Soluble Suppression of Tumorigenicity-2 Predicts Mortality and Right Heart Failure in Patients With a Left Ventricular Assist Device.

BACKGROUND: Soluble suppression of tumorigenicity-2 (sST2) predicts mortality in patients with heart failure. The predictive value of sST2 in patients with a left ventricular assist device remains unknown. Therefore, we studied the relationship between sST2 and outcome after left ventricular assist device implantation. METHODS AND RESULTS: sST2 levels of patients with a left ventricular assist device implanted between January 2015 and December 2022 were included in this observational study. The median follow-up was 25 months, during which 1573 postoperative sST2 levels were measured in 199 patients, with a median of 29 ng/mL. Survival of patients with normal and elevated preoperative levels was compared using Kaplan-Meier analysis, which did not differ significantly (P=0.22) between both groups. The relationship between postoperative sST2, survival, and right heart failure was evaluated using a joint model, which showed a significant relationship between the absolute sST2 level and mortality, with a hazard ratio (HR) of 1.20 (95% CI, 1.10-1.130; P<0.01) and an HR of 1.22 (95% CI, 1.07-1.39; P=0.01) for right heart failure, both per 10-unit sST2 increase. The sST2 instantaneous change was not predictive for survival or right heart failure (P=0.99 and P=0.94, respectively). Multivariate joint model analysis showed a significant relationship between sST2 with mortality adjusted for NT-proBNP (N-terminal pro-B-type natriuretic peptide), with an HR of 1.19 (95% CI, 1.00-1.42; P=0.05), whereas the HR of right heart failure was not significant (1.22 [95% CI, 0.94-1.59]; P=0.14), both per 10-unit sST2 increase. CONCLUSIONS: Time-dependent postoperative sST2 predicts all-cause mortality after left ventricular assist device implantation after adjustment for NT-proBNP. Future research is warranted into possible target interventions and the optimal monitoring frequency.

The circadian clock remains intact, but with dampened hormonal output in heart failure.

BACKGROUND: Circadian (24-h) rhythms are important regulators in physiology and disease, but systemic disease may disrupt circadian rhythmicity. Heart failure (HF) is a systemic disease affecting hormonal regulation. We investigate whether HF affects the rhythmic expression of melatonin and cortisol, main endocrine products of the central clock, and cardiac-specific troponin in patients. We corroborate the functionality of the peripheral clock directly in the organs of translational models, inaccessible in human participants. METHODS: We included 46 HF patients (71.7% male, median age of 60 years, NYHA class II (32.6%) or III (67.4%), ischemic cardiomyopathy (43.5%), comorbidities: diabetes 21.7%, atrial fibrillation 30.4%), and 24 matched controls. Blood was collected at seven time-points during a 24-h period (totalling 320 HF and 167 control samples) for melatonin, cortisol, and cardiac troponin T (cTnT) measurements after which circadian rhythms were assessed through cosinor analyses, both on the individual and the group level. Next, we analysed peripheral circadian clock functionality using cosinor analysis in male animal HF models: nocturnal mice and diurnal zebrafish, based on expression of core clock genes in heart, kidneys, and liver, every 4 h during a 24-h period in a light/darkness synchronised environment. FINDINGS: Melatonin and cortisol concentrations followed a physiological 24-h pattern in both patients and controls. For melatonin, acrophase occurred during the night for both groups, with significantly decreased amplitude (median 5.2 vs 8.8, P = 0.0001) and circadian variation ([maximum]/[minimum]) in heart failure patients. For cortisol, mesor showed a significant increase for HF patients (mean 331.9 vs 275.1, P = 0.017) with a difference of 56.8 (95% CI 10.3-103.3) again resulting in a relatively lower variation: median 3.9 vs 6.3 (P = 0.0058). A nocturnal blood pressure dip was absent in 77.8% of HF patients. Clock gene expression profiles (Bmal, Clock, Per, Cry) were similar and with expected phase relations in animal HF models and controls, demonstrating preserved peripheral clock functionality in HF. Furthermore, oscillations in diurnal zebrafish were expectedly in opposite phases to those of nocturnal mice. Concordantly, cTnT concentrations in HF patients revealed significant circadian oscillations. INTERPRETATION: Central clock output is dampened in HF patients while the molecular peripheral clock, as confirmed in animal models, remains intact. This emphasises the importance of taking timing into account in research and therapy for HF, setting the stage for another dimension of diagnostic, prognostic and therapeutic approaches. FUNDING: Hartstichting.

