Intrinsic clotting factors in dependency of age, sex, body mass index, and oral contraceptives: definition and risk of elevated clotting factor levels

Plasma levels of coagulation factors VIII and IX and risk of venous thromboembolism: Systematic review and meta-analysis

INTRODUCTION

The associations of plasma factor VIII (FVIII) and factor IX (FIX) levels with risk of venous thromboembolism (VTE) are not well defined. We performed a systematic review and meta-analysis of these associations.

METHODS

Random effects inverse-variance weighted meta-analysis was used to estimate pooled odds ratios for comparisons across equal quartiles of the distributions and 90 % thresholds (higher versus lower), and for testing linear trends.

RESULTS

Among 15 studies (5327 cases) the pooled odds ratio of VTE for the fourth versus first quarter was 3.92 (95 % confidence interval 1.61, 5.29) for FVIII level; and among 7 studies (3498 cases) 1.57 (1.32, 1.87) for FIX level. Comparing factor levels above, versus below, the 90th percentile, the estimated pooled odds ratios were 3.00 (2.10, 4.30) for FVIII; 1.77 (1.22, 2.56) for FIX; and 4.56 (2.73, 7.63) for both FVIII and FIX considered jointly.

CONCLUSIONS

We confirm increases in risk of VTE across population distributions of FVIII and FIX levels. Levels above the 90th percentile have almost twice the risk for FIX level compared to levels below; three-fold risk for FVIII level; and almost five-fold risk for both FVIII and FIX levels elevated.

Low ambient temperature might trigger the symptom onset of pulmonary embolism: A nationwide case-crossover study at hourly level in China

BACKGROUND

Pulmonary embolism (PE) is an important cause of death and its seasonality has long been observed. Very few epidemiological studies have explored the potential role of ambient temperature in PE symptom onset, especially at the hourly level.

METHODS

We conducted a time-stratified case-crossover study among 17,903 PE patients with hourly onset of symptom from 1590 hospitals across China between January 2015 and September 2020. Conditional logistic regression model combined with distributed lag non-linear models were used to explore the associations between hourly ambient temperature and PE symptom onset. The attributable fractions due to non-optimum temperature were calculated.

RESULTS

The exposure-response relationship curve was inverse and almost linear. Lower temperature was significantly associated with higher risk of PE symptom onset when temperature was below 18 °C. This risk occurred immediately at the same hour, attenuated thereafter, and became nonsignificant at approximately 72 h after exposure. Compared with the referent temperature (P₉₉, 34.1 °C), the odds ratio of PE symptom onset associated with extremely low temperature (P₁, -16.1 °C) over lag 0-72 h was 1.63 (95%CI: 1.23, 2.16). Low temperature may account for 16.19 % of the symptom onset nationally with higher proportion in the south of China. The effects were stronger in older adults, males, and cold seasons.

CONCLUSIONS

We provided the first-hand robust evidence that transient exposure (at the hourly level) to low temperature might trigger the symptom onset of PE and constitute a considerable burden for PE patients. Targeted protections and health education are needed for susceptible populations.

Haematological variables and risk of future venous thromboembolism in the British Regional Heart Study on men. Combined D-dimer and APTT as a predictive test for thromboembolism?

We examined the associations between haematological and inflammatory variables with future venous thromboembolism (VTE), in 3494 men aged 60-79 years, with no previous history of VTE or myocardial infarction, who were not receiving oral anticoagulants. After a mean follow-up period of 18 years, there were 149 confirmed cases of fatal or non-fatal VTE (deep vein thrombosis and/or pulmonary embolism). Among classical cardiovascular risk factors, only obesity and cigarette smoking were associated with VTE risk. After adjustment for age, obesity and smoking, VTE risk was associated with coagulation factor VIII, factor IX, von Willebrand factor (VWF), activated partial thromboplastin time (APTT), and fibrin D-dimer. Hazard ratios (95% CI) for top to bottom quarters (bottom to top for APTT), were respectively 2.17 (1.37, 3.44), 2.15 (1.30, 3.53), 2.02 (1.27, 3.22), 2.43 (1.47, 4.02) and 3.62 (2.18, 6.08). The 11% of men with both the shortest APTT and highest D-dimer combined had a 5.02 (2.37, 10.62) higher risk of VTE. VTE risk was not associated with fibrinogen, factor VII or activated protein C resistance; full blood count variables or with inflammatory markers, plasma viscosity, C-reactive protein or interleukin-6. The combination of D-dimer and APTT merits evaluation as an adjunct to VTE risk prediction scores.

Clinical epidemiology of venous thromboembolic disease: An institutional registry

Introduction

Venous thromboembolism (VTE) is a major health concern, with an annual incidence of ~1 in 1,000. The epidemiology of VTE in Saudi Arabia has not been adequately described yet. Therefore, this study aimed to assess the clinical characteristics, risk factors, diagnostic methods, management, and clinical outcomes of patients with VTE.

Methods

This study was based on a VTE registry created over ten years at King Fahad Medical City (KFMC) in Riyadh, Saudi Arabia. All adult inpatients and outpatients referred to the thrombosis unit of the KFMC with clinically suspected VTE including pulmonary embolism (PE) and deep vein thrombosis (DVT) were enrolled. Data were collected using a standardized case report form, which included demographic and clinical characteristics, risk factors, diagnostic methods, management, and outcomes.

Results

A total of 1,008 patients were recruited. Most patients were women (73.2%), and more than half of all patients had unprovoked VTE (58%). Among the provoked cases, the most frequent cause was surgery (29.8%), followed by hospitalization (24.2%). There was a significant statistical association between provoked status and sex, family history of VTE, smoking, recent hospitalization within 3 months for a medical condition, the site of VTE, and underlying peripheral vascular disease and varicose veins (all p < 0.05). The majority (88.3%) of patients with deep vein thrombosis was hospitalized for ≤3 days (n = 433, 79.9%), while fewer than half of the patients with PE needed hospitalization (45.3%). Thrombolytic therapy was administered to 14.1% (n = 142) of patients, and catheter-directed thrombolysis was performed in 1.0% (n = 10) of patients. The odds of mortality for provoked VTE were 3.20 times higher than those of unprovoked VTE [2.12–4.83; p-value < 0.001].

Conclusion

Unprovoked VTE was more common than provoked VTE in the Saudi Arabian cohort, implying hereditary predisposition. Furthermore, male sex, family history of VTE, prior history of VTE, type of VTE, underlying obesity, history of trauma, surgery, hospitalization, pregnancy, and 3–6 months of anticoagulation therapy were the most critical risk factors for VTE recurrence. The treatment patterns and clinical results were comparable to those reported in the literature.

Improved hemocompatibility of polysulfone hemodialyzers with Endexo® surface modifying molecules

Anticoagulation therapy is widely used to reduce clotting during hemodialysis (HD), but may cause adverse effects in end-stage kidney disease patients. A new hemodialyzer with a membrane modified by surface modifying molecule was developed to improve hemocompatibility that aimed to reduce the need for anticoagulation during dialysis treatments. We compared membrane surface characteristics and in vitro hemocompatibility of the new hemodialyzer to the standard polysulfone (PSF) hemodialyzer membrane. Scanning electron microscopy, contact angle measurement (68° ± 3° test vs. 41.6° ± 6° control), and X-ray photoelectron spectrometry measurement for fluorine atomic % (7.4% ± 0.4% test vs. not detectable control), showed that the membrane surface was modified with surface modifying macromolecule (SMM1) but maintained membrane structure and surface hydrophilicity. Zeta potential of the blood-contacting surface showed that the absolute surface charge was reduced at neutral pH (-3.3 mV ± 1.1 mV test vs. -15.6 mV ± 1.0 mV control). Platelet count reduction was significantly less for the SMM1-modified dialyzer (40.88% ± 21.89%) compared to the standard PSF dialyzer (62.62% ± 34.13%), along with Platelet Factor 4 (1824.10 ng/ml ± 436.26 ng/ml test vs. 2479.00 ng/ml ± 852.96 ng/ml control). These studies demonstrate the successful incorporation of SMM1 into the new hemodialyzer with the expected results. Our in vitro experiments indicate that the SMM1-modified hemodialyzers could improve hemocompatibility compared to standard PSF hemodialyzers and have the potential to minimize the patient's anticoagulant requirements during HD. Additional research with SMM1 additives incorporated into the entire dialysis circuit and use in a clinical settings are required to confirm these promising findings.

Effects of storage over a 36-month period on coagulation factors in a canine plasma product obtained by use of plasmapheresis

OBJECTIVE

To evaluate stability of coagulation factors in canine plasma obtained by use of plasmapheresis and stored over a 36-month period.

SAMPLE

Canine plasma obtained by use of plasmapheresis acquired from a commercial blood bank.

PROCEDURES

Coagulation testing for fibrinogen concentration and activity of factors II, V, VII, VIII, and IX and von Willebrand factor was performed on canine plasma obtained by use of plasmapheresis. Samples were obtained for testing at 6-month intervals from plasma stored for up to 36 months.

RESULTS

A simple mixed linear regression model was created for each analysis. Median value for the fibrinogen concentration was > 150 mg/dL for all time points, except at 467, 650, and 1,015 days of storage. Median value for factor VIII was > 70% only at 650 days. Median value for factor V was > 50% through 650 days. Median value for factors VII and X was > 50% through 833 days, and median value for factors II and VII was > 50% through 1,015 days. Median value for von Willebrand factor was > 50% for the entire study (1,198 days). Median value for factor X was always < 50%.

CONCLUSIONS AND CLINICAL RELEVANCE

Coagulation factors degraded over time at variable rates, and all labile factors remained at > 50% activity for longer than 1 year. Plasma collected by plasmapheresis potentially offers prolonged life span of some clotting factors. Plasmapheresis is an acceptable form of canine plasma collection for transfusion purposes, and further studies should be performed to determine all of its benefits.

Factor XII as a Risk Marker for Hemorrhagic Stroke: A Prospective Cohort Study

Background

Coagulation factor XII (FXII) is involved in pathological thrombus formation and is a suggested target of anticoagulants. It is unclear whether FXII levels are correlated with cardiovascular risk factors and whether they are associated with myocardial infarction or ischemic or hemorrhagic stroke. The aim of this study was to investigate the correlation between FXII and cardiovascular risk factors in the general population. We also aimed to study the associations between FXII levels and future myocardial infarction and ischemic and hemorrhagic stroke.

Methods

This prospective cohort study measured FXII levels in 1,852 randomly selected participants in a health survey performed in northern Sweden in 1994. Participants were followed until myocardial infarction, stroke, death, or until December 31, 2011.

Results

During the median follow-up of 17.9 years, 165 individuals were diagnosed with myocardial infarction, 108 with ischemic stroke, and 30 with hemorrhagic stroke. There were weak correlations between FXII and body mass index, cholesterol, and hypertension. There was no association between FXII and myocardial infarction or ischemic stroke, neither in univariable Cox regression analysis nor after adjustment for age, sex, smoking, body mass index, cholesterol, hypertension, and diabetes. In univariable Cox regression analysis, the hazard ratio for the association between FXII levels and hemorrhagic stroke was 1.42 per SD (95% confidence interval: 0.99–2.05). In the multivariable model, higher levels of FXII were associated with increased risk of hemorrhagic stroke (hazard ratio 1.51 per SD; 95% confidence interval: 1.03–2.21).

Conclusion

We found an independent association between FXII levels and the risk of hemorrhagic stroke, but not between FXII levels and ischemic stroke or myocardial infarction.

Environmental and Genetic Risk Factors Associated with Venous Thromboembolism

Venous thromboembolism (VTE) includes deep vein thrombosis and pulmonary embolism, and a combination of environmental and genetic risk factors contributes to VTE risk. Within environmental risk factors, some are provoking (e.g., cancer, surgery, trauma or fracture, immobilization, pregnancy and the postpartum period, long-distance travel, hospitalization, catheterization, and acute infection) and others are nonprovoking (e.g., age, sex, race/ethnicity, body mass index and obesity, oral contraceptive or hormone therapy use, corticosteroid use, statin use, diet, physical activity, sedentary time, and air pollution). Additionally, VTE has a strong genetic basis, with approximately 50 to 60% of the variance in VTE incidence attributed to genetic effects. Some genetic susceptibility variants that contribute to risk have been identified in candidate genes, mostly related to the clotting system and responsible for inherited hypercoagulable states (e.g., factor V Leiden, prothrombin, fibrinogen gamma, or blood group non-O). Other susceptibility single-nucleotide polymorphisms have been identified from genome-wide association studies, such as the two new loci in TSPAN15 (rs78707713) and SCL44A2 (rs2288904) genes. Risk factors are not always associated with VTE in isolation; however, and an understanding of how environmental and genetic factors interact may provide insight into the pathophysiology of VTE, possibly identifying opportunities for targeted prevention and treatment.

DAMPs as mediators of sterile inflammation in aging-related pathologies

Accumulating evidence indicates that aging is associated with a chronic low-level inflammation, termed sterile-inflammation. Sterile-inflammation is a form of pathogen-free inflammation caused by mechanical trauma, ischemia, stress or environmental conditions such as ultra-violet radiation. These damage-related stimuli induce the secretion of molecular agents collectively termed danger-associated molecular patterns (DAMPs). DAMPs are recognized by virtue of specialized innate immune receptors, such as toll-like receptors (TLRs) and NOD-like receptor family, pyrin domain containing 3 (NLRP3). These receptors initiate signal transduction pathways, which typically drive inflammation in response to microbe-associated molecular patterns (MAMPs) and/or DAMPs. This review summarizes the current knowledge on DAMPs-mediated sterile-inflammation, its associated downstream signaling, and discusses the possibility that DAMPs activating TLRs or NLRP3 complex mediate sterile inflammation during aging and in aging-related pathologies.

Ethanol Extract of Persimmon Tree Leaves Improves Blood Circulation and Lipid Metabolism in Rats Fed a High-Fat Diet

The leaves of the persimmon tree (PL) are known to have beneficial effects on hyperglycemia, dyslipidemia, and nonalcoholic fatty liver disease. We recently demonstrated that PL had antithrombotic properties in vitro. However, little is known about the antiplatelet and anticoagulant properties of PL in vivo. Omega-3 fatty acid (n-3 FA)-containing fish oil has been widely prescribed to improve blood circulation. This study compared the effects of dietary supplementation with an ethanol extract of PL or n-3 FA on blood coagulation, platelet activation, and lipid levels in vivo. Sprague-Dawley rats were fed a high-fat diet with either PL ethanol extract (0.5% w/w) or n-3 FA (2.5% w/w) for 9 weeks. Coagulation was examined by monitoring the activated partial thromboplastin time (aPTT) and prothrombin time. We examined plasma thromboxane B2 (TXB2), serotonin, and soluble P-selectin (sP-selectin) levels. The aPTT was significantly prolonged in the PL and n-3 FA supplement groups. PL also attenuated the TXB2 level and lowered arterial serotonin transporter mRNA expression, although it did not alter plasma serotonin or sP-selectin levels. C-reactive protein and leptin levels were significantly reduced by PL and n-3 FA supplementation. In addition, PL decreased plasma total- and low-density lipoprotein-cholesterol levels, as did n-3 FA treatment. These results indicated that the PL ethanol extract may have the potential to improve circulation by inhibiting blood coagulation and platelet activation and by reducing plasma cholesterol levels.

Prevalence of thrombophilia according to age at the first manifestation of venous thromboembolism: results from the MAISTHRO registry

Thrombophilia is a well-established risk factor for a venous thromboembolic event (VTE), and it has been proposed that hereditary thrombophilia may substantially contribute to the development of VTE in young patients. We aimed to analyse the prevalence of thrombophilia with special regard to the age of VTE manifestation. The study cohort consisted of 1490 patients (58% females) with a median age 43 years at the time of their first VTE. At least one thrombophilic disorder was identified in 50·1% of patients. The probability of detecting a hereditary thrombophilia declined significantly with advancing age (from 49·3% in patients aged 20 years and younger to 21·9% in patients over the age of 70 years; P < 0·001). This may be primarily attributed to the decreasing frequencies of the F5 R506Q (factor V Leiden) mutation and deficiencies of protein C or protein S with older age at the time of the initial VTE event. Moreover, thrombophilia was more prevalent in unprovoked compared with risk-associated VTE (57·7% vs. 47·7%; P = 0·001). The decline in the prevalence of hereditary thrombophilia with older ages supports the use of a selected thrombophilia screening strategy dependent on age and the presence or absence of additional VTE risk factors.

Extrapolation Of A Controversial Subject In Pregnancy And Puerperium: The Influence Of Combined Oral Contraceptive Use Over Body Mass Index And Biliary Symptoms

Introduction and aim: Because for the majority of women one of the most unwanted effect of combined oral contraceptive use is considered to be weight increasement, our study aim was to find out if there is a correlation between the use of combined oral contraceptives in the present or past and the body mass index in a group of pregnant, puerperal and matching control patients.

Material, patients and method: In a prospective cohort (Regional University Hospital - Constanţa), 176 patients were included in 3 groups: pregnant, puerperal and matching non-pregnant women (control). For each patient a chart was considered, with the following parameters, age, height, weight, BMI, type of diet, use of combined oral contraceptives in the present or in the past (more than 6 months), ultrasound evaluation of gallbladder’ content.

Conclusion: In our study, the use of combined oral contraceptives was not correlated with a high BMI but it seems to correlate with a higher incidence of biliary dyspeptic symptoms in patients without biliary sludge or stones.

Diet as prophylaxis and treatment for venous thromboembolism?

BACKGROUND

Both prophylaxis and treatment of venous thromboembolism (VTE: deep venous thrombosis (DVT) and pulmonary emboli (PE)) with anticoagulants are associated with significant risks of major and fatal hemorrhage. Anticoagulation treatment of VTE has been the standard of care in the USA since before 1962 when the U.S. Food and Drug Administration began requiring randomized controlled clinical trials (RCTs) showing efficacy, so efficacy trials were never required for FDA approval. In clinical trials of 'high VTE risk' surgical patients before the 1980s, anticoagulant prophylaxis was clearly beneficial (fatal pulmonary emboli (FPE) without anticoagulants = 0.99%, FPE with anticoagulants = 0.31%). However, observational studies and RCTs of 'high VTE risk' surgical patients from the 1980s until 2010 show that FPE deaths without anticoagulants are about one-fourth the rate that occurs during prophylaxis with anticoagulants (FPE without anticoagulants = 0.023%, FPE while receiving anticoagulant prophylaxis = 0.10%). Additionally, an FPE rate of about 0.012% (35/28,400) in patients receiving prophylactic anticoagulants can be attributed to 'rebound hypercoagulation' in the two months after stopping anticoagulants. Alternatives to anticoagulant prophylaxis should be explored.

METHODS AND FINDINGS

The literature concerning dietary influences on VTE incidence was reviewed. Hypotheses concerning the etiology of VTE were critiqued in relationship to the rationale for dietary versus anticoagulant approaches to prophylaxis and treatment.Epidemiological evidence suggests that a diet with ample fruits and vegetables and little meat may substantially reduce the risk of VTE; vegetarian, vegan, or Mediterranean diets favorably affect serum markers of hemostasis and inflammation. The valve cusp hypoxia hypothesis of DVT/VTE etiology is consistent with the development of VTE being affected directly or indirectly by diet. However, it is less consistent with the rationale of using anticoagulants as VTE prophylaxis. For both prophylaxis and treatment of VTE, we propose RCTs comparing standard anticoagulation with low VTE risk diets, and we discuss the statistical considerations for an example of such a trial.

CONCLUSIONS

Because of (a) the risks of biochemical anticoagulation as anti-VTE prophylaxis or treatment, (b) the lack of placebo-controlled efficacy data supporting anticoagulant treatment of VTE, (c) dramatically reduced hospital-acquired FPE incidence in surgical patients without anticoagulant prophylaxis from 1980 - 2010 relative to the 1960s and 1970s, and (d) evidence that VTE incidence and outcomes may be influenced by diet, randomized controlled non-inferiority clinical trials are proposed to compare standard anticoagulant treatment with potentially low VTE risk diets. We call upon the U. S. National Institutes of Health and the U.K. National Institute for Health and Clinical Excellence to design and fund those trials.