Impact of preoperative renal replacement therapy on the clinical outcome of heart transplant patients

Early Renal Outcomes Following Heart Transplantation Using Organs Procured After Circulatory Death

BACKGROUND

Transplantation using hearts obtained through donation after circulatory death (DCD) is increasing, but data on recipient renal outcomes are limited.

METHODS AND RESULTS

Patients at a single institution who underwent heart transplantation using organs procured through DCD or donation after brain death (DBD) from April 2016 to August 2022 were included in this retrospective cohort study. Hemodynamic measures were collected via right heart catheterization performed 1 week after transplantation. Posttransplantation renal outcomes included estimated glomerular filtration rate at 1 week, 4 weeks, and 16 weeks, and the incidence of acute kidney injury (AKI) and renal replacement therapy within 1 week. The analysis included 225 patients (55 recipients of DCD). Baseline characteristics were comparable between recipients of DCD and DBD. Renal outcomes within 1 week posttransplantation in recipients of DCD were similar to recipients of DBD, including percent change in estimated glomerular filtration rate (-37.9% [-58.6 to -6.2] versus -31.9% [-52.4 to -9.9]; P=0.91), incidence of AKI (47.3% versus 46.5%; P>0.99) and incidence of renal replacement therapy (3.6% versus 4.7%; P>0.99). Recipients of DCD with AKI within 1 week ("early AKI") did not recover to baseline estimated glomerular filtration rate (75.8 [60.2-91.3] mL/min per 1.73 m2) by week 16 (59.3 [46.9-73.6] mL/min per 1.73 m2; P=0.002), whereas recipients without early AKI exhibited comparable estimated glomerular filtration rate to baseline by week 4 (84.5 [70.8-98.5] mL/min per 1.73 m2; P=0.084). Similar trends were observed in recipients of DBD.

CONCLUSIONS

Recipients of DCD demonstrated similar renal outcomes compared with recipients of DBD, supporting the ongoing use of DCD transplantation. Early AKI was associated with persistent renal dysfunction for recipients of both DCD and DBD.

Severe Acute Kidney Injury Postheart Transplantation: Analysis of Risk Factors

Background

Acute kidney injury (AKI) is a common complication postheart transplantation and is associated with significant morbidity and increased mortality.

Methods

We conducted a single-center, retrospective, observational cohort study of 109 consecutive patients undergoing heart transplantation between September 2019 and September 2021 to determine major risk factors for, and the incidence of, severe postoperative AKI as defined by Kidney Disease Improving Global Outcomes criteria in the first 48-h posttransplantation and the impact that this has on mortality and dialysis dependence.

Results

One hundred nine patients were included in our study, 83 of 109 (78%) patients developed AKI, 42 (39%) developed severe AKI, and 37 (35%) required renal replacement therapy in the first-week posttransplantation. We found preoperative estimated glomerular filtration rate (eGFR), postoperative noradrenaline dose, and the need for postoperative mechanical circulatory support to be independent risk factors for the development of severe AKI. Patients who developed severe AKI had a 19% 12-mo mortality compared with 1% for those without. Of those who survived to hospital discharge, 20% of patients in the severe AKI group required dialysis at time of hospital discharge compared with 3% in those without severe AKI.

Conclusion

Severe AKI is common after heart transplantation. Preoperative kidney function, postoperative vasoplegia with high requirements for vasoactive drugs, and graft dysfunction with the need for mechanical circulatory supports were independently associated with the development of severe AKI in the first-week following heart transplantation. Severe AKI is associated with a significantly increased mortality and dialysis dependence at time of hospital discharge.

Elevated serum albumin-to-creatinine ratio as a protective factor on outcomes after heart transplantation

Background

The purpose of this study was to investigate the prognostic significance of serum albumin to creatinine ratio (ACR) in patients receiving heart transplantation of end-stage heart failure.

Methods

From January 2015 to December 2020, a total of 460 patients who underwent heart transplantation were included in this retrospective analysis. According to the maximum Youden index, the optimal cut-off value was identified. Kaplan-Meier methods were used to describe survival rates, and multivariable analyses were conducted with Cox proportional hazard models. Meanwhile, logistic regression analysis was applied to evaluate predictors for postoperative complications. The accuracy of risk prediction was evaluated by using the concordance index (C-index) and calibration plots.

Results

The optimal cut-off value was 37.54 for ACR. Univariable analysis indicated that recipient age, IABP, RAAS, BB, Hb, urea nitrogen, D-dimer, troponin, TG, and ACR were significant prognostic factors of overall survival (OS). Multivariate analysis showed that preoperative ACR (HR: 0.504, 95% = 0.352-0.722, P < 0.001) was still an independent prognostic factor of OS. The nomogram for predicting 1-year and 5-year OS in patients who underwent heart transplantation without ACR (C-index = 0.631) and with ACR (C-index = 0.671). Besides, preoperative ACR level was a significant independent predictor of postoperative respiratory complications, renal complications, liver injury, infection and in-hospital death. Moreover, the calibration plot showed good consistency between the predictions by the nomogram for OS and the actual outcomes.

Conclusion

Our research showed that ACR is a favorable prognostic indicator in patients of heart transplantation.

Direct Extracorporeal Membrane Oxygenation Bridged Heart Transplantation: The Importance of Multi-Organ Failure

Background and Objectives

Recently, approximately 40% of all heart transplantation (HTx) in South Korea are performed using the direct extracorporeal membrane oxygenation (ECMO) bridging method. We conducted a study to examine the clinical outcome of direct ECMO-bridged HTx and to investigate the impact of multi-organ failure (MOF).

Methods

From June 2014 to September 2022, a total of 96 adult patients who underwent isolated HTx at a single tertiary hospital were included in the study. The patients were sub-grouped into ECMO (n=48) and non-ECMO group (n=48), and the ECMO group was subdivided into awake (n=22) and non-awake (n=26) groups based on mechanical ventilator (MV) dependency. Baseline characteristics, 30-day, and 1-year mortality were analyzed retrospectively.

Results

The 1-year survival rate was significantly lower in the ECMO group (72.9% vs. 95.8%, p=0.002). There was a significant difference in the 30-day survival rate between the awake and non-awake ECMO groups (81.8% vs. 65.4%, p=0.032). In the univariate analysis of logistic regression for 1-year mortality, the odds ratio was 8.5 for ECMO bridged HTx compared to the non-ECMO group, 12.3 in patients who required MV (p=0.003), and 23 with additional hemodialysis (p<0.001).

Conclusions

Patients who required MV in ECMO bridged HTx showed higher preoperative MOF rates and early mortality than those extubated. When considering ECMO bridged HTx, the severity of MOF should be thoroughly investigated, and careful patient selection is necessary.

Value of Renal Histology in Predicting Cardiorenal Outcomes in Heart Transplant-listed Patients

Cardiorenal syndrome (CRS) contributes significantly to morbidity and mortality in patients requiring mechanical circulatory support and transplantation. There are no validated markers to predict major adverse kidney events (MAKEs), for which simultaneous heart-kidney transplant (SHKT) could offer improved survival. We evaluate renal histology in predicting MAKEs in transplant-listed patients.

Methods

We identified 18 patients with renal histology consistent with CRS from 655 consecutive heart transplant-listed patients between 2010 and 2019. Biopsies were analyzed for glomerular, tubular, interstitial, and arteriolar changes tallied to give a biopsy chronicity score. The primary outcome, MAKE, was a composite of death, need for renal replacement therapy (RRT), or estimated glomerular filtration rate decline >50%. These were evaluated at 2 time points: before and following the transplant. Secondary outcomes included the individual components of the composite outcomes and the need for short-term RRT following the transplant.

Results

The mean age was 52.3 y, 22% were female. Five patients did not survive to transplant. One patient underwent successful SHKT. MAKE occurred in 8 of 18 before the transplant and in 8 of 13 following the transplant. Neither outcome was predicted by baseline biochemistry. The biopsy chronicity score was significantly higher in patients with MAKE before transplant (4.3 versus 1.7, P = 0.024) and numerically higher in patients requiring short-term RRT following transplant (3.2 versus 0.7, P = 0.075). Contrary to limited previous literature, interstitial fibrosis did not predict any outcome, whereas tubular atrophy and arteriosclerosis were associated with MAKE before transplant.

