Survival and function of transfused platelets. Studies in two patients with congenital deficiencies of platelet membrane glycoproteins.

Platelets of patients suffering from Glanzmann's thrombasthenia (GT) and Bernard Soulier Syndrome (BSS) are defective in different membrane glycoproteins. Since these integrins can be identified by monoclonal antibodies, normal infused platelets could be distinguished from defective platelets and followed by using flow cytometry (FC). We studied this aspect in two recipients suffering, one from GT and the other one, who underwent splenectomy, from BSS. One hour after transfusion, normal platelets comprised 17% of the total platelet population in the patient with GT. Aggregation tests detected a measurable response to collagen (increase of 15% of transmittance). The presence of transfused platelets decreased progressively to 0.8% on day 4, which corresponded with a half-life of 2.6 days. Studies performed in the patient suffering from BSS found that 1 hour after transfusion, 53% of the platelet population corresponded to normal platelets. There was a progressive decay until day 6, which corresponded to a half-life of 4.6 days. Aggregation tests also detected a platelet response to ristocetin from 1 hour after transfusion (47% increase of transmittance) to day 3. FC is useful to measure platelet lifespan in these kinds of patients. We also report the first studies of platelet aggregation after platelet transfusion.

Tratamiento anticoagulante oral. Estudio coste/beneficio / Oral anticoagulation: cost/benefit study

El tratamiento anticoagulante oral (TAO) se aplica a más del 1% de la población y experimenta un crecimientosuperior al 10% anual. La demanda de recursos clínicos y analíticos que precisa el control de este tratamiento obliga adestinar importantes medios económicos y de logística sanitaria para su atención. De las múltiples estrategias paraafrontarlo (asistencia hospitalaria, atención primaria o autocontrol) deben establecerse estudios comparativos que reflejenno solo los costes de su actuación sino también sus resultados clínicos, medidos como mortalidad y la morbilidad delos episodios tromboticos y hemorrágicos ocurridos y evitados.En 4 unidades de anticoagulacion de grandes hospitales nacionales, que dan cobertura sanitaria a 1.641.914 habitantes,se hizo el seguimiento de 20.347 pacientes en TAO, durante el año 2003. Se registraron los episodios trombóticos ohemorrágicos aparecidos y se calcularon los mismos eventos que a tenor de sus patologías se deberían de haber producido.Las complicaciones tromboembolicas aparecidas fueron 299, que generaron 129 ingresos hospitalarios y ocurrieron11 exitus. Las complicaciones hemorrágicas graves generaron 181 ingresos hospitalarios y produjeron 20 exitus.Los costes del TAO en esta población atendida (medicación y su control clínico/analítico fueron estimados en 2.749.813 €.Los gastos sanitarios ocasionados (calculados según los GRD de las patologías) de las complicaciones clínicas aparecidasfueros estimados en 1.068.259 €.Las complicaciones evitadas fueron calculadas en más de 100 exitus y en 1.044 accidentes vasculares cerebrales y583 recidivas tromboticas con unos costes estimativos, sólo en la fase aguda intrahospitalaria, superiores a los 5.000.000 €

More than 1% of the population are on oral anticoagulant treatment (OAT), a figure which is growing by over 10%annually.The demand for the clinical and analytical services necessary for monitoring this treatment requires the assignmentof significant economical and healthcare logistic resources. Comparative studies of the multiple control strategies(attending hospital, primary care or self-monitoring) should be set up, and should reflect not only the costs of their performancebut also their clinical results, measures such as mortality and morbidity of thrombotic and haemorrhagic episodesthat have occurred and been avoided.During 2003, 20,347 patients on OAT were monitored in 4 anticoagulation units of large national hospitals providinghealthcare cover to 1,641,914 inhabitants. Thrombotic or haemorrhagic episodes were recorded and the same eventsthat should have occurred, according to their pathologies, were calculated.Two hundred and ninety-nine thromboembolic complications occurred which led to 129 hospital admissions and therewere 11 deaths. Serious haemorrhagic complications resulted in 181 hospital admissions and caused 20 deaths.The costs of OAT in the population attended (medication and their clinical/analytical monitoring) were estimated at€2,749,813. The healthcare costs (calculated according to the DRG of the pathologies) of the clinical complicationswhich occurred were estimated at €1,068,259.The complications avoided were calculated at more than 100 deaths, 1,044 cerebrovascular accidents and 583thrombotic recurrences with estimated costs, in the acute intrahospital phase only, of greater than €5,000,000

[Morbidity and mortality in patients treated with oral anticoagulants]. / Morbilidad y mortalidad en pacientes con tratamiento anticoagulante oral.

