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PubMed1998

Thromboembolic prophylaxis in 3575 hospitalized patients with atrial fibrillation. The Clinical Quality Improvement Network (CQIN) Investigators.

OBJECTIVE: To define contemporary utilization patterns of anticoagulant and antiplatelet therapy for thromboembolic prophylaxis in atrial fibrillation (AF). DESIGN: Retrospective medical records audit of patients admitted in 1993 and 1994. SETTING: Twelve Canadian hospitals. PATIENTS: Three thousand, three hundred and seventy-five consecutive patients with AF; 1570 females and 2005 males. The mean age was 72 years; 1353 patients were younger than 70 years and 2222 were aged 70 years and older. MEASUREMENTS AND RESULTS: Overall, 1188 (33%) of the 3575 patients received no prophylaxis, 852 (24%) were treated with warfarin alone, 1247 (35%) received acetylsalicylic acid (ASA) alone and 288 (8%) received both drugs. The pattern of medication use did not change appreciably when possible contraindications to warfarin or ASA therapy were considered. Among the 331 AF patients with valvular heart disease and no contraindications to thromboembolic prophylaxis, 65 (20%) received neither treatment, 181 (55%) received warfarin therapy alone, 46 (14%) received ASA alone and 39 (12%) received both. Among the 2199 AF patients with nonvalvular heart disease and no contraindications, 823 (37%) did not receive either therapy, 677 (31%) received ASA alone, 504 (23%) received warfarin alone and 195 (9%) received both. Elderly and female patients were less likely to receive thromboembolic prophylaxis. CONCLUSIONS: Anticoagulation and antiplatelet prophylaxis in AF appears to be less than optimal. Although concerns about bleeding may be one reason thromboembolic prophylaxis is so unevenly and incompletely applied, it will be important to determine the reasons for this practice and to develop effective strategies in order to enhance the process of care and patient outcomes.

Adult↗
PubMed1976

A clinical evaluation of aspirin prophylaxis of thromboembolic disease after total hip arthroplasty.

Prophylaxis of thromboembolic disease using aspirin was studied prospectively in 340 patients undergoing total hip replacement, excluding those with prior thromboembolic disease. Clinical criteria were used to diagnose thrombophlebitis, while clinical criteria, roentgenography, blood-gas determinations, electrocardiography, and pulmonary vascular scanning were used to diagnose pulmonary emboli. Five patients had signs of symptoms of pulmonary emboli, all confirmed by pulmonary vascular scan. No fatal pulmonary emboli occurred. Twenty-six patients had thrombophlebitis. Without simultaneous control group, a reduction in postoperative thromboembolic disease in these patients receiving aspirin was not proved. However, the observed low incidence of clinically evident thromboembolic manifestations suggests that aspirin may be a simple and useful prophylactic agent in these patients.

Adolescent↗
PubMed1998

[Venous thromboembolism--incidence and risk factors in Oslo].

Over a period of three years, 378 patients with objectively verified venous thromboembolism were treated at Aker University Hospital. Below the age of 60, men and women had about the same incidence of venous thromboembolism, but that age the incidence was significantly higher among men than among women. Incidence increased exponentially with age, from about 1:10,000 at age 20 to about 1:1,000 at age 50. The incidence found here is lower than in earlier Nordic studies. The great majority of the patients (93%) had deep venous thrombosis in the lower extremities, 11% had symptomatic and verified pulmonary embolism, and 1% had their thrombus in an inner organ vein. 23% of patients were previously treated for venous thromboembolism, and 22% had cancer. Seven women were on oral contraception, and 22 used postmenopausal hormone substitution. An obvious temporary precipitating factor was present in 42% of the patients, while 36% had a spontaneous venous thromboembolism. Hereditary thrombophilic disorder was found in 32% of patients below the age of 60.

Adolescent↗
PubMed2001

Comparison of the oral direct thrombin inhibitor ximelagatran with enoxaparin as prophylaxis against venous thromboembolism after total knee replacement: a phase 2 dose-finding study.

