Recovery of Left Ventricular Systolic Longitudinal Strain After Valve Replacement in Aortic Stenosis and Relation to Natriuretic Peptides

Improving assessment of aortic stenosis

"Degenerative" or calcific aortic stenosis is a complex, multifaceted, systemic disease that is not solely limited to the aortic valve but also includes reduced arterial compliance as well as alterations of left ventricular geometry and function. This particular nature of the disease underscores the need for a more comprehensive evaluation of disease severity going beyond the standard parameters routinely used to assess stenosis severity (i.e., peak jet velocity, pressure gradients, valve effective orifice area) or left ventricle function (i.e., left ventricular ejection fraction). The present paper thus proposes to review newer approaches to improve the quantification of disease severity taking into account the interrelation between the different valvular, arterial, and ventricular variables that may be responsible for the appearance of symptoms and/or poorer prognosis in patients with aortic stenosis.

Global Strain in Severe Aortic Valve Stenosis

Background—

Global longitudinal systolic strain (GLS) is often reduced in aortic stenosis despite normal ejection fraction. The importance of reduced preoperative GLS on long-term outcome after aortic valve replacement is unknown.

Methods and Results—

A total of 125 patients with severe aortic stenosis and ejection fraction >40% scheduled for aortic valve replacement were evaluated preoperatively and divided into 4 groups according to GLS quartiles. Patients were followed up for 4 years. The primary end points were major adverse cardiac events (MACEs) defined as cardiovascular mortality and cardiac hospitalization because of worsening of heart failure; the secondary end point was cardiovascular mortality. MACE and cardiac mortality were significantly increased in patients with lower GLS. Estimated 5-year MACE was increased: first quartile 19% (n=6) / second quartile 20% (n=6) / third quartile 35% (n=11) / fourth quartile 49% (n=15); P =0.04. Patients with increased age, left ventricular hypertrophy, and left atrial dilatation were at increased risk. In Cox regression analysis, after correcting for standard risk factors and ejection fraction, GLS was found to be significantly associated with cardiac morbidity and mortality. In a stepwise Cox model with forward selection, GLS was the sole independent predictor: hazard ratio=1.13 (95% confidence interval, 1.02–1.25), P =0.04. Comparing the overall log likelihood χ 2 of the predictive power of the multivariable model containing GLS was statistically superior to models based on EuroScore, history with ischemic heart disease, and ejection fraction.

Conclusions—

In patients with symptomatic severe aortic stenosis undergoing aortic valve replacement, reduced GLS provides important prognostic information beyond standard risk factors.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00294775.

Longitudinal left ventricular 2D strain is superior to ejection fraction in predicting myocardial recovery and symptomatic improvement after aortic valve implantation

BACKGROUND

Predicting improvement of myocardial function after transcatheter aortic valve implantation (TAVI) for aortic stenosis (AS) remains a challenge. As ejection fraction (EF) may be of limited value in detecting early myocardial dysfunction and predicting outcome, we assessed the potential of echocardiographic longitudinal function in this setting.

MATERIALS AND METHODS

Left ventricular (LV) function was assessed using EF, mitral annular plane systolic excursion (MAPSE), peak longitudinal 2D strain (LS) and strain rate (SR) in101consecutive patients with severe symptomatic AS (age 81 ± 11 years) undergoing TAVI. Echocardiography and assessment of clinical status including NYHA functional class were performed prior and after intervention (median 70 days).

RESULTS

Pre-interventional EF was 57 ± 17% and 32 patients (32%) had an EF<50% while 58 patients (57%) were found to have an impaired LS. After TAVI there was no significant change in EF. In contrast, LS, SR and MAPSE improved significantly (-14.0 ± 4.4 vs. -15.5 ± 4.0%; p=0.007, 0.68 ± 0.24 vs. 0.78 ± 0.23/s, p=0.002; and 9.1 ± 3.2 vs. 10.2 ± 3.3mm, p=0.006, respectively). Receiver Operating Curve characteristic analysis identified a pre-TAVI LS>-13.3% as the optimal cut-off value for predicting lack of LS recovery post TAVI. There was a marked improvement in NYHA FC after intervention (p=0.0002). Among the studied echocardiographic parameters LS change correlated closest with NYHA class improvement (r=0.42, p=0.0008).

CONCLUSION

Overall, LS appears to be more sensitive for detecting early myocardial damage in patients with AS compared to conventional echocardiographic parameters. More importantly, pre-interventional LS may identify irreversible myocardial dysfunction and LS improvement correlates with symptomatic improvement after intervention.

