Management of left subclavian artery in type B aortic dissection treated with thoracic endovascular aorta repair.

OBJECTIVE: Thoracic endovascular aortic repair (TEVAR) has been the favored approach for the treatment of type B aortic dissection (TBAD). To obtain an adequate proximal landing zone, coverage of the left subclavian artery (LSA) will often be necessary. The occurrence of possible neurologic complications has continued to be debated. We investigated the management of the LSA in patients with TBAD undergoing endovascular repair. METHODS: We searched the PubMed and MEDLINE databases to October 2020 for studies of TEVAR for TBAD. Data on the study design, demographics, endograft details, LSA coverage and revascularization, mortality, complications, and follow-up were extracted and analyzed. The effects of LSA coverage and revascularization on neurologic complications and outcomes were investigated. RESULTS: A total of 26 reports (24 retrospective and 2 prospective) were deemed eligible for our study. A total of 1483 patients (mean age, 56.9 ± 6.2 years) had undergone TEVAR for acute (n = 932; 62.9%), subacute (n = 36; 2.4%), or chronic (n = 515; 34.7%) TBAD, with a success rate of 97.8% and hospital mortality of 4.9%. The LSA origin had been covered for 707 patients (47.7%), and 326 had undergone LSA revascularization (surgical, n = 96; endovascular, n = 170; unspecified or not reported, n = 60). LSA revascularization was concomitant for 68.1% of cases, after TEVAR for 1.8%, and not reported for 30.1%. Of 1146 patients, 10 (0.9%) had experienced left arm claudication, and the overall stroke rate was 3.3% (2.7% for the LSA group and 1% for the uncovered LSA group; P = .0815). Of the patients with stroke and a covered LSA, 1% (2 of 203) had undergone LSA revascularization and 4.8% (5 of 105) had not (P = .0478). Twenty-six patients (1.9%) had developed paraplegia: 0.7% (3 of 433) with a covered LSA, 1.4% (7 of 491) with an uncovered LSA (P = .3508), and not reported for 16 patients. Endoleak was present in 138 patients (13.4%) at a mean follow-up of 32.1 ± 25.6 months. CONCLUSIONS: Our review has shown that LSA coverage during endovascular repair for complicated TBAD will does not significantly increase the risk of neurologic complications; however, revascularization of the LSA should be always recommended.

Size matters: Influence of center size on quality of diabetes control in children and adolescents with type 1 diabetes-A longitudinal analysis of the DPV cohort.

BACKGROUND: Treatment of patients with type 1 diabetes requires experience and a specific infrastructure. Therefore, center size might influence outcome in diabetes treatment. OBJECTIVE: To analyze the influence of center size on the quality of diabetes treatment in children and adolescents in Germany and Austria. PATIENTS AND METHODS: In 2009 and 2018, we analyzed metabolic control, acute complications, and rates of recommended screening tests in the DPV cohort. Diabetes centers were classified according to the number of patients from "XS" to "XL" (<20 [XS], ≥20 to <50 [S], ≥50 to <100 [M], ≥100 to <200 [L], ≥200 [XL]). RESULTS: Over the 10-year period, metabolic control improved significantly in "M", "L" and "XL" diabetes centers. Treatment targets are best achieved in "M" centers, while "XS" centers have the highest mean hemoglobin A1c. The relation between hemoglobin A1c and center size follows a "v-shaped" curve. In 2009, conventional insulin therapy was most frequently used in "XS" centers, but in 2018, there was no difference in mode of insulin therapy according to center size. Use of CSII and sensor augmented CSII/hybrid closed loop increased with center size. Patients cared for in "XS" diabetes centers had the fewest follow-up visits per year. The rates of severe hypoglycemia and DKA were lowest in "XL" diabetes centers, and the rate of DKA was highest in "XS" centers. CONCLUSION: Center size influences quality of care in pediatric patients with type 1 diabetes. Further investigations regarding contributing factors such as staffing and financial resources are required.

de Gennes Narrowing and Relationship between Structure and Dynamics in Self-Organized Ion-Beam Nanopatterning.

