Comprehensive review of hemolysis in ventricular assist devices

Ventricular assist devices(VADs)have played an important role in altering the natural history of end-stage heart failure.Low-grade hemolysis has been traditionally described in patients with VADs,indicating effective device functionality.However,clinically significant hemolysis could be crucial in terms of prognosis,calling for prompt therapeutic actions.The absence of solid and widely approved diagnostic criteria for clinically significant hemolysis,render the utilization of hemolysis laboratory markers challenging.Hemolysis incidence varies(5%-18%)depending on definition and among different VAD generations,being slightly higher in continuous-flow devices than in pulsatile devices.Increased shear stress of red blood cells and underlying device thrombosis appear to be the main pathogenetic pathways.No certain algorithm is available for the management of hemolysis in patients with VADs,while close clinical and laboratory monitoring remains the cornerstone of management.Imaging examinations such as echocardiography ramp test or computed tomography scan could play a role in revealing the underlying cause.Treatment should be strictly personalized,including either pharmacological(antithrombotic treatment)or surgical interventions.

Treatment of gastrointestinal bleeding in left ventricular assist devices:A comprehensive review

Left ventricular assist devices(LVAD)are increasingly become common as life prolonging therapy in patients with advanced heart failure.Current devices are now used as definitive treatment in some patients given the improved durability of continuous flow pumps.Unfortunately,continuous flow LVADs are fraught with complications such as gastrointestinal(GI)bleeding that are primarily attributed to the formation of arteriovenous malformations.With frequent GI bleeding,antiplatelet and anticoagulation therapies are usually discontinued increasing the risk of life-threatening events.Small bowel bleeds account for 15%as the source and patients often undergo multiple endoscopic procedures.Treatment strategies include resuscitative measures and endoscopic therapies.Medical treatment is with octreotide.Novel treatment options include thalidomide,angiotensin converting enzyme inhibitors/angiotensinⅡreceptor blockers,estrogen-based hormonal therapies,doxycycline,desmopressin and bevacizumab.Current research has explored the mechanism of frequent GI bleeds in this population,including destruction of von Willebrand factor,upregulation of tissue factor,vascular endothelial growth factor,tumor necrosis factor-α,tumor growth factor-β,and angiopoetin-2,and downregulation of angiopoetin-1.In addition,healthcare resource utilization is only increasing in this patient population with higher admissions,readmissions,blood product utilization,and endoscopy.While some of the novel endoscopic and medical therapies for LVAD bleeds are still in their development stages,these tools will yet be crucial as the number of LVAD placements will likely only increase in the coming years.

Effects of medically generated electromagnetic interference from medical devices on cardiac implantable electronic devices: A review

As cardiac implantable electronic devices(CIED)become more prevalent,it is important to acknowledge potential electromagnetic interference(EMI)from other sources,such as internal and external electronic devices and procedures and its effect on these devices.EMI from other sources can potentially inhibit pacing and trigger shocks in permanent pacemakers(PPM)and implantable cardioverter defibrillators(ICD),respectively.This review analyzes potential EMI amongst CIED and left ventricular assist device,deep brain stimulators,spinal cord stimulators,transcutaneous electrical nerve stimulators,and throughout an array of procedures,such as endoscopy,bronchoscopy,and procedures involving electrocautery.Although there is evidence to support EMI from internal and external devices and during procedures,there is a lack of large multicenter studies,and,as a result,current management guidelines are based primarily on expert opinion and anecdotal experience.We aim to provide a general overview of PPM/ICD function,review documented EMI effect on these devices,and acknowledge current management of CIED interference.

Heart and Lung Mechanical Assist Devices are Comprehensively Tested by the New Hybrid Simulators

Two applications of the hybrid simulators have been presented as examples: nonpulsatile VAD interaction with lumped parameters cardiovascular system numerical model and respirator interacting with the Dubois numerical model of obstructive lung diseases. The results of simulations showed how the tested assist devices change biological system - assist device characteristics in the course of heart or lungs diseases and how it influences pressure and flow in a particular point of cardiovascular or respiratory system numerical model.

