Longitudinal Shortening Research Articles

Mitral annular plane systolic excursion for assessing left ventricular systolic dysfunction in patients with septic shock

BackgroundUsing easy-to-determine bedside measurements, we developed an echocardiographic algorithm for predicting left ventricular ejection fraction (LVEF) and longitudinal strain (LVLS) in patients with septic shock. MethodsWe measured septal and lateral mitral annular plane systolic excursion (MAPSE), septal and lateral mitral S-wave velocity, and the left ventricular longitudinal wall fractional shortening in patients with septic shock. We used a conditional inference tree method to build a stratification algorithm. The left ventricular systolic dysfunction was defined as an LVEF <50%, an LVLS greater than −17%, or both. ResultsWe included 71 patients (males: 61%; mean [standard deviation] age: 61 [15] yr). Septal MAPSE (cut-off: 1.2 cm) was the best predictor of left ventricular systolic dysfunction. The level of agreement between the septal MAPSE and the left ventricular systolic dysfunction was 0.525 [0.299–0.751]. A septal MAPSE ≥1.2 cm predicted normal LVEF in 17/18 patients, or 94%. In contrast, a septal MAPSE <1.2 cm predicted left ventricular systolic dysfunction with impaired LVLS in 46/53 patients (87%), although 32/53 (60%) patients had a preserved LVEF. ConclusionsSeptal MAPSE is easily measured at the bedside and might help clinicians to detect left ventricular systolic dysfunction early—especially when myocardial strain measurements are not feasible.

Transfer Length and Prestress Losses of a Prestressed Concrete Box Girder with 18 mm Straight Strands

Despite the potential advantages of 18 mm strands, the limited research on the behavior of girders with larger-diameter strands hinders the application in bridges. Transfer length and prestress losses are two important indicators. In this research, a 32.6 m long prestressed concrete box girder with 18 mm straight strands and 15 mm harped strands was produced, and the transfer length and the prestress losses were studied. The transfer length was calculated based on the existing equations in codes and previous research. Three beam specimens were fabricated, and strain gauges were pasted on the concrete surface to measure the transfer length of 18 mm strands. It indicated that the average measured transfer length was 700 mm. This value was smaller than the transfer lengths predicted by AASHTO LRFD 2017 and ACI 318-19, while Mitchell’s equation offered the closest prediction to the average measured transfer length. Additionally, the prestress losses at different stages were evaluated. A one-end stressing test was conducted to analyze the effect of strand harping on the loss of tensile force. In comparison with the actual measured loss based on the concrete strain and the longitudinal shortening, the instantaneous prestress loss calculated using the AASTHO LRFD 2017 alternative equation was appropriate. The time-dependent prestress losses due to shrinkage, creep, and relaxation were predicted using two different methods addressed in AASHTO LRFD 2017. The time-dependent predicted losses of 69.2 MPa at 28 d using the refined method were 37% higher than the measured losses 47.4 MPa at 28 d, indicating an overestimation of AASHTO LRFD 2017. The accumulation of the total losses over time revealed that the prestress losses developed in the first two months occupied the majority of the total losses in the long term. The research may provide guidelines for the design of a pretensioned concrete box girder with 18 mm strands.

Fully automated AI-based cardiac motion parameter extraction – application to mitral and tricuspid valves on long-axis cine MR images

PurposeIn cardiac MRI, valve motion parameters can be useful for the diagnosis of cardiac dysfunction. In this study, a fully automated AI-based valve tracking system was developed and evaluated on 2- or 4-chamber view cine series on a large cardiac MR dataset. Automatically derived motion parameters include atrioventricular plane displacement (AVPD), velocities (AVPV), mitral or tricuspid annular plane systolic excursion (MAPSE, TAPSE), or longitudinal shortening (LS). MethodTwo sequential neural networks with an intermediate processing step are applied to localize the target and track the landmarks throughout the cardiac cycle. Initially, a localisation network is used to perform heatmap regression of the target landmarks, such as mitral, tricuspid valve annulus as well as apex points. Then, a registration network is applied to track these landmarks using deformation fields. Based on these outputs, motion parameters were derived. ResultsThe accuracy of the system resulted in deviations of 1.44 ± 1.32 mm, 1.51 ± 1.46 cm/s, 2.21 ± 1.81 mm, 2.40 ± 1.97 mm, 2.50 ± 2.06 mm for AVPD, AVPV, MAPSE, TAPSE and LS, respectively. Application on a large patient database (N = 5289) revealed a mean MAPSE and LS of 9.5 ± 3.0 mm and 15.9 ± 3.9 % on 2-chamber and 4-chamber views, respectively. A mean TAPSE and LS of 13.4 ± 4.7 mm and 21.4 ± 6.9 % was measured. ConclusionThe results demonstrate the versatility of the proposed system for automatic extraction of various valve-related motion parameters.

