Heparinoid anticoagulation and topical fibrin sealant in heparin-induced thrombocytopenia

Anticoagulant drug utilization pattern and their cost analysis: a retrospective study from Saudi Arabia

Objective

The study was aimed to evaluate the cost and drug utilization pattern of anticoagulant drugs in a clinical setting in Saudi Arabia.

Method

A cross-sectional retrospective study was conducted in a private hospital in Saudi Arabia. World Health Organization, defined daily dose, and American Society of Hematology methods were used to compute the daily price of each anticoagulant agent.

Key findings

Consumption of oral anticoagulants was very less as compared to the parenteral. Apixaban was the most prescribed oral drug, while enoxaparin sodium was the drug of choice among the parenteral. In oral anticoagulants, the unit-wise cost was found to be highest for Rivaroxaban (12.60 SR (3.36 USD) and less for Warfarin (0.82 SR (0.22 USD)). Heparin sodium cost (51.62 SR (13.76 USD) was found to be the most expensive parenteral agent while the least expensive was Phytomenadione (3.76 SR (1.00 USD)).

Conclusion

Apixaban was the preferred oral anticoagulant among all the studied anticoagulants, although Warfarin is the cheapest. Therapeutic drug monitoring was recommended for Warfarin. The study highlights the importance of more studies to measure the advantages and disadvantages of all types of anticoagulants.

Management of haemostasis in surgery: sealant and glue applications

Blood loss has always been a sensitive issue in surgery. Traditional techniques, such as suturing and electrocautery, have drastically reduced operatory bleeding. Unfortunately, wound edges and point application devices are frequently characterized by bleeding and infections. Over the past 20 years, haemostatic agents and tissue sealants have been developed and now are currently used, along with classic suture in various surgical specialties. Their fluid nature allows management of blood loss along any point of the wound and tissue repair. This review presents an overview of the most diffused haemostatic sealants, focusing on their main use in surgery and their adverse effects.

Diagnosis and management of heparin-induced thrombocytopenia

Heparin use is ubiquitous, wherein 1 to 5% of patients exposed to standard unfractionated heparin develop thrombocytopenia due to antibodies to a complex of heparin and platelet factor 4. Classic features include onset of thrombocytopenia after 5 to 10 days of ongoing heparin exposure, a 50% fall in the platelet count from baseline, resolution of the thrombocytopenia 5 to 10 days after cessation of heparin and a high risk of thrombosis noted in 30 to 75% of patients with heparin-induced thrombocytopenia (HIT) in terms of every-other-day platelet-count monitoring in patients on standard unfractionated heparin. And those patients developing thrombocytopenia necessitate an accurate, readily accessible diagnostic test for HIT. Diagnosis has been recently facilitated by the development of an enzyme-linked immunosorbent assay (ELISA) test for the heparin-P4 antibody complex, although this test carries a relatively low specificity. Widespread use of the ELISA demonstrates a relatively high prevalence of the antibody in patients exposed to heparin in certain settings, such as cardiopulmonary bypass, wherein a quarter of patients have a positive ELISA of unclear significance. Once HIT is diagnosed, the high risk of thrombosis necessitates empiric anticoagulation with an antithrombin such as argatroban or lepirudin, or the heparinoid danaparoid. Additional agents under further study include the antithrombin bivalirudin and the pentasaccharide fondaparinux. Future issues in HIT include increasing awareness for HIT, improving the specificity of HIT testing and the development of new anticoagulants for HIT that will enable out-patient management.

Use of plasma exchange and heparin during cardiopulmonary bypass for a patient with heparin induced thrombocytopenia: a case report

Patients with documented history of heparin-induced thrombocytopenia (HIT) pose a difficult problem during surgery using cardiopulmonary bypass (CPB). Several alternatives to heparin exist, but these products either are not approved for use in the United States or have more side effects than heparin. We report on a patient with documented heparin-induced antibody and left main coronary artery disease who underwent uneventful coronary artery bypass surgery and recovery by using preoperative plasmaphresis and limited use of porcine intestinal heparin during CPB.

Fibrin sealants in surgical practice: An overview

The need to effectively manage hemostasis and tissue sealing during surgery has had a strong influence on the development of modern surgical techniques. A group of agents known as surgical tissue adhesives has been developed to promote hemostasis and tissue sealing during surgery, and these comprise both natural and synthetic agents. Fibrin sealants are the most effective tissue adhesives currently available, and they are biocompatible and biodegradable. The fibrin sealants are comprised of purified, virus-inactivated human fibrinogen, human thrombin, and sometimes added components, such as virus-inactivated human factor XIII and bovine aprotinin. These agents mimic the final steps of the physiological coagulation cascade to form a fibrin clot. The use of any plasma-derived product in the surgical setting carries a potential risk of viral transmission. In fact, it was the risk of viral transmission from fibrinogen and thrombin that halted development work on fibrin sealants in the United States. Since that time, new techniques for isolating and concentrating plasma fractions have been developed, and national and international guidelines have been introduced to ensure the safety of all plasma products. All plasma donors are carefully selected and their plasma units screened for viral contamination before processing. All plasma donations and bovine tissue used in the production of commercial fibrin sealants undergo rigorous viral reduction/elimination steps. As a result of this carefully controlled and monitored process, there have been no proven cases of viral transmission associated with the use of commercial fibrin sealant. Fibrin sealants are currently used in a number of surgical specialties, including cardiovascular surgery, thoracic surgery, neurosurgery, plastic and reconstructive surgery, and dental surgery. The use of fibrin sealants has a positive effect on surgical outcomes, such as improved time to hemostasis, reduced blood loss, and reduced complications. This review describes the development of fibrin sealants, the composition of currently available products, and their use in surgical practice.

New and potential uses of fibrin sealants as an adjunct to surgical hemostasis

Commercially prepared fibrin sealants have been available in Europe and Japan for many years. However, current formulations are exclusively two-component, liquid fibrin sealants, and delivery devices are rather rudimentary. To date, this has had the effect of limiting the number of clinical applications that make use of fibrin sealants. The recent licensing of fibrin sealants by the Food and Drug Administration in the United States has the potential to expand the use of these products in established procedures. As surgeons gain experience with fibrin sealants, it is likely that new clinical applications will be developed in a wider range of surgical specialties. The aim of this article is to explore the potential future formulations and uses of fibrin sealants and highlight a range of surgical procedures that may benefit from these products.

The use of lepirudin for anticoagulation in patients with heparin-induced thrombocytopenia during major vascular surgery

The method of anticoagulation in patients undergoing major vascular surgery with a history of heparin-induced thrombocytopenia (HIT) is controversial. We present two cases in which a bolus only technique using recombinant hirudin (Lepirudin or Refludan) was used successfully in patients with HIT scheduled for vascular surgery.

Platelets: an update on diagnosis and management of thrombocytopenic disorders

Thrombocytopenia in the pregnant patient may result from a number of causes, most of which involve either immune-mediated platelet destruction or platelet consumption. Many of these disorders share clinical and laboratory features, making accurate diagnosis difficult. Moreover, uterine evacuation is indicated in the therapy of some disorders, while in others alternative interventions may allow the pregnancy to be carried to term. These and other issues are discussed as part of a comprehensive review of the differential diagnosis and management of thrombocytopenia in pregnancy. The term "refractory ITP" is used with reference to two distinct groups of patients: 1) patients in whom the platelet count cannot be easily increased, including those who are poorly responsive to initial single agent treatment, and 2) those with persistent thrombocytopenia despite the use of conventional therapies. An approach to management of the former group will be presented, followed by a discussion of patients with chronic refractory ITP. The latter will include presentation of new data on the role of Helicobacter pylori in ITP and whether its treatment ameliorates thrombocytopenia, as well as the use of rituximab and other modalities. Thrombotic microangiopathies such as thrombotic thrombocytopenic purpura (TTP) are rare, but life threatening causes of thrombocytopenia. Ultra-large multimers of von Willebrand factor (vWF) aggregate platelets intravascularly, and congenital or immune-mediated deficiencies of a metalloprotease that cleaves these ultra-large multimers may cause TTP. However, little information exists concerning the behavior of this protease in other physiological and pathological conditions. Levels of this protease have now been measured in healthy individuals of different ages, full-term newborns, pregnant women and a patients with variety of pathologic conditions, and these data will be reviewed herein. Heparin-induced thrombocytopenia/thrombosis (HIT/T) remains the most common antibody-mediated, drug-induced thrombocytopenic disorder, and a leading cause of morbidity and mortality. Based on clinical correlations and murine models, there is increasing evidence that antibodies to complexes between platelet factor 4 (PF4) and heparin cause HIT/T, and the molecular composition of the relevant antigen has also become better defined. However, the introduction of sensitive ELISAs to measure anti-PF4/heparin antibodies has complicated diagnosis in some settings in which the incidence of such antibodies in unaffected patients exceeds the incidence of the disease. In addition, the FDA approval of Lepirudin and Argatroban has expanded the repertoire of agents available for therapy of HIT/T and may change the approach to management of asymptomatic patients with thrombocytopenia. However, the optimal use of these drugs in commonly encountered settings remains in evolution, and a need for alternative approaches to prevention and treatment is evident.

Efficacy of a novel hemostatic agent in animal models of impaired hemostasis

This study evaluated the efficacy of a novel sprayable hemostat under both normal conditions and those of compromised coagulation. CoStasistrade mark Surgical Hemostat ("CoStasis"), containing collagen, thrombin, and autologous plasma, was compared to Instattrade mark collagen sponge, an investigational fibrin sealant, and a no treatment control, for the ability to control bleeding in a rabbit kidney model. Hemostatic performance was determined by time to hemostasis and blood loss in a nonsurvival, randomized, in vivo bleeding rabbit kidney model. Under conditions of normal coagulation, as well as aspirin and heparin treatment, hemostasis was achieved faster with CoStasistrade mark than with Instattrade mark and fibrin sealant. With the exception of the time to hemostasis using Instattrade mark sponge in heparinized rabbits, all differences were statistically significant (p < 0.03, Wilcoxon). Blood loss, where measured, was lower with CoStasistrade mark than with the other hemostats under the three coagulation conditions. Statistical significance, (p < 0.03, Wilcoxon), was achieved with all comparisons except with fibrin sealant in aspirin treated animals. The combination of collagen, thrombin, and autologous plasma used in CoStasis, can achieve significantly faster hemostasis than the conventional atraumatic hemostats, collagen sponge, and fibrin sealant under normal conditions and conditions of impaired hemostasis.

Heparin-induced thrombocytopenia and thrombosis

Heparin remains the most commonly used parenteral medication in hospitalized patients. Heparin induced thrombocytopenia (HIT) and heparin induced thrombocytopenia with thrombosis syndrome or the white clot syndrome are important complications of heparin use. This article provides an in-depth review of the etiopathogenesis, clinical manifestations, diagnosis, and management options in patients with HIT. Clinical problems associated with HIT such as antiphospholipid antibody syndrome and venous gangrene are described. The management options of HIT patients during cardiac interventional procedures and coronary surgery as well as recent advances in therapeutic options are summarized.

Fibrin sealant in preclinical and clinical studies

Fibrin sealant, now commercially available in the United States, is a virally inactivated preparation of highly purified human fibrinogen and human thrombin that includes aprotinin to reduce fibrinolysis. Although the product is relatively expensive, cost can be justified when the sealant is used to produce localized hemostasis in surgery in which bleeding cannot be controlled by sutures. Fibrin sealant can also be justified as an alternative to factor concentrates in patients with coagulopathies who have a localized site of bleeding. Newer formulations of fibrinogen and thrombin in a freeze-dried form applied as a bandage may be useful in immediate, on-site treatment of trauma victims in either a civilian or military setting.