Effects of angiotensin converting enzyme inhibitors in hypertensive patients with aortic valve stenosis: a drug withdrawal study

The Complex Relationship between Hypoxia Signaling, Mitochondrial Dysfunction and Inflammation in Calcific Aortic Valve Disease: Insights from the Molecular Mechanisms to Therapeutic Approaches

Calcific aortic valve stenosis (CAVS) is among the most common causes of cardiovascular mortality in an aging population worldwide. The pathomechanisms of CAVS are such a complex and multifactorial process that researchers are still making progress to understand its physiopathology as well as the complex players involved in CAVS pathogenesis. Currently, there is no successful and effective treatment to prevent or slow down the disease. Surgical and transcatheter valve replacement represents the only option available for treating CAVS. Insufficient oxygen availability (hypoxia) has a critical role in the pathogenesis of almost all CVDs. This process is orchestrated by the hallmark transcription factor, hypoxia-inducible factor 1 alpha subunit (HIF-1α), which plays a pivotal role in regulating various target hypoxic genes and metabolic adaptations. Recent studies have shown a great deal of interest in understanding the contribution of HIF-1α in the pathogenesis of CAVS. However, it is deeply intertwined with other major contributors, including sustained inflammation and mitochondrial impairments, which are attributed primarily to CAVS. The present review aims to cover the latest understanding of the complex interplay effect of hypoxia signaling pathways, mitochondrial dysfunction, and inflammation in CAVS. We propose further hypotheses and interconnections on the complexity of these impacts in a perspective of better understanding the pathophysiology. These interplays will be examined considering recent studies that shall help us better dissect the molecular mechanism to enable the design and development of potential future therapeutic approaches that can prevent or slow down CAVS processes.

Current Evidence and Future Perspectives on Pharmacological Treatment of Calcific Aortic Valve Stenosis

Calcific aortic valve stenosis (CAVS), the most common heart valve disease, is characterized by the slow progressive fibro-calcific remodeling of the valve leaflets, leading to progressive obstruction to the blood flow. CAVS is an increasing health care burden and the development of an effective medical treatment is a major medical need. To date, no effective pharmacological therapies have proven to halt or delay its progression to the severe symptomatic stage and aortic valve replacement represents the only available option to improve clinical outcomes and to increase survival. In the present report, the current knowledge and latest advances in the medical management of patients with CAVS are summarized, placing emphasis on lipid-lowering agents, vasoactive drugs, and anti-calcific treatments. In addition, novel potential therapeutic targets recently identified and currently under investigation are reported.

Antihypertensive therapies in moderate or severe aortic stenosis: a systematic review and meta-analysis

BACKGROUND

Hypertension confers a poor prognosis in moderate or severe aortic stenosis (AS), however, antihypertensive therapy (AHT) is often not prescribed due to the perceived deleterious effects of vasodilation and negative inotropes.

OBJECTIVE

To assess the efficacy and safety outcomes of AHT in adults with moderate or severe AS.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and grey literature were searched without language restrictions up to 9 September 2019.

STUDY ELIGIBILITY CRITERIA, APPRAISAL AND SYNTHESIS METHODS

Two independent reviewers performed screening, data extraction and risk of bias assessments from a systematic search of observational studies and randomised controlled trials comparing AHT with a placebo or no AHT in adults with moderate or severe AS for any parameter of efficacy and safety outcomes. Conflicts were resolved by the third reviewer. Meta-analysis with pooled effect sizes using random-effects model, were estimated in R.

MAIN OUTCOME MEASURES

Mortality, Left Ventricular (LV) Mass Index, systolic blood pressure, diastolic blood pressure and LV ejection fraction RESULTS: From 3025 publications, 31 studies (26 500 patients) were included in the qualitative synthesis and 24 studies in the meta-analysis. AHT was not associated with mortality when all studies were pooled, but heterogeneity was substantial across studies. The effect size of AHT differed according to drug class. Renin-angiotensin-aldosterone system inhibitors (RAASi) were associated with reduced risk of mortality (Pooled HR 0.58, 95% CI 0.43 to 0.80, p=0.006), The differences in changes of haemodynamic or echocardiographic parameters from baseline with and without AHT did not reach statistical significance.