Investigating the relationship between structure and dynamical processes is a central goal in condensed matter physics. Perhaps the most noted relationship between the two is the phenomenon of de Gennes narrowing, in which relaxation times in liquids are proportional to the scattering structure factor. Here, a similar relationship is discovered during the self-organized ion-beam nanopatterning of silicon using coherent x-ray scattering. However, in contrast to the exponential relaxation of fluctuations in classic de Gennes narrowing, the dynamic surface exhibits a wide range of behaviors as a function of the length scale, with a compressed exponential relaxation at lengths corresponding to the dominant structural motif-self-organized nanoscale ripples. These behaviors are reproduced in simulations of a nonlinear model describing the surface evolution. We suggest that the compressed exponential behavior observed here is due to the morphological persistence of the self-organized surface ripple patterns which form and evolve during ion-beam nanopatterning.

Effect of blood viscosity on the performance of virtually wall-less venous cannulas.

AIM: This study was designed to quantify the influence of blood as test medium compared to water in cannula bench performance assessment. METHODS: An in vitro circuit was set-up with silicone tubing between two reservoirs. The test medium was pumped from the lower reservoir by centrifugal pump to the upper reservoir. The test-cannula was inserted in a silicone tube connected between the lower reservoir and the centrifugal pump. Flow rate and pump inlet-pressure were measured for wall-less versus thin-wall cannula using a centrifugal pump in a dynamic bench-test for an afterload of 40-60 mmHg using two media: blood 10 g/dL and 5.6 g/dL and water 0 g/dL. RESULTS: The wall-less cannula showed significantly higher flows rates as compared to the thin-wall cannula (control), with both hemoglobin concentrations and water. Indeed, for a target volume of 200-250 mL of blood (Hg 10 g/dL) in the upper reservoir, the cannula outlet pressure (P) was -14 ± 14 mmHg versus -18 ± 11 mmHg for the wall-less and control respectively; the cannula outlet flow rate (Q) was 3.91 ± 0.41 versus 3.67 ± 0.45 L/min, respectively. At the same target volume but with a Hg of 5.7 g/dL, P was -16 ± 12 mmHg versus -19 ± 12 mmHg and Q was 4 ± 0.1 versus 4 ± 0.4 L/min for the wall-less cannula and control respectively. Likewise, P and Q values with water were -1 mmHg versus -0.67 ± 0.58 mmHg and 4.17 ± 0.45 L/min versus 4.08 ± 0.47 L/min for the wall-less and control respectively. CONCLUSION: Walls-less cannula showed 5.6% less pump inlet-pressure differences calculated between blood and water, as compared to that of thin-wall cannula (-21 times). Flow differences were 6% and 10% for the walls-less and thin-wall cannula respectively. We conclude that testing the cannula performance with water is a good scenario and can overestimate the flow by a 10%. However, superiority for wall-less is preserved with both water and blood.

Simulations of Co-GISAXS during kinetic roughening of growth surfaces.

The recent development of surface growth studies using X-ray photon correlation spectroscopy in a grazing-incidence small-angle X-ray scattering (Co-GISAXS) geometry enables the investigation of dynamical processes during kinetic roughening in greater detail than was previously possible. In order to investigate the Co-GISAXS behavior expected from existing growth models, calculations and (2+1)-dimension simulations of linear Kuramoto-Sivashinsky and non-linear Kardar-Parisi-Zhang surface growth equations are presented which analyze the temporal correlation functions of the height-height structure factor. Calculations of the GISAXS intensity auto-correlation functions are also performed within the Born/distorted-wave Born approximation for comparison with the scaling behavior of the height-height structure factor and its correlation functions.

Coherent X-ray Spectroscopy Elucidates Nanoscale Dynamics of Plasma-Enhanced Thin-Film Growth.

