NEW YORK (Reuters Health) – Among patients seen in the emergency department with chest pain, cardiac CT findings predict their risk for major adverse cardiac events (MACE) in the next 2 years, according to a report in the May issue of JACC: Cardiovascular Imaging.
In fact, CT findings add incremental prognostic value to clinical risk scores, say Dr. Quynh A. Truong, with Massachusetts General Hospital and Harvard Medical School in Boston, and colleagues
In their introduction, they explain that CT is useful in the triage of acute chest pain patients, but its prognostic utility has been unclear. To investigate, the team followed 368 patients who presented with acute chest pain but had normal initial troponin levels and ECG findings. During their index hospitalization, they underwent a standard contrast-enhanced coronary CT study using a 64-slice scanner.
The 2-year cumulative probability of MACE, defined as a composite of cardiac death, nonfatal MI, or coronary revascularization, increased with increasing degree of coronary artery disease derived from the CT scans, the researchers found.
Specifically, the MACE probability was 0% with no CAD seen on CT, 4.6% with non-obstructive CAD, and 30.3% with obstructive CAD.
Factoring in the presence or absence of regional wall motion abnormalities increased the predictive value, such that the probability of MACE rose to 62.4% in the presence of both stenosis and regional wall motion abnormalities, according to the report.
The team calculates that the c statistic (equivalent to the area under the ROC curve) for predicting MACE was 0.61 for clinical TIMI risk score, which improved to 0.84 by adding CT CAD data, and improved further to 0.91 by adding regional wall motion abnormalities.
“In acute chest pain ED patients, CT coronary and functional features predict MACE and have incremental prognostic value beyond clinical risk score,” Dr. Truong and colleagues conclude. “The absence of CAD on CT provides a 2-year MACE-free warranty period, whereas coronary stenosis with regional wall motion abnormalities is associated with highest risk of MACE.”
J Am Coll Cardiol Img 2011;4:481-491.