Risk factors of venous thromboembolism in thai patients

Factor VIII and Incident Hypertension in Black and White Adults: The REasons for Geographic and Racial Differences in Stroke (REGARDS) Cohort

BACKGROUND

Nearly half of all Americans have hypertension, and Black adults experience a disproportionate burden. Hypercoagulability may relate to hypertension risk, and higher levels of factor VIII increase thrombosis risk. Black adults have higher factor VIII and more hypertension than other groups. Whether higher factor VIII associates with incident hypertension is unknown.

METHODS

The Biomarkers as Mediators of Racial Disparities in Risk Factors (BioMedioR) study measured certain biomarkers in a sex-race stratified sample of 4,400 REGARDS participants who attended both visits. We included BioMedioR participants, excluding those with prevalent hypertension, missing factor VIII level, or covariates of interest. Modified Poisson regression estimated risk ratios (RR) for incident hypertension by higher log-transformed factor VIII level per SD (SD of log-transformed factor VIII, 0.33). Weighting was applied to take advantage of REGARDS sampling design.

RESULTS

Among the 1,814 participants included (55% female, 24% Black race), the median follow-up was 9.5 years and 35% (2,146/6,138) developed hypertension. Black participants had a higher median (IQR) factor VIII level (105.6%; 87.1%-126.9%) than White participants (95.6%; 79.8%-115.9%; P < 0.001). The age- and sex-adjusted Black-White hypertension RR was 1.45 (95% CI 1.28, 1.63). Higher factor VIII was not associated with more hypertension (final model RR 1.01; 95% CI 0.94, 1.07).

CONCLUSIONS

In a prospective study of Black and White adults without prevalent hypertension, factor VIII was not associated with greater hypertension risk.

Dural arteriovenous fistula involving superior petrosal sinus with petrosal venous drainage in association with cerebral venous thrombosis: Literature review and illustrative case

Background

Dural arteriovenous fistulas (DAVFs) involving superior petrosal sinus (SPS) and superior petrosal vein (SPV) are extremely rare. The pathogenesis of these fistulas remains unclear. We are illustrating 2 cases of DAVFs involving the superior petrosal sinus and veins associated with venous sinus thrombosis with a literature review.

Methods

We reviewed the literature using the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines focusing on DAVFs involving the SPS and/or SPV. Additionally, we searched for additional articles through the reference lists of the included studies.

Results

Our review yielded 20 articles from 1997 until 2022 involving 33 patients with 34 fistulas, including our 2 patients. The mean age was 55.1 ± 12.9 years (range 25-85), 54.5% were males (n = 18). The patients presented with hemorrhage in 36.4% (n = 12), and progressive myelopathy in 30.3% (n = 10). Most fistulas often had arterial supply from MMA, MHT, and/or OA. The fistulas had infratentorial drainage in 64.71% (n = 22), supratentorial drainage in 23.53% (n = 8), and both supra and infratentorial drainage in 11.76% (n = 4). In 27.3% (n = 9), cerebral venous thrombosis was mentioned or identified. Endovascular treatment was performed in 47.1% of cases (n = 16), surgery in 29.4% (n = 10), and combination of treatments in 23.5% (n = 8). A total of 30.3% (n = 10) of cases had incomplete recovery or poor result.

Conclusion

DAVFs involving the SPS and/or SPV are associated with aggressive natural history, requiring early diagnosis and prompt treatment, leading to good prognosis. These fistulas may be acquired in origin, probably secondary to cerebral venous thrombosis.

De novo formation of remote dural arteriovenous fistula following treated cavernous sinus dural arteriovenous fistula

Background

The development of new dural arteriovenous fistulas (DAVFs) at another location following endovascular treatment of cavernous sinus DAVFs (CSDAVFs) are extremely rare. Our aim is to review cases of de Novo DAVFs that occurred after treatment of CSDAVFs at our institution and those reported in the literature.

Methods

We reviewed all cases of CSDAVFs evaluated by 2 experienced neuroradiologists. A literature search was performed using the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines focusing on De Novo DAVFs following the endovascular treatment of cerebrovascular malformations. Addition articles were searched through the reference lists of the included articles.

Results

From June 2004 and September 2019., we identified 3 (2.5%) cases of De Novo DAVFs occurred after endovascular treatment or spontaneous obliteration of CSDAVFs from 119 treated CSDAVFs at our institute. Our review yielded 9 articles involving 12 patients with 15 de novo DAVFs, including our 3 patients. The mean age was 55.08 ± 12.9 years (range 43-69), 83.3% were females (n = 10). The new remote DAVFs occurred after endovascular treatment of CSDAVFs in 10 (83.3%) patients. The de novo DAVFs occurred following spontaneous complete regression in 2 (16.7%) patients. All de novo DAVFs developed after complete obliteration of treated CSDAVFs.

Conclusion

Sinus thrombosis and elevated venous pressure may play an important role in the pathogenesis of a de novo DAVF formation. In addition, thrombophilic abnormalities and the use of contraceptives may contribute to sinus thrombosis, leading to the development of the second remote DAVF after treatment of CSDAVFs.

Congenital thrombophilia in East-Asian venous thromboembolism population: a systematic review and meta-analysis

Background

Various inherited traits contribute to the overall risk of venous thromboembolism (VTE). In addition, the epidemiology of thrombophilia in the East-Asian VTE population remains unclear; thus, we aimed to assess the proportion of hereditary thrombophilia via a meta-analysis.

Methods

Publications from PubMed, EMBASE, web of science, and Cochrane before December 30, 2022, were searched. Studies from Japan, Korea, China, Hong Kong, Taiwan, Singapore, Thailand, Vietnam, Myanmar, and Cambodia were included. Congenital thrombophilia was described as diseases including protein C (PC) deficiency, protein S (PS) deficiency, antithrombin (AT) deficiency, factor (F)V Leiden (FVL), and prothrombin G20210A mutations. Studies were selected by 2 reviewers for methodological quality analysis. A random-effects model was used for the meta-analysis, assuming that estimated effects in the different studies are not identical.

Results

Forty-four studies involving 6453 patients from 7 counties/regions were included in the meta-analysis. The prevalence of PC, PS, and AT deficiencies were 7.1%, 8.3%, and 3.8%, respectively. Among 2924 patients from 22 studies, 5 patients were carriers of FVL mutation. Among 2196 patients from 10 studies, 2 patients were carriers of prothrombin G20210A mutation in a Thailand study.

Conclusion

The prevalence of PC, PS, and AT deficiencies was relatively high, while a much lower prevalence of FVL and prothrombin G20210A mutations were identified in East-Asian patients with VTE. Our data stress the relative higher prevalence of PC, PS, and AT deficiencies for thrombophilia in the East-Asian VTE population.

Thrombosis and anticoagulation: clinical issues of special importance to hematologists who practice in Asia

There are clinical issues of special importance and practice variation in the management of venous thromboembolism (VTE) and in the use of anticoagulants among hematologists who practice in Asia. In Asian-inherited thrombophilia, coagulation is disturbed due to loss-of-function mutations of protein S and protein C causing protein S and protein C deficiencies, whereas the gain-of-function factor V Leiden and prothrombin G20210A mutations are almost absent. Thrombophilia screening is not recommended in patients with VTE patients who have major provoking factors. However, it can be considered in unprovoked young patients with VTE who have a strong family history of VTE. Cancer is the most important acquired risk factor for VTE in Asians. Limited cancer screening at the initial presentation of unprovoked VTE is appropriate, especially in the elderly. Direct oral anticoagulants have been shown to have similar efficacy and reduce risk of major bleeding, including intracranial hemorrhage and bleeding requiring hospitalization, compared with warfarin. Most clinical trials evaluating therapies for treatment and prevention of VTE have included small numbers of Asian patients. Despite this lack of evidence, direct oral anticoagulants have been increasingly used in Asia for cancer-associated thrombosis. Individualized assessment of thrombotic and bleeding risks should be used for all hospitalized Asian patients when deciding on pharmacologic thromboprophylaxis. More research is needed to understand the factors that contribute to risks of VTE and anticoagulant-associated bleeding in Asian patients as these may differ from Western populations.

Correlation of Air Pollution and Prevalence of Acute Pulmonary Embolism in Northern Thailand

BACKGROUND

The relationship between the level of air pollution and acute pulmonary embolism (APE) has had inconsistent results.

OBJECTIVE

This study aimed to analyze the relationship between the high level of air pollution exposure and APE.

METHODS

A ten-year retrospective cohort, single-center study was performed on patients diagnosed with APE from October 2010 to December 2020. The association between air pollution and monthly APE case diagnosis was analyzed.

RESULTS

A total number of 696 patients was included. The effect of every 10 µg/m³ increment of particulate matters with an aerodynamic diameter < 10 µm (PM₁₀) on total monthly APE cases (unprovoked PE and provoked PE) was increased significantly at lag 4, 5 and 6 months with adjusted RR (95% CI) of 1.06 (1.01, 1.12), p = 0.011, 1.07 (1.01, 1.13), p = 0.021 and 1.06 (1.01, 1.12), p = 0.030, respectively. Adjusted RR for APE was significantly increased for PM₁₀ in the second tertile ((adjusted RR (95% CI) 1.76 (1.12, 2.77)), p = 0.014.

CONCLUSIONS

We conclude that PM₁₀ is associated with an increased prevalence of APE cases. The policy for tighter control of air pollution in our country is needed to reduce the impact of air pollutants on people's health.

Establishment of a new protein C detection system based on chromogenic substrate assay and its clinical diagnostic value for deep vein thrombosis

Background

Deficiency of protein C (PC) affects the balance between blood coagulation and fibrinolysis in the human body. Chromogenic‐based assay is recommended as the preferred screening method for detecting PC deficiency. We established a PC detection system based on the chromogenic substrate assay.

Methods

First, a kit for the determination of PC activity in plasma was elaborately developed and its reaction parameters on XL‐3200c were explored. Then, we evaluated its performance and collected specimens to compare the test results obtained with those of the Siemens detection system. Finally, the clinical diagnostic efficacy of this detection system for deep vein thrombosis (DVT) was assessed.

Results

Optimum conditions for PC detection were 0.25–0.1 U/ml protein C activator Protac^® and 2.5–1 mM Pefachrome^®PCa5297. The composition and concentration ranges of buffer substances and stabilizers in the kit were also explored. Satisfactory results were observed in performance evaluation. The test results of the newly built detection system were highly correlated with those of the Siemens detection system (R² = 0.9771 in the control group and R² = 0.9776 in the DVT group), and Bland‐Altman plots also showed high consistency between the two detection systems. In addition, the area under the curve (AUC) of the newly built PC detection system for DVT was 0.888, indicating this system could effectively improve the diagnostic sensitivity and specificity for DVT.

Conclusion

In this study, a sensitive, wide linear range and reliable PC activity detection system were established.

Epidemiology of Cancer-Associated Thrombosis in Asia: A Systematic Review

The epidemiology of cancer associated thrombosis (CAT) in Asia is less well-studied and differs from that in the western countries. Here, we systematically examine population based and hospital-based studies reported between 1995 and 2020 to understand the epidemiology of CAT in Asia. From population-based studies, the estimated incidence of VTE in cancer patients was 1.85–9.88 per 1,000 person-years. The incidence of CAT in Asia is significantly higher than non-cancer associated VTE in the general population and cancer is perhaps the most important risk factor for VTE. Hospital-based studies were heterogeneous in study designs and reveal a wide range of prevalence of VTE among cancer patients at 0.5–44.6% while the cancer prevalence rates among VTE patients ranged from 6.1 to 65.5%. The cancer sites most associated with VTE and risk factors were similar between Asian and Western studies. CAT has a major impact on the survival of patients with cancer in Asia, but thromboprophylaxis is not commonly practiced and validated risk assessment tools are lacking. This study highlights the urgent need for large multinational epidemiological studies in Asia to establish the true burden of CAT and to guide appropriate prevention strategies.

The association between pre-transfusion hemoglobin levels and thalassemia complications

OBJECTIVES

To evaluate any association between pre-transfusion hemoglobin (Hb) levels and thalassemia complications and to identify the Hb cutoff values to predict thalassemia complications.

METHODS

We performed a cross-sectional study in thalassemia patients who attended the Adult Hematology Clinic of the tertiary care University Hospital from October 2017 to October 2018. A point-biserial correlation was used to identify any association between Hb levels and thalassemia complications. A receiver operating characteristic (ROC) curve was used to identify the diagnostic ability of Hb levels to predict thalassemia complications and identify Hb cutoff values.

RESULTS

Out of the 102 patients, there were 53 transfusion dependent thalassemia (TDT) patients and 49 non-transfusion dependent thalassemia (NTDT) patients. In theTDT group, Hb levels showed a negative correlation with severe hepatic iron overload and hypogonadism. The cutoff Hb levels to predict severe hepatic iron overload and hypogonadism were ≤7.01 and 6.81 g/dL, respectively, at which points the area under the ROC curve (AUC) were 0.721 and 0.708, respectively. In the NTDTgroup, Hb levels were negatively correlated with hepatic iron overload, osteoporosis, and pulmonary hypertension. The cutoff values of Hb levels to predict hepatic iron overload, osteoporosis, and pulmonary hypertension were ≤8.24, 7.16, and 7.16 g/dL, respectively, at which points the AUC were 0.923, 0.715, and 0.725, respectively.

CONCLUSIONS

Lower Hb level was associated with more frequent complications in both TDT and NTDT patients. The Hb cutoff levels to predict these complications were identified.

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.

Coagulopathy associated with COVID-19 - Perspectives & Preventive strategies using a biological response modifier Glucan

Direct endothelial injury by viruses and dysregulation of clotting mechanisms due to cytokine storm are the major precipitating factors of mortality in COVID-19; both are attributed to a fundamental dysregulation of the immune system. While immune dysregulation can be attributed to several factors, the risk of associated thrombogenic disruption varies across individuals. This variation depends on several factors, such as comorbidities, including diabetes, hypertension, and cardiovascular diseases. When considering ethnic variations, the vulnerability of Caucasians, African Americans and Hispanics needs to be addressed before arriving at strategies to handle thromboembolic complications, which have been identified in recent reports as the leading causes of mortality in COVID-19. Although evaluation of D-dimer and prothrombin during admission is considered to predict prognosis and mortality, there are no preventive or prophylactic strategies before hospital admission. Herein, we present our perspectives on the effect of regular supplementation with the biological response modifier beta glucan based on its relevance to immune modulation. This effect is of paramount importance in decreasing the development of severe COVID-19 and reducing mortality against the background of coagulopathy, especially in vulnerable populations.

PROC Promoter Single Nucleotide Polymorphisms Associated With Low Protein C Activity But Not Increased Risk of Thromboembolism in Pediatric Population

Protein C (PC) deficiency, caused by mutations of the PROC gene, is a common inherited risk factor of thromboembolism (TE) among Thai people. This study aimed to investigate the association of 3 single nucleotide polymorphisms (SNPs; −1654 C/T, −1641 A/G, −1461A/T) at the PROC promoter region with PC activity and the risk of developing TE. A total of 216 patient s with TE, diagnosed at aged 0 to 20 years, and 102 healthy adults were enrolled. The SNPs were identified by Sanger sequencing. Protein C activity was measured using an automated functional clotting assay. Linear and logistic regression analyses were used to determine the association of SNPs with PC activity and the risk of TE. Patients and controls with homozygous TAA (119.6% ± 26.1%) and CGT haplotypes (102.7% ± 22.6%) had significantly lower PC activity than those with a homozygous CAA haplotype (140.4% ± 44.9%); P = .027 and .016, respectively. However, none of these haplotypes increased the risk of TE. This study suggested that the 3 PROC promoter SNPs were shown to be associated with lower PC activity but did not increase the risk of TE.

Incidence of cancer-associated thromboembolism in Japanese gastric and colorectal cancer patients receiving chemotherapy: a single-institutional retrospective cohort analysis (Sapporo CAT study)

OBJECTIVE

Few data regarding the incidence of cancer-associated thromboembolism (TE) are available for Asian populations. We investigated the incidence of TE (TEi) and its risk factors among gastric and colorectal cancer (GCC) patients received chemotherapy in a daily practice setting.

DESIGN

A retrospective cohort study.

SETTING

A single-institutional study that used data from Sapporo City General Hospital, Japan, on patients treated between January 2008 and May 2015.

PARTICIPANTS

Five hundred Japanese GCC patients who started chemotherapy from January 2008 to May 2015.

PRIMARY AND SECONDARY OUTCOME MEASURES

TE was diagnosed by reviewing all the reports of contrast-enhanced CT performed during the follow-up period. All types of thrombosis detected by CT or additional imaging tests, such as venous TE, arterial TE and cerebral infarction, were defined as TE. Medical records of all identified patients were reviewed and potential risk factors for TE, including clinicopathological backgrounds, were collected. We defined the following patients as 'active cancer'; patients with unresectable advanced GCC, cancer recurrence during or after completing adjuvant chemotherapy and/or presence of other malignant tumours.

RESULTS

Of the 500 patients, 70 patients (14.0%) developed TE during the follow-up period. TEi was 9.2% and 17.3% in GCC patients, 18.1% and 3.5% in active and non-active cancer patients, and 24.0% and 12.9% in multiple and single primary, respectively. Multivariate logistic regression analysis showed that colorectal cancer (CRC) (OR 2.371; 95% CI 1.328 to 4.233), active cancer (OR 7.593; 95% CI 2.950 to 19.543) and multiple primary (OR 2.527; 95% CI 1.189 to 5.370) were independently associated with TEi.

CONCLUSION

TEi was 14.0% among Japanese GCC patients received chemotherapy, and was significantly higher among patients with CRC, active cancer and multiple primary than among those with gastric cancer, non-active cancer and single primary, respectively.

TRIAL REGISTRATION NUMBER

UMIN000018912.

