Effects of cardiac rehabilitation in patients with ventricular assist devices: a scoping review.

INTRODUCTION: Ventricular assist devices represent a treatment option for patients with advanced heart failure, offering control over various haemodynamic variables. Similarly, the prescription of exercise within a cardiac rehabilitation programme for heart failure patients is recommended to reduce symptoms, and hospitalisations, improve cardiorespiratory fitness, and increase exercise tolerance. Therefore, exercise prescription can impact those with ventricular assist devices. Given the limited evidence on exercise-based cardiac rehabilitation programmes for this population, this review aims to describe the most commonly used strategies and their health benefits when physical exercise is included in a cardiac rehabilitation programme for patients with ventricular assist devices. MATERIALS AND METHODS: An exploratory review was conducted through searches in the databases: PubMed, SCOPUS, PeDro, and ScienceDirect. The search was limited to studies published between 2013 and 2023. Filters were applied independently by title, abstract, and full text. The included articles were analysed based on the description of the types of cardiac rehabilitation strategies used in patients with ventricular assist devices. RESULTS: Seven articles were included. Each programme employed a cardiopulmonary exercise test before prescribing physical exercise. The most commonly used strategy was aerobic exercise, predominantly high-intensity interval training (HIIT) with intensities close to 90% of peak VO2, followed by continuous moderate-intensity exercise. Limb strength exercises were included in three programmes. CONCLUSIONS: The analysed literature suggests that cardiac rehabilitation in patients with ventricular assist devices is safe and can provide benefits in cardiorespiratory fitness and exercise tolerance. High-intensity interval training is identified as an appropriate strategy for achieving results, offering short-term improvements.

Veno-arterial ECMO ventricular assistance as a direct bridge to heart transplant: A single center experience in a low-middle income country.

INTRODUCTION: The use of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) as a direct bridge to heart transplantation (BTT) is not common in adults worldwide. BTT with ECMO is associated with increased early/mid-term mortality compared with other interventions. In low- and middle-income countries (LMIC), where no other type of short-term mechanical circulatory support is available, its use is widespread and increasingly used as rescue therapy in patients with cardiogenic shock (CS) as a direct bridge to heart transplantation (HT). OBJECTIVE: To assess the outcomes of adult patients using VA-ECMO as a direct BTT in an LMIC and compare them with international registries. METHODS: We conducted a single-center study analyzing consecutive adult patients requiring VA-ECMO as BTT due to refractory CS or cardiac arrest (CA) in a cardiovascular center in Argentina between January 2014 and December 2022. Survival and adverse clinical events after VA-ECMO implantation were evaluated. RESULTS: Of 86 VA-ECMO, 22 (25.5%) were implanted as initial BTT strategy, and 52.1% of them underwent HT. Mean age was 46 years (SD 12); 59% were male. ECMO was indicated in 81% for CS, and the most common underlying condition was coronary artery disease (31.8%). Overall, in-hospital mortality for VA-ECMO as BTT was 50%. Survival to discharge was 83% in those who underwent HT and 10% in those who did not, p < .001. In those who did not undergo HT, the main cause of death was hemorrhagic complications (44%), followed by thrombotic complications (33%). The median duration of VA-ECMO was 6 days (IQR 3-16). There were no differences in the number of days on ECMO between those who received a transplant and those who did not. In the Spanish registry, in-hospital survival after HT was 66.7%; the United Network of Organ Sharing registry estimated post-transplant survival at 73.1% ± 4.4%, and in the French national registry 1-year posttransplant survival was 70% in the VA-ECMO group. CONCLUSIONS: In adult patients with cardiogenic shock, VA-ECMO as a direct BTT allowed successful HT in half of the patients. HT provided a survival benefit in listed patients on VA-ECMO. We present a single center experience with results comparable to those of international registries.

Characterization of injuries and dressings of left ventricular assist device drivelines / Caracterización de lesiones y apósitos de drivelines de dispositivos de asistencia ventricular izquierda / Caracterização de lesões e curativos de drivelinesde dispositivos de assistência ventricular esquerda

Aim: To Identify and characterize driveline-related injuries among patients with HeartMate II® or HeartMate 3®and assess the dressings used during hospital stay. Method: Observational, cross-sectional study conducted between 2015 and 2023 at a large hospital in São Paulo, Brazil. Results: The sample consisted of 18 patients, with driveline injuries identified in 66.7%, categorized into stages one (83.3%), two (8.3%), and four (8.3%). Of these, 66.6% were diagnosed with driveline infection according to the Utah classification: stages two (50%), three (37.5%), and four (12.5%). A correlation was found between the occurrence of injuries and longer support time (p=0.035) and the presence of a diagnosis of driveline infections (p=0.013). The solutions most frequently used were Chloraprep™ (27.8%), Aqueous Chlorhexidine 0.5% (22.2%), and Saline 0.9% (22.2%), while the dressings were IV3000™ (72.2 %), Excilon™ (44.4%), and Biatain®Ag (33.3%). Conclusion: Driveline dressings are not standardized, indicating the need for new protocols and guidelines based on studies of high methodological quality and presenting robust evidence of the best solutions and dressings to prevent complications and promote better outcomes. (AU)

Objetivos: Identificar y caracterizar lesiones relacionadas con el driveline en pacientes con HeartMate II® o HeartMate 3® y evaluar los apósitos utilizados durante el ingreso hospitalario. Método: Estudio observacional, transversal, realizado entre 2015 y 2023, en un hospital de gran porte de São Paulo, Brasil. Resultados: La muestra estuvo conformada por 18 pacientes, identificándose lesiones de driveline en el 66,7%, categorizadas en estadios uno (83,3%), dos (8,3%) y cuatro (8,3%). De estos, el 66,6% fueron diagnosticados con infección de driveline con la clasificación de Utah en estadios dos (50%), tres (37,5%) y cuatro (12,5%). Hubo correlación entre la aparición de lesiones y el mayor tiempo de soporte (p=0,035) y la presencia del diagnóstico de infección del driveline (p=0,013). Las soluciones más frecuentes fueron Chloraprep™ (27,8%), Clorhexidina acuosa 0,5% (22,2%) y Salino 0,9% (22,2%), y los apósitos fueron IV3000™ (72,2%), Excilon™ (44,4%) y Biatain®Ag. (33,3%). Conclusión: Falta estandarización de los apósitos de drivelines, destacando la necesidad de nuevos protocolos y guías con estudios de alta calidad metodológica y con evidencia sólida sobre las mejores soluciones y coberturas, previniendo complicaciones y promoviendo mejores resultados. (AU)

Objetivos: Identificar e caracterizar as lesões relacionadas ao driveline em usuários de HeartMate II® ou HeartMate 3®e avaliar os curativos utilizados durante a internação hospitalar. Método: Estudo observacional, transversal, com dados analisados entre os anos de 2015 e 2023, em um hospital de grande porte de São Paulo, Brasil. Resultados: A amostra foi composta de 18 pacientes, sendo identificadas lesões de driveline em 66,7%, categorizadas em estágio um (83,3%), dois (8,3%) e quatro (8,3%). Destes, 66,6% apresentavam diagnóstico de infecção de driveline com a classificação de Utah de estágio dois (50%), três (37,5%) e quatro (12,5%). Houve correlação entre a ocorrência de lesões e o maior tempo de suporte (p=0,035) e a presença do diagnóstico de infecção do driveline (p=0,013). As soluções mais frequentes foram Chloraprep™ (27,8%), Clorexidina Aquosa 0,5% (22,2%) e Soro Fisiológico 0,9% (22,2%), e as coberturas IV3000™ (72,2%), Excilon™ (44,4%) e Biatain®Ag (33,3%). Conclusão: Nota-se ausência da padronização de curativos de drivelines, destacando a necessidade de novos protocolos e diretrizes com estudos de alta qualidade metodológica e com evidência robusta das melhores soluções e coberturas, prevenindo complicações e promovendo melhores resultados. (AU)

