Acute Kidney Injury as a Complication of Cardiac Transplantation: Incidence, Risk Factors, and Impact on 1-year Mortality and Renal Function

A contemporary simple risk score for prediction of severe acute kidney injury after heart transplantation

BACKGROUND

The aim of this study was to develop a simple risk score to estimate severe acute kidney injury (AKI) risk based on a large contemporary heart transplantation (HT) cohort.

METHODS

From 1 January 2015 to 31 December 2021, all consecutive HT recipients in our institute were included and analysed for the occurrence of AKI within the first seven postoperative days. Patients transplanted between 2015 and 2019 comprised the derivation cohort, and those transplanted between 2020 and 2021 formed the validation cohort. The primary endpoint was severe AKI (AKI stages 2-3). The impact of severe AKI on 90 day mortality was also evaluated.

RESULTS

Overall, 430 HT patients were included in the derivation cohort, and 108 were included in the validation cohort. Postoperative AKI occurred in 388 (72%) patients, including 162 (30%) severe AKI. The risk of 90 day mortality significantly increased in patients with severe-AKI. Seven independent predictors of severe AKI were found in the derivation cohort, including recipients' body mass index, history of diabetes, anaemia, preoperative inotropes, estimated glomerular filtration rate, cardiopulmonary bypass duration and intraoperative red blood cell transfusion. The occurrence of severe AKI increased gradually from the lowest to the highest of the four risk score groups in the derivation and validation cohort. The scoring prediction model showed a highly acceptable discriminating power for severe-AKI [C statistic: 0.76, 95% confidence interval (CI): 0.71-0.80 for derivation cohort; C statistic: 0.79, 95% CI: 0.71-0.89 for validation cohort].

CONCLUSIONS

A contemporary simple risk score based on available variables from patients undergoing HT can accurately discriminate the risk of severe AKI.

Prognostic significance of preoperative nutritional status for heart transplantation patients

BACKGROUND

The association between malnutrition and outcomes of heart transplantation (HTx) has not been well studied. The purpose of this article was to evaluate the prognostic value of three different nutrition indices in HTx, including CONUT (Controlling Nutritional Status), NRI (Nutritional Risk Index) and GNRI (Geriatric Nutritional Risk Index).

METHODS

A total of 438 patients who underwent THx from January 2015 to December 2020 were included in this study. The nutritional status of the patients was evaluated by CONUT, NRI and GNRI. Kaplan-Meier (KM) curves were constructed to compare the difference in overall survival (OS) between the normal and malnutrition groups in each index. Cox regression analysis was used to identify the independent risk factors of OS. The predictive power was compared by time-dependent ROC and time-dependent ccurves. Logistic regression model was used to evaluate the relationship between these three nutrition indices and postoperative clinical events.

RESULTS

336 (76.7%), 183 (43.8%), and 190 (43.4%) patients had malnutrition according to CONUT, NRI and GNRI calculations. 102 (23.3%) patients had died at the end of follow-up. After adjustment for confounding variables, multivariate Cox analysis showed that CONUT [HR 1.286 (95%CI 1.166 ~ 1.419); p < 0.001], NRI [HR 0.942 (95%CI 0.923 ~ 0.962); p < 0.001] and GNRI [HR 0.959 (95%CI 0.939 ~ 0.979); p < 0.001] were all independent predictors for OS. The predictive power of CONUT score was higher than that of NRI (p = 0.045) and GNRI (p < 0.001). Regarding the postoperative complications, multivariate logistic regression model showed that malnutrition assessed by CONUT [HR 1.156 (95%CI 1.032 ~ 1.294); p = 0.012] and NRI [HR 1.543 (95%CI 1.008 ~ 2.362); p = 0.046] was independent risk factors for posttransplant infections.

CONCLUSION

Poor nutritional status, as assessed by CONUT, NRI and GNRI, was associated with an increased risk of mortality after HTx. CONUT displayed the highest predictive power compared to the other two indices. CONUT and NRI were also independently associated with posttransplant infections.

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.

Impact of Preoperative Right Ventricular Function on Acute Renal Failure Development in Patients With Ventricular Assist Devices

Background Acute kidney injury (AKI) and acute renal failure contribute significantly to the high mortality and morbidity seen in patients with left ventricular assist devices (LVADs). The role of preoperative right ventricular function in the onset of acute renal failure remains an area of active investigation. This study aims to explore the correlation between preoperative right ventricular function and the development of AKI in patients undergoing LVAD implantation. Methods The demographic characteristics, comorbidities, and preoperative and postoperative data of 61 patients who underwent LVAD implantation between April 2012 and December 2021 were carefully documented. Transthoracic echocardiography was used to assess right ventricular function, with tricuspid annular plane systolic excursion (TAPSE) and right ventricular fractional area change (FAC) serving as key evaluation parameters. TAPSE values of ≥17 mm and FAC of ≥35% were considered indicative of normal right ventricular function. Based on these measurements, the study analyzed the association between preoperative right ventricular function and the incidence of postoperative AKI. Results When patients were grouped based on TAPSE values, significant differences emerged in ICU stay duration, hospital stay length, AKI development, and the need for renal replacement therapy post-AKI. Elevated preoperative serum creatinine levels (p = 0.01), older age (p = 0.02), higher body surface area (p = 0.024), and lower TAPSE values (p = 0.02) were identified as risk factors for postoperative AKI. However, no significant correlation was found between preoperative FAC values and AKI incidence in LVAD-implanted patients. Conclusions Preoperative TAPSE appears to be a more reliable predictor of postoperative renal dysfunction than FAC.

Impact of Age of Heart Transplant Program on Patient Survival and Post-Transplant Outcomes

BACKGROUND

The relationship between age of a heart transplant (HT) program and outcomes has not been explored.

METHODS

We performed a retrospective cohort analysis of the United Network for Organ Sharing database of all adult HTs between 2009 and 2019. For each patient, we created a variable that corresponded to program age: new (<5), developing (≥5 but <10) and established (≥10) years.

RESULTS

Of 20 997 HTs, 822 were at new, 908 at developing, and 19 267 at established programs. Patients at new programs were significantly more likely to have history of cigarette smoking, ischemic cardiomyopathy, and prior sternotomy. These programs were less likely to accept organs from older donors and those with a history of hypertension or cigarette use. As compared to patients at new programs, transplant patients at established programs had less frequent rates of treated rejection during the index hospitalization (HR 0.43 [95% CI, 0.36-0.53] p < 0.001) and at 1 year (HR 0.58 [95% CI, 0.49-0.70], p < 0.001), less frequently required pacemaker implantations (HR 0.50 [95% CI, 0.36-0.69], p < 0.001), and less frequently required dialysis (HR 0.66 [95% CI, 0.53-0.82], p < 0.001). However, there were no significant differences in short- or long-term survival between the groups (log-rank p = 0.24).

CONCLUSION

Patient and donor selection differed between new, developing, and established HT programs but had equivalent survival. New programs had increased likelihood of treated rejection, pacemaker implantation, and need for dialysis. Standardized post-transplant practices may help to minimize this variation and ensure optimal outcomes for all patients.

Perioperative Risk Factors of Acute Kidney Injury After Heart Transplantation and One-Year Clinical Outcomes: A Retrospective Cohort Study

OBJECTIVES

This study aimed to identify perioperative risk factors of acute kidney injury after heart transplantation and to evaluate 1-year clinical outcomes.

