Prognostic Value of Coronary CT Angiography and Calcium Score for Major Adverse Events in Outpatients

Study Questions:

What is the incremental prognostic value of coronary computed tomography angiography (CTA) findings in addition to coronary artery calcium scoring (CACS)?

Methods:

This study examined 5,007 outpatients with CTA and CACS performed at a single center for suspected coronary artery disease (CAD), and evaluated the relationship between CACS severity, CTA stenosis severity, and the plaque composition of the most stenotic lesion by CTA to major adverse cardiac events (MACE). MACE included cardiac death, myocardial infarction (MI), and late revascularization (≥60 days after imaging).

Results:

Mean age was 60 years, 62% were male, and 69% of patients had prior chest pain. Follow-up MACE was available in 4,425 patients (88%), and median follow-up was 3.0 years. MACE occurred in 363 individuals, and included 40 cardiac deaths, 87 MIs, and 236 late revascularization procedures. In comparison to a CACS of 0 as a reference (hazard ratio [HR], 1.0), a CACS of 1-100, 101-400, and >400 was associated with HRs of 7.2, 9.2, and 22.2, respectively (p < 0.001 for each). As compared to the absence of obstructive CAD as a reference (HR, 1.0), one-, two-, and three-vessel obstructive CAD was associated with HRs of 29.0, 40.9, and 75.2, respectively (p < 0.001 for each). Using calcified plaque composition as a reference, noncalcified plaque was associated with an HR of 5.3, and mixed plaque was associated with an HR of 9.5 (p < 0.001 for each). The area under the curve to predict MACE increased from 0.71 for risk factors alone, to 0.82 for risk factors + CACS, to 0.93 for risk factors + CACS + CTA.

Conclusions:

Both CTA and CACS findings are associated with an increased risk of MACE. CTA provides incremental prognostic data to risk factors and CACS alone.

Perspective:

Several multicenter studies have demonstrated that both nonobstructive and obstructive CAD identified by CTA are associated with adverse events, with most studies using all-cause mortality as the primary endpoint. This present single-center study is consistent with these prior studies, although it examines more robust endpoints that include cardiac-specific death, MI, and late revascularization. A limitation of the present study is that approximately two thirds of events represented late revascularization, although in analyses limited to death or MI, both CACS and CTA findings remained associated with these hard adverse events. Interestingly, when the authors examined the composition of the most stenotic lesion, patients with noncalcified or mixed plaque had a significantly increased risk of MACE, as compared to calcified plaque. These findings underscore the potential disadvantage of CACS, as it examines only calcified plaque components, and prompt the need for further research examining the relationship between plaque composition and the risk of cardiac events.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Atherosclerotic Disease (CAD/PAD), Interventions and Coronary Artery Disease, Interventions and Imaging, Angiography, Nuclear Imaging

Keywords: Coronary Artery Disease, Myocardial Infarction, Follow-Up Studies, Plaque, Atherosclerotic, Risk Factors, Constriction, Pathologic, Calcium, Prognosis, Incidence, Death, Outpatients, Coronary Angiography, Lutetium, Chest Pain, Tomography, Coronary Vessels


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