Emerging medical treatments for aortic stenosis: statins, angiotensin converting enzyme inhibitors, or both?

Heart surgery over two decades: what we have learned about results and changing risks

OBJECTIVES

Using the cardiac surgery database is of high importance in referral centers and can lead to a better quality of care for patients. Tehran Heart Center (THC) is a cardiovascular referral center that was inaugurated in 2001. In this report, we aimed to present the third report of trends in patients' cardiovascular risk factors and surgical procedures from 2002 to 2021 that have been gathered for all THC patients.

METHODS

This serial cross-sectional study was conducted at Tehran Heart Center from 2002 to 2021. All patients undergoing cardiac surgeries were eligible to enter the study (N = 63,974). Those with miscellaneous types of surgeries were excluded (N = 9556). The distribution of cardiac surgeries (including isolated coronary artery bypass graft (CABG), isolated valve, and CABG + valve surgeries) and their respective in-hospital mortality were recorded. Furthermore, 20-year trends in the prevalence of various cardiovascular risk factors (CVRFs) among the following groups were evaluated: a) isolated CABG, b) aortic valve replacement/repair for aortic stenosis (AS/AVR/r), and c) isolated other valve surgeries (IVS).

RESULTS

A total of 54,418 patients (male: 70.7%, age: 62.7 ± 10.8 years) comprised the final study population, with 84.5% prevalence of isolated CABG. Overall, the AS/AVR/r group was in between the CABG and IVS groups concerning CVRFs distribution. Excluding some exceptions for the AS/AVR/r group (in which the small sample size (N = 909) precluded observing a clear trend), all studied CVRFs demonstrated an overall rising trend from 2002 to 2021 in all three groups. Regarding in-hospital mortality, the highest rate was recorded as 4.0% in 2020, while the lowest rate was 2.0% in 2001.

CONCLUSIONS

Isolated CABG remained the most frequent procedure in THC. Notable, increasing trends in CVRFs were observed during this 20-year period and across various types of cardiac surgeries, which highlights the clinical and policy-making implications of our findings.

All-cause and cardiovascular mortality in patients undergoing hemodialysis with aortic sclerosis and mild-to-moderate aortic stenosis: A cohort study

BACKGROUND AND AIMS

Mild-to-moderate aortic stenosis (AS) and aortic sclerosis, a precursor of AS, are associated with mortality in the general population; however, their association in patients undergoing hemodialysis with higher morbidity of AS is unknown. Thus, we investigated the mortality of aortic sclerosis and mild-to-moderate AS in patients undergoing hemodialysis.

METHODS

This was a retrospective multicenter cohort study of consecutive patients undergoing hemodialysis at nine dialysis facilities who underwent screening echocardiography between January 2008 and December 2019. We investigated the mortality of patients with aortic sclerosis or mild-to-moderate AS using multivariable Cox proportional hazards regression.

RESULTS

Among 1,878 patients undergoing hemodialysis, those with normal aortic valves, aortic sclerosis, mild AS, moderate AS, severe AS, and prosthetic aortic valves were 844 (45%), 793 (42%), 161 (8.6%), 38 (2.0%), 11 (0.6%), and 31 (1.7%), respectively. After excluding patients with severe AS and prosthetic aortic valves, we performed comparative analysis on 1,836 patients (mean age, 67 years; 66% male). In a median follow-up of 3.6 years, crude death rates (per 100 person-years) were 5.2, 10.6, and 13.0 in patients with normal aortic valves, aortic sclerosis, and mild-to-moderate AS, respectively. Compared with normal aortic valves, both aortic sclerosis and mild-to-moderate AS were associated with all-cause and cardiovascular death: adjusted hazard ratios (95% confidence intervals) were 1.36 (1.13-1.65) and 1.36 (1.02-1.80) for all-cause death; and 1.52 (1.06-2.17) and 1.74 (1.04-2.92) for cardiovascular death, respectively.

CONCLUSIONS

Aortic sclerosis and mild-to-moderate AS were independent risk factors for all-cause and cardiovascular death in patients undergoing hemodialysis.

