Diagnosis and treatment of venous thromboembolism during pregnancy relate to genetic polymorphism

OBJECTIVES

Previous research had shown that age, a positive family history, comorbidities, major surgical operations, gestation, and use of several medications could increase the incidence of venous thromboembolism (VTE). With the development of medical and clinical individualized treatment, many people exposed to above risk factors did not develop VTE, suggested that genetic factors are also involved in the development of VTE. In this review, we aim to summarize VTE diagnosis and treatment in pregnancy women related to gene polymorphism.

METHODS

A comprehensive electronic search using PubMed, MEDLINE, EMBASE and Web of Science was conducted to find relevant journal articles with key search terms including: "pregnancy OR pregnant," "venous thromboembolism OR VTE," "deep vein thrombosis OR DVT," "pulmonary embolism OR PE," and "genetic OR gene." Prominent publications from establishment of database till present were analysed to achieve a deeper understanding of VTE during pregnancy relate to genetic polymorphism, and the information was then collated to form this review.

RESULTS

The literature review revealed that inherited thrombophilia significantly associated with the development of VTE, especially the factor V Leiden (FVL) and prothrombin gene mutation (PGM). Furthermore, the role of methylenetetrahydrofolate reductase (MTHFR) gene mutation in the development of pregnancy-related VTE remains controversial, further study is required. In the present study, Marburg I polymorphism (G511 E), c.1538 G>A and c.1601 G>A in Factor V (FV), JAK2V617 F mutation were reported as an independent risk factor for VTE, there is no sufficient evidence to confirm the gene mutation is related to VTE during pregnancy, these factors appearing as another promising potential diagnostic marker of VTE during pregnancy. Besides, the dosages of heparin in the treatment of VTE during pregnancy need be adjusted according to gene polymorphism of these population, particularly FVL or PGM carriers, and this area is not studied deeply, it is worth further study.

CONCLUSION

Inherited thrombophilia significantly associated with the development of VTE, especially the FVL and PGM, however the relation between MTHFR gene mutation and pregnancy-related VTE remains controversial, further study is needed. In addition, the dosages of heparin in the treatment of VTE during pregnancy suggested to adjusted based on gene polymorphism in FVL and PGM, and establish better prediction models is a direction of future research.

Sex-Specific Risk Factors for Deep Venous Thrombosis and Pulmonary Embolism in a Population-Based Historical Cohort Study of Middle-Aged and Older Individuals

Background Whether sex-specific differences exist for risk factors for pulmonary embolism (PE) and deep venous thrombosis (DVT), with the exception of pregnancy and estrogen therapy, has been sparsely studied. We aimed to study whether sex-specific differences of risk factors exist for noncancer-related DVT and PE in middle-aged and older individuals without cardiovascular history or previous diagnosis in a population-based historical (retrospective) cohort. Methods and Results Potential venous thromboembolism (VTE) risk factors were registered at baseline in 15 807 women and 9996 men aged 44 to 74 years, who participated in the Malmö Diet and Cancer study (1991-1996). We excluded subjects with a previous history of VTE, cancer, a diagnosis of cardiovascular disease, or a diagnosis of cancer-associated VTE during follow-up. Patients were followed up from baseline until the first event of PE or DVT, death, or December 31, 2018. During the follow-up period, 365 (2.3%) women and 168 (1.7%) men were affected by first DVT, and 309 (2.0%) women and 154 (1.5%) men were affected by first PE. In the multivariable Cox regression models, the anthropometric obesity markers of weight, body mass index, waist and hip circumference, fat percentage, and muscle weight were in a dose-dependent way associated with DVT and PE among women but not men. In an analysis that included patients with cardiovascular disease and cancer-related VTE, the results were similar for women. For men, several obesity measures became significantly associated with PE or DVT but were weaker than in women, especially for DVT. Conclusions Anthropometric obesity measures are more important risk factors for both DVT and PE among women than men, especially for individuals without cardiovascular history or previous diagnosis or cancer-related VTE.

Thrombotic risk determined by protein C receptor (PROCR) variants among middle-aged and older adults: a population-based cohort study

BACKGROUND

The protein C (PC) anticoagulant system has a key role in maintaining hemostatic balance. One missense (Ser219Gly) variant in the protein C receptor (PROCR) was associated with venous thromboembolism (VTE) in genome-wide association studies.

OBJECTIVES

This study aimed to determine the thrombotic risk of rare and common PROCR variants in a large population-based cohort of middle-aged and older adults.

PATIENTS/METHODS

The exonic sequence of PROCR was analyzed for the Ser219Gly variant and other qualifying variants in 28,794 subjects (born 1923-1950, 60% women) without previous VTE, who participated in the Malmö Diet and Cancer study (1991-1996). Incidence of VTE was followed up until 2018. Qualifying variants were defined as loss-of-function or non-benign (PolyPhen-2) missense variants with minor allele frequencies (MAF) < 0.1%.

RESULTS

Resequencing identified 36 PROCR variants in the study population (26,210 non-VTE exomes and 2584 VTE exomes), 11 synonymous, 22 missense and three loss-of-function variants. Kaplan-Meier analysis of the known Ser219Gly variant (rs867186) showed that homozygosity for this variant increased the risk of disease whereas heterozygosity showed no effect. Cox multivariate regression analysis revealed an adjusted hazard ratio of 1.5 (95%CI 1.1-2.0). Fifteen rare variants were classified as qualifying and were included in collapsing analysis (burden test and SKAT-O). They did not contribute to risk. However, a Arg113Cys missense variant (rs146420040; MAF=0.004) showed an increased VTE risk (HR=1.3; 95%CI 1.0-1.9).

CONCLUSIONS

Homozygosity for the Ser219Gly variant and a previously identified functional PROCR variant (Arg113Cys) was associated with VTE. Other variants did not contribute to VTE.

The risk of venous thromboembolism attributed to established prothrombotic genotypes

BACKGROUND

The proportion of venous thromboembolism (VTE) events that can be attributed to established prothrombotic genotypes has been scarcely investigated in the general population. We aimed to estimate the proportion of VTEs in the population that could be attributed to established prothrombotic genotypes using a population-based case-cohort.

METHODS

Cases with incident VTE (n=1,493) and a randomly sampled sub-cohort (n=13,069) were derived from the Tromsø Study (1994-2012) and the Nord-Trøndelag Health (HUNT) Study (1995-2008). DNA-samples were genotyped for 17 single nucleotide polymorphism (SNPs) associated with VTE. Hazard ratios with 95% confidence intervals (CIs) were estimated in Cox regression models. Population attributable fraction (PAF) with 95% bias-corrected CIs (based on 10,000 bootstrap samples) were estimated using a cumulative model where SNPs significantly associated with VTE were added one-by-one in ranked order of the individual PAFs.

RESULTS

Six SNPs were significantly associated with VTE (rs1799963 [Prothrombin], rs2066865 [FGG], rs6025 [FV Leiden], rs2289252 [F11], rs2036914 [F11] and rs8176719 [ABO]. The cumulative PAF for the six-SNP model was 45.3% (95% CI 19.7-71.6) for total VTE and 61.7% (95% CI 19.6-89.3) for unprovoked VTE. The PAF for prothrombotic genotypes was higher for DVT (52.9%) than for PE (33.8%), and higher for those aged <70 years (66.1%) than for those aged ≥70 years (24.9%).

CONCLUSIONS

Our findings suggest that 45-62% of all VTE events in the population can be attributed to known prothrombotic genotypes. The PAF of established prothrombotic genotypes was higher in DVT than in PE, and higher in the young than in the elderly.

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.

Rare variants in MTHFR predispose to occurrence and recurrence of pulmonary embolism

BACKGROUND

Rare genetic variants play a critical role in unprovoked pulmonary embolism (PE). However, the known risk genes only account a small proportion of patients with PE. The objective of this study was to investigate the relationship between the rare variants of gene encoding methylenetetrahydrofolate reductase (MTHFR) and the initiation and long-term clinical outcomes of PE.

METHODS

The rare variants of MTHFR were detected by whole exome sequencing of DNA from 258 unprovoked PE cases and 11,451 controls. Correlation of genotype and clinical phenotype and outcome were evaluated at baseline and after follow-up.

RESULTS

MTHFR rare variants were found in 15 of 258 cases (5.81%) and 241 of 11,451 controls (2.10%), conferring 2.87-fold greater odds of the PE occurrence (OR = 2.87, 95% CI = 1.68-4.91, P = 5.6 × 10^-5, chi-square test). The patients with MTHFR rare variants had higher plasma level of homocysteine than those without. During a follow-up of 3.0 years, a total of 84 events were identified. The recurrent PE (two or more events of PE) were significantly higher in patients carrying MTHFR rare variants (8/15, 53.3%) compared with those without (55/239, 23.0%) (P = 0.023).

CONCLUSION

We speculate that MTHFR rare variants may increase the occurrence and recurrence of PE.

Carvalho M, Morishita E. Racial differences in protein S Tokushima and two protein C variants as genetic risk factors for venous thromboembolism

BACKGROUND

Racial differences in genetic risk factors for venous thromboembolism (VTE) are elucidated, with factor V Leiden and prothrombin G20210A being prevalent among the Caucasian population but rare among non-Caucasians.

OBJECTIVES

To assess the worldwide distribution of three gene polymorphisms previously identified as genetic risk factors among East Asian subpopulations: protein S (PS) Tokushima (p.Lys196Glu), protein C (PC) p.Arg189Trp, and PC p.Lys193del.

METHODS

An international collaborative study group of seven centers in five countries-Japan, South Korea, Singapore, Hungary, and Brazil-was created, and genotype analyses were performed. A total of 2850 unrelated individuals (1061 patients with VTE and 1789 controls) were included.

RESULTS

PS Tokushima was confined to Japanese patients with VTE (allele frequency, 2.35%) and controls (1.12%), with an odds ratio (OR) of 2.15 (95% confidence interval, 1.16-3.99). PC p.Arg189Trp carriers were prevalent among Chinese and Malay patients with VTE in Singapore, with allele frequencies of 10.53% and 22.73%, respectively. Carriers of PC p.Lys193del were identified among Japanese and Korean patients with VTE (0.87% and 2.35%, respectively) and controls (0.36% and 1.07%, respectively), with the OR for VTE not being significant, and Chinese patients with VTE in Singapore (5.26%). In contrast, no carriers of PS Tokushima and two PC gene variants were found among patients with VTE or controls from Hungary, Brazil, or Indians in Singapore.

CONCLUSION

The three variants were prevalent among East and Southeast Asians, having some differences in geographic distribution, but were absent among Caucasian subpopulations and Brazilians.

Comparison between thrombophilic gene polymorphisms among high risk patients

Introduction. The purpose of this study was to compare the role of the thrombophilic variants among two groups of high risk patients with vascular disorders and recurrent pregnancy loss.

Methods. 200 patients, including 76 with thrombotic accidents and 124 with two or more idiopathic recurrent miscarriage during the first trimester, were tested for the presence of Factor V (F V) Leiden G1691A, Factor II (F II) G20210A, plasminogen activator inhibitor (PAI) 4G/5G, and methylenetetrahydrofolate reductase (MTHFR) C677T polymorphisms using Real time polymerase chain reaction (RT – PCR) in the Laboratory of Medical Genetics, Varna, Bulgaria between June 2016 and May 2019. Frequencies of thrombophilic gene polymorphisms were compared among the two populations and to the expected genotype frequencies.

Results. Individuals with a history of vascular disorders had a significantly higher frequency of F V Leiden variant compared to women with recurrent miscariage. There was no statistical difference between the analyzed patients for the other three thrombophilic polymorphisms. The allelic frequencies and the expected genotype frequencies of the F V, F II and MTHFR polymorphisms were calculated according to Hardy-Weinberg equilibrium. The percentages of the homozygotes for F V and F II were higher than expected in the two groups of patients. For the MTHFR there was no difference.

