A case-control study on factor V Leiden: an independent, gender-dependent risk factor for venous thromboembolism

Background Activated protein C resistance (APCR) due to factor V Leiden (FVL) mutation (R506Q) is a major risk factor in patients with venous thromboembolism (VTE). The present study investigated the clinical manifestations and the risk of venous thromboembolism regarding multiple clinical, laboratory, and demographic properties in FVL patients. Material and methods A retrospective cross-sectional analysis was conducted on a total of 288 FVL patients with VTE according to APCR. In addition, 288 VET control samples, without FVL mutation, were also randomly selected. Demographic information, clinical manifestations, family and treatment history were recorded, and specific tests including t-test, chi-square and uni- and multi-variable regression tests applied. Results APCR was found to be 2.3 times significantly more likely in men (OR: 2.1, p < 0.05) than women. The risk of deep vein thrombosis (DVT) and pulmonary embolism (PE) in APCR patients was 4.5 and 3.2 times more than the control group, respectively (p < 0.05). However, APCR could not be an independent risk factor for arterial thrombosis (AT) and pregnancy complications. Moreover, patients were evaluated for thrombophilia panel tests and showed significantly lower protein C and S than the control group and patients without DVT (p < 0.0001). Conclusion FVL mutation and APCR abnormality are noticeable risk factors for VTE. Screening strategies for FVL mutation in patients undergoing surgery, oral contraceptive medication, and pregnancy cannot be recommended, but a phenotypic test for activated protein C resistance should be endorsed in patients with VTE.

Inherited Thrombophilias in Thrombosis Advancement in Microvascular Flap Surgery

Microvascular flap surgery is a reliable method for reconstructive surgery. To avoid and foresee free flap thrombosis advancement after microvascular flap surgery, patient assessment, flawless surgical technique, and eligible perioperative care are pivotal. In this prospective observational study, we aimed to elucidate the most common inherited single nucleotide polymorphisms (SNPs) attributable to free flap thrombosis. A total of 152 patients undergoing microvascular flap surgery during the study period of 2016–2019 were analysed for five SNPs: rs6025 in Factor V Leiden (FVL) gene, rs1799963 in Factor II (FII) gene, rs2066865 in Fibrinogen Gamma Chain gene (FGG), rs2227589 in SERPINC 1 gene and rs1801133 in Methylene Tetrahydrofolate Reductase (MTHFR) gene. Activated protein C resistance (aPCR), prothrombin, antithrombin (AT), fibrinogen and homocysteine plasma levels were measured to determine association with the analysed SNPs and with free flap thrombosis advancement. Our preliminary results show that carriers of FVL mutation were associated with aPCR, as we observed significantly lower aPCR plasma levels in carriers of genotype C/T, as compared to C/C; p = 0.006 (CI 95%, 0.44 to 1.19). Additionally, mean fibrinogen plasma levels were higher in carriers of FGC gene rs2066865 genotype A/A (5.6 ± 1.81 g/l), as compared to G/A and G/G; p = 0.04 (CI 95%, 0.007 to 1.09); p = 0.004 (CI 95%, 0.48 to 2.49), respectively. The study group included 12 patients (7.9%) with free flap thrombosis. For one patient free flap thrombosis advancement might have been related to the rs6025T – FVL mutation with a PCR plasma level 1.21. Lower aPCR levels was associated with carriers of FVL rs6025 C/T and higher fibrinogen plasma levels with carriers of FGG rs2066865 A/A, suggesting that these genotypes might predict higher free flap thrombosis risk, but we found no significant association between analysed SNPs and free flap thrombosis advancement.

Factor V Leiden mutation frequency and geographical distribution in Turkish population

Background and ObjectiveThrombophilia is a term used to define the conditions creating a tendency toward thrombosis. Factor V Leiden (FVL) is the most frequently observed genetic risk factor, and its frequency varies among societies and ethnicities. In this study, our aim is to identify the frequency of FVL mutation in patients with thrombosis, the frequency of FVL mutation for each thrombosis disease, whether there is any difference in the geographical distribution of FVL mutation in the Turkish population, correlation with age and gender, and correlation with arterial and venous thrombosis.MethodsThis is an observational case–control and retrospective study. Cases with the FVL mutation examination with clinical provisional diagnosis of arterial and/or venous thrombosis delivered and with the thrombosis proven by radiological visualization methods and laboratory examinations have been planned to be considered and assessed as cases with thrombosis.ResultsA total of 67 patients with thrombosis and 22 patients without thrombosis have been included within the study. Twenty-six of the cases with thrombosis were from the Black Sea region, 21 were from Eastern Anatolia, 12 were from Central Anatolia, 5 were from Marmara, and 3 were from Southeastern Anatolia. Eleven of the cases without thrombosis were from the Black Sea region, 1 was from Eastern Anatolia, 5 were from Central Anatolia, 2 were from Marmara, 1 was from Southeastern Anatolia, and 2 were from the Aegean region. The significance was resulted from the identification of thrombosis prevalence rate as significantly high in the Eastern Anatolian region.DiscussionFVL mutation frequency is quite common in our country, and there are significant differences particularly in terms of regional distribution. Furthermore, FVL mutation is solely not the risk factor for thrombosis, and other coexisting genetic and acquired risk factors are substantial causes for the development of thrombosis.

DOAC-Remove abolishes the effect of direct oral anticoagulants on activated protein C resistance testing in real-life venous thromboembolism patients

BackgroundDirect oral anticoagulants (DOACs) may cause false results of activated protein C resistance (APC-R) ratio. DOAC-Remove, a new reagent based on activated carbon, has been designed to eliminate the interference of DOACs on coagulation assays. The aim of the study was to investigate whether the use of DOAC-Remove enables to determine APC-R in patients treated with DOACs.MethodsWe assessed 74 venous thromboembolism (VTE) patients, including 25 on rivaroxaban, 25 on apixaban and 24 taking dabigatran. APC-R was determined using the Russell Viper Venom Time (RVVT)-based clotting test. APC-R and DOAC concentrations were tested at baseline and following DOAC-Remove. Thrombophilia, including factor V Leiden (FVL) mutation was tested.ResultsFVL mutation was found in 20 (27%) patients. The APC-R ratio at baseline was measurable in 43 patients (58.1%), including 20 (80%) on rivaroxaban, 19 (76%) on apixaban and four (16.7%) on dabigatran. In patients with measurable APC-R at baseline, the ratio >2.9 was found in 23 patients (53.5%). In 16 (37.2%) subjects APC-R ratio <1.8 suggested FVL mutation which was genetically confirmed. Four (9.3%) FVL carriers on dabigatran showed negative/equivocal APC-R results. In 11 (14.9%) patients taking rivaroxaban or apixaban, in whom blood was collected 2–5 h since the last dose, we observed unmeasurable APC-R. DOAC-Remove almost completely eliminated all plasma DOACs. After addition of DOAC-Remove all APC-R ratios were measurable. In four FVL carriers on dabigatran with false negative APC-R, DOAC-Remove resulted in APC-R ratios <1.8.ConclusionsDOAC-Remove effectively reduces DOACs concentration in plasma, which enables FVL testing using APC-R.

Abstract TP317: Utility and Cost of Inpatient Thrombophilia Testing in Ischemic Stroke Patients Aged 18-60

