title: Frame count reserve.
abstract: BACKGROUND
  The Doppler wire-derived (relative) coronary flow velocity reserve (CVR) that is used to evaluate functional significance of a coronary stenosis is a method performed only by interventional cardiologists. An angiographic method would be useful in the diagnostic catheterization laboratory. For this purpose, we investigated the relation between TIMI frame count reserve (FCR) and CVR.
  
  
  RESULTS
  In 38 patients, (relative) FCR of left anterior descending (LAD) and left circumflex coronary artery (LCx) was calculated by using manual, synchronized contrast agent injections and compared with (relative) CVR. In addition, vessel length was measured with an intracoronary guidewire and frame count flow velocity was calculated and compared with average peak velocity. There was a strong correlation between FCR and CVR (r=0.62, P<0.001) and between relative FCR and relative CVR (r=0.84, P<0.001). The LAD was significantly longer than the LCx (mean, 14.3+/-1.6 cm versus 11.4+/-1.8 cm, P<0.001), and, therefore, TIMI frame count of LAD was significantly higher than of LCx (mean basal 32.5+/-15.1 versus 23.6+/-9.1 and hyperemic 12.1+/-6.6 versus 8.7+/-3.2, both P<0.02). However, all flow velocity measurements and estimations of volume flow were not different for LAD compared with LCx. There were also no differences between mean FCR and CVR of LAD or LCx, of both vessels compared with each other and between mean relative FCR and relative CVR.
  
  
  CONCLUSIONS
  The (relative) frame count reserve can be used to estimate (relative) coronary flow velocity reserve.
authors.affiliation: Hospital of the Free University, Department of Cardiology, Amsterdam, The Netherlands. mg.stoel@vumc.nl
authors.forename: Martin G
authors.initials: MG
authors.lastname: Stoel
authors.forename: Felix
authors.initials: F
authors.lastname: Zijlstra
authors.forename: Cees A
authors.initials: CA
authors.lastname: Visser
mesh_terms: D000241:Adenosine; D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000175:diagnosis* / Q000503:physiopathology; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D003326:Coronary Circulation; D023921:Coronary Stenosis / Q000175:diagnosis* / Q000503:physiopathology; D003331:Coronary Vessels / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D018084:Ultrasonography, Interventional; D014654:Vascular Patency / Q000187:drug effects; D014665:Vasodilator Agents
chemical_list: D003287:Contrast Media; D014665:Vasodilator Agents; D000241:Adenosine