Objective Patients referred for acute coronary angiography (CAG) with unstable angina (UA) have low mortality and low rate of obstructive coronary artery disease (CAD). Better pre-test selection criteria are warranted. We aimed to assess the current guidelines against other clinical variables as predictors of obstructive CAD in patients with UA referred for acute CAG.
Methods From 2005 to 2012, all CAGs performed at the University Hospital of North Norway, the sole provider of CAG in the region, were recorded in a registry. We included 979 admissions of UA and retrospectively collected data regarding presenting clinical parameters from patient hospital records. Obstructive CAD was defined as ≥50% stenosis and considered prognostically significant if found in the left main stem, proximal LAD or all three main coronary arteries. Characteristics were analysed by logistic regression analysis. A score was developed using ORs from significant factors in a multivariable model.
Results The overall rate of obstructive CAD was 45%, and the rate of prognostically significant CAD was 11%. The risk criteria recommended in American College of Cardiology/American Heart Association and European Society of Cardiology guidelines had an area under the curve (AUC) of 0.58. Adding clinical information increased the AUC to 0.77 (95% CI 0.74 to 0.80). Applying the derived score, we found that 56% (n=546) of patients had a score of <13, which was associated with a negative predictive value of 95% for prognostic significant CAD.
Conclusions The current results suggest that CAG may be postponed or cancelled in more than half of patients with UA by improving pre-test selection criteria with the addition of clinical parameters to current guidelines.
- acute coronary syndrome
- myocardial ischemia
- chest pain
- percutaneous coronary intervention
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Contributors KF collected and analysed the data, interpreted the results and drafted the manuscript. AK interpreted the results and drafted the manuscript. JTM interpreted the results and critically reviewed the manuscript. TT organised the data collection, interpreted the results and critically reviewed the manuscript. HS organised the data collection, collected and analysed the data, interpreted the results and drafted the manuscript.
Funding Research student grant from UiT The Arctic University of Norway, Tromsø.
Competing interests None declared.
Patient consent Not required.
Ethics approval The study was a clinical audit and therefore not subject to evaluation by the Regional Committee of Ethics. It was approved by the Data Protection Official for Research at the University Hospital of North Norway (#0217).
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement No additional data are available.
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