Heparin Treatment of Deep Vein Thrombosis

Hepatotoxicity With Elevated Bilirubin Secondary to Prophylactic Doses of Unfractionated Heparin: A Case Report and Review of Heparin-Induced Hepatotoxicity

Objective: To report a case of heparin-induced hepatotoxicity in a patient without prior liver dysfunction who received prophylactic doses of unfractionated heparin (UFH). Case Summary: A 70-year-old man with no prior liver dysfunction was admitted to the hospital for presyncope, secondary to dehydration, and new-onset congestive heart failure. Prophylactic UFH was initiated for deep vein thrombosis prophylaxis. Within 2 days, he developed increases in aspartate aminotransferase and alanine aminotransferase. By day 4, aspartate aminotransferase and alanine aminotransferase were greater than 5 and 9 times the upper limit of normal, respectively. Alkaline phosphatase and bilirubin were markedly elevated as well. UFH was discontinued on day 4, and liver enzymes subsequently normalized. Discussion: Hepatotoxicity, defined as increases in transaminases greater than 3 times the upper limit of normal, is relatively rare-estimated to occur in only 5% of those receiving therapy with UFH. Concurrent elevations in bilirubin have rarely been reported. Enzymes typically begin to rise after 4 to 5 days of UFH use and return to normal within 2 weeks of discontinuation. Previously published case reports of heparin-induced hepatotoxicity have occurred with therapeutic doses of either UFH or low-molecular-weight heparins. Conclusions: Heparin-induced hepatotoxicity may occur more rapidly than previously described, and even with the use of prophylactic doses of UFH. Given their widespread use, it is important for clinicians to consider heparins in their differential as a potential cause of hepatotoxicity especially in patients without underlying hepatic disease.

Recurrence and Late Sequelae after First-Time Deep Vein Thrombosis: Relationship to Initial Signs

Objective:

To investigate the relation between initial symptoms and long-term sequelae in first-time deep venous thrombosis (DVT).

Design:

Follow-up study of patients 6 years after an episode of suspected symptomatic DVT.

Setting:

Vascular laboratory, University Hospital of Lund.

Patients:

66 patients, 19 with femoral DVT, 20 with calf DVT and 27 with normal phlebograms at initial investigation.

Main outcome measures:

Symptoms and signs of chronic venous insufficiency (CVI), foot volumetry and measurement of plasminogen activator inhibitor 1 (PAI-1) activity. Initial clinical signs and results at phlebography were compared with findings at follow-up.

Results:

Of patients with DVT, 11 (28%) had been treated for a recurrent DVT during follow-up. No relation was found between initial signs of DVT and late signs of CVI. Patients with DVT had significantly more signs of CVI but symptoms did not differ between the groups. Mean levels of PAI-1 activity were similar in the three groups, and patients with recurrent DVT did not differ. Refilling flow was related to the clinical CVI-score, and expelled volume was inversely related to the extension of DVT at phlebography.

Conclusion:

The recurrence rate is high in first-time DVT, but symptoms are mostly mild as long as after 6 years. There is a poor correlation between symptoms of CVI and objective findings. The late development of CVI cannot be predicted from the clinical signs in the acute phase. Levels of PAI-1 do not correlate with the degree of CVI.

The effects of heparins on the liver: application of mechanistic serum biomarkers in a randomized study in healthy volunteers

Heparins have been reported to cause elevations in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) but have not been associated with clinically significant liver injury. The mechanisms underlying these benign laboratory abnormalities are unknown. Forty-eight healthy men were randomized to receive subcutaneous injections of unfractionated heparin (UFH; 150 U/kg), enoxaparin sodium (1 mg/kg), dalteparin sodium (120 IU/kg), or adomiparin sodium (125 IU/kg; a novel heparin) every 12 h for 4.5 days. Asymptomatic elevations in serum ALT or AST were observed in >90% of the subjects. Elevations were also observed in the levels of serum sorbitol dehydrogenase (SDH), glutamate dehydrogenase (GLDH), miR-122, high-mobility group box-1 protein (including the acetylated form), full-length keratin 18, and DNA. Keratin 18 fragments, which are apoptosis biomarkers, were not detected. Biomarker profiles did not differ significantly across heparin treatments. We conclude that heparins as a class cause self-limited and mild hepatocyte necrosis with secondary activation of an innate immune response.

