The role of natural anticoagulant deficiencies and factor V Leiden in the development of idiopathic portal vein thrombosis

One of the causes of portal hypertension is portal vein thrombosis (PVT). The aim of this study was to determine whether natural anticoagulant deficiencies, activated protein C resistance (APCR), and factor V Leiden play a role in the development of PVT, leading to cavernous transformation of the portal vein (CTPV). Twenty-three patients with idiopathic CTPV (group 1) seen at Hacettepe University Hospital during the past 12 years were identified and prospectively studied. These 23 patients underwent a detailed hematological evaluation including measurement of protein S, protein C, antithrombin III, activated protein C resistance (APCR), and factor V Leiden gene mutation. Additionally, all patients were tested for anticardiolipin antibodies (ACA), IgG, IgM, and lupus anticoagulant (LA). Natural anticoagulants and APCR were measured using available commercial kits, and factor V Leiden mutation (R506Q) was detected by Mnl I digestion of an amplified factor V DNA fragment. All parameters were measured at least 6 months after the diagnosis of CTPV was established. No patient was on anticoagulant or antiaggregant treatment while tested. The findings in these 23 patients were compared with those in 20 healthy control subjects (group 2), in whom all tests mentioned above were also performed. In 23 patients (group 1), who had no recognizable factor for portal vein thrombosis, considerably natural anticoagulant deficiencies and factor V Leiden mutation positivity were found when we compare them to those healthy controls (group 2). The protein C levels of six patients (26%), the protein S levels of 10 patients (43.5%), and the antithrombin III levels of five patients (26%) were lower than in control subjects. Two patients were found to have combined protein S and antithrombin III deficiency, and one had combined protein S and C deficiency and APCR. APCR was detected in seven of the 23 patients, and six of these seven patients were found to have R506Q factor V Leiden mutations. In group 1, ACA IgG levels were higher in four patients (17%) and ACA IgM level was higher in one (4%) compared with the control group. LA was positive in only one patient in group 1. Natural anticoagulant deficiencies and factor V Leiden mutation are strongly associated with PVT. The natural anticoagulant deficiencies and APCR (almost totally caused by R506Q mutation) produce a favorable medium for thrombus generation. PVT seems to be related to the natural anticoagulant deficiencies and factor V Leiden R506Q mutation. A combination of these defects increases the incidence of PVT and these factors should be evaluated carefully in patients with idiopathic CTPV.

[Oral contraceptives and activated protein C resistance: a paradigmatic example of genotype and environment interaction in the development of deep venous thrombosis]

A young woman, carrying factor V Leiden, developed a deep venous thrombosis after the use of oral contraceptives. This suggests that it is appropriate to study the most frequent causes of primary thrombophilia in all of the women beginning a treatment with estrogens.

Acute pancreatitis and deep vein thrombosis associated with HELLP syndrome

The HELLP syndrome (HS) belongs to the list of obstetric complications believed to be associated with coagulation disorders. It was formerly thought that chronic intravascular clotting (DIC) in the placental vessels was the main cause. A hypercoagulable state has been reported in cases of severe HS associated with microvascular abnormalities that may involve cerebral, placental, hepatic and renal vessels. A case of acute pancreatitis and DVT of inferior cava in a pregnant woman, presenting with HS at 29 weeks, who was found to have a R506Q mutation, is reported. Preeclampsia-associated pancreatitis and DVT have rarely been reported. It is hypothesized that APC-R and Factor V Leiden mutation may prove to be new and more important markers capable of predicting a more significant maternal morbidity associated with HS. Thrombosis prophylaxis may be considered during pregnancy in order to reduce hazardous multiorgan failure (MOF) in women who are heterozygous for Factor V Leiden mutation.

The levels of the plasma coagulation factors after trauma and childbirth

The levels of the plasma coagulation factors are raised in the post-traumatic and post-partum periods. Factors, I, VIII, IX, and X were raised in two groups, one of patients after trauma, the other of patients after childbirth, while factors V and VII were raised in the puerperal group only. The relationship between these changes and thrombosis in vivo is discussed.

The assay and properties of labile factor (factor V)

Human oxalated plasma stored at 4 degrees C. until the prothrombin time is increased beyond 60 sec. is a reliable medium for assaying labile factor (factor V) because its response to added labile factor corresponds quantitatively to that of plasma from patients with congenital deficiency of this factor. Such an agreement is not obtained with plasma stored at 37 degrees C. The stability of labile factor is closely associated with ionized calcium. The addition of thrombin to fresh oxalated plasma causes an apparent hyperactivity of labile factor, but this is completely removed by adsorption with Ca(3)(PO)(2). Oxalated plasma when adsorbed with Ca(3)(PO(4))(2) before treatment with thrombin does not develop this adventitious activity, nor does it occur in stored plasma treated with thrombin. The seemingly high labile factor activity in serum can be explained by the activation of this factor which is independent of labile factor but acts synergistically with it. The true labile factor concentration can be determined only after the accelerator is removed by adsorption with Ca(3)(PO(4))(2). A close agreement between the consumption of prothrombin and the loss of labile factor during clotting is observed.

