Anti-Xa Activity Test Is Needed but Is Not Enough for Monitoring Fondaparinux Therapy Among Critically Ill Patients.

CONTEXT.­: Fondaparinux monitoring is not required among noncritically ill patients due to a predictable dose-response effect. However, this is debatable among critically ill patients, because fondaparinux bioavailability can be influenced by complicated medical conditions. OBJECTIVE.­: To investigate fondaparinux monitoring among the critically ill. DESIGN.­: Retrospective analysis of patients admitted in intensive care unit from February 2021 to December 2021, who received prophylactic fondaparinux and had anti-Xa activity tests. RESULTS.­: Of 156 anti-Xa values, 86 (55.1%) were within 0.10-0.50 µg/mL (the recommended prophylactic range), 38 (24.4%) were less than 0.10 µg/mL, 32 (20.5%) were greater than 0.50 µg/mL, demonstrating an unpredictable dose-response effect. Among 70 patients, thrombotic tendency was controlled in 32 (45.7%), thrombosis progressed in 22 (31.4%), bleeding events occurred in 16 (22.9%). Patients with progressed thrombosis had 17 of 54 (31.5%) anti-Xa less than 0.10 µg/mL, even though this proportion was greater than that of patients with controlled thrombotic tendency (11 of 72, 15.3%), it was similar to that of patients with bleeding (10 of 30, 33.3%), indicating a weak practicability of anti-Xa for monitoring fondaparinux efficacy. Thrombin-antithrombin complex showed a gradual decline among patients with controlled thrombotic tendency, but a bounce-back effect among patients with progressed thrombosis. Thrombelastography R value above the upper reference value occurred more frequently among patients with bleeding (4 of 6, 66.7%) compared to patients without bleeding (4 of 22, 18.2%) (P = .01). CONCLUSIONS.­: The fondaparinux dose-response effect was unpredictable among the critically ill; anti-Xa activity combined with thrombin-antithrombin complex and thrombelastography can be helpful to guide a precise fondaparinux therapy in this population.

A Triple-Heterozygous ß-Thalassemia Patient Demonstrated an Unusual Electrophoresis Pattern Due to a Novel ß0 Mutation [an IVS-II-654 (C>T) mutation with a Hb Zürich-Langstrasse (HBB: c.151A>T) mutation in cis].

ß-Thalassemia (ß-thal) is caused by mutations on the ß-globin genes, causing reduced (ß+) or absent (ß0) synthesis of the ß chains of hemoglobin (Hb). In this report, a 28-year-old male patient with anemia and jaundice, was diagnosed with triple-heterozygous ß-thal [an IVS-II-654 (C>T) mutation, a Hb Zürich-Langstrasse (HBB: c.151A>T) mutation and a Hb G-Siriraj (HBB: c.22G>A) mutation] by gene sequencing. However, his electrophoresis pattern was unusual: 90.8% Hb G-Siriraj, 5.9% Hb A2, 3.3% Hb F, no Hb A, no Hb Zürich-Langstrasse. His mother carried a ß-thal trait (ßA/ßIVS-II-654) having mild anemia, with a classical electrophoresis pattern (95.1% Hb A, 4.4% Hb A2, 0.5% Hb F). His father was heterozygous for Hb G-Siriraj (ßA/ßG-Siriraj) but asymptomatic, with a corresponding electrophoresis pattern (63.9% Hb A, 3.5% Hb A2, 32.6% Hb G-Siriraj). In view of the family study results, the Hb Zürich-Langstrasse mutation in the proband was considered a de novo mutation occurring on the ßIVS-II-654 allele that he inherited from his mother, resulting in a ßIVS-II-654/Hb Zürich-Langstrasse genotype, which should be interpreted as a novel ß0 mutation. This report illustrates that mutations in cis can confound genotype-phenotype correlations, therefore, just as DNA testing and Hb analysis, family study is also indispensable to the accurate identification of ß-thal mutations.

Evaluation of Activated Partial Thromboplastin Time Mixing Studies Using Several Methods.

