Stress computed tomography perfusion versus stress cardiac magnetic resonance for the management of suspected or known coronary artery disease: resources and outcomes impact (STRATEGY II Study)
Authors: Baggiano A , Guglielmo M , Mushtaq S , Annoni A , Formenti A , Mancini E , Fusini L , Tassetti L , Volpe A , Marchetti F , Cilia F , Maragna R , Junod D , Gaudenzi M , Pontone G 
Published: June 2023

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background
Non-invasive techniques have evolved as "gatekeepers" to invasive coronary angiography (ICA) for symptomatic patients with suspected or known coronary artery disease (CAD). Evaluation of myocardial ischemia with functional tests represents a milestone in CAD detection with proved diagnostic and prognostic power. Coronary computed tomography angiography (CCTA), a non-invasive anatomical assessment, intrinsically lacks physiologic data to categorize the downstream hemodynamic significance of lesions. Stress CT perfusion (stress-CTP) is a recently evolved imaging modality able to assess inducible myocardial perfusion defects. The aim of this study is to compare resources and outcomes Impact of combined CCTA+stress-CTP versus stress cardiovascular magnetic resonance (stress-CMR) in consecutive symptomatic patients with suspected CAD and intermediate to high pre-test likelihood of disease or known CAD or previous history of revascularization.

Methods
624 symptomatic patients with intermediate to high risk pre-test likelihood for CAD or previous history of revascularization referred to our hospital for clinically indicated CCTA+stress-CTP or stress-CMR were enrolled. Stress-CTP scans were performed in 223 patients using 256-row whole heart-coverage scanner, static protocol acquisition and vasodilation induced by adenosine. 401 patients with clinically indicated stress-CMR were evaluated in a 1.5-T scanner after vasodilatation induced with dipyridamole. Patient follow-up was performed at 1 year after index test performance. Endpoints were as follow: 1) all cardiac events as a combined endpoint of revascularization, non-fatal MI and death; 2) hard cardiac events as combined endpoint of non-fatal MI and death.

Results
Stress-CMR group showed lower age, higher prevalence of male gender and higher prevalence of previous revascularization, while CCTA+CTP group showed higher prevalence of family history of CAD and statin use. CCTA was defined positive for obstructive disease in 62% of patients while the addition of CTP on top of CCTA reduced the number of positive patients to 46%. Stress-CMR resulted positive in 23% of subjects. Patients who underwent CCTA+CTP underwent more revascularization (29% versus 7%, p: 0.001) while no differences were found in terms of non-fatal MI and death between the two strategies. According to the predefined endpoints, CCTA+CTP group showed higher rate of all cardiac events (29% vs 8%, p: 0.001) and lower rate of hard cardiac events (0.4% vs 3%, p: 0.033), respectively. Stratifying the baseline characteristics by all cardiac events and hard cardiac events, left ventricle volume and index test strategy predicted all cardiac events while only index test strategy predicted hard cardiac events.

Conclusions
The use of CCTA+CTP strategy was associated with higher referral to revascularization but with a protective trend in terms of hard cardiac events as compared to the usual strategy with lone functional evaluation.