Types Of Ventricular Assist Devices Research Articles

Impact of ventricular assist device use on pediatric heart transplant waitlist mortality: Analysis of the scientific registry of transplant recipients database.

Children awaiting heart transplant (Tx) have a high risk of death due to donor organ scarcity. Historically, ventricular assist devices (VADs) reduced waitlist mortality, prompting increased VAD use. We sought to determine whether the VAD survival benefit persists in the current era. Using the Scientific Registry of Transplant Recipients, we identified patients listed for Tx between 3/22/2016 and 9/1/2020. We compared characteristics of VAD and non-VAD groups at Tx listing. Cox proportional hazards models were used to identify risk factors for 1-year waitlist mortality. Among 5054 patients, 764 (15%) had a VAD at Tx listing. The VAD group was older with more mechanical ventilation and renal impairment. Unadjusted waitlist mortality was similar between groups; the curves crossed ~90 days after listing (p = .55). In multivariable analysis, infant age (HR 2.77, 95%CI 2.13-3.60), Black race (HR 1.57, 95%CI 1.31-1.88), congenital heart disease (HR 1.23, 95%CI 1.04-1.46), renal impairment (HR 2.67, 95%CI 2.19-3.26), inotropes (HR 1.28, 95%CI 1.09-1.52), and mechanical ventilation (HR 2.23, 95%CI 1.84-2.70) were associated with 1-year waitlist mortality. VADs were not associated with mortality in the first 90 waitlist days but were protective for those waiting ≥90 days (HR 0.43, 95%CI 0.26-0.71). In the current era, VADs reduce waitlist mortality, but only for those waitlisted ≥90 days. The differential effect by race, size, and VAD type is less clear. These findings suggest that Tx listing without VAD may be reasonable if a short waitlist time is anticipated, but VADs may benefit those expected to wait >90 days.

Outcomes of Intracorporeal Continuous and Paracorporeal Pulsatile Ventricular Assist Devices in Pediatric Patients 10-30 kg.

Ventricular assist devices (VADs) have been increasingly implanted in pediatric patients. Paracorporeal VADs are generally chosen when intracorporeal continuous (IC) devices are too large. Superiority between IC and paracorporeal pulsatile (PP) devices remains unclear in smaller pediatric patients. Our study analyzes outcomes of IC and PP VADs in pediatric patients who could be considered for either of these options. Using the Advanced Cardiac Therapies Improving Outcomes Network (ACTION) database, we identified children between 10 and 30 kg who received a VAD between June 2018 and September 2021. Survival and stroke outcomes were analyzed based on VAD type. There were 41 patients in the IC group and 54 patients in the PP group. Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile at the time of implant was higher in the PP cohort ( p < 0.02). The PP cohort was younger ( p < 0.001) and smaller ( p < 0.001) than the IC cohort. The diagnosis was similar between cohorts. Overall survival was similar between groups. Stroke was more common in the PP cohort, but did not reach statistical significance ( p = 0.07). Discharge was possible only in the IC group, but the discharge rate was low (9.5%). Direct comparisons remain challenging given differences in INTERMACS profiles, age, and size.

PEDS3: Risk Factors for Thromboembolic Events in Pediatric Patients with Ventricular Assist Devices

Background: Pediatric patients on ventricular assist device (VAD) support are at risk of thromboembolic (TE) complications which include pump thrombosis, ischemic stroke, and transient ischemic attack. Methods: We conducted a retrospective chart review of pediatric patients implanted with Paracorporeal Pulsatile (PP) or Paracorporeal Continuous (PC) VADs between 2005-2022, at the Stollery Children’s Hospital (Edmonton, AB). Patients that transitioned from PC to PP were classified in a combination group. Patient and device related factors, including initial anti-coagulation strategies were collected. Kaplan Meier (KM) survival analysis was performed to determine freedom from TE event based on initial anti-coagulation strategy and VAD type. Univariate and multivariate Cox proportional hazard analysis was conducted to look for factors associated with TE events. Results: Of the 95 patients included, median age was 0.92 years (IQR 0.27, 5.37), median weight at implant was 8.4 kg (IQR 4.4, 18.0). Almost two-thirds (63%) had non congenital disease, with 47% supported on PC devices, 25% on PP devices, and 28% with a combination of devices. Initial anti-coagulation was with either Heparin (61.5%) or Bivalirudin (38.5%). Unadjusted freedom from a TE event was significantly higher in those who received Bivalirudin as their initial anti-coagulation strategy (p=0.022, Figure 1). KM analysis based on device type found that PC VADs predicted shorter freedom from TE events (p=0.012). In multivariate analysis, initial anticoagulation strategy (HR 0.359, 95% CI 0.165–0.785, p=0.01) for Bivalirudin was protective against events, while device type (HR 10.9, 95% CI 2.68–44.2, p<0.001), specifically PC devices, was found to be a predictor of TE events. Conclusions: This study suggests that device type, particularly PC, and heparin as an initial anti-coagulation strategy are risk factors TE events. Further work is needed to understand the interaction between device type and initial anti-coagulation strategy.

