Continuous Intravenous Unfractionated Heparin Research Articles

Antithrombin Levels and Heparin Responsiveness during Venoarterial Extracorporeal Membrane Oxygenation: A Prospective Single-center Cohort Study.

Unfractionated heparin, administered during venoarterial extracorporeal membrane oxygenation to prevent thromboembolic events, largely depends on plasma antithrombin for its antithrombotic effects. Decreased heparin responsiveness seems frequent on extracorporeal membrane oxygenation; however, its association with acquired antithrombin deficiency is poorly understood. The objective of this study was to describe longitudinal changes in plasma antithrombin levels during extracorporeal membrane oxygenation support and evaluate the association between antithrombin levels and heparin responsiveness. The hypothesis was that extracorporeal membrane oxygenation support would be associated with acquired antithrombin deficiency and related decreased heparin responsiveness. Adults receiving venoarterial extracorporeal membrane oxygenation were prospectively included. All patients received continuous intravenous unfractionated heparin using a standardized protocol (target anti-Xa 0.3 to 0.5 IU/ml). For each patient, arterial blood was withdrawn into citrate-containing tubes at 11 time points (from hour 0 up to day 7). Anti-Xa (without dextran or antithrombin added) and antithrombin levels were measured. The primary outcome was the antithrombin plasma level. In the absence of consensus, antithrombin deficiency was defined as a time-weighted average of antithrombin less than or equal to 70%. Data regarding clinical management and heparin dosage were collected. Fifty patients, including 42% postcardiotomy, were included between April 2020 and May 2021, with a total of 447 samples. Median extracorporeal membrane oxygenation duration was 7 (interquartile range, 4 to 12) days. Median antithrombin level was 48% (37 to 60%) at baseline. Antithrombin levels significantly increased throughout the follow-up. Time-weighted average of antithrombin levels was 63% (57 to 73%) and was less than or equal to 70% in 32 (64%) of patients. Overall, 45 (90%) patients had at least one antithrombin value less than 70%, and 35 (70%) had at least one antithrombin value less than 50%. Antithrombin levels were not significantly associated with heparin responsiveness evaluated by anti-Xa assay or heparin dosage. Venoarterial extracorporeal membrane oxygenation support was associated with a moderate acquired antithrombin deficiency, mainly during the first 72 h, that did not correlate with heparin responsiveness.

Monitoring of Unfractionated Heparin Therapy in the Intensive Care Unit Using a Point-of-Care aPTT: A Comparative, Longitudinal Observational Study with Laboratory-Based aPTT and Anti-Xa Activity Measurement.

Continuous intravenous unfractionated heparin (UFH) is administered routinely in the intensive care unit (ICU) for the anticoagulation of patients, and monitoring is performed by the activated partial thromboplastin time (APTT) or anti-Xa activity. However, these strategies are associated with potentially large time intervals before dose adjustments, which could be detrimental to the patient. The aim of the study was to compare a point-of-care (POCT) version of the APTT to (i) laboratory-based APTT and (ii) measurements of anti-Xa activity in terms of correlation, agreement and turnaround time (TAT). Thirty-five ICU patients requiring UFH therapy were prospectively included and followed longitudinally for a maximum duration of 15 days. UFH was administered according to a local adaptation of Raschke and Amanzadeh’s aPTT nomograms. Simultaneous measurements of POCT-APTT (CoaguCheck® aPTT Test, Roche Diagnostics) on a drop of fresh whole blood, laboratory-based APTT (C.K. Prest®, Stago) and anti-Xa activity (STA®Liquid anti-Xa, Stago) were systematically performed two to six times a day. Antithrombin, C-reactive protein, fibrinogen, factor VIII and lupus anticoagulant were measured. The time tracking of sampling and analysis was recorded. The overall correlation between POCT-APTT and laboratory APTT (n = 795 pairs) was strongly positive (rs = 0.77, p < 0.0001), and between POCT-APTT and anti-Xa activity (n = 729 pairs) was weakly positive (rs = 0.46, p < 0.0001). Inter-method agreement (Cohen’s kappa (k)) between POCT and laboratory APTT was 0.27, and between POCT and anti-Xa activity was 0.30. The median TATs from sample collection to the lab delivery of results for lab-APTT and anti-Xa were 50.9 min (interquartile range (IQR), 38.4–69.1) and 66.3 min (IQR, 49.0–91.8), respectively, while the POCT delivered results in less than 5 min (p < 0.0001). Although the use of the POCT-APTT device significantly reduced the time to results, the results obtained were poorly consistent with those obtained by lab-APTT or anti-Xa activity, and therefore it should not be used with the nomograms developed for lab-APTT.

Pragmatic Recommendations for the Management of Anticoagulation and Venous Thrombotic Disease for Hospitalized Patients with COVID-19 in Low- and Middle-Income Countries.

ABSTRACTNew studies of COVID–19 are constantly updating best practices in clinical care. Often, it is impractical to apply recommendations based on high-income country investigations to resource limited settings in low- and middle-income countries (LMICs). We present a set of pragmatic recommendations for the management of anticoagulation and thrombotic disease for hospitalized patients with COVID-19 in LMICs. In the absence of contraindications, we recommend prophylactic anticoagulation with either low molecular weight heparin (LMWH) or unfractionated heparin (UFH) for all hospitalized COVID-19 patients in LMICs. If available, we recommend LMWH over UFH for venous thromboembolism (VTE) prophylaxis to minimize risk to healthcare workers. We recommend against the use of aspirin for VTE prophylaxis in hospitalized COVID-19 and non–COVID-19 patients in LMICs. Because of limited evidence, we suggest against the use of “enhanced” or “intermediate” prophylaxis in COVID-19 patients in LMICs. Based on current available evidence, we recommend against the initiation of empiric therapeutic anticoagulation without clinical suspicion for VTE. If contraindications exist to chemical prophylaxis, we recommend mechanical prophylaxis with intermittent pneumatic compression (IPC) devices or graduated compression stockings (GCS) for hospitalized COVID-19 patients in LMICs. In LMICs, we recommend initiating therapeutic anticoagulation for hospitalized COVID-19 patients, in accordance with local clinical practice guidelines, if there is high clinical suspicion for VTE, even in the absence of testing. If available, we recommend LMWH over UFH or Direct oral anticoagulants for treatment of VTE in LMICs to minimize risk to healthcare workers. In LMIC settings where continuous intravenous UFH or LMWH are unavailable or not feasible to use, we recommend fixed dose heparin, adjusted to body weight, in hospitalized COVID-19 patients with high clinical suspicion of VTE. We suggest D-dimer measurement, if available and affordable, at the time of admission for risk stratification, or when clinical suspicion for VTE is high. For hospitalized COVID-19 patients in LMICs, based on current available evidence, we make no recommendation on the use of serial D-dimer monitoring for the initiation of therapeutic anticoagulation. For hospitalized COVID-19 patients in LMICs receiving intravenous therapeutic UFH, we recommend serial monitoring of partial thromboplastin time or anti-factor Xa level, based on local laboratory capabilities. For hospitalized COVID-19 patients in LMICs receiving LMWH, we suggest against serial monitoring of anti-factor Xa level. We suggest serial monitoring of platelet counts in patients receiving therapeutic anticoagulation for VTE, to assess risk of bleeding or development of heparin induced thrombocytopenia.

91-Year-Old Man With Upper Extremity Ecchymoses

91-Year-Old Man With Upper Extremity Ecchymoses

Heparin-Induced Thrombocytopenia in Healthy Individuals with Continuous Heparin Infusion.

