Chronic Renal Dysfunction in Maintenance Heart Transplant Patients: The ICEBERG Study

Subsequent kidney transplant after pediatric heart transplant: Prevalence and risk factors

Pediatric heart failure and transplantation carry associated risks for kidney failure and potential need for kidney transplant following pediatric heart transplantation (KT/pHT). This retrospective, United Network of Organ Sharing study of 10,030 pediatric heart transplants (pHTs) from 1987 to 2020 aimed to determine the incidence of waitlisting for and completion of KT/pHT, risk factors for KT/pHT, and risk factors for nonreceipt of a KT/pHT. Among pHT recipients, 3.4% were waitlisted for KT/pHT (median time of 14 years after pHT). Among those waitlisted, 70% received a KT/pHT, and 18% died on the waitlist at a median time of 0.8 years from KT/pHT waitlisting (median age of 20 years). Moderate-high sensitization at KT/pHT waitlisting (calculated panel reactive antibody, ≥ 20%) was associated with a lower likelihood of KT/pHT (adjusted hazard ratio, 0.67; 95% confidence interval, 0.47-0.95). Waitlisting for heart transplantation simultaneously with kidney transplant (adjusted hazard ratio, 3.73; 95% confidence interval, 2.01-6.92) was associated with increased risk of death on the KT/pHT waitlist. While the prevalence of KT/pHT is low, there is substantial mortality among those waitlisted for KT/pHT. These findings suggest a need to consider novel risk factors for nonreceipt of KT/pHT and death on the waitlist in prioritizing criteria/guidelines for simultaneous heart-kidney transplantation.

Post-transplant ejection fraction and renal failure in cardiac transplant recipients: An analysis of the OPTN database

BACKGROUND

Despite improved life expectancy from a heart transplant, transplant recipients remain at high risk for renal dysfunction and failure, including end-stage kidney disease (ESKD). The onset of ESKD is a poor prognostic marker and is associated with increased mortality in this setting, as in others. There is a need to identify risk factors for ESKD among heart transplant recipients in contemporary settings.

METHODS

We conducted an analysis of adult heart transplant recipients transplanted between 2008 and 2021 in the Organ Procurement and Transplantation Network database. 22 737 adult recipients of heart transplants alone were included in this analysis. We examined LVEF measured 1 year after transplant, and LVEF updated annually for association with ESKD using multivariate Cox regression models.

RESULTS

LVEF at 1-year after transplant was associated with ESKD in multivariate models (Hazard Ratio 1.33 per 10-unit decrease, 95% CI 1.23-1.43, p < .001). In multivariate models using categorized LVEF, mildly reduced ejection fraction (EF 40%-50%) was associated with ESKD (HR 1.76, 95% CI 1.45-2.14, p < .001), as was reduced ejection fraction (EF < 40%, HR 2.86, 95% CI 2.01-4.07, p < .001), relative to individuals with preserved ejection fraction (EF > 50%). These associations were consistent when using annually updated ejection fraction.

CONCLUSIONS

Post-transplant left ventricular ejection fraction has value in predicting end stage kidney disease among adults who receive heart transplants alone. LVEF is routinely measured as part of contemporary post heart transplant care, and a diminished LVEF should signal to clinicians that a recipient is at increased risk of renal failure.

Severely Reduced Kidney Function Assessed by a Single eGFR Determination at the Time of an Isolated Heart Transplant Does Not Predict Inevitable Posttransplant ESKD

BACKGROUND

Consensus guidelines advise simultaneous heart kidney transplantation (SHK) in heart candidates with an estimated glomerular filtration rate (eGFR) of <30 mL/min/1.73 m 2 . We hypothesize that a significant fraction of such patients would not need an SHK, even though a graded increase in mortality and end-stage kidney disease (ESKD) would be seen with decrements in eGFR.

METHODS

United Network of Organ Sharing data for isolated heart transplants between 2000 and 2020 were divided into two groups based on eGFR at transplant (≤20 mL/min/1.73 m 2 and 21-29 mL/min/1.73 m 2 ). The primary outcome was mortality and secondary outcome was ESKD posttransplant. Cox regression and cumulative incidence competing risk methods were used to compare risk of mortality and ESKD.

RESULTS

There was no difference in mortality (adjusted hazard ratio [aHR] 0.82 [95% confidence interval, CI: 0.60-1.11, P = 0.21]) or ESKD (aHR 1.01 [95% CI: 0.49-2.09, P = 0.96]) between the two groups (≤20 versus 21-29). The overall incidence of ESKD for the entire cohort at 1, 5, and 10 y were 1.5%, 9.5%, and 20%.

CONCLUSIONS

Although risk of ESKD is highest in heart candidates with an eGFR <30 mL/min/1.73 m 2 , <10% of patients reach ESKD within 5 y' and most will recover significant renal function posttransplant. More refined selection criteria are required to identify candidates for SHK.

Management of long-term cardiovascular risk factors post organ transplant

PURPOSE OF REVIEW

Cardiovascular disease is one of the leading causes of death in solid organ transplant (SOT) recipients. Early identification of cardiovascular risk factors and their adequate management in this population is key for prevention and improved outcomes.

RECENT FINDINGS

Approximately 80% of SOT present one or more cardiovascular risk factors, with increasing prevalence with time posttransplantation. They are due to the interplay of pretransplant conditions and metabolic consequences of immunosuppressive agents, mainly corticosteroids and calcineurin inhibitors. Among the pharmacological management strategies, statins have shown an important protective effect in SOT.

SUMMARY

Strict surveillance of cardiovascular risk factors is recommended in SOT due to their high prevalence and prognostic implications. Further studies on the best managements strategies in this population are needed.

Change in Renal Function and Its Impact on Survival in Chronic Kidney Disease Patients Bridged to Heart Transplantation With a Left Ventricular Assist Device

The study investigates the incidence of change in renal function and its impact on survival in renal dysfunction patients who were bridged to heart transplantation with a left ventricular assist device (BTT-LVAD). BTT-LVAD patients with greater than or equal to moderately reduced renal function (estimated glomerular filtration rate [eGFR] ≤ 60 ml/min/1.73 m2) at the time of listing between 2008 and 2018 were identified from a prospectively maintained database of the United Network for Organ Sharing. Patients with a baseline eGFR less than or equal to 15 ml/min/1.73 m2 or on dialysis were excluded. Patients were divided into three groups based on percent change ([Pretransplant eGFR - listing eGFR/listing glomerular filtration rate (GFR)] × 100) in eGFR: Improvement greater than or equal to 10%, no change, decline greater than or equal to 10%, and their operative outcomes were compared. Posttransplant survival was estimated and compared among the three groups with the Kaplan-Meier survival curves and the log-rank test. Cox proportional hazards modeling was used to identify predictors of posttransplant survival. Out of 14,395 LVAD patients, 1,622 (11%) met the inclusion criteria. At the time of transplant, 900 (55%) had reported an improvement in eGFR greater than or equal to 10%, 436 (27%) had no change, and 286 (18%) experienced a decline greater than or equal to 10%. Postoperatively, the incidence of dialysis was higher in the decline than in the unchanged or improved groups (22% vs. 12% vs. 12%; p = 0.002). After a median follow-up of 5 years, there was no difference in posttransplant survival among the stratified groups (improved eGFR: 24.8%, unchanged eGFR: 23.2%, declined eGFR: 20.3%; p = 0.680). On Cox proportional hazard modeling, independent predictors of worse survival were: [hazard ratio: 95% CI; p] history of diabetes (1.43 [1.13-1.81]; p = 0.002) or tobacco use (1.40 [1.11-1.79]; p = 0.005) and ischemic time greater than 4 hours (1.36 [1.03-1.76]; p = 0.027). More than half of the patients with compromised renal function who undergo BTT-LVAD demonstrate an improvement in renal function at the time of transplant. A 10% change in GFR while listed was not associated with worse posttransplant survival.

Prognostic Factors of Renal Outcomes after Heart Transplantation: A Nationwide Retrospective Study

Renal dysfunction after heart transplantation (HT) is associated with poor survival. We investigated the predictive factors of renal outcomes after HT using nationwide cohort data. In this retrospective cohort study using the Health Insurance Review and Assessment database of Korea, 654 patients who received HT between 2008 and 2016 and survived until discharge after HT were analyzed. The median (interquartile range) age was 52 (40-60) years, and 68.1% were male. Perioperative renal replacement therapy (RRT) was performed in 27.8% of patients. During 2.8 years of median followup, end-stage kidney disease (ESKD) developed in 12 patients (1.8%). In a fully adjusted model, RRT > 3 weeks, the use of inotropes/vasopressors and non-use of ACEi/ARB were associated with ESKD. Preexisting renal disease tended to be associated with ESKD. Among the 561 patients without preexisting CKD, 104 (18.5%) developed chronic kidney disease (CKD). Age, extracorporeal membrane oxygenation, and RRT were associated with the development of CKD after HT. Our nationwide cohort study demonstrated that perioperative RRT was a predictor of poor renal outcomes after HT. These results suggest that an active renoprotective strategy is required during the perioperative period.

Clinical Factors Associated with Renal Outcome After Heart Transplantation

Cardiorenal syndrome (CRS) frequently occurs in end-stage heart failure patients waiting for heart transplantation (HT). Decision-making regarding simultaneous heart and kidney transplantation is an unresolved issue in these patients. We investigated clinical factors associated with renal outcome after HT. A total of 180 patients who received HT from 1996 to 2015 were included. Factors associated with early post-HT chronic kidney disease (CKD, estimated glomerular filtration rate [eGFR] < 60 mL/minute/1.73 m² within 1 year post-HT), post-HT end-stage kidney disease (ESKD), and significant renal function improvement (%ΔeGFR > 15%) at 1 year post-HT were analyzed. Early post-HT CKD and post-HT ESKD developed in 61 (33.9%) and 8 (4.4%) of 180 patients, respectively. Old age was only independently associated with early post-HT CKD and preexisting CKD tended to be associated with early post-HT CKD. Old age and preexisting CKD were independently associated with post-HT ESKD. Low pre-HT eGFR and preoperative renal replacement therapy were not associated with early post-HT CKD or post-HT ESKD. Young age, low pre-HT eGFR, and high %ΔeGFR 1 month post-HT were independently associated with significant renal function improvement. Preoperative renal function, including preoperative RRT, was not associated with post-HT mortality. In conclusion, preexisting CKD may impact renal outcomes after HT, but preoperative severe renal dysfunction, even that severe enough to require RRT, may not be a contraindication for HT alone. Our data suggest the necessity of early HT in end-stage heart failure patients with CRS and the importance of careful management during the early postoperative period.

Heart and kidney transplant: should they be combined or subsequent?

AIMS

End-stage heart failure patients often present with severe kidney failure and have limited treatment options. We compared the clinical characteristics and outcomes among end-stage heart and kidney failure patients who underwent combined heart and kidney transplant (HKTx) with those who underwent kidney transplant after heart transplant (KAH).

METHODS AND RESULTS

All patients from 2007-2016 who underwent combined HKTx (n = 715) and those who underwent KAH (n = 130) using the United Network for Organ Sharing database were included. Kaplan-Meier curves and Cox models compared survivals and identified predictors of death. Number of combined HKTx performed annually in United States increased from 59 in 2007 to 146 in 2016 whereas KAH decreased from 34 in 2007 to 6 in 2016. Among KAH patients, average wait time for kidney transplant was 3.0 years, time to dialysis or to kidney transplant after heart transplant did not differ with varying severity of kidney disease at baseline (P for both >0.05). Upon follow-up (mean 3.5 ± 2.7 years), 151 patients died. In multivariable models, patients who underwent combined HKTx had 4.7-fold greater risk of death [95% confidence interval (CI) 2.4-9.4) than KAH patients upon follow up. A secondary analysis using calculation of survival only after kidney transplant for KAH patients still conferred higher risk for combined HKTx patients [hazard ratio (HR) 2.6 95% CI 1.33-5.15]. In subgroup analyses after excluding patients on dialysis (HR 3.99 95% CI 1.98-8.04) and analysis after propensity matching for age, gender, and glomerular filtration rate (HR 3.01 95% CI 1.40-6.43) showed similar and significantly higher risk for combined HKTx patients compared with KAH patients. Lastly, these results also remained unchanged after excluding transplant centres who performed only one type of procedure preferentially, i.e. HKTx or KAH (HR 4.70 95% CI 2.35-9.42).

CONCLUSIONS

National registry data show continual increase in combined HKTx performed annually in the United States but inferior survival compared with KAH patients. Differences in patient characteristics or level of kidney dysfunction at baseline do not explain these poor outcomes among HKTx patients compared with KAH patients. Consensus guidelines are greatly needed to identify patients who may benefit more from dual organ transplants.

Incidence of end-stage renal disease after heart transplantation and effect of its treatment on survival

Aims

Many heart transplant recipients will develop end‐stage renal disease in the post‐operative course. The aim of this study was to identify the long‐term incidence of end‐stage renal disease, determine its risk factors, and investigate what subsequent therapy was associated with the best survival.

