Recomendaciones de prevención y tratamiento de tromboembolismo venoso en infección por SARS-CoV-2 / Recommendations for the prevention and treatment of venous thromboembolism in SARS-CoV-2 infection

Coronavirus disease (Covid-19) is characterized by an intense inflammatory response and coagulopathy that is associated to a high incidence of thrombotic events with in situ thrombosis of the microcirculation of the lungs and other organs, which is the key event in the pathogenesis of the respiratory and multi-organ failure. These observations have led to to the use of heparin, which has anticoagulant, antiinflammatory and anti-viral properties, as the best agent to treat these patients. Clinical guidelines recommend the use of heparin thromboprophilaxis in these patients, although there is no agreement in the indication, dose and duration of thromboprophylaxis due to lack of randomized studies. (AU)

Tromboprofilaxis en pacientes médicos hospitalizados. ¿A todos por igual? / Thromboprophylaxis in hospitalized medical patients. Do all alike?

Venous thromboembolic disease is the leading preventable cause of hospital mortality. Up to 75 percent of these are in non - surgical patients. This is a large, heterogeneous group of patients; so to know the risk factors for deep venous thrombosis crucial to provide a correct prevention. This article reviewed the indications, contraindications and complications of thromboprophylaxis. Difficult cases in elderly, obese, chronic kidney disease, critical care and cirrhotic patients were reviewed. The purpose of this article is to support decision – making on dvt prevention in hospitalized medical patients...

Tromboprofilaxis farmacológica en pacientes oncológicos quirúrgicos en el Hospital Clínico de la Universidad de Chile / Pharmacological thromboprophylaxis in surgical oncology patients in Hospital Clínico Universidad de Chile

The aim of this study is to evaluate the use of thromboprophylaxis in surgical oncology patients in HCUCH in 2011. Method: Retrospective analysis of patients with cancer undergoing surgery in 2011. Was defined as adequate pharmacological thromboprophylaxis the correct dose, mechanical prophylaxis in case of drug contraindications and beginning on day 0 or 1. Results: 131 medical records were reviewed. Main neoplasms were colorectal (21.3 percent), prostate (12.9 percent), gallbladder (8.3 percent) and stomach (6.9 percent). Of the patients requiring pharmacologic thromboprophylaxis (n = 110) were rated as adequate 52 patients (47 percent), 47 inadequate (43 percent) and 11 absent (10 percent). The causes of inappropriate use of pharmacological thromboprophylaxis included 27 late onset (58 percent), 10 lower doses (21 percent), 3 late onset associated with lower dose (6 percent), 6 incomplete thromboprophylaxis (13 percent) and 1 dose increased (2 percent). Factors significantly associated with pharmacological thromboprophylaxis absent were: <40 years of age (p = 0.002), head and neck cancer (p < 0.001), and hospital stay <7 days (p < 0.001). Conclusions: The absence of pharmacological thromboprophylaxis is associated with lower absolute risk factors for VTE: Age less than 40 years old, head and neck cancer, hospital stay less than 7 days...

[Acquired hemophilia A treated with rituximab. Report of one case]. / Hemofilia adquirida tratada con anti CD20, un anticuerpo anti linfocito B.

We report a 54-year-old male presenting with a history or recurrent nose bleeds and ecchymoses. The coagulation study showed a prolonged partial thromboplastin time, a factor VIII of 8% and a high inhibitor titer (193 Bethesda units). A diagnosis of acquired hemophilia A was reached. The patient was initially treated with cyclophosphamide for seven months without response. Therefore rituximab in doses of 375 mglm²/week for four weeks was started. After starting treatment, the patient had a hematoma in the psoas muscle with a concomitant factor VIII of less than 5%, that was treated with local measures. Thereafter, a progressive reduction in inhibitor titers was observed, until its disappearance at five months of treatment. Factor VIII levels normalized and the patient has not experienced abnormal bleeding episodes. The patient remains in remission after 67 months of follow up. Rituximab, a chimeric monoclonal antibody against the protein CD 20 is an effective treatment in acquired hemophilia A.

