Myocardial Systolic Velocities and Deformation Assessed by Speckle Tracking for Early Detection of Left Ventricular Dysfunction in Asymptomatic Patients with Severe Primary Mitral Regurgitation

Perioperative echocardiographic strain analysis: what anesthesiologists should know

PURPOSE

Echocardiographic strain analysis by speckle tracking allows assessment of myocardial deformation during the cardiac cycle. Its clinical applications have significantly expanded over the last two decades as a sensitive marker of myocardial dysfunction with important diagnostic and prognostic values. Strain analysis has the potential to become a routine part of the perioperative echocardiographic examination for most anesthesiologist-echocardiographers but its exact role in the perioperative setting is still being defined.

CLINICAL FEATURES

This clinical report reviews the principles underlying strain analysis and describes its main clinical uses pertinent to the field of anesthesiology and perioperative medicine. Strain for assessment of left and right ventricular function as well as atrial strain is described. We also discuss the potential role of strain to aid in perioperative risk stratification, surgical patient selection in cardiac surgery, and guidance of anesthetic monitor choice and clinical decision-making in the perioperative period.

CONCLUSION

Echocardiographic strain analysis is a powerful tool that allows seeing what conventional 2D imaging sometimes fails to reveal. It often provides pathophysiologic insight into various cardiac diseases at an early stage. Strain analysis is readily feasible and reproducible thanks to the use of highly automated software platforms. This technique shows promising potential to become a valuable tool in the arsenal of the anesthesiologist-echocardiographer and aid in perioperative risk-stratification and clinical decision-making.

Moving from left ventricular ejection fraction to deformation imaging in mitral valve regurgitation

The increasing prevalence of valvular heart diseases, specifically mitral regurgitation (MR), underscores the need for a careful and timely approach to intervention. Severe MR, whether primary or secondary, when left untreated leads to adverse outcomes, emphasizing the critical role of a timely surgical or transcatheter intervention. While left ventricular ejection fraction (LVEF) remains the guideline-recommended measure for assessing left ventricle damage, emerging evidence raises concerns regarding its reliability in MR due to its volume-dependent nature. This review summarizes the existing literature on the role of LVEF and deformation imaging techniques, emphasizing the latter's potential in providing a more accurate evaluation of intrinsic myocardial function. Moreover, it advocates the need for an integrated approach that combines traditional with emerging measures, aiming to optimize the management of patients with MR. It attempts to highlight the need for future research to validate the clinical application of deformation imaging techniques through large-scale studies.

Primary mitral regurgitation: Toward a better quantification on left ventricular consequences

BACKGROUND

Left ventricular end-systolic diameter (LVESD) and ejection fraction (LVEF) are the parameters to look for when discussing repair in asymptomatic patients with a primary mitral regurgitation (PMR). Loading conditions are altering LV-function quantification. LV-myocardial work (LVMW) is a method based on pressure-strain loops.

HYPOTHESIS

We sought to evaluate the additive value of the LVMW for predicting clinical events in patients with PMR.

METHODS

103 patients (66% men, median age 57 years) with asymptomatic severe PMR were explored at rest and during an exercise stress echocardiography. LV myocardial global work index (GWI), constructive work (GCW), wasted work (GWW), and work efficiency (GWE) were measured with speckle-tracking echocardiography at rest and low workload. The indication for surgery was based on the heart teams' decision. The median follow-up was 670 days.

RESULTS

Clinical events occurred for 50 patients (48.5%) with a median of event-free survival distribution of 289 days. Systolic pulmonary artery pressure (sPAP) at rest was 32.61 ± 8.56 mmHg and did not predict the risk of event like LVEF and LVESD. Changes in, GLS (hazard ratio [HR] 0.55; 95% confidence interval (Cl): 0.36-0.83; p = .005), GWI (HR 1.01; 95% Cl: 1.00-1.02; p = .002) and GCW (HR 1.85; 95% Cl: 1.28-2.68; p = .001) in addition to Left Atrial Volume Index (HR 1.73; 95% CI: 1.28 - 2.33; p < 0,001) were independent predictors of events.

CONCLUSION

Changes in myocardial work indices related to low-dose exercise are relevant to best predict PMR patient prognosis It might help to better select patient's candidate for "early-surgery."

