Risk factors of readmission and the impact of outpatient management in heart failure patients: A national study in Japan.

AIMS: Heart failure is a significant disease, and its high readmission rate is a big concern. We must identify readmission risk factors and optimize outpatient management to prevent them. This study aims to investigate the readmission risk factors, including outpatient management represented by the number of outpatient visits, and to identify the factors related to frequent outpatient visits. METHODS AND RESULTS: We used the diagnosis-procedure-combination database between April 2016 and March 2022. Based on the number of outpatient visits within 60 days after discharge, we categorized patients into <1 visits/month, (1<, ≦2) visits/month, and <2 visits/month and observed the occurrence of 60 days readmission. We performed multiple logistic regression analyses to reveal the readmission risk factors and the association between the number of outpatient visits and readmission. As a subgroup analysis, we conducted the same research in the low- and high-readmission risk groups. We compared medical contents between (1<, ≦2) visits/month and <2 visits/month. We analysed 101 239 patients and identified the following factors as a risk of readmission: older age (P < 0.001), female (P = 0.009), longer length-of-hospital-stay (P < 0.001), artificial ventilator (P < 0.001), tolvaptan (P < 0.001), top 50% dosage of loop diuretics (P = 0.036), bottom 50% dosage of class III antiarrhythmic agents (P < 0.001), hypertension (P = 0.005), atrial fibrillation (P < 0.001), dilated cardiomyopathy (P < 0.001), valvular disease (P = 0.021), myocardial infarction (P < 0.001), diabetes (P < 0.001), and renal disease (P < 0.001). We revealed that the risk of readmission increases in <2 visits/month compared to (1<, ≦2) visits/month (P < 0.001), whereas the risk of readmission decreases in ≦1 visits/month compared with (1<, ≦2) visits/month (P < 0.001). In the subgroup analysis, we found the possibility that some risk factors are specific to the subgroup. We identified that the following factors were related to frequent outpatient visits: older age (P < 0.001), home medical care (P = 0.007), tolvaptan (P < 0.001), top 50% dosage of loop diuretics (P < 0.001), diabetes (P < 0.001), renal disease (P = 0.009), 0-2 weeks follow-up (P < 0.001), 2-4 weeks follow-up (P < 0.001), cardiac rehabilitation (P < 0.001), and echocardiography (P < 0.001). CONCLUSIONS: This study comprehensively identified risk factors for readmission and found outpatient visit is personalized by readmission risk. There is still room to optimize outpatient management. We suggest optimizing outpatient management according to our identified characteristics.

Risk Factors with 30-Day Readmission and the Impact of Length of Hospital Stay on It in Patients with Heart Failure: A Retrospective Observational Study Using a Japanese National Database.

Heart failure is a major disease, and its 30-day readmission (readmission within 30-day after discharge) negatively impacts patients and society. Thus, we need to stratify the risk and prevent readmission. We aimed to investigate risk factors associated with 30-day readmission and examine the impact of length of hospital stay (LOS) on 30-day readmission. Using the Diagnosis-Procedure-Combination database from April 2018 to March 2021, we conducted multiple logistic regression to investigate risk factors with 30-day readmission. Also, we conducted subgroup analysis in the short LOS group. To examine the association between LOS and 30-day readmission, we performed propensity score matching between the short and middle LOS groups. As a result, we categorized 10,283 patients and 169,842 patients into the readmission group and the no-readmission group. We identified the following factors as the risk of readmission: short LOS, female, smoking, older age, lower body mass index, lower barthel index, artificial ventilator, beta-blockers, thiazides, tolvaptan, loop diuretics, carperitides, class Ⅲ antiarrhythmic agents, myocardial infarction, diabetes, renal disease, atrial fibrillation, dilated cardiomyopathy, and discharge to home. As a subgroup analysis in the short LOS group, we revealed that the short LOS group risk factors differed from overall. After propensity score matching in the short LOS group and middle LOS group, 37,199 pairs were matched, and we revealed that shorter LOS increases the risk of readmission. These results demonstrated that shortened LOS increases 30-day readmission, and risk factors are unique to each LOS. We suggest stratifying the readmission risk and being careful with early discharge.

