Introduction

Coronary atherosclerosis (blockages of the coronary arteries) is the major cause of death in this society, and often exists in people at fairly “low risk” and with no symptoms.  Heart attacks and sudden death may occur without warning.  Finding blocked heart arteries is a challenge, however.  They are relatively small structures, and like the heart itself, are in constant motion.  They are not seen using regular x-rays nor ultrasound techniques.  Indeed, even advanced techniques such as “regular” CT scanning and MRI (Magnetic Resonance Imaging) cannot visualize them secondary to their movement.  Physicians therefore use techniques that predict the presence of atherosclerosis that are less precise than actually visualizing the vessels.  Physicians often assess “Risk Factors” (such as smoking, high cholesterol, diabetes, age, sex, and family history of heart disease).  Indeed, people with much higher risk than the rest of the population can be identified, but many cases can be missed.  Indeed, most cases of coronary disease develop in people with average risk factor profiles.  Furthermore, some people with “high risk” may never develop coronary disease. 

Techniques such as stress tests are useful, but only for discovering blockages that have grown to the point where they cause a lack of blood supply to the heart.  Even advanced blockages may be missed. Stress tests are incapable of finding early atherosclerosis since they rely on the presence of advanced blockages.  This is particularly frustrating since such early blockages can have the most done to prevent progressive problems.  Angiograms are extremely accurate at finding plaques that have grown  from the walls of the arteries and block the flow of blood.  These tests are expensive, time-consuming, and are associated with at least modest risk.  Again, the mildest blockages are missed.  All of these techniques  are limited in their ability to follow the course of the process over time.

 Ultrafast CT is a quick, easy, and relatively inexpensive technique which allows the arteries to the heart to be directly visualized.  It images calcium in the vessel wall as well as the arterial channel to some degree.  It can overcome some of the deficiencies of the other techniques.  This allows for simple, early detection of atherosclerosis and the potential to follow the course of the process over time. 

 Ultrafast CT is not without its detractors however.  Many physicians, including myself, have approached this test with a great deal of suspicion.  The test had been hyped by many in a position to further their financial health, and the potential for inappropriate use has been realized on many occasions.  However, much has been learned – it is clear that there is much to be gained from its proper use.   While improper utilization can lead to inaccurate diagnosis, further diagnostic testing, and unnecessary treatment, many people can benefit.  Careful selection of patients, and careful interpretation of the results in light of multiple factors in the patient’s history is essential to maximizing the potential of the technique.

To learn more, continue with the more detailed discussion.  The following subjects are covered:

The challenge of finding heart disease before it strikes  
Who’s at risk? 
Traditional techniques of finding blocked arteries  
The advantages of Ultrafast CT scanning  
What exactly does the Ultrafast CT show?  
What is a “Calcium Score”?  
How is the test done?  
Who should have the test?  
Is it covered by insurance?  
My Ultrafast CT came out fine.  That shows I can continue smoking and/or eating a bad diet, etc.  
In summary

The challenge of finding heart disease before it strikes

Despite the great advances in heart disease diagnosis and management over the last two decades, one of the great challenges remains:  Finding heart disease BEFORE it strikes.
Many people realize that blockages of the arteries to the heart can be dangerous, but few may realize just how dangerous.   When arteries to the heart become partially blocked over a period of time, the afflicted person may begin to experience symptoms of “angina”, discomfort that occurs because of insufficient blood supply to the heart muscle through the narrowed arteries.  However, about one-third of people with blocked arteries only find out they have a problem when they have an actual heart attack.  Worse yet, one out of four do not have any warning whatsoever, and suffer sudden death as the very first sign of heart disease.  Waiting for symptoms of heart disease to occur is not a very good strategy!

Who’s at risk?

Physicians have realized the potential for these catastrophes, and indeed work hard to try and identify those at high risk.  This explains why we measure and treat high blood pressure, high cholesterol, and diabetes, and why we stress the absolute need to discontinue smoking.  Treating people with these “risk factors” can indeed be effective.   Some people with heart disease however have no risk factors, or only minimal problems.  Indeed, most heart attacks that occur will occur in people with cholesterol levels in the “normal” range, and risk factor profiles that are not too impressive.

Traditional techniques of finding blocked arteries

There are several varieties of “stress tests” which can be utilized to try and find people who may have blockages.  These can show whether there are blockages of sufficient severity to decrease the amount of blood traveling to the heart when the heart muscle is working hard. 

These tests are useful, but have several shortcomings:

• They are “positive” only when blockages are pretty far advanced and suffer from an inability to find problems at an early stage.
• They are not 100% accurate, sometimes failing to show abnormalities when blockages exist, or on the other hand suggesting there are problems when they don’t exist.

Heart catheterization  is a test where “dye” (actually a material that provides contrast on the inside of the arteries so that the channel where blood flows can be seen) is used to see if there is any narrowing.  It too is a very useful tool for finding blockages, and remains the best way to judge the severity of the narrowings.  However, it also has problems when it comes to the task of finding heart disease early:

• It is “invasive” and is associated with significant risks, such as bleeding, heart attack, or stroke.  These are not frequent events, but certainly lead to caution as a screening tool.
• While it is virtually 100% accurate in finding significant blockages, it also suffers from an inability to find “early” disease.  A substantial amount of atherosclerosis may exist in the walls of the arteries that are indeed a marker of very high risk, yet the inside looks smooth and “normal”.
• It is expensive and time-consuming.

The advantages of Ultrafast CT scanning

“Computed tomography” (“CT”) has been used for two decades, and remains an exciting means to “see inside” the body using x-rays.  CT differs from regular x-rays in that the x-ray beam makes multiple  “passes” through the body, and is able with the aid of computers to produce highly accurate pictures of body structures. 
The heart and its arteries however have been a challenge to CT scans because of two factors:  the heart arteries are relatively small, and more importantly, the heart is virtually always in motion. 

Ultrafast CT, by timing its scans to particular moments in the cardiac cycle, can virtually “freeze” the view of the heart, and allow the scan to show the arteries.  In contrast to any of the other techniques noted to this point, the Ultrafast CT not only sees the inside of the artery where the blood flows, but also sees the walls of the arteries themselves, the place where cholesterol and other substances collect.

What exactly does the Ultrafast CT show?

Ultrafast CT images all parts of the heart including the muscle and valves.  Some very useful images can be made of blood flow, and heart muscle function can be analyzed.  Ultrafast CT can also be utilized to diagnose problems such as pulmonary embolism or dissection of the aorta.

The most exciting part about Ultrafast CT however is the ability to see the coronary arteries, the vessels that supply blood to the heart .  It is important to realize that these studies are not the same as an angiogram, where contrast material (“dye”) is injected directly into the artery by catheters.  Indeed, catheters make much more accurate pictures of the inside of the arteries.  These blockages may also be seen with Ultrafast CT, simply not as well.

Ultrafast CT shines however in discovering the process of atherosclerosis at a more basic level:  It sees the development of lesions before they begin to interrupt the path of blood flow by imaging the changes that occur in the vessel wall itself.  It owes its success to its ability to image calcium in the vessel walls.  While calcium is not the major problem when it comes to blocked arteries (the most important substance is cholesterol), the appearance of calcium in the wall of the artery is associated with active atherosclerosis in many cases.  Indeed, removing the calcium from blocked vessels, as is the basis of “chelation” therapy (see link) has really very little to do with changing the course of atherosclerosis.  Calcium is however an excellent substance to use for imaging.

What is a “Calcium Score”?

The amount of calcium that is deposited in atherosclerotic plaque varies from person to person, from males to females, and certainly varies with a person’s age.  Imaging calcium is exciting, but it also has its own limitations, and the test must be interpreted carefully, taking many factors into consideration before deciding that the test reliably indicates the presence or absence of disease (see “Who should have the test?”).

How is the test done?