BACKGROUND: Up to one third of patients who undergo total knee replacement develop deep vein thrombosis after surgery despite receiving low-molecular-weight heparin prophylaxis. Ximelagatran is a novel direct inhibitor of free and clot-bound thrombin. METHODS: We performed a randomized, parallel, dose-finding study of 600 adults undergoing elective total knee replacement at 68 North American hospitals to determine the optimum dose of ximelagatran to use as prophylaxis against venous thromboembolism after total knee replacement. Patients received either ximelagatran twice daily by mouth in blinded fixed doses of 8, 12, 18, or 24 mg or open-label enoxaparin sodium, 30 mg, subcutaneously twice daily, starting 12 to 24 hours after surgery and continuing for 6 to 12 days. We measured the 6- to 12-day cumulative incidence of symptomatic or venographic deep vein thrombosis, symptomatic pulmonary embolism, and bleeding. RESULTS: A total of 594 patients received at least 1 dose of the study drug; 443 patients were evaluable for efficacy. Rates of overall venous thromboembolism (and proximal deep vein thrombosis or pulmonary embolism) for the 8-, 12-, 18-, and 24-mg doses of ximelagatran were 27% (6.6%), 19.8% (2.0%), 28.7% (5.8%), and 15.8% (3.2%), respectively. Rates of overall venous thromboembolism (22.7%) and proximal deep vein thrombosis or pulmonary embolism (3.1%) for enoxaparin did not differ significantly compared with 24-mg ximelagatran (overall difference, -6.9%; 95% confidence interval, -18.0% to 4.2%; P=.3). There was no major bleeding with administration of 24 mg of ximelagatran twice daily. CONCLUSION: Fixed-dose, unmonitored ximelagatran, 24 mg twice daily, given after surgery appears to be safe and effective oral prophylaxis against venous thromboembolism after total knee replacement.

Administration, Oral↗
PubMed2003

The incidence of recurrent venous thromboembolism after treatment with vitamin K antagonists in relation to time since first event: a meta-analysis.

BACKGROUND: After a first episode of venous thromboembolism, patients are treated with vitamin K (phytonadione) antagonists. There are indications that the risk of recurrence after treatment with vitamin K antagonists decreases relative to the time since the first event. The aim of the present meta-analysis is to describe the risk of recurrent venous thromboembolism after treatment with vitamin K antagonist in relation to the time since the index event. METHODS: Computerized searches in MEDLINE and EMBASE databases; reference checks of pertinent articles; personal communication with colleagues to find randomized clinical trials and cohort studies in which patients with venous thromboembolism were treated with vitamin K antagonists. Per treatment arm, 2 reviewers independently extracted data on the number of recurrent events and the duration of follow-up per time period of 3 months. RESULTS: A total of 135 potentially eligible studies were identified. Of these, 18 studies could be included, comprising 25 treatment arms that could be analyzed. Treatment arms were divided into 3 groups based on treatment duration (short, medium, and long). For all 3 groups, the monthly incidence immediately after discontinuation of treatment was high and declined rapidly thereafter. The monthly incidence after 9 months seemed independent of the treatment duration. CONCLUSIONS: There is a diminishing risk of recurrent venous thromboembolism over time and a stabilization after 9 months independent of the duration of the initial treatment with vitamin K antagonists. These findings have important implications for decision making about the optimal duration of treatment with vitamin K antagonists.

Anticoagulants↗
PubMedDate not supplied

Risk of venous thromboembolism after air travel: interaction with thrombophilia and oral contraceptives.

BACKGROUND: Conflicting data are available on air travel as a risk factor for venous thromboembolism. To our knowledge, there are no studies investigating whether individuals with thrombophilia and those taking oral contraceptives are more likely to develop venous thromboembolism during flights than those without these risk factors. PARTICIPANTS AND METHODS: The study sample consisted of 210 patients with venous thromboembolism and 210 healthy controls. DNA analysis for mutations in factor V and prothrombin genes and plasma measurements of antithrombin, protein C, protein S, total homocysteine levels, and antiphsopholipid antibodies were performed. RESULTS: In the month preceding thrombosis for patients, or the visit for controls, air travel was reported by 31 patients (15%) and 16 controls (8%), with an oddsratio of 2.1 (95% confidence interval, 1.1-4.0). Thrombophilia was present in 102 patients (49%) and 26 controls (12%), and oral contraceptives were used by 48 patients and 19 controls (61% and 27% of those of reproductive age, respectively). After stratification for the presence of air travel and thrombophilia, the odds ratio for thrombosis in individuals with both risk factors was 16.1 (95% confidence interval, 3.6-70.9). Stratification for the presence of air travel and oral contraceptive use gave an odds ratio of 13.9 (95% confidence interval, 1.7-117.5) in women with both risk factors. CONCLUSIONS: Air travel is a mild risk factor for venous thromboembolism, doubling the risk of the disease. When thrombophilia or oral contraceptive use is present, the risk increases to 16-fold and 14-fold, respectively, indicating a multiplicative interaction.