Example-Based Multispectral Photometric Stereo for Multi-Colored Surfaces.

A photometric stereo needs three images taken under three different light directions lit one by one, while a color photometric stereo needs only one image taken under three different lights lit at the same time with different light directions and different colors. As a result, a color photometric stereo can obtain the surface normal of a dynamically moving object from a single image. However, the conventional color photometric stereo cannot estimate a multicolored object due to the colored illumination. This paper uses an example-based photometric stereo to solve the problem of the color photometric stereo. The example-based photometric stereo searches the surface normal from the database of the images of known shapes. Color photometric stereos suffer from mathematical difficulty, and they add many assumptions and constraints; however, the example-based photometric stereo is free from such mathematical problems. The process of our method is pixelwise; thus, the estimated surface normal is not oversmoothed, unlike existing methods that use smoothness constraints. To demonstrate the effectiveness of this study, a measurement device that can realize the multispectral photometric stereo method with sixteen colors is employed instead of the classic color photometric stereo method with three colors.

Construction of Thienothiophene and Thienofuran Ring Systems via Ring Expansion of Difluorothiiranes Generated from Dithioesters.

The reaction of aryl thiophene-2-carbodithioates or thiophene-3-carbodithioates with difluorocarbene generated from BrCF2CO2Li/molecular sieves 4A produced arylsulfanylated 2,2-difluoro-3-thienylthiiranes. In the presence of lithium ion, the thiirane intermediates underwent ring expansion followed by HF elimination, leading to fluorinated thieno[3,2-b]thiophenes or thieno[2,3-b]thiophenes. The reactions of the oxygen analogues, aryl furancarbodithioates, also proceeded to afford the corresponding thieno[3,2-b]furans. Intramolecular fluorine substitution in the produced arylsulfanyl(fluoro)thienofurans allowed for another thiophene ring construction, leading to the synthesis of fused pentacyclic thienothienofurans.

Mechanical properties of muscle and tendon at high strain rate in sprinters.

The aim of the present study was to compare the mechanical properties of muscles and tendons at high strain rates between sprinters and untrained men. Fifteen sprinters and 18 untrained men participated in this study. Active muscle stiffness of the medial gastrocnemius muscle was calculated according to changes in the estimated muscle force and fascicle length during fast stretching at five different angular velocities (100, 200, 300, 500, and 600 deg·s-1 ) after submaximal isometric contractions. Stiffness and hysteresis of tendon structures were measured during ramp and ballistic contractions. Active muscle stiffness at 500 deg·s-1 (p = .070) and 600 deg·s-1 (p = .041) was greater in sprinters than untrained men, whereas no differences in those at 100, 200, and 300 deg·s-1 were found between the two groups. There were no differences in stiffness or hysteresis of tendon structures measured during ramp and ballistic contractions between the two groups. These results suggest that, for sprinters, greater active muscle stiffness at a high angular velocity is caused by exercising with a high angular velocity that is typical of their training.

Color Photometric Stereo Using Multi-Band Camera Constrained by Median Filter and Occluding Boundary.

One of the main problems faced by the photometric stereo method is that several measurements are required, as this method needs illumination from light sources from different directions. A solution to this problem is the color photometric stereo method, which conducts one-shot measurements by simultaneously illuminating lights of different wavelengths. However, the classic color photometric stereo method only allows measurements of white objects, while a surface-normal estimation of a multicolored object using this method is theoretically impossible. Therefore, it is necessary to add some constraints to estimate the surface normal of a multicolored object using the framework of the color photometric stereo method. In this study, a median filter is employed as the constraint condition of albedo, and the surface normal of the occluding boundary is employed as the constraint condition of the surface normal. By employing a median filter as the constraint condition, the smooth distribution of the albedo and normal is calculated while the sharp features at the boundary of different albedos and normals are preserved. The surface normal at the occluding boundary is propagated into the inner part of the object region, and forms the abstract shape of the object. Such a surface normal gives a great clue to be used as an initial guess to the surface normal. To demonstrate the effectiveness of this study, a measurement device that can realize the multispectral photometric stereo method with seven colors is employed instead of the classic color photometric stereo method with three colors.