Arrhythmic Mitral Valve Prolapse: A Comprehensive Review

Mitral valve prolapse (MVP) is a prevalent cardiac disorder that impacts approximately 2% to 3% of the overall population. While most patients experience a benign clinical course, there is evidence suggesting that a subgroup of MVP patients face an increased risk of sudden cardiac death (SCD). Although a conclusive causal link between MVP and SCD remains to be firmly established, various factors have been associated with arrhythmic mitral valve prolapse (AMVP). This study aims to provide a comprehensive review encompassing the historical background, epidemiology, pathology, clinical manifestations, electrocardiogram (ECG) findings, and treatment of AMVP patients. A key focus is on utilizing multimodal imaging techniques to accurately diagnose AMVP and to highlight the role of mitral annular disjunction (MAD) in AMVP.

Prognostic value of left ventricular global longitudinal strain in mitral regurgitation: a systematic review

Conventional echocardiographic assessment may overestimate the left ventricular (LV) function in mitral regurgitation (MR). LV global longitudinal strain (GLS) is more sensitive marker to detect subclinical LV dysfunction. Multiple studies have investigated the prognostic value of LV-GLS in MR to examine its potential to determine the timing and indication of intervention. This systematic review aimed to assess the prognostic value of LV-GLS in patients with mitral regurgitation (MR) to define its clinical applicability. PUBMED and EMBASE were queried through July 2021 to identify studies investigating the prognostic value of LV-GLS in MR. A total of 24 observational studies with 5267 patients were identified. Sixteen studies investigated for primary MR, 7 studies for secondary MR, and 1 study for both. Most studies included patients who underwent intervention. There was significant heterogeneity in patient population, intervention status, follow-up period, LV-GLS cutoff value, outcomes, and statistical methods among the studies. Meta-analysis was not performed considering the significant variability. With exception to 1 study, all studies demonstrated significant association between impaired LV-GLS and worse clinical and echocardiographic outcomes in primary MR. Prognostic value of LV-GLS in secondary MR was less certain due to inconsistent findings and limited reporting. LV-GLS is a promising parameter of prognostication in primary MR and can be considered as alternative to determine the timing of intervention. However, the optimal cutoff value remains unclear. The prognostic value of LV-GLS in secondary MR is less clear. Further large-scale prospective study is warranted before its routine clinical application.

New insights into the potential utility of the left atrial function analysis in heart failure with preserved ejection fraction diagnosis

Aims

None of the conventional echocardiographic parameters alone predict increased NTproBNP level and symptoms, making diagnosis of heart failure with preserved ejection fraction (HFpEF) very difficult in some cases, in resting condition. We evaluated LA functions by 2D speckle tracking echocardiography (STE) on top of conventional parameters in HFpEF and preHF patients with diastolic dysfunction (DD), in order to establish the added value of the LA deformation parameters in the diagnosis of HFpEF.

Methods

We prospectively enrolled 125 patients, 88 with HFpEF (68±9 yrs), and 37 asymptomatic with similar risk factors with DD (preHF) (61±8 yrs). We evaluated them by NTproBNP, conventional DD parameters, and STE. Global longitudinal strain (GS) was added. LA reservoir (R), conduit (C), and pump function (CT) were assessed both by volumetric and STE. 2 reservoir strain (S) derived indices were also measured, stiffness (SI) and distensibility index (DI).

Results

LA R and CT functions were significantly reduced in HFpEF compared to preHF group (all p<0.001), whereas conduit was similarly in both groups. SI was increased, whereas DI was reduced in HFpEF group (p<0.001). By adding LA strain analysis, from all echocardiographic parameters, SR_CT<-1.66/s and DI<0.57 (AUC = 0.76, p<0.001) demonstrated the highest accuracy to identify HFpEF diagnosis. However, by multivariate logistic regression, the model that best identifies HFpEF included only SR_CT, GS and sPAP (R² = 0.506, p<0.001). Moreover, SR_CT, DI, and sPAP registered significant correlation with NTproBNP level.

Conclusions

By adding LA functional analysis, we might improve the HFpEF diagnosis accuracy, compared to present guidelines. LA pump function is the only one able to differentiates preHF from HFpEF patients at rest. A value of SR_CT < -1.66/s outperformed conventional parameters from the scoring system, reservoir strain, and LA overload indices in HFpEF diagnosis. We suggest that LA function by STE could be incorporated in the current protocol for HFpEF diagnosis at rest as a major functional criterion, in order to improve diagnostic algorithm, and also in the follow-up of patients with risk factors and DD, as a prognostic marker. Future studies are needed to validate our findings.

Global longitudinal strain to determine optimal timing for surgery in primary mitral regurgitation: A systematic review

BACKGROUND

Primary mitral regurgitation (PMR) results in adverse remodeling changes and left ventricular (LV) dysfunction. Assessing LV function has prognostic value in predicting morbidity and mortality. Indications for surgery include parameters such as LV ejection fraction (LVEF) and systolic dimensions. Current guidelines are limited in identifying patients at optimal time for surgery. Impaired postoperative LVEF indicates poor prognostic outcomes and subsequent heart failure. Global longitudinal strain (GLS) via speckle tracking echocardiography (STE) presents as a promising parameter to detect subclinical dysfunction in asymptomatic patients.

METHODS

Following PRISMA guidelines, a literature search was conducted with Cochrane Library, PudMed, SCOPUS, and Web of Science. Key MeSH terms included "mitral regurgitation," "mitral valve insufficiency," "global longitudinal strain," "deformation," "LV-GLS," and "GLS." Inclusion criteria included (1) patients with severe PMR, (2) mixed population of symptomatic and asymptomatic patients, (3) standardized methods in assessing LV systolic function using 2D-STE, (4) valve repair or replacement surgery, and (5) patient outcomes measured after surgery. Search returned 234 papers, 12 of which met the inclusion criteria and were subsequently reviewed.

RESULTS

Baseline GLS is an independent predictor of postoperative outcomes, ranging from -17.9 to -21.7% GLS. A significant negative correlation was observed between preoperative GLS and postoperative LVEF. Impaired baseline GLS was associated with higher mortality rates. Better long-term survival rates were seen in patients who underwent early surgery.

CONCLUSION

GLS shows sensitivity in predicting long-term postoperative outcomes. Further analysis is required to determine preoperative GLS threshold to identify asymptomatic patients at the optimal time for mitral valve surgery.

Novelties in 3D Transthoracic Echocardiography

Cardiovascular imaging is developing at a rapid pace and the newer modalities, in particular three-dimensional echocardiography, allow better analysis of heart structures. Identifying valve lesions and grading their severity represents crucial information and nowadays is strengthened by the introduction of new software, such as transillumination, which provide detailed morphology descriptions. Chambers quantification has never been so rapid and accurate: machine learning algorithms generate automated volume measurements, including left ventricular systolic and diastolic function, which is extremely important for clinical decisions. This review provides an overview of the latest innovations in the echocardiography field, and is helpful by providing a better insight into heart diseases.

Ventricular systolic dysfunction with and without altered myocardial contractility: Clinical value of echocardiography for diagnosis and therapeutic decision-making

The inability of one of the two or both ventricles to contract normally and expel sufficient blood to meet the functional demands of the body results from a complex interplay between intrinsic abnormalities and extracardiac factors that limit ventricular pump function and is a major cause for heart failure (HF). Even if impaired myocardial contractile function was the primary cause for ventricular dysfunction, with the progression of systolic dysfunction, additionally developed diastolic dysfunction can also contribute to the severity of HF. Although at the first sight, the diagnosis of systolic HF appears quite easy because it is usually defined by reduction of the ejection fraction (EF), in reality this issue is far more complex because ventricular pumping performance depends not only on myocardial contractility, but also largely on loading conditions (preload and afterload), being also influenced by valvular function, ventricular interdependence, pericardial constraint, synchrony of ventricular contrac-tion and heart rhythm. Conventional echocardiography (ECHO) combined with new imaging techniques such as tissue Doppler and tissue tracking can detect early subclinical alteration of ventricular systolic function. However, no single ECHO parameter reveals alone the whole picture of systolic dysfunction. Multiparametric ECHO evaluation and the use of integrative approaches using ECHO-parameter combinations which include also the ventricular loading conditions appeared particularly useful especially for differentiation between primary (myocardial damage-induced) and secondary (hemodynamic overload-induced) systolic dysfunction. This review summarizes the available evidence on the usefulness and limitations of comprehensive evaluation of LV and RV systolic function by using all the currently available ECHO techniques.

