"It's a really hot topic and there is a lot going on, and there is a focus on getting a better understanding about all populations," Shaw explained. "The U.S. population is getting pretty diverse, and we want a better understanding of what is different between presentations in African-American women and Hispanic women."

Shaw explained some of the specific differences in how women present to doctors or the emergency department compared to men.

"There is early evidence that women who had sudden cardiac death actually had a different etiology for that sudden death, with more plaque erosion as opposed tom plaque rupture in men," Shaw explained. "So now we are trying to follow up on that early pathologic evidence using CT angiography (CTA) to see if we can look for a different cardiac burden instead of just obstructive plaque, and to identify new detection pathways that are unique to women." 

Other non-traditional cardiac risk factors specific to women include:
   • Preterm delivery
   • Hypertensive disorders during pregnancy such as preeclampsia 
   • Gestational diabetes
   • Breast cancer treatment
   • Depression
  
"In women, we see more shortness of breath, more arm pain. Women also tend to present later on in the course of their symptom onset. Woman also have more non-constructive disease as opposed to obstructive disease, so we have to understand these sex differences that contribute to patient risk," Shaw said. 

Women have smaller blood vessels than men, so smaller amounts of plaque in the coronary arteries present more of an issue than in men. This plaque in coronary arteries and throughout capillaries can lead to microvascular disease, or play a role in ischemia with no obstructive coronary artery disease (INOCA). Women present frequently with INOCA, which has the same symptoms as a heart attack caused by a sudden obstruction in the coronary arteries. However, since there is no clear obstruction seen in imaging, patients are sometimes discharged without a full understanding that it could be INOCA. This can cause serious damage to the heart, lead to repeat hospitalizations or lead to death. 

"The presence of atherosclerotic plaque also should be a light switch that should signal the need for intensive preventive care in both women and in men. But it occurs more often in women, and this hallmark can be seen on cardiovascular CT," Shaw explained. 
 
In the past 10 years, Shaw said there also has been a growing focus on sudden coronary artery dissection (SCAD) as another under-diagnosed problem that occurs mainly in women. SCAD also presents as a heart attack, but the obstruction in the coronary vessels is caused by flaps of the vessel wall tearing and blocking blood flow rather than plaque or blood clots. 

Shaw said frequently with SCAD, the women presents and has elevated troponin levels, so is sent to the cath lab. And this can occur in younger women who may have undiagnosed fibromuscular dysplasia, or can occur in postpartum. She said these diagnosis can be made on a CT scan, so the patient does not necessarily have to undergo an interventional cath. 

"The imaging gives you an opportunity to step back and and not go to an invasive procedure, especially if it is a distal coronary SCAD, which is quite common," Shaw said. "Women can safely be triaged with CT. The evidence is still out, but keep in the back of your mind and that you don't want to send someone to an invasive coronary angiography if you don't have to."

For more on this topic, watch the related VIDEO: Gender differences in women with cardiovascular disease and implications for imagers — an interview with women's heart expert Erin D. Michos, MD.