Aggressive steroid weaning after cardiac transplantation is possible without the additional risk of significant rejection

Immunosuppression and Heart Transplantation

Since the first human heart transplant in 1967, immense advancements have been made in the field of immunosuppression. This chapter provides an in-depth analysis of the use of immunosuppressive agents in heart transplant recipients. Evidence regarding maintenance immunosuppressive regimens, the efficacy of induction immunosuppression and corticosteroid weaning, as well as the use of distinct immunosuppression regimens within select patient populations is summarized. This chapter helps elucidate the data regarding contemporary protocols in cardiac transplantation.

Steroid withdrawal after heart transplantation in adults

Corticosteroids (CSs) are a key component of immunosuppressive treatment after heart transplantation (HTx). While effectively preventing acute rejection, several adverse effects including diabetes, hypertension, osteoporosis, and hyperlipidemia are associated with long-term use. As these complications may impair long-term outcome in HTx recipients, withdrawal of CSs is highly desirable, however, no uniform approach exists. Previous experience suggests that CS withdrawal can be accomplished without an increase in the incidence of acute rejection and even carrying a survival benefit. Also, common complications related to long-term CS use appear to be less frequent following CS discontinuation. Recipients who successfully discontinue CSs, however, likely belong to an immune-privileged subset of patients with low risk of post-transplant complications. Available studies evaluating CS withdrawal are highly heterogeneous and consensus on optimal timing and eligibility for withdrawal is lacking. Efforts to improve the understanding of optimal CS withdrawal strategy are of great importance in order to safely promote CS weaning in eligible patients and thereby alleviate the adverse effects of long-term CS use on post-transplant outcomes. The purpose of this review was to evaluate different protocols of CS withdrawal after HTx in terms of clinical outcomes and to explore criteria for successful CS withdrawal.

Impact of diabetes mellitus on clinical outcomes after heart transplantation

PURPOSE

Diabetes mellitus (DM) is common among recipients of heart transplantation (HTx) but its impact on clinical outcomes is unclear. We evaluated the associations between pretransplant DM and posttransplant DM (PTDM) and outcomes among adults receiving HTx at a single center.

METHODS

We performed a retrospective study (range 01/2008 - 07/2018), n = 244. The primary outcome was survival; secondary outcomes included acute rejection, cardiac allograft vasculopathy, infection requiring hospitalization, macrovascular events, and dialysis initiation post-transplant. Comparisons were performed using Kaplan-Meier and multivariable Cox regression analyses.

RESULTS

Pretransplant DM was present in 75 (30.7%) patients and was associated with a higher risk for infection requiring hospitalization (p<0.05), but not with survival or other outcomes. Among the 144 patients without pretransplant DM surviving to one year, 29 (20.1%) were diagnosed with PTDM at the 1-year follow-up. After multivariable adjustment, PTDM diagnosis at 1-year remained associated with worse subsequent survival (hazard ratio 2.72, 95% confidence interval 1.03-7.16). Predictors of PTDM at 1-year included cytomegalovirus seropositivity and higher prednisone dose (>5mg/day) at 1-year follow-up.

CONCLUSIONS

Compared to HTx recipients without baseline DM, those with baseline DM have a higher risk for infections requiring hospitalization, and those who develop DM after HTx have worse survival. This article is protected by copyright. All rights reserved.

Hurdles to Cardioprotection in the Critically Ill

Cardiovascular disease is the largest contributor to worldwide mortality, and the deleterious impact of heart failure (HF) is projected to grow exponentially in the future. As heart transplantation (HTx) is the only effective treatment for end-stage HF, development of mechanical circulatory support (MCS) technology has unveiled additional therapeutic options for refractory cardiac disease. Unfortunately, despite both MCS and HTx being quintessential treatments for significant cardiac impairment, associated morbidity and mortality remain high. MCS technology continues to evolve, but is associated with numerous disturbances to cardiac function (e.g., oxidative damage, arrhythmias). Following MCS intervention, HTx is frequently the destination option for survival of critically ill cardiac patients. While effective, donor hearts are scarce, thus limiting HTx to few qualifying patients, and HTx remains correlated with substantial post-HTx complications. While MCS and HTx are vital to survival of critically ill cardiac patients, cardioprotective strategies to improve outcomes from these treatments are highly desirable. Accordingly, this review summarizes the current status of MCS and HTx in the clinic, and the associated cardiac complications inherent to these treatments. Furthermore, we detail current research being undertaken to improve cardiac outcomes following MCS/HTx, and important considerations for reducing the significant morbidity and mortality associated with these necessary treatment strategies.

Infectious complications after heart transplantation in patients screened with gene expression profiling

BACKGROUND

The risk of infection after heart transplantation is highest within the first year and represents the leading cause of early mortality. In this cohort of patients enrolled in the Outcomes AlloMap Registry (OAR), we sought to describe infection episodes (IEp) resulting in hospitalization, in the early (<1 year) and late (≥1 year) post-transplant period and determine the impact of immunosuppression on incidence of infection.

METHODS

The primary aim was to assess the incidence and nature of IEp. The secondary aim was to evaluate the effect of potential risk factors, such as recipient age; sex; body mass index; panel-reactive antibodies; cytomegalovirus (CMV) primary mismatch; prednisone, tacrolimus, and sirolimus levels; and gene expression profile (GEP) score, in the development of IEp.

RESULTS

The OAR comprises 1,504 patients, of whom 220 patients (14.6%) had an IEp during a median follow-up period of 382 days (interquartile range [IQR] 230 to 579 days). The cause-specific 5-year hazard ratio for any infection was 2.029 (p = 0.12). The pattern of early infection was consistent with nosocomial and opportunistic causes, whereas later infection was consistent with late-onset opportunistic and community-acquired etiologies. Sixty-two percent of the infections occurred early. In the time-dependent analysis, higher prednisone dose (log prednisone, hazard ratio [HR] 1.30, p = 0.022) was the most significant risk factor for all IEp.

CONCLUSIONS

In the OAR cohort, the majority of infections occurred within 1 year after transplantation. Clinicians may consider more aggressive prednisone withdrawal in low-risk patients to reduce IEp.

Risk evaluation using gene expression screening to monitor for acute cellular rejection in heart transplant recipients

BACKGROUND

Gene expression profiling (GEP) was developed for non-invasive surveillance of acute cellular rejection. Despite its widespread use, there has been a paucity in outcome data for patients managed with GEP outside of clinical trials.

METHODS

The Outcomes AlloMap Registry (OAR) is an observational, prospective, multicenter study including patients aged ≥ 15 years and ≥ 55 days post-cardiac transplant. Primary outcome was death and a composite outcome of hemodynamically significant rejection, graft dysfunction, retransplantation, or death. Secondary outcomes included readmission rates and development of coronary allograft vasculopathy and malignancies.

RESULTS

The study included 1,504 patients, who were predominantly Caucasian (69%), male (74%), and aged 54.1 ± 12.9 years. The prevalence of moderate to severe acute cellular rejection (≥2R) was 2.0% from 2 to 6 months and 2.2% after 6 months. In the OAR there was no association between higher GEP scores and coronary allograft vasculopathy (p = 0.25), cancer (p = 0.16), or non-cytomegalovirus infection (p = 0.10). Survival at 1, 2, and 5 years post-transplant was 99%, 98%, and 94%, respectively. The composite outcome occurred in 103 patients during the follow-up period. GEP scores in dual-organ recipients (heart-kidney and heart-liver) were comparable to heart-alone recipients.

CONCLUSIONS

This registry comprises the largest contemporary cohort of patients undergoing GEP for surveillance. Among patients selected for GEP surveillance, survival is excellent, and rates of acute rejection, graft dysfunction, readmission, and death are low.

