title: Efficacy of contrast medium induced Pd/Pa ratio in predicting functional significance of intermediate coronary artery stenosis assessed by fractional flow reserve: insights from the RINASCI study.
abstract: OBJECTIVE
  The need of adenosine administration for the achievement of maximal hyperaemia limits the widespread application of fractional flow reserve (FFR) in the real world. We hypothesised that Pd/Pa ratio registered during submaximal reactive hyperaemia induced by conventional non-ionic radiographic contrast medium (contrast medium induced Pd/Pa ratio: CMR) can be sufficient for the assessment of physiological severity of stenosis in the vast majority of cases. The aim of the present study was to test the accuracy of CMR in comparison to FFR.
  
  
  RESULTS
  Eighty patients with 104 intermediate coronary stenoses were prospectively and consecutively enrolled. CMR was obtained after intracoronary injection of 6 ml of radiographic contrast medium, while FFR was measured after administration of adenosine. Despite the fact that CMR values were significantly higher than FFR values (0.88 [IR 0.80-0.92] vs. 0.87 [IR 0.83-0.94], p<0.001), a strong correlation between CMR and FFR values was observed (r=0.94, p<0.001) with a close agreement at Bland-Altman analysis (95% CI of disagreement: -0.029 to 0.072). ROC curve analysis showed an excellent accuracy of CMR cut-off of ≤0.83 in predicting FFR value ≤0.80 (AUC 0.97 [95% CI: 0.91-0.99, specificity 96.1, sensitivity 85.7]). Moreover, no FFR value ≤0.80 corresponded to a CMR ≥0.88.
  
  
  CONCLUSIONS
  CMR is accurate in predicting the functional significance of coronary stenosis. This could allow limiting the use of adenosine to obtain FFR to doubtful cases. In particular, we suggest considering a CMR value ≤0.83 to be significant, a CMR value ≥0.88 as not significant, and inducing maximal hyperaemia using adenosine for FFR assessment when CMR is between 0.84 and 0.87.
authors.affiliation: Institute of Cardiology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: Antonio Maria
authors.initials: AM
authors.lastname: Leone
authors.forename: Giancarla
authors.initials: G
authors.lastname: Scalone
authors.forename: Giovanni Luigi
authors.initials: GL
authors.lastname: De Maria
authors.forename: Francesco
authors.initials: F
authors.lastname: Tagliaferro
authors.forename: Andrea
authors.initials: A
authors.lastname: Gardi
authors.forename: Fabio
authors.initials: F
authors.lastname: Clemente
authors.forename: Eloisa
authors.initials: E
authors.lastname: Basile
authors.forename: Pio
authors.initials: P
authors.lastname: Cialdella
authors.forename: Alberto Ranieri
authors.initials: AR
authors.lastname: De Caterina
authors.forename: Italo
authors.initials: I
authors.lastname: Porto
authors.forename: Cristina
authors.initials: C
authors.lastname: Aurigemma
authors.forename: Francesco
authors.initials: F
authors.lastname: Burzotta
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Niccoli
authors.forename: Carlo
authors.initials: C
authors.lastname: Trani
authors.forename: Antonio Giuseppe
authors.initials: AG
authors.lastname: Rebuzzi
authors.forename: Filippo
authors.initials: F
authors.lastname: Crea
mesh_terms: D000241:Adenosine / Q000008:administration & dosage*; D000368:Aged; D019540:Area Under Curve; D006328:Cardiac Catheterization; D003287:Contrast Media / Q000008:administration & dosage*; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D023921:Coronary Stenosis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology; D007269:Injections, Intra-Arterial; D007479:Iopamidol / Q000008:administration & dosage / Q000031:analogs & derivatives*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D014665:Vasodilator Agents / Q000008:administration & dosage*
chemical_list: D003287:Contrast Media; D014665:Vasodilator Agents; C057937:iomeprol; D007479:Iopamidol; D000241:Adenosine