Prognostic value of left ventricular and left atrial strain imaging in moderate to severe aortic stenosis: Insights from an Asian population

BACKGROUND

Data regarding the prognostic value of left atrial (LA) strain in aortic stenosis (AS) is scarce, especially in Asian population and moderate AS.

METHOD

Left ventricular global longitudinal strain (LVGLS), LA reservoir strain (LASr), conduit strain (LAScd), and contractile strain (LASct) were measured using automated speckle-tracking echocardiography in consecutive patients with moderate or severe AS. The primary endpoint was a composite of all-cause death (ACD) and major adverse cardiovascular events (MACE; myocardial infarction, syncope, and heart failure hospitalization).

RESULTS

Of 712 patients (mean age, 78 ± 12 years; 370 [52%] moderate AS; 342 [48%] severe AS), average LV ejection fraction (LVEF) was 68 with SD of 12%. At a median follow-up of 18 months (interquartile range, 11-26 months), the primary endpoint occurred in 93 patients (60 deaths and 35 MACEs) and 221 patients underwent surgical or transcatheter aortic valve replacement (AVR). In the entire cohort, separate multivariable models adjusted for age, Charlson index, symptomatic status, time-dependent AVR, AS-severity, LA volume index and LVEF demonstrated that only LASr was associated with MACE+ACD (Hazard ratio, 0.97; P = 0.014). Subgroup analysis for MACE+ACD demonstrated consistent prognostication for LASr in moderate and severe AS; LVGLS was prognostic only in severe AS (all P ≤ 0.023). The optimal MACE+ACD cutoff for LASr from spline curves was 21.3%. Adjusted Kaplan-Meier curves demonstrated better event-free survival in patients with LASr >21.3% versus those with LASr ≤21.3% (P = 0.04).

CONCLUSIONS

In both moderate and severe AS, only LASr robustly predicted outcomes; thus, including LASr in the AS staging algorithm should be considered.

Left ventricular global work index and prediction of cardiovascular mortality after transcatheter aortic valve implantation

INTRODUCTION

Echocardiography is used for assessment of patients after transcatheter aortic valve implantation (TAVI). Global work index (GWI) integrates LV deformation throughout the cardiac cycle and LV afterload and may be advantageous for long-term follow-up.

METHODS

We analysed 144 patients with severe aortic stenosis who underwent TAVI and echocardiography within two weeks afterwards. GE EchoPAC v2.6 was applied for determining LV ejection fraction, global longitudinal strain (GLS), stroke work (SW), cardiac power output (CPO), and GWI. The endpoint was cardiovascular mortality.

RESULTS

During median follow-up of 625 [IQR: 511-770] days, 20 (14%) patients died. Clinical baseline characteristics were comparable between non-survivors and survivors. GWI (p = 0.003) and LVEF (p = 0.039) were lower in non-survivors, while GLS, SW, and CPO were not different. In Kaplan-Meier analysis patients with GWI ≤1234 mmHg% exhibited a lower survival probability (P = 0.006). In univariable Cox regression, a significant mortality association was identified for GWI (P = 0.004), weaker for LVEF (P = 0.014), but not for the other parameters. In multivariable Cox regression, GWI independently improved an LV systolic function model including LVEF and GLS. Similarly, GWI but not LVEF independently improved outcome association of different clinical models.

CONCLUSIONS

GWI was lower in non-survivors than survivors, differentiated non-survivors from survivors, was associated with mortality independent of clinical or LV parameters, and improved the fitness of clinical or LV prediction models. In contrast, GLS, SW, and CPO did not show any of these properties. GWI provides added value for follow-up after TAVI possibly by integrating LV deformation throughout the cardiac cycle.

Evolution of non-invasive myocardial work variables after transcatheter aortic valve implantation in patients with severe aortic stenosis

INTRODUCTION

Guidelines recommend aortic valve replacement in patients with severe aortic stenosis who present with symptoms or left ventricular ejection fraction<50%, both conditions representing a late stage of the disease. Whereas global longitudinal strain is load dependent, but interesting for assessing prognosis, myocardial work has emerged.

AIM

To evaluate acute changes in myocardial work occurring in patients undergoing transcatheter aortic valve implantation (TAVI).

METHODS

Patients who underwent TAVI were evaluated before and after by echocardiography. Complete echocardiographies were considered. Myocardial work indices (global work index, global constructive work, global work efficiency, global wasted work) were calculated integrating mean transaortic pressure gradient and brachial cuff systolic pressure.