Systolic heart function remains depressed for at least 30 days after on-pump cardiac surgery

OBJECTIVES

The myocardial recovery time following on-pump cardiac surgery remains uncertain. Global peak longitudinal strain is a sensitive measure of endocardial function which is most susceptible to ischaemia. We aimed to evaluate changes in global peak longitudinal strain up to 6 months after surgery and to compare initial changes with alterations in troponin T. Secondarily, we aimed to describe perioperative changes in strain of the inter-ventricular septum when compared with reference segments.

METHODS

Patients scheduled for coronary bypass, aortic valve replacement or combination procedures were enrolled. Echocardiography was performed on the day before surgery, the day after surgery, 4 days after surgery, 30 days after surgery and 6 months after surgery. Troponin T was measured 3, 16 and 24 h following procedure.

RESULTS

Forty patients were enrolled and one was later excluded. Global peak longitudinal strain decreased from -14.5 ± 3.33% preoperatively to -9.98 ± 3.09% and -10.57 ± 3.16% on the first and fourth postoperative day, respectively. Global strain was still reduced on the 30th postoperative day, but had returned to preoperative values 6 months after surgery. Absolute values and relative changes in global strain did not correlate with postoperative peak troponin T measurements. Strain of the inter-ventricular septum was unaffected by surgery as opposed to reference segments, although septal displacement in the longitudinal direction decreased from 12.0 ± 3.75 mm preoperatively to 3.58 ± 4.22 mm 4 days after surgery.

CONCLUSIONS

Global peak longitudinal strain was reduced for at least 30 days after on-pump cardiac surgery and seems to represent a more sensitive marker of myocardial function than ejection fraction. The decrease in global strain was not reflected in troponin T measurements. The visual, echocardiographic impression of septal dysfunction may be a translational phenomenon, as septal strain was unaffected by surgery.

Reduced global longitudinal and radial strain with normal left ventricular ejection fraction late after effective repair of aortic coarctation: a CMR feature tracking study

We sought to determine whether global and regional left ventricular (LV) strain parameters were altered in repaired coarctation of the aorta (COA) with normal LV ejection fraction (EF) when compared with healthy adult controls, and whether such alterations were related to LV hypertrophy (LVH). We identified 81 patients after COA repair (31 female, age 25 ± 8.5 years) with inclusion criteria at follow-up CMR of: age ≥13 years, time post-repair ≥10 years, no aortic valve disease, LV-EF >50%). LV deformation indices derived using CMR-feature tracking and volumetric EF were compared between COA patients and normal controls (n = 20, 10 female, age 37 ± 7 years), and between COA with versus without LVH. In repaired COA versus controls, LV-EF (%) was 62 ± 7.2 versus 58 ± 3.0 (p = 0.01), and LV mass (g/m(2)) 66 ± 16.8 versus 57.7 ± 6.0 (p = 0.0001). LV global longitudinal strain (GLS) was decreased to -17.0 ± 4.7% in COA (-20 ± 5% in controls, p = 0.02), and global radial strain (GRS) reduced to 40 ± 15% (50 ± 12.4% in controls, p = 0.003). The global circumferential strain (GCS) was preserved in COA at -23 ± 4.7% (-24.6 ± 2.4% in controls, p = 0.14). Regionally, LS decrease was marked in the basal segments (septal, p = 0.005, lateral, p = 0.013). In COA with LVH (n = 45, mass 76.3 ± 12.8 g/m(2)) versus without LVH (n = 36, mass 52.2 ± 10 g/m(2)), GLS was more markedly decreased (-15.7 ± 4.8 vs. -18.5 ± 4.2%, p = 0.016, but GRS and GCS were similar (p = 0.49 and 0.27). In post-repair COA with normal LV-EF, GLS and GRS are reduced whilst GCS is preserved. GLS reduction is more pronounced in the presence of LVH. GLS may qualify as indicator of early LV dysfunction.

Acute regional improvement of myocardial function after interventional transfemoral aortic valve replacement in aortic stenosis: a speckle tracking echocardiography study

Background

Transcatheter aortic valve implantation (TAVI) is a promising therapy for patients with severe aortic stenosis (AS) and high perioperative risk. New echocardiographic methods, including 2D Strain analysis, allow the more accurate measurement of left ventricular (LV) systolic function. The goal of this study was to describe the course of LV reverse remodelling immediately after TAVI in a broad spectrum of patients with symptomatic severe aortic valve stenosis.

Methods

Thirty consecutive patients with symptomatic aortic valve stenosis and preserved LVEF underwent transfemoral aortic valve implantation. We performed echocardiography at baseline and one week after TAVI. Echocardiography included standard 2D and Doppler analysis of global systolic and diastolic function as well as 2D Strain measurements of longitudinal, radial and circumferential LV motion and Tissue Doppler echocardiography.

Results

The baseline biplane LVEF was 57 ± 8.2%, the mean pressure gradient was 46.8 ± 17.2 mmHg and the mean valve area was 0.73 ± 0.27 cm². The average global longitudinal 2D strain of the left ventricle improved significantly from -15.1 (± 3.0) to -17.5 (± 2.4) % (p < .001). This was reflected mainly in improvement in the basal and medial segments while strain in the apex did not change significantly [-11.6 (± 5.2) % to -15.1 (± 5.5) % (p < .001), -13.9 (± 5.1) % to -16.8 (± 5.6) % (p < .001) and -19.2 (± 7.0) % to -20.0 (± 7.2) % (p = .481) respectively]. While circumferential strain [-18.1 (± 5.1) % vs. -18.9 (± 4.2) %, p = .607], radial strain [36.5 (± 13.7) % vs. 39.7 (± 17.2) %, p = .458] and the LVEF remained unchanged after one week [57.0 (± 8.2) % vs. 59.1 (± 8.1) %, p = .116].

Conclusion

There is an acute improvement of myocardial longitudinal systolic function of the basal and medial segments measured by 2D Strain analysis immediately after TAVI. The radial, circumferential strain and LVEF does not change significantly in all patients acutely after TAVI. These data suggest that sensitive new echo methods can reliably detect early regional changes of myocardial function after TAVI before benefits in LVEF are detectable.

Global longitudinal strain in relation to the severity of aortic stenosis: a two-dimensional speckle-tracking study

BACKGROUND

Global longitudinal strain (GLS) measured by two-dimensional speckle tracking imaging (2D-STI) has been shown to be useful for assessing subtle change in left ventricular function in severe aortic stenosis (AS) patients with preserved left ventricular ejection fraction (LVEF). However, there is little information about the relation between the progression of AS and changes in GLS. The aim of this study was to evaluate the relation between the severity of valve stenosis and GLS measured by 2D-STI in AS patients with normal LVEF.

METHODS

We studied 113 AS patients (age, 73.3 ± 8.8 years; male, 38%; aortic valve area (AVA), 1.0 ± 0.3 cm(2); mean pressure gradient (PG), 33.8 ± 22.1 mmHg) with normal LVEF (≥50%) but without overt coronary artery disease. Patients were stratified into three groups (mild, moderate and severe AS), and the clinical characteristics and echocardiographic findings were compared among the groups. Using dedicated software, we measured GLS in the apical four-chamber view.

RESULTS

LVEF was not significantly different among the three groups. However GLS showed significant differences in GLS among the three groups (mild: 17.1 ± 3.0%, moderate: 16.4 ± 3.0% and severe: 14.5 ± 3.9%, ANOVA P = 0.003). GLS was significantly correlated with AVA, mean PG, LVEF, LV mass index and early diastolic mitral annular velocity (e'). In multiple stepwise regression analysis, mean PG, LVEF and hypertension were independently associated with GLS (R(2) = 0.247, P = 0.0001).

CONCLUSIONS

Despite unchanged LVEF, GLS gradually decreased as severity of AS increases. GLS measured by 2D-STI might be useful to assess subtle changes in LV function in AS patients. 

Relation of myocardial mechanics in severe aortic stenosis to left ventricular ejection fraction and response to aortic valve replacement