Compound heterozygous mutations identified in severe type I protein S deficiency impaired the secretion of protein S

AIMS

Hereditary protein S (PS) deficiency is one of the natural anticoagulant deficiencies causing thrombophilia. We herein described a young male with recurrent deep venous thrombosis, who was diagnosed as type I PS deficiency with compound heterozygous mutations of PROS1 gene. We aimed to analyse the relationship between the genotype and phenotype detection and investigate the pathological mechanisms of PROS1 mutations causing PS deficiency.

METHODS

Genetic analysis of PROS1 gene was carried out by direct sequencing. Thrombin generation potential and the inhibition function of thrombin generation by plasma PS were detected by thrombin generation test (TGT). The mRNA transcription level of mutant PS in vitro was measured by real-time PCR, while the protein level was evaluated by western blot and ELISA. Cellular distribution of the protein was further analysed by immunofluorescence.

RESULTS

Compound heterozygous mutations (PROS1 c.1551_1552delinsG, p.Thr518Argfs*39 and PROS1 c.1681C>T, p.Arg561Trp) were identified in the propositus, and the former one was a novel small indel mutation. TGT results showed impaired inhibition of thrombin generation with the addition of activated protein C in his parents with certain heterozygous mutations. In vitro expression study, p.Thr518Argfs*39 mutant produced truncated protein retained in the cytoplasm, while p.Arg561Trp mutant partially affected the secretion of PS. Both mutations are located in C-terminal sex hormone-binding globulin (SHBG)-like domain of PS.

CONCLUSIONS

Compound heterozygous mutations identified in the study have strong detrimental effect, causing severe type I PS deficiency in the propositus. SHBG-like domain of PS might play an important role in PS secretion system.

Risk factors for venous thromboembolism (VTE) recurrences in Thai patients without cancer

INTRODUCTION

Studies in Western countries show that VTE recurrent rates are lower in the presence of a transient provoking factor, older age, female sex and/or hormonal use, while thrombophilia (factor V Leiden or prothrombin mutation) has no predictive role. This study aimed to determine the incidence and risk factors of recurrent VTE in Asian patients.

METHOD

This is a retrospective cohort study in adult VTE patients who were diagnosed during 2004-2014, had no active cancer and followed-up for at least 1 year.

RESULTS

There were 198 patients. The mean age was 58.2 ± 17.6 years and 68.2% were female. The diagnoses were deep vein thrombosis (56%), pulmonary embolism (32%) or both (12%). They were provoked by major surgery in 21.7%. Thrombophilia (antiphospholipid syndrome or protein C or protein S deficiency) was found in 11.6%. The recurrent rate during the median follow-up time of 52 months was 2.2 (95% confidence interval [CI] 1.46-3.31) per 100 patient-years. Presence of thrombophilia was independently associated with recurrences with the adjusted hazard ratio (aHR) of 3.52 (95% CI 1.32-9.42, p = 0.01). There were 144 patients who discontinued anticoagulants. During the median time of 55 months after stopping anticoagulants, the recurrent rate was 4.3 per 100 patient-years. Thrombophilia was associated with recurrences with aHR of 4.00 (95% CI 1.42-11.31, p = 0.01), while male sex, younger age, provoking conditions and hormone use showed no significant association.

CONCLUSION

VTE recurrent rate in Asians is comparable to Caucasians, but thrombophilia is the strongest risk factor.

Can thrombophilia predict recurrent catheter-related deep vein thrombosis in children?

Thrombophilia was not predictive of recurrent catheter-related deep vein thrombosis in children. Young age at the time of catheter insertion and lack of administration of anticoagulation were predictive of recurrent events.

Venous thromboembolism in Asia – an unrecognised and under-treated problem?

Venous thromboembolism (VTE) has been perceived for a long time to be less common in Asian populations, particularly in the Far East, than in Western populations. Generally, thromboprophylaxis is not implemented as frequently as it should be in high-risk patients. However, recent prospective studies undertaken in Asian countries have demonstrated higher rates of VTE after major surgery and in medical wards, approaching those observed in Western populations. Risk factors for VTE are not different in Asian patients from those of Western patients with the exception of thrombophilic mutations. Deficiencies of the natural anticoagulants (protein S, protein C, and antithrombin) are the predominant thrombophilias in Asia whereas factor V Leiden and prothrombin G20210A gene mutation are not found or rarely reported. Further large well-designed clinical studies are needed to evaluate the magnitude of the risk of VTE and the appropriate use of thromboprophylaxis in different clinical situations.

Justification of routine venous thromboembolism prophylaxis in head and neck cancer reconstructive surgery

BACKGROUND

Venous thromboembolism (VTE) is a preventable complication in which early ambulation is expected after head and neck surgery. Thus, the role of VTE prophylaxis is questionable and needs further assessment. The purpose of this study was to specify the relative contributing risk factors for patients who underwent head and neck cancer ablation with immediate reconstruction.

METHODS

A retrospective analysis was conducted of consecutive head and neck cancer ablations with immediate reconstructions between 2008 and 2013. Dextran and prostaglandin E2 (PGE2) were routinely given as flap thromboprophylaxis. Logistic regression was applied to analyze the potentially significant risk factors.

RESULTS

Of 1953 subjects, the incidence of symptomatic VTE was 2.2% with 0.1% mortality rate. Prolonged surgery (>592.5 minutes; P = .048), immobilization (>4 days; P = .019), and subjects without postoperative flap thromboprophylaxis (P = .002) are significant risk factors for VTE development.

CONCLUSION

Our flap thromboprophylaxis regime might have played a crucial role in keeping the incidence of VTE low. Despite prolonged immobilization in fibula flap reconstruction, the incidence of VTE remained low when flap thromboprophylaxis was given.

