The skeptical cardiologist has been utilizing coronary artery calcium (CAC) scans to help decide which patients are at high risk for heart attacks, and sudden cardiac death for the last decade. As I first described in 2014, (see here) those with higher than expected calcium scores warrant more aggressive treatment and those with lower scores less aggrressive treatment.
Although , as I have discussed previously, CAC is not the “mammography of the heart” it is incredibly helpful in sorting out personalized cardiovascular risk. We use standard risk factors like lipids, smoking, age, gender and diabetes to stratify individuals according to their 10 year risk of atherosclerotic cardiovascular disease (ASCVD) but many apparent low risk individuals (often due to inherited familial risk) drop dead from ASCVD and many apparent high risk individuals don’t need statin therapy.
Previously, major guidelines from organizations like the AHA and the ACC did not recommend CAC testing to guide decision-making in this area. Consequently, CMS and major insurers have not covered CAC testing. When my patients get a CAC scan they pay 125$ out of their pocket.. For the affluent and pro-active this is not an obstacle, however those struggling financially often balk at the cost.
I was, therefore, very pleased to read that the newly updated AHA/ACC lipid guidelines (full PDF available here) emphasize the use of CAC for decision-making in intermediate risk patients.
For those patients aged 40-75 without known ASCVD whose 10 year risk of stroke and heart attack is between 7.5% and 20% (intermediate, see here on using risk estimator) the guidelines recommend “consider measuring CAC”.
If the score is zero, for most consider no statin. If score >100 and/or >75th percentile, statin therapy should be started.
I don’t agree totally with this use of CAC but it is a step forward. For example, how I approach a patient with CAC of 1-99 depends very much on what percentile the patient is at. A score of 10 in a 40 year old indicates marked premature build up of atherosclerotic plaque but in a 70 year old man it indicates they are at much lower risk than predicted by standard risk factors. The first individual we would likely recommend statin therapy and very aggressive lifestyle changes whereas the second man we could discuss taking off statins.
Neil Stone, MD, one of the authors of the guidelines was quoted as saying that the imaging technique is “the best tiebreaker we have now” when the risk-benefit balance is uncertain.
“Most should get a statin, but there are people who say, ‘I’ve got to know more, I want to personalize this decision to the point of knowing whether I really, really need it.’ … There are a number of people who want to be certain about where they stand on the risk continuum and that’s how we want to use it,”
Indeed, I’ve written quite a bit about my approach to helping patients “get off the fence” on whether or not to take a statin drug.
Full title of these new guidelines includes an alphabet soup of organization acronyms
2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Blood Cholesterol
N.B. For your reading pleasure I’ve copied the section in the new guidelines that discusses in detail coronary artery calcium.
Two interesting sentences which I’ll need to discuss some other time
-When the CAC score is zero, some investigators favor remeasurement of CAC after 5 to 10 years
–CAC scans should be ordered by a clinician who is fully versed in the pros and cons of diagnostic radiology.
–In MESA (Multi-Ethnic Study of Atherosclerosis), CAC scanning delivered 0.74 to l.27 mSv of radiation, which is similar to the dose of a clinical mammogram
-184.108.40.206. Coronary Artery Calcium
Substantial advances in estimation of risk with CAC scoring have been made in the past 5 years. One purpose of CAC scoring is to reclassify risk identification of patients who will potentially benefit from statin therapy. This is especially useful when the clinician and patient are uncertain whether to start a statin. Indeed, the most important recent observation has been the finding that a CAC score of zero indicates a low ASCVD risk for the subsequent 10 years (S220.127.116.11-1–S18.104.22.168-8). Thus, measurement of CAC potentially allows a clinician to withhold statin therapy in patients showing zero CAC. There are exceptions. For example, CAC scores of zero in persistent cigarette smokers, patients with diabetes mellitus, those with a strong family history of ASCVD, and possibly chronic inflammatory conditions such as HIV, may still be associated with substantial 10-year risk (S22.214.171.124-9–S126.96.36.199-12). Nevertheless, a sizable portion of middle-aged and older patients have zero CAC, which may allow withholding of statin therapy in those intermediate risk patients who would otherwise have a high enough risk according to the PCE to receive statin therapy (Figure 2). Most patients with CAC scores ≥100 Agatston units have a 10-year risk of ASCVD≥7.5%, a widely accepted threshold for initiation of statin therapy (S188.8.131.52-13). With increasing age, 10- year risk accompanying CAC scores of 1 to 99 rises, usually crossing the 7.5% threshold in later middle age (S184.108.40.206-13). When the CAC score is zero, some investigators favor remeasurement of CAC after 5 to 10 years (S220.127.116.11-14–S18.104.22.168-16). CAC measurement has no utility in patients already treated with statins. Statins are associated with slower progression of overall coronary atherosclerosis volume and reduction of high-risk plaque features, yet statins increase the CAC score (S22.214.171.124-17). A prospective randomized study of CAC scoring showed improved risk factor modification without an increase in downstream medical testing or cost (S126.96.36.199-18). In MESA (Multi-Ethnic Study of Atherosclerosis), CAC scanning delivered 0.74 to l.27 mSv of radiation, which is similar to the dose of a clinical mammogram (S188.8.131.52- 19). CAC scans should be ordered by a clinician who is fully versed in the pros and cons of diagnostic radiology.
