Contemporary issues in severe aortic stenosis: review of current and future strategies from the Contemporary Outcomes after Surgery and Medical Treatment in Patients with Severe Aortic Stenosis registry

Electronic physician notification to facilitate the recognition and management of severe aortic stenosis: Rationale, design, and methods of the randomized controlled DETECT AS trial

BACKGROUND

Symptomatic severe aortic stenosis causes substantial morbidity and mortality when left untreated, yet recent data suggest its undertreatment.

OBJECTIVE

To evaluate the efficacy of electronic physician notification to facilitate the guideline-directed management of patients with severe aortic stenosis.

HYPOTHESIS

We hypothesize that patients with severe aortic stenosis who are in the care of physicians who receive the notification are more likely to undergo aortic valve replacement within one year.

METHODS/DESIGN

The Electronic Physician Notification to Facilitate the Recognition and Management of Severe Aortic Stenosis (DETECT AS) trial is a randomized controlled trial and quality improvement initiative designed to evaluate the efficacy of electronic provider notification versus usual clinical care in the management of patients with severe aortic stenosis. Providers ordering an echocardiogram with findings potentially indicative of severe aortic stenosis are randomized to receive electronic notification with customized guideline recommendations for the management of severe aortic stenosis or usual care (no notification). Randomization continues until 940 patients are enrolled.

SETTING

Multicentered, academic health system.

OUTCOMES

The primary endpoint is the proportion of patients with severe aortic stenosis receiving an aortic valve replacement within one year of the index echocardiogram. Secondary endpoints include mortality, heart failure hospitalization, transthoracic echocardiogram utilization, aortic stenosis billing code, and cardiology/Valve Team referral.

CONCLUSION

The DETECT AS trial will provide insight into whether electronic notification of providers on the presence of severe aortic stenosis and associated clinical guideline recommendations will facilitate recognition and guideline-directed management of severe aortic stenosis.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05230225, https://clinicaltrials.gov/ct2/show/NCT05230225.

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.

Novel Biomarkers and Advanced Cardiac Imaging in Aortic Stenosis: Old and New

Currently, the symptomatic status and left ventricular ejection fraction (LVEF) play a crucial role in aortic stenosis (AS) assessment. However, the symptoms are often subjective, and LVEF is not a sensitive marker of left ventricle (LV) decompensation. Over the past years, the cardiac structure and function research on AS has increased due to advanced imaging modalities and potential therapies. New imaging parameters emerged as predictors of disease progression in AS. LV global longitudinal strain has proved useful for risk stratification in asymptomatic severe AS patients with preserved LVEF. The assessment of myocardial fibrosis by cardiac magnetic resonance is the most studied application and offers prognostic information on AS. Moreover, the usage of biomarkers in AS as objective measures of LV decompensation has recently gained more interest. The present review focuses on the transition from compensatory LV hypertrophy (H) to LV dysfunction and the biomarkers associated with myocardial wall stress, fibrosis, and myocyte death. Moreover, we discuss the potential impact of non-invasive imaging parameters for optimizing the timing of aortic valve replacement and provide insight into novel biomarkers for possible prognostic use in AS. However, data from randomized clinical trials are necessary to define their utility in daily practice.

The Evolution of Pulmonary Hypertension and Its Prognostic Implications Post-TAVI-Single Center Experience

Background and Objectives: Since the first transcatheter aortic valve implantation (TAVI) procedure was performed in 2002, advances in technology and refinement of the method have led to its widespread use in patients with severe aortic stenosis (AS) and high surgical risk. We aim to identify the impact of TAVI on the clinical and functional status of patients with severe AS at the one-month follow-up and to identify potential predictors associated with the evolution of pulmonary hypertension (PH) in this category of patients. Materials and Methods: We conducted a prospective study which included 86 patients diagnosed with severe AS undergoing TAVI treatment. We analyzed demographics, clinical and echocardiographic parameters associated with AS and PH both at enrolment and at the 30-day follow-up. Results: In our study, the decrease of EUROSCORE II score (p < 0.001), improvement of angina (p < 0.001) and fatigue (p < 0.001) as clinical benefits as well as a reduction in NYHA functional class in patients with heart failure (p < 0.001) are prognostic predictors with statistical value. Regression of left ventricular hypertrophy (p = 0.001), increase in the left ventricle ejection fraction (p = 0.007) and improvement of diastolic dysfunction (p < 0.001) are echocardiographic parameters with a prognostic role in patients with severe AS undergoing TAVI. The pulmonary artery acceleration time (PAAT) (p < 0.001), tricuspid annular plane systolic excursion (TAPSE) (p = 0.020), pulmonary arterial systolic pressure (PASP) (p < 0.001) and the TAPSE/PASP ratio (p < 0.001) are statistically significant echocardiographic parameters in our study that assess both PH and its associated prognosis in patients undergoing TAVI. Conclusions: PAAT, TAPSE, PASP and the TAPSE/PASP ratio are independent predictors that allow the assessment of PH and its prognostic implications post-TAVI.