DESIGN

A retrospective single-center cohort study.

SETTING

At a university hospital.

PARTICIPANTS

All patients who underwent heart transplantation from January 2015 to December 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The authors recorded acute kidney injury after heart transplantation. One-year mortality and renal function also were recorded. Risk factors of acute kidney injury were evaluated using a multivariate logistic regression model. Long-term survival was compared between patients developing acute kidney injury and those who did not, using a log-rank test. Among 209 patients included in this study, 134 patients (64% [95% CI (58; 71)]) developed posttransplantation acute kidney injury. Factors independently associated with acute kidney injury were high body mass index (odds ratio [OR]: 1.18 [1.02-1.38] per kg/m2; p = 0.030), prolonged duration of cold ischemic period (OR: 1.11 [1.01-1.24] per 10 minutes; p = 0.039), and high dose of intraoperative dobutamine support (OR: 1.24 [1.06-1.46] per µg/kg/min; p = 0.008). At 1 year, patients who developed postoperative acute kidney injury had higher mortality rates (20% v 8%, p = 0.015). Among 172 survivors at 1 year, 82 survivors (48%) had worsened their renal function compared with preheart transplantation.

CONCLUSIONS

This study highlighted the high incidence of acute kidney injury after heart transplantation and its impact on patient outcomes. Risk factors such as body mass index, prolonged cold ischemic period duration, and level of inotropic support with dobutamine were identified, providing insights for preventive strategies.

Simultaneous heart-kidney transplant compared with heart transplant alone in patients with borderline renal function who are not dialysis dependent

OBJECTIVE

This study assessed characteristics and outcomes of patients who are not dependent on dialysis receiving simultaneous heart kidney transplantation versus heart transplantation alone (HTA) to identify optimal eGFR threshold where combined transplant strategy may be superior.

METHODS

This study retrospectively analyzed 7896 adult patients with estimated glomerular filtration rate (eGFR) <60 mL/minute from the United Network for Organ Sharing database who received HTA or simultaneous heart kidney transplant between 2005 and 2021, excluding those who received pretransplant dialysis. Subjects were further stratified into 3 groups based on chronic kidney disease stage at time of transplant: Stage 3A (eGFR 45-59 mL/minute; n = 5044), Stage 3B (eGFR 30-44 mL/minute; n = 2193), and Stage 4 or 5 (eGFR <30 mL/minute; n = 659). Outcomes of interest were all-cause mortality, cardiac allograft failure, and freedom from chronic dialysis or renal transplant following heart transplant.

RESULTS

Simultaneous heart kidney transplant and HTA recipients differed in various baseline characteristics. Simultaneous heart kidney transplant recipients with eGFR <45 mL/minute had greater short- and long-term overall survival and cardiac allograft survival compared with HTA, as well as greater long-term freedom from chronic dialysis or renal transplant. These results were consistent with both propensity matched analyses and multivariable Cox regression analysis of 10 year outcomes. Optimal cutoff value for pretransplant eGFR in predicting elevated risk of renal failure in recipients of heart transplant alone was found to be eGFR ∼45 mL/minute.

CONCLUSIONS

Similar to patients with eGFR <30 mL/minute, patients with eGFR 30 to 44 mL/minute who underwent simultaneous heart kidney transplant had superior outcomes compared with HTA, suggesting possible benefit of combined transplant strategy for this subset of heart transplant candidates.

Acute Kidney Injury After Heart Transplantation: Risk Factors and Clinical Outcomes

OBJECTIVE

Acute kidney injury (AKI) requiring renal-replacement therapy (RRT) after heart transplantation (OHT) is common and impairs outcomes. This study aimed to identify independent donor and recipient risk factors associated with RRT after OHT.

DESIGN

A retrospective data analysis.

SETTING

Data were collected from clinical routines in a maximum-care university hospital.

PARTICIPANTS

Patients who underwent OHT.

INTERVENTIONS

The authors retrospectively analyzed data from 264 patients who underwent OHT between 2012 and 2021; 189 patients were eligible and included in the final analysis.

MEASUREMENTS AND MAIN RESULTS

The mean age was 48.0 ± 12.3 years, and 71.4% of patients were male. Ninety (47.6%) patients were on long-term mechanical circulatory support (lt-MCS). Posttransplant AKI with RRT occurred in 123 (65.1%) patients. In a multivariate analysis, preoperative body mass index >25 kg/m² (odds ratio [OR] 4.74, p < 0.001), elevated preoperative creatinine levels (OR for each mg/dL increase 3.44, p = 0.004), administration of red blood cell units during transplantation procedure (OR 2.31, p = 0.041) and ischemia time (OR for each hour increase 1.77, p = 0.004) were associated with a higher incidence of RRT. The use of renin-angiotensin-aldosterone system blockers before transplantation was associated with a reduced risk of RRT (OR 0.36, p = 0.013). The risk of mortality was 6.9-fold higher in patients who required RRT (hazard ratio 6.9, 95% CI: 2.1-22.6 p = 0.001). Previous lt-MCS, as well as donor parameters, were not associated with RRT after OHT.

CONCLUSIONS

The implementation of guideline-directed medical therapy, weight reduction, minimizing ischemia time (ie, organ perfusion systems, workflow optimization), and comprehensive patient blood management potentially influences renal function and outcomes after OHT.

Determination of Risk Factors for Acute Kidney Injury In Orthotopic Cardiac Transplantation

BACKGROUND

In this study, we try to determine risk factors for acute kidney injury in orthotopic cardiac transplantation patients.

METHODS

Between February 2003 and December 2022, all cardiac transplantation patients were retrospectively reviewed. Finally, 102 patients enrolled in this study. Demographic data, comorbidities, preoperative cardiac catheterization parameters, preoperative and postoperative blood test results, intraoperative parameters, acute kidney injury developed or not, stage of acute kidney injury, and whether renal replacement therapy was required or not was recorded.

RESULTS

Of the 102 patients, 68 were male. Fifty-four of these patients developed acute kidney injury, and 31 required renal replacement therapy postoperatively. The mean age of developed acute kidney injury group (AKI+) was older than non-developed acute kidney injury group (non-AKI) (P = .01). The average body surface area of the AKI+ was 1.81 ± 0.32, whereas in non-AKI it was 1.57 ± 0.35 (P = .01). More patients were ex-smokers (P = .007) and had a history of hypertension (P= .011) in the AKI+ group. Preoperative serum creatinine was 1.12 ± 0.26 mg/dL in the AKI+ group and 0.82 ± 0.13 mg/dL in the non-AKI group (P = .02). The intraoperative urine output was 491.20 ± 276.48 mL for AKI+ and 676.45 ± 478.84 mL for the non-AKI group (P = .03).

CONCLUSIONS

Acute kidney injury development after cardiac transplantation is common. In our study, high body surface area, older age, ex-smoker, hypertension, low intraoperative urine output, and high preoperative serum creatinine levels were risk factors for acute kidney injury development in cardiac transplantation patients. Mortality and morbidity after cardiac transplantation might be reduced if acute kidney injury development can be lowered.

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.

Heart Transplantation-Postoperative Considerations

Heart transplantation (HT) remains the best treatment of patients with severe heart failure who are deemed to be transplant candidates. The authors discuss postoperative management of the HT recipient by system, emphasizing areas where care might differ from other cardiac surgery patients. Working together, critical care physicians, heart transplant surgeons and cardiologists, advanced practice providers, pharmacists, transplant coordinators, nursing staff, physical therapists, occupational therapists, rehabilitation specialists, nutritionists, health psychologists, social workers, and the patient and their loved ones partner to increase the likelihood of a successful outcome.

Perioperative Management of Heart Transplantation: A Clinical Review

In this clinical review, the authors summarize the perioperative management of heart transplant patients with a focus on hemodynamics, immunosuppressive strategies, hemostasis and hemorrage, and the prevention and treatment of infectious complications.

Dual-Organ Transplantation: Indications, Evaluation, and Outcomes for Heart-Kidney and Heart-Liver Transplantation: A Scientific Statement From the American Heart Association

Although heart transplantation is the preferred therapy for appropriate patients with advanced heart failure, the presence of concomitant renal or hepatic dysfunction can pose a barrier to isolated heart transplantation. Because donor organ supply limits the availability of organ transplantation, appropriate allocation of this scarce resource is essential; thus, clear guidance for simultaneous heart-kidney transplantation and simultaneous heart-liver transplantation is urgently required. The purposes of this scientific statement are (1) to describe the impact of pretransplantation renal and hepatic dysfunction on posttransplantation outcomes; (2) to discuss the assessment of pretransplantation renal and hepatic dysfunction; (3) to provide an approach to patient selection for simultaneous heart-kidney transplantation and simultaneous heart-liver transplantation and posttransplantation management; and (4) to explore the ethics of multiorgan transplantation.

Role of the Nephrologist in Non-Kidney Solid Organ Transplant (NKSOT)

BACKGROUND

Chronic kidney disease (CKD) is a common complication of a non-kidney solid organ transplant (NKSOT). Identifying predisposing factors is crucial for an early approach and correct referral to nephrology.

METHODS

This is a single-center retrospective observational study of a cohort of CKD patients under follow-up in the Nephrology Department between 2010 to 2020. Statistical analysis was performed between all the risk factors and four dependent variables: end-stage renal disease (ESKD); increased serum creatinine ≥50%; renal replacement therapy (RRT); and death in the pre-transplant, peri-transplant, and post-transplant periods.

RESULTS

74 patients were studied (7 heart transplants, 34 liver transplants, and 33 lung transplants). Patients who were not followed-up by a nephrologist in the pre-transplant (p < 0.027) or peri-transplant (p < 0.046) periods and those who had the longest time until an outpatient clinic follow-up (HR 1.032) were associated with a higher risk of creatinine increase ≥50%. Receiving a lung transplant conferred a higher risk than a liver or heart transplant for developing a creatinine increase ≥50% and ESKD. Peri-transplant mechanical ventilation, peri-transplant and post-transplant anticalcineurin overdose, nephrotoxicity, and the number of hospital admissions were significantly associated with a creatinine increase ≥50% and developing ESKD.

CONCLUSIONS

Early and close follow-up by a nephrologist was associated with a decrease in the worsening of renal function.

Incremental value of preoperative right ventricular function in predicting moderate to severe acute kidney injury after heart transplantation

Background

Acute kidney injury (AKI) commonly occurs after heart transplantation (HTx), but its association with preoperative right ventricular (RV) function remains unknown. Consequently, we aimed to determine the predictive value of preoperative RV function for moderate to severe AKI after HTx.

Materials and methods

From 1 January 2016 to 31 December 2019, all the consecutive HTx recipients in our center were enrolled and analyzed for the occurrence of postoperative AKI staged by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Conventional RV function parameters, including RV fractional area change (RVFAC) and tricuspid annular plane systolic excursion (TAPSE), were obtained. The primary endpoint was moderate to severe AKI (the KDIGO stage 2 or 3). The secondary endpoints included the impact of AKI on intensive care unit (ICU) mortality, in-hospital mortality, and 1-year mortality.

Results

A total of 273 HTx recipients were included in the study. Postoperative AKI occurred in 209 (77%) patients, including 122 (45%) patients in stage 1 AKI, 49 (18%) patients in stage 2 AKI, and 38 (14%) patients in stage 3 AKI. Patients with higher AKI stage had lower baseline estimated glomerular filtration rate (eGFR), more frequent diabetes, higher right atrial pressure (RAP), longer cardiopulmonary bypass (CPB) duration, more perioperative red blood cell (RBC) transfusions, and worse preoperative RV function. A multivariate logistic regression model incorporating previous diabetes mellitus [odds ratio (OR): 2.21; 95% CI: 1.06–4.61; P = 0.035], baseline eGFR (OR: 0.99; 95% CI: 0.97–0.10; P = 0.037), RAP (OR: 1.05; 95% CI: 1.00–1.10; P = 0.041), perioperative RBC (OR: 1.18; 95% CI: 1.08–1.28; P < 0.001), and TAPSE (OR: 0.84; 95% CI: 0.79–0.91; P < 0.001) was established to diagnose moderate to severe AKI more accurately [the area under the curve (AUC) = 79.8%; Akaike information criterion: 274].

Conclusion

Preoperative RV function parameters provide additional predicting value over clinical and hemodynamic parameters, which are imperative for risk stratification in patients with HTx at higher risk of AKI.

Machine learning to predict post-operative acute kidney injury stage 3 after heart transplantation

BACKGROUND

Acute kidney injury (AKI) stage 3, one of the most severe complications in patients with heart transplantation (HT), is associated with substantial morbidity and mortality. We aimed to develop a machine learning (ML) model to predict post-transplant AKI stage 3 based on preoperative and perioperative features.

METHODS

Data from 107 consecutive HT recipients in the provincial center between 2018 and 2020 were included for analysis. Logistic regression with L2 regularization was used for the ML model building. The predictive performance of the ML model was assessed using the area under the curve (AUC) in tenfold stratified cross-validation and was compared with that of the Cleveland-clinical model.

RESULTS

Post-transplant AKI occurred in 76 (71.0%) patients including 15 (14.0%) stage 1, 18 (16.8%) stage 2, and 43 (40.2%) stage 3 cases. The top six features selected for the ML model to predicate AKI stage 3 were serum cystatin C, estimated glomerular filtration rate (eGFR), right atrial long-axis dimension, left atrial anteroposterior dimension, serum creatinine (SCr) and FVII. The predictive performance of the ML model (AUC: 0.821; 95% confidence interval [CI]: 0.740-0.901) was significantly higher compared with that of the Cleveland-clinical model (AUC: 0.654; 95% [CI]: 0.545-0.763, p < 0.05).

CONCLUSIONS

The ML model, which achieved an effective predictive performance for post-transplant AKI stage 3, may be helpful for timely intervention to improve the patient's prognosis.

