Will CV Biomarkers Cull the Middle-Risk People?
Will CV Biomarkers Cull the Middle-Risk People?
Dr. Black: That brings us to something else that puzzles me, which is that we are always trying to pick out the high-risk individuals. We thought we knew how to do that. Then along comes high-sensitivity-C reactive protein (hs-CRP), lipoprotein(a), and other biomarkers. What do you think about the value of those in the workup of a patient with high lipids, or even somebody who doesn't and is around that age range?
Dr. Weintraub: I do not worship at the altar of CRP. I know there are a lot of people who feel very strongly about it. For those who are curious, there was a recent article in the Journal of the American College of Cardiology by a well-respected group of people from different centers, who did a very serious, thought-out evaluation of CRP. In spite of the strengths of CRP, which have been clearly there in some population trials, they came to the conclusion that it really was not fulfilling the niche that it would like to have.
Dr. Black: What use would that be?
Dr. Weintraub: Being the silver bullet for identifying cardiac risk. You and I know that we were told by the people from Brigham, and particularly by Dr. Ridker -- a very smart guy -- that CRP was a more important variable than LDL and other things. It got to the point a few years ago where people would be referred to the office for CRP consults. Their LDL would be 90 and they had no other comorbidities, but their CRP was 4 and the doctor was ready to do a full cardiac workup because he or she was convinced that they were headed for the critical care unit.
And clearly that is not the case. Imagine, if you will, Henry, a 75-year-old hypertensive, dyslipidemic, smoking, obese, diabetic person with a CRP of 1. Are you not going to treat him? Or, conversely, a 22-year-old woman who is a cheerleader and whose family history [shows that they] live into their 90's, and she doesn't have an ounce of fat and is on the StairMaster 6 days a week -- her CRP is 3. Are you going to treat her?
Dr. Black: Certainly not.
Dr. Weintraub: There you go.
Dr. Black: But CRP may, in some instances, pick out the high-risk individual from the medium-risk individual from the low-risk individual.
Dr. Weintraub: We get into the point of all of these tests, in which, clearly, the 2 ends of the dumbbell don't need any help. They are the very low-risk, and you probably are not going to reassign, and the very high risk, where it is unlikely that you are going to reassign.
Dr. Black: Knowing that you have a high or low hs-CRP is not going to change your approach...
Dr. Weintraub: In those 2 groups.
Dr. Black: Right.
Dr. Weintraub: So then you get the middle-risk individuals, where there is clearly the largest number of patients, in which you have image device users and makers and hosts of other companies looking to identify the trilogy or the quadrilogy -- if that's a word -- of the biomarkers.
Dr. Black: The thing about the images, though, is that none of them have panned out.
Dr. Weintraub: That's an interesting pun there, Henry.
Dr. Black: They are expensive to do. The operators have to be very good. The interpreters have to be very good, as opposed to hs-CRP, which is a blood test, and you can leave that sitting on the bench for a day and you still get the right number.
Dr. Weintraub: The problem is that it varies during the course of the day. It varies upon what you ate a few hours before. It varies upon whether you have a cold.
Dr. Black: Or gingivitis.
Dr. Weintraub: Or gingivitis, or a urinary infection, or if you have sprained an ankle. So aside from that, it is a very useful tool.
Dr. Black: So you make sure you don't do it in those people.
Dr. Weintraub: But what you are doing is excluding a large number of people who would be appropriate candidates for it.
How Useful Is C-Reactive Protein?
Dr. Black: That brings us to something else that puzzles me, which is that we are always trying to pick out the high-risk individuals. We thought we knew how to do that. Then along comes high-sensitivity-C reactive protein (hs-CRP), lipoprotein(a), and other biomarkers. What do you think about the value of those in the workup of a patient with high lipids, or even somebody who doesn't and is around that age range?
Dr. Weintraub: I do not worship at the altar of CRP. I know there are a lot of people who feel very strongly about it. For those who are curious, there was a recent article in the Journal of the American College of Cardiology by a well-respected group of people from different centers, who did a very serious, thought-out evaluation of CRP. In spite of the strengths of CRP, which have been clearly there in some population trials, they came to the conclusion that it really was not fulfilling the niche that it would like to have.
Dr. Black: What use would that be?
Dr. Weintraub: Being the silver bullet for identifying cardiac risk. You and I know that we were told by the people from Brigham, and particularly by Dr. Ridker -- a very smart guy -- that CRP was a more important variable than LDL and other things. It got to the point a few years ago where people would be referred to the office for CRP consults. Their LDL would be 90 and they had no other comorbidities, but their CRP was 4 and the doctor was ready to do a full cardiac workup because he or she was convinced that they were headed for the critical care unit.
And clearly that is not the case. Imagine, if you will, Henry, a 75-year-old hypertensive, dyslipidemic, smoking, obese, diabetic person with a CRP of 1. Are you not going to treat him? Or, conversely, a 22-year-old woman who is a cheerleader and whose family history [shows that they] live into their 90's, and she doesn't have an ounce of fat and is on the StairMaster 6 days a week -- her CRP is 3. Are you going to treat her?
Dr. Black: Certainly not.
Dr. Weintraub: There you go.
Dr. Black: But CRP may, in some instances, pick out the high-risk individual from the medium-risk individual from the low-risk individual.
Dr. Weintraub: We get into the point of all of these tests, in which, clearly, the 2 ends of the dumbbell don't need any help. They are the very low-risk, and you probably are not going to reassign, and the very high risk, where it is unlikely that you are going to reassign.
Dr. Black: Knowing that you have a high or low hs-CRP is not going to change your approach...
Dr. Weintraub: In those 2 groups.
Dr. Black: Right.
Dr. Weintraub: So then you get the middle-risk individuals, where there is clearly the largest number of patients, in which you have image device users and makers and hosts of other companies looking to identify the trilogy or the quadrilogy -- if that's a word -- of the biomarkers.
Dr. Black: The thing about the images, though, is that none of them have panned out.
Dr. Weintraub: That's an interesting pun there, Henry.
Dr. Black: They are expensive to do. The operators have to be very good. The interpreters have to be very good, as opposed to hs-CRP, which is a blood test, and you can leave that sitting on the bench for a day and you still get the right number.
Dr. Weintraub: The problem is that it varies during the course of the day. It varies upon what you ate a few hours before. It varies upon whether you have a cold.
Dr. Black: Or gingivitis.
Dr. Weintraub: Or gingivitis, or a urinary infection, or if you have sprained an ankle. So aside from that, it is a very useful tool.
Dr. Black: So you make sure you don't do it in those people.
Dr. Weintraub: But what you are doing is excluding a large number of people who would be appropriate candidates for it.
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