Can we safely expand the donation after circulatory death donor heart pool by extending the donor age limit?

OBJECTIVE: This study evaluates the impact of donor age on outcomes following donation after circulatory death heart transplantation. METHODS: The United Network for Organ Sharing registry was queried to analyze adult recipients who underwent isolated donation after circulatory heart transplantation from January 1, 2019, to September 30, 2023. The cohort was stratified into 2 groups according to donor age, where advanced donor age was defined as 40 years or more. Outcomes were 90-day and 1-year post-transplant survival. Propensity score matching was performed. Subgroup analysis was performed to evaluate the effects of recipient age on 90-day survival among the recipients with advanced-age donors. RESULTS: A total of 994 recipients were included in the study period, and 161 patients (17.1%) received allografts from advanced-age donors. During the study period, the annual incidence of donation after circulatory heart transplantation with advanced-age donors substantially increased. The recipients with advanced-age donors had similar 90-day and 1-year post-transplant survivals compared with the recipients with younger donors. The comparable 90-day survival persisted in a propensity score-matched comparison. In the subgroup analysis among the recipients with advanced-age donors, the recipients aged 60 years or more had significantly reduced 90-day survival compared with the recipients aged less than 60 years. CONCLUSIONS: The use of appropriately selected donation after circulatory donors aged 40 years or more has similar survival compared with that of younger donors. With careful candidate risk stratification and selection, consideration of using donation after circulatory donors aged more than 40 years may further ameliorate ongoing organ shortage with comparable early post-transplant outcomes.

Outcomes of Impella 5.0 and 5.5 for cardiogenic shock: A single-center 137 patient experience.

BACKGROUND: This study evaluated the outcomes of patients with cardiogenic shock (CS) supported with Impella 5.0 or 5.5 and identified risk factors for in-hospital mortality. METHODS: Adults with CS who were supported with Impella 5.0 or 5.5 at a single institution were included. Patients were stratified into three groups according to their CS etiology: (1) acute myocardial infarction (AMI), (2) acute decompensated heart failure (ADHF), and (3) postcardiotomy (PC). The primary outcome was survival, and secondary outcomes included adverse events during Impella support and length of stay. Multivariable logistic regression was performed to identify risk factors for in-hospital mortality. RESULTS: One hundred and thirty-seven patients with CS secondary to AMI (n = 47), ADHF (n = 86), and PC (n = 4) were included. The ADHF group had the highest survival rates at all time points. Acute kidney injury (AKI) was the most common complication during Impella support in all 3 groups. Increased rates of AKI and de novo renal replacement therapy were observed in the PC group, and the AMI group experienced a higher incidence of bleeding requiring transfusion. Multivariable analysis demonstrated diabetes mellitus, elevated pre-insertion serum lactate, and elevated pre-insertion serum creatinine were independent predictors of in-hospital mortality, but the etiology of CS did not impact mortality. CONCLUSIONS: This study demonstrates that Impella 5.0 and 5.5 provide effective mechanical support for patients with CS with favorable outcomes, with nearly two-thirds of patients alive at 180 days. Diabetes, elevated pre-insertion serum lactate, and elevated pre-insertion serum creatinine are strong risk factors for in-hospital mortality.

Concomitant use of extracorporeal membrane oxygenation and percutaneous microaxial assist device support for cardiogenic shock.

Objectives: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) with concomitant percutaneous microaxial left ventricular assist device support is an emerging treatment modality for cardiogenic shock (CS). Survival outcomes by CS etiology with this support strategy have not been well described. Methods: This study was a retrospective, single-center analysis of patients with CS due to acute myocardial infarction (AMI-CS) or decompensated heart failure (ADHF-CS) supported with VA-ECMO with concomitant percutaneous microaxial left ventricular assist device support from December 2020 to January 2023. Results: A total of 44 patients were included (AMI-CS, n = 20, and ADHF-CS, n = 24). Patients with AMI-CS and ADHF-CS had similar survival at 90 days postdischarge (P = .267) with similar destinations after support (P = .220). Patients with AMI-CS initially supported with VA-ECMO were less likely to survive 90 days postdischarge (P = .038) when compared with other cohorts. Limb ischemia and acute kidney injury occurred more frequently in patients presenting with AMI-CS (P =.013; P = .030). Subanalysis of ADHF-CS patients into acute-on-chronic decompensated HF and de novo HF demonstrated no difference in survival or destination. Conclusions: VA-ECMO with concomitant percutaneous microaxial left ventricular assist device support can be used to successfully manage patients with CS. There is no difference in survival or destination for AMI-CS and ADHF-CS with this support strategy. AMI-CS patients with initial VA-ECMO support have increased mortality in comparison to other cohorts. Future multicenter studies are required to fully analyze the differences between AMI-CS and ADHF-CS with this support strategy.

Impact of post-transplant stroke and subsequent functional independence on outcomes following heart transplantation under the 2018 United States heart allocation system.

BACKGROUND: This study evaluates the clinical trends, risk factors, and effects of post-transplant stroke and subsequent functional independence on outcomes following orthotopic heart transplantation under the 2018 heart allocation system. METHODS: The United Network for Organ Sharing registry was queried to identify adult recipients from October 18, 2018 to December 31, 2021. The cohort was stratified into 2 groups with and without post-transplant stroke. The incidence of post-transplant stroke was compared before and after the allocation policy change. Outcomes included post-transplant survival and complications. Multivariable logistic regression was performed to identify risk factors for post-transplant stroke. Sub-analysis was performed to evaluate the impact of functional independence among recipients with post-transplant stroke. RESULTS: A total of 9,039 recipients were analyzed in this study. The incidence of post-transplant stroke was higher following the policy change (3.8% vs 3.1%, p = 0.017). Thirty-day (81.4% vs 97.7%) and 1-year (66.4% vs 92.5%) survival rates were substantially lower in the stroke cohort (p < 0.001). The stroke cohort had a higher rate of post-transplant renal failure, longer hospital length of stay, and worse functional status. Multivariable analysis identified extracorporeal membrane oxygenation, durable left ventricular assist device, blood type O, and redo heart transplantation as strong predictors of post-transplant stroke. Preserved functional independence considerably improved 30-day (99.2% vs 61.2%) and 1-year (97.7% vs 47.4%) survival rates among the recipients with post-transplant stroke (p < 0.001). CONCLUSIONS: There is a higher incidence of post-transplant stroke under the 2018 allocation system, and it is associated with significantly worse post-transplant outcomes. However, post-transplant stroke recipients with preserved functional independence have improved survival, similar to those without post-transplant stroke.

Improved waitlist and comparable post-transplant outcomes in simultaneous heart-kidney transplantation under the 2018 heart allocation system.

OBJECTIVE: This study aimed to investigate the clinical trends and the impact of the 2018 heart allocation policy change on both waitlist and post-transplant outcomes in simultaneous heart-kidney transplantation in the United States. METHODS: The United Network for Organ Sharing registry was queried to compare adult patients before and after the allocation policy change. This study included 2 separate analyses evaluating the waitlist and post-transplant outcomes. Multivariable analyses were performed to determine the 2018 allocation system's risk-adjusted hazards for 1-year waitlist and post-transplant mortality. RESULTS: The initial analysis investigating the waitlist outcomes included 1779 patients listed for simultaneous heart-kidney transplantation. Of these, 1075 patients (60.4%) were listed after the 2018 allocation policy change. After the policy change, the waitlist outcomes significantly improved with a shorter waitlist time, lower likelihood of de-listing, and higher likelihood of transplantation. In the subsequent analysis investigating the post-transplant outcomes, 1130 simultaneous heart-kidney transplant recipients were included, where 738 patients (65.3%) underwent simultaneous heart-kidney transplantation after the policy change. The 90-day, 6-month, and 1-year post-transplant survival and complication rates were comparable before and after the policy change. Multivariable analyses demonstrated that the 2018 allocation system positively impacted risk-adjusted 1-year waitlist mortality (sub-hazard ratio, 0.66, 95% CI, 0.51-0.85, P < .001), but it did not significantly impact risk-adjusted 1-year post-transplant mortality (hazard ratio, 1.03; 95% CI, 0.72-1.47, P = .876). CONCLUSIONS: This study demonstrates increased rates of simultaneous heart-kidney transplantation with a shorter waitlist time after the 2018 allocation policy change. Furthermore, there were improved waitlist outcomes and comparable early post-transplant survival after simultaneous heart-kidney transplantation under the 2018 allocation system.

