Guidewire Flow Obstruction Effect on Diagnosis of Coronary Lesion Severity: In-Vitro Experimental and Numerical Study
The transstenotic pressure drop is one of the important basic fluid mechanics parameters used to assess the coronary stenosis severity along with FFR and CFR. Clinically, the transstenotic pressure or pressure drop and flow are measured by inserting a sensor tipped guidewire of diameter 0.014" across the stenosis. The guidewire insertion across the coronary stenosis alters the transstenotic hemodynamics by producing “artifactual blockage” which causes reduction in pharmacologically induced hyperemic flow and increase in transstenotic pressure drop. This guidewire flow obstruction was reported in the in-vivo studies by many clinicians [Anderson et al 1986, Wilson et al. 1988]. The guidewire flow obstruction effect was quantified in the in-vitro experiments previously by De Bruyne et al. 1993, Lipscomb et al. 1978, Ganz et al. 1985, Young and Tsai 1973. However, these studies were performed with steady flow and Newtonian viscosity of blood analog fluid. Hence, these studies can not be used to draw any true physiological conclusion. In this multi-arrayed experimental study followed by subsequent numerical validation, the transstenotic pressure drop and guidewire flow obstruction effect are quantified under pulsatile flow conditions and non-Newtonian blood analog fluid and compared with the results for steady flow. The invasive (with guidewire insertion) and non-invasive (without guidewire insertion) pressure and flows are measured simultaneously. The experimental data is presented in the form of axial pressure drop, distal pressure recovery (pressure recovery and pressure drop coefficients) and pressure drop-flow characteristics. Based on previous numerical work [Banerjee et al 2000, 2003], the experimental data is validated numerically. Finally, the guidewire flow obstruction effect on clinical parameters (FFR and CFR) is quantified and compared with in-vivo data [Takayama et al. 2001].
School:University of Cincinnati
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:coronary stenosis guidewire diagnosis ffr cfr steady and pulsatile flow pressure drop coefficient diffuser performance
Date of Publication:01/01/2006