Durable VAD Research Articles

Recovery of RV Function Determines Outcomes of Extracorporeal Biventricular Support for Acute Biventricular Failure

<h3>Purpose</h3> Mechanical circulatory support for acute biventricular failure is challenging. Given that durable VAD is available only for LV support as bridge-to-transplantation in Japan, the treatment options for this pathology are limited to extracorporeal biventricular assist device (BiVAD) support first, which can be subsequently upgraded to durable LVAD in cases having recovery of RV function and transplant candidacy. The purpose of this study was to review the outcomes of extracorporeal BiVAD and to explore factors associated with the outcomes. <h3>Methods</h3> This study enrolled an institutional consecutive series of 39 cases who underwent extracorporeal BiVADs implantation for acute biventricular failure between April 2014 and October 2020. The etiological diagnosis was myocarditis in 27 cases, acute MI in 6 cases, and dilated cardiomyopathy (DCM) in 6 cases. The cases were assigned into the two groups according to the BiVAD support less than 7 days (n=18, Short group) or 7 days or more (n=21, Long group). The Long group consisted of 6 cases of acute MI (100%), 13 cases (48%) of myocarditis, two cases of DCM (33%). <h3>Results</h3> There was no case who deceased within 7 days after BiVAD implantation. In the Short group, extracorporeal LVAD was weaned-off in 11 cases (61%) or upgraded to durable LVAD in 6 cases after withdrawal of RV support within 7 days. The remaining one case deceased under extracorporeal LVAD. In the Long group, RV support was discontinued in 10 cases in the median support of 60 days (IQR; 24.2-76.8), while two cases were on BiVAD support at October 2020. The remaining nine cases (43%) deceased under BiVAD support in-hospital. Survival and VAD-free survival at 1 year were 79% and 56% in the Short group versus 48% and 20% in the Long group, respectively. <h3>Conclusion</h3> Outcomes of extracorporeal BiVAD support for acute biventricular failure were dependent on recovery of RV function. Targeting approach for RV function would be warranted for poor biventricular function.

Early Clinical Experience with Impella 5.5 at a Large Tertiary Care Center

<h3>Purpose</h3> The Impella 5.5 system is the newest temporary left ventricular assist device (LVAD) for the treatment of cardiogenic shock (CS). Impella 5.5 aims to improve deliverability and durability over Impella 5.0, but real-world experience with this device is limited. We aimed to report our clinical experience with Impella 5.5. <h3>Methods</h3> Clinical and outcome data of all patients treated with Impella 5.5 at our center between Feb and Oct 2020 were collected. AKI was defined as per KDIGO criteria, vascular complications as per VARC-2 criteria and severe thrombocytopenia as <50k. <h3>Results</h3> 13 patients with Impella 5.5 were managed at our center (9 (69%) male, median age 58y (IQR 52, 67). 5 patients were transitioned to Impella 5.5 from VA-ECMO, 2 from Impella CP, 2 from IABP, and 4 from inotropes. Etiology of CS was AMI in 6 cases, decompensated chronic HF in 5, suspected acute myocarditis in 1 and post-cardiotomy CS in 1 case. Median duration of Impella 5.5 support was 12 days (IQR 7-28). 2 patients required device removal due to complications: 1 with entanglement in the mitral subvalvular apparatus, 1 with migration into the ascending aorta. Device-related complications were hemolysis in 4 (30%) patients, severe thrombocytopenia in 1, axillary hematoma (minor as per VARC-2 criteria) in 3 (23%), and AKI in 2 patients (15%). No stroke, valve injury or limb complications occurred. Survival to device explant was 85%. 2 patients who were not candidates for durable LVAD or transplant died on support of refractory CS. Of the survivors, 2 required surgically implanted biventricular support for refractory ventricular arrhythmia, 4 were bridged to durable VAD, 2 were bridged to OHT, and 3 achieved ventricular recovery. At the time of analysis, 3 patients remain hospitalized (1 surgical BIVAD, 1 early post-durable LVAD, 1 recovered after device explant). <h3>Conclusion</h3> All patients supported with Impella 5.5 were critically ill in profound CS. Rates of procedural and device-related complications were favorable, and survival was high in this critically ill cohort.

Resource utilization in children with paracorporeal continuous-flow ventricular assist devices

Paracorporeal continuous-flow ventricular assist devices (PCF VAD) are increasingly used in pediatrics, yet PCF VAD resource utilization has not been reported to date. Pediatric Interagency Registry for Mechanically Assisted Circulatory Support (PediMACS), a national registry of VADs in children, and Pediatric Health Information System (PHIS), an administrative database of children's hospitals, were merged to assess VAD implants from 19 centers between 2012 and 2016. Resource utilization, including hospital and intensive care unit length of stay (LOS), and costs are analyzed for PCF VAD, durable VAD (DVAD), and combined PCF-DVAD support. Of 177 children (20% PCF VAD, 14% PCF-DVAD, 66% DVAD), those with PCF VAD or PCF-DVAD are younger (median age 4 [IQR 0-10] years and 3 [IQR 0-9] years, respectively) and more often have congenital heart disease (44%; 28%, respectively) compared to DVAD (11 [IQR 3-17] years; 14% CHD); p < 0.01 for both. Median post-VAD LOS is prolonged ranging from 43 (IQR 15-82) days in PCF VAD to 72 (IQR 55-107) days in PCF-DVAD, with significant hospitalization costs (PCF VAD $450,000 [IQR $210,000-$780,000]; PCF-DVAD $770,000 [IQR $510,000-$1,000,000]). After adjusting for patient-level factors, greater post-VAD hospital costs are associated with LOS, ECMO pre-VAD, greater chronic complex conditions, and major adverse events (p < 0.05 for all). VAD strategy and underlying cardiac disease are not associated with LOS or overall costs, although PCF VAD is associated with higher daily-level costs driven by increased pharmacy, laboratory, imaging, and clinical services costs. Pediatric PCF VAD resource utilization is staggeringly high with costs primarily driven by pre-implantation patient illness, hospital LOS, and clinical care costs.

Less Invasive Approach to Left Ventricular Assist Device Implantation May Improve Survival in High-Risk Patients

Despite improvement in outcomes after left ventricular assist device (LVAD) implantation over the past 2 decades, high-risk recipients continue to have a prohibitive rate of morbidity and mortality. We hypothesized that a less invasive approach to LVAD implantation would be associated with improved survival compared to a conventional approach in this high-risk cohort. All consecutive LVAD recipients (2013 to 2017) that underwent centrifugal LVAD implantation were retrospectively reviewed. Patients were classified as high-risk if INTERMACS 1 or required temporary VAD/venoarterial extracorporeal membrane oxygenation prior to durable VAD implantation. Patients were stratified into 3 groups: left thoracotomy with hemi-sternotomy (LTHS) high-risk, conventional sternotomy (CS) high-risk, and non-high-risk. The primary outcome was 1-year survival. A total of 57 patients (LTHS high-risk: 11, CS high-risk: 12, non-high-risk: 34) were identified. Preoperative right ventricular failure scores, HeartMate-II mortality scores, and end-organ dysfunction were similar between the 2 high-risk groups. While operative time was similar between the 3 groups, cardiopulmonary bypass time was significantly shorter in the LTHS high-risk group compared to other groups. There was a trend toward decreased intensive care unit length of stay and ventilator time in LTHS high-risk compared to CS high-risk patients. Moreover, between these 2 groups, there was a significant decrease in temporary right VAD support (50% vs 0%, P = 0.014), and 1-year survival was significantly higher in the LTHS group (42% vs 91%, P = 0.025). Less invasive LVAD implantation appears to be associated with improved survival compared to conventional LVAD implantation in high-risk patients.

Outcomes of Heart Transplantation Bridging Strategies: Durable VAD vs IABP vs Medical Therapy

Heart transplantation candidates are often bridged to transplantation with medical therapy (MT) or mechanical circulatory support (MCS). Recent changes were made in the UNOS adult heart allocation system, partly based on bridging strategy, and potential effects remain uncertain. We compared outcomes of patients bridged to OHT with durable VAD (dVAD), intra-aortic balloon pump (IABP), and MT prior to the new allocation system. A retrospective review was performed on 513 consecutive patients listed for OHT between April 2004 and December 2018. Patients were excluded if bridged with extracorporeal ventricular assist devices or multiple concomitant MCS devices. Pre-, intra-, and post-operative characteristics were compared between the BTT strategies. Continuous variables are expressed as mean ± standard deviation or median (Q1-Q3) while categorical variables are expressed as number (%). A total of 501 patients were included (age 54.5(42.5-62.0) years, 104(30%) female). Of these, 348(69.5%) were transplanted (dVAD 175(50.3%), IABP 69(19.8%), and 104(29.9%) MT). Overall, 30-day mortality was 4% and 2-year mortality was 11%. dVAD had longer CPB minutes (dVAD 155.9±42.9, IABP 145.3±65.7, MT 139.7±52.6, p=0.031), but donor ischemic minutes were similar (dVAD 179.9±44.4, IABP 188.2±49.1, MT 179.9±53.7, p=0.44). IABP patients had longer overall LOS (IABP 55.0(31.0-90.0) days, dVAD 16.0(11.0-26.0) days, MT 40.0(20.5-75.0) days, p<0.001), but post-transplantation LOS was similar. Survival rates at 1, 2, 5, and 10 years were similar across groups (p=0.18, Figure). There were 28 deaths on the waiting-list, 13 dVAD, 2 IABP, and 13 MT. In this study, OHT outcomes were similar between the three bridging strategies, but overall LOS was higher in the IABP group. Further study is needed to determine the long-term effects of the new UNOS allocation system in regards to waiting-time, death on waiting list, transplant survival and cost-effectiveness of these bridging strategies.

How Does Double Tunnel Driveline Derivation Technique Contributes to Treatment of Driveline Infection?

Driveline infection (DLI) is one of the major complications after durable VAD implantation. Since 2016, we have changed from the standard method to a double-tunnel method for driveline (DL) derivation, in which DL was once led to the upper right abdomen, then passed through the subcutaneous tissue horizontally to the left upper abdomen. This study aimed to verify the therapeutic efficacy of the double tunnel method on DLI. From April 2013 to January 2019, all 120 cases of HeartMate2(HM2) implanted for BTT at our hospital were divided into 2 groups; 38 cases for whom DL exited directly from the upper right abdomen (S group) or 82 cases of the double tunnel method (D group). There was no significant intergroup difference in age (41 vs 46; P = 0.05), male ratio 79% vs 67%, (p = 0.2), or BTB case (16% vs 31%, P = 0.1). DLI occurred in 12 cases (32%) in the S group and 14 cases (17%) in the D group (P = 0.1). The interval between the HM2 implantation and the first DLI occurrence was not significantly different (585 vs 414 days, P = 0.2). Treatment of the DLI was more conservative in the S group, where surgical DL translocation (DTL) was performed in 1 case (8%) in the S group and 10 cases (71%) in the D group (P &lt;0.01). The DTL resulted in primary cure 1 case of the S group (100%) and 8 cases of the D group (80%). The 2 cases who failed to show primary cure post-DTL underwent pump exchange. The medical therapy and/or local irrigation was selected as the primary treatment of DLI in 8 cases of the S group (67%) and in 4 cases of the D group (29%) As a result, 1 case of the S group and 1 case of the D group showed the primary cure, whereas the remaining 10 cases (83%) continued daily wound care and intravenous antibiotics in hospital. DLI occurred one year or more after durable VAD implantation on average, regardless of the driveline derivation method. The double tunnel method contributed to opening the window for aggressive surgical treatment which more frequently resulted in a primary cure of the DLI than the conservative therapy.

Indications and Outcomes for Temporary Mechanical Circulatory Support in Pediatric Patients with Cardiac Failure.

