Effects of mitral valve disease etiology on the outcomes of mechanical and biological valve replacement: retrospective cohort study.

INTRODUCTION: The choice of an artificial mitral valve (MV) is a crucial clinical decision that affects the long-term survival and quality of life of patients. However, current guidelines recommend selecting MV based on patient age and life expectancy at the time of MV replacement (MVR), without considering the etiology of MV disease. This study aimed to investigate whether MV disease etiology should be considered when choosing a valve for MVR and to evaluate the impact of MV disease etiology on long-term patient survival. METHODS: Using data (2002 to 2018) from Taiwan's National Health Insurance Research Database, we conducted a nationwide retrospective cohort study to compare the biological and mechanical valves in terms of all-cause mortality as the primary outcome. The inverse probability of the treatment weighting method was used to reduce the effects of the confounding factors. The following etiologies were assessed: infective endocarditis (IE), rheumatic heart disease (RHD), ischemic mitral regurgitation (IMR), and degenerative mitral regurgitation (DMR). RESULTS: In patients aged <70 years, it was observed that mechanical valves demonstrated an association with benefits compared to biological valves in the context of survival. In patients with IE aged <72 years, mechanical valves were associated with survival benefits, but not in those with stroke during hospitalization. These valves were also found to be linked with survival advantages for patients with RHD aged <60 years and for those with DMR aged < 72 years. However, no age-dependent effects of valve type on all-cause mortality were observed in patients with IMR. CONCLUSION: The etiology of MV disease appears to be important in the selection of a suitable MV and determination of a cutoff age for mechanical and biological MVR.

Sex Differences in Epidemiological Distribution and Outcomes of Surgical Mitral Valve Disease.

BACKGROUND: Mitral valve (MV) disease is the most common form of valvular heart disease. Findings that indicate women have a higher risk for unfavorable outcomes than men remain controversial. This study aimed to determine the sex-based differences in epidemiological distributions and outcomes of surgery for MV disease.Methods and Results: Overall, 18,572 patients (45.3% women) who underwent MV surgery between 2001 and 2018 were included. Outcomes included in-hospital death and all-cause mortality during follow up. Subgroup analysis was conducted across different etiologies, including infective endocarditis (IE), degenerative, ischemic, and rheumatic mitral pathology. The overall MV repair rate was lower in women than in men (20.5% vs. 30.6%). After matching, 6,362 pairs (woman : man=1 : 1) of patients were analyzed. Women had a slightly higher risk for in-hospital death than men (10.8% vs. 9.8%; odds ratio [OR]: 1.11, 95% confidence interval [CI]: 0.99-1.24; P=0.075). Women tended to have a higher incidence of de novo dialysis (9.8% vs. 8.6%; P=0.022) and longer intensive care unit stay (8 days vs. 7.1 days; P<0.001). Women with IE had poorer in-hospital outcomes than men; however, there were no sex differences in terms of all-cause mortality. CONCLUSIONS: Sex-based differences of MV intervention still persist. Although long-term outcomes were comparable between sexes, women, especially those with IE, had worse perioperative outcomes than men.

Mitral Valve Repair vs. Replacement by Different Etiologies　- A Nationwide Population-Based Cohort Study.

BACKGROUND: When mitral valve (MV) surgery is indicated, repair is preferred over replacement; however, this preference is not supported by evidence from clinical trials. Furthermore, the benefits of MV repair may not be universal for all etiologies of MV disease.Methods and Results: This study identified a total of 18,428 patients who underwent MV repair (n=4,817) or MV replacement (n=13,611) during 2001-2018 from Taiwan's National Health Insurance Research Database. These patients were classified into 4 etiologies: infective endocarditis (IE, n=2,678), rheumatic heart disease (RHD, n=4,524), ischemic mitral regurgitation (IMR, n=3,893), and degenerative mitral regurgitation (DMR, n=7,333). After propensity matching, all-cause mortality during follow-up was lower among patients receiving MV repair than among patients receiving MV replacement in the IE, IMR, and DMR groups (hazard ratio [HR]=0.72, 95% confidence interval [CI]: 0.55-0.93; HR=0.82, 95% CI: 0.73-0.92; and HR 0.73, 95% CI: 0.64-0.84, respectively). However, in the RHD group, the MV reoperation rate was higher after MV repair than after MV replacement (subdistribution HR=1.91, 95% CI: 1.02-3.55). CONCLUSIONS: In comparison with MV replacement, MV repair was associated with a lower late mortality in patients with IE, IMR, and DMR, and a higher risk of reoperation in patients with RHD.

