Interview With Dr. Bradley Radwaner
You exercise, you eat right, and you feel terrific.
But - whether you are a man or a woman - you still may be at risk of heart disease, the nation's leading cause of death.
If you eat a diet high in saturated fats, or if you've inherited a tendency to accumulate cholesterol, you may develop fatty deposits along the walls of your arteries. And if you are a woman, you actually have a five times greater risk of dying from a heart attack than from breast cancer.
Dr. Radwaner is a graduate of Cornell University Medical College, completed his post-doctoral training in internal medicine at Lenox Hill Hospital, and cardiology training at Columbia University and NYU Medical Center.
An experienced invasive cardiologist, Dr. Radwaner had performed cardiac catheterization and balloon angioplasty on over 5,000 patients but now focuses on preventing heart disease. In 2001 he established The New York Center for the Prevention of Heart Disease dedicated to early detection, prevention and treatment. He is affiliated with Lenox Hill Hospital and New York Presbyterian Hospital. Dr. Radwaner is Assistant Clinical Professor of Medicine at Weil-Cornell Medical College.
Published in many medical journals, he is highly articulate, and knows how to get your attention. "Nearly one-quarter of all heart attacks are not recognized when they occur", he tells me. They are silent heart attacks, with no pain. But they're potentially even more serious than what we commonly recognize as a heart attack - because the unknowing victim has not been warned to examine his or her lifestyle, and to get appropriate medical attention."
A person can exercise, eat well, have low stress, and still have the potential for heart disease.
Dr. Radwaner: Yes. Unfortunately, a lot of people have silent ischemia, a problem with blood flow to the heart muscle.
Radwaner: It's 'silent', because though there is a problem, the heart doesn't signal the body by having chest pains. These people are unaware they have a serious problem.
People may be running for cabs, walking up stairs, or doing heavy labor at work, and not even know they're stressing their heart and doing damage to it.
Studies from John Hopkins University show that people who had silent ischemia did worse than those people who had chest pain and sought medical attention. Those with painful ischemia, or lack of blood flow to the heart, know when to stop performing a physical activity, or to avoid a situation of stress, because they feel chest pain or pressure. This is classic angina, the heart's signal it's under duress, not receiving enough oxygen.
It's the same as when you're running and get a cramp in your calf. Angina is a cramp in the heart muscle, when it's not getting enough oxygen to supply the demand.
At what age should someone get concerned about this?
Radwaner: The American Heart Association in general recommends that men and women over the age of 40 should have a stress test prior to beginning an exercise program. Certainly if they are going to engage in strenuous physical activity, like hiking or jogging, they should consider a stress test.
In the absence of chest pain or discomfort, patients with multiple risk factors for coronary heart disease should consider having a stress test to look for silent ischemia.
Each year about 350,000 Americans die suddenly with no chest pain - and at autopsy, the vast majority are discovered to have severe coronary heart disease, which has been symptom-free.
Examples of this include Dave DeBuschere, the professional basketball player and the former baseball commissioner, Bart Giametti. Neither had a history of angina or chest pain, and at ages 59 and 51 they both died suddenly of a heart attack.
Autopsy studies from the Vietnam War showed that 18 and 19 year old soldiers killed in action already had early cholesterol buildup in their arteries.
What are the risk factors?
Radwaner: They include high blood pressure, cigarette smoking, high cholesterol, diabetes, being just 30% above your ideal weight, and a family history of heart attacks before age 55 in men and before age 65 in women.
Men and women who have some of these risk factors should be looked at as candidates for hardening of the arteries. Clearly, those who have multiple risk factors, even in the absence of symptoms, should have these tests.
What tests are given?
Radwaner: One key test is the exercise stress, usually on a treadmill, but it also can be with a bicycle. On the treadmill, a patient is hooked up to an electrocardiogram while he or she goes through a graduated program of walking at different speeds and different elevations.
We watch the electrocardiogram for a response that indicates the heart is under strain, and whether or not it is receiving enough oxygen.
The second type of stress test is a nuclear stress test, where the cardiologist, often in combination with the radiologist, looks at images of the heart obtained by injecting a radioisotope during exercise and rest. This technology gives us very good pictures of the heart and its functional capabilities.
Interestingly, what we learn from the stress test does not necessarily depend on how long you exercise on the treadmill. It's more a function of what the cardiologist sees while you're exercising. A person who is in shape could still have unsuspected silent ischemia.
Recently we have found that more than 50% of the 1.5 million people who have a heart attack each year, have normal levels of cholesterol. Using an advanced lipid analysis which I do in my office through the Berkley Heart Lab in California, we can identify many of the otherwise hidden risk factors that do not show up on standard cholesterol tests, including small LDL, HDL size, CRP, LPA and homocysteine. Studies at Stanford, Emory and Quebec have shown that the size of the LDL particle, which is determined genetically for the most part is a major coronary risk factor. Small, dense LDL infiltrates more easily than larger particles into the lining of the arteries and builds up cholesterol blockages very quickly. Medication and exercise addressed against small LDL excesses can save lives.
Are there any other tests?
Radwaner: Yes. We now have ultrafast CAT scans that can measure the amount of calcium in the coronary arteries, a marker for cholesterol buildup. Patients who have higher calcium scores have been shown to have a higher probability of heart attacks over the next 4 years independent of their cholesterol level. In addition, 3D CT angiography, a new technology, allows us to noninvasively image the coronary to see the earliest blockages. Before this technology, an invasive angiogram would have been needed. Soon 70% of angiograms will be replaced by 3D CT angiograms done noninvasively.
People know men are at risk, but women above a certain age also are at risk.
Radwaner: By far, heart disease is the leading cause of death for women: 247,000 women die of heart attacks each year. By comparison, about 40,000 women die each year from breast cancer, about 41,000 from lung cancer.
