Robert L. Blum, MD, PhD

 

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            Tim Russert: Dead at 58

The Case for Coronary Artery Calcium CT Scan

 Tim Russert

 

            I was shaken by Tim Russert's death from a heart attack at age 58 on June 13, 2008. 

As one of NBC's top newscasters, he was beloved by millions of Americans who would watch him

each week on Meet the Press, as he unrelentingly asked the tough questions to our politicians.

 

            When men (and less frequently women) die suddenly in middle-age

that death  is almost always caused by coronary artery thrombosis, a blood clot suddenly forming in one of the two arteries supplying the heart muscle itself.

 

            (Although the heart pumps all five liters of blood per minute,

 it itself gets its oxygen and nutrients only from the blood supplied by the 4 mm diameter

right and left coronary arteries that run on its surface, starting from the aorta.)

 

            Heart attack caused by coronary artery disease is the number one killer

in the United States and Western Europe. It causes over half a million deaths (USA) per year.

Stroke is the second most common cause of death, and it occurs by exactly

the same process, obstruction of the arteries to the brain.

 

            Heart attacks occur when a coronary artery suddenly plugs up.  Here's how it happens.

Over decades plaque builds up on the side of the artery.  Plaque starts out as fat deposits

in the internal wall of the coronary artery.  After many years that fat becomes calcified

and stoney hard. Heart attacks happen when a plaque ruptures, lifting off the wall of the artery,

and precipitating a blood clot that completely plugs it.  The heart muscle then has no blood supply

and dies.  If the heart can't pump blood, then the patient dies as well.

(This is a simplification, but it will do for now.)

 

            As an ER physician I have, of course, taken care of hundreds of patients

with hearts attacks.  We see them everyday. However, my involvement with heart attack

also has a personal angle

 

            Arteriosclerosis (Latin for hardening of the arteries) killed my grandfather in middle age.

Arteriosclerosis killed my father, and, as a young physician, I watched that process unfold in him.

It started with angina in his fifties, heart attacks in his sixties, and strokes and death in his seventies. I helped wheel him into the operating room when a leg was amputated for clogging

of the arteries in his legs.

 

            Armed with my knowledge of medicine and having watched my father's tragic disease,

I have striven all my adult life to avoid arterial disease and its attendant ravages.

 

            I have always been athletic:  tennis in high school, running three miles a day from age 18

to age 33,  vigorous hiking and cycling during the past thirty years.  With all that physical activity

I've always thought that I myself would never get atherosclerosis.

 

            My cholesterol scores were, I thought, reasonably ok - about 230 or so in my forties

and early fifties -  (what constitutes normal has steadily decreased in the past twenty years).

 And, I started taking statins about eight years ago with a resulting total cholesterol of about 150,

 LDL cholesterol of perhaps 80 or below, and HDL cholesterol of 42 (not great).

 

            I've never smoked and my blood pressure has always been normal.

 

            Given all that, it was quite a shock to me to find that, in fact, I have arteriosclerosis.

In another essay I'll talk about what might have gone wrong.

 

            Our subject today is how I found out.

 

First, I must say that I have never had any symptoms of narrowed arteries.

I hiked 14,500 foot Mount Whitney a couple of years ago and every year climb Half Dome

in Yosemite with my son.  I also regularly hike or bike a local 2,000 foot mountain

about once a week with friends.  So, no symptoms but ...

 

carotid ultrasound

A lengthwise cross-section of a patient's (not mine) right internal carotid artery.
Blood is flowing from the upper right to the lower left. It is flowing around
a large (black) obstructing plaque. The speckled colors at the lower left are
caused by post-obstructive turbulent flow.

 

 

Wake Up Call #1 : My Carotid Ultrasound

 

We ER docs at Kaiser were learning to do bedside ultrasounds about five years ago.

(Ultrasound is now a regular part of the ER armamentarium. We mainly use it to diagnose

 problems related to early pregnancy like miscarriage or tubal pregnancies.)

At the end of our teaching session, driven by curiosity, I asked our instructor to scan

my carotid arteries. The carotids take off directly from the aorta, and they are an

easily accessible place (in the neck) to determine the state of your arteries.

As the carotids go, so go the coronaries. The exam takes a few minutes

and involves nothing more than the tech's moving a probe around on your neck.

 

When my left carotid was being scanned, one of my colleagues gasped and said

"what the hell is that?" I thought my colleague was just joking at my expense;

however, the teacher said they were seeing an irregular calcified plaque.

In one view it looked like an iceberg; however, in the transverse cross-section

it appeared that it was in actuality only about a twenty percent obstruction.

 

The next day I had a a formal ultrasound (larger, higher resolution machine)

that confirmed this finding and, furthermore showed that my flow velocities were all normal.

(With significant obstruction the blood flow speeds up.  Picture what happens

when you partially obstruct the end of a running garden hose with your thumb -

the water then jets out. If the flow velocities are normal, then the obstruction is not significant.)

 

When we're young we think we're going to live forever.  This was particularly true for me,

because I'm extremely health conscious and would, in fact, love to live forever.

Nothing thrills me as much as watching the future unfold.

 

Unfortunately, that little episode brought my notion of living forever unscathed

by time to an abrupt halt.  I WAS MORTAL! #$%^&*! I was going to die

of the same disease that killed my father and grandfather.

 

I increased my dose of statins, was somewhat more assiduous about my diet and exercise,

and I comforted myself with the thought that twenty percent obstruction wasn't all that bad.

Also, it seems likely that that calcified plaque had probably been growing for decades

and wasn't likely to go anywhere. (This has proven to be the case.

 I've had a few ultrasounds since then and there has not been any progression.)

 

Wake Up Call #2: My Coronary Artery Calcium Score (CT)

 

A coronary artery calcium score or CAC is done by ultrafast CT in one breath hold.

The CT is synchronized to your electrocardiogram and its purpose is to image

calcified plaques (if any) in your coronary arteries. (There should be none.)

Nowadays this test is usually done with a 64-slice CT scanner, but

the test has been available with ultrafast e-beam CT scanners for about fifteen years.

(By the way this is completely non-invasive: not even an IV is required.

Do not confuse this with a coronary arteriogram, which is highly invasive.)


By the way I need to mention that the CAC like any CT scan incurs a lot of radiation

exposure. It is many times the radiation from a typical chest x-ray. My opinion is that
in the appropriate setting the information gained will outweigh this risk. But this is definitely
an issue that must be weighed and discussed with your physician.

 

A good friend of mine’s dad had a coronary CT scan about ten years ago.

The dad, who was energetic, delightful, and a well-known local citizen, had

arteriosclerosis on his CT that was practically off the scale. Despite this

he was completely free of symptoms (taking BP meds, but not on statins).

Ignoring the test he continued to live the life of a gourmet/gourmand and died suddenly

of a heart attack about three years later in his early sixties. (His son,

sensitized to the risk factors, began statin therapy at age 46.)

 

The test costs about $300, is usually not covered by insurance, and is definitely

not a routine part of any internist's screening exams like an ekg or chest x-ray

or cholesterol. Given those barriers I myself did not get the test until 2006.

(Stupid me.  The carotid ultrasound should have motivated me.)

I was persuaded ultimately by a discussion in Fantastic Voyage, the health book by

Ray Kurzweil and Terry Grossman. To get the test I had to go outside of Kaiser, my insurer.

(Kaiser's policy, in common with many other institutions, is that the test provides

no new actionable information that can't be gotten by other means.

 I disagree and present the case for a coronary calcium scan below.)

 

My test was rapidly completed and, full of optimism, I cheerfully asked the CT tech,

"well, am I going to live?" The tech, not full of optimism, said "it's always

the doctors and nurses."  Suddenly a lot less cheerful, I asked "what's going on?"

 

As I reviewed my scan with him it was obvious that my cardiac scan was not ok.  

There were obvious calcified plaques and my total calcium score was

above normal for a man my age. Somehow all my running, hiking, biking,

and clean living had not worked.

 

What had gone wrong?  If a conscientious, physically fit physician,  

whose father and grandfather had died of coronary disease,

couldn't prevent hardening of the arteries then what hope can there possibly be

for unmotivated civilians?  (This also motivated me to write the accompany essay on
Synthetic Coronary Grafts.) This question I will begin to address below,

but for now my focus is on getting diagnosed.

 

coronary calcium

 

            The Case for a Carotid Ultrasound and/or a CT Scan for Coronary Calcium

 

            I am writing this essay to give you help that you may not get

from your family physician or internist.  Most health plans and insurance companies

will not pay for Coronary Calcium Scans and the indications for a Carotid Ultrasound

are quite limited.  These tests have, however, changed my life

and provided information that I absolutely needed to know.

 

There are two issues.

1) Do the tests provide information that is not available from cheaper blood tests?

2) Suppose your ultrasound or CT shows calcified plaques. Can you do anything about it?

 

            Do the imaging tests provide new information? Absolutely!

