The effect of mild stenosis to flow in Trachea

2010 ◽  
Author(s):  
K. Osman ◽  
W.M. Basri ◽  
N.H. Johari ◽  
M. Rafiq
Keyword(s):  
Mild Stenosis

scholarly journals Coronary Flow and Reserve by Enhanced Transthoracic Doppler Trumps Coronary Anatomy by Computed Tomography in Assessing Coronary Artery Stenosis

Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 245
Author(s):  
Carlo Caiati ◽  
Arnaldo Scardapane ◽  
Fortunato Iacovelli ◽  
Paolo Pollice ◽  
Teresa Immacolata Achille ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Coronary Angiography ◽  
Flow Velocity ◽  
Coronary Flow ◽  
Invasive Coronary Angiography ◽  
Coronary Anatomy ◽  
Color Mapping ◽  
Flow Reserve ◽  
Mild Stenosis ◽  
Iodinated Contrast

We report the case of a 71-year-old patient with many risk factors for coronary atherosclerosis, who underwent computed coronary angiography (CTA), in accordance with the guidelines, for recent onset atypical chest pain. CTA revealed critical (>50% lumen diameter narrowing) stenosis of the proximal anterior descending coronary, and the patient was scheduled for invasive coronary angiography (ICA). Before ICA he underwent enhanced transthoracic echo-Doppler (E-Doppler TTE) for coronary flow detection by color-guided pulsed-wave Doppler recording of the left main (LMCA) and whole left anterior descending coronary artery (LAD,) along with coronary flow reserve (CFR) in the distal LAD calculated as the ratio, of peak flow velocity during i.v. adenosine (140 mcg/Kg/m) to resting flow velocity. E-Doppler TTE mapping revealed only mild stenosis (28% area narrowing) of the mid LAD and a CFR of 3.20, in perfect agreement with the color mapping showing no flow limiting stenosis in the LMCA and LAD. ICA revealed only a very mild stenosis in the mid LAD and mild atherosclerosis in the other coronaries (intimal irregularities). Thus, coronary stenosis was better predicted by E-Doppler TTE than by CTA. Coronary flow and reserve as assessed by E-Doppler TTE trumps coronary anatomy as assessed by CTA, without exposing the patient to harmful radiation and iodinated contrast medium.

scholarly journals Natural Progression of Low-Gradient Severe Aortic Stenosis with Preserved Ejection Fraction

2014 ◽  
Vol 41 (3) ◽  
pp. 273-279 ◽  
Author(s):  
Antony Leslie Innasimuthu ◽  
Sanjay Kumar ◽  
Jason Lazar ◽  
William E. Katz
Keyword(s):  
Aortic Stenosis ◽  
Ejection Fraction ◽  
Severe Aortic Stenosis ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Aortic Valve Area ◽  
Ventricular Ejection Fraction ◽  
Mild Stenosis ◽  
Natural Progression

Because the natural progression of low-gradient aortic stenosis (LGAS) has not been well defined, we performed a retrospective study of 116 consecutive patients with aortic stenosis who had undergone follow-up echocardiography at a median interval of 698 days (range, 371–1,020 d). All patients had preserved left ventricular ejection fraction (>0.50) during and after follow-up. At baseline, patients were classified by aortic valve area (AVA) as having mild stenosis (≥1.5 cm2), moderate stenosis (≥1 to <1.5 cm2), or severe stenosis (<1 cm2). Severe aortic stenosis was further classified by mean gradient (LGAS, mean <40 mmHg; high-gradient aortic stenosis [HGAS], mean ≥40 mmHg). We compared baseline and follow-up values among 4 groups: patients with mild stenosis, moderate stenosis, LGAS, and HGAS. At baseline, 30 patients had mild stenosis, 54 had moderate stenosis, 24 had LGAS, and 8 had HGAS. Compared with the moderate group, the LGAS group had lower AVA but similar mean gradient. Yet the actuarial curves for progressing to HGAS were significantly different: 25% of patients in LGAS reached HGAS status significantly earlier than did 25% of patients in the moderate-AS group (713 vs 881 d; P=0.035). Because LGAS has a high propensity to progress to HGAS, we propose that low-gradient aortic stenosis patients be closely monitored as a distinct subgroup that warrants more frequent echocardiographic follow-up.

Fractional flow reserve for a mild stenosis on the donor artery to chronic total occlusion

2012 ◽  
Vol 28 (2) ◽  
pp. 193-196 ◽  
Author(s):  
Harue Sasai ◽  
Kenichi Sakakura ◽  
Koichi Yuri ◽  
Hiroshi Wada ◽  
Kenshiro Arao ◽  
...  
Keyword(s):  
Fractional Flow Reserve ◽  
Chronic Total Occlusion ◽  
Fractional Flow ◽  
Total Occlusion ◽  
Flow Reserve ◽  
Mild Stenosis ◽  
Donor Artery

scholarly journals Mathematical Analysis of Non-Newtonian Blood Flow in Stenosis Narrow Arteries

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Somchai Sriyab
Keyword(s):  
Blood Flow ◽  
Skin Friction ◽  
Yield Stress ◽  
Newtonian Fluid ◽  
Mathematical Analysis ◽  
Viscosity Coefficient ◽  
Plasma Viscosity ◽  
Casson Model ◽  
Mild Stenosis ◽  
Normal Artery

The flow of blood in narrow arteries with bell-shaped mild stenosis is investigated that treats blood as non-Newtonian fluid by using the K-L model. When skin friction and resistance of blood flow are normalized with respect to non-Newtonian blood in normal artery, the results present the effect of stenosis length. When skin friction and resistance of blood flow are normalized with respect to Newtonian blood in stenosis artery, the results present the effect of non-Newtonian blood. The effect of stenosis length and effect of non-Newtonian fluid on skin friction are consistent with the Casson model in which the skin friction increases with the increase of ither stenosis length or the yield stress but the skin friction decreases with the increase of plasma viscosity coefficient. The effect of stenosis length and effect of non-Newtonian fluid on resistance of blood flow are contradictory. The resistance of blood flow (when normalized by non-Newtonian blood in normal artery) increases when either the plasma viscosity coefficient or the yield stress increases, but it decreases with the increase of stenosis length. The resistance of blood flow (when normalized by Newtonian blood in stenosis artery) decreases when either the plasma viscosity coefficient or the yield stress increases, but it decreases with the increase of stenosis length.

Effect of Partial Slip on Peristaltic Flow of a Sisko Fluid with Mild Stenosis through a Porous Medium

2016 ◽  
Vol 10 (2) ◽  
pp. 673-687 ◽  
Author(s):  
Nabil T. M. El-dabe ◽  
Galal M. Moatimid ◽  
Mohamed A. Hassan ◽  
Doaa R. Mostapha
Keyword(s):  
Porous Medium ◽  
Peristaltic Flow ◽  
Partial Slip ◽  
Sisko Fluid ◽  
Mild Stenosis
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