Know your diagnostic tools: coronary calcium scan

What is a coronary calcium scan?

A coronary calcium scan is a diagnostic tool that looks for the calcium deposits in the walls arteries of the heart.

Why calcium?

Calcium can accumulate on the walls of the arteries leading to calcification. In addition to fatty deposits, calcification is a major component in the formation of plaques in the arteries. These calcifications can lead to obstruction of blood vessels which causes heart attacks, strokes and other cardiovascular disorders.

Who needs the scan?

According to the National Heart Lung and Blood Institute (NHLBI)

“A coronary calcium scan is most useful for people who are at moderate risk for a heart attack. … People at moderate risk have a 10 to 20 percent chance of having a heart attack within the next 10 years. The coronary calcium scan may help doctors decide who within this group needs treatment.”

How does a calcium scan work?

According to NHLBI, 2 machines can be used to perform calcium scan - the electron beam computed tomography (EBCT) and multidetector computed tomography (MDCT). Both these machines are attached to an x-ray machine to make detailed pictures of your heart. From the pictures, doctors can discern calcifications in the coronary arteries and determine your risk for heart problems in the next 2 to 10 years. The patient must lie quietly for 10 minutes in the scanner machine. Otherwise, the procedure is safe, easy, and pain-free.

Any recent research on calcium scans?

A recent article published in the July issue of Journal of the American College of Cardiology reported that coronary calcium scans can predict the likelihood of heart attacks, even in older adults.

“Researchers studied 35,383 adults, aged 40 to 80, in Torrance, CA and Nashville, TN, for an average of 5.8 years after having a coronary artery calcium scan. Among these research volunteers, 3,570 were age 70 or older. In total, 838 deaths were recorded, 320 in women and 518 in men. The study found the overall death risk was higher among those with higher coronary arterial calcium scores.”

Previous studies showed that calcium scans can predict overall death risk in young adults, those with diabetes, those suffering from renal failure, and smokers. This study shows that the scan is effective in measuring overall death risk in the elderly as well.

Calcium scans may currently be the best diagnostic tool that can predict the likelihood of  a heart attack. Knowing the overall death risk of a patient is important. Patients and their doctors can decide on prevention measures that can lower the risk, including diet, medications, interventions, exercise and other lifestyle changes.

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Heavy drinking: bad for both male and female hearts

Heavy drinking is bad for the heart and for the arteries. Furthermore, heavy alcohol consumption affects men and women differently - although in the long run, the effects are never beneficial. This is according to a report presented at American Society of Hypertension 2008 Annual Meeting in New Orleans, LA in May.

Men: Heavy drinking among men leads to elevated blood pressure. Chronic high blood pressure then leads to stiffening of the arteries.

Women: Among women, heavy drinking does not necessarily cause high blood pressure but they are more at risk of developing enlarged hearts with structural abnormalities.

“Women … are at greater risk of developing increased left ventricular mass and septal thickness, whereas men experience more arterial and ventricular stiffness.“

The study investigated 200 men and women in Dublin, Ireland who were patients in a hypertension clinic. The drinking habits of the patients were classified as follows:

• nondrinkers
• moderate drinkers (males: 1 to 21 units of alcohol per week; females: 1 to 14 units per week)
• heavy drinkers (males: >21 units per week; females: >14 units per week)

The patients were then followed up by blood pressure measurements, conventional ECG and tissue Doppler imaging. Pulse-wave velocity and augmentation index were used to measure arterial stiffness.

“Investigators observed in men a dose-response relationship between alcohol intake and aortic systolic and diastolic blood pressure, the augmentation index, pulse-wave velocity, and indices of diastolic function. Even among those who drank moderately, there were significant increases in aortic blood pressures and the augmentation index. These findings, however, differed from the females in the study. In women, there was a dose-response relationship between alcohol and left ventricular septal and posterior wall thickness and left ventricular mass index. Even among heavy female drinkers, there was no relationship between drinking and arterial stiffness and high blood pressures.“

The results, especially those for women, were especially surprising. For one thing, heavy drinker females do not necessarily develop hypertension. It is a common belief that it is chronic hypertension that leads to the deleterious cardiovascular effects. Women, however, are more likely to develop liver disease than men. This difference is due to the fact that women are smaller and have relatively lesser liver enzymes to metabolize alcohol.

The study, however, shows that women are not only at risk for liver disease, but for heart disease as well. In fact, for women, the bad effects are not evident in the arteries but directly in the heart itself.

The heart enlargement among heavy drinking women can eventually lead to heart failure. With this condition, the heart muscles become weaker and weaker and will eventually lose the capacity to contract.

A rise in the rate of alcohol consumption among females has been the trend in Ireland. The researchers speculate that this might be due to the country’s booming economy as well as the belief that alcohol is actually beneficial to your health.

Indeed, several recent studies have reported that light to moderate alcohol consumption may actually be good for the heart. However, it seems that we need to draw a line between moderate drinking and drinking that is harmful to our health.

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