Recurrent mutations in a SERPINC1 hotspot associate with venous thrombosis without apparent antithrombin deficiency

Despite the essential anticoagulant function of antithrombin and the high risk of thrombosis associated with its deficiency, the prevalence of antithrombin deficiency among patients with venous thromboembolism (VTE) is very low. However, increasing evidence suggests that antithrombin deficiency may be underestimated. The analysis of SERPINC1, the gene encoding antithrombin, in 1,304 consecutive Chinese VTE patients and 1,334 healthy controls revealed a hotspot involving residues 294 and 295 that severely increases the risk of VTE. We detected the c.883G>A (p.Val295Met) (rs201381904) mutation in 11 patients and just one control (OR = 13.6; 95% CI: 1.7-107.1); c.881G>T (p.Arg294Leu) (rs587776397) in six patients but no controls; and c.880C>T (p.Arg294Cys) (rs747142328) in two patients but no controls. In addition, c.881G>A (p.Arg294His) (rs587776397) was identified in one control. These mutations were absent in a Caucasian cohort. Carriers of these mutations had normal antithrombin levels and anticoagulant activity, consistent with results obtained in a recombinant model. However, mutation carriers had a significantly increased endogenous thrombin potential. Our results suggest the existence in the Chinese population of a hotspot in SERPINC1 that significantly increases the risk of VTE by impairing the anticoagulant capacity of the hemostatic system. This effect is not revealed by current antigen or in vitro functional antithrombin assays.

Clinical characteristics, risk factors, and outcomes of usual and unusual site venous thromboembolism

: The primary objective was to demonstrate the different risk factors among patients presenting with usual and unusual site venous thromboembolism (VTE). The secondary objectives were to compare clinical characteristics and outcomes in each group. This was a retrospective observational cohort study. Patients admitted in Chiang Mai University Hospital who were diagnosed with VTE during January 2010 through December 2012 were included and classified into two groups: the usual and unusual site VTE. The usual sites of VTE included pulmonary embolism and lower extremity deep vein thrombosis. Clinical characteristics, risk factors, treatment, recurrence, bleeding rates, and deaths were collected. There were 165 patients included in the study, 82 in usual site group and 83 in unusual site group. Patients in usual site group were older than unusual site group (mean 58 vs. 50 years, P = 0.003) and were more symptomatic (89 vs. 49.4%, P < 0.001). The higher proportion of patients in usual site group had prolonged immobilization (22.0 vs. 2.4%, P < 0.001), prior surgery (12.2 vs. 1.2%, P = 0.005), and a history of chemotherapy (25.6 vs. 3.6%, P < 0.001). Local inflammation was significantly more common in unusual site group (0 vs. 8.5%, P < 0.001). The recurrent VTE and major bleeding rates were not statistically different between groups. The 3-year mortality rate was significantly higher in usual site VTE group (73.1 vs. 57.8%, P = 0.049). The study revealed the different risk factors and clinical characteristics between usual and unusual VTE sites.

R147W in PROC Gene Is a Risk Factor of Thromboembolism in Thai Children

The p.R147W mutation, the c.C6152T in exon 7, causing a change in amino acid from arginine to tryptophan of the PROC gene has been reported as a common mutation in Taiwanese populations with venous thromboembolism (VTE). The present study aimed to identify the prevalence of p.R147W in the Thai population and children with TE and the risk of developing TE. Patients aged ≤18 years diagnosed with TE were enrolled. The PROC gene was amplified by polymerase chain reaction using a specific primer in exon 7. The restriction fragment length polymorphism was designed using MwoI restriction enzyme. A total of 184 patients and 690 controls were enrolled. The most common diagnosis of TE was arterial ischemic stroke (AIS), at 100 (54.3%), followed by VTE, at 38 (20.6%), and cerebral venous sinus thrombosis (CVST), at 23 (12.5%). The prevalence of heterozygous and homozygous p.R147W in patients and controls was 9.5% versus 5.8% and 2.7% versus 0.1%, respectively. Heterozygous p.R147W had odds ratios (ORs) of 1.8 (95% confidence interval [CI]: 1.0-3.2, P = .04), 3.2 (95% CI: 1.2-8.2, P = .009), and 4.5 (95% CI: 1.6-12.8, P = .002) of developing overall TE, VTE, and CVST, respectively. Homozygous p.R147W had ORs of 20.2 (95% CI: 2.3-173.7, P < .001), 21.4 (95% CI: 2.2-207.9, P < .001), and 43.3 (95% CI: 3.8-490.6, P < .001) of developing overall TE, AIS, and CVST, respectively. This study suggested that p.R147W is a common mutation and increased risk of TE in Thai children.

Long-Term Effects of Unprovoked Venous Thromboembolism on Mortality and Major Cardiovascular Events

Background

Patients with unprovoked venous thromboembolism (VTE) are at an increased risk of mortality, but whether their cardiovascular risks also increase remains to be determined. We aimed to investigate the factors associated with overall mortality and major adverse cardiovascular events in patients with unprovoked VTE.

Methods and Results

We identified 2154 patients newly diagnosed with unprovoked VTE from Taiwan's National Health Insurance Database between 2000 and 2013, excluding those with reversible etiologies, underlying cancer, or autoimmune diseases. These patients with VTE were compared with an age‐, sex‐, and cardiovascular risk‐matched cohort of 4308 controls. The risk of mortality and major adverse cardiovascular events in patients with VTE was 2.23 (CI, 1.93–2.57; P<0.0001) and 1.86 (CI, 1.65–2.09; P<0.0001) times, respectively, higher than that of the conditions in controls. These events mostly occurred during the first year after the diagnosis of unprovoked VTE. Among patients with VTE, advanced age, male sex, and comorbid diabetes mellitus indicated a higher incidence of mortality and major adverse cardiovascular events. Conversely, comorbid hyperlipidemia attenuated these risks.

Conclusions

This nation‐wide cohort study revealed that patients with unprovoked VTE, particularly older males with diabetes mellitus, had an elevated risk of both mortality and cardiovascular events. Risk of mortality and major adverse cardiovascular events were highest within the first year after diagnosis and persisted during the 10 years of follow‐up.