In October, 2016 the skeptical cardiologist predicted that Donald Trump’s coronary calcium score, if remeasured, would be >100 . At that time I pointed out that this score is consistent with moderate coronary plaque build up and implies a moderate risk of heart attack and stroke.
Trumps’ score gave him a seven-fold increase risk of a cardiovascular event in comparison to Hilary Clinton (who had a zero coronary calcium score) .
I was able to predict this score because we knew that Trump’s coronary calcium was 98 in 2013 and that on average calcium scores increase by about 10% per year.
I pointed out that his previous score was average for white men his age and his repeat score is also similar to the average white male of 71 years.
Entering Trump’s numbers into the MESA coronary calculator shows us he is at the 46th percentile, meaning that 46% of white men his age have less calcium.We can also calculate Trump’s 10 year risk of heart attack and stroke using the app from the ACC (the ASCVD calculator) and entering in the following information obtained from the White House press briefing:
Total Cholesterol 223
LDL Cholesterol 143
HDL Cholesterol 67
Systolic Blood Pressure 122
Never Smoked Cigarettes
Taking aspirin 81 mg and rosuvastatin (Crestor) 10 mg.
His 10 year risk of heart attack or stroke is 16.7%.
Given that his calcium score is average it doesn’t change his predicted risk and the conclusion is that his risk is identical to the average 71 year old white man-moderate.
We also know that Trump had an exercise stress echocardiogram which was totally normal and therefore can be reasonably certain that the moderate plaque build up in his arteries is not restricting the blood flow to his heart.
Here is what Dr. Jackson said about the stress echo:
He had an exercise stress echocardiogram done, which demonstrated above-average exercise capacity based on age and sex, and a normal heart rate, blood pressure, and cardiac output response to exercise. He had no evidence of ischemia, and his wall motion was normal in all images. the stress echo:
The New York Times article on this issue, entitled “Trump’s Physical Revealed Serious Heart Concerns, Outside Experts Say” however, presents a dramatically worrisome and misleading narrative.
It quotes several cardiologists who were very concerned about Trump’s high LDL level, weight and diet.
It’s interesting that some of the experts quoted in the NY Times piece feel that Trump’s Crestor dose should be increased in light of the recent NY Times piece questioning whether the elderly should take statins at all.
If we have serious concerns about Trump’s heart then we should have the same concerns about every 71 year old white man because he is totally average with regard to cardiac risk. In addition he is on a statin and on aspirin, the appropriate drugs to reduce risk.
In contrast to the average 71 year old male he has had a battery of cardiac tests which show exactly where he stands cardiac wise.
Most of these cardiac tests we would not recommend to an asymptomatic individual of any age. Jackson revealed that Trump had an EKG and an echocardiogram.
His ECG, or commonly EKG, was normal sinus rhythm with a rate of 71, had a normal axis, and no other significant findings.
He had a transthoracic echocardiogram done, which demonstrated normal left ventricular systolic function, an ejected fraction of 60 to 65 percent, normal left ventricular chamber size and wall thickness, no wall motion abnormalities, his right ventricle was normal, his atria were grossly normal, and all valves were normal.
So our President has a normal heart for a 71 year old white male. This automatically puts him at moderate risk for heart attack and stroke over the next 10 years but he is being closely monitored and appropriately treated and should do well.
N.B. I see that Trump’s LDL was reported previously as 93. The current LDL of 143 suggests to me that he has not been taking his Crestor.
N.B. Below is an excerpt from my prior post which explains coronary calcium
Regular readers of the skeptical cardiologist should be familiar with the coronary calcium scan or score (CAC) by now. I’ve written about it a lot (here, here, and here) and use it frequently in my patients, advocating its use to help better assess certain patient’s risk of sudden death and heart attacks.
The CAC scan utilizes computed tomography (CT) X-rays, without the need for intravenous contrast, to generate a three-dimensional picture of the heart. Because calcium is very apparent on CT scans, and because we can visualize the arteries on the surface of the heart that supply blood to the heart (the coronary arteries), the CAC scan can detect and quantify calcium in the coronary arteries with great accuracy and reproducibility.
Calcium only develops in the coronary arteries when there is atherosclerotic plaque. The more plaque in the arteries, the more calcium. Thus, the more calcium, the more plaque and the greater the risk of heart attack and death from heart attack.
Science continued to progress in the field of cardiology in 2017. Some cardiology interventions were proven to be more beneficial (TAVR) and some less (coronary stents). A class of cholesterol lowering drugs had a big winner and a big loser. A supplement that many thought, based on observational studies, was crucial to prevent heart disease, turned out to be unhelpful. More evidence emerged that saturated fat is not a dietary villain.
