Risk Factors and Prognosis of Patients With Primary Graft Failure After Heart Transplantation: An Asian Center Experience

Improvements in Extracorporeal Membrane Oxygenation for Primary Graft Failure After Heart Transplant

BACKGROUND

Severe primary graft failure is a life-threatening complication of heart transplantation that may require venoarterial extracorporeal membrane oxygenation (VA-ECMO) support. Surgical practices and management strategies regarding VA-ECMO vary between and within centers.

METHODS

We performed a single-center retrospective cohort study on adult patients who received VA-ECMO for primary graft failure between 2013 and 2020. Clinical data were obtained from chart review and national databases. Patients were stratified by transplantation before or after 2017, when our center adopted additional objective criteria for VA-ECMO, adopted partial-flow support, and changed from central cannulation to chimney graft arterial cannulation of brachiocephalic, axillary, or aorta. The primary outcome was survival to device weaning. Secondary outcomes were survival to discharge, survival to 1 year, complications on support, and time to sedation weaning and extubation.

RESULTS

From 276 heart transplant recipients, 39 severe primary graft failure patients requiring VA-ECMO were identified. Incidence of graft failure was 13% (n = 18 of 135) pre-2017 and 15% (n = 21 of 141) post-2017. Survival at all time points improved significantly after 2017, with greatest difference in survival to device weaning (61% pre-2017 vs 100% post-2017). After controlling for other factors in multivariable Cox regression modeling, transplantation after 2017 was a predictor of reduced mortality (hazard ratio, 0.209; 95% CI, 0.06-0.71; P = .01). Significant differences were not observed in other secondary outcomes of recovery.

CONCLUSIONS

The new VA-ECMO strategy displayed reasonable survival and a remarkable improvement from the prior system.

Increased severe primary graft dysfunction in left ventricular assist device patients following united network for organ sharing allocation changes

INTRODUCTION

In 2018, the United Network for Organ Sharing (UNOS) implemented a new heart allocation system which prioritized patients on temporary support devices and left-ventricular assist device (LVAD) patients with complications. These changes have the potential to impact outcomes for patients bridged to transplant with an LVAD.

METHODS

We performed a retrospective study of 168 adult heart transplant recipients at our center between 2016 and 2020 evaluating post-transplant outcomes before and after UNOS allocation changes. Donor and recipient data were retrieved from chart review and national databases. The primary outcome of this study was severe primary graft dysfunction (PGD) with secondary outcomes of 30-day readmission, 30-day mortality, and 1-year mortality.

RESULTS

Incidence of severe PGD was similar in the overall cohort before and after the changes (10% vs. 15%, respectively, p = .3) and increased in the LVAD-bridged cohort (12% vs. 40%, respectively, p < .01). Secondary outcomes of readmission and survival were similar between all groups. Blood transfusion was predictive of severe PGD in multivariable modeling (OR 1.3 [1.11-1.59], p < .01).

Life impact of VA-ECMO due to primary graft dysfunction in patients after orthotopic heart transplantation

AIMS

Primary graft dysfunction (PGD) is a feared complication after heart transplantation (HTX). HTX patients frequently receive veno-arterial extracorporeal membrane oxygenation (VA-ECMO) until graft recovery. Long-term mortality of patients weaned from VA-ECMO after HTX is comparable with non-ECMO patients. However, impact on quality of life is unknown. This study investigated days alive and out of hospital (DAOH) as patient-centred outcome in HTX patients at 1 year after surgery.

METHODS AND RESULTS

This retrospective single-centre cohort study included patients who underwent HTX at the University Hospital Düsseldorf, Germany, from 2010 to 2020. Main exposure was VA-ECMO due to PGD. VA-ECMO and non-VA-ECMO patients were compared regarding the primary endpoint DAOH at 1 year after HTX. Subgroup analysis for patients weaned from VA-ECMO was performed. In total, 144 patients were included into analysis; 1 year mortality was significantly lower in non-ECMO patients [non-ECMO 14.3% (14/98) vs. VA-ECMO 34.8% (16/46), adjusted hazard ratio: 0.32, 95% confidence interval: 0.15-0.74; P = 0.002]. Mortality did not differ significantly between patients weaned from VA-ECMO and non-ECMO patients [non-ECMO 14.3% (14/98) vs. VA-ECMO (weaned) 18.9% (7/37), adjusted hazard ratio: 0.72, 95% confidence interval: 0.27-1.90; P = 0.48]. DAOH were significantly higher in non-ECMO patients compared with VA-ECMO patients and patients weaned from VA-ECMO [non-ECMO vs. VA-ECMO: median 310 (inter-quartile range 277-327) days vs. 243 (0-288) days; P < 0.0001; non-ECMO vs. VA-ECMO (weaned): 310 (277-327) days vs. 253 (208-299) days; P < 0.0001]. These results were still significant after multivariable adjustment with forced entry of predefined covariables.

