The Presidential Coronary Calcium Score and the Power of Zero

 

“Maybe I’ll win

Saved by zero”

The Fixx, 1983

 

Since the 1990’s, the U.S. Presidents and the Presidential candidates have undergone coronary calcium scores. What can we learn from their results? Let’s look at two examples. Let’s call them the Clintons. Hillary Clinton reportedly had a coronary calcium score of 0. As far as we know, she has not had any heart disease. Bill Clinton’s coronary calcium score was over 1000. He subsequently required open heart bypass surgery. Can you guess the coronary calcium scores of Presidents George Bush, Barack Obama and Donald Trump? What is the coronary calcium score and can you be “saved by zero”?

 

To understand coronary calcium, we must understand the process of atherosclerosis in the heart arteries. In susceptible individuals, plaque formation starts at an early age, the 20’s and 30’s. The initial plaque in the heart arteries is made of cholesterol, what is called “soft” plaque or “fatty” plaque. If we did a CT scan at this stage, no calcium would be detected. Over time, plaque progression continues and by the age of 50 to 60, calcium is deposited in the plaque. The plaque is now considered “hard” plaque. At this stage, a CT scan would detect calcium in the artery. Coronary calcium therefore detects the presence of plaque in the heart arteries. It does not tell us if the plaque is limited to the artery wall or if the plaque is causing significant blockage to the blood flow (obstruction can be determined with a stress test or a heart catheterization).  

 

What is the coronary calcium score and how is it used? Coronary calcium score is obtained with a CT scan. There is no fasting, no preparation, no intravenous and no dye used. The person goes under the CT scanner, holds their breath for about one minute, the scan is taken and done. What do the results mean? For people between the ages of 40 and 75 without established heart artery disease, the score is used as follows. A score greater than 100 represents extensive plaque and an increased risk for future cardiac events (heart attack, blocked heart artery, stroke, cardiac death). In this case a statin (and perhaps aspirin 81 mg once per day) is recommended. A score between 1 and 99 is intermediate. Even a low calcium score (between 1 and 10) is associated with a two times greater risk for cardiac events compared to score of zero. In this population, a statin is recommended if high risk characteristics are present (age over 55, family history of premature heart disease, persistently elevated LDL cholesterol or triglycerides, evidence for inflammation or elevated lipoprotein a in the blood). 

 

What does a coronary calcium score of zero represent? There are two clinical possibilities. One is that there is no heart artery plaque. The other scenario is that there is soft or fatty plaque present, which has not yet calcified. Most studies have found that among patients with coronary calcium of zero, there is a very low likelihood of blockage in the heart arteries and a low risk for heart events (heart attack, stroke, death). However, one study looked at 10,000 people and found that 45% of them had a coronary score of zero. Among those with zero scores, 1.8% still had at least one artery blocked 50% or greater. The prognostic value of a zero score was less for those under the age of 45 (they likely had not had enough time for the plaque to calcify). In general, a coronary calcium score of zero is a good prognostic sign. How long does that prognostic value last? What is the warranty period of a calcium score of zero? A study showed that about 15% of people with initial calcium score of zero progressed to a score over 10 in about 5 to 8 years. In the study it was rare to progress to a calcium score over 100. Diabetic patients, active smokers and those with strong family history progressed more quickly. Based on these data, it is recommended that statin therapy be withheld for a patient with a calcium score of zero, unless they have diabetes, are smoking or there is a family history of premature heart disease. How often should the calcium score be repeated to reassess risk? For patients with a coronary calcium score of zero, repeating the study is recommended in 3 to 5 years. For patients with an elevated coronary calcium score who are already on statin, it is not recommended to have a follow up study. The reason is that the calcium score may go up on statin treatment. If the score goes up, we don’t know if there has been further plaque progression or increasing calcium in existing plaque- a sign of healing.

 

Using the coronary calcium can help predict the risk for future heart events in patients between 40 and 75 years old who have not yet had a cardiac issue (primary prevention). If you are like Bill and your coronary calcium score is greater than zero, initiating lifestyle changes and starting a statin can reduce the risk for a heart event in the future. If you are lucky like Hillary and your coronary calcium score is zero, the risk for future events is low. However, it is not a “get out jail free” card nor are you “saved by zero”. If coronary calcium score is zero and LDL cholesterol is high, then lifestyle changes should be incorporated even if starting a statin may be avoided. Vigilance is necessary with follow up lipid panels and repeat coronary calcium testing in 3 to 5 years. 

POTS or Why Am I Dizzy When I Stand Up?

 

When you think about, we shouldn’t be able to stand upright. Our ancient ancestors, floating around in the sea, used the water for everything; hydration, nutrition and support. The water buoyed them, there was no need for a spine or other elaborate bony structures. To leave the water and especially to walk upright on two legs, certain adaptations were needed. Skeletal features that evolved over time included a spine, hip bones, thigh bones and the muscles needed to keep the body upright and erect. Circulatory adaptations were needed as well. When we are upright, the heart has to pump blood against gravity to keep blood flowing to the brain. Blood pressure to the brain must be maintained otherwise when we stand up, the blood pressure would drop, the blood flow to the brain would decrease and we would pass out. How does the circulation respond to standing and why don’t we routinely pass out?

 

The mechanism that evolved to keep us upright is a blood pressure feedback loop that involves the heart, the brain and the blood vessels. On standing, blood pools in the veins in the legs. This causes a transient decrease in blood pressure. This drop in blood pressure is recognized by a sensor in the carotid artery (the carotid artery is the main artery supplying blood to the brain, the sensor is located in the carotid sinus, just outside of the skull). When the carotid sinus senses a lower blood pressure, it fires nerves which activate the sympathetic system. The sympathetic system constricts blood vessels, increases the heart rate and increases the amount of blood pumped by the heart ultimately restoring normal blood pressure to the brain and preventing passing out.

 

This mechanism is very effective at maintaining blood pressure. However, there are circumstances where the mechanism is overwhelmed causing dizziness or passing out. Instances include prolonged standing in a hot environment (think of a soldier standing for a long time in the hot sun), dehydration, or deconditioning from staying in bed for a long time. As we age, the mechanism isn’t as fast and we can have dizziness on rising quickly from a sitting or lying down position. If the mechanism isn’t working, it leads to passing out on standing, a condition called orthostatic hypotension (from the Greek ortho- straight and statikos- causing to stand; caused by standing erect; hypotension- low blood pressure). Orthostatic hypotension is defined as a drop in systolic blood pressure of 20 mmHg or more within three minutes of standing. It is a significant medical problem whose incidence rises after age 65. It occurs in 6% of elderly people in the community and up to 50% of people in nursing homes. Orthostatic hypotension puts patients at risk for falls, as well as cardiac disease. Orthostatic hypotension occurs in patients with degenerative diseases of the autonomic nervous system (for example, Parkinson’s disease). It also occurs due to an impaired autonomic nervous system (for example, diabetes). Orthostatic hypotension can be diagnosed in the office or at the hospital bedside by checking blood pressure lying down and standing up. The formal way to diagnose it is with a tilt table test (strapping a patient to an upright table and checking blood pressure frequently). 

 

There are multiple ways to treat orthostatic hypotension. In milder forms, patients recognize that they are about to pass out and can sit or lay down to avoid falling. For more significant cases, the first step is to stop medications that can lower the blood pressure or exaggerate orthostatic symptoms. Medications to avoid include diuretics, most blood pressure meds, prostate medications (ex, Flomax or tamsulosin), antiparkinson agents and antidepressants. Other measures include increasing blood volume by keeping hydrated, ingesting salt tablets, or using a medication (fludrocortisone) which promotes salt retention. Pooling of blood in the veins of the lower legs can be decreased by using compression stockings. Lastly, medications that stimulate the sympathetic nervous system (such as midodrine or droxidopa, Northera) can be used. 

 

POTS (postural orthostatic tachycardia syndrome) is the most common form of orthostatic intolerance in young people. It usual affects young, pre-menopausal women with as many as 500,000 cases in the US. It is defined as an increase in the heart rate of 30 beats per minute or more within 10 minutes of standing, but without a decrease in blood pressure. The typical patient is a 30-year-old woman with a heart rate increment of 40 beats per min or more. Cardiovascular deconditioning is common. Therefore, the key to treatment is exercise. The exercise regimen should avoid the upright position (swimming or recumbent bike can be prescribed) until fitness improves. Liberal intake of fluids and salt, compression stockings and sleeping with the head of the bed greater than 30 degrees are other methods. Medications can be used in severe cases and include the same agents used for orthostatic hypotension. 

 

Whether you are young or old, if you have dizziness on rising there are measures you can take to avoid symptoms. If you have more severe symptoms or are passing out on standing, see your doctor to work through how to keep yourself upright. 

How Sweet It Is!

 

Ralph: (growling) Where's my morning coffee?

Alice: Here you go Ralph

Ralph: (sipping) That tastes terrible!

Alice: We ran out of sugar

Ralph: One of these days, Alice. One of these days. 

Alice: Try this new artificial sweetener

Ralph (sipping) How sweet it is!

 

If you are of a certain age, you can identify these characters from the 1950’s television show "The Honeymooners" and you’ll recognize the Ralph Kramden/Jackie Gleason catchphrase, "How sweet it is!". So how sweet are artificial sweeteners? Depending on the agent, artificial sweeteners are 200 to 600 times sweeter than sugar. However, are they healthier than sugar? Are there any heart issues with artificial sweeteners?

 

Sugar seems to be the new bad guy on the block, not without reason. Everyone likes a sugary snack every now and then, but can it be limited to just one snack? Sugar triggers a reaction in our brain and makes us crave more. Sugar begets sugar. So, instead of stopping at one serving, more sugar is desired and before you know it, the whole candy bar is gone. All that sugar consumption adds empty calories, resulting in obesity, diabetes and heart disease. Even natural sweeteners, such as honey or molasses are a form of added sugar and add calories to the diet. To counteract the health effects of sugar, artificial sweeteners were developed and have been available for decades. Artificial sweeteners taste sweet like sugar but have no or few calories. They allow people to enjoy the sweetness of foods and drinks but without excess calories.  In this way, artificial sweeteners can help with weight loss. US and European health agencies have deemed artificial sweeteners safe in limited amounts and extensive research has not shown a higher risk of cancer. It had been felt that these sugar substitutes do not cause serious health problems. Until now.

 

Recent research on artificially sweetened beverages has shown a link to heart disease. A French study started in 2009 and including 104,000 participants found that people who drank 6 ounces or more per day of artificially sweetened beverages had a higher risk for cardiovascular disease. Artificial sweetened beverages included drinks that contained aspartame (also used in NutraSweet, Equal) and sucralose (found in Splenda). Another study of 9000 participants followed for 10 years showed that those who drank greater than two liters per week (about 10 ounces per day) of an artificially sweetened beverage had an increased risk for atrial fibrillation. One last study followed 2,888 participants and found artificially sweetened drinks to be associated with a higher risk of stroke and dementia. So, these beverages may not be a healthy substitute for sugary soft drinks.

 

The data on two artificial sweeteners, both from the sugar alcohol category, seems especially troubling. Erythritol is a no calorie sugar substitute used in many products including protein bars, yogurt, cookies and ice cream. It occurs naturally in melons and grapes. It is also the primary sweetener in the low carbohydrate high fat keto diet. A 2023 study of 1100 people found that high levels of erythritol in the blood was associated with an increased risk of heart attack, stroke and death. A more recent study may explain why. Twenty healthy volunteers were given drinks sweetened with a typical amount of erythritol or a drink with sugar. When given erythritol, the blood platelets were activated putting people at risk for blood clotting, heart attack or stroke. The same platelet effect was not seen when consuming a sugar drink. Another sugar alcohol artificial sweetener, xylitol, has similar data. Xylitol is found naturally in fruit and vegetables. It is also used to sweeten gum and toothpaste. In a study of 3000 people in the US and Europe, those with the highest level of xylitol in the blood were more likely to have heart or blood vessel problems. Another study followed 1100 people for three years. Xylitol was associated with major adverse cardiac events and was shown to activate platelets, similar to erythritol. 

 

As daunting as this data is, experts have not declared any artificial sweetener a cardiac risk. However, more and better research is needed on these agents, especially the potential cardiovascular effects. Before you declare “How sweet it is!” and consume artificial sweeteners with impunity, keep an eye out for future research on the safety of these agents. For now, using them in small, limited quantities seems to be safe. 