From the skeptical cardiologist’s viewpoint, the following were the major scientific studies relevant to cardiology:
1. “Thousands of heart patients get stents that may do more harm than good”
Cardiologists have known for a decade (since the landmark COURAGE study) that outside the setting of an acute heart attack (acute coronary syndrome or ACS), stents don’t save lives and that they don’t prevent heart attacks.
Current guidelines reflect this knowledge, and indicate that stents in stable patients with coronary artery disease should be placed only after a failure of “guideline-directed medical therapy.” Despite these recommendations, published in 2012, half of the thousands of stents implanted annually in the US continued to be employed in patients with either no symptoms or an inadequate trial of medical therapy.
Yes, lots of stents are placed in asymptomatic patients. And lots of patients who have stents placed outside the setting of ACS are convinced that their stents saved their lives, prevented future heart attacks and “fixed” their coronary artery disease. It is very easy to make the case to the uneducated patient that a dramatic intervention to “cure” a blocked artery is going to be more beneficial than merely giving medications that dilate the artery or slow the heart’s pumping to reduce myocardial oxygen demands.
Stent procedures are costly in the US (average charge around $30,000, range $11,000 to $40,000) and there are significant risks including death, stroke and heart attack. After placement, patients must take powerful antiplatelet drugs which increase their risk of bleeding. There should be compelling reasons to place stents if we are not saving lives.
I, along with the vast majority of cardiologists, still recommended stents for those patients with tightly blocked coronary arteries and stable symptoms, which were not sufficiently helped by medications. ORBITA calls into question even this indication for stenting.
The ORBITA study investigators recruited 230 patients to whom most American cardiologists would have recommended stenting. These patients appeared to have a single tightly blocked coronary artery and had chest pain (angina) that limited their physical activity.
They treated the patients for 6 weeks with aspirin/statins/ and medications that reduce anginal symptoms such as beta-blockers, calcium-channel blockers or long-acting nitrates. At this point patients were randomized to receive either a stent or to undergo a catheteriation procedure which did not result in a stent, a so-called sham procedure.
The performance of a sham procedure was a courageous move that made the study truly double-blinded; neither the patients nor the investigators knew which patients had actually received a stent. Thus, the powerful placebo effects of having a procedure were neutralized.
Surprisingly, the study found that those patients receiving stents had no more improvement in their treadmill exercise time, angina severity or frequency or in their peak oxygen uptake on exercise.
ORBITA hopefully will cause more cardiologists to avoid the “oculo-stenotic” reflex wherein coronary artery blockages are stented without either sufficient evidence that the blockage is causing symptoms or that a medical trial has failed.
Although this was a small study with a very narrowly defined subset of patients, it raises substantial questions about the efficacy of coronary stenting. If ORBITA causes more patients and doctors to question the need for catheterization or stenting, this will be a very good thing.
2. Vitamin D Supplementation Doesn’t Reduce Cardiovascular Disease (or fractures, or help anything really).
One of my recurring themes in this blog is the gullibility of Americans who keep buying and using useless vitamins, supplements and nutraceuticals, thereby feeding a $20 billion industry that provides no benefits to consumers (see here and here).
Vitamin D is a prime player in the useless supplement market based on observational studies suggesting low levels were associated with increased mortality and cardiovascular disease
Despite well done studies showing a lack of benefit of Vitamin D supplementation, the proportion of people taking more than 1,000 IU daily of Vitamin D surged from just 0.3 percent in 1999-2000 to 18 percent in 2013-2014.
Most recently a nicely done study showed that Vitamin D supplementation doesn’t reduce the risk of heart disease.
In a randomized clinical trial that included 5108 participants from the community, the cumulative incidence of cardiovascular disease for a median follow-up period of 3.3 years was 11.8% among participants given 100 000 IU of vitamin D3 monthly, and 11.5% among those given placebo.
Aaron Carroll does a good job of summarizing the data showing Vitamin D is useless in multiple other areas in a JAMA forum piece:
Last October, JAMA Internal Medicine published a randomized, controlled trial of vitamin D examining its effects on musculoskeletal health. Postmenopausal women were given either the supplement or placebo for one year. Measurements included total fractional calcium absorption, bone mineral density, muscle mass, fitness tests, functional status, and physical activity. On almost no measures did vitamin D make a difference.
The accompanying editor’s note observed that the data provided no support for the use of any dose of vitamin D for bone or muscle health.
Last year, also in JAMA Internal Medicine, a randomized controlled trial examined whether exercise and vitamin D supplementation might reduce falls and falls resulting in injury among elderly women. Its robust factorial design allowed for the examination of the independent and joined effectiveness of these 2 interventions. Exercise reduced the rate of injuries, but vitamin D did nothing to reduce either falls or injuries from falls.
In the same issue, a systematic review and meta-analysis looked at whether evidence supports the contention that vitamin D can improve hypertension. A total of 46 randomized, placebo controlled trials were included in the analysis. At the trial level, at the individual patient level, and even in subgroup analyses, vitamin D was ineffective in lowering blood pressure.
Finally, if the Vitamin D coffin needs any more nails, let us add the findings of this recent meta-analysis:
calcium, calcium plus vitamin D, and vitamin D supplementation alone were not significantly associated with a lower incidence of hip, nonvertebral, vertebral, or total fractures in community-dwelling older adults.
