeks after TAC significantly attenuated those effects. Furthermore, ONO-1301 treatment significantly upregulated expression levels of cardioprotective cytokines such as vascular endothelial growth factor and hepatocyte growth factor in TAC hearts, whereas FMT-related factors, including transforming growth factor (TGF)-β1 and connective tissue growth factor, were significantly downregulated. The number of α-smooth muscle actin (α-SMA)- and vimentin-positive cells, representing fibroblast-originated cells transitioned into myofibroblasts, was significantly reduced in ONO-1301-treated TAC hearts. We isolated cardiac fibroblasts (CFs) from the left ventricles of adult male mice and assessed the effects of ONO-1301 on CFs stimulated by TGF-β. Results showed that ONO-1301 co-incubation significantly suppressed TGF-β-induced α-SMA expression and collagen synthesis, and significantly inhibited TGF-β-induced CF proliferation and migration. Our findings suggest that ONO-1301 ameliorates pressure overloaded cardiac fibrosis by inhibiting TGF-β-induced FMT.

Infective Endocarditis After Transcatheter Versus Surgical Aortic Valve Replacement: A Meta-Analysis

We determined the incidence, clinical characteristics, and risk factors of post-transcatheter aortic valve replacement (TAVR)-associated infective endocarditis (IE). We compared the incidence of IE after TAVR versus after surgical aortic valve replacement (SAVR). The incidence rate of IE 1-year post-TAVR was 0.9% (95% confidence interval [CI]: 0.8-1.0). Transcatheter aortic valve replacement was associated with significantly reduced IE incidence (incidence rate ratio: 0.69, 95% CI: 0.52-0.92, P = .011) compared with SAVR. In patients with TAVR IE, the pooled in-hospital mortality was 37.8% (95% CI: 32.4-43.3, I ² = 54.9%). Pooled adjusted hazard ratio (HR) revealed that peri-procedural peripheral artery disease (HR: 4.02, 95% CI: 2.28-7.10, P < .0001), moderate or severe residual aortic regurgitation (HR: 2.34, 95% CI: 1.53-3.59, P < .0001), orotracheal intubation (HR: 2.13, 95% CI: 1.19-3.82, P = .011), and male gender (HR: 1.70, 95% CI: 1.47-1.97, P < .0001) were risk factors for post-TAVR IE. Post-TAVR IE is a life-threatening complication often resulting in in-hospital mortality. The current evidence-based meta-analysis to identify risk factors may lead to the development of effective preventive and therapeutic strategies for post-TAVR IE to ultimately improve patient outcomes.

Late Gadolinium Enhancement Predicts Improvement in Global Longitudinal Strain after Aortic Valve Replacement in Aortic Stenosis

Myocardial fibrosis, as detected by late gadolinium enhancement (LGE) magnetic resonance imaging (MRI), is related to mortality after aortic valve replacement (AVR). This study aimed to determine whether LGEMRI predicts improvement in global longitudinal strain (GLS) after AVR in patients with severe aortic stenosis (AS). Twenty-nine patients with severe AS who were scheduled to undergo AVR were enrolled. Two-dimensional echocardiography and contrast-enhanced MRI were performed before AVR. GLS and LGEcore (g: > 5 SD of normal area), LGEgray (g: 2–5 SD), and LGEcore+gray (g) were measured. One year after AVR, GLS were examined by echocardiography to assess improvement in LV function. Preoperatively, GLS correlated with LGEcore (g) (r² = 0.14, p < 0.05), LGEgray (g) (r² = 0.32, p < 0.01) and LGEcore+gray (g) (r² = 0.36, p < 0.01). LGEcore was significantly lower in patients with improved GLS after AVR (GLS_1year ≥ −19.9%) compared to those with no improvement (1.34 g vs. 4.70 g, p < 0.01). LGE predicts improvement in LV systolic function after AVR.

Advanced cardiac MRI techniques for evaluation of left-sided valvular heart disease

The most common types of left‐sided valvular heart disease (VHD) in the Western world are aortic valve stenosis, aortic valve regurgitation, and mitral valve regurgitation. Comprehensive clinical evaluation entails both hemodynamic analysis and structural as well as functional characterization of the left ventricle. Cardiac magnetic resonance imaging (MRI) is an established diagnostic modality for assessment of left‐sided VHD and is progressively gaining ground in modern‐day clinical practice. Detailed flow visualization and quantification of flow‐related biomarkers in VHD can be obtained using 4D flow MRI, an imaging technique capable of measuring blood flow in three orthogonal directions over time. In addition, recent MRI sequences enable myocardial tissue characterization and strain analysis. In this review we discuss the emerging potential of state‐of‐the‐art MRI including 4D flow MRI, tissue mapping, and strain quantification for the diagnosis and prognosis of left‐sided VHD.

Level of Evidence: 1

Technical Efficacy Stage: 1

J. Magn. Reson. Imaging 2018. J. MAGN. RESON. IMAGING 2018;48:318–329.

Fibroblasts and Their Pathological Functions in the Fibrosis of Aortic Valve Sclerosis and Atherosclerosis

Cardiovascular diseases, such as atherosclerosis and aortic valve sclerosis (AVS) are driven by inflammation induced by a variety of stimuli, including low-density lipoproteins (LDL), reactive oxygen species (ROS), infections, mechanical stress, and chemical insults. Fibrosis is the process of compensating for tissue injury caused by chronic inflammation. Fibrosis is initially beneficial and maintains extracellular homeostasis. However, in the case of AVS and atherosclerosis, persistently active resident fibroblasts, myofibroblasts, and smooth muscle cells (SMCs) perpetually remodel the extracellular matrix under the control of autocrine and paracrine signaling from the immune cells. Myofibroblasts also produce pro-fibrotic factors, such as transforming growth factor-β1 (TGF-β1), angiotensin II (Ang II), and interleukin-1 (IL-1), which allow them to assist in the activation and migration of resident immune cells. Post wound repair, these cells undergo apoptosis or become senescent; however, in the presence of unresolved inflammation and persistence signaling for myofibroblast activation, the tissue homeostasis is disturbed, leading to excessive extracellular matrix (ECM) secretion, disorganized ECM, and thickening of the affected tissue. Accumulating evidence suggests that diverse mechanisms drive fibrosis in cardiovascular pathologies, and it is crucial to understand the impact and contribution of the various mechanisms for the control of fibrosis before the onset of a severe pathological consequence.

Expert consensus document on the assessment of the severity of aortic valve stenosis by echocardiography to provide diagnostic conclusiveness by standardized verifiable documentation

According to recent recommendations on echocardiographic assessment of aortic valve stenosis direct measurement of transvalvular peak jet velocity, calculation of transvalvular mean gradient from the velocities using the Bernoulli equation and calculation of the effective aortic valve area by continuity equation are the appropriate primary key instruments for grading severity of aortic valve stenosis. It is obvious that no gold standard can be declared for grading the severity of aortic stenosis. Thus, conclusions of the exclusive evaluation of aortic stenosis by Doppler echocardiography seem to be questionable due to the susceptibility to errors caused by methodological limitations, mathematical simplifications and inappropriate documentation. The present paper will address practical issues of echocardiographic documentation to satisfy the needs to analyze different scenarios of aortic stenosis due to various flow conditions and pressure gradients. Transesophageal and multidimensional echocardiography should be implemented for reliable measurement of geometric aortic valve area and of cardiac dimensions at an early stage of the diagnostic procedure to avoid misinterpretation due to inconsistent results.

Impact of High Baseline Left Ventricular Filling Pressure on Transcatheter Aortic Valve Replacement Outcomes in Patients with Significant Mitral Annular Calcification

BACKGROUND

Left ventricular filling pressure (LVFP) has been demonstrated to be a major predictor of poor cardiovascular outcomes. However, estimation of LVFP in patients with aortic stenosis is limited by the high prevalence of significant mitral annular calcification. The aim of this study was to investigate the effect of transcatheter aortic valve replacement on LVFP and the relationship of LVFP to mortality and hospitalization.