Decreased left ventricular (LV) longitudinal strain and increased circumferential LV strain have been demonstrated in patients with severe aortic stenosis (AS) and normal LV ejection fraction (LVEF). Biplane myocardial mechanics normalize after aortic valve replacement (AVR). This study objective was to examine LV mechanics before and soon after AVR in patients with AS and LV systolic dysfunction. Paired echocardiographic studies before and soon (7 ± 3 days) after AVR were analyzed in 64 patients with severe AS: 32 with normal LVEF (≥ 50%), 16 with mild to moderate LV dysfunction (LVEF <36% to 50%), and 16 with severe LV dysfunction (LVEF ≤ 35%). Longitudinal myocardial function was assessed from 3 apical views (average of 18 segments) and circumferential function was assessed at mid-LV and apical levels (average of 6 segments per view). Strain, strain rate, and mid-LV and apical rotations were measured using 2-dimensional velocity vector imaging. Before AVR (1) longitudinal strain was low in all patients and correlated with LVEF (ρ = 0.74, p <0.001), (2) mid-LV circumferential strain was supranormal in patients with normal LVEF and low in patients with low LVEF (ρ = 0.88, p <0.001), and (3) apical rotation was highest in patients with mild to moderate LV dysfunction. After AVR, LVEF increased in patients with LV dysfunction and myocardial mechanics partly normalized. In conclusion, compensatory mechanisms (high circumferential strain in patients with preserved LVEF and increased apical rotation in patients with mild to moderate LV dysfunction) were observed in patients with severe AS. Compensatory mechanics were lost in patients with severe LV dysfunction. AVR partly reversed these changes in patients with LV dysfunction.

Myocardial reverse remodeling

Despite an extensive literature defining the mechanisms and significance of pathological myocardial remodeling, there has been no comprehensive review of the inverse process, often labeled reverse remodeling. Accordingly, the goal of this review is to overview the varied settings in which clinically significant reverse remodeling has been well documented. When available, we reviewed relevant randomized, controlled clinical trials, and meta-analyses with sufficient cardiac imaging data to permit conclusions about reverse remodeling. When these types of studies were not available, relevant case-control studies and case series that employed appropriate methodology were reviewed. Regression of pathological myocardial hypertrophy, chamber shape distortions, and dysfunction occurs in a wide variety of settings. Although reverse remodeling occurs spontaneously in some etiologies of myocardial dysfunction and failure, remodeling is more commonly observed in response to medical, device-based, or surgical therapies, including β-blockers, revascularization, cardiac resynchronization therapy, and valve surgery. Indeed, reverse remodeling following pathophysiologically targeted interventions helps validate that the targeted mechanisms are propelling and/or sustaining pathological remodeling. The diverse clinical settings in which reverse remodeling has been observed demonstrates that myocardial remodeling is bidirectional and occurs across the full spectrum of myocardial disease severity, duration, and etiology. Observations in several settings suggest that recovered hearts are not truly normal despite parallel improvements at organ, tissue, and cellular level. Nevertheless, the link between reverse remodeling and improved outcomes should inspire further research to better understand the mechanisms responsible for both reverse remodeling and persistent deviations from normalcy.

Effect of candesartan treatment on left ventricular remodeling after aortic valve replacement for aortic stenosis

In hypertension, angiotensin receptor blockers can augment regression of left ventricular (LV) hypertrophy. It is not known whether this also is the case after aortic valve replacement (AVR) for severe aortic stenosis (AS). To test the hypothesis that treatment with candesartan in addition to conventional treatment is able to augment LV and left atrial (LA) reverse remodeling in patients with AS undergoing AVR, we studied 114 patients scheduled for AVR. Patients were randomized to treatment with candesartan 32 mg 1 time/day or conventional therapy immediately after AVR. Patients were followed with echocardiographic evaluations 3, 6, and 12 months after surgery. Primary end point was change in LV mass index. At baseline and during follow-up no differences in systolic, diastolic, and pulse pressures were seen between groups. Baseline LV mass index was 134 +/- 41 g/m(2) with no difference between groups. Mean decrease in LV mass index in the control group was 12 +/- 28 g/m(2) compared to 30 +/- 40 g/m(2) in the candesartan group (p = 0.015) during follow-up. After 12 months LV mass index was significantly lower in the candesartan group (103 +/- 29 vs 119 +/- 31 g/m(2), p = 0.01). In addition, the candesartan group had greater improvement in longitudinal LV systolic function assessed by tissue Doppler S' wave (0.6 +/- 0.1-cm/s increase in control group vs 1.4 +/- 0.1 cm/s in candesartan group, p = 0.01, p for trend = 0.02) and a decrease in LA volume (p for trend = 0.01). Treatment had no effect on diastolic E/e' ratio or B-type natriuretic peptide. In conclusion, angiotensin receptor blockade with candesartan after AVR in patients with AS is associated with augmented reverse LV and LA remodeling compared to conventional management.

Valve replacement for aortic stenosis normalizes subendocardial function in patients with normal ejection fraction

AIMS

Long-standing aortic stenosis (AS) causes various degrees of left ventricular (LV) dysfunction, which may improve after valve replacement. The aim of this study was to assess the nature of LV subendocardial abnormalities in AS and their response to valve replacement (AVR).

