Coronary CT Angiography Given the high accuracy in detecting angiographically signif- icant coronary stenosis, estimates of cardiovascular risk according to the Duke CAD index with data obtained via CCTA appear to be as accurate as those obtained from cardiac catheterization. However, the actual event rates in patients undergoing CCTA have been substantially lower because of differences in the underlying risk profiles of patient groups that have been referred for these 2 procedures.345 Further- more, data from CONFIRM suggest that the finding of nonobstructive CAD on CCTA supplements clinical informa- tion in predicting risk of mortality.286 For example, 20% to 25% of patients with an intermediate pretest likelihood of risk (1% to 3% annual mortality rate) based on clinical informa- tion (without EF) were reassigned to a different risk category according to information from CCTA. Given that failed bypass grafts can result in unprotected CAD, which confers a higher risk, the assessment of the extent of graft patency by CCTA is also of prognostic value.346,347 Although exercise stress testing in general is preferred in risk assessment, for patients unlikely to achieve conclusive results, consensus opinion suggests that it is reasonable to proceed with a CCTA for risk-assessment purposes. Several ongoing trials are comparing the prognostic values of CCTA and functional imaging modalities such as nuclear MPI and stress echocardiography.348 At present, there are no prospectively gathered trial data demonstrating that CCTA leads to better patient selection for medical or invasive intervention or to better clinical outcomes. 3.3. Coronary Angiography 3.3.1. Coronary Angiography as an Initial Testing Strategy to Assess Risk: Recommendations Class I 1. Patients with SIHD who have survived sudden car- diac death or potentially life-threatening ventricular arrhythmia should undergo coronary angiography to assess cardiac risk.349 351 (Level of Evidence: B) 2. 