Risk Stratification by Cardiac Computed Tomographic Angiography

The importance of risk stratification in the management of symptomatic patients with known or suspected coronary artery disease is well recognized. Risk stratification not only informs the clinician's response to queries regarding prognosis but also helps the clinician choose appropriate therapy.1 Cardiac computed tomographic angiography (CCTA) is a relatively new tool for this purpose. Single-center studies have suggested its potential utility in estimating the prognosis of patients with known or suspected coronary artery disease (CAD).2 In this issue of Circulation: Cardiovascular Imaging , Chow et al3 report the findings of a large international multi-center registry (CONFIRM) that examines the value of CCTA for risk stratification. The strengths of the study include its large size (27 125 patients), its multicenter nature (12 participating centers in 6 different countries), its prospective nature, and the use of all-cause mortality as an end point. Although the authors describe their use of all-cause mortality as a potential limitation, Lauer et al have argued that this end point is actually preferred.4Article see p 463To their credit, Chow et al performed a stepwise analysis incorporating first clinical variables, then clinical variables and the left ventricular ejection fraction (LVEF) by CCTA, and then clinical variables, LVEF, and CAD severity assessed by CCTA. The authors also calculated the net reclassification improvement. This approach tries to quantify the prevalence of clinically meaningful change in individual patients. Past studies considered this concept,5,6 but statistical rigor has recently been added.7 The authors conclude that CCTA measures of LVEF and CAD severity are incremental to clinical variables in predicting all-cause mortality. These results add significantly to the evidence base for CCTA. The remainder of this editorial will consider the implications of these data for the evidence-based clinician evaluating a symptomatic patient with suspected …