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In this paper, a new technique for controlling dc-dc resonant converters is investigated. A variable inductance is used to control and regulate the dc output voltage maintaining constant switching frequency for the half-bridge transistors. The output voltage characteristics of the series resonant and parallel resonant converters under the proposed magnetic control are obtained and analyzed. In order to evaluate the proposed technique, a laboratory prototype for a 48 V-input 5 V/10 A-output 500 kHz parallel resonant converter is presented. A methodology for obtaining the converter dynamic response using a step response test is carried out. From the dynamic response, a compensator for operating the converter at closed loop is developed and tested in the laboratory. The results prove that the proposed technique is suitable for controling resonant inverters at constant frequency using a low-cost half-bridge inverter. [ABSTRACT FROM AUTHOR]

Background: Surgical navigation in TKA facilitates better alignment; however, it is unclear whether improved alignment alters clinical evolution and midterm and long-term complication rates.Questions/purposes: We determined the alignment differences between patients with standard, manual, jig-based TKAs and patients with navigation-based TKAs, and whether any differences would modify function, implant survival, and/or complications.Patients and Materials: We retrospectively reviewed 97 patients (100 TKAs) undergoing TKAs for minimal preoperative deformities. Fifty TKAs were performed with an image-free surgical navigation system and the other 50 with a standard technique. We compared femoral angle (FA), tibial angle (TA), and femorotibial angle (FTA) and determined whether any differences altered clinical or functional scores, as measured by the Knee Society Score (KSS), or complications. Seventy-three patients (75 TKAs) had a minimum followup of 8 years (mean, 8.3 years; range, 8-9.1 years).Results: All patients included in the surgical navigation group had a FTA between 177° and 182º. We found no differences in the KSS or implant survival between the two groups and no differences in complication rates, although more complications occurred in the standard technique group (seven compared with two in the surgical navigation group).Conclusions: In the midterm, we found no difference in functional and clinical scores or implant survival between TKAs performed with and without the assistance of a navigation system.Level Of Evidence: Level II, therapeutic study. See the Guidelines online for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

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Background: Rotating-hinge total knee prostheses may be used for the treatment of global instability about the knee. The designs of previous generations were associated with suboptimal outcomes.Questions/purposes: We evaluated the clinical and radiographic outcomes of salvage knee reconstructions using modern-generation, modular, kinematic rotating-hinge total knee prostheses.Methods: We retrospectively reviewed 26 rotating-hinge arthroplasty devices to examine whether acceptable results were obtainable using a single arthroplasty design. The average age of the patients was 77 years (SD, 9 years); the minimum followup was 24 months (mean, 46 months; range, 24-107 months). The indication was revision surgery in 21 patients and complex primary surgery in five. Patients were evaluated clinically (Knee Society score) and radiographically (positions of components, signs of loosening, bone loss).Results: Knee Society pain scores improved from 40 preoperatively to 77 postoperatively, and function scores improved from 36 to 51. ROM improved from -15 masculine to -10 masculine. None of the patients' knee pain or function worsened. No loosening of implants was observed. Nonprogressive radiolucent lines were identified around the femoral and tibial components in three knees. Three patients required reoperations: one showed a supracondylar periprosthetic fracture treated by open reduction and internal fixation, whereas the other two had periprosthetic infections.Conclusions: Reconstruction with rotating-hinge total knee prostheses can provide substantial improvement in function and a reduction in pain in extreme circumstances, such as gross instability. We believe this salvage procedure should be reserved for severe ligamentous deficiencies in elderly and sedentary patients or whenever revision surgery techniques fail.Level Of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: The accuracy of computer navigation applied to total knee arthroplasty (TKA) in knees with severe deformity has not been studied.Questions/purposes: The purpose of this study was to compare the radiographic alignment achieved in total knee replacements performed with and without navigation and to search for differences in the final alignment of two groups of patients (with and without previous joint deformities) using the same system of surgical navigation.Methods: The first series comprised 40 arthroplasties with minimal preoperative deformity. In 20 of them, surgical navigation was used, whereas the other 20 were performed with conventional jig-based technique. We compared the femoral angle, tibial angle, and femorotibial angle (FTA) by performing a post-TKA CT of the entire limb. In the second series, 40 additional TKAs were studied; in this case, however, they presented preoperative deformities greater than 10 masculine in the frontal plane.Results: The positioning of the femoral and tibial component was more accurate in the group treated with surgical navigation and FTA improvement was statistically significant. When comparing the results of both series, FTA precision was always higher when using computer-assisted surgery. As for optimal FTA, data showed the use of surgical navigation improved the results both in the group with preoperative deformity greater than 10 degrees in the frontal plane and in the group with minimal preoperative knee deformity.Conclusions: Surgical navigation obtains better radiographic results in the positioning of the femoral and tibial components and in the final axis of the limb in arthroplasties performed on both deformed and more normally aligned knees.Level Of Evidence: Level II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Some studies have raised the question about whether the good results obtained with the Charnley prosthesis could be replicated at general hospitals when it comes to the frequency of early complications and failure rates, both of which would be higher than those published by centres devoted to hip arthroplasties.Methods: We reviewed the results of 404 Low Friction Arthroplasties of the hip implanted between 1976 and 1993 in a general hospital by general orthopaedic surgeons. For the survival analysis, the end-point chosen would be the chirurgical revision of any of the prosthetic components for whatever reason.Results: The complications were 16 dislocations (4%), 14 deep infections (3.5%), 2 neurological injuries (0,5%) and 5 clinical deep venous thromboses (1.2%) (2 pulmonary embolisms). The survival rate at 25 years, both for stem and cup, was 83%. Survival was higher in those arthroplasties implanted in patients older than 60 years, with statistical significance.Conclusion: Low Friction Arthroplasty undertaken at general hospitals by general orthopaedic surgeons feature similar outcomes to those found in centres devoted to hip surgery. [ABSTRACT FROM AUTHOR]

