Tablet therapy, PCI (ballooning) and Heart Bypass Surgery for Coronary Artery Disease.

So, we spoke about coronary artery disease and that starts off with cholesterol sitting on the lining of the artery. Once that cholesterol has been there for a long time, it calcifies, it becomes hardened. And calcified plaque or hardened plaque in the heart arteries, can see on a CT scan, as well as the non-calcified cholesterol soft plaque, as we described it when we're doing CT scans of the heart arteries. Now, if you have either soft or calcified plaque in the heart arteries, and if that's causing a significant narrowing of the artery, then that can cause symptoms. And the threshold that we tend to assign to the narrowing is 70%. So if the artery is over 70% narrowed, then we know that there's a significant narrowing in the heart artery and that can lead to angina or symptoms. So at that level, once it's 70% or above, you would think about treatment in the form of stents perhaps or bypass surgery. Now stents and bypass surgery are really only recommended when the patient has symptoms that are not controlled with medical therapy. So what medical therapy can we give to people with coronary artery disease? The first thing that all patients with coronary artery disease should get is a statin because statins strengthen the lining of the artery. They help stabilize the cholesterol that's there. So if you have a cholesterol buildup within the lining of the artery and if the surface of that is very unstable, it's more likely that clot or platelets can stick on there, form a clot and block a heart artery and that leads to a heart attack. So what we don't want is for the lining of the plaque, the cholesterol plaque that's in there, to be very unhealthy and again statins help stabilize that plaque making it less likely for you to get a heart attack. So statins stabilize the plaque, they improve the overall lining of the artery and of course they reduce your overall cholesterol level itself and you know there are various statistics and measurements suggesting that if if you reduce the cholesterol by even one millimole per liter that you're impacting significantly on reducing the number of heart attacks, et cetera. So that is the first and foremost thing for treatment of coronary artery disease, getting your cholesterol controlled and improving lining with statin therapy. Beyond statin therapy, there are other agents to help lower the cholesterol, but statins are by far and away the best known for that at the moment. We do have other options that are growing and those are injectable agents, but again they're not in sort of widespread use at the moment and the mainstay is with statin therapy. Beyond that, when you're talking about narrowings that are severe, so over 70%, really, as I said, the treatment modality is determined by the symptoms. and we can control angina-type symptoms that you would get from a severe narrowing in an artery with anti-angina medications. So you can imagine angina is there because you have a severe narrowing, so you have a supply and demand mismatch. The heart muscle wants more oxygen via the blood, and it's not getting that because there is a severe narrowing in the artery. And we can help reduce the workload of the heart muscle by slowing it down, by getting beta blockers. You can also use calcium channel blockers as well and other drugs, a drug called ranolazine, as well as other types of medications, nitrates, et cetera, that help relax arteries. And these drugs can help relieve the symptoms of angina, but don't, of course, affect the actual narrowing itself. So dealing with the narrowing itself with the statins and whatever else, but treating the symptoms of angina It's usually with beta blockers, calcium channel blockers like amlodipine, nitrates like isosorbic mononitrate, or drugs like ranolazine. And then once the patient still has symptoms despite antanginal therapy, you then go on to think about stents. So stents can, of course, they go into that narrowing. So if you have the lumen of an artery, so you think about a tube, and if that tube has a 70% narrowing in it, you have a small area of blood supply that is then going to the muscle. So you can squash that plaque to the side, squash that cholesterol to the side with a stent. A stent is like a metal strut or a polymer strut that keeps the artery nice and open. So you insert a wire in through that narrowing and there's a small balloon over that wire with a stent over that. And so you expand the balloon, which squashes and opens the stent and squashes the cholesterol to the side. So that's a sense that you could use to alleviate a focal narrowing in an artery. Especially in diabetic patients, it may not be just a focal narrowing. It may be diffuse disease along the length of the vessel. And if that's the case, then a bypass may be better. So a bypass is exactly as it says, it bypasses the area of narrowing. So if you have a severe narrowing at the hilt or at the start of an artery, and then further narrowings along the artery, find an area of the artery where you don't have any narrowings and you bypass an artery over that area and plug it in where there is no more disease or less disease and the origin of that artery is then plugged into your aorta which is the main artery that comes off the top of the heart. So that is a bypass where you literally bypass the area of severe narrowings. And those are your main options are medical therapy to treat angina to begin with but in those patients who have symptoms despite that, or potentially in people with triple vessel coronary disease who are diabetic, you would then think about going straight on to bypass surgery.