title: Correlation between optical coherence tomography-derived intraluminal parameters and fractional flow reserve measurements in intermediate grade coronary lesions: a comparison between diabetic and non-diabetic patients.
abstract: BACKGROUND
  Fractional flow reserve (FFR) measurements accurately assess functional relevance in intermediate grade coronary lesions. A significant relationship between hemodynamic stenosis severity and optical coherence tomography (OCT)-derived intraluminal dimensions has recently been demonstrated. However, morphologic thresholds to identify significant stenoses are variable and exploration of this correlation in patients with diabetes mellitus (DM) remains currently incomplete. This study aimed at comparing the diagnostic value of intraluminal parameters as determined by OCT to predict FFR ≤0.8 in lesions of patients with versus without DM.
  
  
  METHODS
  In 100 patients (DM = 56, non-DM = 44) with 142 coronary de novo lesions (DM = 80, non-DM = 62) of intermediate grade as determined by quantitative coronary angiography, we performed OCT and FFR. Stenoses were defined functionally relevant if FFR was ≤0.8.
  
  
  RESULTS
  FFR measurements in the overall study cohort, the DM and the non-DM group correlated significantly with minimal lumen area (MLA) [overall: r (2) = 0.339, DM: r (2) = 0.341, non-DM: r (2) = 0.355 (all p < 0.001)], percent area stenosis [overall: r (2) = 0.352, DM: r (2) = 0.376, non-DM: r (2) = 0.351 (all p < 0.001)] and minimal lumen diameter [overall: r (2) = 0.333, DM: r (2) = 0.277, non-DM: r (2) = 0.417 (all p < 0.001)] without differing statistically between diabetic and non-diabetic patients (p = ns). Receiver operating characteristic analysis demonstrated that among OCT-derived parameters, MLA predicted FFR ≤0.8 with the best diagnostic efficiency and with similar cut-off values for all patients [area under the curve (AUC) = 0.836, 95% confidence interval (CI) = 0.772-0.901, cut-off value = 1.64 mm(2)] as well as for diabetic (AUC = 0.840, 95% CI = 0.754-0.927, cut-off value = 1.59 mm(2)) and non-diabetic subjects (AUC = 0.833, 95% CI = 0.734-0.932, cut-off value = 1.64 mm(2)).
  
  
  CONCLUSIONS
  In both, diabetic and non-diabetic patients, FFR and OCT-derived intraluminal measurements are significantly correlated and OCT predicts hemodynamically relevant coronary stenosis with moderate diagnostic efficiency.
authors.affiliation: Department of Cardiology, Medical Clinic I, University Hospital of the RWTH Aachen, Pauwelsstr. 30, 52074, Aachen, Germany, sreith@ukaachen.de.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Reith
authors.forename: Simone
authors.initials: S
authors.lastname: Battermann
authors.forename: Martin
authors.initials: M
authors.lastname: Hellmich
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Marx
authors.forename: Mathias
authors.initials: M
authors.lastname: Burgmaier
mesh_terms: D000368:Aged; D019540:Area Under Curve; D006328:Cardiac Catheterization; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D023921:Coronary Stenosis / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D003331:Coronary Vessels / Q000473:pathology* / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D003925:Diabetic Angiopathies / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012372:ROC Curve; D012307:Risk Factors; D012720:Severity of Illness Index; D041623:Tomography, Optical Coherence