Pulsatile Ventricular Assist Device Research Articles

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.

Outcomes of Children Supported With Pulsatile Paracorporeal Ventricular Assist Device: Congenital Versus Acquired Heart Disease.

We reviewed the outcomes of 82 consecutive pediatric patients (less than 18 years of age) supported with the Berlin Heart ventricular assist device (VAD), comparing those with congenital heart disease (CHD; n  =  44) with those with acquired heart disease (AHD; n  =  37). The primary outcome was mortality after VAD insertion. Kaplan-Meier methods and log-rank tests were used to assess group differences in long-term survival. Forty-four CHD patients were supported (age: median  =  65 days, range  =  4 days-13.3 years; weight [kg]: median  =  4, range  =  2.4-42.3). Ten biventricular CHD patients were supported with eight biventricular assist devices (BiVADs), one left ventricular assist device (LVAD) only, and one LVAD converted to BiVAD, while 34 univentricular CHD patients were supported with single ventricle-ventricular assist devices (sVADs). In CHD patients, duration of VAD support was [days]: median  =  134, range  =  4-554. Of 44 CHD patients, 28 underwent heart transplantation, 15 died on VAD, and one was still on VAD. Thirty-seven AHD patients were supported (age: median  =  1.9 years, range  =  27 days-17.7 years; weight [kg]: median  =  11, range  =  3.1-112), including 34 BiVAD and 3 LVAD. In AHD patients, duration of VAD support was [days]: median  =  97, range  =  4-315. Of 37 AHD patients, 28 underwent transplantation, three died on VAD, five weaned off VAD (one of whom underwent heart transplantation 334 days after weaning), and one was still on VAD. One-year survival after VAD insertion was 59.9% (95% CI  =  46.7%-76.7%) in CHD and 88.6% (95% CI  =  78.8%-99.8%) in AHD, P  =  .0004. Five-year survival after VAD insertion was 55.4% (95% CI  =  40.8%-75.2%) in CHD and 85.3% (95% CI  =  74.0%-98.2%) in AHD, P  =  .002. Pulsatile VAD facilitates bridge-to-transplantation in neonates, infants, and children with CHD; however, survival after VAD insertion is worse in patients with CHD than in patients with AHD.

CARD25: Development of a Minimally Invasive Single Port Pulsatile Ventricular Assist Device

Purpose: Our goal is to develop a compact, single port, pulsatile ventricular assist device (VAD) for total left ventricle (LV) support that only requires a minimally invasive single cannulation from apex to aorta. Methods: Standard diaphragm displacement pumps have 2 valved ports and inlet/outlet cannulas to alternate between blood infusion and withdrawal. By contrast, our compact single port pulsatile VAD consists of a valved single lumen cannula and a valveless single port diaphragm displacement pump. Via a small left thoracotomy, the valved single lumen cannula is inserted from apex to aorta (Fig). Four one-way inlet valves on the valved single lumen cannula wall allow blood withdrawal from LV, and a tri-leaflet outlet valve at the cannula tip allows blood delivery to aorta. The 28 Fr valved single lumen cannula prototype was made as one piece by polyurethane (PU) dip molding with memory alloy reinforcement. The two halves of the valveless single port diaphragm displacement pump prototype housing were made by polycarbonate vacuum thermoforming and assembled with a flexible PU membrane diaphragm in the middle to separate the blood and pneumatic chambers. This pump had a 60 cc stroke volume. A closed mock loop with 37% glycerin was used to mimic the LV-aortic valve-ascending aorta tract. Priming volume and reservoir height were adjusted to maintain 70 mm Hg diastolic aortic pressure and 16 mm Hg preload. Circuit flow and pressure in valved single lumen cannula were recorded. The catheter introducer with pressure transducer on tip was inserted through apex in adult sheep (n=5, 44-52 kg), with pressure wave form guiding tip into ascending aorta. The valved single lumen cannula slid along introducer through apex, crossing aortic valve, with its tip in ascending aorta. The valved single lumen cannula was connected to the single port diaphragm displacement pump. Pumping was increased for a normal cardiac output. The single port pulsatile VAD prototype performance was assessed for 6 hrs with hemodynamics/blood counts recorded. Results: The valved single lumen cannula and single port diaphragm displacement pump prototypes were fabricated as designed. The bench study showed that the single port pulsatile VAD achieved a pumping flow of up to 3.75 L/min. Valve regurgitation was <3%. In the sheep study, the valved single lumen cannula was easily installed within 1 min at first attempt. The single port pulsatile VAD achieved maximal 3.75 L/min pumping flow in a 52 kg sheep. The single port pulsatile VAD had consistent pumping flow through 6 hrs with stable hemodynamics (Table). Hemoglobin and platelet/white blood cell counts were unchanged. No obvious injury or thrombosis in heart or single port pulsatile VAD were observed at necropsy. Conclusions: Our single port pulsatile VAD only requires a single apex cannulation with valved single lumen cannula to achieve reliable LVAD performance, showing great promise for a short to mid-term minimally invasive LVAD.Figure 1. Our single port pulsatile ventricular assist device with a valved single lumen cannula and a valveless single port diaphragm displacement pump. Table 1. - Hemodynamics and Blood Count Results Sheep 1-5 Baseline Pump Run1 hr Pump Run3 hr Pump Run6 hr sABP (mm Hg) 111±15.5 138±19.5 122±16.4 113±16.2 CVP (mm Hg) 11±0.4 11±0.8 11±0.5 11±0.8 CO (L/min) 2.5±0.38 3.8±0.98 3.6±0.66 3.5±0.66 Pump Flow (L/min) 0±0 2.8±0.65* 2.7±0.65* 2.7±0.52* HR (bpm) 154±61.1 104±44.7 105±39.3 127±16 WBC (103/uL) 4.1±0.14 N/A N/A 4.8±2.57 PLT (103/uL) 467±93.3 N/A N/A 380±171 HgB (g/dL) 9.4±0.45 N/A N/A 9.1±0.38 * p<0.05 vs Baseline sABP=systolic arterial pressure, CVP=central venous pressure, CO=cardiac output, HR=heart rate, WBC=white blood cell count, PLT=platelet count, HgB=hemoglobin, and N/A=not applicable.

