Paracorporeal Ventricular Assist Device Research Articles

Nutritional status and cannula infections in pediatric patients on ventricular assist device support.

Ventricular assist devices (VADs) are used to bridge pediatric patients to heart transplantation. Paracorporeal VADs require the placement of cannulas, which can create an environment for infections. We examined cannula infections in pediatric VAD patients and the role of nutritional status. This retrospective study (2005-2021) included patients <20 years old on VAD support using Berlin Heart EXCOR® cannulas. Cannula infections were defined by a positive culture and need for antibiotic therapy. Malnutrition was defined using the American Society of Parenteral and Enteral Nutrition guidelines as well as the Michigan MTool. There were 76 patients with a median age at implant of 0.9 years (IQR 0.4, 3.6), 50% male, with 73.7% having non-congenital heart disease. More than one-quarter (26.3%) of patients developed a cannula infection. Higher pre-implant weight (OR = 1.93, p = 0.05), creatinine (OR = 1.02, p = 0.044), and pre-albumin (OR = 15.79, p = 0.025), as well as duration of VAD support (OR = 1.01; p = 0.003) were associated with increased odds of developing a cannula infection. There was no difference in the malnutrition parameters between those with and without an infection. Further exploration in a larger cohort is needed to see whether these associations remain and if the incorporation of objective measures of nutritional status at the time of infection are predictive.

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.

Argatroban Use in Pediatric Patients Supported by Paracorporeal Ventricular Assist Devices.

Direct thrombin inhibitor (DTI) use has been associated with decreased stroke and death rates in children on ventricular assist devices (VADs). Most information about DTI use for children on VADs has focused on bivalirudin with limited data on argatroban. We hypothesized that, compared to unfractionated heparin (UFH), argatroban would be associated with decreased bleeding, stroke, and death rates in children on VADs. We retrospectively collected data from patients <18 years old on paracorporeal VADs at Children's Wisconsin between January 1, 2010 and July 1, 2021. We divided patients into cohorts based on anticoagulation strategy with heparin or argatroban. Definitions of bleeding and neurologic events were the same as in other published reports on this population. We compared categorical variables with the χ 2 or Fisher's exact test, and continuous variables with the Mann-Whitney U test. Nineteen children were anticoagulated with argatroban, and 16 with heparin. Demographics between groups were not significantly different. Stroke, bleeding, and death rates did not differ between patients treated with UFH versus argatroban. The study population was complex with a high rate of extracorporeal membrane oxygenation (ECMO) use before VAD support, which likely impacted our findings. Our study does not support argatroban as a superior alternative anticoagulant compared to UFH in children requiring VADs.

(11) A Novel Mobile Driving System Improves the Quality of Life of Children Treated with a Paracorporeal Ventricular Assist Device

(11) A Novel Mobile Driving System Improves the Quality of Life of Children Treated with a Paracorporeal Ventricular Assist Device

Support with Single Ventricle-Ventricular Assist Device (sVAD) in Patients with Functionally Univentricular Circulation Prior to Fontan Operation.

