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At least 217 records · Page 12Linked to original sources
PubMed1997

[Anesthesia in two patients with essential thrombocythemia].

Case 1. The patient was a 69-year-old man with essential thrombocythemia (ET), who underwent urgent laparotomy. On admission he was dehydrated and the platelet count was more than 160 x 10(4).microliter-1, with hematocrit of 50%. Anesthesia was induced with ketamine i.v. and maintained with nitrous oxide and sevoflurane in oxygen. Postoperative care included the administration of gabexate mesilate (GM) which is an antiplatelet agent. Case 2. An 84-year-old woman with ET was diagnosed as gastric cancer and elective gastrectomy was scheduled. The platelet count was more than 100 x 10(4).microliter-1. The patient was anesthetized with nitrous oxide and oxygen supplemented with fentanyl and mepivacaine via epidural catheter. Intravenous infusion of GM was performed at a rate of 1 mg.kg-1.hr-1 during surgery. PF-4 and beta-TG were measured. These are platelet releasing factors. The level of PF-4 decreased to normal level during this procedure. In conclusions, it will be important to use GM during anesthesia in order to avoid the complications such as myocardial or pulmonary infarction caused by thrombocythemia.

Aged↗
PubMed1999

Treatment of essential thrombocythemia with anagrelide.

Essential thrombocythemia (ET), the most common of the chronic myeloproliferative disorders, is characterized by thrombotic and hemorrhagic complications. Thrombotic complications predominate, endangering especially the older population and those with prior history of thrombotic episodes. However, because the life expectancy of ET patients is generally of normal length, caution must be exercised in treating these patients, and the complications of treatment must be weighed against the complications of the disease. Historically, most drugs used in the treatment of ET, such as alkylating agents and radiophosphorus, were carcinogenic themselves. Even hydroxyurea has recently come under investigation for its long-term mutagenicity. The newest drug, anagrelide, approved in March 1997 specifically for ET, appears to be safe and well tolerated.

Humans↗
PubMed1991

Essential thrombocythemia: a hypercoagulable state.

Essential thrombocythemia is an entity characterized by clonal proliferation of megakaryocytes and thrombocytosis. We have analyzed the presenting manifestation of 13 patients with Essential Thrombocythemia diagnosed in the last three years. The major findings include the frequent presence of symptomatology of a hypercoagulable state with prompt improvement of these symptoms once the thrombocytosis is controlled. Constitutional symptoms, organomegaly, modest Leukocytosis and eosinophilia were also often seen. No catastrophic events were detected with a mean follow up period of 17.5 months.

Adolescent↗
PubMed1988

Controlled and uncontrolled thrombocytosis. Its clinical role in essential thrombocythemia.

Only two of 19 patients with spontaneously evolving essential thrombocythemia remained asymptomatic in a 421 patient-month observation. The rest of the patients showed hemorrhagic diathesis (four patients), nonspecific neurological semiology (two patients), and occlusive vascular illness in cerebral, myocardic, arterial, and often multiple locations (total, 12 patients). Peripheral neuropathy was found in five of 10 patients studied. In this series the incidence of cerebral ischemia in the uncontrolled condition was 180 times higher than the epidemiologic expectancy in a population not affected by the disorder. Of 35 ischemic attacks, 22 occurred when the platelet count was more than than 1000 X 10(9)/l, 13 when the count ranged from 650 to 990 X 10(9)/l, and none occurred at counts of less than 650 X 10(9)/l. In contrast, therapeutic control of the thrombocytosis caused all complications to disappear. These findings point out the danger of the natural course of the illness and justify active therapy. At the same time they call into question some of the most commonly used criteria in the diagnosis of essential thrombocythemia.

Adult↗
PubMed1998

Surgery for cholecystocholedocholithiasis in a patient with asymptomatic essential thrombocythemia: report of a case.

Essential thrombocythemia (ET) is a myeloproliferative disorder characterized by a remarkable increase in the platelet count and various clinical symptoms. The perioperative management of patients with ET has yet to be determined, especially when there are no clinical symptoms. We report herein the case of a woman with gallstones whose preoperative hematological data showed remarkable thrombocythemia, but her coagulation studies were normal. The Philadelphia chromosome was negative and bone marrow cytology showed a marked increase in megakaryocytes. Surgery was performed under a diagnosis of cholelithiasis with ET. Considering her severe thrombocythemia and obesity, sufficient heparin was administered to prevent deep vein thrombosis; however, this precipitated postoperative bleeding, necessitating a reoperation. A functional abnormality of the patient's platelets was suspected, and the aggregation by adenosine diphosphate was subsequently found to be significantly inhibited. As patients having ET with no symptoms might have depressed platelet aggregability despite remarkable thrombocythemia, when abdominal surgery is performed, prophylactic therapy for deep vein thrombosis should be avoided. Hence, the preoperative aggregation study of platelets might offer useful information about whether postoperative antithrombotic therapy is indicated.

