The Need for a Tailored Immunosuppression in Older Heart Transplant Recipients

Pharmacotherapy in the heart transplant recipient: A primer for nurse clinicians and pharmacists

Heart transplantation (HT) is the definitive treatment for eligible patients with end-stage heart disease. A major complication of HT is allograft rejection which can lead to graft dysfunction and death. The guiding principle of chronic immunosuppression therapy is to prevent rejection of the transplanted organ while avoiding oversuppression of the immune system, which can cause opportunistic infections and malignancy. The purpose of this review is to describe immunosuppressive management of the HT recipient-including agent-specific pharmacology and pharmacokinetics, outcomes data, adverse effects, clinical considerations, and recent guideline updates. We will also provide recommendations for medical prophylaxis of immunosuppressed patients based on the most recent clinical guidelines. Additionally, we highlight the importance of medical therapy adherence and the effect of social determinants of health on the long-term management of HT. HT recipients are a complex and high-risk population. The objective of this review is to describe basic pharmacotherapy in HT and implications for nurses and pharmacists.

Human Leukocyte Antigen-Based Risk Stratification in Heart Transplant Recipients-Implications for Targeted Surveillance

Background

Human leukocyte antigen (HLA) matching isn't routinely performed in heart transplantation. Novel allograft perfusion methods may make HLA matching feasible. The purpose of this study is to reexamine whether HLA mismatch may be used in risk stratification to improve outcomes in heart transplantation.

Methods and Results

We analyzed 34 681 recipients undergoing heart transplantation between 1987 and 2013. We used HLAMatchmaker to quantify HLA eplet mismatches and Cox regression for analysis of time to graft loss. Recipients with 4 mismatched HLA‐DR/DQ alleles and >40 eplets reached an adjusted hazard ratio (HR) for graft loss of 1.17 (95% CI 1.07–1.28) and 1.11 (95% CI 1.03–1.21), respectively. We found significant interaction between recipient age and numbers of HLA‐DR/DQ allele and eplet mismatches resulting in an adjusted HR of 1.78 (95% 1.13–2.80) and 1.82 (95% CI, 1.23–2.70), respectively. HR for both interaction terms was 0.99 (95% CI, 0.98–1.00). Risk of graft loss was more pronounced after 1 year, where recipient <40 years with 4 mismatched HLA‐DR/DQ alleles and >40 eplets had an adjusted HR of 1.51 (95% CI 1.12–2.03) and 1.32 (95% CI 1.02–1.70), respectively. Pre‐sensitized recipients with panel reactive antibodies >10% had an adjusted HR=1.27 (95% CI 1.16–1.40) for graft loss within 1 year but not thereafter. HLA eplet mismatch was independent of panel reactive antibodies on reduction of graft loss within and after 1 year, P (interaction)=0.888 and 0.389.

Conclusions

HLA mismatch may be used in risk stratification for intensified post‐transplant surveillance and therapy.

A Rationale for Age-Adapted Immunosuppression in Organ Transplantation

Demographic changes are associated with a steady increase of older patients with end-stage organ failure in need for transplantation. As a result, the majority of transplant recipients are currently older than 50 years, and organs from elderly donors are more frequently used. Nevertheless, the benefit of transplantation in older patients is well recognized, whereas the most frequent causes of death among older recipients are potentially linked to side effects of their immunosuppressants.Immunosenescence is a physiological part of aging linked to higher rates of diabetes, bacterial infections, and malignancies representing the major causes of death in older patients. These age-related changes impact older transplant candidates and may have significant implications for an age-adapted immunosuppression. For instance, immunosenescence is linked to lower rates of acute rejections in older recipients, whereas the engraftment of older organs has been associated with higher rejection rates. Moreover, new-onset diabetes mellitus after transplantation is more frequent in the elderly, potentially related to corticosteroids, calcineurin inhibitors, and mechanistic target of rapamycin inhibitors.This review presents current knowledge for an age-adapted immunosuppression based on both, experimental and clinical studies in and beyond transplantation. Recommendations of maintenance and induction therapy may help to improve graft function and to design future clinical trials in the elderly.

Understanding alterations in drug handling with aging: a focus on the pharmacokinetics of maintenance immunosuppressants in the elderly

PURPOSE OF REVIEW

This review presents current knowledge of the impact of age on the pharmacokinetics of maintenance immunosuppressants.

RECENT FINDINGS

Over the past decade, there has been a steady increase in older patients on organ transplant waiting lists. As a result, the average age of transplant recipients has significantly increased. The survival and quality-of-life benefits of transplantation in the elderly population have been demonstrated. Advancing age is associated with changes in immune responses, as well as changes in drug handling. Immunosenescence is a physiological part of aging and is linked to reduced rejection rates, but also higher rates of diabetes, infections and malignancies. Physiologic changes associated with age can have a significant impact on the pharmacokinetics of the maintenance immunosuppressive agents. Taken together, these age-related changes impact older transplant candidates and may have significant implications for managing immunosuppression in the elderly.

SUMMARY

Despite the lack of formal efficacy, safety and pharmacokinetic studies of individual immunosuppressants in the elderly transplant population, there are enough data available for practitioners to be able to adequately manage their older patients. A proficient understanding of the factors that impact the pharmacokinetics of the immunosuppressants in the elderly is essential to managing these patients successfully.

Long-term outcomes after 1000 heart transplantations in six different eras of innovation in a single center

The objective of this study was to evaluate long-term outcomes of cardiac transplantation (HTx) in different eras of innovation at a single center during a period of 27 years. We performed a retrospective analysis of 960 cardiac allograft recipients (40 re-HTx) between 1981 and 2008. The results of six different eras based on milestones in HTx were analysed: Era 1: the early years (n = 222,1981-1992); era 2: introduction of inhalative nitric oxide, prostanoids, University of Wisconsin solution (UW) replacing Bretschneider's solution (HTK,n = 118, 1992-1994); era 3: statins (n = 102, 1994-1995); era 4: tacrolimus(n = 115, 1995-1996); era 5: mycophenolate mofetil (MMF, n = 143, 1997-2000) and era 6: sirolimus (n = 300, 2000-2008). Outcome variables weresurvival, freedom from cardiac allograft vasculopathy (CAV) and from acute rejection episodes (AREs). Differences in survival was found comparing era 1 and era 2 with era 4 and era 6 (P < 0.001). Organ preservation through UW demonstrated a significantly better survival as compared with HTK(P < 0.001). Less AREs occurred in patients receiving tacrolimus-sirolimus ortacrolimus-MMF (P < 0.001). Patients receiving tacrolimus-MMF showed less CAV than when treated with cyclosporine-MMF (P < 0.005). There were more ventricular assist device implantations and more re-HTx in era 6 (P < 0.0001)than when compared with other eras. Although the causes for improvement in survival over time are multifactorial, we believe that changes in immunosuppressive therapy have had a major impact on survival.

Acute rejection after heart transplantation

Acute rejection (AR) seems to be less common with current immunosuppressive strategies; however, it remains a major cause of morbidity and mortality in the first year following heart transplantation. Despite great interest in noninvasive methods for detecting rejection, the endomyocardial biopsy remains the standard method for AR identification and, recently, the cardiac biopsy grading system has been reviewed. Moreover, the availability of several immunosuppressive drug combinations has generated confusion in the minds of clinicians. This review will focus on recently published studies that are related to the clinical impact of AR, combination regimens of chronic maintenance immunosuppression and specific therapeutic options for treating AR.