Sophisticated thin film growth techniques increasingly rely on the addition of a plasma component to open or widen a processing window, particularly at low temperatures. Taking advantage of continued increases in accelerator-based X-ray source brilliance, this real-time study uses X-ray Photon Correlation Spectroscopy (XPCS) to elucidate the nanoscale surface dynamics during Plasma-Enhanced Atomic Layer Deposition (PE-ALD) of an epitaxial indium nitride film. Ultrathin films are synthesized from repeated cycles of alternating self-limited surface reactions induced by temporally separated pulses of the material precursor and plasma reactant, allowing the influence of each on the evolving morphology to be examined. During the heteroepitaxial 3D growth examined here, sudden changes in the surface structure during initial film growth, consistent with numerous overlapping stress-relief events, are observed. When the film becomes continuous, the nanoscale surface morphology abruptly becomes long-lived with a correlation time spanning the period of the experiment. Throughout the growth experiment, there is a consistent repeating pattern of correlations associated with the cyclic growth process, which is modeled as transitions between different surface states. The plasma exposure does not simply freeze in a structure that is then built upon in subsequent cycles, but rather, there is considerable surface evolution during all phases of the growth cycle.

Atomic layer deposition of TiO2 on surface modified nanoporous low-k films.

This paper explores the effects of different plasma treatments on low dielectric constant (low-k) materials and the consequences for the growth behavior of atomic layer deposition (ALD) on these modified substrates. An O2 and a He/H2 plasma treatment were performed on SiCOH low-k films to modify their chemical surface groups. Transmission FTIR and water contact angle (WCA) analysis showed that the O2 plasma changed the hydrophobic surface completely into a hydrophilic surface, while the He/H2 plasma changed it only partially. In a next step, in situ X-ray fluorescence (XRF), ellipsometric porosimetry (EP), and Rutherford backscattering spectroscopy (RBS) were used to characterize ALD growth of TiO2 on these substrates. The initial growth of TiO2 was found to be inhibited in the original low-k film containing only Si-CH3 surface groups, while immediate growth was observed in the hydrophilic O2 plasma treated film. The latter film was uniformly filled with TiO2 after 8 ALD cycles, while pore filling was delayed to 17 ALD cycles in the hydrophobic film. For the He/H2 plasma treated film, containing both Si-OH and Si-CH3 groups, the in situ XRF data showed that TiO2 could no longer be deposited in the He/H2 plasma treated film after 8 ALD cycles, while EP measurements revealed a remaining porosity. This can be explained by the faster deposition of TiO2 in the hydrophilic top part of the film than in the hydrophobic bulk which leaves the bulk porous, as confirmed by RBS depth profiling. The outcome of this research is not only of interest for the development of advanced interconnects in ULSI technology, but also demonstrates that ALD combined with RBS analysis is a handy approach to analyze the modifications induced by a plasma treatment on a nanoporous thin film.

Acute Abdominal Pain as a Result of an Isolated Left Ovarian Vein Thrombosis.

Ovarian vein thrombosis (OVT) is a rare thromboembolic condition. It involves the right ovarian vein in 70-80% of cases. The risk factors for the development of OVT are pregnancy or puerperium, hormone therapy with estrogen, recent surgery or hospitalization, malignancy, pelvic inflammatory diseases, thrombophilia and idiopathic OVT. We present a rare case of left OVT in a young, non-pregnant woman in her 30 s. A high degree of suspicion is necessitated in patients with the triad of young-middle-aged female, pain abdomen in lower quadrant and hematuria to diagnose OVT. Contrast enhanced computer tomography (CT-venography) is the diagnostic modality of choice. The patient was initially treated with low molecular weight heparin and then switched to direct oral anticoagulants. At 6-monthsfollow-up the patient was free from any symptoms.

X-ray photon correlation spectroscopy in systems without long-range order: existence of an intermediate-field regime.

Successful X-ray photon correlation spectroscopy studies often require that signals be optimized while minimizing power density in the sample to decrease radiation damage and, at free-electron laser sources, thermal impact. This suggests exploration of scattering outside the Fraunhofer far-field diffraction limit d(2)/λ << R, where d is the incident beam size, λ is the photon wavelength and R is the sample-to-detector distance. Here it is shown that, in an intermediate regime d(2)/λ > R >> dξ/λ, where ξ is the structural correlation length in the material, the ensemble averages of the scattered intensity and of the structure factor are equal. Similarly, in the regime d(2)/λ > R >> dξ(τ)/λ, where ξ(τ) is a time-dependent dynamics length scale of interest, the ensemble-averaged correlation functions g(1)(τ) and g(2)(τ) of the scattered electric field are also equal to their values in the far-field limit. This broadens the parameter space for X-ray photon correlation spectroscopy experiments, but detectors with smaller pixel size and variable focusing are required to more fully exploit the potential for such studies.