Introduction: Patients (pts) <60 years with ischemic stroke (IS) are commonly tested for thrombophilias (TP) due to the perception that there could be underlying hypercoagulable states. However, inherited TPs are largely not a risk factor for IS; and testing for acquired TPs in an acute inpatient setting may yield erroneous results that increase health care costs. We reviewed the frequency and cost of TP testing at our institution as part of a plan-do-study act cycle for improving the utilization of inpatient TP testing in young pts after IS. Methods: We performed a retrospective review of 18-60 year old pts admitted for IS to our comprehensive stroke center between 11/2016 and 7/2018. Pts discharged with a stroke etiology not attributed to large vessel (LV), small vessel (SV), or cardioembolic (CE) origin and the initial hospital TP testing monitored. Pts seen subsequently in clinic or later admissions in our system were monitored. Results: Of 1,162 pts, 104 without diagnosed LV/SV/CE etiologies were identified. At least one TP test was performed in 82 (79%) pts (Table 1). In 70 pts testing was done in the initial 24 hrs of hospitalization. One test abnormality was seen in 42 (51%) pts but anticoagulation was initiated in only one 1 patient at discharge. Forty-seven (45%) pts were followed in our outpatient clinic, with a mean follow up of 5 (0.2 – 24) months. TP was confirmed in 3 pts in clinic – two with heterozygous FVL mutation and one with known homozygous FVL mutation. The total charges of the initial inpatient testing is estimated to be as high as $222,150 for 82 patients. Conclusion: Frequent inpatient TP testing in young pts with cryptogenic stroke does not change management and can be costly to the hospital. Based on these results, we created a practice guideline to improve utilization of TP testing starting January 2019. A one year analysis of the effectiveness, safety, and cost for these changes is ongoing.

A Case Report of Idiopathic Catastrophic Thrombotic Syndrome with Purpura Fulminans

Background: Catastrophic thrombotic syndrome (CTS) is a rare life-threatening condition defined as rapid onset of multi-organ thrombosis affecting diverse vascular beds. Predisposing conditions include catastrophic antiphospholipid syndrome (APS), atypical thrombotic thrombocytopenic purpura (TTP), delayed heparin-induced thrombocytopenia and Trousseau syndrome. Patients who do not meet any of these criteria are diagnosed with idiopathic catastrophic thrombotic syndrome. Case description: A 44-year-old Caucasian woman with type II diabetes and hypothyroidism presented with acute onset of myalgia and extensive bruising over a period of four days. Physical exam revealed hypotension, tachycardia, and extensive purpuric and bullous skin lesions. Laboratory evaluation demonstrated microangiopathic hemolysis, thrombocytopenia, elevated D-dimer and coagulopathy suggesting disseminated intravascular coagulation (DIC) along with acute kidney injury (AKI) and transaminitis. Aggressive transfusions including packed red blood cells, fresh frozen plasma, platelets and cryoprecipitate were required to reverse her severe coagulopathy. Ultrasound showed occlusive thrombus in the left basilic vein and the greater saphenous veins bilaterally and heparin infusion was started. IV methylprednisolone, all-trans retinoic acid and doxycycline were empirically given. Workup was negative for any coagulation factor deficiency or hypercoagulable state although heterozygous factor V Leiden (FVL) mutation was found. Bone marrow biopsy was normal. Infectious and auto-immune workups were unremarkable. Skin biopsy showed diffuse intravascular thrombi but no evidence of vasculitis. Two weeks later, she developed Enterobacter bacteremia from infection of her bullous lesions. She was started on broad spectrum antibiotics and transferred to a burn unit. Eventually, her coagulopathy, bacteremia, AKI and transaminitis resolved, she was discharged with indefinite anticoagulation. Discussion: CTS presented in our patient with rapidly progressive thrombosis with consumptive coagulopathy. No obvious instigating source was found, her clinical presentation was out of proportion for the isolated heterozygous FVL mutation. Anticoagulation remained the main therapy in the acute setting and aggressive supportive care in multi-disciplinary setting to manage acute and late complications was required. Conclusion: Through this report, we emphasize the need for early recognition of CTS with this constellation of clinical findings and advocate for urgent interventions to prevent untoward outcomes.