Methods and results

A retrospective, single‐centre study was performed in all adult heart transplant patients from 1984 to 2016. Risk factors for end‐stage renal disease were analysed by means of multivariable regression analysis and survival by means of Kaplan–Meier. Of 685 heart transplant recipients, 71 were excluded: 64 were under 18 years of age and seven were re‐transplantations. During a median follow‐up of 8.6 years, 121 (19.7%) patients developed end‐stage renal disease: 22 received conservative therapy, 80 were treated with dialysis (46 haemodialysis and 34 peritoneal dialysis), and 19 received a kidney transplant. Development of end‐stage renal disease (examined as a time‐dependent variable) inferred a hazard ratio of 6.45 (95% confidence interval 4.87–8.54, P < 0.001) for mortality. Tacrolimus‐based therapy decreased, and acute kidney injury requiring renal replacement therapy increased the risk for end‐stage renal disease development (hazard ratio 0.40, 95% confidence interval 0.26–0.62, P < 0.001, and hazard ratio 4.18, 95% confidence interval 2.30–7.59, P < 0.001, respectively). Kidney transplantation was associated with the best median survival compared with dialysis or conservative therapy: 6.4 vs. 2.2 vs. 0.3 years (P < 0.0001), respectively, after end‐stage renal disease development.

Conclusions

End‐stage renal disease is a frequent complication after heart transplant and is associated with poor survival. Kidney transplantation resulted in the longest survival of patients with end‐stage renal disease.

Changes in Renal Function After Heart Transplantation

Renal function after heart transplantation (HTx) typically follows a biphasic pattern and an initial decay within 1 to 2 years. Trajectory of renal function after HTx is less reported, especially in Asia. The aims of this cohort study were to describe the changes in HTx recipients' serum creatinine and estimated glomerular filtration rate (eGFR) levels 5 years following HTx in Taiwan.

METHODS

We retrospectively reviewed 5 years of 440 consecutive adult patients (≥ 18 years) who underwent first HTx from June 1987 to December 2014 at the National Taiwan University Hospital.

RESULTS

Among 422 participants, they received induction therapy consisting of intravenous rabbit antithymocyte globulin. Here, we illustrated the trends over the years by dividing the subjects into 2 groups based on their immunosuppressive regimen of transplantation (1987-2002 and 2003-2014) The pretransplantation median serum creatinine concentration level was 1.2 mg/dL, rose to 1.4 mg/dL at 3 months after surgery, and remained steady over 5 years after HTx. Pretransplant median eGFR was 67 mL/min/1.73 m².The median serum creatinine concentration level and eGFR at baseline were all significantly difference than pretransplantation (P > .05). This result has showed that an initial steep decline within 3 months after transplant remained stable 5 years after HTx.

CONCLUSION

As renal function deteriorates after HTx, we observed a steep decline in serum creatinine level and glomerular filtration rate within the 3 months after HTx, followed by a slow rate of deterioration over the following months. We found a time-related progressive deterioration in renal function during the 5 years after HTx.

Complications of Cardiac Transplantation

PURPOSE OF REVIEW

Despite the improvement in medical therapy for heart failure and the advancements in mechanical circulatory support, heart transplantation (HT) still remains the best therapeutic option to improve survival and quality of life in patients with advanced heart failure. Nevertheless, HT recipients are exposed to the risk of several potential complications that may impair their outcomes. In this article, we aim to provide a practical and scholarly framework for clinicians approaching heart transplant medicine, as well as a concise update for the experienced readers on the most relevant post-HT complications.

RECENT FINDINGS

While recognizing that most of the treatments herein discussed are based more on experience than on solid scientific evidence, significant step forward has been made in particular in the recognition and management of primary graft dysfunction, antibody-mediated rejection, and renal dysfunction. Complications after HT may vary according to the time from surgery and can be related to graft function and pathology or to diseases and dysfunctions occurring in other organs or systems, mainly as side effects of immunosuppressive drugs and progression of pre-existing conditions. Future research needs to focus on improving precision diagnostics of causes of graft dysfunction and on reaching an optimal and customized balance between efficacy and toxicities of immunosuppressive strategies.

Long-term outcomes and management of the heart transplant recipient

Cardiac transplantation remains the gold standard in the treatment of advanced heart failure. With advances in immunosuppression, long-term outcomes continue to improve despite older and higher risk recipients. The median survival of the adult after heart transplantation is currently 10.7 years. While early graft failure and multiorgan system dysfunction are the most important causes of early mortality, malignancy, rejection, infection, and cardiac allograft vasculopathy contribute to late mortality. Chronic renal dysfunction is common after heart transplantation and occurs in up to 68% of patients by year 10, with 6.2% of patients requiring dialysis and 3.7% undergoing renal transplant. Functional outcomes after heart transplantation remain an area for improvement, with only 26% of patients working at 1-year post-transplantation, and are likely related to the high incidence of depression after cardiac transplantation. Areas of future research include understanding and managing primary graft dysfunction and reducing immunosuppression-related complications.

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.

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.