3. PCSK9 Inhibitors: Really low cholesterol levels are safe and reduce cardiac events
I reported the very positive results for evolocumab and disappointing results for bosocizumab on the physician social media site SERMO in March but never put this in my blog.
As a practicing cardiologist I’ve been struggling with how to utilize the two available PCSK9 inhibitors (Amgen’s Repatha (evolocumab) and Sanofi’s Praluent (alirocumab) in my clinical practice. I would love to use them for my high risk statin-intolerant patients but the high cost and limited insurance coverage has resulted in only a few of my patients utilizing it.
The lack of outcomes data has also restrained my and most insurance companies enthusiasm for using them.
The opening session at this year’s American College of Cardiology Scientific Sessions in DC I think has significantly changed the calculus in this area with two presentations: the first showing Amgen’s “fully humanized” evolocumab significantly lowers CV risk in high risk patients on optimal statin therapy and the second showing that Pfizer’s “mostly humanized” bococizumab loses efficacy over time and will likely never reach the market.
The FOURIER study of evolocumab randomized 27, 564 high risk but stable patients who had LDL>70 with prior MI, prior stroke or symptomatic PAD to receive evolocumab or placebo on top of optimized lipid therapy. 69% of patients were recieving high intensity statin therapy and the baseline LDL was 92. LDL was reduced by 59% to average level of 30 in the treated patients. The reduction in LDL was consistent through the duration of the study.
IN 1/4 of the patients LDL was <20! These are unprecedented low levels of LDL.
Active treatment significantly reduced the primary endpoint by 15% and reduced the secondary endpoinf of CV death, MI, stroke by 20%. absolute difference 2% by 3 years.
There was no difference in adverse effects between placebo and Evo.
The next presentation featured data using Pfizer’s candidate in the PCSK9 wars and the acronym SPIRE (Studies of PCSK9 Inhibition and the Reduction in vascular Events (SPIRE) Bococizumab Development Program).
Paul Ridker presented the outcomes data for bococizumab which was actually similar to evolocumab data but given the declining efficacy and development of antibodies to the Pfizer drug over time these were very disappointing for Pfizer and I would presume their drug will never reach the market.
How will these results impact clinical practice?
I am now more inclined to prescribe evolocumab to my very high risk patients who have not achieved LDL< 70. I’m willing to do what I can to jump through insurance company hoops and try to make these drugs affordable to my patients.
I am less worried about extremely low LDL levels and have more faith in the LDL hypothesis: the lower the LDL the lower the risk of CV disease.
Cost is still going to be an issue for most of my patients I fear and the need for shared decision-making becomes even more important.
4. “Pure Shakes Up Nutritional Field: Finds High Fat Intake Beneficial.”
As one headline put it.
I recorded my full observations on this observational international study here
Here is a brief excerpt:
The Prospective Urban Rural Epidemiology (PURE) study, involved more than 200 investigators who collected data on more than 135000 individuals from 18 countries across five continents for over 7 years.
There were three high-income (Canada, Sweden, and United Arab Emirates), 11 middle-income (Argentina, Brazil, Chile, China, Colombia, Iran, Malaysia, occupied Palestinian territory, Poland, South Africa, and Turkey) and four low-income countries (Bangladesh, India, Pakistan, and Zimbabwe)
This was the largest prospective observational study to assess the association of nutrients (estimated by food frequency questionnaires) with cardiovascular disease and mortality in low-income and middle-income populations,
The PURE team reported that:
-Higher carbohydrate intake was associated with an increased risk of total mortality but not with CV disease or CV disease mortality.
This finding meshes well with one of my oft-repeated themes here, that added sugar is the major toxin in our diet (see here and here.)
I particular liked what the editorial for this paper wrote:
Initial PURE findings challenge conventional diet–disease tenets that are largely based on observational associations in European and North American populations, adding to the uncertainty about what constitutes a healthy diet. This uncertainty is likely to prevail until well designed randomised controlled trials are done. Until then, the best medicine for the nutrition field is a healthy dose of humility
I wish for all those following science-based medicine a healthy dose of humility. As science marches on, it’s always possible that a procedure we’ve been using might turn out to be useless (or at least much less beneficial than we thought), and it is highly likely that weak associations turn out to be causally nonsignificant. Such is the scientific process. We must continually pay attention, learn and evolve in the medical field.
Happy New Year to Be from the Skeptical Cardiologist the EFOSC!
The skeptical cardiologist has been in Washington, DC attending the Scientific Sessions of the American College of Cardiology for the last three days in an attempt to upgrade his cardiology knowledge and obtain CMEs for all the various areas he needs CME (echo/nuclear/CT/vascular).
I’ve written some posts for SERMO, a physician social media site, on interesting presentations from the meeting.
I’m a big advocate of coronary artery calcium (CAC) scans for helping make decisions on individual patients with intemediate risk for CAD. Several speakers at this year’s American College of Cardiology Meetings presented convincing data supporting this approach, providing more information to get patients off the fence about taking statins.
