Acute Kidney Injury After Lung Transplantation: Perioperative Risk Factors and Outcome

Impact of recipient and donor pretransplantation body mass index on early postosperative complications after lung transplantation

BACKGROUND

Prior studies have assessed the impact of the pretransplantation recipient body mass index (BMI) on patient outcomes after lung transplantation (LT), but they have not specifically addressed early postoperative complications. Moreover, the impact of donor BMI on these complications has not been evaluated. The first aim of this study was to assess complications during hospitalization in the ICU after LT according to donor and recipient pretransplantation BMI.

METHODS

All the recipients who underwent LT at Bichat Claude Bernard Hospital, Paris, between January 2016 and August 2022 were included in this observational retrospective monocentric study. Postoperative complications were analyzed according to recipient and donor BMIs. Univariate and multivariate analyses were also performed. The 90-day and one-year survival rates were studied. P < 0.05 was considered to indicate statistical significance. The Paris-North Hospitals Institutional Review Board approved the study.

RESULTS

A total of 304 recipients were analyzed. Being underweight was observed in 41 (13%) recipients, a normal weight in 130 (43%) recipients, and being overweight/obese in 133 (44%) recipients. ECMO support during surgery was significantly more common in the overweight/obese group (p = 0.021), as were respiratory complications (primary graft dysfunction (PGD) (p = 0.006), grade 3 PDG (p = 0.018), neuroblocking agent administration (p = 0.008), prone positioning (p = 0.007)), and KDIGO 3 acute kidney injury (p = 0.036). However, pretransplantation overweight/obese status was not an independent risk factor for 90-day mortality. An overweight or obese donor was associated with a decreased PaO2/FiO2 ratio before organ donation (p < 0.001), without affecting morbidity or mortality after LT.

CONCLUSION

Pretransplantation overweight/obesity in recipients is strongly associated with respiratory and renal complications during hospitalization in the ICU after LT.

Interorgan communication networks in the kidney-lung axis

The homeostasis and health of an organism depend on the coordinated interaction of specialized organs, which is regulated by interorgan communication networks of circulating soluble molecules and neuronal connections. Many diseases that seemingly affect one primary organ are really multiorgan diseases, with substantial secondary remote organ complications that underlie a large part of their morbidity and mortality. Acute kidney injury (AKI) frequently occurs in critically ill patients with multiorgan failure and is associated with high mortality, particularly when it occurs together with respiratory failure. Inflammatory lung lesions in patients with kidney failure that could be distinguished from pulmonary oedema due to volume overload were first reported in the 1930s, but have been largely overlooked in clinical settings. A series of studies over the past two decades have elucidated acute and chronic kidney-lung and lung-kidney interorgan communication networks involving various circulating inflammatory cytokines and chemokines, metabolites, uraemic toxins, immune cells and neuro-immune pathways. Further investigations are warranted to understand these clinical entities of high morbidity and mortality, and to develop effective treatments.

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.

Prolonged mechanical ventilation after lung transplantation: risks factors and consequences on recipient outcome

Background

Risk factors and the incidence of prolonged mechanical ventilation (PMV) after lung transplantation (LT) have been poorly described. The study assessed predictive factors of PMV after LT.

Methods

This observational, retrospective, monocentric study included all patients who received LT in Bichat Claude Bernard Hospital between January 2016 and December 2020. PMV was defined as a duration of MV > 14 days. Independent risk factors for PMV were studied using multivariate analysis. One-year survival depending on PMV was studied using Kaplan Meier and log-rank tests. A p value <0.05 was defined as significant.

Results

224 LT recipients were analysed. 64 (28%) of them received PMV for a median duration of 34 [26-52] days versus 2 [1-3] days without PMV. Independent risk factors for PMV were higher body mass index (BMI) (p = 0.031), diabetes mellitus of the recipient (p = 0.039), ECMO support during surgery (p = 0.029) and intraoperative transfusion >5 red blood cell units (p < 0.001). Increased mortality rates were observed at one-year in recipients who received PMV (44% versus 15%, p < 0.001).

Conclusion

PMV was associated with increased morbidity and mortality one-year after LT. Preoperative risk factors (BMI and diabetes mellitus) must be considered when selecting and conditioning the recipients.

Donors brain-dead after successful resuscitation of cardiac arrest: Early outcome and postoperative complications of lung recipients

BACKGROUND

The outcomes of lung transplantation (LT) recipients who received a graft from a brain-dead donor after successful resuscitation from cardiac arrest (CA donors) have been poorly described. This study compared the one-year survival of LT recipients depending on the CA status of the donor.

METHODS

This prospective observational single-centre study analysed all consecutive patients who underwent LT at Bichat Claude Bernard Hospital, Paris, between January 2016 and December 2020. All donors who experienced CA prior to organ donation, regardless of rhythm or duration, were considered CA donors. The postoperative complications and outcomes of LT recipients were analysed. The one-year survival was compared using Kaplan-Meier curves and log-rank tests. Independent risk factors for one-year mortality were assessed using multivariate analysis (p < 0.05 was considered significant). The Paris North Hospitals Institutional Review Board approved the study.

RESULTS

A total of 236 LT recipients were analysed and 66 (28%) received a graft from a CA donor. The median durations of no/low flow were 4 [0-10]/20 [15-30] minutes, respectively. Shockable and non-shockable rhythms were observed in 11 (17%) and 47 (72%) of the CA donors, respectively. The characteristics of the grafts and early postoperative complications were not different in the CA and non-CA groups. Receiving a graft from a CA donor was not an independent risk factor for recipient one-year mortality.

CONCLUSION

Receiving a graft from a CA donor did not worsen the outcome of LT recipients. Acceptation of these grafts must be systematically considered to increase the pool of available grafts.

ECMO support as a bridge to lung transplantation is an independent risk factor for bronchial anastomotic dehiscence

BACKGROUND

Airway complications are frequent after lung transplantation (LT), as they affect up to 23% of recipients. The implication of perioperative extracorporeal membrane oxygenation (ECMO) support and haemodynamic instability has never been specifically assessed. The first aim of this study was to explore the impact of perioperative ECMO support on bronchial anastomotic dehiscence (BAD) at Day 90 after LT.

METHODS

This prospective observational monocentric study analysed BAD in all consecutive patients who underwent LT in the Bichat Claude Bernard Hospital, Paris, France, between January 2016 and May 2019. BAD visible on bronchial endoscopy and/or tomodensitometry was recorded. A univariate analysis was performed (Fisher's exacts and Mann-Whitney tests), followed by a multivariate analysis to assess independent risk factors for BAD during the first 90 days after LT (p < 0.05 as significant). The Paris North Hospitals Institutional Review Board approved the study.

RESULTS

A total of 156 patients were analysed. BAD was observed in the first 90 days in 42 (27%) patients and was the main cause of death in 22 (14%) patients. BAD occurred during the first month after surgery in 34/42 (81%) patients. ECMO support was used as a bridge to LT, during and after surgery in 9 (6%), 117 (75%) and 40 (27%) patients, respectively. On multivariate analysis, ECMO as a bridge to LT (p = 0.04) and septic shock (p = 0.01) were independent risk factors for BAD.

CONCLUSION

ECMO as a bridge to LT is an independent risk factor for BAD during the first 90 days after surgery. Close monitoring of bronchial conditions must be performed in these high-risk recipients.

Cell-Free Hemoglobin in Acute Kidney Injury after Lung Transplantation and Experimental Renal Ischemia/Reperfusion

Cell-free hemoglobin (CFH), a pro-oxidant and cytotoxic compound that is released in hemolysis, has been associated with nephrotoxicity. Lung transplantation (LuTx) is a clinical condition with a high incidence of acute kidney injury (AKI). In this study, we investigated the plasma levels of CFH and haptoglobin, a CFH-binding serum protein, in prospectively enrolled LuTx patients (n = 20) with and without AKI. LuTx patients with postoperative AKI had higher CFH plasma levels at the end of surgery compared with no-AKI patients, and CFH correlated with serum creatinine at 48 h. Moreover, CFH levels inversely correlated with haptoglobin levels, which were significantly reduced at the end of surgery in LuTx patients with AKI. Because multiple other factors can contribute to AKI development in the complex clinical setting of LuTx, we next investigated the role of exogenous CFH administration in a mouse model of mild bilateral renal ischemia reperfusion injury (IRI). Exogenous administration of CFH after reperfusion caused overt AKI with creatinine increase, tubular injury, and enhanced markers of renal inflammation compared with vehicle-treated animals. In conclusion, CFH is a possible factor contributing to postoperative AKI after LuTx and promotes AKI in an experimental model of mild transient renal ischemia. Targeting CFH might be a therapeutic option to prevent AKI after LuTx.

