Acute kidney injury after Fontan completion: Risk factors and outcomes

Urinary biomarkers improve prediction of AKI in pediatric cardiac surgery

Acute kidney injury (AKI) is a common postoperative complication of paediatric congenital heart disease (CHD) surgery, associated with increased morbidity and mortality. Current diagnostic approaches are unreliable in the early postoperative period, delaying diagnosis and treatment. This study investigates the efficacy of inflammatory and renal biomarkers in the early detection of postoperative AKI in paediatric CHD surgery patients. Biomarkers were assessed in urine and serum samples collected pre- and 24 h postoperatively from paediatric patients (median age 27 weeks) undergoing corrective CHD surgery (n = 76). Univariate and subsequent multivariate regression analysis with least absolute shrinkage and selected operator (LASSO) regularisation was performed to identify key predictors stratified by AKI diagnosis at 48 h. Significant biomarkers were included in a compound regression model which was evaluated through receiver operator curve analysis. Internal validation of the models was carried out through bootstrapping. Postoperative urine concentrations of interleukin-18 were significantly higher in those with postoperative AKI (p = 0.015), whereas uromodulin concentrations were lower (p = 0.010). Uromodulin, interleukin-18, and serum Fatty Acid Binding Protein 3 were associated with AKI (p = 0.011, 0.040, 0.042 respectively), with uromodulin and interleukin-18 performing strongly in a compound model withstanding LASSO regularisation, demonstrating an area under the curve of 0.899, sensitivity of 0.741, and specificity of 0.913. Urine uromodulin and interleukin-18 can be used to accurately predict postoperative AKI when measured at 24 h after surgery. Prompt recognition of postoperative AKI would facilitate early intervention, potentially mitigating the most severe consequences of renal injury.

The Association Between Platelet Transfusion and Acute Kidney Injury Following Fontan Surgery

Objectives: Previous studies have demonstrated an association between transfusion and increased organ dysfunction. We sought to determine the association between transfusion of blood components (red blood cell [RBC], plasma, platelet, and cryoprecipitate transfusions) with development of acute kidney injury (AKI) in children following the Fontan procedure. Methods: This is a single center, retrospective cohort study from 2009 to 2016. All children who underwent the Fontan procedure during the prescribed period who had transfusion and laboratory data available were included. Results: Eighty-eight children were enrolled. The median (interquartile range [IQR]) age was 4.5 (3.3-6.0) years, and median (IQR) weight was 14.8 (13.0-18.8) kg. The median (IQR) cardiopulmonary bypass (CPB) time was 62 (47-89) minutes. Following surgery, according to Kidney Disease Improving Global Outcomes criteria, 41% (36/88) had stage 1 AKI, 23% (20/88) stage 2 AKI, and 15% (13/88) stage 3 AKI. Fifty-eight percent (51/88) of children received at least one RBC transfusion, 73% (64/88) received at least one plasma transfusion, 47% (41/88) received at least one platelet transfusion, and 28% (25/88) received at least one cryoprecipitate transfusion. Children with severe AKI received more of each blood component. After adjusting for age, weight, pre-Fontan pulmonary vascular resistance, pre-Fontan dominant ventricular end-diastolic pressure, CPB time, RBC dose, plasma dose, and cryoprecipitate dose, each 1 mL/kg of platelet transfusion was associated with an increased risk in development of severe AKI (odds ratio: 1.160, 95%CI 1.006-1.339, P = .041). Conclusions: In our cohort of children undergoing the Fontan procedure, platelet transfusion was independently associated with an increased risk of severe AKI postoperatively. The risks, benefits, and alternatives to transfusion should be carefully weighed in this patient population.

Acute Kidney Injury and Mid-term Outcomes After Extra-Cardiac Fontan Conversion

The aim of this study was to investigate the association of postoperative acute kidney injury and unplanned re-admission rate due to heart failure at 2 years follow-up in patients who had extra-cardiac Fontan conversion. This was a retrospective single-center study of patients who underwent conversion from classic Fontan to extra-cardiac Fontan between January 2014 and December 2021. Acute kidney injury was defined using the Kidney Disease Improving Global Outcomes criteria. A total of 47 patients underwent Fontan conversion. Acute kidney injury occurred in 22 patients (46.8%) and 5 patients with acute kidney injury needed renal replacement therapy. Unplanned re-admission rate at 2-year follow-up was significantly higher in patients with acute kidney injury even when renal function returned to baseline (8 [36.4%] vs. 3 [12.0%], p = 0.026 by the log-rank test). In conclusion, postoperative acute kidney injury after extra-cardiac Fontan conversion was associated with unplanned re-admission due to heart failure at 2-year follow-up even though renal function was recovered.

Engineered human iPS cell models reveal altered podocytogenesis and glomerular capillary wall in CHD-associated SMAD2 mutations

Early developmental programming involves extensive cell lineage diversification through shared molecular signaling networks. Clinical observations of congenital heart disease (CHD) patients carrying SMAD2 genetic variants revealed correlations with multi-organ impairments at the developmental and functional levels. For example, many CHD patients present with glomerulosclerosis, periglomerular fibrosis, and albuminuria. Still, it remains largely unknown whether SMAD2 variants associated with CHD can directly alter kidney cell fate, tissue patterning, and organ-level function. To address this question, we engineered human iPS cells (iPSCs) and organ-on-a-chip systems to uncover the role of pathogenic SMAD2 variants in kidney podocytogenesis. Our results show that abrogation of SMAD2 causes altered patterning of the mesoderm and intermediate mesoderm (IM) cell lineages, which give rise to nearly all kidney cell types. Upon further differentiation of IM cells, the mutant podocytes failed to develop arborizations and interdigitations. A reconstituted glomerulus-on-a-chip platform exhibited significant proteinuria as clinically observed in glomerulopathies. This study implicates CHD-associated SMAD2 mutations in kidney tissue malformation and provides opportunities for therapeutic discovery in the future.

Persistent acute kidney injury and fluid accumulation with outcomes after the Norwood procedure: report from NEPHRON

BACKGROUND

Cardiac surgery-associated acute kidney injury (CS-AKI) is common, but its impact on clinical outcomes is variable. Parsing AKI into sub-phenotype(s) and integrating pathologic positive cumulative fluid balance (CFB) may better inform prognosis. We sought to determine whether durational sub-phenotyping of CS-AKI with CFB strengthens association with outcomes among neonates undergoing the Norwood procedure.

METHODS

Multicenter, retrospective cohort study from the Neonatal and Pediatric Heart and Renal Outcomes Network. Transient CS-AKI: present only on post-operative day (POD) 1 and/or 2; persistent CS-AKI: continued after POD 2. CFB was evaluated per day and peak CFB during the first 7 postoperative days. Primary and secondary outcomes were mortality, respiratory support-free and hospital-free days (at 28, 60 days, respectively). The primary predictor was persistent CS-AKI, defined by modified neonatal Kidney Disease: Improving Global Outcomes criteria.

RESULTS

CS-AKI occurred in 59% (205/347) neonates: 36.6% (127/347) transient and 22.5% (78/347) persistent; CFB > 10% occurred in 18.7% (65/347). Patients with either persistent CS-AKI or peak CFB > 10% had higher mortality. Combined persistent CS-AKI with peak CFB > 10% (n = 21) associated with increased mortality (aOR: 7.8, 95% CI: 1.4, 45.5; p = 0.02), decreased respiratory support-free (predicted mean 12 vs. 19; p < 0.001) and hospital-free days (17 vs. 29; p = 0.048) compared to those with neither.

CONCLUSIONS

The combination of persistent CS-AKI and peak CFB > 10% after the Norwood procedure is associated with mortality and hospital resource utilization. Prospective studies targeting intra- and postoperative CS-AKI risk factors and reducing CFB have the potential to improve outcomes.

Acute kidney injury and renal recovery following Fontan surgery

Objectives

Acute kidney injury has been described after Fontan surgery, but the duration and outcomes are unknown. We sought to describe the incidence of and risk factors for acute kidney injury and the phenotype of renal recovery, and evaluate the impact of renal recovery phenotype on outcomes.

Methods

All children who underwent a Fontan operation at a single center between 2009 and 2022 were included. Data collected included Fontan characteristics, vasopressor use, all measures of creatinine, and postoperative outcomes. Logistic regression models were used to assess predictors of acute kidney injury and the association between acute kidney injury and outcomes.

Results

We enrolled 141 children (45% female). Acute kidney injury occurred in 100 patients (71%). Acute kidney injury duration was transient (<48 hours) in 77 patients (55%), persistent (2-7 days) in 15 patients (11%), more than 7 days in 4 patients (3%), and unknown in 4 patients (3%). Risk factors for acute kidney injury included higher preoperative indexed pulmonary vascular resistance (odds ratio, 3.90; P = .004) and higher postoperative inotrope score on day 0 (odds ratio, 1.13, P = .047). Risk factors for acute kidney injury duration more than 48 hours included absence of a fenestration (odds ratio, 3.43, P = .03) and longer duration of cardiopulmonary bypass (odds ratio, 1.22 per 15-minute interval, P = .01). Acute kidney injury duration more than 48 hours was associated with longer length of stay compared with transient acute kidney injury (median 18 days [interquartile range, 9-62] vs 10 days [interquartile range, 8-16], P = .006) and more sternal wound infections (17% vs 4%, P = .049).

Conclusions

Acute kidney injury after the Fontan operation is common. The occurrence and duration of acute kidney injury have significant implications for postoperative outcomes.

Long-term outcomes of acute kidney injury in children

PURPOSE OF REVIEW

Acute kidney injury (AKI) affects up to 35% of all critically ill children and is associated with substantial short-term morbidity and mortality. However, the link between paediatric AKI and long-term adverse outcomes remains incompletely understood. This review highlights the most recent clinical data supporting the role of paediatric AKI as a risk factor for long-term kidney and cardiovascular consequences. In addition, it stresses the need for long-term surveillance of paediatric AKI survivors.

RECENT FINDINGS

Recent large-scale studies have led to an increasing understanding that paediatric AKI is a significant risk factor for adverse outcomes such as hypertension, cardiovascular disease and chronic kidney disease (CKD) over time. These long-term sequelae of paediatric AKI are most often observed in vulnerable populations, such as critically ill children, paediatric cardiac surgery patients, children who suffer from severe infections and paediatric cancer patients.

SUMMARY

A growing body of research has shown that paediatric AKI is associated with long-term adverse outcomes such as CKD, hypertension and cardiovascular disease. Although therapeutic pathways tailored to individual paediatric AKI patients are yet to be validated, we provide a framework to guide monitoring and prevention in children at the highest risk for developing long-term kidney dysfunction.

Long-Term Consequences of Acute Kidney Injury After Pediatric Cardiac Surgery: A Systematic Review

OBJECTIVE

The objective of this study was to evaluate the available data on long-term kidney dysfunction, hypertension, and mortality after cardiac surgery-associated acute kidney injury (AKI) in the pediatric population.

STUDY DESIGN

PubMed/MEDLINE, Embase, Scopus, and reference lists of relevant articles were searched for eligible studies published from inception through March 2022. Long-term outcomes after pediatric cardiac surgery complicated by AKI and those without were investigated.

RESULTS

We identified 14 studies published between 2013 and 2022 that included a total of 6701 patients (AKI: 1376 patients; no AKI: 5325 patients). These studies used different well-established classifications to define AKI. All the studies suggested that AKI after heart surgery is common in the pediatric patient population and reported a potential link between cardiac surgery-associated AKI and important clinical outcomes. However, only 4 out of 11 studies found a strong association between (absence of recovery from) cardiac surgery-associated AKI and risk of developing chronic kidney disease, and 3 out of 5 studies found a significant increase in mortality rates for pediatric patients who developed AKI after cardiac surgery. Only 1 out of 4 studies found an association between AKI and hypertension at 12 months postoperatively, but found no association at later follow-up times.

CONCLUSIONS

Although there is a trend, evidence on the long-term consequences of cardiac surgery-associated AKI in the pediatric population is mixed. Genetic syndromes, preexisting kidney disease, univentricular or cyanotic heart conditions, and/or high-complexity surgery may be more important for the development of kidney dysfunction by adolescence and early adulthood. Regardless, these children may benefit from a long-term kidney follow-up.

National outcomes of the Fontan operation with endocardial cushion defect

BACKGROUND

The traditional outcomes of the Fontan operation (FO) in endocardial cushion defect (ECD) patients have been suboptimal. Previous studies have been limited by the smaller number of ECD patients, longer study period with an era effect, and do not directly compare short-term outcomes of FO in ECD patients with non-ECD patients. Our study aims to address these shortcomings.

METHODS

A retrospective analysis of the Kids Inpatient Database (2009, 2012, and 2016) for the FO was done. The groups were divided into those who underwent FO with ECD as compared to non-ECD diagnosis. The data were abstracted for demographics, clinical characteristics, and operative outcomes. Standard statistical tests were used.

RESULTS

Three thousand three hundred eighty patients underwent the FO of which 360 patients (11%) were FO-ECD. ECD patients were more likely to have Down syndrome, Heterotaxy syndrome, transposition/DORV, and TAPVR as compared to non-ECD patients. FO-ECD had a higher discharge-mortality (2.84% vs. 0.45%, p = .04). The length of stay (16 vs. 13 days, p = .05) and total charges incurred ($283, 280 vs. $234, 106, p = .03) for the admission were higher in the FO-ECD as compared to non-ECD patients. In multivariable analysis, ECD diagnosis, cardiac arrest, acute kidney injury, and postoperative hemorrhage were predictors of mortality.

CONCLUSION

Contemporary outcomes for FO are excellent with very low overall operative mortality. However, the outcomes in ECD patients are inferior with higher operative mortality than in non-ECD patients. The occurrence of postoperation complications and a diagnosis of ECD were predictive of a negative outcome.

Post-operative Morbidity and Mortality After Fontan Procedure in Patients with Heterotaxy and Other Situs Anomalies

Heterotaxy is a complex, multisystem disorder associated with single ventricle heart disease and decreased survival. Ciliary dysfunction is common in heterotaxy and other situs abnormalities (H/SA) and may increase post-operative complications. We hypothesized that patients with H/SA have increased respiratory and renal morbidities and increased in-hospital mortality after Fontan procedure. We queried the Pediatric Health Information System database for hospitalizations with ICD-9/10 codes for Fontan procedure in patients aged 1 through 11 years from 2004 to 2019. H/SA was identified by codes for dextrocardia, situs inversus, asplenia/polysplenia, or atrial isomerism and compared to non-H/SA controls. Outcomes were in-hospital mortality or heart transplantation, ECMO, hemodialysis, length of stay (LOS), and mechanical ventilation or vasoactive medication use ≥ 4 days. We adjusted estimates with multivariable logistic regression. Of 7897 patients at 50 centers, 1366 (17%) met criteria for H/SA. H/SA had worse outcomes for all study measures: death/transplantation (1.9 vs 1.1%, OR 1.74 (95% CI 1.01-3.03); p = 0.047), ECMO (3.7 vs 2.3%, OR 1.74 (1.28-2.35); p < 0.001), hemodialysis (2.1 vs 1.2%, OR 1.66 (1.06-2.59); p = 0.026), prolonged mechanical ventilation (13.2% vs 7.6%, OR 1.85 (1.53-2.25); p < 0.001) and vasoactive medication use (29.4 vs 19.7%, OR 1.65 (1.43-1.90), and longer LOS (11 (8-17) vs 9 (7-14) days; p < 0.001). H/SA is associated with increased cardiovascular, renal, and respiratory morbidity, as well as in-hospital mortality after Fontan procedure. Attention to renal and respiratory needs may improve outcomes in this difficult population. The relationship between ciliary dysfunction and lung and renal morbidity should be explored further.

Risk factors and outcomes associated with acute kidney injury following extracardiac total cavopulmonary connection: a retrospective observational study

BACKGROUND

Total cavopulmonary connection (TCPC) is an important operation for the treatment of complex congenital heart disease. Epidemiology and outcomes for pediatric patients with acute kidney injury (AKI) following extracardiac TCPC have not been well documented. This study investigates the prevalence, risk factors, and outcomes of AKI in children after extracardiac TCPC surgery.

METHODS

We retrospectively evaluated patients (age at surgery <18 years) who underwent extracardiac TCPC surgery between January 2008 and January 2020 in the Pediatric Cardiac Surgical Center of Fuwai Hospital, Beijing, China. AKI was defined according to the pediatric-modified risk, injury, failure, loss of function, and end-stage renal disease criteria.

RESULTS

A total of 377 pediatric patients were included in this study; 123 patients (32.6%) had some degree of AKI. Among the patients with AKI, 101 (82.1%) were diagnosed with AKI-risk (AKI-R), while 22 (17.9%) were diagnosed with acute kidney injury/failure (AKI/F) (16 with AKI, and 6 with AKF). Preoperative estimated creatinine clearance (OR: 1.039, 95% CI: 1.024-1.055, P<0.001), neutrophil-to-lymphocyte ratio (OR: 1.208, 95% CI: 1.128-1.294, P<0.001), and renal perfusion pressure (OR: 0.962, 95% CI: 0.938-0.986, P=0.002) on postoperative day (POD) 0 were significantly associated with AKI after TCPC. Having previously undergone a bidirectional Glenn was significantly associated with the severity of postoperative AKI (OR: 0.253, 95% CI: 0.088-0.731, P=0.011). Furthermore, AKI was associated with prolonged mechanical ventilation time, prolonged intensive care unit stay, and composite adverse outcome. Compared with non-AKI patients, the 10-year survival rate of patients with severe AKI was significantly lower (95.5% vs. 65.9%, P=0.009).

CONCLUSIONS

Although the incidence of AKI was high in patients undergoing TCPC surgery, most cases were AKI-R. Severe AKI was significantly associated with early adverse outcomes and poor long-term survival.

Evaluation of postoperative renal functions and its effect on body perfusion in patients with double aortic cannulation

BACKGROUND

The optimal visceral preservation method during aortic arch reconstruction is still controversial. It has been thought that double aortic cannulation is effective. Herein, it was aimed to evaluate this technique in providing distal perfusion.

METHODS

A total of 74 patients who underwent arch reconstruction between 2011 and 2019 were included. Patients were grouped according to ventricular physiology and cannulation strategies. Group 1 were univentricle patients, and all had double aortic cannulation. Group 2 were biventricular patients. Group 2A double aortic cannulation-done and Group 2B non-double aortic cannulation were included. Lactate, urea, creatinine values, renal functions, and need for peritoneal dialysis of patients were evaluated.

RESULTS

There were no complications observed due to descending aortic cannulation in any of the patients. A delayed sternal closure and the need for peritoneal dialysis were more common in the Group 1 (p < 0.01). The preoperative and postoperative 1st- and 2nd-day lactate, urea, and creatinine values in the Group 1 were higher (p < 0.05) when compared with the Group 2A and 2B. The same values were higher in Group 2A than the Group 2B (p < 0.05).

CONCLUSION

The positive effect of double aortic cannulation on renal dysfunction could not be demonstrated. This may be associated with a <1 month of age, low weight, complex surgical procedure, and high preoperative lactate, urea, and creatinine values in patients with double aortic cannulation.

Persistent Markers of Kidney Injury in Children Who Developed Acute Kidney Injury After Pediatric Cardiac Surgery: A Prospective Cohort Study

Background

Acute kidney injury (AKI) after pediatric cardiac surgery is common. Longer‐term outcomes and the incidence of chronic kidney disease after AKI are not well‐known.

Methods and Results

All eligible children (aged <16 years) who had developed AKI following cardiac surgery at our tertiary referral hospital were prospectively invited for a formal kidney assessment ≈5 years after AKI, including measurements of estimated glomerular filtration rate, proteinuria, α₁‐microglobulin, blood pressure, and kidney ultrasound. Longer‐term follow‐up data on kidney function were collected at the latest available visit. Among 571 patients who underwent surgery, AKI occurred in 113 (19.7%) over a 4‐year period. Fifteen of these (13.3%) died at a median of 31 days (interquartile range [IQR], 9–57) after surgery. A total of 66 patients participated in the kidney assessment at a median of 4.8 years (IQR, 3.9–5.7) after the index AKI episode. Thirty‐nine patients (59.1%) had at least 1 marker of kidney injury, including estimated glomerular filtration rate <90 mL/min per 1.73 m² in 9 (13.6%), proteinuria in 27 (40.9%), α₁‐microglobinuria in 5 (7.6%), hypertension in 13 (19.7%), and abnormalities on kidney ultrasound in 9 (13.6%). Stages 1 to 5 chronic kidney disease were present in 18 (27.3%) patients. Patients with CKD were more likely to have an associated syndrome (55.6% versus 20.8%, P=0.015). At 13.1 years (IQR, 11.2–14.0) follow‐up, estimated glomerular filtration rate <90 mL/min per 1.73 m² was present in 18 of 49 patients (36.7%), suggesting an average estimated glomerular filtration rate decline rate of −1.81 mL/min per 1.73 m² per year.

Conclusions

Children who developed AKI after pediatric cardiac surgery showed persistent markers of kidney injury. As chronic kidney disease is a risk factor for cardiovascular comorbidity, long‐term kidney follow‐up in this population is warranted.

Case report and review of the literature: Successful transition from acute continuous veno-venous hemodiafiltration therapy to chronic peritoneal dialysis in a chronically ventilated child with hypoplastic left heart syndrome following fontan

Fontan palliation depends on low pulmonary vascular resistance in order to maintain pulmonary blood flow and adequate oxygenation. This physiology results in higher central venous pressures with limited renal perfusion pressure and cardiac output. Positive pressure ventilation with mechanical ventilation increases intrathoracic pressure and raises central venous pressure and can further limit pulmonary and renal perfusion. Fluid removal with intermittent hemodialysis can be challenging in Fontan patients and can cause intolerable hypotension, however the increased abdominal filling pressures during peritoneal dialysis dwells can exacerbate systemic venous hypertension seen in Fontan patients and threaten adequate pulmonary blood flow and cardiac output. Successful transition to peritoneal dialysis in a chronically ventilated patient with hypoplastic left heart syndrome, end-stage renal disease and Fontan physiology has not been described. We present details outlining the successful transition across multiple modalities of renal replacement therapy to assist other teams faced with similar challenges in chronically ventilated Fontan patients with end-stage renal disease.

