THURSDAY, June 7, 2012 (MedPage Today) — Coronary CT angiography (CCTA) may resolve the spotty accuracy in diagnosing coronary artery disease in women that's seen with traditional noninvasive tests, according to a multicenter study.
In a cohort of men and women with a mean age of 57, the sensitivity of CCTA to correctly identify coronary stenosis greater than 50 percent was 96 percent in men and 90 percent in women, reported Matthew J. Budoff, MD, from Los Angeles Biomedical Research Institute at Harbor-UCLA, and colleagues.
There also was no statistical difference in the sensitivity of CCTA to correctly identify stenosis greater than 70 percent, which was 96 percent and 83 percent in men and women, respectively, according to the study published online in the Journal of Cardiovascular Computed Tomography.
Historically, women have more diffuse coronary artery disease and less obstructive plaque than men. This factor has led to differences between the sexes in the accuracy of conventional chest pain triage methods, mostly unfavorable to women.
For example, women who undergo ECG exercise tests or SPECT myocardial perfusion imaging to rule out a cardiac source of their chest pain incur a higher number of false positives compared with men, the investigators noted, adding that a false positive test generally leads to an unnecessary invasive catheter angiography exam.
But the value of CCTA in women was not clear as three previous single-center studies had found conflicting results in terms of the diagnostic performance of CCTA in women, the investigators noted.
They therefore sought to assess the efficacy of CCTA in women by analyzing data from the multicenter ACCURACY (Assessment by Coronary Computed Tomographic Angiography of Individuals Undergoing Invasive Coronary Angiography) trial.
ACCURACY examined the performance of 64-slice CT imaging to detect coronary stenosis in patients without prior disease. The trial involved 16 sites in the U.S.
Of the 227 patients in the current study, 40.9 percent were women. All patients were scheduled to undergo invasive catheter angiography.
There was no difference in the number of women and men older than 55; all other baseline characteristics were similar except more women had a sedentary lifestyle and more women were obese.
Men had a higher mean calcium score than women, and men had more single-vessel, two-vessel, and left main or triple-vessel disease than women.
Women tend to have more diffuse coronary disease, and this study exemplified that.
The lower rate of obstructive coronary artery disease at both thresholds of stenosis for women is typical of their diffuse presentation of coronary disease. A total of 10 women had stenosis greater than 50 percent compared with 45 men, while six women had stenosis greater than 70 percent compared with 25 men.
Not surprising was the low positive predictive value of CCTA found in the study (69 percent for men versus 47 percent for women), which is comparable to other studies of CCTA, particularly when the prevalence of obstructive disease is low, researchers said.
Although more women than men reported having a sedentary lifestyle (50 percent versus 22 percent), researchers found no statistically significant differences in the sensitivity of CCTA to detect stenosis at either threshold when they compared sedentary men and women, as well as nonsedentary men and women.
There also were no differences in CCTA accuracy between the sexes when researchers compared men and women above 55 years old and below 55 years old.
The specificity of CCTA to correctly identify those without disease when the threshold was 50 percent or greater stenosis was statistically equal between men (78 percent) and women (88 percent). However, at the 70 percent stenosis threshold, the specificity of CCTA favored women compared with men.
"The higher specificity seen in women could potentially lead to lower normalcy rates for invasive angiography in this patient population," Budoff and colleagues wrote.
One of the strengths of CCTA is its ability to rule out disease in the absence of significant calcification. In this study, there were no differences in the negative predictive value of CCTA in men and women at either threshold of stenosis (100 percent in men and 99 percent in women at 50 percent stenosis, and 99 percent in both men and women at 70 percent stenosis).
"From a clinical standpoint, the data analysis from the ACCURACY trial is of importance as it demonstrates that there are few relevant differences between male and female patients of similar age and clinical presentation in the diagnostic accuracy of 64-multidetector row coronary CTA," they concluded.
The study was limited by the low prevalence of coronary disease. Researchers also noted that CCTA exposes the patient to radiation. However, newer CT technology can reduce that exposure to about 1.1 mSv, which is significantly lower than SPECT perfusion imaging and catheter angiography, they said.
Last Updated: 6/7/2012