Some patients with functionally univentricular circulation develop cardiac failure refractory to maximal management and are supported with a ventricular assist device (VAD). The purpose of this manuscript is to summarize our previous publications related to single ventricle-ventricular assist device (sVAD) support in patients with functionally univentricular circulation and to describe our current institutional approach at University of Florida to sVAD support in neonates, infants, and children prior to Fontan. Our programmatic philosophy at University of Florida is to strive to identify the minority of neonates with functionally univentricular circulation who are extremely high-risk prior to initiating staged palliation and to stabilize these neonates with primary preemptive sVAD in preparation for cardiac transplantation; our rationale for this approach is related to the challenges associated with failed staged palliation and subsequent bail-out sVAD support and transplantation. A subset of extremely high-risk neonates and infants with functionally univentricular ductal-dependent circulation undergo primary preemptive sVAD insertion and subsequent cardiac transplantation. Support with VAD clearly facilitates survival on the waiting list during prolonged wait times and optimizes outcomes after Norwood (Stage 1) by providing an alternative pathway for extremely high-risk patients. Therefore, the selective utilization of sVAD in extremely high-risk neonates facilitates improved outcomes for all patients with functionally univentricular ductal-dependent circulation. At University of Florida, our programmatic approach to utilizing sVAD support as a bridge to transplantation in the minority of neonates with functionally univentricular circulation who are extremely high-risk for staged palliation is associated with Operative Mortality after Norwood (Stage 1) Operation of 2.9% (2/68) and a one-year survival of 91.1% (82/90) for all neonates presenting with hypoplastic left heart syndrome (HLHS) or HLHS-related malformation with functionally univentricular ductal-dependent systemic circulation. Meanwhile, at University of Florida, for all 82 consecutive neonates, infants, and children supported with pulsatile paracorporeal VAD: Kaplan-Meier survival estimated one year after VAD insertion = 73.3% (95% confidence interval [CI] = 64.1-83.8%), and Kaplan-Meier survival estimated five years after VAD insertion = 68.3% (95% CI = 58.4-79.8%). For all 48 consecutive neonates, infants, and children at University of Florida with biventricular circulation supported with pulsatile paracorporeal VAD: Kaplan-Meier survival estimated one year after VAD insertion = 82.7% (95% CI = 72.4-94.4%), and Kaplan-Meier survival estimated five years after VAD insertion = 79.7% (95% CI = 68.6-92.6%). For all 34 consecutive neonates, infants, and children at University of Florida with functionally univentricular circulation supported with pulsatile paracorporeal sVAD: Kaplan-Meier survival estimated one year after VAD insertion = 59.7% (95% CI = 44.9-79.5%), and Kaplan-Meier survival estimated five years after VAD insertion = 50.5% (95% CI = 35.0-73.0%). These Kaplan-Meier survival estimates for patients supported with pulsatile paracorporeal VAD are better in patients with biventricular circulation in comparison to patients with functionally univentricular circulation both one year after VAD insertion (P=0.026) and five years after VAD insertion (P=0.010). Although outcomes after VAD support in functionally univentricular patients are worse than in patients with biventricular circulation, sVAD provides a reasonable chance for survival. Ongoing research is necessary to improve the outcomes of these challenging patients, with the goal of developing strategies where outcomes after sVAD support in functionally univentricular patients are equivalent to the outcomes achieved after VAD support in patients with biventricular circulation.

PEDS5: Single-Center Experience Improving Nutritional Outcomes in Pediatric Paracorporeal Ventricular Assist Device Recipients

PEDS5: Single-Center Experience Improving Nutritional Outcomes in Pediatric Paracorporeal Ventricular Assist Device Recipients

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.

Impact of Cangrelor Use in Children Supported on Paracorporeal Ventricular Assist Devices

<h3>Purpose</h3> Paracorporeal ventricular support devices (pVAD) are increasingly utilized in pediatric patients with end-stage heart failure as either bridge to recovery or as bridge to heart transplant. Unfortunately, thromboembolic events are not uncommon with use of pVAD with neurologic dysfunction occurring in 15-18% of patients. The optimal antithrombotic regimen is a subject of ongoing study. Cangrelor is an intravenous P2Y12 inhibitor used in adult patients undergoing percutaneous coronary intervention; its pharmacokinetic properties, including intravenous administration, short half-life, and avoidance of cytochrome p450 pathway, make it appealing as a safe and effective platelet inhibitor. We describe our pediatric experience with cangrelor anti-platelet therapy utilized throughout the duration of pVAD support. <h3>Methods</h3> Single-institution, retrospective chart review was conducted on all patients in a tertiary medical center with end-stage heart failure (INTERMACS level 1 or 2) supported with pVAD and receiving cangrelor infusion between June 2019 and October 2021. <h3>Results</h3> Seven patients were supported on continuous pVAD, and two were subsequently transitioned to pulsatile paracorporeal VAD. Median age was 8 months, and median weight was 6.7 kg. Four patients had a diagnosis of complex congenital heart disease. Three patients had dilated or restrictive cardiomyopathy, one of whom was admitted with fulminant myocarditis. Median number of days of continuous VAD support was 24.5 days (IQR 9-64 days). Cangrelor was initiated within 24 hours post-implant at a dose of 0.1 mcg/kg/min. Median time to therapeutic P2Y12 was 18 hours (IQR 13-32), and median duration of cangrelor therapy was 24 days. Mean dose to maintain therapeutic level was calculated, with a median of 0.25 mcg/kg/min (IQR 0.12-0.41 mcg/kg/min). Mean P2Y12 level was 169 PRU. Neurologic complications were encountered in one patient who died following hemorrhagic stroke. One patient experienced a GI bleed. <h3>Conclusion</h3> Cangrelor is safe and effective for use as a long-term antithrombotic medication in pediatric patients supported on pVAD. The frequency of adverse events was similar to that in previously published registry studies. The reliability of its intravenous administration and its short half-life make it appealing as an alternative to oral anti-platelet agents.

