title: The ASLA Score: A CT Angiographic Index to Predict Functionally Significant Coronary Stenoses in Lesions with Intermediate Severity-Diagnostic Accuracy.
abstract: OBJECTIVE
  To identify computed tomographic (CT) coronary indexes independently associated with a fractional flow reserve (FFR) of 0.8 or less, to derive a score that combines CT indexes most predictive of an FFR of 0.8 or less, and to evaluate the diagnostic accuracy of the score in predicting an FFR of 0.8 or less.
  
  
  METHODS
  This retrospective study had institutional review board approval and waiver of the need to obtain informed consent. Consecutive patients who underwent CT coronary angiography and FFR assessment with one or more discrete lesion(s) of intermediate (30%-70%) severity at CT were included. Quantitative CT measurements were performed by using dedicated software. The CT indexes evaluated included the following: plaque burden, minimal luminal area and diameter, stenosis diameter, area of stenosis, lesion length, remodeling index, plaque morphology, calcification severity, and the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) score, which approximates the size of the myocardium subtended by a lesion. By using covariates independently associated with an FFR of 0.8 or less, a score was determined on the basis of modified Akaike information criteria, and the C statistics of individual and combined indexes were compared.
  
  
  RESULTS
  Eighty-five patients (mean age, 64.2 years; range, 48-88 years; 65.9% men; 124 lesions; 38 lesions with an FFR ≤ 0.8) were included. Area of stenosis, lesion length, and APPROACH score were the strongest predictors of an FFR of 0.8 or less and were used to derive the ASLA score. The optimism-adjusted Harrell C statistic for the combined score was 0.82, which was superior to that for area of stenosis (0.74), lesion length (0.75), and the APPROACH score (0.71) (P < .001 for trend). The corresponding incremental discrimination improvement indexes were 0.17, 0.11, and 0.19, respectively (P < .001 for all), suggesting that the score improves reclassification compared with any one angiographic index. The average time required for score derivation was 102.6 seconds.
  
  
  CONCLUSIONS
  The ASLA score, which accounts for CT-derived area of stenosis, lesion length, and APPROACH score, may conveniently improve the prediction, beyond individual indexes, of functionally significant intermediate coronary lesions.
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre), Monash University and Monash Heart, Monash Health, 246 Clayton Road, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., S.S., N.N., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); and Discipline of Medicine, Flinders University, Adelaide, Australia (D.P.L.).
authors.forename: Brian S
authors.initials: BS
authors.lastname: Ko
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre), Monash University and Monash Heart, Monash Health, 246 Clayton Road, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., S.S., N.N., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); and Discipline of Medicine, Flinders University, Adelaide, Australia (D.P.L.).
authors.forename: Dennis T L
authors.initials: DT
authors.lastname: Wong
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre), Monash University and Monash Heart, Monash Health, 246 Clayton Road, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., S.S., N.N., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); and Discipline of Medicine, Flinders University, Adelaide, Australia (D.P.L.).
authors.forename: James D
authors.initials: JD
authors.lastname: Cameron
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre), Monash University and Monash Heart, Monash Health, 246 Clayton Road, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., S.S., N.N., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); and Discipline of Medicine, Flinders University, Adelaide, Australia (D.P.L.).
authors.forename: Darryl P
authors.initials: DP
authors.lastname: Leong
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre), Monash University and Monash Heart, Monash Health, 246 Clayton Road, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., S.S., N.N., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); and Discipline of Medicine, Flinders University, Adelaide, Australia (D.P.L.).
authors.forename: Siang
authors.initials: S
authors.lastname: Soh
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre), Monash University and Monash Heart, Monash Health, 246 Clayton Road, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., S.S., N.N., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); and Discipline of Medicine, Flinders University, Adelaide, Australia (D.P.L.).
authors.forename: Nitesh
authors.initials: N
authors.lastname: Nerlekar
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre), Monash University and Monash Heart, Monash Health, 246 Clayton Road, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., S.S., N.N., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); and Discipline of Medicine, Flinders University, Adelaide, Australia (D.P.L.).
authors.forename: Ian T
authors.initials: IT
authors.lastname: Meredith
authors.affiliation: From the Monash Cardiovascular Research Centre, Department of Medicine (Monash Medical Centre), Monash University and Monash Heart, Monash Health, 246 Clayton Road, Clayton, 3168 VIC, Australia (B.S.K., D.T.L.W., J.D.C., S.S., N.N., I.T.M., S.K.S.); Discipline of Medicine, University of Adelaide, Adelaide, Australia (D.T.L.W., D.P.L.); and Discipline of Medicine, Flinders University, Adelaide, Australia (D.P.L.).
authors.forename: Sujith K
authors.initials: SK
authors.lastname: Seneviratne
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017023:Coronary Angiography / Q000379:methods*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed