Continuous-Flow Ventricular Assist Device Research Articles

(1364) - Pulsatile versus Continuous Flow Ventricular Assist Device as a Bridge to Transplantation for the Pediatric Failing Fontan

(1364) - Pulsatile versus Continuous Flow Ventricular Assist Device as a Bridge to Transplantation for the Pediatric Failing Fontan

On the prediction of the effect of bi-ventricular assistance after cardiac explantation on the vascular flow physiology: A numerical study

Heart failure is a chronic and progressive condition characterized by the heart’s inability to pump sufficient blood to meet the body’s metabolic demands. It is a significant public health concern worldwide, associated with high morbidity, mortality, and healthcare costs. For advanced heart failure cases not responding to medical therapy, heart transplantation or mechanical circulatory support with ventricular assist devices (VADs) can be considered. In the specific case of bi-ventricular heart failure a replacement of both ventricles is required. In this context a Total Artificial Heart (TAH) may be proposed as a bridge to transplant solution. Additionally, bi-ventricular assist devices (BiVADs) are available to support both ventricles simultaneously. However Bi-ventricular heart failure management is difficult with poor outcomes. New surgical procedures appear to propose solutions after both ventricle failure. One of these intervention uses two continuous-flow VADs as a total artificial heart after cardiac explantation due to myocardial sarcoma. Unfortunately, this procedure makes patient management very difficult as pulmonary pressures and flow rate are no longer measurable after the surgical procedure. The setting of both pumps is hence a complex task for patient management. This article aims at helping clinicians on patient management undergoing double assistance after cardiac explantation by predicting the different outcomes on the vascular grid for all the possible rotational speed combination using a lumped model. Results provide a range of both pump operating conditions suitable for delivering a physiologically adapted flow to the vascular grid when combined with hypotensive treatments.

PEDS5: VAD Discharge at Pediatric Centers- Why can’t we get home?

Background: The use of intra-corporeal continuous flow ventricular assist devices (CF-VAD) has allowed patients with advanced heart failure to be discharged home. Moreover, it has been shown that heart transplant (HTx)>30 days after VAD implant offers some survival benefit. Despite this, only about 50% of patients at pediatric centers are discharged, while others remain in hospital until HTx. We sought to characterize the cohort of patients who are transplanted during their index VAD admission as a means to identify potential barriers to discharge. Methods: Using the Advanced Cardiac Therapies Improving Outcomes Network (ACTION) registry, individuals who underwent implant with a dischargeable VAD (HVAD and HM3) at a pediatric center were included. Data including patient demographics, characteristics and clinical course were compared between the discharged versus hospitalized cohorts. Patients who recovered or died during their VAD admission were excluded. Results: From December 2012 to June 2022, 220 patients underwent implant with HM3 (n=108) or HVAD (n=111) across 32 pediatric centers. Overall, 28% (62/220) of patients remained hospitalized until HTx. There was no significant difference in age, underlying diagnosis, days to extubation, INTERMACS profile, or history of ECMO in those who were discharged versus hospitalized. There was also no significant difference in adverse events including stroke, bleeding, infection, hepatic or renal dysfunction, or right heart failure between the two groups (See Table 1). Patients with HM3 were less likely to be discharged if lower BSA (p=0.05) or on BiVAD support (p=0.04). Conclusion: Although discharge in VAD patients at pediatric centers is improving, nearly one-third of patients undergoing implant with dischargeable VADs remain hospitalized until transplant. There was no significant difference in markers of severity of illness or adverse events in those who remain hospitalized versus discharged. Thus, perceived non-medical barriers by providers or families may be limiting discharge at pediatric centers and may be a potential target for further education.

P102: Hemodynamic Ramp Studies in Continuous Flow Ventricular Assist Device in Fontan Patients: A Case Series

Purpose: There is limited experience in patients with single ventricle physiology using the Heartmate III (HM3). With a growing population of failing Fontan patients and long wait times for cardiac transplantation, the need for an appropriate strategy for durable mechanical support is increasing. Determination of the best strategies to optimize the HM3 device in Fontan circulation has not yet been elucidated. Methods: A retrospective case series of three patients with failing Fontan on VAD who underwent ramp studies by cardiac catheterization were reviewed with the intent of optimizing hemodynamics. Results: All patients had hypoplastic left heart syndrome, completed Fontan, and were on durable VAD. Patient 1 was a 19y male on a Heartware at 2640 rpm. Initial hemodynamics with a PCWP of 25 mmHg and Fontan pressure of 25 mmHg. Increase in RPM to 2900 bpm showed no change in Fontan pressure and decrease in PCWP to 20 mmHg. No change on adjustment back to 2700 RPM though improvement noted in tricuspid regurgitation in echocardiogram. Patient 2 was a 13y male on HM 3 at 5000 rpm with PCWP 15 mmHg and Fontan 19 mmHg. Tricuspid regurgitation on echocardiogram improved from moderate to mild and final VAD speed was 5200 RPM. Patient 3 was a 12y male on HM3 at 5100 rpm with PCWP of 15 mmHg and Fontan 18 mmHg. Increase up to 5500 RPM with no change in PCWP and Fontan at 17mmHg. Final speed at 5200 RPM with PCWP of 14mmHg and Fontan 17 mmHg. Conclusions: Significant hemodynamic changes on catheterization ramp study were not found. Increase in support from the VAD was made due to clinical indications and echocardiographic assessment of atrioventricular valve regurgitation. Hemodynamic data was useful in reassuring that changes made to the device were not detrimental to the patient. Further data on ramp studies and indications for changes in device speed will be useful in the care of these patients.

P15: Durable Continuous-Flow Ventricular Assist Device For Biventricular Circulatory Support

Objective: The biventricular assist device (BVAD, Fig. 1A) implantation is indicated for severe biventricular heart failure (BHF). We are developing an innovative, automatic, universal ventricular assist device (UVAD, Fig. 1B, 1C, and 1D), intended for biventricular or for single ventricular support (RVAD or LVAD). Pump rotor can move axially to regulate the impeller discharge aperture size, depending on the pressure difference between the inflow and outflow and pump speed. Herein, we report on UVAD research progress. Methods: The hardware used during RVAD/LVAD studies, consisted of a microcontroller development board (NXP FRDM-KV31F) in conjunction with a 3-phase BLDC motor driver board (NXP FRDM-MC-LVPMSM). Two UVAD pumps incorporated into the biventricular circulatory mock loop were used (Abbott Laboratories PVAD™, Abbott Park, IL, USA) to simulate BHF. Each interchangeable cannula has been designed as a four-piece assembly with a threaded connection and face seal with the inflow port of the UVAD (Fig. 1E). Computational flow dynamics (CFD) model (Fig. 1F) enabled automatic re-meshing of the internal fluid volume with vertical repositioning of the rotor and resulting changes in aperture size (ANSYS [Canonsburg, PA, USA] software, including DesignModeler, ANSYS-Meshing, CFX, and CFD-Post). Results: The hemodynamic requirements were met with both RVAD and LVAD settings. Flow pattern, shear stress, and residence times were similar at RVAD and LVAD nominal conditions. Interchangeable inflow cannulas allowed customization of cannulation strategies in RVAD and LVAD conditions, showing stable hemodynamic support with single or dual-device configurations. Conclusion: The UVAD architecture for single or dual-device configurations has been demonstrated in simulated BHF conditions. Device features such as incorporated pressure regulator and interchangeable inflow cannula enable patient centered customization of device use.Figure 1. A - BVAD setup; B - UVAD; C - Device aperture design; D - Cross section; E – Interchangeable inflow cannulas; F – Impeller regions and CFD contour plot.

P16: Dual Continuous-Flow Ventricular Assist Devices Operation With a Single Controller: Early Assessment for Biventricular Support

Objective: The biventricular assist device (BVAD) is a treatment option for severe biventricular heart failure (BHF). For left and/or right ventricular assist device (LVAD and/or RVAD), a standalone controller unit is required for operation and control. In this work we sought to evaluate the feasibility of dual-device setup using continuous-flow (CF) universal ventricular assist device (UVAD, Fig. 1A) operation using a single controller unit. Methods: Two pneumatic pumps (Abiomed AB5000™, Danvers, MA, USA incorporated into the biventricular circulatory mock loop were used for simulation) driven by a dual-output driver (Thoratec Model 2600, Pleasanton, CA, USA) were used to simulate the left and right heart failure conditions. Systolic BHF conditions were simulated and two UVAD configurations (LVAD - primary controller mode, RVAD - secondary controller mode, set at 80% of LVAD work) were tested at various speeds for performance. Custom user interface software was developed to enable intuitive control and monitoring of the device (Fig. 1B). Results: The hemodynamic requirements were met in both RVAD and LVAD arrangement (Fig. 1C,D). The LVAD flow values provided guidance for RVAD control. In all simulated BHF conditions, both LVAD and RVAD (UVADs) provided optimal performance and demonstrated stable hemodynamics. Conclusion: The feasibility of a single controller system architecture for dual CF device operation has been shown. Both UVAD’s demonstrated optimal performance and communication for dual-device support configurations in BHF. Future direction should consist of technology characterization and optimizations.Figure 1. A - UVAD design; B - BVAD controller interface. Red window, LVAD (primary); Blue window, RVAD (secondary); C- LVAD performance; D –RVAD performance.

Von Willebrand Factor and Angiopoietin-2 are Sensitive Biomarkers of Pulsatility in Continuous-Flow Ventricular Assist Device Patients.