METHODS

This was a single-center, retrospective study of 140 consecutive patients in sinus rhythm with significant mitral annular calcification who underwent transcatheter aortic valve replacement for severe aortic stenosis from May 2011 to June 2015. Mean follow-up duration was 3.06 ± 1.48 years (minimum, 2.4 years; maximum, 6.5 years). Diastolic function was assessed using recently proposed criteria for those with significant mitral annular calcification. High LVFP was defined as a mitral E/A ratio > 1.8 or a ratio of 0.8 to 1.8 and isovolumic relaxation time < 80 msec.

RESULTS

At baseline, the proportion of patients with high LVFP was 40.7%, similar to 1 month (39.7%) (P = .86). However, the proportion of patients with high LVFP was significantly decreased at 1 year compared with those at baseline (26.9% vs 40.7%, P = .02). Multivariate analysis showed that high LVFP at baseline significantly increased risk for all-cause mortality compared with patients with normal LVFP (hazard ratio, 2.84; 95% confidence interval, 1.33-6.05; P = .007).

CONCLUSIONS

High baseline LVFP was associated with a significantly increased all-cause mortality, and LVFP does not improve in the short term but only at 1 year after transcatheter aortic valve replacement.

Remodeling classification system considering left ventricular volume in patients with aortic valve stenosis: Association with adverse cardiovascular outcomes

BACKGROUND

To assess prevalence and clinical implications of left ventricular (LV) remodeling considering: LV volume, mass and relative wall thickness at the time of aortic valve stenosis diagnosis.

METHODS AND RESULTS

We retrospectively analyzed 343 patients (age 79.2 ± 9.5 years, 48.1% males) with functional aortic valve area (AVA) ≤ 1.5 cm² . LV geometric patterns and clinical outcomes (combined death, cardiac hospitalization, aortic valve replacement [AVR]) were evaluated. According to the new LV remodeling classification, 4.9% had normal geometry, 7.5% concentric remodeling, 39.3% concentric hypertrophy (LVH), 22.4% mixed LVH, 12.5% dilated LVH, 3.2% eccentric LVH and 4.3% eccentric remodeling, 5.5% had not classifiable LVH. Indexed stroke volume (SVi) was higher in patients with concentric LVH (40.3 ± 11.9 mL/m² ) and mixed LVH (41.6 ± 13.4 mL/m² ) and lower in patients with eccentric LVH (24.9 ± 7.7 mL/m² ), concentric (36.6 ± 12.7 mL/m² ) and eccentric remodeling (34.9 ± 9.5 mL/m² ), P = 0.003. During a median follow-up of 2.2 years, 260 (75.8%) had the combined end point. A significant association between the combined end point and LV dilation (P = 0.010) or LV remodeling patterns (P = 0.0001) was found. After multivariable adjustment for AVR, concentric remodeling (HR 3.12, IC 95% 1.14-8.55; P = 0.02) and dilated LVH (HR 3.48, IC 95% 1.31-9.27; P = 0.01) were strongly associated with death or cardiac hospitalizations.

CONCLUSIONS

In patients with AVA ≤ 1.5 cm² , when the new LV remodeling classification system is applied, only a minority had normal geometry and less than half had "classic" concentric LVH or remodeling. LV volume dilatation is frequent and associated with adverse outcome. Concentric remodeling, eccentric remodeling, dilated LVH had the worst noninvasive hemodynamic profile and prognosis.