RESULTS

One hundred and twenty-five patients underwent successful TAVI, with a significant decrease in mean transaortic gradient (from 52.5±16.1 to 12.2±5.0; P<0.0001). There was no significant change in left ventricular ejection fraction after TAVI. Myocardial work data after TAVI showed a significant reduction in global work index (1389±537 vs. 2014±714; P<0.0001), global constructive work (1693±543 vs. 2379±761; P<0.0001) and global work efficiency (85.0±7.06 vs. 87.1±5.98; P=0.0034). The decrease in global work index and global constructive work after TAVI was homogeneous among different subgroups, based on global longitudinal strain, left ventricular ejection fraction and New York Heart Association status before TAVI. We observed a significant association between global work index and global constructive work before TAVI, and global longitudinal strain degradation after TAVI.

CONCLUSIONS

Myocardial work variables show promising potential in best understanding the left ventricular myocardial consequences of aortic stenosis and its correction. Given their ability to discriminate between New York Heart Association status and global longitudinal strain evolution, we can hypothesize about their clinical value.

Prognostic impact of left ventricular systolic dysfunction in patients with mixed aortic valve disease undergoing aortic valve replacement

BACKGROUND

The implications of left ventricular remodeling and dysfunction before and after aortic valve replacement (AVR) for mixed aortic valve disease (MAVD) are not well understood. This study aims to evaluate the impact of AVR on left ventricular (LV) systolic function in MAVD, and determine the prognostic value of postoperative LV global longitudinal strain (LV-GLS) and LV ejection fraction (LVEF).

METHODS

We retrospectively assessed 489 consecutive patients with MAVD (defined as at least moderate aortic stenosis and at least moderate aortic regurgitation) and baseline LVEF ≥50%, who underwent AVR between February 2003 and August 2018. All patients had baseline echocardiography, whereas 192 patients underwent postoperative echocardiography between 3 and 18 months after AVR. The primary endpoint was all-cause mortality.

RESULTS

Mean age was 65 ± 15 years, and 65% were male. AVR in MAVD patients has a neutral effect on LV systolic function quantitated by LVEF and LV-GLS. During a median follow-up period of 5.8 years, 65 patients (34%) of 192 patients with follow-up echocardiography died. The patients with postoperative LVEF ≥50% had better survival than those with postoperative LVEF <50% (P < .001). Furthermore, among patients with postoperative LVEF ≥50%, mortality differed between patients with postoperative LV-GLS worse than -15% and those with postoperative LV-GLS better than -15% (P < .001).

CONCLUSIONS

In patients with MAVD who underwent AVR, the mean postoperative LV-GLS and LVEF remain at a similar value to baseline. However, worse postoperative LV-GLS and LVEF were both independently associated with higher mortality in this population.

Post-cardiopulmonary bypass longitudinal strain provides higher prognostic ability than baseline strain or change in strain

CONTEXT

Global longitudinal strain (GLS) measured by speckle-tracking echocardiography demonstrates excellent prognostic ability in predicting major adverse cardiac events after cardiac surgery. However, the optimal timing of intraoperative GLS measurement that provides the best prognostic value is unclear.

AIM

Our goal was to evaluate whether GLS measured prior to cardiopulmonary bypass (pre-CPB GLS), following CPB (post-CPB GLS), or change in GLS provides the strongest association with postoperative complications.

SETTING AND DESIGN

Post hoc analysis of prospectively collected data from a clinical trial (NCT01187329). 72 patients with aortic stenosis undergoing elective AVR ± coronary artery bypass grafting between January 2011 and August 2013.

MATERIAL AND METHODS

Myocardial deformation analysis from standardized transesophageal echocardiographic examinations were performed after anesthetic induction and chest closure. We evaluated the association between pre-CPB GLS, post-CPB GLS, and change in GLS (percent change from pre-CPB baseline) with postoperative atrial fibrillation and hospitalization >7 days. The association of post-CPB GLS with duration of mechanical ventilation, N-terminal pro-BNP (NT-proBNP) and troponin T were also assessed.

STATISTICAL ANALYSIS

Multivariable logistic regression.

RESULTS

Risk-adjusted odds (OR[97.5%CI] of prolonged hospitalization increased an estimated 27% (1.27[1.01 to 1.59];P_adj =0.035) per 1% decrease in absolute post-CPB GLS. Mean[98.3%CI] NT-proBNP increased 98.4[20 to 177]pg/mL; P_adj =0.008), per 1% decrease in post-CPB GLS. Pre-CPB GLS or change in GLS were not associated with any outcomes.

CONCLUSIONS

Post-CPB GLS provides the best prognostic value in predicting postoperative outcomes. Measuring post-CPB GLS may improve risk stratification and assist in future study design and patient outcome research.

Current and new imaging techniques in risk stratification of asymptomatic severe aortic stenosis

Aortic stenosis (AS) is one of the most common valvular diseases in clinical practice. The prevalence of calcified AS with moderate or severe stenosis exceeds 2% after 75 years. The optimal timing of intervention for asymptomatic severe AS is uncertain and controversial. Identification of high-risk patients is based on echocardiographic parameters (left ventricular dysfunction, AS severity and progression), hemodynamic response to exercise, pulmonary hypertension, and elevated brain natriuretic peptides. However, early surgical aortic valve replacement (AVR), when compared to the watchful waiting approach, was associated with survival advantage. Moreover, new insights into pathophysiology of AS and advances in imaging modalities were helpful in the management of asymptomatic AS. In this report, we detail the potential role of echocardiography to guide timing of surgery and we discussed the use of early risk features based on recent imaging modalities.

Left Ventricular Mechanics Differ in Subtypes of Aortic Stenosis Following Transcatheter Aortic Valve Replacement

Background

Left ventricular (LV) mechanics are impaired in patients with severe aortic stenosis (AS). We hypothesized that there would be differences in myocardial mechanics, measured by global longitudinal strain (GLS) recovery in patients with four subtypes of severe AS after transcatheter aortic valve replacement (TAVR), stratified based upon flow and gradient.

Methods

We retrospectively evaluated 204 patients with severe AS who underwent TAVR and were followed post-TAVR at our institution for clinical outcomes. Speckle-tracking transthoracic echocardiography was performed pre- and post-TAVR. Patients were classified as: (1) normal-flow and high-gradient, (2) normal-flow and high-gradient with reduced LV ejection fraction (LVEF), (3) classical low-flow and low-gradient, or (4) paradoxical low-flow and low-gradient.

Results

Both GLS (−13.9 ± 4.3 to −14.8 ± 4.3, P < 0.0001) and LVEF (55 ± 15 to 57 ± 14%, P = 0.0001) improved immediately post-TAVR. Patients with low-flow AS had similar improvements in LVEF (+2.6 ± 9%) and aortic valve mean gradient (−23.95 ± 8.34 mmHg) as patients with normal-flow AS. GLS was significantly improved in patients with normal-flow (−0.93 ± 3.10, P = 0.0004) compared to low-flow AS. Across all types of AS, improvement in GLS was associated with a survival benefit, with GLS recovery in alive patients (mean GLS improvement of −1.07 ± 3.10, P < 0.0001).

Conclusions

LV mechanics are abnormal in all patients with subtypes of severe AS and improve immediately post-TAVR. Recovery of GLS was associated with a survival benefit. Patients with both types of low-flow AS showed significantly improved, but still impaired, GLS post-TAVR, suggesting underlying myopathy that does not correct post-TAVR.

Myocardial work assessment in severe aortic stenosis undergoing transcatheter aortic valve replacement

AIMS

Myocardial work is a novel echocardiographic algorithm that corrects speckle-tracking-derived global longitudinal strain (GLS) for afterload using non-invasive systolic blood pressure as a surrogate for left ventricular systolic pressure (LVSP). Yet, in patients with severe aortic stenosis, non-invasive systolic blood pressure does not equal LVSP.

METHODS AND RESULTS

We evaluated 35 patients with severe aortic stenosis who underwent transcatheter aortic valve replacement (TAVR). Transthoracic echocardiography, including myocardial mechanics, was performed pre- and post-TAVR. We performed simultaneous echocardiographic and cardiac catheterization measurements in 23 of the 35 patients at the time of TAVR. Peak and mean aortic gradients were calculated from echocardiographic and cardiac catheterization data. Peak-to-peak LV-aortic gradient correlated highly with mean LV-aortic gradient (r = 0.96); measured LVSP correlated highly with our novel method of non-invasively estimated LVSP (non-invasive systolic blood pressure cuff + Doppler-derived mean aortic gradient, r = 0.92). GLS improved from pre- to post-TAVR (-14.2% ± 4.3 vs. -15.1% ± 3.2), and myocardial work reduced from corrected pre-TAVR to post-TAVR (global work index: 1856.2 mmHg% ± 704.6 vs. 1534.8 ± 385.0).

CONCLUSION

We propose that non-invasive assessment of myocardial work can be reliably performed in aortic stenosis by the addition of mean aortic gradient to non-invasive systolic blood pressure. From this analysis, we note the novel and unique finding that GLS can improve as myocardial work reduces post-TAVR in patients with severe aortic stenosis. Both GLS and myocardial work post-TAVR remain below normal values, requiring further studies.

The determinants of plasma brain natriuretic peptide level in severe aortic valve stenosis patients undergoing transcatheter aortic valve implantation

BACKGROUND

Brain or B-type natriuretic peptide (BNP) is an objective marker to diagnose the presence of heart failure (HF) and assess its severity. However, the determinants of serum BNP level in elderly patients with severe aortic valve stenosis (AS) referred for transcatheter aortic valve implantation (TAVI) have not been well investigated.

METHODS

We prospectively studied 106 AS patients who underwent TAVI. Cardiac catheterization, transesophageal echocardiography, and blood collection for plasma BNP level measurements were performed simultaneously just before the TAVI procedures.

RESULTS

Ninety-nine patients (83.9±5.0 years, 33% male) were studied. The natural logarithm of BNP (lnBNP) level was 5.4±0.9 pg/mL. Significant correlations with lnBNP level were observed in: 1) the history of syncope, prior HF medication, and New York Heart Association class III or IV (R=0.255, p=0.011) (R=0.210, p=0.037) (R=0.402, p<0.001), 2) albumin and hemoglobin level (R=-0.289, p=0.004) (R=0.263, p=0.009), 3) Left ventricular (LV) ejection fraction and global longitudinal strain (LVGLS) (R=-0.338, p<0.001) (R=0.447, p<0.001), 4) LV end-diastolic volume index (EDVI), LV mass index, and left atrial volume index (R=0.280, p=0.005) (R=0.366, p<0.001) (R=0.337, p<0.001), 5) the catheter-measured pressure gradient across the aortic valve (AVPG) (R=0.365, p<0.001). Note that LV wall stress was not significantly correlated with lnBNP level. LVGLS, AVPG, hemoglobin level, and LVEDVI were independently correlated with ln BNP level (R=0.652, LVGLS; β=0.395, p<0.006, AVPG; β=0.291, p=0.001, hemoglobin level; β=-0.216, p=0.011, and LVEDVI; β=0.203, p=0.016, respectively).

CONCLUSIONS

In severe AS patients candidate for TAVI, multiple factors, including the severities of AS and HF conditions and subclinical LV dysfunction determined by LVGLS affects plasma BNP level.

Left ventricular twist predicts mortality in severe aortic stenosis

OBJECTIVE

Left ventricular (LV) twist is a major component of ventricular mechanics reflecting the helical orientation of cardiac fibres and compensating for afterload mismatch. However, it is not known whether it determines outcome after transcatheter aortic valve implantation (TAVI). This study sought to investigate TAVI-induced short-term changes of LV twist and to define its role in outcome prediction.

METHODS

A total of 146 patients (median age 81.78 years, 50.7% male) undergoing TAVI for severe aortic stenosis were included. LV rotation and twist were determined by speckle tracking echocardiography within 3 months before and 2 weeks after TAVI. All-cause mortality at 2 years was defined as primary end point.

RESULTS

Patients who survived exhibited a higher apical peak systolic rotation (APSR) (p<0.001), twist (p=0.003) and torsion (p=0.019) pre-TAVI compared with those who died (n=22). Within 2 weeks after TAVI, APSR, twist and torsion decreased in patients who survived (all p<0.001), while no change occurred in those who died. Cox regression analysis showed an association of pre-TAVI APSR (HR 0.92, p=0.010), twist (HR 0.93, p=0.018) and torsion (HR 0.68, p=0.040) with all-cause mortality and an even stronger association of the respective changes after TAVI (∆APSR: HR 1.15, p<0.001; ∆twist: HR 1.14, p<0.001; ∆torsion: HR 2.53, p<0.001). All the parameters determined outcome independently of global longitudinal strain (GLS) and LV ejection fraction (LVEF).

