Quantitative Echocardiography Research Articles

Mental stress-induced myocardial ischemia detected by global longitudinal strain and quantitative myocardial contrast echocardiography in women with nonobstructive coronary artery disease

BackgroundThe utility of radionuclide myocardial perfusion imaging including positron emission tomography (PET) for diagnosing mental stress-induced myocardial ischemia (MSIMI) is clinically restricted. This study aims to assess the diagnostic performance of novel echocardiographic techniques, including automated strain and quantitative myocardial contrast echocardiography (MCE) with dedicated software and deep neural network (DNN) model, for MSIMI detection. The secondary objective was to explore the correlation between changes in myocardial blood flow (MBF) and MSIMI. Methods72 female patients aged 18 to 75 with angina and nonobstructive coronary artery disease (ANOCA), and 23 healthy controls were prospectively recruited. Both echocardiography with contrast agent and PET imaging were performed during structured mental stress testing. MSIMI was defined as a summed difference score ≥3 on PET. Echocardiographic parameters including left ventricular global longitudinal strain (LVGLS), β and A×β were obtained, and their trends during mental stress testing were observed. ΔGLS, β reserve and A×β reserve were respectively calculated. Results32 ANOCA patients (44%) and 1 control (4%) were diagnosed with MSIMI (P<0.01). For ANOCA patients with MSIMI, LVGLS, β and A×β declined to varied extent during mental stress testing compared to those without MSIMI and the controls (P<0.05). Bland-Altman plots demonstrated good consistency between β reserve and A×β reserve output by the DNN model and iMCE software. Receiver operating characteristic (ROC) curve analyses showed that ΔGLS, β reserve and A×β reserve demonstrated favorable ability to predict MSIMI, especially the combination of A×β reserve using iMCE analysis and ΔGLS (area under the curve [AUC] 0.94, sensitivity 83%, specificity 97%). ConclusionsNovel technologies in echocardiography exhibit the potential to be a clinical alternative to cardiac PET for effectively detecting MSIMI. Attenuated MBF response during structured mental stress testing was correlated with MSIMI, providing a reasonable explanation for the chest discomfort persisting in ANOCA women.

Curcumin simultaneously improves mitochondrial dynamics and myocardial cell bioenergy after sepsis via the SIRT1-DRP1/PGC-1α pathway

Septic cardiomyopathy (SCM) is associated with an imbalance in mitochondrial quality and high mortality rates, with no effective treatment developed to date. Curcumin provides antioxidant, anti-inflammatory, cardiovascular, and mitochondrial protection. However, curcumin has not been confirmed to improve cardiac dysfunction in sepsis. We hypothesized that curcumin can reduce abnormal inflammatory responses by improving mitochondrial function as a novel mechanism to improve SCM. To explore this hypothesis, we used an in vivo male C57BL/6 mouse sepsis model and an in vitro model of lipopolysaccharide-stimulated HL-1 cells. The effects of curcumin on sepsis-induced cardiac dysfunction, inflammatory responses, and mitochondrial quality of cardiac cells were observed using quantitative polymerase chain reaction, western blotting, echocardiography, and transmission electron microscopy. Curcumin activated sirtuin 1 (SIRT1); increased expression of the mitochondrial biogenesis-related genes Pgc1α, Tfam, and Nrf2; reduced dynamin-related protein 1 translocation from the cytoplasm to mitochondria; and restored the mitochondrial morphology and function in cardiac cells. Accordingly, curcumin protected heart function after septic shock and alleviated the effects of SCM. SIRT1 knockdown reversed the protective effects of curcumin on mitochondria. Therefore, curcumin promotes mitochondrial biogenesis and inhibits mitochondrial fragmentation by activating SIRT1, thereby improving the mitochondrial quality and reducing oxidative stress in cardiomyocytes and sepsis-induced cardiac dysfunction. These findings provide new evidence supporting the use of curcumin to treat SCM.

Tricuspid Regurgitation in Acute Heart Failure: Predicting Outcome Using Novel Quantitative Echocardiography Techniques.

Background: The prognostic impact of tricuspid regurgitation (TR) in acute heart failure (AHF) remains uncertain. Methods: We retrospectively assessed 418 consecutive AHF patients who underwent comprehensive echocardiographic assessment within 24 h of study recruitment. TR was quantitatively assessed with 3 guideline-directed measures: regurgitant volumes (RgVol), effective regurgitant orifice area (ERO) and vena contracta (VC) diameter. Disproportionate TR was assessed by the ratio of the VC diameter to the tricuspid annulus diameter (VC/TA) ≥ 0.24. Results: The prevalence of significant (i.e., >mild) TR differed when various standard assessment parameters were applied to quantification: RgVol 50.3% (173/344), ERO 75.6% (260/344) and VC diameter 94.6% (335/354). None were able to delineate those at excess risk of all-cause 2-year mortality using guideline-directed cut-offs of mild, moderate and severe TR. Using a cut-off of VC/TA ≥ 0.24, we identified that 36.9% (130/352) had “disproportionate” TR. Disproportionate TR was associated with an excess risk of mortality at 2 years compared to proportionate TR; HR 1.48 (95% CI 1.06−2.06 [p = 0.02]) which was not significant on multivariate assessment (p = 0.94). Conclusions: TR was not associated with outcome in AHF using guideline measures. A new assessment of “Disproportionate” TR carries a higher risk than proportionate TR but was not related to outcome based on multivariate analysis. Further research is needed to quantify TR more effectively to identify cut-offs for future guidelines and disproportionate TR may be an important part of Heart Failure 2.0.

Measurements of exercise gas exchange during quantitative stress echocardiography in patient with coronary micovascular disease: a case report

Measurements of exercise gas exchange during quantitative stress echocardiography in patient with coronary micovascular disease: a case report

Measurement of exercise gas exchange during quantitative stress echocardiography might improve differentiation of myocardial ischemia from fibrosis

Measurement of exercise gas exchange during quantitative stress echocardiography might improve differentiation of myocardial ischemia from fibrosis

Comparative analysis of instantaneous wave-free ratio and quantitative real-time myocardial contrast echocardiography for the assessment of myocardial perfusion.

The field of coronary artery physiology is developing rapidly and changing the practice of interventional cardiology. A new functional evaluation technique using the instantaneous wave-free ratio (iFR) has become an alternative to fractional flow reserve. Future research studies need to determine whether physiological indicators play a role in evaluating myocardial perfusion in the catheter room. Thirty-eight patients scheduled for coronary angiography and iFR evaluation underwent a real-time myocardial contrast echocardiography (RT-MCE) examination at rest. The myocardial perfusion parameters (A, β, and A × β) on the myocardial perfusion curve were quantitatively analyzed using Q-Lab software. Coronary angiography and iFR assessment were completed within 1 week after the RT-MCE examination in all patients. Correlation analysis was used to identify iFR- and MCE-related indicators. The sensitivity and specificity of iFR in the quantitative detection of coronary microcirculation were obtained. The correlation coefficients between iFR and A, β, and A × β were 0.81, 0.66, and 0.82, respectively. The cut-off value for iFR was 0.85 for microvascular ischemia detection, while the sensitivity and specificity for the diagnosis of myocardial perfusion were 90.7 and 89.9%, respectively. The receiver operating characteristic (ROC) curve area for iFR was 0.946 in the segments related to myocardial blood flow. The iFR is an effective tool for detecting myocardial microcirculation perfusion, with satisfactory diagnostic performance and a demonstrated role in physiological indices used for the perfusion assessment.

L-2-Hydroxyglutarate Protects Against Cardiac Injury via Metabolic Remodeling.

L-2-hydroxyglutarate (L2HG) couples mitochondrial and cytoplasmic energy metabolism to support cellular redox homeostasis. Under oxygen-limiting conditions, mammalian cells generate L2HG to counteract the adverse effects of reductive stress induced by hypoxia. Very little is known, however, about whether and how L2HG provides tissue protection from redox stress during low-flow ischemia (LFI) and ischemia-reperfusion injury. We examined the cardioprotective effects of L2HG accumulation against LFI and ischemia-reperfusion injury and its underlying mechanism using genetic mouse models. L2HG accumulation was induced by homozygous (L2HGDH [L-2-hydroxyglutarate dehydrogenase]-/-) or heterozygous (L2HGDH+/-) deletion of the L2HGDH gene in mice. Hearts isolated from these mice and their wild-type littermates (L2HGDH+/+) were subjected to baseline perfusion and 90-minute LFI or 30-minute no-flow ischemia followed by 60- or 120-minute reperfusion. Using [13C]- and [31P]-NMR (nuclear magnetic resonance) spectroscopy, high-performance liquid chromatography, reverse transcription quantitative reverse transcription polymerase chain reaction, ELISA, triphenyltetrazolium staining, colorimetric/fluorometric spectroscopy, and echocardiography, we found that L2HGDH deletion induces L2HG accumulation at baseline and under stress conditions with significant functional consequences. In response to LFI or ischemia-reperfusion, L2HG accumulation shifts glucose flux from glycolysis towards the pentose phosphate pathway. These key metabolic changes were accompanied by enhanced cellular reducing potential, increased elimination of reactive oxygen species, attenuated oxidative injury and myocardial infarction, preserved cellular energy state, and improved cardiac function in both L2HGDH-/- and L2HGDH+/- hearts compared with L2HGDH+/+ hearts under ischemic stress conditions. L2HGDH deletion-induced L2HG accumulation protects against myocardial injury during LFI and ischemia-reperfusion through a metabolic shift of glucose flux from glycolysis towards the pentose phosphate pathway. L2HG offers a novel mechanism for eliminating reactive oxygen species from myocardial tissue, mitigating redox stress, reducing myocardial infarct size, and preserving high-energy phosphates and cardiac function. Targeting L2HG levels through L2HGDH activity may serve as a new therapeutic strategy for cardiovascular diseases related to oxidative injury.

