Effect of losartan versus atenolol on aortic valve sclerosis (a LIFE substudy)

Clinical impact of cardiovascular calcifications on stroke incidence in primary prevention: analysis in NADESICO study

The utility of assessment of cardiovascular calcifications for predicting stroke incidence remains unclear. This study assessed the relationship between cardiovascular calcifications including coronary artery calcification (CAC), aortic valve (AVC), and aortic root (ARC) assessed by coronary computed tomography (CT) and stroke incidence in patients with suspected CAD. In this multicenter prospective cohort study, 1187 patients suspected of CAD who underwent coronary CT were enrolled. Cardiovascular events including stroke were documented. Hazard ratio (HR) and confidence interval (CI) were assessed by Cox proportional hazard model adjusted for the Framingham risk score. C statistics for stroke incidence were also examined by models including cardiovascular calcifications. A total of 980 patients (mean age, 65 ± 7 years; females, 45.8%) were assessed by the CAC, AVC, and ARC Agatston scores. During a median follow-up of 4.0 years, 19 patients developed stroke. Cox proportional hazard model showed severe CAC (Agatston score ≥ 90th percentile [580.0 value]) and presence of AVC and ARC were associated with stroke incidence (HR; 10.33 [95% CI; 2.08-51.26], 3.08 [1.19-7.98], and 2.75 [1.03-7.30], respectively). C statistic in the model with CAC and AVC severity for predicting stroke incidence was 0.841 (95% CI; 0.761-0.920), which was superior to the model with CAC alone (0.762 [95% CI; 0.665-0.859], P < 0.01). CAC, AVC, and ARC were associated with stroke incidence in patients suspected of CAD. Assessment of both CAC and AVC may be useful for prediction of stroke incidence.

The Genetic Regulation of Aortic Valve Development and Calcific Disease

Heart valves are dynamic, highly organized structures required for unidirectional blood flow through the heart. Over an average lifetime, the valve leaflets or cusps open and close over a billion times, however in over 5 million Americans, leaflet function fails due to biomechanical insufficiency in response to wear-and-tear or pathological stimulus. Calcific aortic valve disease (CAVD) is the most common valve pathology and leads to stiffening of the cusp and narrowing of the aortic orifice leading to stenosis and insufficiency. At the cellular level, CAVD is characterized by valve endothelial cell dysfunction and osteoblast-like differentiation of valve interstitial cells. These processes are associated with dysregulation of several molecular pathways important for valve development including Notch, Sox9, Tgfβ, Bmp, Wnt, as well as additional epigenetic regulators. In this review, we discuss the multifactorial mechanisms that contribute to CAVD pathogenesis and the potential of targeting these for the development of novel, alternative therapeutics beyond surgical intervention.

Aortic valve calcification and risk of stroke: A systematic review and meta-analysis

Aortic valve calcification (AVC) is common among aged population and reported to be associated with the risk of stroke. However, the conclusions are inconsistent among studies. We performed a rigorous meta-analysis to unravel the AVC-stroke relationship. Embase, PubMed and Cochrane library were retrieved for related cohort studies investigating the correlations between AVC and risk of stroke. The language was limited to English. We selected risk ratio (RR) and 95% confidence intervals (CIs) as the effect size. Random-effects model was used in the data synthesis. A total of 7 cohort studies were identified in our meta-analysis with 21,395 participants and 1025 strokes. We detected statistically significant correlation between AVC and stroke (RR, 1.20; 95% CI, 1.02-1.40, P = 0.02) with low heterogeneity (I2 = 6.9%, P = 0.375). Statistically significant results were detected only in the subgroup of "+" degree of adjustment (P = 0.04). Therefore, a definite relationship between AVC and risk of stroke couldn't be decided based on current available data, and more large scale prospective studies were needed to verify the AVC-stroke relationship.

Observational and Genetic Associations of Resting Heart Rate With Aortic Valve Calcium

It is unknown if lifelong exposure to increased hemodynamic stress from an elevated resting heart rate (HR) may contribute to aortic valve calcium (AVC). We performed multivariate regression analyses using data from 1,266 Framingham Heart Study (FHS) Offspring cohort participants and 6,764 Multi-Ethnic Study of Atherosclerosis (MESA) participants. We constructed a genetic risk score (GRS) for HR using summary-level data in the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) AVC Consortium to investigate if there was evidence in favor of a causal relation. AVC was present in 39% of FHS Offspring cohort participants and in 13% of MESA cohort participants. In multivariate adjusted models, participants in the highest resting HR quartiles had significantly greater prevalence of AVC, with a prevalence ratio of 1.19 (95% confidence interval [CI] 0.99 to 1.44) for the FHS Offspring cohort and 1.32 (95% CI 1.12 to 1.63) for the MESA cohort, compared with those in the lowest quartile. There was a similar increase in the prevalence of AVC per standard deviation increase in resting HR in both FHS Offspring (prevalence ratio 1.08, 95% CI 1.01 to 1.15) and MESA (1.10, 95% CI 1.03 to 1.17). In contrast with these observational findings, a HR associated GRS was not significantly associated with AVC. Although our observational analysis indicates that a higher resting HR is associated with AVC, our genetic results do not support a causal relation. Unmeasured environmental and/or lifestyle factors associated with both increased resting HR and AVC that are not fully explained by covariates in our observational models may account for the association between resting HR and AVC.

Arterial hypertension and aortic valve stenosis: Shedding light on a common "liaison"

Arterial hypertension and aortic valve stenosis are common disorders and frequently present as concomitant diseases, especially in elderly patients. The impact of hypertension on heart haemodynamics is substantial, thus affecting the clinical presentation of any coexisting valvulopathy, especially of aortic stenosis. However, the interaction between these 2 entities is not thoroughly discussed in the European or/and American guidelines on the management of hypertension or/and valvular heart disease. The present review summarizes all available evidence on the potential interplay between hypertension and aortic valve stenosis, aiming to help physicians understand the pathophysiology and select the best diagnostic and therapeutic strategies (medical or/and interventional) for better management of these high-risk patients, taking into account the impact on outcome as well as the risk-benefit-ratio.

Potential drug targets for calcific aortic valve disease

Calcific aortic valve disease (CAVD) is a major contributor to cardiovascular morbidity and mortality and, given its association with age, the prevalence of CAVD is expected to continue to rise as global life expectancy increases. No drug strategies currently exist to prevent or treat CAVD. Given that valve replacement is the only available clinical option, patients often cope with a deteriorating quality of life until diminished valve function demands intervention. The recognition that CAVD results from active cellular mechanisms suggests that the underlying pathways might be targeted to treat the condition. However, no such therapeutic strategy has been successfully developed to date. One hope was that drugs already used to treat vascular complications might also improve CAVD outcomes, but the mechanisms of CAVD progression and the desired therapeutic outcomes are often different from those of vascular diseases. Therefore, we discuss the benchmarks that must be met by a CAVD treatment approach, and highlight advances in the understanding of CAVD mechanisms to identify potential novel therapeutic targets.

Is the degeneration of aortic valve bioprostheses similar to that of native aortic valves? Insights into valvular pathology

Aortic stenosis (AS) is the most common valvular disease requiring valve replacement with a prevalence of 2-4% in adults greater than or equal to 65 years of age. There is increasing evidence that AS is an active inflammatory process that is highly regulated, displaying multiple hallmarks of atherosclerosis. Clinically, the definite therapy of advanced AS is prosthetic valve replacement. Herein, bioprosthetic tissue valves (BPs) possess superior thromboresistant and hemodynamic properties compared with mechanical valves. However, cusp degeneration and calcification also limit their long-term outcome. The pathogenesis of BP calcification as well as that of native valves is still poorly understood. Recent studies suggest a similar valvular pathology, that underlies both types of valvular degeneration, but also an even more important role of inflammatory and repair processes in the case of BP degeneration.

The effect of aortic wall and aortic leaflet stiffening on coronary hemodynamic: a fluid-structure interaction study

Pathologies of the aortic valve such as aortic sclerosis are thought to impact coronary blood flow. Recent clinical investigations have observed simultaneous structural and hemodynamic variations in the aortic valve and coronary arteries due to regional pathologies of the aortic valve. The goal of the present study is to elucidate this observed and yet unexplained phenomenon, in which a local pathology in the aortic valve region could potentially lead to the initiation or progression of coronary artery disease. Results revealed a considerable impact on the coronary flow, velocity profile, and consequently shear stress due to an increase in the aortic wall or aortic leaflet stiffness and thickness which concur with clinical observations. The cutoff value of 0.75 for fractional flow reserve was reached when the values of leaflet thickness and aortic wall stiffness were approximately twice and three times their normal value, respectively. Variations observed in coronary velocity profiles as well as wall shear stress suggest a possible link for the initiation of coronary artery disease.

5-HT(2B) antagonism arrests non-canonical TGF-β1-induced valvular myofibroblast differentiation

Transforming growth factor-β1 (TGF-β1) induces myofibroblast activation of quiescent aortic valve interstitial cells (AVICs), a differentiation process implicated in calcific aortic valve disease (CAVD). The ubiquity of TGF-β1 signaling makes it difficult to target in a tissue specific manner; however, the serotonin 2B receptor (5-HT(2B)) is highly localized to cardiopulmonary tissues and agonism of this receptor displays pro-fibrotic effects in a TGF-β1-dependent manner. Therefore, we hypothesized that antagonism of 5-HT(2B) opposes TGF-β1-induced pathologic differentiation of AVICs and may offer a druggable target to prevent CAVD. To test this hypothesis, we assessed the interaction of 5-HT(2B) antagonism with canonical and non-canonical TGF-β1 pathways to inhibit TGF-β1-induced activation of isolated porcine AVICs in vitro. Here we show that AVIC activation and subsequent calcific nodule formation is completely mitigated by 5-HT(2B) antagonism. Interestingly, 5-HT(2B) antagonism does not inhibit canonical TGF-β1 signaling as identified by Smad3 phosphorylation and activation of a partial plasminogen activator inhibitor-1 promoter (PAI-1, a transcriptional target of Smad3), but prevents non-canonical p38 MAPK phosphorylation. It was initially suspected that 5-HT(2B) antagonism prevents Src tyrosine kinase phosphorylation; however, we found that this is not the case and time-lapse microscopy indicates that 5-HT(2B) antagonism prevents non-canonical TGF-β1 signaling by physically arresting Src tyrosine kinase. This study demonstrates the necessity of non-canonical TGF-β1 signaling in leading to pathologic AVIC differentiation. Moreover, we believe that the results of this study suggest 5-HT(2B) antagonism as a novel therapeutic approach for CAVD that merits further investigation.

Degenerative valve disease and bioprostheses: risk assessment, predictive diagnosis, personalised treatments

Aortic stenosis (AS) is the most frequent valvular heart disease. Severe AS results in concentric left ventricular hypertrophy, and ultimately, the heart dilates and fails. During a long period of time patients remain asymptomatic. In this period a pathology progression should be monitored and effectively thwarted by targeted measures. A cascade of cellular and molecular events leads to chronic degeneration of aortic valves. There are some molecular attributes characteristic for the process of valvular degeneration with clear functional link between shifted cell-cycle control, calcification and tissue remodelling of aortic valves. Bioactivity of implanted bioprosthesis is assumed to result in its dysfunction. Age, gender (females), smoking, Diabetes mellitus, and high cholesterol level dramatically shorten the re-operation time. Therefore, predictive and preventive measures would be highly beneficial, in particular for young female diabetes-predisposed patients. Molecular signature of valvular degeneration is reviewed here with emphases on clinical meaning, risk-assessment, predictive diagnosis, individualised treatments.

Established and emerging vascular risk factors and the development of aortic stenosis: an opportunity for prevention?

BACKGROUND

Aortic stenosis (AS) is the commonest valvular heart disease in the developed world. It is becoming increasingly accepted that the pathogenesis of AS and of its preceding abnormalities, aortic valve sclerosis (AVS) and aortic valve calcification (AVC), shares many characteristics with the atherosclerotic process.

OBJECTIVE

To assess the contribution of established and emerging vascular risk factors in the development of AS and to evaluate the potential of pharmacological intervention to modify the natural history of AS.

METHODS

We reviewed the epidemiological data that link AS and atherosclerosis and studies of vasculoprotective agents in patients with AS.

RESULTS/CONCLUSIONS

AS, AVS and AVC share many common risk factors with atherosclerosis and are possible markers of preclinical vascular disease. Statins appear to delay the progression of AS. However, more studies are needed before introducing such pharmacologic treatment for AS. The future may point towards targeted prevention of AS.

Aortic valve sclerosis: is it a cardiovascular risk factor or a cardiac disease marker?

BACKGROUND

Aortic valve sclerosis, without stenosis, has been associated with an increased cardiovascular mortality and morbidity due to myocardial infarction. However, it is unclear whether it is a cardiovascular risk factor or a cardiac disease marker. The goal of our study is to evaluate the difference in the prevalence of cardiovascular disease and risk factors among patients with or without aortic sclerosis.

METHODS

This observational study compared a group of 142 consecutive subjects with aortic valve sclerosis, assigned as group S, with a group of 101 subjects without aortic sclerosis, assigned as group C. Patients with bicuspid aortic valves and those with antegrade Doppler velocity across aortic valve leaflets exceeding 2.0 m/sec were excluded.

RESULTS

Mean ages of groups S and C were 71 +/- 8, and 68.8 +/- 6 years, respectively (P value = not significant). The prevalence of smoking, diabetes, hypercholesterolemia, hypertension, pulse pressure, left ventricular diastolic dysfunction, atrial fibrillation, and stroke was not significantly different between the two groups. However, there was a significantly higher prevalence of left ventricular hypertrophy (P = 0.05), ventricular arrhythmias (P = 0.02), myocardial infarction (P = 0.04), and systolic heart failure (P = 0.04) in aortic sclerosis group.

CONCLUSIONS

Aortic sclerosis is associated with a higher prevalence of left ventricular hypertrophy, ventricular arrhythmias, myocardial infarction, and systolic heart failure, while the prevalence of cardiovascular risk factors is not different between aortic sclerosis patients and controls. Hence, aortic sclerosis represents a cardiac disease marker useful for early identification of high-risk patients beyond cardiovascular risk factors rate.

Epidemiology and cardiovascular risk factors of aortic stenosis

The abnormalities of aortic valve morphology and function represent the most common cardiac-valve lesion particularly in elderly. The etiology of aortic stenosis is degenerative-calcific in the majority of patients. Many risk factors seems to be linked to the calcification and the stenosis of the aortic valve but they must be confirmed. In this review the etiology and the possible physiopathology of the aortic valve stenosis is discussed.

Aortic valve sclerosis is associated with preclinical cardiovascular disease in hypertensive adults: the Hypertension Genetic Epidemiology Network study

RATIONALE

Aortic valve sclerosis (AVS) has been associated with atherosclerosis and increased all-cause and cardiovascular death. However, whether AVS is associated with preclinical cardiovascular disease among adults at high risk because of hypertension has not been determined in a population-based sample.

METHODS AND RESULTS

Clinical and echocardiographic parameters were measured in 1624 hypertensive participants (54 +/- 11 years, 65% women, 63% black, 17% diabetic, 19% smokers) without significant valvular or cardiovascular diseases in the population-based Hypertension Genetic Epidemiology Network study. The 152 participants with AVS (9.4%), compared with participants without AVS, were older, more often white, male, treated for hypertension or hypercholesteromia (all P < 0.05) and had longer duration and worse hypertension, but did not differ in diabetes status, smoking or fenfluramine use. Adjusting for age, gender and race, the AVS group had higher total cholesterol/high-density lipoprotein-cholesterol (P < 0.05). Controlling for age, gender, race and other clinical covariates, AVS was independently associated with higher septal, posterior and relative wall thicknesses, isovolumic relaxation time and left atrial diameter, and with mild aortic regurgitation and mitral annular calcification (all P < 0.05).

CONCLUSIONS

In a population-based sample of hypertensive adults, AVS was prevalent (9.4%) and associated with a proatherogenic clinical profile and abnormal left ventricular geometry and filling, increased left atrial size and mitral annular calcification, which may contribute to the adverse prognosis associated with AVS.

Aortic sclerosis: not an innocent murmur but a marker of increased cardiovascular risk

The detection of an ejection systolic murmur in the aortic valve region often corresponds to a diagnosis of aortic sclerosis or minor disruption of the aortic valve with associated turbulence but minimal obstruction. Aortic sclerosis has two important clinical implications. Firstly, aortic sclerosis is an antecedent to clinically significant aortic valve obstruction and, secondly, it acts as a marker of increased risk of cardiovascular events. This article reviews the evidence that aortic sclerosis is a useful adjunctive tool in cardiovascular risk stratification and that its progression to haemodynamically significant aortic stenosis is a potential focus for individual monitoring and for interventional studies.