Adult↗
PubMed2002

Prophylaxis for venous thromboembolic disease in pregnancy and the early postnatal period.

BACKGROUND: Venous thromboembolic disease (TED), although very rare, is a major cause of maternal mortality and morbidity, hence methods of prophylaxis are often used for women at risk. This may include women delivered by caesarean section, those with a personal or family history of TED and women with inherited or acquired thrombophilias (conditions that predispose people to thrombosis). Many methods of prophylaxis carry a risk of side effects, and as the risk of thromboembolic disease is low, it is possible that the benefits of thromboprophylaxis may be outweighed by harm. Current guidelines for clinical practice are based on expert opinion only, rather than high quality evidence from randomised trials. OBJECTIVES: To determine the effects of thromboprophylaxis in association with pregnancy in women who are pregnant or have recently delivered on the incidence of venous thromboembolic disease and side effects. SEARCH STRATEGY: The register of trials maintained by the Cochrane Pregnancy and Childbirth Group, the Cochrane Controlled Trials Register, MEDLINE, EMBASE and bibliographies of reviews. Date of last search: January 2002. SELECTION CRITERIA: Randomised trials comparing one method of thromboprophylaxis with placebo or no treatment, and randomised trials comparing two (or more) methods of thromboprophylaxis. DATA COLLECTION AND ANALYSIS: Data were extracted independently by all reviewers. Discrepancies were resolved by discussion. MAIN RESULTS: Eight trials involving 649 women were included. Four of them compared methods of antenatal prophylaxis; low molecular weight versus unfractionated heparin (two studies), aspirin plus heparin versus aspirin alone (one study), and unfractionated heparin versus no treatment (one study). Four studies assessed postnatal prophylaxis after caesarean section; one compared hydroxyethyl starch with unfractionated heparin, two compared heparin with placebo (one low molecular weight heparin, one unfractionated heparin) and the other compared unfractionated heparin with low molecular weight heparin. It was not possible to assess the effects of any of these interventions on most outcomes, especially rare outcomes such as death, thromboembolic disease and osteoporosis, because of small sample sizes and the small number of trials making the same comparisons. REVIEWER'S CONCLUSIONS: There is insufficient evidence on which to base recommendations for thromboprophylaxis during pregnancy and the early postnatal period. Large scale randomised trials of currently-used interventions should be conducted.

Female↗
PubMed1995

Treatment of Venous Thromboembolism with Low-Molecular-Weight Heparin.

There is now ample evidence to indicate that certain low-molecular-weight heparins given subcutaneously can replace continuous intravenous unfractionated heparin for the initial treatment of venous thromboembolism. The low-molecular-weight heparins have a predictably high absorption rate when given subcutaneously and a prolonged duration of action, permitting them to be given by a once or twice daily injection for the prevention or treatment of venous thrombosis. Furthermore, treatment does not require laboratory monitoring, thus eliminating the need for continuous IV infusion and permitting the early discharge of patients with venous thromboembolism. This should eventually lead to the outpatient treatment of venous thromboembolism. Studies to date indicate that low-molecular-weight heparin is more cost-effective than unfractionated heparin in the treatment of venous thromboembolism and the cost effectiveness will be increased by out-of-hospital treatment. At the present time, the findings associated with any individual low-molecular-weight heparin preparation cannot be extrapolated to different low-molecular-weight heparins, and therefore each must be evaluated in separate clinical trials. The information to date is that low-molecular-weight heparin is safer and more effective than continuous intravenous unfractionated heparin in the treatment of proximal venous thrombosis. The decreased mortality rate seen in two clinical trials, particularly in patients with metastatic cancer, was quite unexpected. This requires further confirmation in larger prospective randomized trials.

Journal Article↗
PubMed2005

[Pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension].

