Alterations of Blood Flow Through Arteries Following Atherectomy and the Impact on Pressure Variation and Velocity

Abstract

Simulations were made of the pressure and velocity fields throughout an artery before and after removal of plaque using orbital atherectomy plus adjunctive balloon angioplasty or stenting. The calculations were carried out with an unsteady computational fluid dynamic solver that allows the fluid to naturally transition to turbulence. The results of the atherectomy procedure leads to an increased flow through the stenotic zone with a coincident decrease in pressure drop across the stenosis. The measured effect of atherectomy and adjunctive treatment showed decrease the systolic pressure drop by a factor of 2.3. Waveforms obtained from a measurements were input into a numerical simulation of blood flow through geometry obtained from medical imaging. From the numerical simulations, a detailed investigation of the sources of pressure loss was obtained. It is found that the major sources of pressure drop are related to the acceleration of blood through heavily occluded cross sections and the imperfect flow recovery downstream. This finding suggests that targeting only the most occluded parts of a stenosis would benefit the hemodynamics. The calculated change in systolic pressure drop through the lesion was a factor of 2.4, in excellent agreement with the measured improvement. The systolic and cardiac-cycle-average pressure results were compared with measurements made in a multi-patient study treated with orbital atherectomy and adjunctive treatment. The agreements between the measured and calculated systolic pressure drop before and after the treatment were within 3%. This excellent agreement adds further confidence to the results. This research demonstrates the use of orbital atherectomy to facilitate balloon expansion to restore blood flow and how pressure measurements can be utilized to optimize revascularization of occluded peripheral vessels.

A hemodynamic model with a seepage condition and fluid–structure interactions for blood flow in arteries with symmetric stenosis

“…Both the high pressure and the narrowing of blood vessels cause high flow velocity, high shear stress, and low or negative pressure at the throat of the stenosis [1]. Stenosis may create significant flow resistance and a large pressure drop [5,25]. Our results are found to be in excellent agreement with these facts.…”

Multiscale Boundary Conditions for Non-Fickian Diffusion Applied to Drug-Eluting Stents

“…Since blood is considered an isotropic Newtonian and laminar flow in the coronary arteries where the drug-eluting stents are typically implanted [14,9], we will assume the steady Navier-Stokes equations to model blood flow in the lumen. In fact, as discussed, e.g., in [2,28], the relevance of non-Newtonian effects in midsize arteries is negligible. For plasma filtration through the wall, assuming that both the intima and the media layers are porous media with isotropic and uniform permeability, we assume the Darcy equation.…”

“…Derivation of the solution. In this appendix we calculate the solution of the problem (25)-(28) presented in section 3. Letc 1 represent the Laplace transform of c 1 ; then from(25) and(26) we deduce∂ 2c 1 ∂x 2 (x, s) − λ 2 (s)c 1 (x, s) = − c 0 λ 2 (s) using the method of variation of parameters yields c 1 (x, s) = C 1 (s)e −λ(s)x + C 2 (s)e λ(s)x + c 0 s .From the boundary condition(27) we get thatc 1 (x, s) = C 1 (s) cosh (λ(s)x) + c 0 s ,(73)while from(28) it follows thatC 1 (s) = c out s − c 0 s 1 cosh (λ(s)L).Substituting the previous expression for C1 (s) into (73) gives c 1 (x, s) = c out cosh (λ(s)x) s cosh (λ(s)L) + c 0 (cosh (λ(s)L) − cosh (λ(s)x)) s cosh (λ(s)L) .…”

Peristaltic Transport with Viscous Dissipation Effect in a Multi-stenosed Artery

“…Even so, [39] studied analytically the transport of Low-Density Lipoprotein through an arterial wall under hyperthermia conditions using a four-layer model, and had results that are in excellent agreement with existing numerical and analytical literature data under isothermal conditions. [40] considered blood flow through arteries under atherectomy situation using an unsteady computational fluid dynamic solver, and found that the atherectomy procedure tends to increase the flow through the stenotic zone.…”