Factor V Leiden: a clinical review

Elevated FVIII levels in hereditary hemorrhagic telangiectasia: Implications for clinical management

Objectives

The objective of this study was twofold: to determine the prevalence of arterial and venous thromboembolic events in the Norwegian Hereditary Hemorrhagic Telangiectasia (HHT) population, and to explore potential factors linked to such events, with particular emphasis on FVIII.

Methods

Patients with an HHT diagnosis attending the Otorhinolaryngology Department at Oslo University Hospital-Rikshospitalet were included consecutively between April 2021 and November 2022. We recorded the participants' medical history with an emphasis on thromboembolic events. Measurements of blood constituents, including FVIII, FIX, vWF, hemoglobin, iron, ferritin, and CRP were performed.

Results

One hundred and thirty-four patients were included in the study. The total prevalence of thromboembolic events among the participants was 23.1%. FVIII levels were high (>150 IU/dL) in the majority of HHT patients (n = 84) (68.3%) and were significantly associated with thromboembolic events (p < .001), as was age. Of the patients with high FVIII levels, 28 (33%) had experienced a thromboembolic event. Furthermore, FVIII levels were measured consecutively in 51 patients and were found to fluctuate above or below 150 IU/dL in 25% of these cases.

Conclusion

Thromboembolic events are highly prevalent in the Norwegian HHT population and are significantly associated with FVIII levels. FVIII levels can fluctuate, and measurements should be repeated in HHT patients to assess the risk of thromboembolic events.

Level of Evidence

4.

Aldehyde Accumulation in Aged Alcoholic Beer: Addressing Acetaldehyde Impacts on Upper Aerodigestive Tract Cancer Risks

Aldehydes, particularly acetaldehyde, are carcinogenic molecules and their concentrations in foodstuffs should be controlled to avoid upper aerodigestive tract (UADT) and liver cancers. Highly reactive, acetaldehyde forms DNA and protein adducts, impairing physiological functions and leading to the development of pathological conditions. The consumption of aged beer, outside of the ethanol metabolism, exposes habitual drinkers to this carcinogen, whose concentrations can be over-increased due to post-brewing chemical and biochemical reactions. Storage-related changes are a challenge faced by the brewing industry, impacting volatile compound formation and triggering flavor instability. Aldehydes are among the volatile compounds formed during beer aging, recognized as off-flavor compounds. To track and understand aldehyde formation through multiple pathways during beer storage, consequent changes in flavor but particularly quality losses and harmful compound formation, this systematic review reunited data on volatile compound profiles through gas chromatography analyses from 2011 to 2021. Conditions to avoid flavor instability and successful methods for reducing beer staling, and consequent acetaldehyde accumulation, were raised by exploring the dynamic conversion between free and bound-state aldehydes. Future research should focus on implementing sensory analyses to investigate whether adding aldehyde-binding agents, e.g., cysteine and bisulfite, would contribute to consumer acceptance, restore beer flavor, and minimize acetaldehyde-related health damage.

Safety of DIEP Flap Reconstruction in Patients with Factor V Leiden: A Retrospective Cohort Study

Background:

Factor V Leiden (FVL) is the most common inherited thrombophilia in White people. Thrombotic complications resulting from free flap breast reconstruction in FVL patients have been studied to a limited degree. We evaluated whether patients heterozygous for a FVL mutation undergoing deep inferior epigastric perforator flap reconstruction had increased risk of micro- or macrovascular thrombotic complications compared with patients without a diagnosed thrombophilia.

Methods:

We performed a retrospective cohort study of deep inferior epigastric perforator flap reconstructions at Brigham and Women’s Hospital (1/2015–12/2020) comparing patients diagnosed as FVL heterozygotes compared with matched controls without a diagnosed thrombophilia. Patients were matched using coarsened exact matching algorithm based on clinical characteristics. The primary outcomes were micro- (return to OR for flap compromise, flap loss) and macrovascular (venous thromboembolism) complications.

Results:

A total of 506 patients (812 flaps) were included in this study. Eleven patients (17 flaps) were FVL heterozygotes. After matching, 10 patients (16 flaps) with FVL were matched to 55 patients (94 flaps). The return to OR for flap compromise was 0% in the FVL cohort compared with 5% (n = 5/94, 3/94 flaps lost, P = 1.00) in the matched controls (1.9%, n = 15/795 in unmatched controls, 0.6%, n = 5/795 loss rate). There were zero venous thromboembolism events among FVL patients compared with 2% of controls (n = 1/55).

