Modifiable factors associated with postoperative atrial fibrillation in older patients with hip fracture in an orthogeriatric care pathway: a nested case-control study.

BACKGROUND: Few data are available regarding post-operative atrial fibrillation (POAF) in non-cardiothoracic surgery, particularly orthopedic surgery. Hence, given the frequent incidence of POAF after surgery and its marked impact, we need to identify modifiable factors associated with POAF after hip fracture surgery in older patients. METHODS: We conducted a nested case-control study in the unit for perioperative geriatric care of an academic hospital in Paris from July 1, 2009 to December 31, 2019, enrolling all consecutive patients aged ≥ 70 years with hip fracture surgery and no history of permanent AF before admission (retrospective analysis of prospectively collected data). Patients with and without POAF were matched 1:5 on 5 baseline characteristics (age, hypertension, diabetes, coronary artery disease, cardiac failure). RESULTS: Of the 757 patients included, 384 were matched, and 64 had POAF. The incidence of POAF was 8.5%. The mean age was 86 ± 6 years, 298 (78%) patients were female, and the median Charlson Comorbidity Index was 6 (interquartile range 4-8). The median time from surgery to the occurrence of POAF was 2 days (1-4). On multivariable conditional logistic regression analysis (matched cohort), the modifiable factors present at admission associated with POAF were time to surgery > 48 h (odds ratio [OR] = 1.66, 95% confidence interval [1.01-2.81]) and > 2 units of packed red blood cells (OR = 3.94, [1.50-10.03]). CONCLUSIONS: This study provides new information about POAF in older patients with hip fracture surgery, a surgical emergency whose complexity requires multidisciplinary care.

How useful is an oral calcium load test for diagnosing recurrent calcium stone formers?

Hypercalciuria is the main risk factor for recurrent calcium urolithiasis. The goal of our study is to determinate how useful an oral calcium load test is for stone formers to classify different forms of hypercalciuria in pathogenetic categories defined as renal or absorptive according to the current knowledge. Between June 2013 and February 2016, a prospective study was carried out on 117 documented recurrent hypercalciuric stone formers undergoing an oral calcium load test modified from the original description by Pak. After 2 days of calcium-restricted diet, urine and blood were analyzed at baseline and 120 min after receiving orally 1 g of calcium. Total and ionized calcium, parathyroid hormone from serum and urine calcium and creatinine were assessed in order to divide patients in three groups as previously described: resorptive, absorptive, and renal hypercalciuria. This allowed the identification of 19, 39, 34 and 33 patients with normocalcemic primary hyperparathyroidism (NPHPT), renal hypercalciuria aka renal calcium leak (RCL), absorptive hypercalciuria (AH) and unidentified cause, respectively. Patients with NPHPT (who required parathyroidectomy) experienced a lower PTH decrease (41.41 ± 12.82 vs. 54.06 ± 13.84% p < 0.01), higher beta-crosslaps, as well as lower TmP/GFR and distal third radius bone mineral density. RCL resulted in increased fasting urine calcium-to-creatinine ratio (Uca/Cr), i.e., > 0.37 mmol/mmol), without hyperparathyroidism. AH was diagnosed by the presence of ΔUCa/Cr > 0.60 mmol/mmol between baseline and 120 min without any other anomaly. For all remaining patients, results were inconclusive due to the lack of sufficient increase in serum calcium or because the cause of lithogenesis could not be clearly identified. The oral calcium load test is useful in nearly 80% of patients by identifying the different forms of hypercalciuria causing urolithiasis and by guiding treatment, including parathyroid surgery.

How the diagnosis and the management of genetic renal phosphate leak impact the life of kidney stone formers?

