Study on Heart Calcification in South Asian Americans
Overview of Atherosclerosis
A recent study examined the incidence and progression of heart calcification among South Asian Americans, comparing the results with other ethnic groups. Atherosclerosis, which involves the hardening and narrowing of arteries, is a dynamic process that can lead to blocked arteries and restricted blood flow if not addressed. This condition is a primary cause of heart attacks, strokes, and various cardiovascular diseases.
Screening for Atherosclerotic Cardiovascular Disease
Decades of research have led to the development of several screening tests that assess the risk of atherosclerotic cardiovascular disease. One such test is the measurement of heart calcification, which serves as a vital indicator for cardiologists to identify individuals at higher risk of heart attacks before any symptoms arise.
Understanding Coronary Artery Calcium Scan
The coronary artery calcium (CAC) scan is a diagnostic test that employs a computed tomography (CT) scanner to capture multiple images of the heart. These images reveal small calcium deposits in the arterial walls, indicating early signs of cardiovascular disease. The coronary artery calcium score, which quantifies the extent of heart calcification, assists cardiologists in determining whether patients require medications like statins to mitigate cardiovascular disease risk.
Who Should Undergo the Test?
The coronary artery calcium test is typically recommended for individuals at risk of heart disease based on factors such as diabetes, high cholesterol, and hypertension. The American Heart Association suggests that individuals with intermediate risk should undergo testing for coronary artery calcium.
Certain ethnic groups are also at a higher risk for cardiovascular disease. South Asians, for instance, account for 60% of cardiovascular disease patients, marking them as a high-risk population. In contrast, research indicates that white individuals exhibit a greater prevalence of heart calcification compared to black, Latino, and Chinese Americans.
Insights from the MASALA Trial
The ongoing Mediators of Atherosclerosis in South Asians Living in America (MASALA) study recently published findings in the Journal of the American Heart Association. Researchers from the University of California, San Francisco, evaluated 698 patients of South Asian descent, primarily from India and Pakistan, residing in the San Francisco and greater Chicago areas.
Heart calcification was measured twice in these patients: once at the beginning of the study and again approximately five years later. Results were compared with heart calcification rates from other populations in the Multi-Ethnic Study of Atherosclerosis (MESA), which analyzed risk factors of atherosclerosis among 6,800 participants across six U.S. cities.
Comparative Analysis of Heart Calcification Rates
Statistical analysis revealed that South Asian men experienced a higher annual progression of heart calcification compared to men from other ethnic backgrounds. When accounting for traditional cardiovascular risk factors like age, smoking, hypertension, diabetes, and cholesterol-lowering drug use, South Asian men exhibited an annual rate of change in heart calcification comparable to that of white men. However, their calcification rate was significantly higher than that of black, Latino, and Chinese men. Additionally, the study found a greater incidence and progression of heart calcification in South Asian men compared to women of the same ethnicity.
Significance of Heart Calcification
Heart calcification is a strong and independent marker of heart disease. Numerous studies have established a link between heart calcification and atherosclerosis. The findings from this study, along with previous clinical trials, highlight the importance of repeat coronary artery calcium measurements for evaluating heart disease risk. The initial scan is crucial for assessing risk, while additional scans offer limited benefits for monitoring progression.
The study indicated that South Asian men showed greater changes in heart calcification relative to men in other ethnic groups, potentially explaining why 60% of cardiovascular disease patients are of South Asian descent. However, researchers caution that the generalizability of these findings may be limited due to the small sample size and focus on first-generation immigrants primarily from India.
Potential for Preventative Measures
An important question for the South Asian population is whether heart calcification analysis can prevent heart attacks or strokes. The coronary artery calcium scan serves as an accurate tool for assessing future heart problem risks for those uncertain about their heart disease risk, aiding in informed decisions regarding medications and treatment. The MASALA study researchers continue to investigate whether heart calcification measurements can reliably predict the risk of heart attacks and strokes within this ethnic group.
Reference
Alka M. Kanaya et al., Incidence and Progression of Coronary Artery Calcium in South Asians Compared with 4 Race/Ethnic Groups. J AM Heart Assoc. 2019;8:e011053. DOI: 10.1161/JAHA.118.011053