INTRODUCTION AND OBJECTIVES: The number of patients receiving oral anticoagulant therapy has increased markedly in recent years, with the consequence that monitoring must be decentralized. The aim of this study was to provide reference values for the quality of care in patients receiving oral anticoagulants at large specialized Spanish centers for use in future comparative analyses. METHODS: The records of 20,347 outpatients who were receiving oral anticoagulants between January and December 2003 at four large Spanish centers were assessed. Databases at the four hospitals were searched for severe adverse events. RESULTS: In total, 211,987 regular check-ups were carried out, 72.7% of which gave international normalized ratios (INRs) within the range 2-4. Overall, 2369 hemorrhagic events were observed, 190 (8%) of which were severe, with 20 deaths (0.1 per 100 patient-years). In addition, there were 299 thromboembolic events, with 11 deaths (0.05 per 100 patient-years). The frequency of these events was greater in patients with a cardiac prosthesis, who required more intense anticoagulation. The incidence of death with different diagnoses was also greater in anticoagulated patients with a cardiac prosthesis, and the highest probability of death (1 in 3) was associated with episodes of cerebral hemorrhage. The incidence of hemorrhage increased as the INR increased. In contrast, thrombotic events occurred principally when the INR was below 2, and were not observed with INRs over 6. CONCLUSIONS: The incidence of adverse events in patients receiving oral anticoagulant therapy at large Spanish centers was similar to that observed in other European countries.

Morbilidad y mortalidad en pacientes con tratamiento anticoagulante oral / Morbidity and mortality in patients treated with oral anticoagulants

Introducción y objetivos. El número de pacientes en tratamiento anticoagulante oral (TAO) ha crecido notablemente en los últimos años y ha demandado un proceso de descentralización de los controles. El objetivo de este estudio es tener una referencia de los índices de calidad de la población en TAO seguida en grandes unidades especializadas de España que permita un análisis comparativo futuro. Métodos. Se valoraron desde enero a diciembre de 2003 las fichas de los 20.347 pacientes en TAO controlados en 4 grandes unidades del país. Se buscó efectos adversos severos en los ficheros informatizados de los 4 hospitales. Resultados. Se realizaron 211.987 controles, y el 72,7% está dentro de un rango de 2-4. Se detectaron en total 2.369 eventos hemorrágicos, 190 (8%) graves, con 20 fallecimientos (0,1/100 pacientes/año). Hubo 299 episodios tromboembólicos con 11 fallecimientos (0,05/100 pacientes/año). La frecuencia de estos eventos fue mayor en aquellos enfermos con prótesis cardiacas, que precisaban una mayor intensidad de anticoagulación. La incidencia de fallecimientos por diagnósticos fue también mayor en pacientes anticoagulados por prótesis cardiacas y la mayor probabilidad de muerte (1 de cada 3 pacientes) se asoció a episodios de hemorragia cerebral. La incidencia de hemorragia se incrementó en función de la prolongación del INR, mientras que los eventos trombóticos aparecieron especialmente con INR < 2, y no se detectaron con INR > 6. Conclusiones. La incidencia de efectos adversos que afectan a los pacientes en TAO controlados en grandes unidades del país es similar a las reconocidas en otros países occidentales (AU)

