Remodeling in Aortic Stenosis With Reduced and Preserved Ejection Fraction: Insight on Motion Abnormality Via 3D + Time Personalized LV Modeling in Cardiac MRI

BACKGROUND

Increased afterload in aortic stenosis (AS) induces left ventricle (LV) remodeling to preserve a normal ejection fraction. This compensatory response can become maladaptive and manifest with motion abnormality. It is a clinical challenge to identify contractile and relaxation dysfunction during early subclinical stage to prevent irreversible deterioration.

PURPOSE

To evaluate the changes of regional wall dynamics in 3D + time domain as remodeling progresses in AS.

STUDY TYPE

Retrospective.

POPULATION

A total of 31 AS patients with reduced and preserved ejection fraction (14 AS_rEF: 7 male, 66.5 [7.8] years old; 17 AS_pEF: 12 male, 67.0 [6.0] years old) and 15 healthy (6 male, 61.0 [7.0] years old).

FIELD STRENGTH/SEQUENCE

1.5 T Magnetic resonance imaging/steady state free precession and late-gadolinium enhancement sequences.

ASSESSMENT

Individual LV models were reconstructed in 3D + time domain and motion metrics including wall thickening (TI), dyssynchrony index (DI), contraction rate (CR), and relaxation rate (RR) were automatically extracted and associated with the presence of scarring and remodeling.

STATISTICAL TESTS

Shapiro-Wilk: data normality; Kruskal-Wallis: significant difference (P < 0.05); ICC and CV: variability; Mann-Whitney: effect size.

RESULTS

AS_rEF group shows distinct deterioration of cardiac motions compared to AS_pEF and healthy groups (TIAS_rEF : 0.92 [0.85] mm, TIAS_pEF : 5.13 [1.99] mm, TIhealthy : 3.61 [1.09] mm, ES: 0.48-0.83; DIAS_rEF : 17.11 [7.89]%, DIAS_pEF : 6.39 [4.04]%, DIhealthy : 5.71 [1.87]%, ES: 0.32-0.85; CRAS_rEF : 8.69 [6.11] mm/second, CRAS_pEF : 16.48 [6.70] mm/second, CRhealthy : 10.82 [4.57] mm/second, ES: 0.29-0.60; RRAS_rEF : 8.45 [4.84] mm/second; RRAS_pEF : 13.49 [8.56] mm/second, RRhealthy : 9.31 [2.48] mm/second, ES: 0.14-0.43). The difference in the motion metrics between healthy and AS_pEF groups were insignificant (P-value = 0.16-0.72). AS_rEF group was dominated by eccentric hypertrophy (47.1%) with concomitant scarring. Conversely, AS_pEF group was dominated by concentric remodeling and hypertrophy (71.4%), which could demonstrate hyperkinesia with slight wall dyssynchrony than healthy. Dysfunction of LV mechanics corresponded to the presence of myocardial scarring (54.9% in AS), which reverted the compensatory mechanisms initiated and performed by LV remodeling.

DATA CONCLUSION

The proposed 3D + time modeling technique may distinguish regional motion abnormalities between AS_pEF, AS_rEF, and healthy cohorts, aiding clinical diagnosis and monitoring of AS progression. Subclinical myocardial dysfunction is evident in early AS despite of normal EF.

LEVEL OF EVIDENCE

4 TECHNICAL EFFICACY: Stage 1.

Prognostic Value of Left Ventricular Global Longitudinal Strain for Major Adverse Cardiovascular Events in Patients with Aortic Valve Disease: A Meta-Analysis

INTRODUCTION

Valvular heart disease is one of the most common heart diseases. It is characterized by abnormal function or structure of the heart valves. There may be no clinical symptoms in the early stages. Clinical symptoms of arrhythmia, heart failure, or thromboembolic events may occur in the late stages of the disease, such as palpitation after activities, breathing difficulties, fatigue, and so on. Aortic valve disease is a major part of valvular heart disease. The main treatment for aortic valve disease is valve replacement or repair surgery, but it is extremely risky. Therefore, a rigorous prognostic assessment is extremely important for patients with aortic valve disease. The global longitudinal strain is an index that describes the deformation capacity of myocardium. There is evidence that it provides a test for systolic dysfunction other than LVEF (left ventricular ejection fraction) and provides additional prognostic information.

METHOD

Search literature published between 2010 and 2023 on relevant platforms and contain the following keywords: "Aortic valve disease," "Aortic stenosis," "Aortic regurgitation," and "longitudinal strain" or "strain." The data is then extracted and collated for analysis.

RESULTS

A total of 15 articles were included. The total population involved in this study was 3,678 individuals. The absolute value of LVGLS was higher in the no-MACE group than in the MACE group in patients with aortic stenosis (Z = 8.10, p < 0.00001), and impaired LVGLS was a risk factor for MACE in patients with aortic stenosis (HR = 1.14, p < 0.00001, 95% CI: 1.08-1.20). There was also a correlation between impaired LVGLS and aortic valve surgery in patients with aortic valve disease (HR = 1.16, p < 0.0001, 95% CI: 1.08-1.25) or patients with aortic valve regurgitation (HR = 1.21, p = 0.0004, 95% CI: 1.09-1.34). We also found that impaired LVGLS had no significant association between LVGLS and mortality during the period of follow-up in patients with aortic valve stenosis (HR = 1.08, 95% CI: 0.94-1.25, p = 0.28), but it was associated with mortality in studies of prospective analyses (HR = 1.34, 95% CI: 1.02-1.75, p = 0.04).

CONCLUSIONS

Impaired LVGLS correlates with major adverse cardiovascular events in patients with aortic valve disease, and it has predictive value for the prognosis of patients with aortic valve disease.

Association of acute improvement in left ventricular longitudinal function after transcatheter aortic valve implantation with outcomes for severe aortic stenosis and preserved ejection fraction

BACKGROUND

Global longitudinal strain (GLS) is reportedly a sensitive marker for early subtle abnormalities in left ventricular (LV) performance of asymptomatic patients with severe aortic stenosis (AS) and preserved LV ejection fraction (LVEF). For symptomatic patients with severe AS and preserved LVEF, however, the association of immediate improvement in GLS after transcatheter aortic valve implantation (TAVI) with long-term outcomes remains uncertain.

METHODS

This study concerned 151 symptomatic patients with severe AS and preserved LVEF who had undergone TAVI. Echocardiography was performed before TAVI and 7 (7-9) days after TAVI. GLS was determined by means of a two-dimensional speckle-tracking strain using current guidelines. The primary endpoint was defined as a composite endpoint comprising cardiovascular death or re-hospitalization for HF after TAVI over a median follow-up period of 27.7 (11.9-51.4) months.

RESULTS

Mean LVEF and GLS were 65 ± 7 % and 12.8 ± 3.4 %, respectively. The Kaplan-Meier curve indicated that patients with acute improvement in GLS after TAVI experienced fewer cardiovascular events than those without such improvement (log-rank P = 0.02). Multivariate analysis showed that non-acute improvement in GLS after TAVI was independently associated with worse outcomes as well as deterioration of the mean transaortic pressure gradient.

CONCLUSION

Assessment of GLS immediately after TAVI is a valuable additional parameter for better management of symptomatic patients with severe AS and preserved LVEF who are scheduled for TAVI.

Shifting from Left Ventricular Ejection Fraction to Strain Imaging in Aortic Stenosis

Adverse ventricular remodeling is an inflexion point of disease progression in aortic stenosis (AS) and a major determinant of prognosis. Intervention before irreversible myocardial damage is of paramount importance to sustain favorable post-operative outcomes. Current guidelines recommend a left ventricular ejection fraction (LVEF)-based strategy to determine the threshold for intervention in AS. However, LVEF has several pitfalls: it denotes the left ventricular cavity volumetric changes and it is not suited to detecting subtle signs of myocardial damage. Strain has emerged as a contemporary imaging biomarker that describes intramyocardial contractile force, providing information on subclinical myocardial dysfunction due to fibrosis. A large body of evidence advocates its use to determine the switch from adaptive to maladaptive myocardial changes in AS, and to refine thresholds for intervention. Although mainly studied in echocardiography, studies exploring the role of strain in multi-detector row computed tomography and cardiac magnetic resonance are emerging. This review, therefore, summarizes contemporary evidence on the role of LVEF and strain imaging in AS prognosis, aiming to move from an LVEF-based to a strain-based approach for risk stratification and therapeutic decision-making in AS.

Characterization of myocardial mechanics and its prognostic significance in patients with severe aortic stenosis undergoing aortic valve replacement

AIMS

Aortic stenosis (AS) induces characteristic changes in left ventricular (LV) mechanics that can be reversed after aortic valve replacement (AVR). We aimed to comprehensively characterize LV mechanics before and after AVR in patients with severe AS and identify predictors of short-term functional recovery and long-term survival.

METHODS AND RESULTS

We prospectively performed comprehensive strain analysis by 2D speckle-tracking echocardiography in 88 patients with severe AS and LV ejection fraction ≥50% (mean age 71 ± 12 years, 42% female) prior to and within 7 days after AVR. Patients were followed for up to 5.2 years until death from any cause or last encounter. Within days after AVR, we observed an absolute increase in global longitudinal strain (GLS) (-16.0 ± 2.0% vs. -18.5 ± 2.1%, P<0.0001) and a decrease in apical rotation (10.5 ± 4.0° vs. 8.3 ± 2.8°, P = 0.0002) and peak systolic twist (18.2 ± 5.0° vs. 15.5 ± 3.8°, P = 0.0008). A baseline GLS is less negative than -16.2% was 90% sensitive and 67% specific in predicting a ≥ 20% relative increase in GLS. During a median follow-up of 3.8 years, a global circumferential systolic strain rate (GCSRs) less negative than -1.9% independently predicted lower survival.

CONCLUSION

In patients with severe AS, a reversal in GLS, apical rotation, and peak systolic twist abnormalities towards normal occurs within days of AVR. Baseline GLS is the strongest predictor of GLS recovery but neither was associated with long-term survival. In contrast, abnormal baseline GCSRs are associated with worse outcomes.

Impaired Left Ventricular Circumferential Midwall Systolic Performance Appears Linked to Depressed Preload, but Not Intrinsic Contractile Dysfunction or Excessive Afterload, in Paradoxical Low-Flow/Low-Gradient Severe Aortic Stenosis

Paradoxical low-flow/low-gradient aortic stenosis (P-LFLG-AS) occurs in about one-third of patients with severe AS and preserved left ventricular (LV) ejection fraction (EF). Our aim was to differentiate between altered LV loading conditions and contractility as determinants of subtle LV systolic dysfunction in P-LFLG-AS. We retrospectively analyzed medical records of patients with isolated severe degenerative AS and preserved EF (30 subjects with P-LFLG-AS and 30 patients with normal-flow/high-gradient severe AS (NFHG-AS)), without relevant coexistent diseases (e.g., diabetes, coronary artery disease and chronic kidney disease) or any abnormalities which could account for a low-flow state. Patients with P-LFLG-AS and NFHG-AS did not differ in aortic valve area index and most clinical characteristics. Compared to NFHG-AS, subjects with P-LFLG-AS exhibited smaller LV end-diastolic diameter (LVd) (44 ± 5 vs. 54 ± 5 mm, p < 0.001) (consistent with lower LV preload) with pronounced concentric remodeling, higher valvulo-arterial impedance (3.8 ± 1.1 vs. 2.2 ± 0.5 mmHg per mL/m2, p < 0.001) and diminished systemic arterial compliance (0.45 ± 0.11 vs. 0.76 ± 0.23 mL/m2 per mmHg, p < 0.001), while circumferential end-systolic LV midwall stress (cESS), an estimate of afterload at the LV level, was similar in P-LFLG-AS and NFHG-AS (175 ± 83 vs. 198 ± 69 hPa, p = 0.3). LV midwall fractional shortening (mwFS) was depressed in P-LFLG-AS vs. NFHG-AS (12.3 ± 3.5 vs. 14.7 ± 2.9%, p = 0.006) despite similar EF (61 ± 6 vs. 59 ± 8%, p = 0.4). By multiple regression, the presence of P-LFLG-AS remained a significant predictor of lower mwFS compared to NFHG-AS upon adjustment for cESS (β ± SEM: −2.35 ± 0.67, p < 0.001); however, the significance was lost after further correction for LVd (β = −1.10 ± 0.85, p = 0.21). In conclusion, the association of P-LFLG-AS with a lower cESS-adjusted mwFS, an index of afterload-corrected LV circumferential systolic function at the midwall level, appears secondary to a smaller LV end-diastolic cavity size according to the Frank−Starling law. Thus, low LV preload, not intrinsic contractile dysfunction or excessive afterload, may account for impaired LV circumferential midwall systolic performance in P-LFLG-AS.

