title: Acceleration time of systolic coronary flow velocity to diagnose coronary stenosis in patients with microvascular dysfunction.
abstract: BACKGROUND
  The aim of this study was to test whether acceleration time of systolic coronary flow velocity could contribute to the diagnosis of coronary stenosis in patients with microvascular dysfunction, on the basis of the hypothesis that systolic coronary flow is less influenced by microvascular function because of compressed myocardium.
  
  
  METHODS
  Coronary flow velocity was assessed in the left anterior descending coronary artery during hyperemia with intravenous adenosine by echocardiography in 502 patients who were scheduled for coronary angiography because of coronary artery disease and significant valvular disease. Coronary flow velocity reserve (CFVR) and the percentage acceleration time (%AT), as the percentage of the time from the beginning to the peak of systolic coronary flow over systolic time during hyperemia, were calculated. The diagnostic ability of CFVR and %AT for angiographic coronary artery stenosis was then analyzed. As invasive substudies, fractional flow reserve and %AT by a dual-sensor (pressure and Doppler velocity) guidewire were measured simultaneously with %AT on transthoracic echocardiography (n = 14).
  
  
  RESULTS
  Patients with coronary stenosis had significantly lower CFVR (1.7 ± 0.4) and greater %AT (65 ± 9%) compared with those without stenosis (2.6 ± 0.6 and 50 ± 13%, respectively). Percentage acceleration time by Doppler echocardiography was in good agreement with %AT (r = 0.98) and fractional flow reserve (r = 0.74) invasively measured by dual-sensor guidewire. Cutoff values of CFVR and %AT were determined as 2.0 and 60% in receiver operating characteristic curve analysis. The sensitivity, specificity, and accuracy of CFVR to detect coronary stenosis were 71.1%, 77.3%, and 75.4%, while those of %AT were 83.4%, 71.8%, and 75.4%, respectively. In addition, %AT provided high accuracy to detect coronary stenosis, especially in patients with previous myocardial infarctions, valvular disease, and left ventricular hypertrophy (81.1%, 84.1%, and 73.4%, respectively).
  
  
  CONCLUSIONS
  The %AT of systolic coronary flow velocity is a promising marker to diagnose coronary stenosis in patients with microvascular dysfunction.
authors.affiliation: Department of Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Kazushi
authors.initials: K
authors.lastname: Takemoto
authors.affiliation: Department of Medicine, Wakayama Medical University, Wakayama, Japan. Electronic address: hiratakumiko@aol.com.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Hirata
authors.affiliation: Department of Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Nozomi
authors.initials: N
authors.lastname: Wada
authors.affiliation: Department of Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Yasutsugu
authors.initials: Y
authors.lastname: Shiono
authors.affiliation: Department of Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Komukai
authors.affiliation: Department of Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Tanimoto
authors.affiliation: Department of Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Ino
authors.affiliation: Department of Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Hironori
authors.initials: H
authors.lastname: Kitabata
authors.affiliation: Department of Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Shigeho
authors.initials: S
authors.lastname: Takarada
authors.affiliation: Department of Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Nakamura
authors.affiliation: Department of Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kubo
authors.affiliation: Department of Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tanaka
authors.affiliation: Department of Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Imanishi
authors.affiliation: Department of Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Akasaka
mesh_terms: D000255:Adenosine Triphosphate; D000328:Adult; D000368:Aged; D019540:Area Under Curve; D001783:Blood Flow Velocity; D017023:Coronary Angiography; D003326:Coronary Circulation; D023921:Coronary Stenosis / Q000150:complications* / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D004452:Echocardiography; D005260:Female; D006349:Heart Valve Diseases / Q000150:complications*; D006801:Humans; D006940:Hyperemia / Q000139:chemically induced / Q000150:complications; D017379:Hypertrophy, Left Ventricular / Q000150:complications; D008297:Male; D012372:ROC Curve; D013318:Stroke Volume; D013599:Systole
chemical_list: D000255:Adenosine Triphosphate
keywords: %AT; %DS; AS; AUC; Aortic stenosis; Area under the curve; CFVR; Coronary flow; Coronary flow velocity reserve; Echocardiography; FFR; Fractional flow reserve; LV; LVEF; LVH; Left ventricular; Left ventricular ejection fraction; Left ventricular hypertrophy; MI; Myocardial infarction; Percentage acceleration time; Percentage diameter stenosis; ROC; Receiver operating characteristic