Introduction: The number of chronic total occlusion (CTO) revascularization procedures has continuously increased, obtaining better results in recent years. However, there are few data regarding long-term outcomes and no comparisons to planned complex non-CTO percutaneous coronary intervention (PCI). Methods: We included all patients undergoing planned complex PCI. Our main objective was to compare a combined endpoint of all-cause death, myocardial infarction, and target vessel revascularization at the long-term follow-up of CTO PCI versus planned complex non-CTO PCI. We compared the groups using multivariable Cox regression and performed a propensity score matching analysis to control the baseline characteristics. We repeated the analysis for the separate components of the primary endpoint. Results: From January 2018 to June 2023, 1394 complex coronary PCIs were performed at our center. After excluding 393 non-planned cases, 201 CTO PCIs and 800 non-CTO PCIs were included. The mean follow-up was 2.5 ± 1.5 years. The composite endpoint occurred in 23 (11.6%) CTO PCIs and 219 (28.2%) planned non-CTO PCIs. The multivariable Cox regression using the CTO group as the reference showed a lower risk for the primary outcome (HR: 0.59; 95% CI 0.37-0.95; p = 0.031). After matching, a total of 195 adequately balanced pairs were obtained. The CTO group presented a lower risk for the primary combined outcome (HR: 0.46; 95% CI 0.27-0.76; p = 0.003). Conclusions: In patients undergoing planned complex PCI, those in the CTO group presented a reduced risk of all-cause death, myocardial infarction, and target vessel revascularization at the end of the follow-up.

