Cardiopulmonary Function in Thoracic Wall Deformities: What Do We Really Know?

2018 ◽  
Vol 28 (04) ◽  
pp. 327-346 ◽  
Author(s):  
Cristine Velazco ◽  
Venkata Pulivarthi ◽  
Reza Arsanjani ◽  
Robert Obermeyer ◽  
Dawn Jaroszewski
Keyword(s):  
Strain Rate ◽  
Pectus Excavatum ◽  
Surgical Repair ◽  
Exercise Intolerance ◽  
Thoracic Wall ◽  
Cardiac Chamber ◽  
Chest Wall Mechanics ◽  
Strain And Strain Rate ◽  
Cardiac Strain ◽  
Chamber Size

AbstractPatients with pectus excavatum (PE) frequently present with complaints of exercise intolerance and cardiopulmonary symptoms. There continues to be controversy regarding the physiologic benefits of repair. The aim of this review is to summarize and discuss recent data regarding the cardiopulmonary effects of PE deformity and the evidence for improvement obtained after surgical repair including (1) a greater efficiency of breathing (chest wall mechanics), (2) improvement in pulmonary restrictive deficits, (3) an increase in cardiac chamber size and output, with improved cardiac strain and strain rate, and (4) improvement in exercise capacity.

Abstract P059: Arterial Thickness and Stiffness are Independent Predictors of Myocardial Strain

Circulation ◽  
2015 ◽  
Vol 131 (suppl_1) ◽  
Author(s):  
Connie E McCoy ◽  
Philip R Khoury ◽  
Stephanie N Stewart ◽  
Lauren E Longhshore ◽  
Nicolas L Madsen ◽  
...  
Keyword(s):  
Young Adults ◽  
Strain Rate ◽  
Systolic Function ◽  
Systolic Dysfunction ◽  
Myocardial Strain ◽  
Structure And Function ◽  
Vascular Structure ◽  
Strain And Strain Rate ◽  
Cardiac Strain ◽  
And Function

Vascular dysfunction is associated with cardiac dysfunction, a precursor of CV events (MI,CHF) in adults. We hypothesized that abnormalities in vascular structure and function are associated with cardiac systolic dysfunction as measured by cardiac strain and strain rate in young adults. Carotid ultrasound and echocardiography were performed on 338 subjects (22.2 + 3.7 years; 38% male (M); 63% non-white (NW); 33% lean, 36% obese and 31% T2DM). CIMT was traced along the far wall of the distal CCA, bulb, and proximal ICA. Stiffness measures included carotid-femoral pulse wave velocity (PWVf), brachial distensibility (BrachD) and Peterson’s Elastic Modulus in the CCA (PEM). LV systolic function was assessed by global longitudinal (4-chamber) strain (GS) and strain rate in systole (GSRs). Anthropometry, BP, HR, fasting lipids, CRP, and glucose were collected. Correlations were calculated between vascular measures and cardiac strain. General linear models were constructed to determine if vascular measures were independent predictors of GS and GSRs. Covariates included age, sex, race, BMI z-score, MAP, group, TG, HDL, LDL, insulin, glucose, and CRP. GS and GSRs correlated with peripheral arterial stiffness (lower BrachD, higher PEM, higher PWVf) and structure (thicker CIMT), all p<.01 (Figure). After adjusting for other risk factors, BrachD was an independent predictor of poorer GSRs: GSRs=-1.1611 -.13*BrachD + .05 (if M) + .06 (if NW) + .004*MAP - .0003*glucose + .07*Insulin. CCA IMT independently predicted both GS and GSRs: GS=-.26 + 4.6* CCA + .92 (if M) + .58*BMIZ + .56*MAP- .03*HDL + 1.06*insulin; GSRs= -1.4 + .26*CCA+ .05 (if M) + .03*BMIZ + .003*MAP - .0003*glucose + .06*Insulin. All factors were significant at p<.05 in these models. We conclude that adverse pre-clinical vascular and cardiac findings are present in youth simultaneously and may increase risk for future CV events. Assessment of vascular structure and function may add incremental benefit in stratifying risk in young adults for future CV events.