Mechanical Versus Bioprosthetic Aortic Valve Replacement in Patients Undergoing Bentall Procedure.

BACKGROUND: The widely used Bentall procedure is the criterion standard treatment for aortic root pathology. Studies comparing the long-term outcomes of bioprosthetic and mechanical valves in patients undergoing the Bentall procedure are limited. METHODS AND RESULTS: Patients who underwent the Bentall procedure with a bioprosthetic or mechanical valve between 2001 and 2018 were identified from Taiwan's National Health Insurance Research Database. The primary outcome of interest was all-cause mortality. Inverse probability of treatment weighting was performed to compare the 2 prosthetic types. In total, 1052 patients who underwent the Bentall procedure were identified. Among these patients, 351 (33.4%) and 701 (66.6%) chose bioprosthetic and mechanical valves, respectively. After inverse probability of treatment weighting, no significant differences in the in-hospital mortality (odds ratio, 0.96 [95% CI, 0.77-1.19]; P=0.716) and all-cause mortality (34.1% vs. 38.1%; hazard ratio, 0.90 [95% CI, 0.78-1.04]; P=0.154) were observed between the groups. The benefits of relative mortality associated with mechanical valves were apparent in younger patients and persisted until ≈50 years of age. CONCLUSIONS: No differences in survival benefits were observed between the valves in patients who underwent the Bentall procedure. Additionally, bioprosthetic valves may be a reasonable choice for patients aged >50 years when receiving the Bentall procedure in this valve-in-valve era.

Sex differences in utilisation of extracorporeal membrane oxygenation support and outcomes in Taiwan.

BACKGROUND: The impact of sex-related differences in patients receiving extracorporeal membrane oxygenation support (ECMO) support is still inconclusive. This population-based study aimed to investigate sex differences in short- or long-term outcomes in order to improve clinical practice. METHODS: Patients who received ECMO between 2001 to 2017 were identified from the Taiwan National Health Insurance Research Database. Propensity score matching with a 1:1 ratio was conducted in female-to-male groups, to reduce confounding of baseline covariates. Outcomes included in-hospital mortality, all-cause mortality, all-cause readmission, and ECMO-related complications. Logistic regression analysis, Cox proportional hazard model, and join point regression were used to compare sex differences in both short- or long-term outcomes. RESULTS: In total, 7,010 matched patients from 11,734 ECMO receivers were included for analysis. The use of ECMO increased dramatically in past years, although the proportion of females was still lower than males. There was a decreasing trend of females undergoing ECMO over time. Female patients have lower risks of in-hospital mortality (64.08% in females vs 66.48% in males; P = 0.0352) and ECMO-related complications compared with males. Furthermore, females also had favorable long-term late outcomes such as all-cause mortality (73.35% in females vs 76.98% in males; P = 0.009) and readmission rate (6.99% in females vs 9.19% in males; P = 0.001). CONCLUSIONS: Female patients had more favorable in-hospital and long-term survival outcomes. Despite improvement in modern ECMO technique and equipment, ECMO remains underutilized in eligible female patients. Thus, females should undergo ECMO treatment if available and indicated. TRIAL REGISTRATION: The institutional review board of Chang Gung Memorial Hospital approved all data usage and the study protocol (registration number: 202100151B0C502; date of registration: 23/08/2021).

