Improved Flow Modeling using a Modified Aortic Arch Advancement for Neonatal Arch Hypoplasia
Joseph R. Nellis1, Timothy K. Chung2, Nandita Agarwal1, Jose E. Torres3, Sarah E. Holgren1, Madhavan L. Raghavan2, Joseph W. Turek4.
1University of Iowa Carver College of Medicine, Iowa City, IA, USA, 2University of Iowa College of Engineering, Iowa City, IA, USA, 3Yavapai Regional Medical Center, Prescott, AZ, USA, 4University of Iowa Children's Hospital, Iowa City, IA, USA.
OBJECTIVE: Numerous surgical approaches regarding aortic arch advancement for neonatal arch hypoplasia have been described. These repairs can be classified into two categories - those that incorporate a patch and those that do not. The decision between repairs remains largely experiential, rather than empirical, due to the limited number of reported outcomes. We report early outcomes from neonates undergoing aortic arch advancement with an anterior patch (+/- performed without cardioplegic arrest) and our experience using computational flow modeling to better understand the hemodynamic consequences associated with these repairs.
METHODS: A single institution review of neonates undergoing aortic arch advancement with anterior patch during 2014. Anatomical, perioperative and follow-up data were collected. Post-operative three-dimensional magnetic resonance imaging aortic arch reconstructions were used to generate a computational flow model of the repair. Parameters of the anterior patch were manipulated virtually to create idealized direct end-to-side and modified anterior patch models. Hemodynamic changes were recorded. Results were reported as median (IQR).
RESULTS: Ten neonates underwent modified aortic arch advancement. No hemodynamically significant gradients or velocities were observed at a median follow-up of 282 (109, 454) days. Higher peak systolic velocities across the transverse arch were observed in the direct end-to-side flow model relative to the anterior patch model (3.16 m/s vs. 2.54 m/s)(Figure 1A and 1B respectively). Distally, these same velocities depreciated to a greater extent in the direct end-to-side model (p-value 0.0026). Asymmetrical flow was observed throughout the direct end-to-side model, while concentric lamellar flow was observed in the descending aorta of the anterior patch model. Further pattern analysis is being performed.
CONCLUSIONS: Early outcomes following the use of an anterior patch for neonatal hypoplastic aortic arch repair show favorable hemodynamic outcomes. Furthermore, continuous coronary perfusion as part of the modification did not diminish the quality of the repair as assessed by postoperative gradients.
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