Abstract 16138: Chest and Cardiac Compression on CT/MRI and on TEE Predicts Improvement in Right Heart Chamber Size and Right Ventricular Deformation Post Pectus Excavatum Repair Surgery

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Chieh-Ju Chao ◽  
Michael B Gotway ◽  
Dawn E Jaroszewski ◽  
Steven Lester ◽  
Samuel Unzek ◽  
...  
Keyword(s):  
Right Ventricular ◽  
Pectus Excavatum ◽  
Global Longitudinal Strain ◽  
Right Atrial ◽  
Right Heart ◽  
Cardiac Chamber ◽  
Heart Chamber ◽  
Cardiac Compression ◽  
2D Strain ◽  
Chamber Size

Background: Pectus excavatum (PE) deformity involves posterior depression of the sternum and adjacent costal cartilages. The relationship of CT/MRI chest cardiac compression indices used as indications for surgical repair of PE with echocardiographic findings and with improvement in cardiac chamber compression and function post PE repair is unknown. Methods: We evaluated right atrial (RA) size, tricuspid annulus (TA size, right ventricular (RV) outflow tract size as well as RV 2D strain on intra-operative trans-esophageal echocardiography (TEE) immediately pre and post surgical PE repair. Inspiratory and expiratory Haller Index (HI) and cardiac compression indices (CCI) were measured on pre op CT/MR scans (Figure). Offline measurement of chamber dimensions on TEE images was performed and Speckle tracking strain measurements were made using Syngo US Workplace software (Siemens). P<0.05 was considered significant. Results: 60 patients, 73% male, 27% female, age 33.6±10.3 yrs underwent PE repair following CT/MRI from 2010-2014 (Figure). There was a strong correlation between expiratory CT/MRI chest AP diameter and pre-op RA size (panel A). Pre op RA and TA compression on TEE inversely correlated with pre op RV global longitudinal strain rate(RVGLSR) (panels B & C). CCI predicted improvement in RA size post PE repair (panels D & E). In addition pre op RA size on TEE correlated with improvement in RVGLSR post PE repair surgery (panel F). Conclusion: In patients with PE deformity, pre surgical CCI correlated with right-sided cardiac chamber compression on pre op TEE. Severity of chest and cardiac compression also predicted magnitude of improvement in right-sided chamber size and RV longitudinal deformation post PE repair. Our findings provide insight regarding the beneficial effects of PE surgery on right heart chamber compression and improvement in RV function and the important role of intraoperative TEE for patients undergoing PE repair surgery.

Left Ventricular Diastolic Dysfunction and Exercise Intolerance in Obese Heart Failure with Preserved Ejection Fraction

2021 ◽  
Author(s):  
T. Jake Samuel ◽  
Dalane W. Kitzman ◽  
Mark J. Haykowsky ◽  
Bharathi Upadhya ◽  
Peter Brubaker ◽  
...  
Keyword(s):  
Heart Failure ◽  
Ejection Fraction ◽  
Strain Rate ◽  
Left Ventricular ◽  
Exercise Intolerance ◽  
Peak Exercise ◽  
Strain Rates ◽  
Preserved Ejection Fraction ◽  
Diastolic Strain Rate ◽  
Strain And Strain Rate

This study tested the hypothesis that early left ventricular (LV) relaxation is impaired in older obese heart failure with preserved ejection fraction (HFpEF) patients, and related to decreased peak exercise oxygen uptake (peak VO2). LV strain and strain rate were measured by feature tracking of magentic resonance cine images in 79 older obese HFpEF patients (mean age: 66 years; mean BMI: 38 kg/m2) and 54 healthy control participants. LV diastolic strain rates were indexed to cardiac preload as estimated by echocardiography derived diastolic filling pressures (E/e'), and correlated to peak VO2. LV circumferential early diastolic strain rate was impaired in HFpEF compared to controls (0.93±0.05 s-1 vs 1.20±0.07 s-1, p=0.014); however, we observed no group differences in early LV radial or longitudinal diastolic strain rates. Isolating myocardial relaxation by indexing all three early LV diastolic strain rates (i.e. circumferential, radial, and longitudinal) to E/e' amplified the group difference in early LV diastolic circumferential strain rate (0.08±0.03 vs 0.13±0.05, p<0.0001), and unmasked differences in early radial and longitudinal diastolic strain rate. Moreover, when indexing to E/e', early LV diastolic strain rates from all three principal strains, were modestly related with peak VO2 (R=0.36, -0.27, 0.35, respectively, all p<0.01); this response, however, was almost entirely driven by E/e' itself, (R=-0.52, P<0.001). Taken together, we found that while LV relaxation is impaired in older obese HFpEF patients, and modestly correlates with their severely reduced peak exercise VO2, LV filling pressures appear to play a much more important role in determining exercise intolerance.