 

The Siesta

The Siesta (or La Meridienne in French) is a famous painting by the artist Vincent Van Gogh. It depicts a siesta and symbolizes life in rural France in the late 1880’s. Siesta is a Spanish word meaning a short nap, usually taken in the afternoon, after lunch. In warm weather climates workers who do physical labor need to take a break to avoid the hottest part of the day. Siestas are common in Mediterranean countries, the Middle East, China, Latin America and the Philippines. Siestas are both practical and cultural. There are studies from Greece showing that naps are associated with a lower risk for heart attack. What is the data on siestas? How does day time napping affect cardiac health?

 

The health data on siestas is quite variable, showing some good and some bad effects. In a study from 2019, taking a daytime nap was associated with lower blood pressure. In those that nap, the blood pressure was 5 mmHg lower than in those that didn’t nap. Usually when something lowers blood pressure there is concomitant lowering of cardiac risk.  That doesn’t seem to be the case with napping. A comprehensive review of relevant studies showed that daytime napping over 60 minutes was associated with an increased risk for cardiac disease and mortality.  Another study followed 116, 000 people for 8 years and found that napping was associated with increased for major cardiac events and death in those that slept on average more than six hours per night. No increased risk was found in people who slept less than 6 hours per night. It was felt that naps compensated for lack of sleep for people who didn’t get enough sleep at night. The most recent study found some disturbing trends. The trial studied 476,000 people determining that 56% never or rarely took a nap, 38% sometimes napped and 5% usually took a daytime nap. Compared to people who never or rarely napped, frequent daytime napping increased the risk for atrial fibrillation and for dementia. This is the first time this association was made regarding the siesta. Why does napping lead to atrial fibrillation? One hypothesis is that napping indicates inadequate nighttime sleep from undiagnosed sleep apnea, a condition well known to cause atrial fibrillation. In addition, atrial fibrillation is a risk for dementia. 

 

It appears that frequent daytime napping can lead to dementia. What is the optimal amount of sleep to avoid dementia? The largest sleep study ever conducted just finished and concluded that 7 hours of sleep per night was the right amount for reasoning, verbal skills and overall cognitive thinking.  Sleeping more or less than that could lead to cognitive decline and dementia. What other new data has emerged regarding dementia? Eating processed red meat and sugar have been associated with dementia. Processed red meat (including bacon, hot dogs, sausages, salami, cold cuts) has been tied to an increased risk of cancer, heart disease and diabetes. A new study that tracked 100,000 people over four decades showed that eating two servings of red meat each week increased the risk for dementia by 14% and was associated with worse memory and thinking skills. The study also showed that replacing red meat with nuts, beans or tofu lowered the risk for cognitive decline by 23%. Processed red meat may affect the brain because of harmful chemicals such as nitrites and the increased sodium content can lead to high blood pressure. The study only found an association but did not prove cause and effect. So, we don’t know if red meat itself causes dementia or if people who avoid red meat are generally more health conscious. Unprocessed red meat, such as ground beef or steak, was not linked to dementia in the trial. In other news, on World Brain Day (July 22 2024), the German Society of Neurology warned that too much sugar can harm the brain.  High blood sugar levels can damage blood vessels, causing plaque, decreasing blood flow and causing vascular dementia. In addition, sugar directly affects the nerve cells, impairing cognition. What should be eaten instead? Try to eat whole fresh foods (fruits, vegetables, fish, nuts, beans) and the less processed, the better. Whole fresh foods bring protein, fiber, nutrients, minerals and vitamins the brain promoting a healthier body and longer lifespan.

 

Last month we found out that to decrease your risk for dementia you should take your blood pressure medications, go to the shore, plop down on a beach chair and watch the waves roll in. This month we learn that, to further lower your risk for dementia, try not to nap in that beach chair. In addition, skip the hot dog, ice cream and cotton candy on the boardwalk. It is hard to do, but it may be well worth it. 

Beach Blanket Blood Pressure

 

It’s July! Summer time! Time to vacation and unwind. Head to your favorite beach, plop down on your beach chair and watch the waves role in. You can feel yourself relaxing, calming down. You can actually feel your blood pressure (BP) dropping. Does the presence of water really lower BP? Researchers actually did this study. They found that viewing water in an outdoor setting (for example a lake) reliably lowered BP compared to looking at grass field. Aside from water watching, what else is new in the world of hypertension (high blood pressure)?

 

Before diving into new data, some basics about hypertension. Despite knowing about high BP for more than 100 years and despite the fact that nearly 50% of the population has hypertension, we still do not know what causes it. What is the definition of hypertension? Hypertension is diagnosed as a BP greater than 130/80 on multiple occasions over several weeks. What is the ideal BP? 115/75. Several studies have shown that treating BP to under 120 mmHg improved outcomes versus treating to a BP under 140 mmHg. The under 120 mmHg group had fewer heart events, lower mortality and less cognitive decline. It is important to understand that the BP is not one single, stable number. Rather BP goes up and down, like waves on the ocean, with activity, time of day, and medications among other factors. The goal is to have nice, calm undulating waves of BP, not tidal waves with extreme highs and very low lows. Also, the goal is to have the BP average under 140 mmHg, or more ideally, under 120 mmHg. Hypertension is treated with lifestyle modifications and medications. Lifestyle changes include exercise, weight loss, smoking cessation and following a DASH diet. Sodium reduction (a low salt diet) is also important for treatment. First line medications for hypertension fall into three classes of drugs: diuretics (hydrocholorothiazide, chlorthalidone), calcium channel blockers (amlodipine) and angiotension converting enzyme inhibitors (lisinopril, ramipril) or angiotension receptor blockers (losartan, olmesartan). Reducing BP with medications reduces the risk of dying, reduces stroke by 35-40%, reduces heart attack by 20-25%, reduces heart failure by more than 50% and decreases the risk for dementia and cognitive impairment. 

 

Of the three classes of medications, which one is best? A recent study followed 33,000 patients for 23 years looking at the three types of medications and assessing outcomes. The researchers found no difference among the three classes in their BP lowering efficacy and no difference in cardiovascular mortality or stroke. 

