A numerical investigation of the functionality of coronary bifurcation lesions with respect to lesion configuration and stenosis severity

Pagiatakis, Catherine; Tardif, Jean‐Claude; L’Allier, Philippe L.; Mongrain, Rosaire

doi:10.1016/j.jbiomech.2015.07.018

Cited by 12 publications

(14 citation statements)

References 63 publications

(68 reference statements)

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“…Surprisingly, there are no additional values necessary for the use of 3D‐QCA analysis to predict either FFR <0.80 or <0.75. This may be explained by the fact that not only lesion stenosis severity but also specific angiographic features including tandem lesion, true bifurcation, lesion length, and distance from the ostium were determined as independent predictors of positive FFR . These findings also suggested that 3D‐QCA can be used to solve the problems caused by foreshortening; however, a major limitation of the 3D system itself, caused by luminology, is the unsolved problem of vessel diameter measurement.…”

Section: Discussionmentioning

confidence: 99%

Comparison between two‐dimensional and three‐dimensional quantitative coronary angiography for the prediction of functional severity in true bifurcation lesions: Insights from the randomized DK‐CRUSH II, III, and IV trials

Zhang

Zhu

Shi

et al. 2016

Cathet Cardio Intervent

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Section: Discussionmentioning

confidence: 99%

Comparison between two‐dimensional and three‐dimensional quantitative coronary angiography for the prediction of functional severity in true bifurcation lesions: Insights from the randomized DK‐CRUSH II, III, and IV trials

Zhang

Zhu

Shi

et al. 2016

Cathet Cardio Intervent

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“…In a more realistic geometry, namely a carotid bifurcation, transitional flow was only observed close to the stenosis for higher local Reynolds numbers (peak Reynolds number of ~1200 at the stenosis) [ 55 ]. Thus, in our study the flow was assumed to be laminar in all cases for comparative purposes and to simplify numerics, as previously done in [ 13 ]. This assumption is conservative because it might result in a slightly underestimation of the pressure drops for the extreme cases, leading to the calculation of slightly higher FFR values.…”

Section: Discussionmentioning

confidence: 99%

Coronary fractional flow reserve measurements of a stenosed side branch: a computational study investigating the influence of the bifurcation angle

et al. 2016

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BackgroundCoronary hemodynamics and physiology specific for bifurcation lesions was not well understood. To investigate the influence of the bifurcation angle on the intracoronary hemodynamics of side branch (SB) lesions computational fluid dynamics simulations were performed.MethodsA parametric model representing a left anterior descending—first diagonal coronary bifurcation lesion was created according to the literature. Diameters obeyed fractal branching laws. Proximal and distal main branch (DMB) stenoses were both set at 60 %. We varied the distal bifurcation angles (40°, 55°, and 70°), the flow splits to the DMB and SB (55 %:45 %, 65 %:35 %, and 75 %:25 %), and the SB stenoses (40, 60, and 80 %), resulting in 27 simulations. Fractional flow reserve, defined as the ratio between the mean distal stenosis and mean aortic pressure during maximal hyperemia, was calculated for the DMB and SB (FFRSB) for all simulations.ResultsThe largest differences in FFRSB comparing the largest and smallest bifurcation angles were 0.02 (in cases with 40 % SB stenosis, irrespective of the assumed flow split) and 0.05 (in cases with 60 % SB stenosis, flow split 55 %:45 %). When the SB stenosis was 80 %, the difference in FFRSB between the largest and smallest bifurcation angle was 0.33 (flow split 55 %:45 %). By describing the ΔPSB−QSB relationship using a quadratic curve for cases with 80 % SB stenosis, we found that the curve was steeper (i.e. higher flow resistance) when bifurcation angle increases (ΔP = 0.451*Q + 0.010*Q2 and ΔP = 0.687*Q + 0.017*Q2 for 40° and 70° bifurcation angle, respectively). Our analyses revealed complex hemodynamics in all cases with evident counter-rotating helical flow structures. Larger bifurcation angles resulted in more pronounced helical flow structures (i.e. higher helicity intensity), when 60 or 80 % SB stenoses were present. A good correlation (R2 = 0.80) between the SB pressure drop and helicity intensity was also found.ConclusionsOur analyses showed that, in bifurcation lesions with 60 % MB stenosis and 80 % SB stenosis, SB pressure drop is higher for larger bifurcation angles suggesting higher flow resistance (i.e. curves describing the ΔPSB−QSB relationship being steeper). When the SB stenosis is mild (40 %) or moderate (60 %), SB resistance is minimally influenced by the bifurcation angle, with differences not being clinically meaningful. Our findings also highlighted the complex interplay between anatomy, pressure drops, and blood flow helicity in bifurcations.

