Early Surgery versus Watchful Waiting in Patients with Moderate Aortic Stenosis and Left Ventricular Systolic Dysfunction

Moderate aortic stenosis: Navigating the uncharted

Aortic stenosis (AS) stands as the most common valvular heart disease in developed countries and is characterized by progressive narrowing of the aortic valve orifice resulting in elevated transvalvular flow resistance, left ventricular hypertrophy, and progressive increased risk of heart failure and sudden death. This narrative review explores clinical challenges and evolving perspectives in moderate AS, where discrepancies between aortic valve area and pressure gradient measurements may pose diagnostic and therapeutic quandaries. Transthoracic echocardiography is the first-line imaging modality for AS evaluation, yet cases of discordance may require the application of ancillary noninvasive diagnostic modalities. This review underscores the importance of accurate grading of AS severity, especially in low-gradient phenotypes, emphasizing the need for vigilant follow-up. Current clinical guidelines primarily recommend aortic valve replacement for severe AS, potentially overlooking latent risks in moderate disease stages. The noninvasive multimodality imaging approach-including echocardiography, cardiac magnetic resonance, computed tomography, and nuclear techniques-provides unique insights into adaptive and maladaptive cardiac remodeling in AS and offers a promising avenue to deliver precise indications and exact timing for intervention in moderate AS phenotypes and asymptomatic patients, potentially improving long-term outcomes. Nevertheless, what we may have gleaned from a large amount of observational data is still insufficient to build a robust framework for clinical decision-making in moderate AS. Future research will prioritize randomized clinical trials designed to weigh the benefits and risks of preemptive aortic valve replacement in the management of moderate AS, as directed by specific imaging and nonimaging biomarkers.

Role of aortic valve replacement in moderate aortic stenosis: a 10-year outcomes study

OBJECTIVE

Patients with moderate aortic stenosis (AS) exhibit high morbidity and mortality. Limited evidence exists on the role of aortic valve replacement (AVR) in this patient population. To investigate the benefit of AVR in moderate AS on survival and left ventricular function.

METHODS

In a retrospective cohort study, patients with moderate AS between 2008 and 2016 were selected from the Cleveland Clinic echocardiography database and followed until 2018. Patients were classified as receiving AVR or managed medically (clinical surveillance). All-cause and cardiovascular mortality were assessed by survival analyses. Temporal haemodynamic and structural changes were assessed with longitudinal analyses using linear mixed effects models.

RESULTS

We included 1421 patients (mean age, 75.3±5.4 years and 39.9% women) followed over a median duration of 6 years. Patients in the AVR group had lower risk of all-cause (adjusted HR (aHR)=0.51, 95% CI: 0.34 to 0.77; p=0.001) and cardiovascular mortality (aHR=0.50, 95% CI: 0.31 to 0.80; p=0.004) compared with those in the clinical surveillance group irrespective of sex, receipt of other open-heart surgeries and underlying malignancy. These findings were seen only in those with preserved left ventricular ejection fraction (LVEF) ≥50%. Further, patients in the AVR group had a significant trend towards an increase in LVEF and a decrease in right ventricular systolic pressure compared with those in the clinical surveillance group.

CONCLUSIONS

In patients with moderate AS, AVR was associated with favourable clinical outcomes and left ventricular remodelling.

Early offering transcatheter aortic valve replacement to patients with moderate aortic stenosis: quantifying costs and benefits - a Markov model-based simulation study

OBJECTIVE

Aortic stenosis (AS) is one of the most common acquired cardiac valvular diseases. The success of transcatheter aortic valve implantation (TAVI) for severe AS has led to increasing interest in its use to earlier disease-moderate AS (MAS).

DESIGN

Model-based study using a Markov microsimulation technique to evaluate the long-term costs and benefits associated with 'early' TAVI. Key data inputs were sourced from the international literature and costs were obtained from Australian sources.

SETTING

Australian health care system perspective.

