title: Incremental value of coronary flow velocity reserve, measured by transthoracic echocardiography, compared with computed tomography angiography alone, for detecting flow-limiting coronary stenoses.
abstract: BACKGROUND
  Computed tomographic (CT) angiography provides high sensitivity for the detection of coronary stenosis, while its specificity is relatively low. The aim of this study was to determine the incremental value of coronary flow velocity reserve (CFVR) by transthoracic echocardiography when used with CT angiography for detecting stenosis of the major coronary arteries compared with invasive quantitative coronary angiography.
  
  
  METHODS
  Sixty patients who underwent CFVR measurement before coronary angiography were retrospectively selected, and the cutoff value of CFVR to predict diameter stenosis > 70% was determined using receiver operating characteristic curve analysis. Second, CFVR measurement and CT angiography were prospectively performed in 50 patients who were scheduled to undergo coronary angiography. CT angiography using a 64-detector row scanner and CFVR measurement in the proximal to middle portions of the three major coronary arteries by transthoracic echocardiography were performed on the same day, <48 hours before invasive angiography.
  
  
  RESULTS
  The cutoff values of CFVR were determined to be 2.0 for the left anterior descending coronary artery and 2.1 for the circumflex and right coronary arteries. Using these determined cutoff values, the sensitivity, specificity, and positive and negative predictive value of CFVR to identify diameter stenosis ≥ 70% stenosis on invasive quantitative coronary angiography were determined to be 84%, 87%, 66%, and 95%, respectively, and those of CT angiography were 91%, 80%, 58%, and 97%, respectively, in the prospective study with 50 patients. The combination of ≥70% stenosis on CT angiography and impaired CFVR was 94% specific for ≥70% stenosis, while the presence of <70% stenosis on CT angiography and preserved CFVR was 100% specific for the exclusion of ≥70% stenosis on invasive quantitative coronary angiography.
  
  
  CONCLUSIONS
  When the results of CT angiography and CFVR are concordant, the combination is highly accurate in the detection and exclusion of coronary stenosis. CFVR measurement in addition to CT angiography could be helpful in identifying false-positive CT angiographic results.
authors.affiliation: Department of Cardiology, Wakayama Medical University, Wakayama, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Nakanishi
authors.affiliation: Department of Cardiology, Wakayama Medical University, Wakayama, Japan. Electronic address: kumikohirata@aol.com.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Hirata
authors.affiliation: Department of Cardiology, Wakayama Medical University, Wakayama, Japan.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Tsujioka
authors.affiliation: Department of Cardiology, Wakayama Medical University, Wakayama, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamano
authors.affiliation: Department of Cardiology, Wakayama Medical University, Wakayama, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Tanimoto
authors.affiliation: Department of Cardiology, Wakayama Medical University, Wakayama, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Ino
authors.affiliation: Department of Cardiology, Wakayama Medical University, Wakayama, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Yamaguchi
authors.affiliation: Wakayama-South Radiology Clinic, Wakayama, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Shimamoto
authors.affiliation: Department of Cardiology, Wakayama Medical University, Wakayama, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kubo
authors.affiliation: Department of Cardiology, Wakayama Medical University, Wakayama, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tanaka
authors.affiliation: Department of Cardiology, Wakayama Medical University, Wakayama, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Imanishi
authors.affiliation: Wakayama-South Radiology Clinic, Wakayama, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Terada
authors.affiliation: Department of Cardiology, Wakayama Medical University, Wakayama, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Akasaka
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity; D017023:Coronary Angiography / Q000379:methods*; D003326:Coronary Circulation; D023921:Coronary Stenosis / Q000175:diagnosis* / Q000503:physiopathology*; D004452:Echocardiography / Q000379:methods*; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D008297:Male; D064847:Multimodal Imaging / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Coronary computed tomography; Coronary flow velocity reserve; Echocardiography