Genetic abnormalities of the protein C system: shared risk factors in young adults with migraine with aura and with ischemic stroke?

Migraine, particularly migraine with aura (MA), may be a risk factor for ischemic stroke (IS). The reasons for this association are unknown. We investigated the presence of genetic abnormalities of the protein C system in 83 MA patients, 31 IS patients, and 124 healthy controls, all aged under 45 years. We found an increased frequency of activated protein C resistance due to Arg506Gln factor V mutation, and of protein S deficiency in both disorders, with figures higher than those reported in the general population and significantly different from those found in controls. These prothrombotic genetic abnormalities may be shared risk factors in IS and MA, and may play a role in increasing the risk of cerebrovascular disease in migraineurs.

Is hormone replacement a risk factor for ischemic stroke in women with factor V Leiden mutation?

OBJECTIVE

To describe a patient with multifocal cerebral ischemia whose only identified potential risk factors were use of postmenopausal hormone replacement and heterozygosity to factor V Leiden mutation.

DESIGN

A case report.

SETTING

A tertiary care center.

PATIENT

A 51-year-old woman taking hormone replacement (0.625 mg/d of estrogen alternating with 10 mg/d of medroxyprogesterone) presented with a generalized tonic-clonic seizure. She had persistent multifocal non-enhancing lesions on magnetic resonance imaging of the brain. A stereotactic biopsy of the brain performed to exclude gliomatosis cerebri was consistent with cerebral ischemia. An extensive evaluation to uncover the cause of stroke revealed only heterozygosity to factor V Leiden mutation.

MAIN OUTCOME AND RESULTS

Hormonal replacement was discontinued and the patient had no recurrent ischemic strokes.

CONCLUSIONS

Postmenopausal hormonal replacement may be a risk factor for ischemic stroke in women with the factor V Leiden mutation. Ongoing trials of hormonal replacement provide an opportunity to test this hypothesis.

The role of activated protein C resistance in the pathogenesis of venous thrombosis

Venous thromboembolism (VTE) is the third most common cardiovascular disease in the United States. VTE is usually a consequence of either acquired or inherited alterations in hemostatic regulatory proteins. These regulatory proteins are predominantly those of the protein C/protein S natural anticoagulant pathway. Acquired deficiencies in this pathway are frequently a consequence of other clinical entities (eg, cancer, AIDS, and diabetes), while inherited deficiencies can be responsible for venous thrombosis in an otherwise healthy individual. The purpose of this article is to briefly describe the pathobiology of the anticoagulant protein system and to review the clinical implications of activated protein C resistance.

Risk of stroke in young women and two prothrombotic mutations: factor V Leiden and prothrombin gene variant (G20210A)

BACKGROUND AND PURPOSE

Factor V Leiden and a prothrombin gene variant, G20210A, are mutations associated with a thrombotic risk. The aim of our study was to assess whether these mutations increase the risk of stroke in women under 45 years of age.

METHODS

We conducted a case-control study in western Washington state. Case patients were women aged 18 to 44 years with a first stroke (n = 106). Control subjects were women without stroke recruited from the same region by use of random-digit telephone dialing (n = 391). All were interviewed and provided blood specimens, which were genotyped for these mutations.

RESULTS

Factor V Leiden was found in 0.9% of case patients, a single patient with a subarachnoid hemorrhage, and in 4.1% of control subjects. The odds ratio (OR) for any stroke was 0.2 (95% confidence interval [CI], 0.03 to 1.7). The prothrombin variant was found in 1.9% of case patients, 1 with a venous stroke and 1 with an ischemic stroke, and in 1.6% of control subjects. The OR for any stroke was 1.48 (95% CI, 0.14 to 9.17). ORs for stroke types were also not statistically significant.

CONCLUSIONS

In this study, neither factor V Leiden nor the prothrombin variant (G20210A) was an important risk factor for stroke in young women. In this setting, screening for these mutations cannot be recommended. Unanswered by this study is whether screening would be useful in select patients, such as those with a strong family history of thrombophilia or those with venous strokes.

Stroke and steroid hormonal contraception

The rate of stroke in young women has been falling for some years. The data presented here suggest that the relative risk associated with oral contraceptive use also is falling. This is probably due to a combination of younger age at use of oral contraceptives, lower steroid dose of preparations, and more systematic screening of potential users; particularly with respect to blood pressure. The risk associated with oral contraceptive use is greater for occlusive stroke but increases with age in hemorrhagic stroke. Risk of occlusive stroke increases with increasing doses of estrogen. The evidence for a risk related to type or dose of progestogen is less consistent, but there is no support for an increase in risk associated with use of desogestrel or gestodene.