However, CAC apparently would be a useless test in the Tsimane (pronounced chee-MAH-nay) people according to a study presented at the ACC meeting and published simultaneously in The Lancet.
Researchers performed CT scans on 700 of these “forager-horticulturalist” people, indigenous to the Bolivian Amazon Rainforest and found very little calcium suggesting that they have an amazingly low rate of atherosclerosis compared to we who have to live in the industrialized world.
Obviously CT scanners are not portable so the Tsimane traveled by river and jeep from the Amazon rainforest to Trinidad, a city in Bolivia and the nearest city with a CT scanner. It took tribe members one to two days to reach the nearest market town by river, and then another six hours driving to reach Trinidad.
85% of the Tsimane people studied had CAC scores of 0. In those over age 75 years, 65% had CAC scores of 0, and just four individuals in their 80s had moderately elevated CAC (> 100). The incidence of CAC > 100 in the entire Tsimane population was 3%, which is about one tenth the prevalence in a matched industrialized population. In addition, incidences of obesity, hypertension, high glucose concentrations, and cigarette smoking were rare overall.
The Tsimane live a subsistence lifestyle that includes hunting, gathering, fishing, and farming. They don’t eat at McDonalds and the men spend almost 7 hours pers day on physical labor. Their diet consists mostly of unprocessed fiber-rich carbohydrates with rice, plantain, manioc, corn, wild nuts, and fruit composing their staples. Fat consumption is 9% of calories versus 23% in the U.S.
Supporters of plant-based diets, of course, seized on these data to support the unsubstantiated claim that meat and dairy consumption is the main cause of atherosclerosis in western civilization.
Hillard Kaplan, one of the authors and a Professor of anthropology at the University of New Mexico said:
“Their lifestyle suggests that a diet low in saturated fats and high in non-processed fibre-rich carbohydrates, along with wild game and fish, not smoking and being active throughout the day could help prevent hardening in the arteries of the heart. The loss of subsistence diets and lifestyles could be classed as a new risk factor for vascular aging and we believe that components of this way of life could benefit contemporary sedentary populations.”
However, the real cause of the low levels of coronary artery calcification in the Tsimane remains a mystery because this kind of observational study cannot establish causality. Perhaps it is the 17,000 steps a day that they walk engaging in foraging and horticulturalism. Could it be due to the absence of processed food and added sugar? The Tsimane have high levels of parasitic infections: perhaps that is protecting them.
Of two things I am certain:
-The Tsimane don’t need statins.
-I prefer my lifestyle to munching on manioc and foraging all day.
I’ve just finished watching a documentary on Netflix called The Widowmaker which alternately had me fascinated, disgusted, bored, excited, and angry.
This movie is about the treatment of coronary artery disease and what we can do about the large number of people who drop dead from heart attacks, some 4 million in the last 30 years.
The documentary, as all medical documentaries tend to do, simplifies, dumbs down and hyperbolizes a very important medical condition. Despite that it makes some really important points and I’m going to recommend it to all my patients.
At the very least it gets people thinking about their risk of dying from heart disease which remains the #1 killer of men and women in the United States.
Perhaps it will have more patients question the value of stents outside the setting of an acute heart attack. This is a good thing.
Perhaps it will stimulate individuals to be more proactive about their risk of heart attack. This is a good thing.
Take a look. Think about it. If you decide you might benefit from a coronary calcium scan of your heart let me know.
I’ll dissect this movie in detail in subsequent posts. There are a lot of inaccuracies but some fundamental and important points are made that patients need to now.
Stents do not prevent heart attacks.
Standard risk factors do not do well at predicting who will have a heart attack.
The skeptical cardiologist was in Atlanta recently visiting his Life Coach (LCOSC). Oddly enough, the wife of the LCOSC (who I’ll call Lisa) had just undergone a coronary calcium scan and it came back with a high score. Most women her age (58 years old) have a zero score but hers came back at 208 .
What is the significance of a calcium score of 208 in this case?
The CT scan for calcium (discussed by me in more detail here) focuses entirely on quantifying the intense and very specific kind of x-ray absorption from calcium. The three-dimensional resolution of the scan is such that the coronary arteries which supply blood to the heart can be accurately located and the amount of calcium in them very accurately and reproducibly added up. Calcium is not in the arteries normally and only accumulates as atherosclerotic plaque builds up over time. The build up of fatty plaque (atherosclerosis) is the major cause of coronary artery disease (CAD, sometimes termed coronary heart disease (CHD)) which is what causes most heart attacks and most death in both men and women in the U.S.
We can enter Lisa’s numbers into the online MESA calculator to see how she compares to other white 59 year old women. The calculator tells us that 72% of her peers have a zero calcium score and a score of 208 is higher than 95% of her peers. Although the 95th percentile is a good place to be for SAT scores it is not for atherosclerosis. This means substantial amount of fatty atherosclerotic plaque has built up in the arteries and puts the individual at significantly greater risk for heart attack and stroke. A calcium score of 100-300 confers a 7.7 times increased risk compared to an individual with similar risk factors with a zero calcium score.
