Introduction
Accurate assessment of patients with chest pain without electrocardiographic changes or elevation of serum cardiac enzymes is challenging. There is increased interest in the role of dobutamine stress echocardiography (DSE) and adenosine magnetic resonance imaging (AMRI) performed in the chest pain unit as a diagnostic method to rule out Coronary Artery Disease (CAD) as the cause of the chest pain in this population.
Purpose
The purpose of this study was to compare DSE and AMRI in patients with low probability of CAD.
Methods
Inclusion criteria for the study were patients with normal EKG (no signs of cardiac ischemia) and negative cardiac enzymes, who were admitted to the Cardiac Decision Unit (CDU) from 2006–2008 at Emory University Hospital. The diagnostic method used was chosen randomly by physician preference. T-test was used to assess differences in continuous variables, and X2 square to test differences in categorical variables between the two groups. Logistic regression was used to assess the likelihood of detecting CAD after adjusting for technique used and baseline characteristics.
Results
A total of 306 patients were included, 103 patients were evaluated with AMRI and 203 underwent DSE. Mean age was similar among groups (52 for AMRI vs. 54 for DSE). Patients in AMRI group were more likely to be males, had more risk factors for CAD, and used more Beta blockers or aspirin at baseline compared to patients evaluated by DSE. AMRI identified more patients as having CAD compared to DSE (13 (12.6%) vs.3 (1.5%), p = < 0.0001). This difference remained significant even after adjusting for baseline characteristics and risk factors [OR of CAD by AMRI vs DSE = 7.01, CI (1.48–33.16) p = 0.014]. (Data in Table 1.)
Table 1
| Characteristics | MRI | DSE | p-value |
|---|---|---|---|
| AGE | 52 ± 12 | 54 ± 13 | 0.0571 |
| Gender (males) | 144 (70.9%) | 38 (38%) | <0.0001 |
| CAD | 16 (16%) | 13 (6.4%) | 0.0076 |
| HTN | 66 (64.7%) | 111 (54.7%) | 0.0941 |
| DM | 30 (29.7%) | 36 (17.7%) | 0.0171 |
| SMOKING | 20 (19.6%) | 39 (19.5%) | 0.2967 |
| Dyslipidemia | 40 (39.2%) | 46 (22.8%) | 0.0027 |
| Family_history_of_CAD | 52 (51%) | 74 (54.4%) | 0.6029 |
| EF | 65.0 ± 10.4 | 64.2 ± 6.1 | 0.4235 |
| Coronoary Artery Disease | 13 (12.6%) | 3 (1.5%) | <0.0001 |
| Beta Blocker use | 29 (28.4%) | 25 (12.4%) | 0.0005 |
| Ca_B | 19 (18.6%) | 27 (13.4%) | 0.2268 |
| ACEi | 21 (20.6%) | 21 (10.4%) | 0.015 |
| ARBs | 14 (13.7%) | 20 (9.9%) | 0.3178 |
| ASA | 27 (26.5%) | 21 (10.4%) | 0.0003 |
Conclusion
In this prospective study of patients with low probability of CAD, AMRI identified more cases of CAD than DSE even after adjusting for baseline characteristics. Although selection bias could account for part of these results, a higher sensitivity for AMRI is suggested.