Factor V Leiden and the risk of proximal venous thrombosis after total hip arthroplasty

Deep vein thrombosis (DVT) remains a major cause of morbidity in patients undergoing total hip arthroplasty (THA). Despite postoperative DVT prophylaxis, 20-50% of THA patients still develop DVT. Currently, there is no accurate way of predicting which patients will develop DVT despite standard prophylaxis. The presence of factor V Leiden is the most common cause of inherited DVT risk. It has been postulated that patients who have factor V Leiden and are subjected to thrombogenic stressors such as THA would have an increased risk of thrombosis. The factor V Leiden genotype of 36 patients who developed proximal DVT after surgery and 45 control patients who had THA but did not develop DVT was determined. All patients had had prophylaxis against thrombosis using intermittent pneumatic compression alone or in combination with warfarin or aspirin. Surveillance for proximal DVT was performed on all patients prior to discharge by duplex ultrasound. The 2 groups were similar in age, sex, and type of operation. Three of 36 study patients who had developed DVT (8%) and 2 of 45 control patients who had not developed DVT (4%) were heterozygotes for factor V Leiden; these prevalences were not statistically different. Heterozygosity for factor V Leiden is not associated with DVT prophylaxis failure in patients undergoing THA.

Third-generation oral contraceptive and deep venous thrombosis: from epidemiologic controversy to new insight in coagulation

Four epidemiologic studies showed a twofold increase in risk of deep venous thrombosis with the use of oral contraceptives containing third-generation progestins, relative to second-generation products. These findings have been strongly debated ever since, and new studies have been added. In the current article we examine whether the findings can be explained by potential biases or other shortcomings of the epidemiologic studies. We conclude that complete certainty cannot exist but that the most rational conclusion from the epidemiologic findings and their discussion is that an increased risk of deep venous thrombosis with third-generation contraceptives is likely, especially in first-time and young users. The controversy has recently led to new insights in coagulation: Women who use third-generation contraceptives acquire a resistance to the blood's own anticoagulation system, similar to the activated protein C resistance that is seen in persons who carry the factor V Leiden mutation but different from that in women using second-generation contraceptives.

Recurrent venous thromboembolic disease and factor XI concentrate in a patient with severe factor XI deficiency, chronic myelomonocytic leukaemia, factor V Leiden and heterozygous plasminogen deficiency

There are increasing concerns about the potential thrombogenic risks associated with the use of factor XI concentrates. We describe the case of a 49 year-old man with chronic myelomonocytic leukaemia and severe factor XI deficiency (< 1 u/dl), in whom the use of factor XI concentrate appeared to be associated with the development of venous thromboembolic disease. Subsequent investigations revealed the presence of both the factor V Leiden abnormality and heterozygous plasminogen deficiency. This case highlights the risks associated with the use of factor XI concentrates and suggests that these risks may be further increased in patients with an inherited or acquired prothrombotic abnormality or an underlying malignancy. Prothrombotic screening of patients with severe factor XI deficiency may be indicated particularly in younger patients in whom treatment with factor XI concentrates is a possibility.

COAGULATION AND FIBRINOLYSIS IN INJURED PATIENTS

Serial changes in coagulation and fibrinolysis studied among 42 patients admitted to hospital with a wide variety of injuries are reported. The first hours after trauma are dominated by an acceleration of fibrinolysis (clot lysis) and clotting time which are often followed by an abrupt rebound to prolonged fibrinolysis and normal clotting. Evidence is presented that acceleration of fibrinolysis is due to flooding of the circulation by plasminogen activator and that prolongation is probably due to an inhibitor. A prolonged prothrombin time, increased prothrombin consumption index, an acceleration of the heparin-retarded clotting time, and a fall in the platelet count are also frequent during the first hours after injury. There is evidence also of an early deficiency in factor V and the onset of a fall in factor VII and prothrombin. The following days are characterized by continued prolongation of fibrinolysis, a lengthening of clotting time, and an increased prothrombin consumption index suggestive of a defect in thrombo-plastin generation. Subsequent periods of prolonged fibrinolysis may develop. Prothrombin time often continues prolonged for one to three weeks and may vary phasically; plasma prothrombin and factor VII are reduced but there is now little change in factor V. The platelet count continues to fall for one to three days, then a thrombocytosis develops, often with abnormally high platelet levels, a week or so later. Plasma fibrinogen rises within 24 hours to reach a plateau maximum a few days later and levels remain high for prolonged periods in the severely injured. Various changes are related to or influenced by the severity of trauma. Mechanisms are discussed, including thrombosis in vivo, and reference is made to homeostatic significance and its possible breakdown.