Matrix Metalloproteinase-9 and Postoperative Outcomes in Carotid Endarterectomy: A Systematic Review.

Background/Objectives: Carotid endarterectomy (CEA) is the treatment of choice for severe symptomatic and asymptomatic carotid artery stenosis. Nonetheless, it carries risks and several complications, including stroke and death. Previous studies have indicated that elevated matrix metalloproteinase-9 (MMP-9) levels may serve as biomarkers for adverse outcomes after CEA. This systematic review investigates the association between plasma MMP-9 levels and adverse cardiovascular outcomes following CEA. Methods: PubMed/MedLine, Scopus and Web of Science were searched for studies assessing the relationship between plasma MMP-9 levels and postoperative outcomes after CEA. Assessment of studies' quality was performed using the National Heart, Lung, and Blood Institute (NHLBI) Study Quality Assessment Tool for observational cohorts and cross-sectional studies. Results: Five studies were included (n = 891 participants). All five were retrospective cohort studies. MMP-9 was significantly higher in patients who presented with a combination of amaurosis fugax, central retinal artery occlusion, TIA and minor/major stroke at follow-up. However, individual outcomes like TIA or stroke did not consistently correlate with MMP-9 levels. Additionally, increased MMP-9 levels were also associated with cognitive dysfunction post CEA. Conclusions: Despite the potential of MMP-9 levels to serve as a biomarker for predicting postoperative cerebrovascular complications, this review presents limitations, including a high risk of bias in included studies and variability in methodologies. There is a need for further research with larger cohorts to validate these findings and improve risk stratification and management strategies for patients undergoing CEA.