High prevalence of antithrombin III, protein C and protein S deficiency, but no factor V Leiden mutation in venous thrombophilic Chinese patients in Taiwan

Validation for the function of protein C in mouse models

Objectives

Protein C (PC) is an anticoagulant that is encoded by the PROC gene. Validation for the function of PC was carried out in mouse models.

Methods

In this study, autosomal recessive PC deficiency (PCD) was selected as the target, and the specific mutation site was chromosome 2 2q13-q14, PROC c.1198G>A (p.Gly400Ser) which targets G399S (GGT to AGC) in mouse models. To investigate the role of hereditary PC in mice models, we used CRISPR/Cas9 gene editing technology to create a mouse model with a genetic PCD mutation.

Results

The two F0 generation positive mice produced using the CRISPR/Cas9 gene editing technique were chimeras, and the mice in F1 and F2 generations were heterozygous. There was no phenotype of spontaneous bleeding or thrombosis in the heterozygous mice, but some of them were blind. Blood routine results showed no significant difference between the heterozygous mice and wild-type mice (P > 0.05). Prothrombin time (PT), activated partial thromboplastin time (APTT), and thrombin time (TT) were prolonged in the heterozygous mice, while the level of fibrinogen content (FIB) decreased, suggesting secondary consumptive coagulation disease. The protein C activity of heterozygous mice was significantly lower than that of wild-type mice (P < 0.001), but there was no significant difference in protein C antigen levels (P > 0.05). H&E staining showed steatosis and hydrodegeneration in the liver of heterozygous mice. Necrosis and exfoliated epithelial cells could be observed in renal tubule lumen, forming cell or granular tubules. Hemosiderin deposition was found in the spleen along with splenic hemorrhage. Immunohistochemistry demonstrated significant fibrin deposition in the liver, spleen, and kidney of heterozygous mice.

Conclusion

In this study, heterozygotes of the mouse model with a PC mutation were obtained. The function of PC was then validated in a mouse model through genotype, phenotype, and PC function analysis.

The effects of dienogest and combined oral contraceptives on protein S-specific activity in endometriosis patients

OBJECTIVE

One serious side effect of combined oral contraceptives (COCs) is venous thromboembolism. Reduced activity in activated protein C-related coagulation pathways is attributable to low protein S activity in one-third of Japanese patients with deep vein thrombosis. Herer, we quantified the behavior of protein S-specific activity in response to dienogest (DNG) and COCs using the protein S-specific activity assay system to explore its potential utility as a thrombosis marker.

STUDY DESIGN

This was a prospective cohort study. Female patients aged 20 - 49 years who were starting drug treatment for endometriosis using DNG or COCs were enrolled. Blood samples were taken before treatment and at the first, third, and sixth months of treatment. To analyze the primary endpoints, changes in total protein S antigen levels, total protein S activity, and protein S-specific activity from baseline to each time point were estimated using a linear mixed-effects model. All statistical analyses were performed in the SAS software version 9.4 (SAS Institute, Cary, NC). A two-sided P < 0.05 was considered statistically significant.

RESULTS

64 patients took DNG and 34 patients took COCs. Protein S-specific activity did not change significantly from baseline in the six months after treatment started in either group. In the DNG group, total protein S activity and total protein S antigen levels increased slightly from baseline levels after the treatment. The means for total protein S activity and total protein S antigen levels in the COC group remained within reference limits, but they both decreased markedly in the first month and stayed low. Protein S-specific activity in four women remaind below the reference limit throughout the whole study period, suggesting they may have potential protein S deficiencies.

CONCLUSION

The effects of DNG on protein S were negligible, though both total protein S activity and antigen levels decreased soon after COC treatment began and remained low. As there was no VTE event during the study, further studies with larger numbers of patients will be needed to confirm that protein S-specific activity can be a surrogate maker of VTE risk.

Deep vein thrombosis after open hepatectomy or other major upper abdominal surgery in Taiwan: A prospective and cross-sectional study relevant to the issue of pharmacological thromboprophylaxis

BACKGROUD/PURPOSE

Venous thromboembolism, including deep vein thrombosis (DVT) and pulmonary embolism (PE), is an important complication in patients who underwent open hepatic surgery as well as other major upper abdominal surgery. This study aims to investigate the occurrence of postoperative DVT without pharmacological thromboprophylaxis in such cohorts in Taiwan.

METHODS

This is a prospective, cross-sectional cohort study conducted from March 2010 to December 2011. Patients who underwent major upper abdominal surgery, including open hepatectomy, were enrolled. Color duplex compression ultrasonography (CUS) was used to detect DVT. Symptomatic PE was excluded if there were no suggestive respiratory symptoms or sudden death. Relevant clinicopathological and surgical information of each patient was collected and analyzed.

RESULTS

195 patients (118 male and 77 female) were enrolled, with a median age of 63.6 years. The majority (169/195, 88.7%) were treated for active malignancy. Totally 147 patients received open hepatectomy. Only one asymptomatic and distal postoperative DVT event was identified by CUS, which occurred on a 73-year-old female patient who received a left lateral segmental hepatectomy for removing the advanced hepatocellular carcinoma (pathologic stage, T3aN0M0). No cases of symptomatic PE or sudden death were observed. No correlation between DVT and precipitating factor was demonstrated in our cohort.

CONCLUSION

Without pharmacological thromboprophylaxis, a low rate of postoperative DVT among patients undergoing open hepatectomy (0.7%, 1/147) or major upper abdominal surgery (0.5%, 1/195) in Taiwan was reported. A distinctively regional role of pharmacological thromboprophylaxis for hepatic surgery was also suggested by our data.

Hereditary protein C deficiency with portal vein thrombosis in a Chinese male: A case report

Hereditary protein C deficiency (PCD) is caused by mutation in the PC gene (PROC). The homozygous mutation form of PCD is rare. Furthermore, in Asia, cases of noncirrhotic patients with portal vein thrombosis (PVT) secondary to PCD have been rarely reported. The present study reported the case of a patient with PVT due to hereditary PCD. Of note, the mutation of PROCc.152G>A was observed in the patient of the present study. According to the current literature, there has been no previous report regarding the mutation of this gene in China. The patient suffered abdominal pain for 20 days, which was accompanied by vomiting for 2 days. Multiple ulcers and diverticula in the sigmoid colon, as well as erosive small ulcers throughout the colon, were discovered during a colonoscopy. Abdominal angiography indicated thrombosis of the portal vein and its branches. Furthermore, laboratory parameters indicated a hypercoagulable state with normal PC antigen values but decreased PC activity. The discovery of blood coagulation-related genes suggested that homozygous mutation in PC resulted in an amino acid missense mutation. Anticoagulants were prescribed after a diagnosis of type II hereditary PCD with PVT was made. After 15 days, the blood coagulation function of the patient was restored to normal and the symptoms were substantially alleviated. Hence, the present study expanded the mutation spectrum of PROC in China and reaffirmed the value of anticoagulant therapy in PCD.

Deep vein thrombosis after major orthopedic surgery in Taiwan: A prospective cross-sectional study and literature review

BACKGROUND/PURPOSE

Postoperative venous thromboembolism is an important complication in Taiwan. We prospectively investigated the occurrence of deep vein thrombosis (DVT) after major orthopedic surgery without pharmacologic thromboprophylaxis in a cohort of 120 patients (46 males, 74 females, median age 71 years) at our institute.

