title: Incidence, mechanisms, predictors, and clinical impact of acute and late stent malapposition after primary intervention in patients with acute myocardial infarction: an intravascular ultrasound substudy of the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial.
abstract: BACKGROUND
  The incidence and mechanisms of acute and late stent malapposition after primary stent implantation in ST-segment elevation myocardial infarction remain unclear.
  
  
  RESULTS
  The Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial was a dual-arm, factorial, randomized trial comparing paclitaxel-eluting stents (PES) and otherwise equivalent bare metal stents (BMS) in ST-segment elevation myocardial infarction patients. The intravascular ultrasound substudy enrolled 241 patients with 263 native coronary lesions (201 PES, 62 BMS) with baseline and 13-month follow-up imaging. Postintervention acute stent malapposition (ASM) occurred in 34.3% PES- and 40.3% BMS-treated lesions. Of these, 39.1% PES- and 40.0% BMS-treated lesions resolved at follow-up, especially within the stent body (66.7%); complete resolution was accompanied by a reduction in external elastic membrane area. An ASM area >1.2 mm(2) best separated persistent from resolved ASM. At follow-up, a higher frequency of late stent malapposition was detected in PES-treated lesions (46.8%) mainly because of more late acquired stent malapposition (30.8%) compared with BMS-treated lesions. Late acquired stent malapposition area correlated to the decrease of peri-stent plaque in the subset of lesions without positive remodeling and only to change in external elastic membrane in the group with positive remodeling. Independent predictors of late acquired stent malapposition were plaque/thrombus protrusion (odds ratio, 5.60; 95% confidence interval [CI], 2.32 to 13.54) and PES use (odds ratio, 6.32; 95% CI, 2.15 to 18.62).
  
  
  CONCLUSIONS
  The incidence of ASM was similar in PES- and BMS-treated lesions, but late acquired stent malapposition was more common in PES-treated lesions. The reason for resolved ASM was negative remodeling, with larger ASM areas separating persistent from resolved ASM. Late acquired stent malapposition was due mainly to positive remodeling and plaque/thrombus resolution.
  
  
  BACKGROUND
  URL: http://www.clinicaltrials.gov. Unique identifier: NCT00433966.
authors.affiliation: Columbia University Medical Center and Cardiovascular Research Foundation, New York, NY, 10022, USA.
authors.forename: Ning
authors.initials: N
authors.lastname: Guo
authors.forename: Akiko
authors.initials: A
authors.lastname: Maehara
authors.forename: Gary S
authors.initials: GS
authors.lastname: Mintz
authors.forename: Yong
authors.initials: Y
authors.lastname: He
authors.forename: Kai
authors.initials: K
authors.lastname: Xu
authors.forename: Xiaofan
authors.initials: X
authors.lastname: Wu
authors.forename: Alexandra J
authors.initials: AJ
authors.lastname: Lansky
authors.forename: Bernhard
authors.initials: B
authors.lastname: Witzenbichler
authors.forename: Giulio
authors.initials: G
authors.lastname: Guagliumi
authors.forename: Bruce
authors.initials: B
authors.lastname: Brodie
authors.forename: Mirle A
authors.initials: MA
authors.lastname: Kellett
authors.forename: Ovidiu
authors.initials: O
authors.lastname: Dressler
authors.forename: Helen
authors.initials: H
authors.lastname: Parise
authors.forename: Roxana
authors.initials: R
authors.lastname: Mehran
authors.forename: Gregg W
authors.initials: GW
authors.lastname: Stone
mesh_terms: D000368:Aged; D054855:Drug-Eluting Stents / Q000009:adverse effects*; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy*; D009204:Myocardial Revascularization; D017239:Paclitaxel; D011446:Prospective Studies; D012307:Risk Factors; D015607:Stents / Q000009:adverse effects*; D013927:Thrombosis / Q000453:epidemiology; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional
chemical_list: D017239:Paclitaxel