Clinical and functional relevance of right ventricular contraction patterns in pulmonary hypertension

The right ventricle has a complex contraction pattern of uncertain clinical relevance. We aimed to assess the relationship between right ventricular (RV) contraction pattern and RV-pulmonary arterial (PA) coupling defined by the gold-standard pressure-volume loop-derived ratio of end-systolic/arterial elastance (Ees/Ea). Prospectively enrolled patients with suspected or confirmed pulmonary hypertension underwent three-dimensional echocardiography, standard right heart catheterization, and RV conductance catheterization. RV-PA uncoupling was categorized as severe (Ees/Ea < 0.8), moderate (Ees/Ea 0.8-1.29), and none/mild (Ees/Ea ≥ 1.3). Clinical severity was determined from hemodynamics using a truncated version of the 2022 European Society of Cardiology/European Respiratory Society risk stratification scheme. Fifty-three patients were included, 23 with no/mild, 24 with moderate, and 6 with severe uncoupling. Longitudinal shortening was decreased in patients with moderate vs no/mild uncoupling (p<0.001) and intermediate vs low hemodynamic risk (p<0.001), discriminating low risk from intermediate/high risk with an optimal threshold of 18% (sensitivity 80%, specificity 87%). Anteroposterior shortening was impaired in patients with severe vs moderate uncoupling (p=0.033), low vs intermediate risk (p=0.018), and high vs intermediate risk (p=0.010), discriminating high risk from intermediate/low risk with an optimal threshold of 15% (sensitivity 100%, specificity 83%). Left ventricular (LV) end-diastolic volume was decreased in patients with severe uncoupling (p=0.035 vs no/mild uncoupling). Early RV-PA uncoupling is associated with reduced longitudinal function, whereas advanced RV-PA uncoupling is associated with reduced anteroposterior movement and LV preload, all in a risk-related fashion. GOV: NCT04663217.

Regional motion of the AV-plane is related to the cardiac anatomy and deformation of the AV-plane. Data from the HUNT Study.

The study examines global and regional systolic shortening of the left (LV) and right ventricle (RV) in 1266 individuals without evidence of heart disease in the third wave of the HUNT study. Regional mitral annular systolic displacement (MAPSE) was 1.5 cm in the septum and anterior walls, 1.6 cm in the lateral wall and 1.7 cm in the inferior wall, global mean 1.6 cm. Peak systolic velocity S' was 8.0, 8.3, 8.8 and 8.6 cm/s in the same walls (global mean 8.7 cm/s). All measures of LV longitudinal shortening correlated, mean MAPSE and S' also correlated with stroke volume (SV) and ejection fraction (EF). Global longitudinal strain by either method correlated with MAPSE, S' and EF, but not with SV, reflecting a systematic difference. S' and MAPSE correlated with early annular diastolic velocity (e'), reflecting that e' is the recoil from systole. Mean displacement was 2.8 (0.5) cm in the tricuspid annulus (TAPSE). Normal values by age and sex are provided. Both TAPSE and S' were lower in women, where body size explained the sex difference. Normalization of MAPSE and S' for wall length reduced intra-individual variation of displacement and velocity by 80 - 90%, showing regional MAPSE to be related to LV wall length, and that longitudinal wall strain was relatively uniform. Displacement and S' were lowest in the septum and highest in the left and right free walls, shows systolic bending of the AV-plane into a U-shape, relating to the total cardiac volume changes during the heart cycle. This article is protected by copyright. All rights reserved.

Comprehensive mechanical performance characteristics of newly developed ultra-thin coronary stents

