Cardiovascular disease is the leading cause of mortality in the United States. Peripheral artery disease (PAD) affects a substantial portion of the elderly population (>70 years). PAD can be symptomatic or asymptomatic, and treatment is directed towards improving functional vessel patency and limb salvage. Revascularization surgical treatments are needed in some cases, and it is not always possible to use autologous veins for vascular grafting. In this case, synthetic materials may be used. Synthetic materials such as expanded polytetrafluoroethylene (ePTFE) and poly (ethylene terephthalate) (Dacron) have been used. These materials are much stiffer compared to normal arterial vessels so developing alternative materials is an active area of research. One such potential material is a p olyvinyl alcohol cryogel reinforced arterial model (PRAM). In this study we used shear wave elastography (SWE) techniques to compare the mechanical behavior of excised aortas and anastomoses formed between the aortas and the Dacron, ePTFE, and PRAM materials. Different initial longitudinal strains (0%–40%) and transmural pressures (20–180 mmHg) were used to test a wide range of parameters that are within physiological ranges. We found that the PRAM materials had similar mechanical behavior in terms of group velocity measured in the vessel wall with respect to the excised aortas compared to the Dacron and ePTFE that had higher values of group velocity. The ratios of the group velocity for the PRAM material with respect to the aortas ranged from 0.83 to 1.13 where the Dacron and ePTFE had ranges of 1.12–2.22 and 1.91–3.10 for the same stretch and pressure ranges. The PRAM materials provide an alternative vascular material with better mechanical matching with excised aortas.
Chronic venous insufficiency (CVI) leads to skin changes with dermal hemosiderin deposition. We studied the presence of hemosiderin in the urine to assess if this could be used as a biochemical marker for CVI. Hereby we present a case control study conducted in a tertiary care centre in South India. There were 100 cases with evidence of advanced CVI (the Clinical-Etiology-Anatomy-Pathophysiology classification: C5, C6) confirmed by duplex scanning. Controls were 50 patients with leg ulcers due to other etiologies. All patients were subjected to urinary hemosiderin testing. In all 100 patients with CVI (C5 and C6 disease) axial venous reflux was confirmed by duplex ultrasound. Superficial venous reflux was noted in 71% of patients and deep venous reflux in 54.%. Primary venous insufficiency was the etiology in 81% of patients. Only 4/100 patients had detectable amounts of hemosiderin in the urine. Urine hemosiderin testing to determine presence or absence of CVI yielded the following values: positive predictive value-80%; negative predictive value-33%; sensitivity-4% and specificity-98%. The test could not be recommended as a marker of CVI. In Indian patients urinary hemosiderin is not a useful screening test in CVI.
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