Management of asymptomatic severe aortic stenosis: a systematic review and meta-analysis

Prevalence of asymptomatic valvular heart disease in the elderly population: a community-based echocardiographic study

AIMS

With an ageing population, the presence of asymptomatic valvular heart disease (VHD) in the community remains unknown. The aim of this study is to determine the prevalence and associated factors of asymptomatic VHD in individuals ≥60 years old and to evaluate the feasibility of echocardiographic screening for VHD in this population.

METHODS AND RESULTS

This was a prospective cohort study conducted between 2007 and 2016 in the UK. Asymptomatic patients with no prior indication for echocardiography were invited to participate and evaluated with a health questionnaire, clinical examination, and transthoracic echocardiography. A total of 10,000 individuals were invited through their general practices. A total of 5429 volunteered to participate, of whom 4237 were eligible for inclusion. VHD was diagnosed in more than a quarter of patients (28.2%). The most common types of VHD were regurgitation of the tricuspid (13.8%), mitral (12.8%), and aortic (8.3%) valves (trivial regurgitation was not included). The rate of prevalence of clinically significant VHD was 2.4% (2.2% moderate and 0.2% severe), with mitral and aortic regurgitation being the most common. The only parameter associated with significant VHD was age (odds ratio 1.07 per 1 year increment, 95% confidence interval 1.05-1.09, P < 0.001). The number needed to scan to diagnose one clinically significant case of VHD is 42 for individuals ≥60 and 15 for those ≥75 years old.

CONCLUSION

Asymptomatic VHD is present in a significant proportion of otherwise healthy individuals without known VHD over 60 years old. Age is strongly associated with an increased incidence of significant VHD.

Natural history of initially asymptomatic severe aortic stenosis: a one-stage meta-analysis

BACKGROUND

Current guidelines on the management strategy for patients with asymptomatic severe aortic stenosis (AS) remain unclear. This uncertainty stems from the lack of data regarding the natural history of these patients. To address this gap, we performed a systematic review and meta-analysis examining the natural history of asymptomatic severe AS patients receiving conservative treatment.

METHODS

The PubMed, Cochrane, and Embase databases were searched from inception to 24 January 2024 using the keywords "asymptomatic" AND "aortic" AND "stenosis". We included studies examining patients with asymptomatic severe AS. In interventional trials, only data from conservatively managed arms were collected. A one-stage meta-analysis was conducted using individual patient data reconstructed from published Kaplan-Meier curves. Sensitivity analysis was performed for major adverse cardiovascular outcomes in patients who remained asymptomatic throughout follow-up.

RESULTS

A total of 46 studies were included (n = 9545). The median time to the development of symptoms was 1.11 years (95% CI 0.90-1.53). 49.36% (40.85-58.59) of patients who were asymptomatic had suffered a major adverse cardiovascular event by 5 years. The median event-free time for heart failure hospitalization (HFH) was 5.50 years (95% CI 5.14-5.91) with 36.34% (95% CI 33.34-39.41) of patients experiencing an HFH by year 5. By 5 years, 79.81% (95% CI 69.26-88.58) of patients developed symptoms (angina, dyspnoea, syncope and others) and 12.36% (95% CI 10.01-15.22) of patients died of cardiovascular causes. For all-cause mortality, the median survival time was 9.15 years (95% CI 8.50-9.96) with 39.43% (CI 33.41-36.40) of patients dying by 5 years. The median time to AVR was 4.77 years (95% CI 4.39-5.17), with 52.64% (95% CI 49.85-55.48) of patients requiring an AVR by 5 years.

CONCLUSION

Our results reveal poor cardiovascular outcomes for patients with asymptomatic severe AS on conservative treatment. A significant proportion eventually requires an AVR. Further research is needed to determine if early intervention with AVR is more effective than conservative treatment.

Impact of Stress Echocardiography on Aortic Valve Stenosis Management

Rest and stress echocardiography (SE) play a fundamental role in the evaluation of aortic valve stenosis (AS). According to the current guidelines for the echocardiographic evaluation of patients with aortic stenosis, four broad categories can be defined: high-gradient AS (mean gradient ≥ 40 mmHg, peak velocity ≥ 4 m/s, aortic valve area (AVA) ≤ 1 cm2 or indexed AVA ≤ 0.6 cm2/m2); low-flow, low-gradient AS with reduced ejection fraction (mean gradient < 40 mmHg, AVA ≤ 1 cm2, left ventricle ejection fraction (LVEF) < 50%, stroke volume index (Svi) ≤ 35 mL/m2); low-flow, low-gradient AS with preserved ejection fraction (mean gradient < 40 mmHg, AVA ≤ 1 cm2, LVEF ≥ 50%, SVi ≤ 35 mL/m2); and normal-flow, low-gradient AS with preserved ejection fraction (mean gradient < 40 mmHg, AVA ≤ 1 cm2, indexed AVA ≤ 0.6 cm2/m2, LVEF ≥ 50%, SVi > 35 mL/m2). Aortic valve replacement (AVR) is indicated with the onset of symptoms development or LVEF reduction. However, there is often mismatch between resting transthoracic echocardiography findings and patient's symptoms. In these discordant cases, SE and CT calcium scoring are among the indicated methods to guide the management decision making. Additionally, due to the increasing evidence that in asymptomatic severe aortic stenosis an early AVR instead of conservative treatment is associated with better outcomes, SE can help identify those that would benefit from an early AVR by revealing markers of poor prognosis. Low-flow, low-gradient AS represents a challenge both in diagnosis and in therapeutic management. Low-dose dobutamine SE is the recommended method to distinguish true-severe from pseudo-severe stenosis and assess the existence of flow (contractile) reserve to appropriately guide the need for intervention in these patients.