Quantitative Echocardiography Improves Resident Assessment of Left Ventricular Systolic Function.

The use of echocardiography to assess left ventricular ejection fraction (LVEF) is an important component of anesthesiology resident education; however, there is no consensus on the most effective method for teaching this skill set. This study investigates the impact and feasibility of teaching a quantitative LVEF assessment method to anesthesiology residents, compared with teaching visual estimation techniques. We included all anesthesiology residents rotating through cardiac anesthesia at our institution from August 2020 through March 2021. Participants completed a pretest to assess baseline ability to accurately estimate LVEF. All tests consisted of transthoracic echocardiography images with standard views from 10 patients. Participants were assigned to either a control group that received teaching on visual estimation of LVEF or an intervention group that was taught quantitative LVEF assessment with the Simpson biplane method of discs. After 4 weeks, all participants were administered a postteaching exam. A retention exam was administered an additional 4 weeks later. LVEF accuracy was measured as the absolute difference between their LVEF estimation and the reference value. Control and intervention groups performed similarly on the preteaching exam of LVEF estimation accuracy. Intervention-group residents demonstrated significantly improved accuracy in LVEF assessment on the postteaching exam (3.6% improvement in accuracy, confidence interval [CI], 1.23-5.97; P = .03) compared with the control group (0.60% improvement inaccuracy, CI, -1.77-2.97; P = .62). The observed improvement was not maintained through the retention exam.Conclusions: Addition of quantitative LVEF assessment to traditional teaching of visual LVEF estimation methods significantly improved the diagnostic accuracy of anesthesiology residents' left ventricular systolic function assessment.

Correlation between standard and adjusted echocardiographic quantitative methods for evaluating tricuspid regurgitation severity