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.

P75: In Vivo Evaluation of a Paracorporeal Pulsatile Ventricular Assist Device in an Ovine Model

Background: Ventricular assist devices (VAD) have undergone numerous changes and improvements since their conception. One of the most notable advances was the paradigm change from pulsatile to non-pulsatile, continuous-flow (CF) rotary pumps, which are smaller and more durable. Despite these improvements, the price of CF-VADs makes them challenging to access in developing countries. Hence, an easily implantable, cost-effective VAD has the potential to increase access to life-saving procedures around the world. In this study, we performed two 30-day experiments to assess the safety and durability of the final version of the Vitalmex Paracorporeal Pulsatile Ventricular Assist Device (PPVAD). Methods: The device was implanted in two healthy sheep for 31 and 32 days. Implantation was performed by inserting the inflow cannula into the left ventricular apex and suturing the outflow graft to the descending aorta. Hemodynamic data, such as VAD pulse rate, flow, and pressures, were recorded. Bloodwork, including chemistry, hematology/coagulation profile, and plasma-free hemoglobin, was taken. A necropsy was performed at the end of the study. Values are reported as means with standard deviations. Results: Both animals reached the intended endpoint without any unexpected device-related problems. A fixed VAD rate of 65 bpm was maintained throughout most of the study duration. The average VAD flow was 3.14 ± 0.9 L/min. Plasma-free hemoglobin values were 10.15 ± 3.95 mg/dL. The histopathologic evaluation reported interstitial nephritis and mild cortical fibrosis of the adrenal glands. Thromboembolic incidents were observed in the liver and lungs; these were not clinically significant. The tissue changes surrounding the implant site at the left ventricle and descending aorta were within the expected degree of inflammation and fibrosis. Conclusion: The PPVAD can provide safe pulsatile mechanical circulatory support for 30 days. This device can offer an easily implantable, cost-effective alternative to currently available VADs.

(610) A Single Institutional Experience with 36 Children Smaller Than 5 Kilograms Supported with Pulsatile Ventricular Assist Device

(610) A Single Institutional Experience with 36 Children Smaller Than 5 Kilograms Supported with Pulsatile 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.

