Coagulation factors, inflammation markers, and venous thromboembolism: the longitudinal investigation of thromboembolism etiology (LITE)

Implications of von Willebrand Factor in Inflammatory Bowel Diseases: Beyond Bleeding and Thrombosis

Inflammatory bowel disease (IBD) displays an increased venous and arterial thrombotic risk despite the common occurrence of intestinal bleeding. While some of the mechanisms leading to these thrombotic complications have been studied, other specific changes in the hemostasis profile of IBD patients have been less explored. One such example relates to von Willebrand factor (VWF) whose plasma levels have been reported to be modulated in IBD. Von Willebrand factor is a plasma glycoprotein crucial for hemostatic functions via roles both in platelet function and coagulation. High plasma VWF is a known risk factor for venous thromboembolism. In addition to its canonical roles in hemostasis, VWF is known to be directly or indirectly involved in other vascular processes such as maintenance of endothelial barrier integrity or proliferation of vascular smooth muscle cells. The purpose of this review is to recapitulate and update the existing data about VWF biology in IBD and to highlight its role both in the existing procoagulant phenotype and in vascular alterations that may occur in IBD.

Predictive modeling of deep vein thrombosis risk in hospitalized patients: A Q-learning enhanced feature selection model

Deep vein thrombosis (DVT) represents a critical health concern due to its potential to lead to pulmonary embolism, a life-threatening complication. Early identification and prediction of DVT are crucial to prevent thromboembolic events and implement timely prophylactic measures in high-risk individuals. This study aims to examine the risk determinants associated with acute lower extremity DVT in hospitalized individuals. Additionally, it introduces an innovative approach by integrating Q-learning augmented colony predation search ant colony optimizer (QL-CPSACO) into the analysis. This algorithm, then combined with support vector machines (SVM), forms a bQL-CPSACO-SVM feature selection model dedicated to crafting a clinical risk prognostication model for DVT. The effectiveness of the proposed algorithm's optimization and the model's accuracy are assessed through experiments utilizing the CEC 2017 benchmark functions and predictive analyses on the DVT dataset. The experimental results reveal that the proposed model achieves an outstanding accuracy of 95.90% in predicting DVT. Key parameters such as D-dimer, normal plasma prothrombin time, prothrombin percentage activity, age, previously documented DVT, leukocyte count, and thrombocyte count demonstrate significant value in the prognostication of DVT. The proposed method provides a basis for risk assessment at the time of patient admission and offers substantial guidance to physicians in making therapeutic decisions.

Effect of Three-Day Atorvastatin Administration on Coagulation Factors in Patients With Prior Venous Thromboembolism and Healthy Subjects: A Preliminary Study

ABSTRACT

Statins exert antithrombotic effects, which might contribute to reduced risk of venous thromboembolism (VTE). Rosuvastatin 20 mg/d administered for 4 weeks has been reported to decrease coagulation factors (F) VII, FVIII, and FXI in VTE patients. Moreover, in accordance with recent registry data in non-VTE subjects, statins usage was associated with lower FXI. We investigated whether 3 doses of a statin decrease coagulation factors activity and if such changes can alter fibrin clot properties in VTE patients and healthy subjects. We enrolled 28 consecutive first-ever prior VTE patients after 6 months of anticoagulation and 25 healthy controls well-matched for demographics and lipid profiles (aged 44 [interquartile range 34-51] years) in an interventional nonrandomized study. Before and after 3 doses of atorvastatin 40 mg/d, activity of FVII, FVIII, FIX, and FXI was measured, along with fibrin clot properties, including permeability (Ks) and clot lysis using 3 various assays. After a 3-day statin administration, we observed the decrease of FVII (by 6.2%, P = 0.046) and FXI (by 8.6%, P = 0.044), irrespective of low-density lipoprotein cholesterol reduction (by 24%, P < 0.001), whereas other coagulation factors remained unaltered. Reduction of FVII and FXI activity was inversely correlated with Ks alterations (R = -0.292, P = 0.034 and R = -0.335, P = 0.014, respectively). After adjustment for age, studied group, and fibrinogen level, the reduction of FXI was independently associated with an increase of fibrin clot permeability (B = -0.084, P = 0.027). In conclusion, a 3-day 40 mg atorvastatin administration is sufficient to reduce FVII and FXI activity in our pilot study, which is associated with favorable fibrin clot properties modification.

A study of recurrent life-threatening thrombosis accompanied with the duplication of the factor IX gene

Hereditary predisposition play an important role in thrombosis, especially in younger patients. Here we studied a young patient who experienced three different episodes of severe thromboses, some of which were life-threatening (pulmonary artery thrombosis, portal and mesenteric vein thrombosis, and arterial thrombosis of the lower leg). Blood levels of clotting related indicators were assessed. We screened 35 genes linked to thrombosis. We discovered a 756 kb duplication that spanned the F9 gene in region q27.1 of the X chromosome. The repeat includes the full F9 gene, thus, the patient had two functional copies of FIX with the FIX activity 192%. An identical repetition was found in the patient's mother. Both the patient and his mother had high, but variable, plasma FIX activities that promote coagulation. The patient's frequent, severe thrombolic events maybe attributed to the duplication of a big portion of the F9 gene and lupus anticoagulant positive.

Association of circulating proprotein convertase subtilisin/kexin type 9 concentration with coagulation abnormalities in patients with primary membranous nephropathy

OBJECTIVES

The aims of the study were to explore the potential associations between plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) and coagulation indexes in patients with primary membranous nephropathy (PMN).

METHODS

A total of 87 patients diagnosed with PMN were enrolled in our study. 30 healthy participants were recruited to match PMN participants. Plasma PCSK9 concentrations were tested by enzyme-linked immunosorbent assay (ELISA). Correlations between PCSK9 and coagulation abnormalities in patients with PMN were analyzed using univariate and multiple linear regression analysis.

RESULTS

Plasma PCSK9 levels in patients with PMN were significantly higher than that in healthy controls [232.0 (143.5, 359.5) ng/mL vs. 166.8 (129.7, 199.7) ng/mL; p = 0.001]. Plasma levels of PCSK9 were positively correlated with factor VIII, factor IX, factor XI, log-transformed tissue factor, protein C and protein S (r = 0.267, p = 0.013; r = 0.496, p < 0.001; r = 0.217, p = 0.045; r = 0.584, p < 0.001; r = 0.372, p = 0.001; r = 0.282, p = 0.011). In multiple linear regression analysis, PCSK9 concentration was independently and positively correlated with factor VIII, factor IX, and tissue factor (β = 0.186, p = 0.047; β = 0.325, p = 0.001; β = 0.531, p < 0.001; respectively). PCSK9 concentration was independently and negatively correlated with PT (β= -0.343, p = 0.011).

CONCLUSION

Plasma PCSK9 levels had good positive correlations with procoagulant clotting factors and negative correlations with PT in PMN, which might provide novel information with regard to PCSK9 and hypercoagulability in PMN.

Combined effect of high factor VIII levels and high mean platelet volume on the risk of future incident venous thromboembolism

BACKGROUND

High factor VIII (FVIII) levels and large platelets, as reflected by a high mean platelet volume (MPV), are separately associated with increased risk of venous thromboembolism (VTE). Whether the combination of high FVIII levels and large platelets has a supra-additive effect on VTE risk is unknown.

OBJECTIVES

We aimed to investigate the joint effect of high FVIII levels and large platelets, as reflected by high MPV, on the risk of future incident VTE.

METHODS

A population-based nested case-control study with 365 incident VTE cases and 710 controls was derived from the Tromsø study. FVIII antigen levels and MPV were measured in blood samples drawn at baseline. Odds ratios with 95% CIs were estimated across FVIII tertiles (<85%, 85%-108%, and ≥108%) and within predefined MPV strata (<8.5, 8.5-9.5, and ≥9.5 fL).

RESULTS

VTE risk increased linearly across FVIII tertiles (Ptrend < .001) in models adjusted for age, sex, body mass index, and C-reactive protein. In the combined analysis, participants with FVIII levels in the highest tertile and an MPV of ≥9.5 fL (ie, joint exposure) had an odds ratio for VTE of 2.71 (95% CI, 1.44-5.11) compared with those with FVIII levels in the lowest tertile and an MPV of <8.5 fL (reference). In the joint exposure group, 52% (95% CI, 17%-88%) of VTEs were attributable to the biological interaction between FVIII and MPV.

CONCLUSION

Our results suggest that large platelets, as reflected by high MPV, might play a role in the mechanism by which high FVIII level increases the risk of incident VTE.

Genetic Variants Identified by Whole Exome Sequencing in a Large Italian Family with High Plasma Levels of Factor VIII and Von Willebrand Factor

High plasma levels of factor VIII (FVIII) and von Willebrand factor (VWF) have been indicated as independent risk factors for venous thromboembolism. However, the genetic factors responsible for their increase remain poorly known. In a large Italian family with high FVIII/VWF levels and thrombotic episodes, whole exome sequencing (WES) was performed on 12 family members to identify variants/genes involved in FVIII/VWF increase. Twenty variants spread over a 8300 Kb region on chromosome 5 were identified in 12 genes, including the low frequency rs13158382, located upstream of the MIR143/145 genes, which might affect miR-143/145 transcription or processing. The expression of miR-143/145 and VWF mRNA were evaluated in the peripheral blood mononuclear cells of six family members. Members with the variant (n = 3) showed lower levels of both miRNAs and higher levels of VWF mRNA compared to members without the variant (n = 3). An analysis of genetic and expression data from a larger cohort of individuals from the 1000 Genomes and GEUVADIS project confirmed a statistically significant reduction (p-value = 0.023) in miR-143 in heterozygous (n = 35) compared to homozygous wild-type individuals (n = 386). This family-based study identified a new genetic variant potentially involved in VWF increase by affecting miR-143/145 expression.