Hemofilia adquirida tratada con anti CD20, un anticuerpo anti linfocito B / Acquired hemophilia a treated with rituximab. Report of one case

We report a 54-year-old male presenting with a history or recurrent nose bleeds and ecchymoses. The coagulation study showed a prolongedpartial thromboplastin time, a factor VIII of 8 percent and a high inhibitor titer (193 Bethesda units). A diagnosis of acquired hemophilia A was reached. The patient was initially treated with cyclophosphamide for seven months without response. Therefore rituximab in doses of 375 mglm²Iweek for four weeks was started. After starting treatment, the patient had a hematoma in the psoas muscle with a concomitantfactor VIII ofless than 5 percent, thatwas treated with local measures. Thereafter, aprogressive reduction in inhibitor titers was observed, until its disappearance atfive months of treatment. Factor VIII levéis normalized and the patient has not experienced abnormal bleeding episodes. The patient remains in remission after 67 months offollow up. Rituximab, a chimeric monoclonal antibody against theprotein CD 20 is an effective treatment in acquired hemophilia A.

Trombohematoma subcorionico masivo: una patología placentaria emergente / Massive subchorionic thrombohematoma

El trombohematoma subcoriónico es una extravasación de sangre localizada en la placa coriónica, entre amnios y corion. Es muy infrecuente, el diagnóstico no es común, tiene alto riesgo perinatal y no hay casos comunicados en nuestro medio. Se presentan 12 casos de sospecha diagnóstica antenatal, confirmada en el examen histopatológico placentario. Se describe y discute el cuadro clínico, las complicaciones maternas y perinatales, el diagnóstico ultrasónico, el manejo y los resultados obtenidos. En nueve casos se identifcó una fase latente con hematoma de tamaño estable, entre el inicio de los síntomas y el parto, que duró en promedio 7,3 semanas. En ocho casos la fase latente fue seguida por una fase activa con aumento del hematoma asociado al parto prematuro. Tres embarazadas presentaron patología médica compleja con una muerte materna. Seis casos hicieron anemia severa y tres patología miscelánea. Hubo ocho amenazas de parto prematuro con tocolisis, tres rotura prematura de membranas, una colestasis y una preeclampsia. Los partos fueron prematuros, dos de 36 y 33 semanas y diez menores a 32 semanas. Siete prematuros tuvieron peso inferior a 1000 gramos y seis hicieron restricción fetal grave, en percentil <5 de la curva de crecimiento. Hubo complicaciones neonatales relacionadas con prematurez, restricción y bajo peso, manejados con hospitalización prolongada con promedio de 74 días (rango: 6-298 días). Diez neonatos sobrevivieron; hubo un mortinato y un mortineonato. La sobrevida fue 83,3 por ciento y la mortalidad de 16,6 por ciento que se comparan favorablemente con las cifras comunicadas.

Subchorial thrombohaematoma is caused by blood extravasations in the corionic plate, between amnion and chorion. It is a rare pathologic entity, that carries a high perinatal risk, which has not being published in our country up to now. We report 12 cases in which the diagnosis was suspected before birth, and confirmed in the placentary pathological examination. We describe the clinical presentation, fetal and maternal risks, ultrasonographic findings, treatment and clinical outcomes. In 9 patients a latent phase was identified with a stable size hematoma, which had a mean duration of 7.3 weeks. In 8 cases the latent phase was followed by an active phase, with increasing size of the hematoma associated with preterm labour. Three pregnant women had severe complications which caused one maternal death. Six had severe anemia and other three had minor complications. Eight had preterm labor symptoms which required tocolysis. Three had prelabour rupture of membranes, one cholestasis disease and preeclampsia. Preterm labours were at 36, 33 and other ten before 32 weeks of gestation. Seven preterm newborns weight less than 1000 grams and six had severe fetal restriction (p<5). Newborn complications were related with prematurity, requiring prolonged hospitalization (mean 74 days, range 6-298 days). Ten newborns survived. There were 1 still birth and 1 dead newborn. Survival rate was 83.3 percent and 16.6 percent mortality, better rates than previously published.

[Genetic markers as prognostic factors in multiple myeloma]. / La genética como factor pronóstico y terapéutico en el mieloma múltiple.

The search for prognostic factors in multiple myeloma has identified the genetic profile of the tumor as the main determinant of patient survival and response to treatment. There is an association between a dismal prognosis and the presence of t(4:14) translocations or 17p deletion, determined by fluorescent in situ hybridization (FISH) or the detection of chromosome 13 deletion using conventional cytogenetic techniques. These alterations define a subpopulation that comprises 25% of patients with a bad prognosis even if they are treated with high dose chemotherapy These patients should be early derived to more specific therapies. In the other hand, the other 75% of patients without a genetic risk factor, have a higher probability of success with conventional treatment.

La genética como factor pronóstico y terapéutico en el mieloma múltiple: [revisión] / Genetic markers as prognostic factors in multiple myeloma: [revision]

The search for prognostic factors in multiple myeloma has identified the genetic profile of the tumor as the main determinant of patient survival and response to treatment. There is an association between a dismal prognosis and the presence of t(4:14) translocations or 17p deletion, determined by fluorescent in situ hybridization (FISH) or the detection of chromosome 13 deletion using conventional cytogenetic techniques. These alterations define a subpopulation that comprises 25% of patients with a bad prognosis even if they are treated with high dose chemotherapy. These patients should be early derived to more specific therapies. In the other hand, the other 75% of patients without a genetic risk factor, have a higher probability of success with conventional treatment.

Frecuencia de tromboembolismo venoso en pacientes hospitalizados con cáncer: factores de riesgo y eficacia de la tromboprofilaxis farmacológica / Frequency of venous thromboembolism among hospitalized patients with cancer

Background: Hospitalized patients with cancer have a high risk of venous thromboembolism (VTE). Aim: To study the frequency of VTE and its risk factors in hospitalized patients with cancer. Material and methods: Retrospective analysis of clinical records of patients with cancer, hospitalized at a university hospital between 2002 and 2004. Patients with the diagnosis of VTE at admission or using anticoagulants, were excluded from the analysis. Results: The medical records of 366 patients were reviewed. Fifty three percent had a digestive cáncer, 19 percent lung cáncer, 10 percent breast cancer and 18 percent had a tumor of other origin. In 77 percent, the tumor was in an advanced stage. The most common admission diagnoses were pneumonía, vomiting and dehydration, gastrointestinal bleeding and urinary infection. In 125 patients (34 percent) pharmacological thrombo-prophylaxis was not used and 242 (66 percent) received regular or low molecular weight heparin. VTE was detected in 11 patients (3 percent) and was significantly more common among patients not receiving thrombo prophylaxis compared to those receiving heparin (6.4 percent and 1.2 percent, respectively p =0.014). Factors associated to VTE were a history ofprevious VTE with an odds ratio (OR) of 12.9 (p <0.01), obesity with an OR of 13.3 (p <0.01), recent chemotherapy with an OR of 6.9 (p =0.01). The use of pharmacological thromboprophylaxis had an OR of 0.24 (p =0.05). Conclusions: Three percent of patients in this series had VTE during the hospitalization. Pharmacological thrombo-prophylaxis significantly reduced the risk of VTE.

[Prognostic value of the new international staging system in multiple myeloma. Comparison with Durie-Salmon staging system]. / Valor pronóstico del nuevo sistema de etapificación internacional en mieloma múltiple: Comparación con el sistema de Durie-Salmon.

BACKGROUND: Since 1975, the Durie-Salmon staging system (D&S) has been a widely accepted prognostic classification of multiple myeloma (MM) patients. Recently, the new International Staging System (ISS) was developed using only the values of albumin and beta2-microglobulin. AIM: To compare survival of patients with MM treated in six medical centers in Chile according to the D&S system and the new ISS. MATERIAL AND METHODS: Retrospective analysis of demographic information, clinical features and survival rate of patients treated between 1998 and 2002, and grouped according to both systems. RESULTS: Information of 81 patients aged 38 to 90 years (43 women) was retrieved. According D&S system 11% were in stage I 12% in stage II and 73% in stage III According to ISS, 34% were in stage I 35% in stage II and 31% in stage III Median of survival of all patients was 32 months. Both staging systems had a prognostic value. However, median survival for the three stages of the ISS system was significantly different (67, 29 and 14 months in stages III and III, respectively, p =0.02). Patients in advanced stages II and III of the ISS, had a higher frequency of anemia, hypercalcemia, renal failure and hypoalbuminemia. In stages II and III of ISS the presence of renal failure was associated with a non significantly different lower survival. CONCLUSIONS: The ISS is a simple and effective grouping method for patients with MM, that predicts survival. The presence of renal insufficiency might identify a subgroup of patients included in stages II and III of ISS with a higher mortality.