Nonallograft Complications of Lung Transplantation

Long-term exposure to immunosuppressive therapy may exacerbate pre-existing medical comorbidities or result in the development of new chronic medical conditions after lung transplantation. This article focuses on common nonallograft complications with the highest impact on short- and long-term outcomes after transplantation. These include diabetes mellitus, hypertension, dyslipidemia, kidney disease (acute and chronic), and malignancy. We discuss evidence-based strategies for the prevention, diagnosis, and management of these nonallograft complications in this article.

Incidence and Perioperative Risk Factors of Acute Kidney Injury Among Lung Transplant Recipients

BACKGROUND

Acute kidney injury (AKI) is a significant burden in an early postoperative period after lung transplantation (LT). The development of severe AKI, including a need for continuous renal replacement therapy (CRRT), is associated with increased mortality among lung transplant recipients. Evaluation of AKI incidence and predictive factors related to the development of severe AKI and with the use of CRRT in the early postoperative period after LT.

METHODS

Retrospective study of 73 consecutive patients after LT operated between 2015 and 2018 in our center. We noted the stage of AKI according to KDIGO guidelines in the 7 postoperative days.

RESULTS

We noted AKI among 62 lung transplant recipients (84.9%). We recognized the first and second stages of AKI in 21 patients (28.8%) and 19 patients 26%, respectively (group A). We identified severe AKI (group C) in 22 recipients (30.1%), 9 of whom needed CRRT postoperatively. There was a nonsignificant difference between groups in baseline serum creatinine (0.69 ± 0.22 mg/dL vs 0.84 ± 0.34; P = .073). Group C subjects statistically more often suffered from pulmonary hypertension (P < .001) and diabetes (P < .001). In both groups, the duration of the procedure was comparable, but, among patients with severe AKI, procedures were performed more often with the use of extracorporeal circulation (50% vs 68%; P = .194) CONCLUSIONS: Pulmonary hypertension and diabetes could be significant risk factors of high-grade AKI development after LT. Identification of factors modifying renal insufficiency development in lung transplant recipients needs further investigations.

Acute kidney injury following adult lung transplantation

BACKGROUND

Acute kidney injury (AKI) is a common and serious complication following lung transplantation (LTx), and it is associated with high mortality and morbidity. This study assessed the incidence of AKI after LTx and analyzed the associated perioperative factors and clinical outcomes.

METHODS

This retrospective study included all adult LTx recipients at the China-Japan Friendship Hospital in Beijing between March 2017 and December 2019. The outcomes were AKI incidence, risk factors, mortality, and kidney recovery. Multivariate analysis was performed to identify independent risk factors. Survival analysis was presented using the Kaplan-Meier curves.

RESULTS

AKI occurred in 137 of the 191 patients (71.7%), with transient AKI in 43 (22.5%) and persistent AKI in 94 (49.2%). AKI stage 1 occurred in 27/191 (14.1%), stage 2 in 46/191 (24.1%), and stage 3 in 64/191 (33.5%) of the AKI patients. Renal replacement therapy (RRT) was administered to 35/191 (18.3%) of the patients. Male sex, older age, mechanical ventilation (MV), severe hypotension, septic shock, multiple organ dysfunction (MODS), prolonged extracorporeal membrane oxygenation (ECMO), reintubation, and nephrotoxic agents were associated with AKI (P < 0.050). Persistent AKI was independently associated with pre-operative pulmonary hypertension, severe hypotension, post-operative MODS, and nephrotoxic agents. Severe hypotension, septic shock, MODS, reintubation, prolonged MV, and ECMO during or after LTx were related to severe AKI (stage 3) (P < 0.050). Patients with persistent and severe AKI had a significantly longer duration of MV, longer duration in the intensive care unit (ICU), worse downstream kidney function, and reduced survival (P < 0.050).

CONCLUSIONS

AKI is common after LTx, but the pathogenic mechanism of AKI is complicated, and prerenal causes are important. Persistent and severe AKI were associated with poor short- and long-term kidney function and reduced survival in LTx patients.