Outcomes of Intracorporeal Continuous, Paracorporeal Continuous, and Paracorporeal Pulsatile Ventricular Assist Devices in Pediatric Patients 10-30 kg

<h3>Purpose</h3> In the past decade, ventricular assist devices (VADs) have been increasingly implanted in pediatric patients. Although no definitive size standards exist, paracorporeal VADs are generally chosen when intracorporeal continuous (IC) devices are deemed too large for smaller patients. Superiority between IC, paracorporeal continuous (PC) and paracorporeal pulsatile (PP) devices remains unclear in smaller pediatric patients. Our study analyzes outcomes of IC, PC and PP VADs in pediatric patients who could be considered for any of these options. <h3>Methods</h3> Using the Advanced Cardiac Therapies Improving Outcomes Network(ACTION) database, we identified children between 10 and 30 kg who were supported on a VAD between June 2018 and September 2021. Survival and stroke outcomes were analyzed based on VAD type. <h3>Results</h3> Patient demographics, survival outcomes and stroke rates are displayed in Table 1. Patient diagnosis was similar amongst all three cohorts. Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile at time of implant was similar in all groups except when comparing the IC vs PP cohorts (p = 0.03). The PP and PC cohorts were younger (p<0.001) and smaller (p<0.001) than the IC cohort. The number of device days was highest in the IC cohort. Overall survival was similar between groups. Stroke rate was higher in the PP group, but without statistical significance. Discharge was possible only in the IC group, but the discharge rate was low (9.5%). <h3>Conclusion</h3> There was difference in overall survival rates between the IC, PC and PP cohorts. Rates of stroke were highest in the PP cohort, but without statistical significance. Diagnosis and INTERMACS profile were similar with the exception of the IC vs PP cohorts, but direct comparisons remain challenging given differences in age and size. Future studies are needed to compare outcomes in these devices especially given size constraints in smaller pediatric patients.

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.

Safety and Feasibility of Exercise Rehabilitation in Children with Ventricular Assist Devices.

Children with advanced heart failure may require ventricular assist devices (VAD) while awaiting heart transplantation. Currently, no data exist regarding the safety of exercise rehabilitation (ER) in children on VAD support. The purpose of this study was to determine the safety and feasibility of ER in children on VAD support awaiting heart transplantation. Eligible patients underwent VAD placement between 1998 and 2019; both inpatient and outpatient participants were included. After VAD implantation and when ambulatory, patients were enrolled in ER. Exercise sessions were scheduled three times a week and consisted of aerobic and musculoskeletal conditioning. A total of 29 patients (59% male, mean age 14 ± 3.2years) were included with a median VAD duration of 120 ± 109days. Cardiac diagnoses included cardiomyopathy (81%) and congenital heart disease (19%). VAD type included pulsatile (59%) and continuous-flow devices (41%). Eight hundred and sixty-four (85%) ER sessions were successfully completed and began at a mean of 49days (range 19-108) after VAD implant. No adverse events, including episodes of hypotension, significant complex arrhythmia, or VAD malfunction occurred during exercise testing or ER, and no sessions were discontinued prematurely. Pediatric patients on VAD support can safely participate in ER with relatively high compliance, and sessions can be implemented early after VAD implantation. Given the safety profile, ER in pediatric VAD recipients, which is a modifiable pre-transplant risk factor that may improve functional capacity, warrants further study as a potential modality to improve post-transplant outcomes.

