Therapeutic Levels Of Anticoagulation Research Articles

Activated Partial Thromboplastin Time Monitoring of Unfractionated Heparin Therapy: Issues and Recommendations.

When administering unfractionated heparin (UFH), therapeutic levels of anticoagulation must be achieved rapidly and maintained consistently in the therapeutic range. The basic assays for monitoring UFH therapy are the activated partial thromboplastin time (APTT) and/or the chromogenic antifactor Xa or antithrombin assays. For many laboratories, the APTT is the preferred standard of practice; however, the APTT is a surrogate marker that only estimates the heparin concentration. Many factors, including patient variation, reagents of the APTT, UFH composition, and concentration can influence the APTT result. This article reviews various methods to determine the heparin therapeutic range and presents recommendations for the laboratory to establish an APTT heparin therapeutic range for all sizes of hospitals.

Intravenous heparin dosing strategy in hospitalized patients with atrial dysrhythmias.

Patients with non-valvular atrial fibrillation (AF) have an elevated stroke risk that is 2-7 times greater than in those without AF. Intravenous unfractionated heparin (UFH) is commonly used for hospitalized patients with atrial fibrillation and atrial flutter (AFL) to prevent stroke. Dosing strategies exist for intravenous anticoagulation in patients with acute coronary syndromes and venous thromboembolic diseases, but there are no data to guide providers on a dosing strategy for intravenous anticoagulation in patients with AF/AFL. 996 hospitalized patients with AF/AFL on UFH were evaluated. Bolus dosing and initial infusion rates of UFH were recorded along with rates of stroke, thromboemobolic events, and bleeding events as defined by the International Society on Thrombosis and Haemostasis criteria. Among 226 patients included in the analysis, 76 bleeding events occurred. Using linear regression analysis, initial rates of heparin infusion ranging from 9.7 to 11.8units/kilogram/hour (U/kg/h) resulted in activated partial thromboplastin times that were within therapeutic range. The median initial infusion rate in patients with bleeding was 13.3U/kg/h, while in those without bleeding it was 11.4U/kg/h; p=0.012. An initial infusion rate >11.0 U/kg/h yielded an OR 1.95 (1.06-3.59); p=0.03 for any bleeding event. Using IV heparin boluses neither increased the probability of attaining a therapeutic aPTT (56.1 vs 56.3%; p=0.99) nor did it significantly increase bleeding events in the study (35.7 vs 31.3%; p=0.48). The results suggest that higher initial rates of heparin are associated with increased bleeding risk. From this dataset, initial heparin infusion rates of 9.7-11.0U/kg/h without a bolus can result in therapeutic levels of anticoagulation in hospitalized patients with AF/AFL without increasing the risk of bleeding.

To achieve target international normalized ratio with concurrent warfarin and rifampicin therapy is a challenge: a case report and review of literature

<p>A 60-year-old man with a history of deep vein thrombosis put on anticoagulation therapy with warfarin 2 mg daily. Achieving a therapeutic level of anticoagulation was difficult despite escalating doses of warfarin, because of the interaction with rifampicin. A 5 to 6 fold increase in warfarin dose was prescribed to reach therapeutic international normalized ratios (INRs), but even these increases were insufficient to maintain his INR in the therapeutic range. After rifampicin was discontinued, warfarin doses were gradually reduced over the next 2 months. When concurrent warfarin-rifampicin therapy is necessary, vigilant monitoring of INR is imperative and rifampicin should be stopped. Warfarin is an oral anticoagulant used to get target INR to prevent thrombosis in various cardiovascular diseases. Its metabolism is affected by dugs, diet and individual characteristics. It is metabolized in liver by microsomal cytochrome P450 enzyme. Rifampicin is an essential component of first line antitubercular regimen. It induces enzyme P450, responsible for metabolism of warfarin. So to get target INR 2.5 to 3.5 is very difficult even with maximum possible dose of warfarin when patient taking simultaneously both drugs. In this case, rifampicin was stopped to achieve target INR. Tuberculosis patient on warfarin should not take rifampicin as component of first line antitubercular regimen.</p>

Delayed anticoagulation is associated with poor outcomes in high-risk acute pulmonary embolism

PurposeEarly diagnosis and timely treatment are essential to improve the outcomes of pulmonary embolism (PE), but no study has investigated the impact of anticoagulation timing on clinical outcomes in high-risk acute PE patients. We analyzed the relationship between early anticoagulation initiation and in-hospital mortality in high-risk acute PE patients at the intensive care unit (ICU) of a teaching hospital. Materials and methodsSeventy-three PE patients admitted to the ICU were included in this retrospective study. Demographic, clinical, radiological, and therapeutic data were collected on ICU admission, and the timings of diagnosis and anticoagulation initiation were analyzed. ResultsThe number of survivors was 67. The median time from hospital arrival to the start of anticoagulation therapy was significantly lower in survivors (3.6 [2.6-5.0] hours) than nonsurvivors (5.7 [4.5-14.9] hours; P = .03). However, the median time required to achieve a therapeutic anticoagulation level was comparable between survivors and nonsurvivors (12.0 [9.5-19.5] vs 16.4 [10.7-27.4] hours; P = .488). Ventilatory support and vasopressor use were found to be associated with higher in-hospital mortality. ConclusionsDelayed anticoagulation is an important prognostic factor of poor outcomes in high-risk acute PE patients.

Anticoagulation dilemma in a high-risk patient with On-X valves

Thromboembolism continues to be a major concern in patients with mechanical heart valves, especially in those with unsatisfactory anticoagulation levels. The new On-X valve (On-X Life Technologies, Austin, TX, USA) has been reported as having unique structural characteristics that offer lower thrombogenicity to the valve. We report a case where the patient received no or minimal systemic anticoagulation after placement of On-X mitral and aortic valves due to development of severe mucosal arterio-venous malformations yet did not show any evidence of thromboembolism. This case report reinforces the findings of recent studies that lower anticoagulation levels may be acceptable in patients with On-X valves and suggests this valve may be particularly useful in those in whom therapeutic levels of anticoagulation cannot be achieved due to increased risk of bleeding.

Warfarin monitoring in antiphospholipid syndrome and lupus anticoagulant.

To review the available literature on international normalized ratio (INR) and chromogenic factor X (CFX) monitoring in patients with antiphospholipid syndrome (APS), specifically lupus anticoagulant (LA), and furthermore, to identify benefits of one monitoring test compared with the other in the presence of LA. A literature search was conducted through MEDLINE (1946-May 2014) utilizing the following MeSH terms chromogenic compounds, anticoagulants, and factor X. Further articles were identified from original literature citations. All English-language studies were included that involved INR and/or CFX monitoring in APS patients that focused on a therapeutic anticoagulation level with warfarin therapy. A total of 55 articles were identified, of which nine are referenced because of their relevance for this review: three articles focus on the efficacy of utilizing INR monitoring in patients with APS, five focus on CFX compared with INR for therapeutic warfarin dosing, and one compares different thromboplastins utilizing both INR and CFX monitoring. INR monitoring in patients with APS, specifically LA, was not found to be reliable because thromboplastin reagents are sensitive to LA. Furthermore, when INR was compared to CFX, patients with LA had supratherapeutic INRs despite having CFX within goal range. In a subgroup of APS patients, INR monitoring may not be safe for determining the dose of warfarin because their INR values can be falsely elevated. Although CFX monitoring is more accurate, it too comes with its own downsides. Managing warfarin therapy in the APS population needs to be individualized.

