Suspensión de la anticoagulación oral en pacientes con fibrilación auricular ante un procedimiento invasivo: ¿deben recibir un puenteo con anticoagulación parenteral durante su realización? / Suspension of oral anticoagulation in patients with atrial fibrillation before an invasive procedure: should they receive parenteral anticoagulation bridging during its implementation?

En la actualidad, muchos pacientes con fibrilación auricular son anticoagulados por largos períodos. Durante este tiempo pueden ser sometidos a procedimientos invasivos. A partir de una viñeta clínica, un médico se plantea el impacto de utilizar o no heparina de bajo peso molecular como puente farmacológico al momento de suspender la anticoagulación oral. Luego de realizar una búsqueda ad hoc, un ensayo clínico aleatorizado de no inferioridad demuestra que en pacientes con fibrilación auricular, con puntajes de riesgo tromboembólico (CHADS2) intermedios a bajos que requieren una interrupción temporal del tratamiento con warfarina para un procedimiento invasivo electivo, la estrategia de no reemplazar la anticoagulación oral con heparina de bajo peso molecular no resultó inferior (o menos efectiva) para la prevención de tromboembolismo arterial, y disminuyó además el riesgo de sangrado mayor en comparación al uso de un puente con esta medicación. (AU)

Many patients with atrial fibrillation are anticoagulated for long periods. During this time they may be subjected to invasive procedures. From a clinical vignette, a physician discusses the impact of using (or not) low molecular weight heparin as a pharmacological bridge at the time of suspending oral anticoagulation. After conducting a bibliographic search, a no inferiority randomized clinical trial showed that in patients with atrial fibrillation with intermediate to low thromboembolic risk (CHADS2) requiring a temporary interruption of warfarin therapy for an elective invasive procedure, the strategy of with holding low molecular weight heparin bridging was not inferior (or less effective) for the prevention of arterial thromboembolism than its use, also decreasing the risk of major bleeding. (AU)

Catéter subcutáneo para la administración de heparina de bajo peso molecular en pediatría / Subcutaneous catheter used for administration of low-molecular-weight-heparin in pediatrics

Introduction: Subcutaneous catheter is a device easy to assemble, which was created for the administration of insulin in diabetic patients, especially in children, aiming to reduce the number of punctures, pain and anxiety of patients and their parents. Objective: To describe the experience using the catheter for subcutaneous administration of low molecular weight heparin (LMWH) in hospitalized pediatric patients. Patients and Method: A prospective descriptive study in 28 patients who used 87 subcutaneous catheters for the administration of LMWH in the Pediatric Service of the Universidad Catolica de Chile between July, 2010 and November, 2011. Results: Complications associated with the catheter had an incidence of 33 percentin total catheters evaluated; the most frequent complication was the presence of hematoma at the site of insertion (26 percent). These complications occurred more frequently in male (38 percent versus 31 percent in females) and younger patients (9 months versus 12 months), who received dalteparin (54 percent versus 30 percent of other types of heparin) administered every 24 hours (41percent versus 30 percent, administered every 12 hours), and when the catheter was located on both thighs (36 percent versus 32 percent in both arms); however, these differences were not statistically confirmed. Conclusion: The subcutaneous catheter is a good technique to be considered for LMWH in children as it presents minor complications for drug administration.

Introducción: El catéter subcutáneo es un dispositivo de fácil instalación, el cual fue ideado para la administración de insulinas en pacientes diabéticos, especialmente en pediatría, con el fin de disminuir el número de punciones, el dolor y la ansiedad de los pacientes y sus padres. Objetivo: Describir la experiencia del uso del catéter subcutáneo para la administración de heparina de bajo peso molecular (HBPM) en pacientes pediátricos hospitalizados. Pacientes y Método: Estudio descriptivo prospectivo en 28 pacientes que utilizaron 87 catéteres subcutáneos instalados para la administración de HBPM, en el Servicio de Pediatría de la Pontificia Universidad Católica de Chile en el período comprendido entre los meses de julio de 2010 y noviembre de 2011. Resultados: Las complicaciones asociadas al catéter presentaron una incidencia de 33 por ciento en el total de catéteres evaluados, siendo la más frecuente la presencia de hematoma en el sitio de inserción (26 por ciento). Estas complicaciones se presentaron con mayor frecuencia en pacientes de sexo masculino (38 por ciento versus 31 por ciento en sexo femenino) de menor edad (9 meses versus 12 meses), con indicación de dalteparina (54 por ciento versus 30 por ciento con otros tipos de heparina) administrada cada 24 h (41 por ciento versus 30 por ciento cuando fue administrada cada 12 h), y cuando el catéter estuvo ubicado en ambos muslos (36 por ciento versus 32 por ciento en ambos brazos); sin embargo, estas diferencias no fueron confirmadas estadísticamente. Conclusión: El catéter subcutáneo es una buena técnica a considerar para la administración de HBPM en la edad pediátrica, ya que permite la administración del medicamento con complicaciones leves asociadas a su uso.