Conclusions

A higher biopsy chronicity score was associated with adverse kidney endpoints, raising its potential utility over standard biochemistry in considering SHKT referral.

Impact of predicted heart mass-based size matching on survival after heart transplantation in Korea: Analysis of the Korean Organ Transplant Registry

BACKGROUND

Previous studies regarding donor-recipient size and sex matching in heart transplantation (HTx) mainly included Caucasians with only a small portion of Asians. Even predicted heart mass (PHM) has not yet been elucidated in Asians. We evaluated the association between donor-recipient sex and size matching, including mismatching by PHM, and post-heart transplant survival in Korea.

METHODS

We enrolled 660 adult HTx recipients between January 2014 and December 2020 using the Korean Organ Transplant Registry data. Recipients were categorized based on donor-recipient PHM, body weight, and sex matching. The primary outcome was 1-year mortality and retransplantation after HTx and survival analyses were performed using Kaplan-Meier method and Cox proportional hazard models.

RESULTS

Among 660 patients, 74 (11.2%), 404 (61.2%), and 182 (27.6%) received undersized (<-15%), matched (-15% to 20%), and oversized (>20%) hearts by PHM, respectively. Size mismatching by PHM was present in a large number of sex-mismatched patients with 85.1% of male donor-female recipients being classified as oversized by PHM and 62.2% of female donor-male recipients being classified as undersized by PHM. Recipients of undersized or oversized hearts by PHM showed an increased 1-year mortality compared with recipients of matched-size hearts (14.8% versus 9.7%; log-rank p = 0.038). The increased mortality persisted after adjusting for other factors affecting mortality (hazard ratio = 1.60, 95% confidence interval: 1.01-2.56). These associations were not shown in obese recipients (body mass index ≥25 kg/m²). Heart size mismatching by body weight (log-rank p = 0.332) or sex mismatching (all, log-rank p > 0.05) did not predict 1-year mortality after HTx.

CONCLUSION

Heart size matching by PHM, not by body weight or sex, was associated with increased 1-year mortality after HTx in Korea.

CALL-K score: predicting the need for renal replacement therapy in cardiogenic shock

AIMS

The clinical predictors and outcomes of patients with cardiogenic shock (CS) requiring renal replacement therapy (RRT) have not been studied previously. This study assesses the impact of RRT on mortality in patients with CS and aims to identify clinical factors that contribute to the need of RRT.

METHODS AND RESULTS

Consecutive patients presenting with CS were included from a prospective registry of cardiac intensive care unit admissions at a single institution between 2014 and 2020. Of the 1030 patients admitted with CS, 123 (11.9%) received RRT. RRT was associated with higher 1-year mortality [adjusted hazard ratio = 1.62, 95% confidence interval (CI) 1.02-2.14], and a higher in-hospital incidence of sepsis [risk ratio = 2.76, P < 0.001], and pneumonia (risk ratio = 2.9, P = 0.001). Those who received RRT were less likely to receive guideline-directed medical treatment at time of discharge, undergo heart transplantation (2.4% vs. 11.5%, P = 0.002) or receive a durable left ventricular assist device (0.0% vs. 11.6%, P < 0.001). Five variables at admission best predicted the need for RRT (age, lactate, haemoglobin, use of pre-admission loop diuretics, and admission estimated glomerular filtration rate) and were used to generate the CALL-K 9-point risk score, with better discrimination than creatinine alone (P = 0.008). The score was internally validated (area under the curve = 0.815, 95% CI 0.739-0.835) with good calibration (Hosmer-Lemeshow P = 0.827).

CONCLUSIONS

RRT is associated with worse outcomes, including a lower likelihood to receive advanced heart failure therapies in patients with CS. A risk score comprising five variables routinely collected at admission can accurately estimate the risk of needing RRT.