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PubMed2000

Fixed dose subcutaneous low molecular weight heparins versus adjusted dose unfractionated heparin for venous thromboembolism.

BACKGROUND: Low molecular weight heparins have been shown to be effective and safe for prevention of venous thromboembolism. There is accumulating evidence that these new anticoagulants are also effective and safe for treatment of venous thromboembolism. OBJECTIVES: The objective of this review was to determine the effect of fixed-dose, subcutaneous low molecular weight heparins compared with adjusted-dose, intravenous or subcutaneous, unfractionated heparin for initial treatment of acute deep venous thrombosis or pulmonary embolism. SEARCH STRATEGY: Trials were identified from the Cochrane Peripheral Vascular Diseases Group trials register and LILACS. The reviewers contacted colleagues and representatives of pharmaceutical companies for additional information about trials. SELECTION CRITERIA: Randomised trials comparing fixed-dose, subcutaneous low molecular weight heparin with adjusted-dose, intravenous or subcutaneous, unfractionated heparin in patients with venous thromboembolism. DATA COLLECTION AND ANALYSIS: Two reviewers assessed trials for inclusion and quality, and extracted data independently. MAIN RESULTS: Fourteen studies with a total of 4754 patients were included. By the end of follow up in ten trials, thrombotic complications occurred in 86 (4.3%) of the 1998 patients treated with low molecular weight heparin, compared with 113 (5.6%) of the 2021 patients treated with unfractionated heparin (odds ratio 0.76, 95% confidence interval 0.57 to 1.01). In eight trials a reduction in thrombus size was shown by 60% treated with low molecular weight heparin and 54% treated with unfractionated heparin (odds ratio 0.77, 95% confidence interval 0.61 to 0.97). At the end of the initial treatment period, in all 14 of the trials, major haemorrhages occurred in 30 (1.3%) of the 2353 patients treated with low molecular weight heparin, compared with 51 (2.1%) of the 2401 patients treated with unfractionated heparin (odds ratio 0.60, 95% confidence interval 0.39 to 0.93). By the end of follow up in 11 trials, 135 (6.4%) of the 2108 patients treated with low molecular weight heparin had died, compared with 172 (8.0%) of the 2137 patients treated with unfractionated heparin (odds ratio 0.78, 95% confidence interval 0.62 to 0.99). Five studies with a total of 1636 patients examined proximal (above the knee) thrombosis; 814 treated with low molecular weight heparin and 822 with unfractionated heparin. A sub-analysis of these trials showed statistically significant reductions favouring the action of low molecular weight heparin in three areas: thrombotic complications; major haemorrhages; and overall mortality. By the end of follow up 39 (4. 8%) patients treated with low molecular weight heparin had thrombotic complications, compared with 64 (7.8%) treated with unfractionated heparin (odds ratio 0.60, 95% confidence interval 0. 40 to 0.89). Major haemorrhages occurred in 8 (1.0%) treated with low molecular weight heparin, compared with 68 (8.3%) treated with unfractionated heparin (odds ratio 0.44, 95% confidence interval 0. 21 to 0.95). By the end of follow up, 44 (5.4%) treated with low molecular weight heparin had died, compared with 68 (8.3%) treated with unfractionated heparin (odds ratio 0.64, 95% confidence interval 0.43 to 0.93). REVIEWER'S CONCLUSIONS: Low molecular weight heparin is at least as effective as unfractionated heparin in preventing recurrent venous thromboembolism, and significantly reduces the occurrence of major haemorrhage during initial treatment and overall mortality at the end of follow-up. It can be adopted safely as the standard therapy for deep venous thrombosis, and studies comparing individual low molecular weight heparins are merited.

Heparin↗
PubMed2003

Thromboembolism preceding cancer: a correlation study.