Prognostic Value of Global Longitudinal Strain in Asymptomatic Aortic Stenosis: A Systematic Review and Meta-Analysis

Backgrounds

The presence of impaired global longitudinal strain (GLS) may be a valuable bio-marker in the early diagnosis for left ventricle (LV) impairment, which would help scrutinize asymptomatic aortic stenosis (AS) patients with high risk of adverse outcomes, such as major adverse cardiovascular events (MACE).

Methods

The study was prospectively registered in PROPSERO (CRD 42021223472). Databases, such as Pubmed, Embase, Cochrane Library, Web of science, and Scopus were searched for studies evaluating the impact of impaired GLS on MACE, all-cause mortality, and aortic valve replacement (AVR) in asymptomatic AS. Hazard ratios (HRs) with 95% CIs were calculated with meta-analysis for binary variants. Meta-regression, subgroup analysis, and sensitivity analyses were applied as needed to explore the heterogeneity.

Results

Eventually, a total of nine studies reporting 1,512 patients were enrolled. Compared with the normal GLS group, impaired GLS significantly increased MACE (HR = 1.20, 95% CI: 1.10–1.30, I² = 79%) with evident heterogeneity, all-cause mortality (HR = 1.42, 95% CI: 1.24–1.63), and AVR (HR = 1.17, 95% CI: 1.07–1.28). Subgroup analyses stratified by left ventricular ejection fraction (LVEF) > 50% or LVEF without precise cut-off point found that compared with the normal GLS group, impaired GLS remarkably increased MACE both in two subgroups (LVEF > 50%: HR: 1.22, 95% CI: 1.05–1.50; LVEF without cutpoint: HR: 1.25, 95% CI: 1.05–1.50). The results stratified by AS severity (mild/moderate and severe) or follow-up time resembled those stratified by LVEF. In addition, when subgroup analysis was stratified by mean aortic valve pressure gradient (MG ≥ 40 mm Hg and MG <40 mm Hg), compared with normal GLS, impaired GLS significantly increased MACE both in two subgroups (MG ≥ 40 mm Hg: HR: 3.41, 95% CI: 1.64–7.09; MG below 40 mm Hg: HR: 3.17, 95% CI: 1.87–5.38). Moreover, the effect sizes here were substantially higher than those in the former two stratified factors.

Conclusions

The presence of impaired GLS substantially worsens the outcomes for adverse cardiovascular events in asymptomatic patients with AS regardless of LVEF or AS severity or follow-up time or mean aortic valve pressure gradient, which highlights the importance of incorporating impaired GLS into risk algorithms in asymptomatic AS.

Systematic Review Registration

PROSPERO (registration number: CRD42021223472).

Proposal criteria of paradoxical low-flow low-gradient aortic stenosis for predicting prognosis in patients undergoing transcatheter aortic valve implantation

BACKGROUND

Paradoxical low-flow, low-gradient (PLF-LG) aortic stenosis (AS) is associated with poor prognosis in patients undergoing transcatheter aortic valve implantation (TAVI). This study aimed to verify the conventional criteria of PLF-LG AS (left ventricular ejection fraction [LVEF] > 50%, mean aortic valve pressure gradient [AVPG] < 40 mm Hg and stroke volume index [SVI] < 35 ml/m² by measuring Doppler method) compatible for predicting prognosis in patients undergoing TAVI.

MATERIALS AND METHODS

A total of 128 consecutive patients who underwent TAVI for AS with LVEF > 50% were enrolled. The primary endpoint was the hospital readmission due to heart failure (HRHF) and the secondary endpoint was all-cause mortality after hospital discharge. The patients were classified by both the conventional criteria of PLF-LG AS and the proposal criteria of PLF-LG AS if mean aortic valve pressure gradient (AVPG) < 40 mmHg and SVI by measuring Simpson's method < cut off value based on the ROC curve for predicting HRHF.

RESULTS

According to the conventional criteria, only 6 patients were diagnosed with PLF-LG AS. However, according to the proposal criteria, 16 patients were diagnosed with PLF-LG AS. Fourteen patients developed HRHF during the follow-up period after TAVI. Based on the ROC curves, SVI by measuring Simpson's method (cut off value = 25 ml/m²) had higher sensitivity and specificity for predicting HRHF (AUC = 0.74, p = 0.0013) than SVI by measuring Doppler method (AUC = 0.63, p = 0.045). The multivariate analysis revealed that PLF-LG AS defined by the proposal criteria (HR: 5.25; 95% CI: 1.60-17.16; p = 0.0073) but not by the conventional criteria was independently associated with HRHF. PLF-LG AS defined by the conventional criteria and the proposal criteria were not associated with all-cause mortality in the univariate analysis.

CONCLUSIONS

Our results demonstrated that new criteria of PLF-LG AS defined as SVI < 25 ml/m² measured by Simpson's method could predict HRHF in patients with severe AS who underwent TAVI.

