One of the other things

One of the other things it can do for you is tell you if there are other vessels involved. In other words, did this gentleman have single vessel disease? He’s infarcted what he’s going to infarct. End of story. Now we know he has coronary disease. Let’s work on his risk factors but we don’t have to be incredibly aggressive about looking for another stenosis to angioplasty or perhaps bypass. Versus does this man have three vessel disease and he’s only infarcted one of his territories and we need to be very aggressive.
It can also tell you the size of the infarct. Obviously the larger the infarct, the more at risk the patient is. The more proximal the stenosis is in the vessel, the larger the infarct will be and, again, if ischemia is present, you may want intervention.

Consider in this patient population also doing a thallium scan. The times you do a thallium scan is when you’re looking for something called viable myocardium. Basically, viable myocardium are cells that have been damaged by the hypoxia but have retained their cell wall integrity and enough of the myocardial cell functions that if you resupply or reestablish the oxygen supply they will completely recover and start to contract normally again. Typically the patient has a known stenosis, a contractility abnormality – there’s hypo or akinesia or perhaps dyskinesia – in that same territory. Usually they have a low ejection fraction and that is somebody who you might want to reestablish the blood flow to that area of infarct to see if you can salvage that myocardium. This is what PET scanning is really very good for and if you have that available to you I would strongly consider it because it is more specific as well as more sensitive than a thallium scan.

Now I forgot to discuss the efficacy of current therapy. Here’s something that you all would be very interested in. Let’s not forget that this thing called “silent ischemia” or “silent infarct” is real. A lot of patients do not have the typical chest pain syndrome and you cannot use symptoms alone in order to monitor the efficacy of therapy. Again, really what you are looking for is extent and severity of ischemia on a current medical regimen. This is one of those times when you definitely don’t need to change the patient’s heart medications prior to getting the study going and, if you can, try to go with an exercise treadmill type stress test. That way you know just how far the patient can go and just how protective those drugs are that you have them on.

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