Calcification and extracellular matrix dysregulation in human postmortem and surgical aortic valves

OBJECTIVES

Calcific aortic valve disease (CAVD) is a progressive disease ranging from aortic valve (AoV) sclerosis to AoV stenosis (AS), characterised by severe calcification with impaired leaflet function. Due to the lack of early symptoms, the pathological progression towards valve dysfunction is poorly understood. The early patterns of AoV calcification and altered extracellular matrix (ECM) organisation were analysed in individuals postmortem without clinical AS compared with clinical AS.

METHODS

Histological patterns of calcification and ECM organisation in postmortem AoV leaflets without clinical AS obtained from a tissue repository and surgical specimens obtained from individuals with clinical AS were compared with in vivo imaging prior to transcatheter AoV implantation.

RESULTS

AoV calcification was detected in all samples from individuals >50 years old, with severity increasing with age, independent of known CAVD risk factors. Two distinct types of calcification were identified: 'Intrinsic', primarily found at the leaflet hinge of postmortem leaflets, accompanied by abnormal collagen and proteoglycan deposition; and 'Nodular', extending from the middle to the tip regions in more severely affected postmortem leaflets and surgical specimens, associated with increased elastin fragmentation and loss of elastin integrity. Even in the absence of increased thickening, abnormalities in ECM composition were observed in postmortem leaflets without clinical AS and worsen in clinical AS.

CONCLUSIONS

Two distinct phenotypes of AoV calcification are apparent. While the 'nodular' form is recognised on in vivo imaging and is present with CAVD and valve dysfunction, it is unclear if the 'intrinsic' form is pathological or detected on in vivo imaging.

Hemodynamic characterization of aortic stenosis states

Aortic stenosis (AS) has become an increasingly prevalent clinical condition, as a result of the "greying of the population", the widespread application of sophisticated diagnostic tools including non-invasive imaging and invasive techniques, and the advent of minimally invasive surgical and percutaneous valve therapies. The diagnosis of severe AS traditionally has relied on the assessment of the mean transvalvular gradient (ΔP_mean ) and aortic valve area (AVA) by either echocardiography or catheterization. However, other hemodynamic variables as flow, pressure recovery, and jet eccentricity also play a major role in determining the final hemodynamic state of AS. Moreover, mismatch between ΔP_mean and AVA as in low flow low gradient AS and discordance between catheterization and echocardiographic studies in grading severity of AS have increased the complexity of AS diagnosis. The present case-based treatise emphasizes a multi-modality approach to delineation of the hemodynamic pathophysiology of different AS states. KEY POINTS: Reduction in the aortic valve area, flow across the aortic valve, and direction of the aortic stenosis jet determine the pressure gradient generated across the aortic valve in patients with aortic stenosis. Discordance between echo and catheterization maximum gradients is related to the inherent temporal differences between the times of their acquisition. Discordance between echo and catheterization mean gradients is related to pressure recovery and assumptions in the application of Bernoulli equation to estimate the aortic valve gradient. Pressure recovery relates to the ratio of the aortic valve area and ascending aortic diameter as well as the jet direction. Mismatch between area and gradient criteria for aortic stenosis severity may occur with or without concordance between echocardiographic and catheterization data. Errors of measurement should be excluded prior to assuming any mismatch or discordance between the data. Area gradient mismatch occurs when the aortic valve area is in the severe range, while the gradient is in the non-severe range as in low flow low gradient aortic stenosis. Reverse area gradient mismatch occurs when the gradient is in the severe range, while the aortic valve area is in the non-severe range as in congenital aortic stenosis with an eccentric jet.

I-κB kinase-ε knockout protects against angiotensin II induced aortic valve thickening in apolipoprotein E deficient mice