While it is clearly important to measure and to know your

blood pressure, cholesterol (total, LDL, HDL) and triglycerides, dietary intake of fats, etc.,

those are all indirect influences on amount of plaque in your coronaries and carotids.

What really counts is what is actually there.  Why guess or use indirect measures

when the radiologists or ultrasonographers can actually see it and measure it.
(The x-ray exposure is a real safety concern, as I mentioned above, and is particularly
an issue when contemplating doing serial CT's over time.
This is not an issue with ultrasound.)

 

            Let's say the imaging tests show plaque build-up. Can you do anything about it?

Absolutely!  This means that your interventions need to be persistent and aggressive:

maximizing calorie restriction and weight loss, optimizing diet (mainly vegetarian),

optimizing exercise, and probably taking statins and other anti-lipid drugs in consultation

with your physician.  For many people these are huge, life style changing interventions

that they would not undertake without these tests.

 

            The issue of whether atherosclerosis is reversible warrants a major discussion.

Here, suffice it to say that the answer is a qualified yes.  Cardiologists divide plaque into

two categories: calcified plaque and vulnerable plaque.  The calcified plaque is like a statue.

 It is hard as bone and removing it requires a rotary instrument like a dentist's drill.

The good news is that, like a statue, its not going anywhere.

 

            Vulnerable plaque, on the other hand, is soft, lipid-filled plaque that can accumulate

and change shape in a matter of days.  This is the type of plaque that medical scientists

have implicated as a major cause of heart attacks and stroke.   Vulnerable plaque

can be abruptly lifted up by the blood stream and cause a sudden blockage of the artery.

Fortunately, vulnerable plaque appears to be susceptible to reversal by statin drugs and by diet.

(Vulnerable plaque can be directly seen by IVUS or intravascular ultrasound - a highly invasive test.)

 

            Shrinking of vulnerable plaque has repeatedly been demonstrated

by statin therapy by Dr. Steve Nissen, Chief of Cardiology at the Cleveland Clinic.

Also, Dr. Dean Ornish’s studies have shown reversal of vulnerable plaque by highly restrictive low-fat diets.)

 

            Although the ultrasound and the CT only detect calcified plaque, that is highly

correlated with vulnerable plaque. Therefore, the presence of calcifications is a major tip-off

that vulnerable plaque is also present. (When vulnerable plaque is present for a long time,

it gradually becomes calcified.  While this narrows the artery, it may have the advantage

of decreasing the chance of plaque rupture.)

 

The Bottom Line

 

            After years of studying the role of the CAC (the Coronary Artery Calcium score

derived from CT), the American Heart Association (AHA) issued a definitive statement in 2007.

 

            "The majority of published studies have reported that the total amount of

coronary calcium predicts coronary disease beyond standard risk factors.”

 

And the AHA’s final conclusion is this.

  

"In intermediate-risk patients, it may be reasonable to measure

 the atherosclerotic burden using EBCT (e-beam CT) to refine

 clinical risk prediction and to select patients for more aggressive

 target values for lipid-lowering therapies." 

 

(Here the AHA is trying to be very conservative in their recommendation,

lest they saddle the nation's health plans with unnecessary expenses.)

 

            I think their conclusion is quite reasonable, if conservative.  If your risk of heart disease

is quite low - a woman under 55 or a man under 45 with no other risk factors,

then the CT may be a waste of money and a needless exposure to x-rays. 
Similarly, if you have multiple risk factors
and are in the highest risk group, then, again,
the test may be a waste of money, since you need aggressive intervention no matter what the test shows. On the other hand,
for the quite large subset in the "intermediate risk" category the test may provide essential new information that can make a huge difference in treatment and life style and outcome.

 

           For those in the intermediate risk category, starting with a carotid ultrasound, as I did, also
seems like a reasonable way to proceed. My guess is that family physicians and internists may be more amenable to ordering that test for you. (I did not discuss the various treadmill tests in this brief presentation. They are an important part in the work up of potentially obstructive coronary disease and particulary in working up chest pain. Unfortunately, every ER physician has seen patients with heart attacks whose treadmill tests were normal.)

 

Health Care Disclaimer: The purpose of this website is simply to provide thoughtful information

of public interest. Do not base any health care decisions on information provided on this website.

Health care decisions depend on your unique situation and can only be evaluated by the providers

actually involved in your care.  While I have tried to provide accurate information on this website,

I cannot guarantee its accuracy or completeness.  All data, information, and opinions are subject

to change without notice. I (Robert Blum) accept no liability for the use or accuracy of the information on this website nor any obligation to keep it current.