Nonsurgical bleeding occurs in a significant proportion of patients implanted with continuous-flow ventricular assist devices (CF-VADs) and is associated with nonphysiologic flow with diminished pulsatility. An in vitro vascular pulse perfusion model seeded with adult human aortic endothelial cells (HAECs) was used to identify biomarkers sensitive to changes in pulsatility. Diminished pulsatility resulted in an ~45% decrease in von Willebrand factor (vWF) levels from 9.80 to 5.32 ng/ml (n = 5, p < 0.05) and a threefold increase in angiopoietin-2 (ANGPT-2) levels from 775.29 to 2471.93 pg/ml (n = 5, p < 0.05) in cultured HAECs. These changes are in agreement with evaluation of patient blood samples obtained pre-CF-VAD implant and 30-day postimplant: a decrease in plasma vWF level by 50% from ~45.59 to ~22.49 μg/ml (n = 15, p < 0.01) and a 64% increase in plasma ANGPT-2 level from 7,073 to 11,615 pg/ml (n = 8, p < 0.05). This study identified vWF and ANGPT-2 as highly sensitive to changes in pulsatility, in addition to interleukin-6 (IL-6), IL-8, and tumor necrosis-α (TNF-α). These biomarkers may help determine the optimal level of pulsatility and help identify patients at high risk of nonsurgical bleeding.

Toward a Self-Actuating Continuous Flow Ventricular Assist Device: The Pudding Is in the Proof.

Toward a Self-Actuating Continuous Flow Ventricular Assist Device: The Pudding Is in the Proof.

Ten-year retrospective cohort analysis of ventricular assist device infections.

The number of patients treated by ventricular assist devices (VAD) and the duration of VAD treatment is increasing. One of the main complications in terms of morbidity and mortality for VAD patients are microbial infections. With this study, we aimed to investigate the epidemiology and microbiological characteristics of infections occurring in a VAD population to identify modifiable factors. We retrospectively analyzed patient characteristics, treatments and outcomes of VAD-specific/related infections. All patients implanted in our institution with a continuous flow VAD between January 2009 and January 2019 were included. Risk factors for VAD infection were assessed using simple and multiple linear regressions. Of the 104 patients screened, 99 were included in the analysis, the majority of which were men (78%). At implantation, the mean age was 56 years and the median time on VAD support was 541 days. The overall infection rate per year per patient was 1.4. Forty-seven patients (60%) suffered from VAD-specific/related infection. Half of all infection episodes occurred in the first 4 months but the proportion of VAD-specific/related infection was higher after the first 4 months (74% of all infection). Using regression models, no patient specific risk factors were associated with VAD-specific/related infections. No predictive factors for infection during VAD support were identified in this study. By extension, diabetes, renal insufficiency, age or high BMI are not sufficient to deny a patient access to ventricular support.

Loss of pulsatility with continuous-flow left ventricular assist devices and the significance of the arterial endothelium in von-Willebrand factor production and degradation.

Patients on continuous flow ventricular assist devices (CF-VADs) are at high risk for the development of Acquired von-Willebrand Syndrome (AVWS) and non-surgical bleeding. von Willebrand Factor (vWF) plays an essential role in maintaining hemostasis via platelet binding to the damaged endothelium to facilitate coagulation. In CF-VAD patients, degradation of vWF into low MW multimers that are inefficient in facilitating coagulation occurs and has been primarily attributed to the supraphysiological shear stress associated with the CF-VAD impeller. In this review, we evaluate information from the literature regarding the unraveling behavior of surface-immobilized vWF under pulsatile and continuous flow pertaining to: (A) the process of arterial endothelial vWF production and release into circulation, (B) the critical shear stress required to unravel surface bound versus soluble vWF which leads to degradation, and (C) the role of pulsatility in on the production and degradation of vWF. Taken together, these data suggests that the loss of pulsatility and its impact on arterial endothelial cells plays an important role in the production, release, unraveling, and proteolytic degradation of vWF into low MW multimers, contributing to the development of AVWS. Restoration of pulsatility can potentially mitigate this issue by preventing AVWS and minimizing the risk of non-surgical bleeding.

Abstract 10824: Pulsatile Ventricular Assist Device Prior to Pediatric Heart Transplantation is Associated With Favorable Post-Transplant Hemodynamics

Background: Ventricular assist device (VAD) support is increasingly used in end-stage pediatric heart failure management. The effects of pulsatile VAD (PVAD) and continuous-flow VAD (CVAD) support on hemodynamics (HDS) after pediatric heart transplant (HT) are unknown. We compared the difference in post-HT HDS between patients supported with PVAD vs CVAD. Methods: We collected measures of pulmonary vascular resistance index (PVRi), cardiac index (CI), and pulmonary wedge pressure (PCWP) in the 1 st year post-HT among patients that underwent HT at our institution between 2013-2020. We defined normal HDS as a PVRi &lt; 3Wu/m 2 , CI &gt; 2.5L/min/m 2 , and PCWP &lt; 12mmHg. Linear regression analysis and Cox regression were performed to compare differences in HDS post-HT. Results: Demographics/clinical features of the patients supported with PVAD (n=18) and CVAD (n=41)are described in Table 1. PVR, CI, and PCWP are plotted in Figure 1. Accounting for confounders, the mean PCWP over the 1 st year is lower in the PVAD group (-0.83 [-1.72-0.07], p=0.07) while the mean CI and mean PVR are similar. In the PVAD cohort, 16 (89%) had normalized HDS in the 1st year vs 17 (42%) in the CVAD group (Log Rank: p&lt;0.001). In multivariate analysis, PVAD was the only variable associated with normalization of HDS (HR 3.87 [1.03-14.52], p=0.045). Compared to our non-VAD cohort (n=97), patients with PVAD were as likely to have HDS normalization by 1 year, but CVAD patients trended towards being less likely to normalize (HR 0.58, p=0.08). Conclusion: Patients supported with PVAD pre-HT have lower PCWP and were more likely to achieve normalization of HDS post-HT compared to patients supported with CVAD.

The Anemia Stress Index-Anemia, Transfusions, and Mortality in Patients with Continuous Flow Ventricular Assist Devices.

We aimed to identify a simple metric accounting for peri-procedural hemoglobin changes, independent of blood product transfusion strategies, and assess its correlation with outcomes in patients undergoing left ventricular assist device (LVAD) implantation We included consecutive patients undergoing LVAD implantation at a single center between 10/1/2008 and 6/1/2014. The anemia stress index (ASI), defined as the sum of number of packed red blood cells transfused and the hemoglobin changes after LVAD implantation, was calculated for each patient at 24 h, discharge, and 3 months after LVAD implantation. Our cohort included 166 patients (80.1% males, mean age 56.3 ± 15.6 years) followed up for a median of 12.3 months. Increases in ASI per unit were associated with a higher hazard for all-cause mortality and early RV failure. The associations between the ASI and all-cause mortality persisted after multivariable adjustment, irrespective of when it was calculated (adjusted HR of 1.11, 95% CI 1.03–1.20 per unit increase in ASI). Similarly, ASI at 24 h after implant was associated with early RV failure despite multivariable adjustment (OR 1.09, 95% CI 1.05–1.14). We present a novel metric, the ASI, that is correlated with an increased risk for all-cause mortality and early RV failure in LVAD recipients.

Chest Compressions in Pediatric Patients With Continuous-Flow Ventricular Assist Devices: Case Series and Proposed Algorithm.

Patients with continuous flow ventricular assist devices (CF-VAD's) in the systemic ventricle (left ventricle or single ventricle) often have no palpable pulses, unreliable pulse oximetry waveforms and non-pulsatile arterial waveforms despite hemodynamic stability. When circulatory decompensation occurs, standard indicators to begin cardiopulmonary resuscitation (CPR) which are used in other pediatric patients (i.e., significant bradycardia or loss of pulse) cannot be applied in the same fashion. In this population, there may already be pulselessness and development of bradycardia in and of itself would not trigger chest compressions. There are no universal guidelines to dictate when to consider chest compressions in this population. As such, there may be a delay in decision-making or in recognizing the need for chest compressions, even in patients hospitalized in intensive care units (ICU) and cared for by experienced staff who perform CPR regularly. We present four examples of pediatric cardiac ICU patients from a single center who underwent CPR between 2018 and 2019. Based on this case series, we propose a decision-making algorithm for chest compressions in pediatric patients with CF-VADs in the systemic ventricle.

Neonatal ventricular assist device implantation for high-risk hypoplastic left heart syndrome: How we do it.

