Decision Making in Asymptomatic Aortic Regurgitation in the Era of Guidelines

Outcomes of Watchful Waiting Strategy and Predictors of Postoperative Prognosis in Asymptomatic or Equivocally Symptomatic Chronic Severe Aortic Regurgitation With Preserved Left Ventricular Function

BACKGROUND

The optimal surgical timing for asymptomatic or equivocally symptomatic chronic severe aortic regurgitation with preserved left ventricular ejection fraction remains controversial.

METHODS AND RESULTS

Two hundred ten consecutive patients (median age 65 years) with asymptomatic or equivocally symptomatic chronic severe aortic regurgitation and left ventricular ejection fraction ≥50% were registered. First, the treatment plans (aortic valve replacement or watchful waiting) after initial diagnosis were investigated. Then, 2 studies were set: Study A (n=144) investigated the prognosis of patients who were managed under the watchful waiting strategy after initial diagnosis; Study B (n=99) investigated the postoperative prognosis in patients who underwent aortic valve replacement at initial diagnosis or after watchful waiting. The primary outcomes were all-cause death in Study A and postoperative cardiovascular events in Study B. In Study A, 3 died of noncardiovascular causes during a median follow-up of 3.2 years. In Kaplan-Meier analysis, the survival curve was similar to that of an age-sex-matched general population in Japan. In Study B, 9 experienced the primary outcome during a median follow-up of 5.0 years. In Cox regression analysis, preoperative left ventricular end-systolic diameter enlargement (hazard ratio, 1.11; P=0.048) and left ventricular end-systolic diameter >45 mm (hazard ratio, 12.75; P=0.02) were significantly associated with poor postoperative prognosis. In Kaplan-Meier analysis, left ventricular end-systolic diameter >45 mm predicted a higher risk of the primary outcome (P <0.01).

CONCLUSIONS

Watchful waiting was achieved safely in asymptomatic or equivocally symptomatic chronic severe aortic regurgitation with preserved left ventricular ejection fraction. Preoperative left ventricular end-systolic diameter >45 mm predicted a poor postoperative outcome and may be an optimal cut-off value for surgical indication.

The Role of Global Longitudinal Strain in the Follow-Up of Asymptomatic Patients with Chronic Primary Mitral Regurgitation

Background/Objectives: In patients with chronic primary mitral regurgitation (MR), postoperative persistent left ventricular (LV) dysfunction underlines the lack of a sensitive parameter that can identify subclinical LV dysfunction and optimize the timing of intervention. Left ventricular global longitudinal strain (LV-GLS) is a measure of the longitudinal left ventricular systolic function, with prognostic significance. Its role in the follow-up of asymptomatic patients with MR is, however, poorly defined. The aim of this study was to assess the relative changes in LV-GLS in a cohort of MR patients and to correlate these changes with the need for intervention during a follow-up period. Methods: We conducted a prospective study on a cohort of 218 patients, divided into three subgroups according to MR severity (mild, moderate, severe). LV-GLS was measured at baseline and every six months during a median follow-up period of 30 months. The composite endpoint was the occurrence of heart failure symptoms, hospitalization for heart failure, LVEF < 60%, LVEDD > 45 mm, new onset atrial fibrillation, or cardiovascular death. Results: Patients with moderate and severe MR had a significantly lower GLS at baseline than those with mild MR (19.5% and 19.1% versus 22.3%, p < 0.01) despite a normal LVEF in all subgroups. The relative decrease in LV-GLS occurred earlier (at 12 months vs. 24 months) and was more evident in patients with moderate and severe MR (13.6% and 14.5%, respectively) versus patients with mild MR (6.72%). The baseline LV-GLS being under 18% and a relative decrease of over 10% in GLS were independent predictors of a composite outcome (HR = 1.59, CI 95% 1.17-2.86; HR = 1.74, CI 95% 1.2-2.91, p < 0.01). Conclusions: LV-GLS is a valuable monitoring tool for asymptomatic MR patients, a relative decrease > 10% in GLS may be predictive for the need for valve intervention.

Advanced myocardial characterization and function with cardiac CT

Non-invasive imaging with characterization and quantification of the myocardium with computed tomography (CT) became feasible owing to recent technical developments in CT technology. Cardiac CT can serve as an alternative modality when cardiac magnetic resonance imaging and/or echocardiography are contraindicated, not feasible, inconclusive, or non-diagnostic. This review summarizes the current and potential future role of cardiac CT for myocardial characterization including a summary of late enhancement techniques, extracellular volume quantification, and strain analysis. In addition, this review highlights potential fields for research about myocardial characterization with CT to possibly include it in clinical routine in the future.

The right ventricular dysfunction and ventricular interdependence in patients with T2DM and aortic regurgitation: an assessment using CMR feature tracking

BACKGROUND

Patients with concomitant type 2 diabetes mellitus (T2DM) and aortic regurgitation (AR) can present with right ventricular (RV) dysfunction. The current study aimed to evaluate the impact of AR on RV impairment and the importance of ventricular interdependence using cardiac magnetic resonance feature tracking (CMR‑FT) in patients with T2DM.

METHODS

This study included 229 patients with T2DM (AR-), 88 patients with T2DM (AR+), and 122 healthy controls. The biventricular global radial strain (GRS), global circumferential strain (GCS), and global longitudinal peak strain (GLS) were calculated with CMR‑FT and compared among the healthy control, T2DM (AR-), and T2DM (AR+) groups. The RV regional strains at the basal, mid, and apical cavities between the T2DM (AR+) group and subgroups with different AR degrees were compared. Backward stepwise multivariate linear regression analyses were performed to determine the effects of AR and left ventricular (LV) strains on RV strains.

RESULTS

The RV GLS, LV GRS, LV GCS, LV GLS, interventricular septal (IVS) GRS and IVS GCS were decreased gradually from the controls through the T2DM (AR-) group to the T2DM (AR+) group. The IVS GLS of the T2DM (AR-) and T2DM (AR+) groups was lower than that of the control group. AR was independently associated with LV GRS, LV GCS, LV GLS, RV GCS, and RV GLS. If AR and LV GLSs were included in the regression analyses, AR and LV GLS were independently associated with RV GLS.

CONCLUSION

AR can exacerbate RV dysfunction in patients with T2DM, which may be associated with the superimposed strain injury of the left ventricle and interventricular septum. The RV longitudinal and circumferential strains are important indicators of cardiac injury in T2DM and AR. The unfavorable LV-RV interdependence supports that while focusing on improving LV function, RV dysfunction should be monitored and treated in order to slow the progression of the disease and the onset of adverse outcomes.

Aortic Regurgitation: From Valvular to Myocardial Dysfunction

Chronic aortic regurgitation (AR) leads to volume overload in the left ventricle (LV), which is well tolerated for years. In this condition, the LV usually dilates with minimal reduction in the ejection fraction (EF), even in the absence of symptoms. Echocardiography is the primary imaging test used to quantify AR. However, no single assessment of Doppler measures is accurate and precise in individual patients; therefore, the integration of multiple parameters is necessary. Recent guidelines recommend surgical treatment for severe AR in patients who are symptomatic or have an LVEF < 55% and an end-systolic diameter > 50 mm. Nevertheless, advances in imaging technology have improved the quantification of AR and the assessment of LV subclinical dysfunction. It is widely recognized that patients who undergo aortic valve replacement/repair (AVR) due to symptoms or a low LVEF experience worse outcomes than those undergoing AVR for non-Class I indications. In fact, subclinical irreversible myocardial damage may occur in clinically well-compensated and closely monitored patients while awaiting formal surgical indications. This condition could be prevented by the use of multimodal imaging parameters, in particular longitudinal LV strain and magnetic resonance imaging. In addition, better cut-off values for mortality predictors should be established. This review aims to identify simple models that integrate several echocardiographic and cardiac magnetic resonance-derived parameters to predict the optimal timing of surgical treatment in asymptomatic patients with chronic severe AR.

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

INTRODUCTION

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

Stress echocardiography in valvular heart disease

Valvular heart disease (VHD) has been a significant health problem, particularly in developed countries, in relation to the aging population. Recent developments in the management of VHD require a more accurate assessment of disease severity to determine the need for transcatheter interventions or open heart surgery. Stress echocardiography is a crucial imaging modality for identifying the underlying pathology of VHD. Optimal administration of exercise or intravenous drugs may reveal hemodynamic abnormalities under stress without posing an invasive risk. Therefore, the implementation of stress echocardiography is recommended for determining interventional indications and risk stratification in mitral regurgitation and aortic stenosis. In addition, recent evidence has accumulated regarding the usefulness of stress echocardiography in various conditions including mitral stenosis, aortic regurgitation, and post-interventional VHD. Here, we summarize the current evidence and future perspectives on stress echocardiography in VHD.

Contemporary Evaluation and Clinical Treatment Options for Aortic Regurgitation

Aortic regurgitation (AR) is the third most frequent form of valvular disease and has increasing prevalence with age. This will be of increasing clinical importance with the advancing age of populations around the globe. An understanding of the various etiologies and mechanisms leading to AR requires a detailed understanding of the structure of the aortic valve and aortic root. While acute and chronic AR may share a similar etiology, their hemodynamic impact on the left ventricle (LV) and management are very different. Recent studies suggest current guideline recommendations for chronic disease may result in late intervention and suboptimal outcomes. Accurate quantitation of ventricular size and function, as well as grading of the severity of regurgitation, requires a multiparametric and multimodality imaging approach with an understanding of the strengths and weaknesses of each metric. Echocardiography remains the primary imaging modality for diagnosis with supplemental information provided by computed tomography (CT) and cardiac magnetic resonance imaging (CMR). Emerging transcatheter therapies may allow the treatment of patients at high risk for surgery, although novel methods to assess AR severity and its impact on LV size and function may improve the timing and outcomes of surgical intervention.

The basic heart anatomy and physiology from the cardiologist's perspective: Toward a better understanding of left ventricular mechanics, systolic, and diastolic function

A comprehensive understanding of the cardiac structure-function relationship is essential for proper clinical cardiac imaging. This review summarizes the basic heart anatomy and physiology from the perspective of a heart imager focused on myocardial mechanics. The main issues analyzed are the left ventricular (LV) architecture, the LV myocardial deformation through the cardiac cycle, the LV diastolic function basic parameters and the basic parameters of the LV deformation used in clinical practice for the LV function assessment.

Highlighting the role of global longitudinal strain assessment in valvular heart disease

Background

Echocardiography has been the choice for imaging modality for valvular heart disease. It is less invasive, widely available, and allows valvular structure visualization. Echocardiographic assessment often also determines the management. Left ventricular ejection fraction is the most commonly used indicator during echocardiography assessment. It shows signs of left ventricular dysfunction in patients with valve disease. However, most of the time, the ongoing process of cardiac damage may already occur even with preserved cardiac function; further deteriorated ejection fraction will show irreversible cardiac damage. There is a need for a more advanced diagnostic tool to detect early cardiac dysfunction, to prevent further damage.

Main body

Advanced echocardiography imaging using strain imaging allows a physician to evaluate cardiac function more precisely. A more sensitive parameter than left ventricular ejection fraction, global longitudinal strain, can evaluate subclinical myocardial dysfunction before the symptoms occur by evaluating complex cardiac mechanisms. Global longitudinal strain evaluation provides the chance for physicians to determine the intervention needed to prevent further deterioration and permanent cardiac dysfunction. Global longitudinal strain is proven to be beneficial in many types of valvular heart diseases, especially in mitral and aortic valve diseases. It has an excellent diagnostic and prognostic value for patients with valve disease. This review aims to present the superiority of global longitudinal strain compared to left ventricular ejection fraction in assessing cardiac function in patients with valvular heart disease. Clinical usage of global longitudinal strain in several valvular heart diseases is also presented in this review.