Introduction: Complex Percutaneous coronary intervention (PCI) for the treatment of ischemic heart disease has increased significantly. We aimed to evaluate sex-related differences in patients undergoing complex PCI., Methods: single-center prospective observational study including patients undergoing complex PCI between 2017 and 2023. Baseline and procedural features, and mid-term outcomes were compared according to the gender distribution. The combined primary endpoint included stroke, myocardial infarction, need for a new coronary revascularization, and all-cause mortality. Propensity score (PS) matching with an inverse probability of treatment weight (IPW) approach was used to adjust for differences in baseline characteristics., Results: 1,283 patients were included, 983 (76.6%) male and 300 (23.4%) female. Median follow-up was 2.4 (IQR: 1-3.8) years. There was a higher rate of no-reflow phenomenon (4% vs. 1.8%, p  = 0.03) among female patients. In the overall cohort, female patients had a greater risk for the combined primary endpoint (HR 1.28, 95% CI: 1.02-1.59). In the matched cohort, female patients exhibited a higher risk for the combined primary endpoint (HR 1.23, 95% CI: 1.06-1.42), as well as for myocardial infarction (HR 1.34, 95% CI 1.03-1.75), and all-cause mortality (HR 1.21, 95% CI 1.02-1.45), and a trend towards a higher risk for the need of a new coronary revascularization (HR 1.22, 95% CI 0.92-1.61)., Conclusions: in a contemporary cohort of patients undergoing complex PCI procedures, female patients are associated with a higher risk of early complications., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Alperi, Almendárez, Pascual, Alvarez, Betanzos, Hernández-Vaquero, Ptaszynski, Ortiz, Moris and Avanzas.)

Navigation in total knee arthroplasties has been recommended in recent years to facilitate the technique and improve its results. An extensive literature has compared it with conventional surgery, but its superiority has not been able to be demonstrated. Given the abundant bibliography and disparity in their conclusions, a good number of meta-analyses have been published that have attempted to summarize and schematize the results. We have reviewed 41 published meta-analyses comparing both techniques. Most of them have focused on the placement of implants and the restoration of the axes of the extremity, demonstrating the superiority of navigation. On the contrary, no clinically valuable differences have been observed when analyzing the clinical and functional results. However, navigation allows a dynamic view of the knee, an objective evaluation of the soft tissues and ligaments, and is essential for functional alignment as an individualized technique.

Background/Objectives : Understanding sex-based differences in cardiovascular outcomes is paramount to improving clinical outcomes. Surgery is an aggressive but effective therapy for ascending aortic aneurysm. We sought to determine if being a woman is a risk factor for long-term mortality after this surgery. We compared their life expectancy with a general population of the same age, sex, year, and region. Methods : We compared men and women undergoing AAA surgery at our institution from 2000 to 2019. After balancing the population with propensity score (PS) matching, we compared long-term mortality control with a Cox regression. We determined the RS using the Ederer II method and compared it to a healthy reference population of the same age, sex, and region. Results : From 2000 to 2019, 232 women and 506 men underwent ascending aortic aneurysm surgery. After a mean follow-up of 51.5 ± 34.5 months, sex was not an independent risk factor for long-term mortality in the multivariable analysis [HR: 0.68 (95% CI 0.43-1.07, p = 0.23)]. Matching by baseline characteristics, 196 pairs were analyzed with no differences regarding mortality in the Cox regression [HR: 1.11 (95% CI 0.65-1.9, p = 0.23)]. Men and women who survived the postoperative period presented a relative survival of 100.3% (95% CI 97.4-101%) and 100.3% (95% CI 98.9-101.1%), respectively, similar to the reference population without the disease. Conclusions : For patients undergoing AAA surgery, sex was not an independent predictor of mortality. Men and women who survived the postoperative period presented a similar life expectancy to that of the reference population (people free from the disease of the same age, sex, year, and region).

Objectives: Little is known about valve hemodynamic performance during the Evolut and Neo deployment course. We aimed to evaluate transvalvular mean and peak-to-peak gradients over several intraprocedural timepoints during TAVR with Evolut PRO+ (Medtronic) and Neo (Boston Scientific) systems., Methods: This was single-center pilot sub-study from the SavvyWire EFficacy and SafEty in Transcatheter Aortic Valve Implantation Procedures (SAFE-TAVI) trial. Participants received either the Evolut PRO+ or Neo for native valve severe aortic stenosis and the SavvyWire (OpSens Medical) was used for device delivery, pacing, and continuous left ventricular and aortic pressure measurements. For the Evolut, evaluation was done for baseline, two-thirds of valve deployment (still recapturable), 90% of valve deployment (no longer recapturable), and post-deployment hemodynamics. For the Neo, analysis was done at baseline, after the first step (top-crown deployment), and at final status., Results: Nineteen patients were included (Evolut = 15; Neo = 4). There were no statistically significant changes in peak-to-peak gradients (44 mm Hg [IQR:33-69] vs 43 mm Hg [IQR:26-62], P = .41) between baseline and two-thirds of valve deployment in the Evolut patients. There was a significant decrease in mean (40 mm Hg [IQR:32-54] vs 14 mm Hg [IQR:10-18], P less than .001) and peak-to-peak (43 mmHg [IQRS:26-62] vs 9 mm Hg [IQR:8-13], P less than .001) transvalvular gradients between two-thirds and 90% of valve deployment for Evolut. Neo patients exhibited a decrease in transvalvular gradients after top-crown deployment (42.5 mm Hg baseline vs 13 mm Hg)., Conclusions: Transvalvular gradients did not vary between the point of "no-recapture" compared to baseline values in patients receiving the Evolut, whereas a significant reduction in transvalvular gradients was observed when the valve was deployed at 90% and fully deployed. The Neo valve was slightly obstructive after the first step of deployment.

Objectives: Recently, desert dust in Europe has been recognized as a cardiovascular health problem. In Spain, desert dust inflows in recent years have been associated with worsening air quality. The present study examines whether desert dust events are related to the incidence of acute coronary syndrome (ACS) in patients under 55 years of age. Methods: Data from 2416 consecutive patients admitted to a tertiary hospital due to ACS were prospectively analyzed. A case-crossover time-stratified design using Poisson conditional regression models was applied to estimate the impact of desert dust events involving particulate matter concentrations of an aerodynamic diameter <10 μm (PM 10 ) on the incidence of ACS in patients under 55 years of age. Results: Desert dust intrusion on days 0 to 5 before ACS onset showed no significant association with the incidence of ACS in patients under 55 years of age. The incidence rate ratios of PM 10 concentrations 1, 2, 3, 3, 4, and 5 days before ACS onset (for changes of 10 µg/m 3 ) were 1.02 (95% CI 0.97-1.1; p = 0.41), 1.01 (95% CI 0.96-1.07; p = 0.66), 0.99 (95% CI 0.94-1.05; p = 0.78), 0.96 (95% CI 0.9-1.02; p = 0.18), and 0.97 (95% CI 0.91-1.04; p = 0.41). Conclusions: Our findings suggest that desert dust is unlikely to be related to the incidence of ACS in patients under 55 years of age.

Background Technologies such as navigation and robotics are aimed at improving tibial alignment in total knee arthroplasties (TKA) and eliminating the errors resulting from the use of manual instrumentation. Methods This prospective study analyzed 130 arthroplasties in order to determine whether navigation can improve the frontal mechanical axis of the tibia and whether the postoperative angulation of this axis differs from the preoperative one. The mean patient age was 71.8 years, and the mean BMI was 31.17. Eighty-six patients were female. The same cemented TKA model and the same imageless navigation system were used in all cases. Results The mean postoperative tibial angle following implantation was 87.65°, without any statistically significant differences with respect to the previous angulation. However, navigation was seen to result in a nearly neutral tibial axis, a larger number of cases (41.5%-60.8% {p = 0.002}) aligned within the safe zone (90° ± 3°), a smaller number of outliers, and a clustering of values around the mean. Conclusions Navigation improves the frontal positioning of the tibial component in total knee arthroplasties but does not offer any advantages as compared with conventional instrumentation., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Hernandez-Vaquero et al.)