METHODS AND RESULTS

We studied 41 consecutive symptomatic patients (age 64 +/- 13 years) with severe AS, normal LV ejection fraction (EF), but no obstructive coronary artery disease before, a week after AVR, and 6 months after AVR. LV subendocardial function was studied from recordings of long-axis M-mode (amplitude), tissue-Doppler (myocardial velocities) and speckle tracking (myocardial strain) echocardiographic techniques. Results were compared with those from 20 age- and gender-matched controls. In patients, LV dimensions and markers of asynchrony, total isovolumic time (t-IVT), and Tei index were not different from controls before AVR and remained unchanged afterwards. LV lateral long-axis amplitude, as well as lateral and septal systolic velocities and strain, were reduced (P < 0.001 for all) and E/E' was modestly raised. Lateral long-axis amplitude, systolic and diastolic velocities normalized within a week of AVR but strain lagged behind until 6 months later. The reduced septal long-axis amplitude remained permanently unchanged (NS) despite the early normalization of its systolic velocities (P < 0.001) and strain (P < 0.001). LV mass normalized at 6 months after AVR (P < 0.005).

CONCLUSIONS

In patients with severe AS and maintained LV ejection fraction, subendocardial function is globally abnormal showing reduced amplitude of motion, velocities, and strain. The different response of its components suggests an evidence for differential reverse remodelling, irrespective of myocardial mass regression.

Left ventricular longitudinal systolic function after alcohol septal ablation for hypertrophic obstructive cardiomyopathy: a long-term follow-up study focused on speckle tracking echocardiography

AIMS

To examine left ventricular (LV) longitudinal systolic myocardial function in patients with hypertrophic obstructive cardiomyopathy (HOCM) before and after transcoronary ablation of septal hypertrophy (TASH).

METHODS AND RESULTS

Twenty-three of 39 consecutive patients with HOCM had serial two-dimensional (2D) echocardiograms available for speckle tracking analyses before and up to 36 months after TASH. Before TASH, overall LV myocardial longitudinal systolic 2D strain was decreased despite normal LV ejection fraction (EF). A significant reduction of LV mass and left ventricular outflow tract (LVOT) gradients occurred during long-term follow-up after TASH, but this was not accompanied by improvement of average LV longitudinal systolic strain. However, in the basal LV segments remote to the site of alcohol injection longitudinal systolic strain increased [baseline: -13.1 ± 5.4%; 1 month: -16.0 ± 5.5% (NS); 12 months: -16.5 ± 4.9% (P < 0.05 vs. baseline); 36 months: -17.4 ± 4.2% (P < 0.01 vs. baseline)]. In contrast, the alcohol-treated basal segments of the septum and adjacent myocardium showed unchanged strain over time.

CONCLUSION

Average LV longitudinal myocardial systolic function is depressed in HOCM despite normal LV EF. TASH-induced reduction of the LVOT obstruction does not improve average LV longitudinal systolic 2D strain. This is in contrast to global improvement of longitudinal systolic function after valve replacement in aortic valve stenosis. The discrepancy may be caused by the fact that HOCM is a primary myocardial disease.

Reduced global longitudinal strain in association to increased left ventricular mass in patients with aortic valve stenosis and normal ejection fraction: a hybrid study combining echocardiography and magnetic resonance imaging

Background

Increased muscle mass index of the left ventricle (LVMi) is an independent predictor for the development of symptoms in patients with asymptomatic aortic stenosis (AS). While the onset of clinical symptoms and left ventricular systolic dysfunction determines a poor prognosis, the standard echocardiographic evaluation of LV dysfunction, only based on measurements of the LV ejection fraction (EF), may be insufficient for an early assessment of imminent heart failure. Contrary, 2-dimensional speckle tracking (2DS) seems to be superior in detecting subtle changes in myocardial function. The aim of the study was to assess these LV function deteriorations with global longitudinal strain (GLS) analysis and the relations to LVMi in patients with AS and normal EF.

Methods

50 patients with moderate to severe AS and 31 controls were enrolled. All patients underwent echocardiography, including 2DS imaging. LVMi measures were performed with magnetic resonance imaging in 38 patients with AS and indexed for body surface area.

