Objectives: Endovascular aortic aneurysm repair (EVAR) is utilized to treat abdominal aortic aneurysms, while patients with short infrarenal necks can undergo fenestrated EVAR (fEVAR). Previous studies have demonstrated decreased aortic neck dilation for fEVAR compared to EVAR. Sac regression is a marker of success after EVAR, however, little is known regarding changes in sac volumetrics. This study compares aortic sac regression after EVAR vs fEVAR using volumetric analysis. Methods:A retrospective review of prospectively collected data from 120 patients who underwent EVAR was performed. Thirty patients underwent fEVAR (Cook Medical Inc, Bloomington, IN) and 90 patients underwent EVAR (30 each with Endurant, Excluder [Gore, Flagstaff, AZ], and Zenith [Cook]). Demographic data were analyzed. Using three-dimensional reconstruction software, pre- and post-operative aneurysm sac volumes were measured, in addition to aneurysm characteristics. Results: There were no differences in demographic or preoperative comorbidities. Preoperatively, fEVAR had greater percentage of thrombus within the sac by volume compared to EVAR (51.5% vs 39.1%, p=0.0002), and greater overall sac volume (240.8±100.4 vs 188.2±82.4cm3, p=0.005). EVAR patients had greater number of lumbar arteries (7.26±1.68 vs 5.31±1.93, p<0.000001). On postoperative follow-up, fEVAR cases had greater sac regression compared to standard EVAR (-22.75±25.7% vs -5.98±19.66%, p=0.00031). The percentage of sac regression was greater when measured by volume compared to maximum diameter for fEVAR (-22.75±25.7% vs -13.90±15.4%, p=0.01) but not EVAR (-5.98±19.7% vs -4.51±15.2%, p=0.246). Those in the top tertile of percent volume of thrombus (>48.5%) were more likely to experience sac regression (83.8% vs 61.1%, p=0.015). On multivariate analysis, fEVAR was associated with sac regression greater than 10% by volume (OR 4.325, 95% CI 1.346-13.901, p=0.014), while endoleak (OR 0.162, 95% CI 0.055-0.479, p<0.001) and two patent hypogastric arteries (OR 0.066, 95% CI 0.005-0.904, p=0.042) were predictive against. Conclusion:Fenestrated EVAR is associated with greater sac regression compared to EVAR on volumetric analysis. This difference may be attributable to decreased endotension within the aneurysm resulting from less aortic neck dilatation, while the greater proportion of thrombus may be a protective factor from growth. Patients being evaluated for EVAR with borderline neck anatomy should be considered for fEVAR given increased sac regression.
| Preoperative Characteristics | |||
| FEVAR | EVAR | p-value | |
| Total Aortoiliac Outer Wall to Outer Wall Volume , cm3 | 240.8 ± 100.4 | 188.2 ± 82.4 | 0.005 |
| Thrombus Volume, cm3 | 126.0 ± 70.4 | 80.0 ± 68.6 | 0.0027 |
| Aortic Blood Volume, cm3 | 109.2 ± 43.7 | 108.5 ± 39.0 | 0.93456 |
| % thrombus of total volume | 51.5 ± 14.4 | 39.1 ± 15.3 | 0.00022 |
| Maximum aortic diameter, mm | 58.8 ± 10.52 | 53.49 ± 8.79 | 0.0079 |
| Neck length, mm | −2.31 ±11.56 | 29.64 ± 17.50 | <0.001 |
| Seal zone diameter, mm | 26.67 ± 4.01 | 23.58 ± 2.99 | <0.001 |
| Aneurysm length, mm | 110.7 ± 29.2 | 81.3 ± 24.3 | <0.000001 |
| # of hypos patent | 1.86 ± 0.52 | 1.96 ± 0.18 | 0.108 |
| # Lumbars patent | 5.31 ± 1.93 | 7.26 ± 1.68 | <0.000001 |
| # Lumbars >3 mm | 1.00 ± 1.39 | 0.45 ± 0.90 | 0.016 |
| % patent IMA | 79.3% (n=29) | 90.9% | 0.112 |
| Postoperative Characteristics | |||
| Follow-up time, months | 34.77 ± 21.70 | 28.79 ± 23.03 | 0.21 |
| Total Aortic Volume, cm3 | 204.1 ± 82.6 | 188.3 ± 90.7 | 0.40 |
| % Volume change | -22.75 ± 25.7 | -5.98 ± 19.66 | 0.00031 |
| % Sac regression > 5mm | 63.3% | 42.2% | 0.036 |
| % hypo open | 80.0% | 78.9% | 0.867 |
| % Endoleak (all type II) | 26.7% | 31.1% | 0.22 |