Genetic renal phosphate leak is one of the rare disorders in recurrent stone formers with absorptive hypercalciuria. Diagnosis and appropriate management may change the life of patients. To provide answers on how and when to make the diagnosis of genetic renal phosphate leak and how medical management prevents the recurrences and changes patients' life, we conducted a retrospective study including nine patients with recurrent nephrolithiasis and a confirmed genetic mutation of a phosphate transporter between 2008 and 2019 in our multidisciplinary center at the Pitié Salpetriere Hospital, Paris, France. We compared the number and the annual rate of urological intervention before and after the diagnosis and management using the Wilcoxon test. A qualitative survey was done to evaluate the quality of life of patients. A total of 9 patients were included in this study. Patient baseline characteristics and elements supporting the diagnosis are described. We showed an effective decrease in urological intervention number (p = 0.0078) and annual rate (p = 0.0117) after the diagnosis and the appropriate management, and an improvement in the patients' quality of life. The diagnosis and the appropriate management of genetic renal phosphate leak disorder improve the quality of life by preventing stone recurrence and decreasing the number of surgical intervention.

Implication of folate deficiency in CYP2U1 loss of function.

Hereditary spastic paraplegias are heterogeneous neurodegenerative disorders. Understanding of their pathogenic mechanisms remains sparse, and therapeutic options are lacking. We characterized a mouse model lacking the Cyp2u1 gene, loss of which is known to be involved in a complex form of these diseases in humans. We showed that this model partially recapitulated the clinical and biochemical phenotypes of patients. Using electron microscopy, lipidomic, and proteomic studies, we identified vitamin B2 as a substrate of the CYP2U1 enzyme, as well as coenzyme Q, neopterin, and IFN-α levels as putative biomarkers in mice and fluids obtained from the largest series of CYP2U1-mutated patients reported so far. We also confirmed brain calcifications as a potential biomarker in patients. Our results suggest that CYP2U1 deficiency disrupts mitochondrial function and impacts proper neurodevelopment, which could be prevented by folate supplementation in our mouse model, followed by a neurodegenerative process altering multiple neuronal and extraneuronal tissues.

Covichem: A biochemical severity risk score of COVID-19 upon hospital admission.

Clinical and laboratory predictors of COVID-19 severity are now well described and combined to propose mortality or severity scores. However, they all necessitate saturable equipment such as scanners, or procedures difficult to implement such as blood gas measures. To provide an easy and fast COVID-19 severity risk score upon hospital admission, and keeping in mind the above limits, we sought for a scoring system needing limited invasive data such as a simple blood test and co-morbidity assessment by anamnesis. A retrospective study of 303 patients (203 from Bordeaux University hospital and an external independent cohort of 100 patients from Paris Pitié-Salpêtrière hospital) collected clinical and biochemical parameters at admission. Using stepwise model selection by Akaike Information Criterion (AIC), we built the severity score Covichem. Among 26 tested variables, 7: obesity, cardiovascular conditions, plasma sodium, albumin, ferritin, LDH and CK were the independent predictors of severity used in Covichem (accuracy 0.87, AUROC 0.91). Accuracy was 0.92 in the external validation cohort (89% sensitivity and 95% specificity). Covichem score could be useful as a rapid, costless and easy to implement severity assessment tool during acute COVID-19 pandemic waves.

Transportation and handling of blood samples prior to ammonia measurement in the real life of a large university hospital.

BACKGROUND: Hyperammonemia is neurotoxic and as such can be a medical emergency. Preanalytical factors greatly influence the blood ammonia concentration results. AIMS AND METHODS: Ammonia concentrations measured in the real life setting of a large hospital after pneumatic transport of blood samples and various time periods before centrifugation were compared to those based on the indications of the reagent manufacturer. In the same routine context, the effects of waiting times of centrifuged samples or after plasma storage at -20 °C and -80 °C were determined. RESULTS: Despite the pneumatic transport, the lead times for sample arrival to the lab were even longer than those recommended for their complete handling until ammonia assay. Ammonia concentration results were not affected by the pneumatic transport of blood samples and by waiting times up to a maximum of 1.75 h before their centrifugation and 1 h after centrifugation. Ammonia stability was superior when plasma was stored at -80 °C. CONCLUSION: Pneumatic transport and sample handling in the routine practice of our lab do not affect ammonia concentration results provided that waiting times are limited to 1.75 h before and 1 h after centrifugation and samples are kept cold. Otherwise, it is better to freeze plasma at -80 °C.

Significance of NT-proBNP and High-sensitivity Troponin in Friedreich Ataxia.

