Donor B-type natriuretic peptide predicts early cardiac performance after heart transplantation

Donor heart selection: Evidence-based guidelines for providers

The proposed donor heart selection guidelines provide evidence-based and expert-consensus recommendations for the selection of donor hearts following brain death. These recommendations were compiled by an international panel of experts based on an extensive literature review.

Plasma Levels of SERCA2a as a Noninvasive Biomarker of Primary Graft Dysfunction After Heart Transplantation

BACKGROUND

Noninvasive detection of primary graft dysfunction (PGD) remains a major challenge. SERCA2a plays an important role in cardiac homeostasis and its dysregulation has been associated with ventricular dysfunction and rejection. This study aimed to determine the potential utility of plasma levels of SERCA2a as a biomarker of PGD.

METHODS

One hundred thirty-five plasma samples were collected from adult recipients 2-6 hours before heart transplantation (HT). Plasma concentrations of SERCA2a were determined using a specific sandwich ELISA. Variables related to the recipient, the donor, and the periprocedural were collected to determine a multivariate predictive model of PGD.

RESULTS

Levels of SERCA2a were decreased in patients who developed PGD (median 0.430 ng/mL [interquartile range, 0.260-0.945] versus 0.830 ng/mL [interquartile range, 0.582-1.052]; P = 0.001). Receiver operating characteristic curve analysis revealed that SERCA2a discriminated between patients with and without PGD (AUC = 0.682; P = 0.001), and a cutoff point ≥ 0.60 ng/mL was a protective independent predictor of PGD (odds ratio 0.215 [P = 0.004]). Three independent predictors of PGD in this study were reduced levels of pre-HT SERCA2a, increased bilirubin levels, and short-term mechanical circulatory support bridge to transplantation. The analysis of the receiver operating characteristic curve of the model obtained a significant AUC 0.788, P = 0.0001.

CONCLUSIONS

Our findings suggest that assessment of SERCA2a plasma levels may improve risk prediction for the occurrence of PGD and could be considered as a novel noninvasive biomarker in patients undergoing HT.

Suppression of tumorigenicity-2 (ST2) is a promising biomarker in heart transplantation

BACKGROUND

To evaluate the association between donors' and recipients' serum levels of soluble ST2 (sST2) and recipients' outcome after heart transplantation (HT).

METHODS

Blood samples were collected in 50 heart donors before organ procurement and in 50 recipients before HT (D0), a week after HT (D7) and at every first year's endomyocardial biopsy (EMB); sST2 levels were evaluated by ELISA.

RESULTS

Donors who sustained a cardiac arrest, had significantly higher sST2 levels. Recipients on national high emergency waiting list had significantly higher preoperative sST2 levels compared to recipients who did not. Recipients with postoperative sepsis or continuous renal replacement therapy had significantly higher sST2 levels at D7. Recipients who needed a postoperative ECMO for allograft dysfunction had significantly higher sST2 levels in their corresponding donors. Recipients who died during the hospitalization after the transplantation had significantly higher sST2 levels at D7 compared to recipients who did not. No difference was observed in sST2 levels in recipients who had mild allograft rejection and recipient who did not.

CONCLUSIONS

Higher sST2 levels in donors are associated to allograft dysfunction requiring ECMO in recipients; higher postoperative sST2 levels in recipients are associated with in-hospital mortality.

Evaluation of donor heart for transplantation

Cardiac transplantation is considered the gold-standard treatment option for patients suffering from end-stage heart failure refractory to maximum medical therapy. A major determinant of graft function and recipient survival is a comprehensive evaluation of the donor allograft. Challenges arise when designing and implementing an evidence-based donor evaluation protocol due to the number of influential donor-specific characteristics and the complex interactions that occur between them. Here, we present our systematic approach to donor evaluation by examining the impact that relevant donor variables have on graft function and recipient outcomes.