Central MessageThis report highlights the technical details and operative footage of continuous-flow ventricular assist device placement in an HLHS neonate less than 24 hours old. This report highlights the technical details and operative footage of continuous-flow ventricular assist device placement in an HLHS neonate less than 24 hours old. Some neonates with single ventricle heart disease are poor candidates for surgical palliation, such as those with ventricular dysfunction, severe atrioventricular valve regurgitation, or unfavorable coronary anatomy. Recently, pulsatile-flow ventricular assist device (VAD) placement has emerged as a strategy to bridge these patients to transplantation.1Philip J. Powers E. Machado D. Colon D.L. Gupta D. Shih R. et al.Pulsatile ventricular assist device as a bridge to transplant for the early high-risk single-ventricle physiology.J Thorac Cardiovasc Surg. 2021; 162: 405-413.e4Abstract Full Text Full Text PDF PubMed Scopus (14) Google Scholar However, few centers offer mechanical circulatory support for infants, and there is a paucity of technical reports and operative videos on the topic.2Bleiweis M.S. Fudge J.C. Peek G.J. Vyas H.V. Cruz Beltran S. Pitkin A.D. et al.Ventricular assist device support in neonates and infants with a failing functionally univentricular circulation.J Thorac Cardiovasc Surg Tech. 2022; 13: 194-204Scopus (4) Google Scholar,3Maeda K. Yarlagadda V.V. Rosenthal D.N. Almond C.S. Successful use of a ventricular assist device in a neonate with hypoplastic left heart syndrome with right ventricular dysfunction.J Thorac Cardiovasc Surg. 2018; 156: e171-e173Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar Furthermore, there is concern regarding insufficient atrial decompression and persistent venous congestion with pulsatile VAD in this population.4Mackling T. Shah T. Dimas V. Guleserian K. Sharma M. Forbess J. et al.Management of single-ventricle patients with Berlin Heart EXCOR ventricular assist device: single-center experience.Artif Organs. 2012; 36: 555-559Crossref PubMed Scopus (56) Google Scholar We present a video case report of a newborn with hypoplastic left heart syndrome (HLHS) and right ventricular (RV) dysfunction who received a continuous-flow VAD and hybrid stage I palliation as a successful bridge to transplantation. The patient was a term newborn male diagnosed prenatally with HLHS (mitral stenosis/aortic stenosis). Permission was granted by the patient's guardians to publish this report, and the institutional review board waived consent for this retrospective study (Pro00101549, May 2020). Transthoracic echocardiogram at birth demonstrated findings consistent with HLHS and an RV with severely depressed function and coarse trabeculations consistent with noncompaction cardiomyopathy (Figure 1, A). The tricuspid valve was apically displaced, with a tethered septal leaflet (Ebstein-like) and moderate-to-severe regurgitation (Figure 1, B). On day of life (DOL) 0, the patient was intubated for worsening lactic acidosis and pulmonary edema suggestive of cardiogenic shock. Given his clinical decompensation with severe ventricular dysfunction and tricuspid regurgitation, performing isolated pulmonary artery (PA) banding or a hybrid Norwood operation would have been insufficient to bridge the patient to transplant in our experience. Therefore, we proceeded with continuous-flow VAD implantation and hybrid stage I palliation with bilateral (PA) banding and atrial septectomy on DOL1. The surgical technique is detailed in Video 1. After median sternotomy and pericardiotomy, the great vessels were dissected circumferentially. Pursestring sutures were placed in the distal ascending aorta and right atrium. A 24-F right angle venous cannula was tunneled under the right costal margin using curved Kelly forceps and a latex cap to minimize trauma (Figure 2, A). This larger cannula was chosen to accommodate the high total flows, up to 7 to 9 L/min/m2, expected after neonatal PA banding (pulmonary flow + systemic flow with estimated pulmonary flow:systemic flow ratio of 1.5:1-2:1 and body surface area 0.23 m2). A 5/6 Berlin Heart arterial cannula was tunneled under the left costal margin. After heparinization, the ascending aorta was cannulated with an 8-F arterial cannula and the right atrial appendage was cannulated. The patient was cooled to 32 °C on bypass. In the case of a small ascending aorta measuring less than 4 mm, direct innominate artery cannulation is performed instead.5Andersen N.D. Prabhu N.K. Turek J.W. Sustained total all-region (STAR) perfusion for Norwood reconstruction.Op Tech Thorac Cardiovasc Surg. 2020; 25: 126-139Abstract Full Text Full Text PDF Scopus (3) Google Scholar Under brief circulatory arrest, a Yasargil clip was placed distal to the aortic cannula and the heart was arrested with del Nido cardioplegia via the aortic cannula side port. After myocardial arrest, the clip was moved proximal to the cannula as a crossclamp. Bypass flow was resumed. Next, an atrial septectomy was performed under pump sucker bypass. Bypass flow was reduced and an atriotomy was performed. Drop-style pump suckers were introduced into the vena cavae through the atrial incision and the septum was fully resected. The atrium was closed in 2 layers with running 6-0 polypropylene and regular bypass flow was resumed. Attention was turned to VAD outflow cannulation. A 4-mm circular punch was used to create an arteriotomy in the main PA. Two doubled-armed 5-0 polypropylene sutures were placed circumferentially around the arteriotomy as previously illustrated6Jaquiss R.D.B. Imamura M. Berlin heart implantation for congenital heart defects.Op Tech Thorac Cardiovasc Surg. 2010; 15: 162-171Abstract Full Text Full Text PDF Scopus (1) Google Scholar and brought up through the sewing ring of the Berlin cannula at the 6- and 12-o'clock positions. The cannula was secured into the PA. The aortic crossclamp was removed and rewarming initiated. The PA bands were placed by tying a CV-0 Gore-Tex tie over a 3-mm dilator on each branch PA. The patient was weaned from bypass. The VAD cannulas were connected to an Abbott PediMag blood pump after deairing and a supratherapeutic cardiac index of 7.0 to 9.0 L/min/m2 was gradually achieved on VAD support. The aortic cannula was removed, protamine administered, and a 19-F Blake drain was left in the mediastinum. A silastic membrane was placed on the open chest. The chest was closed on POD1 and bivalirudin was started. Two ductal stents (EV3 Protege self-expanding, 8 mm × 2 cm) were placed on POD2 by accessing the VAD arterial cannula with a 7-Fr sheath using the Seldinger technique after sterile preparation (Figure 2). The patient was weaned off inotropes on POD4 and remained hemodynamically stable on VAD flows of 7.0 to 9.0 L/min/m2, or 1.5 to 2.0 L/min (2400 rpm). Transthoracic echocardiogram on POD4 demonstrated well-seated VAD cannulas and ductal stent, opening of the native aortic valve with every beat, severely diminished RV function, severe tricuspid regurgitation, and continuous antegrade flow across both branch PAs. Extubation was performed on POD19. There were no thromboembolic complications on VAD support, and the patient received a heart transplant 4 months later on POD127. In this case report, we demonstrate continuous-flow VAD placement and hybrid stage I palliation as a bridge to transplantation in a neonate with HLHS. We believe there are 3 notable aspects to this report. First, to our knowledge, operative footage of a neonatal VAD implantation has not been published, and our video may serve as a useful reference. Second, our patient underwent VAD implantation at less than 24 hours of age, which is younger than patients reported in previous series. Lastly, rather than using a Dacron graft extension, we directly place the Berlin cannula into the main PA, which may eliminate a potential bleeding source. https://www.jtcvstechniques.org/cms/asset/cb032937-91ef-4499-a70e-43ece0c302f0/mmc1.mp4Loading ... Download .mp4 (130.09 MB) Help with .mp4 files Video 1Preoperative imaging, operative footage, and discussion of VAD implantation in a neonate. Video available at: https://www.jtcvs.org/article/S2666-2507(22)00360-1/fulltext. Download .jpg (.31 MB) Help with files Video 1Preoperative imaging, operative footage, and discussion of VAD implantation in a neonate. Video available at: https://www.jtcvs.org/article/S2666-2507(22)00360-1/fulltext.