Analysis of C-reactive protein from finger stick dried blood spot to predict high risk of cardiovascular disease.

C-reactive protein (CRP) is an acute-phase protein involved in inflammation. Furthermore, CRP is an important biomarker used in diagnostics to predict risk of cardiovascular disease (CVD) in addition to monitoring bacterial and viral infections. To measure plasma CRP, venipuncture is still necessitated and has to be performed by trained phlebotomists. As a solution, dried blood spots (DBS) are used for minimally invasive at-home sampling of blood and can be send to diagnostic laboratories by regular mail. In this study, we included 53 patients that presented to the outpatient clinic of the University Medical Center Utrecht. Capillary finger stick was used to spot blood on a filter paper card and allowed to dry. After extraction of DBS, CRP was analyzed on an automated high-throughput chemistry analyzer. Additional validation steps regarding stability, effect of hematocrit, precision, and limits of blank and quantitation were conducted according to corresponding Clinical and Laboratory Standards Institute standards. An excellent regression analysis of R2 (95% confidence interval) = 0.986 (0.982-0.989) was found. This enabled correct classification for high CVD risk of all 25 cases with sensitivity (95% CI) of 1.00 (1.00-1.00) and specificity (95% CI) of 0.96 (0.89-1.03) and correct diagnosis of inflammation of 12/13 cases with sensitivity (95% CI) of 0.92 (0.77-1.07) and specificity (95% CI) of 1.00 (1.00-1.00). Furthermore, CRP was found to be stable for 31 days and observed hematocrit variation amongst patients was clinically acceptable. CRP from DBS can be accurately measured on an automated high-throughput chemistry analyzer and used to diagnose inflammation and classify high CVD risk. This method enables individuals to engage in at-home sampling of blood on DBS for (tele)diagnostics, screening programs, patient follow-up, and medication management.

Evaluation and management of leukolysis-mediated pseudohyperkalemia in paediatric leukemic samples.

INTRODUCTION: Leukolysis-related pseudohyperkalemia due to preanalytical procedures may lead to erroneous (or absence of) treatment based on an invalid lab test result. We aimed to obtain a leukocyte threshold above which leukolysis-related pseudohyperkalemia becomes clinical relevant. Secondly, temporal dynamics of treatment-induced leukocyte decrease were studied to allow tailored implementation of laboratory information system (LIS) decision rules based on the leukocyte threshold to avoid leukolysis-related pseudohyperkalemia. MATERIALS AND METHODS: Potassium results of AU5811 routine chemistry (Beckman Coulter, Brea, California, USA) and iStat point of care (POC) (Abbott Diagnostics, Chicago, Illinois, USA) analysers were compared, the latter method being insensitive to leukolysis caused by pre-analytical procedures. Potassium results were combined with leukocyte counts obtained using a Cell-Dyn Sapphire haematology analyser (Abbott Diagnostics, Santa Clara, California, USA), resulting in 132 unique data triplets. Regression analysis was performed to establish a leukocyte threshold. The Reference Change Value (√2 x Z x √(CVa 2 + CVi 2)) was used to calculate maximum allowable difference between routine analyser and POC potassium results (deltamax + 0.58 mmol/L). Temporal analysis on the treatment-induced leukocyte decrease was performed by plotting leukocyte counts in time for all patients above the threshold leukocyte count (N = 41). RESULTS: Established leukocyte threshold was 63 x109/L. Temporal analysis showed leukocyte counts below the threshold within 8 days of treatment for all patients. CONCLUSIONS: Based on performed analyses we were able to implement LIS decision rules to reduce pseudohyperkalemia due to preanalytical procedures. This implementation can contribute to a reduction in erroneous (or absence of) treatments in the clinic.

