Citations

Abstract Background A higher serum phosphorus level, although within the normal range has been linked to coronary artery and aortic calcification in the non-transplant population. Coronary calcification is mostly associated with donor-derived lesions, and is uncommon within the first years after heart transplantation. Purpose We aimed to investigate the association of phosphorus levels with plaque calcification after heart transplantation. Methods A total of 156 patients who underwent virtual histology intravascular ultrasound (VH-IVUS) studies for cardiac allograft vasculopathy (CAV) surveillance and had fasting serum phosphorus levels <4.5 mg/dL, were included in the analyses. IVUS analyses were performed in the proximal left anterior descending artery, and plaque composition of dense calcium (DC) was evaluated using VH-IVUS, and presented as percent DC of total plaque volume. The patients were separated into 3 groups according to tertiles of serum phosphorus levels. Results Mean recipient and donor ages were 54±13 and 31±14 years, respectively. Mean serum phosphorus in recipients was 3.5±0.6 mg/dL, with median time after transplantation at the IVUS studies of 6 (3,10) years. There were no significant differences in %DC between phosphorus tertiles in patients who underwent IVUS within 6 years after transplantation (p=0.11, Fig. 1A). However, beyond 6 years after transplantation, we observed an incremental association between phosphorus levels and the extent of calcification (p=0.02, Fig. 1B). In this group, serum phosphorus levels significantly correlated with %DC (standardized β=0.29, P=0.008), and this correlation remained significant after adjustment for donor age, recipient age, and eGFR (standardized β=0.26, P=0.001). Conclusion Higher serum phosphorus levels were associated with a level-dependent increase in calcified coronary artery plaque in patients starting 6 years post heart transplant. Long-term exposure to higher serum phosphorus, even within the normal range, might promote plaque calcification after heart transplantation. Funding Acknowledgement Type of funding sources: None.

Abstract Background An artificial intelligence (AI) algorithm detecting age from 12-lead ECG has been suggested to signal “physiological age” of the individual. Importantly, increased physiological age gauged by an increased difference between ECG-age and chronological age has been associated with higher risk of cardiac events in non-transplant population. Purpose We sought to investigate the validity of the AI-derived ECG-age algorithm in patients who underwent heart transplantation and its relationship to major adverse cardiovascular events (MACE). Methods A total of 489 consecutive patients who had undergone heart transplantation in our institution between 1994 and 2018 were studied. AI-ECG age was calculated by a previously-trained artificial intelligence (AI) algorithm using a 12-lead ECG per patient. ECGs used in the training process of the algorithm were excluded. The average of the ECG-ages within one year before and one year after heart transplantation was used to represent pre- and post-transplant ECG-ages. MACE was defined as any incidence of revascularization, re-transplantation, and death. Results Pre-transplant ECG-age (mean 63±10 years) correlated significantly with recipient chronological age (mean 50±13 years, r=0.57, p<0.0001), but this correlation between recipient and ECG-ages was weakened after transplantation (mean post-transplant ECG age of 55±10 years, r=0.34, p<0.0001). Interestingly, post-transplant ECG-age correlated significantly with donor age (mean ECG age of 55±10 years vs. mean donor age of 32±13 years, r=0.42, p<0.0001). During a median (IQR) follow-up of 9 (5, 14) years, 251 patients had MACE. Mean change in ECG age after transplantation compared to before was −8.8±12.7 years. Patients who had an increase in ECG-age after compared to before transplantation showed increased risk of MACE (HR: 1.53 [1.16, 2.01], p=0.002), independent of recipient and donor ages (adjusted HR: 1.68 [1.26, 2.25], p=0.001); whereas there were no significant differences in risk of MACE in patients who were transplanted with an older donor heart (HR: 1.07 [0.77, 1.50], p=0.66). In a Kaplan Meier survival analysis, those with increased ECG-age after transplantation had significantly lower MACE-free survival compared to those with decreased ECG-age. (Log-rank P=0.002; Wilcoxon P=0.001) (Figure) Conclusion Post-transplant ECG-age correlates more faithfully with the donor's than the recipient's chronological age, suggesting that ECG-age more closely reflects cardiac age than the patient age. Furthermore, ECG-age derived cardiac aging after transplantation is associated with higher risk of MACE. Funding Acknowledgement Type of funding sources: None.

Abstract Aims Cardiac allograft vasculopathy (CAV) is the major cause of increased morbidity and mortality after heart transplantation. Peripheral endothelial dysfunction (PED) is associated with early atherosclerosis and future risk of major adverse cardiovascular events (MACE) in non-heart transplant population. We aimed to investigate the association of PED with future MACE, and plaque progression assessed by intravascular ultrasound (IVUS) after heart transplantation. Methods and results We included 66 transplant patients who underwent serial IVUS surveillance for CAV and baseline assessment of peripheral endothelial function using reactive hyperaemia peripheral arterial tonometry. PED was defined as reactive hyperaemia index < 2. The primary endpoint of the study was to investigate the association of PED with CAV progression assessed by intravascular ultrasound (IVUS). CAV progression was assessed as the change (Δ) in plaque volume divided by segment length, and Δ plaque index (plaque volume/vessel volume), adjusted for the time between IVUS measurements (median 3.0 [2.2, 3.1] years). The secondary endpoint was to investigate the association between PED and future MACE, which was defined as any incident of revascularization, heart failure hospitalization, stroke, myocardial infarction, re-transplantation, and death. Patients with PED (n = 27) had more yearly plaque progression (0.50 ± 0.66 vs. 0.15 ± 0.50 mm3/mm/year, P = 0.02) and a higher Δ plaque index (2.41 ± 2.53% vs. 0.69 ± 2.22%, P = 0.01). Patients with PED were more likely to experience MACE during a median follow-up of 8.2 years (interquartile range [7.6, 8.4]), after adjustment for potential cofounders such as age, high-density lipoprotein cholesterol levels, total rejection score, baseline International Society for Heart & Lung Transplantation CAV grade, and indication of transplantation. (hazard ratio 2.15, 95% confidence interval [1.09, 4.23], P = 0.03). Conclusions Peripheral endothelial dysfunction is associated with increased plaque progression and adverse long-term cardiovascular outcomes in transplant patients. PED assessment might be a useful clinical tool for risk stratification after heart transplantation.

The World Health Organization Classification of Tumours of Haematopoietic and Lymphoid Tissues (WHO 2017) included updated criteria for diagnosis and classification of post-transplant lymphoproliferative disorders (PTLDs). This study evaluated the clinicopathologic spectrum using WHO 2017 criteria and adult PTLD patients’ outcomes over 30 years between 1987 and 2017 at Mayo Clinic (Rochester, MN). Patients were retrospectively reviewed for clinical features, outcomes, and diagnostic pathology material and classified based on WHO 2017 criteria. A total of 227 patients were diagnosed with PTLD, with a median time from transplant to PTLD of 45 months. PTLD occurred >1 year after transplant in 149 (66%) patients. Monomorphic PTLD was the most common subtype (173, 76%), with diffuse large B cell lymphoma as the commonest morphology (n = 137). Epstein-Barr virus was positive in 61% of total cases and 90% of PTLD that developed within 1 year from transplant. The median event-free survival (EFS) and overall survival for the entire cohort were 21 months (95% confidence interval [CI]: 9–35) and 82 months (95% CI: 39–115), respectively. The EFS or overall survival was not impacted by Epstein-Barr virus status but differed based on WHO subtypes and year of diagnosis. Management changed over time with increased use of rituximab or chemotherapy + immunosuppression reduction as initial therapy. When compared to the matched general population and de novo diffuse large B cell lymphoma, patients not achieving EFS 24 status (no progression/treatment or death within 24 mo of diagnosis) had a worse standardized mortality ratio 16.75 (95% CI: 13.91–20) versus SMR 1.72 (95% CI: 1.26–2.28) in those who achieved EFS24. Cause of death was mostly attributed to non-lymphoma–related causes in those achieving EFS 24.