Human machine interface for ventricular assist devices applying health

BACKGROUND: Significant advancements in heart failure therapy are occur through the use of Ventricular Assist Devices (VADs). Cardiovascular diseases are the leading cause of death globally, affecting millions. Heart failure (HF) is a common condition, especially in patients over 65, and is linked to high rates of hospitalization, mortality, and readmissions. Heart transplant, while a treatment option for HF, faces significant challenges like donor scarcity and postoperative complications such as organ incompatibility, infections, and damage to other organs. Therefore, na efficient, lower-risk solution is sought. METHODS: Them VADs have emerged as a promising alternative. They can be used while waiting for a heart donor, as a bridge to recovery, or as definitive therapy. A key complication of VADs relates to the external controller, which is connected to the implanted pump via a percutaneous cable and can cause infections.To mitigate this, the Health 4.0 concept introduces the IoT concept like an implanted controller in the patient's body, reducing infection risk and enhancing quality of life. For interaction with this controller, a wireless Human-Machine Interface (HMI) is required. This interface allows control parameter adjustments for the VAD. Utilizing mobile devices for the HMI enables patients and doctors to access the VAD controller, removing the need for patients to be constantly connected to a nearby machine. Through the HMI, interaction with the VAD is possible, allowing real-time data display and information receipt for patient diagnosis. RESULTS: The HMI development for mobile devices allows patients and doctors to easily access the VAD controller, facilitating interactions such as displaying real-time data and receiving diagnostic information. Furthermore, doctors and caregivers can send commands to the controller, like adjusting the VAD. The proposed application contains monitoring screens with line graphs, user profile screens, command screens, and login screens, with authentication and authorization schemes. CONCLUSION: Designing and surgically introducing a fully implantable VAD is complex, but the benefits are vast. This approach not only reduces mortality rates but also improves patient quality of life, decreases infection risk. The fully implantable VAD represents advancement in medicine. As technology progresses, VADs evolve, becoming realistic and viable alternatives for patients ineligible for transplants. The project's development technology is Oracle Apex, a free low-code development platform that allows the creation of applications using pre-defined HTML, CSS, and JavaScript templates. The data sent by the controller will bestored in separate tables, such as blood temperature and heartbeat tables. With data collection and analysis from the VAD, valuable information for patient diagnosis and monitoring can be provided using IoT and the big data concept, enabling more in-depth studies through cloud computing using the stored data.

Noncardiac Surgery in Patients with Left Ventricular Assist Devices: A 11-Year Institutional Experience.

INTRODUCTION: Limited options in the end-stage treatment of heart failure have led to increased use of left ventricular assist devices. For this reason, the rate of non-cardiac surgeries in patients with left ventricular assist devices is also increasing. Our study aims to analyze surgical rate, anesthesia management, and results by reviewing our 11-year experience with patients who underwent non-cardiac surgery receiving left ventricular assist devices support. METHODS: We retrospectively evaluated 57 patients who underwent non-cardiac surgery and 67 non-cardiac surgical procedures among 274 patients who applied between January 2011 and December 2022 and underwent left ventricular assist devices implantation with end-stage heart failure. RESULTS: Fifty (74.6%) patients with left ventricular assist devices admitted to the hospital for non-cardiac surgery were emergency interventions. The most common reasons for admission were general surgery (52.2%), driveline wound revision (22.3%), and neurological surgery (14.9%). This patient group has the highest in-hospital mortality rate (12.8%) and the highest rate of neurological surgery (8.7%). While 70% of the patients who underwent neurosurgery were taken to surgery urgently, the International Normalized Ratio values of these patients were between 3.5 and 4.5 at the time of admission to the emergency department. CONCLUSION: With a perioperative multidisciplinary approach, higher morbidity and mortality risks can be reduced during emergencies and major surgical procedures.

The Effects of Exercise on Cardiogenic Shock with an Intra-Aortic Balloon Pump: A Case Report. / Efeitos do Exercício em Choque Cardiogênico e Balão Intra-Aórtico: Um Relato de Caso.

This case report describes the exercise program on a hospitalized 54-year-old male patient with cardiogenic shock waiting for a heart transplant assisted by an intra-aortic balloon pump, a temporary mechanical circulatory support device. The temporary mechanical circulatory support device, an intra-aortic balloon pump, was placed in the left subclavian artery, enabling the exercise protocol. Measurements and values from Swan-Ganz catheter, blood sample, brain natriuretic peptide (NT-proBNP), and high-sensitivity C-reactive protein (hs-CRP), as well as the six-minute walk test (6MWT) and venous oxygen saturation (SvO2) were obtained before and after an exercise protocol. The exercise training protocol involved the use of an unloaded bed cycle ergometer once a day, for a maximum of 30 minutes, to the tolerance limit. No adverse events or events related to the dislocation of the intra-aortic balloon pump were observed during the exercise protocol. The exercise program resulted in higher SvO2 levels, with an increased 6MWT with lower Borg dyspnea scores (312 meters vs. 488 meters and five points vs. three points, respectively). After completing the ten-day exercise protocol, the patient underwent a non-complicated heart transplant surgery and a full recovery in the ICU. This study showed that exercise is a feasible option for patients with cardiogenic shock who are using an intra-aortic balloon pump and that it is well-tolerated with no reported adverse events.

O presente relato de caso descreve o programa de exercícios aplicado a um paciente do sexo masculino, de 54 anos, internado com choque cardiogênico, aguardando transplante cardíaco e assistido por balão intra-aórtico, um dispositivo de suporte circulatório mecânico temporário. O dispositivo de suporte circulatório mecânico temporário, um balão intra-aórtico, foi colocado na artéria subclávia esquerda, possibilitando o protocolo de exercícios. Antes e após um protocolo de exercícios, foram obtidos dados a partir de cateter de Swan-Ganz, amostra de sangue, peptídeo natriurético cerebral (NT-proBNP), proteína C reativa de alta sensibilidade (PCR-as), teste de caminhada de seis minutos (TC6min) e medição da saturação venosa de oxigênio (SvO2). O protocolo de treinamento físico envolveu a utilização de um cicloergômetro adaptado ao leito, sem carga, uma vez ao dia, por no máximo 30 minutos, até o limite da tolerância. Não foram observados eventos adversos tampouco relacionados ao deslocamento do balão intra-aórtico durante o protocolo de exercícios. O programa de exercícios resultou em maior SvO2 com aumento do TC6min e menores escores de dispneia de Borg (312 metros vs. 488 metros e cinco pontos vs. três pontos, respectivamente). Após completar o protocolo de exercícios de dez dias, o paciente foi submetido a uma cirurgia de transplante cardíaco sem complicações e recuperação total na UTI. O presente estudo demonstrou que o exercício é uma opção viável para pacientes com choque cardiogênico em uso de balão intra-aórtico e que é bem tolerado, além de não haver relatos de eventos adversos.

Embedded cyber-physical system for physiological control of ventricular assist devices

Ventricular Assist Devices (VADs) play a crucial role in both bridging to transplantation and serving as destination therapy for congestive heart failure (CHF) management. This study aims to address the limitations of existing control strategies for VADs, specifically their inability to adapt automatically to hemodynamic changes. It proposes a novel embedded cyber-physical system (CPS) based on real-time data processing, reconfigurable architecture, and communication protocols aligned with Health 4.0 concepts to enhance physiological control over VADs (PC-VAD). The research employs a multi-objective PC-VAD approach within a hybrid cardiovascular simulator. An embedded CPS is introduced to overcome challenges related to differences in controller characteristics between computers and embedded systems. The study assesses the performance of the embedded CPS by comparing it with a computer-based control system. The embedded CPS demonstrates outcomes comparable to the computer-based control system, maintaining mean arterial pressure and cardiac output at physiological levels. Even in the face of variations in ejection fraction, the embedded CPS dynamically adjusts the pump's rotational speed based on simulated clinical conditions. Notably, there is no aortic reflux to the ventricle through the VAD during testing. These findings affirm the satisfactory control performance of the embedded CPS in regulating VADs. The study concludes that the embedded CPS effectively addresses the limitations of current VAD control strategies, exhibiting control performance comparable to computer-based systems. However, further experimentation and in vivo studies are necessary to validate and ensure its applicability in real-world scenarios.

