Abstract 14937: Impact of Myocardial Bridging on Stent-edge Compression in Left Anterior Descending Coronary Arteries
Background: In clinical settings, stent implantation under myocardial bridging (MB) does not always lead to chronic stent recoil. This study aimed to evaluate the mechanical stent response to MB in relation to the relative positioning and the severity of arterial compression.
Methods: Serial (baseline and 8 months) IVUS was performed in 321 LAD lesions treated with a drug-eluting stent. Significant chronic stent recoil was defined as >10% decrease in stent volume during follow-up. Geography of stent recoil was evaluated by dividing the stent into 3 subsegments: proximal 5-mm, mid-body, and distal 5-mm. MB was identified as an echolucent muscle band partially surrounding the artery. At a non-stented segment, arterial compression by MB was quantified as a decrease in vessel area at systole standardized by vessel area at end-diastole (%).
Results: MB was identified in 93 patients, 45.1% of which had the distal stent segment located under the MB (stent-in-MB). Compared with non-MB patients as a control group, the incidence of chronic recoil was significantly higher in the stent-in-MB patients, particularly at the distal stent segment (left figure). The degree of stent recoil (decrease in stent volume) positively correlated with the degree of arterial compression, both at the mid-body (p<0.0001) and distal stent segment (p<0.0001, right figure). ROC analysis determined arterial compression of 14.5% to best predict subsequent significant chronic stent recoil at the distal segment (sensitivity=90.0%, specificity=75.0%, AUC=0.850). In contrast, patients with a stent implanted outside the MB showed equivalent chronic recoil to the control, demonstrating no correlation with arterial compression or distance to the MB entrance.
Conclusion: Both relative stent positioning and arterial compression determine chronic stent recoil. Stenting into the tunneled segment may result in significant chronic recoil, particularly when arterial compression measures 15% or greater.
Author Disclosures: S. Tanaka: None. R. Yamada: None. Y. Kobayashi: None. K. Okada: None. K. Otagiri: None. H. Kitahara: None. P.G. Yock: None. P.J. Fitzgerald: None. Y. Honda: None.
- © 2014 by American Heart Association, Inc.