Coronary CTA may help diagnose women with CVD compared with other methods
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Cardiologists and clinicians do not often recognize the sex-specific CVD pathophysiology in women, especially when using imaging modalities to diagnose patients, according to a speaker.
Coronary CTA may provide a benefit in women compared with functional imaging for diagnosis and for treatment planning, Matthew J. Budoff, MD, FACC, professor of medicine in the division of cardiology at the Lundquist Institute at Harbor-UCLA Medical Center, said during the presentation at the virtual Heart in Diabetes Conference.
Certain challenges must be recognized when performing imaging in women, as they typically have smaller coronary artery size, smaller left ventricular chamber size and greater chest wall attenuation, Budoff said. A smaller coronary artery size can decrease the coronary segments that cannot be assessed, particularly in mid to distal coronary vessels. In addition, breast tissue and a smaller LV size can decrease diagnostic performance of myocardial perfusion imaging.
Some experts said they believe that since coronary calcium is less prevalent in women, it is less prognostic, which is not true, according to the presentation. In a study published in the European Heart Journal in 2018, Budoff and colleagues found that although women had elevated risk for CVD, their risk was similar to men based on coronary artery calcification scores.
“While calcification may be more prevalent in men, especially at earlier ages, the importance of it and the lack of it are both similarly prognostic in both men and women,” Budoff said.
This tends to change in patients with diabetes, as more men with diabetes had high CAC scores compared with men without diabetes. Although the number of women with and without diabetes with a CAC score of zero was high, there was still a significant number of women with diabetes who had CAC scores above 100, according to the presentation. Both men and women with diabetes who had high CAC scores had a higher annualized morality risk per 1,000 person-years compared with those without diabetes. This increased risk was more evident in women with diabetes.
“In diabetes, that risk gets multiplied,” Budoff said. “We know that women have this loss of cardioprotection, and it’s evidenced here even with coronary calcium scores in asymptomatic patients. For the general population, men and women are similar as far as what the implications of calcium scores are, but in persons with diabetes, women suffer even greater risk with elevated calcium scores.”
Although more research is needed in this area, Budoff highlighted that a mammogram can show breast arterial calcification.
“Most women get mammography quite frequently, and if we can get the radiologist to recognize this, this probably has significant prognostic information,” Budoff said. “It certainly has good correlation with coronary artery calcification and probably is atherosclerotic. Another opportunity that we have in women is to take an extra good look at the mammogram.”
Four common choices for noninvasive testing in symptomatic women include stress ECG, stress echocardiography, stress nuclear imaging and CTA. Unfortunately, women are often underrepresented in studies that assess CAD testing with these modalities, according to the presentation.
“It represents a big problem that we have, and it hurts us when we start thinking about women and their presentation,” Budoff said. “[Although] women present differently, their performance on these tests that were initially validated mostly in men are different.”
Exercise ECG has a higher sensitivity (68% vs. 61%) and specificity (77% vs. 70%) in men compared with women, according to a study published in The American Journal of Cardiology in 1999.
“That represents a problem,” Budoff said. “That means that we’re missing 39% of women who have obstructive disease with their chest pain, and they’re told that their treadmill [test] is normal. While we think about false positives in women, false negatives are actually a bigger issue. We have to be very cautious of how we interpret a negative exercise ECG in women.”
Some sex differences in exercise testing may be explained by a decreased sensitivity in women aged 65 years and those who are on hormone therapy, according to the presentation. This increases the rate of false positives from autonomic and hormonal influences. The fact that women have smaller coronaries can also influence this.
There is a large body of evidence for the use of nuclear imaging in women showing that there is reduced accuracy because of breast attenuation and LV size, according to the presentation. Its use is also limited due to high radiation doses.
The EVINCI study, published in Circulation: Cardiovascular Imaging in 2015, found that men and women had similar diagnostic accuracies among several imaging modalities, with coronary CTA having the highest diagnostic accuracy compared with PET, single-photon emission CT, cardiac MRI and echocardiography.
“We have a more accurate test in the form of CT angiography, but does that really translate into better results for our patients?” Budoff said during the presentation.
Functional testing such as exercise stress tests resulted in 45% true positives and 55% false positives for obstructive CAD, with no differences observed for cardiac MRI, according to the presentation.
“Functional testing leads us to false positives, and that number is even worse in women and younger patients,” Budoff said. “Functional testing has not performed that well when it comes time to go into the invasive cath lab and finding obstructive disease. If your goal is to find a woman with chest pain who needs a stent, functional testing is going to be suboptimal in that regard.”
The ISCHEMIA trial presented and published in 2019 found that patients who presented with severe ischemia had lower event rates than those with mild ischemia.
“This is counterintuitive to any common concept of ischemia testing, where patients who have high levels of ischemia actually did better in the trial,” Budoff said. “This would be like [saying to] Mrs. Johnson, ‘Good news, you have severe ischemia on your nuclear test, and you’re going to do a whole lot better than if your test was normal.’ This is a big problem.”
There are also differences in the types of plaque that women have compared with men. Women more often have noncalcified plaque, whereas men have more calcified or mixed plaque, according to the presentation.
With regard to coronary CTA, the ROMICAT II trial found that women who underwent this imaging modality compared with a standard cardiac evaluation had fewer hospital admissions, a lower total radiation dose and shorter lengths of stay compared with men.
The PROMISE trial found that patients with diabetes who underwent coronary CTA had a lower event rate compared with those who underwent stress testing up to 42 months.
CT imaging offers women several advantages, including higher diagnostic accuracy, visualization of nonobstructive disease, no issues with breast attenuation or hormones, and better prognostication, according to the presentation.
References:
- Budoff MJ, et al. Eur Heart J. 2018;doi:10.1093/eurheartj/ehy217.
- Kwok Y, et al. Am J Cardiol. 1999;doi:10.1016/S0002-9149(98)00963-1.
- Neglia D, et al. Circ Cardiovasc Imaging. 2015;doi:10.1161/CIRCIMAGING.114.002179.
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Budoff MJ. Women and CVD. Presented at: Heart in Diabetes CME Conference; Aug. 21-24, 2020 (virtual meeting).
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