Introduction and objectives. The number of patients receiving oral anticoagulant therapy has increased markedly in recent years, with the consequence that monitoring must be decentralized. The aim of this study was to provide reference values for the quality of care in patients receiving oral anticoagulants at large specialized Spanish centers for use in future comparative analyses. Methods. The records of 20,347 outpatients who were receiving oral anticoagulants between January and December 2003 at four large Spanish centers were assessed. Databases at the four hospitals were searched for severe adverse events. Results. In total, 211,987 regular check-ups were carried out, 72.7% of which gave international normalized ratios (INRs) within the range 2­4. Overall, 2369 hemorrhagic events were observed, 190 (8%) of which were severe, with 20 deaths (0.1 per 100 patient­years). In addition, there were 299 thromboembolic events, with 11 deaths (0.05 per 100 patient­years). The frequency of these events was greater in patients with a cardiac prosthesis, who required more intense anticoagulation. The incidence of death with different diagnoses was also greater in anticoagulated patients with a cardiac prosthesis, and the highest probability of death (1 in 3) was associated with episodes of cerebral hemorrhage. The incidence of hemorrhage increased as the INR increased. In contrast, thrombotic events occurred principally when the INR was below 2, and were not observed with INRs over 6. Conclusions. The incidence of adverse events in patients receiving oral anticoagulant therapy at large Spanish centers was similar to that observed in other European countries (AU)

Emergence of chronic myelogenous leukemia in a patient with primary thrombocythemia and absence of BCR/ABL rearrangement.

A 65-year-old woman presented with clinical features of primary thrombocythemia (PT), and absence of the BCR/ABL fusion gene. She responded to hydroxyurea treatment, although after 1 year she required progressive increases in the dose. Six years later, she maintained a high platelet count despite hydroxyurea at 2 g/day and treatment was changed to anagrelide. After 3 weeks, both platelet and leukocyte counts increased. A karyotype study detected the Philadelphia chromosome in all of the 24 metaphases studied. Fluorescent in situ hybridization (FISH) analysis revealed the BCR/ABL rearrangement. The patient was treated with imatinib mesylate and achieved a normal platelet and leukocyte count in 3 weeks. Patients presenting clinical features of PT expressing the Ph chromosome or the BCR/ABL fusion gene have been well documented but, to our knowledge, this is the first report of evolution from typical PT to chronic myeloid leukemia.

Lactate production by thrombin-activated platelets of patients with primary thrombocythemia.

INTRODUCTION: Platelet activation needs a high energy demand which is supplied by the degradation of glucose into lactate. Platelet response to agonists in patients with primary thrombocythemia is defective. We studied the production of lactate by the platelets of patients with this disease and defective platelet aggregation. MATERIAL AND METHODS: Ten patients suffering from primary thrombocythemia and ten controls were included in this study. The lactate generation was measured in resting and thrombin activated platelets in absence or presence of glucose. RESULTS: Resting platelets incubated for 30 min in phosphate-buffered saline (PBS) generated the same amount of lactate in patients (44.6+/-21.6 micromol/10(11) cells) and controls (41.0+/-17.3 micromol/10(11) cells). Addition of glucose led to similar increases in lactate formation by platelets in patients (82.2+/-26.4 micromol/10(11) cells) and controls (88.1+/-34.5 micromol/10(11) cells). The addition of thrombin in absence of glucose did not modify the lactate formation respective to PBS. Finally, the incubation of platelets with both glucose and thrombin caused further increases in the generation of lactate in both groups, patients (236.9+/-83.9 micromol/10(11) cells) and controls (228.6+/-63.5 micromol/10(11) cells) without differences between them. The production of lactate in both groups was also similar when platelets were incubated for 10 min or 20 min with both thrombin and glucose. However at 5 min, platelets of patients generated more lactate (97.8+/-23.7 micromol/10(11) cells) than controls (66.5+/-38.7 micromol/10(11) cells, p<0.05). CONCLUSIONS: These results suggest that thrombin is able to induce an initial hyperactivity of those pathways involved in the platelet energy production of patients with primary thrombocythemia.

Platelet dysfunction in primary thrombocythemia using the platelet function analyzer, PFA-100.