Anticoagulants↗
PubMed1989

[Histomorphologic findings of the bone marrow in chronic myeloproliferative diseases].

Our survey on the histology of the bone marrow in chronic myeloproliferative disorders (CMPD) basically gives a description of the relevant lesions of the different subtypes (i.e. chronic myeloid leukemia, primary osteomyelofibrosis, polycythemia vera rubra, and primary thrombocythemia) in correlation with important clinical findings, such as the myelofibrosis/sclerosis syndrome, blast crisis, and prognosis. In a schematic presentation, we assigned the main features of hematopoiesis, interstitial space, and bone tissue to the various subtypes of CMPD, taking into consideration, as well, the evolution of histomorphological lesions in the course of the disease process, which could be determined by means of sequential biopsies. Particularly in the early hyperplastic stages of primary osteomyelofibrosis and in primary (essential) thrombocythemia, we observed a considerable elevation of the platelet count, possibly leading to thrombosis and hemorrhage.

Bone Marrow↗
PubMed1999

Cost-effectiveness model of a phase II clinical trial of a new pharmaceutical for essential thrombocythemia: is it helpful to policy makers?

Essential thrombocythemia (ET) is a rare, chronic myeloproliferative disorder of unknown origin characterized by thrombocytosis, excessive megakaryocytes, hemorrhages, and thrombotic complications. Because of the high costs of care for persons with rare diseases, policymakers are concerned with both clinical effectiveness and cost-effectiveness of new treatments. Although the clinical efficacy of all new pharmaceutical agents for rare diseases is evaluated extensively in clinical trial settings before approval by the Food and Drug Administration (FDA), comparative phase III trials of a new agent with its major competitor are sometimes not possible to carry out, and estimates of cost-effectiveness are therefore difficult to obtain. We describe methodologic issues associated with the development of economic models of new pharmaceutical agents for rare diseases and illustrate these issues with an analysis of a new therapy for ET. Anagrelide is a newly approved platelet aggregation inhibitor that can be used as primary therapy for ET. The agent reduces platelet counts by 50% in more than 70% of ET patients. Economic models suggest that, over the first year of anagrelide therapy, monthly costs for therapy and complications decreased from $775 to $490, the effectiveness improved to 98%, and the cost-effectiveness improved to $1,505 per major complication (gastrointestinal bleed, transient ischemic attack or stroke, or preinfarction angina or myocardial infarction) prevented. Sensitivity analyses indicate that, after the first 3 months of treatment, total costs of anagrelide treatment were in the range of $1,505 to $1,615 per major complication prevented. To make well-informed therapeutic decisions, policymakers and physicians require head-to-head studies of a new pharmaceutical agent with its major competitor. However, economic models can be used to derive estimates of cost-effectiveness of new pharmaceutical agents when such data are lacking. The interpretation of these models raises general issues related to the perspective of the investigator, study design, estimation of costs of care, rates of response, toxicity, survival, and the ability to generalize the results to other settings, as well as methodologic issues that are unique to rare diseases. If a comparative study found better therapeutic outcomes, then cost-effectiveness models would be of limited usefulness. Almost all physicians would use the drug with the better therapeutic profile.

Clinical Trials, Phase II as Topic↗
PubMed1997

The paradox of bleeding and thrombosis in thrombocythemia: is von Willebrand factor the link?

Thrombosis and bleeding, reflecting the extreme ends of hemostasis, are common complications in patients with thrombocythemia in its primary form or in association with polycythemia vera. The pathogenesis of these thrombohemorrhagic predispositions is not clearly understood. In the present study we describe the paradoxical and sequential occurrence of thrombotic and bleeding complications in six patients with thrombocythemia. Strikingly, in all patients some abnormality of plasma von Willebrand factor was detected. The potential role of von Willebrand factor in the pathogenesis of these hemostatic complications is discussed.

Aged↗