Computed tomography to replace invasive coronary angiography? The DISCHARGE trial

Ongoing advancements of coronary computed tomographic angiography (CTA) continue to challenge the role of invasive coronary angiography (ICA) as the gold standard for the evaluation of coronary artery disease (CAD). To investigate the comparative effectiveness of ICA when compared with CTA as an initial diagnostic imaging strategy the DISCHARGE Trial enrolled 3561 patients with stable chest pain and an intermediate pre-test probability of obstructive CAD. The study showed no difference between CTA and ICA in the incidence of the primary composite outcome of cardiovascular death, non-fatal myocardial infarction, or non-fatal stroke during 3.5 years of follow up. As with many trials that advance a field, this trial raises several additional questions of interest that will be discussed. Furthermore, recent studies focused on the discrepancies of CTA vs. ICA indicate that the status of CTA remains unchanged in its ability to rule out disease but at present cannot be considered a substitute for ICA when coronary lesions are documented. Thus, a change in clinical practice patterns likely requires evidence from clinical studies demonstrating equivalence of CT to ICA for guiding medical management. Developments, however, are swift, and CT technology is catching up on its invasive counterpart.