Endovascular technologies such as percutaneous transluminal coronary angioplasty and stenting are widely used due to being minimally invasive procedures. One of the endovascular devices, a drug-eluting stent (DES), proved to be a safe and effective therapeutic option for cardiologists, substantially reducing in-stent restenosis (ISR) rates. DES consists of thin (< 200 µm) or ultra-thin (< 70 µm) struts made of Cobalt-Chromium (CoCr) or other alloys. The DES with ultra-thin struts exhibits higher longitudinal flexibility and improved trackability. It also reduces vascular injury and promotes more rapid endothelization, substantially decreasing the risk of ISR. This study evaluates comprehensive mechanical performances of two different structural designs of newly developed ultra-thin CoCr stents (i.e., strut width of 75 µm or 65 µm). These two stent designs are engineered with distinct bridge size and distribution patterns, prioritizing enhanced flexibility irrespective of the strut thickness. Computational modeling results show anticipated stress distribution with maximum local stresses, which are compared with experimental outcomes conducted in this study. ASTM guideline based in vitro experimental studies have been conducted to assess the stents’ longitudinal flexibility, radial strength, recoil and shortening, as well as crushability through this study. Three-point bending experiments have demonstrated that the stent design 1 requires less bending force compared to the design 2, showing better longitudinal flexibility of the stent design 1 in the collapsed state for the new ultra-thin DES devices. The design 1 also showed superior radial strength and recoiling phenomena, as well as smaller shortening. In short, the stent design 1 shows better mechanical performance needed for the coronary artery DES.

Association of left ventricular ejection fraction and long axis function across health and disease

Abstract Funding Acknowledgements Type of funding sources: None. Background Global longitudinal shortening (GLSh) 1,2 and left ventricular ejection fraction (LVEF) are different measures of left ventricular function. LVEF is well-established, but can miss early or mild disease. GLSh, which quantifies long-axis shortening, is easy to measure, and has been shown to have superior reproducibility and prognostication ability than global longitudinal strain3,4. Purpose To assess the relationship between GLSh and EF measured using CMR in a large cohort representing health (healthy volunteers, athletes) and disease (hypertension, aortic stenosis, hypertrophic cardiomyopathy(HCM),cardiac amyloidosis, Fabry disease). Methods CMR scans from a study cohort of 932 subjects were analysed (121 healthy volunteers, 278 athletes, 40 patients with hypertension, 76 severe aortic stenosis, 164 HCM, 51 cardiac amyloidosis, 202 Fabry). EF and GLSh were automatically measured from standard CMR SSFP cine images using machine learning methods described previously3,5. Correlation coefficients between GLSh and LVEF were calculated for each disease category. Normal reference ranges for LVEF and GLSh were estimated from a subset of n=4,342 healthy subjects from the UK Biobank, who had no history of cardiovascular disease or medication use. Results The lower limit of normal in the UK Biobank healthy subjects was 55% for EF and 13% for GLSh. Across the study cohort, for subjects with normal LVEF, only a small minority of healthy volunteers (n=1, 0.8%) and athletes(n=2; 0.7%) had low GLSh, whereas rates increased progressively in hypertension(n=3;9%), Fabry(n=61;31%), aortic stenosis(n=26;44%), HCM (n=87; 56%), and cardiac amyloidosis(N=28; 93%). Conversely, few subjects (n=8/932;0.1%) have the opposite: normal LGSh but low LVEF(Figure 1). The relationship between LVEF and GLSh is shown in Figure 2. Apart from HCM (r=0.019,p = 0.8), all other diseases show a significant association between GLSh and LVEF, with progressively higher correlation from healthy volunteers (r=0.33 p&amp;lt;0.001) to cardiac amyloidosis (r=0.33; p = 0.0016), athletes (r=0.44; p&amp;lt;0.001), and hypertension (R=0.6; p&amp;lt;0.001), with aortic stenosis showing highest correlation (r=0.68,p&amp;lt;0.001). Fabrys patients showed the reverse trend, with an inverse correlation between GLSh and LVEF (r=-0.34; p&amp;lt;0.001). Conclusions In health, impaired GLSh is rare when LVEF is normal, however across diseases with hypertrophy, GLSh impairment is common, illustrating the potential of GLSh to detecting early or mild systolic impairment. There are unexpectedly different associations between GLS and EF. In some diseases, these appears to measure the same aspects (health/AS/hypertension), but in others they are not well correlated with GLS providing new information. In Fabry, there is an unexpected inverse relationship. Further work is needed to understand this.

