title: Relationship between reversibility score on corresponding left ventricular segments and fractional flow reserve in coronary artery disease.
abstract: OBJECTIVE
  The objective of this study was to find the correlation between the severity of perfusion abnormality detected by scintigraphy and the FFR value, as well as the localization of a particular coronary lesion. On the basis of FFR values and the corresponding left ventricular segments, we proposed a combined index to aim for better correlation with myocardial ischemia than the FFR parameter alone.
  
  
  METHODS
  Twenty-eight patients (male: 22, female: 6, age 62±7.62) having FFR measurements and myocardial perfusion SPECT studies were enrolled in our retrospective analysis. FFR measurements on 36 vessels (20 LAD, 6 LCx, 10 RCA) with intermediate stenosis (40%-60%) were compared to the Tc-99m SestaMIBI myocardial perfusion SPECT studies. SPECT studies were performed before the invasive procedure in all cases. We introduced a new ischemic index, the left ventricular ischemic index (LVIi), by combining FFR values with the number of corresponding myocardial segments (N) [LVIi=N x (1-FFR)]. This index correlated with the regional myocardial perfusion defects identified on the scintigrams. A perfusion reversibility score of 2 or above was considered indicative of active ischemia (regional difference score: rDSc). For the statistical analysis, we used linear regression analysis and receiver operating characteristic (ROC) curve analysis to compare the different parameters.
  
  
  RESULTS
  A close linear relationship was found between the LVIi and rDSc values (p<0.001) with linear regression analysis. When analyzing all FFR values independently of the localization of the lesions, they also correlated significantly to the rDSc, but this relation was not as close. LVIi predicted active ischemia (≥2 rDSc) on myocardial scintigraphy with 78% sensitivity and 94% specificity when the cutoff value was set to 0.96. FFR alone predicted ischemia on scintigraphy with 72% sensitivity and 94% specificity at the best 0.8 cut-off value. The area under the ROC curve was significantly higher for LVIi than FFR (0.94 vs. 0.87; p<0.05).
  
  
  CONCLUSIONS
  The scintigraphic data indicate that an LVIi >0.96 implies a clinically relevant stenotic lesion. In our opinion, FFR values, weighted with the corresponding left ventricular segments, should be taken into consideration for the best clinical decision-making.
authors.affiliation: Institute of Cardiology, University of Debrecen Clinical Center; Debrecen-Hungary. kracskobertalan@gmail.com.
authors.forename: Bertalan
authors.initials: B
authors.lastname: Kracskó
authors.forename: Ildikó
authors.initials: I
authors.lastname: Garai
authors.forename: Sándor
authors.initials: S
authors.lastname: Barna
authors.forename: Gábor Tamás
authors.initials: GT
authors.lastname: Szabó
authors.forename: Ildikó
authors.initials: I
authors.lastname: Rácz
authors.forename: Rudolf
authors.initials: R
authors.lastname: Kolozsvári
authors.forename: Balázs
authors.initials: B
authors.lastname: Tar
authors.forename: Csaba
authors.initials: C
authors.lastname: Jenei
authors.forename: József
authors.initials: J
authors.lastname: Varga
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Kõszegi
mesh_terms: D001783:Blood Flow Velocity; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003326:Coronary Circulation; D005260:Female; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D017256:Technetium Tc 99m Sestamibi
chemical_list: D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi