Dahl, Jordi S.

Abstract Aims This study aims to describe the prevalence of discordant mild/moderate aortic stenosis (AS) in a population-based study and to identify the mechanisms that lead to reduced stroke volume (SV) and discordant moderate AS. Methods and results Discordant high-gradient (HG)-mild AS, defined as AVA > 1.5 cm2 and mean pressure gradient (MG) of 20–40 mmHg, and discordant low-gradient (LG) moderate AS, defined as AVA 1.0–1.5 cm2 and MG < 20 mmHg, were assessed in 883 individuals from the DANCAVAS screening study with aortic valve calcification and 257 individuals form the PROGRESSA study excluding those with left ventricular (LV) ejection fraction < 50%. In the DANCAVAS cohort, 150 men had mild/moderate AS of which 34% had discordance between MG and AVA, representing 66% with moderate AS. Among 262 patients in the combined cohort, 39% had discordant LG-moderate AS and 6% discordant HG-mild AS. Compared with concordant mild and moderate AS, individuals with discordant LG-moderate AS were more likely to present with LV concentric remodelling geometry (26 vs. 33 vs. 45%, P < 0.001), increased valvulo-arterial impedance (3.3 ± 0.7 vs. 3.6 ± 0.5 vs. 4.1 ± 0.7 mmHg/mL/m2, P < 0.001), and reduced systemic arterial compliance (SAC) (0.74 ± 0.22 vs. 0.81 ± 0.22 vs. 0.64 ± 0.18 mL/m2/mmHg, P < 0.001). Factors associated with SV index were relative wall thickness, LV end-diastolic diameter index, SAC, and LV remodelling pattern. Conclusion Discordant moderate AS is common, accounting for two-thirds of patients with moderate AS in the general male population. Patients with discordant LG-moderate AS have predominantly a concentric remodelling pattern with reduced SV. Reduced SV index was associated with signs of reduced vascular compliance, suggesting that altered vascular properties drive differences in remodelling patterns and discordant moderate AS.

Abstract Aims Aortic stenosis (AS) is a common and progressive disease, which, if left untreated, results in increased morbidity and mortality. Monitoring and follow-up care can be challenging due to significant variability in disease progression. This study aimed to develop machine learning models to predict the risks of disease progression and mortality in patients with mild AS. Methods and results A comprehensive database including 9611 patients with serial transthoracic echocardiograms was collected from a single institution across three clinical sites. The data set included parameters from echocardiograms, electrocardiograms, laboratory values, and diagnosis codes. Data from a single clinical site were preserved as an independent test group. Machine learning models were trained to identify progression to severe stenosis and all-cause mortality and tested in their performance for endpoints at 2 and 5 years. In the independent test group, the AS progression model differentiated those with progression to severe AS within 2 and 5 years with an area under the curve (AUC) of 0.86 for both. The feature of greatest importance was aortic valve mean gradient, followed by other valve haemodynamic measurements including valve area and dimensionless index. The mortality model identified those with mortality within 2 and 5 years with an AUC of 0.84 and 0.87, respectively. Smaller reduced-input validation models had similarly robust findings. Conclusion Machine learning models can be used in patients with mild AS to identify those at high risk of disease progression and mortality. Implementation of such models may facilitate real-time, patient-specific follow-up recommendations.