CONCLUSION

AHT appears safe, is well tolerated. RAASi were associated with clinical benefit in patients with moderate or severe AS.

Aortic Stenosis: What Risks Do the Stresses of Noncardiac Surgery or Pregnancy Pose and How Should They Be Managed?

Studies suggest that patients with aortic stenosis have increased risk in pregnancy and delivery and during anesthesia and surgery, although there are significant degrees of uncertainty as to the exact risks and best way to manage such patients. This article reviews current literature regarding impact of aortic stenosis on pregnancy and anesthesia during noncardiac surgery. There are shortcomings in the scientific evidence. Most of the available studies are observational and often retrospective and therefore there is a great deal of bias. This leads to difficulty in drawing conclusions in terms of how to apply the published information to clinical management.

Proteinuria is an independent predictor of rapid progression of mild to moderate aortic stenosis in patients with preserved renal function

Although proteinuria is a well-known risk factor for cardiovascular disease, its relationship with the progression of aortic stenosis (AS) has not been established. Our aim was to investigate the relationship between proteinuria (detected by urine dipstick test) and AS progression (assessed by the annualized reduction rate of aortic valve area [AVA]). A total of 460 patients with mild to moderate AS (defined by a peak velocity of 2.0-4.0 m/s) without end-stage renal disease who underwent two echocardiograms at least 3 months apart were included. The progression of AS was significantly faster in patients with proteinuria than those without (108 patients vs. 352 patients; annualized reduction rate of AVA, - 7.7 ± 13.5% vs. - 4.5 ± 11.6%; p = 0.017). The relationship between the presence of proteinuria and the accelerated progression of AS was significant among patients with estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73 m² (- 11.0 ± 17.5% vs. - 4.2 ± 10.0%; p < 0.001), but not among those with eGFR 15-60 mL/min/1.73 m² (- 5.8 ± 10.3 vs. - 5.3 ± 14.8%; p = 0.822). When stratified by the presence of diabetes, the association of proteinuria with AS progression was only significant in patients without diabetes (- 8.1 ± 12.0% vs. - 8.1 ± 15.7%; p = 0.018). Multivariable logistic regression analysis identified that the presence of proteinuria was an independent predictor of AS progression. The progression of AS was accelerated in patients with mild to moderate AS and proteinuria, particularly among those with preserved renal function and no diabetes.

Targeting vasoactive peptides for managing calcific aortic valve disease

Calcific aortic valve disease (CAVD) represents a spectrum of disease spanning from milder degrees of calcification of valve leaflets, i.e., aortic sclerosis, to severe calcification i.e., aortic stenosis (AS) with hemodynamic instability. The prevalence of CAVD is increasing rapidly due to the aging of the population, being up to 2.8% among patients over 75 years of age. Even without significant aortic valve stenosis, aortic sclerosis is associated with a 50% increased risk of myocardial infarction and death from cardiovascular causes. To date, there is no pharmacological treatment available to reverse or hinder the progression of CAVD. So far, the cholesterol-lowering therapies (statins) and renin-angiotensin system (RAS) blocking drugs have been the major pharmacological agents investigated for treatment of CAVD. Especially angiotensin receptor blockers (ARB)s and angiotensin convertase enzyme inhibitors (ACEI)s, have been under active investigation in clinical trials, but have proven to be unsuccessful in slowing the progression of CAVD. Several studies have suggested that other vasoactive hormones, including endothelin and apelin systems are also associated with development of AS. In the present review, we discuss the role of vasoactive factors in the pathogenesis of CAVD as novel pharmacological targets for the treatment of aortic valve calcification. Key messages Vasoactive factors are involved in the progression of calcific aortic valve disease. Endothelin and renin-angiotensin systems seem to be most prominent targets for therapeutic interventions in the view of valvular pathogenesis. Circulating vasoactive factors may provide targets for diagnostic tools of calcified aortic valve disease.