The risk for developing heparin-induced thrombocytopenia in healthy individuals is thought to be low, but monitoring recommendations remain controversial. Therefore, a retrospective cohort study was conducted to identify the incidence of thrombocytopenic events in a healthy research population exposed and re-exposed to continuous intravenous (IV) unfractionated heparin. The Division of Sleep Medicine and the Centre for Clinical Investigations at Brigham and Women's Hospital, Boston, Massachusetts, United States, instituted a standardized platelet monitoring procedure for all research protocols that involved heparin to detect platelet count decreases. Protocol-related frequent blood sampling required use of continuous IV unfractionated heparin infusion (5,000 unit/L in 0.45% saline at 40 mL/h) to maintain line patency over extended periods of IV access. From the years 2009 to 2012, a total of 273 healthy volunteers enrolled in Sleep Medicine research protocols met study criteria as having been exposed and/or re-exposed to continuously infused intravenous heparin for at least 4 hours. The mean continuous heparin exposure time was 88 ± 82 SD hours with a total of 397 heparin exposure and re-exposure events. Platelet count measurements were obtained on 629 occasions, representing a range from 2 to 9 draws per participant. No platelet count decrease of more than 50% was detected. There were no detected adverse bleeding or thrombotic events. In this retrospective study of healthy volunteers involved in a rigorously applied inpatient platelet monitoring protocol, heparin exposure and re-exposure did not lower platelet concentration and, therefore, does not appear to be associated with increased risk of HIT in this population.

Subcutaneous unfractionated heparin for the initial treatment of venous thromboembolism.

Venous thromboembolism (VTE) is a prevalent and serious condition. Its medical treatment requires anticoagulation, usually with either unfractionated or low molecular weight heparin (LMWH). Administration of unfractionated heparin (UFH) is usually intravenous (IV) but can be subcutaneous as well. This is an update of a review first published in 2009. To assess the effects of subcutaneous UFH versus intravenous UFH, subcutaneous LMWH or any other anticoagulant drug for the initial treatment of venous thromboembolism. For this update, the Cochrane Vascular Information Specialist searched the Specialised Register (last searched 30 November 2016) and CENTRAL (2016, Issue 10). The Cochrane Vascular Information Specialist also searched trials registries for details of ongoing or unpublished studies. Randomised controlled trials comparing subcutaneous UFH to control, such as subcutaneous LMWH, continuous intravenous UFH or other anticoagulant drugs in participants with acute venous thromboembolism. Two review authors (JS and LR) independently extracted data and assessed the risk of bias in the trials. We used meta-analyses when we considered heterogeneity low. The primary outcomes were symptomatic recurrent venous thromboembolism (deep vein thrombosis and/or pulmonary embolism), VTE-related mortality, adverse effects of treatment including major bleeding, and all-cause mortality. We calculated all outcomes using an odds ratio (OR) with a 95% confidence interval (CI). We included one additional study in this update, bringing the total number of studies in the review to 16 randomised controlled trials, with a total of 3593 participants (1745 participants in the intervention group and 1848 participants in the control group). Eight trials used intravenous UFH as the control treatment, seven trials used LMWH, and one trial had three arms with both drugs as the controls. We did not identify trials comparing subcutaneous UFH with other anticoagulant drugs. We downgraded the quality of the evidence to low due to lack of blinding in studies, which led to a risk of performance bias, and also for imprecision, as reflected by the wide confidence intervals.When comparing subcutaneous versus IV UFH, there was no difference in the incidence of symptomatic recurrent VTE at three months (odds ratio (OR) 1.66, 95% confidence interval (CI) 0.89 to 3.10; 8 studies; N = 965; low-quality evidence), symptomatic recurrent deep vein thrombosis (DVT) at three months (OR 3.29, 95% CI 0.64 to 17.06; 1 study; N = 115; low-quality evidence), pulmonary embolism (PE) at three months (OR 1.44, 95% CI 0.73 to 2.84; 9 studies; N = 1161; low-quality evidence), VTE-related mortality at three months (OR 0.98, 95% CI 0.20 to 4.88; 9 studies; N = 1168; low-quality evidence), major bleeding (OR 0.91, 95% CI 0.42 to 1.97; 4 studies; N = 583; low-quality evidence) or all-cause mortality (OR 1.74, 95% CI 0.67 to 4.51; 8 studies; N = 972; low-quality evidence). There were no episodes of asymptomatic VTE occurring within three months of the commencement of treatment.When comparing subcutaneous UFH versus LMWH, there was no difference in the incidence of recurrent VTE at three months (OR 1.01, 95% CI 0.63 to 1.63; 5 studies; N = 2156; low-quality evidence), recurrent DVT at three months (OR 1.38, 95% CI 0.73 to 2.63; 3 studies; N = 1566; low-quality evidence), PE (OR 0.84, 95% CI 0.36 to 1.96; 5 studies, N = 1819; low-quality evidence), VTE-related mortality (OR 0.53, 95% CI 0.17 to 1.67; 8 studies; N = 2469; low-quality evidence), major bleeding (OR 0.72, 95% CI 0.43 to 1.20; 5 studies; N = 2300; low-quality evidence) or all-cause mortality (OR 0.73, 95% CI 0.50 to 1.07; 7 studies; N = 2272; low-quality evidence). There were no episodes of asymptomatic VTE occurring within three months of the commencement of treatment. There is no evidence of a difference between subcutaneous versus intravenous UFH for preventing VTE recurrence, VTE-related or all-cause mortality, and major bleeding. According to GRADE criteria, the quality of the evidence was low. There is also no evidence of a difference between subcutaneous UFH and LMWH for preventing VTE recurrence, VTE-related or all-cause mortality or major bleeding.