Sleep parameters might affect the attrition of leukocyte telomere length

AbstractBackgroundThe relationship between sleep parameters and longitudinal shortening of telomere length is unclear. This study aimed to investigate the relationship between sleep parameters and the shortening of leukocyte telomere length (LTL) over two years.MethodAmong the participants in the validation cohort of the Korea Brain Aging Study for the Early Diagnosis and Prediction of Alzheimer’s Disease, participants who measured both baseline and follow‐up (two years later) of LTL were analyzed. They were dichotomized according to the degree of LTL attrition. Clinical characteristics, including sleep duration, sleep latency, Pittsburgh Sleep Quality Index (PSQI), Stanford Sleepiness Scale, and Epworth Sleepiness Scale scores were compared between the two groups.ResultA total of 238 patients were analyzed in current study. Participants with faster LTL shortening had a shorter duration of sleep (P = 0.013) and longer sleep latency (P = 0.007). Among the components of the PSQI, subjective measures of sleep quality, sleep latency, sleep duration, and sleep efficiency were significantly worse in participants with faster LTL shortening. Multivariate logistic regression analysis showed that sleep latency (odds ratio [OR] = 1.015, confidence interval [CI] = 1.001–1.029, P = 0.029), global PSQI score (OR = 1.130, CI = 1.017–1.256, P = 0.023), shortest sleep duration (OR = 5.057, CI = 1.189–21.502; P = 0.028), and lowest sleep efficiency (OR = 8.598, CI = 1.584–46.672, P = 0.013) were independently associated with faster LTL shortening.ConclusionPoor sleep quality, specifically long sleep latency, less than 5 hours of sleep, and low sleep efficiency were associated with faster longitudinal shortening of the LTL.

The Right Ventricular Systolic Function Assessment in Adult Respiratory Distress Syndrome: Simple. Basic. Complex.

To the Editor: We thank Dr. Dandel for his interest in our previously published article.1 We acknowledge that the pathogenicity of dominant SARS-COV-2 “variants of concern” during the second wave (Delta variant) may partially explain the higher mortality observed during the second wave. However, other factors, including steroid-resistant disease and changes in clinical management, should not be discarded.1 Dr. Dandel also suggested that right ventricular (RV) failure may be the primary cause of the high mortality rate of our ECMO patients observed during the second wave. Unfortunately, no precise and objective data supports this hypothesis in our series. However, we agree with Dr. Dandel on two essential points: First, we agree that in moderate-to-severe ARDS, the clinical impact of routinely monitoring RV systolic function with bedside echocardiography is obvious. An early diagnosis of RV systolic dysfunction to adapt medical management (ventilatory parameters, fluids, and vasopressors) is essential. However, choosing the most appropriate parameters to monitor RV systolic function is difficult. Classical parameters seem to have poor sensitivity to detect RV dysfunction2 and poor prognostic value.3 Using RV strain parameters to assess RV systolic function is promising, but the clinical significance for COVID-19-associated ARDS (C-ARDS) is still under debate.4 Nevertheless, advanced two-dimensional speckle tracking parameters, such as RV longitudinal shortening fraction (RV-LSF), seem more accurate. We recently reported in a cohort of 86 moderate-to-severe C-ARDS patients that RV dysfunction (defined by an RV-LSF < 20%) was frequent (43%) and was associated with 30-day mortality.5 Moreover, RV-LSF seems to be the most reliable parameter for assessing RV systolic function in patients with acute core pulmonale.6 The use of these parameters to choose the most appropriate support needs confirmation. Second, echocardiographic data before implementation and during ECMO therapy are, indeed, very useful. However, many factors (ultra-protective ventilation, prone positioning sessions, ventilator mode, pump/sweep gas flow...) can modify RV morphology and function under ECMO therapy. In this situation, distinguishing between RV adaptation and failure is difficult. That is why choosing relevant parameters to identify RV systolic dysfunction and the need for a standardized monitoring protocol are mandatory. Further studies are required to assess the feasibility, reproducibility, and clinical impact of the various RV parameters (conventional and advanced) that may be used during ECMO therapy. We agree that timely repeated ultrasound exams with heart/lung interaction evaluation are of utmost importance during the ECMO course.

Intrafasciomembranal Fluid Pressure: A Novel Approach to the Etiology of Myalgias, Part II.

The fascia forms a hierarchy of spaces (small and large compartments) that contain and enclose muscle fibers, fiber bundles, skeletal muscles, and compartments of several skeletal muscles. Solid fascia serves as a membrane that enables an increased volume and fluid pressure within such a fasciomembrane, an intrafasciomembrial fluid pressure (IFMFP). Increased IFMFP provides a theoretical model and a common explanation for the etiology of the myalgias: trigger point (TrP), chronic exertional compartment syndrome (CECS), overtraining syndrome (OTS), and delayed onset muscle soreness (DOMS). Many myalgias and their symptoms are poorly understood, and this review aims to provide an extension to this theoretical model and novel approach. This review suggests that the swelling from elevated IFMFP also likely leads to a longitudinal shortening of the same affected tissue. This model of swelling and shortening provides additional explanations for the changes in the lines of force through the body that can lead to changes in the body's posture and, thus, to compensatory movements. This new approximation also provides a biomechanical explanation for the thickening of the fascia and referred pain, and also suggests that IFMFP is a factor in weather-related pain.

