Hemodynamic numerical simulations of the disturbance due to intracoronary flow measurements by a Doppler guide wire

Abstract

BackgroundSince hemodynamics plays a key role in the development and evolution of cardiovascular pathologies, physician’s decision must be based on proper monitoring of relevant physiological flow quantities.MethodsA numerical analysis of the error introduced by an intravascular Doppler guide wire on the peak velocity measurements has been carried out. The effect of probe misalignment (±10°) with respect to the vessel axis was investigated. Numerical simulations were performed on a realistic 3D geometry, reconstructed from coronary angiography images. Furthermore, instead of using Poiseuille or Womersley approximations, the unsteady pulsatile inlet boundary condition has been calculated from experimental peak-velocity measurements inside the vessel through a new approach based on an iterative Newton’s algorithm.ResultsThe results show that the presence of the guide modifies significantly both the maximum velocity and the peak position in the section plane; the difference is between 6 and 17% of the maximum measured velocity depending on the distance from the probe tip and the instantaneous vessel flow rate. Furthermore, a misalignment of the probe may lead to a wrong estimation of the peak velocity with an error up to 10% depending on the probe orientation angle.ConclusionsThe Doppler probe does affect the maximum velocity and its position during intravascular Doppler measurements. Moreover, the Doppler-probe-wire sampling volume at 5.2 and 10 mm far from the probe tip is not sufficient to prevent its influence on the measurement. This should be taken into account in clinical practice by physicians during intravascular Doppler quantification. The new numerical approach used in this work could potentially be helpful in future numerical simulations to set plausible inlet boundary conditions.Electronic supplementary materialThe online version of this article (doi:10.1186/s12938-016-0234-6) contains supplementary material, which is available to authorized users.

Monolithic Integration of Ultraslim Flow Sensor and Medical Guidewire by Laser Filament Scanning Sintering for In Vivo Diagnostics of Cardiovascular Diseases

“…The representative measurement methods of blood flow changes for CVD diagnosis are divided into blood pressure-based methods, such as fractal flow reserve (FFR) and instantaneous wave-free ratio, , and blood flow velocity-based methods, such as intravascular Doppler method and thermal dilution. − Pressure-sensing methods for measuring blood flow have limited accuracy because they rely on indirect estimation of blood flow changes based on the pressure difference between the aorta and the site past the lesion. For example, a long moderate stenosis within a coronary artery may result in a false low FFR due to reduced pressure, whereas a high microvascular resistance may lead to an apparently high FFR.…”