The Impact of Compliance with Imaging Follow-up on Mortality After Endovascular Abdominal Aortic Aneurysm Repair: A Population Based Cohort Study.

OBJECTIVE: Compliance with regular imaging follow-up after endovascular aortic aneurysm repair (EVAR) is inconsistent, and evidence of benefit from scheduled long-term surveillance is limited. This study sought to characterize the association between post-EVAR imaging frequency and long-term survival.

METHODS: Using administrative health databases for the province of Ontario, Canada, a cohort of patients was identified who underwent EVAR between 2004 and 2014. Minimum appropriate imaging follow-up (MAIFU) was defined as a CT scan or ultrasound of the abdomen within 90 days of EVAR as well as every 15 months thereafter. Multivariate time to event analyses characterized the association between compliance with MAIFU over time and all-cause mortality.

RESULTS: 4988 patients treated by EVAR were identified. Median follow-up was 3.4 years (IQR 2.0-5.3 years) and 90 day mortality was 1.6%. Among those who survived over 90 days, 87% (N = 4251 of 4902) underwent at least one CT scan or ultrasound of the abdomen within 90 days, but only 58% (N = 2859 of 4902) went on to meet MAIFU criteria. Infrequent imaging correlated with lower follow-up by a vascular surgeon, but not with infrequent primary care or specialist consultations. Consistently meeting MAIFU criteria was associated with a lower risk of death when compared with missing the first imaging follow-up within 90 days (HR 0.82, 95% CI 0.69-0.96, p = .014), or when compared with having first imaging follow-up within 90 days but subsequently not meeting MAIFU criteria (HR 0.78, 95% CI 0.68-0.91, p = .001). A larger proportion of the follow-up period meeting MAIFU criteria was associated with a lower risk of death.

CONCLUSIONS: These data support efforts to improve compliance with imaging surveillance after EVAR.