Poly (vinyl alcohol) (PVA) hydrogels are highly attractive for biomedical applications, especially for controlled release of drugs and proteins. Recently, degradable PVA hydrogels have been described, having the advantage that the material disappears over time from the implantation site. Herein, we report the synthesis of radiopaque degradable PVA, which gives a further advantage that the position of the hydrogel can precisely be determined by X-ray fluoroscopy. Radiopacity has been introduced by replacing 0.5% of the pendent alcohol groups on the PVA with 4-iodobenzoylchloride. This level of substitution rendered the polymer adequately radiopaque. The subsequent modification of 0.8% of the pendent hydroxyl groups with an ester acrylate functional group allowed for cross-linking of the macromers. The radiopaque hydrogels degraded over a time span of 140 days. Rheology data suggested that the macromer solutions were appropriate for injection.
Quantification of aortic regurgitation by measurement of time-density changes on contrast aortography may improve the reproducibility of AR assessment in the catheter laboratory. Steps for standardised aortography acquisition are proposed.
Vertebroplasty and balloon kyphoplasty are widely used for the augmentation of osteoporosis-induced vertebral compression fractures. Almost invariably, an injectable poly(methyl methacrylate) (PMMA) bone cement that contains a large amount of BaSO(4) particles is used in these procedures. The deleterious effects of this radiopacifier on various properties of PMMA cement have been detailed in the literature. The objective of the present study was therefore to avoid such high levels of inorganic contrast agent and thus to develop an all-polymeric bone cement, for which radiopacity was provided by 60 wt % of an iodine-containing methacrylic copolymer, incorporated into the powder (IO cement), ultimately leading to 6.6 wt % of iodine in the cement. A large array of properties of this cement were determined, ranging from setting time and injectability to fatigue life under fully-reversed tension-compression loading and cytotoxicity, and a comprehensive comparison with a cement containing 30 wt % BaSO(4) in the powder component (BA cement) has been made (11 wt % of Ba in the cement). Statistical analyses of the results showed that, for the majority of the properties, the difference between the means for the two cements was not significant. It is therefore suggested that the IO cement is a suitable alternative to the BA cement for use in the aforementioned procedures.
AR after TAVI could be quantitated utilising LVOT-AR. The cut-point of >0.17 indicates a significant AR pertaining to increased intermediate-term mortality, especially in those with no significant pre-existing AR.
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