Role of Exercise Testing and Speckle Tracking Echocardiography in Paradoxical Severe Aortic Stenosis

Introduction The clinical behavior and prognosis of patients with asymptomatic paradoxical low-gradient aortic stenosis (PLGAS) still remain controversial. Some authors consider PLGAS as an echocardiographically poorly quantified moderate AS (MAS). We aimed to investigate the clinical behavior of PLGAS by comparing it with that of asymptomatic high-gradient aortic stenosis (HG-AS) and MAS using transthoracic echocardiography (TTE) with speckle tracking imaging (STI) and cardiopulmonary exercise testing (CPET). The hypothesis of our study is, unlike that described by other authors, to demonstrate the existence of clinical and echocardiographic differences between PLGAS and MAS. Methods A cohort of 113 patients was included and categorized into three groups according to AS type: MAS (n=63), HG-AS (n=29), and PLGAS (n=21). Patients' clinical data were obtained. Patients underwent 2D TTE with STI and CPET. Results There were no significant differences in the clinical variables between the three AS groups. In the multivariate multinomial logistic regression analysis, with PLGAS being the reference category, the most powerful variable for establishing a difference with HG-AS was the left ventricular mass (LVM) indexed by body-surface area (odds ratio [OR]=1.04, confidence interval (CI)=1.01-1.06, p<0.05). The MAS group showed less abnormal CPET (OR=0.198, CI=0.06-0.69, p<0.05), and higher left ventricle global longitudinal strain rate (GLSR) (OR=0.003, CI=0.00-0.35, p<0.05) than the PLGAS group. Conclusions TTE with STI and CPET established the clear differences between patients with asymptomatic PLGAS and those with asymptomatic MAS, as well as the similarities between patients with PLGAS and those with HG-AS. Our data identify PLGAS as a completely different entity from MAS.

True-severe stenosis in paradoxical low-flow low-gradient aortic stenosis: outcomes after transcatheter aortic valve replacement

AIMS

The ESC/EACTS guidelines propose criteria that determine the likelihood of true-severe aortic stenosis (AS). We aimed to investigate the impact of the guideline-based criteria of the likelihood of true-severe AS in patients with low-flow low-gradient (LFLG) AS with preserved ejection fraction (pEF) on outcomes following transcatheter aortic valve replacement (TAVR).

METHODS AND RESULTS

In a prospective TAVR registry, LFLG-AS patients with pEF were retrospectively categorized into high (criteria ≥6) and intermediate (criteria <6) likelihood of true-severe AS. Haemodynamic, functional, and clinical outcomes were compared with high-gradient AS patients with pEF. Among 632 eligible patients, 202 fulfilled diagnostic criteria for LFLG-AS. Significant haemodynamic improvement after TAVR was observed in LFLG-AS patients, irrespective of the likelihood. Although >70% of LFLG-AS patients had functional improvement, impaired functional status [New York Heart Association (NYHA III/IV)] persisted more frequently at 1 year in LFLG-AS than in high-gradient AS patients (7.8%), irrespective of the likelihood (high: 17.4%, P = 0.006; intermediate: 21.1%, P < 0.001). All-cause death at 1 year occurred in 6.6% of high-gradient AS patients, 10.9% of LFLG-AS patients with high likelihood [hazard ratio (HR)adj 1.43, 95% confidence interval (CI) 0.68-3.02], and in 7.2% of those with intermediate likelihood (HRadj 0.92, 95% CI 0.39-2.18). Among the criteria, only the absence of aortic valve area ≤0.8 cm2 emerged as an independent predictor of treatment futility, a combined endpoint of all-cause death or NYHA III/IV at 1 year (OR 2.70, 95% CI 1.14-6.25).

CONCLUSION

Patients with LFLG-AS with pEF had comparable survival but worse functional status at 1 year than high-gradient AS with pEF, irrespective of the likelihood of true-severe AS.

CLINICAL TRIAL REGISTRATION

https://www.clinicaltrials.gov. NCT01368250.

Prognosis of paradoxical low-flow low-gradient aortic stenosis after transcatheter aortic valve replacement

AIMS

In paradoxical low-flow low-gradient severe aortic stenosis (PLFLG AS) patients, stroke volume index (SVI) is reduced despite preserved left ventricular ejection fraction (LVEF). Although reduced SVI is already known as a poor prognostic predictor, the outcomes of PLFLG AS patients after transcatheter aortic valve replacement (TAVR) have not been clearly defined. We retrospectively investigated the post-TAVR outcomes of PLFLG AS patients in comparison with normal-flow high-gradient aortic stenosis (NFHG AS) patients.

METHODS

The current observational study included 245 patients with NFHG AS (mean transaortic pressure gradient ≥40 mmHg and LVEF ≥ 50%) and 48 patients with PLFLG AS (mean transaortic pressure gradient <40 mmHg, LVEF ≥ 50% and SVI < 35 ml/m2). The endpoints were all-cause mortality, hospitalization for valve-related symptoms or worsening congestive heart failure and New York Heart Association functional class III or IV.

RESULTS

PLFLG AS patients had a significantly higher proportion with a history of atrial fibrillation/flutter as compared with NFHG AS patients. All-cause mortality of PLFLG AS patients was worse than that of NFHG AS patients (P = 0.047). Hospitalization for valve-related symptoms or worsening congestive heart failure was more frequent in PLFLG AS patients than in NFHG AS patients (P = 0.041). New York Heart Association functional class III-IV after TAVR was more frequently observed in PLFLG AS patients (P = 0.019).

CONCLUSION

The outcomes of PLFLG AS patients were worse than those of NFHG AS patients in this study. Preexisting atrial fibrillation/flutter was frequent in PLFLG AS patients, and may affect their post-TAVR outcomes. Therefore, closer post-TAVR follow-up should be considered for these patients.

Benefit of Transcatheter Aortic Valve Replacement in Patients With Paradoxical Low-Flow Low-Gradient Versus High-Gradient Aortic Stenosis and Preserved Left Ventricular Function

[Figure: see text].