Incremental Predictive Value of Longitudinal Axis Strain and Late Gadolinium Enhancement Using Standard CMR Imaging in Patients with Aortic Stenosis

To analyse the predictive ability and incremental value of left ventricular longitudinal axis strain (LAS) and late gadolinium enhancement (LGE) using standard cardiovascular magnetic resonance (CMR) imaging for the diagnosis and prognosis of severe aortic stenosis (AS) in patients with an indication for aortic valve replacement. We conducted a prospective study on 52 patients with severe AS and 52 volunteers. The evaluation protocol included standard biochemistry tests, novel biomarkers of myocardial fibrosis, 12-lead electrocardiograms and 24-hour Holter, the 6-minute walk test and extensive echocardiographic and CMR imaging studies. Outcomes were defined as the composite of major cardiovascular events (MACEs). Among AS patients, most (n = 17, 77.2%) of those who exhibited LGE at CMR imaging had MACEs during follow-up. Kaplan–Meier curves for event-free survival showed a significantly higher rate of MACEs in patients with LGE (p < 0.01) and decreased LAS (p < 0.001). In Cox regression analysis, only reduced LAS (hazard ratio 1.33, 95% CI (1.01 to 1.74), p < 0.01) and the presence of LGE (hazard ratio 11.3, 95% CI (1.82 to 70.0), p < 0.01) were independent predictors for MACEs. The predictive value increased if both LGE and reduced LAS were added to left ventricular ejection fraction (LVEF). None of the biomarkers of increased collagen turnover exhibited any predictive value for MACEs. LAS by CMR is an independent predictor of outcomes in patients with AS and provides incremental value beyond the assessment of LVEF and the presence of LGE.

Imaging of Myocardial Fibrosis and Its Functional Correlates in Aortic Stenosis: A Review and Clinical Potential

Patients with severe aortic stenosis (AS) show progressive fibrotic changes in the myocardium, which may impair cardiac function and patient outcomes even after successful aortic valve replacement. Detection of patients who need an early operation remains a diagnostic challenge as myocardial functional changes may be subtle. In recent years, speckle tracking echocardiography (STE) and cardiac magnetic resonance mapping have been shown to provide complementary information for the assessment of left ventricular mechanics and identification of subtle damage by focal or diffuse myocardial fibrosis, respectively. Little is known, however, about how focal and diffuse myocardial fibrosis occurring in severe AS are related to measurable functional changes by echocardiography and to which extent both parameters have prognostic and diagnostic value. The aims of this review are to discuss the occurrence of focal and diffuse myocardial fibrosis in patients with severe AS and to explore their relation with myocardial function, determined by STE, as well as the prognostic and diagnostic potential of both parameters.

The prognostic value of fragmented QRS in patients undergoing transcatheter aortic valve implantation

BACKGROUND

Although transcatheter aortic valve implantation (TAVI) can successfully correct aortic narrowing, pre-existing pathophysiological alterations in the left ventricle are still a concern in terms of long-term mortality. This study aimed to examine the predictive role of fQRS morphology on long-term prognosis in patients undergoing TAVI due to severe aortic stenosis.

METHODS

A total of 117 patients undergoing TAVI due to severe aortic stenosis were included in this retrospective cohort study. Patients were assigned into two groups based on the presence (n = 36) or absence (n = 81) of fQRS. Predictors of long-term survival were estimated.

RESULTS

In-hospital mortality was higher in fQRS group (5.5% vs. 1.2%, p = 0.0224). In the long-term, fQRS (OR: 3.06, 95% CI 1.29-7.27, p: 0.01), LVEF <50% (OR: 2.54, 95% CI 1.07-6.02, p: 0.03) and presence of atrial fibrillation (OR: 2.42, 95% CI 1.05-5.60, p: 0.03) emerged as significant independent predictors of short survival.

CONCLUSION

Presence of fQRS on ECG, an indirect indicator of myocardial fibrosis, seems to have the potential to be used as a prognostic marker after TAVI procedure. Large prospective studies are warranted.

Myocardial T1 and T2 mapping in severe aortic stenosis: Potential novel insights into the pathophysiology of myocardial remodelling

PURPOSE

Severe aortic stenosis (AS) is known to be associated with substantial myocardial remodelling, leading to diffuse myocardial fibrosis (DMF). Native myocardial T1 is emerging as a novel imaging biomarker for the non-invasive assessment of DMF. In contrast, no studies exist elucidating changes of myocardial T2 reflecting myocardial oedema in the presence of AS. The purpose of the present study was to combine native T1 and T2 mapping in order to characterize myocardial tissue changes in the setting of severe AS.

METHODS

After obtaining ethical approval and informed consent, a total of 26 prospectively selected patients with severe AS (13 women, mean age 81 ± 7 years) and 17 healthy controls (12 women, mean age 63 ± 6 years) underwent cardiac magnetic resonance (CMR) imaging on a clinical 3 T scanner. The CMR protocol included a native Modified Look-Locker (MOLLI) T1 mapping and a Gradient Spin Echo (GraSE) T2-mapping sequence in three short-axis slices and one long-axis view. After segmentation, myocardial T1 and T2 values were averaged over the entire myocardium. Statistical analysis was performed using Wilcoxon sum-rank test, Welch's independent t-test and Pearson's correlation coefficient.

RESULTS

Global native myocardial T1 was significantly increased in AS patients when compared to controls (1305 ± 39 vs. 1272 ± 21 ms, p = .005). Similarly, mean myocardial T2 was significantly elevated in AS patients (51 ± 4 vs. 46 ± 2 ms, p < .001) and showed a strong correlation with native T1 (r = .60, p < .001). An overlap was observed between T1 of both groups, whereas T2 discriminated nearly perfectly between the two groups (area under the curve in ROC analyses: 0.76 for T1, 0.87 for T2).

CONCLUSIONS

Patients with severe AS exhibit significantly elevated native myocardial T1, which has previously been shown to correlate with the amount of myocardial collagen. Adding to this evidence, the present study is the first to show that native T1 and T2 are both significantly elevated and correlated in AS patients, pointing towards a potential role of oedematous/inflammatory processes in the pathophysiology of myocardial remodelling associated with AS.

Exercise Hemodynamics After Aortic Valve Replacement for Severe Aortic Stenosis

BACKGROUND

Severe aortic stenosis (AS) is often accompanied by diastolic dysfunction. After aortic valve replacement (AVR), the left ventricle often undergoes considerable reverse remodeling. Despite this, diastolic dysfunction may persist after AVR. The aims of this study were to determine the incidence of elevated left ventricular (LV) filling pressure at rest and during exercise among patients with severe AS after AVR and to describe factors related to elevated LV filling pressure, especially its association with LV and left atrial remodeling and myocardial fibrosis.

METHODS

Thirty-seven patients undergoing AVR were included. Echocardiography, cardiac computed tomography, and magnetic resonance imaging were performed before AVR. An LV biopsy sample was obtained during AVR and analyzed for collagen fraction. One year after AVR, right heart catheterization with exercise was performed. A mean pulmonary capillary wedge pressure (PCWP) ≥ 28 mm Hg during exercise was considered elevated.

RESULTS

Twelve patients (32%) had elevated exercise PCWP 1 year after AVR. Exercise PCWP was highest among patients undergoing concomitant coronary artery bypass graft surgery (30 ± 7 vs 25 ± 6 mm Hg, P = .04) and among patients with preoperative stroke volume index < 35 mL/m² (28 ± 8 vs 23 ± 4 mm Hg, P < .05). Baseline LV ejection fraction was lower among patients with elevated PCWP (56 ± 8% vs 64 ± 8%, P = .01), and coronary calcium score was significantly higher (median 870 AU [interquartile range, 454-2,491 AU] vs 179 AU [interquartile range, 63-513 AU], P = .02). Conversely, exercise PCWP was not related to the presence of high LV wall mass or to the severity of AS. Among patients undergoing isolated AVR, there was a correlation between LV interstitial volume fraction and PCWP (r = 0.57, P = .01) and mean pulmonary artery pressure (r = 0.51, P = .03) during exercise.

CONCLUSIONS

Elevated filling pressure during exercise was seen in one third of patients after AVR in this population and was seen primarily among patients with coexisting ischemic heart disease or diffuse myocardial fibrosis but was unrelated to preoperative severity of AS and LV remodeling.

Impact of left ventricular remodelling patterns on outcomes in patients with aortic stenosis

Aims

The objective of this study was to examine the association between the different patterns of left ventricular (LV) remodelling/hypertrophy on all-cause and cardiovascular mortality in patients with aortic stenosis (AS).

Methods and results

In total, 747 consecutive patients (69 ± 14 years, 57% men) with AS and preserved LV ejection fraction were included in this study. According to LV mass index and relative wall thickness, patients were classified into four LV patterns: normal, concentric remodelling (CR), concentric hypertrophy (CH), and eccentric hypertrophy (EH). One hundred and sixteen patients (15%) had normal pattern, 66 (9%) had EH, 169 (23%) had CR, and 396 (53%) had CH. During a median follow-up of 6.4 years, 339 patients died (242 from cardiovascular causes). CH was associated with higher risk of all-cause mortality compared with the three other LV patterns (all P < 0.05). After multivariable adjustment, CH remained associated with higher risk of mortality (HR = 1.27, 95% CI 1.01-1.61, P = 0.046). There was a significant interaction (P < 0.05) between sex and CH with regards to the impact on mortality: CH was associated with worse outcome in women (P = 0.0001) but not in men (P = 0.22). In multivariable analysis, CH remained associated with higher risk of worse outcome in women (HR = 1.56, 95% CI 1.08-2.24, P = 0.018).

Conclusions

This study shows that CH was independently associated with increased risk of mortality in AS patients with preserved ejection fraction. This association was observed in women but not in men. The pattern of LV remodelling/hypertrophy should be integrated in the risk stratification process in patients with AS.

Alterations in Titin Properties and Myocardial Fibrosis Correlate With Clinical Phenotypes in Hemodynamic Subgroups of Severe Aortic Stenosis

•

The extent of myocardial fibrosis and the degree of isoform-expression and phosphorylation changes in cardiomyocyte titin were unknown in different hemodynamic subgroups of AS, including “paradoxical” low-flow, low-gradient AS with preserved ejection fraction.

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Hemodynamic subtypes of AS were found to exhibit increased cardiac fibrosis, titin-isoform transition toward more compliant N2BA variants, and both total and site-specific titin (N2Bus) hypophosphorylation compared with donor heart controls.

•

A significant shift toward N2BA titin appeared in “paradoxical” AS, whereas alterations in total-titin phosphorylation and cardiac fibrosis were similar in all hemodynamic subtypes of AS, suggesting increased myocardial passive stiffness.

•

The unfavorable prognosis of “paradoxical” AS could be explained by the pronounced myocardial remodeling, which is no less severe than in other AS subtypes.

Titin-isoform expression, titin phosphorylation, and myocardial fibrosis were studied in 30 patients with severe symptomatic aortic stenosis (AS). Patients were grouped into “classical” high-gradient, normal-flow AS with preserved ejection fraction (EF); “paradoxical” low-flow, low-gradient AS with preserved EF; and AS with reduced EF. Nonfailing donor hearts served as controls. AS was associated with increased fibrosis, titin-isoform switch toward compliant N2BA, and both total and site-specific titin hypophosphorylation compared with control hearts. All AS subtypes revealed titin and matrix alterations. The extent of myocardial remodeling in “paradoxical” AS was no less severe than in other AS subtypes, thus explaining the unfavorable prognosis.

Sex-Specific Considerations in Women with Aortic Stenosis and Outcomes After Transcatheter Aortic Valve Replacement

Aortic stenosis (AS) is the most common valvular disease in the elderly and is associated with poor outcomes. Transcatheter aortic valve replacement (TAVR) is an alternative to surgical aortic valve replacement (SAVR) in high-risk patients. Herein, we describe the gender-related differences in baseline characteristics and pathophysiologic response to severe AS, imaging considerations unique to females, and short- and long-term outcomes after TAVR. Women undergoing TAVR are older and frailer, have less cardiovascular comorbidities, smaller femoral artery size, better left ventricular systolic function, hypertrophied and small left ventricles leading to a higher incidence of paradoxical low-flow low-gradient AS, and a greater prevalence of porcelain aorta, smaller aortic annulus size, and lower coronary ostia heights. Imaging and histopathological data also suggests a sex-related myocardial response to pressure overload from AS. Women experience more vascular complications and blood transfusion requirements, serious procedural complications, and a greater incidence of stroke, but have better long-term outcomes than men. Patient-prosthesis mismatch, which is a concern in patients with a small aortic annulus size undergoing SAVR, has not been problematic with TAVR. The aforementioned findings suggest that TAVR may be preferable for women with severe AS. Further studies are warranted to directly compare TAVR with SAVR in women.

Native T1 and T2 mapping by cardiovascular magnetic resonance imaging in pressure overloaded left and right heart diseases

Background

Pulmonary arterial hypertension (PAH) and severe aortic valve stenosis (AS) are diseases characterized by increased afterload of the right and left heart, respectively. Our study aims to investigate the differences of myocardial tissue characteristics in the pressure overloaded left and right hearts, especially in the shared interventricular septum, as detected by native T1 and T2 relaxation times.

Methods

Eighteen patients with PAH and 19 patients with severe AS in addition to 5 healthy volunteers underwent 1.5-T CMR examination with native T1 and T2 mapping. Mean T1 and T2 value were measured at the right ventricular (RV) free wall, superior RV insertion, inferior RV insertion, interventricular septum and left ventricular (LV) lateral wall.

Results

Compared with controls and AS group, T1 was significantly elevated in the RV insertion in PAH group (P=0.015), while no statistically significant differences were seen in other segments among the three groups. There was an increase of T2 in the RV insertion in AS and PAH groups (P=0.01). Significant T2 elevation was also observed in the RV free wall of PAH group, and the LV lateral wall of AS group compared with the control group. RV insertion T2 was significantly correlated with RV end-diastolic volume index (r=0.608, P=0.016) and RV mass index (r=0.57, P=0.026) in the PAH group. LV lateral wall T2 and RV insertion T2 were significantly correlated with aortic valve mean gradients in the AS group (r=0.56, P=0.02; r=0.58, P=0.01, respectively).

Conclusions

In pressure overload diseases, both T1 and T2 values increase in the myocardium. The alterations seen in the RV insertion sites in the septum was more pronounced with RV pressure overload. T2 values also correlated with structural and functional remodeling in both diseases. Combining T1 and T2 mapping may help to better characterize the alternation of myocardial composition in pressure overloaded heart diseases.

[Results of aortic valve replacement in patients with aortic stenosis associated with severe left ventricular dysfunction]

The operative risk of aortic valve replacement (AVR) due to tight aortic stenosis (AS) associated with severe left ventricular dysfunction is high. Several risk factors for postoperative mortality have been described, but most of the reported case series are heterogeneous. This study aimed to analyze the postoperative results of AVR in patients with isolated tight AS associated with severe left ventricular dysfunction and to identify predictive factors of in-hospital mortality. We conducted a retrospective study of 46 patients with tight AS associated with severe left ventricular dysfunction who had undergone AVR. The average age was 59±12.70 years. 69.6% of patients were in NYHA Class III or IV. Mean EF was 32.3 ± 5.3%, and mean EuroScore was 12.20 ± 8.70. In-hospital mortality accounted for 15.20%. Morbidity was mainly marked by low cardiac output in 35% of cases. Multivariate logistic regression analysis showed that renal insufficiency (OR= 11.94, CI [2.65-72.22], p= 0.03) and congestive cardiac failure (OR= 25.33, CI [3.43-194.74], p= 0.009) were related to the risk of in-hospital mortality. Thirty-nine surviving patients were followed up for an average of 59.6± 21 months. Late mortality accounted for 5%. The functional status had significantly improved. EF increased, on average, by 5.5 units in early postoperative period and by 18 units in late postoperative period. In the long term, end-diastolic and end-systolic diameters were reduced by an average of 8 and 9 mm, respectively. The results of AVR due to tight AS associated with severe left ventricular dysfunction are satisfactory. Congestive heart failure and preoperative renal failure are the main risk factors for in-hospital mortality. Patient's outcome is marked by reduction in end-diastolic and end-systolic diameters of the left ventricle with improvement of the EF and of their functional status.