Use of systemic low-dose unfractionated heparin in microvascular head and neck reconstruction: Influence in free-flap outcomes

Background: Intravenous heparin administration is used to prevent thrombosis in free-flap transfer. However, it is unknown whether the use of heparin affects free-flap survival. The purpose of this study is to investigate the effect of heparin in free flap transfer. Methods: Two hundred and six patients who received ablative surgery for head and neck cancer were classified into three groups. Group A received ablative surgery, neck dissection, and free-flap reconstruction, and postoperatively they were administered continuous intravenous unfractionated heparin (5000–10 000 units/day) until postoperative day 7 (POD7); group B received the same procedures as group A but without heparin; group C received only ablative surgery and neck dissection without heparin. As indicators of coagulation time, the prothrombin time-international normalised ratio (PT-INR) and the activated partial thromboplastin time (APTT) were measured, before surgery and on POD1, 3, and 7. Flap failure, bleeding, haematoma formation, re-exploration, and thromboembolic events were recorded. Results: The PT-INR and APTT were 1.3–1.5-times longer in group A (p < 0.01), and 1.3-times longer (p < 0.01) in group B. The PT-INR and APTT were higher in groups A and B than C (p < 0.01). The free-flap success rate was not affected. Only the incidence of haematoma was increased in group A (p = 0.04). Conclusion: Heparin increased the haematoma formation, but did not change the incidence of free-flap failure. Thus, the intravenous low-dose heparin use does not affect microvascular flap survival.

Establishing the heparin therapeutic range using aPTT and anti-Xa measurements for monitoring unfractionated heparin therapy.

BackgroundUnfractionated heparin (UFH) has unstable pharmacokinetics and requires close monitoring. The activated partial thromboplastin time (aPTT) test has been used to monitor UFH therapy for decades in Korea, but its results can be affected by numerous variables. We established an aPTT heparin therapeutic range (HTR) corresponding to therapeutic anti-Xa levels for continuous intravenous UFH administration, and used appropriate monitoring to determine if an adequate dose of UFH was applied.MethodsA total of 134 ex vivo samples were obtained from 71 patients with a variety of thromboembolisms. All patients received intravenous UFH therapy and were enrolled from June to September 2015 at Gyeongsang National University Hospital. All laboratory protocols were in accordance with the Clinical and Laboratory Standards Institute guidelines and the College of American Pathologist requirements for aPTT HTR.ResultsAn aPTT range of 87.1 sec to 128.7 sec corresponded to anti-Xa levels of 0.3 IU/mL to 0.7 IU/mL for HTR under our laboratory conditions. Based on their anti-Xa levels, blood specimen distribution were as follows: less than 0.3 IU/mL, 65.7%; 0.3–0.7 IU/mL (therapeutic range), 33.6%; and more than 0.7 IU/mL, 0.7%. No evidence of recurring thromboembolism was observed.ConclusionUsing the conventional aPTT target range may lead to inappropriate dosing of UFH. Transitioning from the aPTT test to the anti-Xa assay is required to avoid the laborious validation of the aPTT HTR test, even though the anti-Xa assay is more expensive.