Prognostic biomarker soluble ST2 exhibits diurnal variation in chronic heart failure patients.

AIM: Soluble suppression of tumorigenicity-2 (sST2) is a strong prognostic biomarker in heart failure. The emerging understanding of circadian biology in cardiovascular disease may lead to novel applications in prognosis and diagnosis and may provide insight into mechanistic aspects of the disease-biomarker interaction. So far, it is unknown whether sST2 exhibits a diurnal rhythm. Repeated measurements of sST2 may aid in clinical decision making. The goal of this study was to investigate whether sST2 exhibits diurnal variation in patients with heart failure with reduced ejection fraction (HFrEF) and in control subjects, thereby enhancing its diagnostic and prognostic values. METHODS AND RESULTS: The study comprised 32 subjects: 16 HFrEF patients and 16 controls. Blood was collected at seven subsequent time points during a 24 h time period. sST2, N-terminal pro-B-type natriuretic peptide (NT-proBNP), melatonin, and cortisol were measured from serum. Peak values of sST2 clustered at daytime (modal value: 5 p.m.) in 87.6% of all subjects (81.3% of patients, P = 0.021; 93.8% of controls, P = 0.001), and minimum concentrations at night-time (modal value: 5 a.m.) in 84.4% (87.5% of patients, P = 0.004 81.3% of controls, P = 0.021). A cosinor analysis of mean normalized sST2 values revealed significant cosine shaped 24 h oscillations of patients (P = 0.026) and controls (P = 0.037). NT-proBNP in contrast did not show a diurnal rhythm, while melatonin and cortisol patterns were intact in all subjects. CONCLUSIONS: sST2 exhibits a diurnal rhythm with lower values in the morning than in the late afternoon. This new insight could lead to refinement of its diagnostic and prognostic values through specified and consistent sampling times with repeated measurements. For example, by measuring sST2 during the afternoon, when levels are at their highest, false negatives on prognosis prediction could be avoided.

Diagnostic Accuracy of Procalcitonin and C-reactive Protein Is Insufficient to Predict Proven Infection: A Retrospective Cohort Study in Critically Ill Patients Fulfilling the Sepsis-3 Criteria.

BACKGROUND: New Sepsis-3 definitions facilitate early recognition of patients with sepsis. In this study we investigated whether a single initial determination of procalcitonin (PCT) or C-reactive protein (CRP) in plasma can predict proven sepsis in Sepsis-3 criteria-positive critically ill patients. We also investigated whether a decline in serial PCT or CRP can predict outcome in 28-day mortality. METHODS: Patients, ≥18 years of age, at the intensive care unit with a suspected infection, a Sequential Organ Failure Assessment (SOFA) score of ≥2 points, and an index test PCT and CRP at admission were selected from a prospectively collected cohort. PCT and CRP were studied retrospectively with the Mann-Whitney U-test and ROC analysis. RESULTS: In total, 157 patients were selected; 63 of the 157 had proven sepsis, and sepsis could not be detected in 94 of the 157. Neither a single PCT nor CRP at admission was able to discriminate proven sepsis from nonproven sepsis (PCT, 1.8 µg/L and 1.5 µg/L, respectively, P = 0.25; CRP, 198 mg/L and 186 mg/L, respectively, P = 0.53). Area under the curve for both PCT and CRP for detecting proven sepsis was low (0.55 and 0.53). Furthermore, neither a decline from baseline to day 5 PCT nor CRP could predict 28-day mortality (PCT, 50% vs 46%, P = 0.83; CRP, 30% vs 40%, P = 0.51). CONCLUSION: PCT and CRP at admission were not able to discern patients with proven sepsis in Sepsis-3 criteria-positive critically ill patients. A decline of PCT and CRP in 5 days was not able to predict 28-day mortality.

Osteoprotegerin is Higher in Sepsis Than in Noninfectious SIRS and Predicts 30-Day Mortality of SIRS Patients in the Intensive Care.