Surgical volume and outcomes of surgical ablation for atrial fibrillation: a nationwide population-based cohort study.

BACKGROUND: Atrial fibrillation is the most common cardiac arrythmia and causes many complications. Sinus rhythm restoration could reduce late mortality of atrial fibrillation patients. The Maze procedure is the gold standard for surgical ablation of atrial fibrillation. Higher surgical volume has been documented with favorable outcomes of various cardiac procedures such as mitral valve surgery and aortic valve replacement. We aimed to determine the volume-outcome relationship (i.e., association between surgical volume and outcomes) for the concomitant Maze procedure during major cardiac surgeries. METHODS: This nationwide population-based cohort study retrieved data from the Taiwan National Health Insurance Research Database. Adult patients undergoing concomitant Maze procedures during 2010-2017 were identified; consequently, 2666 patients were classified into four subgroups based on hospital cumulative surgery volumes. In-hospital outcomes and late outcomes during follow-up were analyzed. Logistic regression and Cox proportional hazards model were used to analyze the volume-outcome relationship. RESULTS: Patients undergoing Maze procedures at lower-volume hospitals tended to be frailer and had higher comorbidity scores. Patients in the highest-volume hospitals had a lower risk of in-hospital mortality than those in the lowest-volume hospitals [adjusted odds ratio, 0.30; 95% confidence interval (CI), 0.15-0.61; P < 0.001]. Patients in the highest-volume hospitals had lower rates of late mortality than those in the lowest-volume hospitals, including all-cause mortality [adjusted hazard ratio (aHR) 0.53; 95% CI 0.40-0.68; P < 0.001] and all-cause mortality after discharge (aHR 0.60; 95% CI 0.44-0.80; P < 0.001). CONCLUSIONS: A positive hospital volume-outcome relationship for concomitant Maze procedures was demonstrated for in-hospital and late follow-up mortality. The consequence may be attributed to physician skill/experience, experienced multidisciplinary teams, and comprehensive care processes. We suggest referring patients with frailty or those requiring complicated cardiac surgeries to high-volume hospitals to improve clinical outcomes. TRIAL REGISTRATION: the institutional review board of Chang Gung Memorial Hospital approved all data usage and the study protocol (registration number: 202100151B0C502).

Sex differences in risks of in-hospital and late outcomes after cardiac surgery: a nationwide population-based cohort study.

OBJECTIVES: Outcomes of sex differences in major cardiac surgery remain controversial. A comprehensive understanding of sex differences in major adult cardiac surgery could provide better knowledge of risk factors, management strategy and short-term or long-term outcomes. The present study aimed to investigate sex differences in the risks of outcomes of major cardiac surgeries and subgroup analyses of different valve types. DESIGN: Population-based nationwide cohort study. SETTING: Data were obtained from National Health Insurance Research Database (NHIRD) in Taiwan. PARTICIPANTS: A total of 66 326 adult patients (age ≥20 years; 30.3% women) who underwent a first major cardiac surgery (isolated coronary artery bypass graft (CABG), isolated valve or concomitant bypass/valve) from 2000 to 2013 were identified via Taiwan NHIRD. MAIN OUTCOME MEASURES: Outcomes of primary interest were in-hospital death and all-cause mortality during follow-up period. Propensity score matching was conducted as a secondary analysis for the sensitivity test. RESULTS: Women who underwent isolated CABG tended to have greater risks of both in-hospital (OR 1.37; 95% CI 1.26 to 1.49) and late outcomes (HR 1.26; 95% CI 1.22 to 1.31). Women after concomitant CABG/valve also had a greater in-hospital (OR 1.19; 95% CI 1.01 to 1.40) and long-term mortality (HR 1.14; 95% CI 1.05 to 1.24). Women after isolated mitral valve repair have a non-favourable outcome of in-hospital mortality (OR 1.70; 95% CI 1.01 to 2.87). Women who did not receive an isolated aortic valve replacement had more favourable all-cause mortality outcome (HR 0.90; 95% CI 0.84 to 0.96). Secondary analysis in the propensity score-matching cohort demonstrated results similar to the primary analysis. CONCLUSIONS: Female patients who underwent procedures involving CABG (with or without concurrent valvular intervention) had generally worse outcomes. However, the results of isolated valve surgery were variable on the basis of the type of intervened valve.

Cu(II) and Au(III) recovery with electrospun lignosulfonate CO2-activated carbon fiber.

The objectives of this study were twofold: developing lignosulfonate activated carbon fibers (LACFs) and determining the corresponding metal recovery mechanisms with batch experiments and non-linear modeling. LACFs were developed through electrospinning, followed by CO2-based physical activation. Physical and chemical characterizations revealed that the LACF sample that was activated for 60 min exhibited a higher specific surface area (376.54 m2/g), larger total pore volume (0.30 cm3/g), higher micropore ratio (32%), and more acidic and sulfur functional groups than did the other samples. Cu(II) and Au(III) adsorption behaviors on the LACF could be described with the Freundlich and Langmuir model, respectively. Both systems consist of physisorption and chemisorption, and the mechanisms include electrostatic forces, Van der Walls forces, cation exchange, surface complexation. In particular, Au(III) adsorption was faster, and LACF-Au bonds were stronger due to the additional microprecipitation. Furthermore, the LACF sample could regenerate after three adsorption-desorption cycles. Overall, this study provides the foundation for developing physically activated lignosulfonate carbon and its application in recovering valuable metal ions.

3D Printing of Collagen/Oligomeric Proanthocyanidin/Oxidized Hyaluronic Acid Composite Scaffolds for Articular Cartilage Repair.

Articular cartilage defects affect millions of people worldwide, including children, adolescents, and adults. Progressive wear and tear of articular cartilage can lead to progressive tissue loss, further exposing the bony ends and leaving them unprotected, which may ultimately cause osteoarthritis (degenerative joint disease). Unlike other self-repairing tissues, cartilage has a low regenerative capacity; once injured, the cartilage is much more difficult to heal. Consequently, developing methods to repair this defect remains a challenge in clinical practice. In recent years, tissue engineering applications have employed the use of three-dimensional (3D) porous scaffolds for growing cells to regenerate damaged cartilage. However, these scaffolds are mainly chemically synthesized polymers or are crosslinked using organic solvents. Utilizing 3D printing technologies to prepare biodegradable natural composite scaffolds could replace chemically synthesized polymers with more natural polymers or low-toxicity crosslinkers. In this study, collagen/oligomeric proanthocyanidin/oxidized hyaluronic acid composite scaffolds showing high biocompatibility and excellent mechanical properties were prepared. The compressive strengths of the scaffolds were between 0.25-0.55 MPa. Cell viability of the 3D scaffolds reached up to 90%, which indicates that they are favorable surfaces for the deposition of apatite. An in vivo test was performed using the Sprague Dawley (SD) rat skull model. Histological images revealed signs of angiogenesis and new bone formation. Therefore, 3D collagen-based scaffolds can be used as potential candidates for articular cartilage repair.

Increased FIO2 influences SvO2 interpretation and accuracy of Fick-based cardiac output assessment in cardiac surgery patients: A prospective randomized study.