Evaluation of right ventricular strain in two separate cohorts with precapillary pulmonary hypertension.

Evaluation for right ventricular (RV)dysfunction is an important part of risk assessment in care of patients with pulmonary hypertension (PH) as it is associated with morbidity and mortality. Echocardiography provides a widely available and acceptable method to assess RV function. RV global longitudinal strain (RVGLS), a measure of longitudinal shortening of RV deep muscle fibers obtained by two-dimensional echocardiography, was previously shown to predict short-term mortality in patients with PH. The purpose of the current study was to assess the performance of RVGLS in predicting 1-year outcomes in PH. We retrospectively identified 83 subjects with precapillary PH and then enrolled 50 consecutive prevalent pulmonary arterial hypertension (PAH) subjects into a prospective validation cohort. Death as well as combined morbidity and mortality events at 1 year were assessed as outcomes. In the retrospective cohort, 84% of patients had PAH and the overall 1-year mortality rate was 16%. Less negative RVGLS was marginally better than tricuspid annular plane systolic excursion(TAPSE)as a predictor for death. However, in the prospective cohort, 1-year mortality was only 2%, and RVGLS was not predictive of death or a combined morbidity and mortality outcome. This study supports that RV strain and TAPSE have similar 1-year outcome predictions but highlights that low TAPSE or less negative RV strain measures are often false-positive in a cohort with low baseline mortality risk. While RV failure is considered the final common pathway for disease progression in PAH, echocardiographic measures of RV function may be less informative of risk in serial follow-up of treated PAH patients.

Interchangeability of right ventricular longitudinal shortening fraction assessed by transthoracic and transoesophageal echocardiography in the perioperative setting: A prospective study.

Conventional transthoracic (TTE) and transoesophageal echocardiography (TEE) parameters assessing right ventricle (RV) systolic function are daily used assuming their clinical interchangeability. RV longitudinal shortening fraction (RV-LSF) is a two-dimensional speckle tracking parameter used to assess RV systolic function. RV-LSF is based on tricuspid annular displacement analysis and could be measured with TTE or TEE. The aim of the study was to determine if RV-LSFTTE and RV-LSFTEE measurements were interchangeable in the perioperative setting. Prospective perioperative TTE and TEE echocardiography were performed under general anesthesia during scheduled cardiac surgery in 90 patients. RV-LSF was measured by semi-automatic software. Comparisons were performed using Pearson correlation and Bland-Altman plots. RV-LSF clinical agreement was determined as a range of -5 to 5%. Of the 114 patients who met the inclusion criteria, 90 were included. The mean preoperative RV-LSFTTE was 20.4 ± 4.3 and 21.1 ± 4.1% for RV-LSFTEE. The agreement between RV-LSF measurements was excellent, with a bias at -0.61 and limits of agreement of -4.18 to 2.97 %. All measurements fell within the determined clinical agreement interval in the Bland-Altman plot. Linear regression analysis showed a high correlation between RV-LSFTTE and RV-LSFTEE measurement (r = 0.9; confidence interval [CI] 95%: [0.87-0.94], p < 0.001). RV-LSFTTE and RV-LSFTEE measurements are interchangeable, allowing RV-LSF to be a helpful parameter for assessing perioperative changes in RV systolic function. NCT05404737. https://www.clinicaltrials.gov/ct2/show/NCT05404737.

Plasma FGF23 is associated with left atrial remodeling in children on hemodialysis.

FGF23 mediates cardiac fibrosis through the activation of pro-fibrotic factors in in vitro models and is markedly elevated in kidney disease. Left atrial global longitudinal strain (LA GLS) derived by echocardiographic speckle-tracking measures longitudinal shortening of the LA walls, quantifies atrial performance and may enable detection of early LA remodeling in the setting of normal ventricular function. We hypothesized that LA GLS is abnormal in children on hemodialysis (HD) compared to healthy controls of comparable age/sex distribution and that, among HD patients, greater FGF23 levels are associated with abnormal LA GLS. Clinical and echocardiographic data from 29 children receiving HD and 13 healthy controls were collected in a cross-sectional single-center study. Plasma FGF23 concentrations were measured using ELISA. The primary outcome was LA GLS measured using 2D speckle-tracking strain analysis. Linear regression analysis was used to investigate predictors of LA GLS in HD. Median dialysis vintage was 1.5 (IQR 0.5-4.3) years. Median intact FGF23 levels were substantially higher in the HD vs. control group (1206 [215, 4707] vs. 51 [43, 66.5] pg/ml; P = 0.0001), and LA GLS was 39.9% SD 11.6 vs. 32.8% SD 5.7 (P = 0.04). Among HD patients, higher FGF23 was associated with lower LA GLS (β per unit Ln-FGF23: - 2.7; 95% CI slope - 5.4, - 0.1; P = 0.04 after adjustment for age, body size, and HD vintage. FGF23 was not associated with LA phasic reservoir, conduit, or contractile strain. In children on HD and preserved left ventricularejection fraction, greater FGF23 is associated with lower LA GLS (indicative of impaired atrial performance). A higher resolution version of the Graphical abstract is available as Supplementary information.

