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

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.

Perturbations of tryptophan catabolism via the kynurenine pathway are associated with stage 2 postoperative outcomes in single ventricle heart disease

Preliminary evidence suggests perturbations of the kynurenine pathway (KP) of tryptophan metabolism in infants with single ventricle heart disease (SVHD). In 72 infants with SVHD undergoing stage 2 palliation (S2P) and 41 controls, we quantified serum KP metabolite concentrations via tandem mass spectroscopy pre-S2P and post-S2P at 2, 24, and 48 h and assessed metabolite relationships with post-S2P outcomes (length of stay, hypoxemia burden, and intubation duration). Pre-S2P, SVHD infants had lower tryptophan and serotonin levels and higher kynurenic acid, 3-hydroxykynurenine, and picolinic acid levels than controls. Post-S2P, metabolites peaked at 2 h, with return to baseline by 48 h for all except kynurenic acid, which remained elevated. Metabolite concentrations pre-S2P were poorly associated with outcomes. A lower serotonin peak 2 h post-S2P was associated with longer length of stay and intubation duration. Multiple metabolites at 24 and 48 h correlated with outcomes; notably, elevated kynurenic acid was associated with worse results for all three outcomes. Our results confirm that interstage SVHD infants have altered KP activity compared to controls. Further, the link between outcomes and KP metabolites post-S2P-but not at baseline-demonstrates that acute, perioperative changes in tryptophan catabolism may be more important to tolerating S2P physiology than chronic interstage changes.

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.

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.

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.

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.

Cardiorenal Syndrome

Cardiorenal syndrome (CRS) describes a specific acute and chronic clinical picture in which the heart or the kidney are primarily dysfunctioning and secondarily affect each other. CRS is divided into five classes: acute and chronic CRS, acute and chronic renocardiac syndromes, and secondary dysfunction of heart and kidneys. This article specifically details the classification and the epidemiology, some risk factors, and the pathophysiology of CRS. Some emerging aspects of CRS are also discussed, such as CRS in patients with end-stage heart failure, with mechanical ventricular assistance, and after heart transplantation. Finally, some aspects of pediatric CRS are detailed.

Comparison of Postoperative Acute Kidney Injury Between Laparoscopic and Laparotomy Procedures in Elderly Patients Undergoing Colorectal Surgery

OBJECTIVES

Postoperative acute kidney injury (AKI) has an unfavorable impact on both short-term and long-term outcomes. The aim of this retrospective study was to compare the incidence of postoperative AKI between laparoscopic and laparotomy procedures in elderly patients undergoing colorectal surgery.

METHODS

Medical records of elderly (65 y and older) patients who underwent colorectal cancer surgery between May 2016 and July 2018 at our tertiary hospital were reviewed. Patients with Union Internationale Contre le Cancer (UICC) stage II and III colorectal cancer, without neoadjuvant treatment, were divided into laparoscopic procedure group and laparotomy group. AKI, determined by the Acute Kidney Injury Network criteria, was compared between the 2 groups, before and after propensity matching. Multivariable analysis was made to identify independent risk factors of AKI.

RESULTS

In all, 285 patients met the study inclusion criteria. Postoperative AKI occurred only in 16 patients from the laparotomy group (n=212). The incidence of AKI was significantly lower in the laparoscopic procedure group (n=73) compared with the laparotomy group (0% vs. 7.5%; P=0.015). Seventy-three patients who underwent laparoscopic surgery were matched with 73 of 212 patients who underwent open surgery, by using propensity score analysis, and the incidence of AKI in the 2 groups was similar (0% vs. 8.3%; P=0.028). Multivariable analysis showed that intraoperative metaraminol dose >1 mg (odds ratio=2.742, P=0.042) is an independent risk factor for postoperative AKI.

CONCLUSION

In elderly patients, the incidence of AKI after colorectal cancer surgery is lower in the laparoscopic procedure group, maybe related to hemodynamic stability and less vasoconstriction.

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.