Immobility due to COVID-19 confinement, use of contraceptives and presence of the G20210A mutation. Validity of the Virchow triad for the presentation of Deep Venous Thrombosis and Pulmonary Thromboembolism.

Venous thromboembolic disease is a complex and multifactorial pathology, the result of the interaction of both genetic and environmental factors. The Virchow triad, first described in 1859, is still valid to explain the pathogenesis of thrombosis, where three main factors are reflected: a) hypercoagulable state; b) impaired blood flow; c) endothelial injury. The outbreak of a new COVID-19 pandemic has led to drastic confinement measures, with the consequent syndrome of immobility, as occurred in Spain between the months of March to June 2020. Pregnancy and hormonal contraception have proven to be an environmental factor predisposing to venous thrombosis. The presence of genetic factors, such as the mutation of the prothrombin gene G20210A, has been shown to be a risk factor for the presentation of venous thrombosis. We present the case of a 23-year-old non-smoking woman, a heterozygous carrier of a prothrombin gene mutation G20210A (hypercoagulability), who after confinement due to COVID-19 (impaired blood flow due to immobility) and use of hormonal patch contraceptives (endothelial abnormality), triggered deep vein thrombosis (DVT) / pulmonary thromboembolism (PE) that required hospital admission; and who, after rapid withdrawal of anticoagulant treatment, presented a second and a third episode of DVT. We highlight the usefulness of evaluating risk factors in G20210A heterozygous patients and the proper management of anticoagulation to avoid recurrences in patients susceptible to DVT / PE.

Immobility due to COVID-19 confinement, use of contraceptives and presence of the G20210A mutation. Validity of the Virchow triad for the presentation of Deep Venous Thrombosis and Pulmonary Thromboembolism.

Venous thromboembolic disease is a complex and multifactorial pathology, the result of the interaction of both genetic and environmental factors. The Virchow triad, first described in 1859, is still valid to explain the pathogenesis of thrombosis, where three main factors are reflected: a) hypercoagulable state; b) impaired blood flow; c) endothelial injury. The outbreak of a new COVID-19 pandemic has led to drastic confinement measures, with the consequent syndrome of immobility, as occurred in Spain between the months of March to June 2020. Pregnancy and hormonal contraception have proven to be an environmental factor predisposing to venous thrombosis. The presence of genetic factors, such as the mutation of the prothrombin gene G20210A, has been shown to be a risk factor for the presentation of venous thrombosis. We present the case of a 23-year-old non-smoking woman, a heterozygous carrier of a prothrombin gene mutation G20210A (hypercoagulability), who after confinement due to COVID-19 (impaired blood flow due to immobility) and use of hormonal patch contraceptives (endothelial abnormality), triggered deep vein thrombosis (DVT) / pulmonary thromboembolism (PE) that required hospital admission; and who, after rapid withdrawal of anticoagulant treatment, presented a second and a third episode of DVT. We highlight the usefulness of evaluating risk factors in G20210A heterozygous patients and the proper management of anticoagulation to avoid recurrences in patients susceptible to DVT / PE.

The Association Between Parameters of Erythrocytes Morphology and Thrombophilia-Related Mutations

Background: Alterations in erythrocyte morphology parameters have been identified and associated with hematological disorders and other chronic and cardiovascular diseases. Erythrocytes are abundant in thrombus content. Their hemoglobin density and differences in the ratio of macrocytic and microcytic cells may be associated with hypercoagulopathy in those with a history of thrombosis. Objective: This cross-sectional study aimed to investigate the relationship between hemogram parameters and thrombophilia genetic parameters. Method: A total of 55 patients whose thrombophilia panel was reviewed due to the diagnosis of thrombosis were included in the study. %MIC, %MAC, %HPO, %HPR and all hemogram parameters were measured using Abbott Alinity HQ. Prothrombin G20210A, MTHFR C677T, MTHFR A1298C, Factor V Leiden G169A and PAI-1 4G/5G mutations were studied using Real Time-PCR. Results: The MTHFR C677T mutation was detected in 58.2% of the patients. The Factor V Leiden mutation was detected in 5.5% of the patients. The MTHFR A1298C mutation was detected in 58.2%, The PAI mutation was detected in 74.5%, and the Factor 13 mutation was detected in 29% of the patients. Prothrombin G20210A mutation was not detected in any of the patients. Red blood cell (RBC) and Hct values were higher in Factor 13 mutant group; the Hgb and Htc values were higher in the MTHFR C677T mutant group. Conclusion: The MTHFR C677T and Factor 13 mutations may be associated with high Hct and RBC, Hgb, and Htc values, respectively and coagulation tendency in patients with a history of thrombosis.

