title: Diagnostic role of coronary calcium scoring in the rapid access chest pain clinic: prospective evaluation of NICE guidance.
abstract: BACKGROUND
  Coronary artery calcium (CAC) imaging by unenhanced computed X-ray tomography (CT) is recommended as an initial diagnostic test for patients with stable chest pain symptoms but a low likelihood (10-29%) of underlying obstructive coronary artery disease (CAD) after clinical assessment. The recommendation has not previously been tested prospectively in a rapid access chest pain clinic (RACPC).
  
  
  METHODS
  We recruited 300 consecutive patients presenting with stable chest pain to the RACPC of three hospitals. All patients underwent CAC imaging, followed by invasive coronary angiography (ICA) in patients with CAC ≥ 1000 Agatston units (Au) and CT coronary angiography (CTCA) in those with CAC <1000. Patients with 50-70% stenosis on CTCA underwent myocardial perfusion scintigraphy (MPS) while those with ≥ 70% stenosis underwent ICA. Obstructive CAD was defined as ≥ 70% stenosis on ICA or the presence of inducible ischaemia on MPS. Patients were followed up clinically for a mean of 17 (SD 6) months.
  
  
  RESULTS
  The mean patient age was 60.6 (SD 9.6) years and 48% were males. Obstructive CAD was found in 56 (19%) patients, of whom 42 (14%) underwent revascularization. CAC was zero in 131 (44%) patients, of whom two (1.5%) had obstructive CAD and one (0.8%) underwent revascularization. The sensitivity, specificity, negative predictive value, and positive predictive value of CAC ≥ 1 for detection of obstructive CAD were 96, 53, 32, and 98%, respectively. None of the 57 patients with low pre-test probability of CAD and zero CAC had obstructive CAD or suffered a cardiovascular event during the follow-up.
  
  
  CONCLUSIONS
  Patients with stable chest pain symptoms but a low likelihood of CAD can safely be diagnosed as not having obstructive CAD in the absence of detectable coronary calcification by unenhanced CT. Patients with CAC >400 Au have a high prevalence of obstructive CAD and further investigation with ICA or functional imaging may be warranted rather than CTCA. These findings support NICE guidance for the investigation of stable chest pain. ClinicalTrials gov identifier: NCT01464203.
authors: Clinical Imaging and Research Centre, Wellington Hospital, London, UK.
authors: Ajay
authors: A
authors: Yerramasu
authors: Clinical Imaging and Research Centre, Wellington Hospital, London, UK University of Middlesex, London, UK.
authors: Avijit
authors: A
authors: Lahiri
authors: Clinical Imaging and Research Centre, Wellington Hospital, London, UK.
authors: Shreenidhi
authors: S
authors: Venuraju
authors: Clinical Imaging and Research Centre, Wellington Hospital, London, UK.
authors: Alain
authors: A
authors: Dumo
authors: Clinical Imaging and Research Centre, Wellington Hospital, London, UK.
authors: David
authors: D
authors: Lipkin
authors: National Heart and Lung Institute, Imperial College London, London, UK Royal Brompton Hospital, Sydney St, London SW3 6NP, UK srunderwood@imperial.ac.uk.
authors: S Richard
authors: SR
authors: Underwood
authors: Royal Free London Foundation Trust, London, UK.
authors: Roby D
authors: RD
authors: Rakhit
authors: Barnet and Chase Farm Hospitals NHS Trust, London, UK.
authors: Deven J
authors: DJ
authors: Patel
mesh_terms: D000465:Algorithms; D002114:Calcinosis / Q000000981:diagnostic imaging*; D002637:Chest Pain / Q000000981:diagnostic imaging*; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007479:Iopamidol / Q000031:analogs & derivatives; D008131:London; D008297:Male; D008875:Middle Aged; D018710:Pain Clinics; D017410:Practice Guidelines as Topic; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol
keywords: CAD diagnosis; CT coronary angiography; Coronary calcium; Myocardial perfusion scintigraphy; NICE chest pain guidance