Aortic stenosis (AS) is considered to be an actively regulated progress that involves similar pathophysiological processes as atherosclerosis. I-κB kinase-ε (IKKε) is a proinflammatory molecule involved in atherosclerosis. The objective of the present study was to define the role of IKKε in pathological valvular remodeling. Aortic valves (AVs) from 52 patients undergoing AV replacement (AS) and 13 patients undergoing heart transplant (Control) were analyzed. ApoE^-/- mice (AK, n = 20) and ApoE^-/-IKKε^-/- mice (DK, n = 20) were generated and infused with saline or Ang II for 4 weeks. We found an upregulation of IKKε in human stenotic aortic valves compared to that in control AVs. Our results demonstrated that AK mice receiving AngII exhibited more advanced valvular remodeling and markedly increased IKKε expression. Conversely, loss of IKKε reduced adverse aortic valve thickening in response to Ang II, as measured by histological analyses. Furthermore, according to immunofluorescence analysis, Ang II resulted in obvious increases in the expression of α-SMA, TGF-β and NF-κB pathway components in the AK group, especially in the thickened area, while these increases were blocked in the DK group. Moreover, IKKε was co-expressed with α-SMA in valvular interstitial cells in ApoE^-/- mice after an AngII infusion. These data provide evidence that IKKε plays a key role in the development of valvular remodeling and that it may be a novel target for the treatment of AS.

End stage renal disease-induced hypercalcemia may promote aortic valve calcification via Annexin VI enrichment of valve interstitial cell derived-matrix vesicles

Patients with end‐stage renal disease (ESRD) have elevated circulating calcium (Ca) and phosphate (Pi), and exhibit accelerated progression of calcific aortic valve disease (CAVD). We hypothesized that matrix vesicles (MVs) initiate the calcification process in CAVD. Ca induced rat valve interstitial cells (VICs) calcification at 4.5 mM (16.4‐fold; p < 0.05) whereas Pi treatment alone had no effect. Ca (2.7 mM) and Pi (2.5 mM) synergistically induced calcium deposition (10.8‐fold; p < 0.001) in VICs. Ca treatment increased the mRNA of the osteogenic markers Msx2, Runx2, and Alpl (p < 0.01). MVs were harvested by ultracentrifugation from VICs cultured with control or calcification media (containing 2.7 mM Ca and 2.5 mM Pi) for 16 hr. Proteomics analysis revealed the marked enrichment of exosomal proteins, including CD9, CD63, LAMP‐1, and LAMP‐2 and a concomitant up‐regulation of the Annexin family of calcium‐binding proteins. Of particular note Annexin VI was shown to be enriched in calcifying VIC‐derived MVs (51.9‐fold; p < 0.05). Through bioinformatic analysis using Ingenuity Pathway Analysis (IPA), the up‐regulation of canonical signaling pathways relevant to cardiovascular function were identified in calcifying VIC‐derived MVs, including aldosterone, Rho kinase, and metal binding. Further studies using human calcified valve tissue revealed the co‐localization of Annexin VI with areas of MVs in the extracellular matrix by transmission electron microscopy (TEM). Together these findings highlight a critical role for VIC‐derived MVs in CAVD. Furthermore, we identify calcium as a key driver of aortic valve calcification, which may directly underpin the increased susceptibility of ESRD patients to accelerated development of CAVD.

Aberrant Glycosylation of Lumican in Aortic Valve Stenosis Revealed by Proteomic Analysis

To identify proteins related to the pathophysiology of aortic valve stenosis (AS), we investigated the protein profiles of AS aortic valves. Specifically, proteins were extracted from a thickened and calcified area (AS-C) and an apparently non-thickened and non-calcified area (AS-N) in an identical aortic valve leaflet in each of 6 AS patients. The proteins were then separated by 2-dimensional gel electrophoresis (2DE). Protein spots detected by 2DE were compared between the AS-C and AS-N samples. Protein spots of interest were subjected to protein identification by mass spectrometry.In total, 670 protein spots were detected by 2DE, 28 of which showed more than 1.5-fold different intensity (P < 0.05) between the AS-C and AS-N samples. Proteins were identified in 17 out of the 28 spots. Fibrinogen and lumican were identified in 9 and 3 spots, respectively. Intensity of these 12 spots was lower in the AS-C samples than in the AS-N samples. In the 1D-Western blot analysis, 4 lumican bands (80 kDa, 75 kDa, 65 kDa, and 53 kDa) were detected, of which 2 bands with 80 kDa and 75 kDa showed lower intensity in the AS-C samples than in the AS-N samples. When de-glycosylated protein samples were used in the 1D-Western blot, only a single lumican band with ~40 kDa was detected, indicating that lumican was variously glycosylated and that highly glycosylated lumican molecules were decreased in AS-C.Collectively, insufficient glycosylation of lumican in the thickened and calcified areas of AS aortic valves may be involved in the pathophysiology of AS.

The prevalence, incidence, progression, and risks of aortic valve sclerosis: a systematic review and meta-analysis

OBJECTIVES

The aim of this study was to comprehensively review the epidemiology of aortic sclerosis (ASc) and its association with cardiovascular events.

BACKGROUND

ASc, which is defined as thickening or calcification of the aortic valve without significant obstruction of blood flow, is a common finding on cardiac imaging.

METHODS

We searched MEDLINE and EMBASE from inception to April 2013 for studies describing the epidemiology of ASc and performed a meta-analysis of the risk of adverse events using a random effects model.

RESULTS

Twenty-two studies were identified from the systematic review. The prevalence of ASc increased in proportion to the average age of study participants, ranging from 9% in a study in which the mean age was 54 years to 42% in a study in which the mean age was 81 years. In total, 1.8% to 1.9% of participants with ASc had progression to clinical aortic stenosis per year. There was a 68% increased risk of coronary events in subjects with ASc (hazard ratio [HR]: 1.68; 95% confidence interval [CI]: 1.31 to 2.15), a 27% increased risk of stroke (HR: 1.27; 95% CI: 1.01 to 1.60), a 69% increased risk of cardiovascular mortality (HR: 1.69; 95% CI: 1.32 to 2.15), and a 36% increased risk of all-cause mortality (HR: 1.36; 95% CI: 1.17 to 1.59).

CONCLUSIONS

ASc is a common finding that is more prevalent with older age. Despite low rates of progression to ASc, there is an independent increase in morbidity and mortality associated with the condition.

Angiotensin II promotes aortic valve thickening independent of elevated blood pressure in apolipoprotein-E deficient mice

BACKGROUND

Valvular aortic stenosis (AS) is not an infrequent condition in the aged population. Activation of renin-angiotensin system (RAS) is presumed to be involved in the development of AS; however, direct evidence seems to be limited. We herein examined the effect of the administration of angiotensin II (Ang II) on the development of aortic valve thickening in apolipoprotein-E (ApoE)-deficient mice.

METHODS AND RESULTS

Male ApoE-deficient mice were divided into three groups: control (saline, n = 8), mice that were administered low-dose Ang II (500 ng/kg/min, n = 11), and those with high-dose Ang II (1000 ng/kg/min, n = 11) administration for 4 weeks. Administration of high-dose, but not low-dose, Ang II significantly induced aortic valve thickening. It was found that in the aortic valve leaflets of high-dose Ang II group, integrity of endothelial cells was impaired and the number of myofibroblasts was increased. These phenomena induced by high-dose Ang II were suppressed by Ang II type 1 receptor blocker olmesartan (n = 15), but not by the dilatator, hydralazine (n = 13). Olmesartan also suppressed dilatation of aortic diameter, although it did not significantly affect the plaque area, in the abdominal aorta in ApoE-deficient mice.

CONCLUSION

Administration of Ang II to genetically hyperlipidemic mice induced aortic valve thickening by a pressor-independent mechanism. Role of RAS activation in the development of AS in dyslipidemic patients should further be investigated.

Care of patients with apparently asymptomatic severe aortic valve stenosis

Although most asymptomatic patients with aortic stenosis (AS) have an excellent prognosis with observation only, some patients with severely stenotic aortic valves in the absence of symptoms may benefit from early intervention. In this article, we will review the literature on the use of varied imaging modalities, clinical factors, and biomarker testing to risk stratify such patients. Additionally, we will review the role of medical therapy to modify the course in AS.

Calcific aortic stenosis: a disease of the valve and the myocardium

Although aortic stenosis is a common condition associated with major morbidity, mortality, and health economic costs, there are currently no medical interventions capable of delaying or halting its progression. Re-evaluation of the underlying pathophysiology is therefore required so that novel therapeutic strategies can be developed. Aortic stenosis is characterized by progressive aortic valve narrowing and secondary left ventricular hypertrophy. Both processes are important because in combination they drive the development of symptoms and adverse events that characterize the latter stages of the disease. In this review, the authors examine the pathophysiology of aortic stenosis with respect to both the valve and the myocardium. In particular, the authors focus on the role of inflammation, fibrosis, and calcification in progressive valve narrowing and then examine the development of left ventricular hypertrophy, its subsequent decompensation, and the transition to heart failure. Finally the authors discuss potential therapeutic strategies on the basis of similarities aortic stenosis shares with other pathological conditions.

