CORRECTION TO FLOW-RATE - PRESSURE-DROP RELATION IN CORONARY ANGIOPLASTY - STEADY STREAMING EFFECT

The changed flow pattern of pulsatile brood flow in a catheterized ste nosed artery has been studied through a mathematical model. The study takes into account the effect of the movement of the flexible catheter influenced by the pulsatile nature of the flow. The contribution of t he steady streaming effect brings into focus the existence of a non-ze ro mean pressure drop in addition to the one predicted by the linear t heory - a fact overlooked by the previous authors. Thus our results ar e intended to provide a correction to the mean pressure drop usually c alculated by neglecting the non-linear inertia terms. The calculations based on the geometry and the flow conditions representing a real phy siological situation as closely as possible suggest that depending upo n the values of k (where k is the ratio of the catheter size to vessel size) ranging from 0.2 to 0.5 mean pressure drop increases for any fr equency parameter. In addition, it is found that depending upon the ma terial properties, a thin catheter experiencing small oscillations due to the flow conditions is likely to influence in the same way as a th icker catheter which remains fairly stationary inside the artery. The results are sensitive to the shape of the wall geometry and will be di fferent for different wall geometries even if the cross-sectional area reduction at the peak of stenosis is kept the same. Interesting strea mline patterns depict distinct boundary layer characteristics both at the artery wall and catheter wall. Finally, the effect of catheterizat ion and its movement on various physiologically important flow charact eristics-mean pressure drop, impedance, wall stress is studied for dif ferent range of catheter size and frequency parameter. (C) 1998 Elsevi er Science Ltd. All rights reserved.