CONTEXT.­: A prolonged activated partial thromboplastin time (APTT), a vital screening test for coagulation, can be due to deficiencies in coagulation factors and the existence of factor inhibitors or antiphospholipid antibodies. APTT mixing studies are being optimized to help find the cause. OBJECTIVE.­: To optimize APTT mixing studies, we evaluated existing standards and explored when and how to combine 1:1 and 4:1 mixing. DESIGN.­: Patients with a prolonged APTT but otherwise normal prothrombin time and thrombin time were enrolled in our hospital from January 1, 2018, to December 31, 2019. All samples were subjected to 1:1 mixing studies, while 134 were subjected to 4:1. RESULTS.­: A total of 251 samples were involved, including 116 with factor deficiencies, 75 with FVIII inhibitors, and 60 with antiphospholipid antibodies. A Rosner index less than 11% or an extended incubation time of more than 3 seconds was better than other existing standards in differentiating factor deficiencies from inhibitors and in differentiating time-dependent inhibitors from time-independent inhibitors, but the approach presented here improves upon those. For the best diagnostic accuracy, samples with a Rosner index between 5.0% and 9.1% need a 4:1 mixing study, while others need 1:1. A combination of Rosner index and percent-extended incubation time-P seemed to offer objective and effective criteria for interpreting the results. CONCLUSIONS.­: APTT mixing studies had overall good sensitivity and specificity in differentiating factor deficiencies from inhibitors, or time-dependent from time-independent inhibitors. The combination of 1:1 and 4:1 mixing studies can improve the diagnostic ability compared with 1:1 alone.

Interpretation of clot-based lupus anticoagulant assays-Normalizing clotting time against different denominators.

OBJECTIVES: The endpoint for all lupus anticoagulant (LA) assays is a clotting time in seconds. This study aimed to clarify the use of normalizing clotting time to ratio and how the use of different denominators is relevant. METHODS: Whether normalization could reduce reagent variability and possess better diagnostic performances was assessed; denominators included reference interval (RI) mean, local-obtained pooled plasma clotting time, standard plasma clotting time, and control plasma clotting time (CNPPct). Moreover, whether day-to-day variation in CNPPct would impact its application was studied. RESULTS: If not normalized, significant difference existed among different reagent batches; if normalized (against any denominators), no statistically significant difference existed anymore. The validation of in-house RIs achieved a 100% success rate. Normalization against different denominators had different RIs, but the same diagnostic efficacies (when a prolonged LA1 is used to suggest further LA-related testings, normalized LA1 demonstrated a better sensitivity: 1.0 vs. 0.95). Normalization against a "daily" CNPPct (obtained alongside test plasmas day to day) demonstrated low inter-day variations (LA1: ~1%, LA2: ~1%), and it could employ the RI for normalization against a "fixed" CNPPct (obtained alongside normal plasmas when the RI was established). CONCLUSIONS: Normalizing clotting time reduces reagent-batch variability and promotes the adoption of common RIs, and therefore reduces the necessity of establishing RI for new reagent batches. Normalized LA1 is more sensitive when used to suggest further LA-related testings, and therefore reduces the rate of missed LA diagnosis. All denominators are of the same application value. Day-to-day variation in CNPPct did not impact its application as a reliable denominator.

Monitoring coagulation-fibrinolysis activation prompted timely diagnosis of hemophagocytic lymphohistiocytosis-related disseminated intravascular coagulation.

BACKGROUND: Timely diagnosis of disseminated intravascular coagulation (DIC) in hemophagocytic lymphohistiocytosis (HLH) patients is crucial but challenging, as HLH interferes with the results of the laboratory tests included in the DIC score system. CASE PRESENTATION: Here, we reported a case of lymphoma-associated HLH, in which coagulation-fibrinolysis activation /inhibition markers (TAT, tPAIC, and PIC), prompted timely diagnosis of early stage DIC (initial phase of microvascular thrombosis, yet non-overt), prior to the development of organ failures and/or bleedings. CONCLUSIONS: This report highlights the importance of the implementation of new biomarkers (such as TAT, tPAIC, and PIC), into the diagnostic work-up for coagulation disorders. These biomarkers are directly suggestive of microthrombus formation, therefore they can be of paramount importance in diagnosing DIC with complicated etiologies, such as hematological diseases-related DIC.

[Clinical Value of Cystatin C-Based Estimated Glomerular Filtration Rate in Assessing Short-Term Mortality in Patients with Hepatitis B Virus-Related Acute-on-Chronic Liver Failure Treated with Artificial Liver Support System].