The Initial Analysis of Infectious Adverse Events in Pediatric Ventricular Assist Devices Reported to the ACTION Registry

<h3>Purpose</h3> Infection adverse events (IAE) are frequent in pediatric ventricular assist device (VAD) patients. In this study we aim to describe IAE in pediatric VAD patients from the Advanced Cardiac Therapy Improving Outcome Network (ACTION) multi-center registry. <h3>Methods</h3> VAD data from the ACTION registry (9/2018 to 8/2021) were analyzed. Cohort was divided by device type as paracorporeal (PC) (Berlin EXCOR, Pedimag, Centrimag, Rotaflow) and intracorporeal (IC) (Heartware (HVAD), Heartmate3 (HM3), Heartmate2, Syncardia). IAE rates and incidence per 100 patient months were described with descriptive statistics and compared between groups by chi-square test. <h3>Results</h3> Of the 506 patients, 139 patients (27.5%) experienced at least one IAE. Majority were sepsis (77, 34.5%) or localized non device related (77, 34.5%), 51 (22.9%) being IAE of percutaneous site and only 4 (1.8%) were pump related. Median time to first device related IAE was 40 days [6 - 1648]. Infections were bacterial in 121 (46.5%), fungal in 10 (3.86%) and unknown in 119 (46%). Upon comparison, patients on PC devices were significantly younger (0.81 vs 15.2 years), smaller (0.39 vs 1.46 m²), and sicker (INTERMACS profile1 and 2, ECMO at implant and ventilator support; all <i>p</i> values <0.05) than patients on IC. There was no difference in gender, diagnosis, and dialysis frequency between devices. PC devices had a significantly higher IAE rate and had significantly more sepsis IAE (Table). Device related IAE were significantly higher in HM3 than HVAD [17 (47.2%) vs 7 (17.9%); <i>p</i>= 0.019; IAE/100 patient months=2.58 vs 1.02; <i>p</i>= 0.007], which seem to be driven by driveline infections (IAE/100 patient months=2.28 vs 1.02; <i>p</i> =0.028) <h3>Conclusion</h3> A significant proportion of children on VAD experienced IAE, the majority of which are not device related. PC VAD had a higher risk of IAE than IC VAD. Within IC devices, there was a significantly higher rate of driveline site infections in HM3 patients.

Excellent Long-Term Survival After Weaning from Durable Ventricular Assist Device

<h3>Purpose</h3> It is reported that bridge to recovery was achieved in a limited number of cases after durable ventricular assist device (VAD). Thus, long-term survival over 5 years after removal of the device is not thoroughly examined. We aim to analyze long-term results and the trend of left ventricular (LV) function after weaning from a durable VAD in our hospital. <h3>Methods</h3> Since September 2006, 344 durable VAD implantations were performed in the University of Tokyo Hospital, among which 30 patients were successfully weaned from the device. Twenty-five patients were enrolled in this study after excluding 5 patients who were treated for fulminant myocarditis. The majority of causative disease was idiopathic dilated cardiomyopathy in 24. They were implanted with paracorporeal (n = 12) or implantable (n = 13) VAD according to a reimbursement policy. Aggressive pharmacological treatment including titration of beta-blocker and ACE inhibitor or ARB along with aerobic rehabilitation was planned in all cases. Once a sign of functional recovery was recognized, our weaning protocol was initiated, such as cardiopulmonary exercise testing, VAD off-test and volume challenging test. Twenty-five patients met the weaning criteria, and underwent a VAD removal via redo median sternotomy. Long term survival was examined including repeated VAD implantation. Analysis of LV diastolic dimension and ejection fraction by echocardiography and BNP level was conducted to monitor LV function. <h3>Results</h3> Patients were weaned from the VAD after 333-day-long support without in-hospital death. All patients were followed-up for an average of 6 years. One-, 5-, and 10-year survival was 100%, 89.7% and 89.7%, and re-VAD-free survival was 91.8%, 85.7% and 85.7%, respectively. Notably, there was no death in patients who were weaned from implantable VAD. LVDd (67.7 mm) was significantly reduced before weaning (52.3 mm) and stabilized for a year. LVEF (19.5%) was significantly improved before weaning (43.4%) and further increased toward 1 year. BNP was significantly reduced before weaning and in the same level at 1year. <h3>Conclusion</h3> Long-term prognosis of patients who were weaned from durable VAD through our structured protocol was excellent. Bridge to recovery seems to aggressively be reappraised as a vital choice for durable VAD treatment.