Is the stiffness of human muscle and tendon structures related to muscle fiber composition in vivo?

BACKGROUND: The aim of the present study was to investigate the relationship between estimated muscle fiber composition (time-to-peak twitch torque; TPT) and muscle stiffness under passive and active conditions as well as stiffness of tendon structures in human plantar flexors. METHODS: TPT was assessed using supramaximal electrical stimulation. Active muscle stiffness in the medial gastrocnemius muscle was calculated based on changes in estimated muscle force and fascicle length during fast stretching after 50% maximal isometric contractions. Passive muscle stiffness was also calculated from estimated passive muscle force and fascicle length during slow passive stretching. Stiffness of tendon structures was determined during isometric plantar flexion using ultrasonography. RESULTS: TPT did not correlate with passive muscle stiffness (r=0.039, P=0.790), active muscle stiffness (r=0.185, P=0.203), or stiffness of tendon structures (r=-0.178, P=0.477). CONCLUSIONS: These results suggested that the muscle fiber composition of the human medial gastrocnemius muscle was not related to the mechanical properties of muscles or tendon structures.

Active muscle and tendon stiffness of plantar flexors in sprinters.

The aim of the present study was to investigate and compare muscle and tendon stiffness under active conditions in sprinters and untrained participants. In total, 14 sprinters and 24 untrained men participated in this study. Active muscle stiffness in the medial gastrocnemius muscle was calculated based on changes in estimated muscle force and fascicle length during fast stretching after submaximal isometric contractions. Tendon stiffness was determined during isometric plantar flexion using ultrasonography. No significant differences were observed in active muscle stiffness between sprinters and untrained men at any torque levels. Furthermore, no significant difference was noted in tendon stiffness between the two groups. These results suggest that muscle and tendon mechanical properties in the plantar flexors under active conditions are similar in sprinters and untrained participants.

Are the knee and ankle angles at contact related to the tendon properties of lower limbs in long distance runners?

The purpose of this study was to investigate whether the knee and ankle angles at contact during running were related to the elastic properties of tendon structures in knee extensors and plantar flexors and performance in trained long distance runners. Thirty-two highly trained male long distance runners participated in this study. Elongation of tendon structures in knee extensors and plantar flexors were measured using ultrasonography while subjects performed ramp isometric contractions up to the voluntary maximum. The relationship between estimated muscle force and tendon elongation was fit to a linear regression, the slope of which was defined as the stiffness of tendon structures. Knee and ankle angles at contact during running were determined at a speed of 18 km/h on a treadmill. Knee and ankle angles at contact were not correlated to the stiffness of tendon structures in knee extensors and plantar flexors. In addition, the best official record in a 5000-m race was not significantly correlated to knee and ankle joint angles at contact. In conclusion, knee and ankle angles at contact were not related to the elastic properties of tendon structures in knee extensors and plantar flexor and the performance of long distance running.

Passive and active muscle stiffness in plantar flexors of long distance runners.

The aim of the present study was to compare passive and active muscle stiffness and tendon stiffness between long distance runners and untrained men. Twenty long distance runners and 24 untrained men participated in this study. Active muscle stiffness in the medial gastrocnemius muscle was calculated according to changes in estimated muscle force and fascicle length during fast stretching after submaximal isometric contractions. Passive muscle stiffness was also calculated from estimated passive muscle force and fascicle length during slow passive stretching. Tendon stiffness was determined during isometric plantar flexion by ultrasonography. Passive muscle stiffness of long distance runners was significantly higher than that of untrained men (p<0.001). Active muscle stiffness at all torque levels of long distance runners was also significantly higher than that of untrained men (p<0.001). No significant difference was observed in tendon stiffness between long distance runners and untrained men (p=0.869). These results suggested that passive and active muscle stiffness were higher in long distance runners than in untrained men, whereas no significant difference was observed in tendon stiffness between the two groups.

Relationship between elastic properties of tendon structures and performance in long distance runners.