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“…In these equations, ρ and μ are the blood density and viscosity and were assumed to be 1056 kg m −3 and 0.0035 Pa · s respectively 42,45,48 . Moreover,

\overset{u}{true}

is the velocity vector and p is the pressure field.…”

Section: Methodsmentioning

confidence: 99%

“…43 For this purpose, typically, LMCA and its bifurcations, meaning LAD and LCX, which are the most prone sites of stenosis, are generated as a 3D model. 44 Although several studies have calculated the amount of FFR and local hemodynamic parameters in ideal bifurcations, 45,46 to achieve patient-relevant results, it is better to employ patient-specific models. These models can be provided through CT angiographic images with details such as location, degrees of stenosis, LL, and MLD of real stenosis plus angulation of bifurcation and geometric curvature.…”

Section: D Patient-specific Model Of Left Coronary Arteriesmentioning

confidence: 99%

High precision invasive FFR, low‐cost invasive iFR, or non‐invasive CFR?: optimum assessment of coronary artery stenosis based on the patient‐specific computational models

Tajeddini

Nikmaneshi

Firoozabadi

et al. 2020

Numer Methods Biomed Eng

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The objective of this paper is to apply computational fluid dynamic (CFD) as a complementary tool for clinical tests to not only predict the present and future status of left coronary artery stenosis but also to evaluate some clinical hypotheses. In order to assess the present status of the coronary artery stenosis severity, and thereby selecting the most appropriate type of treatment for each patient, fractional flow reserve (FFR), instantaneous wave free-ratio (iFR), and coronary flow reserve (CFR) are calculated. To examine FFR, iFR, and CFR results, the effect of geometric features of stenoses, including diameter reduction (%), lesion length (LL), and minimum lumen diameter (MLD), is studied on them. It is observed that FFR is a more conservative index than iFR and CFR to assess the severity of coronary stenosis. In addition, it is seen that FFR, iFR, and CFR decrease by increasing LL and decreasing MLD. Therefore, the morphological indices, LL/MLD and LL/MLD^4, with the calculated conservative cutoff values equal to 5.5 and 3.6, are considered. Next, some controversial clinical hypotheses about the assessment of the severity of coronary stenosis are evaluated numerically. These include the examination of FFR, iFR, and CFR accuracies, investigating the effect of coronary hyperemia on iFR, as well as the reliability of the hybrid iFR-FFR decision-making strategy. The presented numerical model can also be used as a predictive tool to identify the atherosuseptible sites of arteries by calculating the time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and relative residence time (RRT).

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A numerical investigation of the functionality of coronary bifurcation lesions with respect to lesion configuration and stenosis severity

Cited by 12 publications

References 63 publications

Comparison between two‐dimensional and three‐dimensional quantitative coronary angiography for the prediction of functional severity in true bifurcation lesions: Insights from the randomized DK‐CRUSH II, III, and IV trials

Comparison between two‐dimensional and three‐dimensional quantitative coronary angiography for the prediction of functional severity in true bifurcation lesions: Insights from the randomized DK‐CRUSH II, III, and IV trials

Coronary fractional flow reserve measurements of a stenosed side branch: a computational study investigating the influence of the bifurcation angle

High precision invasive FFR, low‐cost invasive iFR, or non‐invasive CFR?: optimum assessment of coronary artery stenosis based on the patient‐specific computational models

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