Thrombosis in a duplicated superficial femoral vein in a patient with haemophilia A

Activated protein C resistance in the copresence of emicizumab and activated prothrombin complex concentrates

Background

Venous thromboembolic events have been reported in persons with hemophilia A who received emicizumab and activated prothrombin complex concentrate (APCC) concomitantly, but the relevant mechanism(s) remains unclear. We speculated that activated protein C (APC) and antithrombin (AT) resistance might be associated with these adverse events.

Objectives

To investigate APC and AT resistance in factor (F)VIII-deficient (FVIIIdef) plasma in the presence of emicizumab and APCC.

Methods

In pooled normal plasma or FVIIIdef plasma samples mixed with emicizumab (50 μg/mL) and FVIII-bypassing agents, including recombinant FVIIa (2.2 μg/mL), APCC (1.3 IU/mL), or plasma-derived FVIIa/FX (1.5 μg/mL), the suppression effect of AT (0-2.4 μM) and APC (0-16 nM) was assessed by tissue factor-triggered thrombin generation assay. The APC effects in FVIIIdef plasma with the copresence of emicizumab, FII (1.3 μM), and/or FIXa (280 pM) were also examined.

Results

The AT resistance in emicizumab and each bypassing agent was not observed. Moreover, APC dose-dependent suppression effect was observed in pooled normal plasma or FVIIIdef plasma mixed with emicizumab and recombinant FVIIa or plasma-derived FVIIa/FX. However, APC-catalyzed inactivation had little effect on thrombin generation assay potential in FVIIIdef plasma spiked with emicizumab and APCC. The addition of FIXa to emicizumab in FVIIIdef plasma could lead to partial APC resistance. Furthermore, FVIIIdef plasma spiked with emicizumab, FIXa, and FII was markedly resistant to APC-mediated inactivation.

Conclusion

FII and FIXa in APCCs were key clotting factors for APC resistance in FVIIIdef plasma supplemented with emicizumab and APCCs. The APC resistance in persons with hemophilia A receiving emicizumab and APCC may contribute to venous thromboembolic events.

Extensive but minimally symptomatic deep vein thrombosis in duplicated femoral veins

Duplicated femoral veins predispose to venous thrombosis, but patients may present with minimal/no symptoms. The required length of treatment is unclear, but periodic ultrasound surveillance may play a role in the absence of definitive treatment options.

[Thrombotic events in patients with hemophilia]

The paper describes 4 clinical cases of thrombotic events (pulmonary embolism, deep vein thrombophlebitis, acute myocardial infarction, ischemic stroke) that have occurred in patients with hemophilia. It discusses the possible causes of their development and methods for their prevention and treatment. Controlled natural hypocoagulation, in which the dose of an administered deficient factor decreases to such an extent that in order to maintain the safe level of hypocoagulation (plasma factor activity is 15-20%; activated partial thromboplastin time is 1.5-2 times normal values), is proposed as one of the treatment options.

Upper Limb Deep Vein Thrombosis in Patient with Hemophilia A and Heterozygosity for Prothrombin G20210A: A Case Report and Review of the Literature

Deep vein thrombosis (DVT) is a rare disease in patients with hemophilia A. We report a case of 22-year-old male with severe hemophilia A who presented to the emergency room with 5-day history of right arm pain that was attributed initially to bleeding event. In the absence of external signs of bleeding or hematoma and normal hemoglobin level, we suspected an underlying DVT. Doppler ultrasonography of the right upper limb revealed thrombosis of the subclavian vein and this was confirmed by CT venography. The d-dimer level was normal and investigations for prothrombotic state revealed heterozygosity for prothrombin G20210A mutation. Treatment with factor VIII and low molecular weight heparin led to successful resolution and marked improvement of his clinical condition.

Sequential thrombosis and bleeding in a woman with a prolonged activated partial thromboplastin time

Simultaneous or sequential haemorrhage and thrombosis in the presence of a prolonged activated partial thromboplastin time (aPTT) is a rare occurrence: we describe the case a 37 year old lady who developed post-delivery deep vein thrombosis treated with low molecular heparin and warfarin followed a week later by extensive bruising over legs and forearms, a significant drop in haemoglobin and a very prolonged aPTT. Further tests revealed an acquired factor VIII inhibitor at 35 Bethesda Units. We discuss the clinical and laboratory implications and provide a literature review of simultaneous thrombophilia and haemophilia in the presence of a prolonged aPTT.

Single intravenous administration of TB-402 for the prophylaxis of venous thromboembolism after total knee replacement: a dose-escalating, randomized, controlled trial

BACKGROUND

TB-402 is a novel anticoagulant monoclonal antibody with a prolonged antithrombotic effect resulting from its partial factor (F)VIII inhibition and long half-life. We evaluated the efficacy and safety of a single administration of TB-402 for the prevention of venous thromboembolism (VTE) after total knee replacement (TKR).

PATIENTS AND METHODS

This was a phase II, dose-escalating, randomized, enoxaparin-controlled, open-label study. Patients were post-operatively assigned to a single dose of TB-402 (0.3, 0.6 or 1.2 mg kg(-1)) or enoxaparin 40 mg for at least 10 days (n = 75 per group; 3:1 TB-402 to enoxaparin). The primary efficacy outcome was total VTE defined as asymptomatic deep vein thrombosis (DVT) detected by bilateral venography and symptomatic VTE by day 7 to 11. The principal safety outcome was the incidence of major bleeding and clinically relevant non-major bleeding.

RESULTS

Total VTE was lower in all TB-402 groups compared with enoxaparin: 16.7%(95% CI 9.8-26.9), 23.9%(95% CI 15.3-35.3), 24.1%(95% CI 16.0-34.5) and 39.0%(95% CI 28.8-50.1) for TB-402 0.3, 0.6, 1.2 mg kg(-1) and enoxaparin, respectively (P = 0.003 for TB-402 0.3 mg kg(-1) vs. enoxaparin). The incidence of total VTE in the pooled TB-402 groups was 21.6% (95%CI 16.6-27.5), an absolute risk reduction vs. enoxaparin of 17.4% (95% CI 5.2-29.6). Major or clinically relevant non-major bleeding was observed in 3/75(4.0%), 4/74(5.4%), 7/87(8.0%) and 3/79(3.8%) patients for TB-402 0.3, 0.6, 1.2 mg kg(-1) and enoxaparin, respectively.

CONCLUSIONS

TB-402, as a single post-operative administration, was associated with a lower rate of VTE in all doses tested, compared with enoxaparin. The incidence of major and clinically relevant non-major bleeding was similar to enoxaparin 40 mg for TB-402 0.3 and 0.6 mg kg(-1).

Spontaneous deep vein thrombosis in hemophilia A: a case report

Venous thromboembolus is an important cause of hospital acquired morbidity and mortality. Venous thrombosis is a very rare occurrence in patients with haemophilia A. The thrombosis originated from the right main and external iliac veins, and effects the cranial segments of the main, deep and superficial femoral veins as an acute phase thrombus. Neither any local anatomic compression nor any predisposing thrombophilic risk factors were identified. We treated the patient with enoxaparine 1 mg/kg twice a day subcutaneously and then started oral anticoagulation with warfarin.

Spontaneous deep vein thrombosis in hemophilia A: a case report

Venous thromboembolus is an important cause of hospital acquired morbidity and mortality. Venous thrombosis is a very rare occurrence in patients with haemophilia A. The thrombosis originated from the right main and external iliac veins, and effects the cranial segments of the main, deep and superficial femoral veins as an acute phase thrombus. Neither any local anatomic compression nor any predisposing thrombophilic risk factors were identified. We treated the patient with enoxaparine 1 mg/kg twice a day subcutaneously and then started oral anticoagulation with warfarin.

A systematic overview of the first pasteurised VWF/FVIII medicinal product, Haemate P/ Humate -P: history and clinical performance

Patients with von Willebrand disease (VWD) and haemophilia A (HA) lack, to varying degrees, the von Willebrand factor (VWF) and coagulation factor VIII (FVIII) that are critical for normal haemostasis. These conditions in turn make patients prone to uncontrolled bleeding. Historically, patients with severe forms of VWD or HA were crippled before adulthood and their life expectancy was significantly reduced. Over the past decades, specific coagulation factor replacement therapies including Haemate P, have been developed to help patients achieve and maintain normal haemostasis. Haemate P is a human, plasma-derived VWF/FVIII medicinal product, which was first licensed in Germany in 1981 for the treatment of HA-associated bleeding. It has since then come to be accepted as the gold standard for both the treatment and prophylaxis of bleeding in VWD, especially in cases where desmopressin [1-deamino-8-D-arginine vasopressin (DDAVP)] has been ineffective. Haemate P was the first effectively virus-inactivated (pasteurisation: 60 degrees C for 10 h in aqueous solution) FVIII product, whereby the risk of potentially threatening infective complications of plasma-derived products was reduced. Haemate P was also shown to have a VWF multimer profile remarkably close to that of normal plasma. This bibliographic review presents previously unpublished clinical data of Haemate P, based upon internal clinical study reports of the proprietor, CSL Behring, in addition to data already presented in other publications. The data demonstrate a predictable and well-characterised pharmacokinetic profile, and a proven record of short- and long-term safety, while effectively correcting the haemostatic defects in VWD and HA. Recently available data have also shown Haemate P to be of haemostatic value in exceptional clinical circumstances including surgical interventions. By virtue of its plasma-derived combination of VWF and FVIII, in addition to its high VWF:FVIII content ratio (2.4:1), Haemate P is also associated with successful immune tolerance induction in those patients developing inhibitor antibodies. Although the theoretical risk of thromboembolic complications does exist while receiving Haemate P, as it does with any FVIII replacement therapy, the incidence of such complications has remained notably low. Given the robust data that have accumulated for the use of Haemate P, dosing recommendations are also described in this review; the recommendations are tailored to patient-specific contexts including baseline VWF and FVIII levels in plasma and the type of surgical intervention being undertaken. A wide variety of studies have also provided data on paediatric and geriatric populations, all of which have suggested that Haemate P can be safely and effectively used in a wide variety of clinical circumstances.

Non-catheter associated venous thrombosis in hemophilia A and B. A critical review of all reported cases

All reported cases of non-catheter induced venous thrombosis in patients with hemophilia A or B have been carefully evaluated. A total of 27 cases were reported,12 patients with hemophilia A and 15 patients with hemophilia B. The age of patients varied between 9 and 67 years. There were 10 cases of deep vein thrombosis, 8 patients with pulmonary embolism accompanied or not by deep vein thrombosis, 5 cases of superficial vein thrombosis. In addition, there were 3 cases of thrombosis in unusual sites (1 retinal central vein thrombosis and 2 portal vein thrombosis). Finally, in one case, venous thrombosis was multiple. There was a fatality in a hemophilia B patient with pulmonary embolism. The most frequent risk or triggering factor in hemophilia A was the administration of Feiba or rFVIIa concentrates in patients with inhibitors. Surgery together with Prothrombin Complex concentrates was the most frequent cause in hemophilia B patients. Congenital associated prothrombotic risk factors were present in two patients. No or very few therapeutic procedures were initiated in these patients but for a suspension or reduction of concentrates infusion. In a few instances low molecular weight heparin was given for a few days. The frequent association of venous thrombosis with infusion of concentrates indicates the need for a careful evaluation of patients about to receive such therapy.

Bilateral duplicated internal jugular veins: Case study and literature review

A rare bilateral duplication of the internal jugular vein (IJV) was discovered during cadaveric dissection. From each jugular foramen, a single IJV descended to the level of the hyoid bone then divided into medial and lateral veins. The medial IJVs traveled in the carotid sheath; the lateral IJVs coursed posterolateral to the sheath across the lateral cervical region (posterior triangle) of the neck. On the right side, medial and lateral IJVs entered the subclavian vein separately. C2-C3 anterior rami and the suprascapular artery passed between the medial and lateral IJVs. The right external jugular vein passed aberrantly between the heads of the sternocleidomastoid muscle (SCM) into the subclavian vein anterior to the lateral IJV. On the left side, the medial IJV drained into a large bulbous jugulovertebrosubclavian (JVS) sinus that received six main vessels. The lateral IJV diverged posterolaterally toward the border of the trapezius muscle, received the transverse cervical vein, and then turned sharply anteromedially to drain into the JVS sinus. The lateral IJV also gave an aberrant additional large vein that passed laterally around the omohyoid muscle before entering the JVS sinus. The left external jugular vein paralleled the anterior border of SCM before passing posterolaterally to terminate in the JVS sinus. Jugular vein anomalies of this magnitude are very rare. Determining the frequency of multiple IJVs is hampered by inconsistent terminology. We suggest that IJV duplication differs from fenestration anatomically and, potentially, developmentally. Criteria for characterizing IJV duplication and fenestration are proposed. The mechanism of development and the clinical significance of multiple IJVs are discussed.

Classic polyarteritis nodosa presenting rare clinical manifestations in a patient with hemophilia A

A 35-year-old patient with hemophilia A presented with rapidly progressive polyarteritis nodosa (PAN). He had been infected with hepatitis B virus (HBV) by repeated transfusion and was positive for hepatitis B surface antigen but negative for hepatitis B surface antibody. The patient presented symptoms of acute epididymitis followed by emergency admission because of acute appendicitis. On day 7 of admission, he complained of severe back pain, and computerized tomography (CT) showed massive perirenal hematoma. On day 49, mild monoplegia in the left arm suddenly developed, and CT and magnetic resonance imaging revealed multiple cerebral infarctions. Factor VIII replacement therapy was attenuated; however, cerebral infarction was progressive and extended throughout the cerebral hemispheres. He was diagnosed with classic polyarteritis nodosa (cPAN), and pulse methylprednisolone was continued. The patient died of supratentorial herniation, and autopsy revealed that vasculitis associated with intimal thickening was present in the liver, pancreas, intestine, kidneys, and larger-sized cerebral arteries. The development of cPAN appeared to have originated from chronic HBV infection, and this is the first report of cPAN in hemophilia patients. Concomitant hemorrhagic and thrombotic manifestations of cPAN are hardly treatable in patients with coagulation disorders, and the current case may represent a rare transfusion-related complication in hemophilia patients.

Fatal postoperative pulmonary embolism in mild haemophilia

The use of thromboprophylaxis in patients with haemophilia receiving factor replacement is often not considered necessary, but remains an area of debate. In this report we describe a patient with mild haemophilia A, who underwent major pelvic surgery. He had several underlying risk factors associated with the development of thromboembolism, and ultimately died as a direct consequence of multiple pulmonary emboli. The need for thromboprophylaxis and the risk balance ratio should always be considered in patients with bleeding disorders if they fall into what would otherwise be high-risk category for hospital acquired venous thromboembolism.

Deep vein thrombosis in a patient with severe haemophilia A

A 25-year-old male with severe haemophilia A developed deep vein thrombosis of the left upper limb. Venography showed thrombosis of the basilic vein. There was no underlying prothrombotic condition. He was successfully treated with low-molecular weight heparin.