It is very simple to perform.  There is no prep before the test.  Leads for an electrocardiogram are placed.  Sometimes contrast material is used, and if so, an intravenous line will be placed.

One simply lies down on the examination table while passing through the “donut” of the CT scanner.  About 15 minutes later, the test is completed.

Who should have the test?

Well, as usual, it depends.  Age, gender, and the presence of other risk factors all play a role in this recommendation.  The most important points however relate to age and gender.

It is very unusual for people, particularly women, to have calcium in their vessel walls under the age of 40.  This is true even if there are significant blockages present.  The process simply has not been going on long enough to be associated with the deposition of significant calcium.

Likewise, calcium is present in many people over the age of 65.  Thus, the reliability of the test is less in older age groups, particularly in males. 

There is a large group “in the middle” of these age ranges for whom the test has demonstrated a substantial correlation with future heart attacks, bypass surgery, and prognosis.  Indeed, this is the group in whom coronary disease is likely to strike prematurely.  Those with multiple risk factors or a family history of coronary disease may be productively screened at somewhat younger ages. 

 At least two studies have shown the promise of assessing the success of medical treatment of high blood pressure and cholesterol levels with this technique, suggesting that adequate medical therapy slows the progression of calcium deposition.  If such research continues to be positive, this would be exceedingly useful.

Is it covered by insurance?

Many insurance companies do cover this procedure now, and Medicare does have a code that can be used for billing.  However, as in all such matters, the rules are complex and ever changing.  You or the facility that bills you will need to discuss this with your carrier.  The test is relatively inexpensive however, and some people prefer to pay with cash since in that case the insurance company has no legal access to the results.

My Ultrafast CT came out fine.  That shows I can continue smoking and/or eating a bad diet, etc.

No, No, No!  That’s not the point at all.  If you play with fire, you will get burned!

Smoking is a health risk that certainly is associated with heart disease, but also causes cancers at multiple sites in the body, not to mention emphysema and other lung disease.  You absolutely need to stop smoking regardless of the results of the Ultrafast CT (see “Stopping Smoking” ).

This test is designed to allow you and your physician to assess your risk of heart disease and implement those health practices and therapies that will allow you to pursue a long and healthy life.  It is not designed to allow you to follow improper health habits!

 A scan that is “normal” or “low risk” is not a guarantee of either, now or in the future.  Proper diet and exercise are still among the very most important ways to live longer, and enjoy doing it!

In summary

This has been a fairly complex subject.  Now that we’ve covered it all in detail, let’s look at it briefly again.

• Coronary atherosclerosis is the major cause of death in this society, and often exists in people at fairly “low risk” and with no symptoms.  Heart attacks and sudden death may occur without warning.
• Using a model that predicts coronary disease based on the presence or absence of factors such as smoking, high cholesterol, diabetes, age, sex, and family history can be useful in predicting the incidence of disease in a population.  However, this is not nearly as useful in evaluating individual cases.  Many cases can be missed.  It is very important to realize that most cases develop in people with average risk factor profiles.  On the other hand, some people with “high risk” may never develop coronary disease.
• Stress tests are useful, but only for discovering blockages that are already so severe as to cause a lack of blood supply to the heart.  They do nothing to find early atherosclerosis, the group in whom the most can be done to prevent future events.
• Angiograms are extremely accurate at finding plaques that have grown from the walls of the arteries and block the flow of blood.  These tests are expensive, time-consuming, and are associated with modest risk.  Of perhaps more importance, the mildest blockages are missed.
• All of the techniques noted above are limited in their ability to follow the course of the process over time.
• Ultrafast CT is a quick, easy, and relatively inexpensive technique which images calcium in the vessel wall as well as the arterial channel to some degree.  It can overcome some of the deficiencies of these other techniques.  This allows for simple, early detection of atherosclerosis and the potential to follow the course of the process over time.  Careful selection of patients, and careful interpretation of the results in light of multiple factors in the patient’s history is essential to maximizing the potential of the technique.