BACKGROUND: Friedreich's ataxia (FA) is a rare autosomal recessive mitochondrial disease resulting of a triplet repeat expansion guanine-adenine-adenine (GAA) in the frataxin (FXN) gene, exhibiting progressive cerebellar ataxia, diabetes and cardiomyopathy. We aimed to determine the relationship between cardiac biomarkers, serum N-terminal pro-brain natriuretic peptide (NT-proBNP), and serum cardiac high-sensitivity troponin (hsTnT) concentrations, and the extent of genetic abnormality and cardiac parameters. METHODS: Between 2013 and 2015, 85 consecutive genetically confirmed FA adult patients were prospectively evaluated by measuring plasma hsTnT and NT-proBNP concentrations, electrocardiogram, and echocardiography. RESULTS: The 85 FA patients (49% women) with a mean age of 39 ± 12 years, a mean disease onset of 17 ± 11 years had a mean SARA (Scale for the Assessment and Rating of Ataxia) score of 26 ± 10. The median hsTnT concentration was 10 ng/L (3 to 85 ng/L) and 34% had a significant elevated hsTnT ≥ 14 ng/L. Increased septal wall thickness was associated with increased hsTnT plasma levels (p < 0.001). The median NT-proBNP concentration was 31 ng/L (5 to 775 ng/L) and 14% had significant elevated NT-proBNP ≥ 125 ng/L. Markers of increased left ventricular filling pressure (trans mitral E/A and lateral E/E' ratio) were associated with increased NT-proBNP plasma levels (p = 0.01 and p = 0.01). Length of GAA or the SARA score were not associated with hsTnT or NT-proBNP plasma levels. CONCLUSION: hsTnT was increased in 1/3 of the adult FA and associated with increased septal wall thickness. Increased NT-proBNP remained a marker of increased left ventricular filling pressure. This could be used to identify patients that should undergo a closer cardiac surveillance.

Non-linearity and gaps in results distribution over successive Roche Lipase method applications: improvement but persistence.

Non-linearity within the primary measurement range of a lipase assay (<300 U/L) has been shown on Cobas® Roche analyzers, causing gaps in results distribution between 300 and 400 U/L. Since, new lipase method applications (LMAs) have been used. The purpose is to retrospectively evaluate their impact on relative frequencies of lipase results (RFLs).Plasma lipase results from two hospital laboratories, assayed over 7.2 years, were collected. Over this period, three successive LMAs, characterized by automated repeat-on-dilution (1/11, 1/2, or 1/10), were applied for lipase results >300 U/L: LMA1 and LMA2 on the Modular®P800, Cobas®c501 and Cobas®C701 analyzers, and LMA3 on the Cobas®C701. RFLs were determined, linearity tests were performed, and inter-agreements between lipase results corrected and uncorrected for nonlinear biases were assessed, using 180 U/L as a decisional cut-off for acute pancreatitis.Overall, RFL gaps narrowed from LMA1 (300 to ∼380 U/L) to LMA3 (300 to ∼330 U/L). For a lipase activity fixed at 300 U/L, non-linearity biases were determined at -11.2% on the Modular®P800 (LMA1), -20.8% on the Cobas®c501 (LMA1), and -3.5% (LMA2) and -2.2% (LM3) on the Cobas®C701. Diagnostically, a maximum of 0.48% lipase results were misclassified as negative (LMA1 on the Cobas®c501), and a minimum of 0.01% misclassified as negative (LMA3 on the Cobas®C701). In conclusion, successive Roche lipase method applications improved linearity within the primary measurement range. While persisting, gaps in lipase results distribution narrowed with the evolution of the methods, with a minor impact in terms of diagnostic of acute pancreatitis.

High-Sensitivity Cardiac Troponin T: a Preanalytical Evaluation.

BACKGROUND: Little is known about the effects of preanalytical conditions on high-sensitivity cardiac troponin T (hs-cTnT) concentrations. METHODS: Variations of hs-cTnT concentrations were evaluated under the following preanalytical conditions: 1) serum vs. lithium-heparin (Li-Hep) plasma, with or without separator gel; 2) centrifugation time (15-minutes vs. 10-minutes) and speed (1467 to 3756 g); 3) stability in Li-Hep plasma at room temperature and +4 degrees C for 4 days and at -80 degrees C for up to 12 months, for three concentrations; 4) four freeze-thaw cycles at -20 degrees C and -80 degrees C, for three concentrations. RESULTS: No significant changes were found regarding the type of blood collection tube, the centrifugation, and storage conditions. Minor decreases were observed after four freeze-thaw cycles at -20 degrees C (< 6.5%) and -80 degrees C (< 3.4%). CONCLUSIONS: High-sensitivity cardiac troponin T may be considered as not impacted by usual preanalytical conditions, thus strengthening its reliability in laboratory practice and clinical research.