Fifth Annual Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) Report

BackgroundThe Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) provides detailed information on pediatric patients supported with ventricular assist devices (VADs). MethodsFrom September 19, 2012, to December 31, 2020, 1229 devices in 1011 patients were reported to the registry from 47 North American Hospitals in patients aged younger than 19 years. ResultsCardiomyopathy was the most common underlying etiology (58%), followed by congenital heart disease (CHD; 25%) and myocarditis (10%). The most common devices implanted were implantable continuous (IC; 419 [41%]), followed by paracorporeal pulsatile (PP; 269 [27%]), paracorporeal continuous (PC; 263 [26%]), and percutaneous (53 [5%]). Overall, at 6 months after VAD implantation, 83% had a positive outcome (transplant, explant, or alive on device). The freedom from stroke at 3 months was highest in IC VADs (93%), compared with PP VADs (84%) and with PC VADs (75%). There were differences in survival by device type, with patients on IC VADs having the best overall survival and those on PC having the lowest overall survival, though the patient populations being supported by each VAD type differed significantly from each other. ConclusionsThis Fifth Pedimacs Report demonstrates the continued robust growth of VADs in the pediatric community, now with more than 1000 patients reported to the registry. The multiple available device types (PC, PP, IC) serve different populations with different pre-VAD risk profiles, which may account for differences in survival and adverse events between device types.

Deciphering Genetic Variants of Warfarin Metabolism in Children With Ventricular Assist Devices.

Warfarin is prescribed in patients with ventricular assist devices (VADs). Dosage depends on several factors including the underlying genotype. These include polymorphisms of genes encoding cytochrome P450 enzymes, the main ones being CYP2C9, VKORC1, and CYP4F2. The objectives of this study were to evaluate the prevalence of CY2CP9 1*2*3*, VKORC1, and CYP4F2 in children with VADs and the time to reach the target international normalized ratio. We performed a retrospective/prospective study in children with VADs. We recorded polymorphisms, disease, type of VAD, ethnicity, age, gender, height, weight, INR values, bleeding, and thromboembolic episodes. Informed consent was obtained. We enrolled 34 children (19 male, 15 female), with a median age of 2years (range 0.3-17years) and median weight of 6.9Kg. The Berlin Heart was the most commonly implanted VAD (22/34; 64%), and the most common diagnosis was dilated cardiomyopathy. Statistical analysis confirmed a significant partial correlation with VKORC1 CC (p = 0.019). The CYP2C9*2 CT genotype showed a late rise in target INR values (p = 0.06), while the CYP2C9*2 CC showed a tendency toward an early INR rise (p = 0.024). We provide new information on the contribution of the warfarin polymorphisms in children with VAD implantation. Pharmacogenomic dosing for children using warfarin has the potential to improve clinical care in VAD patients. Patients with the CYP2C9*2 CT genotype may need more time or higher doses to reach target INR, while clinicians may need to be aware of the potential for a rapid rise in INR in patients with the CYP2C9*2 CC genotype.

Atrial Cannulation in Pediatric Mechanical Circulatory Support

Purpose Several centers have considered the potential benefits of atrial inflow cannulation to provide mechanical circulatory support (MCS) among pediatric patients with small or restrictive ventricles particularly in those with potential for myocardial recovery. Limited pediatric data are available on contemporary outcomes of atrial cannulation. We sought to describe the characteristics, complications, and outcomes of children supported with atrial cannulation using the Advanced Cardiac Therapies Improving Outcomes Network (ACTION) ventricular assist device (VAD) database. Methods Data were collected from the ACTION VAD database for all patients who underwent VAD implantation via atrial cannulation from 8/16/2012 to 9/8/2020. Patient characteristics, VAD types, complications, and outcomes were analyzed. Results Forty-one patients met the study criteria with 52 implants. Median age was 3.6 years (range 0.02 - 25.32), weight 13.6 kg (2.7-106), and BSA 0.6 (0.15 - 2.2). Diagnoses included dilated cardiomyopathy (42%), congenital heart disease (37%), transplant graft dysfunction (7%), restrictive and hypertrophic cardiomyopathies (5% each). VAD indications were bridge to decision (42%), bridge to transplant (42%), and bridge to recovery (17%). Eighty-four percent of patients were INTERMACS 1 or 2, 44% were on ECMO, and 63% were mechanically ventilated. Devices utilized included Berlin Heart Excor (40%), paracorporeal continuous flow devices (38%), Heartware (19%) and one Heartmate 3. Median support duration was 43.5 days (range 0-307). Overall mortality was 22%. Twenty patients (49%) were successfully transplanted, 7 (17%) recovered, and 5 (12%) are still alive on the device. Adverse events included major bleeding (24%), stroke (12%), sepsis (10%), right heart failure requiring RVAD (5%), and one instance of pump thrombosis. Conclusion Atrial cannulation in pediatric MCS can be performed across a variety of anatomic substrates and age ranges with outcomes and complication rates that are comparable to left ventricular cannulation strategies. This method may be advantageous in certain circumstances including patients with small or restrictive ventricles, potential for myocardial recovery, or multiple prior sternotomies to minimize surgical dissection. Further studies are needed to delineate the ideal patient population and benefits of varying atrial cannulation techniques.

