Fifty percent of patients with acute chest pain and low-to-intermediate likelihood of acute coronary syndrome (ACS) were free of coronary artery disease (CAD) by CT and had no ACS, according to ROMICAT (Rule Out Myocardial Infarction using Computer Assisted Tomography) trial results published in the May 5 issue of the Journal of the American College of Cardiology.
Udo Hoffmann, MD, from Massachusetts General Hospital and Harvard Medical School in Boston, and the ROMICAT investigators performed 64-slice coronary CT angiography (CCTA) before admission to detect coronary plaque and stenosis (greater than 50 percent luminal narrowing).
Among 368 patients (mean age 53, 61 percent men), the researchers found that 8 percent had ACS. By CCTA, 50 percent of these patients were free of CAD, 31 percent had nonobstructive disease, and 19 percent had inconclusive or positive CT for significant stenosis.
Sensitivity and negative predictive value (NPV) for ACS were 100 percent; and 100 percent respectively, with the absence of CAD and 77 percent and 98 percent, respectively, with significant stenosis by CCTA, according to the authors. Specificity of presence of plaque and stenosis for ACS were 54 percent and 87 percent, respectively.
The authors reported that only one ACS occurred in the absence of calcified plaque. Both the extent of coronary plaque and presence of stenosis predicted ACS independently and incrementally to Thrombolysis In MI (TIMI) risk score (area under curve: 0.88, 0.82, vs. 0.63, respectively).
Given the large number of such patients, early CCTA may significantly improve patient management in the emergency department.
In this blinded observational cohort study, Hoffman and colleagues demonstrated that 50 percent of patients who presented with acute chest pain to the emergency department and were at low-to-intermediate likelihood of ACS had no CAD by CCTA, a finding that has 100 percent NPV, but limited positive predictive value for the subsequent diagnoses of ACS and major adverse cardiac events.
The authors said that their data also demonstrated that CCTA can risk-stratify patients with acute chest pain and intermediate likelihood of ACS independent of cardiovascular risk factors and TIMI risk score.