Frank R. Arko1, J Michael Dimaio2, Jeko Madjarov1, Tzvi Nussbaum1, Stephen Llaka1, Timothy Roush1
1Vascular Surgery, Sanger Heart and Vascular Institute, Charlotte, NC; 2University of Texas Southwestern Medical Center, Dallas, TX.
OBJECTIVES: Interactions between components of fenestrated thoracic main stent grafts (MSG) and branch stent grafts (BSG) have not yet been evaluated. This study evaluates the cardiac and respiratory effects on interactions between components in the aortic arch.
METHODS: Between 2006 and 2011, 255 patients underwent TEVAR from 2 institutions. One-hundred seven (42%) required coverage of the left subclavian artery. Sixty (56%) had coverage, 29 (27%) carotid subclavian bypass, and 18 (17%) had a physician-modified endograft for left subclavian artery revascularization. Frames representing the extreme positions of the BSG due to cardiac imposed motion during apnea and through the respiratory cycle were identified. Images were overlaid as layers, using external reference markers common to each image for accurate overlay positioning. BSG’s were traced and magnitudes of horizontal and vertical bulk displacements were quantified to evaluate cardiac (CM) and respiratory (RM) motion [deep inspiration (30 mmHg)]. Relative motion was extracted from bulk motion by comparing displacements at the top and bottom of the BSG.
RESULTS: RM resulted in significant difference in bulk horizontal motion compared to CM for the BSG [4.5+/-0.07 vs. 0.6 +/- 0.63 mm, (p=0.002)]. RM resulted in significant difference in bulk vertical MSG/BSG system [3.8+/-0.07 vs. 0.6+/- 0(p=0.000001)]. RM resulted in significant difference in relative horizontal motion compared to CM for the MSG/BSG system [1.1 +/- 0.07 vs. 0.35+/-0.35 mm, (p=0.0048)]. RM resulted in no significant difference in relative vertical movement compared to CM for the MSG/BSG system [0.5+/-0.14 vs. 0.45+/-0.21 mm, (p=0.07)].
CONCLUSIONS: Respiratory motion adds significant movement to bulk motion in both the vertical and horizontal directions but not to relative motion in humans. The vast majority of cardiac motion is relative motion. Knowledge and assessment of this movement is critical in the design of branched grafts in the arch for long-term success.
AUTHOR DISCLOSURES: F. R. Arko, Nothing to disclose; J. Dimaio, Nothing to disclose; S. Llaka, Nothing to disclose; J. Madjarov, Nothing to disclose; T. Nussbaum, Nothing to disclose; T. Roush, Nothing to disclose.
Posted April 2012