Traditional cutoff values of serum creatinine considered to define postoperative acute renal failure have been challenged recently. In a previous investigation we demonstrated that minimal changes in serum creatinine concentration were associated with a substantial decrease in survival after cardiac surgery. In this investigation, we assessed the impact of minimal absolute increases in serum creatinine in a second institution, and we analyzed whether relative changes, as in the RIFLE classification and, partially, in Acute Kidney Injury Network (AKIN) classification, confer a different prognostic potential. Prospective analysis. University hospital. All consecutive patients undergoing cardiac surgery in the University Hospital of Zurich (Center USZ) over a 46-month period. Patients were prospectively documented. We analyzed maximal changes in serum creatinine in the first 48 hrs postoperatively (ΔCrea) regarding death within 30 days. Results were compared with those of the University Hospital Vienna (Center AKH). Moreover, the prognostic potential of ΔCrea within 48 hrs vs. serum creatinine elements according to RIFLE and AKIN classifications was assessed. A total of 3,123 patients were evaluated from USZ. The majority of patients had decreased postoperative serum creatinine values (negative ΔCrea) and the lowest mortality (1.8%). Minimal increases, [0, 0.5) mg·dL−1, were associated with a more than doubled mortality in both centers (5%/6%). Mortality, according to RIFLE and AKIN classifications for both populations combined, was as follows: 7,023 (3.6%), 160 (29%), 43 (19%), and 15 (33%) for RIFLE Normal, Risk, Injury, and Failure; 6,644 (2.8), 463 (16.4), 3 (66.7), and 131 (1.8) for AKIN stage 0, 1, 2, and 3. Measuring repeat serum creatinine concentrations within 48 hrs and determining ΔCrea were the most effective discrimination method to find patients at risk for adverse postoperative outcome after cardiac surgery, better than application of this sole criterion to the RIFLE (least discriminatory) or the AKIN classification.

Hyponatremia is the most common electrolyte disorder in hospitalized patients and is known to be associated with increased mortality. The administration of antegrade single-shot, up to two liters, histidine-tryptophane-ketoglutarate (HTK) solution for adequate electromechanical cardiac arrest and myocardial preservation during minimally invasive aortic valve replacement (MIAVR) is a standard procedure. We aimed to determine the impact of HTK infusion on electrolyte and acid–base balance. In this retrospective analysis we reviewed data on patient characteristics, type of surgery, arterial blood gas analysis during surgery and intra-/postoperative laboratory results of patients receiving surgery for MIAVR at a large tertiary care university hospital. A total of 25 patients were included in the study. All patients were normonatremic at start of surgery. All patients developed hyponatremia after administration of HTK solution with a significant drop of serum sodium of 15 mmol/L (p < 0.01). Measured osmolality did not change during all times of surgery compared to start of surgery (p = 0.28 – p = 0.79), indicating isotonic hyponatremia. After administration of HTK solution pH fell significantly due to development of metabolic acidosis. Acute hyponatremia during cardioplegia with HTK solution is isotonic and should probably not be corrected without presence of hypotonicity as confirmed by measurement of serum osmolality.

Interleukin-6 (IL-6) can cause pro- and anti-inflammatory effects via different signaling pathways. This prospective study investigated the perioperative kinetics of IL-6, soluble IL-6 receptor (sIL-6R), and soluble glycoprotein 130 (sgp130) in elective patients undergoing cardiopulmonary bypass (CPB). IL-6, sIL-6R, and sgp130 were measured simultaneously and consecutively at 19 timepoints until the 10th postoperative day (POD). The proportion of pro- and anti-inflammatory pathways were determined by calculating sIL-6R/IL-6 and sIL-6R/sgp130 ratios. We analyzed 93 patients. IL-6 increased during surgery with reaching a plateau two hours after CPB and peaking on POD 1 (188.5 pg mL⁻¹ (IQR, 126.6; 309.2)). sIL-6R decreased at the beginning of the surgical procedure, reaching a nadir level on POD 2 (26,311 pg mL⁻¹ (IQR, 22,222; 33,606)). sgp130 dropped immediately after CPB initiation (0.13 ng mL⁻¹ (IQR, 0.12; 0.15)), followed by a continuous recovery until POD10. The sIL-6R/IL-6 ratio decreased substantially at the beginning of the procedure, reaching a nadir on POD 1 (149.7 (IQR, 82.4; 237.4)), while the sIL-6R/sgp130 ratio increased simultaneously until 6 h post CPB (0.219 (IQR 0.18; 0.27)). In conclusion, IL-6 exhibited high inter-individual variability reflecting an inhomogeneous inflammatory response. Pro-inflammatory effects and overwhelming inflammation were rare and predominantly anti-inflammatory effects were found.

