Breast arterial calcification during screening mammography identifies women at high risk for CVD.

Routine Mammography widely recommended as screening tool for breast cancer may also help predicts the woman risk for Coronary Disease, which could lead to a potential early intervention.

Recently two studies were presented linking the amount of calcium in breast arteries to calcium build up in coronary arteries. The first study was presented in March 24, 2016 at the American College of Cardiology’s 65^th Annual Scientific Session. The study was simultaneously published online in JACC: Cardiovascular Imaging.[i]

Recently, another study was also presented at the North American Menopause Society (NAMS) 2016 Annual Meeting.[2]

Coronary artery calcification(CAC) is considered very early sign of cardiovascular disease. Several noninvasive imaging techniques have been devised to evaluate the risk of CVD of an individual namely USG, MRI and CT scan.   While MRI and sonography pick up the abnormalities in arterial anatomy caused due to atherosclerosis, CT scan rely on calcium present in the coronary artery. Although CT scan is a good screening tool to predict the calcium deposition, it requires specific types of equipment, and/or specially trained personnel in addition to the high cost incurred by patients.

Interestingly, Earlier studies have shown that Breast Artery Calcifications (BAC) is associated with increased risks of CVD similar to CAC.  Studies have also associated the presence of BAC to increased risk of metabolic syndrome. [3]

In the study published in the JACC: Cardiovascular Imaging 292 women who had digital mammography and CT scan within 1 year were included in the study. Of these, 124, or 42.5 percent, were found to have evidence of breast arterial calcification. The overall accuracy of breast arterial calcification for the presence of CAC was 70 percent, and 63 percent of those with CAC also had breast arterial calcification.[4]

The other risk assessment tools that are used to calculate risk for heart disease are from Framingham Heart Study [5] which requires you to put in your age, sex, total and HDL cholesterol levels, smoking status, systolic blood pressure, and use of any blood pressure-lowering medications to calculate risk. 

The other, the ASCVD risk estimator, uses the same information while also considering a person’s race and whether they have diabetes.[6] BAC appeared to be as strong predictor of risk for CVD, if not better than Framingham and ASCVD risk calculator.

About 70% of women who had BAC on mammogram were also shown to have CAC by CT scan of the chest. The prevalence of BAC picked up at routine screening mammography is 3%-29%.

 In the paper presented at the annual meeting of North American Menopause Society (NAMS) the lead author Dr. Schnatz presented a 10 year follow up of women in whom BAC was detected at. routine mammography from June to August 2004. Data regarding risk factors for CVD and CVD events that happened was collected at baseline and also at every follow-up.

Out of 1029 subjects recruited for the study, 112 patients had baseline BAC. Those women who had calcification at baseline were 2.3 times more likely have an CVD event as compared to those who did not have calcifications. (P = .034). They were also 3.2 times more likely to have experienced stroke in 10 years. (P = .018).

Dr. Schnatz wants to call upon the researchers to add the BAC to other risk calculation tools to improve the composite outcome.

Presently there is still no consensus on using BAC as screening test for CVD risk stratification. A large study of 40,000 subjects is still ongoing in Netherlands.

The clinical implications of this research finding:

• Radiologists and primary care physicians must be educated on the link between BAC and CAC.
• About 37 million mammograms are performed in USA annually, so they serve as double screening for cancer and heart disease too, with no extra money, time or radiation.
• Each year approximately 4 million women will be diagnosed with BAC while undergoing routine mammography in USA.  About 2-3 million of these women will have atherosclerotic disease. So the diagnosis of BAC can be used for risk stratification and preventive care treatment.
• The finding of BAC during a screening mammogram should trigger an investigation of the women’s risk for CVD and implementing aggressive strategies to modify the risk.
• The reverse is not true, that women with risk factors should be referred for mammography.

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[1]http://imaging.onlinejacc.org/article.aspx?articleID=2503388

[2] https://www.menopause.org/annual-meetings/2016-meeting/scientific-program

[3] http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1807-59322014001200841

[4] https://www.acc.org/about-acc/press-releases/2016/03/25/09/26/mammograms-another-way-to-screen-for-heart-disease?w_nav=S

[5] http://www.nhlbi.nih.gov/health-pro/guidelines/in-develop/cardiovascular-risk-reduction/risk-assessment/

[6] http://tools.acc.org/ASCVD-Risk-Estimator/