Serial intravascular ultrasound analysis of the main and side branches in bifurcation lesions treated with the T-stenting technique.

OBJECTIVES This study sought to investigate the mechanism of restenosis and the predictive value of post-procedural minimum stent area (MSA) in the side branch (SB) after coronary bifurcation stenting. BACKGROUND The mechanism of restenosis, especially at the SB ostium, has not been fully elucidated. METHODS This study examined 73 bifurcation lesions with post-procedural and 9-month follow-up intravascular ultrasound images for both main vessel (MV) and SB. All lesions were treated with drug-eluting stents using the T-stenting technique. Analysis included 5 distinct locations: MV proximal stent, MV middle area, MV distal stent, SB ostium (<5 mm distal to the neocarina), and SB distal stent. RESULTS Stent expansion was significantly less in the SB than in the MV (87.1 +/- 20.4% vs. 97.0 +/- 29.1%, p = 0.007). The SB ostium was the most frequent site of post-procedural MSA. At the SB ostium, follow-up minimum lumen area (MLA) correlated with post-procedural MSA (r = 0.81, p < 0.001). The percentage of neointimal area was higher at the SB ostium than at the MV proximal, MV distal, and SB distal stent (23.8 +/- 18.9% vs. 13.3 +/- 17.3%, 15.4 +/- 20.5%, and 12.5 +/- 17.2%, p < 0.001). The optimal threshold of post-procedural MSA to predict follow-up MLA > or =4 mm(2) at the SB ostium was 4.83 mm(2), yielding an area under the curve of 0.88 (95% confidence interval: 0.80 to 0.95). CONCLUSIONS Our data suggest that inadequate post-procedural MSA with increased neointimal hyperplasia may cause the SB ostium to be the most frequent site of restenosis after percutaneous coronary intervention on bifurcation lesions.