Conclusions:

FVL heterozygosity did not increase the risk of micro- or macrovascular complications in patients undergoing deep inferior epigastric perforator flap breast reconstruction. This study supports the safety of microvascular reconstruction in this group of patients when appropriate venous thromboembolism prophylaxis is given.

Increase in the risk of ST elevation myocardial infarction is associated with homocysteine level

BACKGROUND AND AIMS

The present study aimed to investigate the relationship between coagulation defects and ST elevation myocardial infarction (STEMI) in patients without any known coronary artery risk factors and considered low risk according to the Framingham risk classification.

METHODS

This study included 76 (73.6% male) STEMI patients without any known risk factors for coronary artery disease and 56 healthy controls (67.8% male) with similar characteristics.

RESULTS

Factor V Leiden mutation was noted in two patients and in one control. There were no significant differences in protein C, protein S, or antithrombin 3 values between the patient and control groups (p = 0.405, p = 0.476, and p = 0.221, respectively). None of the participants had antiphospholipid syndrome, factor V deficiency, or factor VII deficiency. Plasma homocysteine level was significantly higher in the patient group (19.0 ± 3.6) μmol/L than in the control group (15.8 ± 4.2) μmol/L (p = 0.008). Homocysteine levels in both groups were higher in males without a statistically significant difference. Vitamin B12 and folate levels, which are directly related to homocysteine metabolism, did not differ significantly between groups. Correlation analysis showed that the homocysteine level was not correlated with lipid parameters, folate, or vitamin B12.

CONCLUSION

Homocysteine level was significantly higher in acute MI in patients without any risk factors and were considered low risk according to the Framingham risk score. The findings support the hypothesis that homocysteine level may be an independent risk factor for coronary artery disease.

Integrating genotypic data with transcriptomic and proteomic data

Historically genotypic variation has been detected at the phenotypic level, at the metabolic level, and at the protein chemistry level. Advances in technology have allowed its direct visualisation at the level of DNA variation. Nevertheless, there is still an enormous interest in phenotypic, metabolic and protein property variability, since such variation gives insights into potential functionally important differences conferred by genetic variation. High-throughput transcriptomics and proteomics applied to different individuals drawn from a population has the potential to identify the functional consequences of genetic variability, in terms of either differences in expression of mRNA or in terms of differences in the quantities, pI(s) or molecular weight(s) of an expressed protein. Family studies can define the genetic component of such variation (segregation analysis) and with the genotyping of well-spaced markers can map the causative factors to broad chromosomal regions (linkage analysis). Association studies in the variant proteins have the greatest power to confirm the presence of cis-acting genetic variants. The most powerful study designs may combine elements of both family and association studies applied to proteomic and transcriptomic analyses. Such studies may provide appreciable advances in our understanding of the genetic aetiology of complex disorders.

Usefulness of factor V Leiden mutation testing in clinical practice

We have investigated the clinical usefulness of the activated protein C resistance (APCR)/factor V Leiden mutation (FVL) test by sending out questionnaires to all Norwegian physicians who ordered these tests from our publicly funded service laboratory during a 3-month period, and of whom 70% (267/383) responded. Indications for testing, patient follow-up, the use of APCR versus FVL tests and differences in practice between hospital doctors and GPs were examined. We found that 46% of the tests were predictive, ordered for risk assessment in healthy individuals with no previous history of venous thromboembolism (VTE). Among these, 42% of the tests were taken on the initiative of the patient and 24% were screening tests before prescription of oral contraceptives. In total, 54% of the tests were classified as diagnostic, among which 42% were ordered owing to a previous history of VTE and 22% to a history of brain stroke or myocardial infarction. The prevalence of FVL heterozygotes was not significantly different between the predictive and diagnostic test groups, that is, 26 and 20%, respectively. Only the predictive tests influenced patient follow-up. Here, the physician's advice to patients depended on the test result. In general, the clinical usefulness of APCR/FVL testing was low. Many tests were performed on unsubstantiated or vague indications. Furthermore, normal test results led to unwarranted refrain from giving advice about antithrombotic measures, leading to potential harm to the patient.

