P2241Patients examined with coronary computed tomography angiography have comparable five-year outcomes to age- and sex-matched population controls
Authors: Kragholm K , Tayal B , Sejersen H M , Zaremba T , Noergaard B L , Boetker H E , Koeber L , Torp-Pedersen C T , Soegaard P , Freeman P 
Published: October 2019

Abstract

Background
According to Danish national guidelines, coronary computed tomography angiography (CCTA) is the preferred frontline test in patients without known coronary artery disease (CAD) and stable symptoms indicative of CAD. Over the last decade in Denmark, we have seen a steadily and considerable increase in CCTA use. Data on long-term cardiovascular risk following CCTA remains limited, in particular in comparison to background population controls.

Purpose
To study individual and composite five-year outcomes of mortality, myocardial infarction (MI) and revascularization in CCTA-examined patients compared to background population controls.

Methods
Nationwide registry-based study including 58,176 patients with an incident CCTA examination during 2007–2014 in Denmark versus 116,352 age- and sex-matched population controls. Despite no detailed information on CCTA results were available, a landmark analysis including patients and corresponding controls alive six months post-CCTA enabled us to study five patient categories: 1) 19,135 patients with no relevant medical therapy (nitrates, cholesterol-lowering, antiplatelet and/or anticoagulant drugs) before or 180 days post-CCTA; 2) 6,073 patients on relevant medical therapy prior to but not 180 days post-CCTA; 3) 5,086 patients who initiated relevant medical therapy during 180 days post-CCTA; 4) 19,809 patients on relevant medical therapy both before and during 180 days post-CCTA; and 5) 8,073 patients with myocardial infarction (MI) or treated with percutaneous intervention (PCI) or coronary artery bypass surgery (CABG) within 180 days post-CCTA. Within each CCTA patient group, two controls matched on age and sex were identified for each CCTA patient. Neither CCTA-patients nor controls had prior ischemic heart disease.

Results
Outcomes of MI for CCTA patient groups 1)-5) versus controls were: 0.3%, 0.6%, 0.8%, 0.7%, and 11.4% versus 0.7%, 1.1%, 1.0%, 1.1%, and 1.5%. Corresponding figures for all-cause mortality were: 2.2%, 2.0%, 4.1%, 4.9%, and 6.8%, versus 2.1%, 2.8%, 4.2%, 4.3%, and 6.4%. For composite endpoint of MI, PCI or CABG, results for CCTA patients versus controls were: 0.3%, 0.6%, 0.8%, 0.7%, and 18.2% versus 0.9%, 1.3%, 1.2%, 1.4%, and 1.9%. Lastly, for composite endpoint of MI, PCI, CABG or death, results for CCTA patients versus controls were: 2.5%, 2.6%, 4.8%, 4.9%, and 24.2% versus 3.0%, 3.9%, 5.3%, 6.1%, and 8.0%.

Conclusions
Only the CCTA group treated with PCI or CABG or diagnosed with MI during the first 180 days post-CCTA had substantially higher five-year MI event rates and composite endpoints of MI, PCI or CABG and MI, PCI, CABG or death. In addition, no difference in five-year all-cause mortality was seen for all CCTA patient groups when compared to their respective controls. Altogether, the majority of CCTA-examined patients were event-free at five-year follow-up suggesting a potential overutilization of CCTA and a need for refinement of CCTA referral criteria.