Aims: The main objective of this study is to determine whether exposure to Saharan dust causes airway inflammation and oxidative stress in patients with stable chronic heart failure (HF) and a left ventricular ejection fraction of less than 40%., Methods: A longitudinal study design is used, involving the inclusion of 40 patients with stable chronic HF and a left ventricular ejection fraction of less than 40%. Four sputum samplings will be taken from each patient, with one sampling taken each week over four consecutive weeks. The sputum samples will be used to analyze the degree of inflammation and oxidative stress. Air quality monitoring stations will be used to analyze the particulate matter (PM) exposure of each patient. The intrusion of desert dust will be identified using meteorological models. There will be 160 scheduled samplings in 40 patients with chronic HF. Mixed regression models will be used to assess the influence of the concentrations of PM (from the episodes of desert dust) upon the airway inflammation and oxidative stress markers., Conclusion: The results of this study will test the hypothesis that exposure to high concentrations of Saharan dust affects the normal function of the respiratory epithelium due to the imbalance between the production of free radicals and antioxidant enzymes, thus causing increased pulmonary inflammation and oxidative stress in patients with HF that in turn may facilitate decompensations of their background disease condition.

Introduction: Mitral Regurgitation (MR) has a strong impact on quality of life and on mid-term survival. Transcatheter mitral valve replacement (TMVR) is rapidly expanding and a growing number of studies have been published recently., Methods: A systematic review of studies reporting on clinical data for patients with symptomatic severe MR undergoing TMVR was performed. Early- and mid-term outcomes (clinical and echocardiographic) were evaluated. Overall weighted means and rates were calculated. Risk ratios or mean differences were calculated for pre- and post-procedural comparisons., Results: A total of 12 studies and 347 patients who underwent TMVR with devices clinically available or under clinical evaluation were included. Thirty-day mortality, stroke and major bleeding rates were 8.4%, 2.6%, and 15.6%, respectively. Pooled random-effects demonstrated a significant reduction of ≥ grade 3+ MR (RR: 0.05; 95% CI: 0.02-0.11; p  < 0.001) and in the rates of patients in NYHA class 3-4 after the intervention (RR: 0.27; 95% CI: 0.22-0.34; p  < 0.001). Additionally, the pooled fixed-effect mean difference for quality of life based on the KCCQ score yielded an improvement in 12.9 points (95% CI:7.4-18.4, p  < 0.001), and exercise capacity improved by a pooled fixed-effect mean difference of 56.8 meters in the 6-minute walk test (95% CI 32.2-81.3, p  < 0.001)., Conclusions: Among 12 studies and 347 patients comprising the updated evidence with current TMVR systems there was a statistically significant reduction in ≥ grade 3+ MR and in the number of patients exhibiting poor functional class (NYHA 3 or 4) after the intervention. Overall rate of major bleeding was the main shortcoming of this technique., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Alperi, Avanzas, Leon, Silva, Hernández-Vaquero, Almendárez, Álvarez, Fernández, Moris and Pascual.)

Background: The use of mitral transcatheter edge-to-edge repair (TEER) is rapidly increasing. Anatomical changes have been described after TEER with the MitraClip system in patients with functional mitral regurgitation (MR), although no study has yet evaluated such anatomical impacts in patients treated with the G4 MitraClip generation., Methods: This research constituted a prospective, single-center, observational study including consecutive patients with functional MR. Mitral three-dimensional images were obtained transesophageally with echocardiography before and immediately after TEER. Patients receiving the late-generation (G4) system were compared to those receiving early-generation systems., Results: A total of 116 functional MR patients were evaluated, and 40 (34.5%) and 76 (65.5%) received a late-generation (G4) or early-generation device system, respectively. The baseline clinical and echocardiographic features were well-balanced between the groups. Overall, there was a significant reduction in mitral annular size after the intervention, and greater reductions in the anteroposterior diameter (4 mm vs. 3.54 mm, p = 0.03), annular perimeter (11.07 mm vs. 5.29 mm for 3D-perimeter, p = 0.001), and annular area (1.29 cm 2 vs. 1.03 cm 2 , p = 0.002) were found for patients receiving the late G4 device generation compared to the early-generation systems., Conclusions: In patients with functional MR, we observed significant changes in mitral valve anatomy with a reduction in anteroposterior diameter, valve perimeter, and area. In our cohort, the extent of those changes was greater with the use of the new-generation G4 MitraClip system compared to prior device generations.