Novel Imaging of Coronary Artery Anomalies to Assess Their Prevalence, the Causes of Clinical Symptoms, and the Risk of Sudden Cardiac Death

Abstract

Downloaded from Circ Cardiovasc ImagingJuly 2014 population with echocardiography or magnetic resonance angiography (MRA) have finally established the conditions for improving our knowledge of the denominator in the risk fraction (the number of cases of SCD divided by the number of persons with CAAs in the general population rather than only in autopsy series). 15,[19][20][21][22] Definitive data about CAA-associated mortality are still lacking, because of a lack of studies based on defined and controlled populations. 13This report attempts to clarify this matter by presenting an overview of more recent and precise approaches to CAA screening, pathophysiology, and clinical evaluation. Systematic Screening for CAAsBecause CAAs are potential causes of severe clinical events in young persons and cannot be identified on the basis of a history and physical examination, various imaging modalities are being tested for their detection. Magnetic Resonance ImagingAt our Center for Coronary Artery Anomalies, recent MRAbased screening of a continuous preliminary series of 1836 students (aged between 11 and 15 years) has finally presented credible data regarding the prevalence of ACAOS. These data are essential for discovering the risk of SCD. Our method is precise, extensive, and related to a general population (the denominator).19 It involves the use of an Achieva 1.5 T A-Series scanner with 32-channel coils (Philips, Amsterdam, the Netherlands) in a mobile unit that has been visiting several public middle schools in Houston. In this ongoing study, we do not use any sedation, contrast medium, or medication.We routinely acquire standard 2-chamber, 4-chamber, and left ventricular outflow tract gradient echo steady-state free precession cine images, followed by a stack of short-axis cine images from the left ventricle, with in-plane resolution of 1.8×1.8 mm and an 8-mm slice with a 2-mm gap for 30 cardiac phases. Coronary MRA images are obtained with a 3-dimensional steady-state free precession electrocardiography-gated echo-navigator sequence with T2 prepreparation. The aortic root and the left ventricular outflow tract are included to ensure identification of the coronary ostia and proximal segments. Acquisition takes a total of 15 to 25 minutes, making this method a much simplified version of cardiac MRI.One foundational finding of this study has been that CAAs are the most frequent high-risk cardiovascular condition for SCD in young persons: indeed, 40% of young people with a high-risk cardiovascular condition have a CAA. 19 Our basic plan was to screen ≈10 000 children for only the types of CAAs capable of causing ischemia and SCD. 13,19 The term ACAOS was refined to include only unusual coronary patterns involving an anomalous aortic origin that the literature suggested could result in a high-risk cardiovascular condition: patterns characterized by an intramural aortic course (previously "located between the aorta and pulmonary artery," or interarterial). 6,10,12,17 Unfortunately, this matter has not been totally resolv...

Should the ECG Be Excluded from Sports Certification Screening? A Typical Case Supports Inclusion

“…Pertinent to this case, the usual precipitant in both apical HCM and R-ACAOS is strenuous exercise-and competitive basketball is recognized as the highest-risk sporting activity in the U.S. 3,4 3) Evaluating functional severity, which differs in individual patients who have a given pathologic condition. 5 During exercise, R-ACAOS causes SCA only by means of ischemia. Ischemia essentially occurs because of the intramural course of the proximal ectopic artery and phasic lateral compression.…”

“…Ischemia essentially occurs because of the intramural course of the proximal ectopic artery and phasic lateral compression. 5 A nuclear adenosine stress test is unlikely to reproduce ischemia by inducing vasodilation. Only a maximal treadmill nuclear stress test can increase cardiac output, aortic dilation, and tachycardia-thereby augmenting the systolic time, during which stenosis worsens in such anomalies.…”

“…Only a maximal treadmill nuclear stress test can increase cardiac output, aortic dilation, and tachycardia-thereby augmenting the systolic time, during which stenosis worsens in such anomalies. 5 Investigators have concluded that intravascular ultrasonographic imaging of the anomalous cross-sectional area is the most reliable test of R-ACAOS severity: in case of SCA, accurately determining the severity of a given defect is essential. 5 This patient's other cardiovascular risk factor was apical HCM, which is more likely than R-ACAOS to cause SCA, ventricular fibrillation, or both, during exertion.…”

“…5 Investigators have concluded that intravascular ultrasonographic imaging of the anomalous cross-sectional area is the most reliable test of R-ACAOS severity: in case of SCA, accurately determining the severity of a given defect is essential. 5 This patient's other cardiovascular risk factor was apical HCM, which is more likely than R-ACAOS to cause SCA, ventricular fibrillation, or both, during exertion. In apical HCM, evaluating individual case severity is even more complex and tentative than in R-ACAOS.…”

“…553 cavity can be extremely high because of midventricular stenosis. 5 Scarring of the apical aneurysm can result from the combination of systolic coronary narrowing or spasm and a simultaneously increased oxygen demand. As Afari and co-authors 1 suggest, dedicated cardiac magnetic resonance studies can clarify details of the apical anatomy, including scarring; however, their published images do not enable such clarification.…”