Control del sangrado postoperatorio en pacientes anticoagulados empleando colutorios de ácido tranexámico. Implicancias de la periodontitis

Se analizó el efecto hemostático clínico del colutorio de ácido tranexámíco frente altratamiento convencional en pacientes tratados con anticoagulantes orales. Los procedimientos quirúrgicos (exodoncias) se llevaron a cabo después de suspender la medicación anticoagulante tres días, en 10 pacientes quienes fueron sometidos a 10 procedimientos (grupo control) y sin modificar el tratamiento anticoagulante, en 15 pacientes en quienes se realizaron 20 procedimientos empleando además colutorios de ácido tranexámico (grupo casos). En este último grupo, antes de suturar, el campo operatorio fue irrigado con la solución de ácido tranexámico (agente antifibrinolítico) al 5%. Posteriormente, los pacientes del grupo casos fueron instruidos para emplear 1Oml del colutorio por dos minutos, cuatro veces al día por siete días. La única diferencia estadísticamente significativa (p<0,05) entre los dos grupo de tratamiento. al inicio del estudio, fue el nivel de anticoagulación. El INR promedio para el grupo casos y control fue de 2,53 y 1,13 respectivamente. No hubo diferencias significativas entre los dos grupos de tratamiento en la incidencia de sangrado postoperatorio. Los resultados demostraron que el ácido tranexámico es eficaz para controlar el sangrado postoperatorio y que el estado periodontal, particularmente la periodontítis aguda, está más asociado con los eventos de sangrado que el nivel de anticoagulación terapéutico.

Weight-adjusted dosing of tinzaparin in pregnancy

BackgroundLow molecular weight heparin (LMWH) is the preferred anticoagulant for the prevention and treatment of VTE in pregnancy. While dosing of LMWH based on weight alone is standard for most non-pregnant patients, there is no data on the utility of this approach in pregnancy. ObjectivesTo determine whether dosing of tinzaparin by current maternal weight, with adjustment for increasing weight, will achieve adequate levels of anticoagulation throughout pregnancy (target peak anti-Factor-Xa activity levels between 0.5–1.2IU/ml). Patients/MethodsConsecutive pregnant women with acute VTE or requiring high-risk thromboprophylaxis (recurrent VTE, on long-term anticoagulation) at a single centre were approached for enrollment. Subjects were weighed and prescribed tinzaparin 175IU/kg SC once daily and a peak anti-Factor-Xa level was determined. Re-dosing and monitoring was repeated monthly, and subjects were withdrawn from weight-based dosing if consecutive anti-Factor-Xa levels were outside the target range. Subsequent dosing of tinzaparin was titrated to achieve a level in the target range in these women. ResultsThirteen subjects were recruited between January 2008 and May 2010, with one drop out lost to follow-up. Weight-based dosing failed to maintain therapeutic anticoagulation in 11 (92%) of women (95% CI 0.2% to 38.5%). The estimated dose requirement of tinzaparin per trimester increased from 14255IU in the first trimester to 16533IU in the second trimester to 17828IU in the third trimester (p<0.001). The estimated dose/kg required to maintain therapeutic anticoagulation increased across trimesters: 188.0IU/kg in the first trimester, 201.3IU/kg in the second trimester, and 208.6IU/kg in the third trimester (p=0.004). Treatment was well tolerated and no serious bleeding or recurrent thrombotic events occurred. ConclusionsWeight-based dosing of tinzaparin failed to achieve therapeutic anticoagulation in the vast majority of women, although clinical outcomes were good. Doses of tinzaparin in excess of the manufacturer's recommended weight-based dose were required to maintain therapeutic levels of anticoagulation.