BACKGROUND: Systemic inflammatory response syndrome (SIRS) is a complex disease involving multiple pathways and organs. Biomarkers reflecting these pathways and organ function could correlate with the severity of the disease. Osteoprotegerin (OPG), mainly known for its role in bone metabolism, is also involved in the immune and vascular system and is therefore an interesting biomarker to study in SIRS patients. In this prospective observational study, we investigated the correlation of plasma OPG concentrations, sepsis, and 30-day mortality of SIRS patients in the intensive care unit (ICU). METHODS: This observational, single-center, cohort study included 313 consecutive patients admitted to the ICU, with an anticipated stay of more than 48 h and SIRS on admission. Data from included patients were collected daily until discharge or death for a maximum of 10 days. Thirty-day mortality was retrospectively assessed. OPG concentrations were measured in the first 48 h after admission. The relation of OPG with no sepsis, sepsis, and septic shock was assessed with the Kruskal-Wallis test and the Mann-Whitney U-test. Cox proportional hazards regression was used to study OPG concentrations and 30-day mortality. RESULTS: OPG concentrations were higher in patients with sepsis and septic shock than in patients without sepsis. Furthermore, patients with OPG concentrations in the highest tertile at admission in the ICU have an increased risk of mortality within 30 days when compared to patients with OPG concentrations in the lowest and middle tertiles, independent of acute physiologic and chronic health evaluation (APACHE) and sequential organ failure assessment (SOFA) scores. CONCLUSIONS: We show that OPG is a biomarker that correlates with sepsis and predicts mortality of SIRS patients in the ICU.

Low-calcium diet in mice leads to reduced gut colonization by Enterococcus faecium.

The aim of this study was to determine whether dietary intervention influenced luminal Ca2+ levels and Enterococcus faecium gut colonization in mice. For this purpose, mice fed semi-synthetic food AIN93 were compared to mice fed AIN93-low calcium (LC). Administration of AIN93-LC resulted in lower luminal Ca2+ levels independent of the presence of E. faecium. Furthermore, E. faecium gut colonization was reduced in mice fed AIN93-LC based on culture, and which was in concordance with a reduction of Enterococcaceae in microbiota analysis. In conclusion, diet intervention might be a strategy for controlling gut colonization of E. faecium, an important opportunistic nosocomial pathogen.

Improving home haemodialysis: Stability evaluation of routine clinical chemistry analytes in blood samples of haemodialysis patients.

INTRODUCTION: A growing number of dialysis patients is treated with home haemodialysis. Our current pre-analytical protocols require patients to centrifuge the blood sample and transfer the plasma into a new tube at home. This procedure is prone to errors and precludes accurate bicarbonate measurement, required for determining dialysate bicarbonate concentration and maintaining acid-base status. We therefore evaluated whether cooled overnight storage of gel separated plasma is an acceptable alternative. MATERIALS AND METHODS: Venous blood of 34 haemodialysis patients was collected in 2 lithium heparin blood collection tubes with gel separator (LH PSTTM II, REF 367374; Becton Dickinson, New Jersey, USA). One tube was analysed directly for measurement of bicarbonate, potassium, calcium, phosphate, glucose, urea, lactate, aspartate aminotransferase (AST), and lactate dehydrogenase (LD); whereas the other was centrifuged and stored unopened at 4 °C and analysed 24 h later. To measure analyte stability after 24 h of storage, the mean difference was calculated and compared to the total allowable error (TEa) which was used as acceptance limit. RESULTS: Potassium (Z = - 4.28, P < 0.001), phosphate (Z = - 3.26, P = 0.001), lactate (Z = - 5.11, P < 0.001) and AST (Z = - 2.71, P = 0.007) concentrations were higher, whereas glucose (Z = 4.00, P < 0.001) and LD (Z = 3.13, P = 0.002) showed a reduction. All mean differences were smaller than the TEa and thus not clinically relevant. Bicarbonate (Z = 0.69, P = 0.491), calcium (Z = - 0.23, P = 0.815) and urea (Z = 0.81, P =0.415) concentrations were stable. CONCLUSIONS: Our less complex, user-friendly pre-analytical procedure resulted in at least 24 h stability of analytes relevant for monitoring haemodialysis, including bicarbonate. This allows shipment and analysis the next day.

