Month: December 2021

Predicting artery clogging with a machine learning model is superior to current risk-based methods

/ William Driscoll / Leave a comment

The likelihood of clogged arteries in patients without symptoms can be far better predicted with a machine learning algorithm based on 12 patient data points, than by the risk scoring systems that doctors currently use, as reported in an article published in the Journal of the American College of Cardiology.

Artery clogging is a progressive disease that ultimately can cause heart attacks, strokes, or dementia. Doctors call the disease atherosclerosis.

Read the free book on “bad” LDL cholesterol, healthy diets, statin safety, and ultrasound artery screening, at the home page: YourArteries.net

Researchers developed a machine learning approach they found to be superior to risk scoring methods for cardiovascular disease that are currently used in the U.S. and Europe. One risk-scoring method used in the U.S., for example, when tested against the data set on which the researchers trained their model, assigned an intermediate or high risk score to only 15% of individuals that in fact had early-stage artery clogging at more than one site.

In contrast, the machine learning algorithm, when validated using a data set of patients separate from the data set on which it was trained, had a much higher success rate in identifying individuals with artery clogging, with an “area under the curve” (a measure of the accuracy of a machine learning model) of 0.83, where 1.00 would be perfect.

The researchers trained their machine learning model using data from 3,515 middle aged individuals, for whom data were available from several sources: blood tests; two-dimensional ultrasound scans of the carotid arteries, the abdominal aorta, and the femoral arteries; and coronary artery calcium scoring.

The top five data points found by the machine learning system to be most predictive of artery clogging were, in order: age, average blood sugar over the past three months (“HbA1c”), the ratio of total cholesterol to “good” HDL cholesterol, leukocyte count (a measure of inflammation), and hemoglobin. Also among the top 10 predictors were “bad” LDL cholesterol and systolic blood pressure (the first number in a blood pressure reading). The effects of LDL cholesterol on artery clogging would also be captured by one of the top three data points, the ratio of total cholesterol (including LDL) to HDL cholesterol.

An editorial accompanying the study highlighted the superiority of the researcher’s machine learning model over risk scoring methods used in the U.S. and Europe. It noted, however, that doctors would find that some patient data elements toward the bottom of the list of 12 predictors are not intuitively related to artery clogging. While those predictors could be unrelated to the success of the model when validated against the separate data set,  the editorial left open the possibility that there could be “strong import” to those predictors that “we may simply not understand.”

The study, available free online, is titled “Machine Learning Improves Cardiovascular Risk Definition for Young, Asymptomatic Individuals.” The accompanying editorial, also available free, is titled “Transforming Data Into Diagnosis: Exercises for a Computer to Perform and a Physician to Interpret.”

Preventing thousands of strokes per year through quick carotid ultrasound screening

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Screening all Americans aged 65 and older with a quick, one-minute carotid ultrasound test could help prevent thousands of strokes per year, says an article published in the Annals of Translational Medicine.

The authors say that a one-minute ultrasound screening test can flag those suspected of having plaque in their carotid arteries causing at least 50% blockage. The carotid arteries carry blood to the brain, and if there is plaque in those arteries and the plaque ruptures, a stroke can result.

Read the free book on “bad” LDL cholesterol, healthy diets, statin safety, and ultrasound artery screening, at the home page: YourArteries.net

For those whose screening test indicates possible substantial blockage, a follow-up “formal” duplex ultrasound test can identify those who indeed have 50% blockage of one or both carotid arteries, the authors say. Those individuals could then protect their arteries and stabilize the plaque, the authors say, by electing either vascular surgery or best medical treatment, with the latter presumably including statin therapy.

A quick carotid scan has been used for many years, the authors say, to screen military retirees at the Madigan Army Medical Center in Tacoma, Washington, and has also been used at New York University.

The authors estimate that their proposed screening and follow-up process would find the estimated 8% of Americans aged 65 and older who, according to their research, have carotid artery blockage of at least 50%. These individuals typically would have had no symptoms, and thus no idea that their arteries were partially blocked. Subsequent treatment could reduce the 5-year risk of stroke for these individuals from 20% if left untreated, to less than 3%, they say.

That would prevent 200,000 strokes and yield one-time Medicare savings of $13 billion from avoided direct medical costs, according to earlier research the article cites, which was led by the same principal investigator.

The authors note that stroke is also the leading long-term Medicare expenditure, “fills one-half of nursing homes,” and “has persisted without reduction for decades,” even though the Centers for Disease Control and Prevention says that 80% of strokes could be prevented.

While Medicare in the U.S. does not cover the cost of carotid screening, “it does reimburse for the further evaluation and management of disease found on screening,” the authors say, “which can cover the nominal monetary outlay of a medical facility to provide the initial screening.”

The authors add that at the time of a quick carotid scan, “there is the option of including an ultrasound scan of the abdominal aorta to discover aortic aneurysms prior to rupture, and of scanning the common femoral artery to identify arteriosclerotic plaques which have a high correlation with coronary artery disease and can be a trigger for a cardiac and metabolic evaluation.”

The study, available online for free, is titled “The quick carotid scan for prevention of strokes due to carotid artery disease.”

Artery clogging can progress “significantly” in middle age

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Artery clogging progressed “significantly” in 41% of a group of apparently healthy middle-aged men and women over a three-year period, found a study published in the Journal of the American College of Cardiology.

The authors note that the progression of artery clogging is linked to heart attacks and strokes, citing earlier research.

Even in those designated as “low risk,” progression of artery clogging was found in 36% of study participants.

Read the free book on “bad” LDL cholesterol, healthy diets, statin safety, and ultrasound artery screening, at the home page: YourArteries.net

Progression was measured both as an increase in the number of arterial plaque lesions, and as an increase in the total volume of arterial plaque.

Progression was detected more frequently in peripheral arteries, as measured by 2-dimensional and 3-dimensional ultrasound tests, than in the coronary arteries, as measured by the coronary artery calcium score.

The authors found that higher levels of cholesterol in the blood contributed to progression of artery clogging, and noted this is the risk factor that is the most easily modified.

An editorial comment published with the study noted that artery clogging at more than one site has been found to be “essentially ubiquitous” in those age 60 years and older, with over 90% of men and women of that age group having arterial plaque in at least one site.

The study, available free online, is titled “Short-term progression of multi-territorial subclinical atherosclerosis.” Atherosclerosis is the medical term for artery-clogging, and subclinical means early-stage. The editorial comment, also free online, is titled “Evaluating multi-site atherosclerosis and its progression: ready for prime time?”

Most healthy people with LDL above 130 mg/dL will have some artery clogging by their mid-40s

/ William Driscoll / Leave a comment

Half of middle-aged people without risk factors for cardiovascular disease were found to have plaque in their arteries, in a study published in the Journal of the American College of Cardiology. The men and women in the study, nearly all in their 40s, each had a level of “bad” LDL cholesterol lower than 160, and none of the major risk factors of smoking, family history, high blood pressure or diabetes.

As plaque deposits in arteries grow larger, they can ultimately cause a heart attack, stroke, or dementia.

Read the free book on “bad” LDL cholesterol, healthy diets, statin safety, and ultrasound artery screening, at the home page: YourArteries.net

Of the 1,779 healthy subjects, 30% had plaque in their arteries supplying blood to the legs, 23% in their carotid arteries supplying blood to the brain, and 17% in their abdominal aorta, while 11% had calcified plaque in their coronary arteries supplying oxygenated blood to the heart. Researchers tested the first three locations using ultrasound, and the last using a coronary artery calcium test. They found that 23% had plaque in one location, 21% had plaque in two or three locations, and 6% had plaque in four or more locations.

While this study evaluated subjects with no major risk factors, the researchers also noted their previous study showing that in a group of middle-aged men and women at “low” risk of cardiovascular disease, 60% had arterial plaque in at least one location, and 41% had plaque in two or more locations.

In an editorial comment on the study, the journal’s editors suggest that arterial imaging at an early stage could be used to guide treatment decisions that could help prevent cardiovascular disease.

The study, which is available free online, is “Normal LDL-cholesterol levels are associated with subclinical atherosclerosis in the absence of risk factors.” Atherosclerosis is the medical term for artery clogging. The editorial comment, also available free, is titled “Primary prevention of atherosclerosis: time to take a selfie?”

Early-stage artery clogging slows down your brain; statins can help

/ William Driscoll / Leave a comment

Artery clogging not only causes heart attacks and strokes, but also slows down your brain, according to a study published in the Journal of the American College of Cardiology.