Abstract 13291: Impact of VAD Support Duration on Pediatric Heart Transplant Outcomes

Introduction: There is wide variability in the timing of heart transplant (HT) listing and consideration of organ offers after ventricular assist device (VAD) implant in children. While some centers wait weeks or months before proceeding with HT, others accept donor hearts within days of VAD surgery. We sought to determine if HT within 30 days of VAD implant impacts post-HT outcomes when compared to HT after ≥30 days of VAD support. Methods: Patients on VAD support prior to HT were extracted from the Pediatric Heart Transplant Study database. The primary endpoints were post-HT length of hospital stay (LOS) and one-year survival. Confounding was addressed by propensity score weighting using inverse probability of treatment. Propensity scores were calculated based on age at VAD implant, blood type, primary cardiac diagnosis, decade, VAD type, and allosensitization status. Group balance was verified with standardized differences. Results: A total of 1138 children underwent VAD implant prior to HT between 2000-2019 (Table 1). Most underwent HT ≥30 days after VAD (71%). The majority (70%) had an LVAD alone. Infants accounted for 22% of both groups, while those 1-11 years were 46% of the ≥30-day group and patients ≥12 years made up 42% of &lt;30-day group (p=0.001). There was no difference in the prevalence of congenital heart disease vs. cardiomyopathy (p=0.7) or high allosensitization status (p=0.8) between groups. Post-HT LOS was similar between groups (23 vs. 21 days in &lt;30 vs. ≥30 days, p=0.07). One-year survival was 90.5% in the &lt;30-day group vs. 94.5% in ≥30 days (adjusted mortality HR 1.81, 95% CI 1.15-2.86, p=0.01). Conclusions: In this large study of children undergoing HT after VAD, we found lower one-year survival in patients on VAD support for &lt;30 days prior to HT compared to those on VAD for ≥30 days before HT. These findings suggest that a strategy of delayed HT listing following VAD implant may favorably impact post-HT survival in the pediatric population.

Fourth Annual Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) Report

The Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs), originally a National Institutes of Health-sponsored U.S. database, provides a platform to understand the population of children supported with ventricular assist devices (VADs) during this time of increasing numbers, new devices, expanding indications, and improved outcomes. Between September 19, 2012, and December 31, 2019, 44 hospitals implanted 1031 devices in 856 patients under 19 years of age. Overall, diagnosis was cardiomyopathy in 497 (58%) patients, congenital heart disease (CHD) in 216 (25%), myocarditis in 85 (10%), and other in 58 (7%). Positive outcome (alive on device or bridge to transplantation and recovery) occurred in 82% at 6 months. The patient cohort for implantable continuous (IC) pumps (n= 365) (age 13.2 ± 3.9 years, 18% Interagency Registry for Mechanically Assisted Circulatory Support [Intermacs] profile 1, 23% intubated at implantation, 16% with CHD) was significantly different from the paracorporeal continuous (PC) pump cohort (n= 212) (age 3.6 ± 4.9 years, 46% Intermacs profile 1, 81% intubated, 42% CHD) and the paracorporeal pulsatile (PP) pump cohort (n= 230) (age 2.7 ± 3.5 years, 31% Intermacs profile 1, 76% intubated, 26% CHD). Consistent with their cohort composition, positive outcomes at 6 months based on device type were the following: IC, 92%; PC, 68%; and PP,81%. The incidence of cerebrovascular accidents in the IC, PC, and PP cohorts was 7%, 14%, and 15%, respectively. IC VADs, the most common VAD type placed in children, are associated with improved outcomes compared with PP and PC devices, though PP and PC devices are limited to supporting our most challenging patients. Noteworthy, the incidence of cerebrovascular accidents for pediatric VADs has significantly decreased and is now 11% overall. This report demonstrates again that although often attributed to age, size, or device type, much of the burden in mortality and adverse events is correlated to the patient's overall state at VAD implantation.