Recovery of paraplegia after type B dissection due to spinal collateral recruitment.

Acute paraplegia could be a symptom of aortic dissection due to sudden compromise of arterial spinal cord blood supply. Complete spontaneous neurologic recovery is possible and was observed in the present case 3 hours after symptom onset. Spontaneous spinal cord reperfusion after acute type B dissection was probably due to two main mechanisms. Reperfusion of false lumen and collateral vascular network recruitment, recently confirmed by anatomic animal studies, serve as potential explanations. Favorable evolution of acute paraplegia after aortic dissection exists, but prognosis is uncertain, probably due to individual variable anatomic distribution of spinal cord blood supply.

Evidence for Family-Meakin dynamical scaling in island growth and coalescence during vapor phase deposition.

Using real-time grazing-incidence small-angle x-ray scattering, we find that the processes of island formation and coalescence during the room-temperature vapor phase deposition of aluminum lead to dynamical scaling of the evolving surface morphology. The scaling is quantitatively consistent with the self-similarity predicted by the Family-Meakin model, which was developed to describe liquid droplet deposition, growth, and coalescence. The Family-Meakin model assumes only that atomic diffusion over the substrate between islands or droplets is negligible and that diffusion between impinging islands or droplets is sufficient to give complete coalescence. Therefore the dynamical scaling morphology evolution identified here may be common in the initial stages of those solid film growth processes which proceed by island formation and growth.

Reduction aortoplasty: safe and durable treatment for borderline dilatation in selected patients.

BACKGROUND AND AIM OF THE STUDY: In aortic valve surgery, the management of ascending aortic dilatation is not clearly defined. Guidelines recommend replacement at diameters of 50 mm, but the handling of borderline dilatation has not been detailed. Reduction aortoplasty has been proposed as a less invasive and safe option in the case of a smaller dilatation above the sinotubular junction. METHODS: Between 1999 and 2009, reduction aortoplasties with or without external reinforcement associated with aortic valve surgery were performed in 82 patients. The ascending aortic diameter was measured echocardiographically at a mean follow up (FU) of 32 months (FU was 91% complete). RESULTS: The in-hospital mortality was 1.2%, and all patients were in NYHA class I or II. Echocardiography revealed a re-dilatation (> or = 5 mm) rate of 5.5%. One patient required reoperation. At univariate analysis, a preoperative dilatation >45 mm, persistent postoperative diameters >35 mm after reduction, and a younger age at the time of surgery (<65 years) were significant risk factors. Multivariate analysis confirmed the parameters for re-dilatation, and the area under the receiver operating curve was 0.85 for these three criteria. Mesh implantation, FU duration and bicuspid valve had no significant impact on outcome. CONCLUSION: Reduction aortoplasty is a less-invasive option to handle borderline supra-coronary aneurysms in the case of concomitant valve surgery, compared to aortic replacement. The mortality remained low, and equal to that for simple aortic valve replacement. A large preoperative aortic diameter and age < or = 65 years favored re-dilatation. Correct downsizing was technically demanding, but indispensable for long-term stabilization. Regard for these criteria could lead to numerous patients benefiting from this operative strategy, with good results.

Tailoring nanoporous materials by atomic layer deposition.

