Coagulation Status and Venous Thromboembolism Risk in African Americans: A Potential Risk Factor in COVID-19.

Severe acute respiratory syndrome coronavirus 2 infection (COVID-19) is known to induce severe inflammation and activation of the coagulation system, resulting in a prothrombotic state. Although inflammatory conditions and organ-specific diseases have been shown to be strong determinants of morbidity and mortality in patients with COVID-19, it is unclear whether preexisting differences in coagulation impact the severity of COVID-19. African Americans have higher rates of COVID-19 infection and disease-related morbidity and mortality. Moreover, African Americans are known to be at a higher risk for thrombotic events due to both biological and socioeconomic factors. In this review, we explore whether differences in baseline coagulation status and medical management of coagulation play an important role in COVID-19 disease severity and contribute to racial disparity trends within COVID-19.

Primary Thrombophilia in Mexico XIII: Localization of the Thrombotic Events in Mexican Mestizos With the Sticky Platelet Syndrome.

The sticky platelet syndrome (SPS) is a common cause of both arterial and venous thrombosis, being a dominant autosomal disease with qualitative platelet alterations and familial occurrence. It is characterized by platelet hyperreactivity with increased platelet aggregability in response to low concentrations of platelet agonists: epinephrine, adenosine diphosphate, or both. The clinical manifestations involve venous or arterial thrombosis, recurrent pregnancy loss, and fetal growth retardation. To analyze the localization of the thrombotic episodes in a cohort of Mexican mestizo patients with SPS. Between 1992 and 2016, 86 Mexican mestizo patients with SPS as the single thrombophilic condition were prospectively identified; all of them had a history of thrombosis. There were 15 males and 71 females. The thrombotic episodes were arterial in 26 cases and venous in 60 (70%). Arterial thrombosis was mainly pulmonary thromboembolism, whereas venous thromboses were identified most frequently in the lower limbs. Mexican mestizo population with SPS is mainly female; the type I of the condition is the most frequent; both arterial and venous thrombosis can occur, and they are mainly pulmonary embolism and lower limbs venous thrombosis, respectively.

Can thrombophilia worsen maternal and perinatal outcomes in cases of severe preeclampsia?

OBJECTIVE: To evaluate whether thrombophilia worsens maternal and foetal outcomes among patients with severe preeclampsia (PE). METHOD: From October 2009 to October 2014, an observational retrospective cohort study was performed on pregnant women with severe PE diagnosed before 34 weeks of gestation and their newborns hospitalized at the Clinics Hospital, FMUSP. Patients who had no heart disease, nephropathies, pre-gestational diabetes, gestational trophoblastic disease, foetal malformation, or twin pregnancy and who underwent thrombophilia screening during the postnatal period were included. New pregnancies of the same patient; cases of foetal morphological, genetic, or chromosomal abnormalities after birth; and women who used heparin or acetylsalicylic acid during pregnancy were excluded. Factor V Leiden, G20210A prothrombin mutation, antithrombin, protein C, protein S, homocysteine, lupus anticoagulant, and anticardiolipin IgG and IgM antibodies were analysed. The groups with and without thrombophilia were compared regarding their maternal clinical and laboratory parameters and perinatal outcomes. RESULTS: Of the 127 patients selected, 30 (23.6%) had thrombophilia (hereditary or acquired). We found more white patients in thrombophilia group (p = .036). Analysis of maternal parameters showed a tendency of thrombophilic women to have more thrombocytopenia (p = .056) and showed worsening of composite laboratory abnormalities (aspartate aminotransferase ≥ 70 mg/dL, alanine aminotransferase ≥ 70 mg/dL, platelets < 100,000/mm3, serum creatinine ≥ 1.1 mg/dL; p = .017). There were no differences in foetal perinatal outcomes. CONCLUSION: The presence of thrombophilia leads to worsening of maternal laboratory parameters among patients with severe forms of PE but without worsening perinatal outcomes.

Prevalence of common hereditary risk factors for thrombophilia in Somalia and identification of a novel Gln544Arg mutation in coagulation factor V.