Temporary continuous-flow ventricular assist devices (cfVAD) and extracorporeal membrane oxygenation (ECMO) are options for temporary mechanical circulatory support in pediatric patients. Despite the increase in temporary cfVAD use, the literature describing its use in pediatrics is limited. This was a single-center retrospective review of temporary cfVAD and a cohort of similar ECMO patients between January 1, 2011, and June 30, 2016, in patients <19 years of age. Thirteen patients underwent temporary cfVAD placement and 11 patients underwent ECMO cannulation for similar indications during the study period. Precannulation data were not statistically different, except for higher lactate and lower pH in the ECMO cohort. Median length of cfVAD support was 20 days (range 6-227), compared with 9 days (range 1-15) on ECMO. Primary outcome for cfVAD patients was one decannulated with recovery, six transplanted, and six died, compared with ECMO patients with five decannulated with recovery, three transplanted after conversion to durable VAD, and three died. No patients were transplanted directly from ECMO. This review provides new evidence that temporary cfVAD use can be used to support pediatric patients more than longer periods of time compared with ECMO, with transition to durable VAD and transplant.

Patients with Surgical Corrected TGA or Congenital Corrected TGA Supported with Durable VAD

Purpose We aimed to analyze durable VAD support of an anatomical right ventricle as systemic ventricle (any patients born with a transposition of the great arteries (TGA); either ccTGA or surgical corrected TGA using Mustard/Senning procedure). Methods Data retrieval from the EUROMACS registry (13th December 2017) with 3129 durable VAD implantations listed 68 patients with CHD. Sixteen patients (3♀,13♂), from 8 different centres, were identified to suffer from TGA (2 ccTGA, 14 dTGA). Results The study group had a median age of 33yrs. (range 2 - 74) compared to a median age of 51.6 yrs. (range 1 - 81) to the rest of the registry. The mean ejection fraction of the systemic ventricle was 20% ±3.6% at time of implantation. Most patients were in Intermacs stage 2 (range 1-4), two patients were on ECMO, one on IABP and 12 on inotropes prior to implantation. Two patients received a BiVAD (both dTGA)(Berlin Heart (1), HM II (1) whereas all others received a SVAD/LVAD (HM II (5), HVAD (9)). Intention to treat was transplantation (12), permanent support (2) and bridge to decision (2). Mean overall follow-up time was 513.5 ±366 days (range 20-1169). Seven patients were transplanted after a mean support time of 386 ±226.7 days. Three patients are still on support. Overall 38% of patients died (n:6) on support (median support time: 501 ±325 days). One year mortality was 12.5% (n:2). Conclusion Compared with the second annual EUROMACS report (2,681 pts.) where one year survival was reported with 66%, we found in this small cohort (16 pts.; 0.5% of the whole database) a one year survival of 87.5%. Of note is the significant younger age at implantation for this cohort compared to the rest of the EUROMACS registry Population.

Approaches to Repairing Outflow Graft Stenosis in Left Ventricular Assist Devices

Purpose Durable Left Ventricular Assist Devices (LVAD) are typically implanted with an inflow cannula in the LV apex and an outflow graft anastomosed to the aorta. We describe 4 pts who experienced clinically significant outflow graft stenosis requiring intervention, an underreported but likely increasingly common complication in pts on long term support with a VAD. Methods A retrospective review of our VAD database was performed on pts implanted with a durable VAD at our institution from 2011-2018. Results Four pts were found to have stenosis of the outflow graft confirmed by CT angiogram (Figure). Each of the pts presented with symptoms of acute on chronic LV failure with a decrease in VAD flows, prompting the diagnostic evaluation. The pre-VAD etiology of heart failure was nonischemic cardiomyopathy for 3 pts and transposition of the great arteries with VAD implanted into the systemic ventricle in the 4thpatient. Mean time from implant to diagnosing the stenosis was 722 days. In all pts the cause of the stenosis was external compression from accumulation of fluid or hematoma between the gore-tex applied at the time of implant and the outflow graft. The stenosis was focal in three and diffuse in one pt. Two of the pts were successfully treated with stenting of the outflow graft and one pt was taken for surgical release of the gore-tex. In the 4thpt, the stenosis was an incidental finding as we diagnosed acute thrombus ingestion into the inflow cannula which resolved with thrombolytics. All pts experienced an immediate increase in >2L of VAD flow following each, respective, intervention. Conclusion Outflow graft stenosis in VADs is a serious complication that can lead to decompensated heart failure, the cause of which may be external compression related to gore-tex around the graft. This complication should be included in the differential diagnosis of a drop in VAD flows, and while treatable, should prompt a reassessment of how gore-tex is applied (if at all) at the time of implant.

Role of ECMO as Bridge to VAD Therapy in Critically Ill Pediatric Patients - An Analysis of the STS Pedimacs Database

Purpose Extra-corporeal membrane oxygenation (ECMO) as bridge to ventricular assist device (EB-VAD) therapy is frequently used for initial resuscitation of critically ill pediatric patients (INTERMACS 1 & 2). Data regarding outcomes with this strategy is limited. Methods INTERMACS 1 & 2 patients enrolled in Pediatric Interagency Registry for Mechanical Circulatory Support (PEDIMACS) between September 19th, 2012 & December 31st, 2017 constituted the study group. Of 370 patients, 271 received primary VAD (P-VAD) implantation & EB-VAD was utilized in 99 patients. Patient characteristics, durable VAD outcomes & time to first adverse event with & without preoperative ECMO bridge were compared. Sub-analysis of INTERMACS 1 patients was conducted. Results Lower age (p=0.0001) & critical cardiogenic shock(p tube feeding , mechanical ventilation & paralytics (p Conclusion In INTERMACS 1 & 2 patients EB-VAD strategy is associated with poor early & late post-implant survival. Within INTERMACS 1 early survival is comparable with both strategies. EB-VAD could potentially benefit high risk INTERMACS 1 patients

Allosensitization does not alter post-transplant outcomes in pediatric patients bridged to transplant with a ventricular assist device.

Patients supported with a VAD are at increased risk for sensitization. We aimed to determine risk factors for sensitization as well as the impact of sensitization on post-transplant outcomes. The UNOS database (January 2004-June 2014) was used to identify patients (≤18yrs) supported with a durable VAD. Rates and degree of sensitization in the VAD cohort were calculated. Post-transplant survival was determined comparing outcomes of sensitized vs. non-sensitized patients. There were 3097 patients included in the study; 19% (n=579) were bridged with a VAD. Of these, 41.8% were sensitized vs. 29.9% of the patients who were not bridged with a VAD (p<0.001). VAD was an independent predictor of sensitization (OR 2.05 [1.63-2.57]; p<0.001). There was no difference in sensitization based on device type (continuous vs. pulsatile flow, p=0.990). Post-transplant survival rates between the sensitized and non-sensitized VAD patients were not different, including patients with a PRA >50% and VAD patients with a positive DSC (p=0.280 and 0.160, respectively). In conclusion, pediatric VAD patients are more likely to be sensitized, but there was no difference in sensitization based on device type. In addition, sensitization does not appear to impact outcomes.

(941) - Integration of Palliative Care in End of Life Care for Patients on Durable Mechanical Circulatory Support