Global Longitudinal Strain Predicts Survival and Left Ventricular Function After Mitral Valve Surgery: A Meta-analysis

The timing for surgical treatment in patients with primary organic severe mitral valve regurgitation and preserved left ventricular ejection fraction (LVEF) systolic is a challenge since it depends upon LV end systolic dimension and LVEF which may be late markers of LV dysfunction. Echocardiography is the most important tool in the diagnosis of mechanisms, etiology, severity, and hemodynamic consequences of mitral regurgitation. The global longitudinal strain (GLS), a new and sensitive method for the detection of LV dysfunction, might be a useful method for the evaluation of preclinical systolic dysfunction. Nevertheless, its role for predicting postoperative outcomes is not well established. A meta-analysis was performed to address the role of GLS in patients with severe mitral regurgitation and preserved LVEF who underwent mitral surgery. We included studies that compared outcomes according to preoperative GLS in regard to survival and postoperative LV function. We included 2358 patients enrolled in 8 studies. Patients with reduced GLS% had worse long term survival after mitral valve surgery (hazard ratio = 1.13, 95% confidence interval [CI]: 1.02-1.26). Patients with preoperatively reduced GLS% had lower LVEF after surgery (mean difference [MD] = -5.06%, 95% CI: -8.97-1.16%) and additionally, patients who presented postoperative LVEF dysfunction had worse preoperative GLS (MD = 4.33, 95% CI: 3.89-4.76). In patients with primary mitral regurgitation, preoperative GLS is a predictor for long term survival and postoperative LVEF. It is a useful parameter to be included when considering early surgery in patients with severe mitral regurgitation and normal LVEF.

New Myocardial Deformation by 2D Multi-layer Speckle-Tracking Analysis in Healthy Patients: Normal Reference Values and Their Physiologic Determinants

There are limited data regarding intrinsic changes of the left (LV) and right ventricular (RV) deformation assessed layer-by-layer. We designed a prospective multi-centric study, using a new multi-layer 2D-speckle-tracking-echo (MSTE). We investigated the impact of different physiologic parameters on layer-specific LV/RV myocardial deformation and synchrony, in a large group of healty subjects. 151 subjects were feasible for MSTE, divided in 4 groups: <40 yrs, 41 to 50 yrs, 51 to 60, and >61 yrs. We found a significant higher LV dyssynchrony index with age. In all groups, an endo-epicardial gradient was present in longitudinal LV/RV and circumferential deformation, with higher values in endocardial layer (p<0.001). There were no differences in deformation with age in all layers. We provided normal reference values for a new index of LV dyssynchrony, and also for RV longitudinal, LV circumferential and longitudinal layer-specific deformation, which can be further used when assessing subclinical dysfunction in myocardial diseases.

Global longitudinal strain to predict left ventricular dysfunction in asymptomatic patients with severe mitral valve regurgitation: literature review

The optimal treatment strategy for asymptomatic patients with severe mitral valve regurgitation (MR) and preserved left ventricular (LV) function is challenging. This manuscript reviews the available literature on the value of left ventricular global longitudinal strain (LV-GLS) in predicting LV dysfunction after mitral valve surgery in these patients and discusses its current place in the treatment strategy. Studies were identified from Cochrane Library, SCOPUS, PubMed and Web of Science up to February 2018. The domain used was MR. The determinant was LV-GLS; other methods of deformation imaging were excluded. The examined outcome was LV dysfunction after surgery. A total of 144 articles were retrieved, of which 11 publications met the inclusion criteria, including a total of 2415 patients. Ten studies showed a significant correlation between preoperative LV-GLS and LV dysfunction postoperatively; one study reported a negative correlation. These studies suggest that LV-GLS is a predictor of LV dysfunction after surgery in asymptomatic patients with chronic MR. Hence, incorporation of LV-GLS for clinical decision-making in these patients might be of additional value. Further research is needed to confirm the role of LV-GLS in postoperative patients, and additionally in asymptomatic MR patients during a 'watchful waiting' strategy.

A Comparison of Left- and Right-Sided Strain Software for the Assessment of Intraoperative Right Ventricular Function

OBJECTIVE

To compare intraoperative right ventricular (RV) strain measurements made with left ventricular (LV) strain software commonly found on the echocardiography machine (Philips QLAB chamber motion quantification, version 10.7, Philips, Amsterdam, The Netherlands), with offline analysis using the dedicated RV strain software (EchoInsight, version 2.2.6.2230, Epsilon Imaging, Ann Arbor, MI).

DESIGN

Prospective, nonrandomized, observational study.

SETTING

Single tertiary level, university-affiliated hospital.

PARTICIPANTS

The study comprised 48 patients undergoing transesophageal echocardiography for cardiac or noncardiac surgery.