The clinical picture of deep vein thrombosis correlated to the frequency of pulmonary embolism

Pain and swelling of the leg have been studied in 27 patients with deep vein thrombosis (DVT). Twenty-three of them were also examined for pulmonary embolism (PE) after one week of heparin treatment. Scoring systems were constructed to quantitate pain, size of DVT and PE. A ratio between swelling and pain (S/P ratio) was calculated for each patient. Actual size of the DVT, as estimated with venous phlebography, was correlated to swelling (rs = 0.51, p less than 0.01), S/P ratio (rs = 0.53, p less than 0.01) and PE (rs= 0.57, p less than 0.01). DVTs with not pain at all or just tenderness on palpation were more often associated with PE (p less than 0.05) and elevated blood pressure (p = 0.02) than DVTs with pain on walking. A free floating proximal end of DVT proved unreliable for predicting PE. It is concluded that the risk of developing PE depends not only on DVT size, but also on factors related to pain.

Antithrombotic therapy for venous thromboembolic disease: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy

This chapter about antithrombotic therapy for venous thromboembolic disease is part of the seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following: for patients with objectively confirmed deep vein thrombosis (DVT), we recommend short-term treatment with subcutaneous (SC) low molecular weight heparin (LMWH) or, alternatively, IV unfractionated heparin (UFH) [both Grade 1A]. For patients with a high clinical suspicion of DVT, we recommend treatment with anticoagulants while awaiting the outcome of diagnostic tests (Grade 1C+). In acute DVT, we recommend initial treatment with LMWH or UFH for at least 5 days (Grade 1C), initiation of vitamin K antagonist (VKA) together with LMWH or UFH on the first treatment day, and discontinuation of heparin when the international normalized ratio (INR) is stable and > 2.0 (Grade 1A). For the duration and intensity of treatment for acute DVT of the leg, the recommendations include the following: for patients with a first episode of DVT secondary to a transient (reversible) risk factor, we recommend long-term treatment with a VKA for 3 months over treatment for shorter periods (Grade 1A). For patients with a first episode of idiopathic DVT, we recommend treatment with a VKA for at least 6 to 12 months (Grade 1A). We recommend that the dose of VKA be adjusted to maintain a target INR of 2.5 (INR range, 2.0 to 3.0) for all treatment durations (Grade 1A). We recommend against high-intensity VKA therapy (INR range, 3.1 to 4.0) [Grade 1A] and against low-intensity therapy (INR range, 1.5 to 1.9) compared to INR range of 2.0 to 3.0 (Grade 1A). For the prevention of the postthrombotic syndrome, we recommend the use of an elastic compression stocking (Grade 1A). For patients with objectively confirmed nonmassive PE, we recommend acute treatment with SC LMWH or, alternatively, IV UFH (both Grade 1A). For most patients with pulmonary embolism (PE), we recommend clinicians not use systemic thrombolytic therapy (Grade 1A). For the duration and intensity of treatment for PE, the recommendations are similar to those for DVT.

Hemorrhagic Complications of Anticoagulant Treatment

This chapter about hemorrhagic complications of anticoagulant treatment is part of the seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Bleeding is the major complication of anticoagulant therapy. The criteria for defining the severity of bleeding varies considerably between studies, accounting in part for the variation in the rates of bleeding reported. The major determinants of vitamin K antagonist-induced bleeding are the intensity of the anticoagulant effect, underlying patient characteristics, and the length of therapy. There is good evidence that vitamin K antagonist therapy, targeted international normalized ratio (INR) of 2.5 (range, 2.0 to 3.0), is associated with a lower risk of bleeding than therapy targeted at an INR > 3.0. The risk of bleeding associated with IV unfractionated heparin (UFH) in patients with acute venous thromboembolism (VTE) is < 3% in recent trials. This bleeding risk may increase with increasing heparin dosages and age (> 70 years). Low molecular weight heparin (LMWH) is associated with less major bleeding compared with UFH in acute VTE. UFH and LMWH are not associated with an increase in major bleeding in ischemic coronary syndromes, but are associated with an increase in major bleeding in ischemic stroke. Information on bleeding associated with the newer generation of antithrombotic agents has begun to emerge. In terms of treatment decision making for anticoagulant therapy, bleeding risk cannot be considered alone, ie, the potential decrease in thromboembolism must be balanced against the potential increased bleeding risk.

Hemorrhagic complications of anticoagulant treatment

Bleeding is the major complication of anticoagulant therapy. The criteria for defining the severity of bleeding varied considerably between studies, accounting in part for the variation in the rates of bleeding reported. Since the last review, there have been several meta-analyses published on the rates of major bleeding in trials of anticoagulants for atrial fibrillation and ischemic heart disease. The major determinants of oral anticoagulant-induced bleeding are the intensity of the anticoagulant effect, underlying patient characteristics, and the length of therapy. There is good evidence that low-intensity oral anticoagulant therapy (targeted INR of 2.5; range, 2.0 to 3.0) is associated with a lower risk of bleeding than therapy targeted at a higher intensity. Lower-intensity regimens (INR < 2.0) are associated with an even smaller increase in major bleeding. In terms of treatment decision making for anticoagulant therapy, bleeding risk cannot be considered alone, ie, the potential decrease in thromboembolism must be balanced against the potential increased bleeding risk. The risk of bleeding associated with IV heparin in patients with acute venous thromboembolism is < 3% in recent trials. There is some evidence to suggest that this bleeding risk increases with the heparin dosage and age (> 70 years). LMW heparin is not associated with increased major bleeding compared with standard heparin in acute venous thromboembolism. Standard heparin and LMW heparin are not associated with an increase in major bleeding in ischemic coronary syndromes, but are associated with an increase in major bleeding in ischemic stroke.