Asymptomatic Aortic Stenosis: From Risk Stratification to Treatment

Our understanding of the natural history of aortic stenosis has significantly increased over the last decade. There have been considerable advances in the diagnosis and risk stratification of patients with aortic stenosis and in surgical and anesthetic techniques. In addition, transcatheter aortic valve replacement has established itself as a viable alternative to surgical management. Inevitably, these developments have raised questions regarding the merits of waiting for symptom onset in asymptomatic patients with severe aortic stenosis before offering treatment. Recent observational and randomized trial data suggest that early intervention in asymptomatic patients with severe aortic stenosis and normal left ventricular function may confer a prognostic advantage to a watchful waiting strategy. In this review, we highlight advances in the management and risk stratification of patients with asymptomatic severe aortic stenosis with particular consideration of recent findings supporting early valvular intervention.

Left ventricular ejection fraction: clinical, pathophysiological, and technical limitations

Risk stratification of cardiovascular death and treatment strategies in patients with heart failure (HF), the optimal timing for valve replacement, and the selection of patients for implantable cardioverter defibrillators are based on an echocardiographic calculation of left ventricular ejection fraction (LVEF) in most guidelines. As a marker of systolic function, LVEF has important limitations being affected by loading conditions and cavity geometry, as well as image quality, thus impacting inter- and intra-observer measurement variability. LVEF is a product of shortening of the three components of myocardial fibres: longitudinal, circumferential, and oblique. It is therefore a marker of global ejection performance based on cavity volume changes, rather than directly reflecting myocardial contractile function, hence may be normal even when myofibril's systolic function is impaired. Sub-endocardial longitudinal fibers are the most sensitive layers to ischemia, so when dysfunctional, the circumferential fibers may compensate for it and maintain the overall LVEF. Likewise, in patients with HF, LVEF is used to stratify subgroups, an approach that has prognostic implications but without a direct relationship. HF is a dynamic disease that may worsen or improve over time according to the underlying pathology. Such dynamicity impacts LVEF and its use to guide treatment. The same applies to changes in LVEF following interventional procedures. In this review, we analyze the clinical, pathophysiological, and technical limitations of LVEF across a wide range of cardiovascular pathologies.

Prognostic Value of Cardiac Magnetic Resonance Feature Tracking Strain in Aortic Stenosis

BACKGROUND

Recent data have suggested that global longitudinal strain (GLS) could be useful for risk stratification of patients with severe aortic stenosis (AS). In this study, we aimed to investigate the prognostic role of GLS in patients with AS and also its incremental value in relation to left ventricular ejection fraction (LVEF) and late gadolinium enhancement (LGE).

METHODS

We analysed all consecutive patients with AS and LGE-CMR in our institution. Survival data were obtained from office of national statistics, a national body where all deaths in England are registered by law. Death certificates were obtained from the general register office.

RESULTS

Some 194 consecutive patients with aortic stenosis were investigated with CMR at baseline and followed up for 7.3 ± 4 years. On multivariate Cox regression analysis, only increasing age remained significant for both all-cause and cardiac mortality, while LGE (any pattern) retained significance for all-cause mortality and had a trend to significance for cardiac mortality. Kaplan-Meier survival analysis demonstrated that patients in the best and middle GLS tertiles had significantly better mortality compared to patients in the worst GLS tertiles. Importantly though, sequential Cox proportional-hazard analysis demonstrated that GLS did not have significant incremental prognostic value for all-cause mortality or cardiac mortality in addition to LVEF and LGE.

CONCLUSIONS

Our study has demonstrated that age and LGE but not GLS are significant poor prognostic indicators in patients with moderate and severe AS.

Systematic review and meta-analysis of early aortic valve replacement versus conservative therapy in patients with asymptomatic aortic valve stenosis with preserved left ventricle systolic function

BACKGROUND

A quarter of patients with severe aortic stenosis (AS) were asymptomatic, and only a third of them survived at the end of 4 years. Only a select subset of these patients was recommended for aortic valve replacement (AVR) by the current American College of Cardiology/American Heart Association guidelines. We intended to study the effect of early AVR (eAVR) in this subset of asymptomatic patients with preserved left ventricle function.

