Dr. Sarah Gubara (Host): This is Transformational Pediatrics with Children's Mercy, Kansas City. I'm Dr. Sarah Gubara. And today, we are discussing STEMI with Dr. Lindsay Malloy-Walton, Associate Division Director for the Heart Center and Medical Director for Inpatient Cardiology; Laura Martis, Pediatric Electrophysiology Nurse Practitioner; and Dr. Jennifer Flint, Pediatric Cardiac Intensivist and the Medical Director for Pediatric Critical Care Transport. Welcome in, everyone. We're so excited to talk to you about this new innovation.

Laura Martis: Thanks for having us.

Dr. Lindsey Malloy-Walton: Thank you for having us.

Dr. Jennifer Flint: Yes. Thank you, Dr. Gubara.

Host: Of course. So, let's set the background. What makes STEMI in pediatric patients unique compared to adults?

Laura Martis: Well, it is unique because pediatric STEMI is a completely different disease than adult STEMI. The reason for that is the underlying mechanism is just very different than with adult STEMI, and it can make the diagnosis really challenging. So, adult STEMI, as we know, it's almost always caused by plaque rupture, and then acute coronary thrombosis. But in children, that mechanism is pretty much non-existent.

We recently did a study that covered the last 10 years of our facility as well as an adult facility in our city. And we screened almost a thousand patients that presented with symptoms of myocardial infarction. But really, only 13 pediatric patients truly met the MI criteria, and none of them had the classic plaque rupture type 1 STEMI.

What we know is that pediatric STEMI, instead of being the typical type 1 STEMI, it's usually tied to structural issues like congenital heart disease, coronary anomalies that may be related to congenital heart disease or other coronary abnormalities that may be present, like the ones that we see after Kawasaki disease. Patients with MI or signs of MI, like chest pain and ST-segment elevation may actually not have anything ischemic but may have something like pericarditis, myocarditis, or even drug intoxication.

Host: Wow, a thousand patients. What are some of the underlying conditions and how does this rarity create diagnostic challenges?

Laura Martis: Yeah. So, the rarity of it and the fact that a lot of the patients that are under 18 that truly are meeting criteria for MI, those patients just often have a different cardiac physiology, meaning they may have congenital heart disease or undiagnosed coronary anomalies like an ALCAPA or other coronary anomalies. So, just because the physiology of it is so different than what we see in adults, it can make the diagnosis really challenging.

Host: Thank you for sharing that. So, when children and adolescents present with suspected STEMI, what symptoms or atypical signs should clinicians look for?

Laura Martis: I think the biggest thing to recognize is that the signs of MI in children aren't always the typical signs that we associate with STEMI, especially in adults. So, chest pain in adults is really concerning, because it can be a sign of MI. But only about three-fourths of the patients that we saw in our study came in with chest pain.

We also saw patients present with syncope or shortness of breath or nausea that was associated with the pediatric patients having a true MI. But it was interesting that cardiac arrest was really the first presenting symptom in patients that we saw with congenital coronary anomalies that were undiagnosed.

Host: So, how should diagnostics like ECGs, biomarkers, and imaging be interpreted differently in this population?

Laura Martis: Every patient in our cohort had ST-segment abnormalities on their EKG, but these patterns really weren't reliable indicators of coronary occlusion. So, we saw pretty much all types of ST-segment elevations, including lateral, inferior, interseptal, as well as diffused. And in some kids, these changes were really just due to pericarditis and not ischemia at all. It's also important to know that repolarization patterns vary with age and are different in the pediatric population. So while the EKG can point you towards ischemia, it really shouldn't be the only deciding factor in pediatrics.

It was also interesting that troponins were elevated in every patient that we had in this cohort. But really, that doesn't equal MI because kids can have an elevated troponin with things like myocarditis, arrhythmias, after resuscitation, trauma, sepsis, all of those things. It can tell you that there's myocardial injury, but they're not necessarily having a STEMI.

So really, it's important in the pediatric population to think about advanced imaging like a cardiac MRI or a CT, because this may identify previously unknown congenital heart disease.

Host: Thank you. Now, your study reviewed over 10 years of data. What prompted you to investigate suspected pediatric STEMI? And what surprised you the most about these cases?

Dr. Lindsey Malloy-Walton: So as in many cases, there was a problem that we identified. We started to see at our institution, although rare, an increase in poor outcomes with patients that we sent for a pediatric STEMI evaluation to our adult collaborating facility. When we reviewed the literature, there was limited published data available.

So, recognizing that pediatric patients are not just small adults, we began to question our diagnostic approach and pathway for these patients at our institution. We found that, over 10 years of data, less than 2% of patients or 13 total with billing codes relating to a myocardial infarction met the widely used adult criteria of ST-segment changes and elevated cardiac biomarkers.

What surprised us the most was that most patients presenting with a STEMI concern had congenital heart disease with some patients being underdiagnosed at the time of the initial presentation.

Host: Now, given the high rate of congenital heart disease, including undiagnosed cases, what does your research reveal about early recognition, risk stratification, and common diagnostic overcalls, especially ECGs?

Dr. Lindsey Malloy-Walton: Yeah. So for pediatric patients presenting with a STEMI concern, a high suspicion for congenital heart disease is absolutely essential. ECGs are a helpful tool for demonstrating a STEMI in adults — that we know. In pediatrics, ECG findings can be really difficult as the cardiac structure changes with age, and more common non-ischemic conditions may present with similar ST-segment changes. Thorough non-invasive diagnostic evaluation with advanced imaging is really key to ensuring that these patients are managed effectively.

I would also point out that conducting a cardiac catheterization in a pediatric hospital may help address the unique complexities associated with pediatric myocardial infarction, really ensuring that congenital anomalies are adequately considered, and appropriate interventions are carried out in a timely manner at a facility with congenital heart disease expertise.

Host: So, most catheterizations at the adult facility resulted in no interventions. What does this tell you about applying adult STEMI algorithms to pediatric patients?

Dr. Jennifer Flint: So, this is really interesting. And as an internal medicine and pediatrics-boarded physician, I think initially our desire was to get these patients to an adult facility for coronary catheterization, assuming that they were having a similar adult-type STEMI. But, as our other guest, Dr. Malloy-Walton and Laura Martis described, these patients are presenting with things like congenital heart disease and other coronary anomalies that don't amend themselves well to adult algorithms.

It tells us really the etiology of chest pain and EKG changes in children and adolescents is very different. And pediatric patients need pediatric-specific algorithms that are really geared towards evaluating congenital heart disease. And we discovered that it should be formed by providers that are really familiar with diagnosing and managing congenital heart disease, especially at an institution such as a pediatric facility, where there's resources available to care for those pediatric patients.

Host: Thank you for sharing that. And so, as you're modifying adult STEMI algorithms for pediatric patients, what recommendations do you have for how these pathways should be adapted? I know you touched on it a little, but we'd love to hear more.

Dr. Jennifer Flint: I think we just have to be really thoughtful about the underlying etiology. Based on our study, we know that plaque rupture and the need for percutaneous intervention with a stent placement or balloon angiopathy is not what any of our pediatric patients needed. And so, really, the pathways need to be adapted to plan for that. We don't need to be rushing our pediatric patients to an adult cath lab, similar to how we do it for adults. We need to be thinking differently.

Host: How did your collaboration with an Adult Level I Heart Attack Center influence your team's management decisions?

Dr. Jennifer Flint: So, this was really great to have a really well-established relationship with our Adult Level I heart attack center. Because we had started out with processes that involved taking our pediatric patients to the cath lab, just like an adult. But after our study, we all learned that that was probably not the best approach. And so, we have worked really closely with our collaborating facilities, both on data collection in the study, and then also amending our protocols and processes to have our pediatric patients brought directly to the pediatric facility with appropriate evaluation.

Host: Tell me more about some of these protocol changes. What did your institution change as a result of the study?

Dr. Jennifer Flint: So, as we mentioned before, none of our pediatric patients who went to the adult facilities required any sort of coronary intervention in the cath lab. And we unfortunately had a couple of patients in our study who had cardiac arrest and unfortunate outcomes at those adult facilities.

So, we worked with our adult partners. And we have decided to divert all ambulances and transported patients directly to our pediatric facility, where we have an emergent cardiology consultation and an echocardiogram followed by CT or angiography of the coronaries here at the pediatric facility, depending on the clinical situation.

And then, our adult colleagues continue to remain available for additional consultation. So if we have a pediatric patient, especially an older adolescent with some EKG findings that are concerning and maybe they need to be transferred to the adult facility, we still have that established relationship and we can easily facilitate that transfer if needed.

Host: Wonderful. What are some of the key takeaways for clinicians managing high-risk pediatric patients, particularly those with structural coronary anomalies?

Laura Martis: One of the biggest takeaways is that, if a pediatric patient comes in and they have signs of a STEMI and ST-segment changes, really the chances of them needing an emergent percutaneous intervention in a cardiac cath lab, that's really low. And we didn't see any of that over 10 years. But what these patients need is pediatric cardiology involvement. So, I think, a key takeaway is that they just need more imaging. And they need to be evaluated for congenital heart disease, because we did have a few patients in this cohort that did have undiagnosed coronary anomalies that didn't need to go to the cath lab at all, but actually ended up needing surgery.

Dr. Lindsey Malloy-Walton: I think my biggest takeaway is we do it best, right? I think STEMI is often thought of as an adult disease process and more common in the adult world. And I think that's very true when compared to the pediatric world. But when we really think about our pediatric patients, where they're really served best is evaluation in a pediatric center with resources available to really rule out congenital heart disease.

Dr. Jennifer Flint: One of the things I took away from this study was really an awareness and getting out education to our first responders and our adult ER colleagues, because they are used to diagnosing these adult STEMIs in the field and activating their adult processes, and really getting out the awareness and education that children are different and they should be evaluated as soon as possible at a pediatric facility that's capable of evaluating children for especially coronary anomalies and congenital heart disease is important.

Host: You're right. That's so important. And I'm going to extend this final question out to all three of you. So pie in the sky, what future research or multicenter efforts do you all think are most needed?

Laura Martis: So, even though we were able to screen a lot of patients over several years, this study was still pretty small in the grand scheme of things. So, I think that pediatric hospitals all over the country should really look at their data and see how many pediatric type 1 STEMIs they had. That way, we can all come together and maybe create some standardized guidelines because there really just aren't any out there.

Dr. Jennifer Flint: Yeah. Laura, I'm with you. I would love it if we could have multi-institutional data inputted from all of the large pediatric cardiac centers to evaluate STEMI in children. Because I agree, this study was so small, it's really hard to draw conclusions at a big level. But if we had more data and we had a better idea of pediatric STEMI across the nation, we could definitely help come up with standardized processes.

Dr. Lindsey Malloy-Walton: I absolutely agree. A standardized guideline to really ensure that we have consistent and effective management of these patients in a multi-center means would be the best. Although it's really challenging because this patient population is so small. I do think it is essential, and it can be life-threatening. And I think it's essential that we continue to try to standardize this process over time.

Dr. Sarah Gubara (Host): Thank you all for educating us on pediatric STEMI and your incredible work in this research. It has been wonderful to learn and really gets us thinking about what our pediatric patients need the most. Lots of thanks to Dr. Lindsay Malloy-Walton, Laura Martis, and Dr. Jennifer Flynn. Thank you all for being here today.

Laura Martis: Thanks for having us.

Dr. Jennifer Flint: Thank you.

Dr. Lindsey Malloy-Walton: Thank you.

Dr. Sarah Gubara (Host): Of course. this has been Transformational Pediatrics with Children's Mercy, Kansas City. To refer your patient or for more information, please visit childrensmercy.org to get connected with one of our providers. Please remember to subscribe, rate, and review this podcast and all other Children's Mercy podcasts.