This issue came up twice this week.
Bill is a busy accountant. Two years ago, just after the tumult of the 2005 tax season was over, he got a CT heart scan. His score: 398 . At age 53, this was a significant score. His internist did the usual: prescribed a statin (Zocor), told him to cut the fat in his diet, and be sure to exercise. (Yawn.)
Since then, Bill quit preparing tax returns and migrated to a less harried job in corporate accounting. It took two years since his heart scan for Bill to start thinking that perhaps his doctor's advice wasn't enough. If it was, he realized, everyone on a statin drug who made these minimal lifestyle changes would be cured of heart attack risk. Clearly not the case.
So Bill enrolled in the Track Your Plaque program. Our first step: Get another heart scan.
Bill was surprised. "Why another scan? I already had one!"
I explained to Bill that atherosclerotic plaque is like money: it grows in percentages, just like money in a bank account or in a mutual fund. If, for instance, you deposit $500 in a mutual fund and it yields 5% return, then after one year you will have $550. One year later, you will have 5% x $550, or $605. Another year: $665. In other words, growth is not 10% of the original amount you deposited. Growth is compounded , year over year. That's why money, when compounded, can grow so quickly.
Atherosclerotic plaque and your CT heart scan score do the same thing: they grow by a percentage of the current plaque quantity. In fact, we use the compound interest equation to calculate the annualized rate of plaque growth. But plaque grows at the extraordinary rate of 30% per year, on average. Imagine that was the rate of return on your money. You'd be the richest man or woman on earth.
Back to Bill. Now Bill, in his defense, was on a statin drug and did make modest efforts towards a (mis-guided) low-fat diet and walking four days per week. If, on a second CT heart scan, his score was:
398 --No change. That's a success, since the expected rate of increase of 30% has been stopped. However, on his current program, this is highly unlikely. (I've seen it happen just once ever out of about 2000 people.)
250 --Pop the cork on your champagne, because Bill needs to celebrate. He has substantially reversed his plaque. Highly unlikely on the current effort.
525 --The score is higher by 30%, so it has slowed, but it surely hasn't stopped. This is the most typical result on the sort of program Bill is following.
The message: Don't delay after your first heart scan score. It plaque grows like money with a huge return, there's no time like the present to take the steps to regain control.