Abstract Funding Acknowledgements Type of funding sources: None. Background Current guidelines advocate for a multi-parametric approach to echocardiographic quantitation of tricuspid regurgitation (TR). The primary quantitative measure of TR severity uses the proximal isovelocity surface area (PISA) method to calculate effective regurgitant orifice area (EROA) and regurgitant volume (RegVol). However, EROA-PISA may underestimate TR severity due to low flow and tethering of the tricuspid leaflets. Purpose The purpose of this study was to compare standard EROA-PISA quantitation of TR to alternative quantitative measures, including quantitative Doppler (EROA-Doppler), flow- and angle-corrected PISA method (EROA-Corrected), and three-dimensional vena contracta area (3D-VCA), in addition to the comparison of calculated RegVol-PISA, RegVol-Doppler, and RegVol-3DVCA. Methods Patients undergoing both transthoracic (TTE) and transesophageal (TEE) echocardiographic evaluation of TR severity for transcatheter treatment were included in this study. Patients were excluded if they had ≥ moderate aortic regurgitation. TTE measurements of EROA-PISA and RegVol-PISA were performed as per American Society of Echocardiography guidelines. EROA-Doppler was performed by quantifying RegVol-Doppler (diastolic stroke volume using biplane annular area, minus left ventricular outflow stroke volume) and deriving EROA. EROA-Corrected was calculated by adjusting for both aliasing velocity and leaflet angle as per published methods. 3D-VCA was measured on TEE performed within 14 days of TTE. Results Of 44 consecutive patients, the median age was 80 ± 9 years, 61% were female, and 89% had atrial fibrillation. Most patients (86%) had functional TR, 71% had a EROA-PISA ≥ 0.4 cm2. Table 1 shows the EROA and RegVol results for each method. EROA-PISA and RegVol-PISA were significantly lower than EROA-Doppler and RegVol-Doppler, as well as 3D-VCA and RegVol-3DVCA (all p &amp;lt; 0.0001). There was no significant difference between EROA-Doppler and 3D-VCA (p = 0.51), and RegVol-Doppler and RegVol-3DVCA (p = 0.66). EROA-Corrected reduced the absolute difference with EROA-Doppler (51% to 33%, p &amp;lt; 0.0001) and 3D-VCA (52% to 32%, p &amp;lt; 0.0001), but remained statistically lower than EROA-Doppler and 3D-VCA. Although EROA-PISA was strongly correlated to EROA-Doppler (r = 0.75, p &amp;lt; 0.0001) and 3D-VCA (r = 0.68, p &amp;lt; 0.0001), the correlation between EROA-Doppler and 3D-VCA was greatest (r = 0.77, p &amp;lt; 0.0001). Adjusting EROA-PISA for angle and flow demonstrated improved correlation to EROA-Doppler without affecting correlation to 3D-VCA (Figure 1). Conclusion Our study demonstrated that EROA-PISA significantly underestimates the severity of TR by EROA-Doppler and 3D-VCA. Although PISA correction methods reduced the underestimation, both EROA-Corrected and RegVol-Corrected remained significantly lower. EROA-Doppler and 3D-VCA and the calculated RegVol by each method, were closely correlated and not significantly different. Abstract Table 1 Abstract Figure 1

Tandem cardiovascular system modelling and machine learning for improved heart failure phenotyping.

Tandem cardiovascular system modelling and machine learning for improved heart failure phenotyping.

Abstract 12610: Larger Papillary Muscles and Thicker Chords Were Associated With Post-Operative Left Atrioventricular Valve Regurgitation in Partial AVSD, a Quantitative Three-Dimensional Echocardiography Study

Background: Up to 15% of patients with partial Atrioventricular Septal Defects ( p AVSD) require re-repair of the Left AtrioVentricular Valve (LAVV), with 30% having significant regurgitation. Previous qualitative studies suggest abnormalities in papillary muscles, shortened chordae and thick chords as features associated with LAVVR. We aim to quantitatively assess the sub valvar apparatus in pAVSD using three-Dimensional Echocardiography (3DE) for its association with LAVVR. Hypothesis: We hypothesize that larger papillary muscle and chordal thickness in patients with p AVSD is associated with post-operative LAVVR. Methods: This is a prospective study between 2006 and 2018, of pAVSD aged 0-18 years. All underwent 3DE under sedation using X7-2 probe on a Philips iE33 ultrasound system. Utilizing offline QLAB multi-planar reconstruction (v.10.8.5) we measured anterolateral (APM) and posteromedial papillary (PPM) muscle length; cross sectional area and circumference; chordal length and thickness in mid systole. We measured post-operative vena contracta and LAVV diameter in Apical 4 chamber using 2D color Doppler. Cohort was divided into patients with significant post-operative LAVVR vs. controls based on LAVV vena contracta/LAVV annulus ratio cut off &gt;0.25 (greatest one-third of cohort), LAVVR (n=22) and Controls (n=44). All variables are indexed to Body Surface Area, expressed as median [interquartile range] or mean (standard deviation). Results: LAVVR group were younger at initial surgery, had larger papillary muscles and thicker chords. Table 1 summarizes the variables for Control and LAVVR. Eighteen patients had LAVV re-repair, 14 (63%) were in LAVVR group and 4 (9%) in Controls. Median follow up was 1.5 years. Median time to re-repair was 1.3 years. Conclusion: p AVSD patients with a greater risk of post-operative LAVVR and subsequently re-repair were younger at first repair and had larger papillary muscles length, circumference and thicker chords.

Plasma Lipidomic Patterns in Patients with Symptomatic Coronary Microvascular Dysfunction.