Dissecting myocardial mechanics in patients with severe aortic stenosis: 2-dimensional vs 3-dimensional-speckle tracking echocardiography

Background

Aortic stenosis (AS) causes left ventricular (LV) pressure overload, leading to adverse LV remodeling and dysfunction. Identifying early subclinical markers of LV dysfunction in patients with significant AS is critical as this could provide support for earlier intervention, which may result in improved long-term outcomes. We therefore examined the impact of severe AS and its consequent increase in LV afterload on myocardial deformation and rotational mechanics by 2-dimensional (2D) and 3-dimensional (3D) speckle-tracking echocardiography.

Methods

We prospectively measured various strain parameters in 168 patients (42% female, mean age 72 ± 12 years) with severe AS and LV ejection fraction (EF) ≥50%, and compared them to normal values found in literature. 2D and 3D images were analyzed for global longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS), basal rotation, apical rotation, and peak systolic twist. We further assessed the degree of concordance between 2D and 3D strain, and examined their association with measures of LV preload and afterload.

Results

Patients with severe AS exhibited significantly lower GLS and GRS but higher GCS, apical rotation, and twist by 2D and 3D echocardiography compared with published normal values (P = 0.003 for 3D twist, P < 0.001 for all others). Agreement between 2D- and 3D-GLS by concordance correlation coefficient was 0.49 (95% confidence interval: 0.39–0.57). GLS was correlated with valvulo-arterial impedance, a measure of LV afterload (r = 0.34, p < 0.001 and r = 0.23, p = 0.003, respectively).

Conclusion

Patients with severe AS demonstrated lower-than-normal GLS and GRS but appear to compensate with higher-than-normal GCS, apical rotation, and twist in order to maintain a preserved LVEF. GLS showed a modest correlation with valvulo-arterial impedance.

Aortic pulse wave velocity and its relationship with transaortic flow and gradients in patients with severe aortic stenosis undergoing aortic valve replacement

Background

Low-flow, low-gradient severe aortic stenosis (LFLGAS) is a common clinical entity and is associated with poor prognosis. Increased left ventricular (LV) afterload is one of the mechanisms contributing to low LV stroke volume index (SVi) in these patients. Aortic stiffness is an important determinant of LV afterload, but no previous study has evaluated its relationship with LVSVi in patients with AS.

Methods

Fifty-seven patients (mean age 66 ± 8 years, 71.9% men) with severe AS [aortic valve area (AVA) < 1.0 cm²] undergoing aortic valve replacement (AVR) were included in this study. Echocardiographic parameters of AS were correlated with carotid-femoral pulse wave velocity (cfPWV), a measure of aortic stiffness, derived using PeriScope® device.

Results

Mean AVA was 0.63 ± 0.17 cm² with mean and peak transvalvular gradient 56.5 ± 18.8 mmHg and 83.2 ± 25.2 mmHg, respectively. Nearly half (26 of 57, 45.6%) of the subjects had SVi <35 mL/m², indicative of low-flow severe AS. These subjects had lower AVA, lower aortic valve gradient, and LV ejection fraction. CfPWV was numerically lower in these subjects [median 1467 (interquartile range 978, 2259) vs 1588 (1106, 2167)] but the difference was not statistically significant (p = 0.66). However, when analyzed as a continuous variable, cfPWV had significant positive correlation with SVi (Pearson's r 0.268, p = 0.048) and mean aortic valve gradient (Pearson's r 0.274, p = 0.043).

Conclusions

In patients with severe AS undergoing AVR, aortic stiffness measured using cfPWV is not a determinant of low-flow state. Instead, an increasing cfPWV tends to be associated with increasing transvalvular flow and gradient in these patients.

Contemporary Outcomes in Low-Gradient Aortic Stenosis Patients Who Underwent Dobutamine Stress Echocardiography

Background

Detection of flow reserve (FR) by dobutamine stress echocardiography is used for risk stratification in low‐gradient aortic stenosis (AS). Prognostic significance of dobutamine stress echocardiography in the transcatheter aortic valve replacement era is unclear. We aimed to assess the current relevance of FR.

Methods and Results

We studied 235 patients with low‐gradient severe AS (rest aortic valve area ≤1.0 cm² or indexed aortic valve area ≤0.60 cm²/m²; mean aortic valve gradient <40 mm Hg) and left ventricular ejection fraction <50%) with dobutamine stress echocardiography done September 2010 through July 2016. FR was defined by ≥20% stroke volume increase. We diagnosed “true‐severe AS” if peak aortic valve velocity ≥4 m/s occurred with aortic valve area ≤1.0 cm² (or indexed aortic valve area ≤0.6 cm²/m²). At a median time of 51 days, 128 patients underwent aortic valve replacement,either surgical aortic valve replacement (n=42) or transcatheter aortic valve replacement (n=86). FR was observed in 138 patients, while 86 patients had true‐severe AS. During median follow‐up of 2.3 years, 138 patients died. In a multivariable model, aortic valve replacement (hazard ratio 0.41, 95% CI: 0.29–0.58, P <0.001) and lower Society of Thoracic Surgeons score (hazard ratio 1.06, 95% CI: 1.04–1.09, P<0.001) were associated with better survival, while FR was not predictive. aortic valve replacement was associated with survival regardless of the presence or absence of FR or AS severity stratification.

Conclusions

In low‐gradient AS with reduced ejection fraction, FR or AS severity stratification by dobutamine stress echocardiography was not associated with survival. Aortic valve replacement was associated with better survival in low‐gradient AS independent of FR.

See Editorial by Annabi et al

Elderly Japanese Standard Data of Echocardiography; From J-LONG study

BACKGROUND

Age-related changes in cardiac morphology and function have not been unknown in the elderly. The Japanese eLderly data Of Normal echocardioGraphy (J-LONG) study is a prospective multicenter cohort study and aimed to investigate the echocardiographic data in the healthy Japanese elderly.

METHODS

Thirty domestic facilities participated in this study, and 130 healthy subjects (57 men, 73 women, 79.6 ± 4.7 years, range 75-98 years, interquartile range 76-82 years) were enrolled in this cohort. Echocardiographic and clinical data sets were obtained in each facility, and total analyses were performed in the University of Tsukuba.

