164 - Cardiac magnetic resonance imaging to determine single ventricle function is feasible as a clinical outcome measure, experience from the single ventricle reconstruction trial longitudinal follow up.

Poster Number: 164
Publication Number: 164.101

Jon A. Detterich, Children's Hospital Los Angeles, Los Angeles, CA, United States; Michael Taylor, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States; Timothy Slesnick, Emory University School of Medicine, Atlanta, GA, United States; Michael P. DiLorenzo, Columbia University Medical Center/Morgan Stanley Children’s Hospital, New York, NY, United States; Anthony M. Hlavacek, Medical University of South Carolina College of Medicine, Charleston, SC, United States; Christopher Z. Lam, The Hospital for Sick Children, Toronto, ON, Canada; Shagun Sachdeva, Texas Children's Hospital, Houstin, TX, United States; Sean M. Lang, The Heart Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States; Michael J. Campbell, Duke University School of Medicine, Durham, NC, United States; Jennifer F. Gerardin, Children’S Hospital of Wisconsin, Medical College of Wisconsin, Elmgrove, WI, United States; Kevin K. Whitehead, Childrens Hospital of Philadelphia, Philadelphia, PA, United States; Rahul H. Rathod, Boston Children's Hospital / Harvard Medical School, Boston, MA, United States; Mark Cartoski, NemoursAlfred I. duPont Hospital for Children, Wilmington, DE, United States; Shaji Menon, University of Utah, Salt Lake City, UT, United States; Felicia L. Trachtenberg, HealthCore Inc, Newton, MA, United States; Russell Gongwer, HealthCore, Inc., Waltham, MA, United States; Jane Newburger, Boston Children's Hospital, Waban, MA, United States; Caren Goldberg, University of Michigan Medical School, Ann Arbor, MI, United States; Adam L. Dorfman, University of Michigan Medical School, Ann Arbor, MI, United States

Background: The single ventricle reconstruction trial (SVR) was a randomized prospective trial in congenital heart surgery designed to determine survival advantage of the modified Blalock-Taussig-Thomas shunt (BTTS) vs the right ventricle to pulmonary artery conduit (RVPAS). One aim of the long-term follow-up of this cohort (SVRIII) was to determine if shunt type impacted RV function. Cardiac magnetic resonance imaging (CMR) is the reference standard for volumetric assessment of cardiac function but often requires contrast and/or sedation in the pediatric age group.

Objective: We sought to describe the feasibility of using CMR without the use of sedation or contrast as a focused study to determine single ventricle function.

Design/Methods: The SVRIII protocol included short axis steady state free precession imaging using free-breathing, traditional segmented sequences with signal averaging to limit respiratory motion artifact. Single ventricle systolic function is measured using volumetric analysis of end-diastolic and end-systolic volumes to calculate ejection fraction (EF). Flow quantification was performed in the Fontan, SVC, branch pulmonary arteries and aorta. Cine volumes and vessel flow allow for valve regurgitant fraction analysis. Clinically indicated contrast enhanced CMR was acceptable if it included the required elements.

Results: There were 313 eligible SVRIII participants, 237 participants enrolled, ages 10 to 12.5 years-old, 177/237 (75%) participants underwent CMR. Reasons for not undergoing a CMR exam were a. contraindication (implantable device, other device or metal n=18), b. could not perform awake (required anesthesia, claustrophobia or refusal n=19), or c. other/unknown (n=23). There were 44 (44/177=25%) studies done for clinical indication, 29 (29/177=16%) had contrast. There were 9 (5%) non-diagnostic CMR exams for right ventricle EF and 168 (94%) diagnostic exams. Median exam time was 54 minutes [IQR 40-74], median cine function exam time, including scout images and localizers, 20 minutes [IQR 14-27], and median flow quantification time 18 minutes [IQR 12-25]. There were 69 (69/177=39%) studies noted to have intrathoracic artifacts, the most common being susceptibility artifact from intra-thoracic metal, RF/MRI environment and motion. Not all artifacts cause the exam to be non-diagnostic and sternal wires were not considered artifact unless they obscured anatomic information.Conclusion(s): This study demonstrates that CMR used for assessment of cardiac function in a trial setting is feasible without the use of contrast, general anesthesia or sedation.