METHODS

Color duplex compression ultrasonography (CUS) was used to detect DVT before and after the operation, while contrast venography was performed postoperatively for comparison and validation.

RESULTS

Total knee arthroplasty (TKA, 57 cases) and total hip arthroplasty (23 cases) were the most commonly performed operations. The rate of postoperative DVT was 7.5% (9/120), including five with proximal DVT and four with distal DVT. All were detected in the limbs on the operated side. Four of them were symptomatic DVT cases. Venography was performed in 19 patients and confirmed most findings of CUS, indicating the effectiveness of CUS for detecting DVT. The type of surgery (TKA) was significantly correlated with postoperative DVT. No clinically symptomatic pulmonary embolism or sudden death events were noted.

CONCLUSION

Nine out of 120 (7.5%) orthopedic patients without pharmacologic thromboprophylaxis developed postoperative sonographic DVT in our study. The DVT rate is consistent with other reports from various Asian countries and evidence from meta-analyses.

Clinical and genetic features of Chinese pediatric patients with severe congenital protein C deficiency who first presented with purpura fulminans: A case series study and literature review

INTRODUCTION

Purpura fulminans (PF) is a hematological emergency that can be caused by severe congenital protein C (PC) deficiency. It has been rarely reported in the Chinese population. We aimed to characterize the clinical and genetic features of Chinese pediatric patients with severe congenital PC deficiency who first presented with PF.

MATERIALS AND METHODS

Twelve pediatric patients were diagnosed with severe congenital PC deficiency with PF, which was diagnosed based on our hospital records and previous reports from 1988 to July 2021 in China. We evaluated the clinical and genetic features of these patients.

RESULTS

Nine patients (9/12, 75%) had onsets that were observed within the first 48 h after birth. Six patients had a family history of thromboembolism. There was no consanguinity. Other symptoms were intracranial thrombosis or hemorrhage (4, 33.3%), ocular lesions (2, 16.7%), gastrointestinal hemorrhage (2, 16.7%) and kidney infarction before birth (1, 8.3%). All but one of the patients (one case not detected) had a plasma PC activity of <10%. The genetic study indicated that in the eight patients with inherited PC deficiency, two were homozygous, five were compound heterozygous and one was heterozygous for PC deficiency.

CONCLUSION

This is the first and largest case series of Chinese pediatric patients with severe congenital PC deficiency who first presented with PF. It has been shown that treatment with both fresh frozen plasma and anticoagulants is recommended when PC concentrate is not easily available, especially in developing countries.

Association between congenital thrombophilia and outcomes in pulmonary embolism patients

The prevalence and distribution of congenital thrombophilia is still unclear in patients with pulmonary embolism (PE). We aimed to determine the prevalence and clinical characteristics of congenital thrombophilia in PE patients and their subsequent outcomes. A prospective observational study was conducted from May 2013 to June 2018. A total of 436 consecutive patients with PE were enrolled. All patients were tested for protein C, protein S, antithrombin III (ATIII), factor V Leiden, and prothrombin G20210A mutations. The median follow-up duration was ∼800 days (range, 11-1872 days). Congenital thrombophilia was diagnosed in 31 of 436 (7.1%) patients; 12 patients had protein C deficiency (2.8%), 13 had protein S deficiency (3.0%), 5 had ATIII deficiency (1.1%), and 1 had (0.2%) factor V Leiden. Age ≤50 years at the first episode (odds ratio [OR], 5.43; 95% confidence interval [CI], 2.35-13.52; P < .001) and male sex (OR, 2.67; 95% CI, 1.15-6.78; P = .03) were 2 independent predictors of congenital thrombophilia in PE patients. There was no statistically significant difference in the prevalence of congenital thrombophilia between PE patients with and without risk factors (P = .58). We also found no significant difference in the risk of having a composite outcome of death or recurrent venous thromboembolism between patients with and without congenital thrombophilia (hazard ratio, 0.18; 95% CI, 0.02-5.69; P = .08). These results suggest that age and male sex are independently associated with the occurrence of congenital thrombophilia in PE patients but that congenital thrombophilia is not associated with the risk of recurrence or death with anticoagulation therapy.

Pathogenic variants of PROC gene caused type II activity deficiency in a Chinese family: A case report

RATIONALE

Hereditary Protein C (PC) deficiency is a rare genetic disorder caused by PROC gene mutation. In this article, we report a case of PC deficiency in a Chinese family due to a novel PROC gene mutation.

STUDY SUBJECT

The proband presented with recurrent cerebral infarction over the course of the previous 3 years. He was admitted to the hospital due to signs of mental retardation.

DIAGNOSES

Physical examination, laboratory tests, and magnetic resonance imaging demonstrated that the proband had a manifestation of PC deficiency that included acute cerebral infarction. DNA sequencing analysis revealed a missense variant, c.1015G > A (p.V339 M from valine to methionine) in exon 9 of the PROC gene. In addition, Sanger sequencing confirmed that the proband's son was heterozygous for the same variant. Therefore, the PROC gene mutation was transmitted in an autosomal dominant inheritance manner.

INTERVENTIONS

The patient was treated with a daily dosage of Warfarin (3.5 mg) and was scheduled to undergo regular blood coagulation tests.

OUTCOMES

At the 3-month follow-up appointment, the patient showed improvements in his overall health condition.

LESSONS

We identified a novel missense mutation in the PROC gene in a Chinese family which caused a decrease in the PC antigen level and recurrent cerebral infarction.

Recurrent PROC and novel PROS1 mutations in Vietnamese patients diagnosed with idiopathic deep venous thrombosis

INTRODUCTION

Genetic mutations of PROC and PROS1 are well-known risk factors for deep venous thrombosis (DVT) in the Asian population. However, the genetic profile of Vietnamese patients with DVT remains elusive. This study aimed to investigate the spectrum of genetic mutations of these two genes in Vietnamese patients diagnosed with idiopathic DVT.

MATERIALS AND METHODS

A total of 50 Vietnamese patients diagnosed with idiopathic DVT were recruited in this study. The entire coding regions of the protein C and protein S genes were amplified and directly sequenced to determine genetic alterations.

RESULTS

Four and six genetic mutations were detected in protein C and protein S genes, respectively, in 24 Vietnamese DVT patients. PROC c.565C > T (p.R189W) was the most common mutation found in 13 out of 50 patients, while the mutations of PROS1 comprised three missense and three nonsense variants which diffuse along the gene.

CONCLUSIONS

This study shows that mutations of protein C and protein S genes are prevalent in Vietnamese patients diagnosed with idiopathic DVT, and PROC c.565C > T (p.R189W) was the most common genetic alteration.

INHERITED PROTEIN C AND PROTEIN S DEFICIENCY IN RENAL TRANSPLANT CANDIDATES OF SINDH PROVINCE, PAKISTAN

Background: Thrombophilia is a common risk factor for venous thromboembolism. The objective of this study was to determine prevalence of inherited protein C and protein S deficiency in renal transplant candidates of Sindh Province, Pakistan. Material & Methods: This cross-sectional study was conducted in Department of Pathology, Sindh Institute of Urology and Transplantation, Karachi, Pakistan from 16-10-2010 to 15-4-2011. 300 renal transplant candidates were selected. Candidates with acquired thrombotic disorders, women taking oral contraceptives and patients taking anti-coagulants during previous one week were excluded. Venous blood samples were collected before starting dialysis procedure or at least two days after last dialysis session. Platelet-poor plasma (PPP) was parted using plastic pipettes and protein C and protein S were processed on coagulation analyzer. Sex, age groups (<40 and ≥ 40years), presence of protein C deficiency and presence of protein S deficiency were nominal variables and analyzed by count and percentage along with population parameters. Results: 300 renal transplant candidates included 199 (66.33%) men and 101 (33.67%) women and 238 (79.33%) in age group <40 years and 62 (20.67%) cases in age group ≥40 years. Prevalence of protein C deficiency was 6.66% (20/300) and of protein S deficiency was 4% (12/300). Prevalence of PC deficiency was higher in men 5.33% than women 1.33%. Also prevalence of PS deficiency was higher in men 3.0% than women 1.0%. Prevalence of PC deficiency was higher in age group <40 years 5.67% than ≥40 years 1.0%. Also prevalence of PS deficiency was higher in age group <40 years 3.33% than ≥40 years 0.66%. Conclusion: More prolonged and follow-up studies are needed to define the true significance of deficiency of protein C and S (coagulation inhibitors) in post-transplant settings.

Stroke during pregnancy and puerperium among Japanese women: a single-center registry

BACKGROUND

Stroke is one of the major causes of maternal death. This study aimed to analyze the maternal and fetal outcomes of stroke occurred during pregnancy and puerperium.

METHODS

We conducted a retrospective analysis of patients admitted to our perinatology center between 1982 and 2012 with a diagnosis of acute cerebral stroke during pregnancy or within 6 weeks postpartum.

RESULTS

Thirty-four patients were registered and all the patients had never been diagnosed as stroke nor detected cerebrovascular abnormalities before the current pregnancies. They were divided into 8 ischemic strokes (ISs) and 26 intracranial hemorrhage group. In the hemorrhage group, there was a spontaneous abortion and two patients chose artificial abortions to avoid rehemorrhage, and there were another three intrauterine fetal deaths (IUFDs) in the acute stage of maternal stroke. More patients in hemorrhage group delivered in preterm than in IS group for the treatment of stroke, 10/23 (43%) versus 0/8 (0%), p < .05. More patients in hemorrhage group had low Glasgow Coma Scale (GCS) (3-8) than in IS group at the onset of the stroke, 12/26 (46%) versus 0/8 (0%), p < .05. There were three maternal deaths and 6/23 (26%) were neurologically dependent in hemorrhage group in the chronic stage, whereas 87% were independent in IS group, p < .05.

CONCLUSIONS

Hemorrhagic stroke was more common etiology of stroke related to pregnancy than IS in this study. Intensive and multidisciplinary care was needed especially in hemorrhagic stroke related to pregnancy as in the hemorrhagic stroke the fetal survival rate was lower, and maternal conscious levels at the onset of the stroke and neurological outcomes in the chronic stage were worse than IS.

Genotypic and phenotypic character of Chinese neonates with congenital protein C deficiency: a case report and literature review

Background

Our objective was to study the phenotype of and molecular genetic mechanisms underlying congenital protein C (PC) deficiency in Chinese neonates. We report the case of a neonate who presented 4 h after birth with purpura fulminans of the skin and thrombosis in the kidney. We also carried out a through literature review to study the genotype and phenotype, relevance, diagnosis, management, and prognosis of neonates with congenital PC deficiency in China.

Case presentation and literature review

Following a septic work-up and check of PC and protein S (PS) levels that showed PC deficiency, we investigated the patient’s and her parents’ genotypes. Our patient was found to have a plasma PC level of 0.8%. Molecular testing revealed a compound heterozygous mutation of the PROC gene: From the father, a c._262 G > T p. ASP88Tyr mutation in exon 4; from the mother, a C. 400 + 5G mutation in intron 5 that had been previously reported as likely pathogenic. Both parents were found to have heterozygous mutations for PC deficiency. In China, 5 other cases of congenital PC deficiency in the neonatal period were reported in the literature. In those cases, purpura fulminans and thrombosis were the main symptoms, and homozygous or compound heterozygous mutations of the PROC gene were identified.

Conclusion

Congenital PC deficiency should be ruled out for neonates presenting with purpura fulminans and thrombosis.

Analysis of PROC and PROS1 single nucleotide polymorphisms in a thrombophilia family

OBJECTIVE

The aim of this study was to assess the association of single nucleotide polymorphisms (SNPs) in protein C (PROC) and protein S (PROS1) genes with deep venous thrombosis (DVT) in a thrombophilia family.

METHODS

DNA were extracted from blood of participants. Five PROC SNPs and 11 PROS1 SNPs were selected from the Hapmap and 1000 Genomes databases. The minor allele frequencies (MAFs) of SNPs in the thrombophilia family (Group I) and healthy controls (Group II) were detected. SNPs were analysed by Chi-square, logistic regression and linkage disequilibrium patterns.

RESULTS

MAFs for all 16 SNPs were greater than 0.05. Chi-square analysis showed significant differences between Group I and Group II in the frequency of mutant alleles of rs1799808, rs5936, rs6123, rs12634349, rs6441600 and rs13062355 SNPs (P < .05). Logistic regression analysis found that mutant alleles of rs1799808, rs6441600 and rs13062355 SNPs may contribute to DVT in this family (OR > 1, L95 > 1). Linkage disequilibrium was found among 15 of the PROC and PROS SNPs.

CONCLUSIONS

Single nucleotide polymorphisms (SNPs) of PROC and PROS1 may be closely associated with DVT in this thrombophilia family. Mutant alleles of rs1799808, rs6441600 and rs13062355 SNPs may contribute to DVT, whereas mutant alleles of rs1799810, rs6123 and rs12634349 may protect individuals from DVT. With the exception of rs9681204, there was linkage disequilibrium between PROC and PROS1 SNPs. We found that 12 haplotypes were in linkage disequilibrium, but linkage disequilibrium was strong in only eight of these (frequency >5%).

Thrombophilia Associated with Early Post-angioplasty Thrombosis of Dialysis Vascular Access

AIM

Percutaneous transluminal angioplasty (PTA) is widely used as the primary treatment for dialysis vascular access dysfunction. Nonetheless, many patients develop early occlusion after angioplasty. Thus, we investigated the role of thrombophilia in access occlusion within 30 days of angioplasty.

MATERIALS AND METHODS

This case-control study included patients who underwent PTA for dialysis vascular access dysfunction. Patients who experienced occlusion within 30 days of angioplasty were included in the case group and those without occlusion for at least 30 days after angioplasty were included in the control group. All patients were tested for protein C, protein S, antithrombin III, lupus anticoagulant, and anticardiolipin antibodies.

RESULTS

From February to October 2015, 462 patients underwent PTA for dialysis vascular access dysfunction. Forty-one patients (8.9%) had early occlusion within 30 days of angioplasty. The case group had more graft accesses (73 vs. 31%, P < 0.001) and thrombotic occlusions (67 vs. 15%, P < 0.001). A higher incidence of protein C (10 vs. 2%), protein S (15 vs. 5%), and antithrombin III (10 vs. 2%) deficiency and elevated anticardiolipin antibody (22 vs. 10%) levels were observed in the case group. Overall, 26 patients (63%) in the case group had at least one thrombophilic factor, compared with 15 patients (37%) in the control group (unadjusted odds ratio [OR], 3.004; 95% confidence interval [CI], 1.223-7.380; P = 0.027). After adjustment for confounding factors, the association between thrombophilic factors and early occlusion remained (adjusted OR, 3.806; 95% CI, 1.018-14.220; P = 0.047).

