Excessive intrastent plaque volume is the major cause of restenosis after intracoronary bare metal stent implantation: a 3-dimensional intravascular ultrasound and quantitative coronary angiography based study.

ABSTRACT

Vascular response after percutaneous coronary intervention (PCI) may differ in different ethnic group. Here we show the impact of peri-stent and intra-stent remodeling on coronary stenotic lesions in a group of Japanese patients. Those lesions were evaluated before, after and during follow up, with 3 dimensional intravascular ultrasound (IVUS) (3-D IVUS) and quantitative coronary angiography (QCA) 30 patients with pre, post and follow up IVUS were enrolled. Quantitative data are presented as the mean +/- SD, and categorical data as frequencies. Binary variables were compared with Mann Whitney's U test. There were 7 cases with restenosis (RS) and 23 cases with no-restenosis (NR). In QCA based evaluation, minimum lumen diameter (1.2 +/- 0.4 mm vs. 2.4 +/- 0.6 mm, p < 0.001) and % diameter stenosis (59.1+/- 16.1 vs. 23.3 +/- 16.1, p < 0.001) were significantly reduced in RS at follow up. Acute gain was similar among both groups (RS; 2.1 +/- 0.6 mm vs. NS; 2.2 +/- 0.7 mm, p = 0.5), however, late loss was significantly increased in RS (2.1 +/- 0.8 vs. 0.8 +/- 0.5, p < 0.001). At 3-D IVUS based follow up, lumen volume index was significantly reduced in RS (3.6 +/- 0.8 mm3/mm vs. 6.9 +/- 0.8 mm3/mm, p < 0.01). There was higher intrastent plaque volume index in RS in comparison to NR (5.4 +/- 1.4 mm3/mm vs. 3.1+/- 1.1 mm3/mm, p < 0.05). Linear regression analysis showed a tendency for a significant inverse correlation between the percentage of delta peristent volume index and the percentage of delta intrastent volume index (R2 = 0.12, p = 0.054). The intrastent plaque growth is the major player in causing restenosis.