Changes in Use of Left Ventricular Assist Devices as Bridge to Transplantation With New Heart Allocation Policy

Improving the Prioritization of Heart Transplantation Candidates for Optimal Clinical Outcomes: A Narrative Review

PURPOSE OF REVIEW

This narrative review evaluates the limitations of current heart transplantation allocation models, which prioritize medical urgency and waitlist time but fail to adequately predict long-term post-transplant outcomes. It aims to identify advanced metrics that can strengthen the prioritization framework while addressing persistent racial, geographic, and socioeconomic inequities in access to transplantation.

RECENT FINDINGS

Recent research indicates that incorporating frailty, nutritional status, immunological compatibility, and pulmonary hemodynamics into allocation frameworks can enhance the prediction of transplant outcomes. The growing use of mechanical circulatory support (MCS) as a bridge to transplantation provides stabilization for critically ill patients; however, disparities in access persist. Studies continue to emphasize the barriers faced by minority and pediatric populations, highlighting the need for expanded donor networks and improved matching criteria. This review highlights the necessity of shifting transplantation prioritization toward multidimensional candidate evaluations that consider both clinical complexity and long-term outcomes. Policy reforms aimed at addressing healthcare disparities and optimizing donor utilization are crucial for improving patient outcomes. Future research should focus on assessing the effectiveness of advanced allocation models, such as continuous distribution frameworks, to promote equitable and sustainable transplantation systems.

Machine Perfusion for Recovery of Brain Death Donor Hearts from Extended Distances

The emerging ex vivo machine perfusion (MP) enables the extension of ex situ intervals, potentially expanding the heart transplant (OHT) donor pool. From October 18, 2018, to June 30, 2023, isolated OHT using donation after brain death (DBD) from extended distances (>500 miles) were identified in the United Network for Organ Sharing database, and categorized into cold storage (non-MP, N = 1,212) and MP group (N = 152). The MP utilization rate for DBD hearts from extended distances surged from 0% in 2018 to 27.7% in 2023. Recipient characteristics including listing status were similar except for history of cardiac surgery (non-MP, 32% vs. MP, 41%, p = 0.019). The travel distance was longer in MP group (696 vs. 894 miles, p < 0.001), as was donor organ preservation time (4.42 vs. 6.27 hours, p < 0.001). One-year survival was similar between groups (non-MP, 93.0 ± 0.8% vs. MP, 90.5 ± 2.9%, p = 0.23). In multivariable Cox hazards models, MP was not associated with mortality (hazard ratio, 1.19; p = 0.60). Among MP cohort, survival was comparable between hearts transported between 500-999 miles (N = 112) and those over 1,000 miles (N = 40). The utilization of MP for DBD heart recovery allows for safe DBD recovery from extended distance with comparable survival to cold storage.

Changes in Donor Utilization and Outcomes for Patients Bridged With Durable Left Ventricular Assist Device

We studied the impact of the 2018 heart allocation policy change on donor characteristics and posttransplant outcomes of left ventricular assist device (LVAD)-bridged heart transplant (HT) recipients. Left ventricular assist device-bridged adult HT recipients from October 2014 to October 2022 in the United Network for Organ Sharing database were categorized into old allocation policy (OAP) and new allocation policy (NAP) cohorts. Baseline characteristics, posttransplant outcomes, and subgroup analyses of unstable and stable LVAD-bridged recipients were assessed. The study included 7,384 HT recipients; 4,345 (58.8%) were transplanted in the OAP era and 3,039 (41.2%) in the NAP era. Old allocation policy recipients were most frequently status 1A at transplantation (71.1%), whereas NAP recipients were most frequently status 3 (40.0%), and status 4 (31.9%). Median donor sequence number (DSN) was higher in the NAP versus OAP era (9 vs. 3, p < 0.001). On multivariable analysis, NAP recipients had 20% higher 1 year mortality compared to OAP (adjusted hazard ratio [aHR] = 1.20 [95% confidence interval {CI}: 1.04-1.40], p = 0.01). Status 1 or 2 recipients had 28% higher 1 year mortality compared to status 1A (aHR = 1.28 [95% CI: 1.01-1.63], p = 0.04). Status 1 and 2 LVAD-supported recipients had higher mortality following the 2018 allocation change, indicating the need for closer surveillance of LVAD-bridged patients who may decompensate on the waitlist.

Impact of Heart Transplant Allocation Change on Waitlist Mortality and Posttransplant Mortality in Patients With Left Ventricular Assist Devices

BACKGROUND

In October 2018, the US heart transplant (HT) allocation system was revised giving patients with left ventricular assist device (LVAD) intermediate priority status. Few studies have examined the impact of this policy change on outcomes among patients with LVAD. We sought to determine how the allocation change impacted waitlist and posttransplant mortality in patients with LVAD.

METHODS

We retrospectively assessed the United Network for Organ Sharing registry for patients with LVAD who were listed for or underwent HT between October 2016 and October 2021. We evaluated waitlist mortality using competing risks analysis and a multivariable Fine-Gray model, and posttransplant mortality using Kaplan-Meier survival analysis and a multivariate proportional hazards model.

RESULTS

We analyzed data from 3835 patients with LVAD listed for HT and 3486 patients with LVAD who underwent HT during the study period. Listing for HT preallocation change was significantly associated with an increased risk of waitlist mortality (Gray P=0.0058) compared with postallocation change. After adjustment for covariates, mortality differences by listing era were attenuated, but LVAD brand was significantly associated with waitlist mortality (HM3 versus HMII; hazard ratio, 0.38 [95% CI, 0.21-0.69]; P=0.002; HVAD versus HMII; hazard ratio, 0.79 [95% CI, 0.48-1.30]; P=0.36; overall P=0.004). In contrast, HT postallocation change was associated with increased posttransplant mortality (log-rank P=0.0172) compared with preallocation change. In a multivariable analysis, the association with posttransplant mortality between transplant eras was attenuated, but ischemic time (hazard ratio, 1.16 [95% CI, 1.07-1.26]; P<0.001) and status at time of HT (Status 1-3 versus 4; hazard ratio, 1.29 [95% CI, 1.04-1.61]; P=0.02) were significantly associated with posttransplant mortality.

CONCLUSIONS

Among patients with LVAD, lower waitlist mortality postallocation change was likely driven by improved LVAD technology. Higher posttransplant mortality following the allocation change was largely attributable to longer ischemic times and patient acuity.

Comparison of continuous flow centrifugal left ventricular assist devices as a bridge to transplant strategy in a low organ donation environment: single center experience

OBJECTIVE

In patients with advanced heart failure, heart transplantation is currently the most effective treatment. However, in a low-organ donation environment, it is usually necessary to proceed in long-term mechanical circulatory support through left ventricular assist device (LVAD) implantation as bridge-to-transplantation.

METHODS

The study included all patients with advanced heart failure who underwent continuous flow LVAD implantation as a bridge to transplant strategy in our center (n = 68). Following LVAD implantation and for the period that patients were on LVAD support, pump thrombosis, strokes, gastrointestinal bleeding, and right heart failure occurrence rates were recorded. Outcomes were compared between patients implanted with HeartMate 3 (HM3) and HeartWare LVADs, as well as between patients who did reach heart transplantation (HTx group) and those who did not (noHTx group).

RESULTS

A total of 35 out of 68 patients underwent heart transplantation at a mean time of 691 ± 457 days; 41 received a HeartWare and 27 a HM3 device. HM3 patients had significantly better survival (p = 0.010) and lower complication rates (p = 0.025). In addition, the noHTx group had significantly higher complication rates compared with the HTx group (p = 0.00041). The 5-year estimated Kaplan-Meier survival rate following heart transplantation was 77%.

CONCLUSION

Patients with advanced heart failure gain substantial benefit from LVADs awaiting heart transplantation. In a low organ donation environment, the need for reliable LVADs can further improve the outcomes through the reduction of complications provided by current devices.

The impact of the OPTN policy change on patients with a durable left ventricular assist device and chronic kidney disease: Analysis of the UNOS database

BACKGROUND

The Organ Procurement and Transplantation Network (OPTN) implemented modifications in 2018 to the adult heart transplant allocation system to better stratify the most medically urgent transplant candidates. We evaluated the impact of these changes on patients supported by a durable left ventricular assist device (LVAD) with chronic kidney disease (CKD).

OBJECTIVE

To evaluate the impact of the OPTN policy change on patients supported by durable left ventricular assist devices (LVAD) with chronic kidney disease (CKD).

METHODS

We performed an analysis of patients from the United Network of Organ Sharing Database supported by durable LVAD listed for a heart transplant (HT) between October 17, 2016 and September 30, 2021. Patients were divided into two groups: pre- and postpolicy, depending on whether they were listed on or prior to October 17, 2018. Patients who were on dialysis prior to surgery or discharge were excluded from the analysis. Patients with simultaneous heart and kidney transplants were excluded. Patients who were listed for transplant prepolicy change but transplanted postpolicy change were excluded. This cohort was then subdivided into degrees of CKD based on estimated glomerular filtration rate (eGFR), which resulted in 678 patients (23.7%) in Stage 1 (GFR ≥89.499) (Prepolicy: 345, Postpolicy: 333), 1233 (43.1%) in Stage 2 (89.499 > GFR ≥ 59.499) (Prepolicy: 618, Postpolicy: 615), 613 (21.4%) in Stage 3a (59.499 > GFR ≥ 44.499) (Prepolicy: 291, Postpolicy: 322), 294 (10.3%) in Stage 3b (44.499 > GFR ≥ 29.499) (Prepolicy: 143, Postpolicy: 151), 36 (1.3%) in Stage 4 (29.499 > GFR ≥ 15) (Prepolicy: 21, Postpolicy: 15), and 9 (0.3%) in Stage 5 (15 > GFR) (Prepolicy: 4, Postpolicy: 5). The primary outcome was 1-year and 2-year post-HT survival.

RESULTS

There were 2863 patients who met the study criteria (1422 prepolicy, 1441 postpolicy). Overall survival, regardless of CKD stage, was lower following the policy change (p < 0.01). There was a similar risk of primary graft failure (PGF) in the pre- and postpolicy period (1.8% vs. 1.2%, p = 0.26). 1-year overall survival was 93% (91, 94) and 89% (87, 91) in the pre- and postpolicy periods, respectively. 2-year overall survival was 89% (88, 91) and 85% (82, 87) in the pre- and postpolicy periods, respectively. For CKD Stages 1, 2, 3a, 3b, 4, and 5, 1 -year survival was 93% (91, 95), 92% (90,93), 89% (86, 91), 89% (86, 93), 80% (68, 94), and 100% (100, 100), respectively. For CKD Stages 1, 2, 3a, 3b, 4, and 5, 2-year survival was 91% (88, 93), 88% (86, 90), 84% (81, 88), 84% (80, 89), 73% (59, 90), and 100% (100, 100), respectively. Patients with CKD 1 and 2 had better survival compared to those with CKD 3 (p < 0.01) and CKD 4 and 5 (p = 0.03) in the pre- and postpolicy periods. Patients with CKD 3 did not have a survival advantage over those with CKD 4 and 5 (p = 0.25). On cox regression analysis, advancing degrees of CKD were associated with an increased risk of mortality.

CONCLUSIONS

Patients with LVAD support had decreased overall survival after the OPTN policy change. Patients with more advanced CKD had lower survival than patients without advanced CKD, though they were not impacted by the OPTN policy change.

Early outcomes in heart transplantation using donation after circulatory death donors in patients bridged with durable left ventricular assist devices

OBJECTIVE

Donation after circulatory death heart transplantation potentially increases donor allografts, especially for patients with lower listing status. We assessed the outcomes of donation after circulatory death heart transplantation in patients bridged with durable left ventricular assist devices.

METHODS

The United Network for Organ Sharing database was queried for adult heart transplants using donation after circulatory death donors from 2019 to 2022. Patients were stratified between those with durable left ventricular assist devices and those with intra-aortic balloon pump, inotropic, or no bridging support (control group). Primary outcome was 1-year mortality. Secondary end points were hospital length of stay, stroke, pacemaker implantation, dialysis, and acute rejection before discharge.

RESULTS

A total of 160 left ventricular assist device recipients and 311 control recipients met study inclusion criteria. Recipients bridged with left ventricular assist devices were younger (55 vs 58 years, P < .001) with lower body mass index (28.3 vs 30.3, P < .001), longer waitlist times (112 vs 34 days, P < .001), longer out of body times (5.7 vs 4.6 hours, P < .001), and less frequent normothermic regional perfusion (31% vs 40%, P = .049). Patients with left ventricular assist devices commonly underwent transplantation at United Network for Organ Sharing status 3 and 4 (92%), whereas control patients underwent transplantation at status 2 (27%), status 3 (10%), status 4 (30%), or status 6 (30%). Kaplan-Meier analysis showed no difference in 1-year mortality between groups (P = .34). However, acute rejection was higher in the unadjusted left ventricular assist device cohort (26% vs 13%, P < .001). On multivariable logistic regression, left ventricular assist device was an independent predictor of acute rejection (odds ratio, 2.21, 95% CI, 1.32-3.69, P = .002).

CONCLUSIONS

Durable left ventricular assist devices may be associated with a higher risk of developing an early inflammatory response in donation after circulatory death heart transplantation; however, 1-year survival was similar between groups.

Three-Year Left Ventricular Assist Device Outcomes and Strategy After Heart Transplant Allocation Score Change

The United Network for Organ Sharing (UNOS) adopted new criteria for the heart allocation score on October 18, 2018 to reflect the changing trends of candidates' mortality while awaiting transplant. We examined the impact of these policy changes on rates of left ventricular assist device (LVAD) implantation and outcomes after transplant from a relatively newer UNOS database. The UNOS registry was used to identify first-time adult heart recipients with LVAD at listing or transplant who underwent transplantation between January 1, 2016 and March 10, 2020. Survival data were collected through March 30, 2023. Those listed before October 18, 2018 but transplanted after were excluded. Patients were divided into before or after change groups. Demographics and clinical parameters were compared. Survival was analyzed with Kaplan-Meier curves and log-rank tests. A p <0.05 was considered significant. We identified 4,387 heart recipients with LVAD in the before (n = 3,606) and after (n = 781) score change eras. The after group had a lower rate of LVAD implantation while listed than the before group (20.4% vs 34.9%, p <0.0001), and were more likely to be female (25.1% vs 20.2%, p = 0.002); in both groups, most recipients (62.8%) were white. There was significantly farther distance from the donor hospital to transplant center in the after group (264.4 NM vs 144.2 NM, p <0.0001) and decreased waitlist days (84.9 ± 105.1 vs 369.2 ± 459.5, p <0.0001). Recipients in the after group were more likely to use extracorporeal membrane oxygenation (3.7% vs 0.5%, p <0.0001) and intravenous inotropes (19.1% vs 7.5%, p <0.0001) and receive a Centers for Disease Control and Prevention increased risk donor organ (37.9% vs 30.5%, p <0.0001). Survival at 3 years was comparable between the 2 groups. The allocation score change in 2018 yielded considerable changes in mechanical circulatory support device implantation strategy and outcomes. The rate of LVAD implantation decreased with increased utilization of temporary mechanical circulatory support devices.

