In this episode, Andrew Perry, MD, talks with Amber Khanna, MD, of the University of Colorado in Aurora, about some of the "simple" congenital heart defects. They discuss atrial septal defects (ASDs) and ventricular septal defects (VSDs) -- which diagnostic tests are useful, how to evaluate these defects, and indications for closure.
A transcript of the podcast follows:
Perry: Hey, everyone. It's Andrew. I hope you enjoyed the last episode about the hypertension guideline update with Dr. Eugene Yang. In today's episode, I'm visiting with Dr. Amber Khanna from the University of Colorado. She is a specialist in adult congenital heart disease. For anyone who doesn't practice and research within that space, I feel like this topic can be overwhelming, and when you see these patients, you just worry and fret that you're going to do the wrong thing and make sure you don't do them any harm. We talked about some fairly simple lesions, ASDs and VSDs. I think it was a really great discussion and she elaborates a lot on her practice style and the indications for closure and much more. I think you'll really enjoy it.
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Khanna: My name is Amber Khanna. I'm an associate professor at the University of Colorado School of Medicine.
Perry: Great! Thank you for meeting with me today, Dr. Khanna. One of your areas of expertise is adult congenital heart disease, right?
Khanna: That is right.
Perry: How long have you been doing that?
Khanna: I did my fellowship in adult cardiology and adult congenital heart disease, and I finished that in 2011, so just over 8 years.
Perry: So today, I want to talk with you about two very common conditions of adult congenital heart disease: ASDs and VSDs. We'll jump right into it with the first case. We have a 45-year-old woman and she's referred to you for evaluation of new paroxysmal atrial fibrillation. On exam, she has a fixed S2 with a 1 out of 6 diastolic murmur at the left sternal border. Her EKG shows atrial fibrillation with a right axis deviation and an incomplete right bundle branch block. The transthoracic echo demonstrates a secundum ASD with a severely dilated right atrium and a moderately dilated right ventricle. My first question about this is what additional diagnostics should be performed for her?
Khanna: It's a good question because there's not a clear answer. If you look at the adult congenital heart disease guidelines, it lists what diagnostics can be performed, but it doesn't really narrow it down or tell you which ones should be performed. There are things you need to accomplish with the workup. The first step is to decide, "Are we sure about the diagnosis? Is it related to secundum ASD? Are we missing any other lesions?" About 10% of secundum ASDs are associated with partial anomalous pulmonary venous return, so you need to do testing to make sure the patient does not have that, or if they do, it changes your management.
The next step is to confirm the diagnoses. The next step is also to decide if the patient can and should undergo closure. You need to somehow make sure that closing this atrial septal defect will be safe. My next step is usually a cardiac MRI. A cardiac MRI gives me anatomic detail of the ASD and can confirm if it's a secundum or another type of ASD. It will confirm the pulmonary veins and tell me if there is or is not partial anomalous pulmonary venous return. It will show me the proximal coronary arteries. This is not in the guidelines, but this is driven by my N-of-1 patient who I sent for a percutaneous closure and missed the anomalous right coronary artery from the left coronary cusp. I don't think this is a common anomaly in ASDs, but it is one that I will not personally miss again.
Perry: Gotcha, I see.
Khanna: It's nice to know that they're coming off from the right cusp before you pursue an intervention. It will give you a Qp/Qs. So we all know what Q is.
Perry: Q is flow.
Khanna: Q is flow, right? Because we ordered a VQ scan. We know if the V stands for ventilation, the Q must stand for flow. A Qp/Qs is the flow through the pulmonary vasculature compared to the flow through the systemic vasculature. Normal Qp/Qs should be exactly 1.1. There should be exactly the same amount of blood flow going to the lungs as going to the body. If you have a left-to-right flow, meaning you now have more blood flow in your right circulation, in your pulmonary circulation, you have a Qp/Qs that's greater than 1. You have more blood flow going to your lungs than your body.
Perry: Surely there's some amount of error for this 1, give or take so many few.
Khanna: There is, but it's actually pretty minimal. Probably 5% or less.
Perry: Really? Okay.
Khanna: Most of the time when the cath lab does a very careful Qp/Qs calculation, it's usually between 0.95 and 1.05. It's pretty good and the MRI is actually pretty good, too. If I start to see a Qp/Qs that's more than 10% away from 1, then I believe it and I think that there may actually be a shunt there.
Perry: I see. Kind of going back. We need to confirm the diagnosis. For you, that involves a cardiac MRI, so you're going to get anatomy, maybe a clearer picture of this ASD and where it is exactly within the septum, the interatrial septum. Additionally with that MRI, you're going to obtain more information about anomalous pulmonary venous return because that sounds like it's a very common condition associated with ASDs.
Khanna: Common enough. With secundum ASDs, it's 10% to 15%, so not a guarantee. Probably not. Most patients don't have it, but it's a high enough percent that you need to look for it. For pulmonary veins, it's very rare that you can see that kind of detail on an adult echocardiogram. Some pediatric echocardiograms you can see all of the pulmonary veins. On a TEE, you can see and count how many veins are draining into the left atrium, but you don't see the venous anatomy enough to know if maybe there's one more pulmonary vein that's draining high in the SVC. I don't think a TEE is reliable enough to rule out anomalous veins.
Perry: Once we've confirmed the diagnosis and screened for this other condition, then getting a Qp/Qs, which can be done through the MRI or through a cath, this is then to be looking for indications for closure.
Khanna: Right. Just because you have a hole in your heart doesn't mean you need to have the hole in your heart closed. We have lots of patients walking around with holes and they do just fine. There is a question about who should have their ASD closed.
Perry: Exactly. Let's go right there.
Khanna: So if it's causing problems, you should have it closed. The kinds of problems it can cause, if we think it's really causing symptoms, it should be closed. But symptoms are very hard to sort out, because I see a lot of patients who come in with shortness of breath. They've had the hole their whole life. Why is it now causing shortness of breath? Is it really the hole that's causing the shortness of breath? Trying to piece that out is very difficult. We ended up using a lot of other evidence. If the hole is big enough and the Qp/Qs is high enough that the right heart is now dilated, then we should probably close the hole. That's sort of the easy answer. If the right heart is starting to show signs of stress from this hole in the heart, we should close the hole in the heart.
Atrial arrhythmias are a tricky one. In general, if somebody has an atrial arrhythmia, it implies that there's stress in the heart. If you close the hole, that won't change the long-term risk of recurrence of atrial fibrillation. We know that if we close ASDs in young people, we prevent the risk of atrial fibrillation. If somebody has already developed atrial fibrillation, we can't go back and fix that. If somebody has a large ASD and they reach the age of 40 or so and it hasn't been closed, they've already assumed that risk of atrial fibrillation and it probably isn't as helpful going down the line to close it for the sole purpose of preventing atrial fibrillation.
Perry: Interesting. It's like there's this concept that you're having a lot of left to right flow in your heart, and then at some point, you've crossed a threshold at which you're almost guaranteed to develop atrial fibrillation or maybe not guaranteed, but your modifiable risk of developing atrial fibrillation is no longer modifiable.
Khanna: Correct.
Perry: We reduce this hole to modify that risk.
Khanna: Yeah, you have assumed that risk. It's now there. Either it's going to happen or it's not going to happen, but closing the ASD probably won't make that much of a difference.
Perry: Interesting. For our patient, she's 45 and having atrial fibrillation. At this point, we're not going to fix her atrial fibrillation just by closing it.
Khanna: Absolutely not.
Perry: But she has a moderately dilated right ventricle. That may be an indication to pursue.
Khanna: She probably has a high enough Qp/Qs. Some people use 1.5 as a cutoff, so 50% more blood flow going to the lungs and the body. They go together, so if you have a high Qp/Qs, you should see the right side start to dilate. If the right side is dilated, you should have a high Qp/Qs. They go hand in hand up until you get significant pulmonary hypertension, which I think we'll talk about in a few minutes.
Perry: Okay.