Acute Kidney Injury and Renal Replacement Therapy After Fontan Operation

Fontan circulation leads to chronic elevation of central venous pressure. We sought to identify the incidence, risk factors, and survival among patients who developed acute kidney injury (AKI) after the Fontan operation. We retrospectively reviewed 1,166 patients who had Fontan operation/revision at Mayo Clinic Rochester from 1973 to 2017 and identified patients who had AKI (defined by AKI Network criteria) within 7 days of surgery. A total of 132 patients (11%) developed AKI after the Fontan operation with no significant era effect. Of those who developed AKI, severe (grade 3) kidney injury was present in 101 patients (76.5%). Multivariable risk factors for AKI were asplenia (odds ratio [OR] 4.2, p <0.0001), elevated preoperative pulmonary artery pressure (per 1 mm Hg increase, OR 1.04, p = 0.0002), intraoperative arrhythmias (OR 1.9, p = 0.02), and elevated post-bypass Fontan pressure (per 1 mm Hg increase, OR 1.12, p = 0.0007). Renal replacement therapy (RRT) was used in 72 patients (54%), predominantly through peritoneal dialysis (n = 56, 78%). Multivariable risk factors for RRT were age ≤3 years (OR 9.7, p = 0.0004), female gender (OR 2.6, p = 0.02), and aortic cross-clamp time >60 minutes (OR 3.1, p = 0.01). Patients with AKI had more postoperative complications, including bleeding, stroke, pericardial tamponade, low cardiac output state and cardiac arrest, than those without AKI. This resulted in longer intensive care unit stay (39 vs 17 days, p = 0.0001). In-hospital mortality was exceedingly higher among patients with AKI versus no AKI (58%, 76 of 132 vs 10%, 99 of 1,034, p <0.0001); however, there was no significant difference based on the need for RRT. Recovery from AKI was observed in 56 patients (42%). Over 20-year follow-up, patients with AKI had a distinctly higher all-cause-mortality (82%) than those without AKI (35%). It is prudent to identity patients at a higher risk of developing postoperative AKI after Fontan operation to ensure renal protective strategies in the perioperative period. Postoperative AKI leads to substantial short and long-term morbidity and mortality, but the need for RRT does not affect the outcomes.

Contrast media exposure in the perioperative period confers no additional risk of acute kidney injury in infants and young children undergoing cardiac surgery with cardiopulmonary bypass

BACKGROUND

Recently, there has been an interest in the temporal relationship between contrast exposure (CM) and cardiac surgery suggesting that a "double hit" on the kidney function in close succession increases the risk of acute kidney injury (AKI) after cardiac surgery. However, data from young children is limited. The purpose of this study was to retrospectively evaluate the effects of preoperative CM exposure on postoperative AKI in infant and young children patients and to further analyze the influence of exposure time interval.

METHODS

Patients (age ≤ 3 years) who underwent diagnostic imaging within 14 days before on-pump cardiac surgery between 1 May 2017 and 31 May 2018 in Fuwai Hospital, Beijing, were analyzed. Kidney outcome was assessed according to Kidney Disease: Improving Global Outcomes creatinine-based criteria.

RESULTS

One thousand four hundred pediatric patients (192 CM and 1,248 non-CM) were identified. Postoperative AKI occurred in 57 (29.7%) of the 192 patients who were exposed to CM. Following propensity score adjustment, no difference in risk for AKI was observed between the CM and non-CM groups (RR 1.142, 95% CI 0.916-1.424; P = 0.264). Multivariable logistic regression of the CM group indicated that independent predictors of postoperative AKI were lower weight, lower preoperative creatinine level, and longer CPB duration. Time interval between CM exposure and on-pump cardiac surgery was not significantly associated with increased risk of AKI (OR 0.853, 95% CI 0.265~2.747; P = 0.790).

CONCLUSIONS

For pediatric patients who are soon to undergo on-pump cardiac procedures, there appears to be no need to hesitate in performing the diagnostic imaging investigations requiring CM, or delay CPB after CM exposure. These patients may benefit from increased diagnostic utility without increasing their risk of postoperative AKI.

Perioperative and long-term management of Fontan patients

A Fontan circulation requires a series of three-staged operations aimed to palliate patients with single-ventricle CHD. Currently, the most frequent technique is the extracardiac total cavopulmonary connection, an external conduit connecting the IVC and right pulmonary artery, bypassing the right side of the heart. Fontan candidates must meet strict criteria; they are assessed utilising both cardiac catheterisation and cardiac magnetic resonance. Postoperatively, treatment protocols prioritise antibiotic prophylaxis, diuretics, angiotensin-converting enzyme inhibitors, anticoagulation, and oxygen therapy with fluid restriction and a low-fat diet. These measures aim to reduce length of stay in the ICU and hospital by preventing acute complications such as infection, venous thromboembolism, low cardiac output, pleural effusion, and acute kidney injury. Late complications of a Fontan procedure include circulation failure, protein-losing enteropathy, plastic bronchitis, and Fontan-associated liver disease. The definitive management is cardiac transplantation, with promising innovations in selective embolisation of lymphatic vessels and Fontan-specific ventricular assist devices. Further research assessing current protocols in the perioperative management of Fontan patients would be beneficial for standardising current practice and improving outcomes.

Incidence, Predictors, and Impact of Postoperative Acute Kidney Injury Following Fontan Conversion Surgery in Young Adult Fontan Survivors

Acute kidney injury (AKI) is a common complication following single ventricle congenital heart surgery. Data regarding AKI following Fontan conversion (FC) surgery are limited. This study evaluated the incidence, predictors of, and prognostic value of AKI following FC. Single-center retrospective cohort study, including consecutive FC patients from December 1994 to December 2016. Medical records were reviewed. AKI was classified into AKI-1/AKI-2/AKI-3 using Kidney Disease: Improving Global Outcomes criteria. Multivariable logistic regression identified risk factors for AKI≥2. Chi-square and 2-sample t-tests assessed associations between AKI≥2 and postoperative outcomes. Mid-term heart-transplant-free survival among AKI0-1 vs AKI2-3 groups was compared using Kaplan-Meier curves and log-rank test. We included 139 FC patients: age at FC 24 (25th-75th, 19-31) years; 81% initial atrio-pulmonary Fontan; follow-up 8.3 ± 5.3 years following FC. Post-FC, 63 patients (45%) developed AKI (AKI-1 = 37 [27%]; AKI-2 = 10 [7%]; AKI-3 = 16 [11%]). AKI recovered by hospital discharge in 86%, 80%, and 19% of patients with AKI-1/AKI-2/AKI-3, respectively. Independent risk factors for AKI≥2 included older age (OR 1.07, 95%CI 1.01-1.15; P = 0.027); ≥3 prior sternotomies (OR = 6.11; 95%CI = 1.59-23.47; P = 0.009); greater preoperative right atrial pressure (OR 1.19; 1.02-1.38; P = 0.024), and prior catheter ablation procedure (OR 3.45; 1.17-10.18; P = 0.036). AKI≥2 was associated with: longer chest tube duration (9 [5-57] vs 7 [3-28] days; P = 0.01); longer mechanical ventilation time (2 [1-117] vs 1 [1-6] days; P = 0.01); greater need for dialysis (31% v s0%; P < 0.001); and longer postoperative length of stay (18 [8-135] vs 10 [6-58] days; P < 0.001). AKI 2-3 patients had worse mid-term heart-transplant-free survival. Half of the patients undergoing FC develop AKI. AKI 2-3 is associated with worse early postoperative outcomes and reduced mid-term transplant-free survival following FC. Knowledge of AKI predictors may allow for improved FC risk stratification, patient selection, and perioperative management in this high-risk population.