The feasibility and effect of deprescribing in older adults on mortality and health: a systematic review and meta-analysis

AIMS

Deprescribing is a suggested intervention to reverse the potential iatrogenic harms of inappropriate polypharmacy. The review aimed to determine whether or not deprescribing is a safe, effective and feasible intervention to modify mortality and health outcomes in older adults.

METHODS

Specified databases were searched from inception to February 2015. Two researchers independently screened all retrieved articles for inclusion, assessed study quality and extracted data. Data were pooled using RevMan v5.3. Eligible studies included those where older adults had at least one medication deprescribed. The primary outcome was mortality. Secondary outcomes were adverse drug withdrawal events, psychological and physical health outcomes, quality of life, and medication usage (e.g. successful deprescribing, number of medications prescribed, potentially inappropriate medication use).

RESULTS

A total of 132 papers met the inclusion criteria, which included 34 143 participants aged 73.8 ± 5.4 years. In nonrandomized studies, deprescribing polypharmacy was shown to significantly decrease mortality (OR 0.32, 95% CI: 0.17-0.60). However, this was not statistically significant in the randomized studies (OR 0.82, 95% CI 0.61-1.11). Subgroup analysis revealed patient-specific interventions to deprescribe demonstrated a significant reduction in mortality (OR 0.62, 95% CI 0.43-0.88). However, generalized educational programmes did not change mortality (OR 1.21, 95% CI 0.86-1.69).

CONCLUSIONS

Although nonrandomized data suggested that deprescribing reduces mortality, deprescribing was not shown to alter mortality in randomized studies. Mortality was significantly reduced when applying patient-specific interventions to deprescribe in randomized studies.

Depressed Systemic Arterial Compliance is Associated with the Severity of Heart Failure Symptoms in Moderate-to-Severe Aortic Stenosis: a Cross-Sectional Retrospective Study

BACKGROUND

Patients with aortic stenosis (AS) may develop heart failure even in the absence of severe valve stenosis. Our aim was to assess the contribution of systemic arterial properties and the global left ventricular afterload to graded heart failure symptoms in AS.

METHODS

We retrospectively reviewed medical records of 157 consecutive subjects (mean age, 71±10 years; 79 women and 78 men) hospitalized owing to moderate-to-severe degenerative AS. Exclusion criteria included more than mild aortic insufficiency or disease of another valve, atrial fibrillation, coronary artery disease, severe respiratory disease or anemia. Heart failure symptoms were graded by NYHA class at admission. Systemic arterial compliance (SAC) and valvulo-arterial impedance (Zva) were derived from routine echocardiography and blood pressure.

RESULTS

Sixty-one patients were asymptomatic, 49 presented mild (NYHA II) and 47 moderate-to-severe (NYHA III-IV) heart failure symptoms. Mild symptoms were associated with lower SAC and transvalvular gradients, while more severe exercise intolerance coincided with older age, lower systolic blood pressure, smaller aortic valve area and depressed ejection fraction. By multiple ordinal logistic regression, the severity of heart failure symptoms was related to older age, depressed ejection fraction and lower SAC. Each decrease in SAC by 0.1 ml/m² per mmHg was associated with an increased adjusted odds ratio (OR) of a patient being in one higher category of heart failure symptoms graded as no symptoms, mild exercise intolerance and advanced exercise intolerance (OR: 1.16 [95% CI, 1.01-1.35], P=0.045).

CONCLUSIONS

Depressed SAC may enhance exercise intolerance irrespective of stenosis severity or left ventricular systolic function in moderate-to-severe AS. This finding supports the importance of non-valvular factors for symptomatic status in AS.