Racial and ethnic disparities in outcomes after heart transplantation: A systematic review of contributing factors and future directions to close the outcomes gap

The demographics of patients undergoing heart transplantation in the United States have shifted over the last 10 years, with an increasing number of racial and ethnic minorities undergoing heart transplant. Multiple studies have shown that survival of African American patients after heart transplantation is lower compared with other ethnic groups. We review the data supporting the presence of this outcome disparity and examine the multiple mechanisms that contribute. With an increasingly diverse population in the United States, knowledge of these disparities, their mechanisms, and ways to improve outcomes is essential.

Steroid-free and steroid withdrawal protocols in heart transplantation: the review of literature

Corticosteroids (CSs) are still the mainstay of induction, rescue, and maintenance in heart transplantation (HTx). However, their use is associated with significant and well-documented side effects usually related to the dose administered and the duration of therapy. Moreover, CSs interfere with the recipient's quality of life and with the active process of graft tolerance. Physicians have been exploring ways to avoid or reduce CSs in association with other immunosuppressive drugs, minimizing side effects and costs. The regimens are classified as steroid-free or steroid withdrawal protocols. The studies analyzed in this review come to similar conclusions as benefits and adverse consequences: steroid-free protocols should be advisable and mandatory in pediatric patients, insulin-dependent diabetes mellitus (IDDM), presence of infection, familial metabolic disorders/obesity, severe osteoporosis, and in the elderly. On the other hand, steroid withdrawal can be successfully achieved in 50-80%, with late better than early withdrawal, no increase in rejection-related mortality, no adverse impact on survival, and probably a better quality of live. Safety and efficacy can certainly be improved by an individualized approach to the transplant recipient.

Steroid withdrawal and reduction of cyclosporine A under mycophenolate mofetil after heart transplantation

Survival and quality of life after heart transplantation are limited by a significant incidence of cardiovascular complications. Side effects of immunosuppressives contribute unfavorably. Aim of this study was to determine (1) whether withdrawal of corticosteroids and dose reduction of cyclosporine A can be performed safely under immunosuppressive therapy with mycophenolate mofetil and (2) if this is beneficial for renal function and cardiovascular risk reduction. Long term heart transplant recipients on steroids and cyclosporine A were examined in a monocentric, prospective, single-arm cohort study. Steroids were withdrawn, mycophenolate mofetil introduced and cyclosporine A dose reduced (target level 50-90 ng/ml). Follow up was 24 months. 23 patients were analyzed: Renal parameters (creatinine, urea, uric acid) improved significantly (p<0.01), as did cardiovascular parameters (heart rate [p<0.05], systolic and diastolic blood pressure [p<0.01]), HbA1c (p<0.05) and triglycerides (p<0.05). In contrast, the self-percepted state of health (SF36™) decreased. Drop outs occurred mostly due to steroid withdrawal syndrome [n=7]. The incidence of adverse events reflected the usual course after heart transplantation. We conclude that CS free immunosuppression comprising reduced cyclosporine levels and addition of MMF in long term heart transplant recipients is safe and improves the cardiovascular risk profile, carbohydrate metabolism and renal function.

Postoperative care of the transplanted patient

The successful delivery of optimal peri-operative care to pediatric heart transplant recipients is a vital determinant of their overall outcomes. The practitioner caring for these patients must be familiar with and treat multiple simultaneous issues in a patient who may have been critically ill preoperatively. In addition to the complexities involved in treating any child following cardiac surgery, caretakers of newly transplanted patients encounter multiple transplant-specific issues. This chapter details peri-operative management strategies, frequently encountered early morbidities, initiation of immunosuppression including induction, and short-term outcomes.