Background and Purpose: Less is known about the risk factors and outcomes associated with stroke in the current era of increasing heart transplantation (HT) being performed in older patients. The impact of immunosuppression on risk of stroke has not yet been previously studied. We aimed to determine the incidence, risk factors and outcomes of stroke after HT. Methods: We retrospectively analyzed the incidence of ischemic and hemorrhagic strokes and associated outcomes in all consecutive HT recipients transplanted between 1994 and 2016 at a single institution. Results: Of 529 patients who underwent HT, 57 (10.7%) developed stroke, 8.1% had an ischemic events and (2.6%) had a hemorrhagic stroke. Age at HT (adjusted hazard ratio [HR] 1.33; P =0.03) and diabetes (HR, 2.60; P =0.02) were associated with increased risk of ischemic events. Patients with stroke (any type) were more likely to have worse kidney function (HR, 1.81; P =0.02) whereas patients with ischemic events were more likely to undergo combined organ transplantation (HR, 2.01; P =0.05). Cytomegalovirus infection was found to be associated with increased risk of any stroke (HR, 2.09; P =0.02).Conversion from calcineurin inhibitor to sirolimus-based immunosuppression was not found to be associated with a significant change in stroke risk (HR, 1.39; P =0. 45) compared with calcineurin inhibitor maintenance therapy. Stroke of any type and ischemic events were independently associated with increased risk of death (HR, 1.90; P =0.001 and HR, 2.14; P <0.001, respectively). Conclusions: Stroke after HT is associated with increased mortality. Older age at HT, diabetes, renal dysfunction, and CMV infection were associated with greater risk of stroke.

Abstract Background Invasive fungal infection (IFI) in heart transplant recipients is associated with poor outcomes. Estimated risk of 1‐year IFI in heart transplant recipients is 3.4–8.6% with risk factors inconsistently identified in previous studies. The role of antifungal prophylaxis is unclear. The transplant program at Mayo Clinic provides 6 months of universal azole prophylaxis for those heart transplant recipients in Arizona. We sought to define risk factors for 1‐year IFI and determine the effect of antifungal prophylaxis. Methods We conducted a retrospective cohort study of patients undergoing heart transplantation at Mayo Clinic from January 2000 to March 2019. We analyzed demographics, details of transplant hospitalization, antifungal prophylaxis, and fungal infection. Multivariable Cox analyses were performed to identify risk factors of 1‐year IFI and impact of IFI on posttransplant mortality. Results A total of 966 heart transplant recipients were identified with a median age of 56 years (IQR 47, 62). A total of 444 patients received antifungal prophylaxis. Over 1‐year follow‐up, 62 patients developed IFI with a cumulative incidence of 6.4%. In multivariable analysis, factors associated with IFI were renal replacement therapy (RRT) (HR 3.24, 95% CI 1.65–6.39), allograft rejection (HR 2.33, 95% CI 1.25–4.34), and antifungal prophylaxis (HR 0.32, 95% CI 0.11–0.96). RRT was also associated with invasive mold infection (HR 3.00, 95% CI 1.29–6.97). Conclusions RRT and allograft rejection after transplantation are associated with 1‐year IFI, and RRT is also associated with invasive mold infection. Antifungal prophylaxis appears to be protective and further study is needed in the heart transplant population.

In contrast to the wide application of zebrafish embryos in developmental genetic studies, the value of an adult zebrafish to dissect signaling pathways in human diseases such as cardiomyopathy remains largely elusive. Previously, we have established anemic tr265/tr265 fish as the first adult zebrafish model of cardiomyopathy. Here, we generate the second adult zebrafish cardiomyopathy model induced by injection of a single bolus of doxorubicin (DOX). Despite their different pathogenesis, cardiac enlargement induced by either anemia or DOX can be effectively attenuated by inhibition of target of rapamycin (TOR) signaling via rapamycin treatment. However, along the progression of both models, we have also detected dynamic TOR activity and distinct effects of TOR signaling inhibition at different stages of pathogenesis. To assess the long term effects of TOR haploinsufficiency, we utilized a zebrafish target of rapamycin (ztor) mutant that was identified from a mutagenesis screen. We show that sustained TOR inhibition in ztor/+ improved cardiac function, prevented pathological remodeling events, and ultimately reduced mortality in both adult fish models of cardiomyopathy. Mechanistically, these cardioprotective effects are conveyed by the anti-hypertrophy, anti-apoptosis, and pro-autophagy function of TOR signaling inhibition. Together, our results prove adult zebrafish as a novel vertebrate model for human cardiomyopathies and provide genetic evidences for a cardioprotective function of TOR signaling inhibition in different forms of cardiomyopathies.