The Incidence and Risk Factors for Persistent Acute Kidney Injury Following Total Cavopulmonary Connection Surgery: A Single-Center Retrospective Analysis of 465 Children

Background: Acute kidney injury (AKI) after cardiac surgery contributes to adverse outcomes. We aimed to assess the incidence and identify the predictors for persistent AKI after total cavopulmonary connection (TCPC) surgery. Methods: A retrospective study, including 465 children undergoing TCPC surgery from 2010 to 2019, was conducted. We used pRIFLE criteria to define AKI and defined persistent AKI as AKIs occurring between post-operative day1 (POD1) and POD3 and sustaining at least on POD7. Univariate and multivariate logistic regressions were applied to analyze the predictors for persistent AKI. Results: A total of 35.3% patients developed AKI between POD1 to POD3 and 15.5% patents had persistent AKI after TCPC. Patients with persistent AKI had prolonged mechanical ventilation and ICU stay, and had higher rates of renal replacement treatment and reintubation, which was associated with higher hospitalization costs and in-hospital mortality. The independent predictors for persistent AKI were peripheral oxygen saturation (SpO2) upon admission, intraoperative fluid balance, POD0 maximal lactic acid, renal perfusion pressure (RPP), POD0 estimated glomerular filtration rate and POD0 total bilirubin. The areas under receiver operating characteristic curve (AUC) in the total cohort and the subgroup undergoing TCPC surgery after 2017 were 0.75 (95% CI, 0.66-0.82) and 0.87 (95% CI, 0.77-0.97), respectively. The acceptable AUCs (nearly 0.7) were achieved in other 5 subgroups and good calibration ability (p ≥ 0.05) were achieved in the total cohort and all six subgroups. Conclusions: Persistent AKI after TCPC was common and strongly associated with poorer in-hospital outcomes in Chinese pediatric patients. Six perioperative variables, including SpO2, intraoperative fluid balance, POD0 maximal lactic acid, RPP, POD0 moderate-to-severe kidney injury and POD0 total bilirubin, were identified as independent predictors for persistent AKI. Our findings may help to perform an early risk stratification for these vulnerable patients and improve their outcomes.

Acute and Chronic Kidney Disease Following Congenital Heart Surgery: A Review

BACKGROUND

There is an increasing prevalence of chronic kidney disease in the population of adults currently living with congenital heart disease. A considerable proportion of children who undergo congenital heart surgery experience postoperative acute kidney injury. Whether there is an association between acute kidney injury after cardiac surgery in childhood and development of chronic kidney disease is unclear.

METHODS

Three electronic databases were searched to capture relevant studies exploring the relationship between acute kidney injury after congenital heart surgery in children and progression to chronic kidney disease.

RESULTS

A literature search identified a total of 212 research articles, 7 of which were selected for in-depth review.

CONCLUSIONS

There is a likely association between acute kidney injury in children undergoing congenital heart surgery and progression to chronic kidney disease. Research should be developed to mitigate factors contributing to postoperative acute kidney injury in neonates, infants, and children undergoing cardiac surgery. Better targeted follow-up protocols to monitor renal function in children undergoing cardiac surgery should be implemented. A universal definition for acute kidney injury and chronic kidney disease is needed to improve detection and research in this field.

Perioperative Considerations for the Fontan Patient Requiring Noncardiac Surgery

Children and adults with congenital heart disease undergoing noncardiac surgery are at higher risk of perioperative adverse events. Patients have significant comorbidities and syndromic associations that increase perioperative risk further. The complexity of congenital heart disease requires a thorough understanding of lesion-specific pathophysiology in order to provide safe care. Comprehensive multidisciplinary planning and the use of skilled and experienced teams achieve the best outcomes. The anesthesiologist is a perioperative physician charged with providing safe anesthesia care, instituting appropriate hemodynamic monitoring, and determining appropriate postoperative disposition on an individual basis.

Chronic Kidney Disease in Adolescents after Surgery for Congenital Heart Disease

BACKGROUND

The onset of chronic kidney disease (CKD) is an important prognostic factor in young adults with congenital heart disease (CHD). Although it is likely that CKD is manifest early in CHD patients, the prevalence among adolescents is still unknown. The National Kidney Foundation's Kidney Disease Improving Global Outcomes guidelines 2012 recommend new equations for the estimated glomerular filtration rate (eGFR) and highlight the importance of albuminuria for CKD screening. The objective of the present study was to estimate the prevalence of CKD in CHD adolescents.

METHODS

This observational cross-sectional study included 115 patients aged 10-18 years attending the cardiologic outpatient clinic at our institution as a follow-up after cardiac surgery in infancy related to various CHDs. CKD assessment used the CKD criteria 2012, including eGFR equations based on serum creatinine and cystatin C, and measurement of albuminuria.

RESULTS

No patient had an eGFR <60 mL min-1 1.73 m-2. However, 28.7% of all patients (95% CI 20.7-37.9) had eGFRbetween 60 and 89 mL min-1 1.73 m-2 when estimated by the bedside Schwartz creatinine-based equation,and 17.4% (95% CI 11.2-24.1) had eGFRbetween 60 and 89 mL min-1 1.73 m-2 when estimated by the Zappitelli equation, combining creatinine and cystatin C. Of all patients, 20.0% (95% CI 12.1-26.7) had orthostatic proteinuria, and none had persistent albuminuria.

CONCLUSIONS

There was no evidence of CKD in the present population aged 10-18 years. The significance of an eGFR between 60 and 90 mL min-1 1.73 m-2 is not concordant for this age range and requires further investigations.

Acute Kidney Injury after Congenital Heart Disease Surgery: A Single-Center Experience in a Low- to Middle-Income Country

Background Acute kidney injury (AKI) is a commonly recognized clinical problem after congenital heart disease (CHD) surgery. Increased perioperative morbidity, development of chronic kidney disease, and increased mortality are the major concerns. We investigated frequency, risk factors, and outcomes of AKI after CHD surgery at our hospital. Methods This study was a retrospective analytic review conducted from January 2013 to October 2016 on patients aged between 1 month and 45 years who underwent cardiopulmonary bypass (CPB) for CHD surgery. The modified Kidney Disease Improving Global Outcomes criteria based on serum creatinine value was adopted to diagnose AKI. We assessed AKI frequency and its staging, and outcomes as AKI resolution, length of stay, and mortality. Stages II and III (plasma creatinine level two or more times the baseline) were labeled as severe AKI. Univariate and multivariate logistic regression analyses were conducted, and results were reported as mean with standard deviation and as frequencies with percentage. Odds ratios (ORs) with 95% confidence intervals (CIs) were reported for factors associated with the development of AKI. Results Of the 840 patients who underwent CHD surgery, 237 (28%) developed AKI. AKI stages II1 and III were seen in 101 (42%) and 103 (43%) patients, respectively. Prolonged CPB time > 120 minutes (adjusted OR [AOR]: 1.87; 95% CI: 1.22-2.88; p = 0.004) and hemoglobin > 16 gm/dL (AOR: 1.80; 95% CI: 1.16-2.78; p = 0.008) were associated with the development of AKI on multivariate analysis. AKI resolved spontaneously in 222 (94%) patients, and 10 (4%) patients who developed AKI died. Conclusions Most patients with AKI showed spontaneous resolution. Prolonged CPB time and increased hemoglobin were found to be significant risk factors. Our study found spontaneous resolution of AKI in most cases. However, preplanning and careful monitoring in patients with expected prolonged CPB time and increased baseline hemoglobin can prevent and identify AKI at an early stage.