Thromboembolic (TE) events preceding cancer have been observed. Some studies failed to find this correlation. We retrospectively examined the cancer incidence following thromboembolic events in patients at our medical center. Medical records of 183 patients with established thromboembolic events documented in their records were selected and reviewed. Time interval between primary, secondary, and recurrent TE events preceding cancer diagnosis was analyzed. Two hundred age- and sex-matched controls seen during the same period and without any evidence of TE were randomly selected and charts reviewed for malignancy. Cancer occurred after TE in 48 of 183 patients (26.2%). In controls, cancer was diagnosed in 23 (11.5%). This was statistically significant with an odds ratio of 2.736 (1.586, 4.720). In the 64 primary TE patients, the cancer incidence was 37.5%. The 63 patients with recurrent TE had an incidence of 35.4%, and 56 secondary TE patients had an incidence of 27.1%. Time between initial TE and cancer diagnosis was <6 months in 27 (56.3%) patients, between 6 months and 1 year in 12 (25.0%), 1-5 years in 5 (10.4%), and >5 years in 4 (8.3%). Fourteen (31.1%) TE patients presented with metastatic cancer. This study indicates that thromboembolic events are important predictors of cancer. Cancer in this population occurs within a year in the majority of patients. Cancer screening in patients without identifiable risk factors for thrombosis could be helpful for early detection, diagnosis, and management of cancer.

Adult↗
PubMed1996

F-amplitude, left atrial appendage velocity, and thromboembolic risk in nonrheumatic atrial fibrillation. Stroke Prevention in Atrial Fibrillation Investigators.

BACKGROUND: Reduced left atrial appendage velocity (LAAV) has been identified as a marker for thromboembolism in patients with atrial fibrillation. HYPOTHESIS: It was postulated that electrocardiographic (ECG) F-wave amplitude would correlate with LAAV, and inversely with the risk of thromboembolism in patients with atrial fibrillation. METHODS: In all, 53 patients with nonrheumatic (NRAF) and 7 patients with rheumatic (RAF) atrial fibrillation underwent assessment of maximum LAAV, which was correlated to the maximum ECG F-wave voltage from lead V1 (F(max)). In 450 NRAF patients on neither aspirin nor warfarin, the relationship between F(max) and thromboembolic risk was assessed over an average follow-up of 1.3 years. RESULTS: F(max) did not correlate with LAAV (r = 0.2, p = 0.07). Patients with intermittent atrial fibrillation (n = 123) had smaller F(max) amplitude than patients with constant atrial fibrillation (n = 327) (mean 0.73 vs. 0.88 mV-1, p = 0.001). F(max) amplitude was not related to a history of hypertension, systolic blood pressure, duration of NRAF, abnormal transthoracic echocardiographic left ventricular (LV) systolic function or left atrial (LA) diameter. There was a strong trend for increased LV mass being related to smaller F(max) amplitude after adjusting for body surface area (p = 0.06). F(max) amplitude was not correlated with risk of embolic events, including only those events presumed by a panel of case-blinded neurologists to be cardioembolic. CONCLUSIONS: F(max) amplitude in NRAF is smaller in patients with intermittent versus constant AF. It does not correlate with LAAV, LA size, increased LV mass, or systolic dysfunction, hypertension, or risk of embolism. Therefore, F(max) amplitude may not be used as a surrogate for LAAV, or as a measure of thromboembolic risk in NRAF.

Aged↗
PubMed1992

[Perioperative prevention of thromboembolism with standard heparin and low molecular weight heparin, evaluation of postoperative hemorrhage. A double-blind, prospective, randomized and mono-center study].

From October 1987 through June 1988 594 patients admitted to the department of visceral surgery, were included in a prospective, randomized double-blind study dealing with postoperative thromboembolic complications. 5000 I.U. heparin were administered twice daily to one group, the other group received a single dose of low molecular heparin (3000 I.U. anti-Xa) daily. In each group more than 290 patients were included. Diagnostic screening was done using LCCT (Liquid Crystal Contact Thermography) and phlebography. 130 patients had to be excluded from the study. 66 patients because of contra-indication, 54 patients because of administrative failing and 10 patients were excluded by the surgeon himself. There was no significant difference between the two groups concerning thromboembolic complications. However analysis of the patients who were excluded from the study shows an increase of thromboembolic complications. Looking at cases of postoperative haemorrhage we found that there was no significant difference between both groups. Interestingly, even compared to the excluded group, there was no difference. In our study postoperative haemorrhagic complications did not depend on the method of prophylaxis but on the surgeon performing the operation. Should a patient have a contra-indication for administration of thromboembolic prophylaxis, he has to take a certain risk of thrombosis. The fact that prophylaxis was not initiated because of neglect or fear of haemorrhagic complications is not only unforgiveable, but dangerous as well.

Adolescent↗
PubMed1994

Prophylaxis of venous thromboembolism in brain tumor patients.

Thromboembolism is a common problem in patients with brain tumors. Within this population are subpopulations of patients at varying but substantial risk for deep vein thrombosis and pulmonary embolism. Prophylactic strategies can be applied to these various risk groups that will dramatically reduce the incidence of thromboembolism, and these should be applied on a routine basis. The standard prophylactic methods for thromboembolic prophylaxis include mechanical devices (e.g., graduated leg stockings; external pneumatic calf compression) and pharmacological agents (e.g., low dose heparin). In addition, a basic knowledge of low molecular weight heparins and heparinoids is essential because these new agents have a potentially promising role in the prophylaxis of neurological disease in certain patients. The principles concerning the prophylaxis of venous thromboembolic disease in patients with brain tumors are addressed in this review.

Brain Neoplasms↗
PubMed1994

Thromboembolic complications associated with brain tumors.

Thromboembolic complications are the second most common cause of death in hospitalized cancer patients; they are caused by alterations of hemostasis and include hypercoagulable states, acute and chronic disseminated intravascular coagulation, and primary fibrinolysis. The fibrinolytic system is comprised of several serine protease enzymes and their inhibitors and is associated in various biological systems with physiological and pathological events such as tissue development, remodeling, invasiveness, and migratory potentials of both normal and malignant cells. It also plays a key role in the dissolution of fibrin strands. Defective fibrinolysis, which is often associated with the pathogenesis of venous thrombosis and other thromboembolic complications, occurs when the balance is disrupted, resulting in either inhibition or enhancement of fibrinolysis. The association between thromboembolic complications and neoplastic disease has been well-established since Trousseau in 1865 first reported a high incidence of venous thrombosis in a series of patients with gastric carcinoma. In this article, we discuss the factors that have been shown to be associated with thromboembolic complications in patients who harbor brain tumors, namely, hemostatic alterations caused by the tumors themselves or through interactions with neural tissue around the tumors, pre-operative hemostatic alterations in certain patients, and defective fibrinolysis associated with specific tumor types and/or tumor locations.

Brain Neoplasms↗
PubMed1992

Arterial thromboembolic complications of inflammatory bowel disease. Report of three cases.

Extraintestinal manifestations of inflammatory bowel disease are legion and are demonstrated in one-third of those afflicted. In general, they do not mandate surgery. Three patients with active pancolonic ulcerative colitis developed arterial thromboembolic complications prior to surgical treatment. Thromboembolic complications are not fully understood, as is evidenced by the paucity of information in the literature, and only sporadic cases of arterial thromboemboli are found. These have been described primarily in the postsurgical patient. To ascertain whether others have encountered similar cases, a survey form was distributed to members of The American Society of Colon and Rectal Surgeons, yielding an additional 54 patients with thromboembolic complications. Approximately two-thirds were deep venous thromboses and/or pulmonary emboli. Ten patients had cerebrovascular accidents, and eight had arterial emboli. Eleven patients, over 21 percent, suffered multiple events. There were four resultant mortalities. An arterial thromboembolic event in a patient with ulcerative colitis is usually associated with pancolonic disease, has a poor long-term prognosis, and is an indication for colectomy.

Adult↗
PubMed2004

Hyperbaric oxygenation combined with streptokinase for treatment of arterial thromboembolism of the lower leg.