Regular exercise or changing diet does not influence aortic valve disease progression in LDLR deficient mice

Background

The development and progression of calcific aortic valve disease (CAVD) shares a number of similarities with atherosclerosis. Recently we could demonstrate that regular exercise training (ET) as primary prevention prevents aortic valve disease in LDL-receptor deficient (LDLR^−/−) mice. We aimed to investigate the impact of exercise training on the progression of CAVD in LDLR^−/− mice in the setting of secondary prevention

Methods and Results

Sixty-four LDLR^−/− mice were fed with high cholesterol diet to induce aortic valve sclerosis. Thereafter the animals were divided into 3 groups: group 1 continuing on high cholesterol diet, group 2 continuing with cholesterol diet plus 1 h ET per day, group 3 continuing with normal mouse chow. After another 16 weeks the animal were sacrificed. Histological analysis of the aortic valve thickness demonstrated no significant difference between the three groups (control 98.3±4.5 µm, ET 88.2±6.6 µm, change in diet 87.5±4.0). Immunohistochemical staining for endothelial cells revealed a disrupted endothelial cell layer to the same extend in all groups. Furthermore no difference between the groups was evident with respect to the expression of inflammatory, fibroblastic and osteoblastic markers.

Conclusion

Based on the present study we have to conclude that once the development of a CAVD is initiated, exercise training or a change in diet does not have the potential to attenuate the progress of the CAVD.

The effect of angiotensin-converting enzyme inhibitors and statins on the progression of aortic sclerosis and mortality

BACKGROUND AND AIM OF THE STUDY

Although aortic sclerosis has been associated with an increase in adverse cardiovascular outcomes, no proven therapy has been shown to slow its progression to overt aortic stenosis (AS). Thus, the hypothesis was assessed that treatment with angiotensin-converting enzyme inhibitors (ACE-Is), angiotensin receptor blockers (ARBs) or statins may be associated with an improvement in the clinical outcome of these patients.

METHODS

A total of 4,105 patients with evidence of aortic sclerosis seen on transthoracic echocardiography (defined as thickening or calcification with a mean valve gradient < or = 15 mmHg) was identified. Patients with a sclerotic valve who were treated with ACE-Is/ARBs or statins were followed for a mean period of 1,078 +/- 615 days. After adjustment for the propensity to receive ACE-Is/ARBs or statins, mortality, hemodynamic progression to AS, hospitalization for ischemic heart disease (IHD), and congestive heart failure (CHF) were assessed and related to the medical treatment.

RESULTS

At baseline, patients with aortic sclerosis who were treated with an ACE-I/ARB or a statin suffered significantly more from comorbidities such as IHD, CHF, hypertension, diabetes, and peripheral arterial disease, when compared to subjects with sclerotic valves not treated with these drugs. After adjustment for confounding factors, treatment with statins was associated with a significant reduction in mortality (odds ratio [OR] 0.73, 95% CI 0.56-0.98, p = 0.001), admission for IHD (OR 0.81, 95% CI 0.66-0.99, p = 0.03), admission for CHF (OR 0.68, 95% CI 0.55-0.85, p = 0.01) and progression to AS (OR 0.64, 95% CI 0.42-0.97, p = 0.03). While ACE-I treatment resulted in a significant reduction in admission for IHD (OR 0.80, 95% CI 0.65-0.98, p = 0.03) and CHF (OR 0.76, 95% CI 0.62-0.94, p = 0.01), the beneficial trend towards reduced mortality and delayed progression to AS was not significant.

CONCLUSION

Treatment of this patient population with statins led to a significant reduction in mortality and also slowed the progression to AS--an effect that was not statistically significant with ACE-I treatment.