Designing an Active Valvulated Outflow Conduit for a Continuous-Flow Left Ventricular Assist Device to Increase Pulsatility: A Simulation Study.

The purpose of this work was to investigate, using a lumped parameter model, the feasibility of increasing the pulsatility of a continuous-flow ventricular assist device (VAD) by implanting an active valvulated outflow cannula. A lumped parameter model was adopted for this study. VAD was modeled, starting from its pressure-flow characteristics. The valvulated outflow conduit was modeled as an active resistance described by a square function. Starting from pathologic condition, the following simulations were performed: VAD, VAD and valvulated outflow conduit in copulsation and counterpulsation with different ratios between the VAD valve opening rate and the heart rate, and asynchrony work with the heart with different VAD valve opening intervals. The copulsation 1:1 configuration and the asynchrony 0.3s-close-0.7s-open configurations permit to maximize the hemodynamic benefits provided by the presence of the active VAD outflow valvulated conduit providing an increase of arterial pulsatility from 1.86% to 14.98% without the presence of left ventricular output. The presence of the active VAD valve in the outflow conduit causes a decrement of the left ventricular unloading and of VAD flow and, that can be counteracted by increasing the VAD speed without affecting arterial pulsatility. The valvulated outflow tube provides an increase in arterial pulsatility; it can be driven in different working modality and can be potentially applicable to all types of VADs. However, the valvulated outflow conduit causes a decrement of left ventricular unloading and of the VAD flow that can be counteracted, increasing the VAD speed.

Preliminary Data on the Clinical Use of Infant Jarvik 2015 in Children with Dilated Cardiomyopahty; Recovery Will Be the New Therapeutic Goal?

Continuous flow and intra-corporeal ventricular assist devices (VAD) in children has becoming attractive for their potential benefit in pediatric population. CF VAD for children less than 20 kg are still challenging population. We reported the effect of CF VAD in small children with dilated cardiomyopathy refractory to conventional pharmacological treatment. We implanted CF VAD type Infant Jarvik 2015 (Infant Jarvik 2015 Jarvik Heart, Inc., New York, NY) in 3 consecutive pediatric affected by dilated cardiomyopathy with refractory symptoms of heart failure. The mean weight at implantation was 11 kgs. Primary diagnosis was dilated cardiomyopathies in all. All 3 children survived. In one patient we changed the vad for pump thromboses. The mean time on VAD was 336,7± 105,4 days. All patients were treated with heart failure therapies. In all patient we obtain a significant recovery of LV function with significant reduction of SD LVEDD and increase of ejection fraction more than 45%. One patient was discharged home and is waiting for vad removal. In 2 patients the vad was removed and the mean follow up after removal was 120 ± 63,3 days. No acute episode of heart failure during follow up were recorded. Infant Jarvik 2015 LVAD, the smallest pump available conceived for children, can be successfully implanted in children. The use of continuous flow intracorporeal is feasible in children and from these preliminary results seem to be effective to induce recovery in small children with dilated cardiomyopathy. These data should be validated in future trial.

Gastrointestinal Bleeding as a Complication in Continuous Flow Ventricular Assist Devices: A Systematic Review With Meta-Analysis.