CONCLUSION

APSR, twist and torsion pre-TAVI as well as their change within 2 weeks after TAVI predict 2-year all-cause mortality after TAVI, adding incremental prognostic value to LVEF and GLS.

Left Ventricular Longitudinal Strain in Characterization and Outcome Assessment of Mixed Aortic Valve Disease Phenotypes

OBJECTIVES

The aims of this study were to characterize the interplay between mixed aortic valve disease (MAVD) phenotypes (defined by concomitant severities of aortic stenosis and aortic regurgitation) and left ventricular global longitudinal strain (LV-GLS), and to assess the prognostic utility of LV-GLS in MAVD.

BACKGROUND

Little is known about the way LV-GLS separates MAVD phenotypes and if it is associated with their outcomes.

METHODS

This observational cohort study evaluated 783 consecutive adult patients with left ventricular ejection fraction ≥50% and MAVD, which was defined as coexisting with at least moderate aortic stenosis and at least moderate aortic regurgitation. We measured the conventional echocardiographic variables and average LV-GLS from apical long, 2- and 4-chamber views. The primary endpoint was all-cause mortality.

RESULTS

Mean age of patients was 69 ± 15 years, and 58% were male. Mean LV-GLS was -14.7 ± 2.9%. In total, 458 patients (59%) underwent aortic valve replacement at a median period of 50 days (25th to 75th percentile range: 6 to 560 days). During a median follow-up period of 5.6 years (25th to 75th percentile range: 1.8 to 9.4 years), 391 patients (50%) died. When stratified patients into tertiles according to LV-GLS values, patients with worse LV-GLS had worse outcomes (p < 0.001). LV-GLS was independently associated with mortality (hazard ratio: 1.09; 95% confidential intervals: 1.04 to 1.14; p < 0.001), with the relationship between LV-GLS and mortality being linear.

CONCLUSIONS

LV-GLS is associated with all-cause mortality. LV-GLS may be useful for risk stratification in patients with MAVD.

Association of Natriuretic Peptide Levels After Transcatheter Aortic Valve Replacement With Subsequent Clinical Outcomes

Importance

Among those with aortic stenosis, natriuretic peptide levels can provide risk stratification, predict symptom onset, and aid decisions regarding the timing of valve replacement. Less is known about the prognostic significance and potential clinical utility of natriuretic peptide levels measured after valve replacement.

Objective

To determine the associations of elevated B-type natriuretic peptide (BNP) levels after transcatheter aortic valve replacement (TAVR) and change in BNP levels between follow-up time points with risk of subsequent clinical outcomes.

Design, Setting, and Participants

In this cohort study, patients with severe symptomatic aortic stenosis at intermediate, high, or prohibitive surgical risk for aortic valve replacement who underwent TAVR from the PARTNER IIA cohort, PARTNER IIB cohort, SAPIEN 3 intermediate-risk registry, and SAPIEN 3 high-risk registry were included. B-type natriuretic peptide levels were obtained at baseline and discharge as well as 30 days and 1 year after TAVR. For each measurement, a BNP ratio was calculated using measured BNP level divided by the upper limit of normal for the assay used. Outcomes were evaluated in landmark analyses out to 2 years. Data were collected from April 2011 to January 2019.

Main Outcomes and Measures

All-cause death, cardiovascular death, rehospitalization, and the combined end point of cardiovascular death or rehospitalization.

Results

Among 3391 included patients, 1969 (58.1%) were male, and the mean (SD) age was 82 (7.5) years. Most patients had a BNP ratio greater than 1 at each follow-up time point, including 2820 of 3256 (86.6%) at baseline, 2652 of 2995 (88.5%) at discharge, 1779 of 2209 (80.5%) at 30 days, and 1799 of 2391 (75.2%) at 1 year. After adjustment, every 1-point increase in BNP ratio at 30 days (approximately equivalent to an increase of 100 pg/mL in BNP) was associated with an increased hazard of all-cause death (adjusted hazard ratio [aHR], 1.11; 95% CI, 1.07-1.15), cardiovascular death (aHR, 1.16; 95% CI, 1.11-1.21), and rehospitalization (aHR, 1.08; 95% CI, 1.03-1.14) between 30 days and 2 years. Among those with a BNP ratio of 2 or more at discharge, after adjustment, every 1-point decrease in BNP ratio between discharge and 30 days was associated with a decreased hazard of all-cause death (aHR, 0.92; 95% CI, 0.88-0.96) between 30 days and 2 years.