Coronary microvascular dysfunction (MVD) is a syndrome of abnormal regulation of vascular tone, particularly during increased metabolic demand. While there are several risk factors for MVD, some of which are similar to those for coronary artery disease (CAD), the cause of MVD is not understood. We hypothesized that MVD in symptomatic non-elderly subjects would be characterized by specific lipidomic profiles. Subjects (n = 20) aged 35–60 years and referred for computed tomography coronary angiography (CTA) for chest pain but who lacked obstructive CAD (>50% stenosis), underwent quantitative regadenoson stress-rest myocardial contrast echocardiography (MCE) perfusion imaging for MVD assessment. The presence of MVD defined by kinetic analysis of MCE data was correlated with lipidomic profiles in plasma measured by liquid chromatography and high-resolution mass spectrometry. Nine of twenty subjects had evidence of MVD, defined by reduced hyperemic perfusion versus other subjects (beta-value 1.62 ± 0.44 vs. 2.63 ± 0.99 s−1, p = 0.009). Neither the presence of high-risk but non-obstructive CAD on CTA, nor CAD risk factors were different for those with versus without MVD. Lipidomic analysis revealed that patients with MVD had lower concentrations of long-carbon chain triacylglycerols and diacylglycerols, and higher concentrations of short-chain triacylglycerols. The diacylglycerol containing stearic and linoleic acid classified all participants correctly. We conclude that specific lipidomic plasma profiles occur in MVD involving saturated long-chain fatty acid-containing acylglycerols that are distinctly different from those in non-obstructive CAD. These patterns could be used to better characterize the pathobiology and potential treatments for this condition.

Hemodynamic optimization for neonates with neonatal encephalopathy caused by a hypoxic ischemic event: Physiological and therapeutic considerations

Neonatal encephalopathy due to a hypoxic-ischemic event is commonly associated with cardiac dysfunction and acute pulmonary hypertension; both therapeutic hypothermia and rewarming modify loading conditions and blood flow. The pathophysiological contributors to disease are complex with a high degree of clinical overlap and traditional bedside measures used to assess circulatory adequacy have multiple confounders. Comprehensive, quantitative echocardiography may be used to delineate the relative contribution of lung parenchymal, pulmonary vascular, and cardiac disease to hypotension and/or hypoxemic respiratory failure. In this review, we provide a detailed overview of the contributors to hemodynamic instability following perinatal hypoxic-ischemic injury. Our proposed approach to therapy focuses on physiopathological considerations with interventions individualized to this potentially complex condition and considers the pharmacological idiosyncrasies, which may occur among neonates with NE presenting with multiorgan dysfunction while undergoing therapeutic hypothermia.

Pseudoexfoliation syndrome: Are the eyes the mirror of the heart?

Pseudoexfoliation syndrome (PEX) is a disease characterized by the accumulation of fibrillary material in the extracellular matrix in the eye and many tissues. Myocardial involvement occurs as in other storage diseases. Speckle tracking echocardiography is a quantitative echocardiography modality that enables the detection of subclinical changes that cannot be detected by standard echocardiographic evaluation. In this study, we aimed to evaluate potential subclinical myocardial dysfunction in PEX patients by speckle tracking echocardiography. The study group consisting of 29 cardiac asymptomatic pseudoexfoliation syndromes and 30 healthy volunteers were included in this case-control cross-sectional study. Detailed echocardiographic evaluations and strain analyses of all participants were performed. Concerning standard echocardiographic parameters, there was only a marginally significant difference between the two groups in the e' mean wave, and it was lower in the PEX group than the control group (0.07±0.03, 0.10±0.08, respectively, P=.06). However, in strain echocardiography, the global longitudinal strain (GLS) value was observed to be significantly lower in the PEX group than the control group (-17.02±2.02, -19.29±2.26, respectively P<.001). GLS was observed to be an independent predictor in the multivariable logistic regression model made to determine independent predictors of PEX syndrome (OR=0.59, CI=0.418-0.832, P=.003). Subclinical myocardial involvement in PEX syndrome, in which standard echocardiographic techniques are blinded, can be detected by the strain echocardiography. PEX causes deterioration in the deformation parameters of the left ventricle. Systemic involvement should not be forgotten in patients with PEX and cardiac functions should be monitored.

A deep learning approach with temporal consistency for automatic myocardial segmentation of quantitative myocardial contrast echocardiography.