The Year in Cardiothoracic Transplant Anesthesia: Selected Highlights From 2020 Part I - Lung Transplantation

This special article focuses on the highlights in cardiothoracic transplantation literature in the year 2020. Part I encompasses the recent literature on lung transplantation, including the advances in preoperative assessment and optimization, donor management, including the use of ex-vivo lung perfusion, recipient management, including those who have been infected with coronavirus disease 2019, updates on the perioperative management, including the use of extracorporeal membrane oxygenation, and long-term outcomes.

Incidence and Predictive Factors of Acute Kidney Injury After Off-pump Lung Transplantation

OBJECTIVES

To determine the incidence and predictive factors of acute kidney injury (AKI) after off-pump lung transplantation.

DESIGN

A retrospective cohort study.

SETTING

The operating room and intensive care unit.

PARTICIPANTS

Adult patients who underwent lung transplant without cardiopulmonary bypass or extracorporeal membrane oxygenator between 2006 and 2016 at the Vanderbilt University Medical Center.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The presence of postoperative AKI was assessed by the Kidney Disease: Improving Global Outcomes criteria in the first seven postoperative days. Multivariate logistic regression analysis was used to determine the independent predictive factors of AKI. One hundred forty-eight patients were included in the final analysis, of whom 63 (42.6%) subsequently developed AKI: 43 (29.0%) stage 1, ten (6.8%) stage 2, and ten (6.8%) stage 3. Patients who had AKI had a longer hospital length of stay (12 days [interquartile range (IQR): 10-17] vs ten days [IQR: 8-12], p < 0.001). For every one-year increase in age, the odds of AKI decreased by 8% (odds ratio [OR] 0.92, 95% confidence interval [CI]: 0.87-0.98, p = 0.008). The odds of having AKI in patients with bilateral lung transplant was lower than patients with unilateral transplant (OR 0.09, 95% CI: 0.01-0.63, p = 0.015). Additionally, a diagnosis of chronic obstructive pulmonary disease increased the odds of AKI by four-fold compared with a diagnosis of idiopathic pulmonary fibrosis (OR 4.73, 95% CI: 1.44-15.56, p = 0.011).

CONCLUSIONS

AKI is a common complication after off-pump lung transplantation and is associated with increased hospital length of stay. Younger age, unilateral lung transplant, and diagnosis of chronic obstructive pulmonary disease are independently associated with AKI.

Calcineurin Inhibitor-Based Maintenance Immunosuppression in Lung Transplant Recipients: Optimal Serum Levels for Managing Acute Rejection and Renal Function

BACKGROUND

Although effective for curtailing alloimmune responses, calcineurin inhibitors (CNIs) have an adverse-effect profile that includes nephrotoxicity. In lung transplant (LTx) recipients, the optimal serum levels of the CNI tacrolimus necessary to control alloimmune responses and minimize nephrotoxicity are unknown.

METHODS

This retrospective, single-center study reviewed tacrolimus whole blood trough levels (BTLs), grades of acute cellular rejection (ACR), acute rejection scores, and creatinine clearance (CrCl) obtained in LTx recipients within the first year after their transplant procedure. Comparisons were made between the first 90 days post LTx (when tacrolimus BTLs were maintained >10 µg/L) and the remainder of the post-LTX year (when BTLs were <10 µg/L).

RESULTS

Despite tacrolimus mean BTLs being higher during the first 90 days post LTx compared with the remainder of the first post-LTx year (10.4 ± 0.3 µg/L vs 9.5 ± 0.3 µg/L, P < .0001) there was no association with lower grades of ACR (P = .24). The intensity of ACR (as determined by acute rejection scores) did not correlate with tacrolimus mean BTLs at any time during the first posttransplant year (P = .79). During the first 90 days post LTx there was a significant decline in CrCl and a correlation between increasing tacrolimus mean BTLs and declining CrCl (r = -0.26, P = .03); a correlation that was not observed during the remainder of the year (r = -0.09, P = .52).

CONCLUSIONS

In LTx recipients, maintaining BTLs of the CNI tacrolimus >10µg/L did not result in superior control of acute rejection responses but was associated with declining renal function.