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

OBJECTIVES

The management of severe aortic stenosis mandates consideration of aortic valve intervention for symptomatic patients. However, for asymptomatic patients with severe aortic stenosis, recent randomised trials supported earlier intervention. We conducted a systematic review and meta-analysis to evaluate all the available data comparing the two management strategies.

METHODS

PubMed, Cochrane and Web of Science databases were systematically searched from inception until 10 January 2022. The search key terms were 'asymptomatic', 'severe aortic stenosis' and 'intervention'.

RESULTS

Meta-analysis of two published randomised trials, AVATAR and RECOVERY, included 302 patients and showed that early intervention resulted in 55% reduction in all-cause mortality (HR=0.45, 95% CI 0.24 to 0.86; I2 0%) and 79% reduction in risk of hospitalisation for heart failure (HR=0.21, 95% CI 0.05 to 0.96; I2 15%). There was no difference in risk of cardiovascular death between the two groups (HR=0.36, 95% CI 0.03 to 3.78; I2 78%). Additionally, meta-analysis of eight observational studies showed improved mortality in patients treated with early intervention (HR=0.38, 95% CI 0.26 to 0.56; I2 77%).

CONCLUSION

This meta-analysis provides evidence that, in patients with severe asymptomatic aortic stenosis, early intervention reduces all-cause mortality and improves outcomes compared with conservative management. While this is very encouraging, further randomised controlled studies are needed to draw firm conclusions and identify the optimal timing of intervention.

PROSPERO REGISTRATION NUMBER

CRD42022301037.

Rationale, Design, and Baseline Characteristics of the CURRENT AS Registry-2

BACKGROUND

There is scarce data evaluating the current practice pattern and clinical outcomes for patients with severe aortic stenosis (AS), including both those who underwent surgical aortic valve replacement (SAVR) or transcatheter aortic valve implantation (TAVI) and those who were managed conservatively in the TAVI era.Methods and Results: The Contemporary outcomes after sURgery and medical tREatmeNT in patients with severe Aortic Stenosis (CURRENT AS) Registry-2 is a prospective, physician-initiated, multicenter registry enrolling consecutive patients who were diagnosed with severe AS between April 2018 and December 2020 among 21 centers in Japan. The rationale for the prospective enrollment was to standardize the assessment of symptomatic status, echocardiographic evaluation, and other recommended diagnostic examinations such as computed tomography and measurement of B-type natriuretic peptide. Moreover, the schedule of clinical and echocardiographic follow up was prospectively defined and strongly recommended for patients who were managed conservatively. The entire study population consisted of 3,394 patients (mean age: 81.6 years and women: 60%). Etiology of AS was degenerative in 90% of patients. AS-related symptoms were present in 60% of patients; these were most often heart failure symptoms. The prevalence of high- and low-gradient AS was 58% and 42%, respectively, with classical and paradoxical low-flow low-gradient AS in 4.5% and 6.7%, respectively.

CONCLUSIONS

The CURRENT AS Registry-2 might be large and meticulous enough to determine the appropriate timing of intervention for patients with severe AS in contemporary clinical practice.

Prevalence and Outcomes of Low-Gradient Severe Aortic Stenosis-From the National Echo Database of Australia

Background

The prevalence and outcomes of the different subtypes of severe low‐gradient aortic stenosis (AS) in routine clinical cardiology practice have not been well characterized.