METHODS AND RESULTS

We searched PubMed and Embase for randomised and observational studies comparing the effect of eAVR versus conservative therapy in patients with severe, asymptomatic AS and normal left ventricular function. The primary outcome was all-cause mortality. The secondary outcomes were composite major adverse cardiac events (MACE) (study defined), myocardial infarction (MI), stroke, cardiac death, sudden death, the development of symptoms, heart failure hospitalisations and major bleeding. We used GRADEPro to assess the certainty of the evidence. In the randomised controlled trial (RCT) only analysis, we found no significant difference in all-cause mortality between the early aortic intervention group versus the conservative arm (CA) (incidence rate ratio, IRR (CI): 0.5 (0.2 to 1.1), I2=31%, p=0.09). However, in the overall cohort, we found mortality benefit for eAVR over CA (IRR (CI): 0.4 (0.3 to 0.7), I2=84%, p<0.01). There were significantly lower MACE, cardiac death, sudden death, development of symptoms and heart failure hospitalisations in the eAVR group. We noticed no difference in MI, stroke and major bleeding.

CONCLUSION

We conclude that there is no reduction in all-cause mortality in the eAVR arm in patients with asymptomatic AS with preserved ejection fraction. However, eAVR reduces heart failure related hospitalisations and death or heart failure hospitalisations.

PROSPERO REGISTRATION NUMBER

CRD42022306132.

Asymptomatic Severe and Moderate Aortic Stenosis: Time for Appraisal of Treatment Indications

Over the last decades, we have witnessed considerable improvements in diagnostics and risk stratification of patients with significant aortic stenosis (AS), paralleled by advances in operative and anesthetic techniques. In addition, accumulating evidence points to the potential benefit of early valve replacement in such patients prior to the onset of symptoms. In parallel, interventional randomized trials have proven the benefit of transcatheter aortic valve replacement in comparison to a surgical approach to valve replacement over a broad risk spectrum in symptomatic patients with AS. This article reviews contemporary management approaches and scrutinizes open questions regarding timing and mode of intervention in asymptomatic patients with severe AS. We also discuss the challenges surrounding the management of symptomatic patients with moderate AS as well as emerging dilemmas related to the concept of a life-long treatment strategy for patients with AS.

Early surgery vs conservative management among asymptomatic aortic stenosis: A systematic review and meta-analysis

•

Aortic valve replacement remains the definitive choice of treatment for AS.

•

All-cause mortality and adverse events are lower with early surgical valve repair.

•

In high-risk AS patients, early surgery is safer than conservative management.

•

Early intervention is crucial to prevent irreversible damage of AS.

Introduction

Although aortic valve replacement in severe symptomatic Aortic Stenosis (AS) are clearly outlined, the role of surgical intervention in asymptomatic severe AS remains unclear with limited evidence. The aim of our meta-analysis is to evaluate the efficacy and safety of early surgical aortic valve repair compared to conservative management.

Methods

A systematic literature search was performed in PubMed, Scopus, Embase and Cochrane databases for studies comparing the early surgery versus conservative management among asymptomatic aortic stenosis patients. Unadjusted odds ratios (OR) were pooled using a random-effect model, and a p-value of < 0.05 was considered statistically significant.

Results

A total of 5 articles (3 observational studies and 2 randomized controlled trials) were included. At a median followup of 4.1 years, here were significantly lower odds of all-cause mortality [OR = 0.30 (95 %CI:0.17–0.53), p < 0.0001], cardiovascular mortality [OR = 0.35 (95 %CI:(0.17–0.72), p = 0.005], and sudden cardiac death (OR = 0.36 (95 %CI: 0.15–0.89), p = 0.03) among early surgery group compared with conservative care. There was no significant difference between incidence of major bleeding, clinical thromboembolic events, hospitalization due to heart failure, stroke and myocardial infarction between the conservative care groups and early surgery.

Conclusion

Among asymptomatic patients with AS, early surgery shows better outcomes in reducing all-cause mortality and cardiovascular mortality compared with conservative management approaches.

Do all patients with asymptomatic severe aortic stenosis need treatment?

INTRODUCTION

Although guidelines recommend a watchful waiting strategy for patients with asymptomatic severe aortic stenosis, there have been considerable advancements in surgical and anaesthetic techniques along with the success of transcatheter aortic valve replacement (AVR) as a viable alternative to surgical AVR. Inevitably, these developments have raised questions as to whether or not there is still merit in waiting for symptoms to ensue before treatment may offered to these patients.

AREA COVERED

The principal purpose of this paper is to review the data supporting earlier intervention in patients with asymptomatic severe aortic stenosis, and to project the implications these and other ongoing trials will have on indications for AVR in asymptomatic patients in the future.

EXPERT OPINION

The threshold for intervention in certain subgroups of asymptomatic patients with severe AS has already been lowered. The next frontier will inevitably be determining whether all patients with severe AS should undergo AVR irrespective of their symptomatic status.