Blood transfusion of the donor is associated with stage 3 primary graft dysfunction after lung transplantation

BACKGROUND

The first aim of this study was to assess the association between stage 3 PGD and pre-donation blood transfusion of the donor. The secondary objectives were to assess the epidemiology of donor transfusion and the outcome of LT recipients according to donor transfusion status and massive donor transfusion status.

METHODS

This was an observational, prospective, single-center study. The results are expressed as absolute numbers, percentages, medians, and interquartile ranges. Statistical analyses were performed using Chi squared, Fischer's exact tests, and Mann-Whitney U tests (P < .05 was considered significant). A multivariate analysis was performed.

RESULTS

Between January 2016 and February 2019, 147 patients were included in the analysis. PGD was observed in 79 (54%) patients, 45 (31%) of whom had stage 3 PGD. Pre-donation blood transfusion was administered in 48 (33%) donors (median of 3[1-9] packed red cells (PRCs)). On multivariate analysis, stage 3 PGD was significantly associated with donor blood transfusion (OR 2.69, IC (1.14-6.38), P = .024). Mortality at days 28 and 90 was not significantly different according to the pre-donation transfusion status of the donor.

CONCLUSION

Pre-donation blood transfusion is associated with stage 3 PGD occurrence after LT. Transfusion data of the donor should be included in donor lung assessment.

Early postoperative complications in lung transplant recipients

Lung transplantation has become an established therapy for end-stage lung diseases. Early postoperative complications can impact immediate, mid-term, and long-term outcomes. Appropriate management, prevention, and early detection of these early postoperative complications can improve the overall transplant course. In this review, we highlight the incidence, detection, and management of these early postoperative complications in lung transplant recipients.

Acute kidney injury after lung transplantation: a narrative review

Acute kidney injury (AKI) is a commonly recognized complication after lung transplantation (LT) and is related to increased mortality and morbidity. With the improvement of survival after LT and the increasing number of lung transplant recipients, the detrimental impact of current management on renal function has become increasingly apparent. Multifarious risk factors in the perioperative setting contribute to the development of AKI, including the preoperative status and complications of the recipient, complex perioperative problems especially hemodynamic fluctuation, and exposure to nephrotoxic agents, mainly calcineurin inhibitors (CNIs) and antimicrobial drugs. Identification and minimization of the effects of these risk factors can relieve AKI severity and incidence in high-risk patients. Close monitoring of urine output and serum creatinine (sCr) levels and of specific biomarkers may promote early recognition of AKI and rapid nephrology intervention to improve outcomes. This review summarizes advances in the epidemiology, diagnostic criteria, biological markers of AKI, and further recommends appropriate treatment strategies for the long-term management of AKI related manifestations in lung transplant recipients. Future work will need to focus on developing more accurate measures of renal function and identifying patients before the occurrence of early renal damage. Combining renal protection strategies with the use of new biomarkers to develop early kidney risk identification and protection protocols is a promising idea that requires further investigation.

Retrospective analysis on incidence and risk factors of early onset acute kidney injury after lung transplantation and its association with mortality

OBJECTIVES

Acute kidney injury (AKI) is a common complication after lung transplantation (LTx) which is closely related to the poor prognosis of patients. We aimed to explore potential risk factors and outcomes associated with early post-operative AKI after LTx.

METHODS

A retrospective study was conducted in 136 patients who underwent LTx at our institution from 2017 to 2019. AKI was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) guideline. Univariate and multivariate analyses were conducted to identify risk factors related to AKI. The primary outcome was the incidence of AKI after LTx. Secondary outcomes were associations between AKI and short-term clinical outcomes and mortality.

RESULTS

Of the 136 patients analyzed, 110 developed AKI (80.9%). AKI was associated with higher baseline eGFR (odds ratio (OR) 1.01 (95% confidence interval (CI): 1.00-1.03)) and median tacrolimus (TAC) concentration (OR 1.15 (95% CI: 1.02-1.30)). Patients with AKI suffered longer mechanical ventilation days (p = .015) and ICU stay days (p = .011). AKI stage 2-3 patients had higher risk of 1-year mortality (HR 16.98 (95% CI: 2.25-128.45)) compared with no-AKI and stage 1 patients.

CONCLUSIONS

Our results suggested early post-operative AKI may be associated with higher baseline eGFR and TAC concentrations. AKI stage 1 may have no influence on survival rate, whereas AKI stage 2-3 may be associated with increased mortality at 1-year.