- Email: [email protected]
Sudden Cardiac Death in a Young Athlete: Imaging Techniques to Evaluate the Etiology
Journal of Radiology Nursing 36 (2017) 24e27
Contents lists available at ScienceDirect
Journal of Radiology Nursing journal homepage: www.radiologynursing.org
Sudden Cardiac Death in a Young Athlete: Imaging Techniques to Evaluate the Etiology Melanie L. Muller, MSN, CRNP-AC * Pediatric Cardiothoracic Surgery, Children's Heart Program, University of Maryland Medical Center, Baltimore, MD
a b s t r a c t Keywords: Anomalous aortic origin of coronary artery Coronary artery imaging Pediatric congenital heart disease Aborted sudden cardiac death
Anomalous aortic origin of the coronary artery (AAOCA) is a rare form of congenital heart disease with varying implications. Although most of the population with this congenital heart defect may remain completely asymptomatic and never know of the diagnosis, the risk of sudden cardiac death among healthy children and young adults during or just after exercise is significant. A previously healthy adolescent female athlete presented to the pediatric intensive care unit after sudden cardiac arrest on the playing field. She was successfully resuscitated, and further imaging revealed a diagnosis of AAOCA. She underwent surgical correction of her defect without complications. AAOCA remains a rare and often undetected form of congenital heart disease based on the asymptomatic nature of the defect; however, with proper imaging, a diagnosis can be made to allow for correct treatment. Copyright © 2016 by the Association for Radiologic & Imaging Nursing.
Introduction Anomalous aortic origin of the coronary artery (AAOCA) is defined as a form of congenital heart disease in which both the right and left main coronary arteries arise from the same side of the aorta, or aortic sinus, either with one common origin or two separate origins (Brothers, Gaynor, Jacobs, Poynter, & Jacobs, 2015). The coronary artery that is arising from the incorrect aortic sinus will then typically have an intramural course within the aortic wall and descend to its proper location. The anomalous coronary artery can also take an interarterial course and lie between the pulmonary artery and aorta, or an intraconal course, and descend through the myocardium. Different variations of this congenital heart defect include anomalous aortic origin of the right coronary artery (AAORCA) arising from the left aortic sinus and anomalous aortic origin of the left coronary artery (AAOLCA) arising from the right aortic sinus (Figure 1). The true prevalence of this congenital heart defect is unknown, simply based on lack of symptomatology among affected patients until they experience sudden cardiac death (SCD); however, studies have shown that approximately 0.1% to 0.7% of the population is affected (Brothers et al., 2015). In addition, studies have shown that the interarterial AAORCA is approximately three to six times more
common than interarterial AAOLCA (Brothers et al., 2015). Of note, AAOCA is a completely different anomaly from anomalous left coronary arising from the pulmonary artery (ALCAPA), which is a form of congenital heart disease that typically presents at 3 to 6 months of life. Symptomatology of ALCAPA typically includes congestive heart failure and left ventricular failure. The risk of SCD in those with AAOCA is greater during or just after exercise when cardiac output and myocardial oxygen demand are at its greatest. Myocardial ischemia because of impaired coronary blood flow through the anomalous coronary artery leads to ventricular arrhythmias and subsequently SCD. Impaired coronary blood flow derives from multiple factors including compression of the anomalous coronary artery itself because of its abnormal course, the typically small ostium of the anomalous coronary artery, and often the acute angle at which it arises from its anomalous origin. Active children and young adults are the most of those who experience SCD (Poynter et al., 2014). In young athletes in the United States who were previously healthy, AAOCA is the second leading cause of SCD because of undiagnosed congenital heart disease (Poynter et al., 2014). The purpose of this article is to present a case report of AAOCA and describe the current recommended imaging for definitive diagnosis to promote optimal management and outcomes. Case report
Conflict of interest: None to report. * Corresponding author: Melanie L. Muller, Pediatric Cardiothoracic Surgery, Children's Heart Program, University of Maryland Medical Center, 110 South Paca Street, 8th Floor, Baltimore, MD 21201. E-mail address: [email protected].
A 14-year-old female with no significant medical history presented to the pediatric intensive care unit (PICU) after cardiac arrest while playing field hockey. According to witnesses and her parents,
http://dx.doi.org/10.1016/j.jradnu.2016.10.011 1546-0843/$36.00/Copyright © 2016 by the Association for Radiologic & Imaging Nursing.
