Breast arterial calcification may indicate CVD risk in postmenopausal women

Breast arterial calcification (BAC), as viewed on screening mammograms, may suggest a risk of cardiovascular disease (CVD) in postmenopausal women, a recent US-based study showed.

“Our results indicate that BAC has potential utility for primary CVD prevention,” said the authors led by Dr Carlos Iribarren from the Kaiser Permanente Northern California Division of Research in Oakland, California, US.

“Our study has moved the needle toward recommending routine assessment and reporting of BAC in postmenopausal women. Integrating this information in cardiovascular risk calculators and using this new information can help improve cardiovascular risk reduction strategies,” he added.

The participants were 5,059 postmenopausal women aged 60–79 years who were enrolled in the Multiethnic Study of Breast Arterial Calcium Gradation and Cardiovascular Disease (MINERVA) cohort and who underwent screening mammography between October 2012 and February 2015 in Northern California, US. Of these, 26.5 percent had BAC (calcium mass >0 mg). Women with prior CVD or breast cancer were excluded.

Women with BAC were more likely to have prediabetes or diabetes, hypertension, and higher systolic blood pressure or HDL-cholesterol levels.

The participants were followed up for a mean 6.5 years, during which time there were 155 atherosclerotic CVD (ASCVD)* events (3.0 percent) and 427 global CVD events** (8.4 percent).

After adjustment for CVD risk factors, the presence of digital mammogram-detected BAC was associated with an increased risk of ASCVD (hazard ratio [HR], 1.51, 95 percent confidence interval [CI], 1.08–2.11; p=0.02). [Circ Cardiovasc Imaging 2022;15:e013526]

The presence of BAC was also associated with an increased risk of global CVD (HR, 1.23, 95 percent CI, 1.002–1.52; p=0.048).

A dose-response pattern with increasing BAC levels was not observed for the association with ASCVD. In contrast, a dose-response pattern was noted for global CVD in the 95^th percent threshold of BAC levels.  

Compared with women with no BAC and who were considered low risk for ASCVD (<5 percent) as per 10-year pooled cohorts equation (PCE), those with low risk and BAC were at an elevated risk of ASCVD (HR, 2.28; p=0.05). Among women in the borderline to intermediate PCE risk group (5 to <20 percent), those without BAC had a greater risk of ASCVD (HR, 2.94; p=0.0001) as did those with any BAC (HR, 4.19; p<0.0001). Additionally, women considered high risk (>20 percent) also had an increased risk of ASCVD, regardless of BAC absence (HR, 3.62; p=0.003) or presence (HR, 5.98; p<0.0001).

“BAC adds prognostic information at every level of the PCE risk. This implies that women with BAC at borderline or intermediate ASCVD risk may be candidates for more aggressive treatment, and women with BAC already at high risk may be candidates for intensification of therapy,” the authors said.

“[However,] it is really important to note that the absence of BAC did not translate into low risk and should not be falsely reassuring when no BAC is present. Optimal risk factor control is equally important for all women with and without BAC,” said Assistant Professor Sadiya Khan and Dr Natalia Cameron from the Northwestern University Feinberg School of Medicine, Chicago, Illinois, US, in an accompanying editorial. [Circ Cardiovasc Imaging 2022;15(3):e013977]

The significance of the association between BAC and ASCVD or global CVD was lost after adjusting for women not on cholesterol-lowering therapy.

The utility of BAC

“Currently, it is not the standard of care for BAC visible on mammograms to be reported [though] some radiologists do include this information on their mammography reports,” said Iribarren.

This is despite evidence suggesting a link between BAC and elevated CVD risk, the authors said. [Obstet Gynecol 2011;117(2 Pt 1):233-241]

“[In addition,] research has confirmed the calculators we currently use to assess an individual’s 10-year risk of developing CVD are not as accurate in women as they are in men,” Iribarren said. “We hope that our study will encourage an update of the guidelines for reporting BAC from routine mammograms.”

The authors noted that the results may not apply to younger women. Limited statistical power prevented assessment of individual CVD outcomes. Further research is warranted over a longer period to examine the dose-response relationship between BAC and CVD, they added.