Biofunctionalization of surfaces to minimize undesirable effects in cardiovascular assistance devices

BACKGROUND: The reactivity of blood with non-endothelial surface is a challenge for long-term Ventricular Assist Devices development, usually made with pure titanium, which despite of being inert, low density and high mechanical resistance it does not avoid the thrombogenic responses. Here we tested a modification on the titanium surface with Laser Induced Periodic Surface Structures followed by Diamond Like Carbon (DLC) coating in different thicknesses to customize the wettability profile by changing the surface energy of the titanium. METHODS: Four different surfaces were proposed: (1) Pure Titanium as Reference Material (RM), (2) Textured as Test Sample (TS), (3) Textured with DLC 0.3µm as (TSA) and (4) Textured with 2.4µm DLC as (TSB). A single implant was positioned in the abdominal aorta of Wistar rats and the effects of hemodynamic interaction were evaluated without anticoagulant drugs. RESULTS: After twelve weeks, the implants were extracted and subjected to qualitative analysis by Scanning Electron Microscopy under low vacuum and X-ray Energy Dispersion. The regions that remained in contact with the wall of the aorta showed encapsulation of the endothelial tissue. TSB implants, although superhydrophilic, have proven that the DLC coating inhibits the adhesion of biological material, prevents abrasive wear and delamination, as observed in the TS and TSA implants. Pseudo- neointimal layers were heterogeneously identified in higher concentration on Test Surfaces.

Registro multicéntrico impella CP para shock cardiogénico o angioplastía de alto riesgo protegida en Chile / Use of impella CP in high risk coronary angioplasty and cardiogenic shock: a registry

Antecedentes: El Shock Cardiogénico (SC) y las Angioplastías de Alto Riesgo (AAR) están asociadas con altas tasas de mortalidad. El uso del dispositivo Impella CP podría reducir el riesgo de muerte en estos escenarios. En Chile no existen reportes evaluando el uso del dispositivo Impella CP. Objetivo: Analizar los desenlaces clínicos en pacientes que fueron sometidos al uso del dispositivo Impella CP por SC o por AAR. Métodos: Se realizó un estudio retrospectivo en 17 pacientes, los cuales representan el total de implantes realizados en el país, entre octubre 2021 y agosto 2023. Se describió las características, demográficas, procedimentales y después del implante. Se estimó la mortalidad general y se identificaron factores asociados. Resultados: La edad de los pacientes fue 69± 3,7 años y 88,2% fueron hombres. El 64,7% recibió el dispositivo por SC y 35,3% por AAR. Dentro de las comorbilidades estudiadas, la hipertensión arterial fue la más frecuente, 94,1%. Un 58,8% de los pacientes fueron revascularizados a través de la arteria radial. El 29,4% recibió el dispositivo previo a la angioplastía y 70,6% lo recibió después. El 47,1% de las angioplastías fue guiada por imágenes. En 11,8% de ellos se realizó litotricia intracoronaria y 5,9% por ablación intracoronaria. Los pacientes estuvieron 13 ±3,4 días con el soporte. La mortalidad global fue de 41,2%. Conclusiones: El uso del dispositivo Impella presentó pocas complicaciones vasculares. La mortalidad asociada con su colocación en Chile fue relativamente similar con la reportada en la literatura.

Background: Cardiogenic shock and high-risk Angioplasty are associated with a high mortality rate. Using the Impella CP device could reduce the risk of death in these scenarios. In Chile, there are no studies evaluating the use of the Impella CP device. Objective: To analyse the clinical outcomes in patients who have undergone placement of the Impella CP device for cardiogenic shock and high-risk angioplasties. Methods: A retrospective study was carried out on 17 patients, which represent the total number of implants performed in the country, between October 2021 and August 2023. The demographic, procedural and post-implant characteristics were described. Overall mortality and associated factors were identified. Results: The age was 69± 3.7 years, where 88.2% were men. 64.7% of patients received the device by SC and 35.3% by AAR. Among the comorbidities studied, arterial hypertension was the most frequent with 94.1%. 58.8% of patients were revascularized through the radial artery. 29.4% of patients received the device before angioplasty and 70.6% received it afterwards. 47.1% of angioplasties were image-guided, 11.8% had intracoronary lithotripsy, and 5.9% had intracoronary ablation. The patients spent 13 ±3.4 days with the support. Overall mortality was 41.2%. Conclusion: use of the Impella device was associated with few vascular complications. Mortality associated with use of the Impella device in Chile was similar to that previously reported in other studies.

Fulminant Lymphocytic Myocarditis Successfully Managed with Intra-Aortic Balloon Pump and Extracorporeal Membrane Oxygenation: A Case Report.

BACKGROUND Lymphocytic myocarditis (LM) is a rare inflammatory disease of the heart. The clinical presentation of LM varies from mild flu-like symptoms to fulminant myocarditis with cardiogenic shock. Fulminant myocarditis has a poor prognosis and the usual treatment is inotropes with or without ventricular assist devices such as intra-aortic balloon pump (IABP) and venoarterial extracorporeal membrane oxygenation (V-A ECMO). We report the case of fulminant LM with severe cardiogenic shock that was successfully treated with concomitant use of IABP and V-A ECMO. CASE REPORT A 32-year-old woman with no medical history presented to the Emergency Department (ED) with chest pain with irradiation to the left upper limb, worse when supine. The electrocardiogram (ECG) on admission showed sinus rhythm with nonspecific ST-T repolarization abnormalities, and laboratory results showed elevated ultrasensitive troponin and C-reactive protein. Transthoracic echocardiography (TTE) showed left ventricular ejection fraction (LVEF) of 25% and diffuse hypokinesis. On the next day, she developed cardiogenic shock requiring vasoactive drugs, IABP, and V-A ECMO. Pulse therapy with methylprednisolone was started. Endomyocardial biopsy (EMB) revealed acute LM, and intravenous human immunoglobulin was administered. The patient evolved with progressive clinical improvement, being discharged 56 days after admission, with an improvement in the LVEF to 55%. CONCLUSIONS Fulminant LM is a rare and potentially fatal condition that requires immediate intervention. The combination of IABP and V-A ECMO among patients with LM-cardiogenic shock may provide survival benefits.

Treatment of fungal infection on left ventricle assist device driveline exit site: a case report and systematic review.

OBJECTIVE: The use of ventricular assist devices (VAD) is increasing; however, diagnosis and management of device complications, such as the driveline exit site (DES) being the portal of entry for fungal infection, is not well known. METHOD: A systematic review involving searching PubMed (2005 to July 2020) was conducted. The case of a 43-year-old female patient who had a left VAD (LVAD) (HeartMate 3, Abbott, US) is also reported. RESULTS: The patient was successfully treated with ketoconazole cream and oral fluconazole for likely superficial DES fungal infections. We included 36 studies that met our inclusion criteria; however, only one was included in our review. In the literature, five cases of DES fungal infection were reported, with Candida being the only fungal pathogen. CONCLUSION: LVAD fungal infections are uncommon but can be responsible for high mortality rates, require a prolonged period of treatment, and can present a huge problem when surgical alternatives are not available. However, Candida species are most common. Fungal infections can only produce clear discharge, and so the classic definition of driveline infection based on purulent secretion can vary. Negative skin culture does not exclude the diagnosis of infection of the DES, and so empirical diagnosis may only be clinically based.

Driveline dressings used in heartmate patients and local complications: A retrospective cohort.

