Fabian Rengier, Presenter: Nothing to Disclose

Tim Weber MD, Abstract Co-Author: Nothing to Disclose

Verena Henninger, Abstract Co-Author: Nothing to Disclose

Hardy Schumacher, Abstract Co-Author: Nothing to Disclose

Dittmar Böckler, Abstract Co-Author: Nothing to Disclose

Hans-Ulrich Kauczor MD, Abstract Co-Author: Research grant, Siemens AG Research grant, Toshiba Corporation Research Consultant, Boehringer Ingelheim GmbH Speakers Bureau, Boehringer Ingelheim GmbH Research grant, Boehringer Ingelheim GmbH Speakers Bureau, Novartis AG

Hendrik Von Tengg-Kobligk MD, Abstract Co-Author: Nothing to Disclose

00030490-DMT et al, Abstract Co-Author: Nothing to Disclose

The endoskeleton of stent grafts e.g. in patients with traumatic aortic rupture without prior history of cardiovascular disease may have to tolerate increased stress due to aortic motion. The purpose of this study was to investigate the stress induced by intrinsic translational displacement of the thoracic aorta in healthy volunteers and to determine clinical predictors for increased dynamics.

61 volunteers (age range/mean 19-82/49±16 years; 28 men, 33 women), divided into two age groups (group A, <50 years, group B ≥50 years), without history of cardiovascular disease underwent 1.5-T-MRI. High-resolution breath-hold TrueFISP imaging was used to acquire ECG-triggered dynamic data sets covering one heart cycle at five locations along the thoracic aorta: A1, mid ascending aorta; A2/A3, mid/distal aortic arch; A4/A5; mid/distal descending thoracic aorta. The maximal displacement of the center of mass (COM) in relation to diastolic aortic diameter was calculated after semi-automatic segmentation of the aortic cross-sections.

The thoracic aorta exhibited significant COM movement at all levels (p<0.001; maximum for age group A/B 41.0/31.5%): Mean±SD at A1-A5 for age group A, 26.8±7.5%, 17.5±5.6%, 12.2±4.7%, 7.9±2.8%, 11.3±3.2%, for age group B, 20.8±4.8%, 10.5±3.7%, 8.3±3.0%, 7.1±3.2%, 8.2±2.9%. The applied model for multiple linear regression was highly significant (p<0.001). Impact of age group, gender, location, and heart rate was statistically significant (p<0.01). Mean arterial blood pressure and BMI had no significant influence on aortic displacement. Men showed significantly lower COM displacement compared to women (p=0.008). COM displacement in age group A was significantly greater compared to age group B (p<0.001). COM displacement significantly decreased from proximal to distal as assessed with post hoc Bonferroni (p<0.05).

In both age groups heart motion and pulsatility induce significant translational displacement of the thoracic aorta at all levels. Intrinsic translational displacement of the thoracic aorta may have relevant consequences for stent graft durability and sealing, especially in young women, and should be considered for endovascular graft design.

Stent grafts are subject to mechanical forces due to intrinsic aortic motion as risk factor for material fatigue. New indications and devices for TEVAR should respect the physiological environment.

Rengier, F, Weber, T, Henninger, V, Schumacher, H, Böckler, D, Kauczor, H, Von Tengg-Kobligk, H, et al, 0, Intrinsic Translational Displacement of the Thoracic Aorta with Implications for Endovascular Stent Graft Design.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8006751.html