Results

The total group of patients with AST showed a GLS of -15,2 ± 3,6% while the control group reached -19,5 ± 2,7% (p < 0,001). By splitting the group with AS in normal, moderate and severe increased LVMi, the GLS was -17,0 ± 2,6%, -13,2 ± 3,8% and -12,4 ± 2,9%, respectively (p = 0,001), where LVMi and GLS showed a significant correlation (r = 0,6, p < 0,001).

Conclusions

In conclusion, increased LVMi is reflected in abnormalities of GLS and the proportion of GLS impairment depends on the extent of LV hypertrophy. Therefore, simultaneous measurement of LVMi and GLS might be useful to identify patients at high risk for transition into heart failure who would benefit from aortic valve replacement irrespectively of LV EF.

Prognostic effect of long-axis left ventricular dysfunction and B-type natriuretic peptide levels in asymptomatic aortic stenosis

In aortic stenosis (AS), the increased afterload results in progressive structural and functional changes that precede the development of symptoms. We hypothesized that the detection of abnormalities in left ventricular long-axis function could identify patients with asymptomatic AS at increased risk of events. We prospectively examined the outcome of 126 patients with asymptomatic AS who underwent a comprehensive echocardiographic examination, including tissue Doppler imaging. B-type natriuretic peptide (BNP) was measured in all patients. During a median follow-up period of 20.3 + or - 17.8 months, 6 patients died, 8 developed symptoms but did not undergo surgery, and 48 underwent aortic valve replacement. On multivariate Cox regression analysis, the parameters associated with the predefined outcome were gender (p = 0.048), left atrial area index (p = 0.011), systolic annular velocity (p = 0.016), E/Ea ratio (p = 0.024), late diastolic annular velocity (p = 0.023), and BNP (p = 0.012). Using receiver operating characteristics curve analysis, a left atrial area index of > or = 12.4 cm(2)/m(2), systolic annular velocity of < or = 4.5 cm/s, E/Ea ratio >13.8, late diastolic annular velocity of < or = 9 cm/s, and BNP of > or = 61 pg/ml were identified as the best cutoff values to predict events. In conclusion, in asymptomatic AS, tissue Doppler imaging and BNP measurements provide prognostic information beyond that from clinical and conventional echocardiographic parameters.

Left ventricular torsional dynamics in aortic stenosis: relationship between left ventricular untwisting and filling pressures. A two-dimensional speckle tracking study

AIMS

The contribution of left ventricular (LV) untwisting to LV suction and early-diastolic filling was previously demonstrated, but this was not yet tested in patients with aortic stenosis (AS). We sought to assess the relationship between LV untwisting and LV filling pressures in patients with severe AS and normal left ventricular ejection fraction (LVEF) using speckle tracking echocardiography.

METHODS AND RESULTS

Sixty-one consecutive patients (66 +/- 9 years) with severe AS, preserved LVEF (63 +/- 6%), and 40 normal subjects (47 +/- 12 years) were prospectively enrolled. A comprehensive echocardiographic examination was performed in all. LV rotation and twisting were assessed using speckle tracking echocardiography. Peak apical back rotation rate, peak LV untwisting rate, and time intervals from QRS onset (ECG) to each of them were measured. Brain natriuretic peptide (BNP) levels were determined in 30 patients. Patients with AS were older than normal subjects (P < 0.001). LV mass, LA volume, LV filling pressures as well as peak apical back rotation rate and time to peak apical back rotation rate were increased in patients (P < 0.05 for all). In patients with AS, both time to peak LV untwisting rate and time to peak apical back rotation rate were significantly related to E/E' ratio and to BNP levels (P < 0.04 for all).

CONCLUSION

In patients with severe AS and preserved LVEF, there is a significant relationship between LV untwisting and LV filling pressures, suggesting a role for impaired LV untwisting in the pathophysiology of diastolic dysfunction in this setting.

Current controversies in heart failure with a preserved ejection fraction

Heart failure with a preserved ejection fraction is a fascinating and multifaceted condition that has provoked enormous debate and a wealth of mechanistic studies. Controversies exist with regard to its nomenclature. If its nomenclature is questioned, one can be certain the pathogenesis is ill understood. If the pathogenesis is disputed, the diagnosis becomes difficult and inconsistent. These diagnostic challenges result in inappropriate recruitment to clinical trials. Therefore, the trials may be underpowered and difficult to interpret. This paper examines contemporary theories of heart failure with a preserved ejection fraction, clarifies the controversies and attempts to resolve the divergences of opinion.

