Racial Differences in Donor-Derived Cell-Free DNA and Mitochondrial DNA After Heart Transplantation, on Behalf of the GRAfT Investigators.

BACKGROUND: Black heart transplant patients are at higher risk of acute rejection (AR) and death than White patients. We hypothesized that this risk may be associated with higher levels of donor-derived cell-free DNA (dd-cfDNA) and cell-free mitochondrial DNA. METHODS: The Genomic Research Alliance for Transplantation is a multicenter, prospective, longitudinal cohort study. Sequencing was used to quantitate dd-cfDNA and polymerase chain reaction to quantitate cell-free mitochondrial DNA in plasma. AR was defined as ≥2R cellular rejection or ≥1 antibody-mediated rejection. The primary composite outcome was AR, graft dysfunction (left ventricular ejection fraction <50% and decrease by ≥10%), or death. RESULTS: We included 148 patients (65 Black patients and 83 White patients), median age was 56 years and 30% female sex. The incidence of AR was higher in Black patients compared with White patients (43% versus 19%; P=0.002). Antibody-mediated rejection occurred predominantly in Black patients with a prevalence of 20% versus 2% (P<0.001). After transplant, Black patients had higher levels of dd-cfDNA, 0.09% (interquartile range, 0.001-0.30) compared with White patients, 0.05% (interquartile range, 0.001-0.23; P=0.003). Beyond 6 months, Black patients showed a persistent rise in dd-cfDNA with higher levels compared with White patients. Cell-free mitochondrial DNA was higher in Black patients (185 788 copies/mL; interquartile range, 101 252-422 133) compared with White patients (133 841 copies/mL; interquartile range, 75 346-337 990; P<0.001). The primary composite outcome occurred in 43% and 55% of Black patients at 1 and 2 years, compared with 23% and 27% in White patients, P<0.001. In a multivariable model, Black patient race (hazard ratio, 2.61 [95% CI, 1.35-5.04]; P=0.004) and %dd-cfDNA (hazard ratio, 1.15 [95% CI, 1.03-1.28]; P=0.010) were associated with the primary composite outcome. CONCLUSIONS: Elevated dd-cfDNA and cell-free mitochondrial DNA after heart transplant may mechanistically be implicated in the higher incidence of AR and worse clinical outcomes in Black transplant recipients. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02423070.

Efficacy and Safety of Acoramidis in Transthyretin Amyloid Cardiomyopathy.

BACKGROUND: Transthyretin amyloid cardiomyopathy is characterized by the deposition of misfolded monomeric transthyretin (TTR) in the heart. Acoramidis is a high-affinity TTR stabilizer that acts to inhibit dissociation of tetrameric TTR and leads to more than 90% stabilization across the dosing interval as measured ex vivo. METHODS: In this phase 3, double-blind trial, we randomly assigned patients with transthyretin amyloid cardiomyopathy in a 2:1 ratio to receive acoramidis hydrochloride at a dose of 800 mg twice daily or matching placebo for 30 months. Efficacy was assessed in the patients who had an estimated glomerular filtration rate of at least 30 ml per minute per 1.73 m2 of body-surface area. The four-step primary hierarchical analysis included death from any cause, cardiovascular-related hospitalization, the change from baseline in the N-terminal pro-B-type natriuretic peptide (NT-proBNP) level, and the change from baseline in the 6-minute walk distance. We used the Finkelstein-Schoenfeld method to compare all potential pairs of patients within strata to generate a P value. Key secondary outcomes were death from any cause, the 6-minute walk distance, the score on the Kansas City Cardiomyopathy Questionnaire-Overall Summary, and the serum TTR level. RESULTS: A total of 632 patients underwent randomization. The primary analysis favored acoramidis over placebo (P<0.001); the corresponding win ratio was 1.8 (95% confidence interval [CI], 1.4 to 2.2), with 63.7% of pairwise comparisons favoring acoramidis and 35.9% favoring placebo. Together, death from any cause and cardiovascular-related hospitalization contributed more than half the wins and losses to the win ratio (58% of all pairwise comparisons); NT-proBNP pairwise comparisons yielded the highest ratio of wins to losses (23.3% vs. 7.0%). The overall incidence of adverse events was similar in the acoramidis group and the placebo group (98.1% and 97.6%, respectively); serious adverse events were reported in 54.6% and 64.9% of the patients. CONCLUSIONS: In patients with transthyretin amyloid cardiomyopathy, the receipt of acoramidis resulted in a significantly better four-step primary hierarchical outcome containing components of mortality, morbidity, and function than placebo. Adverse events were similar in the two groups. (Funded by BridgeBio Pharma; ATTRibute-CM ClinicalTrials.gov number, NCT03860935.).