Bilateral pulmonary thromboendarterectomy has been recognized as the first-choice therapeutic option for patients with chronic thromboembolic pulmonary hypertension. With careful patient selection, meticulous surgical technique and careful postoperative management the surgical procedure has proven potentially curative for these often severely incapacitated patients in whom prognosis is otherwise poor. By means of pulmonary angiography and multislice CT correct diagnosis is established and the crucial question of operability determined.In the presence of significant exertional dyspnea and/or elevation of pulmonary vascular resistance surgery is indicated when the thromboembolic obstructions are determined accessible to surgical removal. Suboptimal surgical results may be obtained in patients with solely peripheral location of lesions, i. e., beginning at the bronchopulmonary segmental arteries, and correct patient selection becomes crucial especially in advanced stages of disease of very high pulmonary vascular resistance and presence of right heart failure.The surgical techniques are standardized with use of median sternotomy with cardiopulmonary bypass, deep hypothermia and periods of circulatory arrest and consist of complete dissection of the intimal layer of the pulmonary branches containing the thromboembolic lesions as a true endarterectomy technique.The reported operative mortality for pulmonary thromboendarterectomy differs in the literature between 4.5% and 23.5% and probably reflects not only the various experiences with this patient group but most likely also the disparate policies in patient selection. The authors' experience comprises 250 surgically treated patients with an operative mortality of 14.4%. The immediate hemodynamic and functional improvement of patients following successful thromboendarterectomy is excellent with further improvement during the first year. Pulmonary hypertension recurs over time in a few patients because of embolism, thrombosis or progression of reactive vasculopathy. However, the functional improvement and decrease of right ventricular afterload are persistent in the vast majority.Given the poor results of lung transplantation, this is not an alternative, and patients with chronic thromboembolic pulmonary hypertension should undergo thromboendarterectomy, preferably in the most early stage of their disease.

Chronic Disease↗
PubMed2006

Calcified pulmonary thromboembolism in a child with sickle cell disease: value of multidetector CT in patients with acute chest syndrome.

The incidence of pulmonary embolism in children is not clearly known, but is believed to be low. Risk factors for pulmonary thromboembolism include central venous catheter, malignancy, surgery, infection, trauma, and congenital hypercoagulable disorders. Children with sickle cell disease are prothrombotic and are at an increased risk of thromboembolism. The incidence of this event is unknown because these children are often not thoroughly imaged. We report here a case of a calcified pulmonary thromboembolism in a child with sickle cell disease and emphasize the use of multidetector CT in detection of pulmonary thromboembolism in children with sickle cell disease.

Adolescent↗
PubMed2004

Thromboembolic prophylaxis as a risk factor for postoperative complications after breast cancer surgery.

Hematoma and bruising (sugillation) are frequent problems after operations for primary breast cancer. In the present study we evaluated the influence of various methods of perioperative thromboembolic prophylaxis on the postoperative incidence of hematoma and suggilation. From June 1994 through August 1996, a series of 425 patients consecutively operated on for primary breast cancer were included. Thromboembolic prophylaxis was low-molecular-weight heparin (LMWH) in 310 patients and thigh-long graded compression (TED) stockings in 102 patients. Postoperative complications including deep vein thrombosis, pulmonary embolism, wound hematoma, and sugillation were recorded, and 17 variables with a potential influence on complications were analyzed by logistic regression analysis. Heparin prophylaxis compared to prophylaxis with TED stockings was significantly and independently associated with postoperative hematoma [odds ratio (OR) 3, 13; 95% confidence interval (CI) 1.38-7.13] or sugillation (OR 3.34; 95% CI 1.93-5.78). No clinically overt thromboembolic complications were diagnosed. After operations for breast cancer we found that LMWH was significantly associated with postoperative hematoma and sugillation compared to TED stockings for perioperative thromboembolic prophylaxis.

Anticoagulants↗
PubMed2006

Influence of L-arginine on the expression of eNOS and COX2 in experimental pulmonary thromboembolism.

