Comparison of batch and continuous multi-column capture of monoclonal antibodies with convective diffusive membrane adsorbers.

Protein A affinity membrane adsorbers are a promising alternative to resins to intensify the manufacturing of monoclonal antibodies. This study examined the process performance of convective diffusive membrane adsorbers operated in batch and continuous multi-column mode. Therefore, three different processes were compared regarding membrane utilization, productivity, and buffer consumption: the batch process, the rapid cycling parallel multi-column chromatography process, and the rapid cycling simulated moving bed process. The influence of the monoclonal antibody loading concentration (between 0.5 g L-1 and 5.2 g L-1) and the loading flow rate (between 1.25 MV min-1 and 10 MV min-1) on the monoclonal antibody binding behavior of the membrane adsorber were studied with breakthrough curve experiments. The determined breakthrough curves were used to calculate the monoclonal antibody dynamic binding capacity, the duration of the loading steps for each process, and the number of required membrane adsorbers for the continuous processes rapid cycling parallel multi-column chromatography and rapid cycling simulated moving bed. The highest productivity for the batch (176 g L-1 h-1) and rapid cycling parallel multi-column chromatography process (176 g L-1 h-1) was calculated for high monoclonal antibody loading concentrations and low loading flow rates. In contrast, the rapid cycling simulated moving bed process achieved the highest productivity (217 g L-1 h-1) for high monoclonal antibody loading concentrations and loading flow rates. Furthermore, due to the higher membrane utilization, the buffer consumption of the rapid cycling simulated moving bed process (1.1 L g-1) was up to 1.9 times lower than that of the batch or rapid cycling parallel multi-column chromatography operation (2.1 L g-1).

Inferring malignancy grade of soft tissue sarcomas from magnetic resonance imaging features: A systematic review.

PURPOSE: Systematic reviews on the grading of STS using MRI are lacking. This review analyses the role of different MRI features in inferring the histological grade of STS. MATERIALS AND METHODS: A systematic review was conducted and is reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) checklist. The electronic databases of PubMed/MEDLINE were systematically searched for literature addressing the correlation of MRI findings in soft tissue sarcoma with tumor grade. As keywords "MRI", "magnetic resonance imaging", "sarcoma", "grade", "grading", and "FNCLCC" have been selected. RESULTS: 14 studies have been included in this systematic review. Tumor size (p = 0.015 (51 patients) to p = 0.81 (36 patients)), tumor margin (p < 0.001 (95 patients) to 0.93 (36 patients)), necrosis (p = 0.004 (50 patients) to p = 0.65 (95 patients)), peritumoral edema (p = 0.002 (130 patients) to p = 0.337 (40 patients)), contrast enhancement (p < 0.01 (50 patients) to 0.019 (51 patients)) and polycyclic/multilobulated tumor configuration (p = 0.008 (71 patients)) were significantly associated with STS malignancy grade in most of the included studies. Heterogeneity in T2w images (p = 0.003 (130 patients) to 0.202 (40 patients)), signal intensity in T1w images/ hemorrhage (p = 0.02 (130 patients) to 0.5 (31 patients)), peritumoral contrast enhancement (p < 0.001 (95 patients) to 0.253 (51 patients)) and tumoral diffusion restriction (p = 0.01 (51 patients) to 0.53 (52 patients)) were regarded as significantly associated with FNCLCC grade in some of the studies which investigated these features. Most other MRI features were not significant. CONCLUSION: Several MRI features, such as tumor size, necrosis, peritumoral edema, peritumoral contrast enhancement, intratumoral contrast enhancement, and polycyclic/multilobulated tumor configuration may indicate the malignancy grade of STS. However, further studies are needed to gain consensus.

Continuous multi-column capture of monoclonal antibodies with convective diffusive membrane adsorbers.