Global longitudinal strain corresponds to number of coronary vessels diseased even among patients with reduced left ventricular ejection fraction

Global longitudinal shortening (GLS), a measurement of left ventricular myocardial deformation obtained from 2-dimensional speckle tracking Doppler echocardiography, is usually abnormal in patients with reduced left ventricular ejection fraction (LVEF).

Myocardial Wringing and Rigid Rotation in Cardiac Amyloidosis

BackgroundThe motion of the heart is a result of the helicoidal arrangement of the myofibers in the organ’s wall. We aimed to study the relationship between the wringing motion state and the degree of ventricular function in patients with cardiac amyloidosis (CA). MethodsFifty patients with CA and decreased global longitudinal strain (LS) were evaluated using 2-dimensional speckle-tracking echocardiography. We have expressed LS as positive values to facilitate understanding. Normal twist, which occurs when basal and apical rotations occur in opposite directions, was coded as positive. When the apex and base rotate in the same direction (rigid rotation), twist was coded as negative. Left ventricular (LV) wringing (calculated as twist/LS, which takes into account actions that occur simultaneously during LV systole [ie, longitudinal shortening and twist]) was evaluated according to LV ejection fraction (LVEF). ResultsMost of the patients (66%) who participated in the study were diagnosed with transthyretin amyloidosis. A positive relationship was observed between wringing and LVEF (r = 0.75, P < 0.0001). In advanced stages of ventricular dysfunction, rigid rotation appeared in 66.6% of patients with LVEF ≤ 40%, in whom negative values of twist and wringing were observed. LV wringing proved to be a good discriminator of LVEF (area under the curve 0.90, P < 0.001, 95% confidence interval 0.79-0.97); for example, wringing < 1.30°/% detected LVEF < 50% with 85.7% sensibility and 89.7% specificity. ConclusionsWringing, which integrates twist and simultaneous LV longitudinal shortening, is a conditioning rotational parameter of the degree of ventricular function in patients with CA.

Behavior of echocardiographic parameters of right ventricular function after tricuspid surgery

Evaluation of right ventricular (RV) function after tricuspid valve surgery is complex. The objective was to identify the most appropriate RV function parameters for this purpose. This prospective study included 70 patients undergoing cardiac and tricuspid valve (TV) surgery. RV size and function parameters were determined at 3 months and 1-year post-surgery. Categorical variables were analyzed with the McNemar test and numerical variables with the Student’s t-test for related samples or, when non-normally distributed, the Wilcoxon test. Spearman's rho was used to determine correlations between variables at 3 months and 1 year. RV diameters were reduced at 3 months post-surgery and were then unchanged at 1 year. Tricuspid annular plane systolic excursion (TAPSE) and S′ wave values were worse at 3 months and then improved at 1 year (t-score-2.35, p 0.023; t-score-2.68; p 0.010). There was no significant reduction in free wall longitudinal strain (LS) or shortening fraction (SF) at 3 months (t-score 1.421 and − 1.251; p 0.218 and 0.172), and they were only slightly below pre-surgical values at 1 year. No relationship was found between RV function parameters and mortality or major complications. During the first few months after TV surgery, LS may be a more appropriate parameter to evaluate global ventricular function in comparison to TAPSE. At 1 year, good correlations are observed between TAPSE, S′ wave, and LS values.