Catheter ablation of atrial fibrillation: the need for studies to assess the efficacy and safety of novel anticoagulants

For selected patients with atrial fibrillation (AF), catheter ablation is an important treatment alternative and has about a 70 % success rate in carefully selected patients. Patients undergoing this procedure are at an increased risk of thromboembolic events during and following the ablation procedure. Bridging of anticoagulation, insertion of sheaths and catheters, left atrial endothelial damage, and atrial stunning may all lead to this increased thromboembolic risk. In order to minimize these thromboembolic events, anticoagulation, initiated as part of the procedure, increases bleeding complications including pericardial tamponade and vascular complications. Controlled data are not available to guide anticoagulation management of such patients during the peri-ablation period. Several years ago, we used to discontinue warfarin for several days before the procedure and the anticoagulation bridged with subcutaneous low molecular weight heparin (LMWH). The main limitation of this approach is that patients require LMWH after the procedure until the international normalized ratio (INR) becomes therapeutic. Excessive anticoagulation with LMWH and periods of subtherapeutic INR on warfarin post-procedure, have resulted in bleeding and thrombo-embolic complications [1]. More recently, in order to reduce these limitations, it has become more common to perform the ablation procedure without discontinuation of warfarin [2–4]. Several studies have demonstrated that uninterrupted warfarin is associated with fewer bleeding complications compared to LMWH bridging. With both approaches, unfractionated heparin is administered during the procedure and the dosing regimen is guided by a target activated clotting time (ACT) ranging from 225 to 450. Heparin infusion is discontinued once all catheters have been removed and the sheaths are removed once the ACT is less than 200 s. Post-procedure LMWH is usually not required since the patient is on a therapeutic level of anticoagulation with warfarin. Anticoagulation is then continued for 3–6 months or indefinitely depending on the patient’s risk factors. The problem with the above protocols is that there is no gold standard based on carefully collected prospective controlled data and the FDA has never approved LMWH bridging as an indication for this type of perioperative use. The commercial approval of dabigatran and rivaroxaban (and soon apixaban and edoxaban) has created a new anticoagulation challenge for AF patients undergoing catheter ablation procedures. Dabigatran has been commercially available for about 2 years and several reports have been published related to the safety and efficacy of using this drug during AF ablation procedures. Winkle et al. [5] demonstrated dabigatran to be safe and well tolerated when used after AF ablation (interrupted use prior to the ablation procedure) in a single-center study. The study included patients previously treated with warfarin, dabigatran, or aspirin. The post-procedure use of dabigatran was not associated with any major bleeding or thromboembolic events. However, three patients had to stop dabigatran due to dyspepsia, rash, and diarrhea. In this study, dabigatran was discontinued 36– 60 h prior to the procedure based on renal function and restarted 22 h after the procedure (post-procedure LMW heparin was given). The target ACT during the procedure was 225 s. A larger multicenter study by Lakkireddy et al. [6] reported that periprocedural dabigatran use significantly G. V. Naccarelli (*) :M. D. Gonzalez Electrophysiology Program, Heart and Vascular Institute, Penn State University College of Medicine, 500 University Drive, Room H1511, P. O. Box 850, MC H047, Hershey, PA 17033, USA e-mail: gnaccarelli@hmc.psu.edu

Heparin - a Key Drug in the Treatment of the Circulatory Degenerative Diseases: Controlling its Action with Polymers

The properties of heparin, a key anticoagulant, are reviewed. The important issues in heparinotherapy, i.e., reaching quick anticoagulant effect, maintaining therapeutic level of anticoagulation, heparin inhibition and non-invasive heparin formulations have been reviewed and discussed, with the focus on the role of polymeric substances in the proposed solutions.