Stability of Routine Biochemical Analytes in Whole Blood and Plasma From Lithium Heparin Gel Tubes During 6-hr Storage.

BACKGROUND: The stability of biochemical analytes has already been investigated, but results strongly differ depending on parameters, methodologies, and sample storage times. We investigated the stability for many biochemical parameters after different storage times of both whole blood and plasma, in order to define acceptable pre- and postcentrifugation delays in hospital laboratories. METHODS: Twenty-four analytes were measured (Modular® Roche analyzer) in plasma obtained from blood collected into lithium heparin gel tubes, after 2-6 hr of storage at room temperature either before (n = 28: stability in whole blood) or after (n = 21: stability in plasma) centrifugation. Variations in concentrations were expressed as mean bias from baseline, using the analytical change limit (ACL%) or the reference change value (RCV%) as acceptance limit. RESULTS: In tubes stored before centrifugation, mean plasma concentrations significantly decreased after 3 hr for phosphorus (-6.1% [95% CI: -7.4 to -4.7%]; ACL 4.62%) and lactate dehydrogenase (LDH; -5.7% [95% CI: -7.4 to -4.1%]; ACL 5.17%), and slightly decreased after 6 hr for potassium (-2.9% [95% CI: -5.3 to -0.5%]; ACL 4.13%). In plasma stored after centrifugation, mean concentrations decreased after 6 hr for bicarbonates (-19.7% [95% CI: -22.9 to -16.5%]; ACL 15.4%), and moderately increased after 4 hr for LDH (+6.0% [95% CI: +4.3 to +7.6%]; ACL 5.17%). Based on RCV, all the analytes can be considered stable up to 6 hr, whether before or after centrifugation. CONCLUSION: This study proposes acceptable delays for most biochemical tests on lithium heparin gel tubes arriving at the laboratory or needing to be reanalyzed.

Hemolysis indexes for biochemical tests and immunoassays on Roche analyzers: determination of allowable interference limits according to different calculation methods.

OBJECTIVES: To determine the hemolysis interference on biochemical tests and immunoassays performed on Roche Diagnostics analyzers, according to different maximum allowable limits. DESIGN AND METHODS: Heparinized plasma and serum pools, free of interferences, were overloaded by increasing amounts of a hemoglobin-titrated hemolysate. This interference was evaluated for 45 analytes using Modular(®) and Cobas(®) analyzers. For each parameter, the hemolysis index (HI) corresponding to the traditional ± 10% change of concentrations from baseline (± 10%Δ) was determined, as well as those corresponding to the analytical change limit (ACL), and to the reference change value (RCV). Then, the relative frequencies distribution (% RFD) of hemolyzed tests performed in a hospital laboratory over a 25-day period were established for each HI as allowable limit. RESULTS: Considering the ± 10%Δ, the analyte concentrations enhanced by hemolysis were: Lactate dehydrogenase (LDH), aspartate aminotransferase (AST), folate, potassium, creatine kinase, phosphorus, iron, alanine aminotransferase, lipase, magnesium and triglycerides, decreasingly. The analyte concentrations decreased by hemolysis were: Haptoglobin, high-sensitive troponin T and alkaline phosphatase. Over the 25-day period, the % RFD of tests impacted more than 10%Δ by hemolysis were < 7% for LDH; < 5% for AST, folates and iron; and < 1% for the other analytes. Considering the ACL, HI were lower, giving % RFD substantially increased for many analytes, whereas only four analytes remain sensitive to hemolysis when considering RCV. CONCLUSION: This study proposes new HI based on different allowable limits, and can therefore serve as a starting point for future harmonization of hemolysis interference evaluation needed in routine laboratory practice.