Published: Oct. 2, 2006
Updated: May 7, 2010
About 1 million Americans suffer heart attacks each year, one third of them fatal. While often preceded by warning symptoms of coronary artery disease -- such as chest pain and shortness of breath -- many of the most fatal heart attacks occur with no warning at all.
Recently developed diagnostic techniques are greatly enhancing doctors' ability to evaluate an individual's level of risk for serious heart events, long before symptoms appear or a heart attack strikes.
Among the new tools is multislice computed tomography (CT), a painless, non-invasive screening procedure that measures the amount of potentially dangerous plaque buildup within the heart's arteries -- a precursor to dangerous heart attacks.
Blood tests of newly identified heart risk factors such as C-reactive protein (an indicator of inflammation in the body) and homocysteine (a toxic amino acid) can be combined with a CT evaluation to more precisely evaluate a person’s risk for developing heart disease. Further, lack of fitness, as measured on a routine exercise stress test, is a powerful predictor of future heart events. When these screening procedures are followed by customized treatment and lifestyle changes, those risks may be greatly reduced.
Robin Quinn knew he shouldn’t smoke. He knew his cholesterol was high and he ought to lose a few pounds. His family history carried a warning, too: His father had had a heart attack in his 50s.
The real estate broker from Kenansville was only 44, and his heart gave no sign of trouble. Still, Quinn figured he should start getting healthy. So he enrolled in the Duke Center for Living’s “Healthy Escapes” program last fall.
Quinn was taken aback when a cardiovascular CT screening he underwent before beginning the program revealed that he could be on a fast track to a heart attack. Calcium deposits in his blood vessels stood out in bright white on the images like smears of marshmallow -- revealing that Quinn’s heart was aging about 10 years faster than the rest of him.
“It got my attention,” he says. “I knew if I didn’t change my lifestyle and get these things under control, I would be just like my daddy and have a heart attack.”
By far the most common form of heart disease is coronary artery disease, a chronic condition that begins quietly, developing over many years or even decades before making its presence known. Particles rich with LDL (“bad”) cholesterol accumulate on the inner walls of blood vessels. Layer by layer, these crusty curds or “plaques” gradually shrink and harden the blood vessels, choking off the heart’s supply of oxygen-rich blood.
A fibrous cap develops over each fatty core of plaque. If that cap is very thin, the core is in danger of rupturing under stress. The blood vessels that race to the site of damage can pile up and form a clot -- triggering a heart attack, stroke, or other problems.
Coronary artery disease is usually silent until about age 40. That’s when tell-tale signs start to show up on tests. Even then, outward symptoms can take years to surface. The classic warning signs of heart disease -- chest pain, fatigue, or shortness of breath -- are usually frightening enough to get people to a doctor if they haven’t been already. But even more frightening is the fact that many catastrophic heart events occur with no warning at all.
According to William Kraus, MD, a preventive cardiologist at the Duke Center for Living, a comprehensive heart disease risk evaluation should be automatic for everyone -- men and women -- by age 40. Taking stock of your heart’s health doesn’t guarantee you won’t have a heart attack or stroke. But early detection, customized treatment, and lifestyle changes can greatly reduce that risk.
“If you could put off a heart attack from age 40 to age 80,” Kraus says, “that would be good, wouldn’t it?”
For years, doctors have used risk indicators identified in the landmark Framingham study to evaluate their patients’ likelihood of developing coronary artery disease. When Robin Quinn came to the Center for Living, the staff first looked for these warning signs, which include high blood pressure, obesity, diabetes, elevated levels of triglycerides and “bad” cholesterol, family history of early vascular disease, and smoking.
But Quinn’s Duke cardiologists went beyond the Framingham assessment, asking more specific questions and assessing the risk factors mentioned above to more precisely pinpoint his risk for a catastrophic heart event.
One of the newest ways that doctors can get a head start on heart disease is with relatively simple assessments of blood markers, waist circumference, and heart fitness on an exercise stress test.
There’s growing evidence that not just the amount of cholesterol in the blood but the size of cholesterol particles themselves can affect heart disease risk. Kraus has discovered that exercise both reduces blood cholesterol levels and positively impacts the size of the protein particles to which they’re attached, forming molecules known as lipoproteins. “Cholesterol carried by small, dense protein particles appears to cause disease more efficiently than larger, fluffier particles,” Kraus says. “Exercise actually increases the size of lipoprotein particles carrying both good and bad cholesterol. The more exercise, the greater the improvement.”
One of the most exciting new cardiovascular diagnostic tools in use at Duke is the multislice CT, which records multiple images of the heart and blood vessels at 10 times the speed of conventional CT scanners. A computer then reconstructs these visual “slices” into a 3-D image that reveals calcium buildup in the blood vessels as bright white spots that correspond to the size and distribution of plaques. Each patient receives a Coronary Calcification Score of high, medium, or low, compared to other patients of the same gender and similar age.
Robin Quinn’s score of 27 revealed that his heart was, in effect, a decade further along in accumulating atherosclerotic deposits than it should have been.
Soon afterward, Quinn spent two weeks at the Duke Center for Living, learning what he could do to help his heart. He walked, jogged, and rode a bike around the tree-shaded campus. He met with a nutritionist and received detailed guidance on how to eat better. “I enjoyed it,” Quinn says. “People in my age group are not always aware of stuff like this.”
Quinn quit his 2-pack-a-day habit, cut out caffeine, and began drinking 64 ounces of water a day. “All of a sudden, I started sleeping.”
His triglyceride count had been 700. He got it down to 300 on his own, then took medication to reduce it to 160. He’s lost 20 pounds, too.
In a year or so, Quinn plans to take a CT scan again to see how his blood vessels have responded to these healthy lifestyle changes.
“It’s like a report card that lets you see where you’re headed,” he says. “If you know this stuff has already started, you can start making changes to slow it down.”