Conclusions

The superiority of global longitudinal strain to left ventricular ejection fraction relies on the mechanism where other strains would compensate for the deterioration of longitudinal strain, which is more vulnerable to damage, so the cardiac function is preserved. Therefore, examination of longitudinal strain would give the physician early signs of cardiac function impairment, and prompt management can be conducted.

Automated Global Longitudinal Strain Exhibits a Robust Association with Death in Asymptomatic Chronic Aortic Regurgitation

BACKGROUND

Whether automated left ventricular global longitudinal strain (LVGLS) is associated with outcomes in asymptomatic aortic regurgitation (AR) is unknown.

OBJECTIVE

To explore the impact of automated LVGLS on survival and compare it with conventional LV parameters in chronic asymptomatic AR.

METHODS

LVGLS (presented as absolute value) was measured using fully-automated two-dimensional strain software in consecutive patients with isolated chronic ≥moderate-severe AR between 2004 and 2020; incremental value of LVGLS was assessed. Limited correction of endocardial border tracking was performed if needed.

RESULTS

Of 550 asymptomatic patients (age 60±17 years; 86% men), average LVGLS was 17±3% (1^st and 2^nd tertile, 15.8% and 18.5%). In 16% cases, tracking border was partially corrected; average time for analysis was 25±5 seconds. At a median (interquartile range) of 4.8(1.5-9.9) years, 87 patients had died (19 died after aortic-valve surgery [AVS]). Separate multivariable models adjusted for age, sex, Charlson index, AR severity and time-dependent AVS demonstrated that LVEF(hazard ratio[HR] per 10%: 0.9), LV end-systolic volume index(LVESVi; HR per 5ml/m²: 1.08) and LVGLS(HR per unit: 0.87) were independently associated with death(all p≤0.018); however, LVGLS remained statistically significant (HR: 0.86-0.9; P≤0.007) as compared head-to-head to LVEF, LVESVi and LV end-systolic dimension index(LVESDi). The association of LVGLS and mortality was consistent across all subgroups (P for interaction all≥0.08). Spline curves showed that continuous risk of death rose at LVGLS <15%. Those with LVGLS <15% had 2.6-fold risk of death [95% CI 1.54-4.23] while those with LVGLS <15% plus LVESVi≥45ml/m² had 3.96-fold risk[95% CI 1.94-8.03].

CONCLUSION

In this large cohort of asymptomatic patients with ≥moderate-severe AR, automated LVGLS was feasible, efficient, and independently associated with death on head-to-head comparison with conventional LVEF, LVESDi, and LVESVi. The automated-LVGLS threshold of <15% alone or combined with LVESVi≥45ml/m², was significantly associated with increased mortality risk and may be considered in early surgery decision-making.

The role of intraoperative pulmonary arterial catheterization data in determining the need for extracorporeal membrane oxygenation in lung transplantation

Background

This study aims to investigate predictive factors of identification of the need of patients for extracorporeal membrane oxygenation support during lung transplantation.

Methods

A total of 63 patients (49 males, 14 females, mean age: 44.9±14.4 years; range, 14 to 64 years) who underwent lung transplantation in our institution between December 2016 and December 2019 were retrospectively analyzed. Demographic characteristics and perioperative clinical data of patients were recorded. After induction and pulmonary artery catheterization, cardiac output, mean pulmonary artery pressure, pulmonary capillary wedge pressure, cardiac index, pulmonary vascular resistance, systemic vascular resistance, and right atrial pressure were measured using the thermodilution technique.

Results

Thirty-three of the patients received extracorporeal membrane oxygenation support during surgery. The right atrial pressure (p<0.001), pulmonary capillary wedge pressure (p<0.002), mean pulmonary artery pressure (p<0.001), and pulmonary vascular resistance (p<0.001) were statistically significantly higher in the patients who required extracorporeal membrane oxygenation support intraoperatively. The systemic vascular resistance (p<0.032) was statistically significantly lower in the patients who required extracorporeal membrane oxygenation support intraoperatively. A mean pulmonary artery pressure of >39 mmHg (p<0.02) and a right atrial pressure of >12 mmHg (p<0.047) were independent risk factors for ECMO support intraoperatively during lung transplantation.

Conclusion

Predicting the need of intraoperative extracorporeal membrane oxygenation support is of utmost importance in timing the need for mechanical support, protecting the new graft from high mechanical ventilator pressures, and adequately maintaining hemodynamic stability.

Updated knowledge and practical implementations of stress echocardiography in ischemic and non-ischemic cardiac diseases: an expert consensus of the Working Group of Echocardiography of the Hellenic Society of Cardiology

Stress echocardiography (SE) is a well-established and valid technique, widely-used for the diagnostic evaluation of patients with ischemic and non-ischemic cardiac diseases. This statement of the Echocardiography Working Group of the Hellenic Society of Cardiology summarizes the consensus of the writing group regarding the applications of SE, based on the expertise of their members and on a critical review of current medical literature. The main objectives of the consensus document include a comprehensive review of SE methodology and training, focusing on the preparation, the protocols used and the analysis of the SE images and an updated, evidence-based knowledge about SE applications on ischemic and non-ischemic heart diseases, such as in cardiomyopathies, heart failure and valvular heart disease.

