Outcomes of Carotid Revascularization in the Treatment of Restenosis After Prior Carotid Endarterectomy

Abstract

Study design: A systematic review and meta-analysis of Mendelian randomization studies using Medline, Cumulative Index to Nursing and Allied Health Literature Complete, and Scopus databases.Key findings: Sixteen studies involving 34,050 patients with an abdominal aortic aneurysm (AAA) and 2,205,894 controls were included. Metaanalyses suggested that a 1 standard deviation increase in high-density lipoprotein cholesterol (HDL-C) significantly decreased, and a 1 standard deviation increase in low-density lipoprotein cholesterol (LDL-C) significantly increased, the risk of AAA. A 1 standard deviation increase in triglycerides did not significantly increase the risk of AAA.Conclusion: This meta-analysis suggested that LDL-C and HDL-C are positive and negative casual risk factors for AAA.Commentary: What factors may predispose to AAA formation and growth and what factors may be protective? Mendelian randomization may overcome biases of observational studies and may replicate results of large randomized controlled trials. The main findings of this metaanalysis were that high LDL-C and low HDL-C levels were risk factors for increased risk of AAA. Lowering LDL-C levels may decrease the risk of developing AAA, although it is unclear if this strategy slows AAA growth. Other factors have been shown to be associated with AAA development including inflammatory markers (IL-1Ra, IL-6R, sIL-6R), high diastolic blood pressure, and smoking. But diabetes is associated with a lower risk of AAA, which has been attributed to high blood glucose promoting extracellular matrix glycation and modulation of aortic wall matrix remodeling and inflammation. Thirteen previous randomized controlled trials have reported that drugs including antibiotics, beta-blockers, angiotensin-converting enzyme inhibitors, and mast cell inhibitors do not slow AAA growth.Remember when your mother told you to eat your oatmeal every morning? (Oatmeal has soluble fiber, which decreases LDL-C levels). She knew what she was talking about.