Comparison of the Prevalence of APC-resistance in Vascular Patients and in a Normal Population Cohort in Western Germany

OBJECTIVE

To compare the prevalence of APC-resistance (APC-R) in patients with peripheral vascular disease and the general population.

DESIGN

Prospective cohort examination.

MATERIALS AND METHODS

Three hundred and eleven patients (group A) suffering from arterial occlusive disease or an abdominal aortic aneurysm were prospectively screened for APC-R. There were 228 men and 83 women with a mean age of 65 years (20-88 years). Two hundred and sixty patients underwent an open surgical or interventional procedure. A total of 306 patients were followed clinically for an average of 8 months (1-31 months). Two hundred and seven healthy volunteers (group B) served as a control group.

RESULTS

The prevalence of a functional APC-R was 11% (33/311) and 8% in groups A and B, respectively, (p = 0.272). APC-R did not occur more frequently among patients who were treated primarily for a bypass occlusion (3/21 vs 30/290) (p = 0.476). None of five patients who had a postinterventional graft or vessel occlusion (1.9%) had an APC-R. Sixteen patients (5%) experienced an arterial occlusion during follow-up of which two had APC-R.

CONCLUSIONS

Previously published increased prevalence rates of APC-R in patients with arterial disorders could not be confirmed in this study. A firm association between the presence of APC-R and previous bypass occlusion or postoperative failure of the vascular reconstruction could not be demonstrated.

Factor V Leiden and risk of ischemic stroke in nonvalvular atrial fibrillation: the AnTicoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study

BACKGROUND

Atrial fibrillation is a major cause of cardioembolic stroke. Since atrial and venous pressures are similar, genetic variants that promote venous thromboembolism may increase the risk of atrial thrombi and subsequent stroke in atrial fibrillation.

METHODS

We conducted a nested case-control study of the association between the presence of factor V Leiden polymorphism and incident ischemic stroke within a prospective cohort of 13,559 adult patients with diagnosed nonvalvular atrial fibrillation between July 1, 1996 and December 31, 1997. Incident cases with ischemic strokes were identified through August 31, 1999 and matching stroke-free controls were enrolled.

RESULTS

One hundred thirty-seven case patients with incident stroke and 214 controls were enrolled. Cases were older, more likely to be women, and more likely to have a prior stroke, heart failure, hypertension, diabetes, and coronary disease. The factor V Leiden polymorphism was present in 5.8% of cases and 3.7% of controls (P = 0.36). Among non-anticoagulated patients, 7/96 (7.3%) case patients and 3/81 (3.6%) control subjects were heterozygous for factor V Leiden (Odds Ratio 2.1 [95% CI: 0.5-8.4]). Adjustment for known stroke risk factors did not significantly change the observed association in non-anticoagulated patients (adjusted OR 1.9 [0.5-8.0]).

CONCLUSIONS

Within a large nested case-control sample of patients with atrial fibrillation, factor V Leiden was not significantly associated with risk of stroke. However, given the suggestive nature of our findings, further study in even larger numbers of patients is needed to clarify the impact of factor V Leiden on stroke risk in atrial fibrillation.

Association between factor V Leiden mutation and the hemiconvulsion, hemiplegia, and epilepsy syndrome: report of two cases

The factor V Leiden mutation is the most common hereditary cause of venous thrombosis in our population. In the pediatric population, it has been associated with cerebrovascular thrombosis, cerebral palsy, and prosencephaly in neonates. We present two children with hemiconvulsion, hemiplegia, and epilepsy syndrome in whom the cause is likely attributable to the factor V Leiden mutation. We suggest that patients presenting with hemiconvulsion, hemiplegia, and epilepsy syndrome should be routinely investigated for factor V Leiden, and, if positive, careful consideration should be given to therapeutic and prophylactic anticoagulation as this may improve long-term outcome.

Thrombophilia and chronic venous ulceration

It is known that thrombophilia (TP) is a risk factor for deep venous thrombosis (DVT), and that DVT predisposes to chronic venous ulceration (CVU). However, the relationship between TP and CVU has not been well studied. Review of the literature reveals that the prevalence of TP in CVU patients is high--similar to the prevalence found in patients with a history of DVT. This is despite many patients with CVU having no clear history, or duplex evidence of previous DVT. TP may predispose to CVU by leading to macro- or micro-vascular thrombosis. This association raises several issues regarding the investigation, prevention and management of patients with venous disease.