1.
Arterial tortuosity in genetic arteriopathies.
Morris, SA
Current opinion in cardiology. 2015;(6):587-93
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Abstract
PURPOSE OF REVIEW Arterial tortuosity is emerging as a common feature in genetically mediated thoracic aortic disease that may be prognostic. This review will summarize recent literature on arterial tortuosity in the setting of genetic arteriopathies. RECENT FINDINGS Although arterial tortuosity has been primarily described in Loeys-Dietz syndrome due to TGFBR1 and TGFBR2 mutations and in arterial tortuosity syndrome due to SLC210A mutations, recent studies that use quantitative measures of tortuosity suggest that tortuosity is present in many other genetic conditions associated with aortic dilation and dissection. The mechanisms of the development of tortuosity in these disorders are not fully understood, but are founded in the concept that there is abnormal, pathologic arterial lengthening in a fixed space, resulting in more tortuous vessels. Further studies suggest that patients with increased arterial tortuosity are at increased risk of adverse cardiovascular events, including aortic surgery, aortic dissection, and death. SUMMARY Arterial tortuosity is commonly present in genetically mediated aortic disease. Given the suboptimal performance of aortic dimension alone in predicting aortic dissection, quantification of tortuosity may augment the current algorithms for determining risk in patients with aortic disease.
2.
Clinical experience with metal-on-metal total joint replacements: indications and results.
Learmonth, ID, Gheduzzi, S, Vail, TP
Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine. 2006;(2):229-37
Abstract
Survivorship of total joint arthroplasty depends on the durability of fixation and durability of articulation. The metal-on-polyethylene articular couple has been the most widely used. Polyethylene wear (and the associated cytochemical events that culminate in osteolysis) has been identified as a major factor adversely influencing the durability of joint replacement. This stimulated the orthopaedic community to explore the possibility of using alternative bearings with lower wear rates. Hard-on-hard bearings have been shown to be associated with reduced wear. Metal-on-metal bearings have wear rates that are 20-100 times lower than metal on conventional polyethylene. However, patients with metal-on-metal articulations have increased levels of cobalt and chromium in the serum and urine, and this has raised concerns about toxicity, mutagenesis, and hypersensitivity. At this stage there is no epidemiological evidence to suggest that the risk of carcinogenesis is anything more than theoretical. Successful long-term results have been reported with the cast cobalt-chromium metal-on-metal couples of the mid-1960s. Tissues retrieved at revision of these implants did not show the giant-cell inflammatory response associated with polyethylene particles. Several researchers have reported excellent mid-term results with the current generation of high-precision metal-on-metal bearings.