Downstream processing is the bottleneck in the continuous manufacturing of monoclonal antibodies (mAbs). To overcome throughput limitations, two different continuous processes with a novel convective diffusive protein A membrane adsorber (MA) were investigated: the rapid cycling parallel multi-column chromatography (RC-PMCC) process and the rapid cycling simulated moving bed (RC-BioSMB) process. First, breakthrough curve experiments were performed to investigate the influence of the flow rate on the mAb dynamic binding capacity and to calculate the duration of the loading steps. In addition, customized control software was developed for an automated MA exchange in case of pressure increase due to membrane fouling to enable robust, uninterrupted, and continuous processing. Both processes were performed for 4 days with 0.61 g L-1 mAb-containing filtrate and process performance, product purity, productivity, and buffer consumption were compared. The mAb was recovered with a yield of approximately 90% and productivities of 1010 g L-1 d-1 (RC-PMCC) and 574 g L-1 d-1 (RC-BioSMB). At the same time, high removal of process-related impurities was achieved with both processes, whereas the buffer consumption was lower for the RC-BioSMB process. Finally, the attainable productivity for perfusion bioreactors of different sizes with suitable MA sizes was calculated to demonstrate the potential to operate both processes on a manufacturing scale with bioreactor volumes of up to 2000 L.

Agar plate-based activity assay for easy and fast screening of recombinant Pichia pastoris expressing unspecific peroxygenases.

Unspecific peroxygenases (UPOs) are promising biocatalysts that catalyze oxyfunctionalization reactions without the need for costly cofactors. Pichia pastoris (reclassified as Komagataella phaffii) is considered an attractive host for heterologous expression of UPOs. However, integration of UPO-expression cassettes into the genome via a single cross-over yields recombinant Pichia transformants with different UPO gene copy numbers resulting in different expression levels. Selection of the most productive Pichia transformants by a commonly used screening in liquid medium in 96-well plates is laborious and lasts up to 5 days. In this work, we developed a simple two-step agar plate-based assay to screen P. pastoris transformants for UPO activity with less effort, within shorter time, and without automated screening devices. After cell growth and protein expression on agar plates supplemented with methanol and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), an additional top agar layer supplemented with ABTS and peroxide is added. UPO activity is visualized within 15 min by formation of green zones around UPO-secreting P. pastoris transformants. The assay was validated with two UPOs, AbrUPO from Aspergillus brasiliensis and evolved PaDa-I from Agrocybe aegerita. The assay results were confirmed in a quantitative 96-deep well plate screening in liquid medium.

High Open-Circuit Voltage Cs2 AgBiBr6 Carbon-Based Perovskite Solar Cells via Green Processing of Ultrasonic Spray-Coated Carbon Electrodes from Waste Tire Sources.

Invited for this month cover is the group of Teresa Gatti at the Justus Liebig University (JLU) in Giessen, Germany, the group of Federico Bella at Politecnico di Torino (POLITO), Italy, and the group of Francesco Lamberti at the University of Padova (UNIPD), also in Italy. The image shows how waste tires can be converted in a conductive carbon powder that undergoes a green processing step to produce carbon electrodes for lead-free perovskite solar cells. Similar devices can be employed to harvest indoor light in order to power the Internet of Things (IoT) ecosystem. The Research Article itself is available at 10.1002/cssc.202201590.

High Open-Circuit Voltage Cs2 AgBiBr6 Carbon-Based Perovskite Solar Cells via Green Processing of Ultrasonic Spray-Coated Carbon Electrodes from Waste Tire Sources.

Costs and toxicity concerns are at the center of a heated debate regarding the implementation of perovskite solar cells (PSCs) into commercial products. The first bottleneck could be overcome by eliminating the top metal electrode (generally gold) and the underlying hole transporting material and substituting both with one single thick layer of conductive carbon, as in the so-called carbon-based PSCs (C-PSCs). The second issue, related to the presence of lead, can be tackled by resorting to other perovskite structures based on less toxic metallic components. An interesting case is that of the double perovskite Cs2 AgBiBr6 , which at present still lacks the outstanding optoelectronic performances of the lead-based counterparts but is very stable to environmental factors. In this work, the processing of carbon electrodes onto Cs2 AgBiBr6 -based C-PSCs was reported, starting from an additive-free isopropanol ink of a carbon material obtained from the hydrothermal recycling of waste tires and employing a high-throughput ultrasonic spray coating method in normal environmental conditions. Through this highly sustainable approach that ensures a valuable step from an end-of-life to an end-of-waste status for used tires, devices were obtained delivering a record open circuit voltage of 1.293 V, which might in the future represent ultra-cheap solutions to power the indoor Internet of Things ecosystem.