Valor pronóstico del nuevo sistema de etapificación internacional en mieloma múltiple: Comparación con el sistema de Durie-Salmon / Prognostic value of the new international staging system in multiple myeloma: Comparison with Durie-Salmon staging system

Background: Since 1975, the Durie-Salmon staging system (D&S) has been a widely accepted prognostic classification of multiple myeloma (MM) patients. Recently, the new International Staging System (ISS) was developed using only the values of albumin and betaZ-microglobulin. Aim: To compare survival of patients with MM treated in six medical centers in Chile according to the D&S system and the new ISS. Material and methods: Retrospective analysis of demographic information, clinical features and survival rate of patients treated between 1998 and 2002, and grouped according to both systems. Results: Information of 81 patients aged 38 to 90 years (43 women) was retrieved. According D&S system 11 percent were in stage I 12 percent in stage II and 73 percent in stage III According to ISS, 34 percent were in stage I 35 percent in stage II and 31 percent in stage III Median of survival of all patients was 32 months. Both staging systems had a prognostic value. However, median survival for the three stages of the ISS system was significantly different (67, 29 and 14 months in stages III and III, respectively, p =0.02). Patients in advanced stages II and III of the ISS, had a higher frequency of anemia, hypercalcemia, renal failure and hypoalbuminemia. In stages II and III of ISS the presence of renal failure was associated with a non significantly different lower survival. Conclusions: The ISS is a simple and effective grouping method for patients with MM, that predicts survival. The presence of renal insufficiency might identify a subgroup of patients included in stages II and III of ISS with a higher mortality.

[Clinical features and survival of Chilean patients with multiple myeloma]. / Mieloma múltiple en Chile: Características clínicas y sobrevida.

BACKGROUND: Mortality rate records are the only data available in Chile about the prognosis of patients with multiple myeloma (MM). AIM: To characterize clinical features, survival rate and factors related to mortality in cases with MM treated in six large medical centers in Chile. MATERIAL AND METHOD: Retrospective analysis of demographic data, clinical features and survival rate records of patients with MM, collected between 1998 and 2002. Survival curves were generated and a multivariate analysis of factors associated to early mortality was carried out. RESULTS: Data from 245 patients aged 38 to 95 years (129 women) was collected. Fifty two percent had an IgG myeloma, 25% had and IgA and 6.1% had light chains myeloma. According to Durie and Salmon staging system, 8,2% were in Stage 112.6% in Stage II, 60.5% in Stage III and in 18.8% the information about staging was not available. Fifty percent had an hemoglobin level below 10 g/dL, 30% had a serum creatinine over 2 mg/dL and 28% had a serum calcium level over 10.5 mg/dL. Median survival was 33 months. Twenty percent of patients died within the first six months after diagnosis (early mortality). Predictive factors for early mortality were male sex, thrombocytopenia, anemia, renal failure, hypercalcemia, a beta2-microglobulin >5.5 mg/L and a serum albumin level <3.5 g/dL. There was a correlation between the number of bad prognosis factors present and the probability of early mortality. CONCLUSIONS: This group of Chilean patients with MM presented a short survival time, and 20% died within the first six months after diagnosis. More than a half of cases were diagnosed at an advanced stage (Durie and Salmon Stage III). Several factors were associated to early mortality, two of which (beta 2-microglobulin and serum albumin), are included in the new International Staging System for MM.