Acute myocardial infarction in heart transplant recipients: An 18-year national study

Among 11,622,528 acute myocardial infarction (AMI) hospitalizations, 892 had a history of heart transplantation (HT). In comparison to AMI admissions without HT, those with prior HT were more frequently complicated with cardiac arrest (8.3 % vs 5.0 %, p < 0.001), acute non-cardiac organ failure (17.4 % vs 9.4 %) (p < 0.001), lower rates of coronary angiography (55.4 % vs 63.6 %, p < 0.001), comparable rates of percutaneous coronary intervention (38.8 % vs 41.5 %, p = 0.10), higher rates of pulmonary artery catheterization (2.7 % vs 1.1 %, p < 0.001), invasive mechanical ventilation and acute hemodialysis compared to AMI admissions without HT. Compared to AMI admissions without HT, prior HT recipients had higher in-hospital mortality (11.8 % vs 6.2 %, adjusted odds ratio 2.87 [95 % CI 2.23-3.70]; p < 0.001).

Risk factors of renal replacement therapy after heart transplantation: a retrospective single-center study

BACKGROUND

Acute kidney injury (AKI) and renal replacement therapy (RRT) are common after heart transplantation (HT). The need for RRT has been reported to be one of the most important predictors of a poor prognosis after HT. Therefore, it is important to early identify risk factors of RRT after HT. However, in the heart transplantation setting, the risk factors are less well studied, and some of the conclusions are controversial. This study aimed to identify the clinical predictors of RRT after HT.

METHODS

This single-center, retrospective study from January 2010 to June 2021 analyzed risk factors (pre-, intra-, and postoperative characteristics) of 163 patients who underwent HT. The endpoint of the study was RRT within 7 days of HT. Risk factors were analyzed by multivariable logistic regression models.

RESULTS

Fifty-five (33.74%) recipients required RRT within 7 days of HT. Factors independently associated with RRT after HT were as follows: a baseline estimated glomerular filtration rate (eGFR) <60 mL/min per 1.73 m² [odds ratio (OR) =3.123; 95% confidence interval (CI): 1.183-8.244; P=0.022], a dose of intraoperative methylprednisolone >10 mg/kg (OR =3.197; 95% CI: 1.290-7.923; P=0.012), the use of mechanical circulatory support (MCS) during surgery (OR =4.903; 95% CI: 1.628-14.766; P=0.005), a cardiopulmonary bypass (CPB) time ≥5 hours (OR =3.929; 95% CI: 1.222-12.634; P=0.022), and postoperative serum total bilirubin (TBIL) ≥60 umol/L (OR =5.105; 95% CI: 1.868-13.952; P=0.001). Protective factors were higher postoperative serum albumin (OR =0.907; 95% CI: 0.837-0.983; P=0.017) and higher postoperative left ventricular ejection fraction (LVEF) (OR =0.908; 95% CI: 0.838-0.985; P=0.020).

CONCLUSIONS

A low preoperative eGFR, a high intraoperative dose of methylprednisolone, a long CPB time, the use of mechanical circulatory support, and a high postoperative TBIL were risk factors for RRT after HT. While a high postoperative serum albumin level and a high left ventricular ejection fraction were protective factors. Understanding these risk factors may help us identify high-risk patients and intervene early.

Impact of a clinical pathway on acute kidney injury in patients undergoing heart transplant

BACKGROUND

To evaluate the impact of a clinical pathway on the incidence and severity of acute kidney injury in patients undergoing heart transplant.

METHODS

This was a 2.5-year retrospective evaluation using 3 years of historical controls within a cardiac intensive care unit in an academic children's hospital. Patients undergoing heart transplant between May 27, 2014, and April 5, 2017 (pre-pathway) and May 1, 2017, and November 30, 2019 (pathway) were included. The clinical pathway focused on supporting renal perfusion through hemodynamic management, avoiding or delaying nephrotoxic medications, and providing pharmacoprophylaxis against AKI.

RESULTS

There were 57 consecutive patients included. There was an unadjusted 20% reduction in incidence of any acute kidney injury (p = .05) and a 17% reduction in Stage 2/3 acute kidney injury (p = .09). In multivariable adjusted analysis, avoidance of Stage 2/3 acute kidney injury was independently associated with the clinical pathway era (AOR -1.3 [95% CI -2.5 to -0.2]; p = .03), achieving a central venous pressure of or less than 12 mmHg (AOR -1.3 [95% CI -2.4 to -0.2]; p = .03) and mean arterial pressure above 60 mmHg (AOR -1.6 [95% CI -3.1 to -0.01]; p = .05) in the first 48 h post-transplant, and older age at transplant (AOR - 0.2 [95% CI -0.2 to -0.06]; p = .002).

CONCLUSIONS

This report describes a renal protection clinical pathway associated with a reduction in perioperative acute kidney injury in patients undergoing heart transplant and highlights the importance of normalizing perioperative central venous pressure and mean arterial blood pressure to support optimal renal perfusion.

Incidence and long-term outcome of heart transplantation patients who develop postoperative renal failure requiring dialysis

BACKGROUND

Acute renal failure requiring dialysis after heart transplantation remains a significant clinical issue because of its increasing incidence. We aimed to investigate its time trends, clinical predictors, and long-term outcomes.

METHODS

Adult heart transplantation recipients registered in the United Network for Organ Sharing registry between 2009 and 2020 were identified. The patients were grouped according to the requirement for dialysis in the postoperative heart transplantation period. The independent risk predictors were identified, and the association between post-heart transplantation renal failure requiring dialysis and long-term mortality accounting for re-transplantation was investigated.

RESULTS

A total of 28,170 patients were included in the study, of which 3,371 (12%) required dialysis immediately post-heart transplantation. The incidence increased from 7.9% to 13.9% during the study period. Longer ischemic time, serum creatinine at transplantation >1.2 mg/dL, prior cardiac surgery, higher recipient body mass index, support of mechanical ventilation or extracorporeal membrane oxygenation, and history of congenital heart disease or restrictive/hypertrophic cardiomyopathy were its predictors (all p < 0.05). Patients on posttransplant dialysis had a higher risk of all-cause mortality (adjusted hazard ratio [aHR]: 5.2, 95% CI: 4.7-5.7, p < 0.001), 30 day mortality (aHR: 7.7, 95% CI: 6.3-9.6, p < 0.001) and 1 year mortality (aHR: 7.5, 95% CI: 6.6-8.6, p < 0.001). Post-transplant dialysis was associated with a risk of treated rejection at 1 year.

CONCLUSION

Acute renal failure requiring dialysis after heart transplantation is associated with significantly worse 30 day and long-term mortalities, and thus, early identification of high-risk patients is crucial to prevent severe renal complications.

Current State of Multiorgan Transplantation and Implications for Future Practice and Policy

The incidence of kidney dysfunction has increased in liver transplant and heart transplant candidates, reflecting a changing patient population and allocation policies that prioritize the most urgent candidates. A higher burden of pretransplant kidney dysfunction has resulted in a substantial rise in the utilization of multiorgan transplantation (MOT). Owing to a shortage of available deceased donor kidneys, the increased use of MOT has the potential to disadvantage kidney-alone transplant candidates, as current allocation policies generally provide priority for MOT candidates above all kidney-alone transplant candidates. In this review, the implications of kidney disease in liver transplant and heart transplant candidates is reviewed, and current policies used to allocate organs are discussed. Important ethical considerations pertaining to MOT allocation are examined, and future policy modifications that may improve both equity and utility in MOT policy are considered.

Urinary Cell-Cycle Arrest Biomarkers as Early Predictors of Acute Kidney Injury After Ventricular Assist Device Implantation or Cardiac Transplantation

OBJECTIVES

Acute kidney injury (AKI) remains a leading source of morbidity and mortality after cardiothoracic surgery. Insulin-like growth factor-binding protein 7 (IGFBP7), and tissue inhibitor of metalloproteinases-2 (TIMP-2), are novel early-phase renal biomarkers that have been validated as sensitive predictors of AKI. Here the authors studied the efficacy of these biomarkers for predicting AKI after left ventricular assist device (LVAD) implantation and cardiac transplantation.

DESIGN/SETTING/PARTICIPANTS/INTERVENTIONS

This was a prospective study of 73 patients undergoing LVAD implantation (n = 37) or heart transplant (n = 36) from 2016 to 2017 at the authors' center. TIMP-2 and IGFBP7 were measured with the NephroCheck Test on urine samples before surgery and one-to-six hours after surgery. NephroCheck scores were assessed as predictors of moderate/severe AKI (Kidney Disease International Global Outcomes 2/3 creatinine criteria) within 48 hours of surgery, and the association with survival to one year was investigated.

MEASUREMENTS AND MAIN RESULTS

The LVAD and transplant cohorts overall were similar in demographics and baseline creatinine (p > 0.05), with the exception of having more African-American patients in the LVAD arm (p = 0.003). Eleven (30%) LVAD and 16 (44%) transplant patients developed moderate/severe AKI. Overall, AKI was associated with postsurgery NephroCheck (odds ratio [95% confidence interval] for 0.1 mg/dL increase: 1.36 [1.04-1.79]; p = 0.03), but not with baseline NephroCheck (p = 0.92). When analyzed by cohort, this effect remained for LVAD (1.68 [1.05-2.71]; p = 0.03) but not for transplant (p = 0.15). Receiver operating characteristic analysis showed postoperative NephroCheck to be superior to baseline creatinine in LVAD (p = 0.046). Furthermore, an increase of 0.1 mg/dL in postoperative NephroCheck was associated with a 10% increase in the risk of mortality (adjusted hazard ratio: 1.11 [1.01-1.21]; p = 0.04) independent of age and body mass index.

CONCLUSION

Assessment of TIMP-2 and IGFBP7 within six hours after surgery appeared effective at predicting AKI in patients with LVADs. Larger studies are warranted to validate these findings.

Early post-operative acute kidney injury after cardiac transplantation: Incidence and predictive factors

BACKGROUND

Heart transplantation, as a therapeutic option for patients with advanced heart failure, possesses a high rate of morbidity and mortality. One of the complications associated with this procedure is the development of postoperative acute kidney injury (AKI) MATERIAL AND METHODS: We aimed to evaluate the incidence of early postoperative AKI and the need for continuous renal replacement therapy (RRT) after heart transplantation. Data of 126 patients who underwent heart transplantation from January 2015 to November 2019 were collected. Statistical analysis was performed to identify the predictors of postoperative AKI.

RESULTS

Out of 126 patients, 74 (58.7 %) developed AKI and 13 (10%) required RRT after transplant. Independent predictors of AKI are shown to be factors associated with surgical procedures such as graft ischemic time as were previous cardiac operation, administered Voluven (starch) dose > 400 ml and transfusion of more than four blood units.

CONCLUSION

Our findings suggest that modifiable factors exist that can affect the risk of developing AKI following heart transplantation. This article is protected by copyright. All rights reserved.

Need for improvements in simultaneous heart-kidney allocation: The limitation of pretransplant glomerular filtration rate

The incidence of simultaneous heart-kidney transplant (SHK) has increased markedly in the last 15 years. There are no universally agreed upon indications for SHK vs. heart alone (HA) transplant, and center evaluation processes vary widely. We utilized Scientific Registry of Transplant Recipients data from 2003 to 2017 to quantify changes in the practice of SHK, examine the survival of SHK vs. HA, and identify patients with marginal benefit from SHK. We used Kaplan-Meier curves and Cox proportional hazards to assess differences in survival. The incidence of SHK increased more than fourfold between 2003 and 2017 from 1.6% to 6.6% of total hearts transplanted, while the proportion of dialysis-dependent patients undergoing SHK has remained constant. SHK was associated with increased survival in dialysis-dependent patients (Median Survival SHK: 12.6 vs. HA: 7.1 years p < .0001) but not with nondialysis-dependent patients (Median Survival SHK: 12.5 vs. HA 12.3, p = .24). The marginal effect of SHK in decreasing the hazard of death diminished with increasing eGFR. Delayed graft function occurred in 26% of SHK recipients. Posttransplant chronic dialysis was similar for both operations (6.4% of HA and 6.0% of SHK). Further study is needed to define patients who benefit from SHK.

Acute kidney injury post-heart transplant: An analysis of peri-operative risk factors

Acute kidney injury is a common complication following heart transplantation, and the factors contributing to acute kidney injury are not well understood. We conducted a retrospective cohort study evaluating patients who underwent heart transplantation between 2009 and 2016 at a single institution. The primary endpoint was incidence of acute kidney injury as defined by Kidney Disease Improving Global Outcomes criteria. Secondary endpoints included 30-day hospital readmission, 30-day mortality, and 1-year mortality. A total of 228 heart transplant patients were included in the study for analysis. In total, 145 (64%) developed acute kidney injury, where 43 (30%) were classified as stage I, 28 (19%) as stage II, and 74 (51%) as stage III. Risk factors found to be associated with the presence of acute kidney injury included increased use of vasopressors and inotropes post-transplant. Protective factors included cardiopulmonary bypass time <170 min. Acute kidney injury was found to be associated with increased 30-day and 1-year mortality.

Acute kidney injury in renal transplant recipients undergoing cardiac surgery

BACKGROUND

Acute kidney injury (AKI) is a key risk factor for chronic kidney disease in the general population, but has not been investigated in detail among renal transplant recipients (RTRs). We investigated the incidence, severity and risk factors for AKI following cardiac surgery among RTRs compared with non-RTRs with otherwise similar clinical characteristics.

METHODS

We conducted a retrospective cohort study of RTRs (n = 83) and non-RTRs (n = 83) who underwent cardiac surgery at two major academic medical centers. Non-RTRs were matched 1:1 to RTRs by age, preoperative (preop) estimated glomerular filtration rate and type of cardiac surgery. We defined AKI according to Kidney Disease: Improving Global Outcomes criteria.

RESULTS

RTRs had a higher rate of AKI following cardiac surgery compared with non-RTRs [46% versus 28%; adjusted odds ratio 2.77 (95% confidence interval 1.36-5.64)]. Among RTRs, deceased donor (DD) versus living donor (LD) status, as well as higher versus lower preop calcineurin inhibitor (CNI) trough levels, were associated with higher rates of AKI (57% versus 33% among DD-RTRs versus LD-RTRs; P = 0.047; 73% versus 36% among RTRs with higher versus lower CNI trough levels, P = 0.02). The combination of both risk factors (DD status and higher CNI trough level) had an additive effect (88% AKI incidence among patients with both risk factors versus 25% incidence among RTRs with neither risk factor, P = 0.004).

CONCLUSIONS

RTRs have a higher risk of AKI following cardiac surgery compared with non-RTRs with otherwise similar characteristics. Among RTRs, DD-RTRs and those with higher preop CNI trough levels are at the highest risk.

Care for the organ transplant recipient on the intensive care unit

All transplant recipients receive tacrolimus, mycophenolate and glucocorticoids and these drugs have many side-effects and drug-drug interactions. Common complications include surgical complications, infections, rejection and acute kidney injury. Infections as CMV and PJP can be prevented with prophylactic treatment. Given the complexity of organ transplant recipients a multi-disciplinary team of intensivists, surgeons, pharmacists and transplant specialists is essential. After heart transplantation a temporary pacemaker is required until the conduction system recovers. Stiffening of the heart and increased cardiac markers indicate rejection. An endomyocardial biopsy is performed via the right jugular vein, necessitating its preservation. For lung transplant patients, early intervention for aspiration is warranted to prevent chronic rejection. Risk of any infection is high, requiring active surveillance and intensive treatment, mainly of fungal infections. The liver is immunotolerant requiring lower immunosuppression. Transplantation surgery is often accompanied by massive blood loss and coagulopathy. Other complications include portal vein or hepatic artery thrombosis and biliary leakage or stenosis. Kidney transplant recipients have a high risk of cardiovascular disease and posttransplant anemia should be treated liberally. After postmortal transplantation, delayed graft function is common and dialysis is continued. Ureteral anastomosis complications can be diagnosed with ultrasound.

Acute Kidney Injury After Heart Transplant: The Importance of Pulmonary Hypertension

OBJECTIVE

To determine whether relative pulmonary hypertension (PH), defined as the ratio of mean arterial pressure to mean pulmonary artery pressure, is associated with severe acute kidney injury (AKI) after heart transplant (HT).

DESIGN

An institutional review board-approved retrospective observational study.

SETTING

Tertiary care university hospital.

PARTICIPANTS

A total of 184 consecutive adult patients who underwent HT between January 2009 and December 2017 were included, and were followed up through December 2019. Using the Kidney Disease: Improving Global Outcomes classification, recipients were categorized into two groups: patients who developed stage 3 AKI (severe AKI) and those with minor or without AKI (nonsevere AKI) within seven days after transplant.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of the included patients, 83.2% developed AKI, in whom 40.8%, 19.6%, and 22.8% were stage 1, 2, and 3, respectively. With use of the multivariate logistic regression analysis, independent risk factors for stage 3 AKI post-HT included preoperative relative PH (odds ratio [OR]: 1.62, 95% confidence interval [95% CI]: 1.05-2.49, p = 0.028), central venous-to-pulmonary capillary wedge pressure ratio ≥0.86 (OR: 3.59, 95% CI: 1.13-11.43, p = 0.030), and postoperative right ventricular dysfunction (OR: 3.63, 95% CI: 1.50-8.75, p = 0.004). Conversely, preoperative estimated glomerular filtration rate (OR: 0.99, 95% CI: 0.97-1.00, p = 0.143) was not related to the development of stage 3 AKI post-HT.

CONCLUSIONS

Preoperative relative PH, central venous-to-pulmonary capillary wedge pressure ratio, and postoperative right ventricular failure by echocardiographic assessment were associated with severe AKI post-HT.

Role of Renal Replacement Therapy During the Peri-Transplant Period of Heart Transplantation

Background

Heart transplantation (HT) is the most useful treatment modality for heart failure. Although several studies have reported the impact of acute kidney injury (AKI) on clinical outcomes after transplantation, little is known about the impact of peri-transplant renal replacement therapy (RRT) on clinical outcomes. We compared the clinical outcomes according to RRT use status among patients with AKI during the peri-transplant period.

Material/Methods

The medical records of 21 patients who underwent HT from January 2006 to May 2019 were reviewed. We assessed the heart failure cause, comorbidities, immunosuppressant type, requirement for extracorporeal membrane oxygenation, AKI incidence, and cardiac and renal functions over time. The patients were divided into 3 groups: those without AKI (non-AKI group, n=6), those who underwent perioperative RRT (RRT group, n=10), and those who did not undergo RRT (non-RRT group, n=5).

Results

The most common cause of HT was dilated cardiomyopathy (52.4%). Fifteen patients (71.4%) experienced AKI during the peri-transplant period. Among them, 9 (90%) in the RRT group underwent continuous RRT and only 1 (10%) underwent intermittent hemodialysis. Until 6 months after HT, the renal function of the RRT group was worse than that of the non-RRT group (estimated glomerular filtration rate 44.2 vs. 69.2 mL/min/1.73 m², P=0.015), but the differences dissipated by 9 months. Finally, all patients, even in the RRT group, withdrew from dialysis.

Conclusions

RRT during the peri-transplant period in HT may be a good bridge therapy for renal function recovery in patients with cardiorenal AKI.

Incidence, risk factors and clinical outcomes of acute kidney injury after heart transplantation: a retrospective single center study

Objectives

This study aimed to identify the incidence rate of Acute kidney injury (AKI) in our center and predict in-hospital mortality and long-term survival after heart transplantation (HTx).

Methods

This single-center, retrospective study from October 2009 and March 2020 analyzed the pre-, intra-, and postoperative characteristics of 95 patients who underwent HTx. AKI was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Risk factors were analyzed by multivariable logistic regression models. The log-rank test was used to compare long-term survival.

Results

Thirty-three (34.7%) patients developed AKI. The mortality in hospital in HTx patients with and without AKI were 21.21 and 6.45%, respectively (P < 0.05). Recipients in AKI who required renal replacement therapy (RRT) had a hospital mortality rate of 43.75% compared to 6.45% in those without AKI or RRT (P < 0.0001). A long cardiopulmonary bypass (CPB) time (OR:11.393, 95% CI: 2.183 to 59.465, P = 0.0039) was positively related to the occurrence of AKI. A high intraoperative urine volume (OR: 0.031, 95% CI: 0.005 to 0.212, P = 0.0004) was negatively correlated with AKI. AKI requiring RRT (OR, 11.348; 95% CI, 2.418–53.267, P = 0.002) was a risk factor for mortality in hospital. Overall survival in patients without AKI at 1 and 3 years was not different from that in patients with AKI (P = 0.096).

Conclusions

AKI is common after HTx. AKI requiring RRT could contribute powerful prognostic information to predict mortality in hospital. A long CPB time and low intraoperative urine volume are associated with the occurrence of AKI.

Long-Term Outcomes and Risk Factors of Renal Failure Requiring Dialysis after Heart Transplantation: A Nationwide Cohort Study

Acute kidney injury and renal failure are common after heart transplantation. We retrospectively reviewed a national cohort and identified 1129 heart transplant patients. Patients receiving renal replacement therapy after heart transplantation were grouped into the dialysis cohort. The long-term survival and risk factors of dialysis were investigated. Patients who had undergone dialysis were stratified to early or late dialysis for subgroup analysis. The mean follow-up was five years, the incidence of dialysis was 28.4% (21% early dialysis and 7.4% late dialysis). The dialysis cohort had higher overall mortality compared with the non-dialysis cohort. The hazard ratios of mortality in patients with dialysis were 3.44 (95% confidence interval (CI), 2.73–4.33) for all dialysis patients, 3.58 (95% CI, 2.74–4.67) for early dialysis patients, and 3.27 (95% CI, 2.44–4.36; all p < 0.001) for late dialysis patients. Patients with diabetes mellitus, chronic kidney disease, acute kidney injury, and coronary artery disease were at higher risk of renal failure requiring dialysis. Cardiomyopathy, hepatitis B virus infection, and hyperlipidemia treated with statins were associated with a lower risk of renal dysfunction requiring early dialysis. The use of Sirolimus and Mycophenolate mofetil was associated with a lower incidence of late dialysis. Renal dysfunction requiring dialysis after heart transplantation is common in Taiwan. Early and late dialysis were both associated with an increased risk of mortality in heart transplant recipients.