Atomic layer deposition (ALD) is a cyclic process which relies on sequential self-terminating reactions between gas phase precursor molecules and a solid surface. The self-limiting nature of the chemical reactions ensures precise film thickness control and excellent step coverage, even on 3D structures with large aspect ratios. At present, ALD is mainly used in the microelectronics industry, e.g. for growing gate oxides. The excellent conformality that can be achieved with ALD also renders it a promising candidate for coating porous structures, e.g. for functionalization of large surface area substrates for catalysis, fuel cells, batteries, supercapacitors, filtration devices, sensors, membranes etc. This tutorial review focuses on the application of ALD for catalyst design. Examples are discussed where ALD of TiO(2) is used for tailoring the interior surface of nanoporous films with pore sizes of 4-6 nm, resulting in photocatalytic activity. In still narrower pores, the ability to deposit chemical elements can be exploited to generate catalytic sites. In zeolites, ALD of aluminium species enables the generation of acid catalytic activity.

Mass redistribution causes the structural richness of ion-irradiated surfaces.

We show that the "sputter patterning" topographical instability is determined by the effects of ion impact-induced prompt atomic redistribution and that erosion--the consensus predominant cause--is essentially irrelevant. We use grazing incidence small angle x-ray scattering to measure in situ the damping of noise or its amplification into patterns via the linear dispersion relation. A model based on the effects of impact-induced redistribution of those atoms that are not sputtered away explains both the observed ultrasmoothening at low angles from normal incidence and the instability at higher angles.

Direct measurement of microstructural avalanches during the martensitic transition of cobalt using coherent x-ray scattering.

Heterogeneous microscale dynamics in the martensitic phase transition of cobalt is investigated with real-time x-ray scattering. During the transformation of the high-temperature face-centered cubic phase to the low-temperature hexagonal close-packed phase, the structure factor evolution suggests that an initial rapid local transformation is followed by a slower period during which strain relaxes. Coherent x-ray scattering measurements performed during the latter part of the transformation show that the kinetics is dominated by discontinuous sudden changes-avalanches. The spatial size of observed avalanches varies widely, from 100 nm to 10 µm, the size of the x-ray beam. An empirical avalanche amplitude quantifies this behavior, exhibiting a power-law distribution. The avalanche rate decreases with inverse time since the onset of the transformation.

Type A quadricuspid aortic valve and ascending aorta aneurysm: a rare combination.

Quadricuspid aortic valve (QAV) is a rare congenital anomaly associated with aortic valve insufficiency and significant morbidity, and requires the replacement or, rarely, the repair of the malfunctioning heart valve. A QAV associated with an ascending aorta aneurysm is an extremely rare anatomic combination with a hypothetical, but not clear, shared embryological etiology. To date, only two cases of type B QAV with ascending aorta aneurysm have been reported. Herein is described the first ever case of a 38-year-old male suffering from severe symptomatic aortic valve regurgitation due to a type A QAV, associated with an ascending aorta aneurism, who underwent a successful combined replacement of the aortic valve and ascending aorta.

Transapical aortic valve implantation following a left pneumonectomy.

Transapical transcatheter aortic valve implantation is an emerging technique for high-risk patients with symptomatic aortic valve stenosis, peripheral vascular disease, and severe concomitant comorbidities. However, a previous major surgical intervention involving the left hemithorax and the lung has always been considered a technical surgical challenge or even a potential contraindication for this minimally invasive procedure. With this report, we demonstrate, for the first time, that a previous left pneumonectomy followed by mediastinal radiotherapy does not affect the feasibility of transapical transcatheter aortic valve implantation, and we discuss the preoperative workup and the peculiar intraoperative cardiac imaging and surgical assessment.

Catheter-based treatment of the dissected ascending aorta: a systematic review.

