What You Need to Know About Chronic Total Occlusion

This is Weekly Dose of Wellness brought to you by MemorialCare Health System. Here's Deborah Howell.

Deborah Howell (Host): Welcome to the show. I am Deborah Howell, and today we'll be talking about chronic total occlusion, or CTO, including symptoms, treatment options, and risk factors. Our guest today is Dr. John Bahadorani, a board-certified interventional cardiologist affiliated with Saddleback Memorial Medical Center in Orange County. Welcome back, Dr. Bahadorani. Appreciate having you on the show today.

John Bahadorani, MD: Thank you. Thank you for having me.

Deborah Howell (Host): We'll start from the beginning. What is chronic total occlusion, please?

John Bahadorani, MD: Sure, absolutely. So chronic total occlusions, as they pertain to the coronary system, are defined as 100% occlusion within the coronary artery that have been present for at least three months duration.

Deborah Howell (Host): That's it. Wow. I expected a longer...

John Bahadorani, MD: That's it. Pretty simple.

Deborah Howell (Host): All right. Let's get right into the symptoms associated with CTO.

John Bahadorani, MD: Okay. So, right. The symptoms are very similar to the symptoms someone has when their heart muscles put under strain. So when they exercise, they may be having profound shortness of breath or chest pressure discomfort. Sometimes just minimal activity can bring about these symptoms. They can be associated with nausea, diaphoresis when they do activities. And they can also have a substantial decline in their functional capacity. In addition to that, over time, chronic total occlusions can contribute to a decline in the actual heart function itself, which is known as the ejection fraction.

Deborah Howell (Host): Okay. Okay. Let me back you up just a moment. You said diaphoresis. Maybe you could explain what that is to our audience.

John Bahadorani, MD: Sure. Diaphoresis is just profound kind of cold sweats that one develops with exertion. It is a common symptom of people that are having acute heart attacks.

Deborah Howell (Host): So what's going on in the body to cause those sweats?

John Bahadorani, MD: Right. So basically, when someone exercises, the thing to keep in mind here is that within the heart muscle, there is a concept of supply and demand of oxygen. The supply obviously is the coronary arteries supplying the blood flow which carries the oxygen to the heart muscle and the demand is the actual heart muscle and the requirement of oxygen that it needs in order to function. So as someone increases their activity level the oxygen demand goes up and in normal circumstances that's not a problem. The coronary arteries are well equipped to handle the amount of blood flow that is needed to provide adequate oxygen to the heart muscle. However, when someone has a blockage, in particular in this case, we're talking about 100% blockage, there's an inadequate amount of supply to the heart muscle, thereby creating a territory of heart muscle that is undergoing ischemic insult. And ischemic insult basically means that the oxygen demand of that segment of heart muscle is exceeding the arterial supply.

Deborah Howell (Host): Got it. That was very well put. And now I can really visualize what's going on in the body. What are some of the risk factors for CTO?

John Bahadorani, MD: Right. So the development of CTOs carry the same risk factors as regular coronary artery disease does because basically what it is, it is coronary artery disease that has progressed to a significant level and has formed 100% blockage. So the risk factors are history of smoking, a family history of coronary disease, hypertension, age, gender, diabetes, elevated cholesterol, and these are all the risk factors that one can anticipate in general with coronary artery disease.

Deborah Howell (Host): When you said age, are we talking about 50 plus or?

John Bahadorani, MD: Correct. We're talking about an age of over 45.

Deborah Howell (Host): Okay. Okay. Just when you say age, I was making sure people didn't think it was 80 and over. It's like people need to start looking at these things at an earlier age.

John Bahadorani, MD: One question that I get often is, well, if my artery is 100% blocked, then how is that area of heart muscle not dead? And the important thing to understand here is that development of a chronic total occlusion is a slow-growing process, and it takes a very long time to get to a chronic total occlusion. And what happens is the body oftentimes develops these small hair-like blood vessels that are basically natural bypasses to allow blood flow to form or to allow blood flow to be supplied beyond the chronic total occlusion site. So, right. So there's an area of chronic total occlusion. And then beyond that, there's blood flow being delivered to that blood vessel via these bypass collaterals. But what we know from studies is that these collaterals, while they may be good at rest and at least keeping the heart muscle alive when people aren't doing anything, the moment they start doing activity, the amount of oxygen demand on the heart is much higher than what these collaterals can supply.

Deborah Howell (Host): Now I get it. That is such a visual. You can just see the little tributaries going around, but they aren't big enough to support exercise. Okay.

John Bahadorani, MD: Exactly.

Deborah Howell (Host): So what are some of the treatment options for CTO?

