[Evaluation of the late stent malposition after drug-eluting stent implantation by optical coherence tomography].

Objective: To evaluate the characteristic of late stent malposition after drug-eluting stent implantation by optical coherence tomography (OCT).

Methods: The study comprised of 32 patients (target vessels: 51, total stents: 71) underwent drug eluting stent implantation one year ago [average (14.8 +/- 5.2) months]. OCT images of the stent were analyzed at interval of 0.5 mm. The stent malposition was detected, the thickness of intima and gap between the stent strut and vessel wall were measured.

Results: Stent malposition was detected in 7 patients without clinical cardiac events, including positive remodeling (n = 4), overlapping stents (n = 1) and stent struts covered with thrombus (n = 2). Stent strut apposition with complete intima coverage was about 97.6%, stent struts malposition was 2.4% including half of struts located at the ostium of side branch. The intima coverage of stent struts is similar between the struts at the side branch and others [(0.06 +/- 0.05) mm vs. (0.05 +/- 0.03) mm, P > 0.05].

Conclusion: The causes of late stent malposition include the primary malposition after stent implantation, positive remodeling, overlapping stents and stent struts located at the ostium of side branch. Thinner intima coverage was also observed on the stent struts with malposition.