INTRODUCTION: The purpose of this study was to investigate the relationship between running performance (best official record in a 5000 m race) and elastic properties of tendon structures in knee extensors and plantar flexors among a large population of long distance runners. METHODS: Sixty-four highly trained male long distance runners participated in this study. Elongation of tendon structures in the knee extensors and plantar flexors was measured using ultrasonography while subjects performed ramp isometric contractions up to the voluntary maximum. The relationship between the estimated muscle force and tendon elongation was fit to a linear regression, the slope of which was defined as the stiffness of the tendon structures. Muscle and tendon thicknesses were also measured in the knee extensors and plantar flexors using ultrasonography. RESULTS: The best official record in a 5000 m race was negatively correlated to the stiffness of the tendon structures in the knee extensors (r = -0.341, p < 0.01), whereas it was positively correlated to the stiffness of the tendon structures in the plantar flexors (r = 0.414, p < 0.001). In both the knee extensors and plantar flexors, the other measured variables of muscle and tendon structures did not correlate with the best official record in a 5000 m race. CONCLUSION: These results suggested that better long distance runners had stiffer tendon structures in the knee extensors and more compliant ones in the plantar flexors. These results implied that tendon structures in knee extensors and plantar flexors adapted to endurance running training and contributed to running performance of long distance runners separately.

2-DOF auto-calibration for a 3D endoscope system based on active stereo.

For endoscopic medical treatment, measuring the size and shape of lesions, such as tumors, is important. We are developing a 3D endoscope system to measure the shape and size of living tissues based on active stereo. In previous works, our group attached a pattern projector outside the endoscope head. Since this increased the diameter of the endoscope, the burden and the risks of the patients would increase. In this paper, we set the pattern projector inside the instrument channel of the endoscope instead of mounting it outside, so that it can be deployed whenever required. This does not increase the size of the endoscope and facilitates the measuring process. However, since the projector is not physically fixed to the endoscope anymore prior to the operation, we propose an "auto-calibration" technique where extrinsic parameters are calibrated intra-operatively from a point marker on the projector observed simultaneously on the target surface. In the experiment, we show that the external parameters were successfully calibrated to obtain 3D reconstructions properly with the overall systems. The accuracy of the auto-calibration was validated by confirming that the epipolar constraints were kept, and a 3D reconstruction of a human tissue was demonstrated.

Relationship between Achilles tendon properties and foot strike patterns in long-distance runners.

The purpose of this study was to investigate the relationship between Achilles tendon properties and foot strike patterns in long-distance runners. Forty-one highly trained male long-distance runners participated in this study. Elongation of the Achilles tendon and aponeurosis of the medial gastrocnemius muscle were measured using ultrasonography, while the participants performed ramp isometric plantar flexion up to the voluntary maximum. The relationship between the estimated muscle force and tendon elongation during the ascending phase was fit to a linear regression, the slope of which was defined as stiffness. In addition, the cross-sectional area of the Achilles tendon was measured using ultrasonography. Foot strike patterns (forefoot, midfoot and rearfoot) during running were determined at submaximal velocity (18 km · h(-1)) on a treadmill. The number of each foot strike runner was 12 for the forefoot (29.3%), 12 for the midfoot (29.3%) and 17 for the rearfoot (41.5%). No significant differences were observed in the variables measured for the Achilles tendon among the three groups. These results suggested that the foot strike pattern during running did not affect the morphological or mechanical properties of the Achilles tendon in long-distance runners.

Volumetric display using rotating prism sheets arranged in a symmetrical configuration.

A volumetric display that creates a distortion-free three-dimensional (3D) image in midair is described. The proposed system consists of rotating prism sheets used as an optical scanner and a dihedral corner reflector array (DCRA), which is a distortion-free imaging element. Two prism sheets are arranged in a symmetrical configuration to reduce an unnatural motion parallax caused by optical aberrations. A cross-section of the 3D image is formed by the DCRA in midair and moved by the rotating prism sheets to create a 3D displayable space. A 3D volume image was displayed without image distortion or unnatural motion parallax.

Volumetric display using a rotating prism sheet as an optical image scanner.