CONCLUSIONS

Despite similar survival rates, VA-ECMO due to PGD has a relevant life impact as defined by DAOH in the first year after HTX. As a more patient-centred endpoint, DAOH may contribute to a more comprehensive assessment of outcome in HTX patients.

Donor Left Ventricular Function Assessed by Echocardiographic Strain is a Novel Predictor of Primary Graft Failure After Orthotopic Heart Transplantation

OBJECTIVES

This study sought to determine the utility of donor left ventricular function assessment by echocardiographic left ventricular global longitudinal strain (LV GLS) in predicting primary graft failure (PGF) after orthotopic heart transplantation (HT).

DESIGN

Retrospective, observational study.

SETTING

Tertiary referral hospital.

PARTICIPANTS

Adult patients (>18 years) who underwent isolated HT.

INTERVENTIONS

Demographic, clinical, and echocardiographic data were collected on 100 patients who underwent HT between January 2010 and December 2019 at the authors' institution. The respective donor variables, as well as procedural factors, were reviewed and analyzed to assess their independent association with PGF. Standard donor echocardiographic measurements were supplemented by two-dimensional speckle-tracking echocardiography to obtain LV GLS. PGF was defined as per the International Society for Heart and Lung Transplantation 2014 consensus statement.

MEASUREMENTS AND MAIN RESULTS

PGF occurred in 40 of the 100 patients (40%). Initial univariate analysis found that RADIAL score, donor ejection fraction, and donor LV GLS were associated with PGF. However, in a multivariate Cox regression analysis, only RADIAL score and donor LV GLS remained significant predictors of PGF, with a p < 0.001. By receiver operating characteristic curve analysis, LV GLS at a cut-off value of -11.5% showed the greatest area under the curve (area under the curve = 0.889; 95% confidence interval, 0.826-0.952) and predicted PGF with 92.5% sensitivity and 65% specificity.

CONCLUSIONS

Impaired donor LV GLS was proven to be an independent predictor of PGF after HT.

Amiodarone Use Prior to Cardiac Transplant Impacts Early Post-Transplant Survival

PURPOSE

It remains unclear if use of amiodarone pre-cardiac transplantation impacts early post-transplant survival.

METHODS

We selected all patients undergoing heart transplant from 2004 to 2006 with available information using the United Network for Organ Sharing database (n = 4057). Multivariable Cox models compared the risk of death within 30 days post-transplant in patients who were taking amiodarone at the time of transplant listing (n = 1227) to those who were not (n = 2830).

RESULTS

Mean age was 52 (± 12) years, and 23% were women. Patients who died within 30 days (n = 168) were older; had higher panel reactive antibody levels, higher bilirubin levels, and higher prevalence of prior cardiac surgery; were often at status 1B; and had higher use of amiodarone at listing compared to those who survived (5.3% versus 3.6%; p = 0.02). Cause of death was unknown in 49% and was reported as graft failure in 43% of cases. In multivariable Cox models, patients on amiodarone at the time of listing had 1.56-fold higher risk of post-transplant death within 30 days (95% confidence intervals 1.08-2.27) compared to patients who were not on amiodarone at listing (C-statistic 0.70).

CONCLUSION

In conclusion, patients who reported taking amiodarone at the time of listing for transplant had a higher risk of death within 30 days post-transplant.

Review of interactions between high-risk pediatric heart transplant recipients and marginal donors including utilization of risk score models

BACKGROUND

Donor organ acceptance practices vary among pediatric heart transplant professionals. We sought to understand what is known about the interactions between the "high-risk" recipient and the "marginal donor," and how donor risk scores can impact this discussion.

METHODS

A systematic review of published literature on pediatric HTx was undertaken with the assistance of a medical librarian. Two authors independently assessed search results, and papers were reviewed for inclusion.