Conclusions and Relevance

Elevated BNP levels after TAVR was independently associated with increased subsequent mortality and rehospitalizations. Further studies to determine how best to mitigate this risk are warranted.

Clinical Applications of Echo Strain Imaging: a Current Appraisal

PURPOSE OF REVIEW

This article reviews recent advances in echocardiographic strain imaging, particularly in its ability to prognosticate in cardiovascular outcomes and impact clinical decision making.

RECENT FINDINGS

Strain has been proposed as a sensitive tool in detecting early ventricular dysfunction. Left ventricular global longitudinal strain (LV-GLS) detects subtle changes in myocardial function, often not quantifiable by ejection fraction alone. Thus, LV-GLS provides the opportunity for early decision-making, and the implementation of more effective treatments, improving outcomes in a variety of diseases such as valvular heart diseases, cardio-oncology, ischemic heart disease, cardiomyopathies, heart transplantation, and pericardial diseases and cardiomyopathies. Strain is a promising tool for the early detection of myocardial dysfunction in patients with preserved left ventricular ejection fraction and can prognosticate long-term outcomes.

GDF-15 (Growth Differentiation Factor 15) Is Associated With Lack of Ventricular Recovery and Mortality After Transcatheter Aortic Valve Replacement

BACKGROUND

Recent data suggest that circulating biomarkers may predict outcome in patients undergoing transcatheter aortic valve replacement (TAVR). We examined the association between inflammatory, myocardial, and renal biomarkers and their role in ventricular recovery and outcome after TAVR.

METHODS AND RESULTS

A total of 112 subjects undergoing TAVR were included in the prospective registry. Plasma levels of B-type natriuretic peptide, hs-TnI (high-sensitivity troponin I), CRP (C-reactive protein), GDF-15 (growth differentiation factor 15), GAL-3 (galectin-3), and Cys-C (cystatin-C) were assessed before TAVR and in 100 sex-matched healthy controls. Among echocardiographic parameters, we measured global longitudinal strain, indexed left ventricular mass, and indexed left atrial volume. The TAVR group included 59% male, with an average age of 84 years, and 1-year mortality of 18%. Among biomarkers, we found GDF-15 and CRP to be strongly associated with all-cause mortality (P<0.001). Inclusion of GDF-15 and CRP to the Society of Thoracic Surgeons score significantly improved C index (0.65-0.79; P<0.05) and provided a category-free net reclassification improvement of 106% at 2 years (P=0.01). Among survivors, functional recovery in global longitudinal strain (>15% improvement) and indexed left ventricular mass (>20% decrease) at 1 year occurred in 48% and 22%, respectively. On multivariate logistic regression, lower baseline GDF-15 was associated with improved global longitudinal strain at 1 year (hazard ratio=0.29; P<0.001). Furthermore, improvement in global longitudinal strain at 1 month correlated with lower overall mortality (hazard ratio=0.45; P=0.03).

CONCLUSIONS

Elevated GDF-15 correlates with lack of reverse remodeling and increased mortality after TAVR and improves risk prediction of mortality when added to the Society of Thoracic Surgeons score.

Novel Echocardiographic Parameters in Patients With Aortic Stenosis and Preserved Left Ventricular Systolic Function Undergoing Surgical Aortic Valve Replacement

We sought to study the incremental prognostic impact of baseline valvuloarterial impedance (Zva) and left ventricular global longitudinal strain (LV-GLS) in patients with severe aortic stenosis and preserved left ventricular ejection fraction (LVEF) treated with surgical aortic valve replacement (AVR). We included 961 consecutive patients (68 ± 13 years; 63% men) with severe aortic stenosis (indexed aortic valve area <0.6 cm²) and LVEF >50% who underwent surgical AVR at our institution between January 2007 and December 2008. The analysis is based on derivation (n = 637) and validation (n = 324) subgroups. Society of Thoracic Surgeons (STS) score was calculated. Zva (systolic arterial pressure + mean aortic valve gradient)/left ventricular stroke volume index and LV-GLS (measured offline using Velocity Vector Imaging; Siemens Medical Solutions, Mountain View, California) were calculated. The primary outcome was death. Median Zva and LV-GLS were 4.5 mm Hg × ml^-1× m² and -14.5%, respectively. AVR was performed at a median of 34 days from initial evaluation (isolated AVR in 46%, bioprosthetic AVR in 93%). At 7.5 ± 3 years, 320 patients died (33%; 30 days/in-hospital death in 0.5%). In the derivation subgroup, on multivariate Cox survival analysis, higher STS score (hazard ratio [HR] 1.06), higher Zva (HR 1.13), and worse LV-GLS (HR 1.07) were independently associated with long-term survival (all p <0.01). When Zva and LV-GLS were sequentially added to STS score, the c-statistic improved from 0.63 [0.55 to 0.77] to 0.70 [0.60 to 0.81] and 0.78 [0.69 to 0.83], respectively, all p <0.001). Findings were confirmed in the validation subgroup. In conclusion, in patients with severe aortic stenosis and preserved LVEF treated with surgical AVR, baseline Zva and LV-GLS provide improved risk stratification with synergistic prognostic value.