Cardiogenic shock etiology and exit strategy impact survival in patients with Impella 5.5.

BACKGROUND: Despite historical differences in cardiogenic shock (CS) outcomes by etiology, outcomes by CS etiology have yet to be described in patients supported by temporary mechanical circulatory support (MCS) with Impella 5.5. OBJECTIVES: This study aims to identify differences in survival and post-support destination for these patients in acute myocardial infarction (AMI) and acute decompensated heart failure (ADHF) CS at a high-volume, tertiary, transplant center. METHODS: A retrospective review of patients who received Impella 5.5 at our center from November 2020 to June 2022 was conducted. RESULTS: Sixty-seven patients underwent Impella 5.5 implantation for CS; 23 (34%) for AMI and 44 (66%) for ADHF. AMI patients presented with higher SCAI stage, pre-implant lactate, and rate of prior MCS devices, and fewer days from admission to implantation. Survival was lower for AMI patients at 30 days, 90 days, and discharge. No difference in time to all-cause mortality was found when excluding patients receiving transplant. There was no significant difference in complication rates between groups. CONCLUSIONS: ADHF-CS patients with Impella 5.5 support have a significantly higher rate of survival than patients with AMI-CS. ADHF patients were successfully bridged to heart transplant more often than AMI patients, contributing to increased survival.

Concomitant Use of VA-ECMO and Impella Support for Cardiogenic Shock.

Background: VA-ECMO with concomitant Impella support (ECpella) is an emerging treatment modality for cardiogenic shock (CS). Survival outcomes by CS etiology with ECpella support have not been well-described. Methods: This study was a retrospective, single-center analysis of patients with cardiogenic shock due to acute myocardial infarction (AMI-CS) or decompensated heart failure (ADHF-CS) supported with ECpella from December 2020 to January 2023. Primary outcomes included 90-day survival post-discharge and destination after support. Secondary outcomes included complications post-ECpella support. Results: A total of 44 patients were included (AMI-CS, n = 20, and ADHF-CS, n = 24). Patients with AMI-CS and ADHF-CS had similar survival 90 days post-discharge (p = .267) with similar destinations after ECpella support (p = .220). Limb ischemia and acute kidney injury occurred more frequently in patients presenting with AMI-CS (p=.013; p = .030). Patients with initial Impella support were more likely to survive ECpella support and be bridged to transplant (p=.033) and less likely to have a cerebrovascular accident (p=.016). Sub-analysis of ADHF-CS patients into acute-on-chronic decompensated heart failure and de novo heart failure demonstrated no difference in survival or destination. Conclusion: ECpella can be used to successfully manage patients with CS. There is no difference in survival or destination for AMI-CS and ADHF-CS in patients with ECpella support. Patients with initial Impella support are more likely to survive ECpella support and bridge to transplant. Future multicenter studies are required to fully analyze the differences between AMI-CS and ADHF-CS with ECpella support.

Cardiac Catheterization via Direct Access of Venoarterial Extracorporeal Membrane Oxygenation Circuit.

Obtaining arterial access for cardiac catheterization can be both challenging and morbid in patients supported by venoarterial extracorporeal membrane oxygenation (VA-ECMO). While catheterization performed by obtaining endovascular access through the ECMO circuit itself has been described, all previous cases utilized a Y-connector and accessory tubing limb. We report a novel technique whereby arterial access was obtained directly via standard VA-ECMO arterial return tubing, through which coronary angiography was successfully performed in a 67-year-old woman. This technique may reduce the incidence of morbidity attendant with obtaining vascular accesses in patients on ECMO without requiring insertion of new circuit components.