 

In this era of BP medications is a low salt diet still recommended? High sodium (salt) intake has long been associated with hypertension. BP clearly goes up with sodium intake of 2 grams per day (2 grams of sodium is about 88% of a teaspoon of table salt). It is estimated that Americans eat on average 3.4 grams of salt per day. The optimal goal for salt intake is about 1.5 grams per day. Lowering sodium intake can reduce BP by 5 to 6 mmHg. Does this effect persist if patients are already on BP meds? A recent trial studied 213 people on BP medications. They were given a high sodium diet for one week, then a low sodium diet the second week and their BPs were tracked. BP was 8 mmHg higher on the high sodium diet. The low sodium diet consistently lowered BP, on top of the presence of medication. The conclusion, “Don’t underestimate the power of salt”.

 

Elevated systolic BP is linked to mild cognitive impairment and dementia. Hypertension may cause dementia by direct and indirect methods. A direct mechanism is the known risk between hypertension and stroke. Multiple small strokes due to elevated BP can cause dementia over time. An indirect mechanism is atrial fibrillation. Hypertension is associated with atrial fibrillation, which in turn can cause blood clots which break off from the heart and travel to the brain. It has long been felt, but not proven, that BP lowering reduced the risk for dementia. However, new data is beginning to emerge. Now we have learned that just by taking medication, dementia can be avoided. A study from Italy followed 215,000 patients for seven years. The patients were starting BP medications for the first time. It was found that the patients who were more adherent to their BP meds (more likely to take their meds) had lower odds of going on to dementia. Another recent study was the first definitive trial to show that BP reduction lowered the risk for dementia. The study looked at 34,000 patients age 40 and older. In patients with intensive BP reduction (goal < 130/80), dementia was lowered by 15% and cognitive impairment improved as well. These results are exciting because now there is a potential tool to prevent dementia. 

 

In order to control your blood pressure and reduce your risk for dementia this summer, don’t forget to take your medications regularly, follow a low salt diet and head out to the beach.

 

 

 

Fun With Stress (How to Read the Exercise Stress Test Report)

 

If you are having heart symptoms (chest pain or shortness of breath, especially with exertion), your doctor may order an exercise stress test to see if the symptoms are related to underlying heart disease. Approximately 10 million exercise stress tests are done in the US each year. What is an exercise stress test? What is it used for? What information does it provide and how can that information be used?

 

With the exercise stress test, the patient is attached to an EKG machine and a blood pressure cuff is placed on the arm.  The patient then walks on the treadmill according to protocol. The most commonly used protocol is the Bruce protocol, developed by Dr Robert Bruce and in use since around 1963. The Bruce protocol starts at 1.7 mph and a 10% incline. Every three minutes, the treadmill goes higher and faster. Stage 2 of the Bruce protocol is 2.5 mph with a 12% incline, Stage 3 is 3.4 mph, 14%, and so on. During the stress test, the patient is monitored for symptoms (chest pain, shortness of breath), the blood pressure is checked every stage and an EKG is done at the end of each stage. The test is terminated if the patient has chest pain, can’t exercise further, develops changes on the EKG (ST segment depression), develops a significant arrhythmia or the blood pressure goes too high. 

 

Let’s look at a typical report (shown above). Under “Exercise Test Summary” is the raw data; stage, time in stage, treadmill speed (mph), grade (%), heart rate (HR) and blood pressure (BP). This patient exercised for 7 minutes 23 seconds of a Bruce protocol, 3 minutes each in stages 1 and 2 and 1 minute 23 seconds in stage 3. The person achieved a work load of 10.4 METs. The metabolic equivalent of task (MET) is an estimation of the person’s exercise capacity, based on how many minutes of the Bruce protocol is achieved. The resting heart rate was 81 BPM and rose to 166 BPM or 92% of the predicated maximal heart rate. The heart rate should increase as the work load increases (work load increases with each progressive stage). Before the test, each person’s maximal heart rate is calculated. During the test, exercise continues until the patient achieves at least 85% of their predicated maximal heart rate. A rough estimate of the maximal heart rate is:

            Max HR = 220 – age

More precise estimates are used based on age and sex:

            Men:                Max HR = 208- (0.7 x age)

            Women:          Max HR= 206 – (0.88 x age)

The blood pressure was 128/80 mmHg at rest and 166/80 mmHg at peak exercise. The systolic blood pressure increases linearly with each stage and returns to baseline or, more often, below the baseline in the recovery period. The average increase in systolic blood pressure with exercise is about 30 to 40 mmHg. A blood pressure over 200 to 210 mmHg represents exercise induced hypertension. Diastolic blood pressure usually stays about the same during exercise. This test was terminated due to fatigue and the person had no chest pain. There were occasional PVCs (premature ventricular contractions, extra beats from the lower chamber of the heart). There were some ST segment changes, 0.5-1.0 mm horizontal ST segment depression. ST segment changes of more than 1.0 mm are considered abnormal.  Horizontal ST segment depression is worse than upsloping depression. Downsloping ST segment depression is worse than horizontal. The test was interpreted as normal. 

 

The main indication for an exercise stress test is to see if there is myocardial ischemia (lack of blood flow to the heart muscle due to blockage in a heart artery). Ischemia is present if the patient has chest pain or if there are diagnostic ST segment changes. However, the stress test is not ideal. The diagnostic accuracy for heart artery blockage is only about 70%, so it misses about 30% of the time. Other tests, such as a nuclear stress test (accuracy 85-90%), CT imaging of the heart arteries or cardiac catheterization are more accurate in picking out significant heart artery disease. Despite this, there is a lot of useful information to be gleaned from the exercise stress test. Exercise or functional capacity is a strong predictor of mortality and heart disease. The better the exercise capacity, the lower the risk of cardiac outcomes. Functional capacity is measured in METs. As we saw, METs are calculated and shown on the stress test report. To determine if the number of METs achieved is good, here are the formulas for average METs for men and women:

            Men:                Predicted METs= 18 – (0.15 x age)

            Women:          Predicted METs= 14.7- (0.13 x age) 

If the METs on your stress test are higher than the predicted, your functional capacity is good or high. If lower, then functional capacity is fair or poor. The data from an exercise stress test may also be used to formulate a personalized exercise prescription. For more information about exercise prescription see: http://sportscardiology.blogspot.com/2017/08/an-exercise-prescription-to-get-fitt.html

 

The exercise stress test can also predict prognosis. In general, the longer on the treadmill and the better the exercise capacity, the lower the risk for heart outcomes. Functional capacity is the most important parameter. Other prognostic variables include heart rate achieved, heart rate and blood pressure response to exercise, exercise induced chest pain and ST segment changes. To quantify prognosis, the Duke Treadmill Score was developed and has been in use since the early 1990’s. The score uses three variables: 1- exercise time, 2- ST segment changes, 3- presence or absence of chest pain. The formula is:

            Duke Treadmill Score= exercise time – (5 x ST segment deviation) – (4 x CP index)

ST segment deviation is 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, etc. CP index is 0 if there is no chest pain during exercise, 1 if there is chest pain, but the patient can still exercise through it, 3- if chest pain causes the test to be stopped. The Duke Treadmill Score ranges from -25 (highest risk) to + 15 (lowest risk). The one-year mortality for the low-risk category (score >=5) is only 0.25% but in the high-risk category (<= - 11) the mortality at one year is 5.25%. 