BackgroundThe use of ventricular assist devices (VADs) has become predominant in this era of medicine. It is commonly used as a bridge to transplant, recovery and as a destination therapy for patients with severe heart failure, who are not responsive to maximum optimal management or ineligible for transplant. However, several complications are known to occur with the use of these devices. In this research, we will compare gastrointestinal bleeding in patients who used centrifugal flow versus axial flow VADs. We hope that the result of this meta-analysis and the review presented provide adequate information to future researchers, physicians and other healthcare professionals who are interested in this topic.MethodsPublished articles evaluated for inclusion were obtained from MEDLINE (PubMed), Cochrane, EBSCO, clinicaltrials.gov, and international clinical trials registry. This research was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Procured articles were reviewed by two independent reviewers. Only randomized control trials and observational studies were used. Quality assessment was done with Cochrane Collaboration’s tool (RoB.2 with visualization through robviz) and Newcastle-Ottawa Scale (NOS). Data analysis was carried out with the use of R data analysis tool (version 4.0.0; release date: April 24th, 2020).ResultsAt the end of this meta-analysis, the occurrence of gastrointestinal bleeding was not significantly different between both groups; with odds ratio (OR): 0.81; 95% confidence interval (CI): 0.65 - 1.00; P value = 0.05. Between-study variance (Tau-squared) was zero (0), standard error (SE) = 0.06. The degree of heterogeneity measured with I-squared statistic was 0% (minimal). Egger’s regression test was not statistically significant, P = 0.93. Symmetry of distribution was observed on the funnel plot. Trim and fill analysis showed no missing studies on the left; SE = 1.68.ConclusionsThe result obtained from this research indicates that the occurrence of gastrointestinal bleeding is not significantly different in both groups of patients, irrespective of the type of continuous flow VAD used. Although, the study sample used in this meta-analysis was limited.

1177. A Spectrum of Infectious Complications in Continuous-Flow Ventricular Assist Devices: A Single-Center Longitudinal Cohort

BackgroundInfections remain a frequent complication of patients (patients) with ventricular assist devices (VAD). We evaluated the epidemiology and outcomes of VAD infections at our center over a 10-year period.MethodsWe performed a retrospective cohort study of continuous-flow VAD recipients from July 2008-September 2018. VAD-specific and -related infections were characterized according to 2013 ISHLT definitions. Summary and comparative statistics were performed using IBM® SPSS Statistics version 25.0.Results433 VADs were implanted into 375 patients. A total of 86 VAD infections occurred in 79 patients, with a mean incidence of 0.19 episodes/VAD and 0.20 episodes/pt. Patients with infections were predominantly male (73.3%) and Caucasian (54.6%), and had mean age of 52.7 years, nonischemic cardiomyopathy (58.1%), and VAD as bridge to transplant (53.5%, n = 46). Types of VAD included 43.0% axial (n = 37) and 57.0% centrifugal flow (n = 49). 78% of patients with infections were colonized with at least one multidrug-resistant organism (MDRO) such as MRSA (29%), VRE (73%), and ESBL (24%).Notably, 15% of infections (n = 13) occurred within 60 d of VAD implantation, with mean time to onset 36 d (5–60 d) post-VAD. Early infections (<60d) involved driveline exit site (DLES) (n = 4), pocket (n = 3), and pump (n = 7) with 7 VAD-related blood stream infections (BSI), 6 infective endocarditis (IE), and 2 mediastinitis. Early infections involved Gram-positive (GP) bacteria (84.6%, n = 11), Gram-negatives (GN) (45.5%, n = 5), anaerobes (23.1%, n = 3), fungi (30.8%, n = 4), MDRO (61.5%, n = 8) and 32 pathogens (69.2%, n = 9). 85% of infections occurred late (n = 73) with mean time to onset 338 d (69–1215 d). In late infections (>60d), impacted sites included DLES (n = 38), pocket (n = 7), and pump (n = 40), with 42 BSI, 36 IE, and 2 mediastinitis. Pathogens were 68.5% GP (n = 50), 37.0% GN (n = 27), 2.7% anaerobes (n = 2), 2.7% fungi (n = 2), 17.8% MDRO (n = 13), and 26.0% polymicrobial (n = 19).ConclusionIn this longitudinal retrospective cohort of patients supported with VADs, a majority of infections occurred >9 months post-implantation. GP pathogens predominated at all time-points. GN bacteria, including MDROs, anaerobes, and fungi are increasingly encountered. The vast majority of patients were colonized with ³1 MDRO during the course of VAD implantation.Disclosures All authors: No reported disclosures.