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.

Nutritional Status and Cannula Infections in Pediatric VAD Patients

<h3>Purpose</h3> Ventricular assist devices (VADs) have emerged as an effective treatment option to bridge pediatric patients to heart transplantation. Paracorporeal VADs require the placement of an inflow and outflow cannula, which can create an environment for infections. We aimed to characterize cannula infections in pediatric VAD patients and examine the impact of nutritional status. <h3>Methods</h3> This was a single-center retrospective study (2005-2020) of all patients <20 years old implanted with a VAD using Berlin Heart cannulas. A cannula infection was defined by symptoms in the presence of a positive culture and the need for antibiotic therapy. Malnutrition was defined as per the ASPEN guidelines. <h3>Results</h3> There were 54 patients eligible for the study. The median age at implant was 0.9 years (IQR 0.3, 4.1), 59% were male, with the most common etiology being non-congenital heart disease (67%). The median time on VAD support was 89.5 days (IQR 34.3, 174.8). During the study period, 29.6% of patients developed a cannula infection with a median time to infection of 52 days (IQR 23.3, 109.0). There was no difference in terms of pre-VAD weight, height, malnutrition scores, BMI or albumin levels between patients with and without a cannula infection. However, lower pre-VAD pre-albumin levels was associated with cannula infections (p=.022), as was older age (p=.048). Seventy-five percent (n= ¾) of the patients with a g-tube developed a cannula infection and almost 75% of patients who developed a cannula infection were malnourished based on their pre-VAD weight z-scores. <h3>Conclusion</h3> Less than one-third of pediatric VAD patients with Berlin cannulas developed a cannula infection. Pre-VAD pre-albumin levels and older age were associated with the development of a cannula infection. In addition, the majority of the children with an infection were malnourished, suggesting that pre-implant nutritional status may be a modifiable risk factor. These results suggest a relationship between nutritional status and infection that warrants further study in the pediatric VAD population.

The Best Paracorporeal Ventricular Assist Device Strategy in Children? Remains Unanswered

In this issue of The Annals of Thoracic Surgery, the article by Sughimoto and colleagues1 astutely analyzes paracorporeal ventricular assist device (VAD) strategies in the pediatric heart failure population. The study period, 2005 to 2019, is a key time period in the development of the pediatric VAD field. In the beginning of this time period, the Berlin Heart EXCOR, a paracorporeal pulsatile (PP) device, began to have significant growth in clinical use in the United States. There were also sporadic reports of paracorporeal continuous (PC) devices in children before this period, mostly as a bridge to recovery for patients with postcardiotomy ventricular dysfunction, myocarditis, or acute rejection.

Characterization of Strokes in Children on Ventricular Assist Devices: An Action Collaborative Analysis

Purpose We sought to characterize strokes in children supported with ventricular assist devices (VADs) in the Advanced Cardiac Therapies Improving Outcomes Network (ACTION). Methods All patients entered in the ACTION registry (4/1/2018-6/8/2020) were included. Stroke was defined by pre-specified criteria and categorized as hemorrhagic or ischemic in etiology. All strokes were adjudicated by the data coordinating center and the adjudication committee which is comprised of members from multiple sites. Results Of 270 patients in the ACTION registry, 26 patients (9.6%) experienced 28 strokes (25 ischemic and 3 hemorrhagic). Of these 26 patients, 12 (46%) were ≤1yo, 12 (46%) had congenital heart disease, 8 (26%) had preimplant ECMO use, 23 (88%) were on paracorporeal VADs and 3 (15%) had intracorporeal VADs. The median time to stroke was 17.5 days. There were 11 (39%) and 17 (60%) strokes that occurred within 7 and 30 days, respectively, and all strokes occurring ≤30 days post-implant were ischemic. On paracorporeal VADs, there were 23 ischemic (EXCOR=9, Centrimag=6, Pedimag=6, Rotaflow=2) and 2 hemorrhagic (EXCOR=1, Centrimag=1) strokes. With intracorporeal support there were 2 ischemic (HVAD=1, HM3=1) and 1 hemorrhagic (HVAD=1) strokes. The overall stroke rate was 145.4 per 10,000 patient-days. Mortality rates were significantly higher for patients who did (10/26; 38.5%) vs. those who did not (32/144; 13.1%) experience a stroke (p Conclusion Although the stroke rate in children on VADs has decreased over time, strokes still occur in 1/10 patients and are associated with significantly increased mortality. The large majority of strokes are ischemic in nature, associated with paracorporeal VADs, and occur within the first 30 days after implant. About half of the children experiencing strokes on a VAD are ≤1yo and/or have congenital heart disease. Based on these data, ACTION is focusing ongoing quality improvement projects on decreasing strokes for children on paracorporeal devices with particular attention to the early post-implant period.