M.L. Muller / Journal of Radiology Nursing 36 (2017) 24e27
25
Figure 1. Portrait depicting the (A) anatomy of anomalous aortic origin of the left coronary artery and (B) the unroofing procedure. Reprinted from The Annals of Thoracic Surgery, 92/3, Kaushal, S., Backer, C.L., Popescu, A.R., Walker, B.L., Russell, H.M., Koenig, P.R., et al., Intramural coronary length correlates with symptoms in patients with anomalous aortic origin of the coronary artery, 986-992, Copyright (2011), with permission from Elsevier.
she had been playing field hockey and suddenly requested to leave the game, complaining of chest pain. She then collapsed and was noted to be pulseless, apneic, and with epistaxis. Cardiopulmonary resuscitation was immediately performed, and on arrival of the emergency medical technicians (EMTs) 8 min later, she was diagnosed with torsades de pointes, a form of ventricular tachycardia. She was successfully converted to a normal sinus rhythm with defibrillation and administration of intravenous lidocaine. She was transported to a hospital emergency department where she was intubated because of respiratory distress and subsequently transferred to the PICU. Initial diagnostic testing for the patient on admission included chest radiograph (Figure 2), the electrocardiogram (ECG) to evaluate her cardiac rhythm, and the echocardiogram. Chest radiograph showed diffuse bilateral lung opacities consistent with pulmonary edema. The initial ECG was consistent with normal sinus rhythm, and the echocardiogram revealed a structurally normal heart with good function although the coronary artery originations were difficult to visualize. On day 2 of her hospitalization, the patient underwent cardiac magnetic resonance imaging (MRI), both with and without contrast to further evaluate cardiac function and revealed an ejection fraction of 67% (normal, 55e70%), normal myocardial wall motion, and no abnormal myocardial perfusion or delayed myocardial enhancement. Unfortunately, artifact from the
Figure 2. Chest radiograph on admission revealing diffuse bilateral lung opacities consistent with diffuse pulmonary edema.
patient's orthodontic hardware prevented accurate assessment of the coronary anatomy. In an effort to assess the patient's coronary artery anatomy, a computed tomography angiography (CTA) of the chest was performed on the third hospital day. The study revealed a limited evaluation of the coronary arteries because of tachycardia. Despite the limitations with the CTA, the right coronary artery was found to arise normally from the right coronary cusp and medial origin, or arising from the middle of the aorta as opposed to the left side, of the left main coronary artery with early branching into the left anterior descending and left circumflex artery. Given the initial cardiac rhythm noted by the EMTs, the diagnosis of prolonged QT syndrome was hypothesized as the etiology of her aborted SCD; however, initial and subsequent ECGs obtained in the PICU showed a normal sinus rhythm with a normal corrected QT interval. QT interval is a measurement within the heart's electrical cycle that represents electrical depolarization and repolarization of the ventricles. Prolonged QT interval represents an increased risk for dysrhythmia, specifically torsades de pointes. She was scheduled for placement of an automatic implantable cardioverter defibrillator in the event of a repeat SCD. Before this procedure, further diagnostic testing was completed to accurately assess the coronary artery anatomy. These subsequent diagnostic studies included a repeat echocardiogram and CTA. The echocardiogram showed the right coronary artery arising normally from the aorta and the left coronary artery arising from the right coronary cusp with an intramural course. This was further confirmed with a gated CTA, which showed AAOLCA arising from the right aortic cusp with an approximate 6 mm intramural course and narrowing of the vessel to approximately 1 mm (Figure 3). Based on these findings, the patient underwent unroofing of the intramural portion of her AAOLCA without complications. This procedure removes the aortic wall tissue overlying the coronary artery allowing the coronary artery to fully expand and provide myocardial oxygenation during times of high demand (Kaushal et al., 2011). There was no reimplantation of the anomalous coronary artery. Before discharge to home on postoperative day 5, the patient underwent a follow-up echocardiogram, which showed prograde (forward) blood flow through the AAOLCA and normal biventricular function. At subsequent pediatric cardiology follow-up appointments, the patient had repeat imaging including CTA and nuclear medicine myocardial perfusion single-photon emission computed tomography (SPECT). The CTA showed patent coronary arteries with the origin of the left main measuring approximately 3 mm by 2 mm in diameter. The exercise myocardial perfusion SPECT
26
M.L. Muller / Journal of Radiology Nursing 36 (2017) 24e27
Figure 3. Computed tomography angiography showing take off of left main coronary artery after its intramural course with early branching into the left anterior descending and left circumflex artery. AAOLCA ¼ Anomalous aortic origin of the left coronary artery.
displayed no evidence of myocardial ischemia or prior infarction, normal regional wall motion, and systolic function with a left ventricular ejection fraction of greater than 70%. The patient has since returned to playing field hockey and has reported no cardiac symptomatology, including chest pain, palpitations, or shortness of breath. Discussion As discussed previously, it is difficult to determine the true number of people affected with this specific type of congenital heart disease simply because of the lack of symptoms. Because this type of congenital heart disease cannot be detected with a routine history and physical examination, the diagnosis is typically made after the patient experiences symptoms such as chest pain with exertion, syncope, dysrhythmia, and/or aborted SCD. In some cases, the diagnosis is made postmortem. According to Maron, Doerer,
Haas, Tierney, and Mueller (2009), AAOCA accounted for 17% of SCDs in athletes over a 27-year period. This statistic is also difficult to accurately obtain because of lack of autopsy after death. Imaging modalities used for diagnosis of AAOCA include echocardiogram, stress echocardiogram, cardiac MRI, and CTA. Transthoracic echocardiogram (TTE) remains the first imaging modality used to attempt to diagnose AAOCA. TTE is without risk to the patient; however, depending on the patient's age, compliance with the examination may be difficult and subsequently inhibit the ability to visualize the coronary arteries and their origination. Although this remains the initial imaging modality, the diagnosis of AAOCA by TTE remains extremely low at approximately 0.09% to 0.17% (Thankavel, Lemler, & Ramaciotti, 2015). Even if the diagnosis is made using TTE, typically additional imaging modalities are used to confirm the diagnosis. Transesophageal echocardiogram is typically not used because of its invasiveness and cost (Angelini, 2014).
M.L. Muller / Journal of Radiology Nursing 36 (2017) 24e27
Another imaging modality used to either diagnose AAOCA or confirm the diagnosis is cardiac MRI. This noninvasive radiationfree imaging modality has proven to provide detailed images of the heart, great vessels, and coronary arteries; however, it does carry risks, specifically for younger children. In an effort to obtain the needed images, the patient must be able to stay still in an enclosed space for a longer period. Young children obviously do not have the developmental capacity to do this; therefore, they require moderate sedation or even general anesthesia to undergo the imaging. Additional barriers to this imaging modality include the need for a contrast agent, artifact from metal elsewhere in the body, physiologically faster heart rates, and difficulty compensating for respiratory motion. Despite these barriers, cardiac MRI is recommended by the American Heart Association as the next step in diagnosing coronary anomalies in children (Mosca & Phoon, 2016). CTA has proven to be the imaging modality with the most precision in identifying cardiac anatomic abnormalities and was adopted by the American College of Cardiology/American Heart Association in the guidelines for diagnosing and managing adults with congenital heart disease, specifically congenital coronary anomalies (Amado et al., 2016). Although this modality is a much shorter duration than cardiac MRI, it does possess risks in that it does require ionizing radiation and the injection of a contrast agent. In addition, CTA lacks the ability to image soft tissue, therefore making it difficult to assess the coronary artery in relationship to its surrounding tissue (Tangcharoen et al., 2011). Once the diagnosis of AAOCA has been made, the need for surgical repair is dependent on the patient's specific lesion. A patient with symptomatic AAORCA or AAOLCA requires surgical repair and restriction from competitive sports before surgery. The restriction from competitive sports remains in place for at least 3 months after surgery and after successfully completing an exercise stress test (Van Hare et al., 2015). Patients with incidental finding of asymptomatic AAOLCA also require repair because of the higher risk of SCD typically after 10 years of age when they become engaged in competitive sports (Van Hare et al., 2015). Controversy exists regarding the repair of patients with asymptomatic AAORCA. For this specific lesion, multiple factors are taken into consideration when deciding on surgical repair including the patient's desire to engage in competitive sports and the anatomic features of the coronary artery such as size of the opening of the coronary artery and length of the intramural portion (Van Hare et al., 2015). In a retrospective study performed by Kaushal et al. (2011), it was demonstrated that intramural length of the coronary artery correlated with severity of patient symptoms. The need for automated external defibrillators It is estimated that approximately 1 in 70 high schools through the United States will have someone experience SCD on their campus with about half of the victims being students and student athletes (Drezner, Toresdahl, Rao, Huszti, & Harmon, 2013). The availability of an automated external defibrillator (AED) at schools and athletic facilities has increased SCD survival to 80% versus 50% if
27
the AED is brought from a responding EMT unit (Drezner et al., 2013). Unfortunately, barriers to AED availability at these locations exist including lack of financial resources and lack of legislation mandating access despite several national guidelines suggesting their availability. Conclusion Although AAOCA is not a highly prevalent form of congenital heart disease, if undiagnosed or not properly diagnosed, patients may experience significant adverse consequences including SCD. Diagnosing AAOCA requires utilization of proper imaging techniques while taking into account individual patient factors as well as risks and benefits. TTE remains the initial imaging modality used in the diagnosis of AAOCA followed by either a cardiac MRI or a CTA to confirm the diagnosis. References Amado, J., Carvalho, M., Ferreira, W., Gago, P., Gama, V., & Bettencourt, N. (2016). Coronary arteries anomalous aortic origin on a computed tomography angiography population: Prevalence, characteristics and clinical impact. The International Journal of Cardiovascular Imaging, 32, 983-990. Angelini, P. (2014). Novel imaging of coronary artery anomalies to assess their prevalence, the causes of clinical symptoms, and the risk of sudden cardiac death. Circulation: Cardiovascular Imaging, 7, 747-754. Brothers, J.A., Gaynor, J.W., Jacobs, J.P., Poynter, J.A., & Jacobs, M.L. (2015). The congenital heart surgeons' society registry of anomalous aortic origin of a coronary artery: An update. Cardiology in the Young, 25, 1567-1571. Drezner, J.A., Toresdahl, B.G., Rao, A.L., Huszti, E., & Harmon, K.G. (2013). Outcomes from sudden cardiac arrest in US high schools: A 2-year prospective study from the national registry for AED use in sports. British Journal of Sports Medicine, 47(18), 1179-1183. Kaushal, S., Backer, C.L., Popescu, A.R., Walker, B.L., Russell, H.M., Koenig, P.R., et al. (2011). Intramural coronary length correlates with symptoms in patients with anomalous aortic origin of the coronary artery. The Annals of Thoracic Surgery, 92, 986-992. Maron, B.J., Doerer, J.J., Haas, T.S., Tierney, D.M., & Mueller, F.O. (2009). Sudden deaths in young competitive athletes: Analysis of 1866 deaths in the United States, 1980-2006. Circulation, 119, 1085-1092. Mosca, R.S., & Phoon, C.K.L. (2016). Anomalous aortic origin of a coronary artery is not always a surgical disease. Seminars in Thoracic and Cardiovascular Surgery: Pediatric Cardiac Surgery Annual, 19(1), 30-36. Poynter, J.A., Williams, W.G., McIntyre, S., Brothers, J.A., Jacobs, M.L., & the Congenital Heart Surgeons Society AAOCA Working Group. (2014). Anomalous aortic origin of a coronary artery: A report from the congenital heart surgeons society registry. World Journal for Pediatric & Congenital Heart Surgery, 5(1), 2230. Tangcharoen, T., Bell, A., Hegde, S., Hussain, T., Beerbaum, T., Schaeffter, T., et al. (2011). Detection of coronary artery anomalies in infants and children with congenital heart disease by using MR imaging. Radiology, 259(1), 240-274. Thankavel, P.P., Lemler, M.S., & Ramaciotti, C. (2015). Utility and importance of new echocardiographic screening methods in diagnosis of anomalous coronary origins in the pediatric population: Assessment of quality improvement. Pediatric Cardiology, 36(1), 120-125. Van Hare, G.F., Ackerman, M.J., Evangelista, J.A., Kovacs, R.J., Myerburg, R.J., Shafer, K.M., et al., American Heart Association Electrocardiography and Arrhythmias Committee of Council on Clinical Cardiology, Council on Cardiovascular Disease in Young, Council on Cardiovascular and Stroke Nursing, Council on Functional Genomics and Translational Biology, and American College of Cardiology. (2015). Eligibility and disqualification recommendations for competitive athletes with cardiovascular abnormalities: Task force 4: Congenital heart disease: A scientific statement from the American Heart Association and American College of Cardiology. Circulation, 132(22), e281-e291.
Contents lists available at ScienceDirect
Journal of Radiology Nursing journal homepage: www.radiologynursing.org
Sudden Cardiac Death in a Young Athlete: Imaging Techniques to Evaluate the Etiology Melanie L. Muller, MSN, CRNP-AC * Pediatric Cardiothoracic Surgery, Children's Heart Program, University of Maryland Medical Center, Baltimore, MD
a b s t r a c t Keywords: Anomalous aortic origin of coronary artery Coronary artery imaging Pediatric congenital heart disease Aborted sudden cardiac death
Anomalous aortic origin of the coronary artery (AAOCA) is a rare form of congenital heart disease with varying implications. Although most of the population with this congenital heart defect may remain completely asymptomatic and never know of the diagnosis, the risk of sudden cardiac death among healthy children and young adults during or just after exercise is significant. A previously healthy adolescent female athlete presented to the pediatric intensive care unit after sudden cardiac arrest on the playing field. She was successfully resuscitated, and further imaging revealed a diagnosis of AAOCA. She underwent surgical correction of her defect without complications. AAOCA remains a rare and often undetected form of congenital heart disease based on the asymptomatic nature of the defect; however, with proper imaging, a diagnosis can be made to allow for correct treatment. Copyright © 2016 by the Association for Radiologic & Imaging Nursing.
Introduction Anomalous aortic origin of the coronary artery (AAOCA) is defined as a form of congenital heart disease in which both the right and left main coronary arteries arise from the same side of the aorta, or aortic sinus, either with one common origin or two separate origins (Brothers, Gaynor, Jacobs, Poynter, & Jacobs, 2015). The coronary artery that is arising from the incorrect aortic sinus will then typically have an intramural course within the aortic wall and descend to its proper location. The anomalous coronary artery can also take an interarterial course and lie between the pulmonary artery and aorta, or an intraconal course, and descend through the myocardium. Different variations of this congenital heart defect include anomalous aortic origin of the right coronary artery (AAORCA) arising from the left aortic sinus and anomalous aortic origin of the left coronary artery (AAOLCA) arising from the right aortic sinus (Figure 1). The true prevalence of this congenital heart defect is unknown, simply based on lack of symptomatology among affected patients until they experience sudden cardiac death (SCD); however, studies have shown that approximately 0.1% to 0.7% of the population is affected (Brothers et al., 2015). In addition, studies have shown that the interarterial AAORCA is approximately three to six times more
common than interarterial AAOLCA (Brothers et al., 2015). Of note, AAOCA is a completely different anomaly from anomalous left coronary arising from the pulmonary artery (ALCAPA), which is a form of congenital heart disease that typically presents at 3 to 6 months of life. Symptomatology of ALCAPA typically includes congestive heart failure and left ventricular failure. The risk of SCD in those with AAOCA is greater during or just after exercise when cardiac output and myocardial oxygen demand are at its greatest. Myocardial ischemia because of impaired coronary blood flow through the anomalous coronary artery leads to ventricular arrhythmias and subsequently SCD. Impaired coronary blood flow derives from multiple factors including compression of the anomalous coronary artery itself because of its abnormal course, the typically small ostium of the anomalous coronary artery, and often the acute angle at which it arises from its anomalous origin. Active children and young adults are the most of those who experience SCD (Poynter et al., 2014). In young athletes in the United States who were previously healthy, AAOCA is the second leading cause of SCD because of undiagnosed congenital heart disease (Poynter et al., 2014). The purpose of this article is to present a case report of AAOCA and describe the current recommended imaging for definitive diagnosis to promote optimal management and outcomes. Case report
Conflict of interest: None to report. * Corresponding author: Melanie L. Muller, Pediatric Cardiothoracic Surgery, Children's Heart Program, University of Maryland Medical Center, 110 South Paca Street, 8th Floor, Baltimore, MD 21201. E-mail address: [email protected].
A 14-year-old female with no significant medical history presented to the pediatric intensive care unit (PICU) after cardiac arrest while playing field hockey. According to witnesses and her parents,
http://dx.doi.org/10.1016/j.jradnu.2016.10.011 1546-0843/$36.00/Copyright © 2016 by the Association for Radiologic & Imaging Nursing.