OBJECTIVE: To evaluate the predictive value of using cystatin c-based estimated glomerular filtration rate (eGFR-CysC) in assessing the prognosis of hepatitis B virus-associated acute-on-chronic liver failure (HBV-ACLF) patients treated with artificial liver support system (ALSS). METHODS: A total of 364 HBV-ACLF inpatients treated with ALSS at our hospital were enrolled retrospectively in the study. The patients were divided into the survival group ( n=269) and non-survival group ( n=95) according to mortality within 28 d, and their clinical information and laboratory data were analyzed for assessing short-term prognostic values. RESULTS: Multivariate Cox regression analysis identified eGFR-CysC as one of the independent risk factors associated with mortality within 28 days in HBV-ACLF patients (the hazard ratio=0.987; 95% confidence interval, 0.979-0.996, P=0.003). In addition, baseline eGFR-CysC was negatively correlated with the model for end-stage liver disease (MELD) score ( r=-0.439, P<0.001), MELD plus sodium (MELD-Na) score ( r=-0.481, P<0.001) and Chronic Liver Failure Consortium ACLF (CLIF-C ACLF) score ( r=-0.340, P<0.001). Receiver operating characteristic (ROC) curve analysis showed area under the curve ( AUC) of eGFR-CysC were 0.639, 0.697, 0.716, 0.749 and the best cut-off value were 70.620, 67.525, 61.725, 64.685 mL/(min·1.73 m 2), respectively, for baseline value and the first, second, and third treatment with ALSS. CONCLUSION: eGFR-CysC could be used to assist clinical assessment of short-term mortality in HBV-ACLF patients treated with ALSS, and has better clinical application value for dynamic monitoring.

Platelet-leukocyte aggregates - a predictor for acute kidney injury after cardiac surgery.

BACKGROUND: Acute kidney injury (AKI) is one of the most common complications after cardiac surgery. However, effective biomarker used for early diagnosis of AKI has not been identified. Platelet-leukocyte aggregates (PLAs) participate in inflammation and coagulation, leading to vascular lesions and tissue destruction. We designed a prospective study to assess whether PLAs can serve as a good biomarker for early diagnosis of AKI after cardiac surgery. METHODS: Patients with rheumatic heart disease scheduled to undergo valve replacement surgery were enrolled. Blood samples were collected at five timepoints as follows: (a) At baseline. (b) At the end of extracorporeal circulation. (c) Arrival at intensive care unit (ICU). (d) Four-hours after the admission to ICU. (e) Twenty hours after the admission to ICU. After collection, the samples were immediately used for PLAs measurement by flow cytometry. RESULTS: A total of 244 patients were registered, and 15 of them were diagnosed with AKI according to the serum creatinine of KDIGO guidelines. The PLAs levels in AKI group were significantly increased 20 h after surgery (two-way repeated measure analysis of variance, p < 0.01) compared with that at baseline. Patients whose preoperative PLAs were higher than 6.8% showed increased risk of developing AKI (multivariate logistic regression; p = 0.01; adjusted odds ratio, 1.05; 95% confidence interval, 1.01-1.09). CONCLUSION: PLAs is an independent risk factor for AKI after valve replacement among patients with rheumatic heart disease.

[Genotype of Thalassemia in Han Chinese and Tibetans in Sichuan Province,China.]

OBJECTIVES: To investigate the carrying rates and genotype distribution of thalassemia gene in Han people and Tibetans in Sichuan district. METHODS: A total of 1 147 Han adults and 613 adult Tibetans were included in this study.Hematological parameters were measured with Sysmex XE-2100 automatic blood cell analyzer.Alpha thalassemia and beta thalassemia gene analyses were further performed on samples with a mean corpuscular volume (MCV) <85 fL and a mean corpuscular hemoglobin (MCH) <27 pg.Multiplex ligation-dependent probe amplification (MLPA) and reverse dot blot assays were used for detecting deletional mutations of α globin gene and non-deletional mutations of α globin and ß globin genes,respectively. RESULTS: About 1.48% (17/1 147) Han people carried alpha thalassemia gene,with --SEA/αα as the most common genotype; 1.39% (16/1 147) carried beta thalassemia gene,with CD17 and IVS-2-654 as the most common genotype.There were 2 cases with both alpha and beta thalassemia.Low MCH (<27 pg) was found in all 33 cases with positive thalassemia genes.However,5 people with positive thalassemia genes had higher than 80 fL MCV,with the highest reaching 83.7 fL.Out of 613 Tibetans,only one was found to have positive thalassemia genes. CONCLUSIONS: Sichuan Han population carry a high level of thalassemia genes,with various genotypes and pathogenic gene mutation types.Han people with < 84 fL MCV and <27 pg MCH were recommended for thalassemia gene screening.Tibetans were not recommended for routine screening of thalassemia.

Warfarin dosage response related pharmacogenetics in Chinese population.