Durable left ventricular assist devices as a bridge to transplantation: what to expect along the way?

INTRODUCTION

The scarcity of donors coupled with the improvements in left ventricular assist devices (LVAD) technology has led to the use of LVAD as a bridge to transplantation (BTT).

AREAS COVERED

The authors provide an overview of the current status of LVAD BTT implantation with special focus ranging from patient selection and pre-implantation optimization to post-transplant outcomes.

EXPERT OPINION

The United Network for Organ Sharing 2018 policy amendment resulted in a significant reduction in the number of LVADs used for BTT in the US. To overcome this issue, modifications in the US allocation policy to consider factors such as days on device support, age, and type of complications may be necessary to potentially increase implantation rates.

Bridge to Transplantation: Policies Impact Practices

Since the development of the first heart allocation system in 1988 to the most recent heart allocation system in 2018, the road to heart transplantation has continued to evolve. Policies were shaped with advances in temporary and durable left ventricular assist devices as well as prioritization of patients based on degree of illness. Herein, we review the changes in the heart allocation system over the past several decades and the impact of practice patterns across the United States.

Prevention and rehabilitation after heart transplantation: A clinical consensus statement of the European Association of Preventive Cardiology, Heart Failure Association of the ESC, and the European Cardio Thoracic Transplant Association, a section of ESOT

Little is known either about either physical activity patterns, or other lifestyle-related prevention measures in heart transplantation (HTx) recipients. The history of HTx started more than 50 years ago but there are still no guidelines or position papers highlighting the features of prevention and rehabilitation after HTx. The aims of this scientific statement are (i) to explain the importance of prevention and rehabilitation after HTx, and (ii) to promote the factors (modifiable/non-modifiable) that should be addressed after HTx to improve patients' physical capacity, quality of life and survival. All HTx team members have their role to play in the care of these patients and multidisciplinary prevention and rehabilitation programmes designed for transplant recipients. HTx recipients are clearly not healthy disease-free subjects yet they also significantly differ from heart failure patients or those who are supported with mechanical circulatory support. Therefore, prevention and rehabilitation after HTx both need to be specifically tailored to this patient population and be multidisciplinary in nature. Prevention and rehabilitation programmes should be initiated early after HTx and continued during the entire post-transplant journey. This clinical consensus.

Prevention and Rehabilitation After Heart Transplantation: A Clinical Consensus Statement of the European Association of Preventive Cardiology, Heart Failure Association of the ESC, and the European Cardio Thoracic Transplant Association, a Section of ESOT

Little is known either about either physical activity patterns, or other lifestyle-related prevention measures in heart transplantation (HTx) recipients. The history of HTx started more than 50 years ago but there are still no guidelines or position papers highlighting the features of prevention and rehabilitation after HTx. The aims of this scientific statement are (i) to explain the importance of prevention and rehabilitation after HTx, and (ii) to promote the factors (modifiable/non-modifiable) that should be addressed after HTx to improve patients' physical capacity, quality of life and survival. All HTx team members have their role to play in the care of these patients and multidisciplinary prevention and rehabilitation programmes designed for transplant recipients. HTx recipients are clearly not healthy disease-free subjects yet they also significantly differ from heart failure patients or those who are supported with mechanical circulatory support. Therefore, prevention and rehabilitation after HTx both need to be specifically tailored to this patient population and be multidisciplinary in nature. Prevention and rehabilitation programmes should be initiated early after HTx and continued during the entire post-transplant journey. This clinical consensus statement focuses on the importance and the characteristics of prevention and rehabilitation designed for HTx recipients.

"Durable left ventricular assist devices as a bridge to transplantation in The Old and The New World"

Heart transplantation remains the gold standard treatment for end-stage heart failure patients without contraindications. However, limited donor availability and long wait times have created a need for left ventricular assist devices (LVAD) to be used as a bridge to transplantation in appropriately selected patients. Improvements in LVAD technology have resulted in improved short- and long-term outcomes, further supporting the use of these devices for a bridge-to-transplant (BTT) indication. LVAD utilization as BTT exhibits notable disparities worldwide, mainly due to variations in organ availability, allocation policies, and financial constraints. Although Europe has experienced a consistent increase in the use of LVAD for this purpose, the United Network for Organ Sharing 2018 policy amendment resulted in a significant reduction in the number of LVADs used for BTT in the US. To overcome this issue, modifications in the US allocation policy to consider factors such as days on device support, age, and type of complications may be necessary to potentially increase implantation rates.The authors provide an overview comparing the current state of heart transplantation in the US and Europe, with a particular focus on how distinct allocation policies and organ availability impact medical practices. Additionally, the review will examine critical aspects ranging from patient selection and pre-implantation optimization to post-transplant outcomes.

Discovery of novel natural cardiomyocyte protectants from a toxigenic fungus Stachybotrys chartarum

Stachybatranones A-F (1a/1b and 2-6) and three known analogues, namely methylatranones A and B (7 and 8) and atranone B (9), were isolated and identified from a toxigenic fungus Stachybotrys chartarum. Their structures and absolute configurations were elucidated via the extensive spectroscopic data, comparison of the experimental electronic circular dichroism (ECD) data, and single-crystal X-ray diffraction analyses. Structurally, compounds 2-6 belonged to a rare class of C-alkylated dolabellanes, featuring a unique five-membered hemiketal ring and a γ-butyrolactone moiety both fused to an 11-membered carbocyclic system, while compound 1 (1a/1b) represented the first example of a 5-11-6-fused atranone possessing a 2,3-butanediol moiety. The cardiomyocyte protective activity assay revealed that compounds 1-9 ameliorated cold ischemic injury at 24 h post cold ischemia (CI), with compounds 1 and 4 acting in a dose-dependent manner. Moreover, compound 1 prevented cold ischemia induced dephosphorylation of PI3K and AKT acting in a dose-dependent manner. In this study, a new class of natural products were found to protect cardiomyocytes against cold ischemic injury, providing a potential option for the development of novel cardioprotectants in heart transplant medicine.

Outcomes of treatment for deep left ventricular assist device infection

OBJECTIVE

Among left ventricular assist device patients, the most commonly infected component is the drive line, which can be managed with antibiotics and local debridement. Infection of intrathoracic device components is less common but more difficult to manage. Herein we describe the incidence of deep device infection (DDI) at our center as well as management and outcomes.

METHODS

We retrospectively reviewed 658 patients who underwent implantable left ventricular assist device insertion with HeartMate 2 (Abbott) or HeartMate 3 (Abbott) devices between January 2004 and June 2021. DDI was defined according to radiographic and clinical criteria. Cumulative incidence was calculated using a Fine-Gray subdistribution model; survival analysis was performed using the method of Kaplan and Meier.

RESULTS

There were 32 (4.8%) DDIs during this study period. Drive line infection and re-exploration for bleeding were associated with development of DDI. Cumulative incidence of DDI increased over time, affecting 11% (7%-18%) at 5 years. The dominant microbes involved in DDI were Pseudomonas aeruginosa (19%) and methicillin-resistant Staphylococcus aureus (13%). Nineteen patients (59%) with device infection underwent device exchange, 6 (19%) underwent initial transplant, and 7 (22%) were treated solely with debridement and antibiotics. Of those who underwent device exchange, 12 (63%) developed reinfection of their new device and 6 underwent subsequent heart transplant. Patients who underwent transplantation for management of device infection had improved 5-year survival (80% vs 11%; P = .01) but 3 patients (25%) developed deep sternal wound infection after transplant.

