Surveillance Intervals after Endovascular Aneurysm Repair can be Safely Increased Once More Than 10 mm Aneurysm Sac Regression has been Achieved.

Abstract

The aim of this study was to determine whether patients with ≥ 10 mm aneurysm sac regression are suitable for a less intensive surveillance regimen after endovascular aortic repair (EVAR). In this retrospective single centre study, all patients who underwent elective standard EVAR between 2004 and 2018 were included. All available follow up imaging was assessed retrospectively, and aneurysm sac diameters were compared with the first post-operative computed tomography angiogram. Patients were divided into two groups: patients with < 10 mm aneurysm sac regression and patients with ≥ 10 mm aneurysm sac regression. The primary endpoint was any EVAR related complication, defined as aneurysm rupture, type I or III endoleak, type II endoleak requiring re-intervention, or loss of seal that required intervention. Two hundred and sixty-three patients were included in this analysis, of whom 166 (63.1%) developed ≥ 10 mm aneurysm sac regression in the first four years after EVAR. Among the 166 patients who achieved aneurysm sac regression of ≥ 10 mm, 11 (6.6%) developed an EVAR related complication during a median (interquartile range) follow up of 64 (47, 85) months. The estimated five year freedom from developing an EVAR related complication after reaching ≥ 10 mm sac regression was 94.4% (95% confidence interval 90.9 - 98.1%). If imaging had been postponed by two, three, or five years after ≥ 10 mm aneurysm sac regression, a cumulative delay in diagnosis of EVAR related complications would have occurred in two (1.2%), three (1.8%), and five (3.0%) patients, respectively. Once the aneurysm sac diameter after EVAR had regressed ≥ 10 mm, patients experienced a very low rate of development of EVAR related complications. In these patients, it is safe to increase surveillance intervals.