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.

Comparison of coagulation parameters associated with fibrinogen concentrate and cryoprecipitate for treatment of bleeding in patients undergoing cytoreductive surgery for pseudomyxoma peritonei: Subanalysis from a randomized, controlled phase 2 study

Background and Aims

The FORMA-05 study compared the efficacy and safety of human fibrinogen concentrate (HFC) versus cryoprecipitate for hemostasis in bleeding patients undergoing cytoreductive surgery for pseudomyxoma peritonei (PMP). This subanalysis explores coagulation parameters in the FORMA-05 patients, with a focus on the seven patients who developed thromboembolic events (TEEs).

Methods

FORMA-05 was a prospective, randomized, controlled phase 2 study in which patients with predicted blood loss ≥2 L received HFC (4 g) or cryoprecipitate (two pools of five units), repeated as needed. Plasma fibrinogen, platelet count, factor (F) XIII, FVIII, von Willebrand Factor (VWF) antigen and ristocetin cofactor activity levels, EXTEM A20, FIBTEM A20, and endogenous thrombin potential (ETP) were measured perioperatively.

Results

Fibrinogen, platelet count, EXTEM and FIBTEM A20, FXIII, FVIII, VWF levels, and ETP were maintained throughout surgery in both the HFC group (N = 21) and the cryoprecipitate group (N = 23). Seven TEEs were observed in the cryoprecipitate group. The two patients developing deep vein thromboses (DVT) appeared to have a procoagulant status preoperatively, with distinctively higher fibrinogen level, FIBTEM A20, and platelet levels, all of which persisted perioperatively. The five patients developing pulmonary embolism (PE) had slightly higher VWF levels preoperatively, with a disproportionate increase intraoperatively (postcryoprecipitate administration) and postoperatively.

Conclusions

Patients treated with HFC versus cryoprecipitate showed broad overlaps in coagulation parameters. Patients with PE experienced a disproportionate VWF rise following cryoprecipitate administration, whereas patients developing DVT displayed a procoagulant status before and following surgery. Preoperative testing may allow these patients to be identified.

Association between inflammatory biomarkers and venous thromboembolism: a systematic review and meta-analysis

BACKGROUND

Venous thromboembolism (VTE) is a common thrombotic vascular disease that has a significant impact on people's well-being and quality of life. A plethora of clinical studies explore the relationship between inflammatory biomarkers and VTE but yield conflicting results. This article proposed to pool these studies to draw a more convincing conclusion.

METHODS

We searched several databases for studies before April 2023. Available data was processed using Stata software (version 15.0 SE) and R (version 4.1.2). This meta-analysis has been registered in PROSPERO (CRD42022321815). The VTE in this review encompassed pulmonary embolism, deep vein thrombosis, and cerebral venous thrombosis.

RESULTS

A total of 25 articles were finally involved in this study. Our results revealed that higher levels of high-sensitivity C-reactive protein (hs-CRP, MD, 0.63, 95%CI, 0.21-1.05) and C-reactive protein (CRP)> 3ug/ml (OR, 1.52, 95%CI, 1.18-1.96) might be regarded as risk factors for future VTE occurrence. The elevated levels of monocyte (MD, 0.03, 95%CI, 0.00-0.05), hs-CRP (0.85, 0.61-1.08), CRP (0.66, 0.20-1.13) and IL-6 (0.47, 0.25-0.70) might represent the previous VTE; a series of markers such as white blood cell (1.43, 0.88-1.98), neutrophil (1.79, 1.02-2.56), monocyte (0.17, 0.14-0.21), hs-CRP (3.72, 1.45-5.99), IL-6 (5.99, 4.52-7.46), platelet-lymphocyte ratio (33.1, 24.45-41.78) and neutrophil-lymphocyte ratio (1.34, 0.95-1.73) increased during the acute phase of VTE.

CONCLUSIONS

In general, activated inflammatory biomarkers might not only be correlated with an increased risk of VTE, but may also give a hint of the occurrence of VTE in clinical settings.

Elevated plasma complement factor H related 5 protein is associated with venous thromboembolism

Venous thromboembolism (VTE) is a common, multi-causal disease with potentially serious short- and long-term complications. In clinical practice, there is a need for improved plasma biomarker-based tools for VTE diagnosis and risk prediction. Here we show, using proteomics profiling to screen plasma from patients with suspected acute VTE, and several case-control studies for VTE, how Complement Factor H Related 5 protein (CFHR5), a regulator of the alternative pathway of complement activation, is a VTE-associated plasma biomarker. In plasma, higher CFHR5 levels are associated with increased thrombin generation potential and recombinant CFHR5 enhanced platelet activation in vitro. GWAS analysis of ~52,000 participants identifies six loci associated with CFHR5 plasma levels, but Mendelian randomization do not demonstrate causality between CFHR5 and VTE. Our results indicate an important role for the regulation of the alternative pathway of complement activation in VTE and that CFHR5 represents a potential diagnostic and/or risk predictive plasma biomarker.

Renal transplant and hemostasis: early postoperative changes in recipients and donors

Background

The benefit of administering pharmacologic thromboprophylaxis following renal transplantation remains uncertain.

Objectives

To compare hemostatic parameters before and after renal transplant surgery in both recipients and their donors at predetermined time points.

Methods

Blood samples were collected at baseline (T1), immediately after surgery (T2), and at 24 hours after surgery (T3) in both recipients and donors and at 72 (T4) and 120 hours (T5) from recipients only. Assays included in vitro thrombin generation, factor VIII (FVIIIc) activity, von Willebrand factor (VWF) antigen, D-dimer, antithrombin activity, prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin complexes, and plasminogen activator inhibitor-1 (PAI-1) antigen.

Results

Fifty-two patients (28 recipients and 24 donors) were enrolled. Both donors and recipients had increased FVIIIc, VWF, F1 + 2, D-dimer, and PAI immediately after surgery but reduced antithrombin. Mixed-model analysis showed that the magnitude of change over time (between T1 and T3) for FVIIIc (mean estimated difference [MED], 72; 95% CI, 41-102; P < .0001), VWF (MED, 89; 95% CI, 35-142; P = .001), F1 + 2 (MED, 283; 95% CI, 144-422; P < .0001), thrombin-antithrombin complexes (MED, 3.5; 95% CI, 1.9-5.1; P < .0001), D-dimer (MED, 2.2; 95% CI, 1.0-3.3; P < .0001), PAI-1 (MED, 9.2; 95% CI, 3.4-14.9; P = .002), and time to peak thrombin generation (MED, 1.5; 95% CI, 0.35-2.7; P = .01) was more significant in recipients than in donors.

Conclusion

Persistence of a hypercoagulable state was more prominent in recipients after 24 hours despite recovery in renal function and initiation of thromboprophylaxis.

Impact of the von Willebrand factor-ADAMTS-13 axis on the risk of future venous thromboembolism

BACKGROUND

von Willebrand factor (VWF) and its cleaving protease, ADAMTS-13, form a pivotal axis that regulates hemostasis. However, the role of the VWF-ADAMTS-13 axis in the risk of future venous thromboembolism (VTE) is unknown.

OBJECTIVES

To investigate whether plasma ADAMTS-13 levels and an imbalance with VWF levels, assessed as the VWF/ADAMTS-13 ratio, are associated with the risk of future VTE.

PATIENTS/METHODS

A population-based nested case-control study, comprising 383 incident VTE cases and 780 age- and sex-matched controls, was derived from the Tromsø study cohort (1994-2007). Antigen levels of ADAMTS-13 and VWF were measured in plasma samples obtained at cohort baseline. Odds ratios (ORs) with 95% CIs were estimated according to quartile cutoffs of ADAMTS-13 and VWF/ADAMTS-13 ratio determined in controls.

RESULTS

In age- and sex-adjusted analysis, ADAMTS-13 levels were inversely associated with the VTE risk, with an OR of 1.40 (95% CI, 0.99-1.99) for the lowest vs highest quartiles. The VWF/ADAMTS-13 ratio was linearly associated with the VTE risk (P for trend = .001), with an OR of 1.70 (95% CI, 1.19-2.43) for the highest vs lowest quartiles, and the association was particularly pronounced for unprovoked VTE (OR, 2.81; 95% CI, 1.65-4.81). The ORs were only slightly attenuated after additional adjustments for body mass index and C-reactive protein.

CONCLUSIONS

Lowered ADAMTS-13 levels and an imbalance between ADAMTS-13 and VWF levels, reflected by an increased VWF/ADAMTS-13 ratio, were associated with an increased risk of future VTE. Our findings suggest that the VWF-ADAMTS-13 axis is involved in the pathogenesis of VTE.