Relation of Left Atrial Size, Cardiac Morphology, and Clinical Outcome in Asymptomatic Aortic Stenosis

Left atrial (LA) dilation in asymptomatic severe aortic stenosis (AS) may be an indicator of advanced disease. We aimed to investigate the association between LA volume index and left ventricular (LV) morphology assessed with cardiac magnetic resonance imaging (cMRI), and to assess the association with cardiac events. Ninety-two asymptomatic patients with aortic valve area <1 cm², aortic peak jet velocity >3.5 m/s, and ejection fraction ≥50% were prospectively enrolled and divided according to echocardiographic-derived LA volume index  <35 ml/m². Patients underwent echocardiography, cMRI, exercise testing, and were followed for the composite end point of death, readmission, or aortic valve replacement. Aortic valve area index was similar (0.45 ± 0.08 cm²/m² vs 0.45 ± 0.09 cm²/m², p = 0.85) in patients with a dilated and normal LA. On cMRI patients with dilated LA were characterized by higher LV mass index (73 ± 17 g/m² vs 66 ± 16 g/m², p = 0.03), increased right ventricle (70 ± 14 ml/m² vs 63 ± 12 ml/m², p = 0.01) and LV end-diastolic volume index (84 ± 18 ml/m² vs 77 ± 16 ml/m², p = 0.05), and higher brain natriuretic peptide. Late enhancement pattern was similar. During follow-up 20 events were recorded in patients with LA dilation compared with 8 in patients with normal LA (adjusted hazard ratio 2.77, 95% confidence interval 1.19 to 6.46, p = 0.02); also B-type natriuretic peptide  >125 pg/ml was associated with adverse outcome (adjusted hazard ratio 3.63, 95% confidence interval interval 1.28 to 10.32, p = 0.02). LA dilation is associated with LV remodeling and provides prognostic information in severe asymptomatic AS.

Heart failure: a story of damage, fatigue and injury?

Heart failure has been recognised for years but the complete picture has been difficult to clearly understand. This article aims to try and put forward a proposed mechanistic explanation to encompass all that we see within the clinical heart failure syndrome using supporting published evidence. The aim of the article is to link, using published evidence, all the known varieties of heart failure into a spectrum that is explained by simple interlinked processes. In addition, the concept of routinely looking for reversibility of left ventricular dysfunction is introduced.

Aortic Stenosis, a Left Ventricular Disease: Insights from Advanced Imaging

Aortic stenosis (AS) is the most common primary valve disorder in the elderly with an increasing prevalence. It is increasingly clear that it is also a disease of the left ventricle (LV) rather than purely the aortic valve. The transition from left ventricular hypertrophy to fibrosis results in the eventual adverse effects on systolic and diastolic function. Appropriate selection of patients for aortic valve intervention is crucial, and current guidelines recommend aortic valve replacement in severe AS with symptoms or in asymptomatic patients with left ventricular ejection fraction (LVEF) <50 %. LVEF is not a sensitive marker and there are other parameters used in multimodality imaging techniques, including longitudinal strain, exercise stress echo and cardiac MRI that may assist in detecting subclinical and subtle LV dysfunction. These findings offer potentially better ways to evaluate patients, time surgery, predict recovery and potentially offer targets for specific therapies. This article outlines the pathophysiology behind the LV response to aortic stenosis and the role of advanced multimodality imaging in describing it.