Outcomes in Asymptomatic Severe Aortic Stenosis With Preserved Ejection Fraction Undergoing Rest and Treadmill Stress Echocardiography

Background

In asymptomatic patients with severe aortic stenosis and preserved left ventricular ejection fraction, we sought to assess the incremental prognostic value of resting valvuloarterial impedence (Zva) and left ventricular global longitudinal strain (LV‐GLS) to treadmill stress echocardiography.

Methods and Results

We studied 504 such patients (66±12 years, 78% men, 32% with coronary artery disease who underwent treadmill stress echocardiography between 2001 and 2012. Clinical and exercise variables (% of age‐sex predicted metabolic equivalents [%AGP‐METs]) were recorded. Resting Zva ([systolic arterial pressure+mean aortic valve gradient]/[LV‐stroke volume index]) and LV‐GLS (measured offline using Velocity Vector Imaging, Siemens) were obtained from the baseline resting echocardiogram. Death was the primary outcome. There were no major adverse cardiac events during treadmill stress echocardiography. Indexed aortic valve area, Zva, and LV‐GLS were 0.46±0.1 cm²/m², 4.5±0.9 mm Hg/mL per m² and −16±4%, respectively; only 50% achieved >100% AGP‐METs. Sixty‐four percent underwent aortic valve replacement. Death occurred in 164 (33%) patients over 8.9±3.6 years (2 within 30 days of aortic valve replacement). On multivariable Cox survival analysis, higher Society of Thoracic Surgeons score (hazard ratio or HR 1.06), lower % AGP‐METS (HR 1.16), higher Zva (HR 1.25) and lower LV‐GLS (HR 1.12) were associated with higher longer‐term mortality, while aortic valve replacement (HR 0.45) was associated with improved survival (all P<0.01). Sequential addition of ZVa and LV‐GLS to clinical model (Society of Thoracic Surgeons score and %AGP‐METs) increased the c‐statistic from 0.65 to 0.69 and 0.75, respectively, both P<0.001); findings were similar in the subgroup of patients who underwent aortic valve replacement.

Conclusions

In asymptomatic patients with severe aortic stenosis undergoing treadmill stress echocardiography, LV‐GLS and ZVa offer incremental prognostic value.

Reversibility of Cardiac Function Predicts Outcome After Transcatheter Aortic Valve Replacement in Patients With Severe Aortic Stenosis

Background

Reversibility of left ventricular (LV) dysfunction in high‐risk aortic stenosis patient and its impact on survival after transcatheter aortic valve replacement (TAVR) are unclear. We aimed to evaluate longitudinal changes of LV structure and function after TAVR and their impact on survival.

Methods and Results

We studied 209 patients with aortic stenosis who underwent TAVR from May 2006 to December 2012. Echocardiograms were used to calculate LV end‐diastolic volume index (LVEDVi), LV ejection fraction, LV mass index (LVMi), and global longitudinal strain before, immediately (<10 days), late (1–3 months), and yearly after TAVR. During a median follow‐up of 1345 days, 118 patients died, with 26 dying within 1 year. Global longitudinal strain, LVEDVi, LV ejection fraction, and LVMi improved during follow‐up. In patients who died during the first year, death was preceded by LVEDVi and LVMi increase. Multivariable longitudinal data analysis showed that aortic regurgitation at baseline, aortic regurgitation at 30 days, and initial LVEDVi were independent predictors of subsequent LVEDVi. In a joint analysis of longitudinal and survival data, baseline Society of Thoracic Surgeons score was predictive of survival, with no additive effect of longitudinal changes in LVEDVi, LVMi, global longitudinal strain, or LV ejection fraction. Presence of aortic regurgitation at 1 month after TAVR was the only predictor of 1‐year survival.