Most of the risk factors that we can measure to assess one’s risk of heart attack (blood pressure, diabetes, smoking) were absent in Lisa. Her cholesterol levels had risen in the last 10 years but when I entered her numbers (total cholesterol 221, HDL 68) into the ASCVD risk estimator her 10 year risk came back at 2.5%. This is considered low and no treatment of cholesterol would be advised by the new guidelines.
The only clue that her cardiologist would have that Lisa has advanced premature atherosclerosis is that her mother had coronary heart disease at an early age, something we call premature CAD. Her mom at the age of 62 suffered a heart attack and had a stent placed in one of her coronary arteries. The occurrence of significant premature CAD in a parent or sibling substantially increases the chances that a patient will have premature CAD and the earlier it occurred in the parent or sibling the higher the risk.
Some of this excess risk is transmitted by measurable risk factors such as hypertension and hyperlipidemia and some through lifestyle factors but the majority of it is through genetic factors that we haven’t fully identified.
How much of an individual’s risk for heart attack is determined by genetics versus lifestyle?
A large Swedish study found that adopted men and women with at least one biological parent with CHD were 1.5 times more likely to have CHD than adoptees without. In contrast, men and women with one adoptive parent were not at increased risk.
Since 2007 an intense project to identify genetic factors responsible for CAD has been underway at multiple academic centers. Thus far 50 genetic risk variants have been identified. According to Dr. Robert Roberts
” All of these risk variants are extremely common with more than half occurring in >50% of the general population. They increased only minimally the relative risk for coronary artery disease. The most striking finding is that 35 of the 50 risk variants act independently of known risk factors, indicating there are several pathways yet to be appreciated, contributing to the pathogenesis of coronary atherosclerosis and myocardial infarction. All of the genetic variants seem to act through atherosclerosis, except for the ABO blood groups, which show that A and B are associated with increased risk for myocardial infarction, mediated by a prolonged von Willebrand plasma half life leading to thrombosis”
How well do the standard risk factors capture the individuals risk for heart attack?
The standard approach to estimating risk fails in about 25% of individuals as it does not accurately convey the high risk of the patient with family history and it overestimates risk in many elderly individuals who have an excellent family history.
It is in these patients that testing for the actual presence of atherosclerosis, either by vascular screening or coronary calcium is helpful.
Reducing The Excess Risk of Premature CAD
For many individuals there are clear-cut lifestyle changes that can be implemented once advanced CAD is identified: cigarette smoking cessation, weight loss through combinations of diet and exercise with resulting control of diabetes, However, many patients like Lisa, are non-smokers, living a good lifestyle, eating an excellent diet with plenty of fresh fruit, vegetables, fish and healthy oils and without obesity or diabetes. There is no evidence that modifying lifestyle in this group is going to slow down an already advanced progression of atherosclerosis.
Patients like Lisa have inherited predisposition to CAD, it is not due to their lifestyle.
Lisa’s cardiologist suggested she get a copy of Dr. Esselstyn’s book “Prevent and Reverse Heart Disease”. This book, based on the author’s experience in treating 18 patients with advanced CAD espouses an ultra low fat diet. The author declares that “you may not eat anything with a face or a mother (meat/poultry/fish)” and bans full fat dairy products and all oil (“not even a drop”)
Such “plant-based diets” (codeword for vegan or vegetarianism) lack good scientific studies supporting efficacy and are extremely hard to maintain long term. There is nothing to suggest that Lisa’s long term risk of heart attack and stroke would be modified by following such a Spartan dietary regimen.
Her cardiologist did recommend two things proven to be beneficial in patients with documented advanced CAD: statins and aspirin.
Taking a statin drug will arrest the atherosclerotic process and reduce risk of heart attack and stroke by around 30% as I’ve discussed here and here.
An aspirin is now indicated since significant atherosclerosis has now been documented to be present as I’ve discussed here.
We can blame a lot of heart disease on lifestyle: poor diets and lack of exercise are huge factors leading to obesity, diabetes, hypertension and hyperlipidemia, but in many patients I see who develop heart disease at an early age, lifestyle is not the issue, it is the genetic cards that they have been dealt.
Until we develop reliable genetic methods for identifying those at high risk it makes sense to utilize methods such as vascular screening or coronary calcium to look for atherosclerosis in individuals with a family history of premature CAD.
Once advanced atherosclerosis is identified, we have extremely safe and effective medications that can help individuals like Lisa deal with the cardiovascular cards they have been dealt.
The updated AHA/ACC Cardiovascular Prevention Guidelines (CPG) which include the excessively wordy “The Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults Risk” were published late last year and immediately were the center of controversy.
After working with them for 9 months and using the iPhone app to calculate my patients’ 10 year risk of atherosclerotic cardiovascular disease (ASCVD, primarily heart attacks and strokes) it has become clear to me that the new guidelines will recommend statin therapy to almost all males over the age of 60 and females over the age of 70.
As critics have pointed out, this immediately adds about 10 million individuals to the 40 million or so who are currently taking statins.
Should we be starting all elderly Americans on statin drugs?
