| By Jonathan Wander
You might drop dead while reading this. Even if you’re a model Men’s Health reader – you eat right, your blood pressure is great over excellent and your LDL-cholesterol level is post-it-on-the-refrigerator low – you might at any minute feel that gripping pain in your chest that tells you it’s over. It’s the most confounding of all cardiac mysteries: every year, heart attacks kill thousands of men who, frankly, have no business dying.
“Although half of all heart attacks and strokes happen to healthy, middle-aged men who have normal cholesterol levels,” says cardiologist Dr Paul Ridker, “the majority of victims will have another risk factor at play – high blood pressure, diabetes, obesity or a smoking habit. If you leave your doctor’s office after being told that your cholesterol levels are low and that you’re in good shape, it does not mean you’re not at risk of a heart attack – you may have one of these other risk factors.”
In fact, your risk could actually be quite high. For years we’ve been told to watch our cholesterol numbers to help us check if we’re headed for a coronary. But now many cardiologists are saying we should be looking beyond LDL and HDL. ‘CRP’ may be the symbol that saves your life.
CRP stands for C-Reactive Protein, a naturally occurring blood chemical.
Your ultrasensitive CRP level, which can be determined by a simple, inexpensive blood test, may be the single best predictor of future heart attack or stroke. (It’s called ‘ultrasensitive’ as doctors need to measure in a special low concentration range for cardiac risk assessment.) According to the Physicians Health Study – a 19-year clinical trial of more than 20 000 doctors – high CRP can predict as much as a 300 percent increase in a person’s heart-attack risk, even if cholesterol levels are normal. Supporting ultrasensitive CRP’s diagnostic value is other landmark cardiac research, including the Framingham Heart Study, which has followed more than 5 100 participants since 1971.
“We got carried away with cholesterol,” says atherosclerosis and metabolic research specialist Dr Ishwarlal Jialal. “Now we’re catching glimpses of what’s happening in the vessel wall, which is a quantum leap in this area.”
In the history books, CRP may also stand for ‘Credit Ridker, Paul’, the man who is recognised for doing the most extensive research on CRP. Dr Ridker, a slender, dark-haired researcher in his early forties, is considered one of the top cardiologists in the world and is working to make CRP tests a standard part of your diagnostic arsenal. He’s already converted US President Bush’s doctors: they tested George W’s ultrasensitive CRP level at his last executive exam. (It turned out to be “very low”.)
“The CRP test predicts risk even after you adjust for all other cardiovascular risk factors,” Dr Ridker says. “It’s easy to use, is widely available and if patients ask their physicians for the test, they can get a better grasp of their true heart-attack risk.”
Right hook to your heart
The science behind CRP begins with a fat lip. When you get popped in the mouth, C-Reactive Protein is released to sound the alarm that there’s inflammation in the body. Something similar can happen inside your heart. Inflammation in an artery wall, which can be triggered by smoking or poor diet, causes blood levels of CRP to rise – often dramatically – in response. By itself, an inflamed artery isn’t a problem. But even those of us who have avoided eating a lot of saturated fats have some degree of plaque speckling our artery walls. Inflammation can make that plaque more likely to break loose and form a clot that causes a heart attack or stroke. Enter CRP. If elevated levels are detected early enough, steps can be taken to reduce the inflammation before any plaque is dislodged. In fact, CRP testing could identify thousands of South Africans with normal cholesterol but above-average inflammation. If you have elevated CRP (two milligrams per litre or higher) and high LDL cholesterol, the risk of a heart attack is twice as great as if you had high cholesterol alone.
“A CRP test is an invaluable window into artery inflammation,” says cardiologist Dr Eric Topol. “It’s vital in cardiac evaluation.” Another advantage of testing CRP is that doctors can warn patients of a potential problem years in advance.
“We’ve seen elevated levels 30 to 40 years before the onset of first-ever events,” says Dr Ridker. “We think that about half of the variation [in inflammation] is genetic and about half comes from environmental factors, such as smoking, poor diet, lack of exercise and obesity.” The old adage “Being overweight puts a strain on your heart” is oversimplified. The CRP phenomenon does a lot to explain why obese individuals have extremely high risks of heart disease. Scientists are not exactly sure why environmental factors cause arterial inflammation.
“We believe that they activate the cells that cause inflammation,” says Dr Jialal. “But there are no detailed studies on how.”
Ice your arteries
You already know how to treat a fat lip: apply ice and wait for the inflammation to subside. Fortunately, treating inflamed arteries is almost as easy. “The things that we know reduce heart-attack risk – a healthy diet, giving up smoking, exercise – all seem to lower C-Reactive Protein,” says Dr Ridker. Specifically, that means lowering your Body-Mass Index (BMI) to between 18.5 and 24.9, stubbing the cigs, eating fewer saturated fats and exercising 30 to 60 minutes three or four times a week. Popping low-strength aspirin may also sink your CRP. For CRP levels that lifestyle changes can’t budge, doctors can prescribe a cholesterol-lowering statin drug, such as Lipitor, Zocor or Pravachol.
“With statins you achieve a two-for-one effect,” Dr Ridker says, explaining that the drugs that lower LDL cholesterol also work as anti-inflammatories. “Even people with great cholesterol levels will be prescribed statins to lower their CRP,” adds Dr Topol.
Other drugs that lower inflammation are also being prescribed or tested. According to Dr Topol, his studies have shown that the clot-busting drug Plavix “lowers CRP substantially”; that drugs used for diabetes (such as Avandia and Actos) reduce inflammation, as do ACE inhibitors; and that high doses of niacin lower CRP while raising HDL cholesterol. For now, statins are the drugs of choice, but Dr Jialal expects others to follow. “I think we’ll see designer drugs that will directly lower CRP about 40 to 50 percent,” he says.
And in this corner...
So why isn’t your doctor telling you all this? Blame the medical bureaucracy.
In South Africa, cardiologists agree that CRP-testing is not a blanket screening test for risk of heart disease. “We would not recommend ultrasensitive CRP testing for everyone. It’s a useful adjunct test,” says cardiologist Dr Elwyn Lloyd. “If you are at risk – with high cholesterol or high blood pressure, are obese or diabetic, smoke or have a family history of heart disease – your doctor will perform an ultrasensitive CRP test. A high CRP, coupled with any of these risk factors is a warning flag. CRP is an important predictor. Although there are many reasons for CRP being elevated – arthritis is one example – studies have shown a correlation between the inflammation the test picks up on and heart disease.” Another argument is that CRP levels may be elevated for reasons other than arterial inflammation, which might result in a misdiagnosis.
“While solid evidence is rapidly accumulating for ultrasensitive CRP, there is controversy over whether the use of this test in clinical practice is ready for prime time,” says cardiologist Dr Christopher O’Donnell. “There are a number of conditions that raise CRP that have nothing to do with heart disease – most notably infections and arthritic syndromes.” But Dr Ridker remains adamant that CRP can effectively be tested in all but the sickest patients.
“It’s not for someone who’s hospitalised. But in an outpatient setting, it works fine,” he says. “I think the data is extremely persuasive that the addition of a CRP level to the usual cholesterol assessment provides a better way to predict risk of heart attack.” Dr Topol, who has routinely tested patients’ ultrasensitive CRP levels for two years, agrees that there’s no need to wait. “CRP testing is a breakthrough in the field. Don’t be on the trailing edge of optimal medicine.”
If a man is unlucky enough to have elevated CRP and high LDL cholesterol, his heart-attack risk is twice as great as if he had high cholesterol alone. |
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