ABSTRACT
La anticoagulación con heparinas de bajo peso molecular (HBPM) es una herramienta terapéutica fundamental para el tratamiento de la enfermedad tromboembólica. En el presente reporte se evidencia la importancia de cuantificar la actividad del anticuerpo antifactor X activado (Xa) para el monitoreo de la enoxaparina y analizar los grupos de pacientes en riesgo de tener niveles inferiores al teraputico. Mtodos: se estudiaron 34 pacientes adultos, anticoagulados con enoxaparina durante el periodo 2009-2011. Asimismo, se realizó un análisis descriptivo de las características demográficas y clínicas de todo los pacientes, en donde se indicaron las causas de la anticoagulación, la comorbilidades y el tipo de anticoagulación. Se midió la actividad anti-Xa 4 horas después de la administración de enoxaparina. Resultados: El promedio de edad de los pacientes fue de 62,3+17,7 años. Un 72,71 por ciento de los pacientes utilizaron enoxaparina como indicación para el síndrome coronario agudo. La comorbilidad más importante fue la combinación con la hipertensión arterial. El aclaramiento renal promedio fue de 62,47 ml/min, solamente tres pacientes tuvieron un aclaramiento menor a 30 ml/min; un 44,1 por ciento de los pacientes eran obesos. El 55,9 por ciento de los pacientes tuvo niveles anti-factor Xa dentro del rango terapéutico y un 35,3 por ciento tuvo valores de anti factor Xa profilácticos. Conclusión: El manejo del paciente adulto que recibe terapia anticoagulación con HBPM presenta una alta complejidad, hecho que se ve reflejado tanto a su perfil demográfico como clínico. También, se considera importante contar con la determinación del factor anti Xa para el monitoreo de HBPM para cierto grupo de pacientes vulnerables y con ello lograr el efecto deseado con esta terapia, debido a que existe un alto porcentaje de pacientes con niveles fuera del rango terapéutico.
Anticoagulation is an important therapeutic tool for patients with thromboembolic disease who receive therapy with lowmolecular weight heparins (LMWH). This report gives evidence about the importance of determining the activity of Anti-Xaactivity for monitoring enoxaparin and for identifying those patients who need this analysis based on some risk factors.Methods: We studied 34 adult patients who received enoxaparin as anticoagulation therapy during the period 2009-2011. We performed a descriptive analysis of demographic and clinical characteristics of all patients, indicating thereasons for anticoagulation, comorbidities and type of anticoagulation. We determined the anti-Xa activity 4 hours afteradministration of enoxaparin.Results: The mean age of patients was 62,3 + 17,7 years, regardless of gender. 72,7% of patients received enoxaparin astherapy for an acute coronary syndrome. The most frequent comorbidity was hypertension. The average of renal clearancewas 62,47 ml/min, only three patients had a renal clearance below 30 ml/min. 44,1% of the patients were obese. 55, 9%of patients were within therapeutic levels of anti-Xa activity and 35,3% of patients had an anti-Xa activity considered asprophylactic.Conclusion: The management of adult patients receiving anticoagulation therapy with LMWH is complex and it isreflected in their demographic and clinical characteristics. It is important to determine Anti-Xa activity to monitor the useof enoxaparin as anticoagulant therapy because of the high variability found in certain groups of patients.