A Marantic Endocarditis Complicating a Metastatic Gastric Adenocarcinoma Initially Resistant to Low-molecular Weight Heparin: A Case Report

Background: Marantic endocarditis is a rare paraneoplastic syndrome which results from an hypercoagulate state. It can be associated with several tumors, particularly gastric cancer, and histology of adenocarcinoma. Mucines secreted by adenocarcinoma contribute to the activation of the coagulation pathway. Case presentation: We present the case of a patient with a marantic endocarditis complicating a metastatic gastric adenocarcinoma. He was hospitalised for a thoracic pain. At the physical examination, we found swelling, redness, and warmth of the right lower limb, suspected for a deep vein thrombosis that was confirmed at the echo doppler ultrasound. CT scan documented a severe bilateral pulmonary embolism, a splenic infarction, and multiple liver metastases. Laboratory tests were normal. Despite a Low-Molecular Weight Heparin (LMWH) treatment, the patient presented a cerebral stroke, confirmed at the MRI. Trans-thoracic echocardiography found a small vegetation of the mobile end of the mitral valve with a normal left ventricular contractile function. LMWH was switched by continuous intravenous Unfractionated Heparin (UFH). PET scan showed multiple liver metastases and a pathological gastric hypermetabolism. Liver biopsy confirmed a metastasis of a HER-2 negative gastric adenocarcinoma. Because of the stop of heparin treatment during this procedure, the patient presented a new brain stroke. A systemic palliative chemotherapy was started by FOLFOX-4 regimen and it is now ongoing. Conclusion: The particularity of this case relies on the impossibility to initially switch UFH by another anticoagulant treatment. Chemotherapy represents the only possibility to decrease mucine production and thrombi formation.

Pulmonary thromboembolism in lung surgery: use of unfractionated heparin

While thoracic surgeons occasionally encounter pulmonary thromboembolism, the use of unfractionated heparin may cause adverse effects. We assessed a series of 323 consecutive pulmonary operations performed during 4 years from 2008 to 2011. All patients were given elastic stockings and intermittent pneumatic compression. During the first 2 years (2008-2009), none of the 169 patients received unfractionated heparin. In the second 2-year period (2010-2011), 135/154 patients received subcutaneous unfractionated heparin, either 5000 units (n = 37) or 2500 units (n = 93) twice daily for 3 days, or continuous intravenous unfractionated heparin (n = 5). The epidural catheters were withdrawn 6 h or more after unfractionated heparin use. Among patients without postoperative unfractionated heparin, 8 (42.1%) had a bleeding risk and 5 (26.3%) had limited operative time. One (0.6%) patient developed pulmonary thromboembolism during 2008-2009, but none had this complication during 2010-2011. The adverse outcome of intrathoracic bleeding occurred in one (2.7%) of the patients given 5000 units of unfractionated heparin, but no epidural hematomas occurred in these patients. Patients undergoing thoracic surgery at low risk of bleeding may receive unfractionated heparin to prevent pulmonary thromboembolism while avoiding epidural complications.

