title: Distal left circumflex coronary artery flow reserve recorded by transthoracic Doppler echocardiography: a comparison with Doppler-wire.
abstract: BACKGROUND
  Coronary flow reserve (CFR) recording by means of transthoracic echocardiography (TTDE) in all the main distal coronary arteries is a challenge for advanced echocardiography. Validation studies of TTDE versus Doppler-wire (DW) recordings are available for Left Anterior Descending artery (LAD) and the Posterior Descending coronary artery (PD), but lacking for the more technically challenging Left Circumflex coronary artery (LCx).
  
  
  OBJECTIVE
  To evaluate the reliability of TTDE in assessing CFR in LCx when compared to the intracoronary Doppler flow-wire gold standard.
  
  
  METHODS
  we evaluated 5 patients (age = 60 +/- 9 years, 5 males) on LCx by TTDE and invasive CFR assessment. TTDE recording was performed using a low-frequency probe, with a four-chamber as a guiding 2D view. The 2 tests were performed on different days and in random order within 48 hours in a blind fashion. Vasodilator stimulus was adenosine, intravenously (140 gamma/kg/min x 3-6 min) for TTDE and intracoronary (40 gamma bolus) for DW recordings.
  
  
  RESULTS
  CFR values on LCx ranged from 1.9 to 2.8 for DW, and from 2.0 to 3.0 for TTDE, with an overall correlation of R = 0,85 (p = 0,06); normal (CFR > 2.5) or abnormal (CFR < 2.5) value was concordantly identified by the 2 techniques in 4 out 5 cases (80%).
  
  
  CONCLUSIONS
  CFR of LCx artery can be obtained noninvasively with TTDE.
authors.affiliation: Department of Cardiovascular Disease-Echocardiography Unit-S, Filippo Neri Hospital, Rome, Italy. a.auriti@sanfilipponeri.roma.it
authors.forename: Antonio
authors.initials: A
authors.lastname: Auriti
authors.forename: Christian
authors.initials: C
authors.lastname: Pristipino
authors.forename: Cinzia
authors.initials: C
authors.lastname: Cianfrocca
authors.forename: Antonino
authors.initials: A
authors.lastname: Granatelli
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Guido
authors.forename: Francesco
authors.initials: F
authors.lastname: Pelliccia
authors.forename: Salvatore
authors.initials: S
authors.lastname: Greco
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Richichi
authors.forename: Massimo
authors.initials: M
authors.lastname: Santini
mesh_terms: D000368:Aged; D017023:Coronary Angiography; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000502:physiology* / Q000503:physiopathology; D004452:Echocardiography / Q000592:standards*; D006801:Humans; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000503:physiopathology; D018608:Ultrasonography, Doppler / Q000592:standards