CONCLUSION

Thrombophilia is associated with early occlusion after angioplasty for hemodialysis vascular access.

Analysis of preventability of hypertensive disorder in pregnancy-related maternal death using the nationwide registration system of maternal deaths in Japan

Objective: Hypertensive disorder of pregnancy (HDP) is a major cause of maternal death. The goal of this study was to investigate factors associated with maternal death due to HDP. Study design: HDP-related maternal deaths in Japan reported to the Committee of the Ministry of Health, Labor and Welfare from 2010 to 2015 were examined. Results: Out of 47 cases of HDP, 30 were identified as the major cause of maternal death. The median maternal age was 34 years (range 24-45) and the mortality in women aged ≥40 years was seven times higher that than in women aged <34 years. The etiologies were intracerebral hemorrhage (n = 22), subarachnoid hemorrhage (n = 3), subcapsular hematoma of the liver (n = 2), peripartum cardiomyopathy (n = 2), and eclampsia (n = 1), and 19 cases were deemed preventable. The most frequent antepartum problems were delays in hospitalization, maternal transfer, and termination of pregnancy. In four cases, diagnosis of HELLP syndrome was too late because laboratory data were not checked, despite the patient reporting epigastric pain or showing elevation of blood pressure (BP). Treatment for lowering of BP was improper in 2/3 intrapartum cases, even though BP was elevated during pregnancy (144 versus 188 mmHg, p < .001). There was inadequate lowering of BP and lack of use of magnesium sulfate in 7/11 postpartum cases (64%), despite aspartate aminotransferase (AST) (p < .005), alanine aminotransferase (ALT) (p < .01), lactate dehydrogenase (LDH) (p < .005), and platelet count (PLT) (p < .01) all significantly worsening after delivery. Conclusion: HDP accounts for 11% of maternal deaths in Japan. Mothers aged ≥40 years are most at risk for HDP-related maternal death. Major concerns for preventabilities were late hospitalization, maternal transportation, and termination of pregnancy for term or near-term HDP. Regular vital checks and prompt lowering of BP were lacked during labor in most cases. HELLP syndrome should be managed at a general hospital with sufficient medical resources.

Successful medical management of acute mesenteric ischemia due to superior mesenteric and portal vein thrombosis in a 27-year-old man with protein S deficiency: a case report

Background

Acute mesenteric ischemia poses a diagnostic challenge due to nonspecific clinical clues and lack of awareness owing to its rarity. Ischemia due to mesenteric venous thrombosis has a good prognosis compared to arterial cause and can be managed conservatively with early diagnosis. The portomesenteric venous system is an unusual site of thrombosis in patients with protein S deficiency, and its thrombosis is an uncommon cause of acute mesenteric ischemia.

Case presentation

We present a case of a 27-year-old Mongolian man who presented with acute abdominal pain increasing in severity, and refractory to repeated attempts at treatment with a misdiagnosis of acute peptic ulcer disease. Contrast-enhanced computed tomography of his abdomen detected complete occlusion of the superior mesenteric vein, an extension of acute thrombus into the portal vein, and ischemic mid-jejunal loops. Early diagnosis and immediate anticoagulation with continuous intravenous infusion of unfractionated heparin prevented subsequent consequences. On further workup, our patient was diagnosed with isolated protein S deficiency. We started lifelong thromboprophylaxis with warfarin to prevent recurrence and our patient was asymptomatic on the latest follow-up 5 months after discharge.

Conclusion

Despite accurate detection of acute mesenteric ischemia by contrast-enhanced computed tomography, high index of suspicion is indispensable for its early diagnosis. Early diagnosis and immediate anticoagulation will prevent subsequent complications and need for surgical intervention. Young patients without known risk factors presenting with venous thrombosis in atypical sites should be investigated for prothrombotic diseases.

Edoxaban improves acute venous thromboembolism while preserving protein C and protein S levels

BACKGROUND

It is well known that warfarin inhibits the synthesis of vitamin K-dependent anticoagulants, including thrombin, protein C and S, and factor Xa, leading, paradoxically, to an initial hypercoagulable state. Edoxaban, a direct inhibitor of activated factor X is widely used for the treatment of acute venous thromboembolism (VTE). However, the effect of edoxaban on circulating coagulation factors, in patients with acute VTE, remains unknown.

METHODS AND RESULTS

We enrolled 57 patients with acute VTE with/without pulmonary embolism treated with edoxaban (n=37) or warfarin (n=20) in a clinical setting. Before treatment and 2 weeks after treatment, we evaluated thrombotic burden using ultrasound or computed tomography angiography. We also evaluated thrombin generation, represented by prothrombin fragment F1+2; thrombus degradation, represented by D-dimer; and levels of anticoagulants, including protein C, protein S, and antithrombin III. Both edoxaban and warfarin treatment improved thrombotic burden and decreased prothrombin fragment F1+2, and D-dimer. Edoxaban treatment preserved protein C and protein S levels. In contrast, warfarin decreased protein C and protein S levels. Neither treatment affected antithrombin III.

CONCLUSIONS

Edoxaban improves VTE while preserving protein C and protein S levels, thereby indicating that edoxaban improves thrombotic burden while maintaining levels of anticoagulants.

The prevalence and clinical manifestation of hereditary thrombophilia in Korean patients with unprovoked venous thromboembolisms

Background

Hereditary thrombophilia (HT) is a genetic predisposition to thrombosis. Asian mutation spectrum of HT is different from Western ones. We investigated the incidence and clinical characteristics of HT in Korean patients with unprovoked venous thromboembolism (VTE).

Methods

Among 369 consecutive patients with thromboembolic event who underwent thrombophilia tests, we enrolled 222 patients diagnosed with unprovoked VTE. The presence of HT was confirmed by DNA sequencing of the genes that cause deficits in natural anticoagulants (NAs). Median follow-up duration was 40±38 months.

Results

Among the 222 patients with unprovoked VTE, 66 (29.7%) demonstrated decreased NA level, and 33 (14.9%) were finally confirmed to have HT in a genetic molecular test. Antithrombin III deficiency (6.3%) was most frequently detected, followed by protein C deficiency (5.4%), protein S deficiency (1.8%), and dysplasminogenemia (1.4%). The HT group was significantly younger (37 [32–50] vs. 52 [43–65] years; P < 0.001) and had a higher proportion of male (69.7% vs. 47%; P = 0.013), more previous VTE events (57.6% vs. 31.7%; P = 0.004), and a greater family history of VTE (43.8% vs. 1.9%; P < 0.001) than the non-HT group. Age <45 years and a family history of VTE were independent predictors for unprovoked VTE with HT (odds ratio, 9.435 [2.45–36.35]; P = 0.001 and 92.667 [14.95–574.29]; P < 0.001).

Conclusions

About 15% of patients with unprovoked VTE had HT. A positive family history of VTE and age <45 years were independent predictors for unprovoked VTE caused by HT.

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.

Analysis of preventability of stroke-related maternal death from the nationwide registration system of maternal deaths in Japan

OBJECTIVE

The number of stroke-related maternal deaths is increasing in Japan. We investigated methods to reduce maternal death from stroke.

METHODS

We analyzed stroke-related maternal deaths in Japan reported to the Committee of the Ministry of Health, Labor, and Welfare from 2010 to 2014 inclusive.

RESULTS

A total of 35 cases were identified. The median maternal age was 35 years (range 22-45) and the incidence of stoke in women ≥40 was seven-fold higher than in <34. Etiologies were pregnancy induced hypertension in 16, subarachnoid hemorrhage in seven, cerebral infarction in three, arteriovenous malformation in two, Moyamoya disease in one, and origin unknown cerebral hemorrhage in six. These cases occurred in antepartum 43%, in postpartum 31%, and in intrapartum 26%. 23 cases were deemed non-preventable and 12 cases preventable. Possible preventable factors occurred antepartum in 23, postpartum in seven, and intrapartum in six. Preventable features included inadequate hypertension control (33%), presenting too late for termination of pregnancy (14%), delayed hospitalization (11%), and delayed maternal transfer (11%).

CONCLUSIONS

A total of 90% of strokes were hemorrhagic, and older mothers (≥ 40) were most at risk. Most possible preventable factors occurred antepartum, and improved control of hypertension and earlier termination would help to reduce maternal death from stroke.

Review article: the aetiology of primary Budd-Chiari syndrome - differences between the West and China

BACKGROUND

China may have the largest number of Budd-Chiari syndrome (BCS) cases in the world (at least 1914 original papers were published, and at least 20 191 BCS patients were reported). Considering the discrepancy in the clinical profiles and preferred treatment selection of primary BCS between the West and China, understanding its aetiology in these two different regions is very important.

AIM

To review the data from large cohort studies and meta-analyses to illustrate the epidemiology of risk factors for BCS in the West and China.

METHODS

Relevant papers were identified by major English- and Chinese-language databases, conference abstracts, and by manual search.

RESULTS

Risk factors reviewed include myeloproliferative neoplasms (MPNs) and their related gene mutations, anti-phospholipid syndrome, paroxysmal nocturnal haemoglobinuria (PNH), hyperhomocysteinaemia and 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T mutation, factor V Leiden (FVL) and prothrombin G20210A mutations, inherited anti-thrombin, protein C and protein S deficiencies, pregnancy and puerperium, poverty, and family history.

CONCLUSIONS

We examined the differences in the aetiological distribution of BCS between the West and China. Several recommendations should be considered in Chinese BCS patients: (i) screening for hyperhomocysteinaemia and MTHFR mutation should be regularly performed; (ii) screening for MPNs, PNH, and anti-phospholipid syndrome should be selectively performed; (iii) inherited anti-thrombin, protein C, and protein S deficiencies should be actively explored; (iv) screening for FVL and prothrombin G20210A mutations may be unnecessary; and (v) the clinical significance of pregnancy and puerperium, poverty with bacterial infections and unsanitary environments, and family history as possible risk factors should never be neglected.

Low-molecular-weight-heparin can benefit women with recurrent pregnancy loss and sole protein S deficiency: a historical control cohort study from Taiwan

BACKGROUND

Heritable thrombophilias are assumed important etiologies for recurrent pregnancy loss. Unlike in the Caucasian populations, protein S and protein C deficiencies, instead of Factor V Lieden and Prothrombin mutations, are relatively common in the Han Chinese population. In this study we aimed to investigate the therapeutic effect of low molecular weight heparin upon women with recurrent pregnancy loss and documented protein S deficiency.

METHODS

During 2011-2016, 68 women with recurrent pregnancy loss (RPL) and protein S deficiency (both the free antigen and function of protein S were reduced) were initially enrolled. All the women must have experienced at least three recurrent miscarriages. After excluding those carrying balanced translocation, medical condition such as diabetes mellitus, chronic hypertension, and autoimmune disorders (including systemic lupus erythematosus and anti-phospholipid syndrome), coexisting thrombophilias other than persistent protein S deficiency (including transient low protein S level, protein C deficiency, and antithrombin III), only 51 women with RPL and sole protein S deficiency were enrolled. Initially they were prescribed low dose Aspirin (ASA: 100 mg/day) and unfortunately there were still 39 women ended up again with early pregnancy loss (12 livebirths were achieved though). Low-molecular-weight-heparin (LMWH) was given for the 39 women in a dose of 1 mg/Kg every 12 h from the day when the next clinical pregnancy was confirmed to the timing at least 24 h before delivery. The perinatal outcomes were assessed.

RESULTS

Of 50 treatment subjects performed for the 39 women (i.e. 11 women enrolled twice for two pregnancies), 46 singletons and one twin achieved livebirths. The successful live-birth rate in the whole series was 94 % (47/50). Nineteen livebirths delivered vaginally whereas 28 delivered by cesarean section. The cesarean delivery rate is thus 59.57 %. Emergent deliveries occurred in 3 but no postpartum hemorrhage had been noted.

CONCLUSIONS

Our pilot study in Taiwan, an East Asian population, indicated anti-coagulation therapy is of benefit to women with recurrent pregnancy loss who had documented sole protein S deficiency.

TRIAL REGISTRATION

ISRCTN64574169. Retrospectively registered 29 Jun 2016.

Diagnosis and Treatment of Lower Extremity Deep Vein Thrombosis: Korean Practice Guidelines

Lower extremity deep vein thrombosis is a serious medical condition that can result in death or major disability due to pulmonary embolism or post-thrombotic syndrome. Appropriate diagnosis and treatment are required to improve symptoms and salvage the affected limb. Early thrombus clearance rapidly resolves symptoms related to venous obstruction, restores valve function and reduces the incidence of post-thrombotic syndrome. Recently, endovascular treatment has been established as a standard method for early thrombus removal. However, there are a variety of views regarding the indications and procedures among medical institutions and operators. Therefore, we intend to provide evidence-based guidelines for diagnosis and treatment of lower extremity deep vein thrombosis by multidisciplinary consensus. These guidelines are the result of a close collaboration between interventional radiologists and vascular surgeons. The goals of these guidelines are to improve treatment, to serve as a guide to the clinician, and consequently to contribute to public health care.

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.

Efficiency of Systematic Thrombophilia Screening in Idiopathic Venous Thrombosis: A Prospective Study in Internal Medicine

In case of unprovoked venous thromboembolism (VTE), the screening of thrombophilia is recommended whatever the age of the patient and the type of risk factors (RF). This prospective study was conducted in patients with unprovoked VTE to detect some predictive factors to have a higher risk of thrombophilia, focusing on age, history of venous thromboembolism, and the existence of a triggering event. From July 2000 to July 2002, in an Internal Medicine Department, unrelated patients with unprovoked VTE were included. Those unprovoked thromboembolic events were defined by the absence of association between permanent and transient RF. The primary outcome measure was the positivity of the thrombophilia screening for any type of abnormality detected (deficit of protein C, S, antithrombin, presence of a lupus anticoagulant, research of V and II mutations). Seventy-four patients were included. Eight died during the follow-up. A higher risk of thrombophilia was found in patients younger than 40 (p=0.03), or with a family but not personal history of VTE (p=0.01) or with transient RF (p=0.02). The most frequent abnormality of coagulation found in patients younger than 40 was the presence of a lupus anticoagulant. As a new strategy for the screening of thrombophilia, one could propose the following attitude: only patients with transient RF or family history of VTE could undergo a complete screening; for all the remaining patients who are younger than 40, a research of a lupus anticoagulant would be only performed. This strategy should now be balanced against the currently recommended systematic attitude in further studies.

Thrombophilia in Korean patients with arterial or venous thromboembolisms

Purpose

To determine the prevalence of thrombophilia in Korean patients with an arterial thromboembolism (ATE) or a venous thromboembolism (VTE), and to evaluate the characteristic of VTE in patients with thrombophilia.

Methods

Hospital records of 294 patients (228 with VTE, 66 with ATE) including two foreign ones (mean age, 51.4 years) who underwent thrombophilia testing between August 2006 and March 2015 were reviewed retrospectively. In general, such screening was performed according to the guidelines of the international consensus statement for VTE. Thrombophilia testing included evaluations of the factor V Leiden and prothrombin G20210A mutations, levels of proteins C and S and antithrombin, and antiphospholipid antibody syndrome (APLS).

Results

A factor V Leiden mutation was not found in the 292 Korean patients. A prothrombin G21210A mutation was investigated in 33 patients but none was found. Among 226 Korean patients with VTE, 130 demonstrated no thrombophilia and 55 patients did after exclusion of 41 patients without confirmatory test. The most common form was protein S deficiency (31 of 55, 56%) followed by protein C deficiency, antithrombin deficiency, and APLS. When comparing patients with a VTE or deep vein thrombosis (DVT) according to the presence of thrombophilia, thrombophilia was associated with younger age (P = 0.001 for VTE; P < 0.001 for DVT) and a family history (P < 0.001 for VTE and DVT).

Conclusion

We did not find any factor V Leiden mutation in Korean subjects at high risk for thrombophilia. Therefore, this testing is not warranted. Thrombophilia was associated with VTE in younger age and a family history.

Management of Venous Thromboembolisms: Part I. The Consensus for Deep Vein Thrombosis

Deep vein thrombosis (DVT) is a potentially catastrophic condition because thrombosis, left untreated, can result in detrimental pulmonary embolism. Yet in the absence of thrombosis, anticoagulation increases the risk of bleeding. In the existing literature, knowledge about the epidemiology of DVT is primarily based on investigations among Caucasian populations. There has been little information available about the epidemiology of DVT in Taiwan, and it is generally believed that DVT is less common in Asian patients than in Caucasian patients. However, DVT is a multifactorial disease that represents the interaction between genetic and environmental factors, and the majority of patients with incident DVT have either inherited thrombophilia or acquired risk factors. Furthermore, DVT is often overlooked. Although symptomatic DVT commonly presents with lower extremity pain, swelling and tenderness, diagnosing DVT is a clinical challenge for physicians. Such a diagnosis of DVT requires a timely systematic assessment, including the use of the Wells score and a D-dimer test to exclude low-risk patients, and imaging modalities to confirm DVT. Compression ultrasound with high sensitivity and specificity is the front-line imaging modality in the diagnostic process for patients with suspected DVT in addition to conventional invasive contrast venography. Most patients require anticoagulation therapy, which typically consists of parenteral heparin bridged to a vitamin K antagonist, with variable duration. The development of non-vitamin K oral anticoagulants has revolutionized the landscape of venous thromboembolism treatment, with 4 agents available,including rivaroxaban, dabigatran, apixaban, and edoxaban. Presently, all 4 drugs have finished their large phase III clinical trial programs and come to the clinical uses in North America and Europe. It is encouraging to note that the published data to date regarding Asian patients indicates that such new therapies are safe and efficacious. Ultimately, our efforts to improve outcomes in patients with DVT rely on the awareness in the scientific and medical community regarding the importance of DVT.

KEY WORDS

Combination therapy; Hypertension; α1-blocker.

Genetic association of PROC variants with pulmonary embolism in Northern Chinese Han population

To evaluate SNPs (single nucleotide polymorphism) in PROC (protein C gene) associated with pulmonary embolism (PE) susceptibility in North Chinese Han population. A case-control study design was used, and patients with PE and healthy participants were enrolled from the Emerging Department of the several hospitals in Weifang, Shandong, China. SNPs in PROC were genotyped using Mass ARRAY system. The allele frequency of rs199469469 was significantly different between PE patients and the control [OR (95 % CI) = 5.00 (1.66-15.12), P = 0.004], and the difference remained significantly after controlling for age and gender [OR (95 % CI) = 5.34 (1.47-19.39), P = 0.011). The G(del)G in the haplotype includes rs1799809|rs199469469|rs2069928 was of a significantly difference (P = 0.016) among PE patients and the controls, and remained significant (P = 0.015) after adjustment for age and sex. Our study reports that PROC SNPs (rs199469469) might be associated with PE susceptibility, with the G allele of rs199469469 serving as the protective factors for incidence of PE. These findings may contribute to the understanding and primary prevention of PE.

Characteristics and Risk Factors for Type 2 Endoleak in an East Asian Population From a Japanese Multicenter Database

BACKGROUND

Clinically distinct differences exist between East Asian and Caucasian subjects, but data for type 2 endoleak (T2EL) are limited in the East Asian population. The aim of this study was to analyze the characteristics of East Asian T2EL using a Japanese multicenter database.

METHODS AND RESULTS

Retrospective analysis of 832 endovascular aneurysm repairs performed from 2008 to 2014 were conducted. T2EL was observed in 234 cases (28.1%), and in 32 cases (3.8%) it led to sac expansion >5 mm caused by isolated T2EL (median follow-up, 35.6 months). On univariate and multivariate analysis, non-smoker status (odds ratio [OR], 2.216; P<0.001), Excluder stent graft (OR, 2.027; P<0.001), and T2EL at final angiogram (OR, 2.080; P<0.001) were risk factors for T2EL. On multivariate analysis for isolated T2EL with sac expansion, only non-smoker status remained (OR, 2.671; P<0.001). Other than T1EL, isolated T2EL was the most significant risk factor for sac expansion (OR, 18.486; P<0.001). Furthermore, out of 11 transarterial embolization procedures initiated, 4 led to rupture during follow-up.

CONCLUSIONS

East Asian T2EL had a strong relationship with non-smoker status. Also, T2EL was a significant risk factor for sac expansion, which sometimes led to rupture even after intervention. Along with the high prevalence of T2EL observed, East Asian T2EL may not always be benign.

Thrombotic risk factors in Chinese nonmalignant and noncirrhotic patients with portal vein thrombosis: an observational study with a systematic review of the literature

BACKGROUND

Until now, no data on the routine screening for thrombotic risk factors in Chinese nonmalignant and noncirrhotic patients with portal vein thrombosis (PVT) have been reported.

METHODS

A total of 141 nonmalignant and noncirrhotic patients with PVT who underwent screening tests for thrombotic risk factors between September 2009 and August 2012 were included in this study.

RESULTS

The JAK2 V617F mutation was found in 35 of the 141 patients tested. Neither the JAK2 exon 12 mutation nor the MPL W515 L/K mutation was found in any of the 50 patients tested. Overt myeloproliferative neoplasms (MPNs) were diagnosed in 13 patients (polycythemia vera, n=1; essential thrombocythemia, n=9; idiopathic myelofibrosis, n=3). Latent MPNs were considered in 23 patients with the JAK2 V617F mutation but without any significant abnormalities, as determined through regular blood tests. Anticardiolipin IgG antibodies were positive in none of the 136 patients tested. Paroxysmal nocturnal hemoglobinuria was not found in any of the 141 patients tested. Neither the factor V G1691A mutation nor the factor II G20210A mutation was found in any of the 72 patients tested. The C677T mutation in 5,10-methylenetetrahydrofolate reductase (MTHFR) was found in 29 of the 38 patients tested. Hyperhomocysteinemia was detected in eight of the 39 patients tested.

CONCLUSION

MPNs are an important thrombotic risk factor in Chinese patients with PVT. However, the extreme rarity of paroxysmal nocturnal hemoglobinuria, anticardiolipin IgG antibodies, and factor V G1691A and factor II G20210A mutations has precluded any support for the implementation of routine screening for these thrombotic factors in such patients. Additional case-control studies should confirm the role of the MTHFR C677T mutation and hyperhomocysteinemia in the pathogenesis of PVT.

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.

A Singapore perspective on the use of a short course of chemothromboprophylaxis in patients who underwent total knee arthroplasty

INTRODUCTION

There is considerable controversy regarding the best method to prevent venous thromboembolism. In 2008, the American College of Chest Physicians (ACCP) published specific guidelines recommending the use of ow-molecular-weight heparin or warfarin, and a target international normalised ratio of 2.0-3.0 for a duration of at least 7-10 days, after elective knee arthroplasties. Many orthopaedic surgeons believe that these recommendations are biased toward reducing deep venous thrombosis (DVT), but neglect the implicated possibility of a higher incidence of wound complications. In order to enable an objective evaluation of the fit of the ACCP recommendations to the needs of our local cohort of patients, we aimed to look at the incidence of DVT in our local population.

METHODS

This study was a prospective observational study involving existing local patients in Singapore General Hospital, Singapore, who underwent total knee arthroplasty (TKA) and were on a short course of chemothromboprophylaxis (< 7 days) after the operation. The incidence of DVT in patients was evaluated using DVT imaging 4-6 days after the operation and at one month after the operation.

RESULTS

In our study cohort, the prevalence of DVT during the period between postoperative Days 4 and 6 was 12% (11% were distal DVT and 1% was proximal DVT). Only 9% of the patients had DVT one month after the operation. Using chi-square analysis, we found that there was no significant increase in the number of DVT and pulmonary embolism cases 4-6 days and 1 month after the operation (p > 0.05).

CONCLUSION

Contrary to the ACCP guidelines, a short course of chemothromboprophylaxis post TKA, lasting no more than 7 days, is safe and adequate in the low-risk Asian population.

Deficiency of antithrombin and protein C gene in 202 Chinese venous thromboembolism patients

INTRODUCTION

Antithrombin and protein C gene deficiencies are commonly inherited risk factors for VTE patients. We aim to investigate the deficiency of these two gene in 202 Chinese patients with venous thromboembolism (VTE).

METHODS

Antithrombin activity (AT: A) and protein C activity (PC: A) were measured in 202 VTE patients, and for those with unexplainable low results, PCR and direct sequencing of the related genes were carried out.

RESULTS

Deficiency levels of antithrombin and protein C gene were found to be 2% and 8%, respectively. AT or PC hereditary deficiency can be found in 10% patients with VTE.

CONCLUSION

Protein C gene deficiency might be more prevalent than AT gene deficiency in Chinese VTE patients. Functional assay combined with genetic analysis is useful in the diagnosis of inherited defects in VTE patients.

Thrombotic risk factors in Chinese Budd-Chiari syndrome patients. An observational study with a systematic review of the literature

In Western countries, thrombotic risk factors for Budd-Chiari syndrome (BCS) are very common, including factor V Leiden mutation, prothrombin G20210A mutation, myeloproliferative neoplasms, paroxysmal nocturnal haemoglobinuria, etc. However, the data regarding thrombotic risk factors in Chinese BCS patients are extremely limited. An observational study was conducted to examine this issue. A total of 246 BCS patients who were consecutively admitted to our department between July 1999 and December 2011 were invited to be examined for thrombotic risk factors. Of these, 169 patients were enrolled. Neither factor V Leiden mutation nor prothrombin G20210A mutation was found in any of 136 patients tested. JAK2 V617F mutation was positive in four of 169 patients tested. Neither MPL W515L/K mutation nor JAK2 exon 12 mutation was found in any of 135 patients tested. Overt myeloproliferative neoplasms were diagnosed in five patients (polycythemia vera, n=3; essential thrombocythemia, n=1; idiopathic myelofibrosis, n=1). Two of them had positive JAK2 V617F mutation. Both CD55 and CD59 deficiencies were found in one of 166 patients tested. This patient had a previous history of paroxysmal nocturnal haemo-globinuria before BCS. Anticardiolipin IgG antibodies were positive or weakly positive in six of 166 patients tested. Hyperhomocysteinaemia was found in 64 of 128 patients tested. 5,10-methylenetetrahydrofolate reductase C677T mutation was found in 96 of 135 patients tested. In conclusion, factor V Leiden mutation, prothrombin G20210A mutation, myeloproliferative neoplasms, and paroxysmal nocturnal haemoglobinuria are very rare in Chinese BCS patients, suggesting that the etiological distribution of BCS might be different between Western countries and China.

Expression and functional characterisation of natural R147W and K150del variants of protein C in the Chinese population

Protein C is a vitamin K-dependent serine protease zymogen in plasma which upon activation to activated protein C (APC) by thrombin down-regulates the clotting cascade by limited proteolysis of the procoagulant cofactors Va and VIIIa. In addition to its anticoagulant activity, APC also exhibits potent cytoprotective and anti-inflammatory activities. While the anticoagulant activity of APC is enhanced by the cofactor function of protein S on membrane phospholipids, the cytoprotective intracellular signalling activity of APC requires complex formation with endothelial protein C receptor (EPCR) expressed on the vascular endothelium. Two natural variants of APC [Arg-147 to Trp substitution (R147W) and Lys-150 deletion (K150del)] have been identified in the Chinese population as hotspot mutants occurring with high frequencies of 27.8% and 13.9%, respectively, among 36 protein C-deficient subjects. The affected individuals exhibit variable thrombotic tendencies. To understand the underlying cause of the thrombotic phenotype in these patients, we expressed these two protein C variants in mammalian cells and characterised their anticoagulant and anti-inflammatory properties using established in vitro and cellular assays. Our results suggest that both R147W and K150del variants have normal amidolytic and proteolytic activities in the absence of cofactors. However, the R147W mutant exhibits ~3 times lower affinity for binding to EPCR and the K150del variant has ~2-3-fold impaired anticoagulant activity in the presence of protein S. These results provide some insight into the possible pathogenic mechanism of protein C deficiency in Chinese patients carrying these mutations.

Familial Budd-Chiari Syndrome in China: A Systematic Review of the Literature

Familial occurrence of Budd-Chiari syndrome (BCS) has been reported in scattered cases, which potentially favors the congenital theory. A review of the literature was conducted to demonstrate this phenomenon in China. PubMed, VIP, and CNKI databases were searched for studies describing at least two Chinese BCS patients from the same one family. In the 18 eligible papers, 30 siblings or first-degree relatives from 14 families were diagnosed with BCS at 9 different centers. Common clinical presentations included varices of abdominal wall and lower limbs, edema of legs, and ascites. Type and location of obstruction were similar among these patients from the same one family. Screening for BCS was conducted in 65 family members from 3 families, demonstrating that 2 asymptomatic siblings from one family were further diagnosed with BCS. Factor V Leiden mutation was found in 3 of 4 patients from one family and in one of 2 patients from another one family. Prothrombin G20210A gene mutation was found in none of the 4 patients from the 2 families. In conclusion, our study showed the possibility of familial aggregation in Chinese BCS patients, but these available data cannot support the previous hypothesis that familial BCS originates from congenital vascular malformation.

Activated protein C anticoagulant system dysfunction and thrombophilia in Asia

Thrombophilia that is common among Caucasians is caused by genetic polymorphisms of coagulation factor V Leiden (R506Q) and prothrombin G20210A. Unlike that in Caucasians, thrombophilia that is common in the Japanese and Chinese involve dysfunction of the activated protein C (APC) anticoagulant system caused by abnormal protein S and protein C molecules. Approximately 50% of Japanese and Chinese individuals who develop venous thrombosis have reduced activities of protein S. The abnormal sites causing the protein S molecule abnormalities are distributed throughout the protein S gene, PROS1. One of the most common abnormalities is protein S Tokushima (K155E), which accounts for about 30% of the protein S molecule abnormalities in the Japanese. Whether APC dysfunction occurs in other Asian countries is an important aspect of mapping thrombophilia among Asians. International surveys using an accurate assay system are needed to determine this.

PROC c.574_576del polymorphism: a common genetic risk factor for venous thrombosis in the Chinese population

BACKGROUND

There are ethnic differences in the genetic risk factors for venous thrombosis (VT). The genetic causes of VT in the Chinese population are not fully understood.

OBJECTIVES

To identify possible common abnormal factors that could contribute to thrombosis susceptibility.

METHODS/RESULTS

We measured the levels of nine types of plasma coagulation factor, three types of anticoagulation factor and two types of fibrinolytic factor in 310 VT patients. Factor V activity was higher in 32 cases. Eleven of the 32 cases also had low protein C (PC) or protein S (PS) activities, indicating PC or PS deficiency. No other abnormalities were observed in the other 21 cases. All of the samples were sensitive to activated PC inactivation. Therefore, the abnormal factor involved may be FV inactivator or its cofactor rather than FV itself. Resequencing identified a common PROC c.574_576del variant in 10 of the 32 subjects. In a case-control study, this variant was detected in 68 of the 1003 patients and in 25 of the 1031 controls. It had an adjusted odds ratio of 2.71 (95% confidence interval [CI] 1.68-4.36). PC amidolytic activities of most variant carriers were similar to those of non-carriers, but the mean anticoagulant activity was only 72.7 U dL(-1). Expression studies in vitro showed that the anticoagulant activity of the mutant PC was 43.6% of that of the wild-type PC.

CONCLUSIONS

We identified what is, so far, the most common genetic risk factor for VT in the Chinese population, with its prevalence being approximately 2.36%.

New quantitative total protein S-assay system for diagnosing protein S type II deficiency: clinical application of the screening system for protein S type II deficiency

Venous thromboembolism (VTE) incidence is rising rapidly in Japan with lifestyle westernization and aging. Deficiency of protein S, an important blood coagulation regulator, is a risk factor for VTE. Protein S deficiency prevalence in Asians is approximately 10 times that in Caucasians and that of protein S type II deficiency, associated with the protein S Tokushima mutation (K155E), is quite high in Japan. However, currently available methods for measuring protein S are not precise enough for detection of this deficiency. We developed a novel assay system for precise simultaneous determinations of total protein S activity and total protein S antigen level, using a general-purpose automated analyzer, allowing protein S-specific activity (ratio of total protein S activity to total protein S antigen level) to be calculated. Mean specific activity was 0.99 for samples from healthy individuals but 0.69 or less (mean-3SD) in protein S type II-deficient and warfarin-treated samples, but was 1.0 in an estrogen-treated sample with significantly decreased protein S antigen. Protein S gene analyses in healthy individuals with specific activity 0.69 or less revealed the K155E mutation in all three. These results show our new assay system to be an effective screening tool for protein S type II deficiency. This system can also be used in an automated analyzer, facilitating numerous sample measurements, and is, thus, applicable to regular medical checkups and diagnosing VTE. Such applications would potentially contribute to early detection of protein S type II deficiency, and, thereby, to thrombosis prevention.

Thrombophilia among Chinese women with venous thromboembolism during pregnancy

AIMS

To assess the prevalence of thrombophilia among Chinese women with venous thromboembolism (VTE) developed during pregnancy.

METHODS

Based on information from a tertiary teaching unit, all recorded cases of deep vein thrombosis (DVT) and pulmonary embolism (PE) during pregnancy diagnosed between 1997 and 2005, were assessed for prevalence of thrombophilia. Fifty-five healthy women, who had at least one normal pregnancy but without any previous history of VTE, were recruited as controls.

RESULTS

A total of 44 subjects completed thrombophilia screening, of whom 5 (11%) were confirmed to have thrombophilia [protein C (PC) deficiency (2), protein S (PS) deficiency (1), combined PC & PS deficiency (1) and antithrombin III deficiency (1)]. Homozygous 5,10-methylenetetrahydrofolate reductase (C677T) gene mutation was found in 6 (14%) subjects but not in the controls. There was no antiphospholipid syndrome, activated PC resistance, factor V Leiden or prothrombin gene mutations.

CONCLUSION

In the Chinese population, PS and PC deficiencies are common thrombophilia for VTE during pregnancy and thrombophilia screening should be recommended in all pregnant women who suffer from VTE.

Normal ranges and genetic variants of antithrombin, protein C and protein S in the general Chinese population. Results of the Chinese Hemostasis Investigation on Natural Anticoagulants Study I Group

BACKGROUND

Inherited deficiency of antithrombin, protein C and protein S, three important, naturally occurring coagulation inhibitors, might play a major role in the occurrence of venous thromboembolism in Chinese. The establishment of age- and gender-related normal ranges of these inhibitors is crucial for an accurate diagnosis of these deficiencies.

DESIGN AND METHODS

We designed a prospective cross-sectional study recruiting healthy adults from four university-affiliated hospitals in China. Antithrombin, protein C and protein S were studied by measuring their activity. Gene analysis was performed when natural anticoagulant deficiency was suspected. Polymorphisms of the factor V gene were searched for among subjects who were positive for activated protein C resistance.

RESULTS

In 3493 healthy Chinese adults (1734 men, 1759 women; age 17-83 years), we found higher age-adjusted activities for protein C and protein S in men than in women but no sex difference for antithrombin. In women, mean protein C and protein S activities increased with age. In men, mean protein C levels increased with age up to the age of 49 but decreased after 50 years old; mean protein S levels decreased after 50 years of age. Antithrombin levels remained stable over time in women but decreased significantly after 50 years of age in men. Reference values according to age and sex allowed the identification of 15 genetic variants (protein C:10, antithrombin:3, protein S:2) in subjects with protein activity below the 1(st) percentile.

CONCLUSIONS

This is the largest survey ever conducted in the healthy general Chinese population. These normal ranges provide the essential basis for the diagnosis and treatment of thrombosis in Chinese.