Left atrial remodelling in patients undergoing transcatheter aortic valve implantation: a speckle-tracking prospective, longitudinal study

Early reverse remodeling by echocardiography after transcatheter aortic valve implantation

INTRODUCTION

Oslo University Hospital is a tertiary center conducting a significant number of transcatheter aortic valve implantation (TAVI) procedures per year. In this follow-up MediPace study, we aimed to investigate early echocardiographic changes in systolic and diastolic functions after TAVI in these patients.

METHODS

All patients enrolled in the previous study were contacted 3 months after TAVI for echocardiographic evaluation. Detailed echocardiography was performed 3.5 ± 1.6 months after TAVI, and compared with baseline evaluations.

RESULTS

A total of 101 patients were analyzed. Mean age was 80.1 ± 6.8 years and 40% of the patients were female. We observed a significant improvement in global longitudinal strain (GLS) (pre-TAVI -16.8 ± 4.1%, post-TAVI -17.8 ± 3.6%, p < .001), with no notable change in LVEF. More than half of the patients (52%) experienced a significant reverse remodeling with ≥10% decrease in left ventricular mass index (LVMi) following TAVI (pre-TAVI 123.6 ± 32.1 vs. 109.7 ± 28.9 g/m2 post-TAVI, p < .001). Pre-TAVI LVMi was a positive predictor, whereas history of HT was a negative predictor of LVMi reduction. There was no significant improvement in diastolic function following TAVI. Highest degree of paravalvular leakage was mild to moderate and was observed in only 2%.

CONCLUSIONS

A significant improvement in GLS and LVMi was found following TAVI. History of hypertension and baseline LVMi were predictors of LVMi change. There was no notable change in diastolic function, including left atrial strain.

Prognostic value of left atrial strain in aortic stenosis: A systematic review

PURPOSE

Aortic stenosis (AS) is a common valvular heart disease with high morbidity and mortality. Recently, the association between peak atrial longitudinal strain (PALS) and AS clinical outcomes has been identified. This systematic review evaluates the prognostic value of PALS for adverse events in AS.

METHODS

We performed a systematic literature review to identify clinical studies that evaluated Speckle-Tracking Echocardiography (STE)-derived PALS to predict adverse outcomes in patients with AS. We excluded studies that compared echocardiography to computed tomography and studies that focused on diseases other than AS.

RESULTS

We included 18 studies reporting on 2660 patients. Patients with symptomatic AS had decreased PALS when compared to patients with asymptomatic AS. Patients with AS who had adverse events had decreased PALS when compared to patients with AS with no events. Each unit increase of PALS was independently associated with decreased risk for the primary endpoint. PALS cut-off values were associated with increased risk for the primary endpoint.

CONCLUSION

This systematic review suggests PALS as an independent predictor for cardiovascular events in patients with AS and highlights the importance of evaluating LA mechanics for AS prognosis.

Cardiac power output is associated with adverse outcomes in patients with preserved ejection fraction after transcatheter aortic valve implantation

Aims

Cardiac power output (CPO) measures cardiac performance, and its prognostic significance in heart failure with preserved ejection fraction (EF) has been previously reported. However, the effectiveness of CPO in risk stratification of patients with valvular heart disease and post-operative valvular disease has not been reported. We aimed to determine the association between CPO and clinical outcomes in patients with preserved left ventricular (LV) EF after transcatheter aortic valve implantation (TAVI).

Methods and results

This retrospective observational study included 1047 consecutive patients with severe aortic stenosis after TAVI. All patients were followed up for all-cause mortality and hospitalization for HF. CPO was calculated as 0.222 × cardiac output × mean blood pressure (BP)/LV mass, where 0.222 was the conversion constant to W/100 g of the LV myocardium. CPO was assessed using transthoracic echocardiography at discharge after TAVI. Of the 1047 patients, 253 were excluded following the exclusion criteria, including those with low LVEF, and 794 patients (84.0 [80.0-88.0] years; 35.8% male) were included in this study. During a median follow-up period of 684 (237-1114) days, the composite endpoint occurred in 196 patients. A dose-dependent association was observed between the CPO levels and all-cause mortality. Patients in the lowest CPO tertile had significantly lower event-free survival rates (log-rank test, P = 0.043). Multivariate Cox regression analysis showed that CPO was independently associated with adverse outcomes (hazard ratio = 0.561, P = 0.020). CPO provided an incremental prognostic effect in the model based on clinical and echocardiographic markers (P = 0.034).

Conclusion

CPO is independently and incrementally associated with adverse outcomes in patients with preserved LVEF following TAVI.

The influence of transcatheter aortic valve replacement on left atrial mechanics: a systematic review and meta-analysis

Aims

The morphology and function of the left atrium (LA) are intimately tied to left ventricular loading conditions. Data pertaining to the effect of transcatheter aortic valve replacement (TAVR) on LA function and geometry are scarce. The aim of the study was to quantify associations between TAVR and LA remodelling by pooling available data from published observational studies.

