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).

Impact of transcatheter aortic valve implantation on mechanical dispersion

Objectives

The physiological determinants of left ventricular (LV) mechanical dispersion (MD) are not fully explored. We aimed to investigate the impact of afterload reduction and changes in ventricular conduction on LV MD after transcatheter aortic valve implantation (TAVI).

Methods

Patients with severe aortic stenosis (AS) were examined in a prospective, repeated measures observational cohort study before and after an uncomplicated transfemoral TAVI in a single tertiary centre. LV MD was assessed by speckle tracking echocardiography. Valvulo-arterial impedance (ZVA) was used as a measure of global afterload.

Results

We included 140 consecutive patients (83±8 years old, 49% women, logistic EuroSCORE 16±10) with severe AS (valve area 0.7±0.2 cm², mean transvalvular gradient 54±18 mm Hg) and a relatively preserved LV ejection fraction (52%±11%). After TAVI, we observed favourable changes in transvalvular gradients and ZVA in all patients. Compared with baseline, postprocedural MD was significantly lower in 108 patients with unchanged ventricular conduction (55±17 ms vs 51±17 ms, p=0.02) and higher in 28 patients with TAVI-induced left bundle branch block (51±13 ms vs 62±19 ms, p≤0.001). During 22±9 months observation, 22 patients died. Postprocedural MD was associated with mortality in a univariate Cox regression model (HR=1.24 (1.01-1.52), p<0.04, per 10 ms increase).

Conclusions

Isolated afterload reduction was associated with reduction of MD, while concomitant impairment of ventricular conduction resulted in a more pronounced MD after TAVI, indicating that loading conditions and conduction should be considered when evaluating MD. A pronounced postprocedural LV MD was associated with mortality.

Advanced echocardiographic imaging of the congenitally malformed heart

There have been significant advancements in the ability of echocardiography to provide both morphological and functional information in children with congenitally malformed hearts. This progress has come through the development of improved technology such as matrix array probes and software which allows for the off line analysis of images to a high standard. This article focuses on these developments and discusses some newer concepts in advanced echocardiography such is multi-planar reformatting [MPR] and tissue motion annular displacement [TMAD].

Our aim is to discuss important aspects related to the quality and reproducibility of data, to review the most recent published data regarding advanced echocardiography in the malformed heart and to guide the reader to appropriate text for overcoming the technical challenges of using these methods. Many of the technical aspects of image acquisition and post processing have been discussed in recent reviews by the authors and we would urge readers to study these texts to gain a greater understanding [1]. The quality of the two dimensional image is paramount in both strain analysis and three dimensional echocardiography. An awareness of how to improve image quality is vital to acquiring accurate and usable data.

Three dimensional echocardiography (3DE) is an attempt to visualise the dynamic morphology of the heart. Although published media is the basis for theoretical knowledge of how to practically acquire images, electronic media [eg.www.3dechocardiography.com] is the only way of visualising the advantages of this technology in real time.

It is important to be aware of the limitations of this technology and that much of the data gleaned from using these methods is at a research stage and not yet in regular clinical practice.

Increased regional deformation of the left ventricle in normal children with increased body mass index: implications for future cardiovascular health

The prevalence of obesity continues to increase in the developing world. The effects of obesity on the cardiovascular system include changes in systolic and diastolic function. More recently obesity has been linked with impairment of longitudinal myocardial deformation properties in children. We sought to determine the effect of increased body mass index (BMI) on cardiac deformation in a group of children taking part in the population-based Southampton Women's Survey to detect early cardiovascular changes associated with increasing BMI before established obesity. Sixty-eight children at a mean age of 9.4 years old underwent assessment of longitudinal myocardial deformation in the basal septal segment of the left ventricle (LV) using two-dimensional speckle tracking echocardiography. Parameters of afterload and preload, which may influence deformation, were determined from cardiac magnetic resonance imaging. BMI was determined from the child's height and weight at the time of echocardiogram. Greater pediatric BMI was associated with greater longitudinal myocardial deformation or strain in the basal septal segment of the LV (β = 1.6, p < 0.001); however, this was not related to contractility or strain rate in this part of the heart (β = 0.001, p = 0.92). The end-diastolic volume of the LV increased with increasing BMI (β = 3.93, p < 0.01). In young children, regional deformation in the LV increases with increasing BMI, whilst normal contractility is maintained. This effect may be explained by the increased preload of the LV associated with increased somatic growth. The long-term implications of this altered physiology need to be followed-up.