INTRODUCTION: The study aimed to reveal how the fraction of inspired oxygen (FIO2) affected the value of mixed venous oxygen saturation (SvO2) and the accuracy of Fick-equation-based cardiac output (Fick-CO). METHODS: Forty two adult patients who underwent elective cardiac surgery were enrolled and randomly divided into 2 groups: FIO2 < 0.7 or >0.85. Under stable general anesthesia, thermodilution-derived cardiac output (TD-CO), SvO2, venous partial pressure of oxygen, hemoglobin, arterial oxygen saturation, arterial partial pressure of oxygen, and blood pH levels were recorded before surgical incision. RESULTS: Significant differences in FIO2 values were observed between the 2 groups (0.56 ±â€Š0.08 in the <70% group and 0.92 ±â€Š0.03 in the >0.85 group; P < .001). The increasing FIO2 values lead to increases in SvO2, venous partial pressure of oxygen, and arterial partial pressure of oxygen, with little effects on cardiac output and hemoglobin levels. When comparing to TD-CO, the calculated Fick-CO in both groups had moderate Pearson correlations and similar linear regression results. Although the FIO2 <0.7 group presented a less mean bias and a smaller limits of agreement, neither group met the percentage error criteria of <30% in Bland-Altman analysis. CONCLUSION: Increased FIO2 may influence the interpretation of SvO2 and the exacerbation of Fick-CO estimation, which could affect clinical management. TRIAL REGISTRATION: ClinicalTrials.gov ID number: NCT04265924, retrospectively registered (Date of registration: February 9, 2020).

Fracture Characteristics and Energy Dissipation of Textile Bamboo Fiber Reinforced Polymer.

The fracture theory of fiber-reinforced polymer (FRP) composites is complicated compared to that of homogeneous materials. Textile FRPs need to consider crimp, fiber off-axis and various weaving parameters in a two-dimensional scale, which makes research of failure and fracture difficult. The objective and main contribution of the present research lie in taking textile bamboo FRP as an example and using tools such as toughness, load and deflection curves analysis, energy analysis, and first-order derivative signals to establish the preliminary information needed for fracture theory. This is followed by observing the fracture characteristics of the material under bending. The identification of fracture modes, corresponding energy, and energy dissipation are all prerequisites for developing fracture models in the future. Differences in the direction of force, weaving method, and number of laminates will cause the amount and direction of fibers to vary, which makes the type and progression of fracture different. Combining signal analysis, fracture images and energy dissipation curves, there are different modes of fracture between various groups due to different energy storage forms and crack types, which ultimately lead to different energy dissipation behaviors.

Cellulose Nanocrystal Isolation from Hardwood Pulp using Various Hydrolysis Conditions.

To expand the application field of the pulping industry, this study conducted a series of sample preparations for processing cellulose nanocrystals (CNCs) from a dry hardwood pulp to achieve optimal sulfuric acid hydrolysis. The properties of laboratory-prepared pulp CNCs (P-CNCs) were investigated with different preparation conditions including sulfuric acid concentrations, hydrolysis temperatures, and hydrolysis durations. Results showed a gradient of color changes observed with the increase of hydrolysis duration and temperature. Under certain conditions, the derived P-CNCs exhibited nanoscale dimensions, detected by transmission electron microscopy, and a crystallinity index similar to commercial products. In addition, the surface sulfate groups were assumed to be contributed by sulfuric acid hydrolysis. However, a high acid concentration and long hydrolysis processing duration introduced more sulfate groups on the derived P-CNCs, which may have acted as flame retardants and, thus, increased the amount of char residue.

Validity of accuracy and trending ability of non-invasive continuous total hemoglobin measurement in complex spine surgery: a prospective cohort study.