High levels of factor VIII activity in patients with acquired hemophilia A in remission are associated with unusually low coagulation potentials

BACKGROUND

Elevated factor VIII activity (FVIII:C) is often observed in patients with acquired hemophilia A (PwAHA) in remission. However, comprehensive coagulation potentials in this patient group remain to be investigated.

AIM

To evaluate comprehensive coagulation potentials in PwAHA.

METHODS

We investigated coagulation function in eleven PwAHA with high FVIII:C (> 150 IU/dL) using thrombin generation assay (TGA) and/or rotational thromboelastometry (ROTEM), and compared findings with results obtained from contrived samples generated by spiking recombinant FVIII.

RESULTS

The median FVIII:C and FVIII inhibitor titers during remission in enrolled PwAHA were 206 IU/dL and 0.44 BU/mL, respectively. In all patients, lag time and time to peak were either prolonged or normal compared to contrived samples corresponding to their FVIII:C. However, higher values of peak thrombin and endogenous thrombin potentials compared to contrived samples were observed in two patients. ROTEM parameters were within normal ranges in all cases. One patient (FVIII:C 171 IU/dL) developed venous thrombosis and pulmonary embolism, but TGA parameters showed low or normal coagulation potential compared to contrived samples corresponding to his FVIII:C.

CONCLUSION

PwAHA with high FVIII:C could exhibit lower coagulation potentials than those corresponding to their FVIII:C.

Preoperative risk factors for deep vein thrombosis in knee osteoarthritis patients undergoing total knee arthroplasty

BACKGROUND

To analyze the risk factors for preoperative deep vein thrombosis (DVT) in knee osteoarthritis (OA) patients undergoing total knee arthroplasty (TKA).

METHODS

In this retrospective study, a total of 584 knee OA patients undergoing TKA were enrolled. General information, medical records and preoperative laboratory examination results of the patients were collected. According to the results of Doppler ultrasonography for the lower extremities, the patients were divided into DVT group and non-DVT group. Univariate and multivariate logistic regression were used to identify independent risk factors for preoperative DVT in knee OA patients undergoing TKA.

RESULTS

The incidence of DVT before TKA was 6.85% (40 cases). The increase of ESR (Erythrocyte Sedimentation Rate), platelet crit, IL-6 (Interleukin-6), and PCT (Procalcitonin) were associated with the development of DVT before TKA. Factors as coronary heart disease (CHD), diabetes mellitus (DM), Chronic Kidney Disease (CKD), NLR (ratio of neutrophils to lymphocytes), lower limb venous blood stasis, the time from onset to admission, RBC, PLT were identified by multivariate logistic regression to be the independent risk factors for preoperative DVT in knee OA patients undergoing TKA.

CONCLUSIONS

DM, CKD, CHD, increased in ESR, IL-6 and PCT, blood stasis of the lower extremities, increased in PLT, platelet crit and the time from onset to admission, decreased in RBC, were high risk factors for preoperative DVT in knee OA patients undergoing TKA.

Association Between Platelet Indices and Preoperative Deep Vein Thrombosis in Elderly Patients Undergoing Total Joint Arthroplasty: A Retrospective Study

To investigate the association between platelet (PLT) indices and preoperative deep vein thrombosis (DVT) in elderly patients undergoing total joint arthroplasty (TJA). A total of 1391 patients were enrolled. We created receiver operator characteristic (ROC) curve using the ratio of PLT indices to DVT before TJA, divided the enrolled patients into groups based on the cut-off value, and then analyzed risk factors for DVT before TJA in the multivariate binary logistic regression analysis. Preoperative DVT occurred in 103 cases. Based on the ROC curve, we determined that the cut-off values for PLT, mean platelet volume (MPV), platelet distribution width (PDW), platelet large cell ratio (P-LCR), and plateletcrit (PCT) were 202 × 109/L, 11.4 fL, 13.2 fL, 34.6%, and 0.228%. And the areas under the curve were 0.606, 0.605, 0.617, 0.616, and 0.598. Multivariate binary regression analysis revealed that the risk of preoperative DVT in TJA patients with PLT≥202 × 109/L, MPV≤11.4 fL, PDW≤13.2 fL, P-LCR≤34.6%, and PCT≥0.228% increased by 2.32 (P < .001, 95% confidence interval [CI] [1.50-3.60]), 1.86 (P < .001, 95% CI [1.22-2.83]), 2.17 (P < .001, 95% CI [1.43-3.31]), 2.27 (P < .001, 95% CI [1.50-3.45]), and 1.76 times (P = .013, 95% CI [1.13-2.76]), respectively. Age, P < .001, odds ratio (OR) = 1.08, 95% CI [1.04-1.11]; corticosteroid use, P = .011, OR = 3.66, 95% CI [1.34-9.96]. We found that increased PLT count and PCT, decreased MPV, PDW, and P-LCR, old age, and corticosteroid use were independent risk factors for preoperative DVT in elderly TJA patients.

Thrombophilia and outcomes of venous thromboembolism in older patients

Background

Limited data exist on thrombophilic risk factors and clinical outcomes in the elderly with venous thromboembolism (VTE).

Objectives

To describe the prevalence of laboratory thrombophilic risk factors and their association with VTE recurrence or death in a cohort of elderly people with VTE.

Methods

In 240 patients aged ≥65 years with acute VTE without active cancer or an indication for extended anticoagulation, we performed laboratory thrombophilia testing 1 year after the index VTE. Recurrence or death was assessed during the 2-year follow-up.

Results

A total of 78% of patients had ≥1 laboratory thrombophilic risk factor(s). Elevated levels of von Willebrand factor, homocysteine, coagulant activity of factor VIII (FVIII:C), fibrinogen, FIX:C, and low antithrombin activity were the most prevalent risk factors (43%, 30%, 15%, 14%, 13%, and 11%, respectively). Additionally, 16.2% of patients experienced VTE recurrence and 5.8% of patients died. Patients with a von Willebrand factor of >182%, FVIII:C level >200%, homocysteine level >15μmol/L, or lupus anticoagulant had a significantly higher rate of recurrence than those without these risk factors (15.0 vs. 6.1 [P = .006], 23.5 vs. 8.2 [P = .01], 17.0 vs. 6.8 [P = .006], and 89.5 vs. 9.2 [P = .02] events per 100 patient-years, respectively). Furthermore, patients with a high fibrinogen level or hyperhomocysteinemia with a homocysteine level ≥30 μmol/L had significantly higher mortality than patients with normal levels (18.5 vs. 2.8 [P = .049] and 13.6 vs. 2 [P = .002] deaths per 100 patient-years, respectively). After adjustments for relevant confounders, these associations remained unchanged.

Conclusion

Laboratory thrombophilic risk factors are common in elderly people with VTE and allow for the identification of a population at the risk of worse clinical outcomes.

Contemporary Biomarkers in Pulmonary Embolism Diagnosis: Moving beyond D-Dimers

Pulmonary embolism (PE) is a rather common cardiovascular disorder constituting one of the major manifestations of venous thromboembolism (VTE). It is associated with high mortality and substantial recurrence rates, and its diagnosis may be challenging, especially in patients with respiratory comorbidities. Therefore, providing a prompt and accurate diagnosis for PE through developing highly sensitive and specific diagnostic algorithms would be of paramount importance. There is sound evidence supporting the use of biomarkers to enhance the diagnosis and predict the recurrence risk in patients with PE. Therefore, several novel biomarkers, such as factor VIII, Ischemia Modified Albumin, and fibrinogen, as well as several MicroRNAs and microparticles, have been investigated for the diagnosis of this clinical entity. The present review targets to comprehensively present the literature regarding the novel diagnostic biomarkers for PE, as well as to discuss the evidence for their use in daily routine.

C-reactive protein, immunothrombosis and venous thromboembolism

C-reactive protein (CRP) is a member of the highly conserved pentraxin superfamily of proteins and is often used in clinical practice as a marker of infection and inflammation. There is now increasing evidence that CRP is not only a marker of inflammation, but also that destabilized isoforms of CRP possess pro-inflammatory and pro-thrombotic properties. CRP circulates as a functionally inert pentameric form (pCRP), which relaxes its conformation to pCRP* after binding to phosphocholine-enriched membranes and then dissociates to monomeric CRP (mCRP). with the latter two being destabilized isoforms possessing highly pro-inflammatory features. pCRP* and mCRP have significant biological effects in regulating many of the aspects central to pathogenesis of atherothrombosis and venous thromboembolism (VTE), by directly activating platelets and triggering the classical complement pathway. Importantly, it is now well appreciated that VTE is a consequence of thromboinflammation. Accordingly, acute VTE is known to be associated with classical inflammatory responses and elevations of CRP, and indeed VTE risk is elevated in conditions associated with inflammation, such as inflammatory bowel disease, COVID-19 and sepsis. Although the clinical data regarding the utility of CRP as a biomarker in predicting VTE remains modest, and in some cases conflicting, the clinical utility of CRP appears to be improved in subsets of the population such as in predicting VTE recurrence, in cancer-associated thrombosis and in those with COVID-19. Therefore, given the known biological function of CRP in amplifying inflammation and tissue damage, this raises the prospect that CRP may play a role in promoting VTE formation in the context of concurrent inflammation. However, further investigation is required to unravel whether CRP plays a direct role in the pathogenesis of VTE, the utility of which will be in developing novel prophylactic or therapeutic strategies to target thromboinflammation.

Plasma lipopolysaccharide-binding protein is a biomarker for future venous thromboembolism: Results from discovery and validation studies

BACKGROUND

Effect-size underestimation impedes biomarker identification. Long follow-up time in prospective studies attenuates effect-size estimates for transient biomarkers, while disease category-specific biomarkers are affected by merging of categories. Venous thromboembolism (VTE) encompasses deep vein thrombosis (DVT) and pulmonary embolism (PE).

OBJECTIVES

(i) To re-analyze untargeted proteomic data to identify biomarker candidates for future VTE that differ between DVT and PE and are attenuated by extended time between sampling and VTE. (ii) To perform targeted candidate validation.

PATIENTS/METHODS

A VTE case-control discovery study and a nested case-control validation study were derived from the general population surveyed in 1994-95. Plasma was obtained at study enrollment, and VTE events were registered until 2007. Untargeted proteomic data were re-analyzed for candidate discovery. Lipopolysaccharide-binding protein (LBP) was validated by enzyme-linked immunosorbent assay.

RESULTS

Elevated LBP was discovered as a candidate DVT biomarker in women with less than 3 years between blood sampling and DVT. In the validation study, the odds ratio (OR) for DVT was 2.03 (95% confidence intervals [CI]: 1.53-2.74) per standard deviation (SD) increase in LBP for women with less than 3 years between blood sampling and DVT. Adjustment for age, body mass index, and C-reactive protein attenuated the OR to 1.79 (95% CI: 1.25-2.62) per SD. In the validation study, we observed an OR for VTE of 0.47 (95% CI: 0.28-0.77) for men in the 25^th to 50^th percentiles when compared to the lowest quartile.

CONCLUSIONS

We discovered and validated increased LBP as a predictive biomarker for DVT in women. We found an increased VTE risk for men in the lowest quartile of LBP.

Thrombosis risk assessment in patients with congenital thrombophilia during COVID - 19 infection

Background

Coagulation dysfunction represents a serious complication in patients during the COVID-19 infection, while fulminant thrombotic complications emerge as critical issues in individuals with severe COVID-19. In addition to a severe clinical presentation, comorbidities and age significantly contribute to the development of thrombotic complications in this disease. However, there is very little data on association of congenital thrombophilia and thrombotic events in the setting of COVID-19. Our study aimed to evaluate the risk of COVID-19 associated thrombosis in patients with congenital thrombophilia.

Methods

This prospective, case-control study included patients with confirmed COVID-19 infection, followed 6 months post-confirmation. The final outcome was a symptomatic thrombotic event. In total, 90 COVID-19 patients, 30 with known congenital thrombophilia and 60 patients without thrombophilia within the period July 2020–November 2021, were included in the study. Evaluation of hemostatic parameters including FVIII activity and D-dimer was performed for all patients at 1 month, 3 months and 6 months post-COVID-19 diagnosis.

Results

Symptomatic thrombotic events were observed in 7 out of 30 (23 %) COVID-19 patients with thrombophilia, and 12 out of 60 (20 %) without thrombophilia, P = 0.715. In addition, the two patient groups had comparable localization of thrombotic events, time to thrombotic event, effect of antithrombotic treatment and changes in FVIII activity, while D-dimer level were significantly increased in patients without thrombophilia.

Conclusion

Our findings suggest that patients with congenital thrombophilia, irrespective of their age, a mild clinical picture and absence of comorbidities, should receive anticoagulant prophylaxis, adjusted based on the specific genetic defect.

Pathophysiological Aspects of Aging in Venous Thromboembolism: An Update

The aim of this review is to highlight all the factors that associate venous thromboembolism (VTE) with aging. Elderly people are characterized by a higher incidence of thrombosis taking into account the co-existing comorbidities, complications and fatality that arise. Based on the Virchow triad, pathophysiological aspects of venous stasis, endothelium injury and hypercoagulability in elderly people (≥65 years) are described in detail. More precisely, venous wall structure, nitric oxide (NO) and endothelin-1 expression are impaired in this age group. Furthermore, an increase in high-molecular-weight kininogen (HMWK), prekallikrein, factors V, VII, VIII, IX and XI, clot lysis time (CLT) and von Willebrand factor (vWF) is observed. Age-dependent platelet dysfunction and changes in anticoagulant factors are also illustrated. A “low-grade inflammation stage” is delineated as a possible risk factor for thrombosis in the elderly. Consequently, clinical implications for frail elderly people related to diagnosis, treatment, bleeding danger and VTE recurrence emerge. We conclude that aging is an acquired thrombotic factor closely related to pathophysiological changes.

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.

Leukotriene receptor antagonism with montelukast as a possible therapeutic for venous thromboembolism prophylaxis: An observational study

BACKGROUND

Arachidonic acid (AA), which is metabolized via the cyclooxygenase (COX) and the lipoxygenase (LOX) pathways, was found to be associated with venous thromboembolism (VTE). Metabolites of the LOX pathway include cysteinyl (Cys) Leukotrienes (LT), potent proinflammatory mediators, which have also been implicated in cardiovascular disease.

OBJECTIVE

The purpose of this study was to examine if cysteinyl leukotriene receptor blockade by montelukast, lowers the risk of VTE.

METHODS

We conducted a retrospective cohort study examining VTE risk among COPD patients from the United States Department of Veterans Affairs. We use propensity score matching and Cox survival models to estimate the hazard ratio comparing montelukast exposure to non-exposure. Montelukast exposure was associated with a 15.9% reduction in risk of VTE compared to those unexposed (HR= 0.841; 95% CI= (0.758-0.934)).

CONCLUSION

The results of this study demonstrate that targeting LTs might be beneficial for VTE prophylaxis using the clinically available LT inhibitor, montelukast. Importantly, further research on LTs is warranted to fully understand and validate this relationship.

Blood Cells and Venous Thromboembolism Risk: A Two-Sample Mendelian Randomization Study

Background

Previous studies have shown that various cell indices are associated with a higher risk of venous thromboembolism (VTE), however, whether these findings reflect a causal relationship remains unclear. Therefore, we performed a two-sample Mendelian randomization (MR) analysis to assess the causal association of various blood cells with VTE risk.

Study Design and Methods

Summary statistics of genetic instruments representing cell indices for erythrocytes, leukocytes, and platelets were extracted from genome-wide association studies of European ancestry, by Two-Sample Mendelian Randomization. Inverse variance weighting (IVW) was used as the primary analytical method for MR. Sensitivity analyses were performed to detect horizontal pleiotropy and heterogeneity.

Results

Genetically predicted red blood cell distribution width, mean reticulocyte volume, and mean red blood cell volume were positively associated with VTE, with odds ratio (OR) of 1.002 [CI 1.000-1.003, P = 0.022), 1.003 (CI 1.001-1.004, P = 0.001, respectively)] and 1.001 (CI 1.000-1.002, P = 0.005). Genetically predicted monocyte count was negatively correlated with VTE, with OR = 0.998 (CI 0.996-0.999, P = 0.041).

Conclusion

Genetically liability to high- red blood cell distribution width, mean reticulocyte volume, mean red blood cell volume, and low monocyte count are associated with the higher risk of VTE. Targeting these factors might be a potential strategy to prevent VTE.

Diagnostic Value of Galectin-3 for Identifying Acute Pulmonary Embolism in the Emergency Department

BACKGROUND

Pulmonary embolism (PE) is a common disease associated with high mortality and morbidity. Diagnosing PE is challenging due to diverse clinical presentations and the lack of specific biomarkers.

OBJECTIVE

We hypothesized that plasma galectin-3 (Gal-3) levels might reflect the severity of acute PE and be useful for diagnostic assessment.

METHODS

In this prospective study, 150 patients (100 patients with PE and 50 control patients) were included. Patients were stratified into high-risk, medium-risk, and low-risk groups according to the Wells and revised Geneva scoring systems, and Gal-3 levels were compared among the groups. PE was diagnosed by means of computed tomography pulmonary angiography.

RESULTS

In this study, of the 100 PE patients included in the study, 69 patients recovered and were discharged and 31 patients died. Median Gal-3 value in the PE group was 27.0 ng/mL (range 11.5-35.0 ng/mL), whereas the median Gal-3 value in the control group was significantly lower at 8.8 ng/mL (range 1.0-21.0 ng/mL) (p < 0.001). When the Gal-3 values of the PE group and the control group were evaluated with the receiver operator characteristic curve, the area under the curve was calculated as 0.99 (95% confidence interval 0.979-1). At a Gal-3 cutoff value of 13.55 ng/mL, which was determined to be the most appropriate value for PE diagnosis, the sensitivity was 98% and the specificity was 92%.

CONCLUSIONS

A biomarker that rapidly and accurately diagnoses acute PE in the emergency department can be an extremely useful tool. We concluded that plasma Gal-3 levels can be regarded as a promising marker of acute PE.

The Clinical Utility of ABO and RHD Systems as Potential Indicators of Health Status, a Preliminary Study in Greek Population

Objective: The objective of this study is to further highlight the differences between different ABO blood groups and Rhesus types with health biomarkers. Methods: In total 150 active healthy blood donors participated in our study comprising of 80 males from 19–61 years and 70 females aged from 21 to 64. Participants carrying blood group A were 55 individuals, blood group B 32, blood group O 51, and blood group AB 12, RHD+ 132, and RHD- 18. All the volunteer regular blood donors were selected recognizing them as a healthy population excluding drug and supplements intake. Their blood samples were analyzed just before blood donation for biochemical, hematological, and antioxidant markers. Statistical computations were performed using the SPSS tool, specifically, the one-way ANOVA test, Chi-square statistics, and logistic regression were used as statistical models. Results: O blood donors presented better iron absorption and the worst lipid profile. Indeed, a significant trend of high atheromatic index values revealed an increased risk for hyperlipidemia, in contrast with blood group A presenting a better lipid profile with lower atheromatic index values. There was also a gender related association for blood group A compared with O that was further highlighted using binary logistic regression. Conclusion: In this study, a significant difference was observed among the ABO blood groups in several of the examined biochemical and hematological biomarkers. O blood group appeared different behavior in comparison to all the tested blood groups and furthermore the RHD-group presented a better lipid profile in comparison to the RHD+ group. In order to obtain a more comprehensive view of the correlation between the ABO blood group and biochemical markers, further studies are required.

The aging venous system: from varicosities to vascular cognitive impairment

Aging-induced pathological alterations of the circulatory system play a critical role in morbidity and mortality of older adults. While the importance of cellular and molecular mechanisms of arterial aging for increased cardiovascular risk in older adults is increasingly appreciated, aging processes of veins are much less studied and understood than those of arteries. In this review, age-related cellular and morphological alterations in the venous system are presented. Similarities and dissimilarities between arterial and venous aging are highlighted, and shared molecular mechanisms of arterial and venous aging are considered. The pathogenesis of venous diseases affecting older adults, including varicose veins, chronic venous insufficiency, and deep vein thrombosis, is discussed, and the potential contribution of venous pathologies to the onset of vascular cognitive impairment and neurodegenerative diseases is emphasized. It is our hope that a greater appreciation of the cellular and molecular processes of vascular aging will stimulate further investigation into strategies aimed at preventing or retarding age-related venous pathologies.

The Relationship Between Thrombo-Inflammatory Biomarkers and Cellular Indices of Inflammation in Lymphoma Patients

Introduction

Thrombo-inflammatory biomarkers play an important role in the pathogenesis of lymphoma. We aimed to characterize the interrelationship of thrombo-inflammatory biomarkers and blood cellular indices in lymphoma patients.

Materials and Methods

Ninety-eight lymphoma patient samples were collected from Lymphoma Center of Clinic of Hematology, University of Belgrade, Serbia. Normal controls (n = 50) represented plasma from healthy individuals. Plasminogen activator inhibitor (PAI-1), D-Dimer, factor XIII, C-reactive protein (CRP), microparticles (Mp), Von Willebrand factor (vWF), total protein S, urokinase-type plasminogen activator (uPA), tumor necrosis factor (TNFα), β2-glycoprotein I (β2GPI), and fibronectin levels were measured utilizing commercially-available ELISA methods. Thrombin generation profile (TGA) was measured using a fluorometric kinetic assay. Platelets, leukocytes, lymphocytes, and neutrophils were measured in conjunction with the complete blood profile.

Results

Statistically significant differences were noted in levels of PAI-1, D-Dimer, factor XIII, CRP, microparticles, vWF, uPA, TNFα, β2GPI, fibronectin, and TGA when compared to normal (all P values < .001). Platelet to leukocyte ratio (PLA) correlated to TNFα and fibronectin (R = −0.31 and −0.53, respectively) and the platelet to neutrophil ratio (PNR) correlated to factor XIII and β2GPI (R = 0.40 and 0.40, respectively).

Conclusion

Plasma samples from lymphoma patients demonstrated a significantly altered thrombo-inflammatory biomarker profile that has notable correlations to blood cellular indices.

Von Willebrand Disease: Current Status of Diagnosis and Management

Von Willebrand disease (VWD) is a common bleeding disorder, affecting male and female individuals equally, that often manifests in mucosal bleeding. VWD can be secondary to a quantitative (Type 1 and Type 3) or qualitative (Type 2) defects in Von Willebrand factor (VWF). Initial testing includes VWF antigen, as well as a platelet binding assay to differentiate between qualitative and quantitative defects. Further subtyping requires additional testing and is needed to ensure appropriate treatment. Desmopressin, antifibrinolytics, hormonal treatments for heavy menstrual bleeding, and VWF concentrates are commonly used in the treatment of VWD.

Effect of red blood cell transfusion on inflammation, endothelial cell activation and coagulation in the critically ill

Background and Objectives

Red blood cell (RBC) transfusion is a frequently applied intervention in an intensive care unit. However, transfusion is associated with adverse outcomes including organ failure and thrombo‐embolic events. Mechanisms of these effects are not known but may be related to activation of the endothelium or of the coagulation or inflammatory system. We hypothesized that a RBC transfusion in the critically ill would result in further activation of these systems.

Materials and Methods

In 74 non‐bleeding critically ill patients receiving one RBC unit, markers of inflammation, endothelial cell activation and coagulation were measured before transfusion, at 1 h after transfusion and 24 h after transfusion. The impact of disease severity of the recipient on these changes was assessed by comparing septic and non‐septic patients (according to sepsis‐3 definition) and by correlation of biomarkers with the sequential organ failure assessment (SOFA) score.

Results

Levels of von Willebrand Factor (vWF), soluble ICAM‐1, soluble thrombomodulin, fibrinogen and d‐dimer were already high at baseline, whereas ADAMTS13 levels were low. VWF levels increased significantly 24 h after RBC transfusion (median 478% (338–597) vs. 526% (395–623), p = 0.009). The other biomarkers did not change significantly. Post transfusion change was not dependent on the presence of sepsis and was not correlated with SOFA score.

Conclusion

RBC transfusion in critically ill patients was associated with an increase in circulating vWF levels, suggesting a further increase in activation of the endothelium, a finding that was independent of the presence of sepsis or organ injury level.

Hemostatic factors, inflammatory markers, and risk of incident venous thromboembolism: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Several hemostatic factors and inflammatory markers are associated with the risk of incident venous thromboembolism (VTE), however, most existing data are from case-control studies in Caucasian populations.

OBJECTIVES

We aimed to prospectively confirm previous findings and explore less studied biomarkers in relation to VTE risk in a multi-racial/multi-ethnic cohort.

METHODS

Circulating levels of factor VIII, fibrinogen, D-dimer, plasmin-antiplasmin complex (PAP), C-reactive protein (CRP), and interleukin-6 (IL-6) were measured at baseline (2000-2002) in 6706 participants of the Multi-Ethnic Study of Atherosclerosis. Incident VTE was identified using hospitalization discharge codes from baseline to December 31, 2015. Hazard ratios (HRs) of VTE were estimated in Cox regression models.

RESULTS

There were 227 events during a median of 14 years of follow-up. Compared with participants in the lowest quartile, the HRs for those above the 95th percentile and p for trend across categories were 3.50 (95% confidence interval [CI] 1.98-6.19; p < .001) for D-dimer, 1.49 (95% CI 0.84-2.63; p = .02) for factor VIII, 1.32 (95% CI 0.76-2.28; p = .99) for fibrinogen, 1.92 (95% CI 1.08-3.42; p = .15) for PAP, 1.68 (95% CI 0.81-3.48; p = .08) for CRP, and 2.55 (95% CI 1.15-5.66; p = .07) for IL-6, after adjustment for demographics and body mass index. For CRP and IL-6, follow-up was restricted to 10 years because of violations of the proportional hazards assumption. No significant interactions by age/ethnicity were observed.

CONCLUSIONS

We demonstrated a fairly novel association between PAP and risk of incident VTE, and contributed further prospective confirmation regarding the associations of D-dimer, factor VIII, and IL-6 with VTE.

Combined effects of plasma von Willebrand factor and platelet measures on the risk of incident venous thromboembolism

Plasma von Willebrand factor (VWF) and platelet reactivity are both risk factors for venous thromboembolism (VTE), and VWF can promote hemostasis by interaction with platelets. In this study, we explored the combined effects of plasma VWF and platelet measures on the risk of incident VTE. A population-based nested case-control study with 403 cases and 816 controls was derived from the Tromsø Study. VWF, platelet count and mean platelet volume (MPV) were measured in blood samples drawn at baseline. Odds ratios (ORs) with 95% confidence intervals (CIs) for VTE were estimated across VWF tertiles, within predefined MPV (<8.5, 8.5-9.5, ≥9.5 fL) and platelet count (<230, 230-299, ≥300·109 L-1) strata. Here, participants with VWF levels in the highest tertile and MPV ≥9.5 fL had an OR of 1.98 (95% CI 1.17-3.36) for VTE compared with those in the lowest VWF tertile and with MPV <8.5 fL in the age- and sex-adjusted model. In the joint exposure group, 48% (95% CI 15% to 96%) of VTEs were attributable to the biological interaction between VWF and MPV. Similarly, individuals with VWF in the highest tertile and platelet count ≥300·109 L-1 had an OR of 2.91 (95% CI 1.49-5.67) compared with those with VWF in the lowest tertile and platelet count <230, and 39% (95% CI -2% to 97%) of VTEs in the joint exposure group were explained by the interaction. Our results suggest that both platelet reactivity and platelet count interact biologically with high plasma VWF, resulting in an increased risk of incident VTE.

Plasma levels of growth differentiation factor 15 are associated with future risk of venous thromboembolism

Growth differentiation factor 15 (GDF-15), a marker of inflammation and oxidative stress, has emerged as a biomarker for arterial cardiovascular disease. However, the association between GDF-15 and venous thromboembolism (VTE) remains uncertain. We therefore investigated the association between plasma GDF-15 levels and future risk of incident VTE and explored the potential of a causal association using Mendelian randomization (MR). We conducted a population-based nested case-control study comprising 416 VTE patients and 848 age- and sex-matched controls derived from the Tromsø Study. Logistic regression was used to calculate odds ratios (ORs) for VTE across GDF-15 quartiles. For the MR, we used data from the International Network on Venous Thrombosis (INVENT) consortium to examine whether single nucleotide polymorphisms (SNPs) associated with GDF-15 levels with genome-wide significance were related to VTE. We found that the ORs for VTE increased across GDF-15 quartiles (Ptrend = .002). Participants with GDF-15 values in the highest quartile (≥358 pg/mL) had an OR for VTE of 2.05 (95% confidence interval, 1.37-3.08) compared with those with GDF-15 in the lowest quartile (<200 pg/mL) in the age- and sex-adjusted model. ORs remained essentially the same after further adjustment for body mass index, smoking, hormone therapy, physical activity, and C-reactive protein. Similar results were obtained for provoked/unprovoked events, deep vein thrombosis, and pulmonary embolism. GDF-15 levels, as predicted by the SNPs, were not associated with VTE in MR. Our results indicate that high GDF-15 levels are associated with increased risk of VTE, but MR suggests that this association is not causal.

Plasma levels of von Willebrand factor and future risk of incident venous thromboembolism

Several case-control studies have reported elevated plasma von Willebrand factor (VWF) levels in patients with venous thromboembolism (VTE) compared with controls. However, because few studies have investigated the association in a prospective design, it is unclear whether elevated plasma VWF is a risk factor or a consequence of the VTE event. Therefore, we aimed to investigate the prospective association between plasma VWF levels and risk of VTE, as well as to perform subgroup analyses of deep vein thrombosis (DVT) and pulmonary embolism. We established a population-based nested case-control study of 414 VTE cases and 843 age- and sex-matched controls based on the Tromsø study cohort (1994-2007). Blood samples were collected at cohort baseline (1994-1995). Odds ratios (ORs) with 95% confidence intervals (CIs) for VTE were estimated across quartiles of VWF levels. We found that the risk of VTE increased linearly across quartiles of VWF levels (P for trend = .023). Participants with VWF in the highest quartile had an OR of 1.45 (95% CI, 1.03-2.03) for VTE compared with those in the lowest quartile. The association was strongest for unprovoked VTE (OR, 2.74; 95% CI, 1.66-4.54) and unprovoked DVT in particular (OR, 6.73; 95% CI, 3.07-14.76). Further adjustment for body mass index, C-reactive protein, hypertension, estrogen use, and smoking had a modest effect on the risk estimates. To conclude, we found a dose-dependent relationship between plasma VWF levels and future risk of incident VTE, and unprovoked events in particular. Our findings suggest that VWF may represent a promising biomarker for future risk of incident VTE.

Incidence and Risk Factors for Venous Thromboembolism Following 2462 Major Abdomino-Pelvic Surgeries in Tertiary Hospital

Purpose

To determine the incidence and risk factor of postoperative venous thromboembolism (VTE) in Thai populations and to evaluate morbidity, mortality, bleeding complications and the benefit of thromboprophylaxis in real-world practice.

Patients and Methods

We performed a retrospective, single-center, cohort study of patients from all age groups who underwent elective open or laparoscopic major abdomino-pelvic surgery between January 2008 and December 2018 at Chulabhorn Hospital, Bangkok, Thailand. We collected general medical information and specific data based on items from the Caprini risk scoring system.

Results

A total of 2462 major abdomino-pelvic surgeries were included. The study population consisted of 742 males (30.1%) and 1720 females (69.9%) aged 54.59 ± 13.27 years. The incidence of VTE in Thai patients that underwent major abdominal surgery was 0.48%. The most frequent influencing factor for VTE was a history of pulmonary embolism, which increased the risk of VTE 98.28-fold, whereas a history of deep vein thrombosis increased the risk of VTE by 12.34-fold. Other factors influencing VTE development were obesity, anticoagulant use, postoperative chemotherapy, preoperative chemotherapy, endometrium cancer, tumor-node-metastasis (TNM) stage 4 and American College of Chest Physicians (ACCP) class 4. Protective factors included no history of VTE, laparoscopic surgery, TNM stage 0 and benign disease and BMI<30. VTE significantly increased mortality whereas following ACCP guideline reduced mortality.

Conclusion

Post-operative VTE incidence in Thai patients undergoing major abdomino-pelvic surgery was lower compared with Western patients. Factors influencing for VTE were history of VTE, anticoagulant use, postoperative chemotherapy, preoperative chemotherapy, endometrium cancer, TNM stage 4 and ACCP class 4. Following ACCP guideline reduced the incidence of mortality.

Inflammatory Biomarkers in the Short-Term Prognosis of Venous Thromboembolism: A Narrative Review

The relationship between inflammation and venous thrombosis is not well understood. An inflammatory response may be both the cause and consequence of venous thromboembolism (VTE). In fact, several risk factors of VTE modulate thrombosis through inflammatory markers. Acute pulmonary embolism (PE) is burdened by a remarkable mortality rate, up to 34% in severely ill patients presenting with hemodynamic instability. Initial mortality risk stratification is based on hemodynamic instability. Patients with a situation of hemodynamic stability require immediate further risk assessment based on clinical, imaging, and circulating biomarkers, as well as the presence of comorbidities. Some inflammatory biomarkers have shown potential usefulness in the risk stratification of patients with VTE, especially acute PE. C-reactive protein on admission is associated with 30-day mortality and bleeding in VTE patients. P-selectin is associated with right ventricle dysfunction in PE patients and might be associated with VTE recurrences and the extension of thrombosis. Tissue factor microparticles are associated with VTE recurrence in cancer-associated thrombosis. Other inflammatory biomarkers present scarce evidence (inflammatory cytokines, erythrocyte sedimentation rate, fibrinogen, leukocyte count). In this manuscript, we will review the prognostic role of different inflammatory biomarkers available both for clinical practice and research in VTE patients.

Procoagulant factor levels and risk of venous thrombosis in the elderly

Essentials Venous thrombosis (VT) risk and coagulation factor levels increase with age. We studied the association between levels of procoagulant factors and the risk of a first VT in the elderly. Higher levels of factors VIII, IX, and XI, but not prothrombin, were associated with the risk of VT. Similar risk patterns were observed for provoked and unprovoked VT and for deep vein thrombosis and pulmonary embolism separately. ABSTRACT: Background Venous thrombosis (VT) incidence increases markedly with age. Coagulation factors are also positively associated with age. Objective To study whether higher levels of coagulation factors II (prothrombin), VIII, IX, and XI are associated with risk of a first VT in the elderly. Methods Four hundred and one patients and 431 control subjects aged 70 and older were included in the Age and Thrombosis, Acquired and Genetic risk factors in the Elderly (AT-AGE) study. Blood was collected 1 year after the event in patients and in all control subjects for measurement of coagulation factors. To assess the risk of VT, odds ratios (ORs) were calculated after stratification of coagulation factors in quartiles and at the 90th percentile, adjusting for potential confounders (age, sex, body mass index, and study center). Results Mean age was 78 years (range: 70-100 years). The ORs of VT for factors in the top quartile compared with the lowest quartile were 4.5 (95% confidence interval [CI]:2.7-7.3) for factor VIII, 2.4 (95% CI:1.1-5.2) for factor IX, and 1.7 (95% CI:1.0-2.9) for factor XI. High prothrombin was not associated with an increased VT risk. There was no dose-response association between the number of high coagulation factors and VT risk. The population attributable risk (PAR) of VT was 37.6%, 23.3%, and 12.4% for factor VIII, IX, and XI, respectively. Conclusion In this study of the elderly, higher factors VIII, IX, and XI but not prothrombin, were positively associated with the risk of VT.

Ethnoracial variations in venous thrombosis: Implications for management, and a call to action

Despite decades of improvement in its diagnosis and management, venous thromboembolism (VTE) remains a significant cause of cardiovascular morbidity and mortality. Clinically relevant differences exist in the risk of symptomatic VTE among ethnoracial groups. Underlying these differences in rates of VTE are patterns of known genetic thrombophilias, which may also influence the risks of major bleeding related to vitamin K antagonists or direct oral anticoagulants. In addition, social factors, differential access to care, and disease awareness differ between ethnoracial groups, which contributes to disparities in VTE outcomes that include higher fatal events. The vast majority of participants included in clinical trials for the prevention and treatment of VTE have been White Caucasian, which limits our understanding of the differential impact of these agents in non-White ethnoracial groups. Increasing the participation in clinical trials of diverse ethnoracial groups should be a priority, especially those groups who are disproportionately affected by the burden of VTE, or possible bleeding complications when exposed to anticoagulants. Advocacy by patients, researchers, and regulatory bodies is crucial to ensure adequate enrolment of diverse ethnoracial groups in order to best inform clinical decisions to optimize VTE prevention and treatment for non-White populations.