Valvular Disease and Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is a clinical syndrome of shortness of breath and/or exercise intolerance secondary to elevated left ventricular filling pressures at rest or with exertion either as a result of primary diastolic dysfunction (primary HFpEF) or secondary to specific underlying causes (secondary HFpEF). In secondary HFpEF, early intervention of underlying valvular heart disease generally improves symptoms and prolongs survival. In primary HFpEF, there is increasing awareness of the existence and prognostic implications of secondary atrioventricular valve regurgitation. Further studies will clarify their mechanisms and the effectiveness of valvular intervention in this intriguing HFpEF subgroup.

Review: application of current imaging modalities in the management of left-sided valvular heart disease

In terms of valvular heart disease (VHD) imaging, transthoracic echocardiography (TTE) is the preferred first choice because of its widespread availability. Other modalities, such as transesophageal echocardiography, computed tomography and magnetic resonance imaging, have played a supplementary role in diagnosis for severity, deciding the timing/type of treatment, detection of post procedural complications, and prognostic predictions. However, there are few consensuses on how to employ these modalities, as the evidence is not extensive as that for TTE. On the other hand, these imaging modalities also have their own unique strengths. If employed properly, these modalities have the potential to play a more prominent role in clinical decision making. In this review, we focus on the potential, limitations and application of current imaging modalities in the management of left-sided VHD.

Feasibility of CT-derived myocardial strain measurement in patients with advanced cardiac valve disease

To explore the feasibility of CT-derived myocardial strain measurement in patients with advanced cardiac valve disease and to compare it to strain measurements derived from transthoracic echocardiography (TTE). 43 consecutive patients with advanced cardiac valve disease and clinically indicated retrospectively gated cardiac CTs were retrospectively analyzed. The longitudinal, circumferential as well as radial systolic strain were determined in all patients utilizing a commercially available CT strain software. In 36/43 (84%) patients, CT-derived longitudinal strain was compared to speckle-tracking TTE. Pearson’s correlation coefficients as well as Bland–Altman analysis were used to compare the CT-derived strain measurements to TTE. The intra- and inter-reader-reliability of the CT-derived strain measurements were assessed by intra-class correlation coefficients (ICCs). Strain measurements were feasible in all patients. CT-derived global longitudinal strain (GLS) correlated moderately with TTE-derived GLS (r = 0.6, p < 0.001). A moderate correlation between CT-derived GLS and CT-derived left ventricular ejection fraction was found (LVEF, r = − 0.66, p = 0.036). Bland–Altman analysis showed a systematic underestimation of myocardial strain by cardiac CT compared to TTE (mean difference: − 5.8%, 95% limit of agreement between − 13.3 and 1.8%). Strain measurements showed an excellent intra- and inter-reader-reliability with an intra-reader ICC of 1.0 and an inter-reader ICC of 0.99 for GLS measurements. CT-derived myocardial strain measurements are feasible in patients with advanced cardiac valve disease. They are highly reproducible and correlate with established parameters of strain measurements. Our results encourage the implementation of CT-derived strain measurement into clinical routine.

The Role of Extravalvular Cardiac Damage Staging in Aortic Valve Disease Management

Current management of patients with aortic valve disease, including aortic valve stenosis (AS), aortic valve regurgitation (AR), and mixed aortic valve disease (MAVD), remains challenging. American and European guideline recommendations regarding the timing of intervention are mainly based on the assessment of disease severity (ie, grading), presence of symptoms related to aortic valve disease, left ventricular systolic dysfunction, or LV enlargement. Furthermore, the decision regarding the type of intervention (ie, surgical vs transcatheter) is primarily based on risk assessment from surgical risk scores. There is, however, less emphasis on the importance of the assessment of anatomic and functional cardiac repercussions of aortic valve disease to guide the clinical management of these patients. Recently, a novel approach has been proposed to improve the management of aortic valve disease with 2 main components for risk stratification of the disease: 1) grading the severity of aortic valve disease, and 2) staging the extent of extravalvular cardiac damage associated with aortic valve disease with the use of echocardiography. To date, this novel approach of extravalvular cardiac damage staging was proposed and validated only in the context of AS but could be extended to other valvular heart diseases, including AR and MAVD. Further studies are also needed to test the incremental value of additional imaging parameters (eg, myocardial fibrosis by magnetic resonance) as well as blood biomarkers (eg, natriuretic peptide, cardiac troponin, and others) to the existing cardiac damage staging schemes.

Association of Echocardiographic Left Ventricular End-Systolic Volume and Volume-Derived Ejection Fraction With Outcome in Asymptomatic Chronic Aortic Regurgitation

Importance

Volumetric measurements by transthoracic echocardiogram may better reflect left ventricular (LV) remodeling than conventional linear LV dimensions. However, the association of LV volumes with mortality in patients with chronic hemodynamically significant aortic regurgitation (AR) is unknown.

Objective

To assess whether LV volumes and volume-derived LV ejection fraction (Vol-LVEF) are determinants of mortality in AR.

Design, Setting, and Participants

This cohort study included consecutive asymptomatic patients with chronic moderately severe to severe AR from a tertiary referral center (January 2004 through April 2019).

Exposures

Clinical and echocardiographic data were analyzed retrospectively. Aortic regurgitation severity was graded by comprehensive integrated approach. De novo disk-summation method was used to derive LV volumes and Vol-LVEF.

Main Outcome and Measures

Associations between all-cause mortality under medical surveillance and the following LV indexes: linear LV end-systolic dimension index (LVESDi), linear LVEF, LV end-systolic volume index (LVESVi), and Vol-LVEF.

Results

Of 492 asymptomatic patients (mean [SD] age, 60 [17] years; 425 men [86%]), ischemic heart disease prevalence was low (41 [9%]), and 453 (92.1%) had preserved linear LVEF (≥50%) with mean (SD) LVESVi of 41 (15) mL/m2. At a median (interquartile range) of 5.4 (2.5-10.1) years, 66 patients (13.4%) died under medical surveillance; overall survival was not different than the age- and sex-matched general population (P = .55). Separate multivariate models, adjusted for age, sex, Charlson Comorbidity Index, and AR severity, demonstrated that in addition to linear LVEF and LVESDi, LVESVi and Vol-LVEF were independently associated with mortality under surveillance (all P < .046) with similar C statistics (range, 0.83-0.84). Spline curves showed that continuous risks of death started to rise for both linear LVEF and Vol-LVEF less than 60%, LVESVi more than 40 to 45 mL/m2, and LVESDi above 21 to 22 mm/m2. As dichotomized variables, patients with LVESVi more than 45 mL/m2 exhibited increased relative death risk (hazard ratio, 1.93; 95% CI, 1.10-3.38; P = .02) while LVESDi more than 20 mm/m2 did not (P = .32). LVESVi more than 45 mL/m2 showed a decreased survival trend compared with expected population survival.

Conclusions and Relevance

In this large asymptomatic cohort of patients with hemodynamically significant AR, LVESVi and Vol-LVEF worked equally as well as LVESDi and linear LVEF in risk discriminating patients with excess mortality. A LVESVi threshold of 45 mL/m2 or greater was significantly associated with an increased mortality risk.

Time course of left ventricular remodelling and mechanics after aortic valve surgery: aortic stenosis vs. aortic regurgitation

Aims

Pressure overload in aortic stenosis (AS) and both pressure and volume overload in aortic regurgitation (AR) induce concentric and eccentric hypertrophy, respectively. These structural changes influence left ventricular (LV) mechanics, but little is known about the time course of LV remodelling and mechanics after aortic valve surgery (AVR) and its differences in AS vs. AR. The present study aimed to characterize the time course of LV mass index (LVMI) and LV mechanics [by LV global longitudinal strain (LV GLS)] after AVR in AS vs. AR.

Methods and results

Two hundred and eleven (61 ± 14 years, 61% male) patients with severe AS (63%) or AR (37%) undergoing surgical AVR with routine echocardiographic follow-up at 1, 2, and/or 5 years were evaluated. Before AVR, LVMI was larger in AR patients compared with AS. Both groups showed moderately impaired LV GLS, but preserved LV ejection fraction. After surgery, both groups showed LV mass regression, although a more pronounced decline was seen in AR patients. Improvement in LV GLS was observed in both groups, but characterized by an initial decline in AR patients while LV GLS in AS patients remained initially stable.

Conclusion

In severe AS and AR patients undergoing AVR, LV mass regression and changes in LV GLS are similar despite different LV remodelling before AVR. In AR, relief of volume overload led to reduction in LVMI and an initial decline in LV GLS. In contrast, relief of pressure overload in AS was characterized by a stable LV GLS and more sustained LV mass regression.

2- and 3-Dimensional Myocardial Strain in Cardiac Health and Disease

Advances in speckle-tracking echocardiography allowed the rise of deformation imaging as a feasible, robust, and valuable tool for clinical routine. The global or segmental measurement of strain can objectively quantify myocardial deformation and can characterize myocardial function in a novel way. However, the proper interpretation of deformation measurements requires understanding of cardiac mechanics and the influence of loading conditions, ventricular geometry, conduction delays, and myocardial tissue characteristics on the measured values. The purpose of this manuscript is to review the basic concepts of deformation imaging, briefly describe imaging modalities for strain assessment, and discuss in depth the underlying physical and pathophysiological mechanisms which lead to the respective findings in a specific disease.

Application of strain echocardiography in valvular heart diseases

Echocardiographic strain imaging allows new insight into a complex cardiac mechanics and enables more precise evaluation of cardiac function. Hence, it has been shown to have clinical utility in a variety of valvular heart diseases. In particular, global longitudinal strain has been shown to be more sensitive to detect systolic dysfunction than left ventricular ejection fraction. In patients with valvular heart diseases, it provides both diagnostic and prognostic information in addition to standard echocardiographic and clinical parameters. In this review, we summarize current clinical application of strain echocardiography in patients with valvular heart diseases and discuss pathophysiological mechanisms that lead to respective findings in specific diseases.

Long-Term Outcomes in Patients With Mixed Aortic Valve Disease and Preserved Left Ventricular Ejection Fraction

Background

Concurrent presence of aortic stenosis and aortic regurgitation is termed mixed aortic valve disease (MAVD). Although multiple articles have addressed patients with “isolated” aortic stenosis or aortic regurgitation, the natural history, impact, and outcomes of MAVD are not well defined. Here, we evaluate long‐term outcomes in patients with MAVD and cardiovascular adaptations to chronic MAVD.

Methods and Results

This observational cohort study evaluated 862 adult patients (56.8% male) with preserved left ventricular ejection fraction and at least moderate aortic regurgitation and moderate aortic stenosis. Primary outcome was all‐cause mortality. Subgroup analysis was based on treatment modality (aortic valve replacement [AVR] versus medical management). A regression analysis of longitudinal echocardiographic parameters was performed to assess the natural history of MAVD. Mean age was 68±15 years, and mean left ventricular ejection fraction was 58±5%. At 4.6 years (25th–75th percentile range, 1.0–8.7), 58.6% of patients underwent an AVR and 48.8% patients died. In both unadjusted and adjusted Cox survival analysis, AVR was associated with improved survival (hazard ratio, 0.41; 95% CI, 0.34–0.51, P<0.001). Impact of AVR persisted when stratifying the cohort by symptom status and baseline aortic valve area (log rank, P<0.001 for both) and after propensity‐score matching (hazard ratio, 0.40; 95% CI, 0.32–0.50; P<0.001). In the longitudinal analysis, there were statistically significant changes over time in aortic valve peak gradient (P<0.001) and aortic valve area (P<0.001) and only mild increases in left ventricular end‐diastolic (P<0.007) and ‐systolic (P<0.001) volumes.

Conclusions

MAVD confers a high risk of all‐cause mortality. However, AVR significantly reduces this risk independent of aortic valve area, symptom status, and after controlling for confounding variables.

New Imaging Markers of Clinical Outcome in Asymptomatic Patients with Severe Aortic Regurgitation

Background: Determining the value of new imaging markers to predict aortic valve (AV) surgery in asymptomatic patients with severe aortic regurgitation (AR) in a prospective, observational, multicenter study. Methods: Consecutive patients with chronic severe AR were enrolled between 2015–2018. Baseline examination included echocardiography (ECHO) with 2- and 3-dimensional (2D and 3D) vena contracta area (VCA), and magnetic resonance imaging (MRI) with regurgitant volume (RV) and fraction (RF) analyzed in CoreLab. Results: The mean follow-up was 587 days (interquartile range (IQR) 296–901) in a total of 104 patients. Twenty patients underwent AV surgery. Baseline clinical and laboratory data did not differ between surgically and medically treated patients. Surgically treated patients had larger left ventricular (LV) dimension, end-diastolic volume (all p < 0.05), and the LV ejection fraction was similar. The surgical group showed higher prevalence of severe AR (70% vs. 40%, p = 0.02). Out of all imaging markers 3D VCA, MRI-derived RV and RF were identified as the strongest independent predictors of AV surgery (all p < 0.001). Conclusions: Parameters related to LV morphology and function showed moderate accuracy to identify patients in need of early AV surgery at the early stage of the disease. 3D ECHO-derived VCA and MRI-derived RV and RF showed high accuracy and excellent sensitivity to identify patients in need of early surgery.

Clinical application of stress echocardiography for valvular heart disease

Stress echocardiography is widely used to assess several cardiovascular diseases, including ischemic heart disease, valvular heart disease (VHD), heart failure, congenital heart disease, and pulmonary hypertension. In valvular heart disease with asymptomatic severe or symptomatic non-severe status, stress echocardiography plays a central role in the management. As of 2017, the updated American College of Cardiology/American Heart Association and European Society of Cardiology/European Association for Cardio-Thoracic Surgery VHD guidelines recommended stress testing to (1) confirm symptoms and (2) evaluate the hemodynamic response to exercise. In patients with undetermined VHD severity in the presence of low-flow status, it can also be helpful to determine whether the VHD is severe based on flow-dependent changes in response to stress. The clinical indications of stress echocardiography in VHD have expanded with growing evidence for prognosis and being an early marker for interventions. As a result, demand has increased in major cardiology societies for the standardization of stress echocardiography in VHD. Echocardiographic centers should be aware of the clinical potential of stress echocardiography to ensure its optimal application and performance in VHD. This article reviews the clinical application of stress echocardiography, including dobutamine, semisupine bicycle, treadmill, and leg-positive pressure for VHD patient management, and focuses on the current consensus regarding the use of stress echocardiography in VHD. Stress echocardiography is safe and should be encouraged, especially in heart valve clinics, to understand the complex mechanism in asymptomatic patients.

Stress ECHO beyond coronary artery disease. Is it the holy grail of cardiovascular imaging?

Stress echocardiography (SE) is a very useful method in clinical practice, because it offers important information of both the patient's functional status and hemodynamic changes during stress. Therefore, SE provides strong diagnostic and prognostic data in a wide spectrum of cardiovascular diseases. This review summarizes the clinical applications of SE in conditions beyond coronary artery disease (CAD) and highlights practical recommendations and key issues for each condition that need further investigation. SE is an established method for the evaluation of symptomatic and asymptomatic patients with valvular heart disease (VHD) and cardiomyopathies, and provides important information regarding prognosis and management of patients with congenital heart disease, pulmonary hypertension or diastolic dysfunction. Moreover, when one or multiple VHD and cardiomyopathy or CAD coexist in one patient, SE is a very useful clinical tool for the evaluation of etiology and symptomatology.

Stress echocardiography in valvular heart disease

INTRODUCTION

The management of patients with heart valve disease can be complex. Patients may have symptoms disproportionate to the severity or the severity may be unclear. In addition, the optimal timing of intervention in patients with severe disease may be controversial. Areas covered: This article examines the role of stress echocardiography for assessment of patients with low-flow, low-gradient aortic stenosis, asymptomatic severe valve disease and patients where symptoms are discordant to the resting severity of valve disease. Expert commentary: Stress echocardiography helps clinicians determine the true severity of valve disease and may identify the cause of symptoms in patients with only mild/moderate disease. The data provided by stress echocardiography will help determine the appropriate management strategy and the correct timing of intervention.

A Novel Hierarchical Template Matching Model for Cardiac Motion Estimation

Cardiovascular disease diagnosis and prognosis can be improved by measuring patient-specific in-vivo local myocardial strain using Magnetic Resonance Imaging. Local myocardial strain can be determined by tracking the movement of sample muscles points during cardiac cycle using cardiac motion estimation model. The tracking accuracy of the benchmark Free Form Deformation (FFD) model is greatly affected due to its dependency on tunable parameters and regularisation function. Therefore, Hierarchical Template Matching (HTM) model, which is independent of tunable parameters, regularisation function, and image-specific features, is proposed in this article. HTM has dense and uniform points correspondence that provides HTM with the ability to estimate local muscular deformation with a promising accuracy of less than half a millimetre of cardiac wall muscle. As a result, the muscles tracking accuracy has been significantly (p < 0.001) improved (30%) compared to the benchmark model. Such merits of HTM provide reliably calculated clinical measures which can be incorporated into the decision-making process of cardiac disease diagnosis and prognosis.