Falsely decreased ferritin concentrations in two patients with haemophagocytic lymphohistiocytosis: A case report.

The high-dose hook effect, or prozone effect, can lead to negative or falsely lowered plasma ferritin results. Here, cases of a 16-year-old boy and a 70-year-old woman with haemophagocytic lymphohystiocytosis with extremely high concentrations of plasma ferritin (387,000 µg/L and 138,000 µg/L, respectively) are presented. In both cases, falsely lowered ferritin results were reported without any analyser flag. This article emphasizes the importance of recognition of the high-dose hook effect, since a watertight solution is lacking.

Myeloperoxidase can differentiate between sepsis and non-infectious SIRS and predicts mortality in intensive care patients with SIRS.

BACKGROUND: Systemic inflammatory response syndrome (SIRS) is a clinical syndrome following inflammation. Clinically, it is difficult to distinguish SIRS following an infection, i.e., sepsis, from non-infectious SIRS. Myeloperoxidase is a hemeprotein stored in the neutrophil azurophilic granules and is one of the main pillars of neutrophil attack. Therefore, we hypothesized that myeloperoxidase can differentiate between sepsis and non-infectious SIRS in patients with systemic inflammatory response syndrome in the intensive care unit (ICU). METHODS: An observational single-center cohort study was conducted measuring myeloperoxidase in patients with SIRS in the first 48 h after admission. The outcomes were established using predefined definitions. Thirty-day mortality was retrospectively assessed. RESULTS: We found significantly higher levels of myeloperoxidase in patients with sepsis and septic shock compared to patients without sepsis (60 ng/ml versus 43 ng/ml, P = 0.002). Myeloperoxidase levels were related to 30-day mortality (P = 0.032), and high MPO levels on top of a high APACHE IV score further increased mortality risk. CONCLUSIONS: We show that myeloperoxidase is a potentially novel biomarker for sepsis in the ICU. Myeloperoxidase could eventually help in diagnosing sepsis and predicting mortality. However, more research is necessary to confirm our results.

Soluble P-selectin as a Biomarker for Infection and Survival in Patients With a Systemic Inflammatory Response Syndrome on the Intensive Care Unit.

AIMS: This study investigated the ability of soluble platelet selectin (sP-selectin) to identify infection and predict 30-day mortality in patients with a systemic inflammatory response syndrome (SIRS) on the intensive care unit. METHODS: Soluble platelet selectin levels were measured daily in the first 48 hours in patients presenting with SIRS. The outcome, proven infection, was established using predefined definitions. The 30-day mortality was retrospectively assessed. RESULTS: In a total of 313 patients with SIRS, sP-selectin levels were measured. Of these, 114 patients had proven infection on admission or developing during their intensive care unit (ICU) stay. Patients with proven infection had moderately higher levels of sP-selectin (147 ng/mL; interquartile range [IQR], 93.4-203 ng/mL) compared with noninfected patients (143.8 ng/mL; IQR, 89.6-194.7 ng/mL). This difference was not statistically significant (P = .072). However, in patients who were not admitted for infection (n = 235), sP-selectin levels were significantly related to the subsequent development of infection (P = .013). Soluble platelet selectin levels were particularly high in patients with abdominal sepsis and skin infections. Higher sP-selectin levels were associated with higher mortality (although not statistically significant, P = .08). CONCLUSIONS: This study shows that in patients with SIRS not admitted for infection, sP-selectin levels are significantly related to the subsequent development of infection. Furthermore, patients with higher sP-selectin levels in the first 2 days of admission had higher 30-day mortality, although this association is not statistically significant. Therefore, we conclude that sP-selectin is a potential future biomarker for both mortality and infection in patients with SIRS, but more research is needed to confirm its prognostic role.

Baseline thrombospondin-1 concentrations are not associated with mortality in septic patients: a single-center cohort study on the intensive care unit.