Methods and results

A systematic review and meta-analysis were performed. Studies reporting serial LA speckle-tracking echocardiographic (STE) data, before and after TAVR, were included. Other outcome data included LA area and indexed volume (LAVi) and standard chamber measurements. Outcomes were stratified by timing of follow-up echocardiography: early (<6 months) or late (≥6 months). Twelve studies were included, comprising 1066 patients. The mean reduction in LAVi was 2.72 mL/m2 [95% confidence interval (CI) 1.37-4.06, P < 0.01]. LA reservoir function improved overall by a mean difference (MD) of 3.71% (95% CI 1.82-5.6, P < 0.01), although there was significant heterogeneity within the pooled studies (I 2 = 87.3%). Significant improvement in reservoir strain was seen in both early follow-up (MD 3.1%, P < 0.01) and late follow-up studies (MD 4.48%, P = 0.03), but heterogeneity remained high (I 2 = 65.23 and 94.4%, respectively). Six studies reported a change in LA contractile function, which recovered in the early follow-up studies (MD 2.26, P < 0.01), but not in the late group (MD 1.41, P = 0.05). Pooled improvement in LA booster function was 1.96% (95% CI 1.11-2.8, P < 0.01).

Conclusion

TAVR is associated with significant negative LA remodelling, and an improvement in LA mechanics, quantified by STE. The prognostic implications of these findings require further study.

Atrial electrical remodeling and function after transcatheter aortic valve replacement in patients with aortic stenosis

To examine reverse atrial electrical remodeling in patients with aortic stenosis (AS) after trans-catheter aortic valve replacement (TAVR). In 65 consecutive patients with severe AS (83 ± 4 years, 47 (72.3%) females), we analyzed ECG records for the P wave duration (PWD) in lead II and P-terminal force (PTFV1) in V1, and measured cardiac dimensions and function by echocardiography (ECHO) following TAVR. Biomarkers were measured to assess myocardial injury by TAVR. TAVR was successfully performed without major complications: the aortic valve area increased from 0.62 ± 0.14 cm2 to 1.52 ± 0.24cm2, and the trans-aortic pressure gradient decreased from 58.4 ± 15.9 mmHg to 15.0 ± 19.6 mmHg. PWD and PTFV increased immediately after TAVR and returned to the pre-TAVR levels on the next day. Then, the PWD declined toward 6 months after TAVR non-significantly in all patients, but significantly in 25 patients with baseline PWD ≥ 130 ms (P = 0.039). PTFV1 showed no long-term change. Improvement was observed in the ejection fraction, all thickness of the left ventricle and in the left atrial dimensions on ECHO. After recovery from transient aggravation by TAVR procedure, PWD reversed slowly, and the change was significant in those with baseline PWD ≥ 130 ms while change in PTFV1 was not significant at 6 months of follow-up. ECHO showed a reversal of remodeling in the left ventricle and in the left atrial dimension after TAVR.

Left atrial pump strain predicts long-term survival after transcatheter aortic valve implantation

BACKGROUND

This study aims at investigating left atrial (LA) deformation by left atrial reservoir (LARS) and pump strain (LAPS) and its implications for long-term survival in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI).

METHODS

Speckle tracking echocardiography was performed in 198 patients with severe AS undergoing TAVI. Association of strain parameters with cardiovascular mortality was determined.

RESULTS

Over a follow-up time of 5 years, 49 patients (24.7%) died. LAPS was more impaired in non-survivors than survivors (P = 0.010), whereas no difference was found for LARS (P = 0.114), LA ejection fraction (P = 0.241), and LA volume index (P = 0.292). Kaplan-Meier analyses yielded a reduced survival probability according to the optimal threshold for LAPS (P = 0.002). A more impaired LAPS was associated with increased mortality risk (HR 1.12 [95% CI 1.02-1.22]; P = 0.014) independent of LVEF, LAVI, age, and sex. Addition of LAPS improved multivariable echocardiographic (LVEF, LAVI) and clinical (age, sex) models with potential incremental value for mortality prediction (P = 0.013 and P = 0.031, respectively). In contrast, LARS and LAVI were not associated with mortality.

CONCLUSIONS

In patients undergoing aortic valve replacement for severe AS, LAPS was impaired in patients dying during long-term follow-up after TAVI, differentiated survivors from non-survivors, was independently associated with long-term mortality, and yielded potential incremental value for survival prediction after TAVI. LAPS seems useful for risk stratification in severe AS and timely valve replacement.

