Relationship between stent malapposition and incomplete neointimal coverage after drug-eluting stent implantation

Using optical coherence tomography (OCT), we evaluated the relationship between malapposed and uncovered struts following implantation of drug-eluting stents (DESs).

A total of 271 patients with 306 lesions who underwent DES implantation and follow-up OCT were included in the study. The lesions were grouped based on the presence of malapposition and then by the median value of the percentage of malapposed struts (1.3%) to produce 3 groups: lesions without malapposition (group I, n = 232) and those with percentage of malapposed struts <1.3% (group II, n = 37) or ≥1.3% (group III, n = 37). Percentages of malapposed and uncovered struts were calculated as percent ratio of malapposed or uncovered to total struts in the defined cross-sections, respectively. We compared percentage of uncovered struts in all analyzable struts and in the residual struts without malapposed segments among the 3 groups.

Group III showed a significantly larger percentage of uncovered struts among all the struts (group I, 3.7 ± 6.4 vs. II, 5.5 ± 5.6 vs. III, 17.6 ± 15.9%, P < 0.001) and among residual struts without malapposed segments (3.7 ± 6.4 vs. 5.2 ± 5.7 vs. 15.0 ± 14.4%, respectively, P < 0.001). There was a significant correlation between malapposed and uncovered struts in group III (r = 0.393, P = 0.016), but not in group II (r =-0.007, P = 0.965) among residual struts without malapposed segments.

The percentage of uncovered DES struts was quite different depending on the presence and extent of malapposed struts.