Meta-analysis and meta-regression analysis of iliac limb occlusion after endovascular aneurysm repair

OBJECTIVE:Our objective was to investigate the incidence, interventions and outcomes of iliac limb occlusion after endovascular aneurysm repair (EVAR). METHODS:We performed a systematic review that conformed to the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines using a registered protocol (CRD42017064375). We considered studies reporting patients with iliac limb occlusion after EVAR. We interrogated electronic information sources and bibliographic reference lists using a combination of free text and controlled vocabulary searches. We conducted a proportion meta-analysis of outcomes applying a random effects model. We used mixed effects (methods of moments) regression models to investigate whether the incidence of iliac limb occlusion changed over time. RESULTS:We identified 13 studies reporting a total of 5454 patients who underwent EVAR from 1995 to 2014. The pooled incidence estimate of primary iliac limb occlusion was 5.6% (95% confidence interval [CI], 4.0-7.8). The incidence of iliac limb occlusion was more pronounced in old studies and declined in more recently published studies (slope P = .022; Q=5.279). Forty-four percent (95% CI, 36%-52%) had an acute presentation. One-half of the patients (48%; 95% CI, 41%-56%) presented within 30 days of EVAR. Seventeen percent (95% CI, 13%-23%) underwent endovascular treatment, 8% (95% CI, 5%-13%) received hybrid procedures, and 61% (95% CI, 54%-67%) had open surgery. The 30-day mortality was 0.036 (95% CI, 0.018-0.070; heterogeneity: P = .999, I2 = 0%). The rate of limb loss within 30 days and during follow-up was 0.031 (95% CI, 0.015-0.063; heterogeneity: P = .999; I2 = 0%) and 0.045 (95% CI, 0.024-0.083; heterogeneity: P = .978; I2 = 0%), respectively. Reintervention was undertaken in 0.080 (95% CI, 0.048-0.130; heterogeneity P = .919; I2 = 0%) over a follow-up ranging from 7 to 39 months. The mortality during follow-up was 0.056 (95% CI, 0.031-0.099; heterogeneity: P = .866; I2 = 0%). CONCLUSIONS:Iliac limb occlusion occurred in 5.6% of patients after EVAR. One-half of these patients presented early. Even though surgical treatment has been used more frequently, there is insufficient evidence to suggest its superiority over endovascular/hybrid repair. A considerable number of patients will require reintervention. Future research is needed in identifying patients at risk of iliac limb occlusion.