Evaluation and Management of the Child and Adult With Fontan Circulation: A Scientific Statement From the American Heart Association

It has been 50 years since Francis Fontan pioneered the operation that today bears his name. Initially designed for patients with tricuspid atresia, this procedure is now offered for a vast array of congenital cardiac lesions when a circulation with 2 ventricles cannot be achieved. As a result of technical advances and improvements in patient selection and perioperative management, survival has steadily increased, and it is estimated that patients operated on today may hope for a 30-year survival of >80%. Up to 70 000 patients may be alive worldwide today with Fontan circulation, and this population is expected to double in the next 20 years. In the absence of a subpulmonary ventricle, Fontan circulation is characterized by chronically elevated systemic venous pressures and decreased cardiac output. The addition of this acquired abnormal circulation to innate abnormalities associated with single-ventricle congenital heart disease exposes these patients to a variety of complications. Circulatory failure, ventricular dysfunction, atrioventricular valve regurgitation, arrhythmia, protein-losing enteropathy, and plastic bronchitis are potential complications of the Fontan circulation. Abnormalities in body composition, bone structure, and growth have been detected. Liver fibrosis and renal dysfunction are common and may progress over time. Cognitive, neuropsychological, and behavioral deficits are highly prevalent. As a testimony to the success of the current strategy of care, the proportion of adults with Fontan circulation is increasing. Healthcare providers are ill-prepared to tackle these challenges, as well as specific needs such as contraception and pregnancy in female patients. The role of therapies such as cardiovascular drugs to prevent and treat complications, heart transplantation, and mechanical circulatory support remains undetermined. There is a clear need for consensus on how best to follow up patients with Fontan circulation and to treat their complications. This American Heart Association statement summarizes the current state of knowledge on the Fontan circulation and its consequences. A proposed surveillance testing toolkit provides recommendations for a range of acceptable approaches to follow-up care for the patient with Fontan circulation. Gaps in knowledge and areas for future focus of investigation are highlighted, with the objective of laying the groundwork for creating a normal quality and duration of life for these unique individuals.

Risk Factors for Recurrent Acute Kidney Injury in Children Who Undergo Multiple Cardiac Surgeries: A Retrospective Analysis

OBJECTIVES

Determine the risk factors for repeated episodes of acute kidney injury in children who undergo multiple cardiac surgical procedures.

DESIGN

Single-center retrospective chart review.

SETTING

Cardiac ICU at a quaternary pediatric care center.

PATIENTS

Birth to 18 years who underwent at least two cardiac surgical procedures with cardiopulmonary bypass.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One-hundred eighty patients underwent two cardiac surgical procedures and 89 underwent three. Acute kidney injury was defined by the Kidney Disease: Improving Global Outcomes serum creatinine criteria. Acute kidney injury frequency was 26% (n = 46) after surgery 1, 20% (n = 36) after surgery 2, and 24% (n = 21) after surgery 3, with most acute kidney injury occurring on postoperative days 1 and 2. The proportion of patients with severe acute kidney injury increased from surgery 1 to surgery 3. Patients with acute kidney injury had a significantly longer duration of ventilation and length of stay after each surgery. The odds of acute kidney injury after surgery 3 was 2.40 times greater if acute kidney injury was present after surgery 1 or 2 (95% CI, 1.26-4.56; p = 0.008) after adjusting for confounders. The time between surgeries was not significantly associated with acute kidney injury (p = 0.85).

CONCLUSIONS

In a heterogeneous population of pediatric patients with congenital heart disease undergoing multiple cardiopulmonary bypass surgeries, odds of acute kidney injury after a third surgery was increased by the presence of acute kidney injury after prior procedures. Time between surgery did not play a role in increasing odds of acute kidney injury. Further studies in a larger multicenter investigation are necessary to confirm these findings.

Comparison of creatinine and cystatin C for estimation of glomerular filtration rate in pediatric patients after Fontan operation

BACKGROUND

There are several limitations when using creatinine to estimate glomerular filtration rate, especially in children with chronic medical conditions who are at high risk of kidney dysfunction. Cystatin C has been the recent focus of research as a replacement biomarker for creatinine. Our objective was to compare the 2 biomarkers in pediatric single-ventricle heart disease patients who have undergone the Fontan operation. We hypothesized that there would be poor correlation and agreement between the 2 estimates of renal function.

METHODS

This was a single center retrospective chart review of 20 patients who had previously undergone Fontan operation. Demographic and clinical data were collected from medical records. Blood samples were collected as part of routine clinical care and simultaneously measured for serum creatinine and cystatin C. Glomerular filtration rate was calculated using the creatinine-based bedside Schwartz formula and cystatin C-based Zapatelli equation. Spearman correlation and Bland-Altman analysis were used to assess correlation and agreement.

RESULTS

The median Schwartz-derived estimated glomerular filtration rate was 98.94 mL/min/1.73 m² while the median Zappitelli-derived estimated glomerular filtration rate was 84.76 mL/min/1.73 m² . The mean difference was -19.27 suggesting poor agreement. There was weak to moderate correlation between the Schwartz and cystatin C estimated glomerular filtration rate.

CONCLUSION

The bedside Schwartz formula may be an overestimate of glomerular filtration rate in pediatric single-ventricle heart disease patients who have undergone the Fontan operation. While larger studies are necessary, cystatin C is a promising biomarker to replace creatinine and better estimate kidney function in this population.

Impact of the Fontan Operation on Organ Systems

In patients having undergone the Fontan operation, besides the well discussed changes in the cardiac, pulmonary and gastrointestinal system, alterations of further organ systems including the hematologic, immunologic, endocrinological and metabolic are reported. As a medical adjunct to Fontan surgery, the systematic study of the central role of the liver as a metabolizing and synthesizing organ should allow for a better understanding of the pathomechanism underlying the typical problems in Fontan patients, and in this context, the profiling of endocrinological and metabolic patterns might offer a tool for the optimization of Fontan follow-up, targeted monitoring and specific adjunct treatment.

Acute kidney injury after pediatric cardiac surgery

Acute kidney injury (AKI) is a common complication of pediatric cardiac surgery and is associated with increased morbidity and mortality. Literature of AKI after pediatric cardiac surgery is comprehensively reviewed in terms of incidence, risk factors, biomarkers, treatment and prognosis. The novel RIFLE (pediatric RIFLE for pediatrics), Acute Kidney Injury Network (AKIN) and Kidney Disease Improving Global Outcomes (KDIGO) criteria have brought about unified diagnostic standards and comparable results for AKI after cardiac surgery. Numerous risk factors, either renal or extrarenal, can be responsible for the development of AKI after cardiac surgery, with low cardiac output syndrome being the most pronounced predictor. Early fluid overload is also crucial for the occurrence of AKI and prognosis in pediatric patients. Three sensitive biomarkers, neutrophil gelatinase-associated lipocalin, cystatin C (CysC) and liver fatty acid-binding protein, are regarded as the earliest (increase at 2-4 h), and another two, kidney injury molecule-1 and interleukin-18 represent the intermediate respondents (increase at 6-12 h after surgery). To ameliorate the cardiopulmonary bypass techniques, improve renal perfusion and eradicate the causative risk factors are imperative for the prevention of AKI in pediatric patients. The early and intermediate biomarkers are helpful for an early judgment of occurrence of postoperative AKI. Improved survival has been achieved by prevention, renal support and modifications of hemofiltration techniques. Further development is anticipated in small children.

Nephrotoxin exposure and acute kidney injury in critically ill children undergoing congenital cardiac surgery

BACKGROUND

Though acute kidney injury (AKI) is often multifactorial, investigators are now emphasizing the specific contribution of nephrotoxins. This study examines the epidemiology of nephrotoxin exposure and nephrotoxin-associated AKI among children undergoing congenital heart surgery (CHS).

METHODS

This is a retrospective cohort study of children admitted following CHS between June 1, 2014, and September 30, 2014. Nephrotoxins were defined according to the Nephrotoxic Injury Negated by Just-in-time-Action (NINJA) collaborative; high nephrotoxin exposure was defined as receipt of ≥ 3 nephrotoxins concurrently. AKI was diagnosed according to KDIGO creatinine criteria. Severe AKI was defined as KDIGO stage ≥ 2. Poisson models were used to compute adjusted relative risk (aRR) of high nephrotoxin exposure for AKI.