Tuning the optical properties of 2D monolayer silver-bismuth bromide double perovskite by halide substitution.

Silver-bismuth double perovskites are promising replacement materials for lead-based ones in photovoltaic (PV) devices due to the lower toxicity and enhanced stability to environmental factors. In addition, they might even be more suitable for indoor PV, due to the size of their bandgap better matching white LEDs emission. Unfortunately, their optoelectronic performance does not reach that of the lead-based counterparts, because of the indirect nature of the band gap and the high exciton binding energy. One strategy to improve the electronic properties is the dimensional reduction from the 3D to the 2D perovskite structure, which features a direct band gap, as it has been reported for 2D monolayer derivates of Cs2AgBiBr6obtained by substituting Cs+cations with bulky alkylammonium cations. However, a similar dimensional reduction also brings to a band gap opening, limiting light absorption in the visible. In this work, we report on the achievement of a bathochromic shift in the absorption features of a butylammonium-based silver-bismuth bromide monolayer double perovskite through doping with iodide and study the optical properties and stability of the resulting thin films in environmental conditions. These species might constitute the starting point to design future sustainable materials to implement as active components in indoor photovoltaic devices used to power the IoT.

Complex Evolution of Light-Dependent Protochlorophyllide Oxidoreductases in Aerobic Anoxygenic Phototrophs: Origin, Phylogeny, and Function.

Light-dependent protochlorophyllide oxidoreductase (LPOR) and dark-operative protochlorophyllide oxidoreductase are evolutionary and structurally distinct enzymes that are essential for the synthesis of (bacterio)chlorophyll, the primary pigment needed for both anoxygenic and oxygenic photosynthesis. In contrast to the long-held hypothesis that LPORs are only present in oxygenic phototrophs, we recently identified a functional LPOR in the aerobic anoxygenic phototrophic bacterium (AAPB) Dinoroseobacter shibae and attributed its presence to a single horizontal gene transfer event from cyanobacteria. Here, we provide evidence for the more widespread presence of genuine LPOR enzymes in AAPBs. An exhaustive bioinformatics search identified 36 putative LPORs outside of oxygenic phototrophic bacteria (cyanobacteria) with the majority being AAPBs. Using in vitro and in vivo assays, we show that the large majority of the tested AAPB enzymes are genuine LPORs. Solution structural analyses, performed for two of the AAPB LPORs, revealed a globally conserved structure when compared with a well-characterized cyanobacterial LPOR. Phylogenetic analyses suggest that LPORs were transferred not only from cyanobacteria but also subsequently between proteobacteria and from proteobacteria to Gemmatimonadetes. Our study thus provides another interesting example for the complex evolutionary processes that govern the evolution of bacteria, involving multiple horizontal gene transfer events that likely occurred at different time points and involved different donors.

Lanthanide-Induced Photoluminescence in Lead-Free Cs2AgBiBr6 Bulk Perovskite: Insights from Optical and Theoretical Investigations.

Emphasis was recently placed on the Cs2AgBiBr6 double perovskite as a possible candidate to substitute toxic lead in metal halide perovskites. However, its poor light-emissive features currently make it unsuitable for solid-state lighting. Lanthanide doping is an established strategy to implement luminescence in poorly emissive materials, with the additional advantage of fine-tuning the emission wavelength. We discuss here the impact of Eu and Yb doping on the optical properties of Cs2AgBiBr6 thin films, obtained from the solution processing of hydrothermally synthesized bulk crystalline powders, by combining experiments and density functional theory calculations. Eu(III) incorporation does not lead to the characteristic 5D0 → 7F2 emission feature at 2 eV, while only a weak trap-assisted sub-band gap radiative emission is reported. Oppositely, we demonstrate that incorporated Yb(III) leads to an intense and exclusive photoluminescence emission in the near-infrared as a result of the efficient sensitization of the lanthanide 2F5/2 → 2F7/2 transition.