Conclusions

LV reverse remodeling was observed after TAVR, whereas lack of LVEDVi and LVMi improvement was observed in patients who died during the first year after TAVR. Post‐TAVR, aortic regurgitation blocks reverse remodeling and is associated with poor 1‐year survival after TAVR.

Increased Left Ventricular Diastolic Stiffness Is Associated With Heart Failure Symptoms in Aortic Stenosis Patients With Preserved Ejection Fraction

BACKGROUND

Clinical risk factors associated with heart failure (HF) symptoms in aortic stenosis (AS) patients with preserved ejection fraction (EF) have not been fully identified. We hypothesized that left ventricular (LV) diastolic stiffness is associated with HF symptoms in patients with AS.

METHODS AND RESULTS

We retrospectively evaluated 275 patients with at least moderate AS (aortic valve area <1.5 cm²) and preserved EF (≥50%). LV diastolic stiffness was evaluated with the use of echocardiographic parameters, diastolic wall strain (DWS, a measure of LV wall stiffness), and K_LV (a marker of LV chamber stiffness). There were 69 patients with HF. Patients with HF were older, were more likely to be African American, had a higher body mass index, and had more hypertension and coronary artery disease (P < .05 for all). Aortic valve area index and mean pressure gradient across the aortic valve were not different between patients with and without HF. Despite similar echocardiographic parameters of AS severity, patients with HF had stiffer LV (DWS 0.21 ± 0.06 vs 0.25 ± 0.06 [P < .01], K_LV 0.17 ± 0.11 vs 0.13 ± 0.08 [P < .01]). Logistic regression analyses revealed that after adjusting for age, race, body mass index, history of hypertension, and coronary artery disease, LV diastolic stiffness parameters remained significantly associated with HF symptoms.

CONCLUSIONS

LV diastolic stiffness is independently associated with HF in AS patients with preserved EF.

Medical Treatment of Aortic Stenosis

Untreated, severe, symptomatic aortic stenosis is associated with a dismal prognosis. The only treatment shown to improve survival is aortic valve replacement; however, before symptoms occur, aortic stenosis is preceded by a silent, latent phase characterized by a slow progression at the molecular, cellular, and tissue levels. In theory, specific medical therapy should halt aortic stenosis progression, reduce its hemodynamic repercussions on left ventricular function and remodeling, and improve clinical outcomes. In the present report, we performed a systematic review of studies focusing on the medical treatment of patients with aortic stenosis. Lipid-lowering therapy, antihypertensive drugs, and anticalcific therapy have been the main drug classes studied in this setting and are reviewed in depth. A critical appraisal of the preclinical and clinical evidence is provided, and future research avenues are presented.

Severe and Asymptomatic Aortic Stenosis Management Challenge: Knowing That We Do Not Really Know

OPINION STATEMENT

The clinical management of asymptomatic patients with severe aortic valve stenosis (AS) may be challenging. Indeed, there is substantial controversy over the optimal timing of intervention for these patients, as some advocate early intervention while others urge for a conservative management until symptom onset. In the meantime of randomized clinical trials aiming to compare both strategies of management, an integrative approach including several imaging modalities as well as biomarkers of the myocardial damage may help to improve the risk stratification of patients with asymptomatic severe AS and individualize strategy of treatment. The extent of aortic valve calcification, semi-quantitatively assessed by echocardiography but better fully quantitatively measured by computed tomography (CT), provides incremental value to predict rapid disease progression and adverse event and thus could be a potential trigger for early referral to intervention or guide the timing of clinical follow-up. In addition, the assessment of disease activity using positron emission tomography, combined with CT calcium scoring, may also help to better predict the disease progression. The comprehensive assessment of left ventricular (LV) function using speckle-tracking echocardiography and/or cardiac magnetic resonance may provide useful information regarding the actual repercussion of AS on the myocardium. Besides imaging modalities, the measurement of several circulating biomarkers associated with the extent of the myocardial damage may also improve the risk stratification of asymptomatic patients with severe AS and help guiding management. Finally, it should be emphasized that a personalized medicine, including this comprehensive integrative approach in heart valve clinics, should be advocated for the management of these challenging patients.