Invasive aspergillosis among heart transplant recipients is rare but causes rapid death due to septic shock and multiple organ dysfunction syndrome

Between 2000 and 2011, proven or probable invasive aspergillosis (IA) was diagnosed in 1.7% (8/455) of heart transplant (HTx) recipients at our center, in the absence of antifungal prophylaxis. All patients had invasive pulmonary infections and 75% (6/8) were diagnosed during 2 separate 3-month periods. Cases were notable for their association with septic shock and multiple organ dysfunction syndrome (MODS) (75%, 6/8 each), non-specific clinical and radiographic findings, and rapid mortality despite mould-active antifungal therapy (88%, 7/8; occuring at a median 11 days after diagnosis). All patients had predisposing conditions known to be risk factors for IA. For patients with early IA (within 90 days of HTx), conditions included hemodialysis, thoracic re-operation, and the presence of another case in the institution within the preceding 3 months. For late-onset IA, conditions included hemodialysis and receipt of augmented immunosuppression. Clinicians should suspect IA in HTx recipients with risk factors who present with non-specific and unexplained respiratory syndromes, including those in septic shock and MODS, and institute prompt antifungal therapy without waiting for the results of cultures or other diagnostic tests.

Quest for lower immunosuppression in cardiac transplantation: an analysis of the TICTAC trial

Evaluation of: Baran DA, Zucker MJ, Arroyo LH et al.: A prospective, randomized trial of single versus dual drug immunosuppression in heart transplantation: the Tacrolimus in Combination, Tacrolimus Alone Compared (TICTAC) trial. Circ. Heart Fail. 4(2), 129–137 (2011). Success in cardiac transplantation has been attributed to improved immunosuppressive regimens. Conventionally, patients are treated with a triple regimen following transplantation, consisting of a calcineurin inhibitor (cyclosporine or tacrolimus), antiproliferative agent (mycophenolate mofetil) and corticosteroids. These agents, however, are associated with a significant morbidity which has prompted a quest for minimization of immunosuppressive regimens; a challenging goal, given the potential for allograft rejection particularly early after transplantation. This article reviews a recent study by Baran and colleagues who boldly challenged the notion that triple immunosuppression is a prerequisite for success after cardiac transplantation. The authors successfully demonstrate the feasibility of weaning corticosteroids and mycophenolate mofetil early after cardiac transplantation, maintaining patients solely on monotherapy with tacrolimus. This evaluation focuses on the findings and limitations of the study and provides the historical background which led to this promising clinical trial.

Changing trends in infectious disease in heart transplantation

BACKGROUND

During the past 25 years, advances in immunosuppression and the use of selective anti-microbial prophylaxis have progressively reduced the risk of infection after heart transplantation. This study presents a historical perspective of the changing trends of infectious disease after heart transplantation.

METHODS

Infectious complications in 4 representative eras of immunosuppression and anti-microbial prophylaxis were analyzed: (1) 38 in the pre-cyclosporine era (1978-1980), (2) 72 in the early cyclosporine era (1982-1984), where maintenance immunosuppression included high-dose cyclosporine and corticosteroid therapy; (3) 395 in the cyclosporine era (1988-1997), where maintenance immunosuppression included cyclosporine, azathioprine, and lower corticosteroid doses; and (4) 167 in the more recent era (2002-2005), where maintenance immunosuppression included cyclosporine and mycophenolate mofetil.

RESULTS

The overall incidence of infections decreased in the 4 cohorts from 3.35 episodes/patient to 2.03, 1.35, and 0.60 in the more recent cohorts (p < 0.001). Gram-positive bacteria are emerging as the predominant cause of bacterial infections (28.6%, 31.4%, 51.0%, 67.6%, p = 0.001). Cytomegalovirus infections have significantly decreased in incidence and occur later after transplantation (88 +/- 77 days, pre-cyclosporine era; 304 +/- 238 days, recent cohort; p < 0.001). Fungal infections also decreased, from an incidence of 0.29/patient in the pre-cyclosporine era to 0.08 in the most recent era. A major decrease in Pneumocystis jiroveci and Nocardia infections has also occurred.

CONCLUSIONS

The overall incidence and mortality associated with infections continues to decrease in heart transplantation and coincides with advances in immunosuppression, the use of selective anti-microbial prophylaxis, and more effective treatment regimens.