Tag Archives: ASCVD risk

Coronary Artery Calcium Scan Embraced By New AHA/ACC Cholesterol Guidelines: Will Insurance Coverage Follow?

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.

I recommend reading “Are you on the fence about taking a statin drug” to understand the details of using CAC in decision-making and the follow up post on a compromise approach to reducing ASCVD risk.

Deriskingly Yours,

-ACP

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 

-4.4.1.4. 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 (S4.4.1.4-1–S4.4.1.4-8). 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 (S4.4.1.4-9–S4.4.1.4-12). 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 (S4.4.1.4-13). With increasing age, 10- year risk accompanying CAC scores of 1 to 99 rises, usually crossing the 7.5% threshold in later middle age (S4.4.1.4-13). When the CAC score is zero, some investigators favor remeasurement of CAC after 5 to 10 years (S4.4.1.4-14–S4.4.1.4-16). 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 (S4.4.1.4-17). A prospective randomized study of CAC scoring showed improved risk factor modification without an increase in downstream medical testing or cost (S4.4.1.4-18). 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 (S4.4.1.4- 19). CAC scans should be ordered by a clinician who is fully versed in the pros and cons of diagnostic radiology.

Downloaded from http://ahajournals.org by on November 11, 2018

from Grundy SM, et al.
2018 Cholesterol Clinical Practice Guidelines

What Happens To Cholesterol Levels When You Switch To Low Or Non Fat Dairy

When individuals  discover that they have abnormal  cholesterol readings they are often told to initiate  lifestyle changes to try to correct them.

Based on what physicians and patients have been taught  over the last twenty years, the likely dietary change recommended and the easy , first step is likely  to be to cut back on dairy fat.

IMG_6135
Yoplait Original-25% Less Sugar.(but still with 18 grams per 6 oz serving). A typical supermarket/doctor’s lounge yogurt with lots of ingredients added in (sugar, modified corn starch, Vitamin A Acetate, Vitamin D3)to replace the natural good taste and nutrients found in dairy fat.
IMG_6272 (1)
Traders Point Creamery plain yogurt. Ingredients= milk and cultures. Taste =fantastic. Grams of sugar=zero.

After all, it’s a pretty easy transition to start using skim milk and non fat yogurt because these line the supermarket shelves and have been filled with chocolate or added sugar to taste more palatable.

You might miss the great taste that butter adds to bread or cooking but for your health you would be willing to switch to non butter spreads and cut down on the cheese in your diet because  based on what you have heard from numerous media sources this is a giant step toward reducing your cholesterol numbers.

 

 

 

 


 

Unfortunately, it is a horribly misguided  step.

Although, the switch to low or non fat dairy lowers your cholesterol numbers, it is  not lower cholesterol numbers that you want: what you want is a lower risk of developing stroke or heart attack or the other complications of atherosclerosis.

Let me repeat: Don’t worry about your cholesterol numbers, worry about your overall risk of developing heart attack or stroke.

Due to 30 years of misinformation, the concept that lowering your cholesterol means lower risk of heart disease has become firmly entrenched in the public’s consciousness-but in the case of dietary intervention this has never been documented.

I take care of a 69 year old woman who has an abnormal heart rhythm and chest pain. As part of her evaluation for chest pain we performed a coronary CT angiogram (CCTA) which showed advanced but not obstructive atherosclerotic plaque in her right and left anterior descending coronary arteries.

This lady was not overweight, followed a healthy diet and exercised regularly. Her mother, a sedentary, heavy smoker, suffered a heart attack at age 54.

Her PCP had obtained lipid values on her 6 months before I saw her which were abnormal but the patient had been reluctant to start the recommended statin drug because of concerns about side effects.

After seeing her CCTA I advised that she begin atorvastastin 10 mg daily and aspirin to help reduce her long term risk of heart attack, stroke.

She decided without telling me not to take the statin, again due to side effect concerns, but started the aspirin, and began to pursue what she felt were healthy dietary changes.

When I saw her back in the office she told me  “I don’t eat butter or cheese anymore and I’ve switched to skim milk.” She had substituted olive oil for butter.

Here are her lipid values before and after her dietary changes (TC=total cholesterol, LDL= bad cholesterol, HDL=good cholesterol, trigs=triglycerides)

Date              TC             LDL       HDL   trigs            ASCVd 10 year risk

3/2015         275          173       72       149                         7.9%

10/2015      220           122       43      274                         8.3%

At first glance, and especially if we focus only on the total and bad cholesterol, this appears to be a successful response to dietary changes:  a 29% reduction in the bad cholesterol and a 25% drop in the total cholesterol.

However, although the LDL or bad cholesterol has dropped a lot, the HDL or good cholesterol has dropped by  more: 40%!

This is the typical change when patients cut out dairy fat-the overall ratio of bad  to good cholesterol actually rises.

In addition, the pattern she has now, with a low HDL and high triglycerides is typical of the metabolic syndrome which is recognized as likely to contribute to early  atherosclerosis: so-called “atherogenic dyslipidemia.”

When I plugged both sets of numbers into the ASCVD 10 year risk calculator app (see here) her estimated 10 year risk of heart attack and stroke had actually increased from 7.9% to 8.3%.

Hopefully, this anecdote will reinforce what population studies show:

  • There is NO evidence that dairy fat consumption increases risk of cardiovascular disease (see here)
  • Current recommendations to consume non or low fat dairy (often  accompanied by increase in added sugars) are not supported by scientific studies.

Finally, my patient is another example of an inherited tendency to development of premature atherosclerosis: her diet, exercise, body weight were all optimal and could not be tweaked to lower her risk.

Such patients must deal with the cardiovascular cards they have been dealt. If they have advanced atherosclerosis, as much as they may dislike taking medications, statins are by far the most effective means of reducing their long term risk of heart attack and stroke.