Association of an Automated Breast Arterial Calcification Score with Cardiovascular Outcomes and Mortality

Abstract

ABSTRACTBackgroundBreast arterial calcification (BAC), visible on mammograms, has emerged as a biomarker of cardiovascular disease (CVD) in women. Barriers to clinical implementation of BAC include limited studies with clinical outcomes and lack of quantification tools.MethodsThis single-center, retrospective study included women with a screening digital mammogram from 2008-2016. BAC was quantified using an automated, artificial intelligence (AI)-generated Bradley score, as a binary (Bradley score ≥5) and continuous variable. Clinical outcomes were determined via electronic medical records. Regression analyses were used to evaluate the association between BAC and outcomes of mortality and a composite of acute myocardial infarction, heart failure, stroke, and mortality. Models were adjusted for age, race, diabetes, smoking status, blood pressure, cholesterol, and history of CVD and chronic kidney disease.ResultsA total of 18,092 women were included with a mean age 56.8±11.0 years. Prevalence of comorbidities included diabetes (13%), hypertension (36%), hyperlipidemia (40%) and smoking (5%). BAC was present in 4,223 (23%). Over a median follow-up of 6 years, death occurred in 7.8% women with and 2.3% women without BAC. The composite outcome occurred in 12.4% of women with and 4.3% of women without BAC. Compared to those without, women with BAC had adjusted hazard ratios (aHR) of 1.49 (95% CI 1.33-1.67) for mortality and 1.56 (1.41-1.72) for the composite endpoint, after accounting for traditional risk factors. With a continuous BAC score, each 10-point increase was associated with higher risk of mortality (1.08 [1.06-1.11]) and the composite endpoint (1.08 [1.06-1.10]). BAC was especially predictive of future events among younger women.ConclusionBAC is significantly and independently associated with mortality and incident CVD, especially among younger women. Measuring BAC using an AI algorithm is feasible and clinically relevant. Further studies are needed to confirm these findings and to evaluate whether interventions guided by BAC improve outcomes.CLINICAL PERSPECTIVEWhat is new?Breast arterial calcification (BAC) on mammograms can be reliably quantified using a novel software based on an artificial intelligence (AI) algorithm.BAC is independently associated with an increased risk of all-cause mortality and cardiovascular outcomes. These associations held true when looking at BAC as presence, score quartile, and as a continuous value as well as after accounting for traditional cardiovascular risk factors.In stratification analysis, BAC was most predictive of all-cause mortality and cardiovascular outcomes among younger women (age 40-59 years), but still independently predictive in women aged 60-74 years.What are the clinical implications?Our data provide support for the inclusion of BAC findings on mammogram reports.Automated quantification tools and reporting methods of BAC will be critical to engagement of radiologists and implementation of reporting.While additional studies are needed to determine the appropriate clinical response, the presence of BAC should at the minimum stimulate patient-provider conversations on lifestyle changes to mitigate cardiovascular risk, especially among younger women.