Cancer-associated thrombosis in Asia

Thrombosis is a common complication in cancer patients. Although the major inherited risk factors for thrombophilia are different between Asians and Caucasians, the main acquired risk factors that are associated with the development of venous thromboembolism (VTE) in Asians appear to be similar to those for Caucasians. Malignancy is the most important acquired risk factor for VTE in Asians. Recent studies have shown that the incidence of VTE is significant in Asian patients with cancer, particularly those in an advanced stage. Cancer associated VTE is more severe and associated with higher morbidity and mortality. Unprovoked VTE is associated with an increased risk of subsequent cancer diagnosis. A number of international and national guidelines are available to provide guidance to healthcare providers to treat and prevent this serious complication based on best-available evidence. Identifying cancer patients at risk for VTE and use of appropriate thromboprophylaxis in these patients can potentially improve morbidity and mortality. Although direct oral anticoagulants (DOACs) may become an attractive treatment for cancer-associated VTE, further clinical trials are needed to evaluate the safety and efficacy of DOACs directly against LMWH in cancer patients.

Genetic Risk Factors of Venous Thromboembolism in the East Algerian Population

Many genetic risk factors have been identified for causing venous thromboembolism (VTE). Most of them affect the function of natural anticoagulant pathways, particularly the protein C system, although recent studies suggest a role of components of the hematopoietic pathway in the etiology of venous thrombosis. In this case–control study, we aimed to determine the frequency of prothrombin G20210A and factor V Leiden (FVL) G1691A polymorphisms and protein C, protein S, and antithrombin III deficiencies in the East Algerian population and to investigate whether these genetic factors are associated with VTE. On the other hand, our study tends to evaluate the status of JAK2V617F and calreticulin (CALR) mutations among these cases. The participants consisted of 121 cases with VTE and 146 healthy controls. Polymorphisms of FVL G1691A and prothrombin G20210A were genotyped by polymerase chain reaction (PCR) restriction fragment length polymorphism. JAK2-V617F and calreticulin mutations were analyzed by quantitative PCR and PCR followed by capillary electrophoresis sequencing, respectively. Protein C, protein S, and antithrombin levels were determined and then hereditary deficiencies were identified. Of all cases and controls, none was a carrier of the antithrombin III deficiency, prothrombin gene G20210A, and CALR mutations. Only 1 case reported having a positive JAK2 mutation (mutant allele burden was 15%). The FVL mutation (GA/AA) was found in 14 (11.6%) cases and 2 (1.4%) controls and it was significantly different between both the groups ( P = .001). Deficiencies of protein S and protein C were detected in 17 (18.8%) cases. The univariate analysis resulted in a significant impact of FVL (odds ratio [OR] = 9.4, 95% confidence interval [CI] = 2.1-42.3; P = .003) and of protein S deficiency (OR = 16.9, 95% CI =2.1-132.8, P = .007) on the VTE status. Both factors stayed significant after adjustment for sex and age. The OR of the protein C deficiency was slightly elevated (OR = 6.4, 95% CI = 0.7-55.5), but it did not reach the level of statistical significance ( P = .091), and it was therefore not considered as a risk factor. In conclusion, coagulant factor V gene G1691A mutation and protein S deficiency constitute important genetic risk factors in patients with VTE in Eastern Algeria. The somatic mutation of JAK2 V617F and CALR mutations are less frequent causes of VTE, thus routine testing for these mutations is not recommended.

Prevalence and Risk Factors for Complications in Patients with Nontransfusion Dependent Alpha- and Beta-Thalassemia

Background. Nontransfusion dependent thalassemia (NTDT) is a milder form of thalassemia that does not require regular transfusion. It is associated with many complications, which differ from that found in transfusion-dependent thalassemia (TDT). Currently available information is mostly derived from beta-NTDT; consequently, more data is needed to describe complications found in the alpha-NTDT form of this disease. Methods. We retrospectively reviewed the medical records of NTDT patients from January 2012 to December 2013. Complications related to thalassemia were reviewed and compared. Results. One hundred patients included 60 females with a median age of 38 years. The majority (54 patients) had alpha-thalassemia. Overall, 83 patients had one or more complications. The three most common complications were cholelithiasis (35%), abnormal liver function (29%), and extramedullary hematopoiesis (EMH) (25%). EMH, cardiomyopathy, cholelithiasis, and pulmonary hypertension were more commonly seen in beta-thalassemia. Osteoporosis was the only complication that was more common in alpha-thalassemia. The risk factors significantly related to EMH were beta-thalassemia type and hemoglobin < 8 g/dL. The risk factors related to osteoporosis were female gender and age > 40 years. Iron overload (ferritin > 800 ng/mL) was the only risk factor for abnormal liver function. Conclusion. The prevalence of alpha-NTDT complications was lower and different from beta-thalassemia.

Ethnic diversity in the genetics of venous thromboembolism

Genetic susceptibility is considered as a crucial factor for the development of venous thromboembolism (VTE). Epidemiologic and genetic studies have revealed clear disparities in the incidence of VTE and the distribution of genetic factors for VTE in populations stratified by ethnicity worldwide. While gain-of-function polymorphisms in the procoagulant genes are common inherited factors in European-origin populations, the most prevalent molecular basis for venous thrombosis in Asians is confirmed to be dysfunctional variants in the anticoagulant genes. With the breakthrough of genomic technologies, a set of novel common alleles and rare mutations associated with VTE have also been identified, in different ethnic groups. Several putative pathways contributing to the pathogenesis of thrombophilia in populations of African-ancestry are largely unknown, as current knowledge of hereditary and acquired risk factors do not fully explain the highest risk of VTE in Black groups. In-depth studies across diverse ethnic populations are needed to unravel the whole genetics of VTE, which will help developing individual risk prediction models and strategies to minimise VTE in all populations.

Dysfunction of protein C anticoagulant system, main genetic risk factor for venous thromboembolism in northeast Asians

Venous thromboembolism (VTE) is a life threatening medical disorder worldwide. A great deal of evidence suggests that prevalence of VTE varies significantly among ethnic populations, with consistently lower incidence found in Asians. While the distribution of genetic risk factors may vary among races, genetic risk factors can play a major role among individuals with different genetic backgrounds. Two clinically evaluated low-frequency genetic mutations that predispose to VTE--the factor V Leiden mutation and prothrombin G20210A mutation--are found predominantly in Caucasians, and virtually never in Asians. The findings of a recent genetic study of VTE in northeast Asians, which greatly advanced our knowledge in this area, indicate that the most frequent genetic risk factors for VTE in northeast Asians can be attributed to a dysfunction of the protein C anticoagulant system. Several low-frequency genetic mutations, PROS1 p.Lys196Glu in Japanese and PROC p.Arg189Trp and p.Lys193del in Chinese, are significantly associated with increased risk for VTE, with odds ratio more than 2 through the reduced protein C anticoagulant activity. Construction of a multifactorial model based on the genetic risk factors in the protein C anticoagulant system could facilitate genetic counseling for VTE risk in these populations. The influence of prevalent genetic mutations on the risk of VTE should be further investigated in Asian countries.

Prognostic role of D-dimer in patients with lung cancer: a meta-analysis

D-dimer detection in patients suffering from a variety of different types of cancer has become a hot point as an emerging and promising biomarker. In this study, therefore, we evaluated the prognostic role of D-dimer in lung cancer. Initial literature was identified using the PubMed, EMBASE, and CNKI. The primary data was hazard ratio (HR) with 95% confidence interval (CI) of survival outcomes in candidate articles, including overall survival (OS) and disease-free survival (DFS). Finally, 11 eligible studies were included in this meta-analysis, which were published between 1996 and 2013. The estimated pooled HR and 95% CI for OS of all studies was 2.06 (95% CI 1.64-2.58, p < 0.00001) and the HR and 95% CI for DFS in one study was 3.38 (95% CI 1.17-9.75, p = 0.002). The HRs and 95% CIs for OS in Asian and non-Asian patients were 2.48 (95% CI 1.60-3.84, p < 0.0001) and 1.89 (95% CI 1.44-2.47, p < 0.00001), respectively. When we further analyzed the data by various detecting methods, the pooled HR and 95% CI for OS were 3.22 (95% CI 1.99-5.21, p < 0.00001) for ELISA, 1.52 (95% CI 1.25-1.86, p < 0.0001) for Latex assay, and 1.79 (95% CI 1.19-2.69, p = 0.005) for immunoturbidimetry assay. We also did subgroup analysis according to the ratio of histological type and clinical stage. All the above analysis had positive results. This meta-analysis showed that D-dimer had a fine predictive role in lung cancer patients, especially in Asian group. Also, it demonstrated that D-dimer had a stronger predictive value by using the method ELISA.

Hereditary thrombophilia in Korean patients with idiopathic pulmonary embolism

PURPOSE

Hereditary thrombophilia (HT) is a major risk factor for idiopathic pulmonary embolism (iPE) and shows different prevalence among ethnic groups. The prevalence and clinical characteristics of HT in Korean patients with iPE were investigated.

MATERIALS AND METHODS

Patients with PE on computed tomography (CT) scan were recruited, and those with malignancy were excluded. Patients were divided into iPE and provoked PE (pPE) groups. The presence of HT in the iPE group was assessed by DNA sequencing of the corresponding gene in patients who had low levels of natural anticoagulants. The clinical characteristics of iPE with HT (iPE/HT+) were compared with those of iPE without HT (iPE/HT-) and pPE.

RESULTS

Out of 161 patients, 84 patients had iPE and 77 patients had pPE. Among 54 patients in the iPE group whose coagulation profiles were tested, 28 patients were diagnosed with HT (51.9%; 28/54). Compared with the iPE/HT- and pPE groups, the iPE/HT+ group showed the highest proportion of male patients (71.4%; p<0.001); the youngest mean age (44±14 years; p<0.001); and the highest frequencies for history of venous thromboembolism (64.3%; p<0.001), concurrent deep vein thrombosis (75.0%; p=0.021), and adverse clinical outcomes (42.9%, p<0.001). Protein C deficiency was the most common HT. On molecular genetic tests, causative mutation was identified in 13 patients.

CONCLUSION

In this study of Korean patients, about half of the patients with iPE had HT. Patients with iPE and HT were mostly young males with deep venous thrombosis (DVT), previous venous thromboembolism (VTE), and frequent adverse clinical outcomes. Therefore, Korean patients with iPE should be tested for HT.

Protein C, protein S and von Willebrand factor levels correlate with bleeding symptoms: a population-based study

Although natural anticoagulant deficiencies are the established causes of thrombosis, their roles in bleeding are not fully studied. The objective is to correlate haemostatic factors with haemorrhagic symptoms quantified by a standardized questionnaire. Adult subjects were recruited from Bangkok and nearby provinces as part of routine health surveys/checkups. The validated MCMDM-1VWD form was used to assess their bleeding symptoms. At the same time, von Willebrand factor (VWF) activity, free protein S levels and protein C activity were measured. There were 5196 individuals. The mean age was 44.3 years (range 15-99) and 41% were male subjects. The mean bleeding score was -0.28 and 95% of subjects had scores between -2 and +2. The scores were lower in female subjects than in male subjects (-0.35 vs. -0.16, P < 0.001). Bleeding scores correlated negatively with age, VWF and protein C activities (Spearman's ρ-0.258, -0.091 and -0.098, respectively, all P < 0.001), but did not significantly correlate with protein S levels. Using multivariate analysis, female gender, VWF below 100 IU dL(-1), protein C below 100 IU dL(-1) and protein S over 150 IU dL(-1) significantly related to high (≥3) bleeding scores (adjusted odds ratio 1.95, 1.83, 1.56 and 2.84, P = 0.001, 0.001, 0.039 and 0.017, respectively). These findings may suggest interacting roles of VWF and natural anticoagulants in modifying bleeding symptoms.