Fortunately, you can get tested for artery clogging, even without a doctor’s order, and if your arteries are getting clogged, a statin drug can slow, stop, or even reverse the process.

Read the free book on “bad” LDL cholesterol, healthy diets, statin safety, and ultrasound artery screening, at the home page: YourArteries.net

The study’s authors evaluated participants who had early-stage plaque in their carotid arteries, which carry blood to the brain. These individuals were found to have “reduced brain metabolism” relative to participants with unclogged arteries. Areas of the brain showing reduced metabolism included areas “known to be affected in dementia.”

The authors pointed to “the need to control cardiovascular risk factors early in life in order to reduce the brain’s midlife vulnerability to future cognitive dysfunction.”

The good news for now is that if you’re middle-aged or older you can obtain, with or without a doctor’s order, a carotid artery ultrasound test to identify the presence or extent of clogging in your carotid arteries.

And if that test shows that the carotid arteries are clogged, a preventive cardiologist can prescribe statins at a dose high enough to aggressively lower your level of “bad” LDL cholesterol, which is a major component of the plaques that clog arteries. A daily statin pill at the right dose can not only protect the brain but can also stabilize the arterial plaques throughout the body, or even shrink existing plaques, lowering the chance of a heart attack or stroke.

The study, available free online, is titled “Subclinical Atherosclerosis and Brain Metabolism in Middle-Aged Individuals: The PESA Study.” Atherosclerosis is the medical term for artery clogging.

Cardiologists propose testing people for clogged arteries

/ William Driscoll / Leave a comment

By William L. Driscoll

Five cardiologists have proposed that doctors test people for clogged arteries, and offer those found to have the disease a statin prescription, to prevent heart attacks and strokes.

Their proposal, which would overhaul current medical practice, was published as a state-of-the-art review by the Journal of the American College of Cardiology.

Current medical practice to prevent heart attacks and strokes among those without symptoms is based on a risk-scoring system to predict those most likely to have a heart attack or stroke.

The cardiologists propose instead to “treat the disease rather than the likelihood of disease,” by directly testing for clogged arteries.

Artery clogging that has not yet caused symptoms can be detected using any of four “readily available” imaging tests, they say.

One of those tests, a carotid artery ultrasound, is available in the U.S. without a doctor’s order, from Life Line Screening. The test is like the ultrasound test for pregnant women, except that it scans the neck instead of the belly.

Read the free book on “bad” LDL cholesterol, healthy diets, statin safety, and ultrasound artery screening, at the home page: YourArteries.net

The other tests require a doctor’s order. One is an ultrasound scan of the infrarenal
aorta, a major artery below the kidneys. The others are two versions of a
coronary artery calcium test, which assesses the level of calcium in the coronary
arteries that serve the heart muscle, using a type of X-ray called computed
tomography. One version of that test uses a contrast agent and the other does
not.

The other three tests require a doctor’s order. One is an ultrasound scan of the infrarenal aorta, a major artery below the kidneys. The others are two versions of a coronary artery calcium test, which assesses the level of calcium in the coronary arteries that serve the heart muscle, using a type of X-ray called computed tomography. One version of that test uses a contrast agent and the other does not.

The cardiologists present a carefully reasoned case for their proposal. First, they say the majority of heart attacks occur due to the rupture of plaque on an artery wall, where the plaque was partially clogging the artery. They add that plaque progression is “a necessary and modifiable step” between early-stage artery clogging and a heart attack. For patients for whom screening finds early-stage artery clogging, “intensive” lipid-lowering therapy would begin “to halt plaque progression” to prevent a heart attack.

The cardiologists did not suggest how to determine which patients are appropriate for noninvasive screening that checks for artery clogging. As noted above, individuals who have reached middle age can get themselves checked for artery clogging, without a doctor’s order.

The article—which uses the medical term “atherosclerosis” to refer to artery clogging—is titled “From Subclinical Atherosclerosis to Plaque Progression and Acute Coronary Events: JACC State-of-the-Art Review.” It is available free online.

Statin therapy is usually well tolerated and safe, says the American College of Cardiology

/ William Driscoll / Leave a comment

By William L. Driscoll

Side effects from statins are “infrequent or rare” in clinical trials, and statin therapy is “usually well tolerated and safe,” according to the guideline on cholesterol management from the American College of Cardiology and the American Heart Association.