Portal hypertensive gastropathy is associated with iron deficiency anemia.

BACKGROUND AND AIMS: Portal hypertensive gastropathy (PHG) is common in patients with cirrhosis and may cause bleeding. This study systematically explored the independent impact of patient characteristics, portal hypertension and hepatic dysfunction on PHG severity and associated anemia. METHODS: Patients with cirrhosis undergoing endoscopy were included in this retrospective analysis and PHG was endoscopically graded as absent, mild or severe. Clinical and laboratory parameters and hepatic venous pressure gradient (HVPG) were assessed with respect to an association with severity of PHG. RESULTS: A total of 110 patients (mean age: 57 years, 69% male) with mostly alcoholic liver disease (49%) or viral hepatitis (30%) were included: 15 (13.6%) patients had no PHG, 59 (53.6%) had mild PHG, and 36 (32.7%) had severe PHG. Severe PHG was significantly associated with male sex (83.3% vs. 62.2% in no or mild PHG; p = 0.024) and higher Child-Turcotte-Pugh (CTP) stage (CTP-C: 38.9% vs. 27.0% in no or mild PHG; p = 0.030), while MELD was similar (p = 0.253). Patients with severe PHG had significantly lower hemoglobin values (11.2 ± 0.4 g/dL vs. 12.4 ± 0.2 g/dL; p = 0.008) and a higher prevalence of iron-deficiency anemia (IDA: 48.5% vs. 26.9%; p = 0.032). Interestingly, HVPG was not significantly higher in severe PHG (median 20 mm Hg) vs. mild PHG (19 mm Hg) and no PHG (18 mm Hg; p = 0.252). On multivariate analysis, CTP score (odds ratio, OR: 1.25, 95% confidence interval, CI 1.02-1.53; p = 0.033) was independently associated with severe PHG, while only a trend towards an independent association with IDA was observed (OR: 2.28, 95% CI 0.91-5.72; p = 0.078). CONCLUSION: The CTP score but not HVPG or MELD were risk factors for severe PHG. Importantly, anemia and especially IDA are significantly more common in patients with severe PHG.

Equilibrium between a Droplet and Surrounding Vapor: A Discussion of Finite Size Effects.

In a theoretical description of homogeneous nucleation one frequently assumes an "equilibrium" coexistence of a liquid droplet with surrounding vapor of a density exceeding that of a saturated vapor at bulk vapor-liquid two-phase coexistence. Thereby one ignores the caveat that in the thermodynamic limit, for which the vapor would be called supersaturated, such states will at best be metastable with finite lifetime, and thus not be well-defined within equilibrium statistical mechanics. In contrast, in a system of finite volume stable equilibrium coexistence of droplet and supersaturated vapor at constant total density is perfectly possible, and numerical analysis of equilibrium free energies of finite systems allows to obtain physically relevant results. In particular, such an analysis can be used to derive the dependence of the droplet surface tension γ( R) on the droplet radius R by computer simulations. Unfortunately, however, the precision of the results produced by this approach turns out to be seriously affected by a hitherto unexplained spurious dependence of γ( R) on the total volume V of the simulation box. These finite size effects are studied here for the standard Ising/lattice gas model in d = 2 dimensions and an Ising model on the face-centered cubic lattice with 3-spin interaction, lacking symmetry between vapor and liquid phases. There also the analogous case of bubbles surrounded by undersaturated liquid is treated. It is argued that (at least a large part of) the finite size effects result from the translation entropy of the droplet or bubble in the system. This effect has been shown earlier to occur also for planar interfaces for simulations in the slab geometry. Consequences for the estimation of the Tolman length are briefly discussed. In particular, we find clear evidence that in d = 2 the leading correction of the curvature-dependent interface tension is a logarithmic term, compatible with theoretical expectations, and we show that then the standard Tolman-style analysis is inapplicable.

The ensemble switch method for computing interfacial tensions.

We present a systematic thermodynamic integration approach to compute interfacial tensions for solid-liquid interfaces, which is based on the ensemble switch method. Applying Monte Carlo simulations and finite-size scaling techniques, we obtain results for hard spheres, which are in agreement with previous computations. The case of solid-liquid interfaces in a variant of the effective Asakura-Oosawa model and of liquid-vapor interfaces in the Lennard-Jones model are discussed as well. We demonstrate that a thorough finite-size analysis of the simulation data is required to obtain precise results for the interfacial tension.

Logarithmic finite-size effects on interfacial free energies: phenomenological theory and Monte Carlo studies.

The computation of interfacial free energies between coexisting phases (e.g., saturated vapor and liquid) by computer simulation methods is still a challenging problem due to the difficulty of an atomistic identification of an interface and interfacial fluctuations on all length scales. The approach to estimate the interfacial tension from the free-energy excess of a system with interfaces relative to corresponding single-phase systems does not suffer from the first problem but still suffers from the latter. Considering d-dimensional systems with interfacial area L(d-1) and linear dimension L(z) in the direction perpendicular to the interface, it is argued that the interfacial fluctuations cause logarithmic finite-size effects of order ln(L)/L(d-1) and order ln(L(z))/L(d-1), in addition to regular corrections (with leading-order const/L(d-1)). A phenomenological theory predicts that the prefactors of the logarithmic terms are universal (but depend on the applied boundary conditions and the considered statistical ensemble). The physical origin of these corrections are the translational entropy of the interface as a whole, "domain breathing" (coupling of interfacial fluctuations to the bulk order parameter fluctuations of the coexisting domains), and capillary waves. Using a new variant of the ensemble switch method, interfacial tensions are found from Monte Carlo simulations of d = 2 and d = 3 Ising models and a Lennard-Jones fluid. The simulation results are fully consistent with the theoretical predictions.

Determination of the origin and magnitude of logarithmic finite-size effects on interfacial tension: role of interfacial fluctuations and domain breathing.

The ensemble-switch method for computing wall excess free energies of condensed matter is extended to estimate the interface free energies between coexisting phases very accurately. By this method, system geometries with linear dimensions L parallel and Lz perpendicular to the interface with various boundary conditions in the canonical or grand canonical ensemble can be studied. Using two- and three-dimensional Ising models, the nature of the occurring logarithmic finite-size corrections is studied. It is found crucial to include interfacial fluctuations due to "domain breathing."

Monte Carlo tests of nucleation concepts in the lattice gas model.

The conventional theory of homogeneous and heterogeneous nucleation in a supersaturated vapor is tested by Monte Carlo simulations of the lattice gas (Ising) model with nearest-neighbor attractive interactions on the simple cubic lattice. The theory considers the nucleation process as a slow (quasistatic) cluster (droplet) growth over a free energy barrier ΔF(*), constructed in terms of a balance of surface and bulk term of a critical droplet of radius R(*), implying that the rates of droplet growth and shrinking essentially balance each other for droplet radius R=R(*). For heterogeneous nucleation at surfaces, the barrier is reduced by a factor depending on the contact angle. Using the definition of physical clusters based on the Fortuin-Kasteleyn mapping, the time dependence of the cluster size distribution is studied for quenching experiments in the kinetic Ising model and the cluster size ℓ(*) where the cluster growth rate changes sign is estimated. These studies of nucleation kinetics are compared to studies where the relation between cluster size and supersaturation is estimated from equilibrium simulations of phase coexistence between droplet and vapor in the canonical ensemble. The chemical potential is estimated from a lattice version of the Widom particle insertion method. For large droplets it is shown that the physical clusters have a volume consistent with the estimates from the lever rule. Geometrical clusters (defined such that each site belonging to the cluster is occupied and has at least one occupied neighbor site) yield valid results only for temperatures less than 60% of the critical temperature, where the cluster shape is nonspherical. We show how the chemical potential can be used to numerically estimate ΔF(*) also for nonspherical cluster shapes.