Multicenter study of universal prophylaxis versus pre-emptive therapy for patients at intermediate risk (R+) for CMV following heart transplantation.

INTRODUCTION: Heart transplant (HT) recipients with prior exposure to cytomegalovirus (CMV R+) are considered intermediate risk for CMV-related complications. Consensus guidelines allow for either universal prophylaxis (UP) or preemptive therapy (PET) (serial CMV testing) approaches to CMV prevention in such patients. Whether an optimal approach to mitigate CMV related risks exists in this setting remains uncertain. We therefore assessed the utility of PET as compared to UP in CMV R+ HT recipients. METHODS: Retrospective analysis of all CMV R+ HT recipients from 6 U.S. centers between 2010 and 2018 was performed. The primary outcome was the development of CMV DNAemia or end-organ disease resulting in the initiation/escalation of anti-CMV therapy. The secondary outcome was CMV-related hospitalization. Additional outcomes included incidence of acute cellular rejection (ACR) ≥ grade 2R, death, cardiac allograft vasculopathy (CAV), and leukopenia. RESULTS: Of 563 CMV R+ HT recipients, 344 (61.1%) received UP. PET was associated with increased risk for the primary (adjusted HR 3.95, 95% CI: 2.65-5.88, p < .001) and secondary (adjusted HR 3.19, 95% CI: 1.47-6.94, p = .004) outcomes, and with increased ACR ≥ grade 2R (PET 59.4% vs. UP 34.4%, p < .001). Incidence of detectable CAV was similar at 1 year (PET 8.2% vs. UP 9.5%, p = .698). UP was associated with increased incidence of leukopenia within 6 months post-HT (PET 34.7% vs. UP 43.6%, p = .036). CONCLUSION: The use of a PET CMV prophylaxis strategy in intermediate risk HT recipients associated with increased risk of CMV infection and CMV-related hospitalization, and may associate with worse post-HT graft outcomes.

A bridge-to-bridge approach to heart transplantation using extracorporeal membrane oxygenation and total artificial heart.

BACKGROUND: This study aims to describe the outcomes after heart transplantation using a bridge-to-bridge strategy with a sequence of extracorporeal membrane oxygenation (ECMO) support followed by temporary total artificial heart implantation (TAH-t). METHODS: A retrospective, multicenter analysis of 54 patients who underwent TAH-t implantation following an ECMO for cardiogenic shock was performed (ECMO-TAH-t group). A control group of 163 patients who underwent TAH-t implantation as a direct bridge to transplantation (TAH-t group) was used to assess this strategy's impact on outcomes. RESULTS: Fifty-four patients, averaging 47 ± 13 year old, underwent implantation of a TAH-t after 5.3 ± 3.4 days of ECMO perfusion for cardiogenic shock. In the ECMO-TAH-t group, 20 patients (20/54%; 37%) died after TAH-t implantation and 57 patients (57/163%; 35%) died in the TAH-t group (Gray test; P = .49). The top 3 causes of death of patients on TAH-t support were multisystem organ failure (40%), sepsis (20%), and neurologic events (20%). Overall, 32 patients (32/54%; 59%) underwent heart transplantation in the ECMO-TAH-t group compared with 106 patients (106/163%, 65%) in the TAH-t group (P = .44). No significant difference in survival was observed at 6 months, 1 year, and 3 years after heart transplant (ECMO-TAH-t group: 94%, 87%, and 80% vs 87%, 83%, and 76% in the TAH-t group, respectively). Deterioration of liver function (bilirubin, aspartate transaminase, and alanine aminotransferase levels on TAH-t) was associated with increased mortality before heart transplant in both groups. CONCLUSIONS: Sequential bridging from ECMO to TAH-t followed by heart transplantation is a viable option for a group of highly selected patients.

Circulating microRNAs in cellular and antibody-mediated heart transplant rejection.