PARTICIPANTS

10 000 hypothetical MAS patients with or without left ventricular diastolic dysfunction or impaired left ventricular ejection fraction.

INTERVENTION

Comparing early TAVI to medical management over a life time horizon for MAS patients aged >65 years. We evaluated the cost-effectiveness of offering early TAVI in five scenarios (10%, 25%, 50%, 75% and 90% take-up rates).

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome measure is quality-adjusted life years (QALY) gained and the incremental cost-utility ratio (ICUR). Secondary outcomes are life-years gained and the number of heart failure case avoided.

RESULTS

Offering early TAVI for MAS patients resulted in both higher healthcare costs and greater benefits (an increase of 3.02 QALYs or 3.99 life-years) per person treated. The ICUR was around $A10 867 and $A11 926 per QALY gained for all five scenarios, with the total cost of early TAVI to the healthcare system being anticipated to be up to $A3.66 billion. Sensitivity analyses indicated a 100% probability of being cost-effective with a willingness to pay threshold of $A50 000/QALY. The benefits remained, even with assumptions of high levels of repeat valve replacement after TAVI.

CONCLUSION

While ongoing randomised controlled trials will define the benefit of TAVI to MAS patients, these results suggest that this intervention is likely to be cost-effective.

The impact of moderate aortic stenosis in acute myocardial infarction: A multicenter retrospective study

BACKGROUND

Aortic stenosis (AS) is associated with myocardial ischemia through different mechanisms and may impair coronary arterial flow. However, data on the impact of moderate AS in patients with acute myocardial infarction (MI) is limited.

AIMS

This study aimed to investigate the impact of moderate AS in patients presenting with acute myocardial infarction (MI).

METHODS

We conducted a retrospective analysis of all patients who presented with acute MI to all Mayo Clinic hospitals, using the Enterprise Mayo PCI Database from 2005 to 2016. Patients were stratified into two groups: moderate AS and mild/no AS. The primary outcome was all cause mortality.

RESULTS

The moderate AS group included 183 (13.3%) patients, and the mild/no AS group included 1190 (86.7%) patients. During hospitalization, there was no difference between both groups in mortality. Patients with moderate AS had higher in-hospital congestive heart failure (CHF) (8.2% vs. 4.4%, p = 0.025) compared with mild/no AS patients. At 1-year follow-up, patients with moderate AS had higher mortality (23.9% vs. 8.1%, p < 0.001) and higher CHF hospitalization (8.3% vs. 3.7%, p = 0.028). In multivariate analysis, moderate AS was associated with higher mortality at 1-year (odds ratio 2.4, 95% confidence interval [1.4-4.1], p = 0.002). In subgroup analyses, moderate AS increased all-cause mortality in STEMI and NSTEMI patients.

CONCLUSION

The presence of moderate AS in acute MI patients was associated with worse clinical outcomes during hospitalization and at 1-year follow-up. These unfavorable outcomes highlight the need for a close follow-up of these patients and for timely therapeutic strategies to best manage these coexisting conditions.

Natural history of moderate aortic stenosis and predictors for mortality: Systematic review and Meta-analysis

Although the current guidelines advocate imaging surveillance for moderate aortic stenosis (AS), recent studies suggest a worse prognosis associated with moderate AS than previously reported. Considering the recent paradigm shift in AS management, the risk/benefit profile of aortic valve replacement (AVR) for moderate AS needs to be re-evaluated. Herein, we conducted meta-analyses of natural history and risk predictors in patients with moderate AS. PubMed and EMBASE were searched through May 2022 to identify studies that investigated the natural history of patients with moderate AS. Meta-analyses with random effects model were conducted. Our analysis included 20 observational studies which enrolled a total of 11,114 patients with moderate AS. The rate of all-cause death was 11.0 [95 % confidence interval (CI), 7.6-14.4] per 100 patients per year. Surgical or transcatheter AVR occurred at a rate of 8.5 (95 % CI, 6.2-10.8; I², 98.9 %) per 100 patients per year. Occurrence of AVR during follow-up [hazard ratio (HR) (95 % CI) =0.56 (0.42-0.75), p < 0.001] and early AVR for moderate AS [HR (95 % CI) = 0.47 (0.25-0.90), p = 0.02] were associated with significantly lower all-cause mortality, while left ventricular ejection fraction <50 % [HR (95 % CI) =1.84 (1.33-2.57), p = 0.0003] and symptomatic status [HR (95 % CI) = 1.52 (1.32-1.75), p < 0.0001] were associated with increased all-cause mortality. Sex difference was not related to all-cause mortality. Our meta-analysis suggested that moderate AS was associated with high mortality, especially in low left ventricular systolic function or symptomatic patients. In addition, significant portion of the patients underwent AVR during follow-up.

