Neointimal coverage on drug-eluting stent struts crossing side-branch vessels using optical coherence tomography

The status of neointimal coverage on the drug-eluting stent (DES) struts, which are placed across the side-branch vessels, remains unclear. The degree of neointimal coverage of stent struts crossing the side-branch vessel was evaluated according to the different types of DESs. Follow-up optical coherence tomography images at 9.3 months after the index procedure were identified in 51 patients who had undergone DES (sirolimus-eluting stents [SESs] in 22 patients, paclitaxel-eluting stents [PESs] in 15, and zotarolimus-eluting stents [ZESs] in 14) implantation with crossover of the side-branch vessels (size >2.0 mm). The enrolled patients were classified as a covered group if every unapposed strut showed neointimal coverage or an uncovered group if any struts lacked neointimal coverage. The neointimal hyperplasia thickness was also measured. The number of patients in the covered group was 15 (29%), with 36 patients in the uncovered group. Significant differences were found in the proportion of the covered group among the 3 DES types (6 [27%] of 22 with SESs, 1 [7%] of 15 with PESs, and 8 [57%] of 14 with ZESs; p = 0.011). The percentage of neointimal coverage in the overall stent struts was also significantly different among the 3 DES types (65% of 356 struts, 20% of 165 struts, and 83% of 143 struts for the SESs, PESs, and ZESs, respectively; p<0.001). The neointimal hyperplasia thickness in the PES group was significantly smaller than those of the ZES and SES groups (0.02 +/- 0.02 mm vs 0.08 +/- 0.06 mm and 0.04 +/- 0.03 mm, respectively; p = 0.002). In conclusion, different patterns of neointimal coverage of the stent struts crossing the side branch vessels were observed according to the type of DES.