Coronary artery calcium score as a gatekeeper for further testing in patients with low probability of obstructive coronary artery disease: a cost-effectiveness analysis

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Current guidelines recommend not to routinely test patients with chest pain and low pretest probability (PTP <15%) obstructive coronary artery disease (CAD) but envisage the use risk modifiers such as calcium score (CACS) refine patient selection for testing. The aim this study was assess cost-effectiveness (CE) three different testing strategies in approach symptomatic PTP CAD: A) test; B) perform CACS, withholding if = 0 proceeding CT angiography (CCTA) > 0; C) CCTA all cases, without prior CACS. Methods We developed a CE model using data from two-centre 1385 non-acute <15% who underwent CACS immediately followed by CCTA. Key input included proportion CAD on (10.3%), CACS=0 (57%), negative predictive value (98.9%), which considered gold standard simulation. each strategy defined cost per correct diagnosis. Direct costs were calculated price list Portuguese National Health Service. Indirect costs, including incidental findings, estimated according literature. attributable false-negative set at 3 times false-positive, customary. Results Not would correctly classify 89.7% €121.433 1000 patients, due imputed false negatives. Using gatekeeper diagnose 98.9% €247.116 patients. Employing first-line €271.007 diagnosed Overall, added an additional diagnosis €1.366 CACS±CCTA vs. no testing, €2.172 CACS±CCTA. corresponding thresholds (CET) €943–€3.450 men; €1.527–€1.972 women (Table 1). Conclusions should be disfavoured unless CET is below First-line yields most diagnoses cost-effective above over further between these thresholds, are wider men than women. These findings may inform decisions suitable will ultimately depend amount missed stakeholders willing accept.