Comparison of Duplex Ultrasound and Computed Tomography Surveillance after Endovascular Aneurysm Repair in Determining Proximal Endograft Location

Abstract

Introduction —Color Duplex ultrasound (CDU) is the primary modality for endovascular abdominal aneurysm repair (EVAR) surveillance in our institution. Computed tomography (CT) scan (also known as CT scan or as CTA meaning CT Angiography) is, however, the gold standard to evaluate for endograft migration. We compared duplex ultrasound with CT scan for determination of proximal endograft location. Methods —A retrospective review was performed with the AneuRx® endograft of EVAR patients who had paired CDU and CTA imaging studies within a 3-month interval from January 2009 to June 2010. Patient demographics and distance measurements from the superior mesenteric artery (SMA) to the proximal graft on both CDU and CTA images were obtained. CTA measurements were done by measuring the distance between the SMA and the endograft using digital calipers. CTA patients did not fast. Duplex measurements were obtained in fasted patients by measuring the distance between the SMA and the hyperechoic proximal graft in the sagittal plane on B-mode and color-flow images. Correlation statistics was performed. Results —Twenty-two patients with 26 paired CTA and CDU studies were identified with a mean age of 73.3 years. There were 13 males (59.1%) and 9 females (40.9%). Mean interval between studies was 39.6 days (range, 0–84 days). Mean duplex SMA-endograft measurements were 21.8 ± 6.3 mm and mean CTA measurements were 17.3 ± 7.8 mm. Spearman's correlation coefficient (ρ) between both measurements was 0.44 ( p = 0.012). A subset of patients who had studies within a 1-month interval was also analyzed, with 11 paired studies identified. Mean CTA and duplex measurements were 20.2 ± 9.7 mm and 22.1 ± 7.2 mm respectively (ρ = 0.58; p = 0.031). Conclusion —There is a moderate correlation between CDU and CTA measurements of proximal endograft position after EVAR. Our data suggest that duplex ultrasound is valuable in assessing proximal Aneurx® endograft position and may be so reliable and accurate that it may eventually surpass CTA methodology typically used for assessing endograft migration to become the gold standard.