OBJECTIVES: As the most frequently prescribed anticoagulant, warfarin has large inter-individual variability in dosage. Genetic polymorphisms could largely explain the differences in dosage requirement. rs9923231 (VKORC1), rs7294 (VKORC1), rs1057910 (CYP2C9), rs2108622 (CYP4F2), and rs699664 (GGCX) involved in the warfarin action mechanism and the circulatory vitamin K were selected to investigate their polymorphism characteristics and their effects on the pharmacodynamics and pharmacokinetics of warfarin in Chinese population. METHODS: 220 patients with cardiac valve replacement were recruited. International normalized ratio and plasma warfarin concentrations were determined. The five genetic polymorphisms were genotyping by pyro-sequencing. The relationships of maintenance dose, plasma warfarin concentration and INR were assessed among groups categorized by genotypes. RESULTS: rs9923231 and rs7294 in VKORC1 had the analogous genotype frequencies (D': 0.969). 158 of 220 recruited individuals had the target INR (1.5-2.5). Patients with AA of rs9923231 and CC of rs7294 required a significantly lower maintenance dose and plasma concentration than those with AG and TC, respectively. The mean weekly maintenance dose was also significantly lower in CYP2C9 rs1057910 mutated heterozygote than in patients with the wild homozygote. Eliminating the influence from environment factors (age, body weight and gender), rs9923231 and rs1057910 could explain about 32.0% of the variability in warfarin maintenance dose; rs7294 could explain 26.7% of the variability in plasma concentration. For patients with allele G of rs9923231 and allele T of rs7294, higher plasma concentration was needed to achieve the similar goal INR. CONCLUSIONS: A better understanding of the genetic variants in individuals can be the foundation of warfarin dosing algorithm and facilitate the reasonable and effective use of warfarin in Chinese.

Differences in platelet indices between healthy Han population and Tibetans in China.

INTRODUCTION: The present data on the evaluation of platelet (PLT) parameters in Chinese Han population and Tibetans are still limited. The objective of this study was to determine the differences in common PLT indices between Han population and Tibetans in China, through a large-scale investigation of healthy people. METHODS: 2131 Han people from Chengdu Plain, 1099 Tibetans from Qinghai-Tibet Plateau and 956 Plateau Han migrants were included in this study. All the subjects were healthy people through the health screening. PLT indices were measured with Sysmex XE-2100 and XT-1800i blood cell automatic analyzer. RESULTS: Compared with Han people in Chendu Plain, Tibetans had higher PLT count (P<0.01) but lower mean platelet volume (MPV), platelet distribution width (PDW) and platelet-large cell ratio (P-LCR) (P<0.01); while Plateau Han migrants had lower PLT count, MPV and P-LCR (P<0.05). When compared with Tibetans, Plateau Han migrants had lower levels of mean PLT count but higher PDW and P-LCR (P<0.05). CONCLUSIONS: There are ethnic differences in PLT indices between Chinese Han population and Tibetans. Based on this finding, it would be reasonable to conduct formal prospective studies to determine the clinical significance of these differences and to explore the effects of genetic background on these indices.

Serum procalcitonin predicts development of acute kidney injury in patients with suspected infection.

BACKGROUND: Procalcitonin (PCT) is an early, sensitive, and accurate marker for diagnosing infection and sepsis. As sepsis and septic shock are dominant causes of acute kidney injury (AKI), we investigated whether PCT is an early predictor of AKI in patients with symptoms of infection. METHODS: Between January 2011 and October 2011, 1361 inpatients in West China Hospital who displayed infection symptoms were enrolled in our study. Levels of PCT, serum amyloid A (SAA), C-reactive protein (CRP), interleukin-6 (IL-6), and white blood cell count (WBC) were determined and participants' renal function was monitored for 3 consecutive days. RESULTS: The rate of AKI occurrence 3 days after enrollment was 14.6%. Higher PCT levels were correlated with higher AKI occurrence rates and higher levels of serum urea, creatinine, and cystatin C (p<0.05). The area under the receiver-operating characteristic (ROC) curve (AUC) for PCT was 0.823, making it more predictive (p<0.0001) than SAA, CRP, IL-6, or WBC. The cut-off value of 1.575 ng/mL for PCT had the highest validity for predicting AKI in patients with infection symptoms. The sensitivity, specificity, negative-predictive value (NPV), positive-predictive value (PPV), negative-likelihood ratio (LR-), and positive-likelihood ratio (LR+) for this cut-off value were 61.7%, 84.6%, 93.6%, 37.5%, 0.415, and 4.98, respectively. CONCLUSIONS: PCT can be used as a predictive marker for sepsis-induced acute kidney injury in patients with symptoms of infection.