CONCLUSIONS

DDI is a rare but challenging complication in this destination era. Heart transplantation is the preferred management strategy for eligible patients but infectious complication is common.

Early Outcomes in Patients With LVAD Undergoing Heart Transplant via Use of the SherpaPak Cardiac Transport System

BACKGROUND

Heart transplant (HT) in recipients with left ventricular assist devices (LVADs) is associated with poor early post-HT outcomes, including primary graft dysfunction (PGD). As complicated heart explants in recipients with LVADs may produce longer ischemic times, innovations in donor heart preservation may yield improved post-HT outcomes. The SherpaPak Cardiac Transport System is an organ preservation technology that maintains donor heart temperatures between 4 °C and 8 °C, which may minimize ischemic and cold-induced graft injuries. This analysis sought to identify whether the use of SherpaPak versus traditional cold storage was associated with differential outcomes among patients with durable LVAD undergoing HT.

METHODS

Global Utilization and Registry Database for Improved Heart Preservation-Heart (NCT04141605) is a multicenter registry assessing post-HT outcomes comparing 2 methods of donor heart preservation: SherpaPak versus traditional cold storage. A retrospective review of all patients with durable LVAD who underwent HT was performed. Outcomes assessed included rates of PGD, post-HT mechanical circulatory support use, and 30-day and 1-year survival.

RESULTS

SherpaPak (n=149) and traditional cold storage (n=178) patients had similar baseline characteristics. SherpaPak use was associated with reduced PGD (adjusted odds ratio, 0.56 [95% CI, 0.32-0.99]; P=0.045) and severe PGD (adjusted odds ratio, 0.31 [95% CI, 0.13-0.75]; P=0.009), despite an increased total ischemic time in the SherpaPak group. Propensity matched analysis also noted a trend toward reduced intensive care unit (SherpaPak 7.5±6.4 days versus traditional cold storage 11.3±18.8 days; P=0.09) and hospital (SherpaPak 20.5±11.9 days versus traditional cold storage 28.7±37.0 days; P=0.06) lengths of stay. The 30-day and 1-year survival was similar between groups.

CONCLUSIONS

SherpaPak use was associated with improved early post-HT outcomes among patients with LVAD undergoing HT. This innovation in preservation technology may be an option for HT candidates at increased risk for PGD.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04141605.

Predictors of Survival After Heart Transplant in the New Allocation System: A UNOS Database Analysis

Clinical predictors of posttransplant graft loss since the United Network for Organ Sharing (UNOS) heart allocation system change have not been well characterized. Single organ adult heart transplants from the UNOS database were identified (n = 10,252) and divided into a test cohort (n = 6,869, 67%) and validation cohort (n = 3,383, 33%). A Cox regression analysis was performed on the test cohort to identify recipient and donor risk factors for posttransplant graft loss. Based on the risk factors, a score (max 16) was developed to classify patients in the validation cohort into risk groups of low (≤1), mid (2-3), high (≥4) risk. Recipient factors of advanced age, Black race, recipient blood group O, diabetes, etiology of heart failure, renal dysfunction, elevated bilirubin, redo-transplantation, elevated pulmonary artery pressure, transplant with a durable ventricular assist device, or transplant on extracorporeal membrane oxygenation (ECMO) or ventilator were associated with more posttransplant graft loss. Donor factors of ischemic time and donor age were also associated with outcomes. One year graft survival for the low-, mid-, high-risk groups was 94%, 91%, and 85%, respectively. In conclusion, easily obtainable clinical characteristics at time of heart transplant can predict posttransplant outcomes in the current era.

Left Ventricular Assist Device Use in Minorities: An Analysis of the National Inpatient Sample

Minorities are less likely to receive a left ventricular assist device (LVAD). This, however, is based on total implant data. By examining rates of LVAD implant among patients admitted with heart failure complicated by cardiogenic shock, we sought to further elucidate LVAD utilization rates and racial disparities. Utilizing the National Inpatient Sample from 2013 to 2019, all patients admitted with a primary diagnosis of heart failure complicated by cardiogenic shock were included for analysis. Those who then received an LVAD during that hospitalization defined the LVAD utilization which was examined for any racial disparities. Left ventricular assist device utilization was low across all racial groups with no significant difference noted in univariate analysis. Non-Hispanic Blacks had the highest length of stay (LOS), the highest proportion of discharge to home (71.52%), and the lowest inpatient mortality (6.33%). Multivariable modeling confirmed the relationship between race and LOS; however, no differences were noted in mortality. Non-Hispanic Blacks were found to be less likely to receive an LVAD; however, when controlling for payer, median household income, and comorbidities, this relationship was no longer seen. Left ventricular assist devices remain an underutilized therapy in cardiogenic shock. When using a multivariable model, race does not appear to affect LVAD utilization.

The Society of Thoracic Surgeons Intermacs 2023 Annual Report: Focus on Magnetically Levitated Devices

The 14th Annual Report from The Society of Thoracic Surgeons (STS) Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs) describes outcomes of 27,493 patients with a continuous-flow left ventricular assist device (LVAD) from the past decade (2013-2022). In 2022, 2517 primary LVADs were implanted, of which 2512 (99.8%) were fully magnetically levitated (Mag-Lev) devices. This shift to nearly exclusive use of a Mag-Lev device led us to examine its outcomes compared with contemporary (2018-2022) and historical (2013-2017) non-Mag-Lev cohorts. Patients supported by a Mag-Lev device (n = 10,920) had a higher 1- and 5-year survival of 86% (vs 79% and 81%, P < .0001) and 64% (vs 44% and 44%, P < .0001), respectively, than those receiving non-Mag-Lev devices during the contemporary and historical eras. Over 5 years, freedom from gastrointestinal bleeding (72% vs 60%, P < .0001), stroke (87% vs 67%, P < .0001), and device malfunction/pump thrombus (83% vs 54%, P < .0001), but not device-related infection (61% vs 64%, P = .93), was higher with Mag-Lev devices compared with non-Mag-Lev support during the contemporary era. In this large primacy cohort of real-world patients with advanced heart failure, this report underscores marked improvements in short- and intermediate-term survival and reduction of adverse events with a contemporary Mag-Lev LVAD.

Outcomes of Patients With Left Ventricular Assist Devices Requiring Intermittent Hemodialysis: Single-Center Cohort, Systematic Review, and Individual-Participant Data Meta-Analysis

Patients with left ventricular assist devices (LVADs) who require intermittent hemodialysis (iHD) are considered to have a poor prognosis despite a paucity of supportive evidence, mostly from small single-center cohorts and extrapolations from studies of patients who received continuous renal replacement therapy but no iHD. We conducted a systematic review and individual-participant-data meta-analysis of the literature including our single-center cohort to examine the outcomes of patients initiated on iHD following LVAD implantation. Sixty-four patients from 5 cohorts met selection criteria (age 57.5 [46-64.5] years, 87% HeartMate II, mostly bridge to transplantation). Follow-up after iHD initiation was 87.5 (38.5-269.5) days, although it was considerably longer in our center than in other cohorts (601.5 [93-1559] days vs 65 [26-180] days, P = 0.0007). The estimated median survival was 308 (76-912.5) days and varied significantly among cohorts, ranging from 60 (57-65) to 838 (103-1872) days (P = 0.0096). Twelve (18.8%) patients achieved either heart transplantation (HT) or remission during follow-up. Patients who received HT had an 8-fold longer estimated median survival (1972 [799-1972] days vs 244 [64-838] days, P = 0.0112). Being from a more recent cohort was associated with better 1-year survival. Renal recovery occurred in eight patients (13.1%) at 30 days and its cumulative incidence increased to 73% (27/37 patients with available data) at 1 year. Most patients initiated on iHD after LVAD experienced renal recovery within the first year after implantation. Improved survival was observed for patients who received HT and in those from more recent cohorts. Some patients were able to survive on LVAD and iHD support for several years.

The Year in Cardiothoracic and Vascular Anesthesia: Selected Highlights From 2023

This special article is the 16th in an annual series for the Journal of Cardiothoracic and Vascular Anesthesia. The authors thank the editor-in-chief, Dr. Kaplan, and the editorial board for the opportunity to continue this series, namely the research highlights of the past year in the specialty of cardiothoracic and vascular anesthesiology. The major themes selected for 2023 are outlined in this introduction, and each highlight is reviewed in detail in the main article. The literature highlights in the specialty for 2023 begin with an update on perioperative rehabilitation in cardiothoracic surgery, with a focus on novel methods to best assess patients in the preoperative and postoperative periods, and the impact of rehabilitation on outcomes. The second major theme is focused on cardiac surgery, with the authors discussing new insights into inhaled pulmonary vasodilators, coronary revascularization surgery, and discussion of causes of coronary graft failure after surgery. The third theme is focused on cardiothoracic transplantation, with discussions focusing on bridge-to-transplantation strategies. The fourth theme is focused on mechanical circulatory support, with discussions focusing on both temporary and durable support. The fifth and final theme is an update on medical cardiology, with a focus on outcomes of invasive approaches to heart disease. The themes selected for this article are only a few of the diverse advances in the specialty during 2023. These highlights will inform the reader of key updates on various topics, leading to improved perioperative outcomes for patients with cardiothoracic and vascular disease.

Use of a surgically implanted, nondischargeable, extracorporeal continuous flow circulatory support system as a bridge to heart transplant

INTRODUCTION AND OBJECTIVES

We aimed to describe the clinical outcomes of the use of the CentriMag acute circulatory support system as a bridge to emergency heart transplantation (HTx).

METHODS

We conducted a descriptive analysis of the clinical outcomes of consecutive HTx candidates included in a multicenter retrospective registry who were treated with the CentriMag device, configured either for left ventricular support (LVS) or biventricular support (BVS). All patients were listed for high-priority HTx. The study assessed the period 2010 to 2020 and involved 16 transplant centers around Spain. We excluded patients treated with isolated right ventricular support or venoarterial extracorporeal membrane oxygenation without LVS. The primary endpoint was 1-year post-HTx survival.

RESULTS

The study population comprised 213 emergency HTx candidates bridged on CentriMag LVS and 145 on CentriMag BVS. Overall, 303 (84.6%) patients received a transplant and 53 (14.8%) died without having an organ donor during the index hospitalization. Median time on the device was 15 days, with 66 (18.6%) patients being supported for> 30 days. One-year posttransplant survival was 77.6%. Univariable and multivariable analyses showed no statistically significant differences in pre- or post-HTx survival in patients managed with BVS vs LVS. Patients managed with BVS had higher rates of bleeding, need for transfusion, hemolysis and renal failure than patients managed with LVS, while the latter group showed a higher incidence of ischemic stroke.

CONCLUSIONS

In a setting of candidate prioritization with short waiting list times, bridging to HTx with the CentriMag system was feasible and resulted in acceptable on-support and posttransplant outcomes.

Post-transplant survival with pre-transplant durable continuous-flow mechanical circulatory support in a Swiss cohort of heart transplant recipients

BACKGROUND

Worldwide, almost half of all heart transplantation candidates arrive today at their transplant operation with durable continuous-flow mechanical circulatory support (CF-MCS). This evolution is due to a progressive increase of waiting list time and hence an increased risk of haemodynamic worsening. Longer duration of CF-MCS is associated with a higher risk of device-related complications with potential adverse impact on post-transplant outcome as suggested by recent results from the United Network of Organ Sharing of the United States.

METHODS

A 2-centre Swiss heart transplantation programme conducted a retrospective observational study of consecutive patients of theirs who underwent a transplant in the period 2008-2020. The primary aim was to determine whether post-transplant all-cause mortality is different between heart transplant recipients without or with pre-transplant CF-MCS. The secondary outcome was the acute cellular rejection score within the first year post-transplant.

RESULTS

The study participants had a median age of 54 years; 38/158 (24%) were females. 53/158 study participants (34%) had pre-transplant CF-MCS with a median treatment duration of 280 days. In heart transplant recipients with pre-transplant CF-MCS, the prevalence of ischaemic cardiomyopathy was higher (51 vs 32%; p = 0.013), the left ventricular ejection fraction was lower (20 vs 25; p = 0.047) and pulmonary vascular resistance was higher (2.3 vs 2.1 Wood Units; p = 0.047). Over the study period, the proportion of heart transplant recipients with pre-transplant CF-MCS and the duration of pre-transplant CF-MCS treatment increased (2008-2014 vs 2015-2020: 22% vs 45%, p = 0.009; increase of treatment days per year: 34.4 ± 11.2 days, p = 0.003; respectively). The primary and secondary outcomes were not different between heart transplant recipients with pre-transplant CF-MCS or direct heart transplantation (log-rank p = 0.515; 0.16 vs 0.14, respectively; p = 0.81).

CONCLUSION

This data indicates that the strategy of pre-transplant CF-MCS with subsequent orthotopic heart transplantation provides post-transplant outcomes not different to direct heart transplantation despite the fact that the duration of pre-transplant assist device treatment has progressively increased.

A call to action in thoracic transplant surgical training

Thoracic organ recovery and implantation is increasing in complexity. Simultaneously the logistic burden and associated cost is rising. An electronic survey distributed to the surgical directors of thoracic transplant programs in the United States indicated dissatisfaction amongst 72% of respondents with current procurement training and 85% of respondents favored a process for certification in thoracic organ transplantation. These responses highlight concerns for the current paradigm of training in thoracic transplantation. We discuss the implications of advancements in organ retrieval and implant for surgical training and propose that the thoracic transplant community might address the need through formalized training in procurement and certification in thoracic transplantation.

Association between calculated panel reactive antibody and waitlist outcomes in the 2018 heart allocation system

BACKGROUND

The impact of heart transplant (HT) waitlist candidate sensitization on waitlist outcomes in the US is unknown.

METHODS

Adult waitlist outcomes in OPTN (October 2018-September 2022) by calculated panel reactive antibody (cPRA) were modeled to identify thresholds of clinical significance. The primary outcome was the rate of HT by cPRA category (low: 0-35, middle: >35-90, high: >90) assessed using multivariable competing risk analysis (compete: waitlist removal for death or clinical deterioration). The secondary outcome was waitlist removal for death or clinical deterioration.