RESULTS

We found that there are a large number of individual factors, and clusters of factors, that have been used to label individual recipients "high-risk" and individual donors "marginal." The terms "high-risk recipient" and "marginal donor" have been used broadly in the literature making it virtually impossible to make comparisons between publications. In general, the data support that patients who could be easily agreed to be "sicker recipients" are at more risk compared to those who are clearly "healthier," albeit still "sick enough" to need transplantation. Given this variability in the literature, we were unable to define how being a "high-risk" recipient interplays with accepting a "marginal donor." Existing risk scores are described, but none were felt to adequately predict outcomes from factors available at the time of offer acceptance.

CONCLUSIONS

We could not determine what makes a donor "marginal," a recipient "high-risk," or how these factors interplay within the specific recipient-donor pair to determine outcomes. Until there are better risk scores predicting outcomes at the time of organ acceptance, programs should continue to evaluate each organ and recipient individually.

Management of primary graft failure after heart transplantation: Preoperative risks, perioperative events, and postoperative decisions

Primary graft failure (PGF) after heart transplantation (HT) is a devastating and unexpected event characterized by failure of the graft to adequately support recipient circulation necessitating high doses of vasopressors and inotropes and/or temporary mechanical circulatory support. Although it represents an increasingly common event in the current era, there remains a high degree of variability in prevalence, reported risk factors, and approach to this clinical entity. The purpose of the current review is to highlight preoperative considerations including known incidence and risk factors, perioperative issues involving the identification and management of PGF, and postoperative decisions related to weaning of mechanical circulatory support and titration of immunosuppressive therapy. Lastly, we highlight future directions in PGF research, involving basic and translational research, that have the potential to uncover novel strategies of risk stratification and treatment. CASE: Our patient is a 53-year-old man with end-stage non-ischemic dilated cardiomyopathy complicated by ventricular tachycardia (VT), post-capillary pulmonary hypertension, and renal insufficiency. After progressing to NYHA Class IV symptoms, he underwent implantation of a durable left ventricular assist device (LVAD) as bridge to transplant (BTT). On device support, he developed recurrent VT resulting in multiple defibrillator discharges and hospital admission for intravenous anti-arrhythmic therapy. He is subsequently upgraded to a higher status on the waiting list. A suitable donor is identified, with an appropriate predicted heart mass and an anticipated ischemic time of <4 hours. He is taken to the operating room, where at the time of anesthesia induction he develops vasodilatory shock, requiring high-dose vasopressors, and cardiopulmonary bypass (CPB) support for dissection. After surgical anastomosis, cross clamp removal and reperfusion, graft function is extremely poor, there is significant bradycardia requiring pacing, and the patient is unable to be weaned successfully from CPB. Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is initiated, and the patient is transferred to the intensive care unit. Retrospective flow crossmatch is negative. This patient is suffering from severe primary graft failure.

Extracorporeal membrane oxygenation as treatment of graft failure after heart transplantation

Heart transplantation (HTx) is a valuable option in eligible patients with end-stage heart failure. The most significant complication in the immediate post-operative period is early graft failure (EGF), with a mean incidence of 20-25%. EGF is a major risk factor for death and accounts for 40-50% of early mortality after HTx. Despite the use of inotropes, EGF may persist and require temporary mechanical circulatory support. Extracorporeal membrane oxygenation (ECMO) has been investigated over the years and has proved to be a reliable strategy in patients with EGF after HTx. This study aims to review the contemporary literature on this topic. Considering short-term outcomes, 45-80% of patients were discharged alive from hospital. Duration of support is variable, with a mean duration of 4-8 days. Cannulation strategy and device selection have no differences with respect to short-term outcomes. The main causes of death are multi-organ failure, bleeding, heart failure, stroke and sepsis. Considering long-term outcomes, ECMO survivors appear to have similar survival rates to HTx patients who did not experience EGF. Also, ECMO-treated EGF, among survivors, has no detrimental effect for graft function. In conclusion, ECMO is a reliable therapeutic option to support patients with severe graft failure after HTx, providing adequate support with either central or peripheral arteriovenous cannulation. Further studies will be needed to establish the correct threshold for ECMO support and to provide long-term results.

Linagliptin improved myocardial function recovery in rat hearts after a prolonged hypothermic preservation

AIMS

To determine whether linagliptin, a dipeptidyl peptidase 4 inhibitor, can promote the recovery of cardiac function after hypothermic preservation.

