P-011 - OUTCOMES OF EVAR SURVEILLANCE - A POPULATION-BASED APPROACH TO THE ONGOING DILEMMA

TOPIC:
Abdominal Aortic Aneurysms
AUTHORS:
Dimech A.P. (Faculty of Medicine and Surgery, University of Malta ~ Msida ~ Malta) , Abela M. (Faculty of Medicine and Surgery, University of Malta ~ Msida ~ Malta) , Scicluna R. (Faculty of Medicine and Surgery, University of Malta ~ Msida ~ Malta) , England K. (Department of Health Information and Research, Ministry of Health ~ Pieta' ~ Malta) , Distefano A. (Department of Health Information and Research, Ministry of Health ~ Pieta' ~ Malta) , Mizzi A. (Department of Radiology, Mater Dei Hospital ~ Msida ~ Malta) , Cassar K. (Department of Surgery, Vascular Unit, Mater Dei Hospital ~ Msida ~ Malta) , Grima M.J. (Section of Vascular Surgery, Department of Surgical Sciences, Uppsala University ~ Uppsala ~ Sweden)
Introduction:
Endovascular aneurysm repair (EVAR) is the predominant treatment modality for infrarenal abdominal aortic aneurysm (AAA) repair. Despite the large advances, complications after EVAR are not uncommon and occur in up to one in five patients in the first five years after EVAR. Guidelines by various societies recommend lifelong surveillance in order to prevent complications and late rupture. Frequently patients are not compliant to EVAR surveillance and there is a paucity of evidence as to whether EVAR surveillance is preventing EVAR complications and AAA rupture. The primary aim of this study was to determine the compliance rate of EVAR surveillance in the Maltese population. The secondary aim was to determine all-cause mortality (ACM) and re-intervention rates amongst compliant, non-compliant and lost-to-follow-up patients in this population.
Methods:
The STROBE guidelines were followed for this observational study. Demographic and procedural data of patients undergoing elective standard infra-renal abdominal aortic aneurysm repairs between 1st January 2009 and 31st October 2020 were collected from the Maltese Vascular Registry and official hospital electronic databases. Follow-up was censored on 31st December 2021. Any patient with a temporary national identity number (i.e. non-resident) was excluded from this study. Patients who expired before 12 months had elapsed after EVAR were excluded due to inadequate follow-up opportunity. There has been a shift from yearly CT and/or duplex ultrasound scan (DUS) and/or plain X-rays to yearly DUS with a CT every 5 years. Compliance to EVAR surveillance was defined as uninterrupted DUS and/or CT scan (referred to as medical imaging) every 12 months (+/- 2 months). Non-compliance was defined as non-attendance to one or more 12-monthly imaging surveillance scan with resumption of follow-up after the patient defaulted. Lost to follow-up was defined as initially had regular 12-monthly surveillance imaging which was subsequently abandoned. Imaging data was obtained from the hospital Picture Archiving and Communication System. Analysis of data was carried out using GraphPad Prism version 9.3.1 for MacOS, GraphPad Software, San Diego, California USA, www.graphpad.com.
Results:
155 patients were included in the study (146 males and 9 females). One patient was excluded given the patient was non-resident, and 13 patients were excluded as they passed away before the one-year interval. Age varied between 53-93 years (mean 75 years). 89 patients (57%) were compliant to EVAR surveillance, 39 patients (25%) were non-compliant, and 27 patients (17%) were lost to follow-up. 50% of patients defaulted from EVAR surveillance at six years of follow-up. Up to 31st December 2021, 47 patients (30%) passed away. ACM was least in non-compliant group but at six years, compliant patients had better survival rate than non-compliant and lost-to-follow-up groups (Figure 1). The median survival for non-compliant group was 11 years while the lost-to-follow-up group was six years. Compliant groups had even better survival outcomes if non-compliant and lost-to-follow-up groups were grouped together (Figure 2). 11% (n=17) of compliant patients underwent re-intervention, while 6% (n = 9) non-compliant patients and 2% (n = 3) lost-to-follow-up patients had re-intervention respectively. Five patients (two compliant, one non-compliant and two lost-to-follow-up) had limb extensions; Seven patients (five compliant, two non-compliant) had reintervention for type II endoleak, one compliant patient needed endoanchors for type 1a endoleak, one compliant patient needed explantation of the endograft, while 15 patients needed re-intervention for various other reasons. Five patients needed more than one re-intervention (one was compliant, two non-compliant and two lost-to-follow-up).
Conclusion:
Despite the small size of the country and ease of travel, only 57% of patients in Malta were compliant to EVAR surveillance. Survival was initially better in non-compliant group however six years after EVAR, compliant patients had a better survival rate. Although this study is limited by the small number of patients, the outcomes of EVAR surveillance of this population-based study are similar to contemporary data. This study emphasizes the importance of EVAR surveillance but also continues to stress the need to implement measures to improve EVAR surveillance rates.
References:
Grima MJ, Boufi M, Law M, Jackson D, Stenson K, Patterson B, et al. Editor's Choice - The Implications of Non-compliance to Endovascular Aneurysm Repair Surveillance: A Systematic Review and Meta-analysis. Eur J Vasc Endovasc Surg. 2018; 55:492-502. Grima MJ, Karthikesalingam A, Holt PJ. Multicentre Post-EVAR Surveillance Evaluation Study (EVAR-SCREEN). Eur J Vasc Endovasc Surg. 2019;57:521-526.
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