 

In addition to all of the above, the exercise stress test is used to determine the heart rate response to exercise (whether the heart rate increases appropriately), the blood pressure response (whether the blood pressure goes up too high or drops during exercise, either scenario being a high-risk characteristic) and to see if there are exercise induced rhythm problems.        

 

Aside from diagnosing heart artery disease, the exercise stress test provides a wealth of information that is important both for the physician and patient. Armed with the formulas above and a copy of your stress test report, you can have lots of fun. You can calculate your maximum heart rate (then take 85% of that to determine your target heart rate during exercise). You can determine your functional capacity (METs) and see how you stack up against the general public. You can calculate your Duke Treadmill Score. So sharpen your pencil, get your calculator out and get to work.

 

 

How To Read The Lipid Panel

You try to be a good patient. You schedule your general physical with your primary doctor every year. Your doctor sends you for blood work, which you have done. Once the results are available, you log into your patient portal. There they are, your lab results. However, you are confused. What do all those initials mean? What do the numbers mean? Which ones are relevant? Which ones should you ignore? Here is a general primer on how to read your lipid panel blood test.

Before we look at some test results, we need some definitions. Lipids are a broad group of molecules that include cholesterol, triglycerides, fatty acids and others. Lipids are involved in many biologic functions. Lipids don’t dissolve in the blood and have to be transported from where they enter the body (or are stored) to the site where needed. Apolipoproteins carry out the transportation of lipids. 

Now, let’s walk through some typical lipid panel results. We’ll start with the panel pictured above. The first line is Total Cholesterol, which in this case is 121 mg/dl. In general, cholesterol levels should be below 200 mg/dl. Total cholesterol is a marginally useful number. The next line shows the triglycerides, which are 46 mg/dl. Triglycerides are the fat in the blood. When we eat food, any excess calories are turned into triglycerides and stored in fat cells. When extra energy is required by the body, the triglycerides are released and used. Triglycerides and cholesterol are different types of lipids. Triglycerides are used for energy while cholesterol is used to build cells and proteins. A normal triglyceride level is less than 150 mg/dl. An elevated triglyceride level (over 150 mg/dl) is associated with excess risk for heart artery disease, heart attack and cardiac death. The next line is HDL Cholesterol at 67 mg/dl. HDL stands for High Density Lipoprotein. It is the “good” cholesterol. HDL transports excess cholesterol in the body back to the liver where it is metabolized and excreted. HDL is important. Low levels of HDL have consistently been associated with heart artery disease. However, the converse is not true; high levels of HDL do not protect against heart artery blockage, contrary to the urban myth that it does. Many patients when asked why they are not on medication for their high cholesterol state that it is because they have a high HDL. HDL levels above 39 mg/dl are ideal. Many studies involving many different medications have been tried to raise HDL. Unfortunately, no pharmacologic therapy has been proven to raise HDL and reduce cardiac outcomes. The next line is VLDL Cholesterol Cal at 11 mg/dl. VLDL stands for Very Low Density Lipoprotein and these particles travel with triglycerides. The VLDL value is not measured but calculated (thus the ”Cal”) as trigylcerides divided by 5. It is not a clinically useful value and can be ignored. 

The next line is the most important, LDL Chol Calc (NIH) at 43 mg/dl. LDL is Low Density Lipoprotein and this can be reported in two different ways. It can be measured directly, which not the usual case as it is difficult. Most of the time, it is a calculated value. There are at least three different formulas for calculating LDL. The simplest is the Friedewald equation where LDL= total cholesterol- (HDL+triglycerides/5). Other equations are the NIH (which is the one used in the example) and Martin-Hopkins formula. There are differences in the equations, but a recent study found that the differences are small and not clinically significant. Excess LDL builds up in the artery wall, forming plaque and leading to blockage which results in a heart attack or stroke. As the average LDL level rises, the chance of atherosclerosis/plaque goes up and the number of sites affected goes up as well. In general, the LDL should be less than 100 mg/dl. In patients who have had a heart attack or stroke or had a stent or heart bypass, the LDL goal is less than 70 mg/dl or even lower. The last line is the LDL/HDL ratio. This number is irrelevant and can be ignored; just concentrate on the actual numbers, especially LDL, HDL and triglycerides.

Here is another example of a lipid panel report. It has two new parameters, Cholesterol/HDL ratio and non HDL cholesterol. As with the LDL/HDL ratio the cholesterol/HDL ratio has no clinical relevance and can be ignored. The non HDL cholesterol is important. Non HDL cholesterol is a measure of the all of the atherogenic lipids molecules. It is a best estimate of all of the important lipids that cause plaque and blockage. The formula for non HDL cholesterol is simple: Total cholesterol – HDL. The ideal value for non HDL cholesterol is less than 130 mg/dl. 

So, this is how to interpret the basic lipid panel. What about advanced tests? What is available? What is useful? There is a test called the NMR Lipoprofile. It reports more in-depth parameters such as particle size and density. While there is some slight incremental value in these numbers in terms of cardiac risk evaluation, no cardiac society recommends it. The consensus is that the standard lipid panel is good enough to estimate and follow risk. One test that may be beneficial is Apo B. Remember that apolipoproteins transport cholesterol in the blood. Apo B is one of those transport proteins and it carries all of the atherogenic lipids: LDL, VLDL and Lipoprotein a (more about this in a bit). So, measuring Apo B gives a very good sense of how much risk of atherosclerosis is present. Apo B is a more accurate marker of cardiac risk than LDL or non HDL cholesterol. The difference may or may not be clinically relevant. Currently, Apo B is not routinely checked but that may change in the future. Lipoprotein a is a lipid particle that is 5 times more atherogenic than LDL. It runs in families and it is estimated that one in five people have an elevated lipoprotein a level. A lipoprotein a level should be checked if there is a strong family history for premature heart artery disease or if a patient has recurrent heart attacks despite low levels of LDL. Lipoprotein a levels less than 75 mg/dl are considered normal.

