Poststenting axial redistribution of atherosclerotic plaque into the reference segments and lumen reduction at the stent edge - A volumetric intravascular ultrasound study

Lumen enlargement during coronary stenting results from vessel expansion and axial redistribution of atheromatous plaque along the stented segment and proximal and distal reference segments. Plaque burden predicts stenosis at the stent edge. The aim of this study was to investigate the fate of shifted plaque with special reference to whether or not plaque shift (PSh) correlates with late lumen reduction. This is a prospective study conducted on 54 consecutive patients who underwent bare metal stenting. In all stent edges (108 edges), PSh volume was measured as post intervention plaque-media volume (PMV) minus preintervention PMV. Changes in lumen volume (Delta LV), vessel volume (Delta VV), and PMV (Delta PMV) were measured by serial intravascular ultrasound (IVUS) examination. After stenting, PSh was detected in 81.5% of proximal edges versus 72.2% of distal edges (P = 0.36). It correlated significantly with Delta VV (r = 0.34, P = 0.002), and inversely with Delta LV (r = 0.32, P = 0.003). However, at 6-month follow-Lip, it did not correlate with ALV (r = -0.03, P = 0.8), Delta VV (r = 0.1, P = 0.6), or Delta PMV (r = 0.1. P = 0.4). Furthermore, ALV correlated more strongly with Delta VV (r = 0.62, P < 0.00001) than with Delta PMV (r = -0.39, P = 0.001). By multivariate analysis, PSh area was an independent predictor of the postintervention change in lumen area (partial eta squared 0.21, P = 0.01), but not the follow-up change. Two patients (3.7%) developed proximal edge stenosis with no evident PSh after stenting. Thus, axial redistribution of atheromatous plaque into the reference segments was frequently encountered after stenting. Although PSh correlated with the immediate reduction in stent edge lumen volume, it did not correlate with the late lumen reduction.