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

A prospective analysis of the correlation between ultrasonic B-lines, cardiac tissue doppler signals and left ventricular end-diastolic pressure in patients with severe aortic stenosis

BACKGROUND

The development of heart failure is a turning point in the natural course of aortic stenosis (AS). Pulmonary oedema and elevated left ventricular pressure (LVP) are cardinal features of heart failure. Evaluating pulmonary oedema by lung ultrasound involves taking the upper hand with a bedside noninvasive tool that may reflect LVP.

AIM

We sought to assess the correlation between sonographic pulmonary congestion, invasive LV pre-A pressure, and echocardiographic LV end-diastolic pressure (LVEDP) in symptomatic AS patients receiving transcatheter aortic valve replacement.

METHODS

Forty-eight consecutive patients with severe AS and planned transcatheter aortic valve implantation (TAVI) were enrolled. LVEDP was estimated to be normal or elevated using the ASE/EACVI algorithm and transmitral Doppler indices, the E/A ratio, the E/e', and the left atrial volume index. Invasive LV pre-A pressure was used as a reference, with > 12 mm Hg defined as elevated.

RESULTS

Forty-eight patients (25 women (52%), mean age 75 years, standard deviation (SD) ± 7.7 years) were enrolled in the study. We detected severe B-lines (≥ 30) in 13 (27%) patients and moderate B-lines (15-30) in 33 (68.6%) patients. The number of B-lines increased significantly with the severity of New York Heart Association (NYHA) functional classes (Fig. 1). The B-line count was 14 ± 13 in NYHA class I patients, 20 ± 20 in class II patients, and 44 ± 35 in class III patients (p < 0.05, rho = 0.384). The number of B-lines was correlated with the E/E' ratio (R = 0.664, p < 0.0001) and the proBNP level (R = 0. 882, p < 0.008). We found no significant correlation with the LVEDP or LVEF. The LVEDP correlated well with the E/E' ratio (R = 0.491, p < 0.001) but not at all with E/A, DT, or LAVI. All patients had an elevated LVEDP > 12, with a mean pressure of 26 mmHg, a minimum of 13 mmHg, and a maximum of 45 mmHg, with an SD of 7.85.

CONCLUSION

Assessing lung ultrasonic B-lines is a straightforward and practical approach to identifying pulmonary oedema in AS patients. The number of B-lines correlated with the E/E' ratio and the functional status of patients but did not correlate with invasive LVEDP or LVEF. All patients had elevated LVEDP that correlated with E/E'.

2023 Korean Society of Echocardiography position paper for diagnosis and management of valvular heart disease, part I: aortic valve disease

This manuscript represents the official position of the Korean Society of Echocardiography on valvular heart diseases. This position paper focuses on the clinical management of valvular heart diseases with reference to the guidelines recently published by the American College of Cardiology/American Heart Association and the European Society of Cardiology. The committee tried to reflect the recently published results on the topic of valvular heart diseases and Korean data by a systematic literature search based on validity and relevance. In part I of this article, we will review and discuss the current position of aortic valve disease in Korea.

Predictors of Disease Progression and Adverse Clinical Outcomes in Patients With Moderate Aortic Stenosis Using an Artificial Intelligence-Based Software Platform

Patients with moderate aortic stenosis (AS) have a greater risk of adverse clinical outcomes than that of the general population. How this risk compares with those with severe AS, along with factors associated with outcomes and disease progression, is less clear. We analyzed serial echoes (from 2017 to 2019) from a single healthcare system using Tempus Next (Chicago, Illinois) software. AS severity was defined according to American Heart Association/American College of Cardiology guidelines. Outcomes of interest included death or heart failure hospitalization. We used Cox proportional hazards models and logistic regression to identify predictors of clinical outcome and disease progression, respectively. From 82,805 echoes for 61,546 patients, 1,770; 914; 565; and 1,463 patients had no, mild, moderate, or severe AS, respectively. Both patients with moderate and those with severe AS experienced a similar prevalence of adverse clinical outcomes (p = 0.45) that was significantly greater than that of patients without AS (p <0.01). In patients with moderate AS, atrial fibrillation (hazard ratio 3.29, 95% confidence interval 1.79 to 6.02, p <0.001) and end-stage renal disease (hazard ratio 3.34, 95% confidence interval 1.87 to 5.95, p <0.001) were associated with adverse clinical outcomes. One-third of patients with moderate AS with a subsequent echo (139/434) progressed to severe AS within 1 year. In conclusion, patients with moderate AS can progress rapidly to severe AS and experience a similar risk of adverse clinical outcomes; predictors include atrial fibrillation and low left ventricular ejection fraction. Machine learning algorithms may help identify these patients. Whether these patients may warrant earlier intervention merits further study.

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.

The Flow Rate in Patients With Low-Gradient Aortic Stenosis

PURPOSE

 The decision to assess the severity and determine the ideal timing of intervention for low-gradient aortic stenosis poses a greater challenge. Recently, a novel method for determining the flow status of patients with aortic stenosis has been introduced, utilizing flow rate measurements. In this study, we investigated whether the flow status of patients with low-gradient aortic stenosis is linked to mortality within a three-year timeframe.

METHODS

Twenty-nine patients diagnosed with low-gradient aortic stenosis and valve area ≤ 1 cm were identified during 2010-2015. Each patient's flow rate across the aortic valve was computed, and the study scrutinized echocardiographic parameters to ascertain their correlation with mortality over a three-year timeframe.

RESULTS

 We observed that among patients with low-gradient aortic stenosis and a valve area of ≤1 cm, a decreased flow rate across the aortic valve emerged as an independent predictor of mortality. A flow rate < 210 ml/s was linked with a three-year mortality rate of 66.7%, whereas a low stroke volume index < 35 ml/m² did not show an association with three-year mortality. This observation might be attributed to the smaller body sizes prevalent among these older patients, particularly females, which could influence the calculation of the stroke volume index.

CONCLUSION

 In older patients with low-gradient aortic stenosis, the flow rate can better reflect flow status than the stroke volume index, and it also suggests a prognostic significance in predicting mortality. Additional studies are warranted to validate these findings across broader patient populations and to assess the potential efficacy of early intervention strategies in this particular patient cohort.

Aortic valve replacement for moderate aortic stenosis during mitral surgery improves survival free from severe stenosis

BACKGROUND

Optimal management of moderate aortic stenosis during surgery for another indication is unclear. We assessed the effects of surgical aortic valve replacement for moderate aortic stenosis during mitral surgery.

METHODS

An institutional mitral surgery database was queried for patients with preoperative moderate aortic stenosis. Patients were stratified by whether they underwent concomitant surgical aortic valve replacement. Morbidity was analyzed using Student's t tests, Wilcoxon rank sum, chi-squared, and Fisher's exact tests. Survival was analyzed using Kaplan-Meier estimation and Cox regression.

RESULTS

Of 85 mitral surgery recipients with moderate aortic stenosis from 2012 to 2019, 62 (73%) underwent concomitant surgical aortic valve replacement. Surgical aortic valve replacement recipients were more likely to have bicuspid (11% vs. 0%, p  =  0.019) or rheumatic (18% vs. 0%, p  =  0.019) aortic valves, and to undergo mitral repair (32% vs. 9%, p  =  0.028). Groups did not differ with respect to mitral etiology, New York Heart Association class, or cardiac intervention history (p > 0.05). Postoperatively, groups had similar stroke and gastrointestinal bleed rates (3% vs. 0% and 2% vs. 0% in the surgical aortic valve replacement vs. no surgical aortic valve replacement group respectively, both p > 0.99). Five-year survival free from severe aortic stenosis was higher in the surgical aortic valve replacement group (66% vs. 17%, p  =  0.002). Surgical aortic valve replacement protected against the composite of death and progression to severe aortic stenosis at 5 years (hazard ratio: 0.32, p  =  0.003).