Mieloma múltiple en Chile: características clínicas y sobrevida / Clinical features and survival of Chilean patients with multiple myeloma

Background: Mortality rate records are the only data available in Chile about the prognosis of patients with multiple myeloma (MM). Aim To characterize clinical features, survival rate and factors related to mortality in cases with MM treated in six large medical centers in Chile. Material and Method: Retrospective analysis of demographic data, clinical features and survival rate records of patients with MM, collected between 1998 and 2002. Survival curves were generated and a multivariate analysis of factors associated to early mortality was carried out. Results: Data from 245patients aged 38 to 95years (129 women) was collected. Fifty two percent had an IgG myeloma, 25 percent had and IgA and 6.1 percent had light chains myeloma. According to Durie and Salmon staging system, 8,2 percent were in Stage 112.6 percent in Stage II, 60.5 percent in Stage III and in 18.8 percent the information about staging was not available. Fifty percent had an hemoglobin level below 10 g/dL, 30 percent had a serum creatinine over 2 mg/dL and 28 percent had a serum calcium level over 10.5 mg/dL. Median survival was 33 months. Twenty percent of patients died within the first six months after diagnosis (early mortality). Predictive factors for early mortality were male sex, thrombocytopenia, anemia, renal failure, hypercalcemia, a beta2-microglobulin >5.5 mg/L and a serum albumin level <3.5 g/dL. There was a correlation between the number of bad prognosis factors present and the probability of early mortality. Conclusions: This group of Chilean patients with MM presented a short survival time, and 20 percent died within the first six months after diagnosis. More than a half of cases were diagnosed at an advanced stage (Durie and Salmon Stage III). Several factors were associated to early mortality, two of which (beta 2-microglobulin and serum albumin), are included in the new International Staging System for MM.

Nuevos conceptos de mieloma múltiple / New concepts in multiple myeloma

El Mieloma Múltiple (MM) es una enfermedad caracterizada por una proliferación clonal de células plasmáticas y la presencia de una paraproteína en el suero y/u orina. La gamopatía monoclonal de significado indeterminado (GMSI) se caracteriza por la presencia de una proteína monoclonal < 3 g/dl y una plasmocitosis en la médula ósea menor del 10 por ciento. GMSI es más frecuente que el MM (prevalencia 3 por ciento en personas mayores de 70 años) y tiene un riesgo de progresión a MM de 1 por ciento por año. Los criterios diagnóstico de MM han sido recientemente actualizados por el International Myeloma Working Group. La clasificación pronóstica de Durie y Salmon (1975), se está reemplazando por el sistema de etapificación Internacional (ISS) que ha sido validado en más de 10.000 pacientes y utiliza 2 parámetros de laboratorio : B2 microglobulina y el nivel de albúmina sérica. Factores favorables en el pronóstico de MM son: B2 microglobulina < 2.5 mg/L, proteína C reactiva < 4.0 mg/dl, índice de marcación de células plasmáticas < 1 por ciento y ausencia de defectos del cromosoma 13. El MM es una enfermedad incurable y el tratamiento está indicado en los casos sintomáticos. En primer lugar debe plantearse si es candidato o no al transplante de médula ósea autólogo (TMO). El TMO autólogo doble prolonga la sobrevida global y tiempo libre de enfermedad, si se compara con el TMO único, especialmente para los que no entraron en remisión después del primer transplante. En aquellos pacientes que no son candidatos al TMO y de mayor edad, la indicación sigue siendo Melfalán – Prednisona. Recientes estudios demuestran mayores índices de remisión total y parcial con la combinación de Melfalán, Prednisona y Talidomida. Dentro del tratamiento es también importante la terapia de sostén ( bifosfonatos, eritropoyetina).

