Prognostic Value of CT Angiography for Major Adverse Cardiac Events in Patients With Acute Chest Pain From the Emergency Department: 2-Year Outcomes of the ROMICAT Trial
What is the prognostic significance of detection of coronary artery disease (CAD) and regional wall motion abnormalities (RWMAs) on computed tomographic angiography (CTA) in patients presenting to an emergency department with chest pain?
Patients presenting with acute chest pain, a nonischemic electrocardiogram, and normal initial troponin were enrolled in the ROMICAT (Rule Out Myocardial Infarction Using Computer Assisted Tomography) trial. Patients underwent contrast-enhanced 64-slice CT, the results of which remained blinded to patients and care givers. Multidetector CTs were analyzed for presence of plaque, stenosis >50%, and left ventricular RWMAs. Major adverse cardiac events (MACE) were defined as cardiac death, nonfatal myocardial infarction, or coronary revascularization. Patients were followed for 2 years.
A total of 183 patients had no CAD, 117 had nonobstructive CAD, and 68 had obstructive CAD. Patients with obstructive CAD were older and were likely to have diabetes, hypertension, and other traditional risk factors. Of the initial 368 patients, complete follow-up was available in 333 patients. Twenty-five patients experienced a total of 35 MACE. There were no cardiac deaths, 12 myocardial infarctions, and 23 revascularizations. There was a progressive increase in 2-year probability of MACE across the CT strata of coronary disease, from 0% to 3% to 30.3% when comparing no CAD, nonobstructive CAD, and obstructive CAD (0.0001%). A similar increase across the strata was noted for the combined CAD and RWMA variables. Patients with no stenosis or WMA had a 2-year event rate of 0.9%, and an event rate of 62.4% for patients with CAD and RWMA (p < 0.0001). C-statistics for predicting MACE progressively increased from 0.61 to 0.84 and to 0.91 when comparing clinical assessment with CAD data and subsequent additional RWMA data (both comparisons p < 0.0001). The majority of MACE occurred during the first 30 days after CTA; however, CTA results remained predictive of MACE at the 1- and 2-year time points as well.
Assessment of coronary disease and WMA using CTA provides prognostic information for up to 2 years after presentation. Complete absence of CAD on CTA provided a 2-year MACE-free survival.
Multidetector CTA has been well established as an accurate means for identifying the presence and location of epicardial CAD, and in previous studies, has provided an exceptionally high (100% in many instances) negative predictive value for predicting short-term events. This study is unique in that the CTAs were performed in relatively low-risk patients presenting to the emergency department with acute chest pain, after which results were blinded to treating physicians and the patient. It also provides a 2-year follow-up with respect to subsequent events. It evaluated regional wall motion as well as the presence and absence of CAD. The highest likelihood of events occurred in patients with both CAD and RWMAs. In this study, the majority of MACE occurred within the first 30 days. However, results of CTA remained predictive of events at 1 and 2 years as well. As with previous studies, the greatest strength of these observations is in the zero event rate in patients with normal CTA, which allows identification of a subset of patients who remain event-free for at least 2 years following the study.
Keywords: Coronary Artery Disease, Myocardial Infarction, Follow-Up Studies, Tomography, X-Ray Computed, Emergency Service, Hospital, Electrocardiography, Hypertension, Diabetes Mellitus, Troponin
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