Australia’s first study to determine the link between breast artery calcification and heart disease in women will examine emerging evidence that calcification along the walls of the arteries could mean an increased risk of cardiac disease.
Heart disease remains the world’s leading cause of death and as there is currently no available screening tool to identify women at significant risk, the research team, headed by Dr Sing Ching Lee — a medical registrar at Royal Perth Hospital and a Doctor of Philosophy Student at UWA Medical School — hope that ultimately, the already established mammography program could also be used to screen for heart disease.
The study is the result of a cooperative venture between RPH Imaging Research Fund and BreastScreen WA and is based on observational and retrospective studies (conducted globally), which seem to indicate a correlation between women who have breast arterial calcification and women who have a history of stroke, heart attack and severe cardiovascular events.
Calcification is commonly found in mammograms of post-menopausal women.
Dr Liz Wylie, the Medical Director of BreastScreen WA and Dr Lee’s colleague, said that currently it was not apparent how it could be a causal relationship.
“Why would muscular arterial calcification in the breast be related to cardiac disease,?” she said.
“The connection’s not clearly apparent at all but it does seem to be observed in a large number of observational studies around the world in a broad spectrum of populations. But the mechanism by which they would be related is unknown.”
Breast arterial calcification is thought to be a benign phenomenon related to aging and is more common in older women.
“It’s calcification in the muscular wall of the artery and quite an unusual calcification – in that it is not the same as the calcification that you see in people with cardiovascular disease: if you have disease in your carotids, which will predispose you to having a stroke or a heart attack, that calcification is in the lining of the artery.… but the calcification that we see in 12 percent of women over the age of 40, who are having a mammogram, is in the muscular wall,” Dr Wylie said.
“So, what we are trying to do now is to take a group of women who don’t have a history of stroke or cardiovascular disease and divide them into those women with breast arterial calcification, age matched with women who don’t have breast arterial calcification, and see if there are other markers of cardiac disease that are more common in one group than the other.”
Dr Lee and her team will be involved in doing clinical assessment, such as measuring blood pressure, cholesterol, and triglycerides, and performing a coronary artery calcium score CT scan to see if they have coronary artery disease.
“We want to see if these asymptomatic women are more likely to have evidence of significant cardiovascular disease if they have this calcification in their breasts,” Dr Wylie explained.
“A lot of women would have their blood pressure taken once a year at the GP and have their triglycerides measured, but the next stage of going on and having a CT calcium score, most GPs wouldn’t do that – it’s not a screening test for the whole population. But if we could triage out a group who were at higher risk, and we can prove that there is a clear benefit in doing so, then that’s a real breakthrough in prevention strategies.”
Whilst the mammography screening program begins at 40 years of age, if a younger woman presented with a large amount of arterial calcification, then one of the questions the team is looking at, is to discover if the volume of arterial calcification is an indicator of the severity of cardiac disease.
“For example, twelve percent of the population will have arterial calcification in their breast, but if we’re screening women over the age of 90, then that might be as high as 50 percent of the population – if we are screening women at the age of 40, then that figure might be three percent,” Dr Wylie explained.
“But should we be telling all of those women at 40, who have arterial calcification, that it’s important to go and see their doctor for further screening for cardiac disease? They are all unknowns at this point but those are the kind of questions that this topic raises.
“We need robust data, robust evidence that this is a strong association, and that notifying women and their GPs of a woman’s arterial calcification will be of benefit and not just lead to undue anxiety or overdiagnosis.”
The Australian study will recruit eligible women to assess their risk of heart disease at the Royal Perth Hospital Medical Research Foundation building. A selection of women aged 40 to 75 with no history of heart disease will be invited to participate while having their mammogram and during the appointment, participants will complete the following:
- a short survey of their knowledge and awareness of breast artery calcification
- a physical activity questionnaire
- a physical examination
- a heart tracing
- a blood test
- an appointment at Western Radiology for a CT scan of the heart will also be arranged
- six months after this initial appointment a follow up appointment will be conducted where the same tests, except for the CT scan, will be repeated.