INTERVENTIONS

Two-dimensional (2D) and 3-dimensional (3D) images of the right ventricle were obtained. Intraoperative 2D images were analyzed in real time for RV free wall strain (FWS) and global longitudinal strain (GLS) using QLAB chamber motion quantification (CMQ) LV strain software on the echocardiography machine. Two dimensional images were then analyzed offline to determine the RV FWS and GLS using EchoInsight RV-specific strain software. Three-dimensional images were then analyzed offline to detemine the 3D RV ejection fraction (3D RV EF) using TomTec 4D RV function (Unterschleissheim, Germany). Spearman's correlation and Bland-Altman analyses were used to characterize the relationship between RV strain measurements. Both types of strain measurements were compared to a reference standard of 3D RV EF.

MEASUREMENTS AND MAIN RESULTS

Intraoperative RV strain measurements using LV-specific strain software correlated with offline RV strain measurements using the RV-specific strain software (FWS rho = 0.85; GLS rho = 0.81). The bias and limits of agreement were 0.75% (- 6.66 to 8.17) for FWS and -4.53% (-11.55 to 2.50) for GLS. The sensitivity and specificity for RV dysfunction for the intraoperative LV-specific software were 94% (95% confidence interval [CI] 73-100) and 70% (95% CI 51-85), respectively, for RV FWS and 94% (95% CI 73-100) and 67% (95% CI 47-83), respectively, for RV GLS. The sensitivity and specificity for RV dysfunction for the offline RV-specific software were 89% (95% CI 65-99) and 73% (95% CI 54-88), respectively, for RV FWS and 94% (95% CI 73-100) and 30% (95% CI 15-49), respectively, for RV GLS.

CONCLUSION

Intraoperative RV strain measurements using LV-specific strain software commonly available on the echocardiography machine (QLAB CMQ) correlate with offline RV strain measurements using RV-specific strain software (EchoInsight). The bias and limits of agreement for these left- and right-sided strain software suggest that these 2 measures of RV function cannot be used interchangeably. Both, however, were sensitive measures of RV dysfunction and therefore are likely clinically relevant.

New Definition Criteria of Myocardial Dysfunction in Patients with Liver Cirrhosis: A Speckle Tracking and Tissue Doppler Imaging Study

There are no clear recommendations regarding cirrhotic cardiomyopathy (CC) evaluation in patients with pre-transplant liver cirrhosis. The roles of new methods, tissue Doppler imaging (TDI) and speckle tracking echocardiography (STE) in the diagnosis and prognosis of cirrhotic cardiomyopathy remain controversial. We investigated the utility of TDI/STE parameters in cirrhotic cardiomyopathy diagnosis and also in predicting mortality in patients with liver cirrhosis. Left/right ventricular function was studied using conventional TDI (velocities) and STE (strain/strain rate). We assessed left ventricular diastolic dysfunction, graded into four new classes (I/Ia/II/III). Serum NTproBNP (N-terminal prohormone of brain natriuretic peptide), troponin I, β-crosslaps, QTc interval, arterial compliance and endothelial function were measured. Liver-specific scores (Child-Pugh, MELD, MELDNa) were computed. There was a 1-y follow-up visit to determine mortality. We observed resting biventricular diastolic myocardial dysfunction, not presently included in the definition of cirrhotic cardiomyopathy. We provided an improved characterization of cardiac dysfunction in patients with liver cirrhosis. This might change the current definition. However, the utility of STE/TDI parameters in predicting long-term mortality in patients with liver cirrhosis remains controversial.

Interactions between mitral valve and left ventricle analysed by 2D speckle tracking in patients with mitral valve prolapse: one more piece to the puzzle

Aims

Two-dimensional echocardiography often reveals abnormal left ventricle (LV) lateral wall kinetics in patients presenting with mitral valve prolapse (MVP). However, relations between MVP and LV deformation are not clearly established. The aim of this study was to assess and quantify mitral valve chordae, leaflets, and LV myocardial interactions using speckle tracking echocardiography (STE).

Methods and results

Using STE-derived longitudinal strain curves, LV peak longitudinal strain (PLS, %), post-systolic index (PSI), and pre-stretch index (PST) were analysed in 100 patients with MVP and normal LV ejection fraction. Global, regional, and segmental values were compared according to mitral regurgitation severity and MVP location. Twenty healthy subjects served as control patients. There was no significant difference among control and MVP group for global and regional PLS (-23.7 ± 3.2 vs. -23.1 ± 2.2). In contrast, patients with MVP had significantly higher values of global PST (3.2 ± 4.1 vs. 1.3 ± 1.2; P = 0.01) and global PSI (3.2 ± 0.4 vs. 1.7 ± 1.1; P = 0.05) compared with controls, located mainly in the lateral wall and basal segments. Both anterior and posterior MVPs were responsible for PSI in basal inferior segments and PST in anterior ones. Mid-wall segmental deformation pattern changes were mainly observed at the level of the segments adjacent to the papillary muscle.