BACKGROUND: Patients undergoing complex spine surgery present with multilevel spinal involvement, advanced age, and multiple comorbidities. Surgery is associated with significant blood loss and remarkable hemodynamic changes. The present study aimed to investigate the accuracy and trending ability of a non-invasive continuous method to monitor hemoglobin (SpHb) concentrations using a Radical-7™ Pulse CO-Oximeter in complex spine surgery. METHODS: Forty-nine patients who underwent complex spine surgery were enrolled in this prospective observational study. Multiple time points were established for data collection throughout the operation. Simultaneous SpHb-total hemoglobin (tHb) paired data were recorded for analyses. Linear regression analysis, Bland-Altman plot, four-quadrant plot, and Critchley polar plot were used to assess the accuracy and trending ability of the monitor. RESULTS: A total of 272 pairs of SpHb-tHb data were available and were divided into two groups based on the perfusion index (PI): PI values ≥1.0 (n = 200) and PI values < 1.0 (n = 72). The correction coefficients (r) between SpHb and tHb were 0.6946 and 0.6861 in the groups with PI values ≥1.0 and < 1.0, respectively (P < 0000.1). In the ≥1.0 group, the mean bias was - 0.21 g/dL and the percentage error (PE) was 15.85%, whereas in the < 1.0 group, the mean bias was - 0.04 g/dL and the PE was 17.42%. Four-quadrant plot revealed a concordance rate of 85.11%, whereas the Critchley polar plot showed a concordance rate of 67.21%. CONCLUSIONS: The present study demonstrates the acceptable accuracy of the Radical-7™ Pulse CO-Oximeter even with a low PI. However, the trending ability was limited and unsatisfactory.

An analysis on the electrophoretic mobility of cellulose nanocrystals as thin cylinders: relaxation and end effect.

Cellulose nanocrystals (CNCs) are extracted from cellulosic fibers via sulfuric acid hydrolysis and found to exhibit unique properties due to their nanoscale, ordered structure, and surface morphology. The dispersion stability of a CNC suspension is a significant factor when CNCs are applied for reinforcement of a composite or ink jet printing. Since sulfuric acid hydrolysis introduces sulfate groups on CNC surfaces, we considered that charging conditions needed to be characterized, typically based on electrophoretic mobility. After the electrophoretic mobility was measured, several theoretical equations were applied to fit those values to assume the proper CNC particle shape. While Smoluchowski's equation is often used for this purpose, its applicability to CNCs should be reconsidered due to the thin, rod-like shape of CNCs with a finite length and high charge density. In this sense, we measured the surface charge and electrophoretic mobility of well-characterized CNCs. The obtained experimental data have been analyzed by using various electrokinetic equations. Our analytical results suggested that Smoluchowski's equation and the Ohshima-Henry equation overestimated the magnitude of the mobility of CNCs because it ignores the double layer relaxation and end effect. They also suggested that neither the Ohshima-Overbeek averaged equation nor the Ohshima-Overbeek perpendicular equation described the mobility of CNCs appropriately because those equations consider the double layer relaxation and end effect of a cylinder in a limited manner. Instead, the modified Ohshima-Overbeek equation was presented to be preferred for such a charged cylinder with a small aspect ratio.

Developing Lignosulfonate-Based Activated Carbon Fibers.

In this study, electrospinning technology, physical activation, and carbonization processing were applied to produce lignosulfonate-based activated carbon fibers. The porous structure of the produced lignosulfonate-based activated carbon fibers primarily contained mesopores and a relatively small amount of micropores. Moreover, insufficient carbonization caused fiber damage during CO2 activation. The weight loss rate and specific surface area increased with increase in carbonization time, and products with carbonization temperatures of 700 °C were of higher quality than those with other temperatures. Moreover, the two-step carbonization process provided fibers with improved quality because of a low weight loss rate, improved processing, and high surface area. Lignosulfonate-based activated carbon fibers can be used as a highly efficient adsorption and filtration material, and further development of its applications would be valuable.

Mechanical characterization of a single gold nanowire.

Mechanical properties of gold nanowires were individually determined in this investigation using a multifunctional nanomanipulator inside a scanning electron microscope (SEM). Gold nanowires were synthesized by an electrochemical deposition technique. Three different characterization techniques including tensile, buckling and bending tests were adapted to quantitatively determine Young's modulus, yield stress and failure stress of the gold nanowires. The mechanical characterizations show that the nanowires were highly flexible in nature. The excellent resilience and the ability to store elastic energy in these nanowires confirm their potential applications in nano electromechanical devices.