A Physiological Control System for Pulsatile Ventricular Assist Device Using an Energy-Efficient Deep Reinforcement Learning Method

Pulsatile ventricular assist device (PVAD) is a blood pump used to assist the circulation support of the native heart. Because of patients’ complex physiological environment, PVAD’s control system requires high adaptive ability and low computational energy. However, traditional PID controllers do not possess sufficient adaptive ability. Although neural network controllers are with high adaptive ability, their extensive energy cost limits the applications. In this study, a PVAD physiological control system based on deep reinforcement leaming (DHL) is proposed, which significantly improves the system’s adaptive ability. To fiirther reduce its energy cost, a new energy-efficient DRL method, AddTD3, is developed, in which the fully connected network (FC) with high computation complexity is replaced by energy-efficient AdderNet. Experimental results show that the proposed AddTD3 controller is with higher adaptive ability than the traditional PID controller (cumulative absolute error: 237.1 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mmHg</i> vs. 484.3 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mmHg</i> ) and can be migrated to the mock circulation system without fine-tuning. It can reduce the energy cost of traditional DRL algorithm TD3 to 44.8% without reducing the performance (8773.2 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">pj</i> vs. 22420.4 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">pj</i> ).

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.

Ventricular Assist Device Use in Patients With Single-Ventricle Circulation.

Ventricular assist devices (VADs) are being increasingly used to support patients with congenital heart disease and single-ventricle physiology. Because of their unique anatomy and physiology, special consideration must be used to provide effective mechanical circulatory support for each individual patient. This can include alternative cannulation techniques, strategies to balance cardiac output to the systemic and pulmonary circulations from a single ventricle, or the use of continuous vs pulsatile VADs for better ventricular offloading. In this article we review the etiology of single-ventricle failure, VAD options for support, cannulation strategies, post-VAD management considerations, and outcomes at each of the 3 stages of palliation.

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.

P89: Stage II Single Ventricle Patients Can Be Successfully Bridged to Transplant with a Pulsatile Ventricular Assist Device and Bidirectional Glenn Anastomosis

P89: Stage II Single Ventricle Patients Can Be Successfully Bridged to Transplant with a Pulsatile Ventricular Assist Device and Bidirectional Glenn Anastomosis

Analysis of 82 Children Supported With Pulsatile Paracorporeal Ventricular Assist Device: Comparison of Patients With Biventricular Versus Univentricular Circulation

We reviewed outcomes in 82 consecutive children supported with the Berlin Heart pulsatile ventricular assist device (VAD), comparing those with functionally univentricular circulation (n = 34) to those with biventricular circulation (n = 48). The primary outcome was mortality. Kaplan-Meier (KM) methods and log-rank tests were used to assess group differences in long-term survival. T-tests using KM-estimated survival proportions and standard errors were used to compare groups at specific time points. 48 biventricular patients were supported (Age: median = 1.4 years, range = 17 days-17.7 years; Weight [kilograms]: median = 9.4, range = 3.1-112), including 43 BiVAD, 4 LVAD only, and 1 LVAD converted to BiVAD. In biventricular patients, duration of VAD support [days]: median = 97, range = 4-315. Of 48 biventricular patients, 35 underwent heart transplantation, 7 died on VAD, 5 weaned off VAD (1 of whom underwent heart transplantation 334 days after weaning), and 1 is still on VAD. 34 univentricular patients were supported with single VAD (sVAD) (Age: median = 38.5 days, range = 4 days-13.3 years; Weight [kilograms]: median = 3.98, range = 2.4-32.6). In univentricular patients, duration of VAD support [days]: median = 138, range = 4-554. Of 34 univentricular patients, 22 underwent transplantation, 11 died on VAD, and 1 is still on VAD. One-year survival after VAD insertion was 82.7% (95% CI = 72.4-94.4%) in biventricular patients and 59.7% (95% CI = 44.9-79.5%) in univentricular patients, p = 0.026. Five-year survival after VAD insertion was 79.7% (95% CI = 68.6-92.6%) in biventricular patients and 50.5% (95% CI = 35.0-73.0%) in univentricular patients, p = 0.010. Pulsatile VAD facilitates bridge to transplantation in neonates, infants, and children with functionally univentricular circulation; however, survival is worse than in patients with biventricular circulation.

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.

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.

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.

Palliation Plus Ventricular Assist Device Insertion in 15 Neonates and Infants With Functionally Univentricular Circulation