M.L. Muller / Journal of Radiology Nursing 36 (2017) 24e27
25
Figure 1. Portrait depicting the (A) anatomy of anomalous aortic origin of the left coronary artery and (B) the unroofing procedure. Reprinted from The Annals of Thoracic Surgery, 92/3, Kaushal, S., Backer, C.L., Popescu, A.R., Walker, B.L., Russell, H.M., Koenig, P.R., et al., Intramural coronary length correlates with symptoms in patients with anomalous aortic origin of the coronary artery, 986-992, Copyright (2011), with permission from Elsevier.
she had been playing field hockey and suddenly requested to leave the game, complaining of chest pain. She then collapsed and was noted to be pulseless, apneic, and with epistaxis. Cardiopulmonary resuscitation was immediately performed, and on arrival of the emergency medical technicians (EMTs) 8 min later, she was diagnosed with torsades de pointes, a form of ventricular tachycardia. She was successfully converted to a normal sinus rhythm with defibrillation and administration of intravenous lidocaine. She was transported to a hospital emergency department where she was intubated because of respiratory distress and subsequently transferred to the PICU. Initial diagnostic testing for the patient on admission included chest radiograph (Figure 2), the electrocardiogram (ECG) to evaluate her cardiac rhythm, and the echocardiogram. Chest radiograph showed diffuse bilateral lung opacities consistent with pulmonary edema. The initial ECG was consistent with normal sinus rhythm, and the echocardiogram revealed a structurally normal heart with good function although the coronary artery originations were difficult to visualize. On day 2 of her hospitalization, the patient underwent cardiac magnetic resonance imaging (MRI), both with and without contrast to further evaluate cardiac function and revealed an ejection fraction of 67% (normal, 55e70%), normal myocardial wall motion, and no abnormal myocardial perfusion or delayed myocardial enhancement. Unfortunately, artifact from the
Figure 2. Chest radiograph on admission revealing diffuse bilateral lung opacities consistent with diffuse pulmonary edema.
patient's orthodontic hardware prevented accurate assessment of the coronary anatomy. In an effort to assess the patient's coronary artery anatomy, a computed tomography angiography (CTA) of the chest was performed on the third hospital day. The study revealed a limited evaluation of the coronary arteries because of tachycardia. Despite the limitations with the CTA, the right coronary artery was found to arise normally from the right coronary cusp and medial origin, or arising from the middle of the aorta as opposed to the left side, of the left main coronary artery with early branching into the left anterior descending and left circumflex artery. Given the initial cardiac rhythm noted by the EMTs, the diagnosis of prolonged QT syndrome was hypothesized as the etiology of her aborted SCD; however, initial and subsequent ECGs obtained in the PICU showed a normal sinus rhythm with a normal corrected QT interval. QT interval is a measurement within the heart's electrical cycle that represents electrical depolarization and repolarization of the ventricles. Prolonged QT interval represents an increased risk for dysrhythmia, specifically torsades de pointes. She was scheduled for placement of an automatic implantable cardioverter defibrillator in the event of a repeat SCD. Before this procedure, further diagnostic testing was completed to accurately assess the coronary artery anatomy. These subsequent diagnostic studies included a repeat echocardiogram and CTA. The echocardiogram showed the right coronary artery arising normally from the aorta and the left coronary artery arising from the right coronary cusp with an intramural course. This was further confirmed with a gated CTA, which showed AAOLCA arising from the right aortic cusp with an approximate 6 mm intramural course and narrowing of the vessel to approximately 1 mm (Figure 3). Based on these findings, the patient underwent unroofing of the intramural portion of her AAOLCA without complications. This procedure removes the aortic wall tissue overlying the coronary artery allowing the coronary artery to fully expand and provide myocardial oxygenation during times of high demand (Kaushal et al., 2011). There was no reimplantation of the anomalous coronary artery. Before discharge to home on postoperative day 5, the patient underwent a follow-up echocardiogram, which showed prograde (forward) blood flow through the AAOLCA and normal biventricular function. At subsequent pediatric cardiology follow-up appointments, the patient had repeat imaging including CTA and nuclear medicine myocardial perfusion single-photon emission computed tomography (SPECT). The CTA showed patent coronary arteries with the origin of the left main measuring approximately 3 mm by 2 mm in diameter. The exercise myocardial perfusion SPECT
26
M.L. Muller / Journal of Radiology Nursing 36 (2017) 24e27
Figure 3. Computed tomography angiography showing take off of left main coronary artery after its intramural course with early branching into the left anterior descending and left circumflex artery. AAOLCA ¼ Anomalous aortic origin of the left coronary artery.
