Let's play a game.
I'm going to list some lipid patterns and you tell me whether or not the person with these values has heart disease.
Total cholesterol 150 mg/dl
LDL cholesterol 75 mg/dl
HDL 50 mg/dl
Triglycerides 125 mg/dl
Total cholesterol 300 mg/dl
LDL cholesterol 200 mg/dl
HDL cholesterol 35 mg/dl
Total cholesterol 300 mg/dl
LDL cholesterol 100 mg/dl
HDL cholesterol 25 mg/dl
Triglycerides 875 mg/dl
Let's say that any one of these profiles is yours . Should you be getting your affairs in order, preparing for your cardiac catastrophe? Should you demand a stress test from your doctor, hoping that it will shed some light on your dilemma? Should you go ahead and go to the all-you-can-eat rib restaurant, content that you will be attending your granddaughger's wedding in 2020 in full health?
If you can tell, you're a lot better at this than I am.
I provide consultation to other physicians and patients on complex hyperlipidemias in my area. In other words, if someone has a difficulty to manage lipid disorder, the doctor sends the patient to me.
Managing these wildly variable values is the easy part. Deciding whether or not heart disease is concealed within the patient . . . well, that's the hard part.
Let's take it a step further: Suppose all three profiles also have 50% of all LDL particles as the abnormal small particles. And they all have a lipoprotein(a) level of 50 mg/dl, an abnormally high level.
How about now: Can you tell whether any or all of these people have hidden heart disease?
What if they are 20 years old? Does that make a difference?
What if they are all females over 65 years--how about now?
If the only tool you have to divine the presence of hidden heart disease is a lipid panel, or even a lipoprotein panel, then the best you can manage is to hazard a guess based on statistical probability. You also assume that this "snapshot" represents the sorts of values someone has had for their entire lives. You cannot factor in the fact that the first person gained 60 lbs in the last three years since completing menopause. You can't factor in that patient 2 smoked two packs of cigarettes a day for 25 years, but quit 10 years ago.
It's also foolhardy to believe that every known cause of heart disease is currently identifiable and revealed by modern-day blood testing.
A heart scan is simply a means to quantify the sum-total of risk factors--causes--that have exerted an effect up until the moment of your scan. It will reveal the quantity of coronary atherosclerotic plaque present, regardless of whether you stopped smoking 20 years ago or lost 30 lbs last year.
For these reasons, nothing can replace the value of quantifying plaque: not cholesterol, not the Framingham risk calculation, not measures of small LDL or lipoprotein(a), not the presence or absence of symptoms. In 2008, the method of choice for measuring plaque remains a CT heart scan. Perhaps in 10 years it will be some other method.
As always, let me remind Heart Scan Blog viewers that I make this point NOT to sell heart scans, which I have no reason whatsoever to do. I say this because we require a tool to track this potentially fatal disease. We require a yardstick for tracking progression or regression. The only tool that suits these purposes in 2008 is a CT heart scan.