Impact of 2018 allocation system change on outcomes in patients with durable left ventricular assist device as bridge to transplantation: A UNOS registry analysis.

BACKGROUND: This study compared outcomes of patients waitlisted for orthotopic heart transplantation with durable left ventricular assist devices (LVAD) before and after the October 18, 2018 heart allocation policy change. METHODS: The United Network of Organ Sharing database was queried to identify 2 cohorts of adult candidates with durable LVAD listed within seasonally-matched, equal-length periods before (old policy era [OPE]) and after the policy change (new policy era [NPE]). The primary outcomes were 2-year survival from the time of initial waitlisting, as well as 2-year post-transplant survival. Secondary outcomes included incidence of transplantation from the waitlist and de-listing due to either death or clinical deterioration. RESULTS: A total of 2,512 candidates were waitlisted, 1,253 within the OPE and 1,259 within the NPE. Candidates under both policies had similar 2-year survival after waitlisting, as well as a similar cumulative incidence of transplantation and de-listing due to death and/or clinical deterioration. A total of 2,560 patients were transplanted within the study period, 1,418 OPE and 1,142 within the NPE. Two-year post-transplant survival was similar between policy eras, however, the NPE was associated with a higher incidence of post-transplant stroke, renal failure requiring dialysis, and a longer hospital length of stay. CONCLUSIONS: The 2018 heart allocation policy has conferred no significant impact on overall survival from the time of initial waitlisting among durable LVAD-supported candidates. Similarly, the cumulative incidence of transplantation and waitlist mortality have also been largely unchanged. For those undergoing transplantation, a higher degree of post-transplant morbidity was observed, though survival was not impacted.

Clinical trends, risk factors, and temporal effects of post-transplant dialysis on outcomes following orthotopic heart transplantation in the 2018 United States heart allocation system.

BACKGROUND: This study evaluated the current clinical trends, risk factors, and temporal effects of post-transplant dialysis on outcomes following orthotopic heart transplantation after the 2018 United States adult heart allocation policy change. METHODS: The United Network for Organ Sharing (UNOS) registry was queried to analyze adult orthotopic heart transplant recipients after the October 18, 2018 heart allocation policy change. The cohort was stratified according to the need for post-transplant de novo dialysis. The primary outcome was survival. Propensity score-matching was performed to compare the outcomes between 2 similar cohorts with and without post-transplant de novo dialysis. The impact of post-transplant dialysis chronicity was evaluated. Multivariable logistic regression was performed to identify risk factors for post-transplant dialysis. RESULTS: A total of 7,223 patients were included in this study. Out of these, 968 patients (13.4%) developed post-transplant renal failure requiring de novo dialysis. Both 1-year (73.2% vs 94.8%) and 2-year (66.3% vs 90.6%) survival rates were lower in the dialysis cohort (p < 0.001), and the lower survival rates persisted in a propensity-matched comparison. Recipients requiring only temporary post-transplant dialysis had significantly improved 1-year (92.5% vs 71.6%) and 2-year (86.6 % vs 52.2%) survival rates compared to the chronic post-transplant dialysis group (p < 0.001). Multivariable analysis demonstrated low pretransplant estimated glomerular filtration (eGFR) and bridge with extracorporeal membrane oxygenation (ECMO) were strong predictors of post-transplant dialysis. CONCLUSIONS: This study demonstrates that post-transplant dialysis is associated with significantly increased morbidity and mortality in the new allocation system. Post-transplant survival is affected by the chronicity of post-transplant dialysis. Low pretransplant eGFR and ECMO are strong risk factors for post-transplant dialysis.

Heart Donation and Preservation: Historical Perspectives, Current Technologies, and Future Directions.

