Dr. Truc Ly, MD, a Cardiothoracic Surgeon at Baptist Health System in San Antonio, Texas, talks about a new way to treat aortic dissection.
Interview conducted by Ivanhoe Broadcast News in July 2022.
What is an aortic dissection?
LY: An aortic dissection is basically a weakening of the aortic wall, and it causes a tearing of the wall of the aorta.
How do you repair that? What’s the surgery like for that?
LY: It depends on the location of where that tear occurs. There are different components of the aorta. There’s one in the chest and the one in the belly. Of the ones that are in the chest are the ones where I specialize in. There’s a part that’s called the ascending aorta. That’s where it comes out of the heart. Then, when it makes a turn and supplies the blood vessels to the brain and to the arms, we call that the arch. Then, as it’s leaving the chest cavity, it descends through the chest cavity and goes into the belly, and that’s called a descending aorta. To repair the ascending aorta, it depends on which part of the ascending aorta it involves. Does it involve the arch, or does it involve the root? If you have to replace the root in the ascending aorta is called an aortic root replacement. If you’re just doing the ascending part it’s called the ascending aortic replacement. Then, with the arch, it’s called an arch replacement or repair.
What did Sandra Fernandez have done?
LY: She had an aortic root replacement with ascending aortic replacement as well. We took care of the root and the ascending aorta at the same time.
Is that a congenital condition or do you develop that over time?
LY: For her, it was congenital. It was related to the fact that she had a bicuspid aortic valve. But most of the presentation with patients who have aortic aneurysms, they typically present through what we call degenerative disease – meaning as you get older and you have risk factors, you can develop an aneurysm and then that aneurysm then can dissect, so.
When you’re in there doing this surgery, could you walk us through primarily what you’re doing and what kind of tools?
LY: The ascending aorta, in her particular case, a root that was aneurysm as well. We had to replace her valve as well, on top of everything that we did, partly because she had a congenital anomaly in her development of her valve. Instead of having three leaflets, she had two, and it was also leaking. So, she had some regurgitation with that as well. At the time of surgery, we had to open up her chest – what we call a sternotomy. Then, we put her on the heart lung bypass machine. The heart lung bypass machine will do the work of the heart. It’ll drain the body of its blood. It goes through a machine that then filters and oxygenates that blood and returns it to her. What that allows me to do is stop the heart with full support and share her brain, her kidneys, and the rest of her body is getting oxygenated blood. Then, we arrest the heart. And with the heart stopped, we’re able then to replace the components that were diseased. In her case, it was the valve that was replaced, the root that was replaced and the ascending aorta.
Are you making a cut where the diseased portion is? What do you use for the materials to supply it?
LY: It’s a fabric that we replace it with. It’s called gel weave. It’s a cylindrical material that’s been molded to simulate the same type of structure of an area called the valsalva, which is like a little outpouching as it’s coming out of the heart. It creates a balloon shape. After that valsalva, then it narrows down to more of a cylindrical shape. So, this tube graph allows us to replace the diseased part of our aorta. It looks similar to how it should be naturally. The difference with hers was that we were able to have a product that already had a valve that was sewn into it from the manufacturer. It was basically an aortic valve with graft conduit. The valve came with the graft. We cut everything out and then just replaced it.
Is that “the cutting-edge” portion of the procedure?
LY: No, that’s been around for some time. It’s just beforehand, sometimes we had to construct that. But it’s been around on the market for some time. Beforehand, we would have to find what valve she needed and then match it up with the size of the graft and then sew it on the back table prior to implantation.
What is the newest, “cutting-edge” part of the whole procedure?
LY: The way we’ve done it has been tried and true over the last 20 years. Not much has changed with it. How we’ve gotten better results is understanding how to protect the brain during the surgery. It’s what we call antegrade cerebral protection or retrograde cerebral protection. We try to streamline the surgery so that the amount of time where we’re on the heart lung bypass machine or the amount of time that we have what we call hypothermic circulatory arrest is when we call the body down. We stop all blood flow to the rest of the body. So, in that regard, that’s where a lot of the technology has changed over the last several years, is how do we protect the brain better and how do we limit the amount of time that the patient is not receiving blood.
What else do you guys do to protect that brain besides the cooling part?
