Oral anticoagulants as secondary prophylaxis of thrombosis in patients with polycythemia vera: a retrospective analysis of 15 patients

Polycythaemia Vera and Coronary Artery Bypass Graft Surgery: A Systematic Review of the Literature

OBJECTIVES

Polycythaemia vera (PV) is a condition that may potentially put patients undergoing cardiac surgery at an increased risk of bleeding and thrombosis; however, there is currently a paucity of literature regarding the management of these patients. We aim to examine the literature in this systematic review to indicate the interventions that may be considered to minimise complications.

METHODS

We conducted a literature search using keywords and MeSH terms to identify articles discussing PV and cardiac surgery. The studies were identified and qualitatively analysed using the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) protocol.

RESULTS

In total, 10 case reports representing 11 patients were identified for this systematic review and were included in qualitative analysis. 63.6% of patients had preoperative intermittent phlebotomy, and the majority of patients received postoperative therapy that involved one antiplatelet and one anticoagulant. Generous perioperative fluid management, phlebotomy, preservation of core body temperature, early extubation, monitoring of myocardial ischaemia, infarction and vascular events, intense chest physiotherapy and patient mobilisation are important to consider to reduce the risk of complications arising from surgery.

CONCLUSION

These considerations should be systematically discussed in a multidisciplinary team, where the acute surgical need can be balanced appropriately against the risk of haemorrhage and thrombosis.

Diagnosis, prevention, and management of bleeding episodes in Philadelphia-negative myeloproliferative neoplasms: recommendations by the Hemostasis Working Party of the German Society of Hematology and Medical Oncology (DGHO) and the Society of Thrombosis and Hemostasis Research (GTH)

Philadelphia-negative myeloproliferative neoplasms (Ph-negative MPN) comprise a heterogeneous group of chronic hematologic malignancies. The quality of life, morbidity, and mortality of patients with MPN are primarily affected by disease-related symptoms, thromboembolic and hemorrhagic complications, and progression to myelofibrosis and acute leukemia. Major bleeding represents a common and important complication in MPN, and the incidence of such bleeding events will become even more relevant in the future due to the increasing disease prevalence and survival of MPN patients. This review discusses the causes, differential diagnoses, prevention, and management of bleeding episodes in patients with MPN, aiming at defining updated standards of care in these often challenging situations.

Oral anticoagulation to prevent thrombosis recurrence in polycythemia vera and essential thrombocythemia

It is unclear whether anticoagulation guidelines intended for the general population are applicable to patients with polycythemia vera (PV) and essential thrombocythemia (ET). In the present study, the risk of thrombotic recurrence was analyzed in 150 patients with PV and ET treated with vitamin K antagonists (VKA) because of an arterial or venous thrombosis. After an observation period of 963 patient-years, the incidence of re-thrombosis was 4.5 and 12 per 100 patient-years under VKA therapy and after stopping it, respectively (P < 0.0005). After a multivariate adjustment for other prognostic factors, VKA treatment was associated with a 2.8-fold reduction in the risk of thrombotic recurrence. Notably, VKA therapy offset the increased risk of re-thrombosis associated with a prior history of remote thrombosis. Both the protective effect of VKA therapy and the predisposing factors for recurrence were independent of the anatomical site involved in the index thrombosis. Treatment periods with VKA did not result in a higher incidence of major bleeding as compared with those without VKA. These findings support the use of long-term anticoagulation for the secondary prevention of thrombosis in patients with PV and ET, particularly in those with history of remote thrombosis.

Thrombotic complications of myeloproliferative neoplasms: risk assessment and risk-guided management

Philadelphia-negative myeloproliferative neoplasms are considered to be acquired thrombophilic states. Thromboses, both arterial and venous (not rarely in unusual sites), are often the initial events leading to the diagnosis. After diagnosis, the yearly incidence of thrombotic events is highly variable, and ranges from approximately 1% to 10%. The identification of patients at risk who may benefit from antithrombotic therapy remains a challenge, and it is currently based on age and history of thrombotic events. However, the predictive value of these clinical characteristics is rather limited. Few prospective studies and even fewer interventional randomized studies are available, and there are no studies designed to formally validate the use of risk stratification. The implementation of laboratory parameters such as leukocytosis and/or the JAK2 V617F mutation into a scoring system may be of interest. The mechanisms at work leading to thrombosis remain largely speculative, but are likely to be complex and multifactorial, with a prominent role of cell-cell interactions, mostly owing to qualitative changes. The long-term treatment options to prevent thrombosis are, schematically, aspirin alone as primary prevention for the low-risk patients, and cytoreduction combined with aspirin for the other patients. In very low-risk young essential thrombocythemia patients, abstention can even be considered. The optimal duration of anticoagulation after a thrombotic event is not established. All antithrombotic therapies should be balanced with the hemorrhagic risk, which can also be increased in these patients.