In summary, the basic lipid panel provides enough information for risk assessment and for following progress in the prevention of coronary artery disease. The important numbers to pay attention to, in order, are: LDL, HDL, Triglycerides, non HDL cholesterol and finally total cholesterol.

 

Additional resources:

LDL:

http://sportscardiology.blogspot.com/2022/03/cholesterol-years.html

 

HDL:

http://sportscardiology.blogspot.com/2022/10/how-high-is-too-high.html

 

Triglycerides:

http://sportscardiology.blogspot.com/2023/11/the-trouble-with-triglycerides.html

 

Lipoprotein a:

http://sportscardiology.blogspot.com/2021/04/

 

 

Plastics

 

"I just want to say one word to you... just one word...Plastics."

 

One of the many great quotes from the 1967 film “The Graduate” finds the main character, Ben, floundering and undecided as to his future. His future father-in-law tries to guide him and suggests a career in plastics. Over the ensuing 57 years, he certainly would have been proven correct from the business standpoint. Plastics are everywhere. The worldwide production of plastic has grown from less than 2 million tons in 1950 to about 400 million tons in 2020. Plastic production is expected to double by 2040 and triple by 2060. While plastics have made our lives better there is a downside. Plastic waste is ubiquitous in the environment.  Plastic bottles, plastic wraps for food and other plastic products are dumped in the ocean and found in the soil. These plastic products break down into smaller particles called microplastics. Microplastics are picked up by fish, especially tuna, oysters, and mussels. The burning of plastics results in the release of microplastics into the air. Humans are exposed to microplastics by ingestion (for example by eating fish) or inhaling air laden with these particles. The Center for Disease Control suggests that microplastics are present in the bodies of nearly all Americans. Microplastics have been found in the colon, liver, spleen and lymph nodes. Now we find out that plastics are present in our arteries. 

 

A study from the March 7 2024 New England Journal of Medicine was eye opening and thought provoking. The researchers examined plaque from patients undergoing surgery for blockage in their carotid (neck) arteries. 304 patients had plaque removed and analyzed. In 58% of patients, microplastics were found in their arteries. Over the next 3 years, the patients who had microplastics in their blood vessels were 4 times more likely to die or have a heart attack or stroke compared to patients without microplastics. The proposed mechanism is that microplastics penetrate the cells in the blood vessel wall, producing chronic inflammation and resulting in worsening plaque production and outcomes. The authors proposed microplastics as a new cardiac risk factor. The study generated lots of discussion in the medical community. The study itself had many flaws (single center, small number of patients). The bottom line is association does not mean causation. Microplastics may be associated with adverse cardiac outcomes but may not be causing the adverse events. Further studies are needed to confirm the findings.

 

Plastics may be another in a growing number of environmental pollutants that have cardiovascular consequences. Known risk factors are air pollution (http://sportscardiology.blogspot.com/2017/08/paris-polluted-arteries-r-not-in-style.html)

and noise pollution 

(http://sportscardiology.blogspot.com/2020/02/the-cardiac-consequence-of-sound.html). Pollution is defined as the presence of a substance in the environment that can cause adverse health effects as well as damage to the ecosystem. Air pollution is the most important environmental cardiac risk factor. Of all of the air pollution related deaths, cardiac disease accounts for 45% of the total, while lung disease is only 8%. In addition, there is soil and water pollution due to farming and industrial activity as well as waste disposal (plastics falls into this category). In addition to plastics, other pollutants include pesticides and heavy metals. Despite different chemical compositions, pollutants lead to cardiovascular disease through common pathways. Pollutants trigger stress reactions leading to systemic inflammation leading to plaque and blockage in arteries, increased blood clotting, and abnormal hormonal secretion. 

 

Controlling pollution is important for overall cardiac health. Decreased air pollution over the past 50 years has contributed to the decline in overall cardiac mortality in that time period. Given the scope and magnitude of the pollution problem, what can a single person do? While most of the heavy work decreasing pollution must be left to governments and industry, there is much the individual can help with. To decrease exposure to air pollution one can stay indoors during high pollutant levels, commute by public transportation or bike or on foot and avoid spending time in high pollution areas, such as near highways. In addition, plastic pollution can be decreased by minimizing single use plastics (products designed for one use and then thrown away). This includes food and beverage containers, bottles, straws, cups, plastic forks and knives and disposable plastic bags. Follow some of these easy measures and your arteries will thank you. 

 

 

 

The Dawn of a New Day

 

When the child of morning, rosy-fingered Dawn, appeared, Odysseus rose and led the way to the place of assembly, which was near the ships.

Book VIII, The Odyssey

Homer

 

The phrase “rosy-fingered dawn” is an epithet (a descriptive term) used many times by Homer in both the Iliad and the Odyssey to say, “the break of day”. The term also signifies a fresh start to a new day and a tribute to the trials and tribulations of the day. How does the body handle the “rosy-fingered dawn” and rising from sleep to face a new day? What physiologic changes occur and how do those changes impact heart health?

 

The human body ticks to a 24-hour clock. This clock determines changes in our bodily functions which guide us between a rest stage (sleep) and an active stage. Our internal rhythms are synchronized with the world through interactions with light. These variations are called circadian rhythms (the term circadian is from Latin, circa which means around and dies which means day; around the day). As the rosy-fingered dawn breaks, we sense the presence of light. This results in the secretion of a number of hormones which serve to rouse us, “rev” us up, to get ready for a new day. The hormones include adrenaline and cortisol, which result in an increase in blood pressure and heart rate, increase our wakefulness, increase body temperature and get us ready to be become active. On the other hand, as light fades, the body secretes melatonin and decreases adrenaline and cortisol, getting us ready for the rest phase, sleep. Disruptions to the well-controlled circadian rhythm can lead to various chronic illnesses including heart disease. 