BACKGROUND: Patients with long-term ventricular assist devices (VAD) are predisposed to infection, bleeding, and pressure injuries at the insertion of the driveline. There is no consensus on a driveline dressing protocol. Chlorhexidine is often used to clean the driveline exit site and has been associated with lower rates of infection. For driveline coverage, bacteriostatic agents and transparent film have shown good results, but are costly. The same issue was associated with anchorage devices. OBJECTIVES: The purpose of this study was to evaluate the types of dressings used in the driveline of patients using HeartMate (HM) and to describe the incidence density of local complications (infection, bleeding, and pressure injury) within 30 days postoperatively. METHODS: A retrospective cohort study was conducted and included 22 patients admitted to the Intensive Care Unit after implantation of HM II and III in a Brazilian private hospital. RESULTS: Several types of dressings were used in the drivelines. There were 22 different types of dressings. Dressing type 6 (Chlorhexidine, Excilon, Gauze and IV3000) were the most used (45.4%). Subjects using the Flexi-Trak anchoring device had a higher rate of local bleeding (50.0%) and those who used the Hollister device had more infection (61.1%) and pressure injury associated with a medical device (11.1%), compared to others. Infection was the primary complication (45.4%), followed by local bleeding (27.7%). CONCLUSION: Despite the high variability of products used in the driveline of patients using HeartMate, the dressing made with chlorhexidine, silver-impregnated absorbent foam and transparent film, and the use of anchoring devices was the most frequently used. Infection was the most common complication.

Brushless speed control for a novel brazilian axial ventricular assist device

OBJECTIVES: The reduction in size of these systems, which increases their reliability, biocompatibility and robustness, is essential to the complete implantation of the VADs, which is the main focus of the current state of art. Continuous flow VADs are actuated by brushless motors due to their reliability. The objective of the current project was to implement and simulate sensorless speed control in order to actuate VAD. METHODS: In order to increase the robustness of the system even further, a strategy that does not use Hall sensors can be implemented. The sensorless strategy to control speed that was implemented in this work aims to detect the position of the rotor by using the coil of the inactive phase in order to sense the variation in magnetic flux, which comes in the form of back-electromotive forces. RESULTS: A three phase inverter to electrically commute the motor's phases, a conditioning circuit that obtains the back-electromotive forces and a speed controller were developed. The speed control and the commutation logic were implemented by using a microcontroller. The results that were obtained in computational simulations indicated that the three-phase inverter, the commutation logic and the controller reached the project requirements. The implemented microcontroller commutation logic presented the expected behavior. Commutation signals were obtained in six stages, necessary for the correct activation of the phases of the brushless motor. The controller was validated in terms of its step response, demonstrating low overshoot and fast control action in the system. CONCLUSIONS: To further enhance the robustness of the system, an alternative strategy that eliminates the use of Hall sensors can be employed. The sensorless speed control strategy, implemented in this study, detects the position of the rotor by measuring variations in magnetic flux through the coil of the inactive phase, thus relying on back-electromotive forces for detection.

Computational fluid dynamics improvements and in vitro tests of a proposed transventricular axial blood pump

Heart failure is a chronic disease that affects thousands of people around the world, being characterized by the inability of one's heart to adequately pump their blood according to their body's needs. Its treatment may be performed through heart transplant. However, ventricular assist devices (VADs) can be used as a way to assist the patient while they wait for a transplant or as destination therapy, with them being responsible for the patients increase in the life expectancy. These devices are pumps that help supply the adequate cardiac output to the body. But the procedures used to implant this kind of device, the size and geometry of the pump are vital for the surgery success and assurance safety patient recuperation. Because of that many important researches center try to find pump geometry that comply these characteristics and comply human blood physiology. Then the reduction in size of these systems, which increases their reliability, biocompatibility and robustness, is essential to the complete implantation of the VADs, which is the main focus of the current state of art.

Mechanical Circulatory Assistance in Children: Clinical Outcome.

