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 ≥4 mm² at the SB ostium was 4.83 mm², 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.