RESULTS

One hundred fifty-four children (median age 20.4 months, IQR 2.3-59.5) were included. One hundred thirty-one (85.1%) received at least one nephrotoxin; 32 (20.8%) received ≥ 3 nephrotoxins. The most commonly administered medications were ketorolac (n = 74, 48.1%), aspirin (n = 62, 40.3%), ibuprofen (n = 51, 33.1%), vancomycin (n = 39, 25.3%), piperacillin/tazobactam (n = 35, 22.7%), and enalapril (n = 14, 9.1%). AKI occurred more commonly in those exposed to ≥ 3 nephrotoxins (62.5 vs. 50.8%); this was not statistically significant after adjusting for confounders (aRR = 1.2, 95% CI 0.9-1.7). Severe AKI was similar between those with and without high nephrotoxin exposure (21.9 vs. 19.7%, p = 0.78).

CONCLUSIONS

Nephrotoxin use is common following pediatric CHS. While we found no association between high nephrotoxin exposure and AKI, this may be related to the multifactorial nature of AKI in this population. For many common nephrotoxins, less injurious agents exist and nephrotoxin exposure may represent a modifiable risk factor for AKI.

Building an Adult Congenital Heart Program: Critical Components and Important Allies

Purpose of the Review

The purpose of this review is to illustrate specific challenges and opportunities in the building of an adult congenital heart disease (ACHD) program and to highlight critical components and important allies.

Recent Findings

With more than 1.4 million adults with congenital heart disease in the USA alone, access to specialized, compassionate, high-quality comprehensive care requires a shift toward more aggressive expansion of ACHD care, especially in the context of sparse ACHD provider representation in the vast majority of adult medical centers.

Summary

The effective build of an ACHD program requires measured escalation in management of ACHD complexity matched with cultivation of key resources and clinical services ranging from congenital cardiac surgery and interventional cardiology to acquired heart disease as well as partnerships with non-cardiac specialists. By reframing ACHD care as a shared goal between patients, providers, hospitals, pharmaceutical and device industry, and payers, a potent business model can be built around the developing ACHD program to facilitate acquisition of these key resources.

The role of fluid overload in the prediction of outcome in acute kidney injury

Our understanding of the epidemiology and the impact of acute kidney injury (AKI) and fluid overload on outcomes has improved significantly over the past several decades. Fluid overload occurs commonly in critically ill children with and without associated AKI. Researchers in pediatric AKI have been at the forefront of describing the impact of fluid overload on outcomes in a variety of populations. A full understanding of this topic is important as fluid overload represents a potentially modifiable risk factor and a target for intervention. In this state-of-the-art review, we comprehensively describe the definition of fluid overload, the impact of fluid overload on kidney function, the impact of fluid overload on the diagnosis of AKI, the association of fluid overload with outcomes, the targeted therapy of fluid overload, and the impact of the timing of renal replacement therapy on outcomes.

Diagnosis and Management of Noncardiac Complications in Adults With Congenital Heart Disease: A Scientific Statement From the American Heart Association

Life expectancy and quality of life for those born with congenital heart disease (CHD) have greatly improved over the past 3 decades. While representing a great advance for these patients, who have been able to move from childhood to successful adult lives in increasing numbers, this development has resulted in an epidemiological shift and a generation of patients who are at risk of developing chronic multisystem disease in adulthood. Noncardiac complications significantly contribute to the morbidity and mortality of adults with CHD. Reduced survival has been documented in patients with CHD with renal dysfunction, restrictive lung disease, anemia, and cirrhosis. Furthermore, as this population ages, atherosclerotic cardiovascular disease and its risk factors are becoming increasingly prevalent. Disorders of psychosocial and cognitive development are key factors affecting the quality of life of these individuals. It is incumbent on physicians who care for patients with CHD to be mindful of the effects that disease of organs other than the heart may have on the well-being of adults with CHD. Further research is needed to understand how these noncardiac complications may affect the long-term outcome in these patients and what modifiable factors can be targeted for preventive intervention.

Systemic right ventricular morphology in the early postoperative course after extracardiac Fontan operation: is there still a need for special care?

Objectives

We aimed to compare early postoperative outcome after extracardiac (EC) Fontan operation between patients with right (RV) or left (LV) systemic ventricles.

Methods

In total, 173 consecutive patients (median age 4 years, median weight 14 kg) underwent EC Fontan between 1995 and 2013. Pre- and intraoperative data as well as detailed postoperative haemodynamic variables were compared between patients with LV [ n  = 109 (63%)] and RV [ n  = 64 (37%)].

Results

: RV patients showed significantly lower mean arterial (median 55 vs 59 mmHg, P  = 0.04), higher atrial (median 8 vs 6 mmHg, P  = 0.03) and comparable pulmonary pressure (median 14 vs 14 mmHg, P  = 0.7) as well as lower mean systemic perfusion pressure (median 39 vs 43 mmHg, P  = 0.03) on Day 0 after EC Fontan. They suffered from longer intubation time (median 18 vs 12 h, P  = 0.008), higher incidence of ascites (46% vs 28%, P  = 0.04) and need for dialysis (21% vs 4%, P  = 0.003). Prolonged inotropic support (25% vs 8%, P  = 0.02) and pharmacological treatment to reduce pulmonary vascular resistance (71% vs 53%, P  = 0.002) were more often used in RV patients and they showed more often supraventricular tachyarrhythmia (27% vs 5%, P  < 0.001) and a longer intensive care unit-stay (median 4 vs 3 days, P  = 0.03). However, early mortality, need for Fontan takedown, use of mechanical circulatory support, pleural effusions and hospital stay were not significantly different between both groups.

Conclusions

Patients with systemic RV demonstrate higher morbidity in the early postoperative course compared with patients with systemic LV anatomy and require intensified postoperative management to avoid postoperative Fontan failure.

Hemodynamic Profile of Acute Kidney Injury Following the Fontan Procedure: Impact of Renal Perfusion Pressure

BACKGROUND

Acute kidney injury (AKI) is common following cardiopulmonary bypass. Fontan completion may result in systemic venous hypertension and low cardiac output, reducing renal perfusion pressure (RPP) and further increasing the risk of AKI. We investigated the incidence and risk factors for post-Fontan AKI.

METHODS

Single-center retrospective study of children undergoing Fontan completion from 2005 to 2012. Demographic and hemodynamic variables were assessed for association with AKI. Subgroup analysis was performed on patients with high-grade AKI (creatinine increase of ≥2.0 × baseline). Vital sign data were collected hourly for the first postoperative day.

RESULTS

A total of 186 patients underwent Fontan at 3.1 (2.5-3.8) years of age and 13.5 kg (12.2-15.1). Acute kidney injury occurred in 97 (52%) patients, with high-grade AKI in 52 (28%). Univariate analysis identified reduced RPP in patients with AKI compared to those without AKI, 50 (45-56) mm Hg versus 58 (54-61) mm Hg ( P < .0001), due to lower mean arterial blood pressure, 63 (60-69) versus 70 (66-73) mm Hg ( P < .0001), and higher central venous pressure, 14 (12-16) versus 13 (11-14) mm Hg, ( p < .0001). Multivariable logistic regression and classification tree analyses further identified elements of RPP as significant predictors of AKI, especially high-grade AKI. Postoperative intubation was linked to AKI development. Patients with AKI had decreased postoperative urine output with increased colloid requirements, duration of chest tube insertion, and hospital length of stay.

CONCLUSION

Acute kidney injury occurs frequently following the Fontan procedure. Associated factors include reduced RPP, high colloid requirements, and postoperative intubation. Targeted hemodynamic interventions may serve to reduce the incidence of post-Fontan AKI.

Acute Kidney Injury in Patients Undergoing the Extracardiac Fontan Operation With and Without the Use of Cardiopulmonary Bypass

OBJECTIVES

To describe the prevalence and risk factors for acute kidney injury in patients undergoing the extracardiac Fontan operation with and without cardiopulmonary bypass, and to determine whether acute kidney injury is associated with duration of mechanical ventilation, cardiovascular ICU and hospital postoperative length of stay, and early mortality.

DESIGN

Single-center retrospective cohort study.

SETTING

Pediatric cardiovascular ICU, university-affiliated children's hospital.