Short-term hemodynamic effect of angiotensin-converting enzyme inhibition in patients with severe aortic stenosis: a placebo-controlled, randomized study

BACKGROUND

In patients with severe aortic stenosis (AS), treatment with angiotensin-converting enzyme inhibitors has previously been considered contraindicated. However, there is a lack of clinical evidence to confirm these potential hemodynamic risks and benefits.

METHODS

Forty-four patients with severe AS (aortic valve area <1 cm(2)) were randomized to treatment with trandolapril 22 mg daily/placebo (1:1). Right heart catheterization and echocardiography were performed at rest and during exercise at baseline and on day 3. Follow-up was performed before valve replacement or after a maximum of 8 weeks, when exercise echocardiography was repeated.

RESULTS

Compared with placebo, systolic blood pressure and systemic arterial compliance significantly changed at day 3 (-14 ± 11 vs -5 ± 13 mm Hg, P = .02, and 0.08 ± 0.16 vs -0.05 ± 0.86 mL/m(2) per mm Hg, P = .03, respectively). Changes in left ventricular end systolic volume (LVESV) was nonsignificant (-8 ± 9 vs -3 ± 11 mL, P = .17). At a median of 49 days of follow-up, changes in LVESV and N-terminal pro-brain natriuretic peptide were even lower revealing significant differences between the groups (-7.8 ± 2.6 vs -0.5 ± 2.5 mL, P = .04, and -19 ± 7 vs 0.8 ± 6 pmol/L, P = .04, respectively). No episodes of symptomatic hypotension were noted, and other hemodynamic parameters remained unchanged.

CONCLUSION

Angiotensin-converting enzyme inhibition in severe AS caused a decrease in LVESV and N-terminal pro-brain natriuretic peptide with other hemodynamic parameters preserved both at rest and during exercise implying hemodynamic improvement with left ventricular unloading.

Aortic valve stenosis and arterial hypertension: a synopsis in 2013

Systemic hypertension and aortic valve stenosis (AVS) are both age-related diseases. The pathophysiology of AVS shares some similarities with essential hypertension, which might be the link between the two diseases. Although AS is usually related with low blood pressure levels, approximately one third of patients with severe AS suffer from arterial hypertension, a percentage that can increase up to 50 % according some studies. This review will summarize various aspects regarding the prevalence the pathophysiology and the natural history of those two diseases that seems to be linked, as well as the effect of blood pressure and antihypertensive treatment on various echocardiographic parameters in patients with AVS.

Aortic valvular heart disease: Is there a place for angiotensin-converting-enzyme inhibitors?

Aortic valve disease (AVD) is the most common form of valvular heart disease in the western world. The only proven therapy for severe AVD is open aortic valve replacement, with trans-catheter aortic valve implantation emerging as a promising modality to treat severe aortic stenosis in a selected group of patients. AVD has a long asymptomatic phase with symptoms occurring late in the disease and once symptoms develop, prognosis is poor. There is a growing appreciation that aortic valvular heart disease incorporates a disease process that extends beyond the valve itself leading to an aortic valvular 'heart' disease. The renin-angiotensin system is known to modulate adverse left ventricular remodeling and myocardial fibrosis, which could be caused by increased load caused by the AVD. In this review, the authors explore evidence that suggest that drugs that target the renin-angiotensin system may have a potential therapeutic role in AVD.

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.

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.

The effects of arterial hypertension on aortic valve stenosis

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Impact of hypertension on left ventricular structure in patients with asymptomatic aortic valve stenosis (a SEAS substudy)

OBJECTIVE

Both hypertension and aortic valve stenosis induce left ventricular hypertrophy. However, less is known about the influence of concomitant hypertension on left ventricular structure in patients with aortic valve stenosis.