Thrombophilia, commonly manifested as venous thromboembolism (VTE), is a worldwide concern but little is known on its genetic epidemiology in many parts of the globe particularly in the developing countries. Here we employed TaqMan genotyping and pyrosequencing to evaluate the prevalence of known common nucleotide polymorphisms associated with thrombophilia in a Somali population in the Puntland region of Somalia. We also employed next generation sequencing (NGS) to investigate other genetic variants in a Somali patient with deep venous thrombosis (DVT). As expected, we found no existence of factor V Leiden (rs6025) and prothrombin G20210A (rs1799963) in the Somali population. The G allele of ABO [261G/delG] polymorphism (rs8176719) was found at a frequency of 29%, similar to that observed in other African populations. We found the lowest so far reported frequency of MTHFR C677T (rs1801133) polymorphism in the Somali population (T allele frequency 1.5%). A novel and deleterious single nucleotide variation in exon 11 of coagulation factor V (c.1631A>G) causing Gln544Arg exchange in factor V was identified in a 29 years old Somali female with DVT. The same patient was heterozygous to VKORC1 Asp36Tyr polymorphism (rs61742245) that predisposes to warfarin resistance. In conclusion, this study shows that common hereditary factors for thromboembolism found in Caucasians are either less frequent or absent in the Somali population-similar to the situation in other Africans. NGS is possibly a better choice to detect genetic risk variants for thrombosis in this ethnic group.

Global prevalence of prothrombin gene mutation G20210A and implications in women's health: a systematic review.

Distribution of hereditary thrombophilic gene mutations differs globally. Prothrombin gene mutation G20210A is a common prothrombotic single-nucleotide polymorphism. In this systematic review, we provide a comprehensive report of the prevalence of prothrombin G20210A across the globe. Databases [Pubmed, Web of Science, Embase] were interrogated from their inception through December 2015 for articles reporting prothrombin G20210A prevalence rates and ethnicity. Prevalence rates were organized by continent and ethnoracial ancestry. A total of 113 articles were included with a total 61 876 participants tested for prothrombin G20210A. Reported prevalence rates varied from 0 to 15.9% among ethnic groups, with higher rates seen in the thromboembolism affected cohort compared with the unaffected cohort. Carrier rate distribution is supported by known historical migration patterns of global populations. This review of prothrombin G20210A prevalence may guide resourceful screening for identification of hereditary thrombophilia in female populations of interest with hypercoagulable states.

Primary thrombophilia in Mexico: a single tertiary referral hospital experience.

Thrombophilia is a complex hypercoagulable state that increases the risk of thrombosis. Most reports in medical literature of the Mexican population with this disease lack statistical validity. Therefore, the aim of this study is to describe the prevalence of primary thrombophilia in a tertiary referral hospital in Mexico. This is a study of patients referred to our hospital because of a hypercoagulable state and who later on were diagnosed with primary thrombophilia. The thrombophilia workup included methylenetetrahydrofolate reductase (MTHFR) C677T, antiphospholipid antibodies, protein C, protein S, antithrombin, factor VIII, factor V Leiden, prothrombin mutation G20210A, activated protein C resistance, JAK2 V617F and homocysteine. Ninety-five individuals were tested. The MTHFR C677T polymorphism was the most frequent anomaly in 84.1% of the tested individuals. There was a relatively low prevalence of factor V Leiden (5.2%) and anticoagulant protein deficiency (8.3%). The MTHFR C677T polymorphism has a very high prevalence compared with the low prevalence of anticoagulant protein deficiency and factor V Leiden mutation in Mexicans.

Ethnic differences in the association of thrombophilic polymorphisms with obstetric complications in Slovak and Roma (Gypsy) populations.

AIMS: Hereditary as well as acquired thrombophilia is associated with a higher incidence of severe obstetric complications such as preeclampsia, spontaneous pregnancy loss, placental abruption, and fetal growth retardation. The aim of our study was to examine the association of selected thrombophilic polymorphisms (factor V Leiden, MTHFR C677T, and MTHFR A1298C) with pregnancy complications in the Slovak majority population and the Roma (Gypsy) ethnic population. The study included 354 women; 120 patients and 105 controls from the Slovak majority population, 50 patients and 79 controls from the Slovak Roma population. Genotyping was performed by the real-time polymerase chain reaction method using TaqMan(®) MGB probes. RESULTS: A statistically significant higher frequency of factor V Leiden (p=0.001, odds ratio [OR]=5.9) and MTHFR C677T polymorphism (p=0.011, OR=1.7) was observed in the Slovak majority patient group compared to the control group. The incidence of MTHFR A1298C polymorphism between patients and controls did not differ significantly. None of the three polymorphisms studied was in association with pregnancy complications in the group of Roma women. CONCLUSIONS: Our study has confirmed the variable distribution of selected thrombophilic polymorphisms in different ethnic groups as well as their various effects on the clinical phenotype.