BACKGROUND: Noninvasive monitoring of heart allograft health is important to improve clinical outcomes. MicroRNAs (miRs) are promising biomarkers of cardiovascular disease and limited studies suggest they can be used to noninvasively diagnose acute heart transplant rejection. METHODS: The Genomic Research Alliance for Transplantation (GRAfT) is a multicenter prospective cohort study that phenotyped heart transplant patients from 5 mid-Atlantic centers. Patients who had no history of rejection after transplant were compared to patients with acute cellular rejection (ACR) or antibody-mediated rejection (AMR). Small RNA sequencing was performed on plasma samples collected at the time of an endomyocardial biopsy. Differential miR expression was performed with adjustment for clinical covariates. Regression was used to develop miR panels with high diagnostic accuracy for ACR and AMR. These panels were then validated in independent samples from GRAfT and Stanford University. Receiver operating characteristic curves were generated and area under the curve (AUC) statistics calculated. Distinct ACR and AMR clinical scores were developed to translate miR expression data for clinical use. RESULTS: The GRAfT cohort had a median age of 52 years, with 35% females and 45% Black patients. Between GRAfT and Stanford, we included 157 heart transplant patients: 108 controls and 49 with rejection (50 ACR and 38 AMR episodes). After differential miR expression and regression analysis, we identified 12 miRs that accurately discriminate ACR and 17 miRs in AMR. Independent validation of the miR panels within GRAfT led to an ACR AUC 0.92 (95% confidence interval [CI]: 0.86-0.98) and AMR AUC 0.82 (95% CI: 0.74-0.90). The externally validated ACR AUC was 0.72 (95% CI: 0.59-0.82). We developed distinct ACR and AMR miR clinical scores (range 0-100), a score ≥ 65, identified ACR with 86% sensitivity, 76% specificity, and 98% negative predictive value, for AMR score performance was 82%, 84% and 97%, respectively. CONCLUSIONS: We identified novel miRs that had excellent performance to noninvasively diagnose acute rejection after heart transplantation. Once rigorously validated, the unique clinical ACR and AMR scores usher in an era whereby genomic biomarkers can be used to screen and diagnose the subtype of rejection. These novel biomarkers may potentially alleviate the need for an endomyocardial biopsy while facilitating the initiation of targeted therapy based on the noninvasive diagnosis of ACR or AMR.

Percutaneous approach to left ventricular assist device decommissioning.

OBJECTIVE: To assess the outcomes of a single-center experience with percutaneous left ventricular assist device (LVAD) decommissioning. BACKGROUND: Patients with LVADs may eventually require their removal, either due to recovery of left ventricular function or recurrent complications. Traditionally, withdrawal of LVAD support has been managed with surgical device explantation, which carries significant procedural risks. Transcatheter LVAD decommissioning, with outflow graft occlusion and driveline transection, has recently been described as an alternative to surgical removal. METHODS: Here, we report on a retrospective cohort of five consecutive cases treated with transcatheter LVAD decommissioning. RESULTS: The procedure was effective in all cases, and no patient experienced procedure-related complications. At midterm follow-up, the three patients who had myocardial function recovery were alive and had not experienced heart failure-related symptoms or complications. CONCLUSION: Percutaneous LVAD decommissioning appears to be a safe and effective approach to LVAD treatment discontinuation.

Higher levels of allograft injury in black patients early after heart transplantation.

Black patients suffer higher rates of antibody-mediated rejection and have worse long-term graft survival after heart transplantation. Donor-derived cell free DNA (ddcfDNA) is released into the blood following allograft injury. This study analyzed %ddcfDNA in 63 heart transplant recipients categorized by Black and non-Black race, during the first 200 days after transplant. Immediately after transplant, %ddcfDNA was higher for Black patients (mean [SE]: 8.3% [1.3%] vs 3.2% [1.2%], p = 0.001). In the first week post-transplant, the rate of decay in %ddcfDNA was similar (0.7% [0.68] vs 0.7% [0.11], p = 0.78), and values declined in both groups to a comparable plateau at 7 days post-transplant (0.46% [0.03] vs 0.45% [0.04], p = 0.78). The proportion of Black patients experiencing AMR was higher than non-Black patients (21% vs 9% [hazard ratio of 2.61 [95% confidence interval: 0.651-10.43], p = 0.18). Black patients were more likely to receive a race mismatched organ than non-Black patients (69% vs 35%, p = 0.01), which may explain the higher levels of early allograft injury.

Combined Heart-Liver and Domino Liver Transplantation in Familial Amyloidosis.