Heart transplantation has become the accepted treatment for advanced heart failure, with over 4000-5000 performed in the world annually. Although the number of yearly transplants performed has been increasing over the last decade, the number of candidates in need of transplantation continues to grow at an even faster rate. To distribute these scarce and precious resources equitably, donor heart placement is based on clinical need with priority given to those who are more critically ill. As a result, donors are matched with recipient candidates over increasingly farther distances, which may subject these organs to longer ischemic times. One of the mainstays of successful heart transplantation is successful organ preservation while the donor organ is ex vivo from the time of donor procurement to recipient implantation. In order to adapt to a new era of heart transplantation where organs are shared across wider ranges, preservation strategies must evolve to accommodate longer ischemia times while mitigating the harmful sequalae of ischemia-reperfusion injury. Additionally, in order to address the ever-growing supply demand mismatch of donor organs, evolving perfusion technologies may allow for further evaluation of donor grafts outside of conventional acceptance practices, thus enlarging the effective donor pool. Herein this review, we discuss the history of organ preservation, current strategies and modalities employed in current practice, along with developing technologies in preclinical stages. Lastly, we introduce the concept of donation after circulatory death (DCD), which has been until recently a largely unexplored avenue of heart donation that relies much on current preservation techniques.

Comparison of two individualized antithrombotic protocols in HeartWare HVAD recipients.

We previously reported low rates of pump thrombosis and hemorrhagic stroke, but increased bleeding, under our original antithrombosis protocol (P1) in HeartWare recipients. We designed and implemented a revised protocol (P2) to reduce complexity and bleeding. Thrombelastography and PFA-100 guide antiplatelet titration. Goals for P2 were altered to decrease antiplatelet use and anticoagulation intensity. We compared the incidence and rates of gastrointestinal bleeding (GIB), embolic (eCVA) and hemorrhagic (hCVA) stroke, pump thrombosis (PT), and total bleeding (GIB+hCVA), total thrombosis (eCVA+PT), and total events between P1 and P2. Laboratory and medication data were assessed. Patients with and without hemocompatibility-related adverse events (HRAEs) were compared. The study included 123 patients (P1: 65; P2: 58). GIB rate decreased (P1: 0.66; P2 0.30 EPPY, P = .003). CVA rates and incidence were statistically similar, although hCVA incidence increased (P1: 3%; P2: 12%, P = .06). Incidence (P1: 3%; P2: 16%, P = .02) and rate (P1: 0.03; P2: 0.12 EPPY, P = .08) of PT increased. Incidence and rate of overall HRAEs and thrombotic events were similar, while bleeding rate decreased (P1: 0.69; P2: 0.40 EPPY, P = .02). Twelve-month medication burden decreased. Compared to non-HRAE patients, patients with bleeding HRAEs had more antiplatelet and pentoxifylline use, but less statin use; and lower PFAs. Patients with thrombotic HRAEs had less dual antiplatelet use, lower INRs, R-times, and PFA-ADP values. A revised antithrombotic protocol decreased GIB and overall hemorrhagic HRAE rate and medication burden. Unfortunately, PT increased. Non-HRAE and HRAE patients differed in anticoagulation and antiplatelet intensity. These differences will guide the revision of P2.

Minimally Invasive Left Ventricular Assist Device Insertion Facilitates Subsequent Heart Transplant.

OBJECTIVE: We have observed that minimally invasive left ventricular assist device (LVAD) insertion leads to more facile re-entry and easier cardiac transplantation. We hypothesize minimally invasive LVAD implantation results in improved outcomes at the time of subsequent heart transplant. METHODS: All adults undergoing cardiac transplantation between October 2015 and March 2019 at our institution were retrospectively reviewed. Those bridged to transplantation with a HeartWare HVAD were identified and divided into 2 cohorts based upon the surgical approach: those who underwent HVAD placement by conventional sternotomy versus minimally invasive insertion via lateral thoracotomy and hemisternotomy (LTHS). Patient demographics, as well as perioperative transplant outcomes, including survival, length of stay (LOS), blood utilization, ischemic time, bypass time, and postoperative extracorporeal membrane oxygenation (ECMO) were compared between cohorts. RESULTS: Forty-two patients were bridged to heart transplant with a HVAD implanted via either sternotomy (n = 22) or LTHS technique (n = 20). Demographics were similar between groups. There was 1 predischarge death in the sternotomy group and none in the LTHS group. Body surface area, cardiopulmonary bypass time, ischemic time, ECMO utilization, and reoperation for bleeding were similar. Red blood cell units transfused were significantly lower in the LTHS cohort (3.0 [1.0-5.0] vs 6.0 [2.5-10.0] P = 0.046). The LTHS cohort had a significantly shorter hospital LOS (12.0 [11.0-28.0] vs 22.5 [15.7-41.7] P = 0.022) with a trend toward shorter intensive care unit LOS (6.0 [5.0-10.5] vs 11.0 [6.0-21.5] days P = 0.057). CONCLUSIONS: Minimally invasive HVAD implantation improves outcomes at subsequent heart transplantation, resulting in shorter LOS and less red cell transfusion. Larger multi-institutional studies are necessary to validate these findings.