Thromboembolic occlusion of peripheral arteries is a common problem in patients referred to vascular surgery departments. Standard treatments include catheter aspiration techniques, use of fibrinolytic agents and surgical thrombendarterectomy. Recent reports have described the use of hyperbaric oxygen therapy in patients with limb ischemia, yet their main focus has been on patients with chronic disorders. We present the case of a 74-year-old woman with atrial fibrillation and acute thromboembolic occlusion of the posterior tibial artery. The patient presented with severe pain in the right calf, unresponsive to non-opioid parenteral analgesia and accompanied by coldness, numbness and partial motor palsy of the right foot. After 60 minutes of oxygenation in a hyperbaric chamber with a pressure of 2.2 bar, the pain receded, although without signs of restored blood flow in the occluded artery. After fibrinolytic therapy with streptokinase, patency of the posterior tibial artery was verified by return of palpable pulsations and color Doppler ultrasonography. By combining hyperbaric oxygenation and streptokinase in the treatment of lower-leg arterial thromboembolism we achieved regression of ischemic pain, prolongation of the survival time of tissues compromised by ischemia and resolved the cause of the ischemia. We believe the use of this therapeutic strategy in selected cases of peripheral arterial thromboembolism is justified.

Aged↗
PubMed2002

Treatment of venous thromboembolism.

The combination of unfractionated heparin or low molecular weight heparin and oral anticoagulants is currently the treatment of choice for most patients with venous thromboembolism. Oral anticoagulants are started at the same time and heparin is discontinued after at least 5 days when the levels of the International Normalized Ratio reach the therapeutic range between 2.0 and 3.0. Low molecular weight heparin has potential advantages over heparin and is administered in subcutaneous weight-adjusted fixed doses without need for monitoring. This has made the home treatment of a large proportion of patients possible. Randomized clinical trials and several subsequent reports from clinical practice have demonstrated the efficacy and safety of this approach. The results of currently ongoing trials aimed to assess the efficacy and safety of newer compounds for the initial treatment of venous thromboembolism are expected. Oral direct thrombin inhibitors or selective factor-Xa inhibitors have the potential to become the treatment of choice in the next decade. The optimal duration of the secondary prophylaxis with oral anticoagulants is still a matter of debate. The rate of recurrence has been shown to be elevated, particularly in patients with idiopathic venous thromboembolism. A 3-month therapy is therefore currently recommended when a transient risk factor is identified, life-long treatment is recommended for patients with a second episode of venous thromboembolism. The presence of active cancer or a thrombophilic state may require long-term anticoagulation, although not all the congenital hypercoagulable states seem to carry the same level of risk. In all other cases, 6 months are recommended, but a long-term monitoring of the patients is advisable. The use of more aggressive strategies such as thrombolysis is limited to patients presenting with massive pulmonary embolism or signs of right ventricular dysfunction.

Anticoagulants↗
PubMed2000

Hemostatic problems and thromboembolic complications in nephrotic children.

A hypercoagulable state and the risk of thromboembolism in both arterial and venous circulation is a relatively frequent and serious feature of nephrotic syndrome (NS) in children and adults. The aim of this study was to evaluate the coagulation states of children with NS before and after corticosteroid (CS) therapy and to compare the results with a healthy control group. The first group consisted of 49 nephrotic children (30 boys and 19 girls) with a mean age of 6. 5+/-4.9 years (range 1-16 years). The control group included 17 healthy children (9 boys and 8 girls). At the time of admission, all patients were evaluated for the presence of clinical thromboembolism, hematological and biochemical indicators of a hypercoagulative state, and renal disease. This was repeated after CS treatment. Deep vein thrombosis was observed in 2 nephrotic patients who had very low plasma antithrombin III (AT III) levels and fibrinogen levels above 750 mg/dl. Thus, the prevalence of thromboembolism was 4% in our pediatric nephrotic population. The mean AT III level of the study group was 68.2+/-23.4% at the onset of the disease, which was significantly lower than the level of the control group (84.0+/-7. 6%). Plasma AT III levels increased to 74.4+/-15.3% after CS treatment, which correlated with the serum albumin levels. However, there was no correlation with urinary protein excretion. Protein C levels were higher than controls during all stages of the disease in both steroid-responsive and -unresponsive patients. The mean protein S level was similar in both groups. Plasma fibrinogen and cholesterol levels were significantly higher in the study group but decreased to within normal limits with remission. Our study suggests that thromboembolic complications are not infrequent in children with NS, and may be related to low plasma AT III and albumin and high fibrinogen and cholesterol levels.