My simple answer is no. It doesn’t make sense to do this, because clearly not all elderly individuals have atherosclerosis or will ever develop its consequences of heart attack and stroke. Many have inherited the genes that allowed their parents to live free of heart disease into their 90s and will not benefit at all from long term statin therapy; they may actually suffer the expense and side effects instead.
How can we better decide who among the elderly will benefit from statin therapy?
If you have read my previous posts on searching for subclinical atherosclerosis here and here you probably know the answer. Let’s look at a specific case and apply those principles.
Robert is 69 years old. I see him because, in 2010, the posterior leaflet of his mitral valve ruptured, resulting in the mitral valve becoming severely incompetent at its job of preventing back flow from the left ventricle into the left atrium. I sent him to a cardiac surgeon who repaired the ruptured leaflet. Although he has a form of “heart disease,” this is a form that has nothing to do with cholesterol, hypertension or diabetes and is not associated with ASCVD.
However, it is my job to assess in him, like all individuals, the risk of developing coronary heart disease or ASCVD.
He has no family history of ASCVD and he feels great since the surgery, exercising aerobically 4-5 times per week.
His BMI is 23.87 which is in the normal range. His BP runs 116/80.
His total cholesterol is 210 and LDL or bad cholesterol is 142. Good or HDL cholesterol is 56 and triglycerides 59. The total and LDL cholesterol levels are considered “high,” but they could be perfectly acceptable for this man.
When I ran his 10 year ASCVD risk (risk of developing a heart attack or stroke over the next 10 years), it came back as 14%. The new guidelines would suggest having a conversation with him about starting a statin if his risk is over 7.5%. His risk is double this and statins are definitely recommended in this intermediate risk range. Interestingly, I cannot enter a cholesterol level or blood pressure for a man of this age that yields a risk less than 7.5%.
When I had my discussion with him about his risk for ASCVD, I plugged his numbers into my iPhone and showed him the results and gave him the guideline recommendation.
Lifestyle Changes to Lower Cholesterol
The new Cardiovascular Prevention Guidelines have a section devoted to Lifestyle Management to Reduce Cardiovascular Risk. Unfortunately, none of the lifestyle changes they recommend have been shown to reduce ASCVD risk in an individual like Robert. He already exercises the recommended amount, is at his ideal body weight and eats a healthy diet. If we were to tighten up on his diet by, say reducing red meat, eggs and high fat dairy, all we would accomplish would be to lower his LDL and HDL cholesterol levels and make his life and meals less satisfying. The lower total cholesterol and LDL cholesterol would not lower his risk of ASCVD and the calculated 10 year ASCVD risk would still be in the range where statins are recommended.
Therefore, I am not going to tell Robert that he should reduce his saturated fat consumption (he already has incorporated that into his diet since he’s been bombarded with the low fat mantra for 30 years).
Searching for Subclinical Atherosclerosis
I’m going to tell Robert that we need to know if he has atherosclerosis, the disease that we are attempting to modify.
We started with an ultrasound to look at the lining of the large arteries in his neck that supply blood to the brain, the carotid arteries (a process I describe in more detail here). Although severe atherosclerotic blockages in these arteries put one at risk of a stroke, I was much more interested in the subtle changes in the arteries that precede symptoms and are an early harbinger of atherosclerosis.
Careful ultrasound recording and measurement of the main common carotid arteries from both the left and right side showed that the IMT or thickness was lower than average for his age, gender and ethnicity. His carotid IMT was at the average for a 60 year old, therefore, his so-called vascular age was 60 years, younger than his chronological age. If I plug that age into the ASCVD risk estimator, I get an 8.2% 10 year risk, just barely above the statin treatment cut-off.
Careful scrutiny with ultrasound of the entire visible carotid system in the neck on both sides did not reveal any early fatty plaques or calcium in the lining of the carotid arteries. He had no evidence for atherosclerosis, even very subtle early forms, in this large artery, a finding which is usually predictive of what is going on in the other large arteries in the body, including the coronary arteries, which supply blood to the heart.
At this point, I think, we could have stopped the search for subclinical atherosclerosis and agreed that no statin therapy was warranted. However, Robert wanted further reassurance that his coronary arteries were OK, therefore we set him up with a coronary calcium study (see my full description of this test here).
Searching for Subclinical Atherosclerosis: The Calcium Score
Robert’s coronary calcium score came back at 21 (all in the LAD coronary artery) , which put him at the 26th percentile compared to normal men of his age and gender. A score of 21 is average for a 59 year old man and 82% of men aged 69 have a score greater than zero. Robert had much less calcium in his coronaries than men his age, another factor putting him in a low risk category.
Given the low risk findings from both the vascular screening and the coronary calcium, I felt comfortable recommending no statin therapy and going against the guidelines.
Statins: Better Targets for The Two-edged Sword
This is not an unusual scenario; many of my older patients without heart attacks, strokes or diabetes fall into the risk category that would warrant statin therapy and if they have no clinical or subclinical evidence of atherosclerosis, I don’t advise statin therapy. My patients are free to follow the guidelines and take statin drugs after this advice, but most are very grateful that another pill (which they likely have heard bad things about on the internet or from friends with adverse experiences) can be avoided.
