DOI: 10.21942/uva.21354393.v1
title: ODYSSEUS study

description: Multicentre retrospective cohort study that included 1596 consecutive patients who underwent Endovascular aneurysm repair (EVAR) in 16 hospitals in the Netherlands; 552 undergoing yearly imaging surveillance and 1044 in whom follow-up had been discontinued. We assessed the effect of yearly imaging surveillance in patients in whom the first post-EVAR computed tomography angiography (CTA) showed no abnormalities. Continued yearly imaging surveillance was defined as undergoing at least one imaging study every 16 months during the entire length of the follow-up period. Our hypothesis was that there would be no difference in aneurysm-related mortality between patients with continued and those with discontinued yearly follow-up imaging, and that patients with continued follow-up would undergo more secondary interventions. <br> <strong>Methods and main outcomes </strong> Patients who underwent EVAR between January 2007 and January 2012 were included; survival, imaging studies and secondary interventions were assessed in December 2018. All patients had an intact infrarenal aortic or aortoiliac AAA and their first postoperative CTA was performed within 90 days of EVAR. This CTA had to be free of abnormalities, such as type I-IV endoleak, graft kinking or infection, or limb occlusion. The primary outcome parameters of this study were aneurysm-related mortality and secondary interventions. Secondary outcomes included all-cause mortality, radiological findings during follow-up and aneurysm rupture. <br> <strong>Results </strong> In total, 1596 patients were included with a median (interquartile range) follow-up of 89.1 months (52.6). In the majority of the patients (n = 1178/1596; 74%) no abnormalities were detected on imaging studies during the entire follow-up period. Cox regression analyses were performed to observe which variables were significantly associated with aneurysm-related mortality, secondary interventions and all-cause mortality. American Society of Anesthesiologists (ASA) classification (ASA IV hazard ratio [HR] 3.810, 95% confidence interval [CI] 1.296-11.198), increase in AAA diameter (HR 3.299, 95% CI 1.408-7.729) and continued follow-up (HR 3.611, 95% CI 1.780-7.323) were independently associated with aneurysm-related mortality. Previous variables, and age (HR 1.063 per year, 95% CI 1.052-1.074) were significantly associated with all-cause mortality. No difference in secondary interventions was observed between patients with continued versus discontinued follow-up (89/552; 16% vs. 136/1044; 13%; p=.091). Sensitivity analysis was also performed to correct for misclassification regarding the definition of continued imaging surveillance: patients were classified as continuing to have yearly imaging if they attended at least 80% of their follow-up visits. This resulted in 1018 patients with continued follow-up and 578 patients with discontinued follow-up. Repeated Cox regression (sensitivity) analysis showed that attendance to 80% of the follow-up visits was still significantly associated with all outcomes (aneurysm-related mortality, secondary interventions and all-cause mortality). <br> For access to the dataset please contact author