Atrial Cardiomyopathy in Valvular Heart Disease: From Molecular Biology to Clinical Perspectives

This review discusses the evolving topic of atrial cardiomyopathy concerning valvular heart disease. The pathogenesis of atrial cardiomyopathy involves multiple factors, such as valvular disease leading to atrial structural and functional remodeling due to pressure and volume overload. Atrial enlargement and dysfunction can trigger atrial tachyarrhythmia. The complex interaction between valvular disease and atrial cardiomyopathy creates a vicious cycle of aggravating atrial enlargement, dysfunction, and valvular disease severity. Furthermore, atrial remodeling and arrhythmia can predispose to atrial thrombus formation and stroke. The underlying pathomechanism of atrial myopathy involves molecular, cellular, and subcellular alterations resulting in chronic inflammation, atrial fibrosis, and electrophysiological changes. Atrial dysfunction has emerged as an essential determinant of outcomes in valvular disease and heart failure. Despite its predictive value, the detection of atrial fibrosis and dysfunction is challenging and is not included in the clinical routine. Transthoracic echocardiography and cardiac magnetic resonance imaging are the main diagnostic tools for atrial cardiomyopathy. Recently published data have revealed that both left atrial volumes and functional parameters are independent predictors of cardiovascular events in valvular disease. The integration of atrial function assessment in clinical practice might help in early cardiovascular risk estimation, promoting early therapeutic intervention in valvular disease.

Left Atrial Remodeling in Response to Aortic Valve Replacement: Pathophysiology and Myocardial Strain Analysis

Severe aortic stenosis (AS) is the most common valve disease in the elderly and is associated with poor prognosis if treated only medically. AS causes chronic pressure overload, concentric left ventricular (LV) hypertrophy, myocardial stiffness, and diastolic dysfunction. This adverse remodeling also affects the left atrium (LA), which dilates and develops myocardial fibrosis, with a reduction in intrinsic function and a consequent high risk of the development of atrial fibrillation. Speckle-tracking echocardiography is able to detect myocardial dysfunction before other conventional parameters, such as LV ejection fraction, and also predict clinical outcomes. This review aims at describing LV and LA remodeling in AS and before and after aortic valve replacement and the usefulness of myocardial strain analysis in this clinical setting.

Left Atrial Strain and the Risk of Atrial Arrhythmias From Extended Ambulatory Cardiac Monitoring: MESA

Background Abnormalities in left atrial (LA) function often occur before LA structural changes and clinically identified atrial fibrillation (AF). Little is known about the relationship between LA strain and the risk of subclinical atrial arrhythmias detected from extended ambulatory cardiac monitoring. Methods and Results A total of 1441 participants of MESA (Multi-Ethnic Study of Atherosclerosis) completed speckle-tracking echocardiography and cardiac monitoring during 2016 to 2018 (mean age, 73 years); participants in AF during echocardiography or during the entire cardiac monitoring period were excluded. Absolute values of LA reservoir, booster pump, and conduit strains were measured. We evaluated associations of LA strain with monitor-detected AF, premature atrial contractions, and supraventricular tachycardia. Primary analyses adjusted for demographic variables, blood pressure, diabetes, smoking, and clinical cardiovascular disease. Cardiac monitoring (median, 14 days) detected AF in 3%. Each SD (4.0%) lower (worse) LA booster pump strain was associated with 84% higher risk of monitor-detected AF (95% CI, 30%-162%), 39% higher premature atrial contraction frequency (95% CI, 27%-53%), and 19% higher supraventricular tachycardia frequency (95% CI, 10%-29%). Additional adjustment for NT-proBNP (N-terminal pro-B-type natriuretic peptide), LA volume index, tissue Doppler a' peak velocity, left ventricular ejection fraction, and global longitudinal strain had little impact on associations. Findings were similar for LA reservoir strain and null for LA conduit strain. Conclusions In a multiethnic community-based cohort, impaired LA strain was an important correlate of subclinical atrial arrhythmias, even after adjustment for conventional measures of LA structure and function.

Left atrial disease and left atrial reverse remodeling across different stages of heart failure development and progression: a new target for prevention and treatment

The left atrium is a dynamic chamber with peculiar characteristics. Stressors and disease mechanisms may deeply modify its structure and function, leading to left atrial remodelling and disease. Left atrial disease is a predictor of poor outcomes. It may be a consequence of left ventricular systolic and diastolic dysfunction and neurohormonal and inflammatory activation and/or actively contribute to the progression and clinical course of heart failure through multiple mechanisms such as left ventricular filling and development of atrial fibrillation and subsequent embolic events. There is growing evidence that therapy may improve left atrial function and reverse left atrial remodelling. Whether this translates into changes in patient's prognosis is still unknown.

