Randomized controlled trial of sirolimus conversion in cardiac transplant recipients with renal insufficiency

A quantitative assessment of renal function utilizing albuminuria in pediatric heart transplant recipients

INTRODUCTION

Kidney disease is common after pediatric heart transplantation. Serum creatinine-based glomerular filtration rate is the most frequently reported measure of kidney function. Albuminuria is an additional marker of kidney dysfunction and is not well described in this population. In this study, we evaluate the prevalence and degree of albuminuria and describe clinical factors associated with albuminuria in a cohort of pediatric heart transplant recipients.

METHODS

This was a cross-sectional study of pediatric heart transplant recipients. Albuminuria was assessed using spot urine albumin-to-creatinine ratio collected at the most recent annual screening cardiac catheterization through August 2019.

RESULTS

In 115 patients at a median duration of 10.2 years post-transplant, 39% had albuminuria. Stage 3 or greater chronic kidney disease was present in 6%. The immunosuppressive regimen at the time of measurement contained a calcineurin inhibitor (CNI) in 88% and a proliferation signal inhibitor (PSI) in 62%. In multivariable modeling, lower eGFR, PSI use, and younger age at transplant were associated with higher levels of albuminuria, whereas CNI use was associated with lower levels of albuminuria.

CONCLUSION

Albuminuria is a prevalent finding in medium-term follow up of pediatric heart transplant recipients, reflecting kidney injury, and is associated with other markers of kidney dysfunction, such as low eGFR. Younger age at transplant, lower eGFR, and PSI use were among the associations with albuminuria.

Sirolimus potentiated angioedema: A case report and review of the literature

Introduction

In the realm of organ transplantation, particularly heart transplantation, angioedema presents a significant challenge. This clinical condition ranges from minor facial edema to life-threatening swelling of vital structures. Its multifactorial etiology involves various factors and mechanisms, including C1 esterase inhibitor deficiency, food allergen hypersensitivity, and adverse drug reactions, notably involving angiotensin-converting enzyme (ACE) inhibitors and mechanistic target of rapamycin inhibitors (mTOR-Is). We present a rare case of sirolimus potentiated angioedema in a patient with long-standing ACE inhibitor therapy.

Case

A 52-year-old male with a history of heart transplant developed severe upper and lower lip edema. The patient had been on Lisinopril without any adverse events. However, sirolimus was recently added to his drug regimen. Sirolimus potentiated angioedema was suspected.

Intervention

Intravenous methylprednisolone, famotidine, and diphenhydramine were initiated, and both lisinopril and sirolimus were discontinued. The patient showed improvement and was discharged with oral antihistamines.

Lessons

Transplant physicians should be aware of the life-threatening interaction between ACE inhibitors and mTOR-Is like sirolimus. Consideration should be given to switching from an ACE inhibitor to an angiotensin-receptor blocker when initiating patients on mTOR-Is.

Prevalence and clinical characteristics of oral lesions in heart transplant patients induced by sirolimus and everolimus: a systematic review and meta-analysis on a global scale

OBJECTIVE

Sirolimus (SRL) and everolimus (EVL) are increasingly included in immunosuppressive protocols after heart transplantation. They present some side effects, including the appearance of painful lesions in the oral cavity. Therefore, this systematic review aimed to verify the global prevalence and clinical characteristics of oral lesions induced by SRL and EVL in heart transplant patients.

STUDY DESIGN

A systematic review was performed using 5 main electronic databases (Medline/PubMed, SCOPUS, EMBASE, Web of Science, and LILACS), in addition to the gray literature. Studies were independently assessed by 2 reviewers based on established eligibility criteria. The risk of bias was assessed using the Joanna Briggs Institute appraisal tools, and the certainty of evidence was evaluated through GRADE assessment.

RESULTS

Seventeen studies (860 patients) were included in the qualitative analysis. Of these, 11 studies were pooled in a meta-analysis of prevalence. The worldwide prevalence of oral lesions induced by SRL and EVL in heart transplant patients was 10.0%, and most lesions were described as ulcers >1.0 cm, related to significant pain.

CONCLUSIONS

Oral lesions induced by SRL and/or EVL, although not very prevalent, have a relevant impact on patient's lives and the continuity of treatment.

Maintenance immunosuppression in heart transplantation: insights from network meta-analysis of various immunosuppression regimens

Previous studies have reported superiority of mechanistic target-of-rapamycin (mTOR) antagonists (mTA) over calcineurin inhibitors (CNI) as part of maintenance immunosuppression (IS) in mitigating cardiac allograft vasculopathy (CAV) after heart transplantation (HT). MEDLINE and EMBASE were searched through October 2019 for studies comparing maintenance IS with mTA + antimetabolites (AM), CNI + mTA or CNI + AM post HT. The main outcomes were all-cause mortality, CAV, acute rejection, CMV infections, and change in eGFR. To compare different IS antagonists, a random-effects network meta-analysis was performed. We used p-scores to rank best treatments per outcome. Our search identified fifteen eligible studies (5 studies comparing mTA + AM vs. CNI + AM, 9 comparing CNI + mTA vs. CNI + AM, 1 comparing mTA + AM vs. CNI + mTA, 8 using everolimus and 7 sirolimus as mTA) reporting the selected outcomes. We did not identify any statistical difference in all-cause mortality among the three IS regimens without heterogeneity among studies. CAV rates were significantly lower with CNI + mTA (odds ratio [OR] 0.53, 95% confidence interval [CI] 0.3-0.92). Acute rejection rates were significantly lower with CNI + AM (OR 0.26, 95% CI 0.12-0.56) and with CNI + mTA (OR 0.16, 95% CI 0.07-0.33) compared with mTA + AM without significant heterogeneity (I² = 43%, p = 0.9). CMV infections were significantly lower with mTA + AM (OR 0.13, 95% CI 0.03-0.46) and with CNI + mTA (OR 0.27, 95% CI 0.2-0.38) compared with CNI + AM without heterogeneity. mTA + AM led to higher eGFR compared with CNI + AM (9.06 ml/min/1.73 m2, 95% CI 3.15-14.97) and CNI + Mta (9.64 ml/min/1.73 m2, 95% CI 0.91-18.36), but the heterogeneity among studies was significant. CNI + mTA ranked better for CAV (p = 0.78), and acute rejection (p = 0.99) while mTA + AM for CMV infection (p = 0.94) and improvement in renal function (p = 0.93) than other regimens. Different IS regimens have similar effects on survival post HT, but CNI + mTA was associated with lower CAV rates, and acute rejection, while mTA + AM with less CMV infection post HT.

Sirolimus-Based Immunosuppression Is Associated with Decreased Incidence of Post-Transplant Lymphoproliferative Disorder after Heart Transplantation: A Double-Center Study

Mammalian target of rapamycin (mTOR) inhibitors have been shown to reduce proliferation of lymphoid cells; thus, their use for immunosuppression after heart transplantation (HT) may reduce post-transplant lymphoproliferative disorder (PTLD) risk. This study sought to investigate whether the sirolimus (SRL)-based immunosuppression regimen is associated with a decreased risk of PTLD compared with the calcineurin inhibitor (CNI)-based regimen in HT recipients. We retrospectively analyzed 590 patients who received HTs at two large institutions between 1 June 1988 and 31 December 2014. Cox proportional-hazard modeling was used to examine the association between type of primary immunosuppression and PTLD after adjustment for potential confounders, including Epstein-Barr virus (EBV) status, type of induction therapy, and rejection. Conversion from CNI to SRL as primary immunosuppression occurred in 249 patients (42.2%). During a median follow-up of 6.3 years, 30 patients developed PTLD (5.1%). In a univariate analysis, EBV mismatch was strongly associated with increased risk of PTLD (HR 10.0, 95% CI: 3.8-26.6; p < 0.001), and conversion to SRL was found to be protective against development of PTLD (HR 0.19, 95% CI: 0.04-0.80; p = 0.02). In a multivariable model and after adjusting for EBV mismatch, conversion to SRL remained protective against risk of PTLD compared with continued CNI use (HR 0.12, 95% CI: 0.03-0.55; p = 0.006). In conclusion, SRL-based immunosuppression is associated with lower incidence of PTLD after HT. These findings provide evidence of a benefit from conversion to SRL as maintenance therapy for mitigating the risk of PTLD, particularly among patients at high PTLD risk.

Novel Immunosuppression in Solid Organ Transplantation

Solid organ transplantation and survival has improved tremendously in the last few decades, much of the success has been attributed to the advancements in immunosuppression. While steroids are being replaced and much of the immunosuppressive strategies focus on steroid free regimens, novel agents have introduced in the induction, maintenance, and treatment of acute rejection phase. MTOR inhibitors have helped with the renal sparing side effect from the calcineurin inhibitors, newer agents such as rituximab have decreased the incidence of donor-specific antibodies which led to decreased incidence of acute rejection reactions. In this chapter we discuss the newer therapies directed specifically for solid organ transplantation.

CKD in Recipients of Nonkidney Solid Organ Transplants: A Review

Chronic kidney disease (CKD) after solid organ transplant is a common clinical presentation, affecting 10% to 20% of liver, heart and lung transplant recipients and accounting for approximately 5% of the kidney transplant waiting list. The causes of CKD are different for different types of transplants and are not all, or even predominantly, due to calcineurin inhibitor toxicity, with significant heterogeneity particularly in liver transplant recipients. Many solid organ transplant recipients with advanced CKD benefit from kidney transplantation, but have a higher rate of death while waitlisted and higher mortality following transplant than the general kidney failure population. Recent organ allocation policies and proposals have attempted to address the appropriate identification and prioritization of candidates in need of a kidney transplant, either simultaneous with or following non-kidney transplant. Future research should focus on predictive factors for individuals identified at high risk for progression to kidney failure and death, and strategies to preserve kidney function and minimize the CKD burden in this unique patient population.

Mammalian Target of Rapamycin Inhibitors Vs Calcineurin Inhibitors in Chronic Graft Rejection After Lung Transplantation: A Systematic Review and Meta-Analysis

BACKGROUND

The number of lung transplantations has been rising constantly. However, use of this therapeutic resource is limited by several issues that are difficult to resolve, such as chronic graft rejection and complications secondary to immunosuppression.

METHODS

This systematic review compared mammalian target of rapamycin (mTOR) inhibitor immunosuppression associated with low-dose calcineurin inhibitors with isolated calcineurin inhibitor immunosuppression on the new-onset chronic rejection development and mortality 12 months after lung transplantation. Three controlled randomized clinical trials (SHITRIT, NOCTET, and 4EVERLUNG) were selected from electronic databases.

RESULTS

Meta-analysis of the data at 12 months postintervention showed that only 4EVERLUNG assessed chronic graft rejection, with a higher incidence in the control group; however, the difference was not statistically significant (P = .197). Significant data were related to an increase in the number of adverse events (P = .0064) and improved renal function (P < .0001) in the mTOR inhibitor-based scheme. The other outcomes indicated a trend toward greater risk of death and acute graft rejection with the use of mTORs.

CONCLUSIONS

The researchers suggest considering the use of mTOR inhibitors, whose greatest benefit is felt by patients with renal dysfunction, in association with the use of calcineurin inhibitors, because of the imminent risk of death among patients with renal failure.

Effects of mTOR inhibitor-related proteinuria on progression of cardiac allograft vasculopathy and outcomes among heart transplant recipients

We have previously described the use of sirolimus (SRL) as primary immunosuppression following heart transplantation (HT). The advantages of this approach include attenuation of cardiac allograft vasculopathy (CAV), improvement in glomerular filtration rate (GFR), and reduced malignancy. However, in some patients SRL may cause significant proteinuria. We sought to investigate the prognostic value of proteinuria after conversion to SRL. CAV progression and adverse clinical events were studied. CAV progression was assessed by measuring the Δ change in plaque volume (PV) and plaque index (PI) per year using coronary intravascular ultrasound. Proteinuria was defined as Δ urine protein ≥300 mg/24 h at 1 year after conversion to SRL. Overall, 137 patients were analyzed (26% with proteinuria). Patients with proteinuria had significantly lower GFR (P = .005) but similar GFR during follow-up. Delta PV (P < .001) and Δ PI (P = .001) were significantly higher among patients with proteinuria after adjustment for baseline characteristics. Multivariate Cox regression analysis showed higher all-cause mortality (hazard ratio 3.8; P = .01) with proteinuria but similar risk of CAV-related events (P = .61). Our results indicate that proteinuria is a marker of baseline renal dysfunction, and that HT recipients who develop proteinuria after conversion to SRL have less attenuation of CAV progression and higher mortality risk.

Canadian Cardiovascular Society/Canadian Cardiac Transplant Network Position Statement on Heart Transplantation: Patient Eligibility, Selection, and Post-Transplantation Care

Significant practice-changing developments have occurred in the care of heart transplantation candidates and recipients over the past decade. This Canadian Cardiovascular Society/Canadian Cardiac Transplant Network Position Statement provides evidence-based, expert panel recommendations with values and preferences, and practical tips on: (1) patient selection criteria; (2) selected patient populations; and (3) post transplantation surveillance. The recommendations were developed through systematic review of the literature and using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. The evolving areas of importance addressed include transplant recipient age, frailty assessment, pulmonary hypertension evaluation, cannabis use, combined heart and other solid organ transplantation, adult congenital heart disease, cardiac amyloidosis, high sensitization, and post-transplantation management of antibodies to human leukocyte antigen, rejection, cardiac allograft vasculopathy, and long-term noncardiac care. Attention is also given to Canadian-specific management strategies including the prioritization of highly sensitized transplant candidates (status 4S) and heart organ allocation algorithms. The focus topics in this position statement highlight the increased complexity of patients who undergo evaluation for heart transplantation as well as improved patient selection, and advances in post-transplantation management and surveillance that have led to better long-term outcomes for heart transplant recipients.

Interventions to Prevent Nonmelanoma Skin Cancers in Recipients of a Solid Organ Transplant: Systematic Review of Randomized Controlled Trials

BACKGROUND

Organ transplant recipients are at high risk of developing skin cancer. The benefits and harms of interventions to prevent nonmelanoma skin cancer in solid organ transplant recipients have not been summarized.

METHODS

We searched MEDLINE, Embase, and CENTRAL through April 2018. Risk of bias was assessed using the Cochrane tool, and evidence certainty was evaluated using the Grades of Recommendation, Assessment, Development, and Evaluation process. Prespecified outcomes were nonmelanoma skin cancer, clearance and prevention of keratotic skin lesions, and intervention-specific adverse events.

RESULTS

Ninety-two trials (20 012 participants) were included. The evaluated treatments were cancer-specific interventions (acitretin, imiquimod, photodynamic therapy, nicotinamide, topical diclofenac, and selenium) and immunosuppression regimes (azathioprine, mycophenolate mofetil, calcineurin inhibitors, mammalian target of rapamycin [mTOR] inhibitors, belatacept, induction agents, and withdrawal of calcineurin inhibitors or corticosteroids). Effects on nonmelanoma skin cancer were uncertain for photodynamic therapy (3 trials, 93 participants, risk ratio [RR] 1.42 [95% confidence interval (CI), 0.65-3.11]; low certainty evidence), nicotinamide (2 trials, 60 participants), acitretin (2 trials, 61 participants), and imiquimod (1 trial, 20 participants) compared to control. mTOR inhibitors probably reduced skin cancer compared to calcineurin inhibitors (12 trials, 2225 participants, RR 0.62 [95% CI, 0.45-0.85]; moderate certainty evidence). Photodynamic therapy may cause pain at the treatment site (4 trials, 95 patients, RR 17.09 [95% CI, 4.22-69.26]; low certainty evidence).