Methods and Results

Data were derived from the National Echocardiography Database of Australia. Of 192 060 adults (aged 62.8±17.8 [mean±SD] years) with native aortic valve profiling between 2000 and 2019, 12 013 (6.3%) had severe AS. Of these, 5601 patients (47%) had high‐gradient and 6412 patients (53%) had low‐gradient severe AS. The stroke volume index was documented in 2741 (42.7%) patients with low gradient; 1750 patients (64%) with low flow, low gradient (LFLG); and 991 patients with normal flow, low gradient. Of the patients with LFLG, 1570 (89.7%) had left ventricular ejection fraction recorded; 959 (61%) had paradoxical LFLG (preserved left ventricular ejection fraction), and 611 (39%) had classical LFLG (reduced left ventricular ejection fraction). All‐cause and cardiovascular‐related mortality were assessed in the 8162 patients with classifiable severe AS subtype during a mean±SD follow‐up of 88±45 months. Actual 1‐year and 5‐year all‐cause mortality rates varied across these groups and were 15.8% and 49.2% among patients with high‐gradient severe AS, 11.6% and 53.6% in patients with normal‐flow, low‐gradient severe AS, 16.9% and 58.8% in patients with paradoxical LFLG severe AS, and 30.5% and 72.9% in patients with classical LFLG severe AS. Compared with patients with high‐gradient severe AS, the 5‐year age‐adjusted and sex‐adjusted mortality risk hazard ratios were 0.94 (95% CI, 0.85–1.03) in patients with normal‐flow, low‐gradient severe AS; 1.01 (95% CI, 0.92–1.12) in patients with paradoxical LFLG severe AS; and 1.65 (95% CI, 1.48–1.84) in patients with classical LFLG severe AS.

Conclusions

Approximately half of those patients with echocardiographic features of severe AS in routine clinical practice have low‐gradient hemodynamics, which is associated with long‐term mortality comparable with or worse than high‐gradient severe AS. The poorest survival was associated with classical LFLG severe AS.

Timing of Intervention in Asymptomatic Aortic Stenosis

The decision to perform an intervention for asymptomatic severe aortic stenosis (AS) requires careful weighing of the risks of early intervention against those of watchful observation, and the optimal timing of intervention remains controversial. With improvements in surgical and postoperative care, long-term survival after surgical aortic valve (AV) replacement (AVR) is excellent in low-risk patients, and the emergence of transcatheter AVR may change the thresholds for early preemptive intervention, although a durability issue has to be resolved. A watchful observation strategy also has a risk of sudden death, irreversible myocardial damage, and increase in operative risk while waiting for symptoms to develop. We have been waiting for a prospective randomized trial to solve the intense debate between early AVR and watchful observation, and the RECOVERY (Randomized Comparison of Early Surgery versus Conventional Treatment in Very Severe Aortic Stenosis) trial provides the evidence to support early AVR for asymptomatic severe AS. Risk assessment with severity of AS and staging classification may help to facilitate the identification of patients who may benefit from early intervention. Based on the results of the RECOVERY trial, early surgical AVR is reasonable for asymptomatic patients with very severe AS (aortic jet velocity ≥4.5 m/s) and low surgical risk. Further evidence is required to extend the indications of surgical AVR and to consider transcatheter AVR in asymptomatic patients with severe AS.

Exercise Training for Patients With Severe Aortic Stenosis in a Convalescent Rehabilitation Ward - A Retrospective Cohort Study

Background: Exercise loading is contraindicated for patients with severe aortic stenosis (AS); however, everyday activities mandate the inclusion of a light load. The aim of this study was to investigate the efficacy and safety of exercise training for patients with severe AS who were admitted to a rehabilitation ward because of physical disability. Methods and Results: This historical cohort study was conducted at a single rehabilitation center in Japan. Patients admitted for rehabilitation of physical disability and those who met the definition of severe AS were analyzed. An exercise training program was implemented for patients with disability and severe AS. Cardiovascular symptoms during hospitalization were evaluated. Improvements in the performance of activities of daily living were assessed using the Functional Independence Measure (FIM). Eighteen patients undertook an exercise training program. The median patient age was 87 years (range 76-95 years). Of these patients, 3 died and another 3 were transferred to another hospital due to causes other than the exercise training program. None of the other patients experienced cardiovascular symptoms, and the FIM scores of 12 patients were significantly improved (median [range] scores at admission and discharge of 63 [32-88] and 87 [51-104], respectively; P<0.001). Conclusions: An exercise training program could be applied to patients with severe AS who were admitted for convalescent rehabilitation, because it can improve FIM scores.