Cardiologists use many successful ways to diagnose heart problems – from treadmill stress tests and ultrasound to cardiac catheterizations and angiograms. Yet, McLeod Cardiologist says they are still in search of a successful way to look inside an artery’s walls without making an incision. Dr. Pande calls this the “holy grail” of cardiology:
Here’s a transcript of Dr. Pande’s comments:
We have tests to see the muscles of the heart. With the echocardiogram we can see the heart muscle. When a person has a heart attack, the heart muscle gets damaged. The normal thickness of the heart is replaced by fibrous (leathery) tissue.
Arteries are the tubes outside the heart, giving blood to the heart. The heart is a simple muscle. It needs nutrition from the blood to do its work, pumping blood throughout the body.
We use angiography to look inside the blood vessels of the heart and see the blood flow in there. But the problem exists in the wall of the blood vessel, not inside the tube. Many times the cholesterol is in the wall of the artery. It’s like termites in the wall of a house. You have no way of seeing the termites with your eyes, unless you cut through the wall.
So, even if your artery has a 30% or 40% blockage, you don’t know how bad the problem is in the wall of the blood vessel, because the angiography test only shows you inside the tube.
Even today, there is no good screening mechanism to tell us the condition of the walls of your arteries. And that’s the “holy grail of cardiology.? We need a non-invasive (no incision or cut) test to tell us what’s happening in the walls of the artery.
As a cardiologist, I don’t have a test to be able to tell you that. There is no non-invasive test that can look at the walls and confirm that the lining is nice and thin and, therefore, you have zero chance of a heart attack.
There is a special CT scan that, when it came along, we thought it was a natural replacement to angiography. But there are several problems with non-invasive CT scan. First, you have to be relatively small (less than 200 or 250 pounds) to get good images. Second, the heart is the only organ we have that is contracting and twisting as it works. And the blood vessels are only 3 millimeters (a smaller around than a pencil eraser). So taking pictures is difficult.
And we will see plague (a combination of cholesterol, fat, calcium and other substances in the blood) – a whole bunch of plaque. But we can’t tell the significance of the plaque we see. Everyone has plaque in their arteries. But which one will rupture? And which will stay stable not causing any problems for the foreseeable future? That is the one answer we do not have.
So currently the search is on to be able to noninvasively detect “Vulnerable Plaque”, that is plaque which potentially can rupture in the near future and lead to a heart attack. A stable plaque has more fibrous tissue and less lipids inside it, with more signs of healing. Vulnerable Plaque has a thin fibrous cap, a whole lot more lipids, with active signs of inflammation. There are investigations about thermal imaging which are at research stage, but still not approved for general use.
The current treatment is aggressive risk factor modification, which includes antiplatelet agents like aspirin and Plavix, aggressive reduction of cholesterol therapy, and aggressive control of diabetes and blood pressure, and most importantly complete cessation of tobacco products.
ACTION YOU CAN TAKE
Dr. Pande says that until a non-invasive test is developed to look inside the artery’s wall the best thing a person can do is reduce their risk factors: