Background: Our objective was to investigate whether patients undergoing standard endovascular aneurysm repair (EVAR) outside the instructions for use (IFU) have worse outcomes than patients treated within IFU.
Methods: We conducted a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Electronic bibliographic sources were searched up to January 2019 using a combination of controlled vocabulary (thesaurus) and free-text terms to identify studies comparing outcomes of EVAR in patients treated outside versus within IFU. Pooled estimates of dichotomous outcomes were calculated using odds ratio (OR) or risk difference (RD) and 95% confidence interval (CI). We conducted a time-to-event data meta-analysis using the inverse-variance method and reported the results as summary hazard ratio (HR) and associated 95% CI. Random-effects methods of meta-analysis were applied. We formed meta-regression models to explore heterogeneity as a result of changes in practice over time.
Results: We identified 17 observational cohort studies published between 2011 and 2017, reporting a total of 4498 patients. The pooled prevalence of EVAR performed outside the IFU was 40% (95% CI, 33-48). Nonadherence to IFU was not associated with increased risk of perioperative mortality (RD, 0.01; 95% CI, -0.00 to 0.01; P = .23), aneurysm rupture (HR, 1.34; 95% CI, 0.30-5.93; P = .70), aneurysm-related mortality (HR, 0.88; 95% CI, 0.20-3.84; P = .86), technical failure (RD, 0.01; 95% CI, -0.03 to 0.05; P = .56), requirement for adjunctive procedures (OR, 1.48; 95% CI, 0.81-2.71; P = .20), type I endoleak (HR, 2.28; 95% CI, 0.58-8.91; P = .24), aneurysm sac expansion (HR, 0.86; 95% CI, 0.55-1.33; P = .49), or aneurysm-related reintervention (HR, 1.04; 95% CI, 0.81-1.34; P = .74). The overall mortality was significantly higher in patients treated outside the IFU (HR, 1.20; 95% CI, 1.02-1.42; P = .03). Meta-regression showed that the prevalence of EVAR performed outside the IFU has increased over time ( P = .019).
Conclusions: Standard EVAR outside the IFU was not found to have worse aneurysm-related outcomes than treatment within the IFU. Standard EVAR outside the IFU could be considered in selected patients who are deemed high risk for complex open or endovascular surgery.