CONCLUSIONS

There is limited evidence for the efficacy and safety of specific treatments to prevent nonmelanoma skin cancers among solid organ transplant recipients.

Invasive haemodynamics in de novo everolimus vs. calcineurin inhibitor heart transplant recipients

Aims

Invasive haemodynamic profiles at rest and during exercise after heart transplantation (HTx) have never been described in a randomized trial where de novo everolimus (EVR)‐based therapy with early calcineurin inhibitor (CNI) withdrawal has been compared with conventional CNI treatment. We report central invasive haemodynamic parameters at rest and exercise during a 3 year follow‐up after HTx in a sub‐study of the SCandiavian Heart transplant Everolimus De novo stUdy with earLy calcineurin inhibitor avoidancE trial. We hypothesized that the nephroprotective properties, the less development of cardiac allograft vasculopathy (CAV), and the antifibrotic properties of EVR, in comparison with CNI‐based immunosuppression, would demonstrate favourable invasive haemodynamic profiles in patients at rest and during exercise.

Methods and results

Ninety of 115 HTx recipients randomized to EVR or CNI treatment performed right heart catheterization at rest and 68 performed right heart catheterization at exercise up to 3 years after HTx. Haemodynamic profiles were compared between EVR and CNI treatment groups. Resting haemodynamics improved in both groups from pre‐HTx to the first follow‐up at 7–11 weeks post‐HTx and thereafter remained unchanged up to 3 years of follow‐up. During follow‐up, cardiac reserve during exercise increased with higher levels of maximum heart rate (118 to 148 b.p.m., P < 0.001), mean arterial pressure (103 to 128 mmHg, P < 0.001), and cardiac output (10.3 to 12.2 l/min, P < 0.001). No significant differences in haemodynamic parameters were observed between the EVR and CNI groups at rest or exercise. Isolated post‐capillary pulmonary hypertension (mean pulmonary arterial pressure > 20 mmHg, pulmonary arterial wedge pressure ≥ 15 mmHg, and pulmonary vascular resistance <3) were measured in 11% of the patients at 7–11 weeks, 5% at 12 months, and 6% at 36 months after HTx. The EVR group had significantly better kidney function (76 mL/min/1 vs. 60 mL/min/1, P < 0.001) and reduced CAV (P < 0.01) but an increased rate of early biopsy‐proven treated rejections (21.2% vs 5.7%, P < 0.01) compared with the CNI group at any time point. The differences in renal function, CAV, or early biopsy‐proven treated acute rejections were not associated with altered haemodynamics.

Conclusions

De novo EVR treatment with early CNI withdrawal compared with conventional CNI therapy did not result in differences in haemodynamics at rest or during exercise up to 3 years after HTx despite significant differences in renal function, reduced CAV, and number of early biopsy‐proven treated rejections.

Long-Term Sirolimus for Primary Immunosuppression in Heart Transplant Recipients

BACKGROUND

Small studies have reported superiority of sirolimus (SRL) over calcineurin inhibitor (CNI) in mitigating cardiac allograft vasculopathy (CAV) after heart transplantation (HT). However, data on the long-term effect on CAV progression and clinical outcomes are lacking.

OBJECTIVES

The aim of this study was to test the long-term safety and efficacy of conversion from CNI to SRL as maintenance therapy on CAV progression and outcomes after HT.

METHODS

A cohort of 402 patients who underwent HT and were either treated with CNI alone (n = 134) or converted from CNI to SRL (n = 268) as primary immunosuppression was analyzed. CAV progression was assessed using serial coronary intravascular ultrasound during treatment with CNI (n = 99) and after conversion to SRL (n = 235) in patients who underwent at least 2 intravascular ultrasound studies.

RESULTS

The progression in plaque volume (2.8 ± 2.3 mm³/mm vs. 0.46 ± 1.8 mm³/mm; p < 0.0001) and plaque index (plaque volume-to-vessel volume ratio) (12.2 ± 9.6% vs. 1.1 ± 7.9%; p < 0.0001) were significantly attenuated when treated with SRL compared with CNI. Over a mean follow-up period of 8.9 years from time of HT, all-cause mortality occurred in 25.6% of the patients and was lower during treatment with SRL compared with CNI (adjusted hazard ratio: 0.47; 95% confidence interval: 0.31 to 0.70; p = 0.0002), and CAV-related events were also less frequent during treatment with SRL (adjusted hazard ratio: 0.35; 95% confidence interval: 0.21 to 0.59; p < 0.0001). Further analyses suggested more attenuation of CAV and more favorable clinical outcomes with earlier conversion to SRL (≤2 years) compared with late conversion (>2 years) after HT.

CONCLUSIONS

Early conversion to SRL is associated with attenuated CAV progression and with lower long-term mortality and fewer CAV-related events compared with continued CNI use.

mTOR Inhibition and Clinical Transplantation: Heart

This brief overview discusses recent data on the use of mammalian target of rapamycin (mTOR) inhibitors in heart transplantation. Trials on de novo use have shown good efficacy of mTOR inhibitors; however, adverse events are often seen. Conversion protocols in long-term patients are mainly used in patients with renal insufficiency. Calcineurin inhibitor minimization and conversion to calcineurin inhibitor-free protocols have proven to stabilize renal function in recent trials. Lastly, beneficial effects of mTORs against the development of graft vasculopathy, cytomeglovirus infection and malignancy have been shown. Nevertheless, lower tolerability of the drug has affected the long-term use in patients. Future consideration of using mTORs will be individualized protocols in special subpopulation after heart transplantation.

