A comparative study of polyethylene oxide (PEO) using different coarse-graining methods.

Polyethylene oxide (PEO) holds significant importance in the field of batteries due to its high processability, intrinsic properties, and potential for high ionic conductivity. Achieving simulation at different scales is crucial for gaining a comprehensive understanding of its properties and thus improving them. In this context, we conducted a comparative study on the molecular physical structure, thermodynamic, and dynamic properties of PEO using three distinct coarse-grained (CG) procedures and all-atom (AA) simulations. The three CG simulation procedures involved modeling with MARTINI forcefield, SPICA forcefield, and an IBI derived potential from AA simulations. The AA simulation has been performed using the class 2 pcff+ forcefield. The ensuing simulated densities align significantly with the literature data, indicating the reliability of our approach. The solubility parameter from the AA simulation closely corresponds to literature reported values. MARTINI and SPICA yield almost similar solubility parameters, consistent with the similar density predicted by both the forcefields. Notably, SPICA forcefield closely reproduces the intermolecular structure of atomistic systems, as evidenced by radial distribution function (RDF). It also comprehensively replicates the distribution of radius of gyration (Rg) and the end-to-end distance (Re) of the atomistic samples. IBI ranks second to SPICA in emulating the structural properties of the atomistic systems, such as Rg, Re, and RDF. However, IBI falls short in accurately representing the solubility parameter of the amorphous PEO samples, while MARTINI does not provide an accurate representation of the structural properties of the systems. The use of SPICA forcefield results in enhanced dynamics of the systems in comparison with IBI and MARTINI.

Host-Bacterium Interaction Mechanisms in Staphylococcus aureus Endocarditis: A Systematic Review.

Staphylococci sp. are the most commonly associated pathogens in infective endocarditis, especially within high-income nations. This along with the increasing burden of healthcare, aging populations, and the protracted infection courses, contribute to a significant challenge for healthcare systems. A systematic review was conducted using relevant search criteria from PubMed, Ovid's version of MEDLINE, and EMBASE, and data were tabulated from randomized controlled trials (RCT), observational cohort studies, meta-analysis, and basic research articles. The review was registered with the OSF register of systematic reviews and followed the PRISMA reporting guidelines. Thirty-five studies met the inclusion criteria and were included in the final systematic review. The role of Staphylococcus aureus and its interaction with the protective shield and host protection functions was identified and highlighted in several studies. The interaction between infective endocarditis pathogens, vascular endothelium, and blood constituents was also explored, giving rise to the potential use of antiplatelets as preventative and/or curative agents. Several factors allow Staphylococcus aureus infections to proliferate within the host with numerous promoting and perpetuating agents. The complex interaction with the hosts' innate immunity also potentiates its virulence. The goal of this study is to attain a better understanding on the molecular pathways involved in infective endocarditis supported by S. aureus and whether therapeutic avenues for the prevention and treatment of IE can be obtained. The use of antibiotic-treated allogeneic tissues have marked antibacterial action, thereby becoming the ideal substitute in native and prosthetic valvular infections. However, the development of effective vaccines against S. aureus still requires in-depth studies.

The Roles of microRNAs in the Cardiovascular System.

The discovery of miRNAs and their role in disease represent a significant breakthrough that has stimulated and propelled research on miRNAs as targets for diagnosis and therapy. Cardiovascular disease is an area where the restrictions of early diagnosis and conventional pharmacotherapy are evident and deserve attention. Therefore, miRNA-based drugs have significant potential for development. Research and its application can make considerable progress, as seen in preclinical and clinical trials. The use of miRNAs is still experimental but has a promising role in diagnosing and predicting a variety of acute coronary syndrome presentations. Its use, either alone or in combination with currently available biomarkers, might be adopted soon, particularly if there is diagnostic ambiguity. In this review, we examine the current understanding of miRNAs as possible targets for diagnosis and treatment in the cardiovascular system. We report on recent advances in recognising and characterising miRNAs with a focus on clinical translation. The latest challenges and perspectives towards clinical application are discussed.

Impact of application of queuing theory on operational efficiency of patient registration.

Background: Hospital administrators are often challenged with overcrowding at hospitals. The study hospital receives referred patients; however, they have to wait in long queues even for getting registered. This was a cause of concern for hospital administrators. The study was undertaken to find an amicable solution to the queues at registration using Queuing Theory. Method: This observational and interventional study was carried out in a tertiary care ophthalmic hospital. In the first phase, data of service time and arrival rate was collected. The queuing model was built using the coefficient of variation (CoV) of the observed times. Server utilization for new patient registration was found to be 1.21 and was 0.63 for revisit patients. Scenario-based simulation carried out using free software for optimal utilization of both types of servers. Recommendations made to combine the registration process and to increase one server were implemented.In the second phase, after one year, patient registration data were collected and compared for the number of patients registered using SPSS 17. Results: Number of patients registered within the registration timings increased whereas the number of patients registered after the registration timings decreased significantly at 95% CI with a p-value of less than 0.001. Queues finished early and more number of patients were registered in the same time. Conclusion: Using queuing theory, the bottleneck of the systems can be identified. Scenario and software-based simulations provide solutions to the problem of queues. The study is an application of Queuing Theory with a focus on efficient resource utilization. It can be replicated in an organization with limited resources facing the challenge of queues.

Learning from Controversy and Revisiting the Randomized Trials of Secondary Mitral Regurgitation.

Until recently, conventional mitral valve surgery has been the treatment of choice even in secondary mitral regurgitation. Recent evidence, however, advocates the use of transcatheter edge-to-edge mitral valve repair (TEER) of the mitral valve. This has been reflected by the change in guidelines of the American College of Cardiology/American Heart Association. We reviewed the literature to shed light on the risks and benefits of all interventions, surgical, transcatheter and guideline-directed medical therapy. Secondary mitral regurgitation occurs due to an imbalance between closing forces and tethering forces. Given the pathology extends beyond the valve alone, treatment should be directed at restoring the geometrical shape of the left ventricle alongside the valve. Myocardial revascularization plays a pivotal role in preventing recurrence. The role of papillary muscle approximation in addition to restrictive mitral annuloplasty should be considered in a select group of patients. We also reviewed the current literature on TEERs from the COAPT and Mitra-FR trials while highlighting the concept of proportionate/disproportionate MR which may help identify which patients benefit from mitral valve restoration. Treatment of this condition will require robust randomized trials alongside the use of state-of-the-art imaging technologies available with the full complement of the multidisciplinary team to ensure the best outcomes for each patient.

Postinflammatory rupture of right coronary artery ostium complicating Behçet disease.

INTRODUCTION: Behçet disease (BD) is a chronic relapsing inflammatory disease of unknown etiology, characterized by variable clinical manifestations. METHODS: A 28-year-old woman with BD Cardiovascular and Bipolar Disorder underwent emergency surgical treatment of ascending aortic pseudoaneurysm for ruptured right coronary ostium.A modified Bentall procedure with tricuspid annuloplasty, surgical thrombectomy, and a single coronary artery bypass using a saphenous vein graft was performed. A biological prosthesis was used initially but subsequently deteriorated. We then successfully performed a valve-in-valve (ViV) transcatheter aortic valve implantation (TAVI). RESULTS: The postoperative recovery was uneventful and at follow-up, two years post valve procedure, the patient was completely symptom-free. She remains under long-term medical surveillance. CONCLUSION: The management of BD with cardiac involvement must be led by a multidisciplinary team.

Allocation scheduling leads to optimum utilization of operation theater time.

Background: Cancellation of surgeries is a regular phenomenon in any hospital, and reasons may vary from clinical to managerial ones. The aim of the study is to suggest scheduling to address the problem of time over run related cancellations. This is an observational and descriptive study conducted in a tertiary care hospital with ophthalmology facilities. The sample size is calculated with 95% confidence interval using Epi Info 6 from the total surgeries performed in the last 5 years (n = 380). Simple random sampling technique was used. Methods: Surgical time for all types of ophthalmic surgeries (n = 582) was observed. Allocation of listed cases to the available operating rooms (ORs) was carried out using the observed time using LEKIN software. Results: The time over-run of 2 h and 6 h was noted for two units, whereas idle OR time was observed in other units. An average idle time of 19% was noted on each day. Reallocation of the cases to the ORs was carried out taking all the planned cases (of both the operating units of the day) as the number of jobs and all the available ORs as parallel machines using LEKIN software. All the planned cases could be accommodated; still, an average of 17% of the total available operation theater (OT) time was found idle on each day. Conclusions: Planning of cases using procedure time and scheduling on a daily basis using allocation models with simple algorithms can provide optimal utilization of OTs and can address the time over-run and related cancellations.

The antegrade reperfusion test avoids the risk of mitral regurgitation recurrence optimizing valve repair.

Saline injection into the left ventricle trough mitral valve (saline test) is the most commonly used intraoperative assessment method in mitral valve repair. However, potential discrepancies between the saline test findings and intraoperative transesophageal echocardiography results after the weaning of cardiopulmonary by-pass, remain significant. Here, we describe a new antegrade reperfusion test, reproducing intraoperatively, the physiologic conditions of loaded and beating heart for direct transatrial evaluation of valve tightness. The proposed test is performed by perfusing warm oxygenated blood into the aortic root under cross-clamping. From February 2016 to December 2018, 91 patients (mean age: 63 ± 11 years) underwent mitral valve repair for mitral regurgitation. In all of them, the classic saline test was completed with the newly proposed antegrade test. We report our results with this combined approach. Data were obtained from the medical records and our mitral valve repair database. In 32 (35.1%) patients, evident or undetectable minor regurgitation at the saline test were respectively unconfirmed or detected by the antegrade reperfusion test leading to their complete correction. In only three patients (3.2%) major discrepancies was present between the intraoperative evaluation and the post-pump transesophageal echocardiography. Two of them (2.1%) required a second cardiopulmonary bypass run to fix the residual regurgitation. The antegrade reperfusion test is a simple dynamic intraoperative approach mimicking the physiological conditions of ventricular systole for mitral valve repair evaluation. Combined with the classic saline test, it seems to be a valuable additional intraoperative tool, enabling a more predictable repair result.

MicroRNAs in Valvular Heart Diseases: Biological Regulators, Prognostic Markers and Therapeutical Targets.

miRNAs have recently attracted investigators' interest as regulators of valvular diseases pathogenesis, diagnostic biomarkers, and therapeutical targets. Evidence from in-vivo and in-vitro studies demonstrated stimulatory or inhibitory roles in mitral valve prolapse development, aortic leaflet fusion, and calcification pathways, specifically osteoblastic differentiation and transcription factors modulation. Tissue expression assessment and comparison between physiological and pathological phenotypes of different disease entities, including mitral valve prolapse and mitral chordae tendineae rupture, emerged as the best strategies to address miRNAs over or under-representation and thus, their impact on pathogeneses. In this review, we discuss the fundamental intra- and intercellular signals regulated by miRNAs leading to defects in mitral and aortic valves, congenital heart diseases, and the possible therapeutic strategies targeting them. These miRNAs inhibitors are comprised of antisense oligonucleotides and sponge vectors. The miRNA mimics, miRNA expression vectors, and small molecules are instead possible practical strategies to increase specific miRNA activity. Advantages and technical limitations of these new drugs, including instability and complex pharmacokinetics, are also presented. Novel delivery strategies, such as nanoparticles and liposomes, are described to improve knowledge on future personalized treatment directions.

Ross operation 23 years after surgery: It should not be a "forgotten" option.

INTRODUCTION: The Ross procedure plays a pivotal part in both congenital and acquired diseases of the aortic valve, especially in young patients. The advantages of this procedure are widely known; however, long-term studies have shown dilation of the pulmonary autograft (PA) in up to 20% of patients in the second decade postoperatively. METHODS: Three cases (ages 38, 51, and 53) who underwent the Ross procedure 23 years ago for bicuspid valves and endocarditis. Cases were followed-up with echocardiogram and computed tomography scan with three-dimensional reconstructions. RESULTS: The PA showed normal function with favorable geometry alongside the thoracic aorta, while the pulmonary homograft preserved its function with a low degree of calcification. The mean annual expansion of the autograft was only 0.15, 0.30, and 0.40 mm with no pathological dilation after 20 years DISCUSSION: Ross operation provides excellent hemodynamic results while avoiding long-term anticoagulation and might constitute a valid adjunct in selected categories such as young or endocarditis patients.

Heart Valve Endocarditis.

Heart valve replacement is the most common cardiac surgical operation performed worldwide for infective endocarditis (IE). Long-term durability and avoidance of infection relapse are the goals of the procedure. However, no detailed guidelines on prosthesis selection and surgical strategies are available, which should be guided by a comprehensive evaluation of the extent of the infection and its microbiological characteristics, the clinical profile of the patient and the risk of infection recurrence. Conventional mechanical or stented xenografts are the preferred choice for localized heart infection. In cases of complex IE with involvement of the root or the aorto-mitral continuity, the use of homograft is suggested according to the surgeon's and center's experience. The use of homograft needs to be balanced against the risk of structural degeneration. Prosthetic bioroot and prosthetic valved conduit with a mechanical or bioprosthetic valve are also considered acceptable alternatives in patients with aortic valve endocarditis. The further development of preservation techniques to enable the longer durability of allogeneic substitutes is required. We discuss current evidence for the use of valve substitutes in heart valve endocarditis and propose an evidence-based algorithm for the choice of treatment.

PREDICTA: A Model to Predict Primary Graft Dysfunction After Adult Heart Transplantation in the United Kingdom.

BACKGROUND: Primary graft dysfunction (PGD) is a major cause of morbidity and mortality post-heart transplantation. The rates of PGD across Europe are higher than North America possibly because of the increasing use of extended criteria donors because of organ shortage. Our aim was to derive a novel scoring system based on data collected nationally in the UK over a 3-year period. We compared this scoring system to a previously validated (RADIAL) score in a contemporary cohort of patients. METHODS: Medical records of all adult patients who underwent heart transplantation between October 1, 2012 and September 30, 2016 in the 6 UK heart transplant centers were analyzed. Preoperative donor and recipient characteristics, intraoperative details and post-transplant complications were compared between the PGD and non-PGD groups using the International Society of Heart and Lung Transplant definition. Multivariable logistic regression was used to build the predictive model. An area under receiver operating characteristics curve was used to test the novel scoring system (PREDICTA) versus the RADIAL score. RESULTS: Six hundred and thirteen heart transplants were included in the study. There were 233 patients who had PGD. The variables included in the model were recipient diabetes mellitus, preoperative mechanical circulatory support (short-term ventricular assist devices/extracorporeal membrane oxygenation), implant time, donor age, and bypass time >180 minutes. The C statistic of the PREDICTA score was 0.704 versus 0.547 for the RADIAL score indicating an acceptable discriminatory value. CONCLUSION: The PREDICTA score is a novel scoring tool with improved ability to predict the development of PGD compared with the RADIAL score. Its application in the prevention and early management of PGD needs further evaluation.

Primary graft dysfunction after heart transplantation: a thorn amongst the roses.

Primary graft dysfunction (PGD) remains the leading cause of early mortality post-heart transplantation. Despite improvements in mechanical circulatory support and critical care measures, the rate of PGD remains significant. A recent consensus statement by the International Society of Heart and Lung Transplantation (ISHLT) has formulated a definition for PGD. Five years on, we look at current concepts and future directions of PGD in the current era of transplantation.

The Radial Artery for Coronary Bypass Grafting: The Fifth Decade.

BACKGROUND: In 1989, we reported the use of the radial artery as a second target conduit for coronary artery bypass grafting. However, underpowered randomized trials have reported differences in clinical outcomes between the radial artery and other grafts. As we approach 50 years of experience with radial artery grafting, we reviewed the literature to determine the second-best target vessel for coronary operations. METHODS: An electronic review of the literature with an emphasis on randomized controlled trials, propensity-matched observational series, and meta-analyses identified a large population of patients who received arterial conduit and saphenous vein grafts. RESULTS: The radial artery has been proven to be reliable as a second target conduit for coronary artery bypass grafting, with outcomes and patency rates superior to those for saphenous vein graft. It has also been proven to be both safe and effective as a third conduit in the territory of the right coronary artery. A paucity of evidence with few comparable series limits the use of the gastroepiploic artery. CONCLUSION: In its fifth decade of use, we can definitively conclude that the aorto-to-coronary radial bypass graft is the conduit of choice for coronary operations after the left internal thoracic artery to the left anterior descending artery.

Transcatheter Tricuspid Valve Interventions: Current Approaches and Future Perspectives.

Tricuspid valve regurgitation is generally functional in nature due to right-sided dysfunction in the setting of left-sided concomitant cardiac disease or pulmonary hypertension. Patients living with tricuspid regurgitation often experience numerous limitations as a result of right-sided heart failure symptoms. Patients with significant tricuspid disease, whether native, repaired, or replaced valve, often present with significant symptoms but may not be ideal candidates for operation or, eventually, reoperation. Transcatheter techniques to either repair or replace the tricuspid valve are a burgeoning frontier in structural cardiac interventions. Anatomical challenges include the large and asymmetrical annulus, paucity of calcification, adjacency of the right coronary artery system, and fragility of the valve tissue. Current approaches under investigation in feasibility and early phase clinical trials include edge-to-edge repair, coaptation enhancement, annuloplasty, heterotopic caval valve implantation, and percutaneous tricuspid valve replacement. Although there are limitations to the currently available transcatheter options for the patients, the initial data demonstrate the relative safety of using existing devices with good results and functional improvement. Hopefully, the emerging interest into interventional therapy of tricuspid valve disease will bring back the "forgotten valve" into the conscience of the cardiological and surgical community. This review intends to summarize the current strategies and evidences in transcatheter tricuspid valve intervention and enlightening new avenues for future clinical studies.

Urodynamic Changes after Valve Fulguration Alone and Valve Fulguration with Bladder Neck Incision.

AIMS: The aim of this study is to compare urodynamic changes after valve fulguration alone and valve fulguration with bladder neck incision (BNI). SETTINGS AND DESIGN: A total of 81 patients with posterior urethral valve were treated at our center from July 2010 to July 2016. Patients were randomized into two groups using simple randomization. Forty patients underwent BNI in addition to valve fulguration (Group I), and the remaining 41 patients underwent conventional transurethral valve fulguration (Group II). SUBJECTS AND METHODS: The exclusion criteria for both the groups were the presence of simultaneous urogenital anomalies, any neurological condition, history of any urethral manipulation, and urinary diversion. Urodynamic changes were compared in both groups postoperatively. All patients were evaluated throughout their follow-up, according to the following protocol: (a) Voiding cystourethrography at 6 weeks after surgery; (b) Renal function test and urine culture at 6 weeks and then 3 monthly; (c) Ultrasound kidney, ureter, and bladder region and urodynamics at 3 and 6 months after surgery and then yearly. Median follow-up period for Group I was 27.5 months (13-72 months) and 14 months (14.5-72 months) for Group II. STATISTICAL ANALYSIS USED: Statistical analysis was done using the Student's t-test for parametric data and Chi-square test for categorical variable. P ≤ 0.05 was considered as statistically significant. RESULTS: The mean age was 7.26 years in Group I and 7.66 years in Group II at the end of follow-up. There was no statistically significant difference found regarding detrusor overactivity (P = 0.68), compliance (P = 0.052), end-filling pressure (P = 0.08), and max Pdet at Qmax (P = 0.08) in the both groups. However, there was a statistically significant difference regarding improvement of peak flow (P = 0.038) and postvoid residue (PVR) (P = 0.045) in Group I in comparison to Group II. CONCLUSIONS: Valve ablation with BNI gives statistically significant better urodynamics in voiding phase regarding flow and lesser PVR in comparison to valve ablation.

Simulation as a preoperative planning approach in advanced heart failure patients. A retrospective clinical analysis.

BACKGROUND: Modelling and simulation may become clinically applicable tools for detailed evaluation of the cardiovascular system and clinical decision-making to guide therapeutic intervention. Models based on pressure-volume relationship and zero-dimensional representation of the cardiovascular system may be a suitable choice given their simplicity and versatility. This approach has great potential for application in heart failure where the impact of left ventricular assist devices has played a significant role as a bridge to transplant and more recently as a long-term solution for non eligible candidates. RESULTS: We sought to investigate the value of simulation in the context of three heart failure patients with a view to predict or guide further management. CARDIOSIM© was the software used for this purpose. The study was based on retrospective analysis of haemodynamic data previously discussed at a multidisciplinary meeting. The outcome of the simulations addressed the value of a more quantitative approach in the clinical decision process. CONCLUSIONS: Although previous experience, co-morbidities and the risk of potentially fatal complications play a role in clinical decision-making, patient-specific modelling may become a daily approach for selection and optimisation of device-based treatment for heart failure patients. Willingness to adopt this integrated approach may be the key to further progress.

Transcatheter Technologies for Valvular Replacement: an Update.

This report provides a brief overview of the basic principles, recent advances, and recommendations for the treatment of severe aortic stenosis with transcatheter aortic valve replacement (TAVR) in adults. Approaches that avoid neurological, cardiac and peripheral vascular complications have been developed. In addition, TAVR can be performed in intermediate- and low-risk patients. However, these procedures require specialized training and may not allow for complete resolution of the underlying issue. Even if cardiologists learn to perform the procedure and despite advancements in device technology, TAVR is still susceptible to structural valve degeneration, thrombosis and late cerebral embolization. To date, TAVR has shown no consistent advantage over surgical aortic valve replacement (SAVR) in intermediate- and low-risk patients.

A prospective randomized study comparing the four tract dilation methods of percutaneous nephrolithotomy.

OBJECTIVE: To compare the one-shot dilation (OSD) technique with three other dilation techniques namely telescopic Alken, fascial Amplatz and balloon dilation (BD) in terms of safety efficacy and cost effectiveness. METHODS: During a 3½ year enrollment period, 480 patients who required PCNL surgery were equally randomized into four groups. All the cases were assessed preoperatively, intraoperatively as well as postoperatively till a period of 3 months. Access time, X-ray exposure time, hemoglobin drop, complications, success rate, etc., were all assessed and recorded. RESULTS: Similar preoperative characteristics were observed in all the four study arms. X-ray exposure time during dilation was significantly reduced for both OSD and BD when compared to sequential Amplatz and telescopic Alken dilation (Group ALD = 62.1 + 13, Group AMD = 67.0 + 10, Group OSD = 36.8 + 7, Group BD = 38.1 + 6, p value = 0.01, post hoc: G4 = G3 < G2 = G1). There was no significant difference between the access time, hemoglobin drop, complication and success rates among the groups. BD was the most expensive dilation method when compared to the other three dilation techniques. CONCLUSION: All the four methods of dilation are equally safe and effective but both OSD and BD are advantageous in terms of lesser fluoroscopy time during dilation. OSD is much cheaper option when compared to BD, and therefore with more experience, it can become the preferable dilation method, especially in the developing countries.

Follow-up imaging after pediatric pyeloplasty.

INTRODUCTION: The duration, methods and frequency of radiographic follow-up after pediatric pyeloplasty is not well-defined. We prospectively evaluated a cohort of children undergoing pyeloplasty to determine the method for follow-up. METHODS: Between 2000 and 2008, children undergoing pyeloplasty for unilateral ureteropelvic junction obstruction were evaluated for this study. All patients were evaluated preoperatively with protocol ultrasound (USG) and diuretic renal scan (RS). On the basis of preoperative split renal function (SRF), these patients were divided into four groups - Group I: SRF > 40%, Group II: SRF 30-39%, Group III: SRF 20-29%, and Group IV: SRF 10-19%. In follow-up, USG and RS were done at 3 months and repeated at 6 months, 1 year, and then yearly after surgery for a minimum period of 5 years. Improvement, stability, or worsening of hydronephrosis was based on the changes in anteroposterior (AP) diameter of pelvis and caliectasis on USG. Absolute increase in split renal function (SRF) >5% was considered significant. Failure was defined as increase in AP diameter of pelvis and decrease in cortical thickness on 3 consecutive USG, t½ >20 min with obstructive drainage on RS and/or symptomatic patient. RESULTS: 145 children were included in the study. Their mean age was 3.26 years and mean follow-up was 7.5 years. Pre- and post-operative SRF remain unchanged within 5% range in 35 of 41 patients (85%) in Group I. While 9 of 20 patients (45%) in Group II, 23 of 50 patients (46%) in Group III, and 14 of 34 patients (41%) in Group IV exhibited changes >5% after surgery. 5 patients failed, 2 in Group III, and 3 in Group IV. None of the patients deteriorated in Group I and II. CONCLUSION: After pyeloplasty in children with a baseline split GFR >30%, if a diuretic renogram and USG performed 3 months postoperatively shows nonobstructive drainage with t½ <20 min and decreased hydronephrosis, no further follow-up is required.