Estimation of increased flow resistance in a narrow catheterized artery--a theoretical model. J Biomech 1996 Jul;29(7):917-30
Date
07/01/1996Pubmed ID
8809622DOI
10.1016/0021-9290(95)00153-0Scopus ID
2-s2.0-0030199797 (requires institutional sign-in at Scopus site) 82 CitationsAbstract
The changed flow pattern in a narrow catheterized artery is studied and an estimate of the increased flow resistance is made. The anomalous behaviour of blood in small blood vessels has been taken into account by modelling blood as a Casson fluid possessing some finite yield stress. Both the cases of steady and pulsatile flow situations are studied. The pulsatile flow is analysed by considering the pressure gradient as a periodic function of time with small inertial effects. The resulting quasi-steady non-linear coupled implicit system of differential equations governing the flow are solved using a perturbation analysis, where it is assumed that the Womersley frequently parameter is small (alpha < 1) which is reasonable for physiological situations in small blood vessels as well as in coronary arteries. The effect of pulsatility, catheter radius and yield stress of the fluid on the yield plane locations, velocity distribution, flow rate, shear stress and frictional resistance are investigated. Because of the yield stress theta, two yield surfaces are found to be located in the flow field. Depending on the ration kappa (catheter size/vessel size) ranging from 0.3 to 0.7 (which is widely used in coronary angioplasty procedures), the frictional resistance to flow in large blood vessels, where the effect of yield stress can be neglected (i.e. theta = 0), increases by a factory ranging from 3 to 33. In small blood vessels with the same range of catheter size and an unit pressure gradient, frictional resistance increase was by a factor of 7-21 when theta = 0.05 and 11-294 when theta = 0.1. For small values of kappa and theta, the frictional resistance increased to several hundred times thus implying that the combined effect of increased catheter radius and yield stress is to obstruct the fluid movement considerably.
Author List
Dash RK, Jayaraman G, Mehta KNAuthor
Ranjan K. Dash PhD Professor in the Biomedical Engineering department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AnimalsArteries
Catheterization
Humans
Models, Cardiovascular
Regional Blood Flow
Stress, Mechanical
Vascular Resistance