Conclusion

This study supports the hypothesis that pathological early-systolic shortening and late systolic, post-systolic deformation are attributed to an increased interaction between wall deformation and mitral valve events in patients with MVP. STE is a useful tool in the assessment of interplays between MV leaflets and myocardium and helps to demonstrate changes in temporal pattern of myocardial deformation.

Longitudinal assessment of myocardial function in childhood chronic kidney disease, during dialysis, and following kidney transplantation

BACKGROUND

Childhood chronic kidney disease (CKD) and dialysis are associated with increased long-term cardiovascular risk. We examined subclinical alterations in myocardial mechanics longitudinally in children with CKD, during dialysis, and following renal transplantation.

METHODS

Forty-eight children with CKD (stage III or higher) who received kidney transplants from 2008 to 2014 were included in a retrospective study and compared to 192 age- and sex-matched healthy children. Measurements of cardiac systolic and diastolic function were performed, and global longitudinal strain (GLS) and circumferential strain (GCS) were measured by speckle-tracking echocardiography at CKD, during dialysis, and 1 year following kidney transplantation. Mixed-effects modeling examined changes in GLS and GCS over different disease stages.

RESULTS

Children with CKD had a mean age of 10 ± 5 years and 67% were male. Eighteen children received preemptive transplantation. Children with CKD had increased left ventricular mass, lower GLS, and impaired diastolic function (lower E/A ratio and E' velocities) than healthy children. Changes in left ventricular diastolic parameters persisted during dialysis and after renal transplantation. Dialysis was associated with reduced GLS compared to CKD (β = 1.6, 95% confidence interval 0.2-3.0); however, this was not significant after adjustment for systolic blood pressure and CKD duration. Post-transplantation GLS levels were similar to those at CKD assessment. GCS was unchanged during dialysis but significantly improved following transplantation.

CONCLUSIONS

There are differences in diastolic parameters in childhood CKD that persist during dialysis and after transplantation. Systolic parameters are preserved, with significant improvement in systolic myocardial deformation following transplantation. The impact of persistent diastolic changes on long-term outcomes requires further investigation.

Early Left and Right Ventricular Response to Aortic Valve Replacement

BACKGROUND

The immediate effect of aortic valve replacement (AVR) for aortic stenosis on perioperative myocardial function is unclear. Left ventricular (LV) function may be impaired by cardioplegia-induced myocardial arrest and ischemia-reperfusion injury, especially in patients with LV hypertrophy. Alternatively, LV function may improve when afterload is reduced after AVR. The right ventricle (RV), however, experiences cardioplegic arrest without benefiting from improved loading conditions. Which of these effects on myocardial function dominate in patients undergoing AVR for aortic stenosis has not been thoroughly explored. Our primary objective is thus to characterize the effect of intraoperative events on LV function during AVR using echocardiographic measures of myocardial deformation. Second, we evaluated RV function.

METHODS

In this supplementary analysis of 100 patients enrolled in a clinical trial (NCT01187329), 97 patients underwent AVR for aortic stenosis. Of these patients, 95 had a standardized intraoperative transesophageal echocardiographic examination of systolic and diastolic function performed before surgical incision and repeated after chest closure. Echocardiographic images were analyzed off-line for global longitudinal myocardial strain and strain rate using 2D speckle-tracking echocardiography. Myocardial deformation assessed at the beginning of surgery was compared with the end of surgery using paired t tests corrected for multiple comparisons.

RESULTS

LV volumes and arterial blood pressure decreased, and heart rate increased at the end of surgery. Echocardiographic images were acceptable for analysis in 72 patients for LV strain, 67 for LV strain rate, and 54 for RV strain and strain rate. In 72 patients with LV strain images, 9 patients required epinephrine, 22 required norepinephrine, and 2 required both at the end of surgery. LV strain did not change at the end of surgery compared with the beginning of surgery (difference: 0.7 [97.6% confidence interval, -0.2 to 1.5]%; P = 0.07), whereas LV systolic strain rate improved (became more negative) (-0.3 [-0.4 to -0.2] s; P < 0.001). In contrast, RV systolic strain worsened (became less negative) at the end of surgery (difference: 4.6 [3.1 to 6.0]%; P < 0.001) although RV systolic strain rate was unchanged (0.0 [97.6% confidence interval, -0.1 to 0.1]; P = 0.83).

CONCLUSIONS

LV function improved after replacement of a stenotic aortic valve demonstrated by improved longitudinal strain rate. In contrast, RV function, assessed by longitudinal strain, was reduced.

Incremental Value of Two Dimensional Speckle Tracking Echocardiography in the Functional Assessment and Characterization of Subclinical Left Ventricular Dysfunction

Subclinical left ventricular (LV) dysfunction refers to subtle abnormalities in LV function which typically precede a reduction in the left ventricular ejection fraction (LVEF). The assessment of myocardial function using LVEF, a radial metric of systolic function, is subject to load dependence, intra-observer and inter-observer variability. Reductions in LVEF typically manifest late in the disease process thus compromising the ability to intervene before irreversible impairment of systolic performance sets in. 2-Dimensional speckle tracking echocardiography (2D-STE), a novel strain imaging modality has shown promise as a sensitive indicator of myocardial contractility. It arms the clinician with a powerful and practical tool to rapidly quantify cardiac mechanics, circumventing several inherent limitations of conventional echocardiography. This article highlights the incremental utility of 2D-STE in the detection of subclinical LV dysfunction.

Synergistic Utility of Brain Natriuretic Peptide and Left Ventricular Global Longitudinal Strain in Asymptomatic Patients With Significant Primary Mitral Regurgitation and Preserved Systolic Function Undergoing Mitral Valve Surgery

Background—

In asymptomatic patients with ≥3+ mitral regurgitation and preserved left ventricular (LV) ejection fraction who underwent mitral valve surgery, we sought to discover whether baseline LV global longitudinal strain (LV-GLS) and brain natriuretic peptide provided incremental prognostic utility.

Methods and Results—

Four hundred and forty-eight asymptomatic patients (61±12 years and 69% men) with ≥3+ primary mitral regurgitation and preserved left ventricular ejection fraction, who underwent mitral valve surgery (92% repair) at our center between 2005 and 2008, were studied. Baseline clinical and echocardiographic data (including LV-GLS using Velocity Vector Imaging, Siemens, PA) were recorded. The Society of Thoracic Surgeons score was calculated. The primary outcome was death. Mean Society of Thoracic Surgeons score, left ventricular ejection fraction, mitral effective regurgitant orifice, indexed LV end-diastolic volume, and right ventricular systolic pressure were 4±1%, 62±3%, 0.55±0.2 cm 2 , 58±13 cc/m 2 , and 37±15 mm Hg, respectively. Forty-five percent of patients had flail. Median log-transformed BNP and LV-GLS were 4.04 (absolute brain natriuretic peptide: 60 pg/dL) and −20.7%. At 7.7±2 years, death occurred in 41 patients (9%; 0% at 30 days). On Cox analysis, a higher Society of Thoracic Surgeons score (hazard ratio 1.55), higher baseline right ventricular systolic pressure (hazard ratio 1.11), more abnormal LV-GLS (hazard ratio 1.17), and higher median log-transformed BNP (hazard ratio 2.26) were associated with worse longer-term survival (all P <0.01). Addition of LV-GLS and median log-transformed BNP to a clinical model (Society of Thoracic Surgeons score and baseline right ventricular systolic pressure) provided incremental prognostic utility (χ 2 for longer-term mortality increased from 31–47 to 61; P <0.001).

Conclusions—

In asymptomatic patients with significant primary mitral regurgitation and preserved left ventricular ejection fraction who underwent mitral valve surgery, brain natriuretic peptide and LV-GLS provided synergistic risk stratification, independent of established factors.

