Effect of stenting on coronary flow velocity reserve: comparison of coil and tubular stents

ObjectiveTo determine whether coil stents are as effective as tubular stents in improving coronary flow velocity reserve (CFVR) after stent deployment. MethodsDistal CFVR was measured with a 0.014 inch Doppler guide wire before and after stenting in 33 patients. A coil stent was implanted in 16 patients and a tubular stent was used in 17 patients. Coronary flow velocity within the stent was also recorded during a slow pullback. ResultsFollowing placement of the stents, the percentage diameter stenosis was similar for both the tubular and coil stents (mean (SE) 11 (2)% v 13 (2)%, NS). However, distal CFVR was higher after stenting with a tubular stent compared with a coil stent (2.46 (0.13) v 1.96 (0.14), p < 0.05). Furthermore, pullback through the stent detected a major flow velocity increase within coil stents but not in tubular stents (83 (24)% v 5 (5)%, p < 0.05). ConclusionsIn spite of similar angiographic improvement, placement of coil stents was associated with inferior functional results compared with tubular stents. The flow velocity acceleration within the coil stents suggests the presence of a residual narrowing within the stent, which is not appreciated on angiography.