Combined Application of Circulatory Assist Devices Following Cardiac Arrest in Patients after Cardiac Surgery

Objectives To evaluate retrospectively the potential benefits of combined utilization of various assisted circulation devices in cardiac arrest patients who did not respond to conventional cardiopulmonary cerebral resuscitation （CPCR）. Methods Assisted circulation devices, including emergency cardiopulmonary bypass （ECPB）, intra-aortic balloon pump （IABP）, and left ventricular assist device （LVAD）, were applied to 16 adult patients who had cardiac arrest 82 rain-56 h after open heart surgery and did not respond to 20 rain or longer conventional CPCR. ECPB was applied to 2 patients, ECPB plus IABP to 8 patients, ECPB plus IABP and LVAD to 6 patients. Results One patient recovered fully and one patient died. Of the other 14 patients, 13 resumed spontaneous cardiac rhythm and one did not; none of them could be weaned from ECPB. Further treatment of the 14 patients with combinations of assisted circulation devices enabled 6 patients to recover. One of the 7 recovered patients died of reoccurring cardiac arrest after 11 days; the other 6 were discharged in good condition and were followed up for 3-49 months （mean =22 months）. Of the 6 discharged patients one suffered cerebral embolism during LVAD treatment, resulting in mild limitation of mobility of the right limbs ; the other 5 never manifested any central nervous system complications. There was no late deaths giving a 37.5% （6/16） long-term survival rate. Conclusions ECPB could effectively reestablish blood circulation and oxygen supply, rectify acidosis, and improve internal milieu. The combined utilization of ECPB, IABP, and LVAD reduces the duration of ECPB, improves the incidence of recovery, and offers beneficial alternatives to refractory cardiac arrest patients.

Cap-assisted endoscopy for esophageal foreign bodies:A metaanalysis

BACKGROUND Esophageal foreign bodies are common around the world.Newer approaches,such as cap-assisted endoscopy,have been introduced as an alternative to conventional methods.Therefore,we performed a meta-analysis ono cap-assisted endoscopy versus conventional endoscopy for removal of esophageal foreign bodies.AIM To investigated the effectiveness of cap-assisted endoscopy with conventional endoscopy.METHODS An extensive literature search was performed(December 2021).For esophageal foreign body removal,cap-assisted endoscopy was compared to conventional endoscopy for procedure time,technical success of the procedure,time of foreign body retrieval,en bloc removal,and adverse event rate using odds ratio and mean difference.RESULTS Six studies met the inclusion criteria(n=1305).Higher odds of technical success(P=0.002)and en bloc removal(P<0.01)and lower odds of adverse events(P=0.02)and foreign body removal time(P<0.01)were observed with cap-assisted endoscopy as compared to conventional techniques.CONCLUSION For esophageal foreign bodies,the technique of cap-assisted endoscopy demonstrated increased en bloc removal and technical success with decreased time and adverse events as compared to conventional techniques.

Enteroscopy in children and adults with inflammatory bowel disease

Inflammatory bowel disease(IBD)includes Crohn’s disease(CD),ulcerative colitis and unclassified entities.CD commonly involves the terminal ileum and colon but at the time of diagnosis it can be confined to the small bowel(SB)in about 30%of the patients,especially in the young ones.Management of isolated SB-CD can be challenging and objective evaluation of the SB mucosa is essential in differentiating CD from other enteropathies to achieve therapeutic decisions and to plan the follow-up.The introduction of cross-sectional imaging techniques and capsule endoscopy(CE)have significantly expanded the ability to diagnose SB diseases providing a non-invasive test for the visualization of the entire SB mucosa.The main CE limitations are the low specificity,the lack of therapeutic capabilities and the impossibility to take biopsies.Device assisted enteroscopy(DAE)enables histological confirmation when traditional endoscopy,capsule endoscopy and cross-sectional imaging are inconclusive and also allows therapeutic interventions such as balloon stricture dilation,intralesional steroid injection,capsule retrieval and more recently stent insertion.In the current review we will discuss technical aspect,indications and safety profile of DAE in children and adults with IBD.

Design and Implementation of a System for Laser Assisted Milling of Advanced Materials

Laser assisted machining is an effective method to machine advanced materials with the added benefits of longer tool life and increased material removal rates. While extensive studies have investigated the machining properties for laser assisted milling（LAML）, few attempts have been made to extend LAML to machining parts with complex geometric features. A methodology for continuous path machining for LAML is developed by integration of a rotary and movable table into an ordinary milling machine with a laser beam system. The machining strategy and processing path are investigated to determine alignment of the machining path with the laser spot. In order to keep the material removal temperatures above the softening temperature of silicon nitride, the transformation is coordinated and the temperature interpolated, establishing a transient thermal model. The temperatures of the laser center and cutting zone are also carefully controlled to achieve optimal machining results and avoid thermal damage. These experiments indicate that the system results in no surface damage as well as good surface roughness, validating the application of this machining strategy and thermal model in the development of a new LAML system for continuous path processing of silicon nitride. The proposed approach can be easily applied in LAML system to achieve continuous processing and improve efficiency in laser assisted machining.