Outcomes of Infants and Children with Stage 1 Single Ventricle Implanted with Ventricular Assist Devices: An Analysis of the Advanced Cardiac Therapies Improving Outcomes Network (ACTION) Registry

<h3>Purpose</h3> Ventricular assist device (VAD) use in patients with congenital heart disease is increasing. Data on VAD outcomes in infants/children with stage 1 single ventricle (SV) are limited. Our study aims to characterize the outcomes of this population using multi-center registry data. <h3>Methods</h3> We examined the Advanced Cardiac Therapies Improving Outcomes Network (ACTION) registry for outcomes of stage 1 SV patients undergoing VAD implantation between March 2018 - June 2020. ACTION data are collected from 30 centers, and major adverse events undergo central adjudication using pre-specified event definitions. Clinical characteristics, major adverse events, and survival are reported. <h3>Results</h3> During the study period, 27 stage 1 SV patients underwent VAD implant with median age of 1 month (range 0.1-44), weight 3.7kg (2.4-17), and BSA 0.24 m² (0.18-0.65). Pre-implant comorbidities were frequent: ventilator support (85%), ECMO (37%), history of cerebral vascular accident (CVA, 30%), and pre-implant dialysis (18.5%). Device strategy included paracorporeal continuous-flow VAD in 11 patients, paracorporeal pulsatile VAD (12), and multiple devices (4). Concomitant surgical procedure was performed in 4 patients. Median support duration was 56 days (2-271). A positive clinical outcome, defined as transplant, weaned, or alive on device was obtained in 59%, with 12 patients transplanted while 11 died on device (Fig 1). Adverse events on VAD support included neurologic dysfunction (18.5%, with n=2 CVA), bleeding (22%), infection (48%), renal dysfunction (15%), and device malfunction (4%). <h3>Conclusion</h3> Stage 1 SV patients undergoing VAD support have frequent and severe pre-implant comorbidities, which likely contributed to the significant morbidity and mortality post-implant. A variety of device types and surgical strategies are employed by centers to support this challenging physiology.

Early Clinical Experience of a Novel Mobile Driving Unit for Pediatric VAD Support

Purpose Recently, a novel mobile driving unit (MDU) of the only approved pediatric ventricular assist device (VAD) system for both short- and long-term support of children of all sizes and ages received market approval. The MDU was specifically developed to improve mobility and autonomy of children supported with this paracorporeal (pc) VAD. This case series collects initial information with the aim to assess the first clinical experience. Methods A retrospective case series gathered anonymized patient health data of pediatric patients supported with MDU. The usability was assessed by means of a patient standardized questionnaire (numerical scale, 1= worst to 5= best). Results From February 2020 until September 2020, eight children (3 females) have been supported with a pc VAD in combination with the MDU. The median age was 1.4 years (range 0.5 - 7.5), median body surface area 0.4 m2 (0.3 - 0.9). Primary diagnosis was cardiomyopathy (CM) in 7 patients (5 dilated and 2 restrictive CM), and congenital heart disease in one child. Five patients (62.5%) received a pc VAD as left-sided and two patients as biventricular support (BVAD, 25%). One had a secondary right-sided pc VAD in combination with an implantable left-sided centrifugal VAD. The distribution of pc pump chambers by size was 10 ml pump: 2 patients (25%), 15 ml pump: 4 subjects (50%) and 30 ml pump: 2 children (25%), plus 15 ml pumps in both pc BVAD patients. The mean time of VAD support was 406 ± 241 days, with 148 ± 76 days on MDU. At the end of the observational period, 5 patients (62.5%) were still on system, 2 (25%) were transplanted and 1 died (12.5%) for causes not related to the driving unit. The survey found increased mobility (score 4.2/5), enlarged activity radius (5/5) and reduced noise nuisance (4.5/5) with MDU in comparison to the stationary unit. There were no complaints in MDU handling reported and the easiness to use was rated (4.5/5). In addition the parents reported a significant less heat generation by the MDU. The safety profile of MDU showed five adverse events: one fatal case (12.5%), one respiratory failure (12.5%), both not device-related, and two pump malfunctions (25%). One patient (12.5%) underwent pump replacement due to fibrin debris. Conclusion The case series suggests that the novel MDU is safe and effective for VAD support in the pediatric population. It is likely that MDU will increase the quality of life in this cohort.