We developed a volumetric display that uses a rotating prism sheet as an optical scanner. A cross-sectional image of a three-dimensional (3D) object was moved laterally by the rotating prism sheet. A stack of the cross-sectional images constructed a 3D volume image that satisfies all requirements of stereoscopic vision. Since the mechanical load of the proposed scanning method was small, it is easy to enlarge the effective area of the scanner and its scanning area. We used a concave mirror to collimate rays emitted from each point to reduce the aberration caused at the prism sheet. A displayed 3D image had a size of 7 cm × 5 cm × 7 cm and a resolution of 1024 × 768 × 200 voxels.

Floating volumetric image formation using a dihedral corner reflector array device.

A volumetric display system using an optical imaging device consisting of numerous dihedral corner reflectors placed perpendicular to the surface of a metal plate is proposed. Image formation by the dihedral corner reflector array (DCRA) is free from distortion and focal length. In the proposed volumetric display system, a two-dimensional real image is moved by a mirror scanner to scan a three-dimensional (3D) space. Cross-sectional images of a 3D object are displayed in accordance with the position of the image plane. A volumetric image is observed as a stack of the cross-sectional images. The use of the DCRA brings compact system configuration and volumetric real image generation with very low distortion. An experimental volumetric display system including a DCRA, a galvanometer mirror, and a digital micro-mirror device was constructed to verify the proposed method. A volumetric image consisting of 1024×768×400 voxels was formed by the experimental system.

Shape estimation of transparent objects by using inverse polarization ray tracing.

Few methods have been proposed to measure three-dimensional shapes of transparent objects such as those made of glass and acrylic. In this paper, we propose a novel method for estimating the surface shapes of transparent objects by analyzing the polarization state of the light. Existing methods do not fully consider the reflection, refraction, and transmission of the light occurring inside a transparent object. We employ a polarization raytracing method to compute both the path of the light and its polarization state. Polarization raytracing is a combination of conventional raytracing, which calculates the trajectory of light rays, and Mueller calculus, which calculates the polarization state of the light. First, we set an initial value of the shape of the transparent object. Then, by changing the shape, the method minimizes the difference between the input polarization data and the rendered polarization data calculated by polarization raytracing. Finally, after the iterative computation is converged, the shape of the object is obtained. We also evaluate the method by measuring some real transparent objects.

Volumetric display system based on three-dimensional scanning of inclined optical image.

A volumetric display system based on three-dimensional (3D) scanning of an inclined image is reported. An optical image of a two-dimensional (2D) display, which is a vector-scan display monitor placed obliquely in an optical imaging system, is moved laterally by a galvanometric mirror scanner. Inclined cross-sectional images of a 3D object are displayed on the 2D display in accordance with the position of the image plane to form a 3D image. Three-dimensional images formed by this display system satisfy all the criteria for stereoscopic vision because they are real images formed in a 3D space. Experimental results of volumetric imaging from computed-tomography images and 3D animated images are presented.

Fluorescent volumetric display excited by a single infrared beam.

A volumetric display technique that uses fluorescence excited by a single infrared beam is proposed. A convergent laser beam is used to activate ions locally around the focal point. Three-dimensional scanning by the focal point is achieved by moving an inclined image plane in the direction perpendicular to an optical axis. Preliminary experimental results of three-dimensional image generation in an Er(3+)-doped fluoride glass excited by a laser beam of 810 nm wavelength are presented.

Transparent surface modeling from a pair of polarization images.

We propose a method for measuring surface shapes of transparent objects by using a polarizing filter. Generally, the light reflected from an object is partially polarized. The degree of polarization depends upon the incident angle, which, in turn, depends upon the surface normal. Therefore, we can obtain surface normals of objects by observing the degree of polarization at each surface point. Unfortunately, the correspondence between the degree of polarization and the surface normal is not one to one. Hence, to obtain the correct surface normal, we have to solve the ambiguity problem. In this paper, we introduce a method to solve the ambiguity by comparing the polarization data in two objects, i.e., normal position and tilted with small angle position. We also discuss the geometrical features of the object surface and propose a method for matching two sets of polarization data at identical points on the object surface.