Bivalirudin or Unfractionated Heparin for Anticoagulation in Pediatric Patients on Continuous Flow Ventricular Assist Device Support: Single-Center Retrospective Cohort Study

Bivalirudin is a direct thrombin inhibitor that is being increasingly used for anticoagulation in children after ventricular assist device (VAD) implantation. While the data on bivalirudin use in pulsatile flow VADs are growing, reports on its use in patients on continuous flow (CF) VAD as well as comparisons of associated outcomes with unfractionated heparin (UFH) remain limited. Retrospective cohort study. Single tertiary-quaternary referral center. All patients less than 21 years old on CF-VAD support who received bivalirudin or UFH for anticoagulation between the years 2016 and 2020. Not applicable. Clinical characteristics compared between the cohorts included time to target range of anticoagulation, markers of hemolysis, and prevalence of hemocompatibility-related adverse events such as major hemorrhagic complications, ischemic stroke, and pump thrombosis. In 42 unique patients (41 HeartWare HVAD [Medtronic, Minneapolis, MN], one HeartMate 3 LVAD [Abbott Laboratories, Abbott Park, IL]) during the study period, a total of 67 encounters of IV anticoagulation infusions (29 UFH and 38 bivalirudin) were retrospectively reviewed. In comparison with use of UFH, bivalirudin was associated with lesser odds of major bleeding complications (odds ratio [OR], 0.29; 95% CI, 0.09-0.97; p = 0.038). We failed to identify any difference in odds of major thrombotic complications (OR, 2.53; 95% CI, 0.47-13.59; p = 0.450). Eight of the patients (28%) on UFH were switched to bivalirudin due to hemorrhagic or thrombotic complications or inability to achieve therapeutic anticoagulation, while two of the patients (5%) on bivalirudin were switched to UFH due to hemorrhagic complications. Bivalirudin was used for a "washout" in eight cases with concern for pump thrombosis-six had resolution of the pump thrombosis, while two needed pump exchange. Use of bivalirudin for anticoagulation in patients on CF-VAD support was associated with lesser odds of hemorrhagic complications compared with use of UFH. Bivalirudin "washout" was successful in medical management of six of eight cases of possible pump thrombosis.