Subject(s)
Humans , Male , Female , Middle Aged , Costa Rica , Coronary Disease/diagnosis , Coronary Disease/drug therapy , Factor X , Factor Xa , Heparin, Low-Molecular-Weight , Thromboembolism/diagnosis , Thromboembolism/drug therapyABSTRACT
BACKGROUND: The commonly recommended therapeutic range is an activated partial thromboplastin time(APTT) of 1.5 to 2.5 times the control value, which may be inappropriate for some reagents. The aim of this study is to evaluate the correlation of APTT and anti-Xa activity and to compare two methods of determining the therapeutic range of APTT during unfractionated heparin treatment. METHODS: We measured anti-Xa activity and APTT in 80 plasmas from patients treated with unfractionated heparin. We performed correlation analysis between anti-Xa activity and APTT or APTT ratio(heparinized APTT/baseline APTT). The therapeutic range determined by anti-Xa activity of 0.35-0.7 U/mL was compared with the therapeutic range based on minimizing potential thrombosis and bleeding error. RESULTS: The anti-Xa activity-vs-APTT correlation was slightly, but not significantly, improved by converting APTT(r=0.835) to APTT ratio(r=0.883). The APTT therapeutic range predicted by anti-Xa activity-vs-APTT regression analysis was 68.7 to 139.5 seconds(66.6-127.9 seconds for logarithmatically transformed APTT), whereas the range predicted by minimization-of-error technique was 68 to 97 seconds. CONCLUSIONS: The established therapeutic APTT range based on linear regression analysis was not considered to be optimal. The therapeutic range based on minimizing the potential clinical errors may further improve error rate, but prospective study with a larger number of patient samples would be required to apply in clinical field.
Subject(s)
Humans , Hemorrhage , Heparin , Indicators and Reagents , Linear Models , Partial Thromboplastin Time , Plasma , Thromboplastin , ThrombosisABSTRACT
BACKGROUND AND OBJECTIVES: Standard unfractionated heparin (UFH) has long been used to prevent death and myocardial infarction in patients with acute coronary syndrome and acute occlusion undergoing percutaneous revascularization. However, UFH binds to several plasma proteins, platelets, and endothelial cells producing a highly variable anticoagulant response. In contrast, Low molecular weight heparin (LMWH) exhibits less protein binding and provides more predictable anticoagulant response with reduced need for patient monitoring and dosage adjustment. The purpose of this study was to assess the anti-Xa activities of LMWH in Korean patients with acute coronary syndrome after recommended dose for caucasians and to determine an optimal method of administration of LMWH. MATERIALS AND METHODS: Twenty five patients with acute coronary syndrome were enrolled and allocated to five separate groups (5 patients in each group) by types according to molecular weight (LMWH (A): (molecular weight of 4500 daltons, LMWH (B): molecular weight of 6400 daltons) and methods of administration (Group 1A and 1B: Subcutaneous and subcutaneous injections (SC-SC), Group 2: Intravenous and subcutaneous injections (IV-SC), Group 3A and 3B: Intravenous, subcutaneous and subcutaneous injections (IV-SC-SC). Five groups were as follows: Group 1A: LMWH (A) 1 mg/kg SC every 12 hours, Group 1B: LMWH (B) 100 IU/kg SC every 12 hours, Group 2: LMWH (A) 1 mg/kg IV bolus and 1 mg/kg SC 12 hours later, Group 3A: LMWH (A) 0.5 mg/kg IV bolus, 3 hours later 1 mg/kg SC every 12 hours, Group 3B: LMWH (B) 50 IU/kg IV bolus, 3 hours later 100 IU/kg SC every 12 hours. Anti-Xa activity was measured by amidolytic assay method (Rotachrome, Stago, France) in 555 samples from 25 patients. All the data of anti-Xa activity in each group were plotted along the sequential time and mean values of them were analyzed by Wilcoxon signed rank test. RESULTS: 1)The anti-Xa activity (mean 0.6216+/-0.238 IU/mL) of LMWH (A) was greater than that of LMWH (B)(mean 0.2587+/-0.1709 IU/mL) in the conventional SC-SC method (p<0.001). 2) The anti-Xa activity of LMWH (A) (mean 0.6203+/-0.2383 IU/mL) was also greater than that of LMWH (B)(mean 0.468+/-0.2428 IU/mL) in the IV-SC-SC method (p<0.001). 3) More rapid and effective anti-Xa activities were achieved by IV-SC-SC method compared with conventional SC-SC method. CONCLUSION: This study suggests that immediate achievement and optimum maintenance of anticoagulant activity can be accomplished by IV-SC-SC method rather than conventional SC-SC method in patients of acute coronary syndrome.