EVAR and OPEN treatment of abdominal aortic aneurysm: What is the role of MMP-9 in the follow-up?

INTRODUCTION: The aim of our study is to verify the role of metalloproteinases in endovascular repair (EVAR) and OPEN surgery treatment for abdominal aortic aneurysm (AAA). Postoperatively, these enzymes could represent an important biomarker to adapt diagnostic tests and further investigations during follow-up. MATERIAL AND METHOD: From 2004 to 2008, 55 patients were considered with AAA. Of these, 33 patients (mean age: 70.1 years), (mean AAA diameter: 5.4cm) were treated with OPEN surgery (group A) and 22 (mean age: 74.1 years) (mean AAA diameter: 5.1cm) were treated with EVAR. In 17 of them, there were no signs of endoleak (group B1), while in 5 patients, a presence of endoleak (group B2) was detected. Plasma samples were collected in order to determine MMP-9 activity. Enzyme immunoassay was performed preoperatively at 1, 3, 6 and 12 months. Patients treated conventionally were clinically examined after 1 and 12 months by ultrasound. Patients undergoing EVAR treatment were clinically examined by CT scan after 1, 3, 6 and 12 months. The analysis was done by assessing the interaction over time of the MMP-9 value in B1 and B2 groups. RESULTS: The average values observed for MMP-9 were preoperatively and at 1, 3, 6 and 12 months, respectively: in group A 150.8ng/mL (SD=30.5), 252.5ng/mL (SD=25.2), 315.4ng/mL (SD=22.7), 295.3ng/mL (SD=26.8), 210.7ng/mL (SD=30.2); in group B1 105ng/mL (SD=10.8), 125.6ng/mL (SD=18), 85.8ng/mL (SD=19.9), 95ng/mL (SD=20.2), 80.4ng/mL (SD=15.6); in group B2 149ng/mL (29.2), 375.4ng/mL (SD=40.2), 215ng/mL (SD=35.9), 180ng/mL (SD=20.2), 175ng/mL (SD=33.4). The MMP-9 level was higher in group B2 compared to group B1 (P=0.01), suggesting a correlation with the presence of the endoleak. CONCLUSIONS: This preliminary study shows that MMP-9 may be a biomarker of the presence of endoleak. Other further investigations and larger series are needed to show that metalloproteases could play a role in the follow-up of EVAR treated patients.