Haemostatic factors, lipoproteins and long-term mortality in a multi-ethnic population of Gujarati, African-Caribbean and European origin.

OBJECTIVES: To examine the relations between haemostatic factors and lipoproteins with mortality in British Europeans, African-Caribbeans (AfC) and Gujarati Indians. METHODS: A prospective cohort study of 331 subjects (40-79 years), followed-up over 26 years for mortality. Apolipoprotein-A1 (Apo-A1), apolipoprotein-B (Apo-B), factor VII coagulant activity (FVIIc), fibrinogen and von Willebrand Factor (vWF) were measured at baseline in 118 Europeans, 100 AfC and 113 Gujaratis. Aortic pulse wave velocity (aPWV) was measured in 174 participants. RESULTS: 147 (44.4%) subjects died during a median of 24 years follow-up with 69 cardiovascular deaths. Women at baseline had higher, and AfC males the lowest FVIIc and Apo-A1 levels. Baseline age-sex and ethnicity adjusted FVIIc levels were higher in those who died (131.0 vs. 117.4%; P = 0.048). In similarly adjusted partial correlations, Apo-A1 was inversely related to arterial stiffness (ρ = -0.23, P = 0.04). Over the 26 years follow-up, participants below the median (i.e. with lower concentration) of FVIIc, Fibrinogen, Apo-B and vWF had better survival rates than those with higher concentrations; those with higher concentrations of Apo-A1 had better survival. In Cox multivariable regression analyses including sex, ethnicity and aPWV, independently increased risk of all-cause mortality came only from SBP (per 5 mmHg); P = 0.011), age (per year); P < 0.0001 and FVIIc at 7% (per 10-unit; HR 1.07 (1.02, 1.12); P = 0.008. Separately, Apo-A1 (HR 0.12 (0.02, 0.75; P = 0.029) was independently associated with a very significant 88% reduction in all-cause mortality. CONCLUSIONS: Despite a relatively small sample size, long-term follow-up suggests an independent effect of the prothrombotic state (via FVIIc) and apo-A1 (a constituent of HDL) on mortality.

Blood pressure measurement reliability among different racial-ethnic groups in a stroke prevention study.

OBJECTIVE: High blood pressure (BP) is commonly not diagnosed, and patients do not achieve target values when treated. Among 20,000 patients encompassing most races-ethnicities, we evaluated BP measurements and treatment response in a stroke prevention trial. Our goal was to identify BP measurement differences between clinical trial and patient determinations and among the racial-ethnic groups. MATERIALS AND METHODS: A total of 20,332 patients with ischemic stroke were randomized to receive antiplatelet treatment and 80 mg of telmisartan versus placebo. BP measurements were obtained at the first clinic visit and then 1 and 3 months later and every 6 months thereafter. One week after the first clinic visit, patients were requested to report a BP measurement obtained elsewhere. Measurements at the trial clinics were obtained with the same electronic device. Statistical analysis was used to detect significant differences. RESULTS: The mean patient age was 66 years; 36% were women, and race-ethnicity comprised 58% Whites, 33% Asian, 4.9% Hispanic, and 4% Black. Overall, 74% of patients were hypertensive. BP varied between the race-ethnicity groups, being highest in Hispanics (145/85) and lowest in Blacks (144/82). BP at visits clinic 1, nonclinic 1A, and clinic 2 were, respectively, 144/84, 137/80, and 139/81 mmHg, with the difference between visits 1-2 and visit 1A being significant. BPs were normal in 42% of the cases at visit 1A, and of these, only 44% were normal at visit 1 and 57.6% were normal on visit 2. Similar findings were noted for all race-ethnicity groups. CONCLUSION: BP values varied among race-ethnicities and showed differences between clinic and patient measurements. This finding questions the reliability of self-reported BP and has implications for BP management in daily clinical practice.

Paroxysmal Nocturnal Hemoglobinuria is rare cause for thrombosis of the intra-abdominal veins in the ethnic Indian population - results from FLAER-based flowcytometry screening.

BACKGROUND: Paroxysmal nocturnal hemoglobinuria (PNH) may present as cytopenia, hemolysis, or thrombosis at unusual sites including splanchnic vessels. Thrombosis of the portal veins and hepatic veins are associated with thrombophilic risk factors: deficiencies of protein C, protein S, and antithrombin, positivity for antiphospholipid antibodies, and factor V Leiden mutation. There is limited information regarding PNH presenting primarily as a thrombotic event. We prospectively screened 142 consecutive patients with intrabdominal thrombosis and 106 controls with fluorescently labeled inactive toxin aerolysin (FLAER)-based flowcytometry to assess the frequency of PNH as a thrombophilic risk factor in patients with intra-abdominal thrombosis. METHODS: Granulocytes of patients and controls were screened with CD 24 and FLAER and monocytes with CD 14 and FLAER. Dual negativity of >1% events in both lineages was interpreted as a positive PNH clone. Screening for thrombophilia risk factors was carried out. RESULTS: Two (1.4%) cases had large PNH clones. RBC also demonstrated the PNH defect. Thrombophilia risk factors were as follows: deficiency of protein S, protein C, and antithrombin in 13.4%, 4.9%, and 2.1%, respectively, and positivity for anti-beta-2 glycoprotein 1, anticardiolipin antibodies, and lupus anticoagulant in 9.2%, 1.4%, and 0.7%, respectively. Factor V Leiden mutation was seen in 1.4% patients. CONCLUSION: PNH was uncommon in patients with intra-abdominal thrombosis in the ethnic Indian population. Despite low positivity, screening by flowcytometry for PNH is of value in this group of patients because it provides an opportunity to rapidly establish the diagnosis of this treatable disorder, which might otherwise be missed if the initial presentation is only thrombotic.

Association between prothrombin gene polymorphisms and hereditary thrombophilia in Xinjiang Kazakhs population.

To assess the association between polymorphisms of prothrombin gene and hereditary thrombophilia in Xinjiang Kazakhs population. Through cross-sectional investigation, permanent Kazakh population of Ili Kazakh Autonomous Prefecture was selected as the study object to measure their antithrombin III (AT-III), protein C, protein S activity and activated C protein resistance value, thus defining the situation of the crowd's hereditary thrombophilia. Sequenom Massarray detection technology was used to conduct a genotype test of the six sites selected by the case and control groups. Haploview software was used to perform linkage disequilibrium analysis of the six sites, and the impact of the interaction between genetic variations and environment on hereditary thrombophilia was researched by the use of sum model. A total of 1005 Kazakh volunteers participated in the test (332 men and 673 women), average age (41.13 ±â€Š11.50) years; the prevalence of hereditary thrombophilia in Xinjiang Kazakh population was 31.0%, and the prevalence of AT-III deficiency, protein C deficiency, protein S deficiency and activated protein C resistance was 16.4, 14.9, 20.6 and 7.8%, respectively. The difference in allele frequency of the hereditary thrombophilia patient group at rs3136447 and rs5896 sites was statistically significant (P = 0.0483 and P = 0.0302, respectively). rs5896 and rs2070852 had high linkage disequilibrium (r = 0.99), and constituted a single-domain block 1. The rs3136447 and the rs5896 polymorphisms located in the region of the prothrombin gene may be associated with hereditary thrombophilia in the Xinjiang Kazakhs population. There is additive interactive effect of rs5896 polymorphism (CT + TT) and smoke on hereditary thrombophilia.

Polymorphisms in Factor II and Factor V thrombophilia genes among Circassians in Jordan.

Thrombosis is a major cause of morbidity and mortality worldwide. Genetic factors are one component of thrombosis. We studied the prevalence of two mutations that are known risk factors in the pathogenesis of arterial and venous thrombosis in the genetically isolated Circassian population in Jordan. Factor II G20210A and Factor V Leiden single nucleotide polymorphisms were analysed by polymerase chain reaction and restriction fragment length polymorphism method in 104 random unrelated subjects from the Circassian population in Jordan. The prevalence rates among the Circassian population in Jordan for Factor II G20210A was 12.2% and for Factor V Leiden was 7.7%. We have shown that the population is in Hardy-Weinberg equilibrium and that the prevalences of both mutations are within the range of other ethnic groups. This is the first study to describe Circassian health related genetic characteristics in Jordan. Such population-based studies will contribute to understanding the interaction between genetic and environmental risk factors. It will remain to be seen whether carriers of Factor II G20210A and Factor V Leiden are more likely to develop thrombosis. This issue should be studied in the future to determine the need for screening of these mutations particularly in thrombophilia patients.