In this review we report current data about changes in left atrial size and function across different stages of development and progression of heart failure. At each stage, drug therapies, lifestyle interventions and procedures have been associated with improvement in left atrial structure and function, namely a reduction in left atrial volume and/or an improvement in left atrial strain function, a process that can be defined as left atrial reverse remodelling and, in some cases, this has been associated with improvement in clinical outcomes. Further evidence is still needed mainly with respect of the possible role of left atrial reverse remodelling as an independent mechanism affecting the patient's clinical course and as regards better standardization of clinically meaningful changes in left atrial measurements. Summarizing current evidence, this review may be the basis for further studies.

The Predictive Value of Left Atrial Strain Following Transcatheter Aortic Valve Implantation on Anatomical and Functional Reverse Remodeling in a Multi-Modality Study

Introduction

Transcatheter aortic valve implantation (TAVI) can improve left ventricular (LV) mechanics and survival. Data on the predictive value of left atrial (LA) strain following TAVI are scarce. We aimed to evaluate the association of LA strain measured shortly post-TAVI with functional and anatomical reverse remodeling of the LA and LV, and its association with mortality.

Methods

We prospectively investigated 90 patients who underwent TAVI. Transthoracic echocardiography including strain analysis was performed shortly after TAVI and repeated 6 months later. CT angiography (CTA) was performed for pre-TAVI planning and 6 months post-TAVI. Speckle tracking echocardiography was used to determine LA peak reservoir strain (LASr) and LV global longitudinal strain (LV-GL), LA volume index (LAVi) was measured by TTE. LV mass index (LVMi) was calculated using CTA images. LA reverse remodeling was based on LASr and LAVi changes, whereas LV reverse remodeling was defined as an improvement in LV-GLS or a reduction of LVMi. The association of severely reduced LASr (&lt;20%) at baseline with changes (Δ) in LASr, LAVi, LV-GLS and LVMi were analyzed using linear regression, and Cox proportional hazard model for mortality.

Results

Mean LASr and LV-GLS were 17.7 ± 8.4 and −15.3 ± 3.4% at baseline and 20.2 ± 10.2 and −16.6 ± 4.0% at follow-up (p = 0.024 and p &lt; 0.001, respectively). Severely reduced LASr at baseline was associated with more pronounced ΔLASr (β = 5.24, p = 0.025) and LVMi reduction on follow-up (β = 5.78, p = 0.036), however, the majority of the patients had &lt;20% LASr on follow-up (44.4%). Also, ΔLASr was associated with ΔLV-GLS (adjusted β = 2.10, p &lt; 0.001). No significant difference in survival was found between patients with baseline severely reduced LASr (&lt;20%) and higher LASr (≥20%) (p = 0.054).

Conclusion

LV reverse remodeling based on LVMi was present even in patients with severely reduced LASr following TAVI, although extensive LA damage based on LA strain was demonstrated by its limited improvement over time.

Clinical Trial Registration

(ClinicalTrials.gov number: NCT02826200).

The Effect of TAVR on Left Ventricular and Left Atrial Mechanics in Patients with Aortic Stenosis

Background. Measures of adverse cardiac remodeling, left ventricular global longitudinal strain (LVGLS) and left atrial (LA) phasic function, are predictive of cardiac events in patients with severe aortic stenosis (AS). How these parameters of cardiac function change following TAVR requires further investigation. Methods. A number of 109 consecutive patients with symptomatic severe AS who were seen in the heart valve clinic between 2014 and 2019 for TAVR were included. All patients underwent echocardiographic assessment prior to and 30 days following TAVR, with LVGLS and LA phasic function evaluation using 2D speckle-tracking echocardiography. Heart failure hospitalization, and death were assessed at 12 months. Results. The mean age of the study cohort was 81 ± 7.3 years. Following TAVR, there was a significant reduction in NYHA class III/IV symptoms [89 (82%) vs. 12 (11%), p < 0.01], and median mean aortic valve gradient [44 mmHg (16) vs. 9 mmHg (7), p < 0.01]. There was no significant change in the median LVEF [62% (13) vs. 62% (6.0), p = 0.2]; however, the LVGLS significantly increased following TAVR [15 ± 3.5% vs. 18 ± 3.3%, p < 0.01]. The median LA reservoir, conduit and contractile function significantly improved following TAVR [22.0% (14.0) vs. 18.0% (14.0) p < 0.01, 8.9% (5.4) vs. 7.8% (4.8) p < 0.01, 12% (11.0) vs. 9.6% (11.0) p < 0.01, respectively]. The incidence of death or heart failure hospitalization at 12 months was low, and occurred in eight patients (7.3%). Conclusions. TAVR results in significant short-term reverse LV and LA remodeling, as shown by improvement in LV GLS and all three components of LA phasic function, despite no change in the LVEF. The findings indicate the possible utility of strain imaging for the assessment of global LV and LA function following TAVR.

Early reduction of left atrial function predicts adverse clinical outcomes in patients with severe aortic stenosis undergoing transcatheter aortic valve replacement

Aims

To investigate the changes in left atrial strain (LAS) after correction of severe aortic stenosis (AS) with transcatheter aortic valve replacement (TAVR) and assess its prognostic impact.

Methods and results

One hundred consecutive patients with severe symptomatic AS who underwent TAVR at the Magna Graecia University of Catanzaro underwent echocardiographic examination including assessment of LAS before and after TAVR. Independent investigators collected outcome data and information. The primary study outcome was the difference in ΔLAS (postTAVR–preTAVR) between patients those met the main clinical endpoint (a composite of cardiovascular mortality and heart failure hospitalisation) and those not meeting the endpoint.

During a median follow-up of 31 months, 35 patients (35%) met the combined clinical endpoint. The difference between LAS post-TAVR and LAS pre-TAVR (ΔLAS) was significantly larger in patients who met the combined endpoint (HR=0.76 (0.67–0.86); p<0.001). Multivariate logistic regression analysis including ΔLAS, EuroSCORE II and left ventricular ejection fraction showed that ΔLAS (HR=0.80, p<0.001) was the only independent predictor of the combined clinical endpoint. Finally, a Kaplan-Maier analysis showed that patients with a ΔLAS above its median value had a significantly better event-free survival compared with those below the median (p<0.001).

Conclusions

A lower reduction in ΔLAS after TAVR was an independent predictor of the primary composite outcome of cardiovascular death and hospitalisation for heart failure.

Multi-modality assessment and role of left atrial function as an imaging biomarker in cardiovascular disease

The left atrium (LA) plays a vital role in maintaining normal cardiac function. LA volume and function have been utilised as important imaging biomarkers, with their prognostic value demonstrated in multiple cardiac conditions. More recently, there has been a sharp increase in the number of publications utilising LA strain by echocardiography and cardiac magnetic resonance (CMR) imaging. However, little is known about its prognostic value or reproducibility as a technique. In this review, we aim to highlight the conventional and novel imaging techniques available for LA assessment, using echocardiography and CMR, their role as an imaging biomarker in cardiovascular disease, the reproducibility of the techniques and the current limitations to their clinical application. We identify a need for further standardisation of techniques, with establishment of ‘normal’ cut-offs before routine clinical application can be made.

The Prognostic Value of Left Atrial Global Longitudinal Strain and Left Atrial Phasic Volumes in Patients Undergoing Transcatheter Valve Implantation for Severe Aortic Stenosis

INTRODUCTION

The changes and the prognostic implications of left atrial (LA) volumes (LAV), LA function, and vascular load in patients undergoing transcatheter aortic valve implantation (TAVI) for severe aortic stenosis (AS) are less known.

METHODS

We enrolled 150 symptomatic patients (mean age 82 ± 8 years, 58% female, and pre-TAVI aortic valve area 0.40 ± 0.19 cm/m2) with severe AS who underwent 2D transthoracic echocardiography and 2D speckle tracking echocardiography at average 21 ± 35 days before and 171 ± 217 days after TAVI. The end point was a composite of new onset of atrial fibrillation, hospitalization for heart failure and all-cause death (major adverse cardiac events [MACE]).

RESULTS

After TAVI, indexed maximal LA volume and minimum volume of the LA decreased by 2.1 ± 10 mL/m2 and 1.6 ± 7 mL/m2 (p = 0.032 and p = 0.011, respectively), LA function index increased by 6.8 ± 11 units (p < 0.001), and LA stiffness decreased by 0.38 ± 2.0 (p = 0.05). No other changes in the LA phasic volumes, emptying fractions, and vascular load were noted. Post-TAVI, both left atrial and ventricular global peak longitudinal strain improved by about 6% (p = 0.01 and 0.02, respectively). MACE was reached by 37 (25%) patients after a median follow-up period of 172 days (interquartile range, 20-727). In multivariable models, MACE was associated with both pre- and post-TAVI LA global peak longitudinal strain (hazard ratio [HR] 0.75, CI 0.59-0.97; and HR 0.77, CI 0.60-1.00, per 5 percentage point units, respectively), pre-TAVI LV global endocardial longitudinal strain (HR 1.37, CI 1.02-1.83 per 5 percentage point units), and with most of the LA phasic volumes.

CONCLUSION

Within 6 months after TAVI, there is reverse LA remodeling and an improvement in LA reservoir function. Pre- and post-TAVI indices of LA function and volume remain independently associated with MACE. Larger studies enrolling a greater diversity of patients may provide sufficient evidence for the utilization of these imaging biomarkers in clinical practice.

