Dobutamine stress cardiac magnetic resonance versus echocardiography for the assessment of outcome in patients with suspected or known coronary artery disease. Are the two imaging modalities comparable?

PURPOSE To compare the value of Dobutamine stress echocardiography (DSE) with that provided by Dobutamine Cardiac Magnetic Resonance (DCMR) for the non-invasive risk stratification of patients with suspected or known coronary artery disease (CAD). METHODS Patients with suspected or known CAD underwent either DSE or DCMR using the same standardized protocol. Patient matching was then performed retrospectively for age, gender and risk factors. Outcome data including cardiac death and non-fatal myocardial infarction (defined as hard cardiac events) and 'late' revascularization performed >90days after the diagnostic procedures were collected during at least 6months. RESULTS Follow-up data were available in 1852 patients who completed either DSE (n=884) or DCMR (n=884) during a mean follow-up duration of 4.1±2.4 and 3.9±1.9years, respectively (p=NS). Matched patients exhibited an overall high risk profile (69±9years; 69% male, 70% history of CAD and 26% diabetes mellitus in both groups). Using multivariable analysis, both modalities successfully identified patients with inducible ischemia at higher risk for subsequent hard cardiac events, surpassing the value of conventional risk factors like age, male gender and diabetes (HR=9.2; 95%CI=5.6-14.9 for DCMR versus 2.5; 95%CI=1.7-3.7 for DSE). By testing for interaction the predictive capacity of DCMR was higher than that provided by DSE (p=0.02). Patients with negative DCMR exhibited lower event rates compared to those with negative DSE (annual hard cardiac event rate of 0.8% versus 3.2%, p=0.002). CONCLUSIONS DSE & DCMR aid the risk stratification of CAD patients. However, inducible WMA during DCMR are associated with a higher risk for subsequent cardiac events. Patients with negative DCMR on the other hand, exhibited a lower event rate compared to those with negative DSE.