Interpretation of Point-of-care INR Results in Patients Treated with Dabigatran

BackgroundPoint-of-care devices for measurement of the international normalized ratio (INR) are commonly used to monitor therapy and maintain therapeutic levels of anticoagulation in patients treated with vitamin K antagonists. Dabigatran, a new oral, reversible direct thrombin inhibitor approved for stroke prevention in patients with atrial fibrillation does not require routine coagulation monitoring. However, case reports have identified falsely elevated point-of-care INR levels in patients treated with dabigatran using one of these devices (Hemochron). This in vitro study was designed to verify this issue. MethodsWe compared INR levels in whole blood and plasma using a Hemochron Jr. Signature+ point-of-care device (International Technidyne Corporation, Edison, NJ) with routine laboratory monitoring, using blood from healthy volunteers that was spiked with increasing concentrations of dabigatran. ResultsProthrombin time and INR levels were increased about 2- to 4-fold with the point-of-care device compared with laboratory measures across the plasma dabigatran concentration range 50-1400 ng/mL. At plasma concentrations of dabigatran likely to be observed in patients, at a dose of 150 mg twice daily (60-275 ng/mL), whole blood point-of-care INR values increased from 1.7 to 4.0, versus 1.1 to 1.5 measured with the laboratory coagulometer. Similar differences in prothrombin time were observed in plasma samples. ConclusionsINR levels in patients taking dabigatran are substantially higher using a Hemochron Jr. point-of-care device compared with laboratory values. We discourage the use of these devices specifically, as well as the use of the INR in general, for measuring the anticoagulant effect of dabigatran.

Abstract P138: Quality Improvment Strategy for Better Control of Warfarin Anticoagulaton in Outpatients

Introduction: Warfarin is currently the only effective oral anticoagulant for thromboembolic prophylaxis in patients at high risk for stroke or other thromboembolic complications. Maintaining a therapeutic level of anticoagulation as measured by the International Normalized Ratio (INR) can be challenging, due to genetic differences in drug metabolism, multiple drug interactions, and variations in dietary vitamin K intake. We designed a program to improve our ability to keep our patients' INR within the therapeutic range. Methods: We established a baseline degree of INR control in the fall of 2007, measuring the INR for 50 sequential patients who required warfarin therapy for at least one month for each of our 5 physicians; therapeutic range was 2-3 for most indications, or 2.5-3.5 for mechanical valves. We then instituted an INR improvement program, making certain our office gave directions for subsequent warfarin dosing and the next INR testing directly to the patient only; reviewing all drugs and potential interactions at each contact; reviewing potential dietary and alcohol consumption issues at each contact; and utilizing a standard dosing protocol for any dose changes. We reassessed the degree of INR control 6 months later and 18 months later in a similar cohort, measuring 50 sequential patients for each of our 5 physicians. Results: At our most recent survey, the average age of our patients was 73.7 and 43% (108 of 250) were female. The indication for anticoagulation was atrial fibrillation in 81.6% (204 of 250), mechanical heart valve in 11.2% (28 of 250), and other indications in 7.2% (18 of 250). The percentage of patients within their therapeutic range was 62.4% (156 of 250) at the baseline survey, 66.0% (165 of 250) at the second survey, and 65.6% (164 of 250) at the most recent survey, p=0.42 comparing first to second, p=0.45 comparing first to third, and p=0.92 comparing second to third, none significantly different. Conclusion: Achieving and maintaining a therapeutic INR with warfarin dosing even with an aggressive quality improvement program is a continuing therapeutic challenge. More effective management strategies or alternative anticoagulants which may be simpler to manage remain a high priority.

Guidelines on oral anticoagulation with warfarin – fourth edition

Guidelines on oral anticoagulation with warfarin – fourth edition

Anticoagulation Therapy Following Embolic or Hemorrhagic Stroke in the Patient with a Mechanical Heart Valve