 

Circadian rhythms are controlled by a number of biological clocks. A central clock is located deep in the brain and regulates the clocks located throughout the body. These peripheral clocks are found in nearly all of the tissues of the body, especially in the gastrointestinal system, the nervous system, the liver and the heart. The circadian clocks are molecules within the cell that provide feedback loops timed to a 24-hour cycle. There are clocks in the heart muscle as well as in the wall of blood vessels. The heart muscle clocks orchestrate cellular processes, ensuring that they occur at the right time of the day. Growth and repair of heart tissue takes place during sleep or rest periods. If this circadian pattern is broken, then cardiac pathology ensues. During a normal day, there are fluctuations of up to 20% in various cardiac parameters. For example, blood pressure is lowest during sleep and highest in the early morning hours.  This is due to the release of the hormones responsible for rousing us at the beginning of the day.  Similarly, the greatest risk for a heart attack or stroke is around 6 AM. This is a direct result of the early morning changes with increased blood pressure and heart rate leading to increased stress with the heart’s blood vessels and an increase in clotting factors caused by the release of hormones. In addition, life threatening arrhythmias and sudden cardiac arrest peak around 6 AM.  

 

Maintaining normal circadian periodicity is important for preventing disease and maximizing longevity. Disruption of the normal circadian rhythm is detrimental and leads to a variety of chronic illnesses. Disruption can be genetic, environmental or behavioral. Irregular sleep and eating schedules misalign the clocks. It is important to keep sleep timed with lack of light, i.e. night-time. Irregular sleep schedules throw off the biological clocks so they can’t synchronize properly with the light-dark cycle. Changes such as jet lag and daylight savings time can disturb internal clocks and lead to cognitive impairment and increased risk for heart attack.  Shift workers who sleep during daytime are especially prone to circadian disturbances. Shift work is a risk factor for heart disease, diabetes, obesity and hypertension. It increases cholesterol and triglyceride levels and increase inflammation. Sleep timing is important as well. Evening types, people who have later wake up and bedtimes, are at increased risk compared to morning people. Evening types have a higher incidence of cardiac disease, diabetes and obesity. Therefore, it is important to keep a regular sleep schedule. Meal timing is another factor as food serves to synchronize the biological clocks. Eating late at night also leads to cardiac disease, diabetes, obesity and high cholesterol. Shifting food toward the beginning of the day reduces those risks. This was proven in a recent study. Late eaters, people whose largest meal of the day was after 12:38 PM, had higher risk for obesity than people whose main meal is at lunch time. Having smaller meals throughout the day was better than eating three “square” meals. In addition, intermittent fasting, food intake restricted to early morning to 6 PM with an overnight fast, can reduce weight and protect against metabolic disease. 

 

To every rule, there is an exception. In this case, the exception lies in a Blue Zone. Blue Zones are areas around the world where there is exceptional longevity, with many people in the population reaching 100 years of age. Blue Zones have been identified in Japan, Costa Rica, California and on the Mediterranean island of Ikaria, Greece. The Mediterranean lifestyle seems to counter the circadian rhythms noted above. Dinner is served after 9 PM at night and bedtime occurs late as well. In addition, there is a day time siesta, so sleep patterns are irregular. On the other hand, the main meal is lunch. 

 

There are numerous factors involved in greeting many rosy-fingered dawns. Listening to our biologic clocks and following our circadian rhythms can help stave off disease and increase longevity. In order to do this, regular sleep habits and timing sleep patterns to light and dark seem prudent. In addition, shifting caloric intake to earlier in the day, eating smaller meals and doing some overnight fasting will improve the chances of seeing the dawn of a new day. 

 

 

Cold-Hearted

 

CLEOPATRA: Ah, dear, if I be so,
From my cold heart let heaven engender hail,
And poison it in the source

 

The expression cold-hearted means showing no understanding, no feeling towards another. It is unsympathetic, unemotional, uncaring and cruel. If used in a sentence it might look like this: “The cold-hearted landlord evicted the poor family with a sick child”. The first known use of the adjective cold-hearted is in Shakespeare’s play, “Antony and Cleopatra”. Certainly, Cleopatra could be considered cold-hearted due to her various plots to overthrow her brother and rule Egypt. Heart attacks can also be considered cold-hearted. A heart attack does not discriminate; it can affect men or women, young or old, rich or poor. It can strike at any time of the day or night, often without warning. Despite that, heart attacks do have some predictable variation. For example, heart attack risk changes with the season of the year and is associated with extremes of temperature, both hot and cold.  The only known example of Cleopatra’s handwriting is a single Greek work, γίνεσθοι, which she wrote on a papyrus addressed to a tax collector in 33 BC. It translates to, “so be it” or “make it happen”. Heeding the queen’s order, we will now “make it happen” and outline when heart attacks are the most cold-hearted.  

 

A heart attack occurs when a plaque in a heart artery breaks open. When the blood is exposed to foreign material (such as an exposed plaque), it does what it is supposed to do and forms a blood clot within the artery. If the clot totally obstructs the flow of blood, the type of resulting heart attack is called a STEMI (ST elevation myocardial infarction). If there is still some residual blood flow through the blockage and clot, then the heart attack is a nonSTEMI. For both types of heart attack, there is a U-shaped association with temperature. There is an increased risk for heart attack on very cold and on very hot days. Since we are in the throes of winter, we’ll concentrate on the cold weather effects on the heart. An increase in heart attacks and heart attack deaths in the winter was first noticed in the 1930’s. A large database studied heart attacks from the 1980’s and 1990’s and quantified the risk. A seasonal distribution was confirmed; there were 50% more heart attacks in the winter months compared to the summer time. The peak number of cases were in January, followed by February, March, November and December. Another series, also from the 1990’s, concluded that coronary events were 20-40% more likely to happen in the winter and spring versus other times of the year. One other study (1980’s-1990’s) also showed that the month with the highest mortality rate due to a heart attack was January.  Lastly, a study from Minnesota (1979-2002) showed that a temperature below 0 degrees Celsius (32 degrees Fahrenheit) was strongly associated with death due to a heart attack.