Donor Cardiac Troponin for Prognosis of Adverse Outcomes in Cardiac Transplantation Recipients: a Systematic Review and Meta-analysis

BACKGROUND

Cardiac troponin is a highly specific and widely available marker of myocardial injury, and elevations in cardiac transplant donors may influence donor selection. We aimed to investigate whether elevated donor troponin has a role as a prognostic biomarker in cardiac transplantation.

METHODS

In a systematic review and meta-analysis, we searched MEDLINE, Embase, and the Cochrane Library, without language restriction, from inception to December 2020. We included studies reporting the association of elevated donor troponin with recipient outcome after cardiac transplant. We generated summary odds ratios and hazard ratios for the association of elevated donor troponin with short- and long-term adverse outcomes. Methodological quality was monitored using the Quality In Prognosis Studies tool, and interstudy heterogeneity was assessed using a series of sensitivity and subgroup analyses.

RESULTS

We included 17 studies involving 15 443 patients undergoing cardiac transplantation. Elevated donor troponin was associated with increased odds of graft rejection at 1 y (odds ratio, 2.54; 95% confidence interval, 1.22-5.28). No significant prognostic relationship was found between donor troponin and primary graft failure, short- to long-term mortality, cardiac allograft vasculopathy, and pediatric graft loss.

CONCLUSIONS

Elevated donor troponin is not associated with an increased short- or long-term mortality postcardiac transplant despite increasing the risk of graft rejection at 1 y. Accordingly, an elevated donor troponin in isolation should not exclude donation.

Primary Graft Dysfunction after Heart Transplantation - Unravelling the Enigma

Primary graft dysfunction (PGD) remains the main cause of early mortality following heart transplantation despite several advances in donor preservation techniques and therapeutic strategies for PGD. With that aim of establishing the aetiopathogenesis of PGD and the preferred management strategies, the new consensus definition has paved the way for multiple contemporaneous studies to be undertaken and accurately compared. This review aims to provide a broad-based understanding of the pathophysiology, clinical presentation and management of PGD.

Strategies for hemodynamic maintenance of potential brain-dead donor: integrative review

OBJECTIVE

To learn about the scientific production on strategies adopted for hemodynamic maintenance of brain-dead patients.

METHODS

Integrative review with articles published between 2007 and 2019, in Scientific Electronic Library Online (SciELO), Latin American and Caribbean Health Sciences Literature (LILACS), PubMed® and ScienceDirect. The descriptors " Hemodinâmica AND Morte Encefálica " and "Hemodynamics AND Brain Death" were used. Exclusion criteria were non-human research and gray literature.

RESULTS

A total of 21 articles were listed. As strategies, the use of drugs - noradrenaline (n=8), vasopressin (n=7), dobutamine (n=6), hydrocortisone (n=4) and methylprednisolone (n=4); invasive (n=10) and noninvasive (n=13) cardiac monitoring; control of ventilatory parameters (n=12); and correction of fluid and electrolyte disturbances (n=17) were highlighted.

CONCLUSION

The main strategies found in this integrative review were regulation of blood pressure and temperature, use of catecholamines and corticosteroids, in addition to the need for an early diagnosis of brain death. However, the lack of clearer protocols on the subject is notorious, making management with the potential donor difficult.

New Approaches to Donor Selection and Preparation in Heart Transplantation

Purpose of review

With increasing survival of patients with stage D heart failure, the demand for heart transplantation has increased. The supply of donor hearts remains relatively limited. Strategies have been investigated and new technologies have been developed to expand the current donor pool. These new approaches will be discussed herein.

Recent findings

Donor hearts are often considered “marginal” due to risk factors such as older age, size mismatch with the intended recipient, prolonged ischemic time, presence of left ventricular hypertrophy, and hepatitis B/C infection. We reviewed recent data regarding the use of donor hearts with these risk factors and suggest ways to safely liberalize current donor heart acceptance criteria. New technologies such as temperature-controlled transport systems and ex vivo cardiac perfusion methods have also demonstrated promising short-term and intermediate outcomes as compared with routine cold storage, by promoting heart preservation and enabling heart procurement from remote sites with shorter cold ischemic time. Recent use of hearts from donation after circulatory death donors has demonstrated comparable outcomes to conventional donation after brain death, which can further expand the current donor pool.

