title: Serial intravascular ultrasound observations from the Tryton first-in-man study.
abstract: OBJECTIVE
  To report serial intravascular ultrasound (IVUS) findings of bifurcation lesions treated with the dedicated Tryton Side Branch Stent to assess mechanisms of restenosis.
  
  
  RESULTS
  The Tryton FIM study was a multicentre, prospective, single-arm, "first-in-man" study to treat de novo bifurcation lesions. Minimum lumen area (MLA) sites and overall volumes were analysed within main vessels and side branches. Overall, 27 main vessels and 22 side branches had paired baseline and follow-up IVUS. The post-intervention main vessel MLA decreased from 5.3 (4.1, 6.2) to 4.8 (3.4, 5.7) mm2 at follow-up, p=0.02, and the side branch MLA decreased from 3.5 (3.0, 3.8) to 2.5 (2.2, 3.2) mm2, p=0.0005. Stent area at the side branch did not change (mean stent area from 4.0 [3.3, 4.1] to 3.8 [3.4, 4.2] mm3/mm, p=0.95). Neointimal hyperplasia (NIH) net volume obstruction (%) measured 1.8% (0.5, 7.0) for the entire main vessel and 14.9% (2.3, 31.1) for the entire side branch stents. In both main vessel and side branches the decrease in lumen area correlated significantly with NIH.
  
  
  CONCLUSIONS
  Serial IVUS analysis of a new side branch Tryton stent showed no chronic stent recoil. Side branch underexpansion was common and along with superimposed NIH contributed to the reduction in lumen dimensions at follow-up.
authors.affiliation: Cardiovascular Research Foundation, Columbia University Medical Center, New York, NY, USA.
authors.forename: Akiko
authors.initials: A
authors.lastname: Maehara
authors.forename: Robert Jan
authors.initials: RJ
authors.lastname: van Geuns
authors.forename: Yves
authors.initials: Y
authors.lastname: Louvard
authors.forename: Ralf
authors.initials: R
authors.lastname: Müller
authors.forename: Eberhard
authors.initials: E
authors.lastname: Grube
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Morice
authors.forename: H Richard
authors.initials: HR
authors.lastname: Davis
authors.forename: Aaron V
authors.initials: AV
authors.lastname: Kaplan
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Onuma
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Serruys
authors.forename: Gary S
authors.initials: GS
authors.lastname: Mintz
mesh_terms: D017023:Coronary Angiography / Q000379:methods; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000628:therapy; D023903:Coronary Restenosis / Q000000981:diagnostic imaging* / Q000628:therapy; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015607:Stents; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional