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In this article, the authors focus on diophantine equations. They relate that diophantine equations constitute a rich mathematical field and that their study can be useful for a student math club project. They say that there is a need to find solution for indeterminate polynomial equations that allow the variables to be integers only. They use the classical tiling of a plane with three regular convex polygons to introduce the problem they presented.

A simple solution of the problem of inviscid flow past two circular cylinders is presented. The two cylinders may be of different diameters and located at any distance from each other The solutions of the two main cases, namely, when the flow is perpendicular to the center-to-center line and when the flow is parallel to it (tandem cylinders), lead to a solution of the problem when the flow is in an arbitrary direction. [ABSTRACT FROM AUTHOR]

Abstract: The phenomenon of secondary motion (acoustic streaming) created by the oscillation of a fluid past a sphere is investigated through numerically solving the full Navier–Stokes equations. The main parameters that affect the structure of acoustic streaming are Reynolds number and Strouhal number. The results are presented in the form of steady streaming patterns as well as the relation between Reynolds and Strouhal numbers and the dimensions of the streaming region. [Copyright &y& Elsevier]

Abstract   A new result for integrals involving the product of Bessel functions and Associated Laguerre polynomials is obtained in terms of the hypergeometric function. Some special cases of the general integral lead to interesting finite and infinite series representations of hypergeometric functions. [ABSTRACT FROM AUTHOR]

During the course of teaching parametric equations to calculus students, the parametric equations of a point attached rigidly at a distance from the center of a circle rolling on the outside of a fixed ellipse were derived. These equations and several graphs including the prolate and curtate cases are presented in this paper. [ABSTRACT FROM AUTHOR]

The discrete counterpart of a class of Hopfield neural networks with periodic impulses and finite distributed delays is introduced. A sufficient condition for the existence and global exponential stability of a unique periodic solution of the discrete system considered is obtained. [ABSTRACT FROM AUTHOR]

Forced convection past a heated oblate spheroid is studied in an attempt to investigate the effect of the axis ratio on the heat transfer rate. The time-dependent full Navier-Stokes and energy equations are solved using a series truncation method. The axis ratios considered range from ½ to 1 (a perfect sphere). The results for the flow and thermal fields are satisfactorily compared with relevant published research. The results are presented in the form of streamlines, isotherms, and the local and averaged Nusselt number distributions. [ABSTRACT FROM AUTHOR]

We investigate the global stability characteristics of a system of equations modelling the dynamics of additive Hopfield-type neural networks with impulses in the continuous-time case. [Copyright &y& Elsevier]

The problem of viscous flow over a sphere with fluctuations in the free-stream velocity is considered. The governing conservation equations are expressed terms of the stream function and vorticity and solved using the series truncation method where the stream function and vorticity are approximated using finite series of Legendre and first associated Legendre functions. The effects of the Reynolds number, Strouhal number, and the amplitude of the fluctuations on the flow characteristics are studied. Results are presented for periodic variation of the drag coefficient, surface vorticity and pressure distributions for Reynolds numbers ranging from 5 to 100, Strouhal numbers ranging from π/4 to π, and amplitude of fluctuations from 0.0 to 0.5. The time variation of the velocity field during one complete cycle is presented in the form of streamline and equi-vorticity patterns. The periodic variation of the angle of separation as well as the length of the separation region are also presented. [ABSTRACT FROM AUTHOR]

This paper deals with the problem of oscillating viscous flow over an oblate spheriod. The flow is assumed incompressible and axisymmetric and the motion is governed by the Navier-Stokes equations. The method of solution is based on the series truncation method where the stream function and vorticity are expressed in terms of a finite series of Legendre functions. The effects of the Reynolds and Strouhal numbers on the flow characteristics are studied and compared with previous available solitions. Results are presented for the periodic variation of the drag coeffficient, surface vorticity and pressure distributions for Reynolds numbers ranging from 5 to 100 and Strouhal numbers ranging from π/4 to while keeping the spheroid axis ratio unchanged. The time variation of the velocity field during one complete oscillation is presented in the form of streamline and equi-vorticity patterns. The periodic variation of the angle of separation as well as the length of the separation bubble are also presented. The double boundary layer structure previously observed in the case of a sphere is also detected. [ABSTRACT FROM AUTHOR]

The problem of the impulsively started flow over an oblate spheroid is solved using the series truncation method in which the stream function and vorticity are expanded in terms of series of Legendre functions. The resulting time-dependent differential equations are solved using the Crank-Nicolson finite difference scheme. The parameters involved are the Reynolds number and the axis ratio. The range of Reynolds numbers considered is from 5 to 100 while the axis ratio is considered at values of A r = 0.6 and 0.76. The time variation of the flow field is presented in the form of streamline and equi-vorticity patterns as well as pressure and surface vorticity distributions. The time development of the separation angle, wake length, and the frictional and total drag coefficients are also presented. The large time (steady) values of the drag coefficient for the special case of a sphere are compared with previously known data and the agreement is satisfactory. [ABSTRACT FROM AUTHOR]

The problem of uniform steady viscous flow over an oblate spheroid is solved in the low-Reynolds-number range 0.1 ≤ Re ≤ 1.0. The full Navier-Stokes equations are written in the stream function-vorticity form and solved numerically by means of the series-truncation method. Spheroids having axis ratio ranging from 0.245 to 0.905 are considered. The obtained drag coefficients are compared with previous analytical formulae which were based on the solution of the linearized Stokes equations. As expected, the deviation between the present results and the analytical formulae is small for low-Re flows, however, it increases with the increase of Re. The present results provide a measure for establishing the range of validity of the analytical solutions. [ABSTRACT FROM AUTHOR]

• Steady-state solution of the flow in anisotropic porous media between two cylinders is given as a sum of infinite series. • The analysis shows that the anisotropy and ratio between two radii of inner and outer cylinder have a significant impact on the pressure distribution. • The modified approach for the experimental procedure utilizes the proposed solution to determine the anisotropy parameters in the lab from the holed core experiment. Anisotropy is a common feature for most of fibrous and porous media. This article reports a new method for measuring the 2D anisotropic permeability of a porous rock utilizing the measurements obtained from the steady-state flow between two concentric cylinders. The mathematical analysis of the experimental data is based on the general solution of the pressure equation derived for the steady-state flow equation for an anisotropic porous medium between two concentric cylinders. The general solution, incorporating the degree of anisotropy and the ratio between inner and outer cylinder radii, is presented in a dimensionless form. The solution shows that pressure distribution between the two cylinders is composed of an isotropic part plus a series representing the contribution of the anisotropy. The solution is validated through the comparison against numerically derived results and the analytical solution of two extreme cases; when the clearance between the two cylinders vanishes, and when the material is isotropic. The validation shows a perfect performance of the proposed solution even in the vicinity of the inner cylinder not like the approximate solutions existing in the literature. The validation also shows that the truncation of the series part has an impact on the results specially in the case of extreme anisotropy. Two experimental procedures 1) basic approach and 2) modified approach, utilizing the "pear" and "tent" charts derived from the general solution, demonstrate how to obtain the principle permeabilities and their directions. The applicability of the proposed experimental techniques is attained through the application of the modified approach over real experimental data from a holed core experiment to estimate anisotropic permeability parameters. The application of the proposed technique and the required modifications for measuring the anisotropy in tight cores are discussed. Also, the relation between the three-dimension anisotropy and the presented plane anisotropy is presented. [ABSTRACT FROM AUTHOR]

The incidence of atrial fibrillation increases with age, and therefore many elderly patients presenting for cardiac surgery have atrial fibrillation. In recent publications, increasing age has been recognized as a predictor for ablation failure. Furthermore, many surgeons are reluctant to perform a surgical ablation in elderly patients. We investigated the safety and efficacy of concomitant surgical atrial fibrillation ablation in elderly patients. Between 2003 and 2013, 556 patients underwent concomitant surgical atrial fibrillation ablation at the University Heart Center Hamburg and served as our primary study cohort. During follow-up, rhythm monitoring was established by 24-hour Holter electrocardiogram (70.5%) or an implantable loop recorder (29.5%) at 3, 6, and 12 months postoperatively. The primary end point of the study was freedom from atrial fibrillation at 12 months follow-up and the detection of deviations from a linear association between age and risk of atrial fibrillation recurrence. A multiple logistic regression model including age as a linear term was used to identify predictors for rhythm outcome. Mean patients' age was 68.4 ± 9.07 years, and 67.3% of the patients were male. Mean duration of atrial fibrillation was 3.5 ± 3.3 years, and mean left atrium diameters were enlarged with 50.5 ± 8.8 mm. There were no major ablation-related complications. The 30-day and 1-year survivals were 97.7% and 95.8%, respectively. The overall rate of freedom from atrial fibrillation ranged from 62% to 72% and was independent of age. The age-dependent risk of atrial fibrillation at 12 months was significantly increased in elderly patients undergoing a concomitant coronary artery bypass grafting surgery. Multiple logistic regression model revealed double valve procedures (odds ratio, 3.48; P =.020), preoperative persistent atrial fibrillation (odds ratio, 2.43; P =.001), and coronary artery bypass grafting surgery in elderly patients (odds ratio, 2.03; P =.009) as risk factors for recurrence of atrial fibrillation. Sinus rhythm at discharge (odds ratio, 0.39; P <.001) and bipolar ablation (odds ratio, 0.32; P <.001) were significant predictors for successful ablation. Surgical atrial fibrillation ablation was safe and effective independently of age. Sinus rhythm at discharge and bipolar ablation were significant predictors for successful ablation, whereas double valve procedures, preoperative persistent atrial fibrillation, and coronary artery bypass grafting surgery in elderly patients were risk factors for recurrence of atrial fibrillation. [Display omitted] [ABSTRACT FROM AUTHOR]

Improvement in preservation and transportation conditions has the potential to enhance organ quality at the time of transplant, optimize patient outcomes, and prolong the acceptable maximum allograft ischemic time. Herein, we describe our initial successful experience with the static hypothermic preservation system (Paragonix) for a donor heart. Our storage period and allograft ischemic time are the longest reported in the literature. A 68-year-old woman with HF was listed for transplantation. A donor heart was procured from a hospital located 3.5 hours away. The donor allograft was secured and packaged using the SherpaPak™ device (Fig. 1) ; total storage period was 283 mins. Heart transplantation was performed in standard fashion. AV conduction and normal sinus rhythm were regained after 7 mins of reperfusion. Total ischemic time was 330 mins, including a warm ischemic time of 20 minutes. The recipient CPB time and aortic cross clamp time were 153 and 50 mins, respectively. The patient recovered well and was discharged on postoperative day 10. At three months post-transplant, the patient continues to have excellent graft function without any evidence of rejection. Historically, Shumway et al. initially obtained donor hearts from operating rooms immediately adjacent to a recipient. Over time, donor distance and allograft ischemic times have increased with advances in cardiac preservation. However, long cold ischemic times may induce PGD, cardiac allograft vasculopathy, and contribute to increased length of stay. Maintaining storage temperatures within the narrow range of 4-8°C is optimal for the preservation of high energy phosphate stores and avoids the risk of cold ischemic injury at temperatures below 2°C. By expanding geographic boundaries and total ischemic times, we believe that regulated static hypothermic preservation is a useful addition to a growing armamentarium of devices and strategies to increase access to transplantation. [ABSTRACT FROM AUTHOR]

Computer science has become one of the most important sciences that have an effective role in the various scientific fields, including the science of artificial intelligence, which works on simulating human behavior in different scientific fields. The most important of these fields is the field of medicine. Experience in diagnosis of diseases and treatment description and using this medical software and the development of the science of artificial intelligence on the development of medical devices. An example of AI is the pacemaker. Pacemaker Implantation is a surgical procedure in which an automated pacemaker is implanted by replacing the infected cells that regulate the heartbeat in the patient's heart. [1] For cells that specialize in the generation and transfer of the symbol regulating the heart rate, because of the loss of these cells for their performance or as a result of dysfunction. Natural organized cells do their job by sending electrical signals through the nerve fibers, resulting in a contraction of the muscle fibers of the heart, which leads to the heart's vital function of pumping blood across the body. [ABSTRACT FROM AUTHOR]

Background: Although acute kidney injury (AKI) has been established as an independent risk factor for in‐hospital mortality for patients on veno‐arterial (V‐A) extracorporeal membranous oxygenation (ECMO), the impact of Kidney Disease Improving Global Outcomes (KDIGO) stages of AKI has yet to be elucidated as a risk factor. Methods: We conducted a retrospective analysis of patient outcomes based on KDIGO stages of AKI at a single institution. The analysis was a cohort of 179 patients; 66 without AKI, 19 with stage 1 AKI, 18 with stage 2 AKI, and 76 with stage 3 AKI. Results: Every 1‐year increase in age was associated with 4% increased odds of mortality at 30 days (95% confidence interval [CI] 1.01, 1.07; p = 0.004). The presence of AKI at any stage was associated with 59% increased odds of 30‐day mortality (95% CI 0.81, 3.10; p = 0.176). The presence of stage 1 AKI was associated with a 5% decreased odds of 30‐day mortality (95% CI 0.32, 2.89). The presence of stage 2 AKI (odds ratio [OR] 2.29, 95% CI 0.69, 7.55; p = 0.173) and stage 3 AKI (OR 1.68, 95% CI 0.81, 3.46; p = 0.164) was associated with increased odds of 30‐day mortality. Conclusion: Based on our single‐center study, higher KDIGO stages of AKI likely have increased odds of mortality at 30 days. Larger studies are needed to confirm these findings. [ABSTRACT FROM AUTHOR]

Background Systemic inflammation due to cardiogenic shock is associated with vasoplegia leading to organ hypoperfusion, right heart failure, and poor clinical outcome. Extracorporeal cytokine hemoadsorption emerged to attenuate excessive levels of inflammatory cytokines, potentially improving patient outcomes. Nevertheless, its prognostic impact during high-risk left ventricular assist device (LVAD) implantation remains unknown. Methods In total, 40 consecutive patients with advanced heart failure underwent continuous-flow LVAD implantation at our institution between 2018 and 2020. Out of 25 high-risk patients in cardiogenic shock (Interagency Registry for Mechanically Assisted Circulatory Support profile 1 and 2), 9 patients (CytoSorb group) underwent LVAD implantation with and 16 patients (control group) without simultaneous cytokine hemoadsorption during cardiopulmonary bypass. Besides preoperative patient characteristics, postoperative lactate clearance, vasopressor administration and mean arterial pressure, perioperative complication, and 30-day mortality rates were retrospectively analyzed. Results Apart from an increased rate of reoperations within the CytoSorb group, baseline characteristics including the severity of ventricular dysfunction and consecutive signs of end-organ failure were similar in both groups. Preoperative short-term mechanical circulatory support bridging was comparable (66.7 vs. 75%; p = 0.66) prior to LVAD implantation. Procedural characteristics including intraoperative volume management and postoperative vasopressor administration were similar in both groups. There was no difference regarding postoperative lactate clearance, although postoperative mean arterial pressure was significantly higher in the control group (71.3 vs. 57.4 mm Hg; p < 0.01). Furthermore, the 30-day mortality rate was significantly higher in the CytoSorb group (33.3 vs. 0.0%; p = 0.01). Conclusion Extracorporeal cytokine hemoadsorption during high-risk LVAD implantation was not associated with a decrease of postoperative vasopressor support, improved hemodynamics, or an accelerated lactate clearance. [ABSTRACT FROM AUTHOR]

Studies the heat conduction from spheroids. Types of spheroids; Solutions for the problem of heat conduction from a sphere.

As the world responds to the global crisis of the COVID-19 pandemic an increasing number of patients are experiencing increased morbidity as a result of multi-organ involvement. Of these, a small proportion will progress to end-stage lung disease, become dialysis dependent, or both. Herein, we describe the first reported case of a successful combined lung and kidney transplantation in a patient with COVID-19. Lung transplantation, isolated or combined with other organs, is feasible and should be considered for select patients impacted by this deadly disease. [ABSTRACT FROM AUTHOR]

Abstract: We show that the two dimensional Navier–Stokes equations in the stream function and vorticity form with nonhomogeneous boundary conditions have a unique solution with a stream function having two space derivatives. [Copyright &y& Elsevier]

The donor shortage poses a major limitation to use of heart transplantation. Novel strategies such as use of expanded-criteria donors with prolonged ischemia times are being employed to address this need. Recent developments in static hypothermia have allowed for the safe use of cardiac allografts with prolonged ischemic times. We present the case of a 68-year-old woman with valvular cardiomyopathy refractory to medical therapy who underwent orthotopic heart transplantation with a cardiac allograft exposed to elevated ischemic times. This was achieved through use of the federally approved SherpaPak Cardiac Transport System for transportation of the allograft. This method of static hypothermic organ preservation allowed for a 330-minute total ischemic time, including 283 minutes of storage within the preservation system. The patient tolerated the procedure well and was discharged on postoperative day 10, with excellent graft function and no evidence of rejection 3 months postoperatively. Though traditionally ischemic times of 240 minutes or less are recommended for cardiac allografts, we demonstrate, to our knowledge, the longest reported ischemic time of 330 minutes via use of a novel method of static hypothermia for organ preservation. The recipient had an excellent outcome postoperatively, demonstrating the potential for this new organ preservation system to expand the donor pool and improve access and use of heart transplantation. [ABSTRACT FROM AUTHOR]

Intra-aortic balloon pump (IABP) therapy is often used to bridge patients to durable left ventricular assist device (LVAD). We examined the hemodynamic changes following IABP insertion in cardiogenic shock patients requiring LVAD therapy. We performed a retrospective observational study of patients receiving an IABP as a bridge to LVAD from 2015-2021. Hemodynamic metrics including right atrial pressure (RAP), pulmonary artery pressures (PAP), mixed venous oxygen saturation (SvO2), and cardiac output/indices (CO/CI) were collected at 1-hour, 24-hours, and 48-hours post-IABP insertion as well as day of insertion of the LVAD. Post-IABP hemodynamic measures were compared to the pre-IABP state. Heart failure-related labs were drawn prior to IABP and compared to 48 hours post-IABP. All p values < 0.05 were considered significant. A total of 104 patients were analyzed. Mean (SD) age was 55.8 (11.9) years old and median (IQR) days on IABP support was 4.5 (3.1). Improvement in RAP and PAP was noted at 24- and 48-hours post-IABP placement and on the day of LVAD placement. SvO2 and CO/CI were higher at all time points following IABP (Figure). All labs with the exception of sodium were improved at the 48-hour interval (Table). IABP therapy improves hemodynamic profiles in cardiogenic shock patients bridged to LVAD as early as 1-hour post-placement and persists until the day of LVAD implantation. IABPs can serve as an effective platform to bridge selected patients to durable LVAD. Future research should be focused on the identification of predictors of IABP hemodynamic response in advanced heart failure patients. [ABSTRACT FROM AUTHOR]

Short-term mechanical circulatory support (MCS) plays an increasing role in patients in acute cardiogenic shock as a bridge-to-decision strategy for potential left ventricular assist device (LVAD) implantation. Microaxial flow pump (MFP) therapy thereby is gaining increasing importance as a complement to venoarterial extracorporeal membrane oxygenation (VA-ECMO) therapy for left ventricular unloading. The aim of the study was to compare VA-ECMO vs. VA-ECMO + MFP therapy as short-term MCS prior to LVAD implantation. 183 patients with advanced heart failure underwent LVAD implantation at our center between 2010 - 2020. Of these, 34 patients had short-term MCS with VA-ECMO (n=16, group 1) or VA-ECMO + MFP (n=18, group 2) before LVAD implantation. Data were retrospectively analysed. Both groups consisted only of patients in acute cardiogenic shock (INTERMACS profile 1 + 2, age (group 1 vs. group 2: 50.1±9.8 vs. 52.7±7.3 years, p=0.1)). Short-term MCS was performed until LVAD implantation. Time on short-term MCS (6.6±3.8 vs. 8±4.9 days, p=0.4) showed no significant difference between the groups. Implanted permanent devices were HVAD and Heart Mate 3 (HM3) (group 1: HVAD: 88%, HM3: 12%; group 2: HVAD: 55%, HM3: 45%). Procedural characteristics showed no significant differences in terms of access, procedure time or volume management. Rates of in-hospital stroke (5.5 vs. 0%, p=1.0) and major bleeding (0 vs. 0%, p=1.0) were low in both groups. Rate of concomitant temporary RVAD implantation was similar in both groups (43.7 vs. 38.8%, p=1.0). Consecutive right heart failure in the first 3 months occurred in both groups (6,3 vs.5.5%, p=1.0). 30-day (12.5 vs. 17%, p=1.0) and 1-year mortality (31.3 vs. 22.2%, p=0.7) revealed no significant differences between groups. Our study shows a similar outcome after short-term MCS and LVAD implantation in both groups resulting in a 30-day survival of >80% in our high-risk cohorts. The effect of additional MFP needs to be proven in further studies. [ABSTRACT FROM AUTHOR]

Malnutrition and cardiac cachexia with low body mass index (BMI) are recognized pre-implant risk factors for adverse post-LVAD outcomes. The obesity paradox has defined a protective effect of higher BMI in terms of outcomes in heart failure (HF) patients. We evaluated the interaction of nutritional state (estimated by albumin) with BMI on LVAD outcomes. A retrospective cohort study of patients implanted with continuous flow LVAD at our center between 2006 and 2022 was performed. Patients were stratified into four quartiles based on nutritional status and BMI. We considered malnourished to be albumin <3.5g/dL and well-nourished as albumin > 3.5g/dL. We considered obesity to be a BMI > 30kg/m2 and non-obese as BMI <30kg/m2. We created 4 groups - malnourished, obese (MN-Obese); malnourished, non-obese (MN-NonObese); well-nourished, obese (N-Obese); and well-nourished, non-obese (N-NonObese). We compared time to first HF exacerbation post-LVAD implantation amongst the 4 groups. 745 patients were included for analysis: 25% (n=185) MN-Obese, 45% (340) MN-NonObese, 14% (105) N-Obese and 16% (117) N-NonObese. Independent of nutritional status, obese patients were more likely to self-report as Black (p = 0.021), and have diabetes, hypertension and OSA (p = < 0.001 for all). Obese patients had higher incidence of first HF exacerbation than non-obese patients regardless of nutritional status (Figure). At 1 year, 20% of MN-NonObese and 13% of N-NonObese patients had been hospitalized compared to 32% of MN-Obese and 37% of N-Obese patients (p < 0.001). One year survival was similar between the groups. Although there was no association with survival, obese LVAD patients have a higher rate of heart failure hospitalizations than non-obese. Malnutrition appears to increase the rate of hospitalization in non-obese LVAD patients, but not in the obese. Further investigation is warranted to understand the impact of BMI and nutritional status on long-term clinical outcomes with LVAD therapy. [ABSTRACT FROM AUTHOR]

This study investigated the efficacy of prophylactic intraoperative intra-aortic balloon pump ( IABP) usage in chronic heart failure patients with severely reduced left ventricular function undergoing elective cardiac surgery. Between January 2008 and December 2012, 107 patients with severely reduced left ventricular ejection fraction ( LVEF <35%) received prophylactic intraoperative IABP implantation during open-heart surgery. Surgical procedures performed were isolated coronary artery bypass grafting ( CABG) in 35 patients (32.7%), aortic valve replacement in 12 (11.2%), mitral valve repair or replacement in 15 (14.0%), combined valve and CABG procedures in 27 (25.2%), and other surgical procedures in 18 (16.8%). Results and outcomes were compared with those in a propensity score-matched cohort of 107 patients who underwent cardiac surgery without intraoperative IABP implantation. Matching criteria were age, gender, LVEF, and surgical procedure. Duration of intensive care unit ( ICU) stay, duration of hospital stay, and 30-day mortality were markers of outcome. In the IABP group, mean patient age was 69.1 ± 13.7 years; 66.4% (70) were male. All IABPs were placed intraoperatively. Mean duration of IABP application time was 42.4 ± 8.7 h. IABP-related complications occurred in five patients (4.7%), including one case of inguinal bleeding, one case of mesenteric ischemia, and ischemia of the lower limb in three patients. No stroke or major bleeding occurred during IABP support. Mean durations of ICU and hospital stay were 3.38 ± 2.15 days and 7.69 ± 2.02 days, respectively, in the IABP group, and 4.20 ± 3.14 days and 8.57 ± 3.26 days in the control group, showing statistically significant reductions in duration of ICU and hospital stay in the IABP group ( ICU stay, P = 0.036; hospital stay, P = 0.015). Thirty-day survival rates were 92.5 and 94.4% in the IABP and control group, respectively, showing no statistically significant difference ( P = 0.75). IABP usage in chronic heart failure patients with severely reduced LVEF undergoing cardiac surgery was safe and resulted in shorter ICU and hospital stay but did not influence 7- and 30-day survival rates. [ABSTRACT FROM AUTHOR]

Clinical data on patients after left ventricular assist device (LVAD) explantation are scarce. There are several surgical approaches for explantation of an LVAD after recovery of cardiac function. Thus, remaining ventricular assist device components bear significant risks of infection or thrombosis. We hereby report our technique and single-centre experience with explantation of LVADs using a double patch technique. From March 2019 - April 2021, 4 patients underwent LVAD explantation after myocardial recovery (HVAD, n=2; HeartMate 3, n=2). Mean patient age was 50.2 years (100% male) and mean time on LVAD was 19.8 months. Primary heart failure aetiology was dilated cardiomyopathy (n=3) and myocarditis (n=1). LVAD explantation was performed using a median sternotomy and cardiopulmonary bypass. The LVAD was stopped, and the outflow graft clamped. The outflow graft was ligated and sutured close to the aortic anastomosis. The driveline was clipped and removed. Under induced fibrillation the attachment of the LVAD was released from the apical cuff and the LVAD removed. A round pericardial patch was fixed from inner of the ventricle with twelve 3-0 Prolene sutures stitched from the ventricle towards the suture ring of the LVAD. This already seals the apex of the heart. An additional Goretex patch is continuously sutured epicardially over the suture ring. The ventricle is carefully deflated. The patient is then weaned from ECC. The four cases showed technically uncomplicated explantation of the LVADs. During the follow-up, a 30-day survival and 1 year survival of 100% was observed. There were no bleeding complications or thromboembolic events during follow-up. This technique allowed discontinuation of anticoagulation in all patients. LVAD explantation with the double patch technique is feasible and safe. This technique allows discontinuation of anticoagulation. We have had no bleeding or thromboembolic events at our center. Overall, there was a 30-day survival of 100%. Further studies are needed to provide better evidence for LVAD explantation and long-term follow-up. [ABSTRACT FROM AUTHOR]

Refractory right ventricular failure has significant morbidity and mortality. Extracorporeal membrane oxygenation is indicated when medical interventions are deemed ineffective. However, it is still being determined if one configuration is better. We conducted a retrospective analysis of our institutional experience comparing the peripheral veno-pulmonary artery (V-PA) configuration versus the dual-lumen cannula with the tip in the pulmonary artery (C-PA). The analysis of a cohort of 24 patients (12 patients in each group). There was no difference in survival after hospital discharge (58.3% in the C-PA group compared to 41.7% in the V-PA group, p = 0.4). Among the C-PA group, there was a statistically significant shorter ICU length of stay (23.5 days [interquartile range {IQR} = 19-38.5] vs. 43 days [IQR = 30-50], p = 0.043) and duration of mechanical ventilation (7.5 days [IQR = 4.5-9.5] compared to (16.5 days [IQR = 9.5-22.5], p = 0.006) in the V-PA group. In the C-PA group, there were lower incidents of bleeding (33.33% vs. 83.33%, p =0.036) and combined ischemic events (0 vs. 41.67%, p = 0.037). In our single-center experience, the C-PA configuration might have a better outcome than the V-PA one. Further studies are needed to confirm our findings., Competing Interests: Disclosure: The authors have no conflicts of interest to report., (Copyright © ASAIO 2023.)

Severe primary graft dysfunction (PGD) is the leading cause of early postoperative mortality following orthotopic heart transplantation (OHT). Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has been used as salvage therapy. This study aimed to evaluate the outcomes in adult OHT recipients who underwent VA-ECMO for severe PGD. We retrospectively reviewed 899 adult (≥18 years) patients who underwent primary OHT at our institution between 1997 and 2017. Recipients treated with VA-ECMO (19, 2.1%) exhibited a higher incidence of previous cardiac surgery ( p = .0220), chronic obstructive pulmonary disease ( p = .0352), and treatment with a calcium channel blocker ( p = .0018) and amiodarone ( p = .0148). Cardiopulmonary bypass ( p = .0410) and aortic cross-clamp times ( p = .0477) were longer in the VA-ECMO cohort and they were more likely to have received postoperative transfusion ( p = .0013); intra-aortic balloon pump (IABP, p < .0001), and reoperation for bleeding or tamponade ( p < .0001). The 30-day, 1-year, and overall survival after transplantation of non-ECMO patients were 95.9, 88.8, and 67.4%, respectively, compared to 73.7, 57.9, and 47.4%, respectively in the ECMO cohort. Fourteen (73.7%) of the ECMO patients were weaned after a median of 7 days following OHT (range: 1-12 days). Following OHT, VA-ECMO may be a useful salvage therapy for severe PGD and can potentially support the usage of marginal donor hearts., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Shudo, Alassar, Wang, Lingala, He, Zhu, Hiesinger, MacArthur, Boyd, Lee, Currie and Woo.)

Combined heart-liver transplant is an emerging option for patients with indications for heart transplantation and otherwise prohibitive hepatic dysfunction. Heart-liver transplantation is particularly relevant for patients with single ventricle physiology who often develop Fontan-associated liver disease and fibrosis. Although only performed at a limited number of centers, several approaches to combined heart-liver transplantation have been described. The en bloc technique offers several potential advantages over the traditional sequential technique. Specifically, en bloc heart-liver transplantation may allow improved hemodynamics, decreased bleeding, reduced liver allograft ischemic time, and may result in reduced rates of graft dysfunction. Here we describe our center's en bloc heart-liver procurement technique in detail, with the aim of allowing broader use and standardization of this technique., Competing Interests: The authors declare no funding or conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: The impact of transcatheter aortic valve implantation (TAVI) on left ventricular (LV) mass regression is not well defined. We aimed to measure LV mass regression, changes in LV volumes and dimensions, as well as mitral valve function after TAVI., Methods: Eighty patients who underwent TAVI between 2008 and 2010 were studied. Echocardiographic findings before procedure and at 6- and 12-month follow-up were analyzed., Results: Aortic valve area increased from 0.71 (0.27) cm before procedure to 1.89 (0.64) cm at 12 months (P < 0.001), which was associated with reduction in peak [80.79 (23) vs 16.9 (6.5) mm Hg, P < 0.001] and mean [47.65 (14.2) vs 8.77 (3.29) mm Hg, P < 0.001] gradients. At 1 year, there was a change in LV end-systolic volume [46.12 (36.6) to 48.96 (4.05) mL, P = 0.042] and LV mass [202.4 (92.2) to 183.6 (98.2) g, P = 0.04]. Left ventricular mass index regressed from 130.7 (28.9) to 122.1 (28.9) g/m (P = 0.01). Maximum wall thickness decreased from 1.28 (0.18) to 1.25 (0.17) cm (P < 0.001). There was no significant change in LV ejection fraction, LV end-systolic and end-diastolic diameters, as well as mitral valve regurgitation., Conclusions: Transcatheter aortic valve implantation is associated with significant regression of LV hypertrophy at 1 year. However, this regression was not associated with changes in LV systolic and diastolic functions, size, or changes in mitral valve regurgitation.

Objective: Transcatheter aortic valve implantation (TAVI) is considered the standard of care for patients with severe symptomatic aortic stenosis unsuitable for surgery. However, short- and long-term mortality after TAVI are still relatively high. The aim of this study was to establish survival, predictive factors, and causes of mortality after TAVI at early and midterm follow-up., Methods: Between December 2007 and May 2012, a total of 119 patients with symptomatic severe aortic stenosis underwent 121 TAVI procedures. The mean ± SD age was 81 ± 9 years, and 59% were men. The mean ± SD logistic European System for Cardiac Operative Risk Evaluation was 22 ± 15. Seventy-five patients (63%) were in New York Heart Association functional class III to IV. The transfemoral approach was used in 76% of the patients. One hundred ten patients (91%) had the CoreValve prosthesis, and 11 (9%) had an Edwards SAPIEN valve. Baseline characteristics, procedural complications, and outcomes were collected prospectively. Clinical outcomes were defined according to the Valve Academic Research Consortium criteria. Follow-up was completed for 100% of the patients at a median of 1.3 years (range, 0-4.5)., Results: The total number of deaths was 36 (30%). One-month mortality was 4.2%. Actuarial survival was 83.2%, 76.5%, and 68.2% at 1, 2, and 3 years, respectively. Acute kidney injury occurred in 12.3% of the patients, none of whom required dialysis during hospitalization. Twenty-one patients (17.6%) had new conduction abnormalities that required permanent pacemaker implantation before hospital discharge. The incidence of major vascular injury and stroke was 2.4% and 4.1%, respectively. Survival was significantly adversely affected by preprocedural left ventricular dysfunction (P = 0.04), history of atrial fibrillation (P = 0.03), prior heart block (P < 0.01), and critical preoperative state (P < 0.01). Twelve (33%) of the 36 deaths were due to bronchopneumonia. In 12 (33%) of the 36 patients who died, mortality was related to cardiac causes. When a death occurred within the first 30 days, it was mainly cardiac in nature (80%). Twelve patients (34%) died because of a variety of other reasons such as pulmonary embolism, stroke, cancer, renal failure, and sepsis., Conclusions: Preprocedural left ventricular dysfunction, atrial fibrillation, and heart block are independent predictive factors of all-cause mortality. Early mortality was mainly cardiac in origin. Most of the late deaths were caused by noncardiac reasons, with bronchopneumonia being reported as the most common cause of late mortality.

Objective: Acute kidney injury (AKI) is a common complication after surgical aortic valve replacement and is associated with increased mortality. Transcatheter aortic valve implantation (TAVI) is now considered the criterion standard treatment of patients with severe symptomatic aortic stenosis ineligible for surgery. The aim of this study was to establish the incidence, risk factors, and prognostic consequences of AKI after TAVI and at 1-year follow-up in a single center., Methods: Between December 2007 and March 2011, a total of 79 patients with severe aortic stenosis who underwent 81 TAVI procedures with the Medtronic CoreValve System or the Edwards SAPIEN heart valve were included. Baseline characteristics and procedural complications were recorded. Acute kidney injury was defined according to the Valve Academic Research Consortium criteria (modified risk, injury, failure, loss, and end-stage kidney disease criteria)., Results: The mean age was 84 (78-87) years; 49 were men. After TAVI, 10 patients (12.3%) developed AKI, which had completely resolved in 9 patients before hospital discharge. Nine patients (10%) had mild AKI (stage 1) and only one patient (10%) experienced moderate AKI (stage 2) according to Valve Academic Research Consortium definitions. The predictive factors of AKI were diabetes (odds ratio, 6.722; P = 0.004) and preoperative creatinine level greater than 104 μmol/L (odds ratio, 1.024; P = 0.02). Thirteen patients (16.4%) died within 1 year after TAVI. Three of the nonsurvivors (3.7%) developed AKI postoperatively. Acute kidney injury was, however, not a predictive factor of 1-year mortality after TAVI., Conclusions: Acute kidney injury occurred in 12.3% of the patients after TAVI and persisted in only one patient before hospital discharge. Diabetes and preoperative creatinine level were found to be the main predictive factors of AKI after TAVI. Acute kidney injury was not associated with increased 1-year mortality.