RESULTS

The elevated cPRA categories were associated with lower rates of HT. Candidates in the middle (35-90) and high cPRA categories (>90) had an adjusted 24% lower rate (hazard ratio (HR) 0.86, 95% confidence interval (CI) 0.80-0.92) and 61% lower rate (HR 0.39 95% CI. 0.33-0.47) of HT than the lowest category, respectively. Waitlist candidates in the high cPRA category listed in the top acuity strata (Statuses 1, 2) had increased rates of delisting for death or deterioration compared to those in the low cPRA category (adjusted HR 2.9, 95% CI 1.5-5.5), however, elevated cPRA (middle, high) was not associated with an increased rate of death and delisting when the cohort was considered as a whole.

CONCLUSIONS

Elevated cPRA was associated with reduced rates of HT across all waitlist acuity tiers. Among HT waitlist candidates listed at the top acuity strata, the high cPRA category was associated with increased rates of delisting due to death or deterioration. Elevated cPRA may require consideration for critically ill candidates under continuous allocation.

The Association of the UNOS Heart Allocation Policy Change With Transplant and Left Ventricular Assist Device Access and Outcomes

In October 2018, the allocation policy for adult orthotopic heart transplant (OHTx) in the United States was changed, with the goal of reducing waitlist mortality and providing broader sharing of donor organs within the United States. This study aimed to assess the association of this policy change with changes in access to OHTx versus left ventricular assist devices (LVADs), overall and in key sociodemographic subgroups, in the United States from 2016 to 2019. We identified all patients receiving OHTx or LVAD between 2016 and 2019 using the National Inpatient Sample. Controlling for medical co-morbidities, prepolicy trends, and within-hospital-year effects, we fit a dynamic logistic regression model to evaluate patient and hospital factors associated with receiving OHTx versus LVAD before versus after policy change. We also examined the frequency of temporary mechanical circulatory support in the same fashion. We identified 2,264 patients who received OHTx and 3,157 who received LVADs during the study period. In its first year of implementation, the United Network for Organ Sharing policy change of 2018 was associated with no overall change utilization of OHTx versus LVAD. In OHTx recipients, the frequency of use of temporary mechanical circulatory support changed from 15.6% in the before period to 42.6% in the after period (p <0.001). Although the policy change was associated with differences in the odds of receiving an OHTx versus LVAD between different regions of the country, there were no significant changes based on age, gender, race/ethnicity, insurance status, or rurality. In conclusion, the United Network for Organ Sharing policy change on access to OHTx was associated with no overall change in OHTx versus LVAD use in its first year of implementation although we observed small changes in relative odds of transplant based on rurality. Shifts in regional allocation were not significant overall, although certain regions appeared to have a relative increase in their use of OHTx.

Use of exception status listing and related outcomes during two heart allocation policy periods

BACKGROUND

The October 2018 update to the heart allocation policy was intended to decrease exception status requests, whereby candidates are listed at a specific status due to perceived need despite not meeting prespecified criteria of illness severity. We assessed the use of exception status and waitlist outcomes before and after the 2018 policy.

METHODS

We used data from the Scientific Registry of Transplant Recipients on adult heart transplant candidates listed from 2015 to 2021. We assessed (1) the use of exception status across patient characteristics between the two periods and (2) transplant rate and waitlist mortality or delisting due to deterioration in each period. Patients listed by exception versus standard criteria were compared with multivariable logistic regression, and waitlist outcomes were assessed using Cox proportional hazard models with medical urgency and exception status as time-dependent covariates.

RESULTS

During the study period (n = 19,213), heart transplants under exception status increased postpolicy from 10.0% to 32.3%, with 20.6% of transplants performed for patients at status 2 exception. Exception status candidates postpolicy were more frequently Black or Hispanic/Latino and less likely to have hypertrophic or restrictive cardiomyopathy and had worse hemodynamics. Exception status listing was associated with higher transplant rates in both periods. Postpolicy, candidates listed status 1 exception had a lower likelihood for waitlist mortality or delisting (hazard ratio, 0.60; 95% CI, 0.37-0.99; and p = 0.05).

CONCLUSIONS

Under the 2018 policy, exception status listings dramatically increased. The policy change shifted the population of patients listed by exception status and affected waitlist mortality, which suggests a need to further evaluate the policy's impact.

Kidney health and function with left ventricular assist devices

PURPOSE OF REVIEW

Mechanical circulatory support (MCS) is a group of evolving therapies used for indications ranging from temporary support during a cardiac procedure to permanent treatment of advanced heart failure. MCS is primarily used to support left ventricle function, in which case the devices are termed left ventricular assist devices (LVADs). Kidney dysfunction is common in patients requiring these devices, yet the impact of MCS itself on kidney health in many settings remains uncertain.

RECENT FINDINGS

Kidney dysfunction can manifest in many different forms in patients requiring MCS. It can be because of preexisting systemic disorders, acute illness, procedural complications, device complications, and long-term LVAD support. After durable LVAD implantation, most persons have improvement in kidney function; however, individuals can have markedly different kidney outcomes, and novel phenotypes of kidney outcomes have been identified.

SUMMARY

MCS is a rapidly evolving field. Kidney health and function before, during, and after MCS is relevant to outcomes from an epidemiologic perspective, yet the pathophysiology underlying this is uncertain. Improved understanding of the relationship between MCS use and kidney health is important to improving patient outcomes.

Association of high-priority exceptions with waitlist mortality among heart transplant candidates

BACKGROUND

The US heart allocation system ranks candidates using six categorical status levels. Transplant programs can request exceptions to increase a candidate's status level if they believe their candidate has the same medical urgency as candidates who meet the standard criteria for that level. We aimed to determine if exception candidates have the same medical urgency as standard candidates.

METHODS

Using the Scientific Registry of Transplant Recipients, we constructed a longitudinal waitlist history dataset of adult heart-only transplant candidates listed between October 18, 2018 and December 1, 2021. We estimated the association between exceptions and waitlist mortality with a mixed-effects Cox proportional hazards model that treated status and exceptions as time-dependent covariates.

RESULTS

Out of 12,458 candidates listed during the study period, 2273 (18.2%) received an exception at listing and 1957 (15.7%) received an exception after listing. After controlling for status, exception candidates had approximately half the risk of waitlist mortality as standard candidates (hazard ratio [HR] 0.55, 95% confidence interval [CI] [0.41, 0.73], p < .001). Exceptions were associated with a 51% lower risk of waitlist mortality among Status 1 candidates (HR 0.49, 95% CI [0.27, 0.91], p = .023) and a 61% lower risk among Status 2 candidates (HR 0.39, 95% CI [0.24, 0.62], p < .001).

CONCLUSIONS

Under the new heart allocation policy, exception candidates had significantly lower waitlist mortality than standard candidates, including exceptions for the highest priority statuses. These results suggest that candidates with exceptions, on average, have a lower level of medical urgency than candidates who meet standard criteria.

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.

Sodium-Glucose Co-Transporter 2 Inhibitors in Heart Failure-Current Evidence in Special Populations

Sodium-glucose co-transporter 2 (SGLT2) inhibitors, originally used for diabetes mellitus, are gaining more popularity for other indications, owing to their positive cardiovascular and renal effects. SGLT2 inhibitors reduce heart failure (HF) hospitalization and improve cardiovascular outcomes in patients with type 2 diabetes. Later, SGLT2 inhibitors were evaluated in patients with HF with reduced ejection fraction (HFREF) and had beneficial effects independent of the presence of diabetes. Recently, reductions in cardiovascular outcomes were also observed in patients with HF with preserved ejection fraction (HFPEF). SGLT2 inhibitors also reduced renal outcomes in patients with chronic kidney disease. Overall, these drugs have an excellent safety profile with a negligible risk of genitourinary tract infections and ketoacidosis. In this review, we discuss the current data on SGLT2 inhibitors in special populations, including patients with acute myocardial infarction, acute HF, right ventricular (RV) failure, left ventricular assist device (LVAD), and type 1 diabetes. We also discuss the potential mechanisms behind the cardiovascular benefits of these medications.