Anticoagulation After Coronary Artery Surgery in Patients With Polycythemia Vera: Report of Two Cases

Polycythemia vera is a myeloproliferative disorder associated with the thromboembolic events. Normalization of the hematocrit and elevated platelet counts is obligatory to reduce the thrombotic risk of patients with PV. Therapeutic strategies include phlebotomy, myelosuppressive agents, and, more recently, interferon-alpha. In addition, appropriate antiplatelet therapy should be administered to prevent life-threatening complications and reducing the viscosity of the blood. Although aspirin is widely preferred in such patients, this monodrug therapy or combined with clopidogrel as an alternative approach might not be enough, especially after coronary artery surgery. Therefore, warfarin should be added to anticoagulant therapy. This short report describes the use of warfarin, associated with aspirin and clopidogrel as an anticoagulant regimen after coronary artery bypass surgery in two cases with polycythemia vera. We believe that a combination of warfarin with other oral antiplatelet agents may be more effective in preventing the coronary artery bypass graft thrombosis.

Budd-Chiari syndrome associated with hypereosinophilic syndrome; a case report

A 27-year-old man was admitted due to abdominal fullness. He had ascites and subcutaneous nodules on his head, with liver dysfunction and eosinophilia. Abdominal imaging revealed obstruction of the hepatic veins and stenosis of the inferior vena cava. Histological diagnosis of a subcutaneous nodule revealed obstructive thrombophlebitis with eosinophils. Tyrosine kinase created by fusion of the FIP1L1 and PDGFRA genes, which is characteristic of hypereosinophilic syndrome (HES), was detected. He was diagnosed with Budd-Chiari syndrome associated with HES. Liver function tests improved after interventional therapy followed by steroid therapy. It is important to diagnose the cause of Budd-Chiari syndrome.

Polycythemia Vera: Scientific Advances and Current Practice

Polycythemia vera (PV) is a clonal disorder of unknown etiology involving a multipotent hematopoietic progenitor cell that is characterized by the accumulation of phenotypically normal red blood cells, white blood cells, and platelets in the absence of a definable cause; extramedullary hematopoiesis, marrow fibrosis, and, in a few patients, transformation to acute leukemia can also occur. First described in 1892, the cause of the disease remains unknown and no potentially curative therapy other than bone marrow transplantation is currently available. It is commonly held that PV is a rare disorder, when in fact with a minimum incidence of 2.6 per 100,000 it is more common than chronic myelogenous leukemia (CML) and is particularly prevalent in persons of Ashkenazi Jewish ancestry. However, the incidence of PV is not as high as that of erythrocytosis from other causes collectively, which poses a problem in differential diagnosis when PV presents as isolated erythrocytosis. Characteristic features of PV are erythropoietin (Epo)-independent in vitro erythroid colony formation, as well as hypersensitivity to many other hematopoietic growth factors. Recently, a remarkable association between PV and a somatic point mutation of the JAK2 tyrosine kinase (JAK2 V617F) was described. Functional assays have revealed that JAK2 V617F is capable of inducing constitutive STAT5-mediated signaling in vitro, as well as erythrocytosis in vivo in mice. These data suggest that the JAK2 V617F mutation participates in the pathogenesis of PV. In current clinical practice, two different clinical approaches have been used to diagnose PV. One approach requires establishing the presence of absolute erythrocytosis by directly determining the red cell mass (RCM). A second approach utilizes a RCM-independent diagnostic algorithm based on the serum Epo level and bone marrow histology. Screening for JAK2 V617F can now be added to both diagnostic algorithms. However, it is very clear that some patients with classical PV lack the JAK2 V617F mutation, while some patients with other chronic myeloproliferative disorders such as idiopathic myelofibrosis (IMF) and essential thrombocytosis (ET) also express the JAK2 V617F mutation. Therefore, by necessity, any discussion of PV must take into consideration these companion myeloproliferative disorders, and since erythrocytosis is the single clinical feature that sets PV apart from IMF and ET, it is clear that the presence of the JAK2 V617F mutation cannot by itself establish a diagnosis of PV. Phlebotomy remains the mainstay of therapy for PV. In addition, both aspirin and cytoreductive therapy have been employed to control thrombocytosis and in the case of the latter, leukocytosis and extramedullary hematopoiesis as well. Despite recent progress in the field, several important issues remain controversial. In this review, we will present the areas of agreement, but also point out where the authors' personal viewpoints differ.