Effect of shape of the stenosis on the hemodynamics of a stenosed coronary artery

Abstract

In this study, the effect of the shape of the stenosis on the flow transition in an artery is investigated. Different shapes of the stenosis including round, oval, elongated, half-moon, bean-shape, and crescent with and without eccentricity at a constant degree of stenosis (73%) are studied. A computational model, validated against the in-house Particle Image Velocimetry experimental results, is used to investigate the flow behavior. The results showed that the length of the jet region after the stenotic section varies significantly for different shapes of the stenosis. Based on the analysis of turbulent kinetic energy, power spectral density, and the spectral entropy of stream-wise velocity fluctuations, it was shown that eddies are formed after the dissipation of jet flow downstream of the stenosis. It was also shown that the intensity of the velocity fluctuations differs for different shapes of the stenosis. Furthermore, using the proper orthogonal decomposition method, it was shown that the shape of the stenosis has a significant impact on the downstream coherent structures. It was found that regardless of the degree of stenosis, specific shapes of the stenosis, such as round concentric, create less serious hemodynamic complications compared to the other shapes of the stenosis.

Smartphone-based particle image velocimetry for cardiovascular flows applications: A focus on coronary arteries

“…An explanation for this only apparently contradictory result is in the fact that the uncertainty generated by particles blurring in strong gradient regions of the fluid domain using smart-PIV cannot be accounted for by the present a posteriori uncertainty quantification approach but can only be ascertained through comparison with conventional PIV. Relatively high normalized estimated displacement errors affecting conventional PIV measurements can also be observed in the recirculation region ( Figure 11 ), due to an out-of-plane motion generated by the separated flow ( Peng et al, 2016 ; Freidoonimehr et al, 2021b ). Similarly, the post-stenotic jet measurements were associated with an increment of at ≈ 0.6 mm ( Figure 11 ), where the realistic 3D geometry of the phantom and the jet flow are expected to generate local out-of-plane motion ( Ding et al, 2021 ).…”

“…In the last two decades, particle image velocimetry (PIV) has become a standard technique for the reliable in vitro quantitative characterization of fluid dynamics in implantable devices such as prosthetic heart valves ( Manning et al, 2003 ; Leo et al, 2006 ; Dasi et al, 2007 ; Kaminsky et al, 2007 ; Dasi et al, 2008 ; Ge et al, 2008 ; Hasler et al, 2016 ; Hasler and Obrist, 2018 ; Becsek et al, 2020 ) and stents ( Charonko et al, 2009 ; Charonko et al, 2010 ; Raben et al, 2015 ; Brindise et al, 2017 ; Freidoonimehr et al, 2021a ), in blood recirculating devices such as extracorporeal membrane oxygenators, mechanical circulatory supports, blood pumps and hemodialysis systems ( Giridharan et al, 2011 ; Raben et al, 2016 ; Malinauskas et al, 2017 ), as well as in idealized and realistic phantoms of healthy and diseased vessels ( Bluestein et al, 1997 ; Brunette et al, 2008 ; Ford et al, 2008 ; Kefayati and Poepping, 2013 ; Büsen et al, 2017 ; Shintani et al, 2018 ; DiCarlo et al, 2019 ; Salman et al, 2019 ; Medero et al, 2020 ; Freidoonimehr et al, 2021b ).…”

Numerical simulation of pulsatile blood flow through eccentric double stenosed carotid artery

“…In the case of eccentricity, previous studies used a wide range of eccentricity with minimum of 5% (Varghese et al , 2007) to a maximum of fully eccentric, i.e. 100% (Freidoonimehr et al , 2021). In the present case, a small eccentricity of 0.1D (10%) was provided at the location of stenosis to observe any distinction in flow features downstream of the blockage against the axisymmetric case.…”

Numerical modeling of varying hemodynamic features with changing internal carotid artery bifurcation angles and degrees of stenosis

“…Typically, these approximations are inspired by CT-scans and MRI-scans previously published of patient-specific stenosed arteries [53,54]. Freidoonimehr et al [55] demonstrate the influence of different stenosis shapes have on the downstream flow behavior mentioning that the downstream velocity profiles do not vary heavily with different eccentric stenosis shapes. However, flow transitional behavior, coherent structures, and re-laminarization of downstream flow vary steeply from one shape to another.…”