Outcomes associated with mammalian target of rapamycin (mTOR) inhibitors in heart transplant recipients: A meta-analysis

BACKGROUND

Data evaluating mTOR inhibitor use heart transplant (HT) patients comes from relatively small studies and controversy exists regarding their specific role. We performed a meta-analysis of randomized trials to evaluate the efficacy and safety of mTOR inhibitors in HT patients.

METHODS

We performed a systematic literature search of Medline and Embase through July 2017 identifying studies evaluating mTOR inhibitors in HT patients reporting effects on coronary allograft vasculopathy (CAV), renal function, acute cellular rejection (ACR), cytomegalovirus (CMV) infection, and discontinuation due to adverse drug events (ADE). Data were pooled using a random-effects model producing a mean difference (MD; for continuous data) or odds ratio (OR; for dichotomous data) and 95% confidence interval (CI).

RESULTS

14 trials reported at least one outcome of interest. Change in mean maximal intimal thickness was significantly reduced with mTOR (-0.04 [-0.07 to -0.02]) compared to calcineurin inhibitor/mycophenolate mofetil (CNI/MMF). Rates of CMV infection were also significantly reduced (0.26; [0.2 to 0.32]) with mTOR regimens compared to CNI/MMF therapy. ACR was more frequent with CNI-sparing regimens 6.46 [1.55 to 26.95]). eGFR was significantly improved with CNI-sparing therapies (mean difference 12.09 mL/min [2.43 to 21.74]), but was similar between CNI/mTOR versus CNI/MMF regimens (p > 0.05). Rates of discontinuation due to ADE were higher in mTOR-containing regimens (OR 2.15 [1.28 to 3.60], p = 0.01), while mortality rates were similar (OR 0.91 [0.61 to 1.37], p = 0.62).

CONCLUSIONS

mTOR-containing regimens can attenuate CAV and CMV risk in HT recipients. A mTOR/MMF combination preserves renal function but increases the risk of ACR.

Rapamycin Treatment Attenuates Angiotensin II -induced Abdominal Aortic Aneurysm Formation via VSMC Phenotypic Modulation and Down-regulation of ERK1/2 Activity

The aim of the present study is to address the effect of rapamycin on abdominal aortic aneurysm (AAA) and the potential mechanisms. A clinically relevant AAA model was induced in apolipoprotein E-deficient (ApoE-/-) mice, in which miniosmotic pump was implanted subcutaneously to deliver angiotensin II (Ang II) for 14 days. Male ApoE-/- mice were randomly divided into 3 groups: saline infusion, Ang II infusion, and Ang II infusion plus intraperitoneal injection of rapamycin. The diameter of the supra-renal abdominal aorta was measured by ultrasonography at the end of the infusion. Then aortic tissue was excised and examined by Western blotting and histoimmunochemistry. Ang n with or without rapamycin treatment was applied to the cultured vascular smooth muscle cells (VSMCs) in vitro. The results revealed that rapamycin treatment significantly attenuated the incidence of Ang II induced-AAA in ApoE-/- mice. Histologic analysis showed that rapamycin treatment decreased disarray of elastin fibers and VSMCs hyperplasia in the medial layer. Immunochemistry staining and Western blotting documented the increased phospho-ERK1/2 and ERK1/2 expression in aortic walls in Ang II induced-AAA, as well as in human lesions. Whereas in the rapamycintreated group, decreased phospho-ERKl/2 expression level was detected. Moreover, rapamycin reversed Ang II -induced VSMCs phenotypic change both in vivo and in vitro. Based on those results, we confirmed that rapamycin therapy suppressed Ang II -induced AAA formation in mice, partially via VSMCs phenotypic modulation and down-regulation of ERK1/2 activity.

Evaluation of a Heart Transplant Candidate

PURPOSE OF REVIEW

Heart transplantation is the best option for irreversible and critically advanced heart failure. However, limited donor pool, the risk of rejection, infection, and right ventricular dysfunction in short-term post-transplant period, as well as, the development of coronary allograft vasculopathy and malignancy in the long-term post-transplant period limits the utility of heart transplantation for all comers with advanced heart failure. Therefore, selection of appropriate candidates is very important for the best short and long-term prognosis. In this article, we discuss the principles of selection of candidates and compare to the recently updated International Society for Heart and Lung Transplantation (ISHLT) listing criteria with the goal of updating current clinical practice.

RECENT FINDINGS

We found that while most of the recommendations in the new listing criteria are continuous with the previous criteria, updated recommendations are made on the risk stratification models in choosing transplantation candidates. Recommendation on hepatic dysfunction is not directly included in the updated ISHLT listing criteria; however, adoption of the Model for End-stage Liver Disease (MELD) score and modified MELD scores in the evaluation of risk are suggested in recent studies. In conclusion, evaluation of patient selection for heart transplantation should be comprehensive and individualized with respect to indications and the risk of comorbidities of candidates. With the advancement of mechanical circulatory support (MCS), the selection of heart transplantation candidate is continuously evolving and widened. MCS as bridge to candidacy should be considered when the candidate has potentially reversible risk factors for transplantation.

Renal Allograft Outcome After Simultaneous Heart and Kidney Transplantation

Chronic kidney disease frequently accompanies end-stage heart failure and may result in consideration of simultaneous heart and kidney transplantation (SHKT). In recent years, there has been a significant increase in SHKT. This single-center cohort consisted of 35 patients who underwent SHKT during 1996 to 2015. The aim of this study was to review factors that may predict better long-term outcome after SKHT. Thirteen patients (37%) had delayed graft function (DGF) after transplant (defined as the need for dialysis during the first 7 days after transplant), which was significantly associated with mechanical circulatory support device therapy and high right ventricular systolic pressure before transplant. Most of the recipients had glomerular filtration rate (GFR) ≥50 ml/min/1.73 m² at 1 and 3 years after transplant (21 of 26 [81%] and 20 of 21 [95%], respectively). Higher donor age was associated with reduced 1-year GFR (p = 0.017), and higher recipient pretransplant body mass index was associated with reduced 3-year GFR (p = 0.008). There was a significant association between DGF and reduced median GFR at 1 and 3 years after transplant (p <0.005). Patient survival rates at 6 months, 1, and 3 years after transplant were 97%, 91%, and 86% respectively. In conclusions, our data support good outcomes after SHKT. Mechanical circulatory support device therapy and pulmonary hypertension before transplant are associated with DGF, which is a risk factor for poor long-term renal allograft function.

The CECARI Study: Everolimus (Certican®) Initiation and Calcineurin Inhibitor Withdrawal in Maintenance Heart Transplant Recipients with Renal Insufficiency: A Multicenter, Randomized Trial

In this 3-year, open-label, multicenter study, 57 maintenance heart transplant recipients (>1 year after transplant) with renal insufficiency (eGFR 30–60 mL/min/1.73 m²) were randomized to start everolimus with CNI withdrawal (N = 29) or continue their current CNI-based immunosuppression (N = 28). The primary endpoint, change in measured glomerular filtration rate (mGFR) from baseline to year 3, did not differ significantly between both groups (+7.0 mL/min in the everolimus group versus +1.9 mL/min in the CNI group, p = 0.18). In the on-treatment analysis, the difference did reach statistical significance (+9.4 mL/min in the everolimus group versus +1.9 mL/min in the CNI group, p = 0.047). The composite safety endpoint of all-cause mortality, major adverse cardiovascular events, or treated acute rejection was not different between groups. Nonfatal adverse events occurred in 96.6% of patients in the everolimus group and 57.1% in the CNI group (p < 0.001). Ten patients (34.5%) in the everolimus group discontinued the study drug during follow-up due to adverse events. The poor adherence to the everolimus therapy might have masked a potential benefit of CNI withdrawal on renal function.

Use of sirolimus in pediatric heart transplant patients: A multi-institutional study from the Pediatric Heart Transplant Study Group

BACKGROUND

Proliferation signal inhibitors, such as sirolimus, are increasingly used in solid-organ transplantation. However, limited data exist on sirolimus-treated pediatric patients. We aimed to describe sirolimus use in pediatric heart transplant patients and test the hypothesis that sirolimus use is associated with improved outcomes.

METHODS

A retrospective review and propensity-matched analysis of the Pediatric Heart Transplant Study database was performed on patients undergoing primary heart transplantation from 2004 to 2013 with at least 1 year of follow-up comparing patients treated vs not treated with sirolimus at 1 year after transplant. The primary outcome of interest was patient survival, with secondary outcomes including cardiac allograft vasculopathy, rejection, malignancy, and renal insufficiency.

RESULTS

Between 2004 and 2013, 2,531 patients underwent transplantation. At least 1 year of follow-up was available for 2,080 patients, of whom 144 (7%) were on sirolimus at 1 year post-transplant. Sirolimus-treated and non-treated patients had similar survival in the overall cohorts and in the propensity-matched analysis. The secondary outcomes measures were also similar, including a composite end point of all outcome measures. There was a trend toward increased time to cardiac allograft vasculopathy (p = 0.09) and decreased time to infection (p = 0.05) among sirolimus-treated patients in the overall cohort (p = 0.19) but not in the propensity-matched cohort (p = 0.17).

CONCLUSIONS

Sirolimus was used in less than 10% of patients at 1 year post-transplant. Overall outcomes of sirolimus treated and non-treated patients were similar with respect to survival and major transplant adverse events. Further study of sirolimus in pediatric heart transplant patients is needed.

Kidney transplantation as a therapeutic option for end-stage renal disease developing after heart transplantation

BACKGROUND

Progressive renal failure is a frequent complication after heart transplantation (HTx). It may result in end-stage renal disease (ESRD), prompting consideration of kidney Tx after HTx (KAH).

METHODS

We performed a retrospective single-center study of 268 HTx recipients to evaluate outcomes after KAH compared with HTx recipients with and without ESRD.

RESULTS

During a median follow-up of 76 months, ESRD developed in 51 patients (19), and 39 of them (76%) underwent KAH. The mean time from HTx to ESRD was 83 months. The incidence of switching to a calcineurin inhibitor (CNI)-free regimen based on sirolimus was significantly lower among recipients with ESRD (6% vs 57%, p = 0.0001), and prolonged exposure to CNI significantly increased the risk for ESRD (hazard ratio, 1.09; 95% confidence interval, 1.03-1.15; p < 0.005). Death-censored renal graft survival after KAH was 95%, 95%, and 83% at 1, 5, and 10 years, respectively. Median long-term survival of KAH patients was comparable to HTx recipients without ESRD (17.5 vs 17.1 years, p = 0.27) and significantly better compared with HTx recipients with ESRD (17.5 vs 7.3 years, p < 0.001).