 

A lot has changed in the 25 to 30 years since this data was reported. At least two factors have changed significantly. First, heart attack care has vastly improved. Catheterization and coronary stenting during the acute event (especially STEMI) restores blood flow and subsequently fewer patients die from their heart attack. Secondly, there is global warming. Since the 1950’s each decade is hotter than the previous one. Globally, the temperature has risen 0.17 degrees Fahrenheit each decade, with steeper rise since the 1970’s. Has the combination of warmer weather and improvement in cardiac care reduced the risk for having a heart attack in winter? To answer this a group from Germany looked at temperature and heart attacks in two distinct periods, 1987 to 2000 and 2001 to 2014. During those time periods, the average daily maximum temperature rose from 14.5 degrees C (58.1 degrees F) during 1987-2000 to 15.1 degrees C (59.2 degrees F) in 2001-2014. They found no significant decline in cold related heart attacks when comparing the two eras. Heart attack risk remained high with very cold temperature. Another group studied data from five European countries between 1994 and 2010. They also found that cold weather was associated with an increased risk for heart attack, without change over time. With a drop in temperature from 5 degrees C (41 degrees F) to – 5 degrees C (23 degrees F) there is about 20% increased risk for heart attack and cardiac death. Lastly, a study from Taiwan looking at data from 2000 to 2017 showed that below 15 degrees C (59 degrees F), every 1 degree drop in temperature increased the risk for heart attack by 0.9%.

 

The relationship between cold weather and heart attack has been seen across the globe, in different eras, with different populations and with different weather conditions. It even holds up locally. Over the past five years, the month with the second highest risk for STEMI at Robert Wood Johnson Somerset has been January. How does cold affect the heart and who is at risk?   Elderly patients (over 65 years old) are more susceptible to cold related heart attacks than younger people. The highest risk are older patients with hypertension (high blood pressure). Cold weather increases blood pressure and causes spasm of the heart arteries. This leads to an increase in the work load of the heart. Cold weather increases the thickness of the blood, increases clotting factors and increases inflammation. All of the factors can cause a vulnerable heart plaque to open and trigger a heart attack. The winter months also increase the risk for respiratory infections (for example, flu) which act as a trigger for a heart attack. Other cold related factors include less physical activity, weight gain and holiday stress adding to the risk for heart attack in the winter. 

 

For the elderly heart patient, the cold weather can be as deadly as an asp. For those with significant heart disease, here are some cold weather recommendations. Skip strenuous activity outdoors when the temperature (or the wind chill) is below 30 degrees F and do your exercising indoors. When outside, try to cover all exposed skin. Make sure the heating system in the house is working and use it! The World Health Organization suggests keeping the indoor temperature above 68 degrees F. Lastly, relax with a cup of tea by the fire and count the days until spring. 

 

 

 

 

Vive La Resistance (Training)!

 

The holidays are over. It’s a new year. The decorations are stored away and the New Year’s resolutions are made. What are the top New Year’s resolutions? According to Forbes magazine, the number one New Year’s resolution for 2024 is to improve fitness and exercise more. That is a worthy goal, but what type of exercise should be targeted in 2024? Another top resolution per Forbes is to lose weight. That is also a good goal, but how long will it take to get the holiday weight off?

 

If you are feeling bloated and have gained weight during this holiday season, you are not alone. A study tracked the change in weight for participants in three countries, the US, Germany and Japan. In these three diverse countries, weight started to go up in November and peaked on New Year’s Day. On average, it took until March to lose the weight gained and get back to the pre-holiday weight. How can holiday weight gain be prevented? One strategy is to have smaller meal portions at the family table and eat fewer desserts. Another is to exercise. It has been shown that people who continue exercise training during the holidays can prevent weight gain.

 

It is established that exercise will help with losing weight. It is established that exercising more is the top New Year’s resolution, but what kind of exercising should be done? Aerobic training has well known benefits. The scientific evidence is vast and consistent in showing that cardio exercise (such as running, cycling, swimming or hiking) has many cardiovascular benefits, in addition to increasing longevity. Therefore, aerobic exercise should be a main component of any exercise regimen. What about resistance training? It has been perceived that aerobic exercise is better than resistance training but in fact each is important. It has been estimated that only 28% of US adults perform any form of resistance exercise. Resistance training lowers the risk of dying from any cause by 15% and lowers the risk for cardiovascular disease and death by 17%. Resistance exercise will lower systolic blood pressure by 4 mmHg and diastolic blood pressure by 2 mmHg. It will lower fasting blood sugar by 2 to 5 mg/dl, increase HDL cholesterol (2 to 12 mg/dl), lower total cholesterol (by 8 mg/dl) and reduce triglycerides (7 to 13 mg/dl). Combining resistance and aerobic training gives even greater benefit in terms of weight reduction, diabetes prevention, cholesterol lowering, cardiovascular disease prevention and mortality reduction. 

 

In addition to cardiovascular prevention, resistance training has another very important benefit. As we age, there is progressive decrease in muscle mass and strength. With age, activities such as standing up, sitting down, climbing stairs and maintaining balance are as important as cardiac fitness.  Most of the loss of muscle mass occurs after age 60. Men will lose, on average, 33% of their muscle mass between the ages of 60 and 97. Women will lose 26%. With the loss of muscle mass and strength, significant health problems may ensue as the risk for falls increases by 60% and risk of bone fracture increases by 84%. Resistance training helps to build and maintain muscle strength. Resistance training improves muscle mass (by increasing leg and total body musculature) and muscle strength (by improving handgrip strength, chest and leg press) as well as overall physical performance (by improving sitting to standing, walking speed). 

 

What does a resistance training prescription look like? Resistance training can include free weights, body weight (for example push-ups, squats), machine weights or resistance bands. Resistance training doesn’t necessarily lead to “bulking up” and can be done without great expense (a gym membership or a major set of weights aren’t needed). Ideally 8 to 10 different exercises involving major muscle groups are done (for example, push-up, squat, abdominal crunch, biceps curl). Each exercise is performed for 8 to 12 repetitions. Weight and intensity can be increased gradually over time. Resistance training should be done two or more times per week for maximal muscle strengthening and cardiovascular benefit. 

 

As we get older, we are limited by our heart and/or our orthopedics. Resistance exercise helps with both. So this year resolve to pump up your fitness, build some muscle, lose weight and improve your cardiovascular profile by incorporating resistance training into your exercise routine.