LY: The majority of the outcomes are going to be related to the duration of the surgery. How quickly can you get through that? There are some anesthesia components, too, as well, like certain types of medication that you can give to protect the brain. Cooling the body down – that protects the brain. Some people will put ice around the head and so forth. But a lot of things have had changes like how cold do we have to go? Then, at the same time as that, we can limit the amount of deep hypothermia. Then, in addition to that, we’re perfusing the brain through other means, too. So, either we’re going through the arm and finding alternate pathways to perfuse the brain or using the venous system and kind of going backwards from the veins to the artery into the brain that way.
What is the most difficult part of this whole condition for the patient? How does it impact their quality of life?
LY: The patients who present with dissection are going to be the ones that have the highest mortality, the least survival. So, 50% of the time, people who present with dissection don’t make it to the hospital. Of the people who do make it to the hospital, only half of those survive. The mortality rate when you look at it total is about 75%. So, the survival for aortic dissection is about 20, 25%. When you talk about what’s the precursor of aneurysms. It’s patients who are at risk for atherosclerotic disease. Family history is very important, too. The prevention of this disease, which is the dissection or the rupture that has almost a 75% mortality rate is what we’re trying to prevent. For our patient, we got to her before the dissection, and we got her in the aneurysmal phase.
What was her precursor or warning that she was sick?
LY: She had a rhythm problem. She presented to her cardiologist where her heart rhythm was abnormal. The cardiologist was able to do the appropriate workup, did an echocardiogram to evaluate the heart, which is an ultrasound of the heart. From there, he was able to detect that she had a bicuspid aortic valve, a two-leaflet valve. Then, with the echo as well, he was able to detect that she had an aneurysm. Then, that led itself to her workup and her detection of an aortal enlarging aneurysm.
Was the original rhythm issue related to the dissection?
LY: No. It led so another thing.
Was she lucky?
LY: Correct. Most of the time, we don’t know what the incidence or the prevalence of aneurysms are, because most of the time, we don’t have a good population study of that. And most of time, patients present, and the story goes that, oh, he died from a heart attack. Well, he could have died from a dissection that caused the heart attack. So, when a lot of people looked at the studies for that, when they did postmortem after the patient passed and they did CAT scans, they found that the arrest that occurred at home that they thought was just a heart attack or the precursor of that was that the patient had a dissection, and that led to the heart attack. So, seven percent of the time that occurs. I think that aneurysms and dissections are very underreported.
For the viewers out there that want to avoid having this happen to them, will they notice anything at all? Will they feel differently if they have it?
LY: Sure. The acute presentation is where they will feel something. That’s where they have chest pain on presentation or stabbing back pain. The prevention is where it’s important. I think that typically for your older patient population in their 60s or 70s and if they have a history of smoking, the recommendation is that you get an ultrasound of your abdomen – that’s to detect an aneurysm in your belly. Those patients have about a seven percent incidence of also having another aneurysm in their body, which is in the chest. And what you can do is you look at risk factors. Primary care physicians need to look at risk factors. Are they smokers? Do they have high blood pressure? Do you have high cholesterol? Those three components lend themselves to development of aneurysms. Do you have a family history of aneurysm? Do you have someone, a first degree relative, that has an aneurysm? Because 20% of time with patients who present with aneurysms, they have another first degree relative that has also an aneurysm or had presented with a dissection or a rupture. The other thing is that if you have connective tissue disorder, too, so if you have patients who have Mark Benoit syndrome or ALS, Daniel’s syndrome, for example, those patients tend to have aneurysms as well. They sometimes present acutely with the dissection. Most of the time, when you have an aneurysm, you won’t present unless you have some form of compressive symptom – meaning that has gotten so big and it’s pushing on something you might feel a fullness in your chest. Or it’s pushing on the esophagus, which is what connects your mouth to your stomach. Patients will say, “I’m having a hard time swallowing and I feel like my food is getting stuck.” But most of the time, that these patients do present is because a catastrophe is about to incur and they’re having symptoms from a tear.
Once Sandra’s done with recovery, is she totally back to normal? No activity restriction or anything?
LY: Correct. There are no activity restrictions with her right now. We still perform surveillance on her. The reason for that is because there’s still other components of the aorta that she developed disease in this area. We want to make sure we can monitor what happens to the rest of the aorta, and follow her.
END OF INTERVIEW
This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.
If you would like more information, please contact:
Natalie Gutierrez
Natalie.gutierrez@baptisthealthsystem.com
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