OBJECTIVES: Type A aortic dissection requires immediate surgical repair. Despite improvements in surgery and anaesthesia, there is still a considerable risk when high-risk patients are concerned. Less invasive endovascular treatments are under evaluation. We investigated the current status of catheter-based treatment for type A aortic dissection with the entry tear located in the ascending aorta. METHODS: A PubMed search was supplemented by searching through bibliographies and key articles. Demographics, risk score, stent graft detail, access route, mortality, cause of death, complications, reinterventions and follow-up data were extracted and analysed. RESULTS: Thirty-one articles (7 retrospective reports; 24 case reports/series) were included in the study. In total, 104 patients (mean age 71 ± 14 years) received endovascular treatment for acute (63) or chronic (41) type A dissection. A history of a major cardiac or aortic operation was present in 29 patients. The mean EuroSCORE II was 30 ± 20 in 4 reports. A total of 114 stent grafts were implanted: 'off-the-shelf', 65/114; custom made, 12/114; and modified, 7/114. Hospital complications included intraprocedural conversion to open surgery (2/104), stroke (2/104), coronary stenting (2/104), early endoleak (9/104) and repeat aortic endovascular treatment for endoleak (5/104). Hospital mortality was 10% (intraoperative death 2/104). Mean duration of follow-up time was 21 ± 21 months (range 1-81 months); follow-up data were available for 86 patients: 10 patients died of non-aortic-related causes; reintervention for aortic disease (endovascular repair or open surgery) was performed in 8 patients. CONCLUSIONS: Catheter-based ascending aorta repair for type A aortic dissection with the entry tear in the ascending aorta can be considered in carefully selected high-risk patients. Further analysis and specifically designed devices are required.

Endovascular treatment of the dissected proximal aortic arch: a systematic review.

OBJECTIVES: Surgical repair of aortic dissection involving the proximal aortic arch is associated with higher morbidity and mortality, in particular when elderly high-risk patients are concerned. Endovascular treatments for this disease are under evaluation and some reports exist. We investigated the current use of catheter-based treatments for the dissected proximal aortic arch repair. METHODS: We searched in PubMed and MEDLINE databases up to the end of June 2020 for studies on endovascular treatment of the dissected proximal aortic arch. Data on demographic, procedure and stent graft (SG) details, access route, mortality with cause of death, complications and follow-up were extracted. A systematic review on the employed technology, procedure and outcome was performed. RESULTS: A total number of 15 articles (13 retrospective reports and 2 case reports) were deemed eligible and were included in the study. In total, 140 patients (mean age: 56.7 years in 106 cases) received endovascular treatments for the dissected proximal aortic arch (unspecific aortic dissection: 14; acute and subacute type A aortic dissection: 88; chronic type A aortic dissection: 23; type B aortic dissection with retrograde type A dissection: 15). The procedure strategy included unspecific thoracic endovascular aorta repair (TEVAR) (n = 8), TEVAR + supra-aortic debranching (n = 2), TEVAR + cervical bypass (n = 8), TEVAR + periscope SG (n = 12), TEVAR + chimney graft (n = 8), TEVAR + branched SG (n = 21) and TEVAR + fenestration (n = 81). Procedural success rate was 95.6% for 116 reported cases. Complications included endoleaks (postoperative: 2; late: 5), stroke (n = 4), late SG-induced new entry (n = 3) and new false lumen formation (n = 1). Hospital mortality was 5% (6 cases) in 13 reports (120 patients). The mean follow-up time was 26.2 ± 29.4 months and 2 patients died during follow-up. CONCLUSIONS: As an alternative to surgery for high-risk patients with a dissected proximal aortic arch, the endovascular treatment seems to be promising in highly selected cases. Further studies with long-term results and specifically designed devices are required to standardize this approach.

Probing the subcellular nanostructure of engineered human cardiomyocytes in 3D tissue.

The structural and functional maturation of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) is essential for pharmaceutical testing, disease modeling, and ultimately therapeutic use. Multicellular 3D-tissue platforms have improved the functional maturation of hiPSC-CMs, but probing cardiac contractile properties in a 3D environment remains challenging, especially at depth and in live tissues. Using small-angle X-ray scattering (SAXS) imaging, we show that hiPSC-CMs matured and examined in a 3D environment exhibit a periodic spatial arrangement of the myofilament lattice, which has not been previously detected in hiPSC-CMs. The contractile force is found to correlate with both the scattering intensity (R 2 = 0.44) and lattice spacing (R 2 = 0.46). The scattering intensity also correlates with lattice spacing (R 2 = 0.81), suggestive of lower noise in our structural measurement than in the functional measurement. Notably, we observed decreased myofilament ordering in tissues with a myofilament mutation known to lead to hypertrophic cardiomyopathy (HCM). Our results highlight the progress of human cardiac tissue engineering and enable unprecedented study of structural maturation in hiPSC-CMs.