Statins are used to lower a patient’s LDL (“bad”) cholesterol, and thereby reduce the formation of plaques in the arteries, which can lead to heart attack, stroke, or dementia caused by mini-strokes.

The most frequent statin-associated side effects are muscle symptoms, usually muscle pain, reported in 5% to 20% of patients, the guideline says. In patients with muscle symptoms, a doctor should conduct a “thorough assessment” of symptoms, and conduct an evaluation for non-statin causes and predisposing factors.

Read the free book on “bad” LDL cholesterol, healthy diets, statin safety, and ultrasound artery screening, at the home page: YourArteries.net

Statins “modestly” increase the risk of diabetes among those who have risk factors for diabetes, “but this should not be cause for discontinuation,” the guideline says.

Liver problems are infrequent, while rhabdomyolysis and other side effects are rare, and there is “no definite association” with cancer. The guideline’s Table 11 provides more detail.

Among those who experience side effects, the “large majority“ are able to tolerate an alternative statin or an alternative regimen, such as a reduced dose, or a reduced dose in combination with a non-statin drug, the guideline says.

The guideline recommends a doctor-patient risk discussion before starting statin therapy, to weigh the potential for reducing the risk of cardiovascular disease against the potential for statin-associated side effects and statin–drug interactions. In this discussion, the doctor should emphasize that “side effects can be addressed successfully.”

A doctor prescribing a statin should assess the patient’s “appropriate safety indicators” 4 to 12 weeks after starting a statin or adjusting the dose. The assessment should also review the patient’s adherence to any recommended lifestyle changes, and the patient’s LDL level. Assessments should be repeated every 3 to 12 months, based on the need to assess adherence or safety.

The “Guideline on the Management of Blood Cholesterol” is available free online from the Journal of the American College of Cardiology. It was prepared by the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines.

High blood pressure above 130/80 is a good reason to get checked for artery clogging

/ William Driscoll / Leave a comment

By William L. Driscoll

Even a mild form of high blood pressure—where the first number is from 130-139, or the second number is from 80-89—is a strong predictor of artery clogging, as reported in a scientific journal article in the American Journal of Hypertension.[1] At blood pressure readings above those levels, researchers found that the prevalence and burden of artery clogging increased.

Overall, the contribution of high blood pressure to artery clogging has been “intensively studied” and is “well understood,” says a scientific journal article published in the journal ­­­­­Cells.[2]

So a doctor could tell someone with elevated blood pressure that their arteries may be getting clogged, that artery clogging increases their risk of a heart attack or stroke, and that there are good options to screen for artery clogging, and to treat it, if found.

Unfortunately, many doctors don’t say that. So if you or someone you know has been diagnosed with high blood pressure, here’s what you should know.

Read the free book on “bad” LDL cholesterol, healthy diets, statin safety, and ultrasound artery screening, at the home page: YourArteries.net

Screening can tell anyone whether they have artery clogging that has reached a concerning level. If so, they may then find a preventive cardiologist, who can help them slow or stop the progression of artery clogging through aggressive lowering of LDL (bad) cholesterol.

Ultrasound screening of the carotid arteries can indicate the extent of artery clogging throughout the body. The ultrasound test is just like the one used for pregnant women, but is performed on the neck, where the carotid arteries are, instead of the belly.

Regrettably, carotid ultrasound screening is not yet routinely available to patients at their doctor’s office. Some doctors and traditional cardiologists may be willing to order a carotid ultrasound test on the basis of a high blood pressure reading, particularly if that reading is fairly high.

Alternatively, people over 50 can obtain such screening from the company Life Line Screening, which offers a rapid form of carotid artery ultrasound screening.

The results of such rapid testing may be helpful in securing an appointment with a preventive cardiologist. Even if the results indicate carotid artery blockage of less than 50%, a preventive cardiologist may offer an appointment, because artery clogging can advance rapidly,[3] and preventive cardiologists aim to prevent further artery clogging. During an appointment, a preventive cardiologist might decide to order a “gold standard” carotid artery screening test, which provides more information but takes a bit longer, and therefore costs more.

In the future, carotid artery ultrasound tests may be available from your regular doctor, as part of a routine physical, using a low-cost handheld ultrasound device made by GE, Philips, or Butterfly Network.