Adolescent↗
PubMed2001

Variation of plasma D-dimer following surgery: implications for prediction of postoperative venous thromboembolism.

The prognosis of venous thromboembolism is considerably influenced by an accurate and fast diagnosis. Although the role of D-dimer testing in the diagnosis of suspected venous thromboembolism is well established for outpatients, there is controversial evidence on the clinical usefulness of its measurement in surgical patients. In order to recognize patterns of variation of D-dimer following surgery and identify potential pitfalls in prediction of venous thromboembolic complications, plasma D-dimer was assayed in 30 patients undergoing major elective hip surgery and 20 patients undergoing laparoscopic cholecystectomy for acute cholecystitis. The postoperative variation of plasma D-dimer differed widely between the two subgroups. Patients undergoing laparoscopic cholecystectomy showed D-dimer concentrations persistently increased from the baseline to the 15th postoperative day, whereas patients undergoing hip surgery were characterized by a double peak, on the 1st and 7th postoperative days. Mean inter-individual daily coefficient of variations of plasma D-dimer throughout the postoperative period were 49% (range 39%-61%) for laparoscopic cholecystectomy and 101% (range 72%-156%) for orthopedic surgery. The markedly heterogeneous fluctuation of plasma D-dimer suggests that the postoperative activation of the hemostatic system depends on the type and time since surgery, thus limiting the clinical usefulness of D-dimer testing in the diagnostic approach to postoperative venous thromboembolism.

Arthroplasty, Replacement, Hip↗
PubMed2005

Venous thromboembolism in cancer patients referred to the American University of Beirut-Medical Center secondary to deep vein thrombosis; occurrence and risk factors.

BACKGROUND/OBJECTIVES: Cancer is a very important risk factor for the development of thromboembolic disorders. We conducted a retrospective study, in order to examine the rate of Deep vein thrombosis occurrence in cancer patients, as well as the effects of risk factors for DVT in cancer patients affected with DVT. METHODS: 148 patients were enrolled in this study. Several risk factors for DVT were retrospectively examined with the main emphasis being age, gender, obesity, previous history of past thromboembolic phenomena and metastatic disease. RESULTS: 55.5% of the study group was older than 60 years of age. Gender did not appear to be a significant risk factor. As for obesity, only 23% of our patients were defined as obese. An examination of previous history of thromboembolic conditions revealed that 16.8% had previous history of DVT, 1.3% developed a PE prior to presentation and 3.4% were positive for both DVT and PE. As for metastasis, 33.7% of our study population exhibited metastatic cancer upon their presentation. One interesting finding was that only 13 patients out of the 148 had been on DVT-prophylaxis prior to their admission. CONCLUSION: Cancer is an important risk factor for the development of thromboembolic phenomena, yet in most parts of the world, prophylaxis is discerned mostly through clinical judgement or local guidelines. With this in mind, and the additive effects of other risk factors, stricter medical practices and well-defined regimens should be set forth to protect cancer patients from these conditions.

Adult↗
PubMed1978

Thromboembolism in mitral porcine valve recipients.