High-dose unfractionated heparin therapy in a pregnant patient with antiphospholipid syndrome: a case report

A case of a 37-year-old pregnant patient with antiphospholipid syndrome (APS), who has a medical history of both thrombosis and recurrent fetal loss, is presented. She was treated with predonisolone and fixed-dose unfractionated heparin (UFH) infusion, followed by plasmaphereses and fixed-dose low-molecular-weight heparin infusion during her fourth pregnancy. Unfortunately, this treatment did not have beneficial effects, resulting in intrauterine growth restriction and finally neonatal death. Continuous intravenous UFH infusion and low-dose aspirin were administrated under the monitoring of the activated partial thromboplastin time to achieve a target level of 120 s during her fifth pregnancy. A healthy baby weighing 1818 g at birth was delivered by Cesarean section at the 34th week of pregnancy. High-dose UFH infusion may be considered to be one of the preferable options to manage pregnant patients with refractory APS.

Incidence and risk factors of early thromboembolic events after mechanical heart valve replacement in patients treated with intravenous unfractionated heparin

Objective:To evaluate the incidence and risk factors, including timing and intensity of anticoagulation, of early thromboembolic events (TE) after mechanical heart valve replacement (MHVR) in patients treated by intravenous unfractionated...

Continuous Intravenous Heparin Infusion Prevents Peri-operative Thromboembolic Events in Bariatric Surgery Patients

The pharmacokinetics of subcutaneous heparin administration in the obese patient are unpredictable. Peak levels are slowly reached and the effects are not rapidly reversible. Low-dose, continuous, intravenous heparin is easily reversed, is more efficacious and is cost-effective. From November 2000 until July 2005, 822 consecutive patients were administered continuous intravenous unfractionated heparin at 400 U/hr (9,600 U/day) starting in the preoperative holding area and maintained until discharge. All clinically significant events were documented. 634 laparoscopic gastric bypass, 10 revisions and 188 Lap-Band procedures were performed. The mean age was 43+/-11 years (15-74) and mean BMI was 45.2+/-7.1 (30-86). There was only one (0.12%) clinically evident thromboembolic event in the entire cohort (after a gastric bypass). Anti-Xa levels and prothrombin time were followed in a group of 40 patients and were found to be normal in all. Bleeding that required transfusion occurred in 1.3% of patients. In 41 patients (5%), heparin therapy was terminated or temporarily held due to need for extensive adhesiolysis or acute drop in hematocrit, with-or-without other evidence of postoperative bleeding. Average estimated blood loss during surgery was 36 cc (5-500 cc). One patient was inadvertently administered excessive doses of heparin due to a pump error without significant sequelae. Continuous low-dose intravenous heparin therapy is associated with an extremely low incidence of thromboembolic events and a low risk for perioperative hemorrhage. Intravenous heparin also has the benefits of being inexpensive and rapidly reversible.

Tratamiento del tromboembolismo pulmonar agudo con heparina de bajo peso molecular subcutánea: Comparación con heparina no fracionada intravenosa

Low-molecular-weight heparins have been demonstrated at least as useful as unfractionated heparin (UFH) in the treatment of venous thromboembolic disease. Our aim was to know the effectivity and security of subcutaneous enoxaparin in the treatment of acute pulmonary embolism. We compared the effectivity and security of two doses daily, subcutaneous injected enoxaparin adjusted to body weight, and standard treatment with continuous intravenous UFH, determining the rate of major bleeding, in-hospital death and recurrent venous thromboembolic disease in long-term follow up. Massive pulmonary thromboembolism was defined as thrombotic material seen in main pulmonary arteries. Thirty eight patients were treated with UFH (Mean age 72 SD 9 years, male 58%, massive pulmonary thromboembolism 24%) and 65 patients were treated with subcutaneous enoxaparin (Mean age 71 SD 12 years, male 52%, massive pulmonary thromboembolism 49%). Major bleeding rate was 8% in UHF group and 3% in enoxaparin group (Difference 37%, 95% Confidence interval -0.16 to 0.06, p=0.21). In-hospital death rate was 8% in UHF group and 1.5% in enoxaparin group (Difference 25%, 95% Confidence interval -0.17 to 0.04, p=0.11). Recurrent thromboembolism rate was 44% in UFH group and 13% in enoxaparin group (Difference 30%, 95% Confidence interval -0.60 to -0.02, p=0.01). Our findings demonstrate that treatment of acute pulmonary thromboembolism with low-molecular-heparin is effective and safe, even in massive pulmonary embolism.

Treat DVT with low molecular weight heparin.

Each year, deep vein thrombosis (DVT) affects two million Americans, and pulmonary embolism (PE) affects 600,000. Traditional treatment requires hospitalization to receive continuous intravenous unfractionated heparin (UFH), which has substantial pharmacokinetic limitations. Low molecular weight heparins have overcome many of these limitations, resulting in a predictable anticoagulant response without the need for laboratory monitoring or dosage adjustment.

Enoxaparin monotherapy without oral anticoagulation to treat acute symptomatic pulmonary embolism

Conventional anticoagulation for symptomatic pulmonary embolism consists of continuous intravenous unfractionated heparin as a "bridge" to oral anticoagulation. This strategy requires 5 days or more of intravenous heparin while oral vitamin K antagonists gradually achieve a therapeutic effect. Oral vitamin K antagonists require frequent blood testing to optimize dosing, and their interactions with other medications and foods make regulation difficult. Therefore we tested a different approach to therapy: long-term enoxaparin monotherapy. We randomized 60 symptomatic pulmonary embolism patients in a 2:1 ratio to 90 days of enoxaparin as monotherapy without warfarin (N=40) or to intravenous unfractionated heparin as a "bridge" to warfarin, target INR 2.0-3.0 (N=20). Enoxaparin patients received 1 mg/kg twice daily for 14 days during the acute phase followed by randomized assignment during the chronic phase to 1.0 mg/kg vs. 1.5 mg/kg once daily. In an intention-to-treat analysis, 3 of the 40 enoxaparin patients developed recurrent venous thromboembolism compared with 0 of 20 standard therapy patients (p = 0.54). One of the 40 enoxaparin patients had a major hemorrhagic complication compared with 2 of the 20 standard therapy patients (p = 0.26). Median hospital length of stay was shorter with enoxaparin compared to standard therapy (4 vs. 6 days) (p = 0.001). Following our study we can conclude that extended 3-month treatment with enoxaparin as monotherapy for symptomatic, acute pulmonary embolism is feasible and warrants further study in a large clinical trial.

Initiation of anticoagulation after cardiac surgery: a prospective cohort study of efficacy, safety, and cost with low molecular weight heparin bridging in lieu of continuous intravenous unfractionated heparin

Initiation of anticoagulation after cardiac surgery: a prospective cohort study of efficacy, safety, and cost with low molecular weight heparin bridging in lieu of continuous intravenous unfractionated heparin

Frequency of major hemorrhage in patients treated with unfractionated intravenous heparin for deep venous thrombosis or pulmonary embolism: a study in routine clinical practice.

The rate of major hemorrhage during the initial treatment with unfractionated heparin (UFH) in patients with deep venous thrombosis (DVT) and pulmonary embolism (PE) in routine clinical practice is understudied. In recent clinical trials an overall average of 3.8% was reported. However, the incidence of this complication in routine patient care might be higher owing to less strict patient selection and lack of standardization in the administration of heparin. We have determined major bleeding rates during heparin treatment for DVT or PE in routine practice and compared these rates with data from clinical trials. Data on the occurrence of major hemorrhage were retrieved according to strict criteria from the records of patients who had received continuous intravenous UFH therapy to treat objectively documented DVT or PE in 3 hospitals. After exclusion of 29 patients because of lack of objective diagnosis of DVT or PE and 25 patients because of initial treatment with low-molecular-weight heparin, 424 consecutive patients were available for detailed analysis. Among them, 17 patients (4.0%; 95% confidence interval, 2.1%-5.9%) experienced major hemorrhage during UFH treatment, which in most patients occurred at the end of planned heparin therapy; one of the hemorrhages was fatal. Six patients (1.4%; 95% confidence interval, 0.3%-2.5%) developed clinically suspected recurrent venous thromboembolism (fatal in 1 case) during UFH treatment or within 7 days' cessation. Administration of continuous intravenous UFH in patients with DVT or PE in routine clinical practice leads to a major bleeding rate of 4.0%. This rate is comparable to the rate of major bleeding in patients who received UFH in clinical trials. Our findings are relevant to the discussion of major bleeding rates in patients with DVT and PE treated in daily clinical practice with subcutaneous low-molecular-weight heparin and newer antithrombotic drugs.

