The SURTAVI trial demonstrated the noninferiority of transcatheter aortic valve implantation (TAVI) to surgical aortic valve replacement (SAVR) in patients with severe, symptomatic aortic stenosis at intermediate surgical risk. Most TAVI patients received an early generation device which is no longer commercially available. This analysis compares TAVI outcomes in patients that received the Evolut R valve to those of similar patients randomized to SAVR in the SURTAVI trial. The continued access study of SURTAVI (CAS) enrolled 290 patients. Of them, 252 were implanted with the 23, 26, or 29 mm Evolut R device. Propensity-score matching between this group and SURTAVI SAVR patients with annular diameter of 26 mm or less was based on 22 clinical characteristics, resulting in 197 matched pairs for analysis. The primary end point for comparison was the rate of all-cause mortality or disabling stroke at 1-year. The mean age for TAVI and SAVR patients in the propensity-score matched population was 79.1 years and STS-PROM was 4.0 ± 1.5% for TAVI and 3.9% ± 1.3% for SAVR. The rate of all-cause mortality or disabling stroke at 30-days significantly favored TAVI (0.5% vs 5.1%; p = 0.006). At 1-year TAVI was numerically favored (4.1% vs 8.2%; p = 0.082). In conclusion, compared with SAVR, TAVI using Evolut R had a favorable 30-day safety profile, significantly better hemodynamic performance, and a comparable 1-year rate of all-cause mortality or disabling stroke, suggesting this may be a preferred treatment for patients with severe, symptomatic aortic stenosis at intermediate surgical risk.
We report new imaging polarimetry observations of the Galactic compact HII region K3-50 using CanariCam at the Gran Telescopio Canarias. We use a standard polarimetric analysis technique, first outlined by Aitken, to decompose the observed polarisation images centred at 8.7, 10.3, and 12.5 $\mu$m into the emissive and absorptive components from silicate grains that are aligned with the local magnetic field. These components reveal the spatially-resolved magnetic field structures across the mid-infrared emission area of K3-50. We examine these structures and show that they are consistent with previously observed features and physical models of K3-50, such as the molecular torus and the ionised outflow. We propose a 3D geometry for all the structures seen at different wavelengths. We also compute relevant physical quantities in order to estimate the associated magnetic field strengths that would be implied under various physical assumptions. We compare these results with MHD simulations of protostar formation that predict the magnetic field strength and configuration. We find that the magnetic field may be dynamically important in the innermost 0.2 pc of the molecular torus, but that the torus is more likely to be rotationally-supported against gravity outside this radius. Similarly, magnetic fields are unlikely to dominate the {\em global} physics of the ionised outflow, but they may be important in helping confine the flow near the cavity wall in some locations. Ours is the first application of the Aitken technique to spatially-resolved magnetic field structures in multiple layers along the line of sight, effectively a method of "polarisation tomography."
Objectives This study sought to assess the vascular response of overlapping Absorb stents compared with overlapping newer-generation everolimus-eluting metallic platform stents (Xience V [XV]) in a porcine coronary artery model. Background The everolimus-eluting bioresorbable vascular scaffold (Absorb) is a novel approach to treating coronary lesions. A persistent inflammatory response, fibrin deposition, and delayed endothelialization have been reported with overlapping first-generation drug-eluting stents. Methods Forty-one overlapping Absorb and overlapping Xience V (XV) devices (3.0 × 12 mm) were implanted in the main coronary arteries of 17 nonatherosclerotic pigs with 10% overstretch. Implanted coronary arteries were evaluated by optical coherence tomography (OCT) at 28 days (Absorb n = 11, XV n = 7) and 90 days (Absorb n = 11, XV n = 8), with immediate histological evaluation following euthanasia at the same time points. One animal from each time point was evaluated with scanning electron microscopy alone. A total of 1,407 cross sections were analyzed by OCT and 148 cross sections analyzed histologically. Results At 28 days in the overlap, OCT analyses indicated 80.1% of Absorb struts and 99.4% of XV struts to be covered (p < 0.0001), corresponding to histological observations of struts with cellular coverage of 75.4% and 99.6%, respectively (p < 0.001). Uncovered struts were almost exclusively related to the presence of “stacked” Absorb struts, that is, with a direct overlay configuration. At 90 days, overlapping Absorb and overlapping XV struts demonstrated >99% strut coverage by OCT and histology, with no evidence of a significant inflammatory process, and comparable % volume obstructions. Conclusions In porcine coronary arteries implanted with overlapping Absorb or overlapping XV struts, strut coverage is delayed at 28 days in overlapping Absorb, dependent on the overlay configuration of the thicker Absorb struts. At 90 days, both overlapping Absorb and overlapping XV have comparable strut coverage. The implications of increased strut thickness may have important clinical and design considerations for bioresorbable platforms.
The current understanding of the pathophysiology of coronary artery disease relies on the potential adverse effect of myocardial ischemia (1). Even though the ischemia hypothesis has been placed at the core of the evaluation of patients with stable coronary artery disease, no clear evidence supports the benefit of revascularization in terms of hard clinical endpoints namely myocardial infarction and death (2).
Objective SYNTAX study compares outcomes of coronary artery bypass grafting with percutaneous coronary intervention in patients with 3-vessel and/or left main disease. Complexity of coronary artery disease was quantified by the SYNTAX score, which combines anatomic characteristics of each significant lesion. This study aims to clarify whether SYNTAX score affects the outcome of bypass grafting as defined by major adverse cerebrovascular and cardiac events (MACCE) and its components over a 2-year follow-up period. Methods Of the 3075 patients enrolled in SYNTAX, 1541 underwent coronary artery bypass grafting (897 randomized controlled trial patients, and 644 registry patients). All patients undergoing bypass grafting were stratified according to their SYNTAX score into 3 tertiles: low (0–22), intermediate (22–32), and high (≥33) complexity. Clinical outcomes up to 2 years after allocation were determined for each group and further risk factor analysis was performed. Results Registry patients had more complex disease than those in the randomized controlled trial (SYNTAX score: registry 37.8 ± 13.3 vs randomized 29.1 ± 11.4; P < .001). At 30 days, overall coronary bypass mortality was 0.9% (registry 0.6% vs randomized 1.2%). MACCE rate at 30 days was 4.4% (registry 3.4% vs randomized 5.2%). SYNTAX score did not significantly affect overall 2-year MACCE rate of 15.6% for low, 14.3% for medium, and 15.4% for high SYNTAX scores. Compared with randomized patients, registry patients had a lower rate of overall MACCE rate (registry 13.0% vs randomized 16.7%; P = .046) and repeat revascularization (4.7% vs 8.6%; P = .003), whereas other event rates were comparable. Risk factor analysis revealed left main disease (P = .049) and incomplete revascularization (P = .005) as predictive for adverse 2-year outcomes. Conclusions The outcome of coronary artery bypass grafting was excellent and independent from the SYNTAX score. Incomplete revascularization rather than degree of coronary complexity adversely affects late outcomes of coronary bypass.
Structural instabilities have generally been regarded as entities that are best avoided in practice. However, with the rapid emergence of nonlinear mathematics, computational power and manufacturing techniques, the exploitation of the geometrically nonlinear range is becoming increasingly feasible for a wider range of applications. Currently, a pilot study is presented concerning the design of sandwich structures and in particular the lattice core metamaterial. The internal structure of the lattice core is deliberately disrupted by auxetic inclusions to engineer potentially exploitable features for energy absorption or structural isolation applications. A pilot numerical study shows the effect that the inclusions have on the nonlinear mechanical response such that the post-buckling behaviour may be adjusted by design to create beneficial features.
