Although first generation DES reduced instent restenosis, still remained the unsolved problems such as stent thrombosis and restenosis in the era of DES. Second generation DES had been developed to improve the biocompatibility of stent coating focused on polymer compared to first generation DES, so that second generation stents showed better outcomes compared with first generation DES. On the other hands, in third generation DES, further refinement of DES involved more flexible stent platform. Promus ElementTM (Everolimus eluting stent, Boston Scientific, Nastick, MA) and Resolute Integrity® (Zotarolimus eluting stent, Medtronic Vascular, Santa Rosa, CA) are the third generation drug eluting stents which are designed to increase flexibility. In previous randomized controlled studies, both of these stents have shown at least non-inferior angiographic and clinical outcomes compared to second generation DES. However, there is lack of data about comparison of angiographic and clinical outcomes between Promus ElementTM and Resolute Integrity®.
IVUS is one of the widely used intracoronary imaging devices to provide more reproducible and accurate information about coronary anatomy than angiography in current practice.8 Optimal stent expansion assessed by intravascular ultrasound (IVUS) has been reported as an important factor to prevent stent thrombosis or restenosis.9 Accordingly, there have been many studies to evaluate the procedural or clinical benefit of IVUS guided angioplasty. However, The clinical benefit of IVUS-guided angioplasty with stent implantation is still in a controversy. In the previous studies, IVUS-guided stent implantation showed positive or negative beneficial effect on clinical outcomes according to their study subjects. However, the stents used in the previous studies are less useful in current practice of cardiology and there is lack of data of 3rd generation DES, which have different stent profiles and outcomes with their predecessors.
Thus we would perform a prospective randomized study in order to compare the efficacy of IVUS-guided angioplasty with conventional angioplasty-guided procedure in the long coronary lesion. Our main hypothesis is IVUS-guided 3rd generation DES implantation in the long coronary lesions would have better clinical outcomes compared with conventional angiography-guided strategy. We also intend to assess the clinical outcomes after Promus ElementTM and Resolute Integrity® implantation.
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