Abstract 3786: The Virtual Histology Intravascular Ultrasound Appearance of Newly-Placed Drug-Eluting Stents: Implications for Follow-up Analyses
Background. Intravascular ultrasound (IVUS) is used pre and post-intervention and at follow-up. IVUS Virtual Histology (VH) classifies tissue into fibrous, fibrofatty, dense calcium, and necrotic core. Although most interventional procedures include stent implantation, VH IVUS classification of stent metal is unvalidated. There is intense interest in peri-strut findings in drug-eluting stents (DES) including positive remodeling, inflammation from the polymer, incomplete healing, etc
Methods and Results. We report VH IVUS appearances of acutely implanted DES in 27 pts (30 lesions). Most (80.3%) stent struts appeared as white (misclassified as “calcium”) surrounded by red (misclassified as “necrotic core”) (Figure⇓) while 2.3% appeared just white and 17.4 % were not detectable (when compared to grey scale IVUS). The rate of “white surrounded by red” was similar over the length of the stent; however, undetectable struts were mostly at the distal edge (30.6%). Most importantly, the fact that 80.3% of acutely implanted stent struts were surrounded by a red “halo” that looked like a necrotic core meant that this was an artifact and that the “red halo” should not be interpreted as peri-strut inflammation or necrotic core when seen at follow-up.
Conclusion: Acutely implanted DES have an appearance that can be misclassified by VH IVUS as “calcium±necrotic core”. It is important not to overinterpret VH IVUS studies of chronically implanted DES when a similar appearance is observed at follow-up. Separate classification for stent struts is necessary in order to avoid these misconceptions/misclassifications.