Background: An estimated 95,000 heart valve replacements are performed annually in the United States. Prosthetic valves may be either mechanical or bioprosthetic in composition. Mechanical valves offer added durability but commit the patient to taking lifelong anticoagulant therapy. Maintaining therapeutic levels of anticoagulation may be challenging, and inadequate anticoagulation can lead to thromboembolic or hemorrhagic complications. When a patient with a mechanical valve suffers a stroke, management of anticoagulation becomes more controversial and complicated. This article reviews the available evidence and guidelines for management of systemic anticoagulation following stroke in patients with mechanical heart valves. Methods: A review of the PubMed database for pertinent articles, using the keywords “mechanical heart valve”, “anticoagulation”, “cerebrovascular accident”, and “stroke”. The clinical guidelines offered by the American College of Cardiology, American Heart Association, and American Stroke Association were also reviewed. Results: There are no definitive guidelines for the management of patients with mechanical heart valves who suffer a stroke. Most of the data is from small case series and retrospective reviews. Conclusion: Based on the available data, anticoagulation should be resumed rapidly following thromboembolic stroke in patients with a mechanical heart valve, once the risk of hemorrhagic transformation has declined. In the setting of a hemorrhagic stroke, it also appears safe to resume anticoagulation relatively rapidly (after approximately one week), although the risks of further bleeding must be considered. In either case, holding anticoagulation after a stroke for a few days does not expose the patient to significantly increased risk of acute thrombosis.

Factor Xa and thrombin as targets for new oral anticoagulants

Although currently available anticoagulants are effective for the prevention and treatment of thromboembolic disorders, they have several drawbacks. Low molecular weight heparin and fondaparinux produce a predictable level of anticoagulation that obviates the need for coagulation monitoring, but they must be given parenterally, which renders them inconvenient for long-term use. Vitamin K antagonists, such as warfarin, are administered orally, but produce a variable anticoagulant response because genetic polymorphisms, dietary vitamin K intake and multiple drug-drug interactions affect their metabolism. Consequently, coagulation monitoring and frequent dose adjustments are needed to ensure that a therapeutic level of anticoagulation is achieved. This is burdensome for patients and physicians, and costly for the healthcare system. These limitations have prompted the development of new oral anticoagulants that target thrombin or factor Xa. The new agents produce such a predictable anticoagulant response that they can be given in fixed doses without monitoring. This paper focuses on the new oral anticoagulants in the most advanced stages of development.

Anticoagulant Therapy for Percutaneous Coronary Intervention

Received June 2, 2009; accepted November 16, 2009. Percutaneous coronary intervention (PCI) is the most commonly performed invasive therapeutic cardiac procedure and plays an important role in the treatment of ischemic heart disease. Since the first description of coronary angioplasty in a human by Gruntzig,1 the technique, equipment, and associated pharmacotherapy have undergone substantial evolution, leading to significant improvements in periprocedural complications.2 In particular, procedural anticoagulant therapy has been the focus of numerous clinical trials, and several options are now available and supported by practice guidelines; each agent has both advantages and disadvantages, and procedural pharmacotherapy continues to be a focus of drug development. The purpose of this review is to summarize the goals of anticoagulant therapy during PCI, the pharmacokinetics and pharmacodynamics of available agents, and the clinical data surrounding each agent and to identify new agents in development. The goals of pharmacotherapy during PCI are 2-fold: (1) to mitigate the sequelae of iatrogenic plaque rupture from balloon angioplasty or stenting and (2) to reduce the risk of thrombus formation on intravascular PCI equipment. Central to these thrombotic events is thrombin (factor IIa). Iatrogenic damage to the endothelium during PCI leads to increased expression of tissue factor, activation of the coagulation cascade, and formation of activated factor Xa. This ultimately leads to the generation of thrombin, conversion of fibrinogen to fibrin, and thrombus formation.3 In addition to its effects on fibrin, thrombin also directly activates platelets, enhances platelet aggregation, and is proinflammatory.4 Because of its multiple actions in promoting thrombosis, the focus of most anticoagulant agents is thrombin inhibition. Available agents for use include unfractionated heparin (UFH), low-molecular-weight heparins (LMWH, of which enoxaparin has the largest body of clinical data), the synthetic pentasaccharides (of which fondaparinux has the largest body of clinical data), and the …

