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

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.

Transcatheter Aortic Valve Replacement Improves Quality of Life and Ventricular Function With Low-Flow/Low-Gradient Aortic Stenosis

Background

D2 aortic stenosis (AS) is the highest risk AS subtype with worse operative and mortality outcomes. This study aimed to investigate the quality of life (QoL) and left ventricular ejection fraction (LVEF) in patients with classic (D2 subtype) low-flow/low-gradient AS who underwent transcatheter aortic valve replacement (TAVR).

Methods

In total, 634 patients with severe AS underwent TAVR at our institution from 2014 to 2020, of whom 76 met criteria for classic D2 AS with reduced LVEF. Echocardiographic and clinical outcomes including mortality, stroke, pacemaker placement (PPM), and readmission at baseline were compared with those at 30 days and 1 year. QoL data were extracted from the Kansas City Cardiomyopathy Questionnaire (KCCQ-12).

Results

The average baseline Society of Thoracic Surgeons risk score for patients with D2 AS was 7.66 ± 6.76. Patients with D2 AS reported improved QoL post-TAVR. The average baseline KCCQ-12 score was 39.5 ± 20, with improvement to 68.9 ± 20.6 at 30 days (P < .01) and 74.9 ± 17.5 at 1 year (P < .01). Mortality was 0% at 30 days and 18.4% at 1 year. The average baseline LVEF was 36.1 ± 9.4. Left ventricular function improved to 43.5 ± 12.9 (P <.001) at 30 days and 46.3 ± 11.2 (P = .03) at 1 year. Complications post-TAVR at 30 days included stroke (1.3%) and PPM (11.8%). Patients with D2 AS exhibited higher baseline conduction defects including atrial fibrillation and higher postoperative PPM than those with other subtypes.

Conclusions

Patients with D2 AS had significantly improved LVEF and QoL following TAVR at 30 days and 1 year. Postoperative rates of new PPM were higher than other subtypes, while stroke, dialysis, and mortality were lower than expected, supporting the benefit of TAVR in this high-risk group.

Outcomes of patients with early calcific aortic valve disease detected by clinically indicated echocardiography

AIMS

Previous studies have demonstrated relatively slow rates of progression of early calcific aortic valve disease (CAVD), which encompasses aortic sclerosis (ASc) and mild aortic stenosis (AS). The potential evolution to clinically significant AS is unclear, and we therefore examined the long-term outcomes of patients with ASc and mild AS detected at the time of clinically indicated echocardiography.

METHODS AND RESULTS

Data from initial clinically indicated echocardiograms performed between 2010 and 2018 in patients aged ≥18 years were extracted and linked to nationally collected outcome data. Those with impaired right or left systolic ventricular function or other significant left-sided valve disease were excluded. A time to first event analysis was performed with a composite primary outcome of cardiovascular death and aortic valve intervention (AVI). Of the 13 313 patients, 8973 had no CAVD, 3436 had ASc, and 455 had mild AS. The remainder had moderate or worse stenosis. Over a median follow-up period of 4.2 (interquartile range 1.8-6.7) years (and after adjustment for age and sex), those with ASc were at greater risk of the primary outcome [hazard ratio (HR) 2.9, 95% confidence interval (CI) 2.1-4.0] and need for AVI (HR 26.8, 95% CI 9.1-79.1) compared with those with no CAVD. Clinical event rates accelerated after ∼5 years in those with mild AS.

CONCLUSION

Patients with ASc are >25 times more likely to require AVI than those with no CAVD, and follow-up echocardiography should be considered within 3-4 years in those with mild AS.

Epicardial adipose tissue as an independent predictor of long-term outcome in patients with severe aortic stenosis undergoing transcatheter aortic valve replacement

BACKGROUND

Accurate risk stratification is important to improve patient selection and outcome of patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR). As epicardial adipose tissue (EAT) is discussed to be involved in cardiovascular disease, it could be useful as a marker of poor prognosis in patients with severe AS undergoing TAVR.

METHODS

A total of 416 patients diagnosed with severe AS by transthoracic echocardiography were assigned for TAVR and enrolled for systematic assessment. Patients underwent clinical surveys and 5-year long-term follow-up, with all-cause mortality as the primary endpoint. EAT volume was quantified on pre-TAVR planning CTs. Patients were retrospectively dichotomized at the median of 74 cm3 of EAT into groups with low EAT and high EAT volumes. Mortality rates were compared using Kaplan-Meyer plots and uni- and multivariable cox regression analyses.

RESULTS

A total number of 341 of 416 patients (median age 80.9 years, 45% female) were included in the final analysis. Patients with high EAT volumes had similar short-term outcome (p = 0.794) but significantly worse long-term prognosis (p = 0.023) compared to patients with low EAT volumes. Increased EAT volumes were associated with worse long-term outcome (HR1.59; p = 0.031) independently from concomitant cardiovascular risk factors, general type of AS, and functional echocardiography parameters of AS severity (HR1.69; p = 0.013).

CONCLUSION

Increased EAT volume is an independent predictor of all-cause mortality in patients with severe AS undergoing TAVR. It can be easily obtained from pre-TAVR planning CTs and may thus qualify as a novel marker to improve prognostication and management of patient with severe AS.

TRIAL REGISTRATION

DRKS, DRKS00024479.

Surgical aortic valve replacement etiologies, hemodynamics, and outcomes in 1346 patients from the Malaysian heart centre

BACKGROUND

This study examined the characteristics and outcomes of surgical aortic valve replacement (SAVR) both isolated and in combination with other cardiac surgery in Malaysia from 2015 to 2021.

METHODS

This was a retrospective study of 1346 patients analyzed on the basis of medical records, echocardiograms and surgical reports. The overall sample was both considered as a whole and divided into aortic stenosis (AS)/aortic regurgitation (AR)-predominant and similar-severity subgroups.

RESULTS

The most common diagnosis was severe AS (34.6%), with the 3 most common etiologies being bicuspid valve degeneration (45.3%), trileaflet valve degeneration (36.3%) and rheumatic valve disease (12.2%). The second most common diagnosis was severe AR (25.5%), with the most common etiologies being root dilatation (21.0%), infective endocarditis (IE) (16.6%) and fused prolapse (12.2%). Rheumatic valve disease was the most common mixed disease. A total of 54.5% had AS-predominant pathology (3 most common etiologies: bicuspid valve degeneration valve, degenerative trileaflet valve and rheumatic valve disease), 36.9% had AR-predominant pathology (top etiologies: root dilatation, rheumatic valve disease and IE), and 8.6% had similar severity of AS and AR. Overall, 62.9% of patients had trileaflet valve morphology, 33.3% bicuspid, 0.6% unicuspid and 0.3% quadricuspid. For AS, the majority were high-gradient severe AS (49.9%), followed by normal-flow low-gradient (LG) severe AS (10.0%), paradoxical low-flow (LF)-LG severe AS (6.4%) and classical LF-LG severe AS (6.1%). The overall in-hospital and total 1-year mortality rates were 6.4% and 14.8%, respectively. Pure severe AS had the highest mortality. For AS-predominant pathology, the etiology with the highest mortality was trileaflet valve degeneration; for AR-predominant pathology, it was dissection. The overall survival probability at 5 years was 79.5% in all patients, 75.7% in the AS-predominant subgroup, 83.3% in the AR-predominant subgroup, and 87.3% in the similar-severity subgroup.

CONCLUSIONS

The 3 most common causes of AS- predominant patients undergoing SAVR is bicuspid valve degeneration, degenerative trileaflet valve and rheumatic and for AR-predominant is root dilatation, rheumatic and IE. Rheumatic valve disease is an important etiology in our SAVR patients especially in mixed aortic valve disease. Study registration IJNREC/562/2022.

Treatment of severe symptomatic aortic valve stenosis using non-invasive ultrasound therapy: a cohort study

BACKGROUND

Calcific aortic stenosis is commonly treated using surgical or transcatheter aortic valve replacement; however, many patients are not considered suitable candidates for these interventions due to severe comorbidities and limited life expectancy. As such, non-invasive therapies might offer alternative therapeutic possibilities in these patients. This study aimed to assess the safety of non-invasive ultrasound therapy and its ability to improve valvular function by softening calcified valve tissue.

