Matrix metalloproteinase 9 activity in patients before and after endovascular or surgical repair of abdominal aortic aneurysms

The objective of this prospective study was to assess matrix metalloproteinase 9 (MMP-9) activity in patients undergoing open surgery or endovascular repair of abdominal aortic aneurysms (AAAs), comparing changes in plasma levels in the two groups. We studied 12 patients after conventional open surgery and 9 patients after endovascular aneurysm repair. MMP-9 was assayed in plasma at baseline and 1 week and 1 month thereafter. Preoperative MMP-9 levels were similar in the two groups (41.7 ± 19.1 vs 44.4 ± 24.6 ng/mL; p = not significant). Assessment 1 week later showed that MMP levels in both repair groups had increased. In the open surgery group, they increased significantly (59.7 ± 16.8 ng/mL; p < .05) but not in the endovascular group (49.3 ± 32.4 ng/mL). One month later, MMP-9 levels decreased in both groups but not significantly (to 32.6 ± 24.6 ng/mL for open surgery repair and to 34.7 ± 23.5 ng/mL for endovascular repair). At 1 month after repair, MMP-9 levels decreased significantly only in smokers, whereas in nonsmokers, they did not (from 46.9 ± 22.1 to 31.7 ± 21.5 ng/mL in smokers [p < .05] vs from 34.7 ± 17.4 to 37.1 ± 28.9 ng/mL in nonsmokers). This study confirms that enzyme secretion changes during the postoperative course. The differing patterns of MMP-9 expression prevent us from reaching definitive conclusions about the use of MMP-9 as a marker during early postprocedural follow-up. An important matter to clarify is the role of MMP-9 in long-term follow-up, especially after endovascular AAA repairs.