Acute renal injury is a frequent complication after cardiac surgery that necessitates additional treatment and increases mortality. To apply measures for optimizing renal function in a well-directed and effective way, it is most important to detect acute kidney injury at an early stage. The present study compares three markers of renal tubular function for detection of acute renal injury according to the acute kidney injury (Acute Kidney Injury Network (AKIN)) criteria. Urinary concentration of the tubular markers neutrophil glucosaminidase-associated lipocalin (NGAL), α1-microglobulin (α1MG), and cystatin C (CysC) were measured in 50 patients after elective cardiac surgery. Samples were taken once preoperatively and postoperatively every 12 h for up to 5 days. Based on the highest recorded postoperative AKIN score, patients were divided into two groups (AKIN 0 and AKIN 1-3). Statistical analysis was done for marker concentrations at three time points: preoperative, after admission to the intensive care unit (ICU), and at the highest postoperative AKIN level. In addition, all concentrations of marker proteins were multiplied by the ratio of creatinine concentrations in serum and urine; these products were also analyzed statistically. In this way, we were able to eliminate the influence of varying degrees of diuresis on marker concentrations. As early as at admission to the ICU, all marker proteins showed significantly higher concentrations compared with preoperative values. However, differences in concentrations between the groups AKIN 0 and AKIN 1-3 were only statistically significant for NGAL. Using receiver operating characteristic (ROC) analysis, we found that only NGAL concentrations were suitable for detecting acute kidney injury with adequate sensitivity and specificity (area under the curve (AUC)=0.773). Levels of α1MG yielded a comparable accuracy when urinary concentrations were multiplied by the serum/urine creatinine ratio (AUC=0.712). An increase in urinary NGAL is an early sign of acute kidney injury after cardiac surgery. After multiplication by the serum/urine creatinine ratio, urinary α1MG is also suitable for detection of acute kidney injury at an early stage.

Preoperative assessment of risk factors for postoperative acute renal failure (ARF) is a key point in the management of cardiac surgery patients. A reliable evaluation of individual risk permits the efficient application of prophylactic and therapeutic measures to patients with increased risk of ARF. In 2005, Thakar published a scoring system to determine the ARF risk prior to surgery. The score allowed calculation of the incidence of postoperative ARF requiring dialysis (ARF-D) with a high level of precision. In order to examine the reproducibility of the results on different patient populations, we retrospectively applied the scoring system to 3,508 cardiac surgery patients at the Goettingen University Hospital. We found a qualitative correlation between the score value and ARF-D, but prognostic significance, when judged by the area under the receiver operating characteristic (ROC) curve, was considerably reduced. Also, the incidence of ARF-D in the Goettingen population was remarkably higher than the incidence shown by Thakar for patients with the same score. The correlation between score values and incidence of ARF-D shows that the Thakar score is qualitatively transferable to cardiac surgery patients from other centres. Though the score allows the discrimination between patients with higher or lower risks of ARF-D within the Goettingen collective, it was not suitable to estimate the real incidence of postoperative ARF-D with sufficient precision.

Renal failure is common in critically ill patients and frequently requires continuous renal replacement therapy (CRRT). CRRT is discontinued at regular intervals for routine changes of the disposable equipment or for replacing clogged filter membrane assemblies. The present study was conducted to determine if the necessity to continue CRRT could be predicted during the CRRT-free period. In the period from 2003 to 2006, 605 patients were treated with CRRT in our ICU. A total of 222 patients with 448 CRRT-free intervals had complete data sets and were used for analysis. Of the total CRRT-free periods, 225 served as an evaluation group. Twenty-nine parameters with an assumed influence on kidney function were analyzed with regard to their potential to predict the restoration of kidney function during the CRRT-free interval. Using univariate analysis and logistic regression, a prospective index was developed and validated in the remaining 223 CRRT-free periods to establish its prognostic strength. Only three parameters showed an independent influence on the restoration of kidney function during CRRT-free intervals: the number of previous CRRT cycles (medians in the two outcome groups: 1 vs. 2), the "Sequential Organ Failure Assessment"-score (means in the two outcome groups: 8.3 vs. 9.2) and urinary output after the cessation of CRRT (medians in two outcome groups: 66 ml/h vs. 10 ml/h). The prognostic index, which was calculated from these three variables, showed a satisfactory potential to predict the kidney function during the CRRT-free intervals; Receiver operating characteristic (ROC) analysis revealed an area under the curve of 0.798. Restoration of kidney function during CRRT-free periods can be predicted with an index calculated from three variables. Prospective trials in other hospitals must clarify whether our results are generally transferable to other patient populations.

