Physiological flow simulation in residual human stenoses after coronary angioplasty

To evaluate the local hemodynamic implications of coronary artery balloon a ngioplasty computational fluid dynamics (CFD) was applied in a group Of pat ients previously reported by [Wilson et al. (1988), 77, pp. 873-885] with r epresentative stenosis geometry post-angioplasty and with measured values o f coronary flow reserve returning to a normal range (3.6+/-0.3). During und isturbed flow in the absence of diagnostic catheter sensors within the lesi ons the computed mean pressure drop Delta(p) over tilde was only about 1 mm Hg at basal flow and increased moderately to about 8 mmHg for hyperemic flo w. Corresponding elevated levels of mean wall shear stress in the midthroat region of the residual stenoses, which are common after angioplasty proced ures, increased from about 60 to 290 dynes/cm(2) during hyperemia. The comp utations ((R) over bare(e) similar or equal to 100-400; alpha (e) = 2.25) i ndicated that the pulsatile flow field was principally quasi-steady during the cardiac cycle but there was phase lag in the pressure drop-mean velocit y (Deltap - (u) over bar) relation. Time-averaged pressure drop values, Del ta(p) over tilde, were about 20 percent higher than calculated pressure dro p values, Deltap(s), for steady flow, similar to previous in vitro measurem ents by Cho et al. (1983). In the throat region, viscous effects were confi ned to the near-wall region and entrance effects were evident during the ca rdiac cycle. Proximal to the lesion, velocity profiles deviated from parabo lic shape at lower velocities during the cardiac cycle. The flow field was very complex in the oscillatory separated flow reattachment region in the d istal vessel where pressure recovery occurred These results may also serve as a useful reference against catheter-measured pressure drops and velocity ratios (hemodynamic endpoints) and arteriographic (anatomic) endpoints pos t-angioplasty. Some comparisons to previous studies of flow through stenose s models are also shown for perspective purposes. [S0148-0731(00)00304-6].