Khanna: They should go together and we always pause if we see one of them out of proportion to the other one. A really big RV and a Qp/Qs that's not that high should make you think about what's going on. The same thing if you have a really high Qp/Qs and the RV is normal size, you have to just think about how could that have happened. I think she needs that evaluation. Given her age, she probably needs a cardiac catheterization to actually measure the pressures in her lungs. Sometimes young people, so in kids, they don't always do it. Then in some of our young adults where we have a clear TR and we can estimate the pulmonary pressures fairly well on that, the MRI is confirming a high Qp/Qs and the patient has normal oxygenation at rest and with exercise -- if they meet all of those criteria, we won't always do a diagnostic cardiac cath before closure.
Perry: Got it. Understood, because we have reliable information from the echo.
Khanna: Yeah. The combination of the echo, the oxygen saturation, and the MRI, we can dare to feel comfortable that we're not missing severe pulmonary hypertension.
Perry: Let's go down this road of say she does have concomitant pulmonary hypertension. This is probably a common scenario particularly in younger women, having an ASD of some size, then also showing up with pulmonary hypertension and their right ventricle is dilated. How do you tease out the differences? Maybe their Qp/Qs is kind of borderline like 1.4, 1.5, right there on the cusp and how do you know which way this person shakes out?
Khanna: It ends up being very tricky. The first thing you need is a very meticulous, careful cardiac catheterization. This isn't the interventional cardiologist that can throw a stent in in 20 minutes, grabbing two stats and getting out of there and trying to do the calculations. This is measuring saturations in the SVC, in the IVC, in the multiple points within the right atrium, right ventricle, pulmonary artery. It's crossing the septum, but getting true pulmonary vein saturations, getting arterial saturations. It is a meticulous cardiac catheterization. If we go back to our basic hemodynamics, cardiac hemodynamics a bit, the more flow you have moving through a system, the higher the pressure is going to be. We don't really care what the pressure in the lungs is. We care about the resistance in the lungs.
But you can have a scenario where the pressure is high, the flow is high, and your resistance is actually pretty normal. In that case, please close the hole. As soon as you close the ASD, you drop the flow and the pulmonary pressures will drop nicely. That is not Eisenmenger syndrome. That is just normal hemodynamics and something we see. You calculate a very high Qp/Qs, 3, maybe even 4. You have 10 liters of flow going through the lungs. Yeah. The pressure is going to be there, but your resistance when you go through all of the math again, the resistance can come out to be very reassuring, and these patients do very well with ASD closure.
Perry: I guess I'm surprised. So presumably these people are living with an ASD for decades and having high flows for decades.
Khanna: Right.
Perry: If there's no pulmonary vascular remodeling in that time period to then create resistance, I guess that seems odd to me that can actually be the case.
Khanna: Right. It happens more often in men, so women are more likely to have the pulmonary vascular remodeling and the increase in the resistance. There's probably some controversy if true Eisenmenger syndrome exists with just ASDs. Some people will argue that every time you see an ASD with true, fixed, increased resistance, fixed pulmonary hypertension, precapillary pulmonary hypertension, everything looks like Eisenmenger syndrome. If the only [...] is an ASD, maybe you found the person that has primary PH and an ASD. It just doesn't happen that often. Some moderate pulmonary hypertension happens, but the true Eisenmenger syndrome does not happen very often. I haven't done the advanced statistics on the prevalence of primary pulmonary hypertension and the prevalence of ASDs, but you would expect that those two conditions, we see both of them all the time in clinic, in our referral centers, but we see them. It certainly makes sense that it could happen together on occasion.
Perry: That would just be exceedingly rare to have that happen.
Khanna: Right. The pulmonary hypertension, most people think it's at least a two-hit hypothesis. You need increased flow and something else. We certainly see pulmonary hypertension in our high-pressure, high-flow shunts, such as VSDs and PDAs. When you have those, it's not just flow. When you're above the tricuspid valve, you only have flow. You don't have extra pressure pushing the blood through. A big ASD and a big PDA has a lot of flow and a lot of pressure and will almost always cause Eisenmenger syndrome if not repaired.
Perry: Got it.
