Coronary Artery Anomalies Program

Evaluation and Testing

ECG

There has been an increase in the number of children and adolescents diagnosed with AAOCA after routine physical exams prior to sports participation due to the presence of a heart murmur or an abnormal electrocardiogram (ECG). One of the first tests your child will have is an ECG. This tells your medical team about the patient’s electrical activity of the heart. The ECG is done at nearly every cardiology visit.

Echocardiogram

Typically, an echocardiogram is performed when there is an initial concern for a cardiac condition and the diagnosis of AAOCA is suspected.  The echocardiogram is an ultrasound of your child’s heart. Your child may have already had an echocardiogram, and subsequently referred to the CAAP for concerns of anomalous coronary artery. The echocardiogram is usually done during the first visit. If your child has a surgical intervention, then the test will be repeated after surgery as well. If your child undergoes surgery, the echo will also be repeated after surgery prior to leaving the hospital.

CTA

Clinicians typically use computerized tomographic angiography (CTA) to image the heart and coronary arteries, the preferred method at Texas Children’s, given its precision of details given, but other institutions may choose to use cardiac magnetic resonance imaging (CMRI).

The CTA is a quick scan of your child’s chest to look at the heart and coronary artery anatomy in more detail and can identify AAOCA. The CTA usually does not require sedation, but may be necessary in rare cases. The scan is usually completed in 5-10 minutes. The CTA shows your medical team detailed images of the coronary arteries. 

The image to the right is a clip of a CTA that shows an AAOLCA. The coronary artery is much lighter than the heart muscle. As you can see, the left coronary artery is located close the right coronary artery and is narrowed.

Intravenous (IV) catheter: An IV is a tiny straw that is used to give the body medicine. Your child will need an IV for contrast medication. Your child might feel a pinch or a poke as it goes in the vein, however, we have ways to manage any pain associated with this procedure.

Begin talking to your child about the CTA experience 2-4 days prior to the appointment. Be honest and use simple terms like: “we are going to the hospital to take pictures of your body”. It may be helpful to watch a video about the procedure at the following website: https://www.texaschildrens.org/departments/radiology

Exercise Stress Test 

The evaluation process at our CAAP includes functional assessment of the heart muscle during exercise to study adequacy of blood supply to the cardiac muscle (at rest as well as during induced stress). The exercise stress test is done with the patient running on the treadmill with the ECG and face mask applied. The test informs your clinician about any abnormal waveforms or beats or abnormal oxygen consumption that would be concerning for ischemia. Typically your cardiology provider will inform you of the test results during clinic. 

Treadmill

How to prepare: Wear comfortable clothes to exercise in (shorts, sweatpants, t-shirt, athletic shoes). Bring a bottle of water.

What to expect during the treadmill exercise stress test: We attempt to exercise the patient to a maximal effort >85% of maximum heart rate.

• Treadmill stages start off very slow and progresses every 3 minutes to provide more incline and speed in order to increase the heart rate of the patient.
• There is no set amount of time that the patient has to be on the treadmill, however we do need the patient’s full cooperation and a maximal effort.
• Reasons for test to be stopped 
  • Once the patient can no longer exercise at the current stage (speed and incline), test is stopped for the patient to recover.
  • Patient is having symptoms such as (chest pain, dizziness, or shortness of breath).
  • Staff determines it is no longer safe to continue.

Stationary Bike

Depending on the patient’s diagnosis, and/or physical ability, stationary bike may be an alternative to the treadmill. Just as in the treadmill test, we will attempt to exercise the patient to a maximal effort >85% of maximum heart rate.

How to prepare: Wear comfortable clothes to exercise in (shorts, sweatpants, t-shirt, athletic shoes). Bring a bottle of water.

What to expect during the stationary bike exercise stress test

• Test begins with no resistance on bike, and progresses every minute to provide more resistance to increase the heart rate of the patient. 
• Exercise should be expected to last on average 8-12 minutes. 
• Reasons for test to be stopped:
  • Once patient can no longer pedal, test is stopped for the patient to recover.
  • Patient is having symptoms such as (chest pain, dizziness, shortness of breath).
  • Staff determines it is no longer safe to continue.

MVO2

• This will be ordered by your cardiology provider and performed during the exercise stress test.
• It is a metabolic test to measure oxygen and carbon dioxide levels during exercise.
• The patient wears a mask, during exercise on treadmill or stationary bike, to collect data points.

Complete test (MVO2 with pre & post PFTs)

• In addition to MVO2 with the treadmill or stationary bike, this test also measures Pulmonary Function Testing (lung function) before and after the test. This is also known as “PFT” or “spirometry” testing. 
• This test is helpful to determine any cardiopulmonary abnormalities with relation to exercise.
• Staff will coach the patient on how to perform PFT correctly (just prior to this portion of the test).
• The patient will use a mouthpiece to blow as hard as they can for 6 seconds, with one breath. The breaths are done 3 times before exercise and 3 times after exercise.

Cardiac stress MRI (sCMR)

The sCMR uses medications to stimulate responses in the heart that occur during exercise. The sCMR looks for low blood flow or no blood flow to any part of the heart muscle. Medication is given during the sCMR to help the heart beat faster, to mimic exercise.   

What is CMR?  The CMR uses a big magnet to take pictures of the heart, looking at the heart muscle with great precision. The CMR does not use radiation and has few known side effects.

What is stress CMR (sCMR)? A sCMR includes medication given during the scan to mimic the body’s response to exercise. This is helpful to identify any ischemic areas (low or no blood flow) in the heart muscle during stress and comparing it during the rest state.

What to expect during a sCMR:

The patient will be positioned on the MRI table. Once positioned, the table will move inside the scanner’s tunnel. The scanner is open on both ends; it may feel close, but it will not touch them. The scanner makes loud noises while it is taking the pictures. It may sound like a shoe in the dryer or a loud beeping noise. The patient will be given earplugs and headphones to reduce machine noise, but still allows our staff to communicate with them during the exam.

It is essential for the patient to lie still inside the scanner for the duration of the exam. This scan can take anywhere from 60 to 90 minutes. Any movement can make the picture blurry and limit important information about the blood flow to the myocardium. The majority of our exams will allow the patient to rest and watch a movie through special glasses/goggles or listen to music during the scan.

Contrast medication is given during this exam. Contrast is a special medicine that helps certain body parts highlight or show up better on the scan.

There will be a short period of time, of approximately 5-10 minutes, in which your child may feel his/her heart beating faster, similar to heart beating faster while running. This is expected as the clinician gives your child medication (through an IV) to slowly increase the heart rate, as the radiology technician takes pictures of your child’s heart beating faster. We will let your child know when this will occur. Our team is readily available to answer any question your child may have during the test. Your child will have a button to push to call the clinician as needed.

One adult or legal guardian is allowed to stay in the room during the scan if your child is not receiving sedation.

Intravenous (IV) catheter: An IV is a tiny straw that is used to give the body medicine. Your child will need two IVs – one for contrast medication and other for medicine to speed up the heart. Your child might feel a pinch or a poke as it goes in the vein, however, we have ways to manage any pain associated with this procedure.

Before the sCMR

• Begin talking to your child about this experience 2-4 days prior to the appointment. Be honest and use simple terms like: “we are going to the hospital to take pictures of your body. 
• It may be helpful to watch this video about the procedure at the following website: https://www.texaschildrens.org/departments/radiology
• Have your child lie on his or her back and practice holding still while watching TV for 20 minutes.
• Attire: Your child will be given a hospital gown to wear.
• Bring a comfort item like a blanket or stuffed animal.
• Arrive on time. We ask that you arrive 120 minutes early to prepare for an appointment with sedation/anesthesia and 60 minutes early for an appointment not requiring sedation/anesthesia.
• We recommend not eating any solid foods within 2 hours of start of the scan. However, in the case of scan without sedation your child is able to drink clear liquids until the time of the scan.
• Review this information with your child and confirm his or her understanding of the procedure. Assess your child’s anxiety level and ability to hold still

Coordinating the sCMR 

Some children as young as six years old may be able to hold still with the proper preparation. Our anesthesia policy states girls six years and above and males eight years and above, who are developmentally appropriate, will not be scheduled with sedation.

If your child is scheduled for sedation/anesthesia, there are guidelines you must follow in order to prevent your child from experiencing side effects such as vomiting, among others. If you do not follow these guidelines, for the safety of your child, the sCMR appointment may need to be rescheduled.

Please ensure the patient does not eat or drink:

• Caffeine or chocolate products day prior and the day of the MRI.
• Clear liquids (water, Gatorade, apple juice) within two hours of the MRI.
• Breastmilk within four hours of the MRI.
• Non-human milk or a light meal within six hours of the MRI.
• A heavy or fatty meal (fried foods, meats and cheeses) within eight hours of the MRI.
• The nurse coordinator will ask you about what medications the patient is currently taking. In some cases, medications may be stopped for the test, and then restarted after the test. The nurse coordinator will give you instruction regarding medications.

Your sCMR coordinator will go over all the details with you a few days prior to the test.

Patient Safety

Our MRI team is dedicated to the safety of our patient and family members. You will be required to fill out an MRI Safety Screening Form for your child and for yourself prior to entering the MRI area. If you have any questions or need help with MRI Safety Screening Form, please ask for assistance. The nurse and technologist will go over this form with you before the MRI procedure begins.

Items such as jewelry, keys, credit cards and electronics cannot be brought into the MRI room. Patients with certain medical implanted devices cannot enter the MRI room. Please inform our staff immediately if you or your child has an implanted medical device. Bringing any information you have regarding your or your child’s medically implanted device is most helpful.

Scheduling sCMR Appointment

After reviewing this information, please call 832-824-9729 to schedule your appointment with the CMR coordinator. To ensure safety, inform the scheduler if your child has any of the following:

• Pacemaker or artificial heart valves
• Metal plates, pins or implants
• Dental appliances (spacers, retainers)
• Ear implants
• Electrical devices (vagal nerve stimulator, or baclofen pumps)
• Shunts

It takes approximately 3-5 days to process the sCMR. The results will be sent to your cardiology provider, who will call you with results. 

We look forward to providing safe and efficient care for your child. 

Cardiac Catheterization

In some coronary anomaly cases, further evaluation is necessary to evaluate the blood flow of the anomalous coronary artery. This is typically needed in patients with AAOCA that involve an intraseptal course, as well as others. Cardiac cath is typically an Outpatient procedure, allowing the child to go home the same day. There are some cases in which further monitoring is necessary, involving an overnight stay in the hospital.

What is cardiac catheterization? 

Cardiac catheterization is a procedure in which small catheters (tubes) and wires are placed in the blood vessels in the groin to access the heart. This gives the team information about pressures and structure of the heart and blood vessels. Specifically, for coronary anomalies, pictures of the coronary arteries will be taken with a contrast dye and special x-ray camera, in addition to measurement of the blood flow inside the coronary artery. This procedure is helpful in measuring pressures within the anomalous coronary artery to evaluate for compromised blood flow.

What is Fractional Flow Reserve? 

Fractional Flow Reserve, or FFR, is a guide wire-based procedure that can accurately measure blood flow through a specific part of the coronary artery. This is often done during the catheterization procedure as well. This gives your cardiologist information about how the blood is flowing through the coronary artery and detect any areas low blood flow.

What to expect during cardiac catheterization

Your child arrives to the holding area prior to the procedure. In this area, your child will be seen by multiple providers from anesthesia and catheterization teams to be sure it is safe to proceed with the test. As the guardian, the risks and benefits of the procedure will be explained to you and signed consent will need to be obtained.

Next, your child will escorted by the anesthesia team to the cardiac catheterization lab. Your child will be given medication to help him/her rest prior to receiving general anesthesia. General anesthesia typically involves a breathing tube to help deliver anesthesia and oxygen during the cath procedure. The patient will undergo the cardiac cath as described above. Following the cardiac cath, all of the catheters will be removed and a pressure bandage will be placed at the access sites. Most often, the breathing tube will be removed by the anesthesia team prior to the patient returning to the recovery area. The physician performing the procedure will meet with you and explain the results. The physician performing the procedure will not have the full plan for the patient until the data is discussed amongst the CAAP team members.

The patient will remain in the recovery area until fully awake from the procedure and no bleeding is observed at the site. Typically patients are discharged home the same day, but occasionally may stay overnight in the inpatient unit.

Before the cardiac catheterization procedure

• You will be called by our nursing team the week prior and day prior to the procedure. They will explain the times needed to fast from food or drink and what time to arrive.
• Attire: Your child will be given a hospital gown to wear.
• Your child may bring a comfort item, like a blanket or stuffed animal.
• We will inform you if any home medications that may interfere with the test, which may need to be held day of the procedure and restarted after the procedure.

Review this information with your child and check for his or her understanding. Assess your child’s anxiety level. If you think your child is anxious, we can have a Child Life Specialist assist in making the process easier. Feel free to ask for Child Life on your arrival.