Quantitative myocardial contrast echocardiography (MCE) has been proved to be valuable in detecting myocardial ischemia. During quantitative MCE analysis, myocardial segmentation is a critical step in determining accurate region of interests (ROIs). However, traditional myocardial segmentation mainly relies on manual tracing of myocardial contours, which is time-consuming and laborious. To solve this problem, we propose a fully automatic myocardial segmentation framework that can segment myocardial regions in MCE accurately without human intervention. A total of 100 patients' MCE sequences were divided into a training set and a test set according to a 7: 3 proportion for analysis. We proposed a bi-directional training schema, which incorporated temporal information of forward and backward direction among frames in MCE sequences to ensure temporal consistency by combining convolutional neural network with recurrent neural network. Experiment results demonstrated that compared with a traditional segmentation model (U-net) and the model considering only forward temporal information (U-net + forward), our framework achieved the highest segmentation precision in Dice coefficient (U-net vs U-net + forward vs our framework: 0.78 ± 0.07 vs 0.79 ± 0.07 vs 0.81 ± 0.07, p < 0.01), Intersection over Union (0.65 ± 0.09 vs 0.66 ± 0.09 vs 0.68 ± 0.09, p < 0.01), and lowest Hausdorff Distance (32.68 ± 14.6 vs 28.69 ± 13.18 vs 27.59 ± 12.82 pixel point, p < 0.01). In the visual grading study, the performance of our framework was the best among these three models (52.47 ± 4.29 vs 54.53 ± 5.10 vs 57.30 ± 4.73, p < 0.01). A case report on a randomly selected subject for perfusion analysis showed that the perfusion parameters generated by using myocardial segmentation of our proposed framework were similar to that of the expert annotation. The proposed framework could generate more precise myocardial segmentation when compared with traditional methods. The perfusion parameters generated by these myocardial segmentations have a good similarity to that of manual annotation, suggesting that it has the potential to be utilized in routine clinical practice.

The physiologic and prognostic value of regional longitudinal strain during dipyridamole stress echocardiography

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Investigaciones Médicas, Cardiodiagnostic Background. Regional apical longitudinal strain (RALS) allows to corroborate the diagnosis of regional wall motion abnormalities (RWMA) during dipyridamole stress echocardiography (DSE) on a quantitative basis but data on the prognostic value are missing. Objectives. The to evaluate the physiologic correlates and prognostic value of RALS vs. RWMA during DSE. Methods. In a single center, observational design we initially evaluated 150 patients (pts), mean age 68.3 ± 9.6 years, 50.7% men referred for DSE. RALS was defined as the average of the four apical segments from the 3 apical views. Any increase in the percentage of deformation was considered normal. Coronary flow velocity reserve (CFVR) was also assessed in mid-distal left anterior descending (LAD) coronary artery by pulsed-wave Doppler. Pts were divided into two groups (G). G1: patients with normal RALS, and G2: patients with abnormal RALS. Major cardiovascular event was considered to be: cardiovascular death, acute myocardial infraction (AMI), stroke or needs for revascularization after 3 months All patients were followed-up. Results. RALS success rate was 94.6% (142 pts), since 8 pts were excluded for inadequeate window. Eighty-seven patients (61.3%) were included in G1 and 55 (38.7%) pts in G2. The mean follow-up was 36 ± 0.93 months. There were no differences in the resting RALS between the G1 and G2 (-22.3% ± 3.3 vs -21.25% ± 4.9, p = NS), but significant differences in the peak dipyridamole effect (-26.3% ± 4.2 vs -18.8% ± 4.1, p &amp;lt; 0.001). Pts G1 showed less RWMA than pts G2 (G1 3.4% vs G2 90 %), p &amp;lt; 0.001) and higher CFVR (G1= 2.6 ± 0.5 vs G2 = 1.6 ± 0.4, p &amp;lt; 0.001). Adequeate CFVR showed high concordance with the increase in RALS evaluated by Kappa Index 0.95, p 0.001 (Pts G1= 98.9% vs pts G2= 96.4%). In the long-term follow up, 24 pts experienced events: 3 deaths, 3 non-fatal myocardial infarctions, 2 stroke and 16 late revascularizations. Pts with normal RALS had a better event-free survival (G1= 90.8% vs G2 = 70.9%, log Rank p &amp;lt; 0.007, HR: 2.92; 95% CI: 1.27-6.68, p 0.011) (figure 1). In the multivariate analysis of logistic regression, adjusted for age, the RALS was an independent predictor of event. In G2 no significant differences were detected in event free survival in pts with and without visual dyssynergies during DSE (73.7 vs 67.7, respectively (p = ns) Conclusions. A mismatch between RALS and visually assessed RWMA occurs in a significant proportion of patients, and RALS is better correlated to physiologic (CFVR) and prognostic standards. Abnormal RALS during DSE predicted worse outcome, regardless of the RWMA. Quantitative stress echocardiography is possible feasible and useful during DSE. Abstract Figure. RALS in DSE and Event Free Survival

Prognostic validation of partition values for quantitative parameters to grade functional tricuspid regurgitation severity by conventional echocardiography.