Left ventricular endocardial dysfunction in patients with preserved ejection fraction after receiving anthracycline

BACKGROUND

Anthracycline chemotherapy generates progressive dose-dependent left ventricular (LV) dysfunction associated with a poor prognosis. Early detection of minor LV myocardial dysfunction caused by the cardiotoxicity of anthracycline is thus important for predicting global LV dysfunction.

METHODS

Fifty patients with preserved ejection fraction (all ≥55%) after receiving anthracycline chemotherapy were recruited for this study. Two-dimensional speckle tracking was used to assess global radial and circumferential strains from mid-LV short-axis views and global longitudinal strain from the apical four- and two-chamber view as peak global strain curves. Three-dimensional (3D) radial, circumferential, and longitudinal myocardial function was quantified as a peak global strain curve using 3D speckle tracking from all 16 LV segments. 3D speckle tracking imaging was used to evaluate LV endocardial area change ratio (area strain) quantified as peak global area strain curve (3D-GAS) to determine LV endocardial function. Twenty age-, gender-, and EF-matched normal volunteers were studied for comparisons.

RESULTS

Only 3D-GAS and peak 3D global circumferential strains of the anthracycline group were significantly worse than those of the control group (-43.3 ± 3.1 vs. -45.8 ± 4.3% and -31.6 ± 3.5% vs. -34.4 ± 4.2%, respectively; P = 0.008, P = 0.004) even though global LV systolic and diastolic functions were similar. 3D-GAS correlated significantly with the cumulative doxorubicin dose (r = 0.316, P = 0.026). It was noteworthy that multivariate analysis showed only 3D-GAS (β = 0.323, P = 0.025) was independently associated with cumulative doxorubicin dose.

CONCLUSIONS

Three-dimensional speckle tracking area strain was found useful for early detection of minor LV endocardial dysfunction associated with the use of anthracycline, and may thus prove to be clinically useful for predicting global LV dysfunction.

Left atrial booster-pump function as a predictive parameter for new-onset postoperative atrial fibrillation in patients with severe aortic stenosis

Postoperative atrial fibrillation (POAF) is associated with increased risk of embolic events and heart failure, but its associated factors remains unknown. Left atrial (LA) subclinical mechanical dysfunction caused by the acute stress of surgery may be clinically manifested as POAF. The purpose of our study was therefore to test the hypothesis that preoperative LA subclinical myocardial dysfunction is a potential predictor of development of POAF in patients with aortic stenosis (AS). We studied 27 patients with severe AS undergoing aortic valve replacement (AVR) with left ventricular (LV) ejection fraction of 63 ± 11 %. All patients were in sinus rhythm and had no history of atrial fibrillation (AF). LA reservoir (SR-LAs), conduit (SR-LAe), and booster-pump (SR-LAa) functions were determined as the averaged global LA speckle-tracking longitudinal strain rates from apical four- and two-chamber views. POAF, defined as any episode of AF within 30-day after AVR, was observed in 15 patients (56 %). There were no differences in clinical characteristics, LA and LV volumes, and global LV function between patients with and without POAF. Multivariate logistic regression analysis identified SR-LAa as the only independent predictor of POAF. Furthermore, SR-LAa >0.79 s(-1) predicted POAF with 60 % sensitivity, 92 % specificity, and area under the curve of 0.828 (p < 0.0001). Of the 15 patients with POAF, one developed paroxysmal AF during long-term follow-up. In conclusions, SR-LAa helped to detect subtle LA booster-pump dysfunction and was associated with new-onset POAF in patients with severe AS. These findings may be useful for risk stratification and management of such patients.