CT Angiography Found to Have Greater Prognostic Value Than Exercise ECG
Computed tomography coronary angiography (CTA) may have greater prognostic value than exercise electrocardiography (ex-ECG) in patients with suspected coronary artery disease (CAD), particularly in those with a low to intermediate pre-test likelihood of CAD, according to a study published June 10 in JACC: Cardiovascular Imaging.
Investigators at the University of Milan, Italy, studied 681 patients with atypical or typical angina and no history of CAD who underwent both CTA and ex-ECG. Results showed that in univariate analysis, although both ex-ECG and CTA were predictors of all cardiac events, defined as nonfatal myocardial infarction, cardiac death, and revascularization, the ex-ECG hazard ratio [HR] was 2.09, 95 percent confidence interval [CI]: 1.5 to 2.8; p < 0.0001, while the hazard risk was 10 times greater for CTA with a HR: 21.1, 95 percent CI: 14.6 to 30.5; p < 0.0001. The respective rates to predict hard cardiac events, defined as all cardiac events excluding revascularization, were HR: 1.9, 95 percent CI: 1.1 to 3.2; p = 0.02 and HR: 6.8, 95 percent CI: 3.9 to 11.0; p < 0.0001.
Multivariate analysis of the results showed that the only independent predictor of all cardiac events and hard cardiac events was the presence of ≥50 percent CAD as shown on CTA. In addition, positive CTA findings identified a shorter event-free patient survival time regardless of the presence of ischemia on ex-ECG.
The authors suggest that the CTA evaluation of coronary anatomy may be the first diagnostic tool needed for the prognostic stratification of patients with low to intermediate pre-test likelihood of CAD, and ex-ECG may be more appropriate for further prognostic stratification in a subset of patients shown to have CAD ≥50 percent on CTA. "Our study shows that CTA works well in patients with a low to intermediate pre-test likelihood of CAD, whereas its prognostic stratification becomes weaker when the patient's cardiovascular risk increases," they note.
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