Quantitative echocardiography parameters are seldom used to grade tricuspid regurgitation (TR) severity due to relative paucity of validation studies and lack of prognostic data. To assess the relationship between TR severity and the composite endpoint of death and hospitalization for congestive heart failure (CHF); and to identify the threshold values of vena contracta width (VCavg), effective regurgitant orifice area (EROA), regurgitant volume (RegVol), and regurgitant fraction (RegFr) to define low, intermediate, and high-risk TR based on patients' outcome data. A cohort of 296 patients with at least mild TR underwent 2D, 3D, and Doppler echocardiography. We built statistical models (adjusted for age, NYHA class, left ventricular ejection fraction, and pulmonary artery systolic pressure) for VCavg, EROA, RegVol, and RegFr to study their relationships with the hazard of outcome. The tertiles of the derived hazard values defined the threshold values of the quantitative parameters for TR severity grading. During 47-month follow-up, 32 deaths and 72 CHF occurred. Event-free rate was 14%, 48%, and 93% in patients with severe, moderate, and mild TR, respectively. Severe TR was graded as VCavg > 6 mm, EROA > 0.30 cm2, RegVol > 30 mL, and RegF > 45%. This outcome study demonstrates the prognostic value of quantitative parameters of TR severity and provides prognostically meaningful threshold values to grade TR severity in low, intermediate, and high risk.

Abstract 15055: Quantitative Echocardiography of the Left Atrium: Traditional Measurement by Manual Planimetry Can be Replaced by Automated Four-dimensional Imaging That is More Efficient and Provides Additional Information

Background: Manual volume measurement of the left atrium (LA) using two-dimensional (2D) imaging is time consuming and mainly produces volumetric information. Hypothesis: LA chamber quantification by semi-automated four-dimensional (4D) imaging may be more efficient and produces both volume and comprehensive functional analysis. Methods: Fifty subjects from the Healthy eHeart cohort of normal echocardiograms studied at the Research Cardiac Physiology Laboratory were selected by representative LA volumes. Studies were performed on a GE Vivid E95. Plainimetry was done on LA 2D images from apical 2 and 4 chamber views. Biplane LA maximal volume index (LAVImax) and minimal volume index (LAVImin) were calculated by method of discs. LA 4D images were obtained from an apical 4 chamber view. LA volume was calculated using a commercially available 4D Auto LAQ package. All 2D and 4D measurements were repeated at random by a sonographer. Analysis times for each LA volume quantitation were recorded. Intra-observer reproducibility was analyzed by coefficient of variation (CV). Results: Mean age of subjects was 51 ± 17 years (60% male). On 2D analysis, mean LAVImax was 26.7 ± 9.5 ml/m2 and mean LAVImin was 10.9 ± 4.4 ml/m2. Intra-observer reproducibility showed a CV of 9.1% for LAVImax and 8% for LAVImin. On 4D analysis, mean LAVImax was 27.2 ± 8.9 ml/m2 and mean LAVImin was 11.8 ± 3.9 ml/m2. Intra-observer reproducibility showed a CV of 4.0% for LAVImax and 5.0% for LAVImin. Time for LA volume quantification was 74 ± 15 seconds for 4D vs. 195 ± 30 seconds for 2D, p &lt; 0.001. The 4D analysis offered a LA volume curve, LA global longitudinal strain, and a real time 4D LA image that 2D did not. Conclusion: Acquisition and analysis of LA volume by 4D echocardiogram using a 4D Auto LAQ package requires less time than 2D analysis while producing a more comprehensive and reproducible result. It is worth considering advancing 4D LA quantification to a first-line method in clinically quantitating LA function.

