Effects of different exercise methods of calf muscles on the hemodynamics of lower extremity vein

OBJECTIVE

To compare the effects of active and passive calf muscle contraction on the hemodynamics of the lower extremity vein.

METHODS

30 females were selected by convenient sampling. The hemodynamic indexes of the common femoral vein were measured by Duplex ultrasound during the active ankle pump exercise, active circular exercise, passive ankle pump exercise, passive circular exercise, and massage the calf muscles.

RESULTS

There was no significant difference in the velocity of common femoral vein when the subjects do active ankle pump exercise, active circular exercise, and massage the calf muscles (p > .05), but the velocity of common femoral vein was faster than that of passive ankle pump exercise and passive circular exercise (p < .01).

CONCLUSION

The effects of active ankle exercise and massage on promoting venous blood return of lower extremity are better than that of passive ankle exercise.

Pathophysiology of deep vein thrombosis

Deep venous thrombosis is a frequent, multifactorial disease and a leading cause of morbidity and mortality. Most of the time deep venous thrombosis is triggered by the interaction between acquired risk factors, such as hip fracture, pregnancy, and immobility, and hereditary risk factors such as thrombophilias. The mechanisms underlying deep venous thrombosis are not fully elucidated; however, in recent years, important advances have shed light on the role of venous flow, endothelium, platelets, leukocytes, and the interaction between inflammation and hemostasis. It has been described that the alteration of venous blood flow produces endothelial activation, favoring the adhesion of platelets and leukocytes, which, through tissue factor expression and neutrophil extracellular traps formation, contribute to the activation of coagulation, trapping more cells, such as red blood cells. Thus, the concerted interaction of these phenomena allows the formation and growth of the thrombus. In this work, the main mechanisms involved in the pathophysiology of deep vein thrombosis will be described.

Admission prevalence of deep vein thrombosis in elderly Chinese patients with hip fracture and a new predictor based on risk factors for thrombosis screening

BACKGROUND

Elderly hip fracture (HF) patients are at very high risk of developing deep vein thrombosis (DVT), which increases their perioperative mortality. However, data focusing on the admission prevalence of DVT in elderly Chinese patients with hip fracture are limited. Venography and ultrasonography are not suitable for most elderly HF patients; there is also controversy about the prognostic value of D-dimer in elderly patients. Thus, our primary goal was to clarify the prevalence of and risk factors for DVT in elderly Chinese HF patients at admission. Our secondary goal was to evaluate the diagnostic value of a new predictor of DVT based on the risk factors for elderly HF patients.

METHODS

This retrospective study was conducted in the West China Hospital, Sichuan University. Between January 2015 and January 2017, 248 elderly Chinese HF patients (> 60 years) were enrolled in this study. The subjects were diagnosed with DVT using ultrasonography or venography. All the patients' clinical data were obtained, including demographic variables, medical history, comorbidities, and laboratory results. A stepwise multiple logistic regression analysis was used to identify the risk factors contributing to the occurrence of DVT. The value of the new DVT predictor was calculated using a formula based on the coefficient regression and independent variables. A receiver operating characteristic (ROC) curve analysis was used to determine the diagnostic value of different factors.

RESULTS

Of the study patients, 74 (29.8%) were diagnosed with DVT, including sixty-five (87.8%) with distal peripheral, five (6.8%) with proximal central and four (5.4%) with mixed DVT. A multivariate logistic regression analysis showed that five risk factors increased the occurrence of DVT at admission, including gender, age, time from injury to admission, fibrinogen, and D-dimer. The new DVT predictor was calculated using the following formula: 1.131× (female = 1, male = 0) + 0.071 × age (years) + 0.571 × time from injury to admission (days) + 1.028 × fibrinogen(g/L) + 0.123 × D-dimer(g/L). The diagnostic value of the new predictor was highest among those risk predictors whose AUC (area under the ROC curves) value was 0.852.

CONCLUSIONS

The results of this study revealed a high prevalence of DVT in elderly Chinese HF patients at admission. Moreover, the new predictor, based on risk factors, was a good method to improve the diagnosis of DVT.

Amniotic fluid as a potent activator of blood coagulation and platelet aggregation: Study with rotational thromboelastometry

INTRODUCTION

Pulmonary thromboembolism (PTE) is a leading cause of maternal death and frequently occurs during early puerperium. Amniotic fluid components are frequently observed in the maternal circulation in parturition; however, it currently remains unclear whether amniotic fluid contamination in maternal blood is related to the high incidence of PTE in early postpartum.

OBJECTIVES

To examine the influence of amniotic fluid on blood coagulation and fibrinolysis systems with thromboelastometry.

MATERIALS AND METHODS

Twenty-one pregnant women were recruited. We used whole citrated blood in ROTEM® (Tem Innovations GmbH, Munich, Germany), including the non-activated assay (NATEM), assessments for extrinsic (EXTEM) and intrinsic pathways (INTEM), fibrin polymerization (FIBTEM), and hyperfibrinolysis (APTEM), with amniotic fluid contamination, and measured the clotting time (CT), clot formation time (CFT), alpha, amplitude at 10 min (A10), maximum clot firmness (MCF), and lysis indices at 30 min (LI30) and 60 min (LI60).

RESULTS

Short CT in all assays as well as short CFT, high alpha, and increased A10 and MCF in NATEM were observed with amniotic fluid contamination. A10 and MCF as well as LI30 and LI60 decreased in EXTEM. Decreased LI60 with the mixture of amniotic fluid was not improved by tranexamic acid in APTEM.

CONCLUSIONS

Amniotic fluid accelerated thrombin production and activated platelet aggregation without inducing hyperfibrinolysis in whole blood. The activated tissue factor pathway with amniotic fluid produced soft and fragile clots due to its influence on platelets, which may be associated with, at least partly, the high incidence of PTE in early puerperium, particularly after cesarean section.

Economic Evaluations of Thrombophilia Screening Prior to Prescribing Combined Oral Contraceptives: A Systematic and Critical Review

BACKGROUND

Combined oral contraceptives (COCs) increase the risk of venous thromboembolism (VTE), particularly among women with inherited clotting disorders. The World Health Organization classifies combined hormonal contraception as an "unacceptable health risk" for women with thrombogenic mutations but advises against universal thrombophilia screening before prescribing COCs given the low prevalence of thrombophilia and high screening costs.

OBJECTIVE

Through the lens of lifetime costs and benefits, this paper systematically and critically reviews all published economic evaluations of thrombophilia screening prior to prescribing COCs.

METHODS

We searched relevant databases for economic evaluations of thrombophilia screening before prescribing COCs. After extracting the key study characteristics and economic variables, we evaluated each article using the Quality of Health Economic Studies (QHES) and the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) instruments.

RESULTS

Seven economic evaluations of thrombophilia screening before prescribing COCs met our inclusion criteria. Only the two economic evaluations focusing exclusively on selective screening exceeded the 75-point threshold for high-quality economic studies based on the QHES instrument, whereas only one of these exceeded the 85% CHEERS threshold. Only three of the seven economic evaluations performed sensitivity analysis on key parameters. Most studies underestimated the benefits of thrombophilia screening by comparing one-time costs of genetic screening against benefits per person-year, thus implicitly assuming a 1-year duration of COC use, neglecting the long-term implications of VTE and/or neglecting the lifetime benefits of awareness of inherited thrombophilia.

CONCLUSION

Our review highlights the lack of methodologically rigorous economic evaluations of universal thrombophilia screening before prescribing COCs.

Catheter Failure and Mortality in Hemodialysis Patients with Tunneled Cuffed Venous Catheters in a Single Center

Background: As of now, only a few studies have focused on the failure of tunneled cuffed venous catheter (tCVC) and mortality of hemodialysis (HD) patients using tCVC as long-term vascular access, whose vascular condition for arteriovenous fistula was not very satisfactory. In this study, we aimed to provide information about the first tCVC failure and survival rates of patients in this population. Methods: Fifty-nine patients who used tCVC from January 1, 2009 to December 31, 2014 in our HD center were analyzed in this retrospective study and followed up either until their death or until December 31, 2015. The first tCVC and patient survival rates were analyzed. Results: The incidence of catheter-related infections was 0.3 per 1,000 patient-days. The median survival duration of first tCVC was 45.0 (95% CI 29.3-69.7) months and the median survival time of all patients was 56.3 (95% CI 34.1-78.5) months by Kaplan-Meier analysis. Advanced age (hazard ratio [HR] 1.055, p < 0.05) and diabetic mellitus (HR 4.147, p < 0.05) at the initiation of HD were significant risk factors of first tCVC failure, while male (HR 2.712, p < 0.05) and cardiovascular diseases (CVDs; HR 4.139, p < 0.05) were significant risk factors for patient mortality as deduced by Cox proportional hazards methods. Conclusions: The study highlighted that first tCVC survival rates and patient survival rates were high in HD patients who were using tCVCs as long-term vascular access, with low incidence of catheter-related infections. In the study it was found that advanced age and diabetic mellitus at the initiation of HD influenced first tCVC failure, whereas male and CVDs seemed to be risk factors for patient mortality.

A Novel Prioritization Method in Identifying Recurrent Venous Thromboembolism-Related Genes

Identifying the genes involved in venous thromboembolism (VTE) recurrence is important not only for understanding the pathogenesis but also for discovering the therapeutic targets. We proposed a novel prioritization method called Function-Interaction-Pearson (FIP) by creating gene-disease similarity scores to prioritize candidate genes underling VTE. The scores were calculated by integrating and optimizing three types of resources including gene expression, gene ontology and protein-protein interaction. As a result, 124 out of top 200 prioritized candidate genes had been confirmed in literature, among which there were 34 antithrombotic drug targets. Compared with two well-known gene prioritization tools Endeavour and ToppNet, FIP was shown to have better performance. The approach provides a valuable alternative for drug targets discovery and disease therapy.