title: Noninvasive assessment of coronary flow reserve in the left anterior descending artery by transthoracic echocardiography before and after stenting.
abstract: BACKGROUND
  Noninvasive assessment of coronary flow reserve in the left anterior descending artery (LAD) by transthoracic Doppler echocardiography (TTDE) has been already validated as a new method for determining the degree of stenosis over the proximal flow.
  
  
  OBJECTIVE
  The aim of the study is to determine, by TTDE, the feasibility and the value of the coronary flow reserve (CFR) (defined as the maximal increase in coronary blood flow above its basal pressure for a given perfusion pressure when coronary circulation is maximally dilated) in the mid-to-distal LAD before and after percutaneous angioplasty and to demonstrate the early recovery of microvascular tone immediately after stenting.
  
  
  METHODS
  The study population consisted of 36 patients with significant isolated LAD stenosis (70-90%) identified by coronary angiography. CFR was recorded in the mid-to-distal LAD at rest and during hyperemia obtained after adenosine intravenous infusion before and after stenting.
  
  
  RESULTS
  Adequate visualization of the LAD was obtained in 25 out of 36 patients (70%). At rest the mean CFR was 1.5132 +/- 0.33 (1.1-2.58). However, after stenting the mean CFR was significantly higher: 2.18 +/- 0.55 (1.3-3.8), with P <0.01.
  
  
  CONCLUSIONS
  CFR can be easily determined by TTE in approximately 70% of patients. Noninvasive Doppler echocardiography shows impaired CFR in patients with LAD disease. After stenting CFR is restored, demonstrating early recovery of microvascular tone. These results are comparable to those published in the same conditions. Larger series with a long-term follow-up may allow identifying patients at high risk for restenosis after stenting.
authors.affiliation: Clemenceau Medical Center, Clemenceau Street, Beirut, Lebanon. elie.chammas@cmc.com.lb
authors.forename: Elie
authors.initials: E
authors.lastname: Chammas
authors.forename: Chadi
authors.initials: C
authors.lastname: Dib
authors.forename: Maya
authors.initials: M
authors.lastname: Rahhal
authors.forename: Toni
authors.initials: T
authors.lastname: Helou
authors.forename: Georges
authors.initials: G
authors.lastname: Ghanem
authors.forename: Walid
authors.initials: W
authors.lastname: Tarcha
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D017023:Coronary Angiography; D003326:Coronary Circulation / Q000502:physiology*; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology* / Q000628:therapy*; D015150:Echocardiography, Doppler / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D015607:Stents; D016896:Treatment Outcome