Summary

Careful selection of “marginal” donor hearts, use of ex vivo cardiac perfusion, and acceptance of hearts after circulatory death may expand our current cardiac donor pool with comparable outcomes to conventional donor selection and preparation methods.

C-Reactive protein level and left ventricular mass are associated with acute cellular rejection after heart transplant

OBJECTIVES

Acute cellular rejection (ACR) remains a major complication of heart transplant (HT). The gold standard for its diagnosis is endomyocardial biopsy (EMB), whereas the role of non-invasive biomarkers for detecting ACR is unclear. This study aimed to identify non-invasive biomarkers for the diagnosis of ACR in patients undergoing HT and presenting with normal left ventricular function.

METHODS

We evaluated patients who underwent HT at a single center between January 2010 and June 2019. Patients were enrolled after HT, and those with left ventricular (LV) systolic dysfunction before EMB were excluded. We included only the results of the first EMB performed at least 30 days after HT (median, 90 days). Troponin, B-type natriuretic peptide (BNP), and C-reactive protein (CRP) levels were measured and echocardiography was performed up to 7 days before EMB. ACR was defined as International Society for Heart and Lung Transplantation grade 2R or 3R on EMB. We performed logistic regression analysis to identify the non-invasive predictors of ACR (2R or 3R) and evaluated the accuracy of each using area under the receiver operator characteristic curve analysis.

RESULTS

We analyzed 72 patients after HT (51.31±13.63 years; 25 [34.7%] women); of them, 9 (12.5%) developed ACR. Based on multivariate logistic regression analysis, we performed forward stepwise selection (entry criteria, p<0.05). The only independent predictors that remained in the model were CRP level and LV mass index. The optimal cut-off point for CRP level was ≥15.9 mg/L (odds ratio [OR], 11.7; p=0.007) and that for LV mass index was ≥111 g/m2 (OR, 13.6; p=0.003). The area under the receiver operating characteristic curve derived from this model was 0.87 (95% confidence interval [CI], 0.75-0.99), with sensitivity of 85.7% (95% CI, 42.1%-99.6%), specificity of 78.4% (95% CI, 64.7%-88.7%), positive predictive value of 35.3% (95% CI, 14.3%-61.7%), and negative predictive value of 97.6% (95% CI, 87.1%-99.9%).

CONCLUSIONS

Among patients undergoing HT, CRP level and LV mass were directly associated with ACR, but troponin and BNP levels were not.

Effects of donor cause of death, ischemia time, inotrope exposure, troponin values, cardiopulmonary resuscitation, electrocardiographic and echocardiographic data on recipient outcomes: A review of the literature

BACKGROUND

Heart transplantation has become standard of care for pediatric patients with either end-stage heart failure or inoperable congenital heart defects. Despite increasing surgical complexity and overall volume, however, annual transplant rates remain largely unchanged. Data demonstrating pediatric donor heart refusal rates of 50% suggest optimizing donor utilization is critical. This review evaluated the impact of donor characteristics surrounding the time of death on pediatric heart transplant recipient outcomes.

METHODS

An extensive literature review was performed to identify articles focused on donor characteristics surrounding the time of death and their impact on pediatric heart transplant recipient outcomes.

RESULTS

Potential pediatric heart transplant recipient institutions commonly receive data from seven different donor death-related categories with which to determine organ acceptance: cause of death, need for CPR, serum troponin, inotrope exposure, projected donor ischemia time, electrocardiographic, and echocardiographic results. Although DITs up to 8 hours have been reported with comparable recipient outcomes, most data support minimizing this period to <4 hours. CVA as a cause of death may be associated with decreased recipient survival but is rare in the pediatric population. Otherwise, however, in the setting of an acceptable donor heart with a normal echocardiogram, none of the other data categories surrounding donor death negatively impact pediatric heart transplant recipient survival.