Stress echocardiography in patients with native valvular heart disease

Valve stress echocardiography (VSE) can be performed as exercise stress echocardiography (ESE) or dobutamine stress echocardiography (DSE) depending on the patient’s clinical status, severity and type of valve disease. ESE combines exercise testing with two-dimensional grey scale and Doppler echocardiography during exercise. Thus, it provides objective assessment of symptomatic status (exercise test), as well as exercise-induced changes of a series of echocardiographic parameters (different depending on the valve disease type), which yield prognostic information in individual patients and help in a better treatment planning. DSE is useful in symptomatic patients with low-gradient aortic stenosis. It clarifies its severity and helps in assessing surgical risk in patients with severe disease and systolic dysfunction. It can be also used to test valve haemodynamics in asymptomatic patients with significant mitral stenosis unable to perform an exercise test or to test the left ventricle response, namely to test viability, in patients with ischaemic secondary mitral regurgitation. VSE has taught us that history taking, clinical examination and resting echocardiography give an ‘incomplete picture’ of the disease in patients presenting with a severe valve disease. Therefore, its use should be encouraged in such patients.

Comparison of effects of losartan and metoprolol on left ventricular and aortic function at rest and during exercise in chronic aortic regurgitation

Aortic regurgitation (AR) increases the hemodynamic load on both the left ventricle (LV) and the aorta. Vasodilators and beta-blockers both reduce systemic blood pressure, but their relative effects on the LV and aortic function and aortic regurgitant fraction in chronic AR are uncertain. We aimed to compare short-term effects of losartan and metoprolol on LV and aortic function in asymptomatic patients with chronic moderate to severe AR, both at rest and during exercise, using cardiac magnetic resonance (CMR) imaging. 17 chronic AR patients were randomized to 4-6 weeks losartan followed by metoprolol, or vice versa, in a cross-over design. Aortic regurgitant fraction, aortic distensibility, pulse wave velocity and LV function were assessed at rest and after moderate exercise stress (29 ± 7 W, heart rate increase 25 ± 6 bpm) using CMR. Chronic AR patients on metoprolol had a significantly lower mean heart rate, cardiac power index and rate-pressure product, than on losartan (all p < 0.01). However, aortic regurgitant fraction was greater on metoprolol compared to losartan (by 7 ± 11%, p = 0.02). Metoprolol was also associated with a greater reduction in aortic distensibility during exercise than losartan (- 2.4 ± 1.5 × 10^-3 vs - 1.7 ± 2.1 × 10^-3 mmHg^-1 respectively, p = 0.04). End-diastolic volume index was higher on metoprolol than losartan at exercise (difference 6.6 ± 7.8 ml/m², p < 0.01), as was end-systolic volume index (difference 4.0 ± 5.2 ml/m², p < 0.01). Losartan and metoprolol have significantly different short-term effects on aortic regurgitation and LV and aortic function in chronic AR. Further research is required to determine the long-term clinical significance of these changes.

Role of Two-Dimensional Speckle-Tracking Echocardiography Strain in the Assessment of Right Ventricular Systolic Function and Comparison with Conventional Parameters

Despite the already well-known role the right side of the heart plays in many diseases, right ventricular (RV) function has only recently been carefully considered. Echocardiography is the first-line diagnostic technique for the assessment of the right ventricle and right atrium, whereas cardiac magnetic resonance is considered the gold standard but is limited by cost and availability. According to the current guidelines, systolic RV function should be assessed by several conventional measurements, but the efficacy of these parameters as diagnostic and prognostic tools has been questioned by many authors. The development in recent years of myocardial deformation imaging techniques and their application to the right heart chambers has allowed deeper evaluation of the importance of RV function in the pathophysiology of a large number of cardiovascular conditions, but the real value of this new tool has not been completely clarified. The aim of this review is to provide a wide and careful analysis of findings available in the literature about the assessment of RV systolic function by strain measurements, comparing them with conventional parameters and evaluating their role in several clinical settings.

Assessment of aortic valve disease - a clinician oriented review

Aortic valve disease [aortic stenosis (AS) and aortic regurgitation (AR)] represents an important global health problem; when severe, aortic valve disease carries poor prognosis. For AS, aortic valve replacement, either surgical or interventional, may provide definite treatment in carefully selected patients. For AR, valve surgery (either replacement or - in selected cases - aortic valve repair) remains the gold standard of care. To properly identify those patients who are candidates for surgery, the clinician has to carefully assess the severity of valve disease with an understanding of the potential pitfalls involved in these assessments. This review focuses on the practical issues concerning the evaluation of patients with AS and AR from a general cardiologist’s perspective. The most important issues regarding the documentation of the severity of AS and AR are summarized. More specific issues, such as the role of stress echocardiography, other imaging techniques and details regarding the treatment options (medical, surgical, or interventional), are mentioned briefly.

Incremental Prognostic Utility of Left Ventricular Global Longitudinal Strain in Asymptomatic Patients With Significant Chronic Aortic Regurgitation and Preserved Left Ventricular Ejection Fraction

OBJECTIVES

This study sought to examine the prognostic utility of left ventricular (LV) global longitudinal strain (GLS) in asymptomatic patients with ≥III+ aortic regurgitation (AR), an indexed LV end-systolic dimension of <2.5 cm/m², and preserved left ventricular ejection fraction (LVEF).

BACKGROUND

Management of asymptomatic patients with severe chronic AR and preserved LVEF is challenging and is typically based on LV dimensions.

METHODS

We studied 1,063 such patients (age 53 ± 16 years; 77% men) seen between 2003 and 2010 (excluding those with symptoms, obstructive coronary artery disease, acute AR/dissection, aortic/mitral stenosis, more than moderate mitral regurgitation, and previous cardiac surgery). Society of Thoracic Surgeons (STS) score was calculated. The primary endpoint was mortality. Average resting LV-GLS was measured offline on 2-, 3-, and 4-chamber views using Velocity Vector Imaging (Siemens, Malvern, Pennsylvania).