Background: Left ventricular assist devices as destination therapy (DT-LVAD) have been shown to decrease mortality compared with medical management, and can improve quality of life for many patients with advanced heart failure. However, while most patients live longer with DT-LVAD than they would have with medical therapy, deaths still occur. We sought to systematically examine the end-of-life care of patients who died with a DT-LVAD at a single center. Methods: All patients undergoing DT-LVAD at the Mayo Clinic in Rochester, Minnesota from January 1, 2007 through September 30, 2014 who subsequently died prior to July 1, 2015 were included. The cause of death was determined based on review of documentation in the electronic medical record, including autopsy reports, death certificates and clinical notes. Details about palliative care consultations, hospice enrollment, hospitalizations, and device deactivation at the end-of-life were obtained from the electronic medical record. Results: Of 89 patients that died with a DT-LVAD (84 HeartMate II, 3 HeartWare, 2 Heartmate XVE, mean age at death 66.1 years), the mean (standard deviation) time from LVAD implantation to death was 2.0 (1.9) years. The most common causes of death were multiorgan failure (25.9%), hemorrhagic stroke (24.7%), and progressive heart failure (20.0%). Nearly half (45.6%) of patients saw palliative care in consultation within a month prior to death. However, only 13 (15.5%) patients enrolled in hospice a median of 11 (range 1-315) days prior to death, including 4 patients with concurrent cancer, 2 with stroke, and 7 with multiorgan failure. The vast majority of patients (78.6%) died in the hospital, and of those hospitalized at death, 87.7% died in the intensive care unit. Most patients hospitalized at death transitioned to a comfort-directed approach to care within 24 hours of dying. In total, 43 (48.3%) patients had their LVAD deactivated prior to death, with all but 3 undergoing deactivation in the hospital. The vast majority of patients died within an hour of LVAD deactivation, and all within 26 hours. Conclusions: In contrast to the general heart failure population, most patients with DT-LVAD die in the hospital and very few enroll in hospice. A significant body of research has demonstrated that patients who die in the intensive care unit and the hospital, as opposed to home or with hospice assistance, experience worse quality of life, quality of death and caregiver outcomes. Potential reasons that patients with DT-LVAD may experience different end-of-life care than other patients with heart failure exist, including that they often experience sudden changes in health status prior to death from acute events such as hemorrhagic stroke. However, further work is needed to understand these differences and to determine whether patients with DT-LVAD are receiving optimal end-of-life care.

Abstract Aims Circulating progenitor cells (CPCs) play a role in vascular repair and plaque stability, while osteocalcin (OC) expressing CPCs have been linked to unstable plaque and adverse cardiovascular outcomes. However, their role in cardiac allograft vasculopathy (CAV) has not been elucidated. This cohort study aimed to investigate the contribution of CPCs on CAV progression and cardiovascular events after heart transplantation. Methods and results A total of 80 heart transplant patients (mean age 55 ± 14 years, 72% male) undergoing annual intravascular ultrasound (IVUS) had fresh CPCs marked by CD34, CD133, and OC counted in peripheral blood using flow cytometry, on the same day as baseline IVUS. CAV progression was assessed by IVUS as the change (Δ) in plaque volume divided by segment length (PV/SL), adjusted for the time between IVUS measurements [median 3.0, interquartile range (2.8–3.1) years] and was defined as ΔPV/SL that is above the median ΔPV/SL of study population. Major adverse cardiac events (MACEs) were defined as any incident of revascularization, myocardial infarction, heart failure admission, re-transplantation, stroke, and death. Patients with higher CD34+CD133+ CPCs had a decreased risk of CAV progression [odds ratio 0.58, 95% confidence interval (CI) (0.37–0.92), P = 0.01] and MACE [hazard ratio (HR) 0.79, 95% CI (0.66–0.99), P = 0.05] during a median (interquartile range) follow-up of 8.0 years (7.2–8.3). Contrarily, higher OC+ cell counts were associated with an increased risk of MACE [HR 1.26, 95% CI (1.03–1.57), P = 0.02]. Conclusions Lower levels of CD34+CD133+ CPCs are associated with plaque progression and adverse long-term outcomes in patients who underwent allograft heart transplantation. In contrast, higher circulating OC+ levels are associated with adverse long-term outcomes. Thus, CPCs might play a role in amelioration of transplant vasculopathy, while OC expression by these cells might play a role in progression.