Melanie Cole, MS (Host): Welcome to the podcast series from the specialists at Penn Medicine. I'm Melanie Cole, and today our discussion focuses on aortic dissection. Joining me is Dr. Kendall Lawrence. She's a Cardiac Surgeon and an Assistant Professor of Cardiac Surgery in the Department of Cardiac Surgery, specializing in aortic surgery at Penn Medicine.

Dr. Lawrence, thank you so much for joining us today. Please give us a little working definition of aortic dissection. Tell us a little bit about the prevalence, what you've seen in the trends, and the causes we know it.

Kendall Lawrence, MD: Sure. Broadly speaking, an aortic dissection occurs when there's a tear in the lining of the aorta. When there's a tear in the lining of the aorta, it can cause a split in the layers of the aorta and create two channels for blood to flow through. When blood flows through what we call the false channel, it can lead to reduced blood flow to different organs and can have catastrophic consequences.

This is a relatively rare phenomenon. It tends to occur in patients that have aneurysms, significant hypertension, or in patients that have connective tissue disorders.

Host: So are there symptoms? What would signal? Because sometimes this kind of thing and aortic issues in the first place are found incidentally anyway. So are there symptoms? How do we know?

Kendall Lawrence, MD: Acute dissections tend to present with rather severe back pain. Whether it's a Type A or a Type B dissection, and I can get into those definitions in a second. They tend to present with severe back pain. It tends to occur between the scapula and it can radiate. What makes dissection sometimes very difficult to diagnose in the emergency department is that they can also have a wide range of symptoms, sometimes leading to misdiagnoses, depending on which of the organ systems is involved.

For example, if the dissection extends down into the coronary artery, patients may present with symptoms that mimic a heart attack. If the dissection extends down into some of the mesenteric blood vessels, patients can present with extreme abdominal pain. If the dissection extends down to the blood vessels affecting the leg, they may present with a cold, malperfused leg.

This wide range of symptomology can make it an extremely tough diagnosis to make.

Host: Wow. Thank you for that. So the general public is probably aware of acute dissection. We've heard about it before, which can absolutely be catastrophic, but there are other types and classifications right, Dr. Lawrence? Tell us about those.

Kendall Lawrence, MD: Broadly speaking, there are two types of aortic dissections. There is a type A aortic dissection and a type B aortic dissection. The type of aortic dissection is defined by where the entry tear in the aorta occurs. If the entry tear occurs in the ascending part of the aorta, it is classified as a Type A dissection.

When those occur, that is a surgical emergency and mandates emergent operation. Type B aortic dissections, in contrast, occur when there is a tear in the aorta that occurs just distal to the subclavian or the most distal arch vessel. Those sometimes require emergent operations, but more frequently can be managed in a subacute setting.

Host: Speak about the approach at the Penn Aorta Center for Acute Dissections. How do you get patients directly to the OR for these life saving interventions? And, then I'd like you to explain chronic dissection, what can be done to address existing tears in the aortic lumen? And we're gonna talk a little bit about aneurysm in a minute. But how do you get people to the OR that quickly?

Kendall Lawrence, MD: So over the past two decades at Penn, we've really built a robust direct to OR program for patients presenting with acute aortic emergencies. We get a call from any number of outside hospitals or outside referrings and they're able to share the CAT scans with us for us to review 24 hours a day over the phone. If we agree with the diagnosis of an acute aortic dissection, we will bring the patient directly from wherever they are to our operating rooms. As soon as the call comes in, we activate an aortic team that's composed of an aortic surgeon, a cardiac anesthesiologist with a specialty in aortic medicine, It also activates our perfusionists and our critical care providers, as well as our nurses.

When the patient arrives to the operating room, we are all waiting to meet that patient. We confirm the diagnosis when they arrive. We put in monitoring lines for safety. And if we agree that the patient does in fact have a type A dissection, we proceed directly to operating. We know that with type A aortic dissections, the longer we wait to fix the problem, the more likely the patient is to not survive.

Therefore, we think that getting the patient to the operating room directly, not wasting any time, confirming the diagnosis and getting them on to bypass to remove the entry tear is the key to our excellent survival outcomes. You also asked about chronic dissections. A lot of times when patients come in with type A dissections, we cut out and repair the entry tear in the ascending aorta and aortic arch, but they can be left with residual dissections in the descending thoracic aorta.

We know about 10 to 15 percent of these patients will ultimately require some sort of intervention on their distal aorta over their lifetime. We enter these patients into active surveillance programs that involve regular CT screenings and meeting with our aortic team. We know that once the aorta is dissected, its wall integrity is never the same and these people can become prone to developing aneurysmal degeneration of their chronic dissections.

When this occurs in the descending thoracic aorta, we are oftentimes able to deal with this in an elective setting and we can use endovascular technologies such as TVAR and some newer branch devices in order to repair these chronic dissections frequently.

Host: What an exciting time in your field, Dr. Lawrence, and the leading risk factor for dissection is ascending thoracic aortic aneurysm. Do we know what causes these type of aneurysms? And if so, and this is something that really many people have questions about is general screening mechanisms. Do they exist to identify individuals at risk?

Kendall Lawrence, MD: We know that patients that present with thoracic aortic aneurysms, about 20 to 30 percent of those patients are going to have a genetic cause to their aneurysms. Unlike aneurysms that occur in the belly, these are less often due to lifestyle factors, although hypertension can be a risk for the development of ascending aortic aneurysms.

At Penn, we have a robust genetic medicine program, and for patients that present particularly at a young age with no other identifiable risk factors and a family history of aortic aneurysms, we frequently offer genetic testing to them if they are interested. We know, too, that there are a few other conditions that can predispose patients to developing aneurysms, such as the presence of a bicuspid valve, or connective tissue disorders.

In those patients, we enter them into an active surveillance program to lead to early diagnosis of their aneurysms. Finally, in patients who are family members of patients who have had aortic dissections, we also enter them into a surveillance program in order to identify the presence of aneurysms in family members at an early rate.

Host: As we're talking about identifying family members and at risk patients, are there treatments available to slow or reverse the development of these aneurysm and then reduce the risk of dissection? What's exciting in your field?

Kendall Lawrence, MD: So once an aneurysm develops, there's nothing that can be done to reduce the size of the aneurysm. We do know that with excellent blood pressure control, a lot of these aneurysms can be stable for years, even decades. There are some medications such as blood pressure medications in the ARB class that have been used to reduce the rate of aortic growth, particularly in patients with Marfan's Disease.

Sometimes these aneurysms though can be unpredictable and that's why we really advocate for patients once the diagnosis of aneurysm has been made to enter into active surveillance programs with us.

Host: Dr. Lawrence, this is such an interesting discussion, as we get ready to wrap up, I'd like you to tell us about the Penn Aorta Center for Acute and Chronic Dissection. Tell us about your team, the multidisciplinary approach that is necessary for these patients, and if someone wishes to refer to the Penn Aorta Center, who would they contact?

Kendall Lawrence, MD: Sure. We are one of the busiest aortic centers in the United States. I think one of the things that really makes us special is our amazing multidisciplinary relationship with vascular surgery. Our clinics are run with vascular surgeons and that allows us to see every patient with complex aortic disease together, so that we can ultimately come up with the best treatment plan for that patient, whether it's an open repair, an endovascular repair, or a staged operation together.

 If patients want to refer to the Penn Aortic Center, there's a couple different ways that they can do it. For internal referrals within the Penn system, you can place a consult order to Cardiac Surgery and choose the Penn Aortic Center in EPIC. For external referrals, there is a phone number to the HVC call center, and you can specify that you would like to be directed to the Penn Aortic Center.

That phone number is 215-615-4949. Additionally, we also have an email address, which is open for patients or referrings to use. It is PennAortaCenter@ pennmedicine.upenn.edu, and this is checked regularly by one of our nurse practitioner with a specialty in aortic medicine.

Host: Thank you so much, Dr. Lawrence, for joining us today and sharing your incredible expertise. And to refer your patient to Dr. Lawrence at Penn Medicine, you can always call our 24/7 provider only line at 877-937-PENN, or you can submit your referral via our secure online referral form by visiting our website at pennmedicine.org/referyourpatient.

That concludes this episode from the specialists at Penn Medicine. I'm Melanie Cole. Thanks so much for joining us today.