displayed no evidence of myocardial ischemia or prior infarction, normal regional wall motion, and systolic function with a left ventricular ejection fraction of greater than 70%. The patient has since returned to playing field hockey and has reported no cardiac symptomatology, including chest pain, palpitations, or shortness of breath. Discussion As discussed previously, it is difficult to determine the true number of people affected with this specific type of congenital heart disease simply because of the lack of symptoms. Because this type of congenital heart disease cannot be detected with a routine history and physical examination, the diagnosis is typically made after the patient experiences symptoms such as chest pain with exertion, syncope, dysrhythmia, and/or aborted SCD. In some cases, the diagnosis is made postmortem. According to Maron, Doerer,
Haas, Tierney, and Mueller (2009), AAOCA accounted for 17% of SCDs in athletes over a 27-year period. This statistic is also difficult to accurately obtain because of lack of autopsy after death. Imaging modalities used for diagnosis of AAOCA include echocardiogram, stress echocardiogram, cardiac MRI, and CTA. Transthoracic echocardiogram (TTE) remains the first imaging modality used to attempt to diagnose AAOCA. TTE is without risk to the patient; however, depending on the patient's age, compliance with the examination may be difficult and subsequently inhibit the ability to visualize the coronary arteries and their origination. Although this remains the initial imaging modality, the diagnosis of AAOCA by TTE remains extremely low at approximately 0.09% to 0.17% (Thankavel, Lemler, & Ramaciotti, 2015). Even if the diagnosis is made using TTE, typically additional imaging modalities are used to confirm the diagnosis. Transesophageal echocardiogram is typically not used because of its invasiveness and cost (Angelini, 2014).
M.L. Muller / Journal of Radiology Nursing 36 (2017) 24e27
Another imaging modality used to either diagnose AAOCA or confirm the diagnosis is cardiac MRI. This noninvasive radiationfree imaging modality has proven to provide detailed images of the heart, great vessels, and coronary arteries; however, it does carry risks, specifically for younger children. In an effort to obtain the needed images, the patient must be able to stay still in an enclosed space for a longer period. Young children obviously do not have the developmental capacity to do this; therefore, they require moderate sedation or even general anesthesia to undergo the imaging. Additional barriers to this imaging modality include the need for a contrast agent, artifact from metal elsewhere in the body, physiologically faster heart rates, and difficulty compensating for respiratory motion. Despite these barriers, cardiac MRI is recommended by the American Heart Association as the next step in diagnosing coronary anomalies in children (Mosca & Phoon, 2016). CTA has proven to be the imaging modality with the most precision in identifying cardiac anatomic abnormalities and was adopted by the American College of Cardiology/American Heart Association in the guidelines for diagnosing and managing adults with congenital heart disease, specifically congenital coronary anomalies (Amado et al., 2016). Although this modality is a much shorter duration than cardiac MRI, it does possess risks in that it does require ionizing radiation and the injection of a contrast agent. In addition, CTA lacks the ability to image soft tissue, therefore making it difficult to assess the coronary artery in relationship to its surrounding tissue (Tangcharoen et al., 2011). Once the diagnosis of AAOCA has been made, the need for surgical repair is dependent on the patient's specific lesion. A patient with symptomatic AAORCA or AAOLCA requires surgical repair and restriction from competitive sports before surgery. The restriction from competitive sports remains in place for at least 3 months after surgery and after successfully completing an exercise stress test (Van Hare et al., 2015). Patients with incidental finding of asymptomatic AAOLCA also require repair because of the higher risk of SCD typically after 10 years of age when they become engaged in competitive sports (Van Hare et al., 2015). Controversy exists regarding the repair of patients with asymptomatic AAORCA. For this specific lesion, multiple factors are taken into consideration when deciding on surgical repair including the patient's desire to engage in competitive sports and the anatomic features of the coronary artery such as size of the opening of the coronary artery and length of the intramural portion (Van Hare et al., 2015). In a retrospective study performed by Kaushal et al. (2011), it was demonstrated that intramural length of the coronary artery correlated with severity of patient symptoms. The need for automated external defibrillators It is estimated that approximately 1 in 70 high schools through the United States will have someone experience SCD on their campus with about half of the victims being students and student athletes (Drezner, Toresdahl, Rao, Huszti, & Harmon, 2013). The availability of an automated external defibrillator (AED) at schools and athletic facilities has increased SCD survival to 80% versus 50% if