Khanna: ASD you can live with your entire life and have a high Qp/Qs and not necessarily develop the pulmonary hypertension. Something else.
Perry: Maybe the pressure difference. We're going to have the flow, but the difference here is now the pressure difference.
Khanna: Now we just have flow. If you take somebody who just has flow and you give them either some degree of genetic predisposition or another hit on the lungs -- maybe they have some other cause of pulmonary hypertension, they took some medicines or they did drugs -- this thing that was the second hit, and that was enough with the shunt to cause it.
Perry: Now, let's come back to our case a little bit. We discussed about some of these other issues and possibly the pulmonary hypertension and Eisenmenger syndrome and ASDs. Let's circle to kind of the big question that everyone will wonder about is whether it should be closed or not. Let's say she does have a flow greater than 1.5. How do we close it? Sorry, let me rephrase this. There's an indication for closure for her. Let's rephrase. Let's talk about the methods in which closure can be done. There's percutaneous options and then there's surgical options. Which one would be preferred for her, a young, 45-year-old woman?
Khanna: If I told you that you could have a procedure where you're in the hospital, you come in for the cath lab. You're in the hospital overnight. You go home the next day and you're back to work in a few days. Or we can do a procedure where we saw open your sternum and stop your heart and sew a hole closed. You're in the hospital for a week and you're out of work for 6 weeks. What do you prefer? That question is easy. People prefer the percutaneous, so we recommend percutaneous options if possible. That is our go-to that we should do a percutaneous if we can do a percutaneous. The question really is who can have this easier recovery kind of procedure, because most of us in congenital heart disease really feel the long-term effects of both of them are very effective. There's equipoise between them. It's not like if you have it surgically closed it'll really be closed and it's better. There's really no long-term benefit to either option.
Perry: I was going to ask that question about the durability, so they're the same.
Khanna: They are the same. It's really about short-term and the recovery period that's different. Who can have it percutaneously closed? First is what we already talked about. You can't have other problems with your heart that need to be fixed. If you have anomalous pulmonary veins or if you have a mitral valve that's moderately leaking or more, or if you have some degree of aortic stenosis and we really should do something about the aortic valve, if you have something else wrong with your heart, then we should really just do surgery and fix whatever is there that needs to be fixed.
First of all, you have to have only a secundum ASD. Why secundum? Only secundum because we need rims to anchor a percutaneous device to. Percutaneous devices are like two plates or two Frisbees that are anchored in between the septum and they hold position there, and the device is released and it stays in the heart forever. These two plates have to hold on to something. There needs to be a rim of tissue around almost the entire hole for the plates to hold on to so that they don't become dislodged after it's been released. You need to measure the rims. Some people do a TEE, which probably gives us the best measurement of the rims. Some people will look on the MRI and see if the rims look good enough on the MRI and then do a TEE when they're doing the procedure just to confirm. If there's any doubt, you end up having to do a TEE to actually measure these rims going around it. But other types of ASDs, they don't have rims adequately for us to anchor a device. If it's a primum ASD, it's a sinus venosus ASD, those are all surgically repaired.
Perry: Because those two ASDs you mentioned, the primum ASDs and then the sinus venosus ASD, these are off to basically, you can think about off to the sides of the septum where there's not really a lot of extra septal tissue around it, unlike the secundum ASDs that are kind of, one way to think about it is they're in the middle sort of of the septal tissue, so there's usually places for these disks to latch on to and clamp on.
Khanna: Yes, exactly. You need to have suitable anatomy for a percutaneous closure.
Perry: It becomes maybe more of a technical issue of whether you can do the percutaneous option rather than indications for durability of options. It becomes a technical consideration at this point.
Khanna: Yes, some secundum ASDs are so large that, even though they're a secundum ASD, there's not adequate rims. There's not enough tissue surrounding the hole. It almost becomes like a common atria, that there's just one massive hole in the middle.
Perry: Now one question we skipped over, I forgot, is for this patient or for all patients with ASDs, how likely is it that they have a genetic cause causing their ASD? Frequently, we think of patients with congenital heart disease, maybe not frequently, but sometimes these conditions are associated with genetic mutations. Should we be concerned about that for someone with an ASD?