Aortic valve replacement reduces mortality in moderate aortic stenosis: a systematic review and meta-analysis

BACKGROUND

With the introduction of transcatheter aortic valve replacement and an evolving understanding of the natural progression and history of aortic stenosis, the potential for earlier intervention in appropriate patients is promising; however, the benefit of aortic valve replacement in moderate aortic stenosis remains unclear.

METHODS

Pubmed, Embase, and the Cochrane Library databases were searched up until 30^th of December 2021 using keywords including moderate aortic stenosis and aortic valve replacement. Studies reporting all-cause mortality and outcomes in early aortic valve replacement (AVR) compared to conservative management in patients with moderate aortic stenosis were included. Hazard ratios were generated using random-effects meta-analysis to determine effect estimates.

RESULTS

3470 publications were screened with title and abstract review, which left 169 articles for full-text review. Of these studies, 7 met inclusion criteria and were included, totalling 4,827 patients. All studies treated AVR as a time-dependent co-variable in cox-regression multivariate analysis of all-cause mortality. Intervention with surgical or transcatheter AVR was associated with a 45% decreased risk of all-cause mortality (HR = 0.55 [0.42-0.68], I ² = 51.5%, P < 0.001). All studies were representative of the overall cohort with appropriate sample sizes, with no evidence of publication, detection, or information biases in any of the studies.

CONCLUSION

In this systematic review and meta-analysis, we report a 45% reduction in all-cause mortality in patients with moderate aortic stenosis who were treated with early aortic valve replacement compared to a strategy of conservative management. Randomised control trials are awaited to determine the utility of AVR in moderate aortic stenosis.

Managing Patients With Moderate Aortic Stenosis

Current guidelines recommend that clinical surveillance for patients with moderate aortic stenosis (AS) and aortic valve replacement (AVR) may be considered if there is an indication for coronary revascularization. Recent observational studies, however, have shown that moderate AS is associated with an increased risk of cardiovascular events and mortality. Whether the increased risk of adverse events is caused by associated comorbidities, or to the underlying moderate AS itself, is incompletely understood. Similarly, which patients with moderate AS need close follow-up or could potentially benefit from early AVR is also unknown. In this review, the authors provide a comprehensive overview of the current literature on moderate AS. They first provide an algorithm that helps to diagnose moderate AS correctly, especially when discordant grading is observed. Although the traditional focus of AS assessment has been on the valve, it is increasingly acknowledged that AS is not only a disease of the aortic valve but also of the ventricle. The authors therefore discuss how multimodality imaging can help to evaluate the left ventricular remodeling response and improve risk stratification in patients with moderate AS. Finally, they summarize current evidence on the management of moderate AS and highlight ongoing trials on AVR in moderate AS.