Postoperative mortality in patients undergoing surgical and/or interventional treatment for acute mesenteric ischemia (AMI) has remained an unsolved problem in recent decades. Here, we investigated clinical predictors of postoperative mortality in a large European cohort of patients undergoing treatment for AMI. In total, 179 patients who underwent surgical and/or interventional treatment for AMI between 2009 and 2021 at our institution were included in this analysis. Associations between postoperative mortality and various clinical variables were assessed using univariate and multivariable binary logistic regression analysis. Most of the patients were diagnosed with arterial ischemia (AI; n = 104), while venous ischemia (VI; n = 21) and non-occlusive mesenteric ischemia (NOMI; n = 54) were present in a subset of patients. Overall inhouse mortality was 55.9% (100/179). Multivariable analyses identified leukocytes (HR = 1.08; p = 0.008), lactate (HR = 1.25; p = 0.01), bilirubin (HR = 2.05; p = 0.045), creatinine (HR = 1.48; p = 0.039), etiology (AI, VI or NOMI; p = 0.038) and portomesenteric vein gas (PMVG; HR = 23.02; p = 0.012) as independent predictors of postoperative mortality. In a subanalysis excluding patients with fatal prognosis at the first surgical exploration (n = 24), leukocytes (HR = 1.09; p = 0.004), lactate (HR = 1.27; p = 0.003), etiology (AI, VI or NOMI; p = 0.006), PMVG (HR = 17.02; p = 0.018) and intraoperative FFP transfusion (HR = 4.4; p = 0.025) were determined as independent predictors of postoperative mortality. Further, the risk of fatal outcome changed disproportionally with increased preoperative lactate values. The clinical outcome of patients with AMI was determined using a combination of pre- and intraoperative clinical and radiological characteristics. Serum lactate appears to be of major clinical importance as the risk of fatal outcome increases significantly with higher lactate values.

Osteopenia is known to be associated with clinical frailty which is linked to inferior outcomes in various clinical scenarios. However, the exact prognostic value of osteopenia in patients undergoing curative intent-surgery for hepatocellular carcinoma (HCC) is not completely understood. This retrospective study was conducted in a cohort of 151 patients who underwent partial hepatectomy for HCC in curative intent at a German university medical center (05/2008–12/2019). Preoperative computed tomography-based segmentation was used to assess osteopenia, and the prognostic impact of pathological changes in bone mineral density (BMD) on perioperative morbidity, mortality, and long-term oncological outcome was analyzed. Five-year overall survival of osteopenic patients was significantly worse compared to those with normal BMD (29% vs. 65%, p = 0.014). In line with this, the probability of disease-free survival at 5 years was significantly worse for patients with osteopenia (21% vs. 64%, p = 0.005). In our multivariable model, osteopenia was confirmed as an independent risk-factor for inferior overall survival (Hazard-ratio 7.743, p = 0.002). Concerning perioperative complications, osteopenic patients performed slightly worse, even though no statistical difference was detected (Clavien-Dindo ≥ 3b; 21% vs. 9%, p = 0.139). The present study confirms osteopenia as an independent risk-factor for inferior survival in patients undergoing partial hepatectomy for HCC in a European cohort. Further studies are warranted to validate these findings.