MAIN METHODS

Rat hearts were preserved in cold Celsior solution with or without linagliptin for 9 h. Cardiac function was evaluated at 60 min of reperfusion after hypothermic preservation. Cardiac mitochondrial morphology was observed using transmission electron microscope. The expression of dynamin-related protein 1 (Drp1), NADPH oxidase 2 (NOX2), calmodulin-dependent protein kinase II (CaMKII) were detected using Western blot.

KEY FINDINGS

Compared with Celsior group, supplement of Celsior solution with linagliptin (0.25-0.75 nM) could significantly prevent hypothermic preservation-induced cardiac dysfunction. The expression of NOX2 protein, ROS level and MDA content in cardium were increased after hypothermic preservation, which was inhibited by linagliptin. Although the mitofusin1, 2, optic atrophy type 1, and total Drp1 expression in myocardium did not change, the level of p-Drp1 S616 and mitochondrial Drp1 were enhanced after hypothermic preservation. Linagliptin supplement could inhibit the hypothermic preservation-induced increase in p-Drp1 S616 and mitochondrial Drp1 protein, and mitigate the mitochondrial fragmentation. Level of p-CaMKII protein enhanced after hypothermic preservation, which could be prevented by linagliptin or a NOX2 inhibitor Phox-I2. Both Phox-I2 and a CaMKII inhibitor KN-93 could reduce the hypothermic preservation-induced increase in p-Drp1 S616 and mitochondrial Drp1 protein.

SIGNIFICANCE

Supplement Celsior solution with linagliptin could improve cardiac function recovery in 9-h hypothermic preserved rat hearts. The cardioprotective effect of linagliptin might be due to the inhibition of Drp1 phosphorylation and mitochondrial translocation by preventing NOX2-mediated CaMKII activation.

Postoperative management of heart transplantation patients

Heart transplant recipients are at risk for a number of post-transplantation complications such as graft dysfunction, rejection, and infection. The rates of many complications are decreasing over time, and prognosis is improving. However, these patients continue to experience significant morbidity and mortality. This review focuses on the optimal management of heart transplant recipients in the postoperative period, based on current knowledge. More information is needed about the best ways to predict, prevent, and treat primary graft dysfunction, right ventricular failure, and cellular and antibody-mediated rejection.

Heart Transplant in Asia

The prevalence of heart failure has increased in Asia. A significant proportion of patients with heart failure and left ventricular dysfunction end up with advanced heart failure or end-stage heart disease. These patients may be placed on the waiting list for heart transplant. There are more than 10 countries in Asia that have an active heart transplant program. The number of heart transplants performed is limited despite an increase in the number of patients with end-stage heart failure mainly because of donor shortage, which may be related to religious belief and inefficient allocation policy.

Hypothermic continuous machine perfusion improves metabolic preservation and functional recovery in heart grafts

The number of heart transplants is decreasing due to organ shortage, yet the donor pool could be enlarged by improving graft preservation. Hypothermic machine perfusion (MP) has been shown to improve kidney, liver, or lung graft preservation. Sixteen pig hearts were recovered following cardioplegia and randomized to two different groups of 4-hour preservation using either static cold storage (CS) or MP (Modified LifePort© System, Organ Recovery Systems, Itasca, Il). The grafts then underwent reperfusion on a Langendorff for 60 min. Energetic metabolism was quantified at baseline, postpreservation, and postreperfusion by measuring lactate and high-energy phosphates. The contractility index (CI) was assessed both in vivo prior to cardioplegia and during reperfusion. Following reperfusion, the hearts preserved using CS exhibited higher lactate levels (56.63 ± 23.57 vs. 11.25 ± 3.92 μmol/g; P < 0.001), increased adenosine monophosphate/adenosine triphosphate (AMP/ATP) ratio (0.4 ± 0.23 vs. 0.04 ± 0.04; P < 0.001), and lower phosphocreatine/creatine (PCr/Cr) ratio (33.5 ± 12.6 vs. 55.3 ± 5.8; P <0.001). Coronary flow was similar in both groups during reperfusion (107 ± 9 vs. 125 + /-9 ml/100 g/min heart; P = ns). CI decreased in the CS group, yet being well-preserved in the MP group. Compared with CS, MP resulted in improved preservation of the energy state and more successful functional recovery of heart graft.