Experimental, numerical and design investigations on the performance of axially-loaded ECFT stub columns with spherical-cap gaps

Elliptical concrete-filled steel tubular (ECFT) columns have been increasingly used in engineering practice in recent years due to their aesthetic appeal together with structural advantages. The spherical-cap gaps were generally found in the actual CFT structures based on the latest survey. However, related literatures on the ECFT stub columns with spherical-cap gaps (ECFT-SG) under axial load are rarely reported. Thus, this paper aims to reveal the effects of gaps on the performance of axially-loaded ECFT stub columns. In total, ten axially-loaded ECFT-SG specimens were tested to explore the effects of gap ratio (χsg) and steel yield strength (fy) on the failure modes, axial fore (N) – longitudinal shortening (Δ), strain responses, strength and ductility indexes, etc. Following this, a series of numerical models using a modified equivalent concrete stress-strain relationship were established to expand the parametric scope and further study the steel-concrete interaction stresses and the concrete longitudinal stress distribution. Finally, two strength prediction methods of ECFT-SG stub columns were presented. The results indicated that the initial concrete gaps would weaken the confinement effect provided by steel tube, thus decrease the initial stiffness, ultimate strength and ductility of the columns. With the χsg increasing, the overall bending and inward buckling phenomena would be observed because of the uneven damage of infill concrete. The two design methods proposed herein are expected to provide a reference to evaluate the safety of the existing CFT columns with initial gap imperfection.

Body mass index associated differences in cardiac stress energetics in type 2 diabetes

Abstract Background Patients with T2D and heart disease have normal body mass index (BMI), suggesting that diabetes and obesity mediate cardiovascular change by different mechanisms. Changes in cardiac energy metabolism in lean diabetic patients during exercise stress have not been previously reported. Objectives We aimed to assess if there are BMI-associated differences in cardiac stress metabolism in patients with T2D. Methods Twenty-five overweight T2D patients (O-T2D) and eleven lean T2D patients (LnT2D), age- and ethnicity-matched and with no other comorbidities were studied. Patients were on oral hypoglycaemics only and were free of diabetes complications. Participants underwent rest and dobutamine stress phosphorus magnetic resonance spectroscopy (31P-MRS) and cardiovascular magnetic resonance (CMR) at 3T for the assessment of myocardial phosphocreatine to ATP ratio (PCr/ATP) as a measure of myocardial energetics, biventricular volumes, rest and stress left ventricular (LV) ejection fraction, global longitudinal shortening, and mitral in-flow E/A ratio for assessment of diastolic function and perfusion. Intravenous Dobutamine was administered at a dose of 10μg/kg/min, increasing at 90 second intervals up to a maximum of 40 μg/kg/min to achieve a target heart rate of 65% of the age-predicted maximal heart rate. Mean rate pressure product (RPP) was recorded at rest and stress. Heart rate was maintained at target for the duration of the 31P-MRS and stress CMR cine, mitral in-flow and perfusion acquisitions. Results The cardiac volumes, systolic or diastolic function and LV mass were similar between LnT2D and O-T2D. Although the O-T2D patients had a numerically lower rest and stress PCr/ATP ratio, this did not reach statistical significance. Resting PCr/ATP was reduced in LnT2D and O-T2D patients similarly. However, LnT2D showed a greater reduction in PCr/ATP (stress PCr/ATP LnT2D 1.51±0.2 vs O-T2D 1.41±0.25, p=0.02) despite similar increases in RPP. Stress myocardial blood flow (MBF) was also significantly lower in the O-T2D patients. There were significant correlations of BMI with LV mass (r=0.35, p=0.03); stress LVEF (r=−0.34, p=0.04); stress MBF stress (r=−0.53, p=0.001) and stress E/A (r=0.46, p=0.01) (figure 1). Conclusions Despite their better stress perfusion and similar glycaemic control, LnT2D show worse metabolic reserve characterised by more significant decrements in energetics in response to hemodynamic stress compared to overweight patients with T2D. Higher BMI correlates inversely with stress myocardial blood flow and with stress left ventricular ejection fraction. The presence of these subtle alterations in measures of stress metabolism and perfusion might signify a distinct metabolic phenotype of “lean diabetic cardiomyopathy”. Future studies are needed to further delineate alterations in cardiac energy metabolism in lean and overweight/obese type 2 diabetes patients, and their role in the development of cardiac dysfunction. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Wellcome TrustBHF

Maternal Cardiac Changes in Women With Obesity and Gestational Diabetes Mellitus.

We investigated if women with gestational diabetes mellitus (GDM) in the third trimester of pregnancy exhibit adverse cardiac alterations in myocardial energetics, function, or tissue characteristics. Thirty-eight healthy, pregnant women and 30 women with GDM were recruited. Participants underwent phosphorus MRS and cardiovascular magnetic resonance for assessment of myocardial energetics (phosphocreatine [PCr] to ATP ratio), tissue characteristics, biventricular volumes and ejection fractions, left ventricular (LV) mass, global longitudinal shortening (GLS), and mitral in-flow E-wave to A-wave ratio. Participants were matched for age, gestational age, and ethnicity. The following data are reported as mean ± SD. The women with GDM had higher BMI (27 ± 4 vs. 33 ± 5 kg/m2; P = 0.0001) and systolic (115 ± 11 vs. 121 ± 13 mmHg; P = 0.04) and diastolic (72 ± 7 vs. 76 ± 9 mmHg; P = 0.04) blood pressures. There was no difference in N-terminal pro-brain natriuretic peptide concentrations between the groups. The women with GDM had lower myocardial PCr to ATP ratio (2.2 ± 0.3 vs. 1.9 ± 0.4; P < 0.0001), accompanied by lower LV end-diastolic volumes (76 ± 12 vs. 67 ± 11 mL/m2; P = 0.002) and higher LV mass (90 ± 13 vs. 103 ± 18 g; P = 0.001). Although ventricular ejection fractions were similar, the GLS was reduced in women with GDM (-20% ± 3% vs. -18% ± 3%; P = 0.008). Despite no prior diagnosis of diabetes, women with obesity and GDM manifest impaired myocardial contractility and higher LV mass, associated with reductions in myocardial energetics in late pregnancy compared with lean women with healthy pregnancy. These findings may aid our understanding of the long-term cardiovascular risks associated with GDM.

Fully automatic AI-based valve motion parameter extraction on long axis CINE images - application on N=11000 patient datasets

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Research support from Siemens Healthineers GmbH. Background Mitral valve (MV) motion parameters, assessable using CMR [1, 2], have been shown to help the diagnosis of cardiac dysfunction. To extract valve motion parameters, we propose a fully automatic AI-based prototype system that tracks annulus and apex landmarks by the registration network on time-resolved two- and four-chamber CMR cine views. Parameters such as displacements, velocities, mitral annular plane systolic excursion (MAPSE), or longitudinal shortening (LS) are automatically extracted and evaluated on a large CMR dataset (N=11000). Methods The system consists of two sequential neural networks with a processing step in between (Fig. 1a) [3]. Initially, a 2D UNet is applied to localize both MV annulus insertion points as well as the apex. Based on these points, the image processing step consists of rotating, cropping, and interpolating the images, allowing a standardized image impression for both long axis views. Finally, the registration network (VoxelMorph framework [4]) is applied to the processed series and tracks the MV annulus insertion points and apex over the cardiac cycle by the deformation fields obtained by the network. The system was trained on (N=166) multivendor, multi-field strength, ground-truth annotated datasets [5]. A total of 11000 datasets, acquired on a 1.5T scanner (MAGNETOM Aera, Siemens Healthcare, Erlangen, Germany) from January 2016 to September 2017 [6], were used for parameter extraction. 200 of these datasets were additionally annotated semi-automatically for the performance evaluation of the system. Five motion parameters were automatically derived by the system that are defined as follows (Fig. 1b): (1) The atrioventricular plane displacement (AVPD) as the distance of the plane spanned by the MV annulus points relative to the first frame, (2) the atrioventricular plane velocity (AVPV) as the discrete temporal derivate of the AVPD, (3) the diameter of the annulus as the maximum distance between the MV annulus points, (4) the lateral/inferior and septal/superior MAPSE, as the maximum MV points’ excursion, and (5) the LS as the percentage size difference of the distance between the mid valvular point and the apex point at end-systole and end-diastole. Results The accuracy of the system resulted in deviations on the annotated dataset of 1.02 ± 0.87 mm, 0.01 ± 0.02 mm/s, 1.54 ± 1.21 mm, 2.30 ± 1.35 mm, 2.1 ± 1.8 mm for AVPD, AVPV, diameter, MAPSE, and LS respectively. Initial statistics on all datasets (Fig. 2) revealed a mean lateral/inferior, septal/superior MAPSE and LS of 8.7 ± 2.7 mm, 10.5 ± 3.2 mm and 16.3 ± 4.2 % for two-chamber and 9.6 ± 2.6 mm, 8.7 ± 2.6 mm and 15.5 ± 3.9 % for four-chamber views, respectively. Conclusions The results demonstrate the versatility of the proposed system for automatic extraction of various MV motion parameters. The proposed system enables automatic extraction of clinically relevant parameters and can improve the automation of MV-based analyses. System overview &amp; Parameter of interestsAnalysis of the extracted parameters