METHODS

This prospective, multicentre, single-arm series enrolled 40 adult patients with severe symptomatic aortic valve stenosis at three hospitals in France, the Netherlands, and Serbia between March 13, 2019, and May 8, 2022. Patients were treated with transthoracically delivered non-invasive ultrasound therapy. Follow-ups were scheduled at 1, 3, 6, 12, and 24 months. The primary endpoints were procedure-related deaths within 30 days and improved valve function. We report the 6-month data. This study is registered at ClinicalTrials.gov, NCT03779620 and NCT04665596.

FINDINGS

40 high-risk patients with a mean Society of Thoracic Surgeons score of 5·6% (SD 4·4) and multiple severe comorbidities were included. The primary endpoint, procedure-related mortality, did not occur; furthermore, no life-threatening or cerebrovascular events were reported. Improved valve function was confirmed up to 6 months, reflected by a 10% increase in mean aortic valve area from 0·58 cm2 (SD 0·19) at baseline to 0·64 cm2 (0·21) at follow-up (p=0·0088), and a 7% decrease in mean pressure gradient from 41·9 mm Hg (20·1) to 38·8 mm Hg (17·8; p=0·024). At 6 months, the New York Heart Association score had improved or stabilised in 24 (96%) of 25 patients, and the mean Kansas City Cardiomyopathy Questionnaire score had improved by 33%, from 48·5 (SD 22·6) to 64·5 (21·0). One serious procedure-related adverse event occurred in a patient who presented with a transient decrease in peripheral oxygen saturation. Non-serious adverse events included pain, discomfort during treatment, and transient arrhythmias.

INTERPRETATION

This novel, non-invasive ultrasound therapy for calcified aortic stenosis proved to be safe and feasible.

FUNDING

Cardiawave.

Physician assessment of aortic stenosis severity, quantitative parameters, and long-term outcomes: Results from the KP-VALVE project

BACKGROUND

Contemporary outcomes for aortic stenosis (AS) and the association between physician-assessed AS severity and quantitative parameters is poorly understood. We aimed to evaluate AS natural history, compare outcomes for physicians' AS assessment vs. quantitative parameters, and identify AS parameters with the most explanatory power.

METHODS

We ascertained physician-assessed AS severity, echocardiographic parameters, and clinical data for 546,769 patients from 2008-2018, examined multivariable associations of physician-assessed AS severity and number of quantitative severe AS parameters with death, cardiovascular hospitalization, and aortic valve replacement, and estimated the relative contribution of different quantitative AS parameters on outcomes.

RESULTS

Among 49,604 AS patients (mean [SD] age 77 [11] years), 17.6% had moderate, 3.6% moderate-severe, and 9.4% severe AS. During median 3.7 [IQR 1.7-6.8] years, physician-assessed AS severity strongly correlated with outcomes, with moderate AS patients tracking closest to mild AS, and moderate-to-severe AS patients more comparable to severe AS. Although the number of quantitative severe AS parameters strongly predicted outcomes (adjusted HR [95% CI] for death 1.40 [1.34-1.46], 1.70 [1.56-1.85], and 1.78 [1.63-1.94] for 1, 2, and 3 parameters, respectively), aortic valve area <1.0 cm2 was the most frequent severe AS parameter, explained the largest relative contribution (67%), and was common in patients classified as moderate (21%) or moderate-severe (56%) AS.

CONCLUSIONS

Physician-assessed AS severity predicts outcomes, with cumulative effects for each severe AS parameter. Moderate AS includes a wide spectrum of patients, with discordant AVA <1.0 cm2 being both common and predictive. Better identification of non-classical severe AS phenotypes may improve outcomes.

The prognostic significance of stroke volume index in low gradient severe aortic stenosis: from the national echo database of Australia

Approximately 50% of patients with severe aortic stenosis (AS) in clinical practice present with 'low-gradient' haemodynamics. Stroke Volume Index (SVI) is a measure of left ventricular output, with 'normal-flow' considered as  > 35 ml/m2. The association between SVI and prognosis in severe low-gradient AS (LGAS) in currently not well-understood. We analysed the National Echo Database of Australia (NEDA) and identified 109,990 patients with sufficiently comprehensive echocardiographic data, linked to survival information. We identified 1,699 with severe LGAS and preserved ejection fraction (EF) (≥ 50%) and 774 with severe LGAS and reduced EF. One- and three-year survival in each subgroup were assessed (follow-up of 74 ± 43 months), according to SVI thresholds. In patients with preserved EF the mortality "threshold" was at SVI < 30 ml/m2; 1- and 3-year survival was worse for those with SVI < 30 ml/m2 relative to those with SVI > 35 ml/m2 (HR 1.80, 95% CI 1.32-2.47 and HR 1.38, 95% CI 1.12-1.70), while survival was similar between those with SVI 30-35 ml/m2 and SVI > 35 ml/m2. In patients with reduced EF the mortality "threshold" was 35 ml/m2; 1- and 3-year survival was worse for both those with SVI < 30 ml/m2 and 30-35 ml/m2 relative to those with SVI > 35 ml/m2 (HR 1.98, 95% CI 1.27-3.09 and HR 1.41, 95% CI 1.05-1.93 for SVI < 30 ml/m2 and HR 2.02, 95% CI 1.23-3.31 and HR 1.56, 95% CI 1.10-2.21 for SVI 30-35 ml/m2). The SVI prognostic threshold for medium-term mortality in severe LGAS patients is different for those with preserved LVEF (< 30 ml/m2) compared to those with reduced LVEF (< 35 ml/m2).

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.

Low-flow, Low-gradient Severe Aortic Stenosis: A Review

Aortic stenosis (AS) is a common valve pathology experienced by patients worldwide. There are limited population-based studies assessing its prevalence; however, epidemiological studies emphasize that the burden of disease is growing. Recognizing AS relies on accurate clinical assessment and diagnostic investigations. Patients who develop severe AS are often referred to the heart team for assessment of aortic valve intervention. Although echocardiography has traditionally been used to screen and monitor the progression of AS, there can be discordance between measurements in a low-flow state. Such patients may have truly severe AS and potentially derive long-term benefit from aortic valve intervention. Accurately identifying these patients with the use of ancillary testing has been the focus of research for several years. In this article, we discuss the contemporary approaches and challenges in identifying and managing patients with low-flow, low-gradient severe AS.

Metabolomic Profiling in Patients with Different Hemodynamic Subtypes of Severe Aortic Valve Stenosis

Severe aortic stenosis (AS) is a common pathological condition in an ageing population imposing significant morbidity and mortality. Based on distinct hemodynamic features, i.e., ejection fraction (EF), transvalvular gradient and stroke volume, four different AS subtypes can be distinguished: (i) normal EF and high gradient, (ii) reduced EF and high gradient, (iii) reduced EF and low gradient, and (iv) normal EF and low gradient. These subtypes differ with respect to pathophysiological mechanisms, cardiac remodeling, and prognosis. However, little is known about metabolic changes in these different hemodynamic conditions of AS. Thus, we carried out metabolomic analyses in serum samples of 40 AS patients (n = 10 per subtype) and 10 healthy blood donors (controls) using ultrahigh-performance liquid chromatography-tandem mass spectroscopy. A total of 1293 biochemicals could be identified. Principal component analysis revealed different metabolic profiles in all of the subgroups of AS (All-AS) vs. controls. Out of the determined biochemicals, 48% (n = 620) were altered in All-AS vs. controls (p < 0.05). In this regard, levels of various acylcarnitines (e.g., myristoylcarnitine, fold-change 1.85, p < 0.05), ketone bodies (e.g., 3-hydroxybutyrate, fold-change 11.14, p < 0.05) as well as sugar metabolites (e.g., glucose, fold-change 1.22, p < 0.05) were predominantly increased, whereas amino acids (e.g., leucine, fold-change 0.8, p < 0.05) were mainly reduced in All-AS. Interestingly, these changes appeared to be consistent amongst all AS subtypes. Distinct differences between AS subtypes were found for metabolites belonging to hemoglobin metabolism, diacylglycerols, and dihydrosphingomyelins. These findings indicate that relevant changes in substrate utilization appear to be consistent for different hemodynamic subtypes of AS and may therefore reflect common mechanisms during AS-induced heart failure. Additionally, distinct metabolites could be identified to significantly differ between certain AS subtypes. Future studies need to define their pathophysiological implications.

