Friday, August 20, 2010


It has been a cardiologist dream for the last 30 years, to try and see how to identify the " vulnerable plaque ".
Many of us, as we grow older ( >40years ) have coronary artery disease. There are cholesterol plaques accumulating in the walls of our arteries, especially our coronary arteries. However, most of the plaques are stable and therefore silent, and does not cause any untoward incidences. A stable cholesterol plaque, is quite compartible with normal life. When learned this lesson from autopsies done with young soldiers fighting in the Korean war and Vietnam war. These were presumably healthy young soldiers, tough enough for battle. Yet, post-mortem examination of their coronary arteries often revealed that they have significant coronary artery disease, some single vessel, some double vessel and some even triple vessel and left main stem disease. Then again, we often hear ( and I often get asked ), about healthy young men who suddenly collapsed and die ( including medical doctors ). These people have no evidence of heart disease. Upon autopsy, they have established cholesterol accumulation in many of their coronary arteries and one of the plaque had cracked ( or ruptured ), causing coronary thrombosis. The plaques that had ruptured are the vulnerable ones ( the unstable ones ). Medical science had spend a considerable amount of time, money and effort to identify the vulnerable plaque. This business about " you have heart artery blockage, so you are going to die, unless you let me do a balloon angioplasty or bypass surgery, is more a scare tactic then based on facts. Of course, if your plaques are the unstable, vulnerable ones, then you may run the risk of a heart attack ( coronary thrombosis ) and you may die.
The trick therefore is to know, if you plaque ( your coronary artery blockage ) is of the unstable ( vulnerable ) one or the stable ( non-vulnerable ) one.
The July 28th issue of Radiology carried a piece of work in mice, by Dr David Cormode and colleagues at the Mount Sinai School of Medicine, which showed that they can identify the vulnerable plaque in mice, using a multi-colour CT.

We know from earlier work that a plaque becomes vulnerable when it becomes inflamed, and filled with macrophages. High accumulation of LDL-Cholesterol on its own, can cause inflammation. What Dr David and colleagues did was to inject gold tagged high density nanoparticles and inject it into the blood stream. This will get attached to the macrophages in the vessel wall and light up the artery wall. The amount of yellow ( lighting ) when superimposed on the background image with normal contrast, shows up the amount of macrophages accumulated, and therefore the degree of vulnerability. This owkr appears promising.
The trick now is to move for the bench ( animal lab ) into the bedside, to comercialise it and see how it can be applied to the patient. We are probably 10-20 years away from reality.
Interesting idea, workable, I just thought that I will share it with all of you.

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