Genetic thromobophilia in pregnancy: a case-control study among North Indian women.

In the present study, an attempt is made to understand the role of genetic thrombophilias i.e. MTHFR C677T and FVL in the causation of various pregnancy complications like pregnancy induced hypertension (PIH), recurrent abortions, intra-uterine growth retardation (IUGR) and intra-uterine death on the whole and also individually along with the comparative assessment of pathophysiological basis of various pregnancy complications via the genetic proximities. One thousand and eleven (1,011) women of reproductive age group were recruited in the present study comprising various complications and controls. Recruitment criteria for all the pregnancy complications and controls was made and followed strictly. MTHFR C677T and FVL mutation detection was done in all the subjects. Vegetarianism was found to be significant risk factors for all the pregnancy complications and also when assessed individually. With respect to MTHFR C677T polymorphism, higher frequency of 677T allele was found among controls as compared to cases. 677T allele was found to pose decreased risk for various pregnancy complications on the whole and also individually. On adjusting the diet, regression analysis revealed no risk of mutant allele (T) for various pregnancy complications. FVL homozygous mutants were found to be absent among controls. In conclusion, the present study depicts dietary pattern as one of the most important factors in demonstrating the role of MTHFR C677T in various pregnancy complications and is indicative of a relatively deleterious effect of double dose of FVL in the presently studied population. Additionally, these polymorphisms play an important role in the orchestration of PIH to IUGR and vice versa.

African-Caribbean ethnicity is associated with a hypercoagulable state as measured by thrombin generation.

African-Caribbean ethnicity is associated with an increased risk of both first and recurrent venous thromboembolism (VTE). The aim of this study was to evaluate thrombin generation in African-Caribbeans compared with whites in patients with deep vein thrombosis (DVT) and healthy volunteers. Thrombin generation was measured in a case-control study of 80 patients who had completed anticoagulation therapy for a first DVT (50 white and 30 African-Caribbean) and 66 controls. Peak thrombin with and without thrombomodulin was significantly higher in African-Caribbeans with DVT compared with whites with DVT (P < 0.001 for both comparisons) and African-Caribbean controls (P < 0.001, 0.003, respectively). Endogenous thrombin potential (ETP) with and without thrombomodulin was significantly higher in African-Caribbeans with DVT than whites with DVT (P ≤ 0.001 for both comparisons). Maximum velocity and ETP ratio were increased in African-Caribbeans with DVT compared with whites with DVT (P < 0.001 and 0.030, respectively) and African-Caribbean controls (P < 0.001 and 0.019, respectively). Within the control group, peak thrombin was significantly increased in African-Caribbeans compared with whites (P = 0.017). ETP, peak thrombin with thrombomodulin and maximum velocity were also increased in African-Caribbeans compared with white controls (P = 0.045 for all comparisons). African-Caribbeans with DVT had significantly higher factor VIII levels compared with whites with DVT and controls. African-Caribbean ethnicity confers a hypercoagulable state as measured by thrombin generation. This supports epidemiological findings of increased risk of first and recurrent VTE. Thrombin generation requires adjustment for ethnicity in studies undertaken in ethnically diverse populations.

Janus kinase (JAK) 2 V617F mutation in Asian Indians with cerebral venous thrombosis and without overt myeloproliferative disorders.

