Results From the MISSION! Intervention Study Sirolimus-Eluting Stents Vs Bare-Metal Stents in Patients With STEMI : 9-Month Angiographic and Intravascular Ultrasound Results and 12-Month Clinical Outcome Bas L. van der Hoeven, MD,* Su-San Liem, MD,* J. Wouter Jukema, MD, PHD,* Navin Suraphakdee, MD,* Hein Putter, MSC, PHD,† Jouke Dijkstra, MSC, PHD,‡ Douwe E. Atsma, MD, PHD,* Marianne Bootsma, MD, PHD,* Katja Zeppenfeld, MD, PHD,* Pranobe V. Oemrawsingh, MD, PHD,* Ernst E. van der Wall, MD, PHD,* Martin J. Schalij, MD, PHD* R3 Lee Jae Yeon Journal of the American College of Cardiology Vol. 51, No. 6, 2008

Background  Stent thrombosis occurring late after implantation of drug- eluting stents, possibly related to” late malapposition of the stent struts” has raised safety concerns  evaluate midterm angiographic outcome and clinical efficacy of 3rd-generation BMS vs sirolimus-eluting stents (SES) in STEMI  To address the issue of late stent malapposition(LSM),  intravascular ultrasound (IVUS) imaging (in both, at 9-month f/u)

Methods  single-blind, single-center, randomized prospective study  Patient  Exclusion criteria STEMI : ST-segment elevation ≥0.2 mV in ≥ 2 contiguous leads in V1 ~3 or ≥ 0.1 mV in other leads, or [presumed] new LBBB Sx onset < 9 h before PCI Target lesion length ≤ 24 mm 1) age 80 years 2) left main stenosis of ≥ 50% 3) triple-vessel disease, defined as ≥ 50% stenosis in ≥ 3 major epicardial br. 4) previous PCI or CABG of the infarct-related artery 5) thrombolytic therapy for the index infarction 6) target vessel reference diameter 3.75 mm 7) need for mechanical ventilation 8) CIx to the use of aspirin, clopidogrel, heparin,or abciximab 9) known renal failure 10) a life expectancy < 12 month

Methods  Quantitative coronary angiography (QCA) and IVUS analysis Late luminal loss (LLL) : difference between the post-procedural MLD & f/u MLD Angiographic restenosis : ≥ 50% diameter stenosis at 9-months, f/u Stent malapposition : - separation of ≥ 1 stent strut, not overlapping a side branch, - from the intimal surface with IVUS evidence of blood speckles behind the strut

 Study end point Primary end point - in-segment late luminal loss(LLL) at 9 months Secondary end points - late stent malapposition (LSM) at 9 months as determined by IVUS - clinical events at 12 months

Results

Discussion In-segment LLL in the SES group was comparable to the LLL found in the angiographic subgroup of the recently published TYPHOON (Trial to Assess the Use of the Cypher Stent in Acute Myocardial Infarction Treated With Angioplasty) Significant rate of LSM (37.5%) was observed in the SES group The majority of these malappositions was not present immediately after implantation but developed during follow-up, predominantly along the body of the stent (20.2%)

 Possible cause of Late stent malapposition 1) insufficient stent deployment during implantation 2) resolution of thrombus and/or plaque behind the stent 3) positive remodeling of the vessel wall

Conclusions  The SES implantation in STEMI patients is associated with superior midterm clinical and angiographic results compared with BMS implantation  LSM is frequently observed in STEMI patients treated with SES, raising concern about long-term safety warranting longterm clinical follow-up Therefore, based on this study, we cannot recommend or discourage SES use in STEMI patients