A low incidence rate of thromboembolism has been reported in mitral porcine valve recipients. In contrast, 5 of 22 single mitral porcine valve recipients (23 percent) followed up in our clinic for a mean of 16 months had thromboembolic events. All patients but one were receiving long-term anticoagulant therapy. One thromboembolic event resulted in death, three in permanent neurologic deficits and one in a peripheral arterial occlusion. All five patients with emboli had atrial fibrillation and left atrial enlargement. Three had thromboembolic events before porcine heart valve implantation. In addition, five mitral porcine valve recipients who were not receiving anticoagulant therapy were examined at autopsy. Thrombus was identified in the left atrium in three patients, at the tissue-valve interface (sewing ring) in two, on the porcine valve cusps in one and in the right atrium in one. Factors influencing thrombus formation such as left atrial enlargement, atrial fibrillation and a prosthetic device are present after mitral porcine valve implantation and are indications for long-term anticoagulation therapy.

Adult↗
PubMed1993

Mitral valve Carpentier-Edwards bioprosthetic replacement, thromboembolism, and anticoagulants.

Patients undergoing mitral valve replacement (MVR) using a bioprosthesis are frequently placed on long-term anticoagulant treatment, and thereby lose the main advantage conferred by the bioprosthesis. To assess predictive factors of the need for long-term anticoagulant treatment, 100 consecutive patients surviving bioprosthetic MVR between 1977 and 1987 were followed up. The estimated thromboembolism-free survival was 88.9% +/- 3.6% after 6 years of follow-up. Preoperative risk factors for thromboembolism were supraventricular arrhythmia (p = 0.013) and a history of thromboembolism (p = 0.039). Among the preoperative and postoperative factors, only postoperative rhythm significantly influenced (p = 0.007) the thromboembolism-free survival, as determined by Cox regression analysis. Permanent anticoagulant treatment was instituted in 39 patients. Preoperative and peroperative risk factors associated with the need for long-term anticoagulant treatment, as evidenced by Fisher linear discriminant analysis, were supraventricular arrhythmia (p < 0.001), septal myotomy (p = 0.013), and predominant mitral stenosis (p = 0.013). Thus, in those patients with predominant mitral stenosis and supraventricular arrhythmia preoperatively, the subsequent need for permanent postoperative anticoagulant treatment is high, and the implantation of a mechanical valve is therefore recommended, providing there are no strict contraindications to anticoagulant treatment.

Adolescent↗
PubMed1994

Thromboembolism after the Fontan procedure and its modifications.

The frequency of thromboembolism after the Fontan procedure has not been specifically addressed. Seventy patients underwent this operation between 1987 and 1992, and complete information was available on 64. Forty-five had a right atrium-pulmonary artery anastomosis, 17 had a total cavopulmonary connection, and 2 had a right atrium-right ventricle anastomosis. No patient received anticoagulants for more than 8 months postoperatively. Seven patients died in the early postoperative period (< 30 days). Ten cases of thromboembolism were identified in the follow-up, which ranged from 6 to 55 months (mean follow-up, 24.5 +/- 17 months). They occurred 7 days to 4.5 years after the Fontan repair. Seven thombi were on the systemic venous or pulmonary aspect of the circulation and three, on the systemic arterial aspect. Freedom from thromboembolism was 75% at 4 years. We conclude that thromboembolism is common after the Fontan procedure; it can occur several days to years postoperatively; it is an important cause of morbidity; and it may partly explain late death after the Fontan operation. Our data suggest that all patients undergoing this procedure require long-term anticoagulant therapy.

Anticoagulants↗
PubMed1981

Fibrinolytic response and oral contraceptive associated thromboembolism.

A case-control study of fibrinolytic activity was conducted comparing 12 women with a recent history of thromboembolism while taking oral contraceptives and 28 matched female controls without a history of thromboembolism. All subjects had stopped using oral contraceptives at least 12 months prior to study. A new assay, recently developed in this laboratory, was used to evaluate the mean fibrinolytic response to venous occlusion in both cases and controls. The fibrinolytic response of all subjects was stratified into quartiles as previously described. While the controls segregated as expected, all 12 cases occurred in subjects whose fibrinolytic response fell in the first two quartiles with 8 of the 12 subjects having first quartile responses. The mean fibrinolytic response for all controls was 12.3 units while cases showed a mean response of only 3.9 units. The above data supports and extends our recent suggestion that low fibrinolytic response may signal a natural predisposition to venous thromboembolism which could be triggered by use of synthetic estrogens. However, these data do not support the use of this assay as a screening test for oral contraceptive related risk to thromboembolism since at least 50% of the control population also segregate in the first two quarters.

