title: Cardiac allograft vasculopathy after heart transplantation: electrocardiographically gated cardiac CT angiography for assessment.
abstract: OBJECTIVE
  To evaluate the diagnostic accuracy of cardiac computed tomographic (CT) angiography without the use of β-blockers compared with that of invasive angiography for the detection of cardiac allograft vasculopathy (CAV) in heart transplant recipients.
  
  
  METHODS
  The study was approved by the research ethics committee and informed consent was obtained. Heart transplant recipients (n = 138) scheduled for routine invasive angiography were prospectively enrolled to undergo CT to evaluate coronary artery calcification and retrospectively gated cardiac CT angiography with a 64-section scanner. The cardiac CT angiographic images were systematically analyzed for image quality. Degree of CAV was assessed by using a 15-coronary segments model. The area under the receiver operating characteristic curve, sensitivity, specificity, and negative and positive predictive values of cardiac CT angiography for detection of CAV with any degree of stenosis and greater than or equal to 50% stenosis were calculated.
  
  
  RESULTS
  Coronary artery calcification was absent in 82 patients, five (6%) of whom had CAV with 50% or more stenosis. Interpretable image quality was obtained in 130 (96%) of the 136 patients who completed the study and 1900 (98%) of 1948 segments. At the patient level, cardiac CT angiography had an area under the receiver operating characteristic curve, sensitivity, specificity, and positive and negative predictive values of 0.880 (95% confidence interval: 0.819, 0.941), 98%, 78%, 77%, and 98%, respectively, for diagnosis of CAV with any degree of stenosis, but for CAV with 50% or more stenosis, the corresponding values were 0.942 (95% confidence interval: 0.885, 1.000), 96%, 93%, 72%, and 99%, respectively. None of the 61 patients with normal cardiac CT angiographic results had CAV on the basis of invasive angiographic images.
  
  
  CONCLUSIONS
  The study results show that cardiac CT angiography compares favorably with invasive angiography in detecting CAV in heart transplant recipients and may be a preferable screening technique because of its noninvasive nature. The absence of coronary artery calcification alone is not reliable enough for excluding CAV.
authors: Department of Imaging, Harefield Hospital, Royal Brompton & Harefield NHS Foundation Trust, Hill End Rd, Middlesex UB9 6JH, England. t.mittal@rbht.nhs.uk
authors: Tarun K
authors: TK
authors: Mittal
authors: Mathen G
authors: MG
authors: Panicker
authors: Andrew G
authors: AG
authors: Mitchell
authors: Nicholas R
authors: NR
authors: Banner
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D055424:Cardiac-Gated Imaging Techniques; D016009:Chi-Square Distribution; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D016027:Heart Transplantation / Q000000981:diagnostic imaging*; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D011857:Radiographic Image Interpretation, Computer-Assisted; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide