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Luqian Zhan,1,&ast; Ye Zhang,2,&ast; Yanwei Li,3 Chenhui Lin,3 Heyu Zhang,3 Yuntao Liu,3 Jincai He3 1Department of Neurology, Integrated Traditional Chinese and Western Medicine Hospital of Wenzhou Medical University, Wenzhou, People’s Republic of China; 2Third Department of Cerebrovascular Disease, Cangzhou Central Hospital, Cangzhou, People’s Republic of China; 3Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Jincai He; Yuntao Liu, Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, People’s Republic of China, Email hjc@wmu.edu.cn; 18267850815@163.comPurpose: Acute ischemic stroke (AIS) patients with COVID-19 have severe neurological symptoms and high mortality. It remains unclear how COVID-19 causes unfavorable outcomes. This study aimed to explore the possible mechanism focusing on inflammation and coagulation.Patients and Methods: 109 AIS patients were recruited and followed up 3 months after stroke. We used binary logistic regression to investigate if COVID-19 infection is an independent prognostic factor. To analyze the link between inflammation, coagulation, and neurological outcomes, we used mediation analysis.Results: Compared to the non-COVID-19 group, the COVID-19 group had significantly higher fibrinogen (FIB) (P < 0.001), APTT ratio (P < 0.001), D-dimer (P < 0.001), CRP (P < 0.001). Patients with unfavorable outcomes had a higher incidence of COVID-19 infection (P = 0.002), along with elevated levels of INR (P = 0.005), D-dimer (P < 0.001), and CRP (P = 0.012). The significant association between 3-month functional outcomes and COVID-19 tends to be insignificant (P = 0.294) after adding the covariates of inflammation and coagulation. The mediation analyses showed the APTT ratio mediated the association between COVID-19 and the 3-month outcome (percent mediation = 56.3%). The integrated pathway analysis implicated that the path of COVID-19 infection→CRP→APTT ratio→ 3-month outcome was significant (percent mediation = 18.7%).Conclusion: AIS with COVID-19 had a poorer prognosis. We delineated a more accurate mechanism by which COVID-19 influences functional outcomes: COVID-19 infection→inflammation→endogenous coagulation pathway→poor stroke outcome. This study provided new insight into the pathway mechanisms of AIS with COVID-19.Keywords: COVID-19, Omicron, stroke, mediation analysis, APTT ratio

Background: Significant errors of activated partial thromboplastin time (aPTT) ratio were frequently observed in blood sampling from central venous dialysis catheter (CVC) of hemodialysis (HD) patients. Following the draw-and-return methods, initial blood withdrawal from the catheter before sampling can reduce the error, but the optimal withdrawal volume remains undetermined. Aim: The objective of this study is to determine the optimal blood withdrawal volume for the draw-and-return methods to improve aPTT ratio accuracy in hemodialysis patients with CVC. Methods: A prospective study was conducted in patients receiving HD via CVC. Four blood samples were collected from each patient, involving a peripheral venipuncture and three draw-and-return samples (10 ml, 20 ml and 25 ml groups). The aPTT ratio of a peripheral sample was used as a reference to determine the aPTT ratio accuracy for each draw-and-return group. Subsequently, the agreement was illustrated using modified Bland-Altman plot. Results: A total of 1,000 samples were obtained from 250 patients. The patients had a mean age of 59.6 ± 15.4 years, with 17.2% using citrate as the CVC's locking agent. The adjusted accuracies of the aPTT ratio varied significantly among the three withdrawal volumes (p-value

The prothrombin time (PT), International normalized ratio (INR) and activated partial thromboplastin time (APTT) are the most used coagulation tests in China, where more than one type of automated coagulation analyzer is often used in the clinical laboratory. The PT–INR results of 109 samples were compared with local mean normal PT (MNPT) and APTT ratio (APTTR) with mean normal APTT (MNAPTT) on two different coagulation analyzers in the same laboratory. The two different coagulation analyzers showed no significant difference ( P > 0.05) in PT and INR determination, but there was a significant difference ( P < 0.01) for APTT. The INR with local MNPT and APTTR with MNAPTT, obtained with the ACL Futura and CA 510, showed much better agreement; 98.8% (82/83) of bias for INR with local MNPT was less than 15% compared with 90.4% (75/83) of bias for INR; and 100% of bias for APTTR (62/62) was less than 15% compared with only 6.5% (4/62) of bias for APTT. Meanwhile, there was no significant difference ( P = 0.865) for APTTR with MNAPTT compared with APTT ( P = 0.002) between the ACL Futura and CA 510. In conclusion, these analyzers showed very poor agreement for both the PT and APTT, but the calculation of ratios significantly improved agreement. [ABSTRACT FROM AUTHOR]