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

Background: Using optical coherence tomography (OCT), we evaluated the relationship between malapposed and uncovered struts following implantation of drug‐eluting stents (DESs). Methods: 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. Results: 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. Conclusion: The percentage of uncovered DES struts was quite different depending on the presence and extent of malapposed struts. (J Interven Cardiol 2012;25:270–277)