Construction of Bioartificial Renal Tubule Assist Device In Vitro and Its Function of Transporting Sodium and Glucose

To explore a new way of constructing bioartificial renal tubule assist device （RAD） in vitro and its function of transporting sodium （Na^＋） and glucose and to evaluate the application of atomic force microscope in the RAD construction, rat renal tubular epithelial cell line NRK-52E was cultured in vitro, seeded onto the outer surfaces of hollow fibers in a bioreactor, and then cultured for two weeks to construct RAD. Bioreactor hollow fibers without NRK-52E cells were used as control. The morphologies of attached cells were observed with scanning electron microscope, and the junctions of cells and polysulfone membrane were observed with atomic force microscope. Transportation of Na＋ and glucose was measured. Oubaine and phlorizin were used to inhibit the transporting property. The results showed that NRK-52E cells and polysulfone membrane were closely linked, as observed under atomic force microscope. After exposure to oubaine and phlorizin, transporting rates of Na^＋ and glucose were decreased significantly in the RAD group as compared with that in the control group （P〈0.01）. Furthermore, when the inhibitors were removed, transportation of Na^＋ and glucose was restored. It is concluded that a new RAD was constructed successfully in vitro, and it is able to selectively transport Na^＋ and glucose.

Computational fluid dynamics of left ventricular assist device under unsteady flow

Left ventricular assist device( LVAD) in this study is a mechanical tool that is used to support blood flow in the patient with heart disease. It supports left ventricle by building up the pressure to the pump outlet connected to the aorta. This pump was designed based on the magnetic driven centrifugal pump with a unique small washout hole constructed inside the impeller to generate the washout flow passage to prevent the stagnation at the region underneath and around the rotor. Computational fluid dynamics( CFD) was adopted in this study to assess the performance and optimize the design to avoid recirculation and high shear stress which is the main cause of stagnation and blood damage. Transient simulation was used for this study due to the asymmetric design of the washout hole and the complication of the bottom support of the impeller that has a risk of thrombosis,also,it was used to predict the variation of hydraulic performance caused by the rotation of the impeller and pulsed flow at the pump inlet. The simulation results show no excessive stress and no recirculation observed within the computational domain; in addition,the research result also provides information for further optimization and development to the pump.

Cardiac rehabilitation in a heart failure patient after left ventricular assist device insertion and subsequent heart transplantation:A case report

BACKGROUND Insertion of a left ventricular assist device(LVAD)and heart transplantation(HT)improve the survival of patients with heart failure.In addition,cardiac rehabilitation(CR)further increases the functional capacity.This case report describes a successful case of CR after LVAD insertion and subsequent HT.CASE SUMMARY In the present case,during the LVAD insertion period,peak oxygen consumption(VO2)increased by 12.16%after CR.HT was performed 7 mo after the LVAD insertion,and the patient participated in phases I and II CR.The peak VO2 increased from 17.24 to 22.29 m L/kg/min.This improvement was more significant than that reported in previous studies on CR after LVAD insertion or HT.The patient’s quality of life also improved.The total average score of the short form-36 questionnaire increased from 29.5 points at admission to 53.3 points 9 mo after HT.CONCLUSION A tailored CR program after LVAD insertion or HT may improve the patients’quality of life and increase survival.

In-depth review of cardiopulmonary support in COVID-19 patients with heart failure

Coronavirus disease 2019 infection has spread worldwide and causing massive burden to our healthcare system.Recent studies show multiorgan involvement during infection,with direct insult to the heart.Worsening of the heart function serves as a predictor of an adverse outcome.This finding raises a particular concern in high risk population,such as those with history of preexisting heart failure with or without implantable device.Lower baseline and different clinical characteristic might raise some challenge in managing either exacerbation or new onset heart failure that might occur as a consequence of the infection.A close look of the inflammatory markers gives an invaluable clue in managing this condition.Rapid deterioration might occur anytime in this setting and the need of cardiopulmonary support seems inevitable.However,the use of cardiopulmonary support in this patient is not without risk.Severe inflammatory response triggered by the infection in combination with the preexisting condition of the worsening heart and implantable device might cause a hypercoagulability state that should not be overlooked.Moreover,careful selection and consideration have to be met before selecting cardiopulmonary support as a last resort due to limited resource and personnel.By knowing the nature of the disease,the interaction between the inflammatory response and different baseline profile in heart failure patient might help clinician to salvage and preserve the remaining function of the heart.