Khanna: The vast majority of ASDs do not have a genetic component. I would start asking questions if there was a family history. If they say, "Oh yeah, my mom had that and my sister had that." There are some autosomal dominant forms of ASDs. There are a lot of genetic conditions or syndromes that have pretty significant physiologic findings, that when we see the syndrome, we look for congenital heart disease. It's a little bit of a backwards question. But if you have an obvious genetic syndrome, we oftentimes are looking for the congenital heart disease. But when we find a secundum ASD, we don't really look for it. ASDs are on the spectrum of canal-type defects that used to be called endocardial cushion defects. A true endocardial cushion defect is an ASD and a VSD right in the middle of the heart. That is strongly associated with Down syndrome. Primum ASDs alone, without the ventricular septal defect portion of it are not necessarily associated with Down syndrome. There are a lot of neurotypical, genetically-normal people with primum ASDs. I'm always looking for genetic syndromes or things that I think may be a red flag for it, but an ASD alone would not be a red flag for it.
Perry: Got it. Interesting. Now, let's flip the conversation. We talked about different options for closure, surgical versus percutaneous. What if we don't need to close her ASD? Let's say the Qp/Qs flow ratio is less than 1.5 and let's say her right ventricle actually wasn't dilated. Maybe her right atrium is just a little dilated. What sort of follow-up would be indicated for her?
Khanna: I think it depends. If the right atrium is a little bit dilated and her Qp/Qs is 1.4, I would follow her again in a year to make sure things aren't rapidly changing, and then I'd always follow probably every 2 or 3 years to make sure things are looking okay. If it's really a tiny hole, we're talking 2 or 3 millimeters and everything looks absolutely perfectly fine, you could say come back if you have problems. I'm pretty bad about doing that. I almost tell everybody to come back, but it would be a 5-year kind of thing. Let's just take a peek at this again in 5 years and see what it looks like.
Perry: Now let's say we release her into the wild and say, "Come back in 1 or 2 years," sort of thing. Does she need to take antibiotic prophylaxis for any dental work?
Khanna: No. ASD alone is not an indication for antibiotic prophylaxis. If she were to develop Eisenmenger syndrome and was cyanosed, you could consider it based on the cyanotic congenital heart disease. If she gets percutaneously closed and now has foreign material in her heart, she should be on antibiotic prophylaxis for 6 months after the procedure is done. Not daily for 6 months, but prior to dental work, if she were to have dental work in the 6 months after her...
Perry: After her closure.
Khanna: Yes. I had one patient who nearly fit this picture. She was a bit younger and she basically said, "No, I feel fine. I don't want it closed." That's a bit of a different situation where I said, "I think you should have your ASD closed," and she said, "No, thank you." We followed her every year with echocardiograms. We did exercise tests and we watched her a lot more carefully, because she actually did have indications for closure. I think I followed her for 3 or 4 years and her ASD was too large for percutaneous closure, so she underwent surgical closure just 3 or 4 months ago and is doing really well.
Perry: Now, wrapping up, I think most of my questions about ASDs for this case. But I also know sometimes it gets confusing when we're talking about PFOs, patent foramen ovales, and then ASDs. Could you just explain fundamentally what are the differences between these two defects?
Khanna: That's a great question. A PFO is a flap in the atrium where if the pressure is right, it opens up. If the pressure between the left atrium and the right atrium changes, it closes again. 100% of people have a PFO on the day that they're born. PFOs are necessary for intrauterine fetal circulation. 80% of the time that tissue seals shut, closes and seals shut tight. 20% of the time it doesn't. 20% of the population is walking around with a patent foramen ovale, meaning if the pressure change is such, the flap will open up and allow some blood to cross between the chambers. It is not generally thought to be ever enough blood to cause chamber enlargement of either the left side or the right-sided chambers. It is definitely not something that we close because it's there. We would be doing these device closures in 20% of the population if that was the case.
Most people believe that PFOs are associated with stroke, particularly stroke in young people without any other good reason to have a stroke. In select populations, very select populations, we will close a PFO to prevent a recurrent stroke. We are working on how to find the patients that actually will benefit from this being done. I don't think we've totally refined those guidelines yet.
Perry: Sure, yes. I know there's been a lot of research and there's arguments on both sides of the case, on both sides of the fence right now regarding PFO closures.
Khanna: Right. My biggest recommendation is if you have somebody who has a stroke and they have a PFO, send them to a multidisciplinary PFO stroke clinic. Have them be seen by a cardiologist that closes PFOs and a neurologist that's familiar with the data and the research regarding PFOs and embolic strokes. Good PFO clinics, those two physicians will sit side-by-side and see patients together. If it were a family member, that would be my recommendation is go to the experts.
Perry: Cool, I didn't know those existed. Nice. I think that wraps it up. Should we move on to our second case?
Khanna: Yeah, so one last piece. Somebody has severe pulmonary hypertension. Whether they have an ASD and an Eisenmenger syndrome or they have primary PH and a decent-sized ASD, we don't close the hole. If there's a hole and the Qp/Qs is sort of in that one range, close it. The patients struggle. Oftentimes, once you develop severe pulmonary hypertension, that hole acts like a pop-off valve for the right ventricle. It allows the right ventricle and a smaller amount of blood flow so it doesn't have to deal with the full circulation and allows some blood to cross over to the LV so that even though not enough blood is coming through the lungs, it's getting adequate preload from the PFO.
Those patients will do very poorly if you suddenly close their PFO. The right heart fails because it now has to deal with the total circulation of the body and cardiac output drops because there's no blood actually making it to the left ventricle. There are some studies and some clinical experiences wherein patients with primary PH we create holes in the heart, so a small ASD to try to offload the right ventricle and get enough blood flow to the left ventricle. It's not that we don't think it will help. It will actually harm the patient, so we don't do it.
Perry: Maybe another way of saying that was that there's a point in which the right ventricle can be so strained and so overwhelmed. That's what this severe pulmonary hypertension would be like and this is what Eisenmenger syndrome looks like. We've gone too far to think about closure and that's really keeping the right ventricle happy.
Khanna: Yes. Absolutely.
Perry: Our second case is a 30-year-old man. He comes to an internist to establish care. He hasn't seen a physician in many years, like since he was a child like probably most 30-year-old men in our country. He was told he had a hole in his heart and his wife told him he had to come into the doctor to make sure it was okay. When you examine him, there's a loud, harsh holosystolic murmur at the lower left sternal border. You order an echocardiogram and it demonstrates a VSD in the membranous portion near the tricuspid valve, tricuspid leaf. Same first question for him. What additional diagnostics should be performed to evaluate his VSD?
Khanna: Again, a very common situation. This happens all the time. I see patients just like this in my clinic regularly. It is always the wife that tells them that they should go get it checked out. [LAUGHTER] That is exactly what happens. I am very reassured by how loud his murmur is. All holes make a lot of noise. The fact this is still a very loud murmur implies it is still a very small hole and is probably not causing problems. Most VSDs that can and should be closed have it done in childhood. People don't miss VSDs in babies. They make a ton of noise. Parents come in and say, "Why is the chest vibrating with every heartbeat?" VSDs are picked up in childhood in developed countries with adequate access to medical care. They're picked up in kids. They're diagnosed and they're treated if they need to be treated. If the VSD is small, oftentimes they won't be closed, because it's making a lot of noise but it's not that hemodynamically significant. If it's making a lot of noise in a kid and it's a good-sized hole, then they'll close it when they're a kid. By the time you reach adulthood, it's rare. It's not an absolute, but it's rare to find a VSD that should be closed based on its size. Usually we can... go ahead.
Perry: To explore that concept of the small hole being loud, this is because there's a large pressure difference between the left ventricle and the right ventricle, and so we have a high velocity across this area creating turbulent flow and that's what you're hearing when you're auscultating.
Khanna: Yeah, it's like the end of a garden hose. As you start to put your thumb over the end of it, the velocity of the water gets faster and faster, gets louder and louder until you finally seal it off.