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the AED is brought from a responding EMT unit (Drezner et al., 2013). Unfortunately, barriers to AED availability at these locations exist including lack of financial resources and lack of legislation mandating access despite several national guidelines suggesting their availability. Conclusion Although AAOCA is not a highly prevalent form of congenital heart disease, if undiagnosed or not properly diagnosed, patients may experience significant adverse consequences including SCD. Diagnosing AAOCA requires utilization of proper imaging techniques while taking into account individual patient factors as well as risks and benefits. TTE remains the initial imaging modality used in the diagnosis of AAOCA followed by either a cardiac MRI or a CTA to confirm the diagnosis. References Amado, J., Carvalho, M., Ferreira, W., Gago, P., Gama, V., & Bettencourt, N. (2016). Coronary arteries anomalous aortic origin on a computed tomography angiography population: Prevalence, characteristics and clinical impact. The International Journal of Cardiovascular Imaging, 32, 983-990. Angelini, P. (2014). Novel imaging of coronary artery anomalies to assess their prevalence, the causes of clinical symptoms, and the risk of sudden cardiac death. Circulation: Cardiovascular Imaging, 7, 747-754. Brothers, J.A., Gaynor, J.W., Jacobs, J.P., Poynter, J.A., & Jacobs, M.L. (2015). The congenital heart surgeons' society registry of anomalous aortic origin of a coronary artery: An update. Cardiology in the Young, 25, 1567-1571. Drezner, J.A., Toresdahl, B.G., Rao, A.L., Huszti, E., & Harmon, K.G. (2013). Outcomes from sudden cardiac arrest in US high schools: A 2-year prospective study from the national registry for AED use in sports. British Journal of Sports Medicine, 47(18), 1179-1183. Kaushal, S., Backer, C.L., Popescu, A.R., Walker, B.L., Russell, H.M., Koenig, P.R., et al. (2011). Intramural coronary length correlates with symptoms in patients with anomalous aortic origin of the coronary artery. The Annals of Thoracic Surgery, 92, 986-992. Maron, B.J., Doerer, J.J., Haas, T.S., Tierney, D.M., & Mueller, F.O. (2009). Sudden deaths in young competitive athletes: Analysis of 1866 deaths in the United States, 1980-2006. Circulation, 119, 1085-1092. Mosca, R.S., & Phoon, C.K.L. (2016). Anomalous aortic origin of a coronary artery is not always a surgical disease. Seminars in Thoracic and Cardiovascular Surgery: Pediatric Cardiac Surgery Annual, 19(1), 30-36. Poynter, J.A., Williams, W.G., McIntyre, S., Brothers, J.A., Jacobs, M.L., & the Congenital Heart Surgeons Society AAOCA Working Group. (2014). Anomalous aortic origin of a coronary artery: A report from the congenital heart surgeons society registry. World Journal for Pediatric & Congenital Heart Surgery, 5(1), 2230. Tangcharoen, T., Bell, A., Hegde, S., Hussain, T., Beerbaum, T., Schaeffter, T., et al. (2011). Detection of coronary artery anomalies in infants and children with congenital heart disease by using MR imaging. Radiology, 259(1), 240-274. Thankavel, P.P., Lemler, M.S., & Ramaciotti, C. (2015). Utility and importance of new echocardiographic screening methods in diagnosis of anomalous coronary origins in the pediatric population: Assessment of quality improvement. Pediatric Cardiology, 36(1), 120-125. Van Hare, G.F., Ackerman, M.J., Evangelista, J.A., Kovacs, R.J., Myerburg, R.J., Shafer, K.M., et al., American Heart Association Electrocardiography and Arrhythmias Committee of Council on Clinical Cardiology, Council on Cardiovascular Disease in Young, Council on Cardiovascular and Stroke Nursing, Council on Functional Genomics and Translational Biology, and American College of Cardiology. (2015). Eligibility and disqualification recommendations for competitive athletes with cardiovascular abnormalities: Task force 4: Congenital heart disease: A scientific statement from the American Heart Association and American College of Cardiology. Circulation, 132(22), e281-e291.