The Year in Cardiothoracic Transplant Anesthesia: Selected Highlights From 2021 Part II: Cardiac Transplantation

This article spotlights the research highlights of this year that specifically pertain to the specialty of anesthesia for heart transplantation. This includes the research on recent developments in the selection and optimization of donors and recipients, including the use of donation after cardiorespiratory death and extended criteria donors, the use of mechanical circulatory support and nonmechanical circulatory support as bridges to transplantation, the effect of COVID-19 on heart transplantation candidates and recipients, and new advances in the perioperative management of these patients, including the use of echocardiography and postoperative outcomes, focusing on renal and cerebral outcomes.

Left ventricular assist device implantation and clinical outcomes in the Netherlands

BACKGROUND

Left ventricular assist device (LVAD) therapy is an established treatment for advanced heart failure with reduced ejection fraction. We evaluated the characteristics and clinical outcomes of patients implanted with an LVAD in the Netherlands.

METHODS

Patients implanted with an LVAD in the Netherlands between 2016 and 2020 were included in the analysis. Baseline characteristics entered into this registry, as well as clinical outcomes (death on device, heart transplantation) and major adverse events (device dysfunction, major bleeding, major infection and cerebrovascular event), were evaluated.

RESULTS

A total of 430 patients were implanted with an LVAD; mean age was 55 ± 13 years and 27% were female. The initial device strategy was bridge to transplant (BTT) in 50%, destination therapy (DT) in 29% and bridge to decision (BTD) in the remaining 21%. After a follow-up of 17 months, 97 (23%) patients had died during active LVAD support. Survival was 83% at 1 year, 76% at 2 years and 54% at 5 years. Patients implanted with an LVAD as a BTT had better outcomes compared with DT at all time points (1 year 86% vs 72%, 2 years 83% vs 59% and 5 years 58% vs 33%). Major adverse events were frequently observed, most often major infection, major bleeding and cerebrovascular events (0.84, 0.33 and 0.09 per patient-year at risk, respectively) and were similar across device strategies. Patients supported with HeartMate 3 had a lower incidence of major adverse events.

CONCLUSIONS

Long-term survival on durable LVAD support in the Netherlands is over 50% after 5 years. Major adverse events, especially infection and bleeding, are still frequently observed, but decreasing with the contemporary use of HeartMate 3 LVAD.

Practical application of the French two-score heart allocation scheme: Insights from a high-volume heart transplantation centre

BACKGROUND

In 2018, a cardiac allocation scheme based on an individual score considering the risk of death both on the waitlist and after heart transplantation was implemented in France.

AIMS

To analyse the practical application of the pre- and post-transplant risk score in a French high-volume heart transplantation centre.

METHODS

All consecutive adult patients listed for a first non-combined heart transplantation between 02 January 2018 and 30 June 2022 at our centre were included. Baseline characteristics of candidates and recipients were retrieved from the national CRISTAL registry. Both scores were calculated at listing and at transplant.

RESULTS

Overall, 364 patients were included. During follow-up, 257 patients (70.6%) were transplanted, and 57 (15.6%) died or were removed from the waitlist. Post-transplant 3-month survival was 84.8%. Total bilirubin and natriuretic peptides had the most important weight in the pretransplant risk score. This score had a major impact on waitlist outcomes: quartile 1 was characterized by low access to heart transplantation (58.2%) and risk of death on the waitlist (9.9%) compared with quartile 4 (heart transplantation rate 74.1%, mortality on the waiting list>20%). According to the post-transplant risk score, a minimal number of candidates were considered ineligible for heart transplantation (<1%), but 12.4% were contraindicated to at least one donor category. The number of contraindicated donor categories had a significant impact on waitlist outcomes. Although adequately calibrated, the post-transplant score had a limited discrimination (area under the curve 0.65, 95% confidence interval 0.59-0.71).

CONCLUSION

Our results highlight the major impact of pre- and post-transplantation risk scores on waitlist outcomes following the allocation scheme update.

Update on cardiogenic shock: from detection to team management

PURPOSE OF REVIEW

The following review is intended to provide a summary of contemporary cardiogenic shock (CS) profiling and diagnostic strategies, including biomarker and hemodynamic-based (invasive and noninvasive) monitoring, discuss clinical differences in presentation and trajectory between acute myocardial infarction (AMI)-CS and heart failure (HF)-CS, describe transitions to native heart recovery and heart replacement therapies with a focus on tailored management and emerging real-world data, and emphasize trends in team-based initiatives and interventions for cardiogenic shock including the integration of protocol-driven care.

RECENT FINDINGS

This document provides a broad overview of contemporary scientific consensus statements as well as data derived from randomized controlled clinical trials and observational registry working groups focused on cardiogenic shock management.

SUMMARY

This review highlights the increasingly important role of pulmonary artery catheterization in AMI-CS and HF-CS cardiogenic shock and advocates for routine application of algorithmic approaches with interdisciplinary care pathways. Cardiogenic shock algorithms facilitate the integration of clinical, hemodynamic, and imaging data to determine the most appropriate patient hemodynamic support platform to achieve adequate organ perfusion and decongestion.

Donation after circulatory determination of death in heart transplant: impact on current and future allocation policy

PURPOSE OF REVIEW

Historically, the selection criteria for heart transplant candidates has prioritized posttransplant survival while contemporary allocation policy is focused on improving waitlist survival. Donor scarcity has continued to be the major influence on transplant allocation policy. This review will address the opportunity of donation after circulatory determination of death (DCDD) and potential impact on future policy revisions.

RECENT FINDINGS

In 2018, changes to U.S. heart allocation policy led to several intended and unintended consequences. Beneficial changes include reduced waitlist mortality and broader geographic sharing. Additional impacts include scarcer pathways to transplant for patients with a durable left ventricular assist device, increased reliance on status exceptions, and expanded use of temporary mechanical support. DCDD is anticipated to increase national heart transplant volumes by ∼30% and will impact waitlist management. Centers that offer DCDD procurement will have reduced waitlist times, reduced waitlist mortality, and higher transplant volumes.

SUMMARY

While DCDD will provide more transplant opportunities, donor organ scarcity will persist and influence allocation policies. Differential patient selection, waitlist strategy, and outcome expectations may indicate that allocation is adjusted based on the procurement options at individual centers. Future policy, which will consider posttransplant outcomes, may reflect that different procurement strategies may yield different outcomes.

Impact of 2016 UNOS pediatric heart allocation policy changes on VAD utilization, waitlist, and post-transplant survival outcomes in children with CHD versus Non-CHD

AIMS

We analyzed the impact of the revised pediatric heart allocation policy on types of ventricular assist device (VAD) utilization, and waitlist (WL) and post-heart transplant (HT) survival outcomes in congenital heart disease (CHD) versus non-CHD patients before (Era-1) and after (Era-2) pediatric heart allocation policy implementation.

METHODS

We retrospectively reviewed the UNOS database from December 16, 2011, through March 31, 2021, for patients < 18 years old and listed for primary HT. We compared the differences observed between Era-1 and Era-2.