Perry: Perfect.
Khanna: Usually with patients like this, I can get a transthoracic echo, see that the left ventricle, left atrium are normal size, measure a high velocity flow across the VSD, look at the valve function, make sure the tricuspid valve is still working fine, that it hasn't been damaged at all. Look at the aortic valve, make sure the aortic leaflets haven't been sucked into the jet of the VSD, and follow based on that. We can get reassuring enough information from an echocardiogram that we don't necessarily have to do more testing. If we're on the fence, if the left atrium looks a little bit big, if the hole just looks a little bigger than I was expecting, then we can do a cardiac MRI again and get more information about the size of the ventricles and the Qp/Qs.
Perry: You say usually they're picked up as children. Then the ones that need to be treated, is it possible that there's a child who then has a VSD, but then it has expanded throughout their life because our hearts are growing from some size from a child. Does that hole also possibly enlarge when this person is maturing?
Khanna: It usually doesn't. Usually, if anything, gets a little bit smaller as the muscle grows more and sort of fills in. If there's a muscular component to it at all, the muscle will fill in that, so it would be uncommon for the shunt to get larger as patients get older.
Perry: What are the types of patients who present to you with VSDs who need closure, since you're saying most of these patients should have been picked or most of them probably would have been picked up as an infant?
Khanna: They don't need to be closed usually because of the size of the VSD or because of the size of the shunt. The ones that need to be closed are closed for another reason. The other reasons are progressive valve dysfunction. If the tricuspid valve or the aortic valve is starting to get damaged, it's better to go in, close the VSD, and save the valve than to wait for the valve to be destroyed and have to do a valve replacement. I would rather operate to close a hole than to replace a valve because of long-term prognosis. If you see the valves are starting to get damaged, there's something called a double-chambered right ventricle, which is uncommon, but it can happen and it's one of the reasons that we do need to follow these VSD patients. If that jet of flow from the left ventricle to the right ventricle hits the wall of the right ventricle, you can start to get muscular hypertrophy at that site. The muscular hypertrophy from the jet of flow can actually cause RV outflow obstruction, and then it starts to behave a little bit like HOCM (hypertrophic obstructive cardiomyopathy) on the left side, but it's on the right side.
Perry: Interesting.
Khanna: The double chambers are on one side of the obstruction and the other side of the obstruction within the right ventricle, you can get significant enough flow across there that you have symptoms and the right ventricle won't tolerate that forever. You watch to see how fast that flow is crossing within the obstruction within the right ventricle, and if it gets high enough, then you go and you do surgery. You close the VSD and often have to do some muscular resection within the right ventricle.
Perry: Like a myectomy.
Khanna: A myectomy, exactly.
Perry: Interesting.
Khanna: The final indication for VSD closure is endocarditis. There's tissue around the VSD. If that ever gets infected, we recommend closing the VSD to prevent recurrent episodes of endocarditis.
Perry: Any types of endocarditis, say IV drug user, right-sided tricuspid valve endocarditis? Does their VSD need to be closed?
Khanna: Probably. Definitely if you're in there anyway. If they are getting a tricuspid valve replacement, you should close a VSD. Honestly, if anybody were having another heart surgery and they had a VSD, we would probably recommend that they try to close it. VSDs are really easy to see on echocardiograms when the heart is full of blood and there's this big, bright, jet of flow going across. In the operating room, they're actually much more difficult to find. Now there's no blood in the heart. The ventricles are very trabeculated, so you have all of these little crevices, and it can be difficult to find the one crevice that crosses over into the other ventricle. Surgeons do the best they can, but there are some patients that had a VSD closed and they still have a small residual VSD. Actually, it's fairly common just given how it's hard to get 100% closure of a VSD.
Perry: Are there any percutaneous options for closure in VSDs?
Khanna: I don't believe there are any FDA-approved options. They do some in Europe. No, we do muscular VSDs, but those are more often done in kids. Most adults don't have muscular VSDs anymore. They've either closed or they've had them closed. Postinfarct VSDs, we close those. But this patient has a perimembranous or a membranous VSD. We don't have perimembranous or membranous VSD closure devices in America. The studies where they've done them have been associated with a high risk of heart block because the conductive tissue goes right next to where the VSD is. Now, we talk to a patient and we can say, "We can do surgery. It's 6 weeks recovery, but your conduction system will work. Or we can do a percutaneous and you will be dependent on a pacemaker the rest of your life." All of a sudden, that surgery doesn't sound like such a terrible option anymore.
Perry: With ASDs, you had mentioned there can be a point with severe enough pulmonary hypertension you don't want to close them. Can the same situation occur with VSDs?
Khanna: Yes. For a big VSD, it probably happens by about 2 years of age. If it's a big VSD, most of them will develop permanent pulmonary hypertension as a mechanism of protecting the lungs because otherwise you're overcirculating with a high velocity flow, but it has to clamp down and it has to clamp down so well that you develop pulmonary hypertension where the vascular remodeling happens. Usually, too, it's actually probably by about 1 in patients with Down syndrome. If they don't have Down syndrome, you have a little bit more time to fix a big VSD.
Perry: Now if our patient does not need closure, what should his follow up look like?
Khanna: Honestly, we should probably look every 5 years. I tell patients 2 to 3 [LAUGHTER] because they'll come back in 5. [LAUGHTER] We should periodically look. We should look at the valves and make sure that the valves aren't starting to deteriorate, make sure that there isn't hypertrophy of the right ventricle wall. We should look because we can catch things in which there's an intervention that is better than if we didn't catch it.
Perry: Other thoughts about VSDs?
Khanna: There's always a question: it's just a simple VSD, a general cardiologist can take care of this. I think if a general cardiologist is familiar with VSDs, is familiar with these long-term complications, then yes, that's fine. What makes me uncomfortable is when a general cardiologist says, "It's just a small VSD. Goodbye. You'll do fine. Call me if you have any problems." As long as the general cardiologists are following the guidelines and know what to look out for, then I think it's fine. Otherwise, most of my colleagues, adult congenital cardiologists, we are more than happy to see these patients, provide guidelines, recommend long-term follow-up options, and see these patients. Because of that, I think that all patients with a VSD should see an adult congenital cardiologist at least once to make sure there's nothing missed and to get a long-term follow-up plan.
Perry: As kind of a wrap up, do you have any resources for further learning or understanding that you might be able to recommend?
Khanna: In 2018, the for the management of adults with congenital heart disease. It really goes through each lesion and tells you what follow up should be, how we're going to classify patients, what testing is indicated, what to do in the unrepaired patient, what to do in the repaired patient, very systematically goes through everything. If you're taking care of these patients, it's a great resource for knowing what appropriate care really is. For patients, the , is a very good resource as well. I send my patients to the website. They have conferences. It's a great patient resource for meeting other people that have similar problems to them and, especially around the time of surgery, talking to other people who have been through heart surgery, what it's like, what kind of complications they can have. It's just a really good resource for patients.
Perry: That's the ACHA.
Khanna: Yes.
Perry: Thank you so much for visiting with me and letting me chat with you. I learned a lot and I think other people will as well.
Khanna: Absolutely. Thank you for having me. I really enjoyed it.
Perry: To summarize a few of the main points, in patients with an ASD, a cardiac MRI is a useful test because it can better define the anatomy of the ASD and additionally can look for other conditions that may coexist such as anomalous pulmonary veins. The closure for ASDs should be considered if the patient is symptomatic from them and when the Qp/Qs is greater than 1.5. In other words, when the flow through the pulmonary system is 50% greater than that through the systemic system. For patients with a VSD, small VSDs can just be followed and monitored clinically for long periods of time. If they've had endocarditis, the VSD should probably be closed. In both sets of patients with ASDs or VSDs, patients with severe pulmonary hypertension or Eisenmenger syndrome with right-to-left shunts, these defects probably should not be closed as they are a type of a pop-off valve for the pressures and the heart could fail with closure of those valves. I hope you enjoyed the episode and we'll see you next time.
, is a cardiology fellow at the University of Washington Medical Center in Seattle.