Incremental prognostic role of left atrial reservoir strain in asymptomatic patients with moderate aortic stenosis

Left atrial (LA) mechanics assessed by two-dimensional speckle tracking echocardiography (2D-STE) have not been extensively studied and clearly characterized in patients with moderate aortic stenosis (AS). Accordingly, we aimed to evaluate the usefulness of LA reservoir strain for risk stratification of asymptomatic patients with moderate AS. This retrospective study included all consecutive asymptomatic patients with moderate AS who underwent transthoracic echocardiography implemented with 2D-STE analysis of LA myocardial strain and strain rate indices at our Institution, between February 2011 and September 2019. During the follow-up period, we evaluated the occurrence of any of the following: (1) CV hospitalization; (2) The recourse to AS surgery; (3) Cardiac death or sudden death. A total of 186 patients (mean age 71.9 ± 12.7 years, 61.8% men) were included in the present study. During a mean follow-up of 2.3 ± 1.9 years, no patients died and 63 adverse CV events were recorded: 48 patients were hospitalized because of heart failure (28 patients), acute coronary syndrome (10 patients), arrhythmias (10 patients) and 15 patients underwent AS surgery. At the multivariate Cox regression analysis, type 2 diabetes mellitus (OR 1.87, 95%CI 1.05-3.34, p = 0.03), NT-proBNP (OR average 1.14, 95%CI 1.02-1.27, p = 0.02), average E/e' ratio (OR 1.07, 95%CI 1.01-1.15, p = 0.04) and most of all left atrial positive global strain (LA-GSA+) (OR 0.85, 95%CI 0.81-0.90, p < 0.0001) were independently associated with the outcome. LA-GSA+ (optimal cut-off ≤ 19%, AUC = 0.94, 87% sensitivity, 99% specificity, positive predictive value 99%, negative predictive value 88%) showed the highest diagnostic performance. An impaired LA reservoir strain can contribute to identify a subset of asymptomatic patients with moderate AS at higher risk, who may benefit from closer echocardiographic follow-up and/or early surgery.

Usefulness of Longitudinal Strain to Assess Remodeling of Right and Left Cardiac Chambers Following Transcatheter Aortic Valve Implantation

Remodeling after transcatheter aortic valve implantation (TAVI) has been well characterized for the left ventricle (LV) but not for the other cardiac chambers. We aimed to describe conventional indices of cardiac remodeling and novel longitudinal strain (LS) in all 4 cardiac chambers post-TAVI and to explore gender remodeling disparities. Consecutive patients with significant aortic stenosis who underwent TAVI were included if echocardiograms in sinus rhythm before and 1-year postprocedure were available. Speckle tracking analysis was performed retrospectively to evaluate size and function of the 4 cardiac chambers. Baseline and 1-year data were compared. From a total of 612 patients who underwent TAVI, 213 were included in this study (82 ± 9 years old, 42% men). Although no significant size or function changes were seen for right cardiac chambers at follow-up, significant improvements were seen for ejection fraction (EF) and LS in both the LV and left atrium (LA) (p < 0.05 for both). The absolute percentage of LV and LA function improvement was higher for LS than for EF (p < 0.05). Women had smaller LV and right ventricular (RV) size, whereas parameters of LV and RV function were higher. All 1-year remodeling parameters were similar for men and women. Conventional LV remodeling parameters (LV mass) failed to improve 1 year after TAVI. However, novel strain-derived parameters of size and function showed remodeling of left chambers but not of RV or right atrium. The degree of LV and LA remodeling by LS is almost twice that of EF. Remodeling was similar for both genders.

The role of the left atrial function in the surgical management of aortic and mitral valve disease

The right management of both mitral and aortic disease can be challenging, especially in asymptomatic patients. The current guidelines recommend valve repair or replacement when symptoms arise or when there is an evident left ventricular dysfunction. However, deciding the optimal surgical timing can be very difficult, since the line between the absence of symptoms and being minimally symptomatic, especially in the elderly, is blurred. Another relevant issue regards the second surgical criterion: operating on a patient with a reduced left ventricular ejection fraction or with a dilated left ventricle might jeopardize the possibility of a fully reverse remodeling of the heart after surgery. In this scenario, the left atrium might play an important role. In particular, left atrial deformation might be a very useful tool to detect early ultrastructural alterations, and help or support guiding a patient-tailored treatment at an early stage, optimizing the outcome in the long term.

Left atrial remodeling postseptal myectomy for severe obstructive hypertrophic cardiomyopathy: Analysis by two-dimensional speckle-tracking echocardiography

BACKGROUND

Septal myectomy relieves left ventricular outflow obstruction (LVOTO) and is associated with excellent long-term outcomes. LVOTO is associated with diastolic dysfunction and increased left atrial (LA) size. We sought to investigate the changes in LA volumes and function postmyectomy and the association between these changes with clinical outcomes postmyectomy.

METHODS

Sixty-six hypertrophic cardiomyopathy patients undergoing myectomy were retrospectively studied. Preprocedural and 6- to 18-month postmyectomy follow-up transthoracic echocardiographic images were obtained. LA volumes and strain were assessed by two-dimensional speckle-tracking echocardiography.