The impact of severe acute kidney injury requiring renal replacement therapy on survival and renal function of heart transplant recipients - a UK cohort study

Severe acute kidney injury (AKI), defined as requiring renal replacement therapy (RRT), is associated with higher mortality postheart transplantation, but its long-term renal consequences are not known. Anonymized data of 3365 patients, who underwent heart transplantation between 1995 and 2017, were retrieved from the UK Transplant Registry. Multivariable binary logistic regression was performed to identify risk factors for severe AKI requiring RRT, Kaplan-Meier analysis to compare survival and renal function deterioration of the RRT and non-RRT groups, and multivariable Cox regression model to identify predicting factors of mortality and end-stage renal disease (ESRD). 26.0% of heart recipients received RRT post-transplant. The RRT group has lower survival rates at all time points, especially in the immediate post-transplant period. However, conditional on 3 months survival, older age, diabetes and coronary heart disease, but not post-transplant RRT, were the risk factors for long-term survival. The predicting factors for ESRD were insulin-dependent diabetes, renal function at transplantation, eGFR decline in the first 3 months post-transplant, post-transplant severe AKI and transplantation era. Severe AKI requiring RRT post-transplant is associated with worse short-term survival, but has no impact on long-term mortality. It also accelerates recipients' renal function deterioration in the long term.

Short-term mechanical circulatory support devices as bridge to heart transplantation: A prospective single-center experience in Argentina

BACKGROUND

Patients with cardiogenic shock may require hemodynamic stabilization with short-term mechanical circulatory support devices (ST-MCS) such as extracorporeal membrane oxygenation (ECMO) and centrifugal pump (CP) as bridge to transplantion (BTT). This study aimed to describe ECMO and CP during BTT and after heart transplant.

METHODS

A cohort of patients on ECMO or CP as BTT between April 2006 and April 2018 in a single hospital.

RESULTS

Thirty-seven consecutive patients with ECMO (n = 14) or CP (n = 23) were included. Acute kidney injury was more prevalent during CP (28.6% vs 69.6%, P = .02). There were no differences in stroke, thrombosis, sepsis, or vasoplegia. Bleeding (0% vs 56.5%, P = .0003) and reoperation (0% vs 47.8%, P = .002) were more frequent in CP group as well as mortality (0 vs 7 [30.4%], P = .03). The remaining 30 patients (81.1%) underwent heart transplantation, without differences in primary graft dysfunction, vasoplegia, reoperation for bleeding, or hospital stay. Mortality was 23.3% at 30 days, similar in both groups, with no further deaths at median follow-up of 44.2 months.

CONCLUSIONS

In patients with cardiogenic shock, ST-MCS with ECMO or CP as BTT are a lifesaving approach allowing successful transplantation in the majority of cases, with good short- and long-term survival.

Efficacy of Early Goal-Directed Renal Replacement Therapy for the Treatment of Acute Kidney Injury After Heart Transplantation: A Single-Center 10-Year Experience

OBJECTIVE

Acute kidney injury (AKI) after heart transplantation is a common and serious complication. The present study aimed to evaluate the efficacy of early goal-directed renal replacement therapy (GDRRT) for the treatment of AKI after heart transplantation.

DESIGN

Retrospective, observational study.

SETTING

Grade A tertiary hospital that performs more than 4,000 cardiac surgery procedures per year.

PARTICIPANTS

Patients who underwent heart transplantation with postoperative AKI and received renal replacement therapy from January 2008 to June 2018.

INTERVENTIONS

Patients were divided into a late GDRRT group (LGDRRT) (January 2008-September 2012) or an early GDRRT group (EGDRRT) (October 2012-June 2018).

RESULTS

The LGDRRT group comprised 30 patients, and the EGDRRT group comprised 46 patients. Duration between surgery to renal replacement therapy (RRT) initiation in the EGDRRT group was significantly shorter than in the LGDRRT group (1 [1-3] d v 2 [2-3] d; p = 0.020). The in-hospital mortality in the EGDRRT group was significantly lower than that of the LGDRRT group (39.1% v 63.3%; p = 0.039). After multivariate adjustment for confounding factors, the hazard ratio for death in the LGDRRT group relative to the EGDRRT group was 2.028 (95% confidence interval 1.072-3.655; p = 0.048). Length of intensive care unit and hospital stays in the EGDRRT group was significantly shorter than that of the LGDRRT group (26 ± 18 d v 38 ± 20 d; p = 0.008 and 38 ± 33 d v 64 ± 45 d; p = 0.005, respectively). The complete renal recovery rate was much greater in the EGDRRT group than that of the LGDRRT group (50.0% v 20.0%; p < 0.001). Serum creatinine at discharge was significantly less in the EGDRRT group than that of the LGDRRT group (134.8 ± 97.3 μmol/L v 220.7 ± 113.6 μmol/L; p < 0.001). Cost of RRT in the EGDRRT group was significantly less than that of the LGDRRT group (0.54 ± 0.10 v. 0.63 ± 0.11 ten thousand USD; p < 0.001).

CONCLUSIONS

For heart transplantation recipients with AKI, EGDRRT can reduce the in-hospital mortality and the length of intensive care unit and hospital stays, improve the complete renal recovery rate, and reduce the cost of RRT.

Acute Kidney Injury in Patients Undergoing Cardiac Transplantation: A Meta-Analysis

Background: Acute kidney injury (AKI) is a common complication following solid-organ transplantation. However, the epidemiology of AKI and mortality risk of AKI among patients undergoing cardiac transplantation is not uniformly described. We conducted this study to assess the incidence of AKI and mortality risk of AKI in adult patients after cardiac transplantation. Methods: A systematic review of EMBASE, MEDLINE, and Cochrane Databases was performed until June 2019 to identify studies evaluating the incidence of AKI (by standard AKI definitions), AKI requiring renal replacement therapy (RRT), and mortality risk of AKI in patients undergoing cardiac transplantation. Pooled AKI incidence and mortality risk from the included studies were consolidated by random-effects model. The protocol for this study is registered with PROSPERO (no. CRD42019134577). Results: 27 cohort studies with 137,201 patients undergoing cardiac transplantation were identified. Pooled estimated incidence of AKI and AKI requiring RRT was 47.1% (95% CI: 37.6-56.7%) and 11.8% (95% CI: 7.2-18.8%), respectively. The pooled ORs of hospital mortality and/or 90-day mortality among patients undergoing cardiac transplantation with AKI and AKI requiring RRT were 3.46 (95% CI, 2.40-4.97) and 13.05 (95% CI, 6.89-24.70), respectively. The pooled ORs of 1-year mortality among patients with AKI and AKI requiring RRT were 2.26 (95% CI, 1.56-3.26) and 3.89 (95% CI, 2.49-6.08), respectively. Conclusion: Among patients undergoing cardiac transplantation, the incidence of AKI and severe AKI requiring RRT are 47.1% and 11.8%, respectively. AKI post cardiac transplantation is associated with reduced short term and 1-year patient survival.

Controversies in the Postoperative Management of the Critically Ill Heart Transplant Patient

Heart transplant recipients are susceptible to a number of complications in the immediate postoperative period. Despite advances in surgical techniques, mechanical circulatory support (MCS), and immunosuppression, evidence supporting optimal management strategies of the critically ill transplant patient is lacking on many fronts. This review identifies some of these controversies with the aim of stimulating further discussion and development into these gray areas.

The aftermath of acute kidney injury: a narrative review of long-term mortality and renal function

Acute kidney injury (AKI) is a frequent complication of hospitalization and is associated with an increased risk of chronic kidney disease (CKD), end-stage renal disease (ESRD), and mortality. While AKI is a known risk factor for short-term adverse outcomes, more recent data suggest that the risk of mortality and renal dysfunction extends far beyond hospital discharge. However, determining whether this risk applies to all patients who experience an episode of AKI is difficult. The magnitude of this risk seems highly dependent on the presence of comorbid conditions, including cardiovascular disease, hypertension, diabetes mellitus, preexisting CKD, and renal recovery. Furthermore, these comorbidities themselves lead to structural renal damage due to multiple pathophysiological changes, including glomeruloscleroses and tubulointerstitial fibrosis, which can lead to the loss of residual capacity, glomerular hyperfiltration, and continued deterioration of renal function. AKI seems to accelerate this deterioration and increase the risk of death, CDK, and ESRD in most vulnerable patients. Therefore, we strongly advocate adequate hemodynamic monitoring and follow-up in patients susceptible to renal dysfunction. Additionally, other potential renal stressors, including nephrotoxic medications and iodine-containing contrast fluids, should be avoided. Unfortunately, therapeutic interventions are not yet available. Additional research is warranted and should focus on the prevention of AKI, identification of therapeutic targets, and provision of adequate follow-up to those who survive an episode of AKI.

Renal Complications Following Lung Transplantation and Heart Transplantation

Renal complications are common following heart and/or lung transplantation and lead to increased morbidity and mortality. Renal dysfunction is also associated with increased mortality for patients on the transplant wait list. Dialysis dependence is a relative contraindication for heart or lung transplantation at most centers, and such patients are often listed for a simultaneous kidney transplant. Several factors contribute to the impaired renal function in patients undergoing heart and/or lung transplantation, including the interplay between cardiopulmonary and renal hemodynamics, complex perioperative issues, and exposure to nephrotoxic medications, mainly calcineurin inhibitors.

Acute kidney injury after non-cardiovascular surgery: risk factors and impact on development of chronic kidney disease and long-term mortality

OBJECTIVE

To identify factors associated with acute kidney injury (AKI) and its progression to chronic kidney disease (CKD) in a non-cardiac/non-vascular surgery setting.

METHODS

This study examined the Veterans Affairs Surgical Quality database for surgical entries between 2000-2014. Demographics, comorbidities, laboratory findings and hospital outcomes were assessed. The primary end-point was the occurrence of AKI, defined as an increase of ≥0.3 mg/dL, 48 h post-operatively. Major adverse cardiac event (MACE) was defined as the composite first occurrence of myocardial infarction, cardiac arrest, and death in 30 days (secondary end-point) and was compared between two groups. Rates of progression to CKD in 1 year and long-term survival were examined.

MAIN OUTCOME MEASURES

Occurrence of AKI 48 h post-operatively.

RESULTS

AKI was documented in 8.5% of patients. Age, diabetes, and chronic obstructive pulmonary disease, chronic kidney disease, platelet count, serum albumin level, and duration of surgery were identified as independent predictors of AKI. In total, 6.4% patients developed MACE, which was more frequent in patients with AKI (p < .001). Age and pre-operative hematocrit <30% were independent predictors of progression to CKD. Pre-operative hematocrit with a cut-off value of 30% was the only modifiable factor to predict the long-term survival.

CONCLUSION

Development of AKI is associated with increased odds of various post-operative complications and long-term renal insufficiency and mortality.

Patterns of kidney injury in pediatric nonkidney solid organ transplant recipients

The incidence of acute kidney injury (AKI) and its impact on chronic kidney disease (CKD) following pediatric nonkidney solid organ transplantation is unknown. We aimed to determine the incidence of AKI and CKD and examine their relationship among children who received a heart, lung, liver, or multiorgan transplant at the Hospital for Sick Children between 2002 and 2011. AKI was assessed in the first year posttransplant. Among 303 children, perioperative AKI (within the first week) occurred in 67% of children, and AKI after the first week occurred in 36%, with the highest incidence among lung and multiorgan recipients. Twenty-three children (8%) developed CKD after a median follow-up of 3.4 years. Less than 5 children developed end-stage renal disease, all within 65 days posttransplant. Those with 1 AKI episode by 3 months posttransplant had significantly greater risk for developing CKD after adjusting for age, sex, and estimated glomerular filtration rate at transplant (hazard ratio: 2.77, 95% confidence interval, 1.13-6.80, P trend = .008). AKI is common in the first year posttransplant and associated with significantly greater risk of developing CKD. Close monitoring for kidney disease may allow for earlier implementation of kidney-sparing strategies to decrease risk for progression to CKD.

Preoperative right heart hemodynamics predict postoperative acute kidney injury after heart transplantation

Purpose

Acute kidney injury (AKI) frequently occurs after heart transplantation (HTx), but its relation to preoperative right heart hemodynamic (RHH) parameters remains unknown. Therefore, we aimed to determine their predictive properties for postoperative AKI severity within 30 days after HTx.

Methods

From 1984 to 2016, all consecutive HTx recipients (n = 595) in our tertiary referral center were included and analyzed for the occurrence of postoperative AKI staged by the kidney disease improving global outcome criteria. The effects of preoperative RHH parameters on postoperative AKI were calculated using logistic regression, and predictive accuracy was assessed using integrated discrimination improvement (IDI), net reclassification improvement (NRI), and area under the receiver operating characteristic curves (AUC).

Results

Postoperative AKI occurred in 430 (72%) patients including 278 (47%) stage 1, 66 (11%) stage 2, and 86 (14%) stage 3 cases. Renal replacement therapy (RRT) was administered in 41 (7%) patients. Patients with higher AKI stages had also higher baseline right atrial pressure (RAP; median 7, 7, 8, and in RRT 11 mmHg, p trend = 0.021), RAP-to-pulmonary capillary wedge pressure ratio (median 0.37, 0.36, 0.40, 0.47, p trend = 0.009), and lower pulmonary artery pulsatility index (PAPi) values (median 2.83, 3.17, 2.54, 2.31, p trend = 0.012). Higher RAP and lower PAPi values independently predicted AKI severity [adjusted odds ratio (OR) per doubling of RAP 1.16 (1.02–1.32), p = 0.029; of PAPi 0.85 (0.75–0.96), p = 0.008]. Based on IDI, NRI, and delta AUC, inclusion of these parameters improved the models’ predictive accuracy.

Conclusions

Preoperative PAPi and RAP strongly predict the development of AKI early after HTx and can be used as early AKI predictors.

Electronic supplementary material

The online version of this article (10.1007/s00134-018-5159-z) contains supplementary material, which is available to authorized users.