RESULTS

5551 patients were listed for HT, of whom 2447(44%) were in Era-1 and 3104(56%) were in Era-2. CHD patients were listed as status 1A unchanged, but the number of patients listed as status 1B decreased in Era-2, whereas the number of non-CHD patients listed as status 1A decreased, but status 1B increased. In Era-2 compared to Era-1, both temporary (1% to 4%, p < .001) and durable VAD (13.6% to 17.8%, p < .001) utilization increased, and the transplantation rate per 100-patient years increased in both groups. The median WL period for CHD patients increased marginally from 70 to 71 days (p = .06), whereas for non-CHD patients it decreased from 61 to 54 days (p < .001). Adjusted 90-day WL survival increased from 84% to 88%, p = .016 in CHD, but there was no significant change in non-CHD patients (p = .57). There was no significant difference in 1-year post-HT survival in CHD and non-CHD patients between Era-1 and Era-2.

CONCLUSIONS

In summary, after the revised heart allocation policy implementation, temporary and durable VAD support increased, HT rate increased, waitlist duration marginally increased in the CHD cohort and decreased in the non-CHD cohort, and 90-day WL survival probability improved in children with CHD without significant change in 1-year post-HT outcomes. Future studies are needed to identify changes to the policy that may further improve the listing criteria to improve WL duration and post-HT survival.

Impact of the 2018 French two-score allocation scheme on the profile of heart transplantation candidates and recipients: Insights from a high-volume centre

BACKGROUND

In 2018, a new cardiac allograft allocation scheme, based on an individual scoring system, considering the risk of death both on the waiting list and after heart transplantation, was implemented in France.

AIM

To assess the impact of this new scheme on the profile of transplantation candidates and recipients.

METHODS

In this single-centre retrospective study, we included consecutive patients listed and/or transplanted between 01 January 2012 and 30 September 2021 at La Pitié-Salpêtrière Hospital. Baseline characteristics of patients were retrieved from the national CRISTAL registry and were compared according to the type of allocation scheme (before or after 2018).

RESULTS

A total of 1098 newly listed transplantation candidates and 855 transplant recipients were included. One-year mortality rates after listing and after transplantation were 12.4% and 20%, respectively. At listing, the proportion of candidates on inotropes significantly declined following the scheme update (26.3 versus 20.9%; P=0.038), reflecting a change in medical practice. At transplantation, recipients had worse kidney function (estimated glomerular filtration rate<60mL/min/1.73 m²: old scheme, 29.7%; new scheme, 46.4%; P<0.001) and were more likely to be on extracorporeal membrane oxygenation support (33.5% versus 28.1%; P=0.080) under the new scheme, reflecting the prioritization of more severe patients. Outcomes after transplantation were not significantly influenced by the allocation system.

CONCLUSIONS

The implementation of the 2018 French allocation scheme had a limited impact on the profile of transplantation candidates, but selected more severe patients for transplantation without significant impact on outcomes after transplantation.

A national assessment of one-year heart outcomes after the 2018 adult heart allocation change

PURPOSE

On 10/18/2018 the Organ Procurement and Transplantation Network (OPTN) implemented modifications to adult heart allocation to better stratify the most medically urgent candidates by WL mortality. This paper reviews two years of post-policy monitoring with focus on post-transplant outcomes, especially for recipients with MCSDs.

METHODS

Cohorts of WL additions and recipients pre (10/18/16-10/17/18) and post (10/18/18-10/17/20) policy implementation were compared using the OPTN database. Competing risks analyses of waitlist mortality and Kaplan-Meier one-year post-transplant survival were performed by medical urgency statuses and policy era. Similar analyses were performed for subsets of candidates and recipients on devices.

RESULTS

Pre-implementation status 1A candidates had the highest cumulative incidence of removal from the waitlist due to death or too sick to transplant and the highest cumulative incidence of transplant, followed by statuses 1B and 2. Median time to transplant decreased from 226 to 85 days for those transplanted. There was no difference in one-year patient survival (pre=91.3% [90.2, 92.4]; post=91.8% [90.8, 92.9]; p=0.44) overall, or for recipients transplanted with an LVAD (pre=91.7% [90.1, 93.2]; post=91.4% [89.7, 93.2]; p=0.85) or IABP (pre=91.7% [88.1, 95.4]; post=92.1% [90.1, 94.0]; p=0.92).

CONCLUSION

The policy improved stratification of the most medically urgent candidates according to risk of death on the WL with decreased median wait times, higher transplant rates and no observed adverse effect on 1-year patient survival. No adverse effects for candidates listed or transplanted on IABP, ECMO, or LVAD were observed.

The Society of Thoracic Surgeons Intermacs 2022 Annual Report: Focus on the 2018 Heart Transplant Allocation System

The 13th annual report from The Society of Thoracic Surgeons (STS) Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs) highlights outcomes for 27,314 patients receiving continuous-flow durable left ventricular assist devices (LVAD) during the last decade (2012-2021). In 2021, 2464 primary LVADs were implanted, representing a 23.5% reduction in the annual volume compared with peak implantation in 2019 and an ongoing trend from the prior year. This decline is likely a reflection of the untoward effects of the coronavirus disease 2019 pandemic and the change in the United States heart transplant allocation system in 2018. The last several years have been characterized by a shift in device indication and type, with 81.1% of patients now implanted as destination therapy and 92.7% receiving an LVAD with full magnetic levitation in 2021. However, despite an older, more ill population being increasingly supported preimplant with temporary circulatory devices in the recent (2017-2021) vs prior (2012-2016) eras, the 1- and 5-year survival continues to improve, at 83.0% and 51.9%, respectively. The adverse events profile has also improved, with a significant reduction in stroke, gastrointestinal bleeding, and hospital readmissions. Finally, we examined the impact of the change in the heart transplant allocation system in 2018 on LVAD candidacy, implant strategy, and outcomes. In the competing-outcomes analysis, the proportion of transplant-eligible patients receiving a transplant has declined from 56.5% to 46.0% at 3 years, whereas the proportion remaining alive with ongoing support has improved from 24.1% to 38.1% at 3 years, underscoring the durability of the currently available technology.

Bridging to transplant with HeartMate 3 left ventricular assist devices in the new heart organ allocation system: An individualized approach

BACKGROUND

Following the MOMENTUM 3 trial and the discontinuation of the HeartWare HVAD, the HeartMate 3 LVAD (HM 3) has become the main durable device for bridging to transplantation; however, outcome of this strategy in the new heart allocation system is not well understood.

METHODS

The United Network for Organ Sharing (UNOS) registry was queried to include adult patients (≥18 years old) listed for heart transplantation between 2010 and 2020. Trends in durable LVAD utilization and outcomes of patients with HM 3 LVAD were examined in the pre- vs post-heart allocation system.

RESULTS

From 2017 to 2020, there was a 28.3% decline in the number of patients waitlisted with an FDA-approved durable LVAD. Overall, 449 patients were waitlisted with HM 3 in the pre-allocation era compared to 1094 patients in the post-allocation. Cumulative incidence of heart transplantation (53.4% vs 50.7%, p = 0.76) and death or delisting for worsening status (5.0%, vs 4.2%, p = 0.43) at 1-year after listing with HM 3 LVAD was comparable in the pre- vs post-allocation era. Old age (>50), ischemic HF, poor functional status, elevated creatinine (>1.3 mg/dL), pulmonary hypertension (>3 WU), and obesity (body mass index > 33 kg/m²) were predictors of post-transplant graft mortality after bridging with HM 3.

CONCLUSIONS

While the utilization of durable devices as BTT have declined under the new heart allocation system, bridging with HM 3 LVAD remains a safe strategy in carefully selected patients. Bridging decision should be individualized based on patient risk factors.