Proteomic profile of human aortic stenosis: insights into the degenerative process

Degenerative aortic stenosis is the most common worldwide cause of valve replacement. While it shares certain risk factors with coronary artery disease, it is not delayed or reversed by reducing exposure to risk factors (e.g., therapies that lower lipids). Therefore, it is necessary to better understand its pathophysiology for preventive measures to be taken. In this work, aortic valve samples were collected from 20 patients that underwent aortic valve replacement (55% males, mean age of 74 years) and 20 normal control valves were obtained from necropsies (40% males, mean age of 69 years). The proteome of the samples was analyzed by quantitative differential electrophoresis (2D-DIGE) and mass spectrometry, and 35 protein species were clearly increased in aortic valves, including apolipoprotein AI, alpha-1-antitrypsin, serum albumin, lumican, alfa-1-glycoprotein, vimentin, superoxide dismutase Cu-Zn, serum amyloid P-component, glutathione S-transferase-P, fatty acid-binding protein, transthyretin, and fibrinogen gamma. By contrast, 8 protein species were decreased (transgelin, haptoglobin, glutathione peroxidase 3, HSP27, and calreticulin). All of the proteins identified play a significant role in cardiovascular processes, such as fibrosis, homeostasis, and coagulation. The significant changes observed in the abundance of key cardiovascular proteins strongly suggest that they can be involved in the pathogenesis of degenerative aortic stenosis. Further studies are warranted to better understand this process before we can attempt to modulate it.

Medical therapy for calcific aortic stenosis

Severe aortic stenosis due to calcification of the aortic valve is the most common indication for aortic valve replacement in the United States and Europe. The standard therapy for symptomatic patients with severe aortic stenosis is replacement of the valve. Some of the risk factors and pathophysiologic mechanisms in atherosclerosis play an important role in the development of calcific aortic stenosis. In the last few years, there have been an increased number of publications regarding the use of medications in order to delay the progression of aortic stenosis. These medications include statins, angiotensin-converting enzyme inhibitors, and biphosphanates. This article describes and summarizes some of the medical approaches that have emerged to alter the progression of aortic stenosis. Currently, only statins have been evaluated in randomized, placebo-control trials. Furthermore, statins have not proven to alter the progression of aortic stenosis. Ongoing randomized controlled trials with the use of angiotensin-converting enzyme inhibitors, statins, and biphosphonates will determine the use of these medications to delay the progression of aortic stenosis.

Circulating endothelial progenitor cells in patients with dysfunctional versus normally functioning congenitally bicuspid aortic valves

Patients with bicuspid aortic valve (BAV) may gradually develop significant valve dysfunction, whereas others remain free of dysfunction. Factors that determine the prognosis of BAV remain unclear. Because endothelial progenitor cells (EPCs) have a role in the repair of endothelial surfaces after injury, we hypothesized that EPCs may also be involved in preventing BAV degeneration. Accordingly, we compared EPC level and function in patients with BAV with versus without valve dysfunction. The study group included 22 patients with BAV and significant valve dysfunction (at least moderate aortic regurgitation and/or at least moderate aortic stenosis). The control group included 28 patients with BAV without valve dysfunction. All patients had 1 blood sample taken. Proportion of peripheral mononuclear cells expressing vascular endothelial growth factor receptor 2, CD133 and CD34 was evaluated by flow cytometry. EPC colony-forming units (CFUs) were grown from peripheral mononuclear cells, characterized, and counted after 7 days of culture. The 2 groups had similar clinical characteristics except for higher prevalence of hypertension in the dysfunctional valve group. Number of EPC CFUs was smaller in the dysfunctional valve group (32 CFUs/plate, 15 to 42.5, vs 48 CFUs/plate, 30 to 62.5, respectively, p = 0.01), and the migratory capacity of the cells in this group was decreased. In addition, the proportion of cells coexpressing vascular endothelial growth factor receptor 2, CD133, and CD34 tended to be smaller in the dysfunctional valve group. In conclusion, patients with BAV and significant valve dysfunction appear to have circulating EPCs with impaired functional properties. These findings require validation by further studies.