The Factor II (FII) Expression Quantitative Trait Locus (eQTL) Prothrombin G20210A Is Pleiotropically Associated with Plasma Fibrinogen Levels and Has a Profound Effect on Obesity in Mexican Americans of South Texas

The literature on risk factors for venous thromboembolism (VTE) is replete with complex combinations of genetic and environmental determinants. Here we apply statistical genetic models to data from Mexican Americans of South Texas participating in the San Antonio Family Study (SAFS) to help disentangle some of this complexity. The SAFS has data for nearly 50 large extended pedigrees (Figure A) that are extensively phenotyped, especially for traits related to the pathophysiology of cardiovascular disease. Using a linear mixed model approach, while accounting for age, sex, and their interactions (including age-squared, age-by-sex, and age-squared-by-sex) as confounders, we found significant heritability for plasma FII (46%; N=640; p=6.9E-12) and fibrinogen (28%; N=759; p=1.6E-06) coagulant activity levels and that the Prothrombin G20210A mutation was significantly associated with both traits (FII: p=0.002; fibrinogen: p=0.037; Figure B). We also examined a dichotomous obesity variable based on the Adult Treatment Panel III criterion of sex-specific waist circumferences (>102 cm in males; >88 cm females) denoted as OBWC. Under a threshold and liability model, we found a significant heritability of the liability of OBWC (71%; N=654; p=4.4E-08) and that Prothrombin G20210A was a significant predictor (p=0.031), while still adjusting for age, sex, and their interactions. As can be seen in Figure C, the G20210A mutation profoundly impacts the liability of OBWC such that obesity prevalence, where the prevalence parameter is denoted by Kp in the figure, increases by 27% from individuals homozygous for the major G-allele (G/G) with a prevalence of 34% to heterozygous (G/A) individuals with a prevalence of 61%. To the best of our knowledge, this appears to be the largest single-allele-dose effect for obesity reported in the literature. We next performed bivariate trait analysis (each time accounting for age, sex, and their interactions as confounders) to discover potentially meaningful correlations between the three traits of interest and to see if these would influence their association with G20210A. Under a bivariate model for any two traits, denoted as trait A and B say, the parameters of the following equation are estimated: r_p(A,B) = r_g(A,B)*sqrt(h2_A)*sqrt(h2_B) + r_e(A,B)* sqrt(1-h2_A)*sqrt(1-h2_B), where r_p(A,B), r_g(A,B), and r_e(A,B) respectively denote the phenotypic, genetic, and environmental correlation coefficients of A and B, and where h2_A and h2_B denote the trait heritabilities. Moreover, we can test their significance using likelihood-based inferential statistics. For the FII and OBWC bivariate analysis, none of the correlation coefficients were significant. For the fibrinogen and OBWC bivariate analysis, we found significant phenotypic (r_p=0.24; p=2.0E-05) and genetic (r_g=0.41; p=0.024) correlations. For the FII and fibrinogen bivariate analysis, we found significant phenotypic (r_p=0.26; p=3.1E-10) and environmental (r_e=0.28; p=0.003) correlations. For all bivariate analyses, the Prothrombin G20210A mutation was always a significant predictor for both traits of any given pair. In conclusion, Prothrombin G20210A is pleiotropically associated with plasma FII and fibrinogen coagulant activity levels, and OBWC, and profoundly impacts the prevalence of obesity in our sample. The associations of the prothrombin G20210A mutation are not affected by the consideration of inter-correlations between the three traits examined and thus appears to be fairly robust. Figure 1 Figure 1. Disclosures DeFronzo: AstraZeneca: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees; Boehringer-Ingelheim: Membership on an entity's Board of Directors or advisory committees, Research Funding; Intarcia: Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding.

Cerebral venous sinus thrombosis: a complication of nitrous oxide abuse

Nitrous oxide (NO) is an inhalant that has become increasingly popular as a recreational drug. While it is presumed to be harmless, a number of adverse effects of NO have been described. We discuss the case of a 24-year-old man with no medical history, who initially presented to the emergency department with progressive polyneuropathy caused by vitamin B12 deficiency after NO abuse. Two days after being discharged with hydroxocobalamin supplementation, the patient returned with a severe headache, blurry vision and slurred speech. Imaging revealed cerebral venous sinus thrombosis. Hypercoagulability workup showed slightly elevated homocysteine and normalised vitamin B12 after supplementation. Genetic testing showed a heterozygous prothrombin G20210A mutation. He was treated with low-molecular-weight heparin followed by dabigatran. We hypothesise that NO use may increase the risk of developing cerebral venous thrombosis, especially in patients with multiple risk factors and elevated homocysteine levels.

Pregnancy complications in G20210A mutation carriers associated with high prothrombin activity

Objective To study the association between high activity of Factor II (prothrombin) in blood plasma with G20210A mutation and the development of great obstetrical syndromes. Material and methods A prospective clinical cohort study was conducted on 290 pregnant women (average age 31.7 ± 4.7 years old). The main group was made up of 140 G20210A patients, while the control group comprised 150 women with the wild G20210G type. The aim was to evaluate the activity of Factor II in the venous blood plasma during the stages of pregnancy with regard to trophoblast invasion waves. As per results, association analysis of Factor II activity value and gestational complications was carried out. Results In the control group, the median (Me) of Factor II activity ranged from 108% (preconception period) to 144% (pregnancy) [95% CI 130–150]. In patients with the GA type, the value was significantly higher in related periods, ranging from 149 to 181% [95% CI 142–195], p < 0.0001. With Factor II activity ranging from 148.5 to 180.6%, pregnancies in the main group had no complications. Higher levels of Factor II activity were associated with the development of early and/or severe preeclampsia (PE) and fetal growth retardation (FGR). Conclusion The data obtained regarding Factor II activity in blood plasma, juxtaposed with the development of great obstetrical syndromes, allow to assume that manifestation of G20210A in early and/or severe PE and FGR is associated with this coagulation factor’s level of activity. Threshold value of the Factor II activity with G20210A mutation, allowing to predict the development of PE, comprised 171.0% at the preconception stage (AUC – 0.86; p < 0.0001) and within 7–8 weeks of gestation it was 181.3% (AUC – 0.84; p < 0.0001).

Carrier frequencies for thrombophilia-related genetic variants in a Romanian cohort

Genetic testing for hereditary thrombophilia, an inherited predisposition to thrombotic events, is increasingly available. To evaluate the rate of positive thrombophilia tests in our laboratory we analyzed the carrier status for common thrombophilia-related gene variants in a consecutive unselected cohort of 360 Romanian patients. Genetic tests were performed on a Real-Time PCR platform. Majority of patients (98.6%) carried at least one thrombophilic variant. The carrier frequencies for classical prothrombotic mutations in F5 (Factor V Leiden) and F2 genes (prothrombin G20210A mutation) were 11.67% (10.27% heterozygous, 1.4% homozygous) and 6.95% (6.39% heterozygous, 0.56% homozygous), respectively. Concurrently, high carrier frequencies for MTHFR c.677C>T, MTHFR c.1298A>C, and PAI-1 4G/5G variants, that are controversially associated with thrombophilia, were observed: 65.28% (52.5% heterozygous, 12.78% homozygous), 53.61% (45% heterozygous, 8.61% homozygous), and 78.61% (49.44% heterozygous, 29.17% homozygous), respectively. The impact of MTHFR genotypes on plasma homocysteine levels was also determined. Male carriers of TT homozygous genotype and CT heterozygous genotype of MTHFR C677T polymorphism had significantly higher levels of plasma homocysteine unrelated to age, compared to those harboring CC homozygous genotype (P=0.028). In unselected patients a high rate of positive thrombophilia tests was observed and the clinical implications of such results need to be carefully examined.

Pregnancy Complications In G20210A Mutation Carriers Associated With High Prothrombin Activity

Objective to study the association between high activity of Factor II (prothrombin) in blood plasma with G20210A mutation and the development of great obstetrical syndromes. Material and methods A prospective clinical cohort study was conducted on 290 pregnant women (average age 31.7±4.7 years old). The main group was made up of 140 G20210A patients, while the control group comprised 150 women with the wild G20210G type. The aim was to evaluate the activity of Factor II in the venous blood plasma during the stages of pregnancy with regard to trophoblast invasion waves. As per results, association analysis of Factor II activity value and gestational complications was carried out. Results In the control group, the median (Me) of Factor II activity ranged from 108% (preconception period) to 144% (pregnancy) [95% CI 130-150]. In patients with the GA type, the value was significantly higher in related periods, ranging from 149% to 181% [95% CI 142-195], p<0.0001. With Factor II activity ranging from 148.5% to 180.6%, pregnancies in the main group had no complications. Higher levels of Factor II activity were associated with the development of early and/or severe preeclampsia (PE) and fetal growth retardation (FGR). Conclusion The data obtained regarding Factor II activity in blood plasma, juxtaposed with the development of great obstetrical syndromes, allow to assume that manifestation of G20210A in early and/or severe PE and FGR is associated with this coagulation factor's level of activity. Threshold value of the Factor II activity with G20210A mutation, allowing to predict the development of PE, comprised 171.0% at the preconception stage (AUC – 0.86; p<0.0001) and within 7-8 weeks of gestation it was 181.3% (AUC – 0.84; p<0.0001).