A numerical analysis on different-generation prototypes of ventricular assist device

The ventricular assist device (VAD) assists the patients with heart diseases for limited and prolonged periods. This device synchronizes with normal heart activities to help foster its performance. Consequently, its sensitive design requires high accuracy. The pumps are the essential part of every VAD which should operate in wide ranges of flow and pressure. As there are various types of VAD under different designs, it is neither practical nor plausible to experimentally/clinically investigate their performances. Therefore, in the concurrent study, a numerical study was carried out on four different generation prototypes of VAD pumps for reaching an optimum design. Using computational fluid dynamics (CFD) method, the software derived, showed and streamlined the flow field shear stress both inside the VAD and its blades. Furthermore, the vortices and flow rate-pressure curves were observed. The results showed that the curved blade pumps operate better compared to that of the straight blade types, concerning the provision of enough pressure and less damage to the red blood cells. The results have implications not only for comparing different types of VAD designs but also for understanding the resulted shear stresses and pressures as a result of the blade’s structure.

Association between AT1R Autoantibody with Adverse Outcomes in Patients Bridged to Heart Transplant Using Continuous Flow Ventricular Assist Device

Purpose Antibody to angiotensin-II type 1 receptor (AT1R-Ab) may be implicated in allograft dysfunction in patients who are bridged to heart transplant (BTT) with a continuous flow left ventricular assist device (VAD). We studied AT1R-Ab level following VAD implantation on event-free survival in BTT patients and whether AT1R-Ab elevation is independent from inflammation as measured through C-reactive protein (CRP). Methods Sera of 77 BTT patients from 2009 to 2017 were tested for AT1R-Ab and CRP prior to and after VAD placement. Elevated AT1R-Ab level was defined as greater than 10.0 U/mL. For statistical analysis, the value of 40 U/mL was assigned to AT1R-Ab level greater than 40 U/mL. Events were defined as acute cellular rejection, antibody-mediated rejection, cardiac allograft vasculopathy, reduced EF, and death. Results Median follow-up time after transplant was 3.3 years (range 0.4-9.0 years). After VAD implantation, AT1R-Ab was increased as compared to baseline (Fig 1A). Univariate regression analysis revealed that age, female gender, African-American race, time to transplant, type of VAD, HLA sensitization, and positive donor specific antibodies were not risk factors for AT1R-Ab sensitization. The elevated post-VAD AT1R-Ab cohort had more events than the normal AT1R-Ab group (61% vs 29%, Fig 1B). On Kaplan Meier analysis, there was a statistically decrease in 5-year event-free survival in patients who had elevated AT1R-Ab levels (Fig 1C). Multivariate Cox regression analysis showed increased post-VAD AT1R-Ab as an independent risk factor for developing events. Though CRP was high before and after VAD implantation, CRP had no statistically significant correlation with AT1R-Ab level (Fig 1D). Conclusion Increase in AT1R-Ab was seen in BTT patients after VAD implantation and was associated with adverse outcomes after heart transplant. The AT1R-Ab elevation does not appear to be an epiphenomenon related to CRP, a marker of inflammation.

Anti-Coagulation Management in Pediatric Ventricular Assist Device: A Quality Improvement Target

Purpose Pediatric Ventricular Assist Device (VAD) therapy is associated with high rates of stroke and bleeding. There have been limited efforts to date, to define and implement optimal anticoagulation (AC) strategies in this population. ACTION (Advanced Cardiac Therapies Improving Outcomes Network) is the first pediatric VAD quality improvement network, with an initial goal of stroke reduction. This report describes baseline AC data from ACTION centers, including agents used and aggregate levels of performance, to inform development of specific interventions. Methods The AC practices of ACTION centers were assessed. Data collected included VAD type, weekly data characterizing AC agents used; time to achieve desired levels; and percentage of levels within the desired range. Results Data were collected from 11 centers, with a total of 30 patients. AC data were collected from 6/1-9/1/18, while strokes were collected retrospectively for the entire VAD support interval. Devices included: HVAD (12); EXCOR (10); Heartmate 3 (3); and 5 paracorporeal continuous flow devices. There were 5 strokes (16.7%). Intravenous AC included unfractionated heparin (36%), and bivalirudin (64%). There was wide variability between patients in the time to achieve first therapeutic AC level (Figure 1), with 15 patients at goal within 20 hours, while others required up to 170 hours. Heparin levels varied widely, with the percent of labs within range falling below 50%, in 50% of the weeks reported. For bivalirudin, levels were less variable, with percent of labs within range falling below 50% in only 14% of weeks reported. Conclusion At baseline, stroke rates remain high in the ACTION centers. Intravenous AC includes both heparin and bivalirudin, with high variability in time until therapeutic levels are achieved, and with high variability in subsequent levels, particularly for heparin. These data will inform interventions designed to reduce variability in AC performance as a basis for stroke reduction.