Background: The phase angle (PhA) can be used for prognostic assessments in critically ill patients. This study describes the perioperative course of PhA and associated risk indicators in a cohort of elective cardiac surgical patients. Methods: The PhA was measured in 168 patients once daily until postoperative day (POD) seven. Patients were split into two groups depending on their median preoperative PhA and analyzed for several clinical outcomes; logistic regression models were used. Results: The PhA decreased from preoperative (6.1° ± 1.9°) to a nadir on POD 2 (3.5° ± 2.5°, mean difference −2.6° (95% CI, −3.0°; −2.1°; p < 0.0001)). Patients with lower preoperative PhA were older (71.0 ± 9.1 vs. 60.9 ± 12.0 years; p < 0.0001) and frailer (3.1 ± 1.3 vs. 2.3 ± 1.1; p < 0.0001), needed more fluids (8388 ± 3168 vs. 7417 ± 2459 mL, p = 0.0287), and stayed longer in the ICU (3.7 ± 4.5 vs. 2.6 ± 3.8 days, p = 0.0182). Preoperative PhA was independently influenced by frailty (OR 0.77; 95% CI 0.61; 0.98; p = 0.0344) and cardiac function (OR 1.85; 95%CI 1.07; 3.19; p = 0.028), whereas the postoperative PhA decline was independently influenced by higher fluid balances (OR 0.86; 95% CI 0.75; 0.99; p = 0.0371) and longer cardiopulmonary bypass times (OR 0.99; 95% CI 0.98; 0.99; p = 0.0344). Conclusion: Perioperative PhA measurement is an easy-to-use bedside method that may critically influence risk evaluation for the outcome of cardiac surgery patients.

BACKGROUND Aortic valve replacement is one of the most common cardiac surgical procedures, especially in elderly patients. Whether or not there is a net life gain over a long period of time is a matter for debate. OBJECTIVE To compare survival of patients with that of the age, sex, and follow-up year-matched normal population (relative survival). DESIGN Single-centre, prospectively collected data. SETTING Tertiary care centre, Vienna, Austria. PATIENTS We enrolled 1848 patients undergoing elective aortic valve replacement between 1997 and the end of 2008. INTERVENTIONS None. MAIN OUTCOME MEASUREMENT Relative survival at the end of 2011 as determined by relative Cox regression analysis. RESULTS Sixty-nine patients (3.7%) died within the first 30 days. Another 70 patients (3.8%) died within the first year and 429 (23.2%) died during the remaining follow-up period. The longest follow-up period was 14 years (median, 5.8; interquartile range, 3.2 to 8.9). Medical risk indicators for relative survival were diabetes mellitus [hazard ratio 1.69, 95% confidence interval, CI 1.37 to 2.07, P <0.001], pulmonary disease (hazard ratio 1.45, 95% CI 1.16 to 1.81, P = 0.001), history of atrial fibrillation (hazard ratio 1.35, 95% CI 1.10 to 1.66, P = .005) and angiotensin-converting enzyme inhibitor medication (hazard ratio 1.21, 95% CI 1.02 to 1.44, P = 0.031). Perioperative risk indicators were urgent surgery (hazard ratio 1.40, 95% CI 1.00 to 1.94, P = 0.047), resternotomy at 48 h or less (hazard ratio 1.87, 95% CI 1.29 to 2.70, P = 0.001), resternotomy at more than 48 h (hazard ratio 1.80, 95% CI 1.32 to 2.45, P <0.001), blood transfusion (hazard ratio 1.06, 95% CI 1.01 to 1.12, P = 0.018) and renal replacement therapy (hazard ratio 2.02, 95% CI 1.41 to 2.90, P <0.001). Relative survival was highest in the oldest age quartile (76 to 94 years) and lowest in the youngest (19 to 58 years) (hazard ratio 0.27, 95% CI 0.21 to 0.36; P <0.001). CONCLUSION Patients who survived the first year after aortic valve replacement had a similar chance of survival as the matched normal population. Relative survival benefit was higher in the oldest age quartile.

An acute kidney injury (AKI) is the most common complication following cardiac surgery, and can lead to the initiation of continuous renal replacement therapy (CRRT). However, there is still insufficient evidence for when patients should be liberated from CRRT. Proenkephalin A 119–159 (PENK) is a novel biomarker that reflects kidney function independently of other factors. This study investigated whether PENK could guide successful liberation from CRRT. Therefore, we performed a prospective, observational, single-center study at the Medical University of Vienna between July 2022 and May 2023, which included adult patients who underwent cardiac surgery for a cardiopulmonary bypass; patients on preoperative RRT were excluded. The PENK levels were measured at the time of AKI diagnosis and at the initiation of and liberation from CRRT, and were subsequently compared to determine whether the patients were successfully liberated from CRRT. We screened 61 patients with postoperative AKI; 20 patients experienced a progression of AKI requiring CRRT. The patients who were successfully liberated from CRRT had mean PENK levels of 113 ± 95.4 pmol/L, while the patients who were unsuccessfully liberated from CRRT had mean PENK levels of 290 ± 175 pmol/L (p = 0.018). For the prediction of the successful liberation from CRRT, we found an area under the curve of 0.798 (95% CI, 0.599–0.997) with an optimal threshold value of 126.7 pmol/L for PENK (Youden Index = 0.53, 95% CI, 0.10–0.76) at the time of CRRT liberation (sensitivity = 0.64, specificity = 0.89). In conclusion, PENK is a novel biomarker that has the potential to predict the successful liberation from CRRT for patients with AKI after cardiac surgery.