CONCLUSIONS

Echocardiographic evaluation is the most important donor clinical information following declaration of brain death provided to potential recipient institutions. Considering its relative importance, every effort should be made to allow direct image visualization.

ISHLT consensus statement on donor organ acceptability and management in pediatric heart transplantation

The number of potential pediatric heart transplant recipients continues to exceed the number of donors, and consequently the waitlist mortality remains significant. Despite this, around 40% of all donated organs are not used and are discarded. This document (62 authors from 53 institutions in 17 countries) evaluates factors responsible for discarding donor hearts and makes recommendations regarding donor heart acceptance. The aim of this statement is to ensure that no usable donor heart is discarded, waitlist mortality is reduced, and post-transplant survival is not adversely impacted.

Primary graft dysfunction after heart transplantation: a thorn amongst the roses

Primary graft dysfunction (PGD) remains the leading cause of early mortality post-heart transplantation. Despite improvements in mechanical circulatory support and critical care measures, the rate of PGD remains significant. A recent consensus statement by the International Society of Heart and Lung Transplantation (ISHLT) has formulated a definition for PGD. Five years on, we look at current concepts and future directions of PGD in the current era of transplantation.

Biomarkers and Donor Selection in Heart Transplantation

BACKGROUND

Previously, we showed that B-type natriuretic peptide (BNP) measured in the donor was related to cardiac performance after cardiac transplantation. The present study assesses the value of 3 biomarkers in the selection of donor hearts in a larger cohort.

METHODS

Blood samples were prospectively obtained in 105 brain-dead patients scheduled for heart donation. BNP, soluble suppressor of tumorigenicity 2 (ST2), and troponin of heart donors were correlated with hemodynamic parameters early after transplantation as well as with the mortality of the recipients.

RESULTS

A significant inverse relationship was found between donor BNP measured at the time of donation and recipient cardiac index and cardiac output at day 13 post-transplantation (r = -0.31, P = .005, and r = -0.34, P = .0016, respectively). Logistic regression analysis-including BNP, ST2, and troponin-showed that donor BNP was a predictor of a poor cardiac index (< 2.2 L/min/m²) in the recipient (P = .04). A donor BNP > 132 pg/mL has a sensitivity of 56% (95% confidence interval 21-86) and a specificity of 86% (95% confidence interval 77-93) to predict poor cardiac performance in the recipient. When the donor BNP is ≤ 132 pg/mL, the risk of a poor cardiac function in the recipient is very low (negative predictive value 94%). Mortality at 30 days was also correlated to donor BNP (r = 0.29, P = .0029). Long-term survival of the recipient was not correlated to the biomarkers measured in the donor.

CONCLUSION

Donor BNP, but not donor ST2 or high-sensitivity troponin, provides information on the donor heart and early post-transplant performance, including 1-month mortality.

Assessment of potential heart donors: A statement from the French heart transplant community

Assessment of potential donors is an essential part of heart transplantation. Despite the shortage of donor hearts, donor heart procurement from brain-dead organ donors remains low in France, which may be explained by the increasing proportion of high-risk donors, as well as the mismatch between donor assessment and the transplant team's expectations. Improving donor and donor heart assessment is essential to improve the low utilization rate of available donor hearts without increasing post-transplant recipient mortality. This document provides information to practitioners involved in brain-dead donor management, evaluation and selection, concerning the place of medical history, electrocardiography, cardiac imaging, biomarkers and haemodynamic and arrhythmia assessment in the characterization of potential heart donors.

Associated Clinical and Laboratory Markers of Donor on Allograft Function After Heart Transplant

Introduction

Primary graft dysfunction is a major cause of mortality after heart transplantation.

Objective

To evaluate correlations between donor-related clinical/biochemical markers and the occurrence of primary graft dysfunction/clinical outcomes of recipients within 30 days of transplant.

Methods

The prospective study involved 43 donor/recipient pairs. Data collected from donors included demographic and echocardiographic information, noradrenaline administration rates and concentrations of soluble tumor necrosis factor receptors (sTNFR1 and sTNFR2), interleukins (IL-6 and IL-10), monocyte chemoattractant protein-1, C-reactive protein and cardiac troponin I. Data collected from recipients included operating, cardiopulmonary bypass, intensive care unit and hospitalization times, inotrope administration and left/right ventricular function through echocardiography.

Results

Recipients who developed moderate/severe left ventricular dysfunction had received organs from significantly older donors (P =0.020). Recipients from donors who required moderate/high doses of noradrenaline (>0.23 µg/kg/min) around harvesting time exhibited lower post-transplant ventricular ejection fractions (P =0.002) and required longer CPB times (P =0.039). Significantly higher concentrations of sTNFR1 (P =0.014) and sTNFR2 (P =0.030) in donors were associated with reduced intensive care unit times (≤5 days) in recipients, while higher donor IL-6 (P =0.029) and IL-10 (P =0.037) levels were correlated with reduced hospitalization times (≤25 days) in recipients. Recipients who required moderate/high levels of noradrenaline for weaning off cardiopulmonary bypass were associated with lower donor concentrations of sTNFR2 (P =0.028) and IL-6 (P =0.001).

Conclusion

High levels of sTNFR1, sTNFR2, IL-6 and IL-10 in donors were associated with enhanced evolution in recipients. Allografts from older donors, or from those treated with noradrenaline doses >0.23 µg/kg/min, were more frequently affected by primary graft dysfunction within 30 days of surgery.

Computational Models for Transplant Biomarker Discovery

Translational medicine offers a rich promise for improved diagnostics and drug discovery for biomedical research in the field of transplantation, where continued unmet diagnostic and therapeutic needs persist. Current advent of genomics and proteomics profiling called "omics" provides new resources to develop novel biomarkers for clinical routine. Establishing such a marker system heavily depends on appropriate applications of computational algorithms and software, which are basically based on mathematical theories and models. Understanding these theories would help to apply appropriate algorithms to ensure biomarker systems successful. Here, we review the key advances in theories and mathematical models relevant to transplant biomarker developments. Advantages and limitations inherent inside these models are discussed. The principles of key -computational approaches for selecting efficiently the best subset of biomarkers from high--dimensional omics data are highlighted. Prediction models are also introduced, and the integration of multi-microarray data is also discussed. Appreciating these key advances would help to accelerate the development of clinically reliable biomarker systems.

B-type natriuretic peptide trends after pediatric heart transplantation

BNP is increasingly utilized in the management of pediatric HT recipients. Performing a retrospective single-center chart review, we sought to describe BNP changes during the first year after HT and identify factors that affect its trend. After exclusion for rejection, 316 BNP levels from 50 patients were evaluated. BNP underwent an exponential decline 120 days after HT followed by a plateau. Log10 BNP decline strongly correlated with time (r = -0.70, p < 0.0001). Initial BNP was less in pretransplant VAD (p = 0.0016) and lower post-HT inotrope use (p = 0.0043). Infant recipients, IT >4 h, and those bridged medically were associated with higher plateau BNP. Multivariable logistic regression demonstrated IT >4 h independently predicted plateau BNP in the upper quartile (OR 7.1, p = 0.02). No significant change in BNP coincided with rejection (N = 6 patients) without severe hemodynamic compromise. BNP correlated modestly with right atrial pressure (r = 0.4652, p < 0.0001) and pulmonary capillary wedge pressure (r = 0.2660, p < 0.001), but poorly with echocardiogram (r = -0.18, p = 0.003). Trending BNP could help provide insight into how the graft recovers after HT and IT >4 h independently predicted higher plateau BNP and may reflect subtle changes in graft performance.