Racial differences in venous thromboembolism

The incidence of venous thrombosis (VTE) varies by race, with African-Americans having over 5-fold greater incidence than Asian-ancestry populations, and an intermediate risk for European and Hispanic populations. Known racial differences in genetic polymorphisms associated with thrombosis do not account for this gradient of risk, nor do known racial variations in environmental risk factors. Data on the incidence of and risk factors for VTE outside of Europe and North America and in non-European ancestry populations are sparse. Common genetic polymorphisms in European-Ancestry populations, such as factor V Leiden and prothrombin G20210A, and environmental risk factors, such as obesity, may account for some of the increased risk in European populations, and high factor VIII, high von Willebrand factor and low protein C levels and increased prevalence of obesity may explain some of the increased risk in African-Americans. The low rates in Asian populations may be partially explained by low clinical suspicion in a perceived low-risk population and lack of access to healthcare in other populations. As risk factors for thrombosis, such as surgery and treatment for cancer, are applicable to more people, as obesity increases in prevalence in the developing world, and as surveillance systems for VTE improve, VTE may increase in previously low-risk populations. While differences in VTE by race due to genetic predisposition will probably always be present, understanding the reasons for racial differences in VTE will help providers develop strategies to minimize VTE in all populations.

High incidence of hepatitis B infection-associated cirrhosis and hepatocellular carcinoma in the Southeast Asian patients with portal vein thrombosis

Background

Portal vein thrombosis (PVT) is a rare condition associated with serious morbidity and mortality. The objective of this study was to determine the frequency, clinical presentations, and risk factors of PVT from the set of data firstly collected among the Southeast Asian population.

Methods

A retrospective study was undertaken to identify patients diagnosed with thrombosis of the portal system and other abdominal veins. The hospital medical records were retrieved based on the selected ICD-10 codes. Clinical presentations were collected and risk factors determined.

Results

From 2000-2009, 467 hospital charts with designated ICD-10 codes of I81, I82.2, I82.3, I82.8, I82.9, or K55.0 were identified. PVT (I81) was the most common thrombosis (194 cases, 41.54%). The majority of PVT patients were males (65%), older than 40 years (75%), and presented with abdominal distension/ascites (69%), splenomegaly (54.6%), and abdominal pain (50.5%). Overall, the predominant risk factor was hepatocellular carcinoma (HCC) (52.5%), followed by liver cirrhosis without cancer (9.3%), abdominal infection/inflammation (9.3%), cholangiocarcinoma (8.2%), and abdominal intervention (7.7%). In young patients, abdominal interventions including umbilical catheterization (23.1%) and hepatectomy (7.7%) were the most frequent risks whereas in older cases, primary hepatobiliary cancer and cirrhosis (78%) were the major risks. Liver metastases from other organs were infrequently found. Chronic hepatitis B virus (HBV) infection was the main etiology associated with cirrhosis/HCC leading to PVT in this cohort. A third of the older PVT patients (age >40) had HBV and very few carried hepatitis C virus (HCV) whereas none of the young PVT patients (age <20) had HBV or HCV. A variety of abdominal infections/inflammations were also found including liver abscess, splenic abscess, cholangitis, cholecystitis, pancreatitis, omphalitis, and abdominal tuberculosis. Single cases of systemic lymphangiomatosis and Klippel-Trénaunay vascular malformation syndrome were also identified. Other thrombophilic conditions such as myeloproliferative neoplasms, paroxysmal nocturnal hemoglobinuria, protein S deficiency, and anti-phospholipid syndrome were rarely encountered.

Conclusion

HBV is the major risk of PVT in the Southeast Asian population. Several risk factors identified in this population have rarely been described and some are remarkably different from those reported in the West. Host and environmental factors may play a causal role in the initiation and development of PVT in various ethnicities and geographic locations.

Low vegetable intake is strongly associated with venous thromboembolism in Thai population

Recent studies have demonstrated a much higher incidence of venous thromboembolism (VTE) among Asian patients compared with previous studies. This study aims to determine dietary and behavioral factors that may have contributed to this increase. A case-control study was conducted. Cases were objectively confirmed VTE between 2006 and 2009 at King Chulalongkorn Memorial Hospital. Patients with underlying cancer, antiphospholipid syndrome and arterial thrombosis were excluded. Controls were age and sex-matched healthy volunteers. Food consumption was assessed using a food frequency questionnaire modified from the Thailand National Health Examination Survey III previously validated in the Thai population. There were 97 cases and 195 controls. The mean age was 54.6 years and 70% were women. VTE patients consumed significantly less vegetable, fish and spicy food compared with normal individuals with an odds ratio (OR) for venous thrombosis of 3.74 [95% confidence interval (CI) 2.24-6.26, P < 0.001], 2.05 (95% CI 1.24-3.41, P = 0.005) and 2.30 (95% CI 1.29-4.11, P = 0.01), respectively. Additionally, thrombosis was associated with overweight (OR 2.1, 95% CI 1.21-3.62, P = 0.002), obesity (OR 3.1, 95% CI 1.46-6.74, P = 0.001) and estrogen uses (OR 3.7, 95% CI 1.05-13.2, P = 0.02), but not with smoking or lack of exercise. A multivariate analysis showed that low vegetable consumption (OR 3.74, 95% CI 1.85-7.55, P < 0.001), female hormones (OR 5.80, 95% CI 1.51-22.22, P = 0.011) and body mass index (BMI, P = 0.048) were independently associated with VTE. Low vegetable intake, hormonal use and high BMI are the risk factors for noncancer-related VTE in Thai population.

The effects of transdermal contraception on lipid profiles, carbohydrate metabolism and coagulogram in Thai women

OBJECTIVE

To evaluate the effects of the contraceptive patch on lipid profiles, carbohydrate metabolism and coagulogram in Thai women.

METHODS

Fifty healthy Thai women were assigned to use contraceptive patches. Blood chemistries test including liver function test, lipid profiles and coagulogram were evaluated at baseline, cycles 3 and 6.

RESULTS

Total cholesterol, triglyceride and HDL were significantly increased, whereas LDL was slightly decreased. The ratio of total cholesterol/HDL and LDL/HDL significantly decreased when applying the patch. After discontinued use of contraceptive patch, the women whose blood tests present hypercholesterol during patch use showed a continuous decrease in blood results of total cholesterol level over 3 months. Moreover, mean fasting glucose, SGOT, SGPT and alkaline phosphate were decreased. No woman suffering from VTE in this study.

CONCLUSIONS

The use of contraceptive patch does not exert a negative effect on carbohydrate metabolism, lipid profile, liver function test and blood coagulogram. However, further studies are required to elucidate the effect of the contraceptive on the patch user in long term.