Effects of left ventricular assist device on pulmonary functions and pulmonary hemodynamics:A meta-analysis

BACKGROUND Given current evidence,the effect of left ventricular assist device(LVAD)implantation on pulmonary function tests remains controversial.AIM To better understand the factors contributing to the changes seen on pulmonary function testing and the correlation with pulmonary hemodynamics after LVAD implantation.METHODS Electronic databases were queried to identify relevant articles.The summary effect size was estimated as a difference of overall means and standard deviation on a random-effects model.RESULTS A total of four studies comprising 219 patients were included.The overall mean forced expiratory volume in one second(FEV1),forced vital capacity(FVC)and diffusion lung capacity of carbon monoxide(DLCO)after LVAD implantation were significantly lower by 0.23 L(95%CI:0.11-0.34,P=00002),0.18 L(95%CI:0.03-0.34,P=0.02),and 3.16 mmol/min(95%CI:2.17-4.14,P<0.00001),respectively.The net post-LVAD mean value of the cardiac index was significantly higher by 0.49 L/min/m2(95%CI:0.31-0.66,P<0.00001)compared to pre-LVAD value.The pulmonary capillary wedge pressure and pulmonary vascular resistance were significantly reduced after LVAD implantation by 8.56 mmHg(95%CI:3.78-13.35,P=0.0004),and 0.83 Woods U(95%CI:0.11-1.55,P=0.02),respectively.There was no significant difference observed in the right atrial pressure after LVAD implantation(0.61 mmHg,95%CI:-2.00 to 3.32,P=0.65).Overall findings appear to be driven by studies using HeartMateII devices.CONCLUSION LVAD implantation might be associated with a significant reduction of the spirometric measures,including FEV1,FVC,and DLCO,and an overall improvement of pulmonary hemodynamics.

Anesthetic management for the patients with cardiac transplant

With the advancement of medical technique and application of the new immunosuppressant agents, cardiac transplantation has become an effective treatment for end-stage heart disease caused by different reasons. The orthotopic procedure has been performed in many countries nowadays. Whether it is successful or not mainly depends on harvesting the denoted heart, operative technique and perioperative management.

Right Ventricular Failure Following Left Ventricular Assist Device Implantation

Left ventricular assist device (LVAD) is being used increasingly in recent years for end stage heart failure as a bridge to transplant (BTT) and also as a destination therapy (DT). Patients with end stage heart failure have some degree of elevated pulmonary capillary wedge pressure, causing right ventricular hypertrophy which in due course leads to decreased dilatation of the RV and fall in cardiac output & severe tricuspid regurgitation (TR) presenting with features of RV failure (RVF). Implantation of LVAD improves left heart function at the cost of right ventricular output with an incidence of 25%-30%. RVF may lead to impaired LVAD flow, difficulty in weaning from cardio-pulmonary bypass (CPB), decreased tissue perfusion and multi-organ failure. In this article we comprehended the pathophysiology leading to RVF post LVAD implantation and its preoperative predictors and the various treatment modalities for managing RVF post LVAD implantation.

Recovery after acute kidney injury requiring kidney replacement therapy in patients with left ventricular assist device: A metaanalysis