Conclusion. F V Leiden remains the strongest risk factor for vascular disorders and recurrent pregnancy loss. Screening for this variant should be recommended to patients with thrombotic accidents and women with repeated miscarriage. The role of F II, PAI and MTHFR remains controversial.

A multicenter study of thromboembolic events among patients diagnosed with ROS1-rearranged non-small cell lung cancer

OBJECTIVES

This study aimed to describe the longitudinal thromboembolism (TE) risk relative to the natural history of disease and clinical course of ROS1 rearranged non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

Cases of ROS1-rearranged NSCLC from six Australian hospitals were pooled and evaluated for incidence, timing, predictors and outcomes of venous or arterial TE, as well as objective response rate (ORR) to active therapy and overall survival (OS).

RESULTS

Of 42 patients recruited, 20 (48%) experienced TE; one (2%) arterial, 13 (31%) a pulmonary emboli (PE), and 12 (29%) a deep vein thrombosis. Among those with TE, six (30%) experienced multiple events, three as concurrent and three as recurrent diagnoses. The cumulative incidence of TE over time, adjusted for death as a competing risk factor, approached 50%. TE occurred prior to, during and post the peri-diagnostic period and occurred irrespective of treatment strategy. A thrombophilia was identified in n = 3/10 (30%) cases screened: in two factor V Leiden and in one anti-thrombin III (ATIII) deficiency. Median OS was 21.3 months in those with TE vs. 28.8 months in those without; hazard ratio 1.16 (95%CI 0.43-3.15). Respective ORR to first-line therapy with TE was 50% vs. 44% without TE in the chemotherapy arm and 67% vs. 50% in the targeted therapy arm.

CONCLUSION

In the rare cancer subtype, ROS1, these real-world data demonstrate sustained TE risk beyond the diagnostic period irrespective of therapeutic strategy. High incidence of PE, concurrent TE, and recurrent TE warrant validation in larger cohorts. Consideration of primary thromboprophylaxis in ROS1 populations is recommended.

Pulmonary embolism location is associated with the co-existence of the deep venous thrombosis

: Multiple studies have shown that in approximately half of individuals with pulmonary embolism (PE), the deep venous thrombosis (DVT) is not evident at the moment of PE diagnosis. The underlying factors and the origin of PE in these patients are not completely understood: missed DVT, embolization of DVT in its entirety, or de-novo PE being possible explanations. The aim of this study was to evaluate the differences in PE patient with or without co-existing DVT. Sixty-three consecutive PE patients were included. Whole leg bilateral Doppler compression ultrasound was performed to all patients. The PE location and extension, C-reactive protein, platelet count, hemostatic markers FV, FVIII, FXIIIa, Fibrinogen, von Willebrand factor antigen, thrombomodulin were assessed. Thorough clinical assessment including echocardiography and pulmonary function tests were performed upon arrival and seven months later. The mean age of the patients was 57 years (SD 17.3) and 33 (52%) were women. Thirty-one patients (49.2%) had co-existing DVT. The presence of DVT was associated with the proximal location of the PE (100%), whereas none of the patients (n = 10) with exclusively peripheral PE had co-existing DVT. The PE extension, the measured hemostatic and inflammatory markers or the patient characteristics did not statistically differ between patients with isolated PE and PE with co-existing DVT. In roughly half of the PE patients no DVT could be detected. The location of the PE was associated with the presence of co-existing DVT. There were no differences in the PE extension, hemostatic markers or in the patient characteristic between patients with isolated PE or PE with co-existing DVT.

Assessment of genetic and non-genetic risk factors for venous thromboembolism in glioblastoma - The predictive significance of B blood group

INTRODUCTION

Venous thromboembolism (VTE) is a common problem among patients with glioblastoma multiforme (GBM) and with some other cancers. Here, we evaluated genetic and non-genetic potential risk factors for VTE among GBM patients.

MATERIALS AND METHODS

A cohort of 139 patients treated with concomitant radiotherapy and temozolomide were included in the study. Next generation sequencing and genotyping approaches were applied to assess genetic risk factors in the haemostatic system. Clinical data including surgery, reoperation as well as blood group and patient information such as age and gender were available from patient records. Logistic regression analysis was performed to asses VTE risk.

RESULTS

In the study 47 patients (34%) were diagnosed for VTE during the course of their disease. When genetic and non-genetic potential risk factors were evaluated, only B blood group was found to be significantly associated with VTE incidence (odds ratio [OR] = 6.91; confidence interval [CI] = 2.19-24.14; P = 0.001). In contrast, A and O blood groups did not correlate with VTE risk. Frontal lobe tumor location also seemed to slightly increase VTE risk compared to other brain sites (OR = 3.14; CI = 1.1-10.7) although the significance level was at borderline (P = 0.05). Current study identified B blood group as the component in non-O blood groups that is responsible for increased VTE risk.

CONCLUSION

In conclusion, these results suggest for the first time that B blood group is predictive for VTE incidence among patients with glioblastoma, information that may be potentially valuable when selecting GBM patients who are at risk for VTE for anticoagulant prophylaxis.

Postoperative Joint Replacement Complications in Swedish Patients With a Family History of Venous Thromboembolism

IMPORTANCE

The associations of a family history of venous thromboembolism (FH-VTE) with postoperative venous thromboembolism (VTE) and major bleeding after joint replacement surgical procedures are unknown.

OBJECTIVE

To determine the risk of VTE and major bleeding in patients after primary hip or knee replacement surgical procedures.

DESIGN, SETTING, AND PARTICIPANTS

Cohort study using nationwide population-based databases of Swedish patients without a history of VTE who underwent joint replacement surgical procedures. Patients who had primary hip or knee replacement surgical procedures between July 1, 2005, and August 31, 2012, were identified. Patients born after 1931 without previous VTE were identified in the Swedish Multi-Generation Register. Only individuals with at least 1 parent and 1 full sibling alive between 1964 and the date for the surgical procedure were included. The data analysis was performed from September 1, 2017, to June 15, 2018.

EXPOSURES

Family history of VTE in a parent and/or a full sibling before the date of the surgical procedure.

MAIN OUTCOMES AND MEASURES

Venous thromboembolism and major bleeding within 90 days of the surgical procedure.

RESULTS

Of 69 505 study participants, 37 989 (54.7%) were women, and the median (interquartile range) age at the date of discharge was 65 (59-70) years. A total of 803 of 69 505 (1.2%) patients experienced postoperative VTE and 1285 (1.8%) experienced major bleeding. The cumulative VTE risk for those with FH-VTE was 231 of 15 858 (1.5%) and for those without an FH-VTE was 572 of 53 647 (1.1%) (P < .001). The cumulative bleeding risk for those with FH-VTE was 261 of 15 858 (1.6%) and for those without an FH-VTE was 1024 of 53 647 (1.9%) (P = .03). There was an association of patients with an FH-VTE who had increased VTE risk (adjusted hazard ratio [HR], 1.36; 95% CI, 1.17-1.59) and reduced bleeding risk (adjusted HR, 0.84; 95% CI, 0.74-0.97). There was an interaction between time after discharge and FH-VTE regarding VTE and major bleeding. An FH-VTE was not associated with VTE after discharge during the first week (HR, 1.13; 95% CI, 0.86-1.49). After 7 days from discharge, FH-VTE was associated with VTE (HR, 1.49; 95% CI, 1.24-1.79). An FH-VTE reduced major bleeding risk during the first 7 days after discharge (HR, 0.78; 95% CI, 0.66-0.91) but not thereafter (HR, 1.10; 95% CI, 0.84-1.44). Postoperative VTE heritability (SE) was 20% (6%).

CONCLUSIONS AND RELEVANCE

Familial and most likely genetic factors appear to affect VTE and major bleeding risk following hip and knee replacement surgical procedures. Prolonged VTE prophylaxis might be beneficial in predisposed individuals. There may be a possible evolutionary advantage of prothrombotic genes protecting against traumatic bleeding.