RESULTS

Almost all cardiac morphological data were significantly larger in men than those in women. However, corrected data by body surface area (BSA) were similar or closer between genders. As a gender difference, the negative correlation between BSA and age was observed in women only (r = - 0.46, p < 0.001), showing the independent determinant of women's left ventricular end-diastolic volume (LVEDV) was age (β = - 0.29, p = 0.01), but not BSA. In men, LVEDV was significantly correlated with BSA (β = 0.42, p = 0.001), but not with age (p = 0.10). Also, women had higher LV ejection fraction (70 ± 7.1 vs. 68 ± 4.9%, p = 0.02), lower E/A (0.67 ± 0.16 vs. 0.75 ± 0.21, p = 0.02), and higher E/e' (10 ± 2.7 vs. 8.9 ± 2.5, p = 0.03) as compared to men.

CONCLUSIONS

The J-LONG study suggested that correction by the physique was needed to interpret echocardiographic data of the elderly. Also, gender differences and age-related changes in cardiac morphology and function were observed, and further studies are needed to confirm the clinical significance.

Coronary Microcirculation in Aortic Stenosis

Aortic stenosis is a heterogeneous disorder. Variations in the pathological and physiological responses to pressure overload are incompletely understood and generate a range of flow and pressure gradient patterns, which ultimately cause varying microvascular effects. The impact of cardiac-coronary coupling depends on these pressure and flow effects. In this article, we explore important concepts concerning cardiac physiology and the coronary microcirculation in aortic stenosis and their impact on myocardial remodeling, aortic valve flow patterns, and clinical progression.

Reduced Left Ventricular Global Longitudinal Strain Predicts Prolonged Hospitalization: A Cohort Analysis of Patients Having Aortic Valve Replacement Surgery

BACKGROUND

Left ventricular ejection fraction (LVEF) is often preserved in patients with aortic stenosis and thus cannot distinguish between normal myocardial contractile function and subclinical dysfunction. Global longitudinal strain and strain rate (SR), which measure myocardial deformation, are robust indicators of myocardial function and can detect subtle myocardial dysfunction that is not apparent with conventional echocardiographic measures. Strain and SR may better predict postoperative outcomes than LVEF. The primary aim of our investigation was to assess the association between global longitudinal strain and serious postoperative outcomes in patients with aortic stenosis having aortic valve replacement. Secondarily, we also assessed the associations between global longitudinal SR and LVEF and the outcomes.

METHODS

In this post hoc analysis of data from a randomized clinical trial (NCT01187329), we examined the association between measures of myocardial function and the following outcomes: (1) need for postoperative inotropic/vasopressor support; (2) prolonged hospitalization (>7 days); and (3) postoperative atrial fibrillation. Standardized transesophageal echocardiographic examinations were performed after anesthetic induction. Myocardial deformation was measured using speckle-tracking echocardiography. Multivariable logistic regression was used to assess associations between measures of myocardial function and outcomes, adjusted for potential confounding factors. The predictive ability of global longitudinal strain, SR, and LVEF was assessed as area under receiver operating characteristics curves (AUCs).

RESULTS

Of 100 patients enrolled in the clinical trial, 86 patients with aortic stenosis had acceptable images for global longitudinal strain analysis. Primarily, worse intraoperative global longitudinal strain was associated with prolonged hospitalization (odds ratio [98.3% confidence interval], 1.22 [1.01-1.47] per 1% decrease [absolute value] in strain; P = .012), but not with other outcomes. Secondarily, worse global longitudinal SR was associated with prolonged hospitalization (odds ratio [99.7% confidence interval], 1.68 [1.01-2.79] per 0.1 second(-1) decrease [absolute value] in SR; P = .003), but not other outcomes. LVEF was not associated with any outcomes. Global longitudinal SR was the best predictor for prolonged hospitalization (AUC, 0.72), followed by global longitudinal strain (AUC, 0.67) and LVEF (AUC, 0.62).

CONCLUSIONS

Global longitudinal strain and SR are useful predictors of prolonged hospitalization in patients with aortic stenosis having an aortic valve replacement.

Two-dimensional Echocardiographic Assessment of Myocardial Strain: Important Echocardiographic Parameter Readily Useful in Clinical Field

Echocardiography is the first and is the most-available imaging modality for many cardiovascular diseases, and echocardiographic parameters can give much important information for diagnosis, treatment, and prognostic evaluations. Left ventricular ejection fraction (LVEF) is the most commonly used echocardiographic parameter for left ventricular (LV) systolic function. Although LVEF is used routinely in daily practice, it is calculated from volumetric change without representing true myocardial properties. Recently, strain echocardiography has been used to objectively measure myocardial deformation. Myocardial strain can give accurate information about intrinsic myocardial function, and it can be used to detect early-stage cardiovascular diseases, monitor myocardial changes with specific therapies, differentiate cardiomyopathies, and predict the prognosis of several cardiovascular diseases. Although strain echocardiography has been applied to measure the right ventricle and left atrium, in addition to analyzing the LV, many cardiologists who are not imaging specialists are unaware of its clinical use and importance. Therefore, this review describes the measurement and clinical utility of 2-dimensional strain analysis in various cardiovascular diseases.

Clinical application of echocardiographic-derived myocardial strain imaging in subclinical disease: a primer for cardiologists

PROPOSE OF REVIEW

To highlight the evidence to support the measurement of left ventricular (LV) global longitudinal strain (GLS) in the risk assessment and management of patients with valvular heart disease.

RECENT FINDINGS

Subclinical myocardial dysfunction that is characterized by impaired LV GLS is often present in patients with valvular disease. The addition of GLS to the LV systolic function assessment refines disease classification and improves both prognosis and management of valvular disease.

SUMMARY

The measurement of global systolic function is essential in risk assessment and management of all patients with valvular heart disease. Although LV ejection fraction remains the main parameter of systolic function, strain measurement has emerged as a promising systolic function marker. Strain describes deformation of the myocardium that occurs during the cardiac cycle in the longitudinal, circumferential, and radial planes. Of all the regional strain deformation measurements, evidence gathered over the last decade has shown that GLS improves detection of systolic dysfunction beyond LV ejection fraction and provides additional prognostic information.