PATIENTS

Patients with a preoperative creatinine before undergoing first-time extracardiac Fontan between January 1, 2004, and April 30, 2012.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Acute kidney injury occurred in 55 of 138 patients (39.9%), including 41 (29.7%) with stage 1, six (4.4%) with stage 2, and eight (5.8%) with stage 3 acute kidney injury. Cardiopulmonary bypass was strongly associated with a higher risk of any acute kidney injury (adjusted odds ratio, 4.8 [95% CI, 1.4-16.0]; p = 0.01) but not stage 2/3 acute kidney injury. Lower renal perfusion pressure on the day of surgery (postoperative day, 0) was associated with a higher risk of stage 2/3 acute kidney injury (adjusted odds ratio, 1.2 [95% CI, 1.0-1.5]; p = 0.03). Higher vasoactive-inotropic score on postoperative day 0 was associated with a higher risk for stage 2/3 acute kidney injury (adjusted odds ratio, 1.9 [95% CI, 1.0-3.4]; p = 0.04). Stage 2/3 acute kidney injury was associated with longer cardiovascular ICU length of stay (mean, 7.3 greater d [95% CI, 3.4-11.3]; p < 0.001) and hospital postoperative length of stay (mean, 6.4 greater d [95% CI, 0.06-12.5]; p = 0.04).

CONCLUSIONS

Postoperative acute kidney injury in patients undergoing the extracardiac Fontan operation is common and is associated with lower postoperative renal perfusion pressure and higher vasoactive-inotropic score. Cardiopulmonary bypass was strongly associated with any acute kidney injury, although not stage 2/3 acute kidney injury. Stage 2/3 acute kidney injury is a compelling risk factor for longer cardiovascular ICU and hospital postoperative length of stay. Increased attention to and management of renal perfusion pressure may reduce postoperative acute kidney injury and improve outcomes.

Assessment of central venous physiology of Fontan circulation using peripheral venous pressure

OBJECTIVE

Elevated central venous pressure is a major cause of morbidity and mortality after the Fontan operation. The difference between mean circulatory filling pressure and central venous pressure, a driving force of venous return, is important in determining dynamic changes in central venous pressure in response to changes in ventricular properties or loading conditions. Thus, noninvasive central venous pressure and mean circulatory filling pressure estimation may contribute to optimal management in patients undergoing the Fontan operation. We tested the hypothesis that central venous pressure and mean circulatory filling pressure in those undergoing the Fontan operation can be simply estimated using peripheral venous pressure and arm equilibrium pressure, respectively.

METHODS

This study included 30 patients after the Fontan operation who underwent cardiac catheterization (median 8.6, 3.4-42 years). Peripheral venous pressure was measured at the peripheral vein in the upper extremities. Mean circulatory filling pressure was calculated by the changes of arterial pressure and central venous pressure during the Valsalva maneuver. Arm equilibrium pressure was measured as equilibrated venous pressure by rapidly inflating a blood pressure cuff to 200 mm Hg.

RESULTS

Central venous pressure and peripheral venous pressure were highly correlated (central venous pressure = 1.6 + 0.68 × peripheral venous pressure, R = 0.86, P < .0001). Stepwise multivariable regression analysis showed that only peripheral venous pressure was a significant determinant of central venous pressure. Central venous pressure was accurately estimated using regression after volume loading by contrast injection (R = 0.82, P < .0001). In addition, arm equilibrium pressure measurements were highly reproducible and robustly reflected invasively measured mean circulatory filling pressure (mean circulatory filling pressure = 9.1 + 0.63 × arm equilibrium pressure, R = 0.88, P < .0001).

CONCLUSIONS

Central venous pressure and mean circulatory filling pressure can be noninvasively estimated by peripheral venous pressure and arm equilibrium pressure, respectively. This should help clarify unidentified Fontan pathophysiology and the mechanisms of Fontan failure progression, thereby helping construct effective tailor-made approaches to prevent Fontan failure.

A Retrospective Analysis of the Influence of Ventricular Morphology on the Perioperative Outcomes After Fontan Surgery

OBJECTIVES

The objectives of this study were to evaluate the effect of ventricular morphology on perioperative outcomes during Fontan surgery.

DESIGN

Retrospective cohort study.

SETTING

Single standing, not-for-profit pediatric hospital.

PARTICIPANTS

A total of 72 patients who underwent Fontan surgery using cardiopulmonary bypass without aortic cross-clamp between January 1, 2009 and December 31, 2014.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The patients were divided into 3 categories depending on their single-ventricle lesions: (1) LV group (n = 20): left dominant and hypoplastic right ventricle; (2) RV group (n = 37): right dominant and hypoplastic left ventricle; and (3) BV group (n = 15): biventricular or indeterminate dominance. Perioperative major adverse events were collected based on the Society of Thoracic Surgeons database. The need for perioperative allogeneic blood transfusions also was determined. The mean age was 3.3±1.7 years and the mean weight was 13.6±4.0 kg. All patients had extracardiac lateral tunnel or conduit Fontan procedures. Sixty-nine of the patients (96%) underwent tracheal extubation in the operating room. Anesthesia, surgery, and CPB times were 326±68, 239±73, and 70±41 minutes, respectively. Eleven patients (15%) required allogeneic blood products intraoperatively, while 30 patients (42%) required allogeneic blood products during the perioperative period. Length of cardiac intensive care unit stay and hospital stay (median [IQR]) were 1 [1,2] and 12 [9,18] days, respectively. There was no mortality and no significant differences between groups in major postoperative complications, anesthetic or surgical variables.

CONCLUSIONS

No difference in the immediate perioperative outcomes was noted based on ventricular morphology.

Catheter-measured Hemodynamics of Adult Fontan Circulation: Associations with Adverse Event and End-organ Dysfunctions

BACKGROUND

In heart failure, a high systemic vascular resistance index (SVRI), high central venous pressure (CVP), and low cardiac index (CI) predict poor outcomes. Conversely, late hemodynamic manifestations of failing Fontan circulation and associations with end-organ dysfunction are not well understood.

METHODS

A retrospective review of right-heart catheterization data of adult Fontan patients between 2002 and 2014 was conducted. Relationships between hemodynamic variables and serious adverse events (death or heart transplant) were examined using the Cox proportional hazard analysis. Correlations between the hemodynamic measurements and signs of end-organ dysfunction (MELD-XI, Child-Pugh, VAST score, estimated glomerular filtration rate [eGFR]) were analyzed.

RESULTS

Sixty post-Fontan patients (85% systemic left ventricle, 40% atriopulmonary Fontan, mean age of 28 years, and mean time since Fontan operation of 21.9 years) were included. At baseline, those with an event were statistically younger, had lower transcutaneous oxygen saturations, were more likely to have an atriopulmonary Fontan, and were more likely to have a pacemaker. Eighteen experienced a cardiovascularly significant event. Using univariate analysis to compare the event and nonevent groups, mean CI was 2.8 ± 0.9 vs. 2.4 ± 0.5 L/min/m² (P = .004), and CVP was 18.6 ± 6.5 vs. 16.1 ± 4.3 mmHg (P = .03). However, the statistical significances did not persist in the multivariate model. Higher CVP and pulmonary capillary wedge pressure (PCWP) were associated with higher MELD-XI and Child-Pugh scores, and the VAST score was only associated with PCWP.

CONCLUSIONS

Symptomatic adult Fontan patients who experienced an event manifested with a higher CI and CVP, although the multivariate Cox proportional hazard analysis did not yield any significant associations. The presences of hepatic dysfunction and portal venous outflow obstruction were associated with a higher CVP and PCWP. Renal dysfunction was prevalent but no statistically significant association between the hemodynamic measurements was identified, although trends toward a higher CVP and transpulmonary gradient were identified.