BACKGROUND: Combined heart-liver transplantation (CHLT) is the only curative option for patients with concomitant pathology affecting the heart and liver. In some cases, the native livers of familial amyloidosis (FA) patients may be suitable for domino transplantation into other recipients. METHODS: Retrospective analysis (2013 to 2019) of all CHLT at our center was performed. Continuous data were presented as mean with standard deviation and discrete variables as percentages. RESULTS: Familial amyloidosis was the indication for CHLT in 5 out of 6 patients. The mean recipient age was 55 ± 5.62 years. Two patients were bridged with total artificial heart. The mean model for end-stage liver disease score at transplant was 17.17 ± 3.7. Two explanted livers were used for transplantation in a domino fashion. The median intensive care and hospital stays were 5.5 and 19 days, respectively. Complications included renal failure (1), groin abscess (1), pulmonary embolism (1), and cardiac rejection (1). Patient and graft survival for both organs was 100% at a median follow-up of 59 (range 20-76) months. DISCUSSION: Combined heart-liver transplantation for FA achieves excellent outcomes. The possible use of livers explanted from patients with FA for domino liver transplantation can contribute to the liver donor pool.

Caregiver Health-Related Quality of Life, Burden, and Patient Outcomes in Ambulatory Advanced Heart Failure: A Report From REVIVAL.

Background Heart failure (HF) imposes significant burden on patients and caregivers. Longitudinal data on caregiver health-related quality of life (HRQOL) and burden in ambulatory advanced HF are limited. Methods and Results Ambulatory patients with advanced HF (n=400) and their participating caregivers (n=95) enrolled in REVIVAL (Registry Evaluation of Vital Information for VADs [Ventricular Assist Devices] in Ambulatory Life) were followed up for 24 months, or until patient death, left ventricular assist device implantation, heart transplantation, or loss to follow-up. Caregiver HRQOL (EuroQol Visual Analog Scale) and burden (Oberst Caregiving Burden Scale) did not change significantly from baseline to follow-up. At time of caregiver enrollment, better patient HRQOL by Kansas City Cardiomyopathy Questionnaire was associated with better caregiver HRQOL (P=0.007) and less burden by both time spent (P<0.0001) and difficulty (P=0.0007) of caregiving tasks. On longitudinal analyses adjusted for baseline values, better patient HRQOL (P=0.034) and being a married caregiver (P=0.016) were independently associated with better caregiver HRQOL. Patients with participating caregivers (versus without) were more likely to prefer left ventricular assist device therapy over time (odds ratio, 1.43; 95% CI, 1.03-1.99; P=0.034). Among patients with participating caregivers, those with nonmarried (versus married) caregivers were at higher composite risk of HF hospitalization, death, heart transplantation or left ventricular assist device implantation (hazard ratio, 2.99; 95% CI, 1.29-6.96; P=0.011). Conclusions Patient and caregiver characteristics may impact their HRQOL and other health outcomes over time. Understanding the patient-caregiver relationship may better inform medical decision making and outcomes in ambulatory advanced HF.

Disease-Modifying Treatments for Transthyretin Amyloidosis.

ABSTRACT: The transthyretin (TTR) amyloidoses result from misfolding of the protein leading to fibril formation and aggregation as amyloid deposits in predominantly the cardiovascular and nervous systems. Cardiac involvement can manifest as heart failure, arrhythmias, and valvular disease. Neurologic involvement can cause sensorimotor polyneuropathies, mononeuropathies, and dysautonomia. Previously, treatment has focused on management of these symptoms and disease sequelae, with a high rate of mortality due to the absence of disease-modifying therapies. In this article, we review novel treatments focusing on 3 mechanistic pathways: (1) silencing of the TTR gene to suppress production, (2) stabilizing of TTR tetramers to prevent misfolding, or (3) disrupting of existing TTR amyloid fibrils to promote reabsorption.

An interventional approach to left ventricular assist device outflow graft obstruction.

BACKGROUND: LVADs provide life-sustaining treatment for patients with heart failure, but their complexity allows for complications. One complication, LVAD outflow graft obstruction, may be misdiagnosed as intraluminal thrombus, when more often it is extraluminal compression from biodebris accumulation. It can often be treated endovascularly with stenting. This case series describes diagnostic and procedural techniques for the treatment of left ventricular assist device (LVAD) outflow graft obstruction. METHODS: We present four patients with LVADs who developed LVAD outflow graft obstruction within the bend relief-covered segment. All were initially diagnosed with computed tomographic angiography (CTA). All underwent invasive evaluation with intravascular ultrasound (IVUS), then were treated with stenting. After misdiagnosing a twist, we developed the technique of balloon "graftoplasty" to ensure suitability for stent delivery in subsequent cases. RESULTS: All patients presented with low-flow alarms and symptoms of low output, and were diagnosed with outflow graft obstruction by CTA. In all four, IVUS confirmed an extraluminal etiology. Patient 1 was treated with stenting and had a good outcome. Patient 2's obstruction was from twisting, rather than biodebris accumulation, and had sub-optimal stent expansion and ultimately required surgery. Balloon "graftoplasty" was used in subsequent cases to ensure subsequent stent expansion. Patients 3 and 4 were successfully stented. All improved after treatment. CONCLUSIONS: In patients with LVAD outflow graft obstruction, IVUS can distinguish intraluminal thrombus from extraluminal compression. Balloon "graftoplasty" can ensure that the outflow graft will respond to stenting. Many cases of LVAD outflow graft obstruction should be amenable to endovascular treatment.