Utility of strain imaging in conjunction with heart failure stage classification for heart failure patient management

The American College of Cardiology Foundation/American Heart Association (ACCF/AHA) classification, based on structural changes and symptoms, classifies stages of heart failure (HF) development as Stages A-D. This HF classification emphasizes the development and progression of the disease and can be used to describe individuals and populations. Since HF is considered a progressive disorder that can be represented as a clinical continuum, individuals at a particular HF stage require specific management with the long-term goal of avoiding HF development and progression. Although early detection of subclinical left ventricular (LV) dysfunction is essential for delaying progression to HF, the assessment of such dysfunction can be challenging. While echocardiography plays a pivotal role in the quantification and early detection of LV structural findings, two-dimensional speckle-tracking echocardiographic parameters, especially global longitudinal strain (GLS), have recently been reported to be sensitive markers of early subtle abnormalities of LV myocardial performance. They are thus helpful for prediction of outcomes for various cardiac diseases, and superior to conventional echocardiographic indices such as LV ejection fraction, mitral inflow E and mitral e' annular velocities ratio. Strain imaging, especially GLS-guided management for patients at a particular stage of HF, may therefore have the potential to prevent progression to later HF stages and may offer new insights into the management of HF patients. This article reviews the utility of strain imaging, especially GLS in conjunction with HF stage classification, and future perspectives for HF patient management.

Prognostic Impact of Low-Flow Severe Aortic Stenosis in Small-Body Patients Undergoing TAVR: The OCEAN-TAVI Registry

OBJECTIVES

This study aimed to analyze the prognostic impact of low-flow (LF) severe aortic stenosis in small-body patients undergoing transcatheter aortic valve replacement (TAVR).

BACKGROUND

Western literature demonstrates a poor prognosis with paradoxical LF and low-flow low-gradient (LF-LG) severe aortic stenosis (AS), as defined by stroke volume index (SVi) <35 ml/m² and mean pressure gradient <40 mm Hg with preserved left ventricular ejection fraction (LVEF). However, this poor prognosis is contested in Japan owing to the smaller body size of Japanese patients relative to that of Western patients. Additionally, there are no reports of the prognostic implication of paradoxical LF or LF-LG severe AS in small-body patients undergoing TAVR.

METHODS

This was a retrospective analysis of 723 consecutive Japanese patients (median age 85 years; 32.6% male; median body surface area 1.4 m²) who underwent TAVR for severe AS at 9 sites in Japan. The primary and secondary endpoints were cumulative all-cause and cardiovascular mortality after TAVR, respectively.

RESULTS

Ninety-seven (13.4%) patients had paradoxical LF severe AS whereas 38 (5.3%) had paradoxical LF-LG with severe AS. PLF was associated with a significant increase in all-cause (hazard ratio [HR]: 3.00; 95% confidence interval [CI]: 1.34 to 6.72; p < 0.001) and cardiovascular mortality (HR: 5.58; 95% CI: 1.19 to 26.2; p < 0.01), as compared with patients' normal flow and preserved LVEF. PLF-LG was associated with a significant increase in all-cause mortality (HR: 3.76; 95% CI: 1.09 to 13.73; p < 0.01), as compared with normal flow high gradient with preserved LVEF. SVi was an independent predictor of cardiovascular mortality on multivariate analysis after adjustments for age, sex, clinically relevant variables, and other echocardiographic parameters (HR: 1.96; 95% CI: 1.19 to 3.23; p < 0.01).

CONCLUSIONS

Among Japanese small-body patients with severe AS, both paradoxical LF and LF-LG severe AS were associated with poor outcomes following TAVR. SVi was an independent predictor of cardiovascular mortality after TAVR. (Optimised Transcatheter Valvular Intervention registry [OCEAN-TAVI]; UMIN000020423).

Left Ventricular Global Strain for Estimating Relaxation and Filling Pressure - A Multicenter Study

BACKGROUND

Speckle-tracking echocardiography (STE)-derived parameters may have better correlation with left ventricular (LV) relaxation and filling pressure than tissue Doppler-derived parameters. However, it has not been elucidated which parameter - strain or strain rate - and which direction of myocardial deformation - longitudinal or circumferential - is the most useful marker of LV relaxation and filling pressure.

METHODS AND RESULTS

We conducted a prospective multicenter study and compared the correlation of tissue Doppler- and STE-derived parameters with the time constant of LV pressure decay (τ) and LV mean diastolic pressure (MDP) in 77 patients. The correlation of early-diastolic mitral annular velocity (e´) with τ was weak (r=-0.32, P<0.01), and that of peak longitudinal strain (LS) was the strongest (r=-0.45, P<0.001) among the STE-derived parameters. There was a modest correlation between LVMDP and the ratio of early-diastolic inflow velocity (E) to e´ (E/e´) (r=0.50, P<0.001). In contrast, the ratio of E to LS (E/LS) correlated strongly with LVMDP (r=0.70, P<0.001). The correlation of E/LS with LVMDP was significantly better than that for E/e´ (P<0.01). Receiver-operating characteristic analysis showed that E/LS had the largest area under the curve for distinguishing elevated LVMDP (E/LS 0.86, E/e´ 0.74, E/A 0.67).

CONCLUSIONS

STE-derived longitudinal parameters correlated well with LV relaxation and filling pressure. In particular, E/LS could be more accurate than E/e´ for estimating LV filling pressure. (Circ J 2016; 80: 1163-1170).

Risk Factors for Progression of Degenerative Aortic Valve Disease in the Japanese- The Japanese Aortic Stenosis Study (JASS) Prospective Analysis

BACKGROUND

Because of ethnic difference in the risk of degenerative aortic valve disease (DAVD), risk factors should be clarified in each race to establish prophylactic strategies for severe aortic valve stenosis (AS).

