Chronic kidney disease after heart transplantation: a single-centre retrospective study at Skåne University Hospital in Lund 1988-2010

Changes in estimated glomerular filtration rate over the first year following repeat heart transplant in children and young adults

BACKGROUND

Renal function is reduced in patients undergoing heart transplant due to hemodynamic compromise, cardiorenal syndrome, and nephrotoxin exposure. No current studies evaluate renal function in retransplants.

METHODS

We reviewed all heart transplants at our center from 1995 to 2021 and matched first-time heart transplants with retransplants, based on age at transplant, sex, and race. Estimated glomerular filtration rate (eGFR) was derived from CKiD-U25 calculator using creatinine and measured prior to transplant, 1-week post-transplant, 1-3, 6, and 12 months post-transplant, and recent follow-up. Changes in eGFR were measured within and between patients using a piecewise linear mixed effect model with matching. Exploratory univariate analysis was performed to evaluate pre-transplant risk factors for decreased eGFR.

RESULTS

The unmatched cohort included 393 heart transplant recipients, with 47 being retransplants. Thirty-eight patients in both groups with at least 1 year of follow-up underwent matching. Both retransplants and first-time transplants had an initial decline in eGFR. eGFR rebounded to baseline or above baseline at 1-3 months post-transplant, but eGFR in retransplants remained significantly lower. At 1-year post-transplant, the average eGFR was 67.8 ± 4.3 mL/min/1.73 m2 versus 104.7 ± 4.3 mL/min/1.73 m2 (p < .001) in the retransplants and first-time transplants group, respectively.

CONCLUSION

This study provides data on anticipated renal trajectory following retransplantation.

Plasma Biomarkers for Clinical Assessment of Bone Mineral Density in Heart Transplanted Patients—A Single-Center Study at Skåne University Hospital in Lund

We aimed to identify plasma biomarkers that predict changes in bone mineral density (BMD) and increase the understanding of impaired BMD after heart transplantation (HT). Twenty-eight adult patients were included. Data, including densitometry and 29 plasma proteins, before and 1 year after HT were analyzed. Pre-HT plasma levels of fibroblast growth factor 23 (FGF23) correlated with post-HT T score in lumbar spine, adjusted for age, gender, and BMI (1.72 [95% CI 1.33; 2.22], p = 0.011). Change (∆; post-HT—pre-HT) in plasma levels of melusin correlated to ∆T score from the lumbar spine (p = 0.028). ∆plasma levels of TR-AP, ITGB2, and Stromelysin-1 correlated to ∆T score from the femoral neck (p < 0.05). However, no correlations remained after adjustments for age, gender, and BMI. In conclusion, elevated plasma FGF23 pre-HT predicted an increase in lumbar BMD after HT. However, the results are surprising since FGF23 is known to be inversely correlated with BMD. This may partly be explained by the complex pathophysiology in this particular cohort. Due to the explorative nature of the study and the small sample size, further investigations of biochemical markers on bone metabolism in this patient population are encouraged.

Kidney Disease After Nonkidney Solid Organ Transplant

Nonkidney solid organ transplants (NKSOTs) are increasing in the United States with improving long-term allograft and patient survival. CKD is prevalent in patients with NKSOT and is associated with increased morbidity and mortality especially in those who progress to end-stage kidney disease. Calcineurin inhibitor nephrotoxicity is a main contributor to CKD after NKSOT, but other factors in the pretransplant, peritransplant, and post-transplant period can predispose to progressive kidney dysfunction. The management of CKD after NKSOT generally follows society guidelines for native kidney disease. Kidney-protective and calcineurin inhibitor-sparing immunosuppression has been explored in this population and warrants a discussion with transplant teams. Kidney transplantation in NKSOT recipients remains the kidney replacement therapy of choice for suitable candidates, as it provides a survival benefit over remaining on dialysis.

Donor-derived cell-free DNA is associated with cardiac allograft vasculopathy

BACKGROUND

The role of donor-derived cell-free DNA (dd-cfDNA) in screening for cardiac allograft vasculopathy (CAV) is unknown. We hypothesized that dd-cfDNA correlates with CAV, markers of inflammation, and angiogenesis in stable heart transplant (HT) recipients.

METHODS

Sixty-five HT recipients ≥2 years post-transplant, without recent rejection, were stratified by high (≥0.12%) versus low levels (<0.12%) of dd-cfDNA. A targeted amplification, next-generation sequencing assay (AlloSure^® ; CareDx, Inc.) was used to detect dd-cfDNA. Peripheral blood inflammatory and angiogenesis markers were assessed using a multiplex immunoassay system (Bioplex^® ).

RESULTS

Of 65 patients, 58 patients had a known CAV status and were included. Thirty had high levels of dd-cfDNA (≥0.12%), and 28 had low levels (<0.12%). CAV was present in 63% of patients with high dd-cfDNA vs. 35% with low dd-cfDNA (p = .047). Donor-specific antibodies were present in 25% of patients with high dd-cfDNA vs. 3.8% in those with low dd-cfDNA (p = .03). There were no differences in rejection episodes, inflammatory, or angiogenesis markers. Importantly, dd-cfDNA levels were not different when stratified by time post-transplant.

CONCLUSIONS

Higher dd-cfDNA levels were associated with CAV in stable chronic HT recipients. Further studies are warranted to investigate a possible association between dd-cfDNA levels and CAV severity and whether dd-cfDNA can predict CAV progression.

Bone Mineral Density in Relation to Chronic Kidney Disease After Heart Transplantation: A Retrospective Single-center Study at Skåne University Hospital in Lund 1988-2016

Background.

Our aim was to investigate the bone mineral density (BMD) evolution and incidence of osteoporosis in relation to chronic kidney disease (CKD) up to 10 years after heart transplantation (HT).

Methods.

A retrospective analysis was performed on 159 HT patients at Skåne University Hospital in Lund 1988–2016.

Results.

The median follow-up time was 6.1 years (interquartile range = 7.5 y). HT patients with CKD stage <3 or normal kidney function before HT exhibited a greater mean BMD loss in the lumbar spine, compared to patients with CKD stage ≥3 before HT, at the first (−6.6% versus −2.5%, P = 0.029), second (−3.7% versus 2.1%, P = 0.018), and third (−2.0% versus 4.1%, P = 0.047) postoperative years, respectively. All included HT patients exhibited a BMD loss in the femoral neck at the first postoperative year (−8.8% [−10.3 to −7.3] in patients with CKD stage <3 or normal kidney function and −9.3% [−13.2 to −5.5] in patients with CKD stage ≥3 before HT), which was not fully reversed up to 10 years after HT. In adjusted models, CKD stage <3 before HT did not predict osteopenia and osteoporosis in the lumbar spine or femoral neck.

Conclusions.

CKD before HT did not predict BMD loss or osteoporosis development after HT. The study is, however, limited by a lack of data on fractures, and further studies on the relationship between CKD and postoperative bone strength are encouraged.

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.

Association of Whole Blood Tacrolimus Concentrations with Kidney Injury in Heart Transplantation Patients

Background and Objectives

Acute kidney injury (AKI) is frequently observed after heart transplantation and is associated with morbidity and mortality. However, many confounding factors also contribute to the development of AKI in heart transplants. We hypothesized that supratherapeutic whole-blood tacrolimus trough concentrations are associated with AKI.

Methods

In a retrospective observational cohort from April 2005 to December 2012, all adult heart transplantation patients were included. AKI was assessed in the first 2 weeks after transplantation as classified by the Kidney Disease Improving Global Outcomes Network (KDIGO). Whole-blood tacrolimus trough concentrations were determined from day 1 to day 14 and at 1, 3, 6 and 12 months post-transplantation. The therapeutic range was 9 to 15 ng/ml in the first 2 months and tapered to 5–8 ng/ml thereafter. The relationship between supratherapeutic tacrolimus trough concentrations and AKI was evaluated. The impact of various potentially confounding factors on tacrolimus concentrations and AKI was considered.