Modulating the nitric oxide - cyclic GMP pathway in the pressure-overloaded left ventricle and group II pulmonary hypertension

Group II pulmonary hypertension (PH) commonly occurs in the setting of a pressure-overloaded left ventricle (LV) which is also conducive to the development of heart failure with preserved ejection fraction. Population trends and a high prevalence of underlying causative conditions, such as essential hypertension or aortic stenosis, have increased the awareness of the pressure-overloaded LV and associated group II pulmonary hypertension. Patients often exhibit poor exercise tolerance and signs of heart failure indistinguishable from systolic heart failure; but effective medical treatments in this area have been lacking. Recent preclinical work has shed light on how the down-regulated nitric oxide - cyclic GMP pathway (within the myocardium and pulmonary vasculature) contributes to the pathophysiology of these associated conditions. This article will discuss the impact of the nitric oxide - cyclic GMP pathway on the pathogenesis of the pressure-overloaded LV and group II pulmonary hypertension, and will also introduce the potential therapeutic value of modulating this pathway.

Valvular aortic stenosis: a proteomic insight

Calcified aortic valve disease is a slowly progressive disorder that ranges from mild valve thickening with no obstruction of blood flow, known as aortic sclerosis, to severe calcification with impaired leaflet motion or aortic stenosis. In the present work we describe a rapid, reproducible and effective method to carry out proteomic analysis of stenotic human valves by conventional 2-DE and 2D-DIGE, minimizing the interference due to high calcium concentrations. Furthermore, the protocol permits the aortic stenosis proteome to be analysed, advancing our knowledge in this area.

SUMMARY

Until recently, aortic stenosis (AS) was considered a passive process secondary to calcium deposition in the aortic valves. However, it has recently been highlighted that the risk factors associated with the development of calcified AS in the elderly are similar to those of coronary artery disease. Furthermore, degenerative AS shares histological characteristics with atherosclerotic plaques, leading to the suggestion that calcified aortic valve disease is a chronic inflammatory process similar to atherosclerosis. Nevertheless, certain data does not fit with this theory making it necessary to further study this pathology. The aim of this study is to develop an effective protein extraction protocol for aortic stenosis valves such that proteomic analyses can be performed on these structures. In the present work we have defined a rapid, reproducible and effective method to extract proteins and that is compatible with 2-DE, 2D-DIGE and MS techniques. Defining the protein profile of this tissue is an important and challenging task that will help to understand the mechanisms of physiological/pathological processes in aortic stenosis valves.

Mechanisms of aortic valve calcification: the LDL-density-radius theory: a translation from cell signaling to physiology

Recent epidemiologic studies have revealed the risk factors associated for vascular atherosclerosis, including the male sex, smoking, hypertension, and elevated serum cholesterol, similar to the risk factors associated with the development of AV stenosis. An increasing number of models of experimental hypercholesterolemia demonstrate features of atherosclerosis in the AV, which are similar to the early stages of vascular atherosclerotic lesions. Experimental and clinical studies demonstrate that the hypercholesterolemic AV develops an atherosclerotic lesion which is proliferative and expresses high levels of osteoblast bone markers which mineralize over time to form bone. Calcification, the end-stage process of the disease, is necessary to understand as a prognostic indicator in the modification of this cellular process before it is too late. In summary, these findings suggest that medical therapies may have a potential role in patients in the early stages of this disease process to slow the progression to severe aortic stenosis and to delay the timing of the need for surgery. The translation of these experimental studies to clinical practice will be important to understand the potential for medical therapy for this disease process.

A randomized trial of the aldosterone-receptor antagonist eplerenone in asymptomatic moderate-severe aortic stenosis

BACKGROUND

The aim of the study is to determine whether the selective aldosterone-receptor antagonist eplerenone delays onset of left ventricular (LV) systolic dysfunction or reduces LV hypertrophy in asymptomatic patients with moderate to severe aortic stenosis. Effects of eplerenone on LV diastolic function and progression of valve stenosis were also evaluated.

METHODS

Sixty-five asymptomatic patients with a peak aortic valve velocity >3.0 m/s and normal LV function were randomized double blind to eplerenone, 100 mg daily (n = 33), or placebo (n = 32) for a median of 19 (interquartile range 15 to 25) months. Cardiac magnetic resonance imaging and echocardiography were performed and N-terminal pro-brain natriuretic peptide was measured at baseline and follow-up.