Optimal Dosing of Subcutaneous Unfractionated Heparin for the Treatment of Deep Vein Thrombosis

Twice-daily, inpatient, subcutaneous unfractionated heparin is at least as effective and safe as continuous intravenous unfractionated heparin for the treatment of acute deep vein thrombosis. Subcutaneous unfractionated heparin therefore may be suitable for outpatient treatment of deep vein thrombosis. The purpose of this study was to develop a dosing nomogram for a dose each 12 hours (2 doses per day) 12-hourly subcutaneous unfractionated heparin that is suitable for outpatient treatment of acute deep vein thrombosis. A cohort study was performed in patients with acute deep vein thrombosis in two phases. In both phases, the first subcutaneous loading dose of unfractionated heparin was 317 U/kg, and the second dose was 231 U/kg. The activated partial thromboplastin time was measured daily, 6 hours after the morning injection, and subsequent doses of unfractionated heparin were adjusted according to a nomogram, which was modified for phase II. Warfarin was started with unfractionated heparin. In phase I (14 outpatients), activated partial thromboplastin time results were frequently subtherapeutic (9:14) the day after starting unfractionated heparin (day 1), and were frequently supratherapeutic (27:40) after the first 2 days of unfractionated heparin therapy. In phase II (21 patients), to explain the frequently subtherapeutic activated partial thromboplastin time results that were obtained on day 1, the activated partial thromboplastin time results were measured after the initial loading dose. Mean activated partial thromboplastin time results of 86 and 61 seconds were obtained 6 and 12 hours after this dose, suggesting that 317 U/kg is a suitable subcutaneous loading dose. In contrast to phase I, in phase II, unfractionated heparin dose was not increased on day 1 in response to a low activated partial thromboplastin time result. This reduced the frequency of supratherapeutic activated partial thromboplastin time results during the early days of therapy without increasing the frequency of subtherapeutic results. Warfarin therapy had a substantal effect on the activated partial thromboplastin time that appeared to account for a high frequency of supratherapeutic results during the later days of unfractionated heparin therapy; the activated partial thromboplastin time increased by 20 seconds (95% CI, 14–27 seconds) with each increase in the International Normalized Ratio of 1.0. We had limited success at developing a dosing nomogram for subcutaneous unfractionated heparin that reliably achieved activated partial thromboplastin time results within the therapeutic range. However, as oral anticoagulants directly increased activated partial thromboplastin time results, we suggest that adjusting unfractionated heparin dose to achieve prespecified activated partial thromboplastin time results may not be appropriate in patients who are receiving concomitant warfarin therapy.

Deep venous thrombosis: early discharge strategies and outpatient management.

Conventional management of acute deep venous thrombosis (DVT) consists of initiating continuous infusion intravenous unfractionated heparin (UFH) for 5 days in the hospital as well as warfarin. Low-molecular-weight heparins (LMWHs) appear to confer similar protection against recurrent DVT compared with UFH but exhibit prolonged bioavailability; increased ease of dosing, and fewer side effects. The advent of LMWH has resulted in increased numbers of patients undergoing initial management of acute DVT with only several days of hospitalization. While 3-month follow-up studies with LMWH demonstrate similar efficacy and safety to UFH, longer term experience with these new agents is necessary to determine their optimal use and safety. We suggest a system for triage in the initial management of DVT patients for: (1) complete outpatient management with LMWH, or (2) short-term hospitalization for initiation of LMWH, or (3) 5-day hospitalization for treatment with UFH. A review of DVT management with LMWH and algorithms for each of these pathways are provided.