Novel methods to assess heart valve disease

Optimal timing of surgery for heart valve disease relies on the accurate assessment of symptoms, lesion severity, cardiac function and the risks of disease progression. Recent studies suggest potential roles for new echocardiographic techniques, including tissue Doppler and strain imaging at rest or after exercise stress, cardiac magnetic resonance imaging and biomarkers such as B-type natriuretic peptide. These techniques may identify patients at higher risk of symptomatic deterioration or adverse clinical events, and improve the cost-effectiveness and reliability of follow-up.

Differential effects of afterload on left ventricular long- and short-axis function: insights from a clinical model of patients with aortic valve stenosis undergoing aortic valve replacement

BACKGROUND

The effects of left ventricular (LV) afterload on longitudinal versus circumferential ventricular mechanics are largely unknown. Our objective was to examine changes in LV deformation before and early after aortic valve replacement (AVR) in patients with severe aortic valve stenosis (AS).

METHODS

Paired echocardiographic studies before and early (7 +/- 3 days) after AVR were analyzed in 45 patients (age 67 +/- 12 years, 49% men) with severe AS and normal LV ejection fraction without segmental wall motion abnormalities. Longitudinal myocardial function was assessed from 3 apical views (average of 18 segments). Circumferential function was assessed at mid and apical levels (averaging 6 segments per view). Strain, strain rate (SR), and LV twist (relative rotation of the mid and apex) were measured using 2-dimensional strain software.

RESULTS

Early post-AVR, (1) LV size and LV ejection fraction did not change; (2) longitudinal systolic strain, which was lower than normal before AVR, increased (-12.8 +/- 1.7 to -15.9 +/- 2.2, P < .05), whereas mid-LV circumferential strain, which was higher than normal, decreased (-27.0 +/- 5.1 to -22.3 +/- 4.9, P < .05); (3) longitudinal early diastolic SR increased (0.6 +/- 0.1 to 0.7 +/- 0.2, P < .05), whereas mid-LV circumferential diastolic SR decreased (1.2 +/- 0.5 to 1.0 +/- 0.3, P < .05); and (4) LV twist increased (3.7 degrees +/- 2.1 degrees to 6.1 degrees +/- 2.9 degrees , P < .05).

CONCLUSIONS

Aortic valve stenosis causes differential changes in longitudinal and circumferential mechanics that partially normalize after AVR. These findings provide new insights into the mechanical adaptation of the LV to chronic afterload elevation and its response to unloading.

Is torsion a suitable echocardiographic parameter to detect acute changes in left ventricular afterload in children?

BACKGROUND

Congenital heart defects such as coarctation or valvular aortic stenosis are followed by changes in left ventricular myocardial deformation mechanics induced by pressure overload.

METHODS

Echocardiography was performed in 37 patients (aged 0-27 years, 15 female) with coarctation (27) or valvular aortic stenosis (10) before and after interventional catheterization and compared with 37 body surface area/age-matched healthy children. Deformation was calculated by 2-dimensional strain speckle tracking.

RESULTS

Stress gradients under provocation with orciprenaline in coarctation decreased from 51.8 +/- 20.0 mm Hg to 6.0 +/- 12.0 mm Hg (P < .0001), and resting gradients in aortic stenoses decreased from 57.5 +/- 18.8 mm Hg to 25.5 +/- 14.0 mm Hg (P < .0001) after intervention. Patients had an increased maximal torsion (tor(max): 16.7 +/- 6.7 deg vs 11.0 +/- 4.7 deg (controls; P < .0001), which decreased significantly after therapy (11.8 +/- 4.9 deg, P < .0001).

CONCLUSION

Compensatory elevation of left ventricular tor(max) in children with moderate left ventricular pressure load changes rapidly after successful interventional treatment. tor(max) may be a valuable tool to assess cardiac unloading or indicate the need for interventional treatment.

