title: CT coronary angiography in low- to intermediate-risk patients: less radiation, less invasive angiography, and less revascularisation.
abstract: OBJECTIVE
  We investigated whether any change in the use of invasive coronary angiography and coronary revascularisation after CT coronary angiography in patients with a low to intermediate pre-test probability of coronary artery disease could be explained from alterations in patient characteristics.
  
  
  METHODS
  A cohort study based on data samples from the Western Denmark Heart Registry. Follow-up ended on 11 March 2014.
  
  
  RESULTS
  A total of 3541 persons were examined during the period of January 2010-December 2013. The median radiation dose was reduced from 4.2 to 2.2 mSv (p < 0.001) due to improved technology. The immediate referral rate for subsequent myocardial perfusion scans was increased from 2.8% to 10.0% (p < 0.001), while the immediate referral rate for invasive coronary angiography decreased from 25.3% to 10.8% (p < 0.001). The revascularisation rate diminished from 10.4% to 6.3%. The multivariable adjusted hazard ratio (95% confidence interval) for invasive coronary angiography during follow-up after CT coronary angiography was 0.59 (0.47-0.74) and that for coronary revascularisation was 0.66 (0.45-0.97) in 2013 compared to that in 2010.
  
  
  CONCLUSIONS
  The radiation dose diminished considerably. The reductions in the use of invasive coronary angiography and coronary revascularisation could not be explained by changes in patient characteristics but are driven by an increased use of perfusion scans in combination with increasing use of measurement of functional coronary flow reserve.
authors.affiliation: Diagnostic Centre, University Research Clinic for Innovative Patient Pathways, Silkeborg Regional Hospital , Silkeborg , Denmark.
authors.forename: Kirsten Schou
authors.initials: KS
authors.lastname: Nørgaard
authors.forename: Christin
authors.initials: C
authors.lastname: Isaksen
authors.forename: Jørgen Selmer
authors.initials: JS
authors.lastname: Buhl
authors.forename: Agnete Hedemann
authors.initials: AH
authors.lastname: Nielsen
authors.forename: Aage
authors.initials: A
authors.lastname: Nørgaard
authors.forename: Grazina
authors.initials: G
authors.lastname: Urbonaviciene
authors.forename: Lars
authors.initials: L
authors.lastname: Frost
mesh_terms: D000328:Adult; D000368:Aged; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000601:surgery; D023921:Coronary Stenosis / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009204:Myocardial Revascularization; D016016:Proportional Hazards Models; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed
keywords: angiography; diagnosis; ischaemic heart disease