Mortality and associated risk factors in perioperative acute kidney injury treated with continuous renal replacement therapy

Behind the scenes: Key lessons learned from the RELIEVE-AKI clinical trial

Continuous kidney replacement therapy (CKRT) is commonly used to manage critically ill patients with severe acute kidney injury. While recent trials focused on the correct dosing and timing of CKRT, our understanding regarding the optimum dose of net ultrafiltration is limited to retrospective data. The Restrictive versus Liberal Rate of Extracorporeal Volume Removal Evaluation in Acute Kidney Injury (RELIEVE-AKI) trial has been conducted to assess the feasibility of a prospective randomized trial in determining the optimum net ultrafiltration rate. This paper outlines the relevant challenges and solutions in implementing this complex ICU-based trial. Several difficulties were encountered, starting with clinical issues related to conducting a trial on patients with rapidly changing hemodynamics, low patient recruitment rates, increased nursing workload, and the enormous volume of data generated by patients undergoing prolonged CKRT. Following several brainstorming sessions, several points were highlighted to be considered, including the need to streamline the intervention, add more flexibility in the trial protocols, ensure comprehensive a priori planning, particularly regarding nursing roles and their compensation, and enhance data management systems. These insights are critical for guiding future ICU-based dynamically titrated intervention trials, leading to more efficient trial management, improved data quality, and enhanced patient safety.

Renal recovery in cardiac surgery patients requiring postoperative renal-replacement therapy

OBJECTIVE

Renal failure after cardiac surgery is associated with increased morbidity and mortality. There is a lack of data examining the rate of renal recovery after patients have started dialysis following cardiac surgery. We aimed to determine the frequency of and time to renal recovery of patients requiring dialysis after cardiac surgery.

METHODS

All patients who developed new-onset renal failure requiring dialysis following cardiac surgery at our institution from 2011 to 2022 were included. Renal recovery, time to renal recovery, and mortality at 1 year were merged with patients' Society of Thoracic Surgeons Adult Cardiac Surgery Database files. Kaplan-Meier analysis was used to predict time to renal recovery; we censored patients who died or were lost to follow up. Cox regression was used for risk-adjustment.

RESULTS

A total of 312 patients were included in the final analysis. Mortality during index hospital admission was 33% (n = 105), and mortality at 1 year was 45% (n = 141). Of those surviving at 1 year, 69% (n = 118) remained renally recovered. Median renal recovery time was 56 (37-74) days. Accounting for mortality as a competing risk, 51% of patients were predicted to achieve renal recovery. Increasing age (hazard ratio, 0.98; 0.514-0.94, P < .026) and increasing total packed red blood cells (hazard ratio, 0.0958; 0.937-0.987, P < .001) received were found to be significant negative predictors of renal recovery in the Fine-Gray model for subhazard distribution.

CONCLUSIONS

More than two-thirds of patients with renal failure who survived the perioperative period had renal recovery within 1 year after surgery. Recovery was driven primarily by postoperative complications rather than comorbidities and intraoperative factors, suggesting renal failure in the postoperative cardiac surgery patient surviving to discharge is unlikely to be permanent.

The association between albumin corrected anion gap and ICU mortality in acute kidney injury patients requiring continuous renal replacement therapy