METHODS AND RESULTS

This study prospectively followed 359 Japanese subjects with DAVD and age ≥50 years for 3 years. As both patients with peak aortic transvalvular flow velocity ≥2 m/s and <2 m/s were enrolled, subgroup analysis was also conducted. Most patients were under treatment for their comorbidities. The use of warfarin, but none of the traditional risk factors for atherosclerosis, was related to greater reduction in aortic valve area indexed to body surface area (iAVA). In patients with peak aortic transvalvular flow velocity <2 m/s, the use of an angiotensin-receptor blocker (ARB) was associated with less decrease in iAVA. In patients with peak velocity ≥2 m/s, changes in iAVA were not related to any baseline characteristics, but peak velocity was less increased under treatment with an angiotensin-converting enzyme inhibitor (ACEI).

CONCLUSIONS

In Japanese, the use of warfarin may exacerbate DAVD, and augmented management of atherosclerotic risk factors beyond the recommendations in the current guidelines is unlikely to exert additional benefit. The prescription of ARB for DAVD patients before the development of AS or ACEI after the development of AS may be useful.

Visual Assessment of Relative Apical Sparing Pattern Is More Useful Than Quantitative Assessment for Diagnosing Cardiac Amyloidosis in Borderline or Mildly Increased Left Ventricular Wall Thickness

BACKGROUND

Relative apical sparing pattern of longitudinal strain (RapSP-LS) was suggested in advanced cardiac amyloidosis (CA). It is unclear whether it is present in less advanced CA.

METHODS AND RESULTS

Patients with presumptive diagnosis of CA and mean left ventricular wall thickness (LVWT) ≤14 mm were recruited. Apart from RapSP-LS visually identified, relative apical longitudinal strain index (RapLSI) was defined as [average apical LS/(average basal LS+average mid-ventricle LS)]. Among 119 patients included, 47 were finally diagnosed with CA. RapLSI was higher in the CA group compared to other causes of increased mean LVWT (P<0.001), but with a significant range of overlap noted. In contrast, RapSP-LS visually assessed was noted in most CA patients (31/47, 66.0%) except in those with preserved LV ejection fraction, normal LVWT, and mildly decreased global LS, suggesting least advanced CA. On multivariate analysis of the added diagnostic role of RapSP-LS or RapLSI on top of clinical, electrocardiographic, and conventional echocardiographic parameters, addition of RapLSI produced only borderline increase in area under the curve of the multivariate model (P=0.05), whereas addition of RapSP-LS significantly increased it (P<0.001).

CONCLUSIONS

Visual identification of RapSP-LS is useful in terms of added diagnostic value compared with quantitative calculation of RapLSI. Its clinical application, however, should be used with caution in patients with less advanced CA.

Low gradient aortic stenosis

OPINION STATEMENT

Severe low-gradient (LG) aortic stenosis (AS) [aortic valve area (AVA) ≤ 1.0 cm(2), mean pressure gradient (MG) < 40 mmHg] represents a frequently encountered and challenging clinical dilemma. A systematic approach, which often requires several imaging modalities, should be undertaken to confirm the hemodynamic findings and rule out measurement error. Low-flow conditions often account for the discrepancy and can be present whether the left ventricular ejection fraction (LVEF) is depressed or normal. In patients with classical low-flow (LF), LG AS in which LVEF is reduced (<40-50 %), dobutamine stress echocardiography (DSE) should be used to distinguish patients with true severe AS and pseudo-severe AS, as well as to evaluate for the presence of left ventricular contractile or flow reserve. Surgical or transcatheter aortic valve replacement (AVR) should likely be reserved for those patients with true severe AS. Patient outcome with medical or surgical management generally relates to patient functional capacity, stenosis severity, and left ventricular functional reserve. Patients with severe LG AS with preserved LVEF can have a stroke volume that is either normal (>35 mL/m(2)) or low (<35 mL/m(2)). New data suggest that DSE can identify pseudo-severe AS in up to 30 % of patients with severe LF-LG AS with preserved LVEF. AVR should likely be restricted to those patients with true severe AS, although there is currently little data to support this strategy. Symptomatic patients with severe LG AS with preserved LVEF, whether they have normal or low flow, should be offered AVR. Transcatheter AVR provides an alternative therapeutic option in the high-risk patient.

Prognostic value of paradoxical low-gradient severe aortic stenosis in Japan: Japanese Multicenter Aortic Stenosis Study, Retrospective (JUST-R) Registry

BACKGROUND

Whether the prognosis of paradoxical low-gradient severe aortic stenosis (PLG-SAS), especially due to paradoxical low-flow low-gradient SAS (PLFLG-SAS), is malignant in any specific ethnicity, including Japanese, remains unclear.

METHODS

We retrospectively enrolled 385 consecutive Japanese patients (age, 76±8 years; 148 men) with moderate AS [MAS: 0.6≤indexed aortic valve area (iAVA)<0.85cm(2)/m(2)] or SAS (iAVA <0.6cm(2)/m(2)) with preserved left ventricular ejection fraction (≥50%). SAS patients were divided into PLG-SAS and high-gradient (HG)-SAS according to the transvalvular mean gradient (40mmHg). PLG-SAS was categorized into 2 groups: normal-flow (NF) LG-SAS [stroke volume index (SVi) ≥35mL/m(2)] and PLFLG-SAS (SVi <35mL/m(2)). Endpoints were all-cause death and major adverse cardio-cerebrovascular events (MACE).

RESULTS

During a median follow-up of 15 months, 31 patients died and 48 suffered MACE. All-cause death and MACE rates in PLG-SAS and PLFLG-SAS were significantly lower than those in HG-SAS and similar to those in MAS. On multivariate analysis, neither PLG-SAS nor PLFLG-SAS were independent determinants for all-cause death compared with MAS [MAS as reference, PLG-SAS: hazard ratio (HR) 0.47, p=0.32; PLFLG-SAS: HR 0.01, p=0.20; HG-SAS: HR 3.37, 95% confidence interval 1.24-9.74, p=0.02].

CONCLUSIONS

In Japanese patients, the prognoses of PLG-SAS and PLFLG-SAS were better than that of HG-SAS and similar to that of MAS, being better than that in Western populations.