[The impact of expansion of sirolimus eluting stent on intimal hyperplasia: an intravascular ultrasound study].

OBJECTIVE: To assess the impact of expansion grade of sirolimus eluting stent on intimal hyperplasia with intravascular ultrasound (IVUS). METHODS: A total of 75 patients implanted with sirolimus eluting stents for at least 8 months were enrolled in this study and IVUS could be performed in 76 stents of 73 patients and 2 patients were excluded due to total coronary occlusion. External elastic membrane (EEM) cross-sectional areas (CSA) at stent inlet and outlet, at in-stent minimal CSA; in-stent CSA, cavity CSA, intimal area (in-stent area-cavity area), maximal and minimal diameter of stent, and symmetry index of stent (minimal diameter of stent/maximal diameter of stent) were measured. RESULT: Five out of 76 stents of 73 patients developed intimal hyperplasia and intimal proliferation was inhibited by sirolimus eluting stent in patients with either minimal stent CSA/EEM CSA < 0.5 (n = 56) or >or= 0.5 (n = 20), minimal stent CSA/reference CSA < 0.9 (n = 44) or >or= 0.9 (n = 32), minimal stent CSA < 5 mm(2) (n = 25) or CSA >or= 5 mm(2) (n = 51), symmetry index of stent at minimal CSA of stent < 0.9 (n = 37) or >or= 0.9 (n = 39) during IVUS follow up. CONCLUSION: Sirolimus eluting stent inhibited intimal hyperplasia independent of stent expansion grade.