BackgroundWe report 15 high-risk neonates and infants with functionally univentricular circulation stabilized with initial surgical palliation plus ventricular assist device (VAD) insertion (PALLIATION+VAD) in preparation for transplantation. MethodsFifteen functionally univentricular patients with ductal-dependent systemic circulation (8 hypoplastic left heart syndrome, 1 hypoplastic left heart syndrome-related malformation: 7 neonates, 2 infants) or ductal-dependent pulmonary circulation (6 hypoplastic right heart syndrome: 5 neonates, 1 infant) presented with anatomical and/or physiological features associated with increased risk for conventional univentricular palliation (large coronary sinusoids with ventricular-dependent coronary circulation, severe systemic atrioventricular valvar regurgitation, cardiogenic shock, or restrictive atrial septum). PALLIATION+VAD for patients with ductal-dependent systemic circulation was: VAD insertion plus application of bilateral pulmonary bands, stent placement in the arterial duct, and atrial septectomy, if needed. PALLIATION+VAD for patients with ductal-dependent pulmonary circulation was: VAD insertion plus stent placement in the arterial duct or systemic-to-pulmonary artery shunt with pulmonary arterioplasty, if needed. ResultsAt PALLIATION+VAD, median age was 20 days (range, 4-143 days) and median weight was 3.47 kg (range, 2.43-4.86 kg). Ten patients (67%) survived and 5 patients (33%) died. All ten survivors are at home doing well after successful transplantation. Only 2 of 10 survivors (20%) required intubation >10 days after PALLIATION+VAD. Median length of VAD support for all 15 patients was 138 days (range, 56-226 days). ConclusionsHigh-risk neonates with functionally univentricular hearts who are suboptimal candidates for conventional palliation can be successfully stabilized with pulsatile VAD insertion along with initial palliation while awaiting cardiac transplantation; these patients may be extubated, enterally nourished, and optimized for transplantation while on VAD.

Extreme membrane position detection and pump output estimation in pulsatile VADs

One of the disadvantages of pulsatile ventricular assist devices (VADs) is the lack of feedback information about the flow and the range of diaphragm movement. This influences the proper selection of control parameters and control automation. Objective: The aim of the present study was to develop algorithms for complete emptying (CE) and complete filling (CF) detection as well as stroke volume estimation. Methods: The developed methods do not require additional measurements, as they are based on the data from the VAD control unit and the modeled value of the flow in the VAD blood chamber Siewnicka and Janiszowski (2018) [1]. The experiments were performed on a measurement stand of a hybrid simulator of the cardiovascular system with a connected POLVAD-MEV device. The algorithms were developed and then tested for a wide range of device operation conditions. Results: The CF detection algorithm had one missed detection out of 39 measurements. The CE algorithm was free of errors for all investigated cases. The pump output algorithm was approximately 90% accurate in relation to the direct measurement. Conclusion and significance: The application of these methods to pulsatile VADs may be very convenient for the medical operators of these devices and could result in a considerable improvement in the field of treatment safety. An abstract of this work was reported in Siewnicka et al., 2017 [2].

Combined Hybrid Procedure and VAD Insertion in 9 High-Risk Neonates and Infants With HLHS

BackgroundThis report describes 9 high-risk neonates and infants with hypoplastic left heart syndrome (HLHS) who were stabilized with a combined hybrid approach and ventricular assist device (VAD) insertion (HYBRID+VAD) in preparation for heart transplantation. MethodsA total of 9 patients with HLHS (7 neonates, 2 infants) presented with anatomic or physiologic features associated with an increased risk for conventional univentricular palliation with the Norwood operation (large coronary sinusoids or fistulas, severe tricuspid regurgitation, cardiogenic shock, restrictive atrial septum). These patients underwent combined VAD insertion (Berlin EXCOR, Berlin Heart, Inc, Berlin, Germany) and Stage 1 hybrid palliation (application of bilateral pulmonary bands, stent placement in the patent arterial duct, and atrial septectomy if needed). During this same era, at the Congenital Heart Center, University of Florida, Gainesville, Florida, 46 neonates underwent a Norwood operation, 4 neonates underwent a hybrid approach “Stage 1” without VAD, and 3 patients with HLHS were supported with prostaglandin while awaiting heart transplantation. ResultsAt HYBRID+VAD insertion, the median age was 20 days (range, 13 to 143 days), and median weight was 3.25 kg (range, 2.43 to 4.2 kg). Six patients survive (67%), and 3 patients died (33%). Five survivors are at home doing well after successful heart transplantation, and 1 survivor is doing well in the intensive care unit on VAD support while awaiting transplantation. Only 1 of 6 survivors (16.7%) required intubation more than 10 days after HYBRID+VAD insertion. In 8 patients no longer undergoing VAD support, the median length of VAD support was 119.5 days (range, 56 to 196 days). ConclusionsHigh-risk patients with HLHS who are suboptimal candidates for Norwood palliation can be successfully stabilized with pulsatile VAD insertion along with hybrid palliation while awaiting cardiac transplantation. These patients may be extubated and optimized for transplantation while undergoing VAD support.