Pulmonary embolism in a patient with severe congenital deficiency for factor V during treatment with fresh frozen plasma

Thrombosis is a rare complication in patients with congenital clotting factor deficiencies. In most cases, it is related to inherited procoagulant factors, use of central venous catheters or administration of coagulation factor concentrates. There are only a few case reports about thrombotic events during treatment with fresh frozen plasma (FFP). We report the case of a patient with homozygous inherited factor V deficiency, who developed a pulmonary embolism at a time of treatment with methylene blue treated FFP (MBFFP). The patient had only two other factors predisposing to thrombosis and both were acquired: obesity and bed rest. He started anticoagulant treatment with low molecular weight heparin (LMWH) while the deficient factors were replaced with MBFFP. After 8 days of treatment the patient developed a severe respiratory insufficiency. Pulmonary haemorrhage was considered among the differential diagnosis and LMWH was stopped. An inferior vena cava filter was placed without any further thrombotic complications. To our knowledge, there are no reports about patients with clotting factor deficiencies who developed a thrombotic event during treatment with MBFFP.

Haemophilia and thrombophilia: an unexpected association!

In patients with haemophilia, a close correlation is usually observed between the clinical expression of the disease and plasmatic factor VIII/factor IX clotting activity. However, some patients experience milder bleeding phenotypes than others, although they exhibit a similar biological profile. The high prevalence of some inherited thrombophilia risk factors offers the possibility of a co-inheritance in haemophilic patients which could influence the phenotypic expression of the disease. Rare thrombotic complications occurring in haemophiliacs could also be facilitated by the co-inheritance of modifier genes. The majority of thrombotic events occurring in haemophiliacs are in relation to clotting factor infusions or central venous catheters. Concerning surgical situations, in the absence of therapeutic recommendations, postoperative thromboprophylaxis is not systematically performed in haemophiliacs. However, substitutive treatment more or less completely corrects the coagulation defect and makes the venous thrombosis risk closer to the control population. It should be emphasized that haemophilia does not fully protect against venous thromboembolic disease. Patients with haemophilia very infrequently experience thrombotic events. Thus, the management of thrombotic complications occurring in haemophilic patients should be discussed in each case according to the precipitating risk factors, the clinical context and the thrombo-haemorrhagic balance of the patient with respect to a particular clinical situation.

Recombinant factor VIIa: review of efficacy, dosing regimens and safety in patients with congenital and acquired factor VIII or IX inhibitors

Recombinant factor (rF)VIIa has been available to clinicians since 1996 and has an excellent safety record after almost three-quarters of a million doses have been administered. This paper will review the current clinical experience with rFVIIa dosing in acquired and congenital hemophilia with inhibitors and chronicle all spontaneous and clinical trial reports of thrombotic adverse events as of April 2003. Standard dosing of rFVIIa (90 micro g kg(-1)) allows binding of FVIIa to the surface of an activated platelet and can directly activate factor X in the absence of tissue factor. Experience with bolus dosing suggests that higher dosing (>200 micro g kg(-1)) may be more efficacious in treating hemophilia patients. Clinical trials are ongoing to validate this observation. Continuous infusion dosing may be efficacious for major surgery but high infusion rates (50 micro g kg(-1) h(-1)) might be needed. The relationship between dose of rFVIIa, amount of thrombin generated and measurable FVIIa level is still not known and perhaps newer testing which measures thrombin generation might be more advantageous. Relatively few thrombotic events have been associated with rFVIIa. Known factors predisposing to thrombosis were present in 20 of the 25 (80%) hemophilia patients who were reported spontaneously or who developed a thrombosis during a clinical trial. Additionally, thrombotic events have not increased despite a growing experience with higher dosing of rFVIIa.

Spontaneous proximal deep vein thrombosis in a patient with severe haemophilia A

Venous thrombosis is a very rare occurrence in patients with haemophilia A. The majority of these cases occurred during or after the administration of clotting factor concentrates. We report the case of a patient with severe haemophilia A, who spontaneously developed a deep venous thrombosis (DVT). The thrombosis occurred in the superficial femoral vein with an extension in the profunda femoris vein. Neither any local anatomic compression nor any predisposing thrombophilic risk factors were identified. Treatment with recombinant factor VIII at prophylactic doses associated with unfractionated heparin led to a successful resolution. This case illustrates the possibility for severe haemophilia patients to develop authentic spontaneous DVT without anti-haemophilic treatment and predisposing risk factors.

The airline passenger: current medical issues

It is widely accepted that travel by air is unlikely to be a hazard to the vast majority of passengers. However, there are potentially adverse effects of cabin air of poor quality and of the reduced oxygen tension of the cabin environment. There is also the possibility of thrombosis related, at least in part, to the relative inactivity of a long journey. It may well be that the toxicity of the oil additives that are used in aircraft engines should be revisited, and that research should be carried out on the relative importance and potential interactions of the many risk factors for thrombosis that could be enhanced during a long flight. Formal guidelines need to be developed for passengers.

Simultaneous deep venous thrombosis and acquired factor VIII inhibitor

Acquired hemophilia A is a life-threatening immune-mediated hemorrhagic disorder that is most often found in individuals older than 50 who present with an unexplained activated partial thromboplastin time (aPTT) prolongation and clinically significant bleeding. The prolonged aPTT associated with acquired hemophilia A reflects factor VIII activity deficiency due to neutralizing or clearing autoantibodies. Deep venous thrombosis, in contrast, is a veno-occlusive disorder associated with several distinct hypercoagulable states that can result in significant morbidity and mortality due to pulmonary embolism, thrombus extension, and the post-thrombotic syndrome. A prolonged aPTT in the setting of thrombosis may reflect the presence of a lupus anticoagulant. In the absence of accurate diagnosis and the immediate institution of specific therapy, both disorders can be fatal. Three cases of acquired factor VIII inhibitors that included a prolonged aPTT, bleeding, and duplex ultrasound evidence of deep venous thrombosis are presented. The diagnostic and therapeutic challenges posed by these cases as well as a proposed mechanism by which pathologic thrombosis can develop in a patient with a life-threatening bleeding disorder are discussed.

Antithrombotic effects of controlled inhibition of factor VIII with a partially inhibitory human monoclonal antibody in a murine vena cava thrombosis model

The human monoclonal antibody mAb-LE2E9 partially inactivates human factor VIII (FVIII), leaving approximately 10% residual activity. The antithrombotic efficacy of the antibody was evaluated in mouse models of inferior vena cava thrombosis. Thrombi were induced in wild-type mice given either the antibody or saline. No thrombi occurred in any of 8 mice treated with mAb-LE2E9, whereas 6 of 8 control mice developed thrombi (P =.007). Treatment with mAb-LE2E9 did not result in a severe bleeding phenotype: a tail-cutting experiment that resulted in death of C57BL/6 FVIII-deficient (FVIII(-/-)) mice did not cause hemorrhagic death in mice treated with mAb-LE2E9. To evaluate the antithrombotic effect of mAb-LE2E9 in presence of human FVIII, thrombus formation was induced in FVIII(-/-) mice reconstituted intravenously with recombinant human FVIII (rhFVIII) or rhFVIII preincubated with mAb-LE2E9. Only 1 of 9 mice produced a thrombus in the rhFVIII/antibody complex-treated group, compared with 7 of 9 in the control group (P =.015). FVIII(-/-) mice were also reconstituted with rhFVIII and then injected with either mAb-LE2E9 or saline. One of 14 mice in the group treated with the antibody developed a thrombus, compared with 10 of 14 in the control group (P =.001). The thrombi occurring in antibody-treated animals were smaller than in controls (P <.01). All animals survived, and there were no bleeding complications. Thus, the mAb-LE2E9 antibody inhibits thrombosis without causing an overt bleeding tendency.