It is unclear whether the somatic JAK2V617F mutation, a marker for chronic myeloproliferative disorders (MPDs), is associated with cerebral venous thrombosis (CVT) in the absence of MPD. Our aim was to determine the prevalence and association of the JAK2V617F mutation among patients with CVT and without overt MPD. We investigated 372 CVT patients without features suggestive of MPD and 383 age- and gender-matched healthy controls, for the JAK2V617F mutation. Genotyping was done by polymerase chain reaction and restriction fragment length polymorphism. The heterozygous JAK2V617F mutation was present in 22 of 372 patients (5.9%) and 2 of 383 controls (0.5%). Logistic regression analysis showed this mutation to be an independent predictor of CVT after adjusting for the conventional risk factors (adjusted odds ratio: 5.47, 95% CI: 1.06-28.27, p=0.04). The mutation was more prevalent in men (p=0.005). Patients with JAK2V617F mutation were older (p=0.036), and had higher mean hemoglobin level (p<0.0001) than those without the mutation. Smokers with the mutation had 9.45-fold increased risk of CVT compared to non-smokers without the mutation (OR: 9.45, 95% CI: 1.17-76.02, p<0.0001). We conclude that the JAK2V617F mutation could contribute to increased risk of CVT in Indians. Larger studies in other ethnic populations are warranted before considering the inclusion of the JAK2V617F gene polymorphism into the routine diagnostic workup of CVT.

Frequency of thrombophilic genetic polymorphisms among Saudi subjects compared with other populations.

Thrombophilic mutations increase the tendency toward thromboembolic disease. The aim of this study was to estimate the prevalence of the genetic variants related to thrombophilia among Saudis compared with other populations. Real-time polymerase chain reaction (PCR) genotyping was carried out to determine the polymorphic variants of factor V Leiden 1695G/A, prothrombin 20210G/A, plasmin activator inhibitor 1 4G/5G, methylene tetrahydrofolate reductase (MTHFR) 677C/T, MTHFR 1298A/C, and angiotensin-converting enzyme (ACE) insertion/deletion (I/D) among a representative sample of healthy Saudi subjects. Carraige rate for each of the mutant variants of factor V Leiden (FVL) and FII genes constituted 2% of the surveyed subjects giving an allele frequency of 0.01, homozygous forms of plasminogen activator inhibitor-1 (PAI-1) gene 4G/4G, MTHFR 677TT, 1298CC, and ACE DD were present among 7.7, 2.55, 7, and 51.8% of subjects with a mutant allele frequency of 0.4, 0.19, 0.29, and 0.73, respectively. This study showed that the Saudi population has a peculiar pattern regarding thrombophilic mutations that might warrant additional considerations for prophylaxis.

The frequency of factor V Leiden and prothrombin G20210A mutations in Slovak and Roma (Gypsy) ethnic group of Eastern Slovakia.

Factor V Leiden and prothrombin G20210A are the two most prevalent causes of inherited thrombophilia. The prevalence of these mutations varies widely in healthy Caucasian population. The aim of our study was to determine the frequency of factor V Leiden and prothrombin G20210A mutations in Slovak and Roma ethnic group from Eastern Slovakia. We analyzed 540 asymptomatic individuals (269 individuals of Slovak ethnicity and 271 individuals of Roma ethnicity) by real-time PCR method. The detected allele frequencies were 2.97 versus 6.64 % for factor V Leiden (p = 0.0049), and 0.74 versus 0.92 % for prothrombin mutation (p = 0.7463) in Slovak and Roma population, respectively. The Roma ethnic group had significantly higher prevalence of factor V Leiden mutation when compared to Slovak ethnic group. The allele frequency of factor V Leiden in ethnic Romanies from Eastern Slovakia was one of the highest in Europe. Our results confirm an uneven geographical and ethnic distribution of factor V Leiden.

Accuracy assessment of pharmacogenetic algorithms for warfarin dose prediction in Chinese patients.

A few warfarin pharmacogenetic dosing algorithms have been proposed,based on multiethnic or homogeneous populations, to estimate warfarin therapeutic doses. However, it remains to be proven that which algorithm is accurate in predicting warfarin dose in Chinese people. We selected eight warfarin dose predictive pharmacogenetic algorithms and retrospectively assessed the predictive accuracy of each algorithm in a total of 368 eligible outpatients by comparing the actual stable therapeutic dose to the dose predicted by the algorithm. Our results showed that a high level of performance was demonstrated by three algorithms,Gage et al., Anderson et al., and Wu et al., having a similar performance in coefficient of determination (R2) and percentage of patients predicted dose within 20% of actual dose. The Gage et al. algorithm had the lowest mean absolute error (MAE). These results indicated that the algorithm by Gage et al. provided a more accurate prediction than did the others,which suggests that this pharmacogenetic algorithm might be used in clinical practice to guide rational administration of warfarin.