Abstract Background Guidelines acknowledge that discordant low-gradient (LG) aortic stenosis (AS) may be severe, but verifying this can be challenging. Right heart catheterization during exercise is considered the gold standard evaluating ventricular hemodynamics. No invasive studies have compared the hemodynamic response of discordant LG and severe AS during exercise. Purpose To describe exercise hemodynamics in patients with asymptomatic discordant AS and left ventricular ejection fraction ≥50%, and to identify the variables associated with the steepness of the pulmonary capillary wedge pressure (PCWP)/cardiac output (CO) slope defined as (peak exercise PCWP-rest PCWP)/(peak exercise CO-rest CO). Methods Patients with aortic valve area (AVA) ≤1.5 cm² underwent right heart catheterization at rest and during maximal exercise measuring pulmonary artery pressures, PCWP, CO and PCWP/CO slope. Patients were stratified in three groups: 1) discordant LG AS (AVA ≤1.0 cm² and mean gradient <40 mmHg); 2) moderate AS (AVA >1.0 cm²) and 3) high-gradient severe AS (AVA ≤1.0 cm² and mean gradient ≥40 mmHg). Results Among 86 patients, 17 (20%) had discordant LG, 49 (57%) moderate, and 20 (23%) high-gradient severe AS. The PCWP/CO slope was significantly steeper in discordant LG: median 3.3 mmHg/L/min (interquartile range: 2.2 mmHg/L/min) and high-gradient severe AS: 2.7 mmHg/L/min (1.5 mmHg/L/min) compared to moderate AS: 1.9 mmHg/L/min (2.0 mmHg/L/min), p=0.004. In a linear regression model adjusted for age, sex and rest PCWP, systemic arterial compliance and AS severity were significantly associated with the PCWP/CO slope. Furthermore, patients with discordant LG AS had a leftward and upward shift in the PCWP/CO slope. Conclusions Discordant LG and high-gradient severe AS had similar hemodynamic response to exercise with steeper PCWP/CO slope than in moderate AS, suggesting that discordant LG AS is a severe form of AS. In addition, the left-upward shift in PCWP/CO slope for discordant LG compared to high-gradient severe AS indicates that, this group also has latent heart failure with preserved ejection fraction physiology.

Abstract Background Dobutamine stress echocardiography (DSE) is recommended to distinguish between true-severe and pseudo-severe aortic stenosis (AS) in patients with low flow low-gradients and left ventricular ejection fraction (LVEF) <50%. However, DSE has mostly been tested in the setting of LVEF<35%. Purpose The purpose of this study was to examine the diagnostic accuracy of DSE according to aortic valve calcification (AVC) score, in patents with low-flow, low-gradient AS across a wide range of LVEF. Methods Patients with aortic mean gradient <40 mmHg, aortic valve area (AVA) <1.0 cm2, and stroke volume index (SVi) ≤35 mL/m2 undergoing DSE were identified from three prospectively collected patient cohorts, and stratified according to LVEF; <35%, 35-50% and >50%. Severe AS was defined as AVC score ≥2000 AU among men, and ≥1200 AU for women. Recommendation for severe AS according to DSE, are an AVA <1.0 cm2 combined with an aortic mean gradient ≥40 mmHg or peak velocity ≥4 m/s. Receiver operating characteristic curves for DSE-derived AVA, mean gradient and Vmax were used to identify optimal cut-off points for each LVEF subgroup. Results Of the 221 patients included in the study, 78 (35%) presented with LVEF <35%, 67 (30%) with LVEF 35-50%, and 76 (34%) with LVEF >50%. Baseline characteristics are presented in the table. Based on AVC, severe AS was present in 102 (46%) of patients. Using recommended thresholds for severe AS for AVC and DSE, led to a sensitivity of 49%, a specificity of 84% and an accuracy of 67% for DSE for all patients with LVEF <50%, but with significant heterogeneity between groups figure. AVA performed rather uniformly across LVEF subgroups; (AUC =0.68 vs 0.62 vs 0.54, p=0.36) LVEF<35%, LVEF 35-50%, LVEF>50% respectively and displayed a rather uniform optimal cut-off (1.0 cm2 vs 0.9 cm2 vs 0.8 cm2). However, mean gradient and Vmax during DSE, both showed significantly diagnostic heterogeneity across LVEF groups (AUC= 0.90 vs 0.67 vs 0.65, p=<0.001 and AUC= 0.90 vs 0.66 vs 0.60, p=<0.001) with different optimal thresholds (30 mmHg & 3.8 m/s, 45 mmHg & 4.3 m/s and 37mmHg & 4 m/s, LVEF<35%, LVEF 35-50%, LVEF>50%, respectively). Conclusion Our study shows, that the association between DSE gradients and AS severity assessed by AVC demonstrates important heterogeneity depending on LVEF. While DSE had the highest accuracy in patients with LVEF<35% both patients with LVEF 35-50%, and patients with LVEF>50% showed significantly less concordance between DSE and AVC.

Background Haemodynamic exercise testing is important for evaluating patients with dyspnoea on exertion and preserved ejection fraction. Despite very different pathologies, patients with pressure (aortic stenosis (AS)) and volume (mitral regurgitation (MR)) overload and diastolic dysfunction after recent acute myocardial infarction (AMI) reach similar filling pressure levels with exercise. The pressure–flow relationships (the association between change in cardiac output (∆CO) and change in pulmonary arterial wedge pressure (∆PAWP) may provide insight into haemodynamic adaptation to exercise in these groups. Methods and results One hundred sixty-eight subjects aged >50 years with a left ventricular ejection fraction of ≥50% underwent invasive exercise testing. They were enrolled in four different studies: AS (40 patients), AMI (52 patients), MR (43 patients) and 33 healthy subjects. Haemodynamic data were measured at rest, at 25 W, 75 W and at peak exercise. In all groups, PAWP increased with exercise. The greatest increase was observed in patients with AMI (from 12.7±3.9 mm Hg to 33.1±8.2 mm Hg, p<0.0001) and patients with AS (from 11.8±3.9 mm Hg to 31.4±6.1 mm Hg, p<0.0001), and the smallest was observed in healthy subjects (from 8.3±2.4 mm Hg to 21.1±7.5 mm Hg, p<0.0001). In all groups, the relative pressure increase was greatest at the beginning of the exercise. CO increased most in healthy patients (from 5.3±1.1 to 16.0±3.0 L/min, p<0.0001) and least in patients with AS (from 5.3±1.2 L/min to 12.4±2.6 L/min, p<0.0001). The pressure–flow relationships (∆PAWP/∆CO) and differed among groups (p = 0.02). In all groups, the pressure–flow relationship was steepest in the initial phase of the exercise test. The AMI and AS groups (2.3±1.2 mm Hg/L/min and 3.0±1.3 mm Hg/L/min, AMI and AS, respectively) had the largest overall pressure–flow relationship; the healthy group had the smallest initially and at peak exercise (1.3±1.1 mm Hg/L/min) followed by MR group (1.9±1.4 mm Hg/L/min). Conclusion The pressure–flow relationship was steepest in the initial phase of the exercise test in all groups. The pressure–flow relationship differs between groups. Trial registration numbers NCT01974557 , NCT01046838 , NCT02961647 and NCT02395107 .

AbstractAimsNew diastolic dysfunction (DD) guidelines were introduced in 2016 to replace the 2009 guidelines, but have not yet been evaluated in aortic stenosis (AS). We aimed to compare the 2009 and 2016 DD guidelines in severe AS patients in terms of association with left ventricular (LV) and left atrial (LA) remodeling, with pulmonary capillary wedge pressure (PCWP) at rest and exercise, and with prognosis.Methods and resultsWe included 212 patients with severe AS (112 undergoing AVR, 100 asymptomatic). Echocardiography, magnetic resonance imaging, and brain natriuretic peptides (BNP) were performed/measured. Thirty‐nine asymptomatic patients had PCWP measured during rest and maximal exertion. Asymptomatic patients were followed for 3.1 years for the combined endpoint of death, AVR or admission with heart failure. The 2009 and 2016 DD guidelines agreed poorly with each other (Cohens’ κ = .15). 2009 guidelines showed many ambiguous DD findings. With the 2016 guidelines, 20% of patients had indeterminate DD. DD grade 2 according to 2016 guidelines showed stronger association with symptom status, BNP, global longitudinal strain (GLS) and peak exercise PCWP than 2009 guidelines. For indeterminate DD patients according to 2009 guidelines, GLS above the median was associated with event‐free survival (HR .11 (95% CI .02–.53)). For neither guideline was DD associated with the combined endpoint in asymptomatic patients.ConclusionThe 2016 guidelines show a stronger association with BNP, GLS, and exercise PCWP than the 2009 guidelines. The 2016 guidelines result in 20% of patients with indeterminate DD; however, these patients may possibly be stratified according to GLS.