Pulsatile ventricular assist device as a bridge to transplant for the early high-risk single-ventricle physiology

BackgroundThe use of ventricular assist devices (VADs) as a bridge-to-transplant in patients with single-ventricle physiology post–stage one palliation has been associated with poor outcomes. We describe our center's successful experience in the use of paracorporeal pulsatile VADs in the palliation of high-risk single ventricle physiology before or after the first stage of palliation with an impetus on pre-palliation implant. MethodsThis is a single-center retrospective review of univentricular patients implanted with the Berlin Heart EXCOR VAD. Our center's approach includes early implantation of the Berlin Heart EXCOR with common atrial cannulation, a cardiac index between 3.5 and 5 L/min/m2, and a bivalirudin-based anticoagulation regimen. Patient-related data were collected postimplant at week 1 and months 1, 2, and 3. Post-transplant data, including neurological outcomes, were collected. ResultsNine patients were supported. Survival to discharge post-transplant was 83% (5/6) in patients bridged-to-transplant and 33% (1/3) in patients bridged-to-decision. Six patients had no previous palliation. Median hospital stay before implantation was 111 days for nonsurvivors versus 20 days for survivors. The need for extracorporeal membrane oxygenation and cardiopulmonary resuscitation in nonsurvivors versus survivors was 1 in 3 versus 1 in 6 and 2 in 3 versus 1 in 6, respectively. There were no major central nervous system complications except for 1 significant hemorrhagic event. The pediatric overall performance category score on follow-up was normal to mild disability in 83% of survivors. Limitations include hemolysis and intermittent periods of infection and/or inflammation. ConclusionsThe use of pulsatile paracorporeal VADs is a feasible option as a bridge-to-transplant in the peri–stage one high-risk single ventricle.

Coagulation Monitoring Correlation with Bivalirudin Dosing in Pediatric Ventricular Assist Device Support

The use of bivalirudin has increased dramatically for primary thromboprophylaxis in pediatric paracorporeal ventricular assist device (VAD) support with limited data on optimal monitoring of effect. Partial thromboplastin time (aPTT) is commonly used for monitoring of bivalirudin, but can be impacted by line heparin, variability in assays and other patient factors. As such, we sought to examine the correlation of PTT to International Normalized Ratio (INR), as a possible monitoring tool for bivalirudin in in pediatric VAD patients. Retrospective single center study of all children aged <19 years, treated with bivalirudin for anticoagulation of paracorporeal VAD support. Pearson correlation coefficient was calculated for aPTT -INR and heparin absorbed (HA) aPTT-INR paired samples for each patient over the course of their support with each sample drawn at the same time. From 2015-2019, eleven patients (4 female), median age 5 months (range 0.5-40 months), weighing 7.8 kg (3.4-17.0kg) and body surface area of 0.4 m2 (range 0.2-0.7 m2) at time of implant were treated with bivalirudin for paracorporeal VAD thromboprophylaxis, of which 6 were on EXCOR devices, 4 were transitioned between continuous flow and EXCOR devices, and 1 patients was on CardioHelp extracorporeal membrane oxygenator connected to EXCOR cannula. A total of 900 days of paracorporeal VAD support generated 3,143 laboratory values for correlation. Correlations varied between aPTT assays, with highest median correlation coefficient for HA aPTT to INR of 0.72 (min 0.57 to max 0.81) in 4 patients with a total of 662 paired samples, as compared to correlation coefficient for aPTT to INR of 0.56 (min 0.32-0.91) in 10 patients with a total of 1,188 paired samples. Correlations varied between patients, with no association to age, device type or survival outcomes. The most important determinant for lack of correlation between aPTT to INR was concomitant administration of line heparin. Patients treated with bivalirudin demonstrate individual correlations of their INR to PTT, with highest correlation to HA PTT by accounting for exogenous line heparin. This preliminary data provides foundation for ongoing study into the utility of INR for bivalirudin dosing and possible future application of point of care INR testing in this population.