Caseins↗
PubMed1996

The increased risk of venous thromboembolism and the use of third generation progestagens: role of bias in observational research. The Transnational Research Group on Oral Contraceptives and the Health of Young Women.

A matched case-control study was undertaken in 10 centers in Germany and the United Kingdom to explore the association of current use of major combination oral contraceptives with the occurrence of venous thromboembolism. The cases recruited were 505 women aged 16-44 years with venous thromboembolism, controls were 1877 women (at least 3 controls per case) matched for 5-year age group and region without VTE. The main outcome measures were odds ratios derived by comparing current use of a specific oral contraceptive or group of OC against current use of other groups or against no current use of OC. The odds ratios (95% confidence intervals) for venous thromboembolism were: for third generation products (low dose ethinyloestradiol, gestodene and desogestrel) versus second generation products (low dose ethinyloestradiol, no gestodene and desogestrel, 1.5 (1.1 to 2.0), for third versus second generation products with norgestimate included in third generation, 1.6 (1.2 to 2.2). The odds ratios for current use for women aged 16-44 of specific progestagens versus levonorgestrel-containing compounds were 1.7 (1.1 to 2.6) for gestodene, 1.8 (1.2 to 2.6) for desogestrel, 1.9 (1.0 to 3.6) for norgestimate and 1.3 (0.7 to 2.5) for progestagen-only pills. For women aged 25 to 44 likely to be exposed to any of these progestagens, odds ratios for the comparison of progestagens versus levonorgestrel showed a successive increase by market introduction ranging from 1.5 (0.9 to 2.5) for desogestrel with 30 micrograms oestrogen content (introduced 1981) to 2.8 (1.3 to 6.5) for desogestrel with 20 micrograms oestrogen content (introduced 1992) significant in linear trend analysis (p = 0.00012). The influence of norgestimate classification as third or second generation product does not significantly alter the results regarding the association of third generation products and venous thromboembolism. A direct comparison of current use of norgestimate (which is primarily metabolized to levonorgestrel) versus levonorgestrel shows an increased odds ratio. The trend of increasing risk of progestagens by recency of market introduction when compared with levonorgestrel is strongly indicative of the existence of external bias due to attrition of susceptibles.

Adolescent↗
PubMed1994

The use of thromboembolic prophylaxis in oral and maxillofacial surgery.

OBJECTIVES: To investigate the use of thromboembolic prophylaxis in oral and maxillofacial surgery. DESIGN: Postal questionnaire. SETTING: Oral and maxillofacial surgery departments in the UK. SUBJECTS: Consultant Oral and Maxillofacial surgeons as listed in the BAOMS Handbook of Hospitals, Oral and Maxillofacial Surgery. MAIN OUTCOME MEASURES: Factors used in the decision to use thromboembolic prophylaxis and the methods of prophylaxis used. RESULTS: The response rate was 73%. Previous thromboembolism (85% of respondents), prolonged immobilisation (79%) and length or magnitude of operation (78% and 74%) were the most commonly used risk factors, in the decision to use prophylaxis against DVT. Pre-operative trauma, cardiovascular disease and varicose veins were the risk factors most infrequently used. No forms of prophylaxis were used by 18% of respondents, with the remaining respondents using a variety of methods. The most widely used methods were graduated elastic compression stockings (74%) and low dose subcutaneous heparin (73%). CONCLUSION: The majority of known risk factors were taken into account when considering the use of prophylaxis against DVT. The methods of thromboembolic prophylaxis used in oral and maxillofacial surgery are considered to provide a satisfactory degree of protection, in moderate and low risk patient groups.

Bandages↗