In writing about science-based medicine, we give a lot of attention to medicine that is not based on good science. We use bad examples to show why science is important and how it is frequently misapplied, misinterpreted, misreported, or even wholly rejected. It’s a pleasure, for a change, to write about a straightforward example of the best of science-based medicine in action. The book Heart 411 is such an example.
The medical literature is a jungle of conflicting and complicated studies. It’s difficult for novices and even for sophisticated non-specialists to navigate. It’s useful to have experts as guides who can apply their knowledge, experience, and judgment to analyze the data and put everything into perspective. I can’t imagine anyone more qualified as guides to “matters of the heart” than the authors of this book. Heart surgeon Marc Gillinov and cardiologist Steven Nissen practice at the Cleveland Clinic, which has been ranked as the number one heart hospital by U.S. News & World Report for the last 15 years and is currently ranked 4th best hospital overall. They have treated more than 10,000 heart patients over 30 years of clinical practice and have also done extensive research and published hundreds of articles in peer reviewed journals. Their book contains everything they would like their patients to know about the prevention, diagnosis, and treatment of heart disease. It amounts to an owner’s manual for the heart.
They begin with a valuable explanation of different levels of evidence and how to spot flaws in clinical studies, covering everything from surrogate endpoints to publication bias. They go on to cover risk factors old and new, the role of cholesterol, weight, diet, exercise, how tests are done and when they are not indicated, stents vs. surgery, heart failure, arrhythmias, sex differences, children, and predictions about future advances in the field. I was amused by one chapter title: “Vitamins and supplements: Trick or treatment?” recalling the title of Singh and Ernst’s book.
The book is a goldmine of information. Here is a sampling of just a few of the items that caught my eye for one reason or another:
- Only 20% of our cholesterol comes from diet; the liver manufactures the other 80%.
- Forget about special lipid tests: the standard lipid panel tells you all you need to know.
- Statins are incredibly useful but some are more effective than others.
- Red yeast rice is a “natural” alternative to prescription statins that is risky because dosage is uncontrolled and 1/3 of products contain chemicals that are toxic to the kidneys.
- A “low fad” diet is best for weight loss; calories matter, not the proportions of macronutrients. The Ornish, Esselstyne and Pritikin diets are not recommended: they explain why.
- Saturated fats in the diet contribute to heart disease; studies showing otherwise are flawed because they only compared high fat diets to other unhealthy diets.
- The first coronary angiogram was an accident.
- Cardiac catheterization via the wrist is safer than via the groin, but only 10% are done by that route in the U.S. compared to 60% in Europe.
- Chelation for heart disease is nothing but “a wallet biopsy” and is dangerous.
- Stents do not prevent heart attacks; they only limit damage from heart attacks in progress.
- Surgical checklists save lives: make sure your surgeon uses them.
- A normal heart ejects at least 50% of the blood from the ventricle with each heartbeat; but some patients function well with an ejection fraction as low as 10%.
- One type of LVAD (left ventricular assist device) pumps the blood continuously, so these patients do not have a pulse!
- Mixing supplements with prescription drugs is as dangerous as mixing drinking and driving.
- If vitamins and supplements are going to be used as medicines, they must be tested using the same rigorous standards we use for prescription drugs.
- The data on fish oil are questionable. If you’re going to take it, they recommend a specific brand: Carlson Super Omega 3.
- They disagree with the American Academy of Pediatrics and would not use statins in children under the age of 13 even if they are at high risk from familial hypercholesterolemia.
- The deficits of so-called “pump brain” after open heart surgery are probably not attributable to the pump.
- Eliminating cardiovascular disease would increase life expectancy by 7 years, compared to 3 years from eliminating cancer
- Although existing studies are not definitive, the evidence indicates that the Mediterranean diet is probably the best diet for heart health.
The book validates what I had previously written about heart disease, statins, diet, weight loss, and other subjects. I was reassured to know I’d gotten those things right, but I also learned a number of new things from it. They clarified one point I had been wondering about. Why do cardiologists tell patients to limit their egg intake when most of our cholesterol is manufactured in the liver? They explain that there are good reasons to restrict cholesterol and saturated fat in the diet, even for patients on statins: the contribution of diet is small but still significant, and a low fat diet permits a lower dose of statins, minimizing the risk of side effects.
The stress is on prevention: they estimate that 90% of heart attacks are preventable. They would be glad to be put out of business. They say
Don’t worry about us; we will gladly hang up our scalpel and stethoscope if we can find a better way to lead you to a heart-healthy life.
The book was written for the general public but is equally appropriate and informative for doctors and scientists. The promotional material says “If you have a heart, you need this book.” Even if you don’t “need” it, I certainly think you would find it worthwhile, whether you are a layman or a doctor treating heart patients.
This article was originally published in the Science-Based Medicine Blog.