RESULTS

Left atrial volumes, that is, indexed maximal, minimal, and pre-A volumes reduced postmyectomy, yet remained increased compared to controls (105.6 ± 34.5 mL vs 84.9 ± 26.7 mL, 45.2 ± 25.7 mL vs 35.4 ± 22.6 mL, 70.1 ± 31.4 mL vs 35.4 ± 22.6 mL, respectively, P < 0.05). The total emptying index did not improve postmyectomy and remained lower than controls (58.6 ± 12.4 vs 59.9 ± 12.8, P = NS) whereas atrial contraction improved, yet did not normalize (active emptying index 36.1 ± 14.9 vs 41.1 ± 16.2, P < 0.05). The conduit volume remained reduced postmyectomy (18.6 ± 13.3 mL vs 16.6 ± 15.1 mL, P = NS). LA strain also did not improve postmyectomy (26.8 ± 7.3 vs 28.5 ± 8.8, P = NS). A multivariable logistic regression identified preprocedural E/e' ratio and indexed maximal LA volume, as independent predictors for LA volume reduction ≥20% postmyectomy. During a mean follow-up of 4.9 ± 2.3 years postmyectomy, 24.2% of the patients developed atrial fibrillation and <5% of patients were severely symptomatic. We found no associations between LA volumes/function and atrial fibrillation or symptoms postmyectomy.

CONCLUSION

Postmyectomy LA volumes decreased, and the contractile function improved. There was no association between LA volumes/function and clinical outcomes postmyectomy. Notably, the LA remained enlarged (though to a lesser degree) with reduced strain and emptying fraction, suggesting possible atrial myopathy.

Left atrial strain and distensibility in relation to left ventricular dysfunction and prognosis in aortic stenosis

OBJECTIVE

To test the relationship between left atrial (LA) distensibility (LAD), LA strain (LAS), and left ventricular (LV) dysfunction and prognosis in aortic stenosis (AS).

METHODS

Transthoracic Doppler echocardiography was performed prospectively in 102 consecutive patients with AS (77 with severe, 25 with moderate, mean age 77 years). LA volume was calculated by the area-length method in apical four- and two-chamber views, immediately before mitral valve opening (Vol_max ) and at mitral valve closure (Vol_min ). LAD was defined as (Vol_max   - Vol_min ) × 100%/Vol_min . LAS (mean of maximal strain from the 4-2 chamber views) was conducted using a dedicated software package. The endpoint was hospitalization for heart failure and death from any cause.

RESULTS

Left atrial strain, LAD, and LA vol/m² were significantly correlated with LV diastolic parameters, and PASP (all, P < 0.05). However, LAD and LAS but not LA vol/m² were significantly correlated with Charlson score, LV global longitudinal strain, and to transaortic mean gradient (all, P < 0.05). At a median follow-up of 25 months, 53 patients had an event. LAS, LAD, LA vol/m², and Charlson index were associated with events (all, P < 0.05). In multivariate analysis, LAD, LAS, and Charlson index (all, P < 0.01) remained independently associated with events. Using a ROC curve analysis, LAD ≤ 69% and LAS ≤ 17% were the best cutoffs associated with an event.

CONCLUSION

In patients with moderate to severe AS, LAD and LAS are associated with LV dysfunction, AS severity, and are independently linked to events.

Pulmonary Hypertension in Aortic and Mitral Valve Disease

In patients with aortic and/or mitral valve disease the presence of pulmonary hypertension (PH) indicates a decompensated state of the disease with left ventricular and left atrial dysfunction and exhausted compensatory mechanism, i.e., a state of heart failure. Pulmonary hypertension in this context is the consequence of the backwards transmission of elevated left atrial pressure. In this form of PH, pulmonary vascular resistance is initially normal (isolated post-capillary PH). Depending on the extent and chronicity of left atrial pressure elevation additional pulmonary vascular remodeling may occur (combined pre- and post-capillary PH). Mechanical interventions for the correction of valve disease often but not always reduce pulmonary pressures. However, the reduction in pulmonary pressures is often modest, and persistent PH in these patients is common and a marker of poor prognosis. In the present review we discuss the pathophysiology and clinical impact of PH in patients with aortic and mitral valve disease, the comprehensive non-invasive and invasive diagnostic approach required to define treatment of PH, and recent insights from mechanistic studies, registries and randomized studies, and we provide an outlook regarding gaps in evidence, future clinical challenges, and research opportunities in this setting.

Relation Between Left Ventricular Outflow Tract Calcium and Mortality Following Transcatheter Aortic Valve Implantation

Left ventricular outflow tract (LVOT) calcium is known to be associated with adverse procedural outcomes after transcatheter aortic valve implantation (TAVI), yet its effect on midterm outcomes has not been previously investigated. The aim of this study was to determine the influence of LVOT calcium on 2-year mortality after TAVI. A total of 537 consecutive patients underwent TAVI and 2 groups were established, stratified based on the severity of the LVOT calcium. The primary outcome was 2-year overall survival rate. The ≥moderate LVOT calcium group included 107 patients (19.9%) and the remaining 430 patients (80.1%) were included in the ≤mild LVOT calcium group. After a median follow-up of 717 days (interquartile range 484 to 828), the Kaplan-Meier analysis revealed that the 2-year overall survival probability was significantly lower in the ≥moderate LVOT calcium group than in the ≤mild LVOT calcium group (log-rank p = 0.001). On a Cox hazard model, ≥moderate LVOT calcium was associated with increased all-cause mortality after TAVI (hazard ratio 1.74, p = 0.009). In the subgroup analysis, based on valve designs, SAPIEN 3-TAVI done in the setting of ≥moderate LVOT calcium had a relatively similar survival probability as those of ≤mild LVOT calcium (log-rank p = 0.18), which is in contrast with older generation valves (log-rank p = 0.001). In conclusion, patients with ≥moderate LVOT calcium were shown to have a lower survival probability in the midterm follow-up after TAVI, compared with those with ≤mild LVOT calcium. Patients with high-grade LVOT calcium should be monitored with longer-term follow-ups after TAVI.

Effect of transcatheter aortic valve replacement on P-wave duration, P-wave dispersion and left atrial size

Background

P-wave dispersion (PWD), a measure of heterogeneity of atrial refractoriness, is defined as the difference between the maximum and minimum P-wave duration. In patients with severe aortic stenosis (AS), P-wave duration and PWD were shown to be increased, indicating atrial electrical remodeling. However, the effect of transcatheter aortic valve replacement (TAVR) on P-wave morphology has not been established yet. The aim of this study is to assess the short and long-term effects of TAVR with two types of bioprosthetic valves on P-wave duration and PWD in association with left atrial (LA) size.

Methods

Fifty-two (36 female) eligible patients in sinus rhythm who underwent transfemoral TAVR between June 01, 2012 and July 31, 2014 with either a Medtronic CoreValve (MCV) (n = 32) or an Edwards SAPIEN XT Valve (n = 20) were enrolled. Standard 12-lead electrocardiogram and echocardiographic evaluations were performed pre-procedurally, post-TAVR day one and 6 months post-TAVR. P-wave duration and PWD were measured and correlation analyses with echocardiographic variables were performed.

Results

P-wave duration and PWD were significantly decreased on post-TAVR day one (P < 0.05). They continued to decrease during the six month follow-up period, but were not significantly different from short-term values (P > 0.05). The decrease of LA diameter was found significant at the sixth-months of follow-up (P < 0.05). These changes were independent from the types of bioprosthetic valves implanted (P > 0.05). A positive correlation was detected between minimum P-wave duration and maximum aortic valve gradients at post-TAVR day one (r = 0.297, P = 0.032).

Conclusions

P-wave duration and PWD were significantly reduced early after TAVR indicating early reverse atrial electrical remodeling. Moreover, structural reverse remodeling of atrium was detected at the 6-months of follow-up. The effects of two types of bioprosthetic valves on atrial remodeling were similar.

Assessment of left atrial function by MRI myocardial feature tracking

BACKGROUND

Left atrium (LA) volumes and function are predictors of cardiovascular events. Because LA function cannot be assessed from cardiovascular magnetic resonance imaging (MRI) using the well-established left ventricular tagging techniques, we hypothesized that adequate feature tracking (FT) applied to conventional cine MRI data could characterize LA function accurately.

METHODS

We studied 10 young (28 ± 7 years) and 10 elderly (64 ± 6 years) healthy subjects, as well as 20 patients with moderate to severe aortic valve stenosis (AVS; 73 ± 15 years, effective aortic valve area: 0.67 ± 0.36 cm(2) ). MRI cine two-, three-, and four-chamber views were analyzed using a newly proposed FT method based on spatial correlation and endocardial detection resulting in: regional and global longitudinal strain and strain rate, radial motion fraction and relative velocity for the three LA motion phases including reservoir, conduit, and LA contraction.

RESULTS

FT reliability was indicated by a good overlap between tracking results and manual LA endocardial borders, the low error for comparison against theoretical strains introduced in a synthetic phantom and the good inter-observer reproducibility (coefficient of variation < 15%). While all LA functional parameters were significantly impaired in AVS patients (p < 0.04), subclinical age-related variations induced a decreasing trend on all LA parameters but were significant only for radial conduit function parameters (p < 0.03). Finally, LA functional parameters characterized LA alteration in AVS with higher sensitivity than conventional LA volumetric parameters.

CONCLUSIONS

Left atrial FT is feasible on MRI cine images and its addition to conventional analysis tools might enhance the diagnosis value of MRI in many heart diseases.