Third Annual Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) Report: Preimplant Characteristics and Outcomes

The influence of ventricular assist device (VAD) use in the care of children with end-stage heart failure is growing rapidly through increasing numbers, new devices, expanding indications, and improving outcomes. Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs), a National Institutes of Health-sponsored United States database, provides a platform to understand this emerging population. Between September 19, 2012, and December 31, 2017, 30 hospitals implanted 508 devices in 423 patients aged younger than 19 years. This past year was one of evolution for the database as its management was transitioned to The Society of Thoracic Surgery; therefore, this report does not include data from institutions not under contract by August 1,2018. Of the 423 patients, the diagnosis was cardiomyopathy in 261 (62%), myocarditis in 48 (11%), other in 28 (7%), and congenital heart disease (CHD) in 86 (20%), with 52 of these patients having single-ventricle physiology. The two most common support strategies included left VAD in 342 (81%) and biventricular assist device in64 (15%). Positive outcome (alive on device or bridge to transplantation/recovery) was 80% at 6 months (overall mortality of 20%). The patient cohort for implantable continuous-flow (IC) pumps (n= 197; age at implant, 13.4 ± 3.8 years; 19% Interagency Registry for Mechanically Assisted Circulatory Support [Intermacs] profile 1, 21% intubated at implant, and 12% with CHD) was significantly different from the paracorporeal continuous-flow (PC) pump cohort (n= 79; age, 3.9 ± 5.2 years; 49% Intermacs profile 1, 86% intubated at implant, and 38% with CHD) and the paracorporeal pulsatile (PP) pump cohort (n= 121; age, 3.3 ± 3.9 years; 41% Intermacs profile 1, 77% intubated at implant, and 21% with CHD). Consistent with their cohort composition, device type positive outcomes at 6 months were PC, 63%; PP, 77%; and IC, 92%. Parametric hazard modeling showed an early hazard for death was associated with Intermacs profile 1, biventricular assist device, percutaneous devices, PC devices, small-volume institutions, low age, and low weight, whereas a constant hazard was associated with intubation and liver dysfunction at time of implant. IC VADs are the most common VAD type placed in children. The positive outcomes for the IC VADs exceed 90% at 6 months, which may represent our field's maturation in both patient selection and timing of implantation. The PP/PC devices are currently limited to supporting our most challenging patients, those weighing less than 20 kg and those with CHD. The introduction of new devices and our communities' commitment to shared learning and improvement will lead to more pediatric lives saved by VAD support and will also focus on improving the quality of life of children supported with VADs.

Ventricular Assist Device Support: Single Pediatric Institution Experience Over Two Decades

We reviewed our single institutional experience with pediatric ventricular assist device (VAD) support over the last 2 decades, with an aim to improve our current management and gain an insight into the future direction. A retrospective review was conducted on all patients that had undergone VAD support between 1996 and 2017. Outcomes were analyzed based on the type of VADs, whether temporary or durable devices. Primary end points were positive outcomes, including bridge-to-transplantation, bridge-to-recovery, alive on device, and bridge-to-bridge to another VAD, or negative outcomes, including death during VAD support or in-hospital death after bridge-to-recovery. The Pediatric Interagency Registry for Mechanical Circulatory Support definition was used to classify adverse events. Overall, 201 VADs were implanted in 159 patients, with 82 (41%) and 119 (59%) being temporary and durable support, respectively. There has been a trend toward an increasing annual implant volume both with temporary and durable VADs. Positive outcomes were achieved in 80% (66 of 82) of those with temporary support, with bridge-to-recovery (53% [35 of 66]) and bridge-to-bridge to another VAD (38% [25 of 66]) being the predominant outcomes. Of those on durable support, 84% (100 of 119) achieved positive outcomes, with bridge-to-transplant (66% [78 of 119]) being the leading destination. The most notable change during the study period was the introduction of implantable continuous-flow VADs, resulting in outpatient management becoming a routine practice. No patients were discharged on VAD support before 2004, but 85% were discharged on VADs with discharge capability after2013. The present study has demonstrated the evolutional changes of pediatric VAD support and their effect on clinical outcomes over the last 2 decades.