In addition, women who have heart attacks are twice as likely as men to die within the first few weeks.
Unfortunately, most studies done in the lat 25 years were based only on men. But now, doctors have been giving more emphasis to heart disease in women.
Women are less at risk before menopause, because their estrogen seems to raise 'good' HDL cholesterol to protective levels, preventing development of coronary heart
disease. So, though a lot of women who are pre-menopausal might have high cholesterol levels, they also have high HDL, and therefore, are at less risk.
Cigarette smoking remains the major risk for coronary disease in pre-menopausal women. Whereas one in nine women aged 45 to 64 has some form of heart or blood vessel disease, this rate rises to one in three by age 65 and over.
Once women lose their estrogen, they rapidly catch up with men over a 10-year period. In fact, the incidence of heart attacks in post-menopausal women, and in men of the same age, rapidly becomes similar within several years.
What about diet?
Radwaner: Saturated fats are pervasive in the foods we buy in markets and especially what we eat in most restaurants. These fats are primarily found in animal foods and in some vegetable products, such as avocados and tropical oils, like coconut and palm.
Also, dairy products contain predominantly saturated fats. These fats actually raise your serum cholesterol, contributing more to coronary artery disease than eating an equal amount of cholesterol.
Polyunsaturated fats are predominantly found in vegetable and fish products. They do not contribute to hardening of the arteries. And the good news is that there is a lot of evidence that diets high in polyunsaturated fats can actually lower your serum cholesterol, slowing the development of coronary artery disease.
In reality, every fat is usually some combination of saturated and polyunsaturated, so you have to look at the ratio. You want to have more polyunsaturated relative to saturated fats. The higher the ratio, the better it is.
Certain oils, like sunflower and safflower, are higher in polyunsaturated fats than say, corn oil, while olive oil is a monosaturated fat.
Most evidence on monosaturated fat seems to indicate it is either neutral or actually lowers serum cholesterol, thus contributing less to hardening of the arteries.
What about cholesterol?
Radwaner: In addition to determining the level of cholesterol, we need to break it down, determining how much is 'good' and how much is 'bad'. LDL cholesterol levels above 100 are clearly now associated with a higher risk of heart disease. Recent studies have shown that in patients with coronary disease, LDL levels in the 60s or lower brought down with medication have the best survival and lowest incidence of new events.
New advanced lipid analysis not only identified LDL (bad) and HDL (good) cholesterol levels, but also looks at particle size. We know that those patients who make a predominance of small LDL particles have a 300% greater risk of developing coronary blockages than those who predominantly make large LDL cholesterol particles. Large HDL particles are involved in reverse cholesterol transport, moving cholesterol away from the heart and storing it safely in the liver. With exercise and certain medications, the particle size can be dramatically improved.
I thought all cholesterol was bad.
Radwaner: No, not really. HDL is the good cholesterol. It removes cholesterol from the lining of the coronary arteries, particularly the large HDL particles.
Remember that the arteries are less than one-half inch in diameter, and some are as small as one-quarter inch. So over 40 or 50 years, it doesn't take much to block off an artery and reduce the blood flow.
But the HDL acts as a scavenger, a 'scrubber', taking the cholesterol away from the arteries, and putting it in the liver. When you have a high level of LDL, the bad cholesterol, it ends up deposited in the lining of the coronary arteries. Small LDL is the worst.
In the Framingham, Massachusetts heart study, where they followed thousands of men and women for over 30 years, high triglycerides also were found to be an independent cardiac risk factor. In particular, someone with a high triglyceride level, and a low HDL, is in the group we've observed as having the greatest number of heart attacks. We now need to also pay close attention to triglyceride levels and particle size.
The Metabolic Syndrome is a very common and very high risk syndrome for heart attacks that consists of obesity, hypertension, latent or actual diabetes, high triglycerides and a predominance of small LDL particles.
In 1999 - 2000 the National Health and Nutrition Examination Survey estimated that 64% of U.S. adults are either overweight or obese (more than 30 lbs above their ideal weight). This obesity epidemic is strongly linked to the increasing incidence of adult onset diabetes in America.
What can a person do?
Radwaner: Unfortunately, the strongest risk factor, genetics, you can't do anything about. In terms of foods, you can avoid saturated fats and cholesterol - butter, egg yolks and red meat.
Of course, one problem with saturated fats is that they taste good. That's why we love French fries, potato chips, hamburgers, and hot dogs. They're filled with saturated fats, and to the American palate, that's very tasty. You have to retrain your palate away from wanting all that fat, and instead learn to love vegetables, fruits, fish, grains and pastas.
In addition, there are now excellent, safe medications to dramatically lower cholesterol, which a cardiologist can prescribe. For every 1% reduction in your blood cholesterol, you reduce your risk of having a heart attack over the next five years by 2%. With combination medication directed by the Advanced Lipid Analysis and a 3D CAT scan, I can now prevent 90% of cardiac events over a 10 year period of time.
Also, regular exercise, such as jogging or bicycling at least 20 minutes three times a week, has been shown to both raise HDL cholesterol and also to lower the risk of heart disease. Weight loss through eating a healthy, low-fat diet and regular exercise is key in reducing cholesterol levels.
What about stress?
Radwaner: We all live with stress, particularly in New York, and there is really no good evidence that it alone can cause coronary artery disease. But if you already have coronary disease, with cholesterol-filled vessels, and are then under stress, you clearly run a higher risk of having your coronary artery close off completely, causing a heart attack.
The key is prevention. Here at The New York Center for the Prevention of Heart Disease, we would much rather identify the person at risk before they have a heart attack or stroke and prevent it from ever occurring.