BACKGROUND: In countries where organ donation is scarce, mortality in the pediatric heart transplant waiting list is high, and ventricular assist devices (VADs) are therapeutic alternatives in these situations. Berlin Heart EXCOR is currently 1 of the few VADs specific for children. METHODS: This retrospective study includes pediatric patients who underwent Berlin Heart EXCOR placement in a Brazilian hospital between 2012 and 2021. Clinical and laboratory data at the time of VAD implantation and the occurrence of complications and outcomes (success as a bridge to transplant or death) were analyzed. RESULTS: Eight patients, from 8 months to 15 years, were included: 6 with cardiomyopathy and 2 with congenital heart disease. Six were on Intermacs 1 and 2 on Intermacs 2. The most common complications observed were stroke and right ventricular dysfunction. Six were transplanted, and 2 died. Those submitted to transplant had a higher mean weight than those who died, with no statistically significant difference. The underlying disease had no impact on the outcome. The group undergoing transplant had lower brain natriuretic peptide and lactate values, but no laboratory variable showed a statistically significant difference in the outcome. CONCLUSION: A VAD is an invasive treatment with potentially serious adverse effects and is still poorly available in Brazil. However, as a bridge to transplant, it is a useful treatment for children in progressive clinical decline. In this study, we did not observe any clinical or laboratory factor at the time of VAD implantation that implied better outcomes.

Cumplimiento de los objetivos nutricionales durante el uso de dispositivos de asistencia ventricular / Nutritional objectives in patients with ventricular assist devices

Antecedentes: Los dispositivos de asistencia ventricular (VAD, sigla en inglés) se utilizan cada vez más para el manejo de la insuficiencia cardíaca descompensada en unidades de cuidados intensivos. El manejo nutricional es fundamental para la evolución clínica de estos pacientes. Objetivos: El objetivo fue evaluar en cuánto tiempo se puede alcanzar las necesidades nutricionales, utilizando distintas modalidades de apoyo nutricional, en pacientes que requirieron asistencia con VAD por insuficiencia cardíaca aguda en una clínica privada del país. Métodos: En una clínica privada se efectuó un estudio observacional retrospectivo analizando los datos clínicos relacionados al aporte nutricional de 12 pacientes que requirieron asistencia con VAD. Las vías de aporte nutricional evaluadas fueron la nutrición enteral (NE) y/o nutrición parenteral (NP). Se midió el tiempo de implementación del apoyo nutricional y su efecto se estimó por una valoración nutricional subjetiva y por la medición de indicadores de laboratorio. Además, se vigilaron las complicaciones asociadas al aporte nutricional. Resultados: El estudio incluyó a 12 pacientes. Los objetivos nutricionales se alcanzaron por completo en el 91% de los pacientes (n=11) en 3,7 ± 1 días después de iniciado el apoyo nutricional. En ese momento, 5 pacientes recibían NE exclusiva, 4 pacientes NP complementaria a la NE, 1 paciente NE complementaria a la alimentación oral y 1 paciente con vía oral. Al momento de alcanzar los requerimientos nutricionales ningún paciente tenía NP exclusiva. Conclusión: Concluimos que el apoyo nutricional precoz es factible y seguro en pacientes con VAD. Alcanzar los objetivos nutricionales es posible sin efectos adversos graves. Se necesitan estudios futuros para determinar el beneficio a largo plazo del apoyo nutricional agresivo para pacientes en estado crítico que requieren apoyo hemodinámico.

Background: Ventricular assist devices (VAD) are being used more frequently in patients with severe heart failure. Nutritional support is a critical factor for the outcome in these patients. Aim: to evaluate the time required and mode of nutritional support in patients with severe cardiac dysfunction being treated with VAD. Methods: 12 patients with VAD being treated in an intensive care unit were evaluated to determine the time and mode of support required to achieve adequate nutrition. Enteral and / or parenteral modes of nutritional support were used. The outcomes were evaluated by subjective appreciation, weight measurement and serum levels of albumin, pre-albumin and vitamin D. Results: Adequate nutritional support was achieved in 91% of patients a mean of 3 days after beginning of treatment (SD 1 day). At that time 5 patients were receiving only enteral nutrition, 4 patients enteral and parenteral nutrition, 1 patient enteral nutrition in addition to oral nutrition and 1 patients was receiving only oral nutrition. No patient was receiving only parenteral nutrition. Conclusion: early nutritional support is posible and safe in patients with an VAD. Further studies are needed to evaluate long term benefits of this strategy of nutritional support.