Nanoporous membranes produced from polycrystalline Ni-based superalloys.

Porous metal membranes are produced from a two phase system in which the discrete cubic gamma'-precipitates connect during self assembly. In the so called rafting process the cubic particles start to coarsen and finally create a network within the gamma-matrix. In a following electrochemical leaching process one of the phases can be removed leaving the nanoporous membrane. So far, single crystalline alloys have been used for producing thin nanoporous membranes. Now research is in progress to produce the nanoporous membranes from polycrystalline alloys in a creep process. A modification of the commercially available alloy Nimonic 115 was used for these membranes. The permeability of these membranes was proven in a gas-flow test.

Calcium metabolism in adults with severe aortic valve stenosis and preserved renal function.

Data suggest a link of aortic stenosis (AS) with calcium and bone metabolism. To further investigate this, the following parameters were analyzed in 38 patients with severe AS and in 38 age- and gender-matched controls, without obstructive coronary artery disease and with preserved renal function: calcium, phosphate, 1,25(OH(2))-vitamin D(3), intact parathyroid hormone (iPTH), and osteoprotegerin. Patients with AS had significantly higher serum levels of calcium (2.63 +/- 0.28 vs 2.48 +/- 0.23 mmol/L, p <0.01) and phosphate (1.56 +/- 0.33 vs 1.38 +/- 0.26 mmol/L, p <0.01) and increased calcium-phosphorus products (4.16 +/- 1.13 vs 3.44 +/- 0.89 mmol/L(2), p = 0.003). Notably, the iPTH concentration in the AS group was lower, and significantly more patients in the AS group had levels less than the study median of 60 ng/L. Osteoprotegerin was elevated in patients with AS, confirming reports in other populations (9.94 +/- 5.96 vs 6.73 +/- 4.28 pmol/L, p = 0.009). The relations of several parameters to iPTH were also altered (AS vs controls): calcium and iPTH, 0.071 +/- 0.034 versus 0.046 +/- 0.023, p <0.0001; phosphate and iPTH, 0.042 +/- 0.020 versus 0.025 +/- 0.013, p <0.0001; vitamin D and iPTH, 0.99 +/- 0.61 versus 0.63 +/- 0.46, p = 0.006; and osteoprotegerin and iPTH, 0.24 +/- 0.15 versus 0.12 +/- 0.09, p <0.0001. In conclusion, these data support a hypothesis connecting (severe) AS to altered calcium and bone homeostasis.

Parathyroid hormone gene variant and calcific aortic stenosis.

BACKGROUND AND AIM OF THE STUDY: Calcific aortic stenosis (AS) is the most frequently acquired valvular disease of the elderly in the Western world. A genetic background for AS has been proposed. The deposition of calcium hydroxyapatite is the key problem of valve calcification; vitamin D and parathyroid hormone are major factors in calcium homeostasis. The vitamin D receptor (VDR) gene and parathyroid hormone (PTH) gene variants were selected as candidate genes. METHODS: A total of 538 patients with severe calcific AS (identified echocardiographically) were characterized by left heart catheterization. A group of 536 patients in whom heart disease had been excluded by left heart catheterization served as a control population. The cardiovascular risk profile was assessed, and three gene variants were analyzed, namely VDR rs1544410, VDR rs1073810, and PTH rs6254. RESULTS: Patients with AS were found to have a higher prevalence of the PTH AA genotype (108 +/- 20.1% versus 71 +/- 13.2%; p = 0.007), while the VDR gene revealed a marginal, but statistically non-significant, association. The age and risk profile was similar in both groups. CONCLUSION: To date, the association of the PTH gene variant has been the only positive association studied in patients with AS in a large population. Hence, the polymorphism is within an intron; the molecular mechanisms of altered gene expression should undergo further investigation.

Advanced speckle tracking echocardiography allowing a three-myocardial layer-specific analysis of deformation parameters.