Perioperative assessment of myocardial deformation

Evaluation of left ventricular performance improves risk assessment and guides anesthetic decisions. However, the most common echocardiographic measure of myocardial function, the left ventricular ejection fraction (LVEF), has important limitations. LVEF is limited by subjective interpretation that reduces accuracy and reproducibility, and LVEF assesses global function without characterizing regional myocardial abnormalities. An alternative objective echocardiographic measure of myocardial function is thus needed. Myocardial deformation analysis, which performs quantitative assessment of global and regional myocardial function, may be useful for perioperative care of surgical patients. Myocardial deformation analysis evaluates left ventricular mechanics by quantifying strain and strain rate. Strain describes percent change in myocardial length in the longitudinal (from base to apex) and circumferential (encircling the short-axis of the ventricle) direction and change in thickness in the radial direction. Segmental strain describes regional myocardial function. Strain is a negative number when the ventricle shortens longitudinally or circumferentially and is positive with radial thickening. Reference values for normal longitudinal strain from a recent meta-analysis by using transthoracic echocardiography are (mean ± SD) -19.7% ± 0.4%, while radial and circumferential strain are 47.3% ± 1.9% and -23.3% ± 0.7%, respectively. The speed of myocardial deformation is also important and is characterized by strain rate. Longitudinal systolic strain rate in healthy subjects averages -1.10 ± 0.16 s. Assessment of myocardial deformation requires consideration of both strain (change in deformation), which correlates with LVEF, and strain rate (speed of deformation), which correlates with rate of rise of left ventricular pressure (dP/dt). Myocardial deformation analysis also evaluates ventricular relaxation, twist, and untwist, providing new and noninvasive methods to assess components of myocardial systolic and diastolic function. Myocardial deformation analysis is based on either Doppler or a non-Doppler technique, called speckle-tracking echocardiography. Myocardial deformation analysis provides quantitative measures of global and regional myocardial function for use in the perioperative care of the surgical patient. For example, coronary graft occlusion after coronary artery bypass grafting is detected by an acute reduction in strain in the affected coronary artery territory. In addition, assessment of left ventricular mechanics detects underlying myocardial pathology before abnormalities become apparent on conventional echocardiography. Certainly, patients with aortic regurgitation demonstrate reduced longitudinal strain before reduction in LVEF occurs, which allows detection of subclinical left ventricular dysfunction and predicts increased risk for heart failure and impaired myocardial function after surgical repair. In this review, we describe the principles, techniques, and clinical application of myocardial deformation analysis.

Myocardial deformation and rotational profiles in mitral valve prolapse

We studied whether evaluation of overall left ventricular (LV) and left atrial (LA) mechanics would be useful to detect subclinical dysfunction in patients with mitral valve prolapse (MVP), mitral regurgitation (MR), and normal LV ejection fraction (EF). Fifty consecutive patients (27 men, mean age 61 ± 19 years) with MVP, MR, and normal systolic function (LVEF ≥60%) were prospectively enrolled and compared with 40 age- and gender-matched healthy subjects (22 men, mean age: 59 ± 16 years). At baseline, 2-dimensional and color-flow Doppler transthoracic echocardiography were performed for MR quantification and analysis of left-chambers mechanics. Patients were divided into groups by severity of MR: mild (n = 14), moderate (n = 19), and severe (n = 17). Left ventricular dimensions, volume and mass, and LA area and volume indices were significantly increased in patients with moderate and severe MR compared with control subjects. Circumferential strain, basal/apical rotations, and twist were significantly enhanced in patients with moderate MR compared with controls; with the exception of basal rotation, they decreased in those with severe MR. Furthermore, LA strain and untwisting rate were progressively and significantly reduced from normal subjects to patients with severe MR. Effective regurgitant orifice area and MR vena contracta were significantly related to most systolic and diastolic function parameters and LA volume as well as LA strain and LV untwisting rate in all patients. In conclusion, cardiac mechanics indices, particularly LA deformation and LV rotational parameters, could help unmask incipient myocardial dysfunction in patients with MVP, especially in those with severe MR and yet normal LVEF.

Heart involvement in rheumatoid arthritis: multimodality imaging and the emerging role of cardiac magnetic resonance

OBJECTIVES

Patients with rheumatoid arthritis (RA) exhibit a high risk of cardiovascular disease (CVD). CVD in RA can present in many guises, commonly detected at a subclinical level only.

METHODS

Modern imaging modalities that allow the noninvasive assessment of myocardial performance and are able to identify cardiac abnormalities in early asymptomatic stages may be useful tools in terms of screening, diagnostic evaluation, and risk stratification in RA.

RESULTS

The currently used imaging techniques are echocardiography, single-photon emission computed tomography (SPECT), and cardiac magnetic resonance (CMR). Between them, echocardiography provides information about cardiac function, valves, and perfusion; SPECT provides information about myocardial perfusion and carries a high amount of radiation; and CMR-the most promising imaging modality-evaluates myocardial function, inflammation, microvascular dysfunction, valvular disease, perfusion, and presence of scar. Depending on availability, expertise, and clinical queries, "right technique should be applied for the right patient at the right time."

CONCLUSIONS

In this review, we present a short overview of CVD in RA focusing on the clinical implication of multimodality imaging and mainly on the evolving role of CMR in identifying high-risk patients who could benefit from prevention strategies and early specific treatment targeting the heart. Advantages and disadvantages of each imaging technique in the evaluation of RA are discussed.