RESULTS

Mean STS score, LVEF, LV-GLS, and right ventricular systolic pressure were 4.4 ± 5.0%, 57.0 ± 4.0%, -19.5 ± 0.2%, and 31.0 ± 9.0 mm Hg, respectively. In total, 671 patients (63%) underwent aortic valve surgery at a median of 42 days after the initial evaluation. At 6.8 ± 3.0 years, 146 patients (14%) had died. On multivariable Cox survival analysis, LV-GLS (hazard ratio [HR]: 1.11), STS score (HR: 1.51), indexed LV end-systolic dimension (HR: 0.50), right ventricular systolic pressure (HR: 1.33), and aortic valve surgery (HR: 0.35) were associated with longer term mortality (all p < 0.001). Sequential addition of LV-GLS and aortic valve surgery improved the C-statistic for longer term mortality for the clinical model (STS score + right ventricular systolic pressure + indexed LV end-systolic dimension) from 0.61 (95% confidence interval [CI]: 0.51 to 0.72) to 0.67 (95% CI: 0.54 to 0.87) and to 0.77 (95% CI: 0.63 to 0.90), respectively (p < 0.001 for both). A significantly higher proportion (log-rank p = 0.01) of patients with LV-GLS worse than median (-19.5%) died versus those with an LV-GLS better than median (86 of 513 [17%] vs. 60 of 550 [11%]). The risk of death at 5 years significantly increased with an LV-GLS of worse than -19%.

CONCLUSIONS

In asymptomatic patients with ≥III+ chronic AR and preserved LVEF, worsening LV-GLS was associated with longer term mortality, providing incremental prognostic value and improved reclassification.

Functional assessment of the diaphragm by speckle tracking ultrasound during inspiratory loading

Assessment of diaphragmatic effort is challenging, especially in critically ill patients in the phase of weaning. Fractional thickening during inspiration assessed by ultrasound has been used to estimate diaphragm effort. It is unknown whether more sophisticated ultrasound techniques such as speckle tracking are superior in the quantification of inspiratory effort. This study evaluates the validity of speckle tracking ultrasound to quantify diaphragm contractility. Thirteen healthy volunteers underwent a randomized stepwise threshold loading protocol of 0-50% of the maximal inspiratory pressure. Electric activity of the diaphragm and transdiaphragmatic pressures were recorded. Speckle tracking ultrasound was used to assess strain and strain rate as measures of diaphragm tissue deformation and deformation velocity, respectively. Fractional thickening was assessed by measurement of diaphragm thickness at end-inspiration and end-expiration. Strain and strain rate increased with progressive loading of the diaphragm. Both strain and strain rate were highly correlated to transdiaphragmatic pressure (strain r² = 0.72; strain rate r² = 0.80) and diaphragm electric activity (strain r² = 0.60; strain rate r² = 0.66). We conclude that speckle tracking ultrasound is superior to conventional ultrasound techniques to estimate diaphragm contractility under inspiratory threshold loading.NEW & NOTEWORTHY Transdiaphragmatic pressure using esophageal and gastric balloons is the gold standard to assess diaphragm effort. However, this technique is invasive and requires expertise, and the interpretation may be complex. We report that speckle tracking ultrasound can be used to detect stepwise increases in diaphragmatic effort. Strain and strain rate were highly correlated with transdiaphragmatic pressure, and therefore, diaphragm electric activity and speckle tracking might serve as reliable tools to quantify diaphragm effort in the future.

The Role of Stress Echocardiography in Valvular Heart Disease: A Current Appraisal

Stress echocardiography is a widely available, safe, low-cost, versatile imaging modality which is becoming increasingly recognized as a valuable tool in the assessment of patients with native and prosthetic left-sided valvular heart disease. It provides a quantitative assessment to help guide clinical decision-making when discordance exists between symptoms and severity of valve disease. Exercise (treadmill or bicycle) remains the preferred stress modality, but pharmacological augmentation with dobutamine can be used if needed. Low-dose dobutamine stress echocardiography is specifically valuable in patients with low-flow, low-gradient aortic stenosis when attempting to differentiate true severe aortic stenosis from pseudo-severe aortic stenosis. Stress echocardiography not only identifies high-risk features that indicate need for earlier surgery, it also provides useful information for the peri- and postoperative period, including long-term outcome, risk stratification to guide monitoring frequency, and offers guidance for eligibility in competitive sports participation. As research continues to expand the utility of stress echocardiography in the management of patients with valvular heart disease, future research should focus on the recognition of newer parameters identifying high-risk features including subsequent validation in a large population.

Advanced imaging in valvular heart disease

Although echocardiography remains the mainstay imaging technique for the evaluation of patients with valvular heart disease (VHD), innovations in noninvasive imaging in the past few years have provided new insights into the pathophysiology and quantification of VHD, early detection of left ventricular (LV) dysfunction, and advanced prognostic assessment. The severity grading of valve dysfunction has been refined with the use of Doppler echocardiography, cardiac magnetic resonance (CMR), and CT imaging. LV ejection fraction remains an important criterion when deciding whether patients should be referred for surgery. However, echocardiographic strain imaging can now detect impaired LV systolic function before LV ejection fraction reduces, thus provoking the debate on whether patients with severe VHD should be referred for surgery at an earlier stage (before symptom onset). Impaired LV strain correlates with the amount of myocardial fibrosis detected with CMR techniques. Furthermore, accumulating data show that the extent of fibrosis associated with severe VHD has important prognostic implications. The present Review focuses on using these novel imaging modalities to assess pathophysiology, early LV dysfunction, and prognosis of major VHDs, including aortic stenosis, mitral regurgitation, and aortic regurgitation.