A Novel Mouse Model to Study Image-Guided, Radiation-Induced Cardiac Injury and Identify Clinically Relevant Predictors of Toxicity

Radiation (RT)-induced cardiac injury is a significant concern in thoracic oncology patients. The aim of this study was to develop a novel mouse model for RT-induced cardiotoxicity, which could be used to identify molecular pathophysiology and clinically-targetable biomarkers of disease development. We hypothesized that partial heart +/- lung RT would elicit dose-dependent cardiac dysfunction, perfusion deficits, inflammation, and vascular injury. Female C57BL/6 mice aged 9-11 weeks were administered an intravenous contrast agent (fenestraVC, ART Advanced Research Technologies, Saint-Laurent, Q) to visualize the heart on cone-beam computed tomography imaging using the Small Animal Radiation Research Platform. A single dose of photon RT at 0, 20, 40, or 60 Gy was delivered to the cardiac apex +/- lung using a 3x3 mm collimator and stereotactic body RT, and gamma-H2AX staining was used to confirm targeting. Quantitative echocardiography and single positron emission computed tomography (SPECT) with Technicium-99 sestamibi were implemented to evaluate myocardial function and perfusion respectively. Cardiac tissue and plasma were collected for multiparametric analysis of biochemical markers of RT injury and tissue was harvested for histologic analysis. RT resulted in dose-dependent systolic and diastolic dysfunction as measured by regional hypokinesis, decreased left ventricular ejection fraction (LVEF) (p = 0.0001, 60 Gy), and increased E/E’ (ratio between early mitral inflow velocity and mitral annular early diastolic velocity) (p = 0.002, 60 Gy) on echocardiography 8 weeks post-RT. Compared to control, apical perfusion deficits were noted on SPECT 8 weeks post-RT only at a dose of 60 Gy, with quantitative analysis revealing a reduction in tracer uptake regionally (p = 0.003, 60 Gy) and globally (nonsignificant). At 2 weeks post-RT, increases in troponin T (TnT), placental growth factor (PLGF), interleukin (IL)-6, IL-10, and tumor necrosis factor alpha (TNFa) were observed in irradiated cardiac tissue or plasma, with more pronounced increases in all cytokine levels post 40 Gy partial heart and lung RT compared to 60 Gy partial heart RT alone. Histology demonstrated perivascular fibrosis (p<0.05) and vessel lumen narrowing. A mouse model of RT-induced cardiotoxicity can be generated by the in-situ focal irradiation of the heart, and can be used to integrate radiomic and biochemical markers of cardiotoxicity to inform early therapeutic intervention.Abstract 3256; TableSelect radiologic and biochemical dataPartial heart RT dose (Gy)LVEF (%)E/E’Lateral wall apical uptake on SPECT#TnT#PLGF#IL-2#IL-6#IL-10#TNFa#067.328.2-------4062.2*33.30.710.93.6***----6053.5***36.4**0.65**2.0**15.5**1.41.73.91.8*40+lung63.831.10.543.8*8.31.85.8*8.7*3.8*#Values normalized to 0 Gy *P < 0.05; **P < 0.005; ***P < 0.0005. Open table in a new tab

Feasibility of evaluating the left ventricular function in patients with cardiovascular diseases by fully automatic quantified three-dimensional transthoracic echocardiography

Objective: To investigate the clinical value of left ventricular function assessment in patients with cardiovascular disease by fully automatic quantified three-dimensional transthoracic echocardiography. Methods: One hundred and ninety-seven patients with cardiac diseases were examined by three-dimensional transthoracic echocardiography from September 2017 to May 2019. Data from 61 patients with grade 1 echocardiographic image quality were used to determine the default boundary values of endocardial end-diastolic and end-systolic phases. Clinical features were analyzed based on electronic medical records. The accuracy and repeatability of this strategy was evaluated by comparing left ventricular end-diastolic volume (LVEDV), end-systolic volume (LVESV) and left ventricular ejection fraction (LVEF) measured by automated quantitative three-dimensional echocardiography and those measured by conventional manual transthoracic echocardiography, the latter served as gold standard. Results: The levels of LVEDV, LVESV and LVEF measured by automatic three-dimensional echocardiography were positively correlated with values obtained by manual measurement（r=0.97，0.97, 0.98, 0.97, 0.97, 0.96；P<0.05). The levels of LVEDV and LVESV measured by full-automatic three-dimensional echocardiography were significantly higher than those obtained by manual three-dimensional echocardiography（all P<0.05）. The classification and correlation of systolic dysfunction in patients with abnormal ventricular wall motion by automatic three-dimensional echocardiography were significantly improved after manual calibration (κ=0.74, P=0.00) as compared to without manual calibration (κ=0.63, P=0.00). The inter-observer and intra-observer variability of fully automated three-dimensional echocardiography were significantly smaller than manual three-dimensional echocardiography（both P<0.05）. Conclusion: Fully automatic quantified three-dimensional transthoracic echocardiography possesses excellent accuracy and repeatability in measuring left ventricular volume and function， and it is feasible for clinical application.