Strain and strain rate imaging by echocardiography - basic concepts and clinical applicability

Echocardiographic strain and strain-rate imaging (deformation imaging) is a new non-invasive method for assessment of myocardial function. Due to its ability to differentiate between active and passive movement of myocardial segments, to quantify intraventricular dyssynchrony and to evaluate components of myocardial function, such as longitudinal myocardial shortening, that are not visually assessable, it allows comprehensive assessment of myocardial function and the spectrum of potential clinical applications is very wide. The high sensitivity of both tissue Doppler imaging (TDI) derived and two dimensional (2D) speckle tracking derived myocardial deformation (strain and strain rate) data for the early detection of myocardial dysfunction recommend these new non-invasive diagnostic methods for extensive clinical use. In addition to early detection and quantification of myocardial dysfunction of different etiologies, assessment of myocardial viability, detection of acute allograft rejection and early detection of allograft vasculopathy after heart transplantation, strain and strain rate data are helpful for therapeutic decisions and also useful for follow-up evaluations of therapeutic results in cardiology and cardiac surgery. Strain and strain rate data also provide valuable prognostic information, especially prediction of future reverse remodelling after left ventricular restoration surgery or after cardiac resynchronization therapy and prediction of short and median-term outcome without transplantation or ventricular assist device implantation of patients referred for heart transplantation.The Review explains the fundamental concepts of deformation imaging, describes in a comparative manner the two major deformation imaging methods (TDI-derived and speckle tracking 2D-strain derived) and discusses the clinical applicability of these new echocardiographic tools, which recently have become a subject of great interest for clinicians.

Speckle tracking for left ventricle performance in young athletes with bicuspid aortic valve and mild aortic regurgitation

AIMS

Longitudinal peak systolic strain (LPSS) quantifies regional and global heart function. Few data are available on left ventricle (LV) performance in young athletes with bicuspid aortic valve (BAV), where a pattern of mild aortic insufficiency is relatively frequent, and the ejection fraction (EF) is often normal for a long time. We report the measurement of LV strain in young BAV athletes.

METHODS AND RESULTS

Three groups (20 athletes with BAV, 20 healthy athletes, and 20 sedentary healthy subjects, all aged 25 +/- 3 years) underwent standard echo examination to evaluate LPSS at the basal and medium-apical segments of the lateral wall (LW) and interventricular septum (IVS) of the LV. LPSS was within the normal range; however, in BAV athletes, the LPSS of the basal segments tended to be lower (S%IVS(basal), -17.7 +/- 2.7; S%LW(basal), -14.2 +/- 2.2; S%IVS(med-apic), -21 +/- 3.5; S%LW(med-apic), -18.8 +/- 4.2), producing a gradient from basal to apical regions. The EF was normal in all subjects.

CONCLUSION

Young trained BAV athletes have normal LV performance. Nevertheless, these athletes tend to have lower strain than healthy subjects in the LV basal segments. The clinical implications of this finding are uncertain and require further investigation.

Impact of impaired myocardial deformations on exercise tolerance and prognosis in patients with asymptomatic aortic stenosis

AIMS

As assessed by tissue Doppler velocities, longitudinal contraction is commonly altered at an earlier stage than radial contraction in patients with severe aortic stenosis (AS). However, its relationship to exercise tolerance or to prognosis has not been clearly established. By using two-dimensional (2D) echocardiographic strain, we sought to evaluate values of deformation components in the setting of severe AS and to correlate these values with exercise tolerance and with patients' outcome.

METHODS AND RESULTS

Sixty-five asymptomatic patients with severe AS (aortic valve area <1 cm(2)) were studied by echocardiography and exercise treadmill and were compared with controls. Conventional echographic parameters as well as longitudinal, radial, and circumferential deformations by 2D strain were measured at rest. During exercise treadmill, maximum tolerated workload, maximum heart rate, blood pressure, and EKG ST variations were recorded. Patients were then followed during 12 months. Compared with controls, despite similar ejection fractions, AS patients presented with a significantly lower global longitudinal strain (GLS) (-17.8 +/- 3.5 vs. -21.1 +/- 1.8%, P < 0.05) more pronounced in the basal segments (BLS) (-12.4 +/- 2.9 vs. -18.4 +/- 2.5%, P < 0.05). No difference was observed in terms of radial or circumferential strains. In a subgroup of AS patients with abnormal response to exercise, GLS and BLS were significantly lower (-14.7 +/- 5.1 vs. -19.3 +/- 4.0% and -10.7 +/- 2.5 vs. -14.4 +/- 2.1%, P < 0.05). With cut-offs of -18 and -13%, GLS and BLS were able to determine an inadequate exercise response with a sensitivity and specificity of 68 and 75% (AUC 0.77), and 77 and 83% (AUC 0.81), respectively. Finally, patients with a basal strain below -13% presented with more cardiac events in the follow-up.

CONCLUSION

In asymptomatic patients with severe AS, impaired longitudinal contraction assessed by 2D strain is associated with abnormal exercise response and with an increased risk of cardiac events during follow-up.