METHODS

Baseline Doppler echocardiography was performed in 1720 patients with asymptomatic aortic valve stenosis (peak transaortic velocity >or=2.5 m/s and <or=4.0 m/s) recruited in the Simvastatin and Ezetimibe in Aortic Stenosis study at 173 centers in seven European countries. Patients were grouped as normotensive (n = 482) or hypertensive (n = 1238) according to history of hypertension or clinic blood pressure greater than 140 mmHg systolic or greater than 90 mmHg diastolic at baseline visits.

RESULTS

Hypertensive patients were older, more obese, and included more women (all P < 0.05). Furthermore, the hypertensive group had higher wall thicknesses and left ventricular mass and higher prevalence of left ventricular hypertrophy (40 vs. 25%) and increased relative wall thickness (21 vs. 14%, both P < 0.01). On the basis of aortic valve area and energy loss the degree of aortic valve stenosis did not differ between the groups. In multivariate analysis, hypertension predicted higher left ventricular mass independent of other well known confounders including male sex, circumferential end-systolic stress, body mass index, aortic regurgitation, left ventricular ejection fraction and severity of aortic stenosis (multiple R = 0.30, P < 0.001).

CONCLUSION

In patients with asymptomatic aortic stenosis, concomitant hypertension significantly influences left ventricular geometry and is associated with higher left ventricular mass, relative wall thickness and higher prevalence of left ventricular hypertrophy.

The in vivo diagnosis of early-stage aortic valve sclerosis using magnetic resonance imaging in a rabbit model

PURPOSE

To use magnetic resonance imaging (MRI) to identify and monitor early aortic valve sclerosis (AVS) induced by cholesterol feeding in rabbits. AVS is a highly prevalent disease process, affecting more than 25% of the population over age 65. A major obstacle to early stage medical management of AVS has been the lack of an objective noninvasive technique to identify its presence and monitor its progress.

MATERIALS AND METHODS

Retrospectively gated CINE fast spoiled gradient echo (fSPGR) images of aortic valve cusps were collected at 3-month intervals starting at 6 months using a 1.5 T MR scanner interfaced with a customized surface radiofrequency coil. At 16 months a subset of animals was sacrificed and excised cusps were examined with both high frequency ultrasound (US) and histopathological techniques to validate the MRI method.

RESULTS

MR and US analysis identified significant thickening of diseased AV cusps when compared to control (P < 0.05). Histopathological analysis confirmed the presence of human-like AVS in diseased rabbit valves.

CONCLUSION

Early AVS, exemplified by increased valve thickness, can be identified in vivo using high-resolution MRI.

ACE inhibition attenuates uremia-induced aortic valve thickening in a novel mouse model

Background

We examined whether impaired renal function causes thickening of the aortic valve leaflets in hyperlipidemic apoE-knockout (apoE^-/-) mice, and whether the putative effect on the aortic valves could be prevented by inhibiting the angiotensin-converting enzyme (ACE) with enalapril.

Methods

Thickening of the aortic valve leaflets in apoE^-/- mice was induced by producing mild or moderate chronic renal failure resulting from unilateral nephrectomy (1/2 NX, n = 18) or subtotal nephrectomy (5/6 NX, n = 22), respectively. Additionally, the 5/6 NX mice were randomized to no treatment (n = 8) or enalapril treatment (n = 13). The maximal thickness of each leaflet was measured from histological sections of the aortic roots.

Results

Leaflet thickness was significantly greater in the 5/6 NX mice than in the 1/2 NX mice (P = 0.030) or the unoperated mice (P = 0.003). The 5/6 NX mice treated with enalapril had significantly thinner leaflets than did the untreated 5/6 NX mice (P = 0.014).

Conclusion

Moderate uremia causes thickening of the aortic valves in apoE^-/- mice, which can be attenuated by ACE inhibition. The nephrectomized apoE^-/- mouse constitutes a new model for investigating the mechanisms of uremia-induced aortic valve disease, and also provides an opportunity to study its pharmacologic prevention.

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.

