Optical coherence tomography-based evaluation of malapposed strut coverage after drug-eluting stent implantation

Minimal data exist regarding the use of optical coherence tomography (OCT) to evaluate malapposed strut coverage following implantation of drug-eluting stents (DESs). Follow-up OCT examination after DES implantation was performed in 368 patients with 406 lesions at our institute. We assessed the status of malapposed strut coverage that was identified via OCT in 92 (23 %) lesions. An absence of uncovered struts among malapposed struts was defined as completely covered (CC) malapposition; the presence of uncovered struts was defined as incompletely covered (IC) malapposition. Among the 92 lesions with malapposed DES struts, CC malapposition was detected in 47 lesions (51 %). Compared to lesions with IC malapposition (n = 45, 49 %), lesions with CC malapposition showed a significantly lower percentage of uncovered struts among all the struts (14.9 +/- 14.5 vs. 4.4 +/- 8.5 %, respectively, p < 0.001) and among the other well-apposed struts without malapposition (12.7 +/- 12.8 vs. 4.5 +/- 8.7 %, respectively, p = 0.001). The degree of malapposed strut coverage was significantly different according to the type of DES; new-generation DESs such as everolimus- or zotarolimus-eluting stents showed a higher incidence of CC malapposition, compared to first-generation DESs such as sirolimus- or paclitaxel-eluting stents (82 vs. 34 %, respectively, p < 0.001). This study showed the complete coverage in about 50 % of the lesions with malapposed DES struts on follow-up OCT. The degree of malapposed DES strut coverage was strongly affected by the type of implanted DESs.