Multiple Myeloma (MM) is a disease characterized by a clonal proliferation of plasmatic cells and the presence of a monoclonal protein in the serum or urine. Monoclonal gammopathy of undetermined significance (MGUS) is characterized by the presence of a monoclonal protein <3 g/dl and bone marrow plasma cells <10 percent. MGUS is more frequent than MM (3 percent in >70 year-old) and has a risk of progression to MM of 1 percent per year. The diagnostic criteria of MM have been recently updated by the International Myeloma Working Group. The Durie-Salmon staging system (1975) is being replaced by the International Staging System (ISS) that has been proved in more than 10.000 patients and uses 2 laboratory parameters: B2 microglobulin and albumin. Positive prognostic factors in MM are: B2 microglobulin <2.5 mg/L, protein C reactive <4.0 mg/dl, Labeling Index of plasmatic cells <1 percent and absence of deletion of chromosome 13. MM is an incurable disease and its treatment is indicated in the symptomatic patients. First we must determine if the patient is a candidate of autologous bone marrow transplantation (BMT). Tandem autologous BMT prolongs global survival and event-free survival time, if it is compared with single BMT, especially for those who did not enter complete remission after first transplant. In those patients who are not candidates for autologous BMT, the indication continues being Melphalan - Prednisone. Recent studies demonstrate better response with the combination of Melphalan, Prednisone and Thalidomida. Supportive care is also important (biphosphonates, erythropoietin).

Dirección de las mutaciones factor V Leiden y protrombina G20210A en pacientes con trombosis venosa / Direction of the mutations factor V Leiden and Prothrombin G20210A in patients with venous thrombosis

El tromboembolismo venoso es una condición patológica de origen multifactorial, incluyendo causas adquiridas o genéticas. De estas últimas, las mutaciones puntuales factor V Leiden y Protrombina G20210A representan etiologías más frecuentes de trombosis hereditaria. Para el diagnóstico de estos efectos genéticos en pacientes con trombosis venosa, se realizan las técnicas de biología molecular de reacción en cadena de la polimerasa y polimorfismo del tamaño de los fragmentos de restricción. Desde febrero del 2001hasta diciembre de 2005 se realizaron 565 exámenes para la detección del factor V Leiden, encontrándose un 6,19 por ciento de prevalencia (35 pacientes). Esta cifra contrasta con algunos estudios y esta en concordancia con otros. En el mismo periodo se realizaron 557 exámenes para la detección de Protrombina G20210A, encontrándose un 6,1 por ciento de prevalencia (34 pacientes), valor que es muy similar a la mayoría de las series clínicas descritas.

Venous thromboembolism is a pathological condition of multifactorial origin, including acquired and genetic causes. The point mutation factor V Leiden and Prothrombin G2021OA are the most frequent etiologies of hereditary thrombosis. To diagnose these genetic defects in patients with venous thrombosis, the molecular biological technique of polymerase chain reaction – restriction fragment length polymorphism (PCR-RFLP) is used. In this study, 565 exams for the detection of factor V Leiden were carried out from February, 2001 through December, 2005, finding a prevalence of 6.19 percent (35 patients). This rate contradicts some studies and agrees with others. In the same period, 557 exams for the detection of prothrombin G2021OA were performed, finding a prevalence of 6.1 percent (34 patients), a very similar value to the prevalence reported in the majority of the published clinical series.

Síndrome antifosfolípidos y trombocitopenia materna en gemelar bicoriónico con restricción fetal grave / Antiphospholipid syndrome and maternal thrombocytopenia in dichorionic twins with severe fetal growth restriction

Se presenta un caso clínico de síndrome antifosfolípidos con antecedente de mortinato y tratamiento anticoagulante prolongado. En la segunda gestación (gemelar bicoriónico) desarrolla una restricción fetal precoz selectiva en un gemelo, seguido de detención definitiva de su crecimiento en semana 25. Luego del tratamiento de una trombocitopenia materna intercurrente se decidió la interrupción del embarazo en semana 28 por operación cesárea. Ambos gemelos de 860 y 406 gramos sobrevivieron en buenas condiciones al período neonatal. Se discuten los mecanismos etiopatogénicos y aspectos singulares observados en la adaptación circulatoria del gemelo B.