Effects of factor v Leiden polymorphism on the pathogenesis and outcomes of preeclampsia

Background Factor V Leiden polymorphism is a well-recognized genetic factor in the etiology of preeclampsia. Considering that Ghana is recording high incidence of preeclampsia, we examined if factor V Leiden is a contributory factor to its development and pregnancy outcomes. Methods STROBE consensus checklist was adopted to recruit eighty-one (81) consenting subjects after ethical clearance. Subjects were followed up till delivery to obtain outcomes of PE. Routine blood chemistry and proteinuria were done on all samples. Factor V Leiden was characterized by polymerase chain reaction and restriction fragment length polymorphism (RFLP). The data was captured as protected health information (PHI) and analyzed with SPSS version 22. Results Overall allelic frequencies found in FVL exon 10 were 0.67 and 0.33 for G and A alleles respectively. The FVL mutation was more in PE and hypertensive patients. Increased white blood cells, increased uric acid and a three – fold increment of AST / ALT ratio was observed in PE cases when stratified by FVL exons (exon 8 and 10). Significant differences were also observed between FVL and age, systolic blood pressure (SBP), diastolic blood pressure (DBP), liver enzymes, white blood cells (wbc), hemoglobin levels. Conclusion FVL mutation allele frequency was 0.33, a first report. The mutation was associated with increased uric acid, liver enzymes and blood cell indices suggestive of acute inflammation.

Assessment and Reduction of Unnecessary Thrombophilia Testing in Patients 18-60 Years with Acute Cryptogenic Ischemic Stroke

Patients < 60 years with acute ischemic stroke (AIS) are commonly tested for thrombophilia. Underlying this practice is the perception that the stroke may be the result of a hypercoagulable state, especially when an alternative cause is not evident. Although certain conditions, such as antiphospholipid antibody syndrome (APS), can be associated with AIS and require anticoagulation, inherited thrombophilia, largely, is not a risk factor for AIS even in young adults with cryptogenic stroke, as supported by case-control and prospective observational studies. Moreover, testing in the acute phase of AIS may give erroneous results (i.e., increase of Factor 8 as an acute phase reactant), and increase health care costs. To assess our institutional performance on this matter, we conducted a retrospective chart review of 104 patients, age 18-60 years, who were admitted for AIS to Memorial Hermann Hospitals at the Texas Medical Center between 11/2016 and 7/2018, and whose stroke was considered cryptogenic or of undetermined origin (i.e., more than one possible causes) after initial diagnostic evaluation. Mean age at the time of event was 43 (range 20-58) years. There were 61 (59%) males. Fifty nine (57%) patients were White, 42 (40%) Black, 18 (17%) Hispanic, 2 (2%) Asian, and one (1%) of unknown race. Risk factors for AIS were: hypertension in 64 (61%) patients, diabetes in 26 (25%), smoking in 27 (26%), dyslipidemia in 32 (31%), prior AIS in 17 (16%), coronary artery disease in 4 (4%), and obesity in 10 (10%). None had known atrial fibrillation or other cardiac arrhythmia. Thrombophilia testing (at least one test) was performed in 82 (79%) of the patients. In the vast majority (70 patients, 85%) of cases, such testing was done within 1-3 days of admission as part of the initial stroke evaluation. A total of 752 tests were performed on the 82 patients, 56 (7%) of which were positive. Increased Factor 8 (F8) activity (i.e., ≥200%) was the commonest abnormality observed (31/58 patients tested, or 53%), followed by low protein S (PS) activity (13/77, 17%), Factor V Leiden (FVL) mutation (3/71, 4%), low antithrombin (AT) activity (3/73, 4%), elevated homocysteine (2/79, 3%), low protein C (PC) activity (1/76, 1%), and positive APL (1/251, 1%), while no prothrombin gene mutation was seen. All but one of F8, PS, and AT tests were performed in the acute phase of the stroke. The estimated annual cost for testing was $65000. Forty-two (51%) of the 82 patients tested had at least one abnormal test. In 2/42 (5%) of these patients, repeat testing (i.e., PS activity, F8) was done at least a month later, which, however, did not confirm the abnormality. Forty-seven (45%) patients were seen in the Outpatient Neurology Clinic after their stroke, for a median follow up of 5 (0.2 - 24) months. In 54 (52%) patients the cause of stroke remained undetermined even after thorough evaluation. Sixteen (15%) patients had a patent foramen ovale (PFO). Of all patients tested, thrombophilia was confirmed in three, i.e., two patients with heterozygous FVL mutation and one with known homozygous FVL mutation and a significant personal history of venous thromboses. Only in one patient (1/82, 1%) management was changed taking into account the thrombophilia testing results: a 57 year old male with low PS activity (tested 3 months after the stroke) and a PFO not amenable to closure, for whom anticoagulation was started despite the lack of venous thromboembolism. Based on these results, and due to concerns of indiscriminate testing, we created a practice guideline supported by current literature, as a reference for clinicians (see Figure). Briefly, we eliminated inherited thrombophilia testing in the acute phase, and rendered it optional in the chronic phase at the discretion of the treating physician, when anticoagulation is considered (i.e., some cases of PFO or recurrent stroke). Accordingly, we removed these tests from the admission order panel in the Electronic Medical Record. After internal audit and feedback from health care providers across disciplines, we submitted the new guideline for multidisciplinary review and system-wide adoption (i.e., multiple hospitals). We conclude that routine thrombophilia testing is not an effective tool for secondary stroke prevention even in young patients with cryptogenic AIS. Institutional practice guidelines are helpful in tailoring such testing, hence avoiding misdiagnosis of a thrombophilic state and unnecessary costs. Figure Disclosures No relevant conflicts of interest to declare.