Neutrophil-Lymphocyte Ratio as a Predictor of Venous Thromboembolism after Total Knee Replacement

Venous thromboembolism (VTE) is a potentially serious complication after total knee replacement (TKR), and recent guideline recommends thromboprophylaxis for VTE after TKR. The neutrophil-lymphocyte ratio (NLR) has emerged as a simple and new prognostic biomarker for several cardiovascular diseases. This study was performed to investigate the precise incidence of postoperative VTE and the role of NLR for predicting VTE in patients receiving thromboprophylaxis after TKR. We retrospectively enrolled 264 patients undergoing TKR who underwent routine screening enhanced pulmonary artery and lower extremity venography computed tomography (CT) scan within 7 postoperative days. Biochemical tests were performed within 2 weeks prior to surgery, and the NLR was defined as the absolute neutrophil count in peripheral blood divided by lymphocyte count. All patients received thromboprophylaxis with enoxaparin postoperatively. Of 264 patients, 102 (38.6%) were diagnosed with deep vein thrombosis (DVT) or pulmonary embolism on CT scan. Preoperative NLR was significantly higher in patients with postoperative VTE compared with that in patients without VTE (2.57 ± 1.59 vs. 2.11 ± 1.10, p = 0.011). Receiver operating characteristic curve analysis showed that a preoperative NLR of 1.90 was the best cutoff value for the prediction of postoperative VTE (sensitivity 57.8%, specificity 55.6%, and area under curve 0.589). In the multivariate analysis, a preoperative NLR ≥1.90 was a sole independent predictor of postoperative VTE (odds ratio: 1.95, 95% computed tomography: 1.16-3.31, p = 0.013). The present study shows a higher incidence of VTE (38.6%) after TKR in patients receiving thromboprophylaxis than that reported in previous studies. Furthermore, preoperative NLR was significantly higher in patients with postoperative VTE, and a high preoperative NLR (≥1.90) was an independent predictor of VTE after TKR. NLR measurement may be a simple and useful method for the prediction of VTE in patients undergoing TKR.

A Mendelian randomization of γ' and total fibrinogen levels in relation to venous thromboembolism and ischemic stroke

Fibrinogen is a key component of the coagulation cascade, and variation in its circulating levels may contribute to thrombotic diseases, such as venous thromboembolism (VTE) and ischemic stroke. Gamma prime (γ') fibrinogen is an isoform of fibrinogen that has anticoagulant properties. We applied 2-sample Mendelian randomization (MR) to estimate the causal effect of total circulating fibrinogen and its isoform, γ' fibrinogen, on risk of VTE and ischemic stroke subtypes using summary statistics from genome-wide association studies. Genetic instruments for γ' fibrinogen and total fibrinogen were selected, and the inverse-variance weighted MR approach was used to estimate causal effects in the main analysis, complemented by sensitivity analyses that are more robust to the inclusion of pleiotropic variants, including MR-Egger, weighted median MR, and weighted mode MR. The main inverse-variance weighted MR estimates based on a combination of 16 genetic instruments for γ' fibrinogen and 75 genetic instruments for total fibrinogen indicated a protective effect of higher γ' fibrinogen and higher total fibrinogen on VTE risk. There was also a protective effect of higher γ' fibrinogen levels on cardioembolic and large artery stroke risk. Effect estimates were consistent across sensitivity analyses. Our results provide evidence to support effects of genetically determined γ' fibrinogen on VTE and ischemic stroke risk. Further research is needed to explore mechanisms underlying these effects and their clinical applications.

ADAMTS13 activity, high VWF and FVIII levels in the pathogenesis of deep vein thrombosis

BACKGROUND

Deep vein thrombosis (DVT) is a common multi-factorial disease with a partially understood aetiology. Although the roles of high factor (F)VIII and von Willebrand factor (VWF) levels are recognized, that of ADAMTS13 is still unclear.

AIM

To assess the association between ADAMTS13 activity levels, VWF antigen (VWF:Ag) and FVIII coagulant activity (FVIII:C) levels and DVT.

MATERIALS AND METHODS

365 Italian DVT patients and 292 age- and sex-matched controls were considered. Plasma ADAMTS13 activity was measured using FRETS-VWF73 assay. VWF:Ag and FVIII:C were measured using immunoassay and one-stage clotting assay (ACL TOP analyzer), respectively. Quartile analyses were performed to evaluate the individual association between ADAMTS13 activity, VWF:Ag, FVIII:C and DVT. The combined effect of high VWF levels (> 4th quartile) and low ADAMTS13 levels (< 1st quartile) was evaluated using binary variables. All models were age- and sex-adjusted. Estimated risks were reported as Odds ratio (OR) with 95% confidence intervals (CI).

RESULTS

ADAMTS13 activity was lower in DVT patients (94% vs. 98% of controls). Patients with an ADAMTS13 activity <1st quartile (86%) showed a 1.6-fold increased risk of DVT (95%CI, 1.05-2.55). The combination of low ADAMTS13 activity and high VWF:Ag levels was associated with a 15-fold increased risk (95%CI, 7.80-33.80). VWF:Ag and FVIII:C were associated to DVT with a dose-response relationship.

CONCLUSIONS

ADAMTS13 activity < 86% was associated with a moderate risk of DVT. The co-presence of low ADAMTS13 activity and high VWF levels resulted in a strong synergistic effect on DVT risk. The association of VWF:Ag and FVIII:C with DVT was confirmed.

Association Between Hepatic Triglyceride Content and Coagulation Factors: The Netherlands Epidemiology of Obesity Study

OBJECTIVE

Whether hepatic triglyceride content (HTGC) contributes to hypercoagulability beyond total body fat (TBF) and visceral adipose tissue (VAT) is unclear. We, therefore, aimed to investigate the association between HTGC and coagulation factors (F)I (fibrinogen), VIII, IX, and XI while adjusting for TBF and VAT. Approach and Results: In this cross-sectional analysis of the NEO study (Netherlands Epidemiology of Obesity; n=6671), a random subset of participants underwent magnetic resonance imaging and magnetic resonance spectroscopy to assess VAT and HTGC (n=2580). We excluded participants without complete imaging and coagulation assessment, and with history of liver disease, venous thrombosis, or on anticoagulation. Mean differences in coagulation factor levels across HTGC quartiles were estimated by linear regression adjusted for age, sex, ethnicity, education, alcohol intake, physical activity, smoking, estrogen, and menopause, in addition to TBF and VAT. Among the 1946 participants included, median HTGC was 2.66% (interquartile range: 1.34%-6.27%). Coagulation factor levels increased dose-dependently across HTGC quartiles. Mean differences between the fourth and first quartiles were 14.7 mg/dL (95% CI, 2.1-27.2) for fibrinogen, 6.7 IU/dL (95% CI, 0.5-12.9) for FVIII, 26.1 IU/dL (95% CI, 22.4-29.8) for FIX, and 8.6 IU/dL (95% CI, 4.6-12.6) for FXI. With further adjustment for TBF and VAT, the dose-response association of HTGC with FIX persisted, whereas associations with other factors disappeared.

CONCLUSIONS

HTGC was associated with various coagulation factors, of which FIX remained associated with HTGC after adjustment for TBF and VAT. HTGC might contribute to venous thrombosis risk beyond total body and visceral fat through FIX levels.

Profile of natural anticoagulant, coagulant factor and anti-phospholipid antibody in critically ill COVID-19 patients

The outbreak of novel coronavirus disease 2019 (COVID-19) has now become a global pandemic. Coagulopathy has been reported widely in critically ill COVID-19 patients and was related to high mortality. However, the comprehensive coagulation profiles have not been examined and the underlying mechanism of the coagulopathy in COVID-19 patients is unclear. To study the coagulation profiles of routine hemostasis tests, natural anticoagulants, coagulant factors and antiphospholipid antibodies in critically ill COVID-19 patients. This single-center and cross-section study included 19 patients with COVID-19, who were admitted to intensive care unit (ICU) at Tongji hospital in Wuhan, China, from Feb 23 to Mar 3, 2020. Demographic data, laboratory parameters, treatments and clinical outcomes of the patients were collected and analyzed. The final date of follow-up was Mar 31, 2020. In this study, 12 thrombotic events occurred in 9 patients, including 4 cerebral infarctions, 7 acro-ischemia and 1 internal jugular vein thrombosis. The common abnormalities of routine coagulation tests included evelated D-Dimer level (100%), prolonged prothrombin time (73.7%) and hyperfibrinogenemia (73.7%). The median activities of natural anticoagulants including protein C, protein S and antithrombin were all below the normal range. Factor VIII activities were significantly above normal range (median value 307%, IQR 198–441) in all patients. Factor V and factor VII activities were significantly lower in near-terminal stage patients. Anti-phospholipid antibodies were present in 10 patients. Strikingly, 4 cerebral infarction events were in patients had anti-phospholipid antibodies of multiple isotypes. Sustained hypercoagulable status and thrombotic events were common in critically ill patients with COVID-19. The low activities of natural anticoagulants, elevated factor VIII level and the presence of antiphospholipid antibodies, together, may contribute to the etiopathology of coagulopathy in COVID-19 patients.

Predicting the Risk of Recurrent Venous Thromboembolism: Current Challenges and Future Opportunities

Acute venous thromboembolism (VTE) is a commonly diagnosed condition and requires treatment with anticoagulation to reduce the risk of embolisation as well as recurrent venous thrombotic events. In many cases, cessation of anticoagulation is associated with an unacceptably high risk of recurrent VTE, precipitating the use of indefinite anticoagulation. In contrast, however, continuing anticoagulation is associated with increased major bleeding events. As a consequence, it is essential to accurately predict the subgroup of patients who have the highest probability of experiencing recurrent VTE, so that treatment can be appropriately tailored to each individual. To this end, the development of clinical prediction models has aided in calculating the risk of recurrent thrombotic events; however, there are several limitations with regards to routine use for all patients with acute VTE. More recently, focus has shifted towards the utility of novel biomarkers in the understanding of disease pathogenesis as well as their application in predicting recurrent VTE. Below, we review the current strategies used to predict the development of recurrent VTE, with emphasis on the application of several promising novel biomarkers in this field.

From Classical Laboratory Parameters to Novel Biomarkers for the Diagnosis of Venous Thrombosis

Venous thrombosis is a common and potentially fatal disease, because of its high morbidity and mortality, especially in hospitalized patients. To establish the diagnosis of venous thrombosis, in the last years, a multi-modality approach that involves not only imaging modalities but also serology has been evolving. Multiple studies have demonstrated the use of some biomarkers, such as D-dimer, selectins, microparticles or inflammatory cytokines, for the diagnosis and treatment of venous thrombosis, but there is no single biomarker available to exclusively confirm the diagnosis of venous thrombosis. Considering the fact that there are some issues surrounding the management of patients with venous thrombosis and the duration of treatment, recent studies support the idea that these biomarkers may help guide the length of appropriate anticoagulation treatment, by identifying patients at high risk of recurrence. At the same time, biomarkers may help predict thrombus evolution, potentially identifying patients that would benefit from more aggressive therapies. This review focuses on classic and novel biomarkers currently under investigation, discussing their diagnostic performance and potential benefit in guiding the therapy for venous thrombosis.

Hematocrit and incidence of venous thromboembolism

BACKGROUND

Patients with polycythemia vera with high hematocrit have increased risk of venous thromboembolism (VTE).

OBJECTIVE

To determine whether high hematocrit in the general population is also associated with elevated VTE risk.

METHODS

The prospective Atherosclerosis Risk in Communities Study performed a complete blood count in 13 891 adults aged 45 to 64 in 1987 to 1989. We identified incident hospitalized VTEs through 2015 and performed proportional hazards regression analyses using race-sex-specific categorization of hematocrit percentiles (ie, <5th, 5th to <25th, 25th to <75th, 75th to <95th, and 95th-100th percentiles, with the 25th to <75th percentile serving as the reference).

RESULTS

Over a median follow-up of 26 years, 800 participants had an incident venous thrombosis of the leg and/or a pulmonary embolism. There was a nonlinear association of hematocrit with VTE incidence, with risk elevated 72% for participants above the 95th percentile of hematocrit compared with the reference. Specifically, hazard ratios (95% confidence intervals) of incident VTE were 1.27 (0.91-1.76), 1.06 (0.87-1.28), 1 (reference), 1.17 (0.98-1.40) and 1.72 (1.30-2.27) across the 5 hematocrit percentiles, adjusted for age, race, sex, body mass index, smoking status and pack-years, and other confounding variables. The association of high hematocrit with VTE was limited to provoked VTE, with little evidence for unprovoked VTE. Hemoglobin above the 95th percentile also was associated with an increased risk of VTE. In contrast, there were no significant associations of platelet, leukocyte, neutrophil, or lymphocyte counts with VTE incidence.

CONCLUSION

High hematocrit and hemoglobin in a general middle-aged population sample were associated with increased long-term risk of VTE, particularly provoked VTE.

Burden of rare exome sequence variants in PROC gene is associated with venous thromboembolism: a population-based study

BACKGROUND

Rare coding mutations underlying deficiencies of antithrombin and proteins C and S contribute to familial venous thromboembolism (VTE). It is uncertain whether rare variants play a role in the etiology of VTE in the general population.

OBJECTIVES

We conducted a deep whole-exome sequencing (WES) study to investigate the associations between rare coding variants and the risk of VTE in two population-based prospective cohorts.

PATIENTS/METHODS

Whole-exome sequencing was performed in the Longitudinal Investigation of Thromboembolism Etiology (LITE), which combines the Atherosclerosis Risk in Communities (ARIC) study (316 incident VTE events among 3159 African Americans [AAs] and 458 incident VTEs among 7772 European Americans [EAs]) and the Cardiovascular Healthy Study (CHS; 60 incident VTEs among 1751 EAs). We performed gene-based tests of rare variants (allele frequency < 1%, exome-wide significance P < 1.47 × 10-6 ) separately in each study and ancestry group, and meta-analyzed the results for the EAs in ARIC and CHS.

RESULTS

In the meta-analysis of EAs, we identified one gene, PROC, in which the burden of rare, coding variants was significantly associated with increased risk of VTE (HR = 5.42 [3.11, 9.42] for carriers versus non-carriers, P = 2.27 × 10-9 ). In ARIC EAs, carriers of the PROC rare variants had on average 0.75 standard deviation (SD) lower concentrations of plasma protein C and 0.28 SD higher D-dimer (P < .05) than non-carriers. Adjustment for low protein C status did not eliminate the association of PROC burden with VTE. In AAs, rare coding PROC variants were not associated with VTE.

CONCLUSIONS

Rare coding variants in PROC contribute to increased VTE risk in EAs in this general population sample.

Resting heart rate and incidence of venous thromboembolism

BACKGROUND/OBJECTIVES

Higher resting heart rate is a risk factor for arterial cardiovascular diseases. We assessed whether higher heart rate is a risk factor for venous thromboembolism (VTE).

METHODS

In a prospective epidemiologic cohort, the Atherosclerosis Risk in Communities (ARIC) Study, we associated resting heart rate by electrocardiogram with physician-validated incident hospitalized VTE through 2015. We also examined whether lower heart rate variability (HRV), a marker of cardiac autonomic imbalance, might be a risk factor for VTE.

RESULTS

Resting heart rate at Visit 1 (1987-1989), when participants were 45 to 64 years old (mean, 54 years), was not associated with incidence of VTE (n = 882 cases). However, heart rate at Visit 4 (1996-1998; mean age, 63 years) was associated positively with VTE (n = 557 cases). The adjusted hazard ratios (95% confidence intervals) of VTE across Visit 4 heart rate categories of <60, 60 to 69, 70 to 79, and ≥80 bpm were 1 (reference), 1.22 (1.01-1.49), 1.39 (1.09-1.78), and 1.44 (1.01-2.06), respectively, and when evaluated continuously 1.11 (1.02-1.21) per 10 bpm greater heart rate. For the most part, HRV indices were not associated with VTE or associations were explained by inverse correlations of HRV indices with heart rate.

CONCLUSION

We found a significant positive and independent association of resting heart rate at ARIC Visit 4 with incidence of VTE. The reason why high heart rate is a risk marker for VTE warrants further exploration.

Impact of respiratory symptoms and oxygen saturation on the risk of incident venous thromboembolism-the Tromsø study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is associated with risk of venous thromboembolism (VTE). It remains unknown whether individual respiratory symptoms and lowered oxygen saturation (SpO2), individually and in combination with COPD, affect the risk of VTE.

OBJECTIVES

To investigate whether measures of respiratory impairments including respiratory symptoms and SpO2, individually and combined with COPD, were associated with an increased risk of VTE.

METHODS

Spirometry, SpO2, and self-reported respiratory symptoms were collected in 8686 participants from the fifth (2001-2002) and sixth (2007-2008) surveys of the Tromsø Study. Incident VTE events were registered from the date of inclusion to December 31, 2016. Cox regression models with exposures and confounders as time-varying covariates (for repeated measurements) were used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) for VTE.

RESULTS

During a median follow-up of 9.1 years, 330 participants developed incident VTE. Subjects with SpO2 ≤ 96% (lowest 20th percentile) had a 1.5-fold higher risk of VTE (adjusted HR, 1.48; 95% CI, 1.13-1.93) compared with those with SpO2 ≥ 98%. Severe respiratory symptoms (dyspnea, cough, and phlegm) were associated with a 1.4- to 2.0-fold higher risk of VTE compared with no such symptoms. COPD, combined with respiratory symptoms or lowered SpO2, had an additive effect on the VTE risk.

CONCLUSIONS

Lowered SpO2 and severe respiratory symptoms were associated with increased VTE risk. COPD combined with respiratory impairments had an additive effect on VTE risk, and may suggest particular attention on VTE preventive strategies in COPD patients with respiratory impairments.