OPEN AND EVAR TREATMENT FOR ABDOMINAL AORTIC ANEURYSM: IS THERE A ROLE FOR MMP-9 IN THE FOLLOW-UP?

INTRODUCTION The aim of our study was to verify the role of metalloproteinases before and after EVAR and OPEN treatment for AAA. Postoperatively these enzymes could represent an important marker to determine which patients can limit the amount of diagnostic tests and further investigations which are necessary during follow-up. MATERIAL AND METHOD From Nov 2004 to July 2008 were considered 55 patients with AAA. Of these, 33 patients (average age 70.6), (AAA average diameter: 5.4 cm) were treated OPEN (group A) and 22 (average age 70.1) (mean AAA diameter: 5.5 cm) were treated EVAR. After placement of the endoprothesis, in 5 was detected the presence of endoleak (group B1), while in 17 there were no signs of endoleak (group B2). In all cases samples were collected for determination of MMP-9. All assays were performed by enzyme immunoassay, preoperatively and at 1, 3, 6 and 12 months. Patients treated conventionally have been checked after 1 and 12 months by clinical examination and ultrasound. Patients undergoing EVAR treatment were monitored by clinical examination and CT scan after 1, 3, 6, and thereafter annually. RESULTS The average values observed for MMP-9 were, respectively: in group A 150.8 ng/ml, 264.5 ng/ml, 315.4 ng/ml, 295 ng/ml, 210 ng/ml; in group B1 144.1 ng/ml, 374.4 ng/ml, 215 ng/ml, 195 ng/ml, 180.4 ng/ml; in B2 107.1 ng / ml, 116.6 ng / ml, 80.6 ng / ml, 90.4 ng / ml, 85.6 ng / ml. The difference between the group B1 and group B2. (P = NS). DISCUSSION The metalloproteinase MMP-9 play a major role in the genesis and evolution of the aneurysm. In OPEN treated patients increased initial values can be related to the activation of biochemical mediators induced by the surgery. In EVAR patients, which has been demonstrated the presence of endoleak, the levels of MMP-9 may be related to the endoleak. CONCLUSIONS This preliminary study shows that MMP-9 may be a marker of the presence of endoleak. Other biochemical factors are involved and further investigations are needed to show that metalloproteases could play a role in the follow up of patients treated with EVAR.