1. Aortic Remodeling after Endovascular Repair of the Descending Thoracic Aorta G. William Moser CRNP, Patrick Moeller BS, Thomas Bavaria Jr. BS, Ahmad Zeeshan MD, Joseph Bavaria MD Hospital of the University of Pennsylvania Division of Cardiovascular Surgery

2. Background Thoracic endovascular repair of the aorta (TEVAR) has created new therapeutic issues and challenges Decreased operative mortality, decreased hospital length of stay, decreased mechanical ventilation time, and decreased blood transfusion requirements relative to open repair have led to much increased volume of implantation since the technology was approved TEVAR produces its own challenges, in particular the possibility of endoleaks Occur in up to 29% of patients. Late term development of endoleaks raises the inherent risks of anesthesia, vascular access and hospitalization again face the patient.

3. Changes in Aortic Length The appearance of latent type III endoleaks in patients showing no sign of device migration raises the possibility of changes in aortic length Few studies have specifically targeted analysis of aortic length. – –Previous work has found: Landing zone lengthening in the abdomen 1 A case study noting aortic lengthening in a patient with aortic lengthening-induced aortic valve stenosis 2 We set out to review our descending thoracic aorta (DTA) experience from the perspective of aortic length. 1.Litwinski et al, Journal of Vascular Surgery, 2006; 44: 1176-81. 2.Shah et al, Annals of Thoracic Surgery, 2007; 84: 1010-2

4. Methods A retrospective review of all evaluable CT angiograms (CTA) submitted to M2S (Medical Metrix Solutions, West Lebanon, NH) between January 2000 and August 2009 for 3D modeling of the DTA was conducted. Aortic centerline is computed along 1 mm slices Initial data: 1004 patients with 1844 scansInitial data: 1004 patients with 1844 scans Patients and scans were excluded if:Patients and scans were excluded if: Scans preceded TEVAR, or Patient did not receive TEVARScans preceded TEVAR, or Patient did not receive TEVAR Length of follow-up from first to last scan was less than 300 daysLength of follow-up from first to last scan was less than 300 days Patients with prior open repair of the DTA were excluded, as some portion of their descending aorta was synthetic graft materialPatients with prior open repair of the DTA were excluded, as some portion of their descending aorta was synthetic graft material In cases of reintervention, the longer period of follow-up (between intervention 1 and 2, or after intervention 2) was usedIn cases of reintervention, the longer period of follow-up (between intervention 1 and 2, or after intervention 2) was used

5. Final Cohort 82 patients82 patients 211 scans211 scans Mean length of time from first to last CTA: 897±556 daysMean length of time from first to last CTA: 897±556 days Measurements were taken from centerline slices from celiac artery to subclavian arteryMeasurements were taken from centerline slices from celiac artery to subclavian artery If the subclavian artery was covered, the left common carotid or next proximal vessel was usedIf the subclavian artery was covered, the left common carotid or next proximal vessel was used

6. Annualized Changes in Length: Total Cohort Mean overall change per year: 4.5±7.8mm Mean overall change per year: 4.5±7.8mm Proportion of patients experiencing changes in aortic centerline Proportion of patients experiencing changes in aortic centerline Increase of >10mm per year in 16% (13 patients)Increase of >10mm per year in 16% (13 patients) Increase of 5-10mm per year in 18% (15 patients)Increase of 5-10mm per year in 18% (15 patients) Change of between +5 and -5 mm per year in 60% (49 patients)Change of between +5 and -5 mm per year in 60% (49 patients) Decrease in length of >5mm per year in 6% (5 patients)Decrease in length of >5mm per year in 6% (5 patients)

7. Annualized change in Centerline Length by Surgical Indication Indication for surgeryN Mean (mm) Aneurysm (Fusiform)396.3±7.3 Aneurysm (Saccular)281.6±6.7 Redo TEVAR510.9±10.1 Aortic Dissection92.1±8.3 P value between groups is.014

8. Annualized Change in centerline length by number of implanted stents Number of Stents ImplantedN Mean (mm) 1251.5±7.7 2242.4±5.8 3136.8±9.2 4 or More208.5±8.0 P value between groups is.008

9. Annualized Change in centerline length by Age Age GroupN Mean (mm) <6519-0.2±4.1 65-75336.4±8.9 >75304.8±7.7 P value between groups is.013

10. Conclusions Aortic lengthening occurs in up to 34% of patients who underwent TEVARAortic lengthening occurs in up to 34% of patients who underwent TEVAR Annual length changes of >1cm in 16% of patientsAnnual length changes of >1cm in 16% of patients Lengthening may be more common in older patients, patients with redo TEVAR or fusiform aneurysm, and patients with more than 2 stents implanted