Redefining postoperative surveillance after endovascular aneurysm repair: recommendations based on 5-year follow-up in the US Zenith multicenter trial.

INTRODUCTION: Recommended postoperative surveillance after endovascular aneurysm repair (EVAR) includes serial contrast-enhanced CT scans. The cumulative deleterious effect on renal function, radiation exposure, and significant cost of this surveillance regimen are all problematic. However, there are scant data to support modulation of current post-EVAR surveillance regimens.
METHODS: The study comprised patients who underwent EVAR as part of the prospective multicenter pivotal (phase II) and continued-access (phase III) US Zenith Endovascular (Cook, Bloomington, Ind) graft trials. A core lab prospectively recorded patient data. A composite aneurysm-related morbidity (ARM) variable was calculated to include aneurysm rupture, open conversion, any secondary intervention, limb thrombosis, migration, renal morbidity, or aneurysm-related death. The long-term freedom from ARM as a function of the presence or cumulative absence of any endoleak at 1, 6, and 12 months was analyzed. The potential additive predictive utility of aneurysm sac shrinkage (>/=5 mm) was assessed at 12 months. The instructions for use for aortic neck anatomy (>/=15 mm length, 18 to 28 mm diameter, </=60 degrees angulation) were followed.
RESULTS: EVAR was done in 739 patients (mean follow-up, 29.9 +/- 17.1 months). Freedom from endoleak at 1 month was highly predictive (P < .001) of reduced ARM: freedom from ARM was 92.3%, 89.8%, 85.2%, 83.1% and 83.1 % at 1, 2, 3, 4, and 5 years, respectively, in patients without endoleak (83.1%) and 75%, 67.1%, 61.5%, 55.9%, and 55.9% in patients with endoleak (16.9%). Cumulative absence of endoleak at 1 year (77.6%) was associated with 94%, 91.5%, 88.1%, 85.8%, and 85.8% 1- to 5-year freedom from ARM vs 73.3%, 66.7%, 56.6%, 52.5%, and 52.5% in patients with endoleak </=1 year (22.4%), P < .001. In patients without endoleak at 12 months, the subsequent risk of any ARM was 8.2% (5-year risk, 14.2%; 1-year risk, 6.0%). In patients with significant sac shrinkage (>/=5 mm) and cumulative absence of endoleak at 12 months, the subsequent risk of an ARM was 5.3% (5-year risk, 11.1%; 1-year risk, 5.8%).
CONCLUSIONS: Absence of endoleak at 30 and 365 days predicted greatly improved long-term freedom from ARM compared with early endoleak. A new EVAR surveillance regimen is recommended that modulates the intensity and frequency of postoperative imaging based on these early outcomes. In patients without early endoleak, the 6-month surveillance is eliminated, and aortic ultrasound is suggested for long-term surveillance >1 year. In most patients, this reduced surveillance regimen would be appropriate and could improve patient safety by reducing the cumulative deleterious effects of intravenous contrast and radiation exposure while also reducing health care costs. These subjective recommendations would be ideally validated in a randomized, prospective trial.