AIMS: Different layers of myocardium may contribute differently to myocardial deformation. Speckle tracking based on high resolution two-dimensional (2D) echocardiography has been used to define myocardial deformation parameters of whole left ventricular (LV) segments. This study evaluated with a Novell analysis modality allowing layer-specific analysis of deformation if there are differences in myocardial deformation between different layers of myocardium. METHODS AND RESULTS: In 30 normal subjects and 20 patients with impaired myocardial function 2D parasternal short-axis echocardiographic views of the LV were acquired at the basal, mid-papillary, and apical levels. Using a Novell automatic frame-to-frame tracking system of natural acoustic echocardiographic markers (EchoPAC, GE Ultrasound, Haifa, Israel), circumferential strain (CS) and strain rate of the endocardial, mid-myocardial and epicardial layer was calculated for each LV segment in an 18-segment model. Wall motion for each segment was defined as normokinetic, hypokinetic, and akinetic based on 2D echocardiographic images. Peak systolic CS could be analysed in 837 segments (93%). In the normal subjects peak systolic CS was greatest in the endocardial layer, lower in the mid-myocardial layer, and lowest in the epicardial layer (38.1+/-9.0%, 28.9+/-9.3%, and 24.0+/-9.4%, respectively, P<0.001). In the patients with impaired LV function 151 segments were hypokinetic and 92 segments akinetic by visual analysis. In all myocardial layers peak systolic CS and strain rate decreased with decreasing segmental function. CONCLUSION: Decreasing myocardial deformation from endocardial to epicardial layers can be demonstrated with the use of an advanced analysis system allowing definition of deformation parameters for three myocardial layers. Myocardial deformation is reduced in all layers of segments with impaired wall motion.

Relation of optimal lead positioning as defined by three-dimensional echocardiography to long-term benefit of cardiac resynchronization.

We sought to define the impact of echocardiographically defined left ventricular (LV) lead position on the efficacy of cardiac resynchronization therapy (CRT) in a serial study using 3-dimensional echocardiography. Fifty-eight consecutive patients (53+/-9 years of age; 37 men) with heart failure were included in the study. Echocardiograms were obtained before CRT, within 7 days after implantation, and at 12+/-2 months of follow-up using a 3-dimensional digital ultrasound scanner (iE33, Philips, Andover, Massachusetts). Analysis of the temporal course of contraction in 16 LV segments was performed offline using a semiautomatic contour tracing software (LV Analysis, TomTec, Unterschleissheim, Germany). Based on the resulting volume/time curves the segment with the latest minimum of systolic volume in each patient was identified preoperatively (segment A). In addition, the temporal difference between the pre- and postoperative (within 7 days) minimum of systolic volume was determined for each segment. The segment with the longest temporal difference was defined to show the greatest effect of CRT. Location of the LV lead tip was assumed to be within this segment (segment B). LV lead position was defined as optimal when segments A and B were equal and as nonoptimal when they were far from each other. Using this definition, 26 patients had a nonoptimal and 32 patients an optimal LV lead position. Before CRT ejection fraction (32+/-4% vs 31+/-6%), LV end-systolic and end-diastolic volumes (242+/-92 vs 246+/-88 ml, 315+/-82 vs 323+/-90 ml), and peak oxygen consumption (14.3+/-1.4 vs 14.6+/-1.5 ml/min/kg) were equal in the 2 groups. At 12+/-2 months of follow-up, patients with an assumed optimal LV lead position showed greater increases of ejection fraction (10+/-2% vs 6+/-3%) and peak oxygen consumption (2.4+/-0.3 vs 1.5+/-0.4 ml/min/kg) and greater decreases of LV end-systolic (32+/-7 vs 21+/-5 ml) and end-diastolic (20+/-7 vs 13+/-6 ml) volumes. In conclusion, correspondence of the segment with the latest preoperative LV contraction with the segment with the greatest effect based on CRT results in a significantly greater benefit of ejection fraction and peak oxygen consumption and a greater improvement in LV remodeling. Thus, there is an optimal LV lead position that should be obtained.