How to Heal a Broken Heart with Time and a Hybrid Mechanical Circulatory Support Armada

<h3>Introduction</h3> Continuous flow VADs are used as left ventricular assist devices (LVAD) with an off-label option as right ventricular assist device (RVAD). The Berlin Heart® EXCOR is a paracorporeal, pulsatile ventricular assist device (VAD) used for right-, left- or biventricular support. While inotropes are is the first-line treatment in patients in acute cardiogenic shock, mechanical circulatory support (MCS) in that setting has evolved and different devices are available. <h3>Case Report</h3> A 59-year-old male patient was admitted in 06/2020 for inferior pericardiectomy due to hemodynamic instability after right ventricular (RV) lead dislocation with pericardial effusion. He presented severely impaired biventricular function with indication for Impella® 5.5 implantation. With further RV deterioration, a temporary RVAD with a ProtekDuo®canula + CentriMag^TM pump was implanted. The patient was weaned from nitric oxide (NO) inhalation and extubated on the first postoperative day (POD). However, he developed hyperbilirubinemia with Bilirubin > 13 mg/dl under full t-RVAD support and continuous inotrope therapy, with acute-on-chronic renal failure leading to anuria. High urgent listing for transplantation (HTX) was not an option in this clinical situation. The patient gave consent to biventricular assist device (BIVAD) implantation. On POD 19 after pericardiectomy, a HeartMate 3^TM LVAD in a hybrid combination with a Berlin Heart® Excor RVAD was successfully implanted. He was weaned from NO and extubated within 24 hours. On POD 3 after BIVAD, a right ventricular chamber upgrade to a 80ml chamber was performed. After 4 weeks on BIVAD support, the patient developed a haemothorax with need for surgical revision due to overanticoagulation. Thereafter, he slowly recovered and could be discharged from ICU to the normal care ward after 92 days. He has been free from dialysis since 11/2020 and was discharged home with a Berlin Heart®Excor mobile in 12/2020. Active listing for HTX was granted in 06/2021, one year after first admission. The patient is now stable in NYHA 3 with BIVAD support at home. <h3>Summary</h3> Treatment options in biventricular failure are limited. In countries with long waiting list time, hybrid BIVAD support with a continuous flow LVAD and a pulsatile paracorporeal RVAD is feasible and allows successful discharge. Further research is needed to evaluate this clinical approach.

Continuous Flow Paracorporeal Support in Children: A Single Center Experience

<h3>Purpose</h3> Ventricular assist device (VAD) support in small children with end-stage heart failure remains challenging with limited device options. Pulsatile paracorporeal VADs (PP) have long been the mainstay for this group, however outcomes in continuous flow (cf) VADs suggest a beneficial mode of support with consistent physiology between intra- and paracorporeal cfVADs (PC). We sought to describe our center's experience in universal use of PC without transition to PP after the early high risk period. <h3>Methods</h3> We performed a single center retrospective review of all pediatric systemic PC implants from 2017-2021. We evaluated adverse event (AE, ACTION-defined) frequency and rates as well as device outcomes (alive on support, explant, transplant, or death). <h3>Results</h3> Overall 28 PC implants were performed: 24 Pedimag, 4 Centrimag. Patients were predominantly young with median age 0.9 yrs [0.26, 1.74], small with median BSA 0.41 m² [0.29, 0.51], male (65%), with a diagnosis of DCM (11 DCM, 4 Myocarditis, 3 "other" cardiomyopathy, 10 CHD including 6 SV failure), and equally Pedimacs profile 1 and 2 at implant (13-profile 1 and 2, 2-profile 3). Device strategies were bridge to transplant (71%), candidacy (21%), or recovery (7%); and 9 patients (32%) required BiVADs. Median duration of support was 29 days (range 1-544 days). The most frequent AEs were bleeding and infection (both with 9 events, 16.8 per 100 patient-months). Three patients suffered ischemic strokes over the study period (3.75 per 100-pt mo). Outcomes included 1 (3%) alive on support after 544 days and on-going, 5 (18%) explant, 17 (61%) transplant, and 5 (18%) death/compassionate deactivation representing an 82% positive outcome. All deaths were among very high risk patients (SV, <3.5 kg, and biventricular peritransplant failure). <h3>Conclusion</h3> This study represents the largest single center experience of pediatric PC support. Comparisons of PP and PC support to date have largely been from aggregated registry data showing PC support to be inferior, however these data depict PC patients to be composed of higher risk cohorts (congenital heart disease mostly with SV physiology and Pedimacs profile 1). This analysis suggests PC support can provide outcomes similar if not superior to PP support allowing centers to safely support high and low risk patients with consistent cfVAD physiology across the full breadth of the pediatric heart failure spectrum.

Pre-Operative Planning to Mitigate Risk in Complex Single Ventricular Assist Devices

<h3>Introduction</h3> Infants with single ventricle (SV) anatomy are a high-risk group for ventricular assist device (VAD) support. Hybrid stage 1 palliation can be utilized to successfully bridge SV patients to transplantation, such as in the setting of atrioventricular valve regurgitation (AVVR) which precludes long-term SV palliation. Our case highlights how comprehensive pre-procedural planning can mitigate future risk of VAD implantation. <h3>Case Report</h3> A neonate with unbalanced right-dominant atrioventricular canal presented with severe AVVR and acute kidney injury (AKI) precluding traditional SV palliation. She underwent hybrid palliation as bridge to transplant. A 6 mm expandable PTFE graft was anastomosed to the pulmonary artery (PA); ductal stenting was performed through the graft which was then left <i>in situ</i>. She stabilized following initial palliation, but after 10 weeks developed progressive ventricular dysfunction and AKI (Figure 1). A PediMag continuous flow VAD was inserted off bypass using the previous graft for arterial outflow and a right atrial inflow cannula (Figure 2). Renal function recovered and the patient is awaiting transplant with stable hemodynamics. <h3>Summary</h3> Anastomosing a graft to the PA during hybrid palliation enabled placement of VAD off bypass in an infant with SV anatomy and AKI. Detailed pre-operative planning at the time of stage 1 palliation in high-risk infants with potential future VAD support needs may be beneficial as part of a strategy to avoid an early VAD when systemic output is adequate while decreasing subsequent operative risk at time of VAD insertion.

Effects of Pulsatility on Arterial Endothelial and Smooth Muscle Cells

Continuous flow ventricular assist device (CFVAD) support in advanced heart failure patients causes diminished pulsatility, which has been associated with adverse events including gastrointestinal bleeding, end organ failure, and arteriovenous malformation. Recently, pulsatility augmentation by pump speed modulation has been proposed as a means to minimize adverse events. Pulsatility primarily affects endothelial and smooth muscle cells in the vasculature. To study the effects of pulsatility and pulse modulation using CFVADs, we have developed a microfluidic co-culture model with human aortic endothelial (ECs) and smooth muscle cells (SMCs) that can replicate physiologic pressures, flows, shear stresses, and cyclical stretch. The effects of pulsatility and pulse frequency on ECs and SMCs were evaluated during (1) normal pulsatile flow (120/80 mmHg, 60 bpm), (2) diminished pulsatility (98/92 mmHg, 60 bpm), and (3) low cyclical frequency (115/80 mmHg, 30 bpm). Shear stresses were estimated using computational fluid dynamics (CFD) simulations. While average shear stresses (4.2 dynes/cm²) and flows (10.1 mL/min) were similar, the peak shear stresses for normal pulsatile flow (16.9 dynes/cm²) and low cyclic frequency (19.5 dynes/cm²) were higher compared to diminished pulsatility (6.45 dynes/cm²). ECs and SMCs demonstrated significantly lower cell size with diminished pulsatility compared to normal pulsatile flow. Low cyclical frequency resulted in normalization of EC cell size but not SMCs. SMCs size was higher with low frequency condition compared to diminished pulsatility but did not normalize to normal pulsatility condition. These results may suggest that pressure amplitude augmentation may have a greater effect in normalizing ECs, while both pressure amplitude and frequency may be required to normalize SMCs morphology. The co-culture model may be an ideal platform to study flow modulation strategies.

The use of serotonin reuptake inhibitors increases the risk of bleeding in patients with assist devices

BackgroundBleedings are frequent and dreaded complications in heart failure patients with ventricular assist devices (VAD). Serotonin reuptake inhibitor (SRI) antidepressants are widely used to treat depression in these patients, though they are attributed an increased risk of bleeding due to their modification of hemostasis. Evidence on bleeding risk of VAD patients under SRI medication is scarce and limited. We therefore aimed to assess if SRI use is associated with an elevated bleeding risk in this particularly vulnerable population.MethodsWe analyzed the medical records of 92 VAD patients at the University Heart Center Zurich between September 2004 and April 2018 for the occurrence of bleedings and the concomitant use of an SRI. Bleeding was defined as any type of post-implantation bleeding requiring medical treatment. We performed univariate analyses and linear mixed-effects models, adjusting for baseline clinical characteristics as potential predictors to identify differences in bleeding rates in patients with vs. without SRI intake.ResultsThe cohort comprised 60.9% of patients with a continuous-flow VAD and 39.1% with a pulsatile-flow VAD. A total of 77.2% of patients experienced at least one bleeding incident. Overall, 28.6% of bleedings occurred under SRI therapy. A generalized linear mixed model showed a predictive effect of SRI medication on bleeding rate, independent of VAD type (z = 2.091, p = 0.037).ConclusionsBleeding events in heart failure patients occur frequently after VAD implantation. Patients with SRI medication were at increased risk of bleeding. The indication and use of SRI, therefore, should be considered carefully.