Introduction: Presence of subclinical left ventricle (LV) dysfunction may influence outcomes after percutaneous mitral balloon valvotomy (PMBV), but cannot be detected by conventional echocardiography. Hypothesis: Preprocedure LV global longitudinal strain (GLS) by speckle tracking TTE detects subclinical LV dysfunction and predicts long-term outcome after successful PMVB. Methods: Consecutive patients undergoing PMBV between 2003-2011 who had comprehensive baseline TTE were included. Patients with suboptimal immediate results (repeat PMBV or mitral surgery within first 6 months) and those with suboptimal TTE strain were excluded. LV strain was analyzed with commercial software (Syngo VVI), and GLS averaged from 18 segments. The primary end point was all-cause mortality. Secondary end point was the composite of death and mitral valve reintervention. Results: Of 110 patients screened, 29 (26%) had unsuitable strain imaging, and 8 (7%) had poor immediate results, leaving 73 in the final cohort. Median follow-up was 3.7 years (interquartile range 1.3-7.2). There were 10 deaths (14%) and 25 late mitral valve interventions (34%). Univariate predictors of death were GLS, age, EF, stroke volume, pulmonary artery pressure, mitral valve area and coronary artery disease. In a multivariate Cox model, GLS was the strongest predictor of death after adjustment for age [HR=1.40 (1.09-1.84), P=0.008]. For the composite endpoint, GLS, mitral valve gradient, and invasively mean left atrial pressure were univariate predictors of death or reintervention. At multivariate analysis, GLS was the sole predictor of events [HR=1.17 (1.01-1.34), P=0.03]. Event-free survival is shown in figure. Intra and inter observer intra-class correlation for strain analysis was 0.87 (0.66-0.96) and 0.84 (0.53-0.95), respectively. Conclusions: GLS is a powerful predictor of long-term outcome after PMVB and appears to have an incremental prognostic value over traditional parameters.

Introduction: In asymptomatic patients with severe aortic stenosis (SAS), left ventricular (LV) ejection fraction (EF) <50% is generally considered to be the threshold for referral for aortic valve replacement (AVR). Hypothesis: We investigated the importance of LVEF on long-term outcome after AVR in symptomatic and asymptomatic SAS patients and studied whether LVEF < 50% is the optimal threshold for referral for AVR. Methods and Results: We retrospectively identified 2017 patients with SAS (aortic valve area (AVA)<1cm2, mean aortic valve gradient ≥40 mm Hg, or indexed AVA <0.6 cm2/m2) who underwent surgical AVR from January 1995 to June 2009 at our institution. Patients were divided into 4 groups depending on preoperative LVEF (<50% in 300 (15%) patients, 50-59% in 331 (17%), 60-69% in 908 (45%), and ≥70% in 478 (24%)). The primary end-point was all-cause mortality. During follow-up of 5.3±4.4 years, 1056 (52%) died. Five-year mortality rate increased with decreasing LVEF (41% (n=106), LVEF<50%); 35% (n=98), LVEF 50-59%; 26% (n=192), LVEF 60-69%; 22% (n=90), LVEF≥70%, p<0.0001). Compared to patients with LVEF≥60%, patients with LVEF 50-59% had increased mortality (HR 1.58, p<0.001), with a similar risk increase in both symptomatic (HR=1.56, p<0.001) and asymptomatic patients (HR 1.58, p=0.006, Figure). In a Cox regression analysis corrected for standard risk factors, LV mass index, AVA, and stroke volume index, LVEF was predictive of all-cause mortality (HR=0.89 per 10%, p<0.001). When this multivariable analysis was repeated in the subset of 1333 patients with no history of coronary artery disease, LVEF was still associated with all-cause mortality (HR=0.90 per 10%, p=0.009). Conclusion: In patients with SAS undergoing AVR, patients with LVEF 50-59% have also increased mortality compared to patients with LVEF>60%, suggesting that a different LVEF threshold should be used when referring for AVR.