Phenytoin as a possible cause of acetaminophen hepatotoxicity: case report and review of the literature

A 55-year-old woman was hospitalized for treatment of community-acquired pneumonia. Unexplained, moderate elevations in hepatic transaminase and enzyme levels prompted review of her drug regimen. She had taken acetaminophen 1,300-6,200 mg/day during the hospitalization. She also received phenytoin for posttraumatic seizures. Acetaminophen was discontinued, and the patient's liver chemistries returned to normal within 2 weeks of discharge. Acetaminophen is metabolized in part by cytochrome P450 (CYP) 2E1, and inducers of CYP2E1 are known to predispose patients to acetaminophen-related hepatotoxicity. Phenytoin induces CYP2C and CYP3A4 isoforms, but not CYP2E1. The literature suggests, however, that CYP3A4 may participate in acetaminophen metabolism to a greater extent than previously realized, and induction of this isoform may predispose patients to acetaminophen-induced hepatotoxicity.

The use of heparin in patients in whom a pulmonary embolism is suspected after total hip arthroplasty

BACKGROUND

The morbidity and mortality associated with pulmonary embolism are well known, as is the benefit of the use of heparin in patients who have a pulmonary embolism. However, the patterns of heparin use as well as its undesirable effects, especially in patients who have recently had a total hip arthroplasty, have been less well studied. Thus, concern arises regarding the use of heparin in patients who have no firm evidence of a pulmonary embolism. The purpose of the current study was to track the use of heparin and associated orthopaedic complications in patients in whom a pulmonary embolism was suspected after a total hip arthroplasty.

METHODS

The records of 150 patients in whom a pulmonary embolism had been suspected after a total hip arthroplasty were reviewed retrospectively. The rates of individual complications (such as stroke, infection, and hematoma) and those of groups of complications (such as medical complications, orthopaedic complications, and all complications combined) were recorded and then were stratified according to the treatment (with or without heparin), the presence or absence of pulmonary embolism, and other variables.

RESULTS

Thirty-two (47 percent) of sixty-eight patients who were managed with heparin had complications compared with sixteen (20 percent) of eighty-two patients who were not thus managed (p = 0.0006). Specifically, patients who were managed with heparin were more likely to have gastrointestinal bleeding, hematological complications, a loose prosthesis, a hematoma, or an early revision arthroplasty (p<0.05 for all). With the numbers available, the use of heparin was not found to be significantly associated with an increased risk of death, stroke, or infection at the site of the prosthesis. Interestingly, thirty-one (31 percent) of ninety-nine patients who had ventilation-perfusion scans that demonstrated normal findings or findings indicating a low probability of pulmonary embolism were given heparin before the diagnosis of a pulmonary embolism was excluded, and sixteen (52 percent) of these thirty-one had complications.

CONCLUSIONS

Given this risk profile, we advise against the use of heparin before the diagnosis of pulmonary embolism is established in patients who have had a total hip arthroplasty. This recommendation is supported by algorithms, in widely read medical texts, pertaining to the use of heparin in patients in whom a pulmonary embolism is suspected.

A decision analysis of streptokinase plus heparin as compared with heparin alone for deep-vein thrombosis

BACKGROUND

It is uncertain whether patients with proximal deep-vein thrombosis should be treated with streptokinase followed by intravenous heparin or with intravenous heparin alone. Published reports indicate that streptokinase plus heparin increases the risk of bleeding, including central nervous system bleeding and death, but decreases the risk of postphlebitic syndrome. Previous recommendations regarding these treatments have not considered patients' preferences or the values they attach to the possible outcomes of therapy.

METHODS

We used decision analysis to combine published estimates of the probabilities of various adverse outcomes of treatment (bleeding, pulmonary embolism, postphlebitic syndrome, and death) with the values patients placed on these outcomes. We questioned 36 patients about the values they attached to each outcome. Sixteen patients had had deep-vein thrombosis, and 20 had not.