Predictive Value of Cardiopulmonary Exercise Testing Parameters in Ambulatory Advanced Heart Failure.

OBJECTIVES: This study sought to determine cardiopulmonary exercise (CPX) predictors of the combined outcome of durable mechanical circulatory support (MCS), transplantation, or death at 1 year among patients with ambulatory advanced heart failure (HF). BACKGROUND: Optimal CPX predictors of outcomes in contemporary ambulatory advanced HF patients are unclear. METHODS: REVIVAL (Registry Evaluation of Vital Information for ventricular assist devices [VADs] in Ambulatory Life) enrolled 400 systolic HF patients, INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) profiles 4-7. CPX was performed by 273 subjects 2 ± 1 months after study enrollment. Discriminative power of maximal (peak oxygen consumption [peak VO2]; VO2 pulse, circulatory power [CP]; peak systolic blood pressure â€¢ peak VO2], peak end-tidal pressure CO2 [PEtCO2], and peak Borg scale score) and submaximal CPX parameters (ventilatory efficiency [VE/VCO2 slope]; VO2 at anaerobic threshold [VO2AT]; and oxygen uptake efficiency slope [OUES]) to predict the composite outcome were assessed by univariate and multivariate Cox regression and Harrell's concordance statistic. RESULTS: At 1 year, there were 39 events (6 transplants, 15 deaths, 18 MCS implantations). Peak VO2, VO2AT, OUES, peak PEtCO2, and CP were higher in the no-event group (all p < 0.001), whereas VE/VCO2 slope was lower (p < 0.0001); respiratory exchange ratio was not different. CP (hazard ratio [HR]: 0.89; p = 0.001), VE/VCO2 slope (HR: 1.05; p = 0.001), and peak Borg scale score (HR: 1.20; p = 0.005) were significant predictors on multivariate analysis (model C-statistic: 0.80). CONCLUSIONS: Among patients with ambulatory advanced HF, the strongest maximal and submaximal CPX predictor of MCS implantation, transplantation, or death at 1 year were CP and VE/VCO2, respectively. The patient-reported measure of exercise effort (Borg scale score) contributed substantially to the prediction of outcomes, a surprising and novel finding that warrants further investigation. (Registry Evaluation of Vital Information for VADs in Ambulatory Life [REVIVAL]; NCT01369407).

Outcomes after heart transplantation and total artificial heart implantation: A multicenter study.

BACKGROUND: We sought to assess the outcomes after heart transplantation (HT) of patients supported with a temporary total artificial heart (t-TAH) as a bridge to transplantation in high-volume centers. METHODS: A retrospective analysis of 217 consecutive patients who underwent t-TAH (SynCardia Systems, Tucson, Arizona) implantation between January 2014 and May 2019 in 6 high-volume North American centers was performed. End points included survival and adverse events after t-TAH and HT. RESULTS: The mean age of patients was 49 ± 12 years, and heart failure etiologies were non-ischemic dilated cardiomyopathy (36%), ischemic (25%), restrictive (12%), and cardiac graft failure (9%). A total of 101 (48%) patients had Interagency Registry for Mechanically Assisted Circulatory Support patient profile 1, and 65 (31%) had Interagency Registry for Mechanically Assisted Circulatory Support patient profile 2. At the end of the study period, 138 of 217 (63.5%) patients had undergone HT, and 75 (34.5%) patients died before HT. The mean time between t-TAH implantation and HT averaged 181 ± 179 days (range: 0-849) and the mean follow-up after HT was 35 ± 25 months. The overall survival in the entire cohort was 75%, 64%, and 58% at 1, 2, and 5 years, respectively. Post-transplant survival was 88%, 84%, 79%, and 74% at 6 months, 1 year, 2 years, and 5 years, respectively. Among the 32 patients (23%) who died after HT, the main causes of death were chronic allograft vasculopathy (25%), multiorgan failure (21.8%), sepsis (15.6%), and stroke (9%). CONCLUSION: In this multicenter study, almost two thirds of patients implanted with a t-TAH could be transplanted. The overall and post-transplantation survival after t-TAH was satisfactory in these critically ill patients.