New Cholesterol Treatment Guidelines: Treat Risk Not Cholesterol
- Posted on: Nov 16 2013
One cardiologist’s opinion
This past week, the American College of Cardiology and the American Heart Association released new guidelines for the treatment of high cholesterol and the prevention of heart attack and stroke. The new recommendations are a revolutionary change in how doctors should determine which patients should be on cholesterol-lowering medication and specifically how statins should be prescribed. Yet the new guidelines mostly reinforce and validate how I have been approaching patients in this regard for the past decade. The guidelines still are just that, guidelines for the population at large, but it is still important for doctors to help determine what options truly are best for an individual patient.
Rather than focusing on at which cholesterol levels should warrant cholesterol-lowering medications as in previous guidelines, the new guidelines focus on which patients are most likely to benefit from statin therapy. What the starting cholesterol lab value is or the improved value on treatment is, is not as important as using a medication proven to lower the risk of heart attack or stroke.
We have known for decades that high cholesterol is a risk factor for developing the most common type of heart disease, coronary artery disease (the higher one’s bad or LDL cholesterol, the higher the risk of having a heart attack, stroke or developing plaque in the arteries – this is known as the cholesterol hypothesis). There is also convincing evidence that cholesterol directly plays a role in promoting plaque in arteries and increasing the risk of heart attack. However, the missing piece of evidence 30 years ago was whether lowering cholesterol would lower the risk of heart attack and benefit patients. Initially there was some weak evidence that lowering cholesterol with dietary changes or medications other than statins (generally older medications used in the pre-statin era of the 1970’s and 1980’s) could modestly lower the risk of heart attack in people who already had had a heart attack and were at very high risk of having another heart attack. It was thought that lowering LDL cholesterol to a greater extent would reduce the risk of heart attacks even more significantly.
Statins lower cholesterol through a specific inhibition of a liver enzyme that normally helps create cholesterol in our bodies. Statins are more effective at lowering cholesterol than any other medication available. While no medication is totally risk-free of side effects, statins generally are well tolerated in the vast majority of patients who take them. The introduction of statins nearly three decades ago revolutionized our treatment of coronary disease and well designed studies two decades ago showed that statins could significantly lower the risk of having a heart attack in people who had already suffered a heart attack. It seemed reasonable to conclude that the more one lowered one’s cholesterol, the more one could reduce the risk of a heart attack. In fact, as newer and more potent statins became available in the last few decades, not only did cholesterol levels drop to new lows, but the risk of recurrent heart attacks in the highest risk patients appeared to drop significantly as well.
In addition, in people who had not had a prior heart attack but were considered at high risk of having a heart attack (estimated 10-year risk of greater than 20%) statins appeared to offer the opportunity to lower their risk for the first time. In fact, studies using the more powerful statins also were shown to lower the future risk of heart attack, stroke or premature death from cardiovascular disease in these patients. It seemed that the higher dose of a more powerful statin one used, the lower the risk of a heart attack. Thus, previous guidelines over the years, recommended using medications to lower the LDL to certain specific goals, which were set lower for patients with the highest risk of heart attack and stroke. As statins were the most effective way to achieve these goals, they have been the mainstay of cholesterol lowering therapy, often with doses titrated to achieve LDL goals and sometimes with other cholesterol-lowering medications added as well.
An important question in the cardiology community was whether it was the lowering of cholesterol or something specific about statins that was leading to improved outcomes in our cardiac patients – or both.
Of note, the newer cholesterol lowering medications have not yet shown a reduction in risk of cardiovascular events as statins have. For example, Zetia (ezetimibe), which lowers cholesterol very modestly via a different mechanism compared to statins but is generally a well-tolerated small pill, is part of an almost finished trial to look at this.
Statins Lower More than Just Cholesterol ~ Statins Lower Cardiovascular Risk
It is not clear how much of statins’ effectiveness can be attributed solely to their cholesterol-lowering properties. We know that statins also reduce inflammation, and atherosclerosis is clearly a chronic, low-grade, inflammatory process so lowering inflammation certainly might reduce the risk of plaque progressing or becoming unstable and leading to a heart attack. We know that statins reduce blood clotting (which is associated with heart attack and stroke risk) so statins might reduce the risk of blood clots that cause heart attack or stroke just as a daily aspirin does.
The mantra in cardiology for the last two decades with regard to LDL cholesterol was “the lower the better” and statins made it relatively easy to achieve never-before achievable low levels of LDL in many patients. However, as powerful as statins are, some patients’ LDL’s did not go as low as we thought was necessary even on the highest doses of the most powerful statins. Similarly, some patients could not tolerate higher doses of statins or even any statin at all. So we often would add other cholesterol lowering agents to a statin or use them instead of a statin when necessary.
The data is difficult to interpret as to whether it is the very low LDL levels achieved or it the use of high-dose statins that are contributing to better outcomes. It is my personal belief that the truth most likely is some of each but I admit it is hard to definitively prove this.
So we have had “goals” of achieving low LDL in order to help ensure our patients had better outcomes. The average LDL in an otherwise healthy person is around 120 to 130. Typically, in someone who had known plaque in the arteries, or was otherwise at very high risk of having a heart attack, we would aim to achieve an LDL of less that 100, no matter what their LDL was to begin with. This effectively meant that often patients ended up requiring higher doses of stronger statins. But studies also suggested that in someone who had plaque in their arteries but started with an LDL of less than 100, statins still seemed to similarly improve their outcomes. It was then thought that the highest risk patients would do better if we could get their LDL to less than 70. However, the evidence that aiming for a specific LDL goal truly improves outcomes was indirect and weak at best.