CONCLUSIONS

Prolonged exposure to CNI immunosuppression medications significantly increases the risk for ESRD among HTx recipients. KAH is a good therapeutic option for HTx recipients with ESRD, with survival benefit comparable to HTx without ESRD.

Conversion From Calcineurin Inhibitors to Mammalian Target-of-Rapamycin Inhibitors in Heart Transplant Recipients: A Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

Conversion from calcineurin inhibitors (CNIs) to mammalian target-of-rapamycin inhibitors (mTORi) was systematically evaluated in heart transplant recipients (HTRs) for the first time.

METHODS

MEDLINE (PUBMED), EMBASE, Cochrane Library, and clinical trial registries were searched comprehensively. After screening for eligibility, the randomized controlled trials (RCTs) comparing continuation of CNI with conversion to mTORi therapy underwent review, quality assessment, and data extraction. Outcomes analyzed including creatinine clearance, serum creatinine level, rejection, adverse effects, and triglyceride levels were expressed as mean differences (MDs) or as risk ratios (RRs) with 95% confidence intervals (CIs).

RESULTS

This is the first systematic review evaluating converting from CNI to mTORi therapy in HTRs. A total of 4 RCTs (231 HTRs, 117 vs 114) were included in our analysis. Patients converted to mTORi had a higher creatinine clearance (MD, 19.31; 95% CI [11.16, 27.46]; P < .00001) and lower serum creatinine levels (MD, -0.15; 95% CI [-0.25, -0.05]; P = .002). Patients converted to mTORi had a significantly higher occurrence of adverse effects, which included skin diseases, gastrointestinal side effects, bone marrow suppression, and infections. There was no significant difference between the 2 groups regarding graft rejection and triglyceride levels (RR, 2.61; 95% CI [0.08, 81.25]; P = .58; MD, 22.89; 95% CI [-21.86, 67.63]; P = .32).

CONCLUSIONS

Conversion from CNI to mTORi therapy may improve the renal function in HTRs, but the patients may suffer from a high incidence of mTORi-associated adverse events. Therefore, conversion to mTORi must be carefully assessed for the benefits and risks.

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.

Safety of mTOR inhibitors in adult solid organ transplantation

INTRODUCTION

Mammalian target of rapamycin (mTOR) inhibitors (sirolimus and everolimus) are a class of immunosuppressive drugs approved for solid organ transplantation (SOT). By inhibiting the ubiquitous mTOR pathway, they present a peculiar safety profile. The increased incidence of serious adverse events in early studies halted the enthusiasm as a kidney sparing alternative to calcineurin inhibitors (CNI).

AREAS COVERED

Herein we review mTOR inhibitors safety profile for adult organ transplantation, ranging from acute side effects, such as lymphoceles, delayed wound healing, or cytopenias, to long-term ones which increase morbidity and mortality, such as cancer risk and metabolic profile. Infection, proteinuria, and cutaneous safety profiles are also addressed.

EXPERT OPINION

In the authors' opinion, mTOR inhibitors are a safe alternative to standard immunosuppression therapy with CNI and mycophenolate/azathioprine. Mild adverse events can be easily managed with an increased awareness and close monitoring of trough levels. Most serious side effects are dose- and organ-dependent. In kidney and heart transplantation mTOR inhibitors may be safely used as either low-dose de novo or through early-conversion. In the liver, conversion 4 weeks post-transplantation may reduce long-term chronic kidney disease secondary to calcineurin nephrotoxicity, without increasing hepatic artery/portal vein thrombosis.

Chronic renal insufficiency in heart transplant recipients: risk factors and management options

Renal dysfunction after heart transplantation is a frequently observed complication, in some cases resulting in significant limitation of quality of life and reduced survival. Since the pathophysiology of renal failure (RF) is multifactorial, the current etiologic paradigm for chronic kidney disease after heart transplantation relies on the concept of calcineurin inhibitor (CNI)-related nephrotoxicity acting on a predisposed recipient. Until recently, the management of RF has been restricted to the minimization of CNI dosage and general avoidance of classic nephrotoxic risk factors, with somewhat limited success. The recent introduction of proliferation signal inhibitors (PSIs) (sirolimus and everolimus), a new class of immunosuppressive drugs lacking intrinsic nephrotoxicity, has provided a completely new alternative in this clinical setting. As clinical experience with these new drugs increases, new renal-sparing strategies are becoming available. PSIs can be used in combination with reduced doses of CNIs and even in complete CNI-free protocols. Different strategies have been devised, including de novo use to avoid acute renal toxicity in high-risk patients immediately after transplantation, or more delayed introduction in those patients developing chronic RF after prolonged CNI exposure. In this review, the main information on the clinical relevance and pathophysiology of RF after heart transplantation, as well as the currently available experience with renal-sparing immunosuppressive regimens, particularly focused on the use of PSIs, is reviewed and summarized, including the key practical points for their appropriate clinical usage.

[Modern immunosuppression after solid organ transplantation]

The one common factor in solid organ transplantation is the need for lifelong maintenance immunosuppression. Drug regimens after organ transplantation typically comprise a combination of different immunosuppressive drugs. In most cases a triple drug regimen with different mechanisms of action is used. The aim is to improve both patient and graft survival while minimizing potential side effects of immunosuppressive medication. The basis of most immunosuppressive regimens is calcineurin inhibitors in combination with mycophenolic acid. There are various stages of immunosuppression after solid organ transplantation involving induction therapy, initial and long-term maintenance therapy. In each phase an individual combination of immunosuppressants is set up depending on the risk profile of the individual patient to prevent transplant rejection and organ loss. Based on these considerations, concepts of calcineurin inhibitor or steroid reduction have been established in transplant medicine in recent years. The key role in terms of development of new immunosuppressive strategies is taken by kidney transplantation, the most common solid organ transplantation performed.

Prescription trends of immunosuppressive drugs in post-heart transplant recipients in Taiwan, 2000-2009

PURPOSE

Significantly increasing heart transplantations have been performed in Taiwan in the past decades, but the trends of maintenance immunosuppression for heart transplant recipients have not been well known. In this study, we aimed to explore the trends of maintenance immunosuppressive therapy and common complications for heart transplant recipients.

METHODS

We retrospectively analyzed ambulatory prescriptions in 488 heart transplant recipients for the period 2000-2009. Patient complications after heart transplantation were also identified.

RESULTS

The annual number of new heart transplant recipients ranged from 18 to 68. The 5-year survival rate was 77.9%. The total number of regimens was 10 in 2000, and increased to 28 in 2009. Most prescriptions were immunosuppressive combinations (95.5%-89.5%). The majority of immunosuppressive regimens were a triple regimen: cyclosporine, mycophenolic acid and corticosteroid in 2009. Cyclosporine was a predominant calcineurin inhibitor with a decreasing trend from 73.9% to 59.1%, whereas the use of tacrolimus significantly increased from 11.9% to 38.4%. Mycophenolic acid was the most frequently used antimetabolite (60.1%-80.3%), while the use of azathioprine was reduced (21.6%-2.3%). From 2008, the launch of everolimus initiated a new era in the utilization of mammalian target of rapamycin inhibitors for maintenance immunosuppression.

CONCLUSIONS

Cyclosporine remained the most frequently used calcineurin inhibitors, and tacrolimus increased gradually. Mycophenolic acid was the most popular antimetabolite rather than azathioprine. The rapidly increased everolimus combined regimen may change the patterns of maintenance immunosuppression. The increasing number of combination therapies indicates an active role of everolimus and a tendency of complex tailored individual therapies.

Sirolimus conversion after heart transplant: risk factors for acute rejection and predictors of renal function response

In a randomized, comparative study of cardiac transplant patients with mild-to-moderate renal insufficiency, conversion from calcineurin inhibitors (CNIs) to sirolimus improved renal function at 1 year versus continuing CNIs, with an attendant risk of biopsy-confirmed acute rejection (BCAR). Post hoc analyses were conducted to identify predictors of BCAR and GFR improvement associated with conversion. Patients with proteinuria >500 mg/day were excluded. Univariate and multivariate regression analyses tested 13 parameters for BCAR and six for GFR improvement. In 57 sirolimus-treated patients, mean daily mycophenolate mofetil (MMF) dose was lower in those with versus without BCAR (1000 vs. 1420 mg; p = 0.014). Receiver operating characteristic analysis identified MMF dose ≤1000 mg/day as the optimal cutoff to predict BCAR. Multivariate analysis confirmed low MMF dose (odds ratio: 9.94; p = 0.007) and non-white race (odds ratio: 15.3; p = 0.06) were independently associated with BCAR. GFR improvement was evaluated in intent-to-treat patients (n = 116). Significant interaction was detected between treatment effect and preexisting diabetes status (univariate p = 0.077; multivariate p = 0.022), indicating greater beneficial effect of sirolimus in those without preexisting diabetes. These findings suggest that sirolimus is more effective in improving GFR in patients without preexisting diabetes, and adequate MMF doses are needed for sirolimus conversion.

Heart transplantation: challenges facing the field

There has been significant progress in the field of heart transplantation over the last 45 years. The 1-yr survival rates following heart transplantation have improved from 30% in the 1970s to almost 90% in the 2000s. However, there has been little change in long-term outcomes. This is mainly due to chronic rejection, malignancy, and the detrimental side effects of chronic immunosuppression. In addition, over the last decade, new challenges have arisen such as increasingly complicated recipients and antibody-mediated rejection. Most, if not all, of these obstacles to long-term survival could be prevented or ameliorated by the induction of transplant tolerance wherein the recipient's immune system is persuaded not to mount a damaging immune response against donor antigens, thus eliminating the need for chronic immunosuppression. However, the heart, as opposed to other allografts like kidneys, appears to be a tolerance-resistant organ. Understanding why organs like kidneys and livers are prone to tolerance induction, whereas others like hearts and lungs are tolerance-resistant, could aid in our attempts to achieve long-term, immunosuppression-free survival in human heart transplant recipients. It could also advance the field of pig-to-human xenotransplantation, which, if successful, would eliminate the organ shortage problem. Of course, there are alternative futures to the field of heart transplantation that may include the application of total mechanical support, stem cells, or bioengineered whole organs. Which modality will be the first to reach the ultimate goal of achieving unlimited, long-term, circulatory support with minimal risk to longevity or lifestyle is unknown, but significant progress in being made in each of these areas.