Inpatient Inherited Thrombophilia Testing at an Academic Health Center: High Cost, Low Value

Testing for inherited thrombophilias following venous and arterial thrombotic events remains controversial. These conditions are associated with an increased risk of initial and recurrent venous thromboembolism (VTE) and, in some cases, arterial events such as strokes and myocardial infarctions. However, testing for them in unselected patients with thrombotic events is not associated with lower recurrence rates, and other risk factors may be more clinically useful for determining whether and for how long to anticoagulate. Further, these tests are expensive and in the setting of an acute thrombosis, many may result in false positives. As such, the American Society of Hematology and American Society for Clinical Pathology recommended in their Choosing Wisely campaigns to not test for inherited thrombophilias after a provoked VTE or in the acute setting, respectively. The AHA/ASA determined that the utility of thrombophilia screening in stroke patients was unknown in its 2014 guidelines. This single institution, retrospective study reviewed all instances of inpatient inherited thrombophilia testing in 2019 at Thomas Jefferson University Hospitals, including its 3 primary hospitals in Philadelphia, PA. Tests included those to evaluate the following conditions: Factor V Leiden (FVL); prothrombin G20210A mutation; Protein C, S, and antithrombin deficiency; hyperhomocysteinemia; and plasminogen activator inhibitor-1 (PAI-1) elevation. The study included 231 patients, among whom a total of 872 tests were sent. Tests sent for non-thrombotic indications, such as homocysteine for B12 or folate deficiency, or in patients with a known deficiency were excluded. Median age of the patients was 50.8 years (IQR 38-63) and 129 (55.8%) were female. Diagnoses for which testing was sent and predisposing risk factors are summarized in Table 1. Arterial events were most common (54.5%), followed by VTE (26.0%). 14.7% of patients had no documented thrombosis, ischemic event, or pregnancy complication. Arterial events primarily included stroke/TIA (74.6%), and 76.7% of patients had at least one documented risk factor for these conditions. VTE was associated with a major transient risk factor or cancer in 32.8% of patients. Among all inherited thrombophilia tests sent, the most common were for the evaluation of FVL (20.9%), hyperhomocysteinemia (17.0%), Protein S deficiency (16.5%), prothrombin G20210A mutation (15.1%), Protein C deficiency (14.8%), and antithrombin deficiency (14.3%) (Table 2). Overall, 83.3% of tests were normal. Tests that were most frequently abnormal included MTHFR mutation (76.0%), antithrombin (36.0%), Protein C antigen (40.0%), PAI-1 (33.3%), and total Protein S (22.2%). Given our lab's references ranges, values for antithrombin, and Protein C antigen and function, and total Protein S that fell below normal but &gt;60% were deemed "borderline positive." The likelihood of an abnormal result was not significantly different in cases of unprovoked VTE or arterial event without a risk factor, compared to those with risk factors. All charts were reviewed, including both inpatient and outpatient notes, to determine short- and long-term clinical decision-making. Importantly, among all positive tests, clinical management was not definitively changed in response to the test result in a single case. In two patients, it was unclear whether anticoagulation was continued based upon the test result. Both patients had heterozygous FVL mutations. Most positive results were deemed by the treating clinicians to be due to the acute thrombotic episode. Last, the hospital's chargemaster was queried, showing that these tests were associated with $398,912 in total charges. This single-institution retrospective study of inpatient inherited thrombophilia tests reveals the limited benefit of thrombophilia testing in the acute setting. Arterial ischemic/thrombotic events were the most common indication for testing, yet over 3/4 of patients had at least one risk factor. Nearly a third of patients with VTE had a major provoking factor, patients in whom thrombophilia testing is not recommended. While nearly 17% of tests returned abnormal, not one was associated with a clear change in clinical management. Despite limited clinical utility, costs of these tests are high. These data justify education and pathway implementation aimed at decreasing inpatient utilization of thrombophilia tests. Disclosures No relevant conflicts of interest to declare.