Utility of conventional aortic root shot angiography for SAPIEN 3 prosthesis sizing in TAVI: feasibility and inter-reader variability.

Background: The gold-standard approach to prosthesis sizing before transcatheter aortic valve implantation (TAVI) is multislice computed tomography (MSCT). We aimed to investigate whether conventional aortic root angiography (CA) alone can reliably facilitate valve selection and to describe its inter-reader variability. Methods: Five TAVI specialists (3 interventional cardiologists and 2 cardiac surgeons) independently reviewed preprocedural CAs for 50 patients implanted with the Edwards SAPIEN 3 valve. Results: The prosthesis size selected based on visual CA appraisal matched that based on MSCT in 60% of cases (range: 50%-68%), with undersizing in 11% (4%-33%) and oversizing in 29% (10%-46%; p=0.187 for equality of the proportions test). Agreement between CA-based and MSCT-based valve selection was moderate (K=0.41; Kw=0.61). Reassessment of choice following awareness of the annulus long-axis diameter did not significantly improve this agreement (0.40 and 0.63, respectively), though more undersizing (14%) and less oversizing (25%) occurred. Correct valve selection was more common in interventional cardiologists than cardiac surgeons (66% vs 53%; p=0.0391), who made more oversizing errors. Conclusions: There is a modest agreement between CA-based and MSCT-based SAPIEN 3 selection. Although the former should not be performed routinely, it may be informative in settings where MSCT and transoesophageal echocardiography are unavailable.

Fully Reversible Quantitative Phase Transfer of Gold Nanoparticles Using Bifunctional PNIPAM Ligands.

Ligand exchange with end-functionalized polymers is often applied to render nanoparticles with enhanced colloidal stability, to change the solubility in various environments, and/or to introduce new functionalities. Here we show that exchange of citrate molecules with α-trithiocarbonate-ω-carboxyl-terminated poly(N-isopropylacrylamide) can successfully stabilize spherical gold particles of different diameters ranging from 15 to 53 nm. This is verified by transmission electron microscopy, dynamic light scattering, and extinction spectroscopy. We show that the polymer-decorated nanoparticles respond to temperature and pH allowing access to control interparticle interactions. In a range of pH slightly below the pKa of the terminal carboxyl groups, phase transfer of the particles from water to chloroform can be mediated by increasing the dispersion temperature above the lower critical solution temperature of poly(N-isopropylacrylamide). Upon cooling, fully reversible phase transfer to the water phase is observed. Extinction spectroscopy reveals phase transfer efficiencies close to 100% for every system under investigation.

Influence of Temperature on the Colloidal Stability of Polymer-Coated Gold Nanoparticles in Cell Culture Media.

The temperature-dependence of the hydrodynamic diameter and colloidal stability of gold-polymer core-shell particles with temperature-sensitive (poly(N-isopropylacrylamide)) and temperature-insensitive shells (polyallylaminine hydrochloride/polystyrensulfonate, poly(isobutylene-alt-maleic anhydride)-graft-dodecyl) are investigated in various aqueous media. The data demonstrate that for all nanoparticle agglomeration, i.e., increase in effective nanoparticle size, the presence of salts or proteins in the dispersion media has to be taken into account. Poly(N-isopropylacrylamide) coated nanoparticles show a reversible temperature-dependent increase in size above the volume phase transition of the polymer shell when they are dispersed in phosphate buffered saline or in media containing protein. In contrast, the nanoparticles coated with temperature-insensitive polymers show a time-dependent increase in size in phosphate buffered saline or in medium containing protein. This is due to time-dependent agglomeration, which is particularly strong in phosphate buffered saline, and induces a time-dependent, irreversible increase in the hydrodynamic diameter of the nanoparticles. This demonstrates that one has to distinguish between temperature- and time-induced agglomerations. Since the size of nanoparticles regulates their uptake by cells, temperature-dependent uptake of thermosensitive and non-thermosensitive nanoparticles by cells lines is compared. No temperature-specific difference between both types of nanoparticles could be observed.

Complications in the clinical course of tako-tsubo cardiomyopathy.

OBJECTIVE: This study evaluated the frequency, severity and outcome of complications in the clinical course of tako-tsubo cardiomyopathy (TTC). BACKGROUND: TTC is regarded as a benign disease since left ventricular (LV) function returns to normal within a short time. However, severe complications have been reported in selected patients. METHODS: From 37 hospitals, 209 patients (189 female, age 69 ± 12 years) were prospectively included in a TTC registry. RESULTS: Complications developed in 108/209 patients (52%); 23 (11%) had >2 complications. Complications occurred median 1 day after symptom onset, and 77% were seen within 3 days. Arrhythmias were documented in 45/209 patients (22%) including atrial fibrillation in 32 (15%) and ventricular tachycardia in 17 (8%). Of 8 patients resuscitated (4%), 6 survived. Additional complications were right ventricular involvement (24%), pulmonary edema (13%), cardiogenic shock (7%), transient intraventricular pressure gradients (5%), LV thrombi (3%) and stroke (1%). During hospitalization, 5/209 patients (2.5%) died. Patients with complications were older (70 ± 13 vs 67 ± 10 years, p=0.012), had a higher heart rate (91 ± 26 vs 83 ± 19/min, p=0.025), more frequently Q\ waves on the admission ECG (36% vs 21%, p=0.019) and a lower LV ejection fraction (47 ± 15 vs 54 ± 14%, p = 0.002). Multivariate regression analysis identified Q-waves on admission (OR 2.49, 95% CI 1.23-5.05, p=0.021) and ejection fraction ≤ 30% (OR 4.03, 95% CI 1.04-15.67, p=0.022) as independent predictors for complications. CONCLUSIONS: TTC may be associated with severe complications in half of the patients. Since the majority of complications occur up to day 3, monitoring is advisable for this time period.