Aortic Stenosis: New Insights in Diagnosis, Treatment, and Prevention

Aortic stenosis (AS) is one of the most common valvular heart diseases and the number of patients with AS is expected to increase globally as the older population is growing fast. Since the majority of patients are elderly, AS is no longer a simple valvular heart disease of left ventricular outflow obstruction but is accompanied by other cardiac and comorbid conditions. Because of the significant variations of the disease, identifying patients at high risk and even earlier detection of patients with AS before developing symptomatic severe AS is becoming increasingly important. With the proven of efficacy and safety of transcatheter aortic valve replacement (TAVR) in the severe AS population, there is a growing interest in applying TAVR in those with less than severe AS. A medical therapy to reduce or prevent the progression in AS is actively investigated by several randomized control trials. In this review, we will summarize the most recent findings in AS and discuss potential future management strategies of patients with AS.

Impact of Moderate Aortic Stenosis on Long-Term Clinical Outcomes: A Systematic Review and Meta-Analysis

BACKGROUND

The clinical course of patients with moderate aortic stenosis (AS) remains incompletely defined.

OBJECTIVES

This study sought to analyze the clinical course of moderate AS and compare it with other stages of the disease.

METHODS

Multiple electronic databases were searched to identify studies on adult moderate AS. Random-effects models were used to derive pooled estimates. The primary endpoint was all-cause death. The secondary endpoints were cardiac death, heart failure, sudden death, and aortic valve replacement.

RESULTS

Among a total of 25 studies (12,143 moderate AS patients, 3.7 years of follow-up), pooled rates per 100 person-years were 9.0 (95% CI: 6.9 to 11.7) for all-cause death, 4.9 (95% CI: 3.1 to 7.5) for cardiac death, 3.9 (95% CI: 1.9 to 8.2) for heart failure, 1.1 (95% CI: 0.8 to 1.5) for sudden death, and 7.2 (95% CI: 4.3 to 12.2) for aortic valve replacement. Meta-regression analyses detected that diabetes (P = 0.019), coronary artery disease (P = 0.017), presence of symptoms (P < 0.001), and left ventricle (LV) dysfunction (P = 0.009) were associated with a significant impact on the overall estimate of all-cause death. All-cause mortality was higher in patients with reduced LV ejection fraction (<50%) than with normal LV ejection fraction: 16.5 (95% CI: 5.2 to 52.3) and 4.2 (95% CI: 1.4 to 12.8) per 100 person-years, respectively. Compared with moderate AS, the incidence rate difference of all-cause mortality was -3.9 (95% CI: -6.7 to -1.1) for no or mild AS and +2.2 (95% CI: +0.8 to +3.5) for severe AS patients.

CONCLUSIONS

Moderate AS appears to be associated with a mortality risk higher than no or mild AS but lower than severe AS, which increases in specific population subsets. The impact of early intervention in moderate AS patients having high-risk features deserves further investigation.

Economic Burden of Dementia Caused by Cardiovascular Disease in Australia

Background: The established link between cardiovascular disease (CVD) and dementia may provide new insights into dementia prevention. Objective: It aims to quantify the burden of dementia attributable to people with CVD. Methods: A Markov microsimulation model was developed to simulate the lifetime cost and quality-adjusted life-years (QALYs) related to people with and without CVD in Australia. A de-novo systematic review was undertaken to identify all evidence around the association between CVD [i.e., stroke, myocardial infarction (MI), atrial fibrillation (AF), and heart failure (HF)] and the risk of developing dementia. Incremental costs and QALY losses were estimated for people by type of CVD compared to the general Australian population without CVD. Results: Of the comprehensive literature search, 19 observational studies were included in the qualitative synthesis. Patients who had CVD incurred both higher healthcare costs over their lifetime (ranging from $73,131 for patients with AF to $127,396 for patients with HF) and fewer QALYs gains (from –1.099 for patients with MI to –5.163 for patients with stroke), compared to people who did not have CVD. The total incremental economic burden of dementia from patients aged 65 years and over with CVD was $6.45 billion (stroke), $11.89 billion (AF), $17.57 billion (MI), or $7.95 billion (HF) over their remaining life expectancy. Conclusion: The results highlighted the importance of CVD prevention to reduce the CVD burden and decrease the prevalence of dementia. Interventions that target patients with dementia risk factors like CVD may prove to be effective and cost-effective strategies.

The Association of Moderate Aortic Stenosis with Poor Survival is Modified by Age and Left Ventricular Function

BACKGROUND

Data on the independent association of moderate aortic stenosis (AS) with excess mortality, even when it does not progress to severe AS, is limited.

OBJECTIVE

To evaluate the association of moderate AS with poor survival and to identify clinically important modifiers of that association.

METHODS

Consecutive patients who underwent echocardiographic evaluation between 2007 and 2019. All-cause mortality and cancer data were available for all patients from national registries. Cox regression survival models were applied with censoring of patients who developed metastatic cancer, developed > moderate AS, or underwent aortic valve intervention during follow-up.

RESULTS

The study population included 92,622 patients. There were 2,202 (2%) patients with moderate AS, with a median age of 79 (IQR 70-85), of whom 1,254(57%) were men. During follow-up of 5 (IQR 3-8) years, 19,712 (21%) patients died. The cumulative probability of death at 5 years was higher for moderate AS patients (46% vs. 18% respectively, p Log-rank < .001). Propensity score matching analysis (N=2,896) that included clinical, laboratory, and echocardiographic predictors of poor survival demonstrated that compared with ≤ mild AS, patients with moderate AS were 17% more likely to die (95% CI 1.04-1.30, p = 0.007). Moreover, the model showed that the moderate AS associated risk was ejection fraction (EF) and age-dependent with a more pronounced association among non-octogenarian patients and patients with reduced EF (p for interaction .001 and .016 respectively).

CONCLUSION

Moderate AS is independently associated with excess mortality, even when it does not progress to severe AS. The associated risk is more pronounced among patients with reduced EF and patients younger than 80 years.

Moderate Aortic Stenosis: What is it and When Should We Intervene?

Current guidelines recommend aortic valve replacement in patients with severe aortic stenosis in the presence of symptoms or a left ventricular ejection fraction <50%. However, patients with less than severe aortic stenosis may also experience symptoms and recent literature suggests that the prognosis is not as benign as previously reported. There are no recommendations for patients with moderate aortic stenosis and left ventricular dysfunction, despite the high associated morbidity and mortality. There is also some evidence that these patients may benefit from early aortic valve intervention. It is recognised that aortic stenosis not only affects the valve but also has a complex myocardial response. This review discusses the natural history of moderate aortic stenosis along with the role of multimodality imaging in risk stratification in these patients.

Long-term Prognosis of Mild to Moderate Aortic Stenosis and Coronary Artery Disease

BACKGROUND

There is an incomplete understanding of the natural course of mild to moderate aortic stenosis (AS). We aimed to evaluate the natural course of patients with mild to moderate AS and its association with coronary artery disease (CAD).

METHODS

We retrospectively analyzed 787 patients diagnosed with mild to moderate AS using echocardiography between 2004 and 2010. Cardiac death and aortic valve replacement (AVR) for AS were assessed.

RESULTS

A median follow-up period was 92 months. Compared to the general population, patients with mild to moderate AS had a higher risk of cardiac death (hazard ratio [HR], 17.16; 95% confidence interval [CI], 13.65-21.59; P < 0.001). Established CAD was detected in 22.4% and associated with a significantly higher risk of cardiac mortality (adjusted HR, 1.62; 95% CI, 1.04-2.53; P = 0.033). The risk of cardiac death was lower when patients were taking statin (adjusted HR, 0.64; 95% CI, 0.41-0.98; P = 0.041), which was clear only after 7 years. Both patients with CAD and on statin tended to undergo more AVR, but the difference was not statistically significant (the presence of established CAD; adjusted HR, 1.63; 95% CI, 0.51-3.51; P = 0.214 and the use of statin; adjusted HR, 1.86; 95% CI, 0.76-4.58; P = 0.177).

CONCLUSION

Mild to moderate AS does not have a benign course. The presence of CAD and statin use may affect the long-term prognosis of patients with mild to moderate AS.