title: Non-invasive computed fractional flow reserve from computed tomography (CT) for diagnosing coronary artery disease – Japanese results from NXT trial (Analysis of Coronary Blood Flow Using CT Angiography: Next Steps).
abstract: BACKGROUND
  Recently, a non-invasive method using computational fluid dynamics to calculate vessel-specific fractional flow reserve (FFRCT) from routinely acquired coronary computed tomography angiography (CTA) was described. The Analysis of Coronary Blood Flow Using CT Angiography: Next Steps (NXT) trial, which was a prospective, multicenter trial including 254 patients with suspected coronary artery disease, noted high diagnostic performance of FFRCT compared with invasive FFR. The aim of this post-hoc analysis was to assess the diagnostic performance of non-invasive FFRCT vs. standard stenosis quantification on coronary CTA in the Japanese subset of the NXT trial.
  
  
  RESULTS
  A total of 57 Japanese participants were included from Okayama University (n=36), Kyoto University (n=17), and Keio University (n=4) Hospitals. Per-patient diagnostic accuracy of FFRCT(74%; 95% confidence interval [CI]: 60-85%) was higher than for coronary CTA (47%; 95% CI: 34-61%, P<0.001) arising from improved specificity (63% vs. 27%, P<0.001). FFRCT correctly reclassified 53% of patients and 63% of vessels with coronary CTA false positives as true negatives. When patients with Agatston score >1,000 were excluded, per-patient accuracy of FFRCT was 83% with a high specificity of 76%, similar to the overall NXT trial findings.
  
  
  CONCLUSIONS
  FFRCT has high diagnostic performance compared with invasive FFR in the Japanese subset of patients in the NXT trial.
authors.affiliation: Department of Cardiovascular Medicine, Okayama University Hospital, Japan. miyoshit@cc.okayama-u.ac.jp
authors.forename: Toru
authors.initials: T
authors.lastname: Miyoshi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Osawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ito
authors.forename: Susumu
authors.initials: S
authors.lastname: Kanazawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kimura
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shiomi
authors.forename: Sachio
authors.initials: S
authors.lastname: Kuribayashi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Jinzaki
authors.forename: Akio
authors.initials: A
authors.lastname: Kawamura
authors.forename: Hiram
authors.initials: H
authors.lastname: Bezerra
authors.forename: Stephan
authors.initials: S
authors.lastname: Achenbach
authors.forename: Bjarne L
authors.initials: BL
authors.lastname: Nørgaard
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*