John Bahadorani, MD: So before we get into that, let me back up a little bit. You know, CTOs are present. Our best estimates, based on large contemporary estimates, is that they're prevalent up to about 18% of patients that have coronary disease. And if you look at patients that have had prior open-heart surgery, the prevalence of chronic total occlusion is even as high as 54%. And patients who present with acute heart attacks, 10% of those patients are found to have CTOs. So traditionally, the treatment options have been either medical therapy or coronary artery bypass grafting, and now, with the advent of new techniques, chronic total occlusion, revascularization from a percutaneous approach. If you wanted an exact breakdown of how these things were treated in the past, historically, we can look at the data and say that 44% of CTOs were treated medically, 26% of them were referred for bypass grafting, and only 10% of them were attempted to have the percutaneous revascularization. And that's based on a Canadian CTO registry data.

Deborah Howell (Host): And what is the final one, percutaneous? Can you tell us a little bit more about that?

John Bahadorani, MD: Right. So percutaneous CTO revascularization is what I do as an interventional cardiologist. It is the same technique that we use to deploy stents. But we use much more vigorous, I guess I should say, much heavier weighted wires, as well as other types of catheters and special equipment when we try to cross the area of 100% blockage. And sometimes we even do techniques that are very novel and just specific to CTOs themselves. Once we are able to get across the CTO segment, then we go and proceed with the deploying stents like we would as a normal blockage.

Deborah Howell (Host): Okay. Wow, what a job you have.

John Bahadorani, MD: Yeah, I wouldn't trade it for the world.

Deborah Howell (Host): So in common language, blocked blood vessels, minimally invasive catheter procedures... You're just trying to open these blocked vessels and get the patient to maybe not 100% normalcy, but what is the goal?

John Bahadorani, MD: Right. So there are things that we know. There are things that are still questionable. And there are things that we believe are going to be beneficial. So the things that we know, number one, we know that for sure if we're successful, and I should say that in the hand of a skilled operator, success rates can be as high as 80 to 90%. But if we are successful, then we know for a fact that we can improve a patient's symptoms so that they no longer have angina, which is the chest discomfort with exertion, or have shortness of breath when they exert themselves. And obviously, this is a huge quality of life improvement for that patient.

Deborah Howell (Host): Absolutely.

John Bahadorani, MD: The second thing we know is that we can decrease the need for what they call anti-anginal medication. So earlier when we discussed one of the options being medical therapy, medical therapy consists of beta blockers, nitrates, and some other medications such as Renexa, which help to improve the myocardial efficiency. And these medications obviously have side effects and a lot of patients don't tolerate them. So if we can do procedures that would decrease the need for anti-anginal medications, that's another benefit. We can also decrease the need for open heart surgery if we're successful by doing these revascularization procedures. One of the traditional criticisms when you look at the data of open heart surgery versus stenting procedures historically, we found that one potential area that coronary artery bypass grafting was superior to stenting was that in coronary artery bypass grafting, they got more complete revascularization. And by complete revascularization, I mean that more of the territories that were involved were adequately addressed by bypass grafts. versus people that underwent stenting procedures, oftentimes they would have the, quote, low-hanging fruit treated by having a stenting procedure, and then the CTOs would be left behind for just medical management. And so if we're able to do these CTO procedures and be successful, then we can decrease the need for coronary artery bypass grafting.

Deborah Howell (Host): It's such good work that you do. Such good work.

John Bahadorani, MD: Thank you. Another thing that we know we can improve is the ejection fraction, which is the measure of the function of the left ventricle. So people that have heart failure could potentially benefit by having a CTO opened up so that that area of heart muscle, if it is viable, can return to normal function.

Deborah Howell (Host): So many great new options.

John Bahadorani, MD: Right. And then we can also decrease the risk for arrhythmias because we know that the presence of CTOs, which leads to ischemic territories of heart muscle, can increase the risk of a patient developing arrhythmias, both ventricular and atrial arrhythmias. And then finally, the thing that we do know is that let's say somebody has a CTO and they come back with another heart attack. Well, if the CTO has been treated and they come back with a heart attack involving a different blood vessel, generally the tolerance of the heart attack is better tolerated by the patient because they have improved revascularization versus somebody who has a heart attack involving a different blood vessel and has a CTO on top of that. Those patients generally don't do as well.

Deborah Howell (Host): Some fabulous new options. I wish we had more time, Dr. Bahadorani. We want to thank you so, so much for being on the show today.

John Bahadorani, MD: Sure. Thank you.

Deborah Howell (Host): And for more information or to listen to a podcast of this show, please go to memorialcare.org. That's all for this time. I'm Deborah Howell. Thanks for listening and have yourself a great day.