We measured platelet function by standard aggregometric tests and by the PFA-100 (Dade Behring, Newark, DE) in samples from 55 patients with primary thrombocythemia (PT) and 26 healthy volunteers. Platelet function was evaluated in platelet-rich plasma by aggregation tests. PFA-100 studies (closure time) were performed in citrated whole blood using collagen-adenosine diphosphate (ADP) and collagen-epinephrine cartridges. Plasma levels of von Willebrand factor (vWF) also were measured. The mean +/- SD closure time for patients vs volunteers for the collagen-epinephrine cartridge was prolonged (210.8 +/- 62.2 vs 118.1 +/- 19.6 seconds; P < .001); results were abnormal for 38 patients (69%). Results with the collagen-ADP cartridge also were abnormal in patients (134.3 +/- 58.4 seconds) vs volunteers (87.3 +/- 15.6 seconds; P < .001); closure time was prolonged in 23 patients (42%). A decreased response to epinephrine (38.4% +/- 34.2% vs 82.5% +/- 10.3%; P < .001), the main defect detected by platelet aggregation tests, affected 32 patients (58%). Platelet response to collagen also was abnormal (52.0% +/- 34.6% vs 86.0% +/- 10.1%; P < .01) but affected only 21 patients (38%). vWF levels for patients were normal. The results seem to confirm that platelet function in patients with PT is abnormal and show that platelet function can be assessed by an easy, reproducible, and sensitive method, the PFA-100. Closure time usually was prolonged; this feature could be applied in the diagnosis of PT.

Aging and oral anticoagulant therapy using acenocoumarol.

We evaluated the influence of aging, gender and indications of anticoagulant therapy on acenocoumarol requirements in 1845 patients from 30 to 99 years old receiving acenocoumarol therapy who were monitored in our hospital outpatient anticoagulation clinic from March 1993 through September 1999. The patients were stratified in seven age groups, comprising older than 80 years and the five decades between 30 years and 80 years. We found a progressive decrease in the acenocoumarol requirements from 30 years to 80 years (rho=-0.98), which was estimated as 2.7 mg/week per decade (11.5% per decade). This decrease was not the consequence of a different range of anticoagulation or differences in body weight. We did not find correlation between the decrease of acenocoumarol requirements and different biochemical parameters including, creatinine, calcium and alanine aminotransferase. We detected a progressive decrease in levels of serum total proteins but changes in this parameter did not correlate with the amount of acenocoumarol requirements. The dose of acenocoumarol (mg/week per patient) of those patients suffering from venous thromboembolism were higher than the remainder of the patients (18.4 +/- 9.3 versus 14.5 +/- 7.8, P <0.0001). This finding was also detected, after stratifying the patients by decades, from 60 years to 80 years. In conclusion, requirements of acenocoumarol decrease with aging; this decrease represents an important amount from 30 years to 80 years and it should be kept in mind to choose the initial dose of acenocoumarol. Patients with venous thromboembolism required a higher dose of acenocoumarol.

Phospholipase A2 activity in platelets of patients with uremia.

Platelets of patients with uremia develop a defective platelet function and have a decreased production of thromboxane B2 (TxB2). Activated platelets generate thromboxane from free arachidonate that is previously released from the membrane phospholipids (PLs) by phospholipases. Phospholipase A2 (PLA2) release up to 70% of the arachidonate in normal platelets, and to date, the activity of this enzyme in uremia is unknown. This work studied the PLA2 activity in the platelets of nine uremic patients and nine healthy volunteers. Washed platelets were labelled with [(14)C]arachidonic acid and activated with calcium ionophore A-23187 (4 microgr/ml). Lipids were resolved by TLC and identified by autoradiography. The distribution of [(14)C]arachidonic acid in the five major platelet phospholipids was found to be normal. Uremic platelets released more radioactivity than normal platelets (19.0 +/- 5.2% versus 11.3 +/- 1.6%, P = 0.001). The production of both, radioactive thromboxane B2 and hydroxyheptadecatrienoic acid was normal (2.6 +/- 1.2% and 3.5 +/- 1.6% of total radioactivity respectively), but the formation of the lipoxygenase metabolite hydroxyeicosatetraenoic acid was increased with respect to the controls (12.9 +/- 4.6% vs 7.0 +/- 1.3% of total radioactivity, P = 0002). In conclusion, platelets of patients with uremia have an increased activity of phospholipase A2 and produce increased amounts of hydroxyeicosatetraenoic acid, an inhibitor of the platelet function.