The Evolving Science of Reducing Cholesterol
Craig Hametz, MD
How do you classify your patients?
We divide cholesterol management into primary and secondary prevention. For patients who do not have heart disease, we assess risk factors, provide therapies and offer lifestyle guidance. That’s primary prevention.
For patients who have established heart disease, we look to prevent recurrences using medicines like statins. The specific medicines prescribed depend upon whether we’re focusing on primary or secondary prevention.
How useful are statin drugs for controlling cholesterol?
We have 30-40 years of data in patients with heart disease that this class of medicine can reduce cardiac events and prolong life with a disease-free state. If you’ve had stents or a bypass, taking a statin can be protective. However, why do these drugs help? This is debated. They do lower cholesterol, but they also have pleiotropic effects, meaning they provide multiple benefits at once.
For instance, they are thought to have anti-inflammatory properties. And in the setting of an acute heart attack, giving someone a high dose statin improves outcomes, but not necessarily because the drug is lowering cholesterol numbers. Statins do not reverse plaque: they stabilize patients by decreasing the risk of events, and decreasing the risk of further interventions.
Other than statins, are there other cholesterol-lowering drugs?
A new class of medicines called PCSK9 Inhibitors recycle LDL receptors and thus markedly lower LDL numbers. When the FDA approved PCSK9 Inhibitors, we knew that they lowered the LDL number and that they were safe to take. Further research showed that they also do decrease cardiovascular event rates. It’s important to distinguish between what statins, PCSK9 Inhibitors and other drugs do directly—lowering cholesterol numbers, for instance—and patient outcomes. Our goal isn’t just managing metrics; we want to improve and save lives.
What are some of the primary causes of risk cholesterol profiles?
Dietary carbohydrate intake is one of the biggest issues facing cardiology care. We’re in the midst of an epidemic of diabetes, because we have a stagnant lifestyle and too many easily processed carbs in our diet. This type of diet/lifestyle causes HgA1c levels to go up and increases diabetes risk—and diabetes is one of largest cardiovascular risk factors.
There definitely is a shift in conventional wisdom about the effect of dietary intake of cholesterol from natural sources on the cholesterol numbers from the lab. The new thinking is that there’s less of a negative impact than what people believed a generation ago.
The numbers we’ve been told to watch seem to change over time. Why?
The metrics cardiologists care about change, because the science evolves. For instance, previously, we thought that the ratio of HDL (the “good” cholesterol) to triglycerides was important to watch. The higher the HDL and lower the triglycerides, the better. But new data pushed us away from thinking that raising HDL levels through medical therapy improves health. High HDL can signify good health, but raising that marker with medication won’t necessarily improve outcomes. Niacin based compounds that raised HDL, for instance, did not improve outcomes according to studies. However, bringing up HDL through exercise does seem to improve risk.
Higher triglycerides, meanwhile, were previously thought to be associated with higher risk for heart attacks and stroke. But more recent studies suggested that high triglycerides do not actually increase cardiovascular risk. So medical therapies addressing high triglycerides were scaled back.
Cardiologists’ guidelines also evolve. The recommendations used to set LDL goals based on number. Now, we incorporate a risk calculator that considers race, gender and other factors. You enter information into the calculator, which determines long term cardiac risk and suggests whether you should be on statin therapy. A combination of these previous and current cholesterol guidelines is important to determine whether statin therapy is appropriate for each particular patient.
What other diagnostic tools do you have? For instance, how useful is the Coronary Artery Calcium score?
Coronary Artery Calcium (CAC) scoring is an invaluable and an underutilized component for risk-stratifying patients. The CAC score tells us a number that has prognostic implications. If it’s zero, you have a low likelihood of developing a problem in the near term. If you have a high score in the 400’s, that has more significant implications.
As research into testing and metrics continues, we need to continue to focus on concrete endpoints—outcomes. A number does not matter—or at least, it does not matter as much—without an outcome.
NewYork-Presbyterian Medical Group Hudson Valley
1978 Crompond Rd.
Cortlandt Manor, NY 10567