RESULTS

Symptomatic deterioration occurred in 13 subjects randomized to eplerenone and 11 to placebo (P = .34). Change in LV mass index (mean change +/- SD -0.3 +/- 14.6 vs +5.1 +/- 15 g/m(2) per year, P = .3), LV ejection fraction (+0.0% +/- 5.7% vs +0.8% +/- 5.7% per year, P = .9), and LV end-systolic volume index (-1.2 +/- 9 vs +0.04 +/- 12 mL/m(2) per year, P = .8) were small and similar for patients randomized to eplerenone and placebo, respectively. Decrease of aortic valve area (-0.11 +/- 0.22 vs -0.18 +/- 0.24 cm(2)/y, P = .2), worsening of LV diastolic dysfunction by echo-Doppler (E/E' +0.49 +/- 0.7 vs +1.32 +/- 2.0/year, P = .4), increase in the plasma level of N-terminal pro-brain natriuretic peptide (+63% vs +12% per year, P = .1), and decline in physical function score (9 +/- 34 vs 12 +/- 37/year, P = .7) were similar for subjects randomized to eplerenone and placebo, respectively.

CONCLUSIONS

In asymptomatic patients with moderate-severe aortic stenosis, eplerenone did not slow onset of LV systolic or diastolic dysfunction, decrease LV mass, or reduce progression of valve stenosis.

Optimum management of elderly patients with calcified aortic stenosis

Increased life-expectancy has led to a growing elderly population frequently presenting with aortic stenosis. This review focuses on the pathogenesis of calcific aortic stenosis, diagnosis and possible ways to halt the progression to severe symptomatic aortic stenosis, methods of assessing symptoms and severity, and modalities and timing of aortic valve replacement. At present the treatment of aortic stenosis for the majority of patients is surgical, and any patient with symptomatic severe aortic stenosis should be considered for aortic valve replacement. This article also discusses the role of emerging techniques of closed heart valve implantation either transfemoral or transapical, and which patients might be candidates for these new approaches to the treatment of aortic stenosis in the elderly population.

Evaluation and management of aortic valve and root disease

Aortic valve disease manifests in the form of stenosis, regurgitation, or some combination, yielding either excessive afterload and/or excessive preload on the left ventricle. Aortic root disease may affect valvular function, causing regurgitation; may simply be coexistent with stenotic aortic valvular disease; or may exist despite normal aortic valve function. Indications for intervening on aortic valve or root disease are determined by the presence of symptoms, by the pathology's impact on left ventricular function, or by the inherent risk of aortic catastrophe (dissection, disruption, or sudden death). Aortic valvular and root diseases are primarily treated by surgical replacement of the pathologic structures. Mechanical aortic valve replacement has long-term durability but requires continuous anticoagulation. Bioprostheses do not require anticoagulation but have more limited durability. Valve-sparing aortic root replacement and aortic valve repair offer the potential for indefinite durability without the need for anticoagulation but are technically more difficult to perform and require more stringent selection criteria based on determining the reparability of an aortic valve. Emerging percutaneous valve technologies offer new hope for patients who are not candidates for aortic valve surgery, but the applicability and durability of percutaneous aortic valves are not yet known. Timely and appropriate intervention in aortic valve and root disease can result in the restoration of a normal life span for patients with aortic valvular and/or root disease.

Risk factors for progression of calcific aortic stenosis and potential therapeutic targets

Current thought regarding the progression of calcific aortic stenosis (AS) is presented. After summarizing contemporary ideas about AS pathogenesis, the present article examines the factors that may affect disease progression. Data indicate that this process may be accelerated by aortic valve structure, degree of valvular calcification, chronic renal insufficiency and cardiovascular risk factors such as diabetes and dyslipidemia. Finally, the present review discusses potential therapeutic targets to slow AS progression.

An undiagnosed bicuspid aortic valve can result in severe left ventricular failure

Asymptomatic bicuspid aortic valves diagnosed in childhood need regular monitoring to allow early surgical intervention and prevention of left ventricular failure

Potential role of statin therapy in heart failure, atrial fibrillation and aortic stenosis

3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors, or statins, are widely prescribed throughout the world, and considerable evidence has indicated their powerful effects in ischemic forms of cardiovascular disease. Recently, several trials have demonstrated that statins have pleiotropic effects beyond their lipid-lowering capacities. These findings may play a role in the use of statins to manage forms of cardiovascular disease that may or may not have an ischemic etiology: congestive heart failure, atrial fibrillation and aortic stenosis.