Results

We included 110 patients. AKI occurred in 57% of patients in the first week. Recovery from AKI was seen in 24%. The occurrence of chronic kidney disease (CKD) was 19% at 1 year. Whole-blood tacrolimus trough concentrations were often supratherapeutic and, despite correction for confounding factors, independently associated with AKI (OR 1.66; 95% CI 1.20–2.31).

Conclusions

Supratherapeutic whole-blood tacrolimus trough concentrations are independently associated with the development of AKI in adult heart transplantation patients. More stringent dosing of tacrolimus early after transplantation may be critical in preserving the kidney function.

Electronic supplementary material

The online version of this article (10.1007/s13318-017-0453-7) contains supplementary material, which is available to authorized users.

Osteoporosis following heart transplantation and immunosuppressive therapy

Heart transplantation (HT) remains the ultimate final therapy for patients with end-stage heart failure, who despite optimal medical and surgical treatments exhibit severe symptoms. To prevent rejection of the transplanted organ, HT patients require life-long immunosuppressive therapy. The goal of the immunosuppression is to minimise the risk of immune-mediated graft rejection, while avoiding clinical side-effects. Current immunosuppressive agents have yielded good survival outcome, however, complications of the immunosuppressive therapy, such as impaired bone strength and increased fracture risk, are common among HT patients rendering increased morbidity and mortality rates. The main aim of the present review was to summarise current knowledge on bone strength impairment after HT and concomitant immunosuppressive therapy.

Brain natriuretic peptide and right heart dysfunction after heart transplantation

Heart transplantation (HT) should normalize cardiac endocrine function, but brain natriuretic peptide (BNP) levels remain elevated after HT, even in the absence of left ventricular hemodynamic disturbance or allograft rejection. Right ventricle (RV) abnormalities are common in HT recipients (HTx), as a result of engraftment process, tricuspid insufficiency, and/or repeated inflammation due to iterative endomyocardial biopsies. RV function follow-up is vital for patient management as RV dysfunction is a recognized cause of in-hospital death and is responsible for a worse prognosis. Interestingly, few and controversial data are available concerning the relationship between plasma BNP levels and RV functional impairment in HTx. This suggests that infra-clinical modifications, such as subtle immune system disorders or hypoxic conditions, might influence BNP expression. Nevertheless, due to other altered circulating molecular forms of BNP, a lack of specificity of BNP assays is described in heart failure patients. This phenomenon could exist in HT population and could explain elevated BNP plasmatic levels despite a normal RV function. In clinical practice, intra-individual change in BNP over time, rather than absolute BNP values, might be more helpful in detecting right cardiac dysfunction in HTx.

Impact of postoperative pulmonary hypertension on outcome after heart transplantation

OBJECTIVES

We wanted to investigate the effects of postoperative pulmonary hypertension (PH_postop: mean pulmonary artery pressure [MPAP] ≥ 25 mmHg), diastolic pressure gradient (DPG), pulmonary vascular resistance (PVR), and repeated hemodynamic measurements on long-term survival after heart transplantation (HT).

DESIGN

Eighty-nine patients who underwent HT at Skåne University Hospital in Lund in the period 1988-2010 and who were evaluated with right-heart-catheterization at rest, prior to HT and repeatedly during the first postoperative year, were grouped based on their MPAP, DPG, and PVR.

RESULTS

One year after HT, survival was lower in patients with PH_postop than in those without, in patients with DPG ≥7 mmHg than in those with DPG <7 mmHg, and in patients with PVR >3 WU than in those with PVR ≤3 WU. Moreover, compared to patients with no PH_postop or with PH_postop at one evaluation during the first year after HT, PH_postop at repeated evaluations was associated with higher mortality (hazard ratio 3.4, 95% CI 1.4-8.0). There was no significant difference in acute cellular rejection between patients with and without PH_postop, but postoperative kidney function was worse in patients with repeated PH_postop.

CONCLUSIONS

When defined according to present guidelines, PH one year after HT may emerge as a prognostic marker for long-term outcome after HT. Moreover, PH_postop at repeated evaluations during the first year after HT had stronger prognostic value than PH_postop at a single examination, illustrating a means of identifying a high-risk population. However, confirmation in larger multi-center studies is warranted.