Statins are wonderful drugs when utilized in the right population, but they also carry a 9% increased risk of diabetes and about a 10% real world risk of developing muscle aches and weakness (myalgia).
I think it is essential to aim these two-edged swords at the right targets if we are to maximize the overall health benefits.
Nearly every day I see a patient in the office who has just experienced a friend or relative suddenly “dropping dead.” Understandably, they are very concerned about this and want to know “Is this going to happen to me?”
There is very good reason to be concerned. Cardiac disease is the leading cause of death in America. Despite considerable progress, regrettably 50% of deaths occur suddenly, without any previous symptoms which would have suggested a cardiac problem. It doesn’t just hit the overweight or the smoker. It not uncommonly strikes the very fit and seemingly healthy, as in the case of the St. Louis Cardinal pitcher, Daryl Kile, who was found dead in his hotel room at the age of 34. This question of who is going to suddenly drop dead (sudden cardiac death or SCD) is one of the fundamental unsolved mysteries in current cardiology.
Atherosclerosis and Dropping Dead
Most SCD in individuals over the age of 35 is related to the development of fatty plaques (atherosclerosis) in the arteries that supply blood to the heart (coronary arteries) and the subsequent sudden rupture of these plaques (thrombosis). The result of this rupture is the complete blockage of the artery and the total cessation of blood flow to a portion of the heart muscle. When that heart muscle portion becomes starved for oxygen, the muscle cells start dying and a myocardial infarction (MI) or heart attack occurs. You can view an animation of this process here With any MI, the dying muscle cells can become electrically irritable and initiate an abnormal heart rhythm called ventricular tachycardia (VT) or ventricular fibrillation (VF). This abnormal rhythm is what causes people to “drop dead” suddenly. Basically, the heart cannot pump blood efficiently in VT or VF; thus, there is no blood flowing to the brain and other vital organs. This is a long, complicated chain of events, but basically it begins with the development of fatty plaques or atherosclerosis. It makes sense that we can stop people dropping dead from MI by stopping the development and progression of atherosclerosis. Atherosclerosis develops long before any clinical signs or symptoms of disease. You can feel totally fine and have a huge build up of plaque in all of the arteries of your body. This is termed subclinical atherosclerosis. It makes sense, and it has been scientifically proven, that those with a huge buildup of plaque (high plaque burden) are at higher risk for MI and death than those with low or no plaque burden. It also makes sense that treating those patients with high plaque burden will be most beneficial.
How Do you know if you have atherosclerosis
I discussed the standard recommended method for determining risk of MI/SCD in my last post on statins. Basically, this is simply adding up the factors we know contribute to atherosclerosis: diabetes, cigarette smoking, hypertension, age, gender and cholesterol levels. However, most heart attacks and strokes occur in people who are classified by traditional risk factor scoring as low or intermediate risk. Conversely, others are misclassified as high risk and mistakenly advised to take drugs to reduce their risk factors for the rest of their lives.
How Can We Detect Subclinical Atherosclerosis?
In my office practice I offer patients two tests which directly detect and quantify subclinical atherosclerosis. One looks for plaque and thickening in the larger arteries of the neck, the carotid arteries, and one looks for calcium in the coronary arteries. I’ll go into detail about both of these in subsequent posts. For now, I will just say that the carotid screening technique uses harmless ultrasound while the coronary calcium technique uses ionizing radiation from a CT scan. Neither test is covered by insurance or Medicare. Both tests have been shown to improve our ability to identify those at risk for MI and stroke.
These tests are helpful in two general areas:
*The first scenario is the patient who appears to be at low or intermediate risk for atherosclerosis based on the risk estimator, but who has a strong family history of MI, sudden death or stroke. If we identify significant subclinical atherosclerosis in this patient, statin therapy is more likely to be beneficial.
*The second scenario is the patient who has been put on statins for primary prevention based on standard risk estimator but has no family history of ASCVD and is questioning the need for treatment. In this patient if we find no subclinical atherosclerosis, a strong argument can be made to stop the statin drug.
There is an organization dedicated to promoting the detection of SA by these tests and an algorithm for treatment called SHAPE (Society for Heart Attack Prevention and Education). Interestingly, after a female Texas state representative suffered an MI, in 2009, Texas Governor Ricky Perry signed off on the Texas Heart Attack Prevention Bill mandating health-benefit plans to cover screening tests for SA. No other state to my knowledge has such a law.
How to Stop Sudden Cardiac Death
The two tests I mentioned are a good second step towards identifying the individual at risk for MI and SCD but we still don’t know who among those with advanced subclinical atherosclerosis is going to experience a sudden rupture of plaque, have an MI and drop dead.
We need a way to identify those patients with vulnerable plaque (one that is about to rupture) and aggressively treat those patients. This is an area of intense research focus. You can view a fascinating video (accompanied by weirdly cool music) created by SHAPE here and another (featuring a gun shooting a heart) here emphasizing the importance of the vulnerable plaque.