RESULTS

By the values they attached to the outcomes, all 36 patients indicated that they were unwilling to accept an increased risk of death to avoid postphlebitic syndrome. According to the decision analysis, heparin alone was the better treatment for all 36 patients. As compared with streptokinase plus heparin, heparin alone provided 29 days of additional life expectancy over the predicted life expectancy of 20 years. Although the difference between the two treatments was small, heparin alone remained the better treatment in sensitivity analyses that examined the reasonable ranges of probabilities of the clinical outcomes.

CONCLUSIONS

The values patients placed on the outcomes of treatment for deep-vein thrombosis support the use of heparin alone over the combined use of streptokinase and heparin.

Anticoagulant-related bleeding: clinical epidemiology, prediction, and prevention

OBJECTIVE

To review (1) the clinical epidemiology of bleeding during anticoagulant therapy with heparin or warfarin, (2) data useful in estimating the risk for bleeding in individual patients, and (3) the efficacy of methods for its prevention.

METHODS

Relevant literature was identified by a computerized search of the Medline database and by review of the bibliographies of original and review articles. Studies were classified according to their design. Estimates of the risk for bleeding during anticoagulant therapy, compared with the risk without therapy, were obtained from randomized trials. Estimates of the frequency of bleeding during the course of anticoagulant therapy and information about risk factors for bleeding were obtained primarily from longitudinal studies of inception cohorts of patients followed from the start of therapy.

MAIN RESULTS

The average daily frequencies of fatal, major, and major or minor bleeding during heparin therapy were 0.05%, 0.8%, and 2.0%, respectively; these frequencies are approximately twice those expected without heparin therapy. The average annual frequencies of fatal, major, and major or minor bleeding during warfarin therapy were 0.6%, 3.0%, and 9.6%, respectively; these frequencies are approximately five times those expected without warfarin therapy. The risk for anticoagulant-related bleeding is highest at the start of therapy: during warfarin therapy, the risk for major bleeding during the first month of therapy is approximately 10 times the risk after the first year of therapy. An individual patient's risk for major anticoagulant-related bleeding can be estimated on the basis of specific risk factors such as the intensity of the anticoagulant effect achieved and the presence of serious comorbid diseases, especially cerebrovascular, kidney, heart, and liver disease; older age and concurrent medicines may also be independent risk factors. Major bleeding most often affects the gastrointestinal tract, soft tissues, and urinary tract. Diagnostic evaluation of gastrointestinal bleeding and gross hematuria leads to identification of previously unknown lesions in approximately one-third of cases, even when the prothrombin time is elevated. Intracranial bleeding is rare, but it is frequently fatal. The frequency of bleeding during warfarin therapy is reduced by less intense therapy achieving a prothrombin time with an International Normalized Ratio of 2.0 to 3.0, which is efficacious for most indications.

CONCLUSION

Anticoagulant-related bleeding is common and often serious. The risk for bleeding can be estimated in an individual patient, giving the primary physician a quantitative basis for weighing the risks and benefits of therapy and for optimizing patient management. The frequency of anticoagulant-related bleeding is reduced by less intense warfarin therapy. Future studies should evaluate new approaches to management that may further reduce complications while maintaining efficacy.

Heparin and the in-hospital management of deep venous thrombosis: cost considerations

Numerous protocols for the treatment of deep venous thrombosis (DVT) with heparin have been recommended. In the past, physicians rarely considered costs in their decision to use a particular protocol; however, the recent introduction of the diagnosis-related groups (DRGs) and other cost-reduction measures has imposed financial limitations on the practice of medicine and surgery. To determine how the cost of treatment for DVT at the Mayo Clinic might be affected by the use of alternative heparin protocols, we conducted a two-stage study. In the first part, charts of 40 patients with uncomplicated DVT were analyzed retrospectively to determine an "average" Mayo Clinic heparin protocol for DVT. In the second part, this "average" protocol was compared with four other currently advocated protocols, and the cost of using each protocol at the Mayo Clinic was estimated. These protocols differed from the Mayo Clinic protocol with respect to method and route of heparin administration, frequency of monitoring anticoagulation, and duration of heparin treatment. This analysis revealed that the average charges resulting from treatment of DVT at the Mayo Clinic exceeded the corresponding DRG payment and that the cost of treatment varied substantially with the protocol used (a difference of more than $2,000 between two of the protocols analyzed). A review of the literature provided little evidence to suggest that the alternative protocols were not equally effective. Therefore, we concluded that measures such as shortening the duration of heparin therapy, administration of heparin by the subcutaneous route, and minimal monitoring of anticoagulation (in patients with a low risk of bleeding) can substantially reduce the cost of treating DVT and may be no less effective than other protocols for heparinization.(ABSTRACT TRUNCATED AT 250 WORDS)