Thrombophilia in hepatocellular carcinoma

Background Chronic liver disease and hepatocellular carcinoma (HCC) can cause a disturbance in the coagulation system. In this study, we aimed to assess the risk factors for venous thromboembolism either acquired or hereditary in patients with HCC. Results Serum levels of proteins C and S, AT activity, and lipoprotein (a) were significantly lower in both HCC and cirrhotic patients while homocysteine levels were significantly higher in HCC patients. The prevalence of activated protein C resistance (APCR) and factor V Leiden (FVL) mutation was higher in HCC patients but with no significant differences between the studied groups. With multivariate analysis, prothrombin time, Fbg, protein C and S deficiency, increased lipoprotein (a), hyperhomocysteinemia, APCR, and FVL mutation were independent risk factors for thromboembolic complications in HCC patients. Conclusions Thrombophilic abnormalities are prevalent in HCC patients, and they have a substantial increased risk of venous thromboembolism.

Potential role of Factor V Leiden mutation in adverse pregnancy outcomes: An updated systematic review

Background: Thrombophilia is an inherited or acquired predisposition for development of thrombosis. One of the common thrombophilia polymorphisms is Factor V Leiden (FVL) mutation, which may contribute to negative pregnancy outcomes. This systematic review study seeks to describe the potential effects of factor V Leiden mutation on adverse pregnancy outcomes. Methods: Pubmed, Embase, ISI Web of Sciences, Scopus, ScienceDirect, Proquest and Google Scholar, for articles published during 1996-2017. Articles were evaluated by the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist for standard reporting. As well, the quality of studies was assessed by the Newcastle-Ottawa Scale (NOS). Results: A total of 14 studies were eligible based on the inclusion criteria. The papers were scored by the STROBE checklist. The range of STROBE score was 15-20. Only 37.5% of the studies confirmed the relationship between fetal loss and FVL. The effect of FVL mutation on spontaneous abortions and In Vitro Fertilization (IVF) failures was demonstrated in all the studies. In the reviewed studies, there was no observed relationship between FVL mutation with intrauterine growth restriction (IUGR), preeclampsia, placental abruption or small for gestational age (SGA). Conclusion: The reviewed studies showed an unclear association between FVL mutation and stillbirth, IUGR, preeclampsia, or placental abruption. The exact effects of hereditary thrombophilia on pregnancy outcome is also still controversial. However, FVL mutation appeared to have an effect on spontaneous abortions and IVF failures. Therefore, screening patients for thrombophilic polymorphisms might be helpful.