The relationship between albumin corrected anion gap (ACAG) and mortality in acute kidney injury (AKI) patients who received continuous renal replacement therapy (CRRT) has not been investigated in any previous studies. This study aimed to investigate the relationship between ACAG at CRRT initiation and all-cause mortality among these patients in the intensive care unit (ICU). Patients diagnosed with AKI and treated with CRRT in the ICU from the Medical Information Mart for Intensive Care-IV version 1.0 (MIMIC IV) database and Huzhou Central Hospital were retrospectively enrolled. Participants were divided into two groups: the normal ACAG group (12-20 mmol/L) and high ACAG group (> 20 mmol/L). The Kaplan-Meier method and log-rank test were used to compare the survival rate between the two groups. Restricted cubic spine (RCS) and Cox proportional-hazards models were utilized to analyze the relationship between ACAG at CRRT initiation and ICU all-cause mortality of these patients. A total of 708 patients met the inclusion criteria in the study. The all-cause mortality of these patients during ICU hospitalization was 41.95%. Patients in the high ACAG group exhibited significantly higher ICU all-cause mortality rate than patients in the normal ACAG group (all P < 0.001). The Kaplan-Meier survival curves showed that the normal ACAG group had a higher ICU cumulative survival rate than the high ACAG group (log-rank test, χ₁²= 13.620, χ₂² = 12.460, both P < 0.001). In the multivariate COX regression analyses, patients with higher ACAG (> 20 mmol/L) levels at the time of CRRT initiation in the MIMIC IV database and Huzhou Central Hospital were significantly correlated with ICU all-cause mortality after adjusting multiple potential confounding factors with hazard ratios of 2.852 (95% CI 1.718-4.734) and 2.637(95% CI 1.584-4.389), respectively. In critically AKI patients who undergo CRRT, higher ACAG (> 20 mmol/L) level at the initiation of CRRT was significantly correlated with ICU all-cause mortality. Therefore, clinicians should pay more attention to those patients with a higher ACAG value.

Risk factors for the in-hospital mortality of CRRT-therapy patients with cardiac surgery-associated AKI: a single-center clinical study in China

OBJECTIVE

We retrospectively analyzed risk factors on in-hospital mortality in CRRT-therapy patients with open cardiac surgery (CS)-induced acute kidney injury (AKI), to provide the clinical basis for predicting and lowering the in-hospital mortality after CS.

METHODS

84 CS-AKI patients with CRRT were divided into survival and death groups according to discharge status, and the perioperative data were analyzed with R version 4.0.2.

RESULTS

There were significant differences between the two groups, including: urea nitrogen, Sequential Organ Failure Assessment (SOFA) score and vasoactive-inotropic score (VIS) on the first day after operation; VIS just before CRRT; SOFA score and negative balance of blood volume 24 h after CRRT; the incidence rate of bleeding, severe infection and MODS after operation; and the interval between AKI and CRRT. Univariate logistic regression analysis showed that SOFA score and VIS on the first day after operation; VIS just before CRRT; VIS and negative balance of blood volume 24 h after CRRT; the incidence rate of bleeding, infection and multiple organ dysfunction syndrome (MODS) after operation; bootstrap resampling analysis showed that SOFA score and VIS 24 h after CRRT, as well as the incidence of bleeding after operation were the independent risk factors.

CONCLUSION

Maintaining stable hemodynamics and active prevention of bleeding are expected to decrease the in-hospital mortality.

Recovery of Renal Function in Clinical Patients with Acute Kidney Injury: Impact on Mortality

Objective: To assess the different renal function recovery patterns and their impact on the mortality of non-critical patients with hospital-acquired Acute Kidney Injury. Design: A prospective cohort study was conducted from January 2017 to December 2019. Methods: The patients included were those with Acute Kidney Injury acquired during their hospitalization, identified from Kidney Disease: Improving Global Outcomes (KDIGO). Renal function recovery was calculated through the serum creatinine ratio in relation to baseline creatinine at the renal function evaluation moment. A descriptive analysis of the results was performed, and the Backward method was adopted for the multivariate analysis. Results: One-thousand five-hundred and forty-six patients were evaluated in the medical clinic and 202 (13.06%) were identified to have Acute Kidney Injury; among them, renal function recovery varied over the six months of follow-up with greater expressiveness in the second and third months (from 61.02% to 62.79%). Recovery was a protective factor against in-hospital death in the first (OR 0.24; 95% CI 0.09–0.61; p-value = 0.038) and sixth month of follow-up (OR 0.24; 95% CI 0.09–0.61; p-value = 0.003). Conclusions: The incidence of renal function recovery varied throughout the six months of follow-up and reached progressively high levels from the second to the third months. Renal recovery was a protective factor against mortality during the follow-up period.