Synthesis and characterization of radiopaque iodine-containing degradable PVA hydrogels.

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.

The interaction of de novo and pre-existing aortic regurgitation after TAVI: insights from a new quantitative aortographic technique.

AIMS: The aim of this study was to evaluate the intermediate-term clinical impact of aortic regurgitation (AR) after transcatheter aortic valve implantation (TAVI) using a novel quantitative angiographic method taking into account the influence of pre-existing AR. METHODS AND RESULTS: AR after TAVI was quantified in 338 patients (age 82 [78-86] years; 55% male) and the influence on intermediate-term all-cause mortality was evaluated. In 228 aortograms, AR was quantitated using a dedicated videodensitometric method focused in the left ventricular outflow tract (LVOT-AR). Patients with LVOT-AR >0.17 had a significantly increased all-cause mortality at three years, compared with patients who had LVOT-AR ≤0.17 (adjusted hazard ratio [HR]: 1.73, 95% confidence interval [CI]: 1.05-2.86, p=0.032). Taking the influence of pre-existing AR into account, patients with post-procedural LVOT-AR >0.17 and ≤mild pre-existing AR had a significantly increased mortality at two years, compared to patients with LVOT-AR >0.17 and >mild pre-existing AR (HR: 2.55, 95% CI: 1.16-5.58, p=0.029). In those with >mild pre-existing AR (n=70), post-TAVI LVOT-AR >0.17 was not associated with increased mortality (HR: 0.77, 95% CI: 0.31-1.91, p=0.578). CONCLUSIONS: 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.

Clinical validation of a novel software for quantitative analysis of coronary intravascular ultrasound.

PURPOSE: CAAS IntraVascular (CAAS-IV) is a recently released software that provides options for sophisticated quantitative coronary ultrasound (QCU) analysis. The aim of this study was to validate CAAS-IV for QCU in diseased human coronaries. METHODS: Ten preprocedural and 5 postprocedural IVUS studies were derived from daily practice. Intraobserver, interobserver, intersoftware (CAAS-IV vs. Curad) and interplatform (CAAS-IV vs. Volcano console) variability were assessed for cross-sectional area (CSA) measurements. Interobserver and intersoftware comparisons were made for volume measurements. RESULTS: Measurements of lumen, EEM, plaque and stent CSA demonstrated small differences in the intraobserver (0.0±3.7%, -0.7±2.8%, -0.5±7.0% and -0.9±3.4%), interobserver (0.1±4.4%, 0.1±3.4%, -0.5±8.2% and -0.8±4.3%), intersoftware (-0.3±4.5%, 0.2±2.4%, 0.4±6.8% and -0.5±3.2%) and interplatform (0.7±7.9%, 0.9±4.0%, -1.1±12%, -1.8±3.6%) comparisons. For lumen, EEM, plaque and stent volume, the interobserver (-2.1±9.3%, 0.9±5.6%, 3.4±7.2% and -0.2±3.6%) and intersoftware (-2.2±6.2%, -2.6±6.1%, -2.7±12% and -4.1±3.2%) differences were substantially larger. Excluding large side-branches and calcifications, post-hoc measurements of lumen, EEM, plaque and stent volume showed small differences in the interobserver (-0.3±3.2%, 0.9±2.4%, 2.9±4.4% and -1.3±1.8%) and intersoftware (0.5±2.5%, -1.2±1.7%, -3.4±5.1% and -1.5±2.2%) comparisons. Analysis time for entire pullbacks was reduced by 19.2 [14.9-30.0]% using CAAS-IV (p<0.01). CONCLUSIONS: CAAS-IV demonstrated reliable QCU with excellent agreement with previously validated software and the IVUS imaging console. Precision and reproducibility of measurements were high, proving CAAS-IV to be a valid option for QCU analysis in clinical practice and research. Interactive contour editing reduced analysis time by 20%.

An objective and reproducible method for quantification of aortic regurgitation after TAVI.

AIMS: We describe a new semi-automated method that measures aortic regurgitation (AR) on contrast aortography with the objectives of reducing the inter-observer variability and standardising image acquisition. METHODS AND RESULTS: Aortograms from three participating centres were reviewed to generate the following quality criteria: entire left ventricle and aortic root in view, descending aorta or TOE probe not over-projected, breath hold, no table motion, and adequate contrast opacification of the aortic root. AR was visually graded (Sellers) and was quantified by measuring the area under time-contrast density curves in the aortic root (reference) and the left ventricle. Quality criteria were met in 44 retrospectively identified aortograms and in 22 (69%) of 32 prospectively collected aortograms. The visual AR grade (Sellers) was highly correlated with time-density measurements including relative area under the curve (RAUC) and qRA index (r=0.81 and 0.83, respectively, p<0.001). Inter-observer reproducibility of visual grading was moderate (kappa 0.47-0.60, p<0.001). Inter-observer measurement of RAUC and qRA index were highly correlated (r=0.98, p<0.001) and showed a high level of agreement. CONCLUSIONS: 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.