[1] https://academic.oup.com/ajh/article/33/1/92/5552456

[2] https://www.mdpi.com/2073-4409/9/1/50

[3] https://www.jacc.org/doi/10.1016/j.jacc.2020.02.026

Preventive cardiologists aim for an LDL cholesterol level as low as 40 in appropriate patients

/ William Driscoll / Leave a comment

By William L. Driscoll

Especially if you have a family history of heart attacks and strokes, like I do, you may be familiar with LDL cholesterol. LDL is the bad kind of cholesterol that contributes to artery-clogging plaque, which can lead to a heart attack or stroke, or to mini-strokes that cause dementia.

Any LDL-cholesterol level lower than 100 is widely considered to be “optimal,” according to a standard that dates back at least to 2005.[1] Yet preventive cardiologists aim for much lower levels in appropriate patients.

Read the free book on “bad” LDL cholesterol, healthy diets, statin safety, and ultrasound artery screening, at the home page: YourArteries.net

One preventive cardiologist, Dr. Roger Blumenthal, recently helped me lower my LDL number to 40, by prescribing a moderately high-dose statin drug.

Because my regular doctor had told me that any LDL level below 100 is optimal, I asked my cardiologist whether my new LDL level of 40, after three months on the statin, might be too low.

He said an LDL level of 40 “is ideal and levels in that range are more likely to result in modest reversal of some of the plaque buildup, as well as stabilization of the plaques throughout your body.”

An LDL level of 40 “should be considered to be physiologically ‘normal,’” said the president of the American Society for Preventive Cardiology, Dr. Peter Toth, in a journal article published in 2020.[2] The article cited research showing that the risk of coronary heart disease increases exponentially at increasing LDL levels above 40.

[1] https://www.nhlbi.nih.gov/files/docs/public/heart/wyntk.pdf

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8315455/

Adverse effects of statins are rare, says the European Society of Cardiology

/ William Driscoll / Leave a comment

By William L. Driscoll

In deciding on a statin prescription to slow the progression of artery-clogging (atherosclerosis), a patient and doctor weigh the benefits of treatment against the potential adverse side effects of the statin.

Adverse effects of statin therapy are rare, said the European Society of Cardiology (ESC), in its 2021 guidelines on cardiovascular disease prevention.

Because many patients will want to know more than that basic information, here are some specifics.

Read the free book on “bad” LDL cholesterol, healthy diets, statin safety, and ultrasound artery screening, at the home page: YourArteries.net

Myopathy and rhabdomyolysis

The most frequent adverse effect of statin therapy is myopathy, a muscle disorder, the ESC guidelines say “but this is rare.”[1]

The most serious adverse effect, rhabdomyolysis is “extremely rare,” say the ESC guidelines.

Muscle weakness is the primary symptom of myopathy, according to the U.S. National Institutes of Health.[2]

The Mayo Clinic notes that rhabdomyolysis or milder forms of muscle inflammation from statins can be diagnosed with a blood test measuring levels of the enzyme creatinine kinase. The Mayo Clinic advises that “if you notice moderate or severe muscle aches after starting to take a statin, contact your doctor.”[3]

Increased risk of diabetes

Increased blood sugar levels that increase the risk of diabetes can occur after statin treatment begins and are “dose dependent, in part linked to slight weight gain,” say the ESC guidelines, adding that the benefits of statins “outweigh the risks for the majority of patients.”

In medical journal articles, the issue of statin side effects is often discussed in terms of patients who do not tolerate statins.

The ESC’s full summary of adverse effects from statin therapy are available its guidelines, under section 4.6.3.1.3.1, from the link in the footnotes below.

To learn more about maintaining healthy arteries, see YourArteries.net.

[1] European Society of Cardiology, “2021 ESC Guidelines on cardiovascular disease prevention in clinical practice” (see section 4.6.3.1.3.1.):

https://academic.oup.com/eurheartj/article/42/34/3227/6358713 OR https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/2021-ESC-Guidelines-on-cardiovascular-disease-prevention-in-clinical-practice

[2] https://www.ninds.nih.gov/Disorders/All-Disorders/Myopathy-Information-Page

[3] https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/expert-answers/rhabdomyolysis/faq-20057817