Calcific aortic valve disease: imaging studies and therapeutic interventions

Echocardiography is the predominant imaging method used for patients with aortic valve disease because of its excellent diagnostic accuracy, high reproducibility and noninvasive nature. Cardiac catheterization is typically reserved for patients in whom the diagnosis remains unclear, those requiring coronary angiography prior to valve replacement, and in the setting of complex valve disease. Cardiac computed tomography (CT) has recently been applied as a research tool to quantify the amount of aortic valve calcium (AVC), which has served as a clinical end point in several medical therapy trials. Medical therapy for aortic valve disease remains an active area of clinical research. Multiple retrospective studies have shown a benefit for 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (HMG-CoA reductase inhibitors or statins) in reducing disease progression. However, two recently completed prospective, randomized trials yielded conflicting results. The data for using angiotensin converting enzyme (ACE) inhibitors are in the preliminary stages. This review will focus on imaging methods that are available for patients with aortic valve disease and summarize the recent trials that have evaluated medical therapy aimed to reduce progression of aortic valve disease.

Aortic valve stenosis: an active atheroinflammatory process

PURPOSE OF REVIEW

To summarize the current understanding of the pathobiology of aortic valve stenosis and portray the major advances in this field.

RECENT FINDINGS

Stenotic aortic valves are characterized by atherosclerosis-like lesions, consisting of activated inflammatory cells, including T lymphocytes, macrophages, and mast cells, and of lipid deposits, calcific nodules, and bone tissue. Active mediators of calcification and cells with osteoblast-like activity are present in diseased valves. Extracellular matrix remodeling, including collagen synthesis and elastin degradation by matrix metalloproteinases and cathepsins, contributes to leaflet stiffening. In experimental animals, hypercholesterolemia induces calcification and bone formation in aortic valves, which can be inhibited by statin treatment. The potential of statins to retard progression of aortic valve stenosis has also been recognized in clinical studies; however, further prospective trials are needed. Angiotensin II-forming enzymes are upregulated in stenotic valves. Angiotensin II may participate in profibrotic progression of aortic valve stenosis and may serve as a possible therapeutic target.

SUMMARY

Recent findings regarding the interaction of inflammatory cells, lipids, mediators of calcification, and renin-angiotensin system in stenotic valves support the current opinion of aortic valve stenosis being an actively regulated disease, potentially amenable to targeted molecular therapy. Evidence from prospective clinical studies is eagerly awaited.

Valvular Aortic Stenosis

Standard echocardiographic evaluation of aortic stenosis (AS) severity includes measurement of aortic velocity, mean transaortic pressure gradient, and continuity equation valve area. Although these measures are adequate for decision making in most patients, there is no single value that defines severe stenosis. Aortic stenosis affects not just the valve, but the entire vascular system, including the left ventricle (LV) and systemic vasculature. More sophisticated measures of disease severity might explain the apparent overlap in hemodynamic severity between symptomatic and asymptomatic patients and might better predict the optimal timing of valve replacement. There have been several approaches to evaluation of stenosis severity based on valve hemodynamics, the ventricular response to increased afterload, ventricular-vascular coupling, or the systemic functional consequences of valve obstruction, such as exercise testing and serum brain natriuretic peptide levels. Aortic valve replacement is indicated when symptoms due to severe AS are present. In most asymptomatic patients, the risk of surgery is greater than the risk of watchful waiting so that management includes patient education, periodic echocardiography, and cardiac risk factor modification. Many adults with AS have comorbid conditions that affect both the diagnosis and management of the valve disease, including aortic regurgitation, aortic root dilation, hypertension, coronary artery disease, LV dysfunction, and atrial fibrillation. Comorbid conditions should be evaluated and treated based on established guidelines, although awareness of the potential effects of therapy in the presence of valve obstruction is needed.

Are angiotensin converting enzyme inhibitors beneficial in patients with aortic stenosis?

Angiotensin converting enzyme (ACE) inhibitors may become an accepted form of treatment for aortic stenosis in the future.