title: Calcified plaque rupture and very late stent thrombosis after bare-metal stent implantation.
abstract: Very late stent thrombosis (>1 year: VLST) is a major concern in the drug-eluting stent (DES) era. VLST occurs not only in patients implanted with DESs but also in those implanted with bare-metal stents (BMSs). We examined intravascular ultrasound (IVUS) findings in patients with VLST after BMS implantation. Five consecutive patients presented with VLST as ST elevation myocardial infarction. VLST occurred at a mean of 9.5 years after BMS implantation. In the IVUS findings, the minimum stent area was 7.8 ± 1.2 mm(2). None of the patients had incomplete stent apposition or stent underexpansion, which was defined as a stent expansion index of <0.8. The mean stent expansion index was 1.01. Calcium deposits in the previous stented segment were observed in 4 patients (80%), and a total of 14 calcium deposits were observed in all patients. The calcification pattern was superficial (78.5%) and spotty (57.1%) within a calcium arc of <90°. The mean calcium arc was 72.5° ± 88.5°. A ruptured plaque with an intraluminal flap was detected in all cases. According to the IVUS findings of ruptured plaque and calcium deposits, VLST after BMS might be caused by a thrombus formation subsequent to a calcified atherosclerotic plaque rupture.
authors.affiliation: Department of Cardiology, Yokohama Rosai Hospital, 3211 Kozukue-cho, Kohoku-ku, Yokohama, Kanagawa, Japan, kyumoto@db3.so-net.ne.jp.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Yumoto
authors.forename: Tagayasu
authors.initials: T
authors.lastname: Anzai
authors.forename: Hajime
authors.initials: H
authors.lastname: Aoki
authors.forename: Akira
authors.initials: A
authors.lastname: Inoue
authors.forename: Shuhei
authors.initials: S
authors.lastname: Funada
authors.forename: Hiroki
authors.initials: H
authors.lastname: Nishiyama
authors.forename: Shingo
authors.initials: S
authors.lastname: Tanaka
authors.forename: Shinya
authors.initials: S
authors.lastname: Kowase
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Shirai
authors.forename: Kenji
authors.initials: K
authors.lastname: Kurosaki
authors.forename: Akihiko
authors.initials: A
authors.lastname: Nogami
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Daida
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kato