BACKGROUND Acute kidney injury(AKI)is a common and severe complication after left ventricular assist device(LVAD)implantation with an incidence of 37%;13%of which require kidney replacement therapy(KRT).Severe AKI requiring KRT(AKI-KRT)in LVAD patients is associated with high short and long-term mortality compared with AKI without KRT.While kidney function recovery is associated with better outcomes,its incidence is unclear among LVAD patients with severe AKI requiring KRT.AIM To identify studies evaluating the recovery rates from severe AKI-KRT after LVAD placement,which is defined by regained kidney function resulting in the discontinuation of KRT.Random-effects and generic inverse variance method of DerSimonian-Laird were used to combine the effect estimates obtained from individual studies.METHODS A total of 268 patients from 14 cohort studies that reported severe AKI-KRT after LVAD were included.Follow-up time ranged anywhere from two weeks of LVAD implantation to 12 mo.Kidney recovery occurred in 78%of enrollees at the time of hospital discharge or within 30 d.Overall,the pooled estimated AKI recovery rate among patients with severe AKI-KRT was 50.5%(95%CI:34.0%-67.0%)at 12 mo follow up.Majority(85%)of patients used continuous-flow LVAD.While the data on pulsatile-flow LVAD was limited,subgroup analysis of continuous-flow LVAD demonstrated that pooled estimated AKI recovery rate among patients with severe AKI-KRT was 52.1%(95%CI:36.8%-67.0%).Metaregression analysis did not show a significant association between study year and AKI recovery rate(P=0.08).There was no publication bias as assessed by the funnel plot and Egger's regression asymmetry test in all analyses.RESULTS A total of 268 patients from 14 cohort studies that reported severe AKI-KRT after LVAD were included.Follow-up time ranged anywhere from two weeks of LVAD implantation to 12 mo.Kidney recovery occurred in 78%of enrollees at the time of hospital discharge or within 30 d.Overall,the pooled estimated AKI recovery rate among patients with severe AKI-KRT was 50.5%(95%CI:34.0%-67.0%)at 12 mo follow up.Majority(85%)of patients used continuous-flow LVAD.While the data on pulsatile-flow LVAD was limited,subgroup analysis of continuous-flow LVAD demonstrated that pooled estimated AKI recovery rate among patients with severe AKI-KRT was 52.1%(95%CI:36.8%-67.0%).Metaregression analysis did not show a significant association between study year and AKI recovery rate(P=0.08).There was no publication bias as assessed by the funnel plot and Egger's regression asymmetry test in all analyses.CONCLUSION Recovery from severe AKI-KRT after LVAD occurs approximately 50.5%,and it has not significantly changed over the years despite advances in medicine.

Human Amniotic Membrane Promotes Antimicrobial Microenvironment in a Device-Related Infection

Hospital inquired post-operative infections are a leading cause of morbidity and mortality in patients receiving left ventricular assist devices. We present the case of a patient who acquired Candida albicans and Staphylococci infections following left ventricular assist device implantation. Use of standard antibiotics caused the infection to worsen, thus an amniotic membrane patch was used as a last-resort treatment. Within 6 weeks of the amniotic membrane patch treatment, the infection resolved, the wound appeared exceptionally clean upon inspection, and granulation tissue was present. After the infection resolved, a successful latissimusdorsi tissue flap procedure was completed and the patient made a full recovery.

Perioperative Nursing Management of an Animal Model of Axial Flow Blood Pump Implantation

This study aimed to explore the characteristics of perioperative nursing of experimental goats using self-made axial-flow blood pump implantation and provided theoretical nursing knowledge and practice-based evidence for the clinical application of domestically manufactured artificial cardiac pumps. Methods: Seven experimental goats were used in this study, three for pre-testing and four for the formal experiments. According to the surgical requirements for axial-flow blood pump implantation into the cardiac apex, we creatively designed and made a series of highly practical animal surgical instruments including a composite disassemblable bed for experimental animal transferring and monitoring, a multifunctional animal surgery bed, and portable medical supporting equipment. We also applied for two national invention patents and one utility model patent. Active measures were taken to ensure careful preparation before surgery, close collaboration during surgery, and effective management of complications after surgery. Results: Two of the four experimental goats died during surgery because of a massive hemorrhage caused by distal anastomotic failure and air embolism-induced cardiac arrest caused by air leakage from the outlet into the heart due to poor connection of the auxiliary pressure tap (used to measure left ventricular pressure). The mean survival time of the remaining three experimental goats was 22.7 hours. Conclusion: This study was the first to systematically and comprehensively investigate the perioperative nursing management of axial-flow blood pump implantation using animal models. These findings could greatly promote further clinical applied nursing research of self-made artificial cardiac pump implantation in experimental goats.

Anesthesia management of a patient undergoing implantation of a left ventricular assist system:A case report

BACKGROUND Heart failure is generally regarded as a progressive and irreversible medical condition.The EVAHEART is an implantable left ventricular assist system.CASE SUMMARY We report the anesthesia management of a 56-year-old male patient with dilated cardiomyopathy undergoing an EVAHEART implantation.Transesophageal echocardiography is crucial to ensure the correct positioning of the device and the proper aortic valve outflow.Because the continuous blood flow device functions best under low systemic and pulmonary vascular resistance,milrinone is the preferred drug.Our patient was accompanied by pulmonary hypertension,so during the operation,nitric oxide was used to reduce pulmonary artery pressure.CONCLUSION The cardiac output achieved by the patient with the assistance of EVAHEART can reach 4 L/min,which of course depends on the front load,rear load,and pump speed.