Global Longitudinal Cardiac Strain and Strain Rate for Assessment of Fetal Cardiac Function: Novel Experience with Velocity Vector Imaging

2009 ◽  
Vol 26 (1) ◽  
pp. 28-36 ◽  
Author(s):  
Piers C.A. Barker ◽  
Helene Houle ◽  
Jennifer S. Li ◽  
Stephen Miller ◽  
James Rene Herlong ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Strain Rate ◽  
Velocity Vector ◽  
Fetal Cardiac Function ◽  
Velocity Vector Imaging ◽  
Strain And Strain Rate ◽  
Cardiac Strain

The effects of strain and strain rate on residual microstructures in copper

1986 ◽  
Vol 44 ◽  
pp. 420-421
Author(s):  
M. F. Stevens ◽  
P. S. Follansbee
Keyword(s):  
Strain Rate ◽  
Applied Stress ◽  
Threshold Stress ◽  
Rate Sensitivity ◽  
Viscous Drag ◽  
Strain Rates ◽  
Strain And Strain Rate ◽  
Threshold Strength ◽  
Mechanism Transition ◽  
Intrinsic Strength

The strain rate sensitivity of a variety of materials is known to increase rapidly at strain rates exceeding ∼103 sec-1. This transition has most often in the past been attributed to a transition from thermally activated guide to viscous drag control. An important condition for imposition of dislocation drag effects is that the applied stress, σ, must be on the order of or greater than the threshold stress, which is the flow stress at OK. From Fig. 1, it can be seen for OFE Cu that the ratio of the applied stress to threshold stress remains constant even at strain rates as high as 104 sec-1 suggesting that there is not a mechanism transition but that the intrinsic strength is increasing, since the threshold strength is a mechanical measure of intrinsic strength. These measurements were made at constant strain levels of 0.2, wnich is not a guarantee of constant microstructure. The increase in threshold stress at higher strain rates is a strong indication that the microstructural evolution is a function of strain rate and that the dependence becomes stronger at high strain rates.

scholarly journals Application of the Strain Compensation Model and Processing Maps for Description of Hot Deformation Behavior of Metastable β Titanium Alloy

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2021
Author(s):  
Oleksandr Lypchanskyi ◽  
Tomasz Śleboda ◽  
Aneta Łukaszek-Sołek ◽  
Krystian Zyguła ◽  
Marek Wojtaszek
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Flow Behavior ◽  
Microstructural Analysis ◽  
Calculated Data ◽  
Processing Temperature ◽  
Processing Maps ◽  
Compression Tests ◽  
Strain And Strain Rate ◽  
Average Absolute Relative Error

The flow behavior of metastable β titanium alloy was investigated basing on isothermal hot compression tests performed on Gleeble 3800 thermomechanical simulator at near and above β transus temperatures. The flow stress curves were obtained for deformation temperature range of 800–1100 °C and strain rate range of 0.01–100 s−1. The strain compensated constitutive model was developed using the Arrhenius-type equation. The high correlation coefficient (R) as well as low average absolute relative error (AARE) between the experimental and the calculated data confirmed a high accuracy of the developed model. The dynamic material modeling in combination with the Prasad stability criterion made it possible to generate processing maps for the investigated processing temperature, strain and strain rate ranges. The high material flow stability under investigated deformation conditions was revealed. The microstructural analysis provided additional information regarding the flow behavior and predominant deformation mechanism. It was found that dynamic recovery (DRV) was the main mechanism operating during the deformation of the investigated β titanium alloy.

A Study of Strain and Strain-Rate Dependent Properties of a Superplastic Zn-Al Alloy Under Biaxial Stresses

1982 ◽  
Vol 104 (1) ◽  
pp. 41-46
Author(s):  
T. C. Hsu ◽  
I. M. Bidhendi
Keyword(s):  
Strain Rate ◽  
Stress Ratio ◽  
Local Stress ◽  
Biaxial Stress ◽  
Al Alloy ◽  
Local Geometry ◽  
Forming Process ◽  
Rate Dependent ◽  
Strain And Strain Rate ◽  
Liquid Behavior

A superplastic Zn-Al alloy in sheet form is formed into a bulge over a circular hole by pneumatic pressure. The geometry, the stress, the strain, and the strain-rate are determined at various points covering the whole specimen and at various stages of the forming process. The complicated shape, and its complicated changes, are represented by introducing an index for the local geometry, called “prolateness,” which is also related to the local stress ratio in a simple way. The biaxial stress is analyzed into a strain-proportional and a strain-rate-proportional component, which represent, respectively, the quasi-solid and the quasi-liquid behavior of the superplastic material.

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