A new study determined the incidence and progression of heart calcification among South Asian Americans and compared their results with that of other ethnic groups.
Atherosclerosis, or the hardening and narrowing of arteries, is a constantly changing process. If left unchecked, it slowly blocks arteries resulting in restricted blood flow. Atherosclerosis is usually the cause of heart attacks, strokes, and cardiovascular diseases.
Several decades of research has resulted in the availability of several screening tests for the assessment of the risk of atherosclerotic cardiovascular disease. A measurement of heart calcification is one such screening test that has emerged as a reliable indicator for the cardiologists to predict who is at a higher risk of having a heart attack well before a person has any symptoms.
A coronary artery calcium scan shows heart calcification
A coronary artery calcium scan or CAC, is a test that uses a computed tomography (CT) scanner to take multiple pictures of the heart. These pictures reveal specks of calcium in the walls of the heart’s arteries. This heart calcification is an early sign of cardiovascular disease.
A coronary artery calcium score that determines the degree of heart calcification, can help the cardiologist decide if a patient needs medication, such as cholesterol-lowering drugs, statins, to reduce the risk of cardiovascular disease.
The heart calcification test may not be for everyone
The coronary artery calcium test is usually recommended for those who are at risk of heart disease based on risk factors such as diabetes, high cholesterol levels, and high blood pressure. The American Heart Association recommends that people with an intermediate risk of heart disease should be tested for coronary artery calcium.
People of a certain race or ethnic group also have a higher risk of developing cardiovascular disease. For instance, South Asians constitute 60% of patients with cardiovascular disease and are, therefore, considered to be a population at high risk of heart disease. Similarly, whites are known to have a higher prevalence of heart calcification compared with blacks, Latinos, and Chinese Americans.
MASALA trial studies heart calcification in South Asian population
The findings of an ongoing Mediators of Atherosclerosis in South Asians Living in America (MASALA) study were recently published in the Journal of the American Heart Association. In this study, the researchers from the University of California, San Francisco, evaluated 698 patients from South Asian countries, mainly India and Pakistan, living in the San Francisco and greater Chicago area.
The researchers measured heart calcification in these patients twice; once at the start of the study and then after a gap of approximately five years. The results were also compared with the rates of heart calcification in other populations from the Multi-Ethnic Study of Atherosclerosis (MESA) that is a similar trial looking into the risk factors of atherosclerosis in a diverse population of 6,800 participants from six cities of the US.
Increase in heart calcification in South Asians was similar to Caucasian men
The statistical analysis showed that South Asian men had a higher progression in heart calcification annually compared with men from other ethnic backgrounds. After taking into consideration traditional cardiovascular risk factors such as age, smoking status, hypertension, diabetes and use of cholesterol-lowering drugs, the researchers found that South Asian men had a similar annual rate of change in heart calcification as seen in white men. However, the calcification rate was much higher in South Asian men compared with black, Latino, and Chinese men. In addition, the results showed a higher incidence and progression of heart calcification in South Asian men compared to women of the same race.
Heart calcification is a strong marker of heart disease. The heart calcification and its progression over the years is a strong and independent marker of heart disease. Many studies have shown an association between heart calcification and atherosclerosis. The results of this study, in combination with past clinical trials, suggest the utility of repeat coronary artery calcium measurements in evaluating the risk of heart disease. The initial scan for measuring heart calcification is the most important measure of the risk, with little additional benefit of a repeat scan to evaluate progression of heart calcification.
The findings of this study showed that South Asian men had a greater change in heart calcification compared with men in other ethnic groups. Perhaps, that may be the reason why 60% of cardiovascular disease patients are from South Asian descent.
The researchers, however, add a word of caution regarding the generalizability of these results since the study included a small sample size from only two geographic locations and the participants were first-generation immigrants mostly from India.
Can a scan prevent heart attack or stroke?
The big question for the South Asian population is if heart calcification analysis can prevent the occurrence of heart attack or stroke? Clearly, the coronary artery calcium scan is an accurate tool to assess the risk of future heart problems for those who are uncertain about their risk of heart disease and to help them make better decisions about medications and treatment. The researchers of the MASALA study continue to work on South Asian population to find out if heart calcification measurement can accurately predict the risk of heart attack and stroke in this ethnic population.
Written by Preeti Paul, MS Biochemistry
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
