Risk Factors, Dynamics, and Clinical Consequences of Aortic Neck Dilatation after Standard Endovascular Aneurysm Repair

Abstract

WHAT THIS PAPER ADDS Aortic neck dilatation occurs after endovascular aneurysm repair (EVAR) with self expanding stent grafts but may progress, ultimately exceeding the implanted endograft's diameter, placing patients at risk of abdominal aortic aneurysm rupture. This study suggests that aortic neck dilatation after EVAR is driven by endograft oversizing and radial force. Despite being greater during the first post-operative year, it decreases once the nominal endograft size is reached in most cases. Importantly, baseline aortic neck diameter and endograft characteristics were associated with an increased risk of neck dilatation beyond the nominal graft diameter. The importance of suprarenal stents remains uncertain as the studied suprarenal fixation endografts have greater radial force than their infrarenal counterparts. Additionally, patient selection differences may also have contributed to the reported findings. For patients at risk of excessive neck dilatation and with a long life expectancy, alternative repairs may be preferable for a durable result.Objective: Aortic neck dilatation (AND) occurs after endovascular aneurysm repair (EVAR) with self expanding stent grafts (SESs). Whether it continues, ultimately exceeding the endograft diameter leading to abdominal aortic aneurysm (AAA) rupture, remains uncertain. Dynamics, risk factors, and clinical relevance of AND were investigated after EVAR with standard SESs. Methods: All intact EVAR patients treated from 2000 to 2015 at a tertiary institution were included. Demographic, anatomical, and device related characteristics were investigated as risk factors for AND. Outer to outer diameters were measured at a single standardised aortic level on reconstructed computed tomography (CT) images. Results: A total of 460 patients were included (median follow up 5.2 years, interquartile range [IQR] 3.0, 7.7 years; CT imaging follow up 3.3 years, IQR 1.3, 5.4). Baseline neck diameter was 24 mm (IQR 22, 26) and increased 11.1% (IQR 1.5%, 21.9%) at last CT imaging. Endograft oversizing was 20.0% (IQR 13.6, 28.0). AND was greater during the first year (5.2% [IQR 0, 11.7]) decreasing subsequently (two to four years to 1.4%/year [IQR 0.0, 4.5%], p .001) and was associated with suprarenal fixation endografts (t value ¼ 7.9, p < .001) and oversizing (t value ¼ 4.4, p < .001). AND exceeding the endograft was 3.5% (95% CI 2.2% e 4.8%) and 14.4% (95% CI 11.0% e 17.8%) at five and eight years, respectively. Excessive AND was associated with baseline neck diameter (OR 1.2/mm, 95% CI 1.05 e 1.41) while the Excluder endograft had a protective effect (OR 0.15, 95% CI 0.04 e 0.58). Excessive AND was associated with type 1A endoleak (HR 3.3, 95% CI 1.1 e 9.7) and endograft migration > 5 mm (HR 3.1, 95% CI 1.4 e 6.9). Conclusion: AND after EVAR with SES is associated with endograft oversizing and radial force but decelerates after the first post-operative year. Baseline aortic neck diameter and suprarenal stent bearing endografts were associated with an increased risk of AND beyond nomin...

Proximal seal dilatation following fenestrated endovascular repair for complex abdominal aortic aneurysms

“…13 Our study confirms the development of PSD at this aortic level with a larger sample size, but also demonstrated that proximal seal dilatation following FEVAR decelerates over time. The subsequent deceleration that we found is in concordance with previous studies on infrarenal EVAR 6 , and with Zetterval et al and Qaderi et al, who reported on proximal neck dilatation following FEVAR with physician modified endografts (PMEGs). 12,16 Interestingly, compared with the latest PMEG paper by Zettervall et al, the dilatation rates seemed similar at the measured aortic levels (PMEG at level of SMA: ~18mm at first year vs. ZFEN at level of first covered stent ~17mm at first year).…”

“…We could not perform any direct comparisons between infrarenal PSD after standard EVAR and PSD of the visceral segment after FEVAR due to different stentgrafts used. Nevertheless, the results of the current study and our previous study 6 show quite similar trends, demonstrating PSD fastest in the first year, decelerating over time.…”

“…Especially, as similar to infrarenal EVAR, excessive dilatation may potentially lead to major complications. 6 In the current study we demonstrated that proximal seal dilatation occurs following FEVAR, at a faster rate in the first year and decelerating over time. Stent-graft oversizing and number of target fenestrations were associated with development of >10% PSD at one year.…”

“…5 Apart from natural disease progression, proximal seal dilatation (PSD) J o u r n a l P r e -p r o o f following EVAR has been reported to be associated with the radial force of the stentgraft on the aortic wall and stentgraft oversizing. 6 One of the presumed advantages of FEVAR is the use of a healthier segment of the aorta as proximal sealing zone, which is possibly less prone to dilatation over time, but published data on proximal seal dilatation (PSD) following FEVAR is scarce.…”

“…proximal cuff/Thoracic EVAR [TEVAR], open conversion/other endovascular treatment due to proximal seal-related complications). 6 Outcomes:…”