Autotrasplante (AT) de progenitores hematopoyéticos en mieloma múltiple: Experiencia clínica / Autologous transplant (AT) with peripheral-blood stem-cell rescue for multiple myeloma: A clinical experience

Background:Multiple myeloma is rarely curable. Advances in high dose chemotherapy and stem cell transplantation have improved overall survival and event-free disease periods, but relapses are inevitable. Aim: To report our experience with AT in multiple myeloma, between 1994 and 2003. Material and Methods: Retrospective analysis of 20 patients (12 women), with a mean age of 51.1 years. VAD (vincristine, doxorubicin and dexamethasone) was used as initial therapy in 19 patients. High dose cyclophosphamide (11 patients) and variations of VAD regimen (7) associated with granulocyte colony stimulating factor were used for peripheral-blood stem cell harvest. The conditioning regimen consisted of melphalan 200 mg/m2 followed by the reinfusion of peripheral-blood stem cells 24 hours later. The median number of CD34 cells infused was 3,3x106/kg. Three patients were subjected to a second auto graft and one to a non-myeloablative transplant. Mean follow up was 35.5 months. Results: Mucositis and febrile neutropenia were common complications. The median number of days for neutrophyl engraftment was 9 (range 8-11) and for platelets, 10 (range 7-13). No patient died. Complete remission was obtained in 60% (12/20), progession-free survival was 30 months and overall median survival, 47 months. Conclusions: The AT with high-dose melphalan is a safe procedure in our hospital, without mortality and engraftment in all the patients. Complete remission and progression free survival were similar to those reported abroad but the overall median survival was lower.

[Frequency and characteristics of aspirin resistance in Chilean cardiovascular patients]. / Frecuencia y características de la resistencia a aspirina en pacientes cardiovasculares chilenos.

BACKGROUND: Studies performed in Anglo-Saxon countries show that 5% of patients are resistant to the antiplatelet effects of aspirin. AIM: To assess the prevalence of aspirin resistance in a sample of Chilean cardiovascular patients and its association with clinical and laboratory characteristics. PATIENTS AND METHODS: Ninety nine patients (30 women, 63+/-10 years) treated for stable cardiovascular diseases with aspirin 100-325 mg/day were studied. Clinical and basic coagulation variables were assessed. Platelet aggregation was studied with platelet rich plasma using three different agonists in an optical aggregometer. Aspirin resistance was defined as an aggregation 20% with arachidonic acid and an aggregation 70% with ADP or collagen. RESULTS: Eleven patients (11.11%, 95% CI= 4.95-17.27%) complied with both criteria and were classified as aspirin resistant. Current smoking was more common in aspirin resistant patients (63.6 vs 29.6%, p=0.039). CONCLUSIONS: Aspirin resistance was found in a significant proportion of cardiovascular patients and was more common among current smokers.

Proteína S libre en embarazadas normales: comparación entre dos métodos / Free protein S (PS) in normal pregnancy: A comparison between two analytical methods

Background: Pregnancy is a physiological hypercoagulable state with an increased incidence of thromboembolic phenomena. There is an increase in the concentrations of most clotting factors, a decrease in concentration of some of the natural anticoagulants and reduced fibrinolytic activity. Changes in PS levels have also been reported. Aim: To establish referral range values of functional PS and free PS antigen, during the second (2nd T) and third trimester (3rd T) of normal gestation. Patients and methods: Forty one normal pregnant women were included in our study, 20 during the 2nd T (22-24 weeks) and 21 during the 3rd T (29-38 weeks). Functional PS was measured by a clot based test and free PS antigen by ELISA. Results: Free PS Antigen was 65.8±18.3% during the 2nd T and 62.3±16.5% during the 3rd T. The figures for normal controls were 106±6.5%. Functional PS was 43.8±13.3 and 25.9±14.6% during the 2nd T and 3rd T, respectively. The figures for normal controls were 97±24% (p <0.001 compared with pregnant women). Free PS antigen did not change from the 2nd to the 3rd T (p=NS), however functional PS fell significantly from the 2nd to the 3rd T (p <0.001) and was significantly lower than free PS antigen in both trimesters (p <0.001). Conclusions: Pregnancy is associated to a decrease in PS. This abnormality is more pronounced for functional PS than free PS antigen and functional PS falls progressively during pregnancy. These assays should not be used to screen for PS deficiency during pregnancy because they could lead to a misdiagnosis.