BACKGROUND: The initial phase of sepsis is characterized by hyperinflammation. Levels of thrombospondin-1 (TSP-1) rise rapidly during acute inflammation. The purpose of this clinical study was to study the association between plasma TSP-1 levels and mortality in patients with sepsis on the intensive care unit. METHODS: Critically ill adult patients with sepsis, severe sepsis, or septic shock were included. They were further divided into tertiles based on their baseline plasma TSP-1 concentrations. Primary outcome measure was 28-day mortality. Furthermore, associations with severity of sepsis and platelet counts were studied. RESULTS: Two hundred thirty-five patients were included. Median plasma TSP-1 concentrations of the tertiles were 194, 463 and 874 ng/mL, respectively. There were no baseline differences. Mortality rates (26.6, 16.7, and 16.7%, p = 0.20) and cumulative survival curves (p = 0.22) were not statistically different between the tertiles. There was no association of baseline TSP-1 with severity of sepsis (p = 0.08). TSP-1 and platelet counts were positively correlated (159, 198, and 295 × 109/L, p = 0.04). CONCLUSIONS: Baseline plasma levels of TSP-1 were not associated with mortality and severity of sepsis in mixed population of septic ICU patients. Further research is needed to clarify the expression of TSP-1 and to unravel the potential prognostic value of this biomarker in human sepsis.

Implementation and application of moving average as continuous analytical quality control instrument demonstrated for 24 routine chemistry assays.

BACKGROUND: General application of a moving average (MA) as continuous analytical quality control (QC) for routine chemistry assays has failed due to lack of a simple method that allows optimization of MAs. A new method was applied to optimize the MA for routine chemistry and was evaluated in daily practice as continuous analytical QC instrument. METHODS: MA procedures were optimized using an MA bias detection simulation procedure. Optimization was graphically supported by bias detection curves. Next, all optimal MA procedures that contributed to the quality assurance were run for 100 consecutive days and MA alarms generated during working hours were investigated. RESULTS: Optimized MA procedures were applied for 24 chemistry assays. During this evaluation, 303,871 MA values and 76 MA alarms were generated. Of all alarms, 54 (71%) were generated during office hours. Of these, 41 were further investigated and were caused by ion selective electrode (ISE) failure (1), calibration failure not detected by QC due to improper QC settings (1), possible bias (significant difference with the other analyzer) (10), non-human materials analyzed (2), extreme result(s) of a single patient (2), pre-analytical error (1), no cause identified (20), and no conclusion possible (4). CONCLUSIONS: MA was implemented in daily practice as a continuous QC instrument for 24 routine chemistry assays. In our setup when an MA alarm required follow-up, a manageable number of MA alarms was generated that resulted in valuable MA alarms. For the management of MA alarms, several applications/requirements in the MA management software will simplify the use of MA procedures.

Optimization and validation of moving average quality control procedures using bias detection curves and moving average validation charts.

BACKGROUND: To date, no practical tools are available to obtain optimal settings for moving average (MA) as a continuous analytical quality control instrument. Also, there is no knowledge of the true bias detection properties of applied MA. We describe the use of bias detection curves for MA optimization and MA validation charts for validation of MA. METHODS: MA optimization was performed on a data set of previously obtained consecutive assay results. Bias introduction and MA bias detection were simulated for multiple MA procedures (combination of truncation limits, calculation algorithms and control limits) and performed for various biases. Bias detection curves were generated by plotting the median number of test results needed for bias detection against the simulated introduced bias. In MA validation charts the minimum, median, and maximum numbers of assay results required for MA bias detection are shown for various bias. Their use was demonstrated for sodium, potassium, and albumin. RESULTS: Bias detection curves allowed optimization of MA settings by graphical comparison of bias detection properties of multiple MA. The optimal MA was selected based on the bias detection characteristics obtained. MA validation charts were generated for selected optimal MA and provided insight into the range of results required for MA bias detection. CONCLUSIONS: Bias detection curves and MA validation charts are useful tools for optimization and validation of MA procedures.