Background First-phase ejection fraction (EF1), the left ventricular (LV) ejection fraction (EF) until the time of peak transaortic velocity, is a novel marker of subclinical LV dysfunction able to predict adverse events in aortic stenosis (AS). This study investigated the association between end-systolic wall stress (ESWS) and EF1 in severe AS, as well as the prognostic value of EF1 in severe asymptomatic AS. Methods Two prospectively gathered cohorts of 94 asymptomatic patients and 108 symptomatic patients scheduled for aortic valve replacement (AVR), all with severe AS (aortic valve area <1 cm2) were stratified according to the median value of EF1 (33%). EF1 was defined as the EF at peak transaortic velocity. Asymptomatic patients were followed up for 3 years for the combined end-point of death, AVR or admission with heart failure. Results EF1 correlated with EF and was inversely associated with ESWS. In multivariate regression analysis, ESWS (p<0.001) and replacement fibrosis measured by MRI (p=0.02) were associated with EF1. Among asymptomatic patients, EF1 above the median was associated with the combined primary endpoint (HR=0.53 (95% CI 0.33 to 0.87)), while global longitudinal strain and EF were not. Among 42 patients with discordant AS (mean gradient <40 mm Hg), EF1 above median was associated with the primary endpoint (HR 0.28 (95% CI 0.12 to 0.61)). Conclusion EF1 is an afterload-dependent measure that is associated with events in patients with asymptomatic severe AS. The afterload dependency of EF1 may be useful in timing of risk stratification in patients with discordant AS. Trial registration numbers NCT02395107 and NCT02316587.

Objective To determine whether echocardiography-derived left ventricular filling pressure influences survival in patients with severe aortic stenosis (AS) undergoing aortic valve replacement (AVR). Methods We retrospectively reviewed 1383 consecutive patients with severe AS, normal ejection fraction and interpretable filling pressure undergoing AVR. Left ventricular filling pressure was determined according to current guidelines using mitral inflow, mitral annular tissue Doppler, estimated right ventricular systolic pressure and left atrial volume index. Cox proportional hazards regression was used to assess the influence of various parameters on mortality. Results Age was 75±10 years and 552 (40%) were female. Left ventricular filling pressure was normal in 325 (23%), indeterminate in 463 (33%) and increased in 595 (43%). Mean follow-up was 7.3±3.7 years, and mortality was 1.2%, 4.2% and 18.9% at 30 days and 1 and 5 years, respectively. Compared with patients with normal filling pressure, patients with increased filling pressure were older (78±9 vs 70±12, p<0.001), more often female (45% vs 35%, p=0.002) and were more likely to have New York Heart Association class III–IV symptoms (35% vs 24%, p=0.004), coronary artery disease (55% vs 42%, p<0.001) and concentric left ventricular hypertrophy (63% vs 37%, p<0.001). After correction for other factors, increased left ventricular filling pressure remained an independent predictor of mortality after successful AVR (adjusted HR 1.45 (95% CI 1.16 to 1.81), p=0.005). Conclusions Preoperative increased left ventricular filling pressure is common in patients with AS undergoing AVR and has important prognostic implications, regardless of symptom status. Future prospective studies should consider whether patients with increased filling pressure would benefit from earlier operation.