The association between plasma matrix metalloproteinase-9 concentration and endoleak after endovascular aortic aneurysm repair: a meta-analysis.

BACKGROUND The most common complication after endovascular aneurysm repair (EVAR) is continued perfusion of the aneurysmal sac, known as endoleak. Assessment of markers released from the aneurysm wall into the circulation has been suggested as a possible alternative for detecting endoleaks. The aim of this meta-analysis was to examine if circulating concentrations of matrix metalloproteinase (MMP)-9 were higher in patients with endoleak after EVAR. METHODS A systematic search of the MEDLINE, EMBASE, Scopus, Web of Science and Cochrane Library Databases was conducted. Studies reporting circulating MMP-9 concentrations in patients who did and did not have endoleaks after EVAR that met inclusion and exclusion criteria were included. A meta-analysis using a random effects model was performed to assess the association between circulating concentrations of MMP-9 and endoleak. Sensitivity analyses were performed using the one-study remove approach. Study quality was assessed using a quality assessment tool. RESULTS Prior to EVAR, plasma concentrations of MMP-9 were similar in patients that did and did not subsequently develop an endoleak (Standardised mean difference: -0.13; 95% confidence interval, -0.63 to 0.37, p=0.60). 1 month after EVAR, plasma concentrations of MMP-9 were non-significantly higher in patients that had an endoleak (Standardized mean difference: 0.56; 95% CI -0.02 to 1.15, p=0.06). 3 months after EVAR, plasma concentrations of MMP-9 were higher in patients that had an endoleak (Standardised mean difference: 1.42; 95% confidence interval, 0.48-2.36, p<0.003). CONCLUSIONS This meta-analysis suggests that plasma MMP-9 concentrations measured 3 months after EVAR are higher in patients that have an endoleak. It remains to be established whether plasma MMP-9 testing is sufficiently accurate for use as a surveillance test for endoleak after EVAR.