In the end, many cardiologists, including myself realized that it is most important that we focus on a goal of reducing the risk of heart attack or stroke rather than just a goal of lowering cholesterol.
Statins Are For More than Just Cholesterol~Statins Are for Arteries
My personal gestalt of all of this in the last decade was that statins were not only lowering cholesterol but they were lowering cardiovascular risk by also treating the arteries themselves. While we have uncertainty as to exactly how much of each individual mechanistic effect of statins lowered this risk, the bottom line is that statins appear to be a very effective way to help keep arteries healthy. The healthier one’s arteries are, the lower one’s risk of heart attack or stroke.
Statins for the seemingly healthy patient~Whom to treat?
Even harsh critics of the newest guidelines agree that patients at the highest risk (which is defined as greater than 20% risk of a heart attack in 10 years such as those who have symptomatic cardiovascular disease) should be on statins. The bigger debate is for those who are at intermediate or even low to intermediate risk (the newly defined group with greater than 7.5% risk)
Cardiologists have all witnessed patients who did not have high cholesterol, or were otherwise not felt to be at high risk of a heart attack, yet had an unheralded heart attack. Some of these patients were doing all the right things such as exercising and eating healthy. Many of us in the cardiology community have wondered how we could do a better job of preventing these unexpected heart attacks, or sometimes more tragically, unexpected sudden death from a heart attack in otherwise seemingly healthy individuals. Given the alluring effectiveness of statins in lowering risk in patients with known coronary artery disease, it was only natural to attempt to use statins to prevent heart attacks in those whom had elevated cholesterol but otherwise had no obvious risk.
But we also have seen people have a heart attack or sudden death as the first sign of trouble even with normal cholesterol levels. Many of us in the preventive cardiology community have turned to using imaging of arteries as a way to directly assess whether plaque is present. This can be done with either coronary calcium CT scans or carotid intima-media thickness (IMT) ultrasounds to help identify who really is at risk, especially if there was any question about if their cholesterol was high enough to warrant a statin.
In addition, we know that atherosclerosis (the process of plaque build up in the arteries) occurs over decades. We usually look only at estimated 10-year risk of having a heart attack but perhaps it is important to look at lifetime risk, especially in younger patients. If, in addition to healthy lifestyle, a medication such as a statin could reduce the lifetime risk of heart attack, stroke or premature death, then identifying the appropriate patients who could benefit from it is critically important.
During my nearly two decades in practice, I have continually tried to best assess risk in my patients to help decide which persons truly needed statins, and how aggressive to be in using statins. Having an LDL goal is probably a useful practical way to help ensure adequate achievement of the bottom line of preventing heart attacks by using appropriate and aggressive enough statin treatment. But the argument being made more and more in the last few years was that getting the appropriately higher risk patients on a statin was more important than exactly what dose and what LDL they achieved with it. This is the concept that was a leading driver in the development of the latest cholesterol guidelines that just came out. From a societal and population viewpoint, if getting to more high-risk patients with appropriate therapy could reduce the overall prevalence of heart attacks in our country, then we will have achieved an important benefit for the cardiovascular health and well-being of Americans.
So while the focus of the new guidelines is to get appropriate patients on statins, the effect likely will be that more people will end up taking statins. At the same time, it actually might also mean that some patients with modestly high cholesterol but absolutely no other risk factors might not necessarily have a high enough calculated risk to warrant statin therapy. Some expert critics of the new guidelines, worry that putting all intermediate risk patients on statins might lead to side effects and needless expense with unclear or possibly no benefit. I do not think their concern is necessarily unwarranted. However, this is where imaging arteries such as with carotid IMT or coronary calcium scans might be a more exact way to determine which arteries (and thus patients) require statins. If statins are more important in treating arteries at risk rather than just cholesterol, then understanding if one’s arteries have plaque or are prone to develop plaque might be a more accurate and logical way to determine who needs treatment and who doesn’t.
Bottom Line Thoughts of This Cardiologist
When sitting face to face with an individual patient, whom I am doing my best to assess the risk of a future heart attack, and, if the risk is high enough, reduce that risk, how do the new guidelines affect my personal practice? Frankly – not much as they confirm most of what I have already been doing. Highest-risk patients generally should be on the highest tolerated doses of the more potent statins. I still feel that checking labs periodically is a useful way to confirm the patient’s compliance with the medication, with a heart-healthy diet and for some psychological reassurance that we are going in the right direction. It helps keep both the patient and the doctor on the same page and by no means should we abandon lab tests although perhaps checking them slightly less often would be reasonable for most. For those who cannot tolerate statins at all, if their risk is high enough, it probably is still reasonable to attempt other medications at trying to lower their cholesterol as best as possible.
It also is crucial for patients to understand that there is no one magic bullet at preventing heart attack and stroke. Statins play as an important a role as do adequate control of blood pressure, stopping smoking, exercising and having a balanced heart-healthy diet. Preventing heart attacks is ultimately an odds game and a good preventive cardiologist is essentially an effective medical “bookie” for the patient. The more interventions we achieve in reducing an individual’s risk, the lower the odds of that person having a heart attack. While none of it guarantees that one can avoid a future heart attack, the more we reduce risk, the better off one likely will be.
An informed and motivated patient working with a cardiologist whom is up-to-date with the latest knowledge is the best overall strategy to help achieve the best results.
Mark K. Urman, M.D.
Cardiologists in LosAngeles
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