Small intestinal bacterial overgrowth and warfarin dose requirement variability

The dose of warfarin needed to obtain a therapeutic anticoagulation level varies widely among patients and can undergo abrupt changes for unknown reasons. Drug interactions and genetic factors may partially explain these differences. Intestinal flora produces vitamin K 2 (VK 2) and patients with small intestinal bacterial overgrowth (SIBO) rarely present reduced INR values due to insufficient dietary vitamin K. The present study was undertaken to investigate whether SIBO occurrence may affect warfarin dose requirements in anticoagulated patients. Based on their mean weekly dose of warfarin while on stable anticoagulation, 3 groups of 10 patients each were defined: low dose (LD, ≤ 17.5 mg/wk of warfarin); high dose (HD, from 35-70 mg/wk); and very high dose (VHD ≥ 70 mg/wk). Each patient underwent a lactulose breath test to diagnose SIBO. Plasma levels of warfarin and vitamin K-analogues were also assessed. Patients with an altered breath test were 50% in the VHD group, 10% in the HD group, and none in the LD group (P = 0.01). Predisposing factors to SIBO were more frequent in the VHD group, while warfarin interfering variables were not. VHD patients were younger and had a higher plasma vitamin K 1 (VK 1) concentration (P > 0.05). On the contrary, the plasma VK 2 levels tended to be lower. This pilot study suggests that SIBO may increase a patient's warfarin dose requirement by increasing dietary VK 1 absorption through the potentially damaged intestinal mucosa rather than increasing intestinal VK 2 biosynthesis. Larger studies are needed to confirm these preliminary data and to evaluate the effects of SIBO decontamination on warfarin dosage.

New oral anticoagulants in development

Although currently available anticoagulants are effective for the prevention and treatment of thromboembolic disorders, they have several drawbacks. Low-molecular-weight heparins and fondaparinux produce a predictable level of anticoagulation that obviates the need for coagulation monitoring, but they must be given parenterally, which renders them inconvenient for long-term use. Vitamin K antagonists, such as warfarin, are administered orally, but produce a variable anticoagulant response because genetic polymorphisms, dietary vitamin K intake and multiple drug-drug interactions affect their metabolism. Consequently, coagulation monitoring and frequent dose adjustments are needed to ensure that a therapeutic level of anticoagulation is achieved. This is burdensome for patients and physicians, and costly for the healthcare system. These limitations have prompted the development of new oral anticoagulants that target thrombin or factor Xa and can be given in fixed doses without coagulation monitoring. This paper focuses on the new oral anticoagulants in the most advanced stages of development.

Sobreanticoagulación con Warfarina

El uso de la warfarina está asociado con la aparición de Reacciones Adversas Medicamentosas como la sobreanticoagulación, esto genera más morbilidad, hospitalizaciones y mayor riesgo de sangrado en los ancianos a través de asociaciones con otras enfermedades e interacciones con medicamentos y alimentos. Este anticoagulante es un cumarínico que actúa a través de la inhibición de los factores de la vía extrínseca de la coagulación, por medio de su efecto en ciclo de la Vitamina K, y se vigila con el International Normalized Ratio (INR) hallándose más probabilidad de hemorragia con valores por encima de 4. El enfoque y manejo de los INR elevados debe estar basado en las características del paciente y la categoría de sangrado para decidir la necesidad del uso de Vitamina K, Plasma Fresco Congelado o Concentrado de Complejos de Protrombina permitiendo así un retorno seguro a niveles terapéuticos de anticoagulación.

Locoregional anesthesia and anticoagulation

Spinal hematoma is a rare and potentially catastrophic complication of spinal or epidural anesthesia. Risk factors include traumatic needle/catheter placement, sustained anticoagulation in an indwelling neuraxial catheter, and catheter removal during therapeutic levels of anticoagulation. Generally, a patient’s coagulation status should be optimized at the time of spinal or epidural needle/catheter placement, and the level of anticoagulation should be monitored during epidural catheterization. Signs of cord compression, such as severe back pain, progression of numbness or weakness, and bowel and bladder dysfunction, warrant immediate radiographic evaluation. A delay in diagnosis and intervention of spinal hematoma may lead to irreversible cord ischemia.