The use of Low Molecular Weight Heparin to Predict Clinical Outcome in Patients with Unstable Angina That Had Undergone Percutaneous Coronary Intervention

BACKGROUND: Antithrombotic therapy with heparin reduces the rate of ischemic events in patients with acute coronary syndrome. Low-molecular-weight heparin, given subcutaneously twice daily, has a more predictable anticoagulant effect than standard unfractionated heparin. Moreover, it is easier to administer and does not require monitoring. METHODS: We prospectively analyzed 180 patients with unstable angina who had undergone percutaneous coronary intervention (PCI) between 1999 and 2001 at Chonnam National University Hospital and had received either 120 U/kg of dalteparin (Fragmin (R) ), administered subcutaneously twice daily (Group I; n=90, 61.8 +/- 8.9 years, male 67.8%), or had received continuous intravenous unfractionated heparin (Group II; n=90, 62.6 +/- 9.7 years, male 70.0%). During hospitalization and at 6 month after PCI, major adverse cardiac events such as acute myocardial infarction, target vessel revascularization, death, and restenosis were examined. RESULTS: During hospitalization, the incidence of acute myocardial infarction, target vessel revascularization and death were not different between the two groups. At follow-up coronary angiography 6 months after PCI, the incidence of restenosis was lower in group I than in group II (Group I; 26/90, 28.8% vs. Group II; 32/90, 35.6%, p=0.041) and the incidence of target vessel revascularization was lower in group I than in group II (Group I; 21/90, 23.3% vs. Group II; 27/90, 30.0%, p=0.039). No difference was found in the rates of major and minor hemorrhages, ischemic strokes or thrombocytopenia between two groups. By multivariate analysis, the factors related to restenosis were lesion length, postprocedural minimal luminal diameter, CRP on admission, diabetes mellitus, the type of heparin, and stent use. CONCLUSION: Dalteparin, a low molecular weight heparin, is superior to standard unfractionated heparin in terms of reducing the restenosis rate and target vessel revascularization without increasing bleeding complications.

Low molecular weight heparin for treatment of acute myocardial infarction (FAMI): Fragmin (dalteparin sodium) in acute myocardial infarction.

The benefit of using subcutaneous low molecular weight heparin for the treatment of acute myocardial infarction is not known. The aim of this study was to determine the efficacy of a low molecular weight heparin (dalteparin sodium) for the treatment of acute myocardial infarction in patients not treated with thrombolytic therapy. Twenty-nine cardiological centres from leading hospitals in India participated in this prospective, multicentre, double-blind, placebo-controlled study in two phases which included 1128 patients with acute myocardial infarction. In the acute phase (between day 1 and 3 of admission) all the patients received a weight-adjusted dose of subcutaneous dalteparin (120 IU/kg twice daily). In the second, double-blind phase of acute myocardial infarction, patients were randomised to receive a fixed dose of dalteparin (7,500 IU) or an identical placebo injection for 30 days. A composite primary endpoint of death, reinfarction, recurrence of angina and emergency revascularisation was used. All the 1128 patients with acute myocardial infarction were included in the trial. In the acute phase, the composite primary endpoint was observed in 58 (5.1%) patients. Of 1037 paients who were randomly assigned to receive a fixed dose of dalteparin (n=519) or placebo (n=518), the composite primary event rate was 6.7 percent and 7.0 percent, respectively (RR 0.97; 95% CI 0.62-1.52; p=0.90). To conclude, treatment with dalteparin administered subcutaneously in a weight-adjusted dose of 120 IU/kg twice daily resulted in a lower than expected mortality during the acute phase of myocardial infarction. A lower fixed once daily dose of 7,500 IU during the chronic phase did not confer additional protection.