A Minimally Invasive Approach to Left Ventricular Assist Device Insertion Facilitates Subsequent Explant.

A minimally invasive approach to left ventricular assist device (LVAD) insertion may benefit patients at the time of implant, but whether the approach to LVAD insertion influences the outcome of subsequent cardiovascular reoperations is unknown. Here we present the case of a 50-year-old male who underwent LVAD insertion through a minimally invasive approach and subsequently had left ventricular recovery. LVAD explant was performed without the use of any blood products or inotropic support. This case demonstrates that a minimally invasive approach to LVAD insertion may also facilitate subsequent device explant.

Emergency Splicing of Transected Ventricular Assist Device Driveline.

Left ventricular assist device (LVAD) driveline transection is an often fatal complication traditionally treated with salvage surgery. We present the case of a 70-year-old man who presented in cardiogenic shock after accidentally transecting his LVAD driveline. The driveline was emergently dissected at the bedside, all 6 internal wires were spliced, and his LVAD was restarted without morbidity. He subsequently underwent formal durable driveline splice by the device manufacturer 8 hours later and was discharged home uneventfully 28 hours after presentation. In this report we describe our novel, rapid, reproducible method for emergency HeartWare HVAD (Medtronic, Framingham, MA) driveline splicing, offering an alternative to surgical device exchange.

Total Artificial Heart as Rescue Therapy for Primary Graft Failure in an Infant.

An infant unable to be weaned from cardiopulmonary bypass after orthotopic heart transplantation was cannulated for extracorporeal membrane oxygenation. During the next 3 days, allograft failure and intracardiac thrombosis necessitated cardiectomy. To provide acute mechanical circulatory support, artificial atrial chambers were constructed with Gore-Tex conduits and PediMag centrifugal pumps were connected to each by Berlin Heart EXCOR cannulae. The PediMag pumps were subsequently exchanged for 10-mL Berlin Heart EXCOR pumps. After 60 days of support by total artificial heart, the patient was bridged successfully to a second heart transplant.

Red Blood Cell Mechanical Fragility Test for Clinical Research Applications.

Red blood cell (RBC) susceptibility to mechanically induced hemolysis, or RBC mechanical fragility (MF), is an important parameter in the characterization of erythrocyte membrane health. The rocker bead test (RBT) and associated calculated mechanical fragility index (MFI) is a simple method for the assessment of RBC MF. Requiring a minimum of 15.5 mL of blood and necessitating adjustment of hematocrit (Ht) to a "standard" value (40%), the current RBT is not suitable for use in most studies involving human subjects. To address these limitations, we propose a 6.5 mL reduced volume RBT and corresponding modified MFI (MMFI) that does not require prior Ht adjustment. This new method was assessed for i) correlation to the existing text, ii) to quantify the effect of Ht on MFI, and iii) validation by reexamining the protective effect of plasma proteins on RBC MF. The reduced volume RBT strongly correlated (r = 0.941) with the established large volume RBT at matched Hts, and an equation was developed to calculate MMFI: a numerical estimation (R2 = 0.923) of MFI if performed with the reduced volume RBT at "standard" (40%) Ht. An inversely proportional relationship was found between plasma protein concentration and RBC MF using the MMFI-reduced volume method, supporting previous literature findings. The new reduced volume RBT and modified MFI will allow for the measurement of RBC MF in clinical and preclinical studies involving humans or small animals.