Although outcomes for patients on durable ventricular assist device therapy (VAD) continue to improve, patients are still plagued with frequent hospitalizations and limited long-term survival. Little data exists on the optimal timing of and setting for palliative care involvement for these patients. We conducted a retrospective chart review of our single center’s experience to understand how and where VAD patients die. Charts for all patients who died after receiving a durable VAD between August 2008 and January 2015 were reviewed. Only patients who survived index hospitalization and subsequently died on VAD support were included for analysis. Data on demographic, VAD implant data, medical complications, and palliative care utilization were abstracted retrospectively. A total of 62 patients died following VAD implant for either bridge to transplantation (BTT) (49 (79%)) or destination therapy (DT) (13(21%)). Of those, 37 (60%) patients died during the index hospitalization and 25 (40%) patients survived the index hospitalization but ultimately died on VAD support (BTT 66%, DT 34%). Their mean age at time of implant was 59.0 (SD 11.6) years and 84% were male. These patients lived an average of 15.6 (SD 12.4) months on VAD support. Inpatient palliative care team consultation occurred for 12 (48%) of patients at an average of 23.6 (SD 65.3) days prior to death. Causes of death were identified as intracranial bleeding (8 (32%)); pump complications (5 (20%)); sepsis (4 (16%)); multi-organ system failure (3 (12%)), respiratory failure (2 (8%)) and unknown (3 (12%)). Deaths were thought to be sudden, or unexpected, in 14 (56%) patients. Sixteen (64%) patients died in the hospital, 5 (20%) died at home and 4 (16%) died in inpatient hospice. The majority of VAD patients die in hospital settings, but many die at home, and die suddenly. Although palliative care consultation occurred in nearly half of these patients with durable VAD, palliative care was consulted months after VAD implant and near the end of life. There is ongoing need for earlier involvement of palliative care for this population, particularly in the outpatient setting, as a way to improve advanced care planning, symptom management, alignment of treatment preferences with treatments received, as well as caregiver bereavement.

Abstract 11760: The Outcomes of Children Implanted With Ventricular Assist Devices in the US: First Analysis of the Pediatric Interagency Registry for Mechanical Circulatory Support (PediMACS)

BACKGROUND: Use of pediatric mechanical circulatory support to decrease mortality has expanded dramatically. A national account of the use of FDA-approved devices in children is essential to understanding outcomes, refining patient selection, and improving quality of care. METHODS: PediMACs is an NIH-supported national registry for FDA-approved temporary and durable VAD usage in patients &lt; 18 years of age. Between the launch in Sept 2012 and March 2014, 32 US hospitals enrolled patients. This first report of data from this registry analyzed pre-implant patient characteristics, survival using competing outcomes, and adverse events. RESULTS: One hundred and thirty pediatric pts underwent 153 VAD implantations. Etiology of heart disease included 87 (67%) pts with cardiomyopathy, 26 (20%) with congenital heart disease. Twenty pts transitioned from ECMO and 37 had prior cardiac surgery. Most pts were Intermacs level 1 (28%) and level 2 (55%) at implant, with 12% Intermacs level 3. There were 26 temporary devices. Of the durable devices, 65 (51%) were pulsatile and 62 (49%) continuous flow (CF) (compared to adult Intermacs implants: 4% pulsatile, 96% CF). Age at first implant included 22 pts (17%) &lt; 1 yr of age, 23 (18%) 1-5 yrs, 26 (20%) 6-10 yrs and 59 (45%) 10-18 yrs. Patients were supported with LVAD alone in 99 (76%), BiVAD in 24 (18%) and total artificial heart in 2 (2%) and represented 484 months of follow-up. The 104 patients receiving primary durable devices had an actuarial survival of 90% at 6 mos. Competing risk analysis at 6 mos revealed 54% of pts transplanted, 37% alive on support, 8 % died and 1 % recovery. In the overall cohort, there were 8 early (&lt;1mo) and 5 late deaths. Reported serious adverse events included infection (42), bleeding (40), device malfunction (37) and neurologic dysfunction (33). CONCLUSIONS: Pedimacs constitutes the largest single data repository with detailed information of pediatric pts implanted with all types of VADs. Initial data show a higher rate of use of pulsatile devices as compared to contemporaneous adult data. Survival rates are excellent despite varying patient characteristics and pump types. With further data collection, analysis of patient risk factors critical to improving outcomes will be possible.

648 Midterm Outcomes of Patients Undergoing Durable VAD Support for Acute Myocardial Infarction Complicated with Cardiogenic Shock

648 Midterm Outcomes of Patients Undergoing Durable VAD Support for Acute Myocardial Infarction Complicated with Cardiogenic Shock