Flow in shock tubes with area change at the diaphragm section

1958 ◽  
Vol 3 (05) ◽  
pp. 457 ◽  
Author(s):  
R. A. Alpher ◽  
D. R. White
Keyword(s):  
2020 ◽  
Vol 14 (4) ◽  
pp. 614-617
Author(s):  
A. D. Kiverin ◽  
K. O. Minaev ◽  
I. S. Yakovenko
Keyword(s):  

2020 ◽  
Vol 313 ◽  
pp. 112191
Author(s):  
Kang Rao ◽  
Huafeng Liu ◽  
Xiaoli Wei ◽  
Wenjie Wu ◽  
Chenyuan Hu ◽  
...  

2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
J Peteiro ◽  
M Rivadulla-Varela ◽  
B Bouzas-Zubeldia ◽  
I Martinez-Bendayan ◽  
A Bouzas-Mosquera ◽  
...  

Abstract Funding Acknowledgements Type of funding sources: None. Introduction The evaluation of right ventricular (RV) function in patients with  tetralogy of Fallot (TF)  is important as it could impact outcome. Further exhaustive assessments with exercise might offer added information. We aimed to evaluate different parameters of RV function and their changes during exercise echocardiography (ExE) in patients with TF, and to correlate them with functional capacity Methods Treadmill ExE was performed in 31 consecutive patients with corrected TF (mean age 36 ± 11, 22 male), all of them asymptomatic. Left ventricular function was studied at peak exercise, whereas RV function parameters were acquired during the immediate post-exercise period (<1.5 min), along with mitral, tricuspid and pulmonary regurgitation (PR), transtricuspid and transpulmonary systolic gradients, and LV-E/e´ values. RV function was assessed by tricuspid annulus plane systolic excursion (TAPSE), S wave velocity in the RV lateral annulus, and RV area change. A blunted functional capacity (BFC) was considered in case of achieving <100% of the predicted metabolic equivalents (METs) during ExE, according to age and gender. Results Only 1 patient had symptoms during ExE (dyspnea). Achieved METs were 13 ± 3.5 and 10 patients (32%) had BFC. LV ejection fraction (%) changed with exercise from 58 ± 10 to 63 ± 9 (p = 0.05) and E/e´ from 11 ± 4 to 10 ± 3 (p = 0.04). TAPSE did not change (19 ± 5 at rest; 21 ± 7 at exercise; p = NS), neither RV area change (41 ± 11 cm2 at rest; 39 ± 12 cm2 at exercise; p = NS), whereas TDI-S increased from 10.5 ± 2.8 to 13.8 ± 3.1 cm2/s (p < 0.001), and systolic pulmonary pressure from 20 ± 8 to 27 ± 12 mmHg (p = 0.001). Patients with BFC had more frequently significant PR at rest (60% vs 14%; p = 0.015), lower peak systolic blood pressure (152 ± 30 vs 176 ± 24 mmHg, p = 0.02) and higher exercise E/e´ (12.6 ± 2.7 vs 8.9 ± 3.0; p = 0.003), without differ in other parameters. Δ-TDI-S correlated with achieved METs and with the percent achieved of predicted METs (r = 0.46; p = 0.01, y r = 0.47; p = 0.008, respectively). In conclusion, TDI-S assessment at the tricuspid annulus is a useful parameter for assessing RV function during exercise in subjects with TF. Abstract Figure.


2016 ◽  
Vol 92 ◽  
pp. 19-23 ◽  
Author(s):  
Adam T. James ◽  
John David Corcoran ◽  
Orla Franklin ◽  
Afif Faisal EL-Khuffash

Author(s):  
Ritobrata Sur ◽  
Shengkai Wang ◽  
Kai Sun ◽  
David F. Davidson ◽  
Jay B. Jeffries ◽  
...  
Keyword(s):  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Monika Colombo ◽  
Yong He ◽  
Anna Corti ◽  
Diego Gallo ◽  
Stefano Casarin ◽  
...  

AbstractIn-stent restenosis (ISR) is the major drawback of superficial femoral artery (SFA) stenting. Abnormal hemodynamics after stent implantation seems to promote the development of ISR. Accordingly, this study aims to investigate the impact of local hemodynamics on lumen remodeling in human stented SFA lesions. Ten SFA models were reconstructed at 1-week and 1-year follow-up from computed tomography images. Patient-specific computational fluid dynamics simulations were performed to relate the local hemodynamics at 1-week, expressed in terms of time-averaged wall shear stress (TAWSS), oscillatory shear index and relative residence time, with the lumen remodeling at 1-year, quantified as the change of lumen area between 1-week and 1-year. The TAWSS was negatively associated with the lumen area change (ρ = − 0.75, p = 0.013). The surface area exposed to low TAWSS was positively correlated with the lumen area change (ρ = 0.69, p = 0.026). No significant correlations were present between the other hemodynamic descriptors and lumen area change. The low TAWSS was the best predictive marker of lumen remodeling (positive predictive value of 44.8%). Moreover, stent length and overlapping were predictor of ISR at follow-up. Despite the limited number of analyzed lesions, the overall findings suggest an association between abnormal patterns of WSS after stenting and lumen remodeling.


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