Utilization and Outcomes of Children Treated with Direct Thrombin Inhibitors on Paracorporeal Ventricular Assist Device Support.

Thrombotic and bleeding complications have historically been major causes of morbidity and mortality in pediatric ventricular assist device (VAD) support. Standard anticoagulation with unfractionated heparin is fraught with problems related to its heterogeneous biochemical composition and unpredictable pharmacokinetics. We sought to describe the utilization and outcomes in children with paracorporeal VAD support who are treated with direct thrombin inhibitors (DTIs) antithrombosis therapy. Retrospective multicenter review of all pediatric patients (aged <19 years) treated with a DTI (bivalirudin or argatroban) on paracorporeal VAD support, examining bleeding and thrombotic adverse events. From May 2012 to 2018, 43 children (21 females) at 10 centers in North America, median age 9.5 months (0.1-215 months) weighing 8.6 kg (2.8-150 kg), were implanted with paracorporeal VADs and treated with a DTI. Diagnoses included cardiomyopathy 40% (n = 17), congenital heart disease 37% (n = 16; single ventricle n = 5), graft vasculopathy 9% (n = 4), and other 14% (n = 6). First device implanted included Berlin Heart EXCOR 49% (n = 21), paracorporeal continuous flow device 44% (n = 19), and combination of devices in 7% (n = 3). Adverse events on DTI therapy included; major bleeding in 16% (n = 7) (2.6 events per 1,000 patient days of support on DTI), and stroke 12% (n = 5) (1.7 events per 1,000 patient days of support on DTI). Overall survival to transplantation (n = 30) or explantation (n = 8) was 88%. This is the largest multicenter experience of DTI use for anticoagulation therapy in pediatric VAD support. Outcomes are encouraging with lower major bleeding and stroke event rate than that reported in literature using other anticoagulation agents in pediatric VAD support.

Outcomes of children with congenital heart disease implanted with ventricular assist devices: An analysis of the Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs).

The reported ventricular assist device (VAD) experience in the pediatric congenital heart disease (CHD) population is limited. We sought to describe contemporary use and outcomes of VADs in children with CHD and compare these outcomes to those of non-CHD children. Patients enrolled in the Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) between September 19, 2012 through June 30, 2017 were included. CHD was classified as biventricular vs single ventricle (Stages 1, 2, or 3). Outcomes were compared between groups and multivariable analysis was used to identify factors associated with mortality on the device. Among the 471 patients enrolled, 108 (24%) had CHD (45 biventricular and 63 single ventricle). CHD patients were younger (5.7 ± 5.7 years vs 9.8 ± 6.5 years; p < 0.0001) and smaller (0.8 ± 0.5 m2 vs 1.2 ± 0.7 m2; p < 0.0001) compared with non-CHD patients. CHD patients were more likely to receive a paracorporeal continuous-flow VAD (36.1% vs 12.9%; p < 0.0001) and less likely to receive an implantable continuous-flow VAD (27.8% vs 55.0%; p < 0.0001) compared with non-CHD patients. After 6 months on a VAD, CHD patients had higher mortality (36.4% vs 12.1%) and a lower transplantation rate (29.1% vs 59.9%) than non-CHD patients (p < 0.0001). In the multivariable analysis, CHD was the factor most strongly associated with mortality on VAD (hazard ratio [HR] = 2.9; p < 0.0001), whereas the factors implantable continuous-flow device and high-volume center were protective (HR = 0.3, p < 0.0001, and HR = 0.6, respectively; p = 0.02). VAD use in children with CHD is associated with increased mortality and decreased transplant rates compared to children without CHD. For the subgroup of children with CHD who received implantable continuous-flow VADs, survival rates were higher and comparable to those of children without CHD. Increased experience correlated with better survival in pediatric VADs.