CONCLUSIONS

Surgical aortic valve replacement for moderate aortic stenosis at time of mitral surgery is a well-tolerated strategy to reduce aortic disease progression.

Enhanced detection of severe aortic stenosis via artificial intelligence: a clinical cohort study

OBJECTIVE

We developed an artificial intelligence decision support algorithm (AI-DSA) that uses routine echocardiographic measurements to identify severe aortic stenosis (AS) phenotypes associated with high mortality.

METHODS

631 824 individuals with 1.08 million echocardiograms were randomly spilt into two groups. Data from 442 276 individuals (70%) entered a Mixture Density Network (MDN) model to train an AI-DSA to predict an aortic valve area <1 cm², excluding all left ventricular outflow tract velocity or dimension measurements and then using the remainder of echocardiographic measurement data. The optimal probability threshold for severe AS detection was identified at the f1 score probability of 0.235. An automated feature also ensured detection of guideline-defined severe AS. The AI-DSA's performance was independently evaluated in 184 301 (30%) individuals.

RESULTS

The area under receiver operating characteristic curve for the AI-DSA to detect severe AS was 0.986 (95% CI 0.985 to 0.987) with 4622/88 199 (5.2%) individuals (79.0±11.9 years, 52.4% women) categorised as 'high-probability' severe AS. Of these, 3566 (77.2%) met guideline-defined severe AS. Compared with the AI-derived low-probability AS group (19.2% mortality), the age-adjusted and sex-adjusted OR for actual 5-year mortality was 2.41 (95% CI 2.13 to 2.73) in the high probability AS group (67.9% mortality)-5-year mortality being slightly higher in those with guideline-defined severe AS (69.1% vs 64.4%; age-adjusted and sex-adjusted OR 1.26 (95% CI 1.04 to 1.53), p=0.021).

CONCLUSIONS

An AI-DSA can identify the echocardiographic measurement characteristics of AS associated with poor survival (with not all cases guideline defined). Deployment of this tool in routine clinical practice could improve expedited identification of severe AS cases and more timely referral for therapy.

Counting the cost of premature mortality with progressively worse aortic stenosis in Australia: a clinical cohort study

BACKGROUND

Aortic stenosis is the most common cardiac valve disorder requiring clinical management. However, there is little evidence on the societal cost of progressive aortic stenosis. We sought to quantify the societal burden of premature mortality associated with progressively worse aortic stenosis.

METHODS

In this observational clinical cohort study, we examined echocardiograms on native aortic valves of 98 565 men and 99 357 women aged 65 years or older across 23 sites in Australia, from Jan 1, 2003, to Dec 31, 2017. Individuals were grouped according to their peak aortic valve velocity in 0·50 m/s increments up to 4·00 m/s or more (severe aortic stenosis), using 1·00-1·99 m/s (no aortic stenosis) as the reference group. Sex-specific premature mortality and years of life lost during a 5-year follow-up were calculated, along with willingness-to-pay to regain quality-adjusted life years (QALYs).

FINDINGS

Overall, 20 701 (21·0%) men and 18 576 (18·7%) women had evidence of mild-to-severe aortic stenosis. The actual 5-year mortality in men with normal aortic valves was 32·1% and in women was 26·1%, increasing to 40·9% (mild aortic stenosis) and 52·2% (severe aortic stenosis) in men and to 35·9% (mild aortic stenosis) and 55·3% (severe aortic stenosis) in women. Overall, the estimated societal cost of premature mortality associated with aortic stenosis was AU$629 million in men and $735 million in women. Per 1000 men and women investigated, aortic stenosis was associated with eight more premature deaths in men resulting in 32·5 more QALYs lost (societal cost of $1·40 million) and 12 more premature deaths in women resulting in 57·5 more QALYs lost (societal cost of $2·48 million) when compared with those without aortic stenosis.

INTERPRETATION

Any degree of aortic stenosis in older individuals is associated with premature mortality and QALYs. In this context, there is a crucial need for cost-effective strategies to promptly detect and optimally manage this common condition within our ageing populations.

FUNDING

Edwards LifeSciences, National Health and Medical Research Council of Australia, and the National Heart, Lung, and Blood Institute.

Engineering Efforts to Refine Compatibility and Duration of Aortic Valve Replacements: An Overview of Previous Expectations and New Promises

The absence of pharmacological treatments to reduce or retard the progression of cardiac valve diseases makes replacement with artificial prostheses (mechanical or bio-prosthetic) essential. Given the increasing incidence of cardiac valve pathologies, there is always a more stringent need for valve replacements that offer enhanced performance and durability. Unfortunately, surgical valve replacement with mechanical or biological substitutes still leads to disadvantages over time. In fact, mechanical valves require a lifetime anticoagulation therapy that leads to a rise in thromboembolic complications, while biological valves are still manufactured with non-living tissue, consisting of aldehyde-treated xenograft material (e.g., bovine pericardium) whose integration into the host fails in the mid- to long-term due to unresolved issues regarding immune-compatibility. While various solutions to these shortcomings are currently under scrutiny, the possibility to implant fully biologically compatible valve replacements remains elusive, at least for large-scale deployment. In this regard, the failure in translation of most of the designed tissue engineered heart valves (TEHVs) to a viable clinical solution has played a major role. In this review, we present a comprehensive overview of the TEHVs developed until now, and critically analyze their strengths and limitations emerging from basic research and clinical trials. Starting from these aspects, we will also discuss strategies currently under investigation to produce valve replacements endowed with a true ability to self-repair, remodel and regenerate. We will discuss these new developments not only considering the scientific/technical framework inherent to the design of novel valve prostheses, but also economical and regulatory aspects, which may be crucial for the success of these novel designs.

Lithotripsy of Calcified Aortic Valve Leaflets by a Novel Ultrasound Transcatheter-Based Device

The increasing incidence of calcific aortic valve disease necessitates the elaboration of new strategies to retard the progression of the pathology with an innovative solution. While the increasing diffusion of the transcatheter aortic valve replacements (TAVRs) allows a mini-invasive approach to aortic valve substitution as an alternative to conventional surgical replacement (SAVR) in an always larger patient population, TAVR implantation still has contraindications for young patients. In addition, it is liable to undergo calcification with the consequent necessity of re-intervention with conventional valve surgery or repeated implantation in the so-called TAVR-in-TAVR procedure. Inspired by applications for non-cardiac pathologies or for vascular decalcification before stenting (i.e., coronary lithotripsy), in the present study, we show the feasibility of human valve treatment with a mini-invasive device tailored to deliver shockwaves to the calcific leaflets. We provide evidence of efficient calcium deposit ruptures in human calcified leaflets treated ex vivo and the safety of the treatment in pigs. The use of this device could be helpful to perform shockwaves valvuloplasty as an option to retard TAVR/SAVR, or as a pretreatment to facilitate prosthesis implantation and minimize the occurrence of paravalvular leak.

Orthopaedic cardiac considerations in emergency

Orthopaedic patients undergoing emergency orthopaedic surgery should be referred for cardiac evaluation only when they are symptomatic or when a specific cardiac intervention is expected to reduce the surgical risk. A preoperative delay of 24-48 h of emergency orthopaedic operations has been associated with increased mortality and poor functional status of the patients. Research in the preoperative setting is almost exclusively retrospective because randomized studies are difficult to be performed and pose serious ethical concerns. Moreover, inevitably, guidelines have a low level of evidence and do not always provide a straightforward framework for the preoperative care of the patients. This editorial revisits the most common clinical cardiology dilemmas for emergency orthopaedic surgery to explore controversies of current recommendations and elaborate on the role of echocardiography in the perioperative period in emergency orthopaedic surgery.

Staging classification for cardiac damage associated with aortic stenosis

Okuno et al's staging classification of cardiac damage associated with aortic stenosis predicts prognosis following TAVI. More research is required, not only to further improve risk stratification, particularly at the higher and lower end of the risk spectrum, but also to assess the value of aortic valve intervention in such patient groups.