title: Correlations between fractional flow reserve and intravascular ultrasound in patients with an ambiguous left main coronary artery stenosis.
abstract: BACKGROUND
  Intravascular ultrasound (IVUS) is being used to assess the significance of a left main coronary artery stenosis (LMCS). However, the cutoff values of IVUS parameters at which to predict a fractional flow reserve (FFR) of 0.75 are unknown.
  
  
  RESULTS
  In 55 patients with an angiographically ambiguous LMCS, a pressure guidewire was used to calculate FFR, and IVUS parameters were calculated after automatic pullback. FFR averaged 0.86+/-0.13 (range, 0.55 to 1.0). IVUS minimum lumen diameter (MLD), minimum lumen area (MLA), cross-sectional narrowing (CSN), and area stenosis (AS) were 3.8+/-0.61 mm, 7.65+/-2.9 mm2, 59+/-13%, and 47+/-19%, respectively. Regression analysis demonstrated strong correlations between FFR and MLD (r=0.79, P<0.0001) as well as between FFR and MLA (r=0.74, P<0.0001). There were inverse, moderate correlations between FFR and CSN (r=0.69, P<0.0001), followed by those between FFR and AS (r=0.54, P<0.0001). Compared with FFR as the "gold standard," an MLD of 2.8 mm had the highest sensitivity and specificity (93% and 98%, respectively) for determining the significance of an LMCS, followed by an MLA of 5.9 mm2 (93% and 95%, respectively). Based on an FFR <0.75 and an FFR > or =0.75, the 38-month survival and event-free survival estimates (EFSEs) were both 100% and 100% versus 90%, respectively (P=NS).
  
  
  CONCLUSIONS
  We conclude that (1) an IVUS MLD and MLA of 2.8 mm and 5.9 mm2, respectively, strongly predict the physiological significance of an LMCS and (2) among patients with an LMCS, an FFR of 0.75 is a strong predictor of survival and EFSE.
authors.affiliation: Division of Cardiology, University of Louisville, Louisville, KY 40292, USA.
authors.forename: Venu
authors.initials: V
authors.lastname: Jasti
authors.forename: Eugen
authors.initials: E
authors.lastname: Ivan
authors.forename: Venkata
authors.initials: V
authors.lastname: Yalamanchili
authors.forename: Nattawut
authors.initials: N
authors.lastname: Wongpraparut
authors.forename: Massoud A
authors.initials: MA
authors.lastname: Leesar
mesh_terms: D000241:Adenosine; D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000706:statistics & numerical data; D006328:Cardiac Catheterization; D002318:Cardiovascular Diseases / Q000401:mortality; D017023:Coronary Angiography; D001026:Coronary Artery Bypass / Q000706:statistics & numerical data; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006439:Hemodynamics; D006801:Humans; D006940:Hyperemia / Q000139:chemically induced / Q000503:physiopathology; D015993:Life Tables; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology; D011312:Pressure; D016037:Single-Blind Method; D014160:Transducers, Pressure; D018084:Ultrasonography, Interventional
chemical_list: D000241:Adenosine