Potential role of conventional and speckle-tracking echocardiography in the screening of structural and functional cardiac abnormalities in elderly individuals: Baseline echocardiographic findings from the LOOP study

Background

Elderly individuals occupy an increasing part of the general population. Conventional and speckle-tracking transthoracic echocardiography may help guide risk stratification in these individuals. The purpose of this study was to evaluate the potential utility of conventional and speckle-tracking echocardiography in the screening of cardiac abnormalities in the elderly population.

Methods

Two cohorts of elderly individuals (sample size: 1441 and 944) were analyzed, who were part of a randomized controlled clinical trial (LOOP study) and of an observational study (Copenhagen City Heart Study), recruiting participants from the general population >70 years of age with cardiovascular risk factors (arterial hypertension, diabetes mellitus, heart failure, or prior stroke) and sinus rhythm. Participants underwent a comprehensive transthoracic echocardiographic examination, including myocardial speckle tracking. Cardiac abnormalities were defined according to the ASE/EACVI guidelines.

Results

Structural cardiac abnormalities such as left ventricular (LV) remodeling, mitral annular calcification (MAC), and aortic valve sclerosis (with or without stenosis) were highly prevalent in the LOOP study (40%, 39%, and 27%, respectively). Moreover, a high prevalence of functional cardiac alterations such as LV diastolic dysfunction (LVDD), abnormal LV longitudinal systolic strain (GLS), and abnormal left atrial (LA) reservoir strain was present in the LOOP study (27%, 18%, and 9%, respectively). Likewise, the rate of LVDD, abnormal GLS, and abnormal LA reservoir strain was comparable in the validation sample from the Copenhagen City Heart Study. In line with these findings, subjects with LV remodeling, MAC, and aortic valve changes had a higher prevalence of LVDD, abnormal GLS, and abnormal LA reservoir strain than those without structural cardiac alterations.

Conclusion

The findings of this study highlight the potential clinical utility of conventional and speckle-tracking echocardiography in the screening of structural and functional cardiac abnormalities in the elderly population. Further studies are warranted to determine the prognostic relevance of these findings.

The role of TAVR in patients with heart failure: do we have the responses to all questions?

Severe aortic stenosis (AS) is the most prevalent valvular heart disease in developed countries. Heart failure (HF) is a frequent comorbidity of this condition and represents a diagnostic and therapeutic challenge. The spectrum of both conditions has become progressively wider in the last decade; HF has been divided in three groups according to left ventricular ejection fraction (LVEF) and severe AS has been reclassified into four groups according to aortic valve (AV) gradient, AV flow measured by LV stroke index, and LVEF. Although all four AS types may be found in patients with signs and symptoms of HF, low-flow AS with low or normal gradient is the most common type in these patients. Several studies have documented that patients with low-flow severe AS have a higher mortality risk than patients with normal-flow and high-gradient AS not only during the natural progression of the disease, but also after either interventional or surgical AV replacement. Existing data support transcatheter AV replacement (TAVR) in patients with severe AS, irrespective of AV gradient, AV flow, and LVEF. Controversial issues, however, are still present on this topic, which has not been adequately addressed by large studies and trials. This clinical review summarizes the epidemiology of the different HF types in patients with severe AS, as well as the impact of HF and LVEF on clinical outcomes of AS patients either untreated or after AV replacement. In particular, we addressed the influence of AV gradient and AV flow on all-cause and cardiovascular mortality in AS patients after TAVR.