The influence of L-arginine on endothelial nitric oxide synthase (eNOS) and cyclooxygenase 2 (COX2) was observed in experimental pulmonary thromboembolism and the action mechanism on pulmonary thromboembolism was explored. Wistar rats were randomly divided into control group, model group and treatment group. Pulmonary thromboembolism models were established by auto-blood back transfusion, and L-Arg 100 mg/kg was intraperitoneally injected after successful model preparation. The animals were sacrificed at 3 h, 1 day, 3 days and 7 days after embolism. Plasma NO, TXB2 and 6-Keto-PGFla were detected. The expression of eNOS and COX2 protein and mRNA in pulmonary tissues was detected by immunohistochemistry and RT-PCR respectively. The results showed that pulmonary thrombosis could be seen post pulmonary embolism and inflammatory reaction was significant. Plasma NO was decreased (P<0.01), and the levels of TXB2, 6-Keto-PGF1alpha and T/P ratio were all elevated. The expression of eNOS protein and mRNA in the pulmonary tissue was down-regulated (P<0.05), while that of COX2 protein and mRNA was upregulated (P<0.01). In treatment group, the level of NO was increased, the levels of TXB2 and T/P ratio were decreased, but the level of 6-Keto-PGF1alpha was increased. The expression of eNOS protein and mRNA in pulmonary tissue was upregulated (P<0.05), while that of COX2 protein and mRNA was down-regulated (P<0.05). In conclusion, L-arginine can educe the role of pulmonary tissue protection through up-regulating the expression of intra-pulmonary NOS and down -regulating COX2 in pulmonary thromboembolism.

Animals↗
PubMed1986

Duration of warfarin anticoagulant therapy and the probabilities of recurrent thromboembolism and hemorrhage.

To determine the association of duration of warfarin anticoagulant therapy after hospitalization for venous thromboembolism with the probability of recurrent thromboembolism and with the risks of hemorrhage, medical records of 2,422 patients hospitalized in 1970 through 1980 with pulmonary embolism, thrombophlebitis, or both were reviewed. Multivariate life-table analyses were performed for 370 patients who had positive results of venography or pulmonary angiography, or who had lung scanning evidence of a "high probability" of pulmonary embolism and no history of the disease. For these patients, warfarin therapy for more than six weeks was not associated with a lower risk of recurrent thromboembolism when compared with warfarin therapy for one through six weeks (risk of recurrence for seven to 26 weeks of treatment 0.8; 95 percent confidence limits 0.3 and 2.5; risk of recurrence for more than 26 weeks of treatment 1.1; 95 percent confidence limits 0.4 and 3.1). The longer the warfarin therapy, the higher the risk of medically important complications from therapy. From one week through five years, the probability of major hemorrhage increased almost linearly: 10 percent for 12 weeks, 18 percent at one year, 26 percent at two years, and 41 percent at five years. This study suggests that intensive, long-term warfarin anticoagulation, in patients with a first episode of venous thromboembolism and no predisposing condition, is associated with more toxicity than efficacy and should be abandoned.

Actuarial Analysis↗
PubMed1994

Transesophageal echocardiography before and during direct current cardioversion of atrial fibrillation: evidence for "atrial stunning" as a mechanism of thromboembolic complications.

OBJECTIVES: The purpose of this study was to evaluate the usefulness of transesophageal echocardiography before electrical cardioversion in patients with atrial fibrillation and to determine the mechanism of thromboembolism after cardioversion. BACKGROUND: Thromboembolic complications after electrical cardioversion of atrial fibrillation have been attributed to the dislodgment of preexistent left atrial thrombus during the resumption of atrial contraction. Transesophageal echocardiography has been proposed as a method of screening patients for left atrial thrombus before cardioversion. METHODS: Seventy transesophageal echocardiographic studies were performed in 66 patients, predominantly with nonvalvular atrial fibrillation, before direct current cardioversion. In addition, transesophageal echocardiography was performed during the cardioversion procedure in 15 patients and immediately after in 1 patient. RESULTS: Left atrial thrombus was detected in one patient (1.4%), and cardioversion was cancelled. Thromboembolic complications occurred in 4 patients, none of whom had evidence of left atrial thrombus before cardioversion. Within 10 s of successful cardioversion, left atrial spontaneous echo contrast appeared in five patients, increased in one patient and was unchanged in nine patients. Patients with new or increased spontaneous echo contrast had more impaired atrial contraction and slower initial heart rates after cardioversion than those without. Left ventricular contraction was also impaired transiently by cardioversion. CONCLUSIONS: Transesophageal echocardiographic detection of left atrial thrombus before direct current cardioversion is important but infrequent in patients with predominantly nonvalvular atrial fibrillation. The occurrence of thromboembolic complications in the absence of demonstrable left atrial thrombus and the new development of spontaneous echo contrast in association with the transient atrial dysfunction ("stunning") caused by cardioversion suggest that cardioversion may promote new thrombus formation, in which case all patients should receive full anticoagulant therapy at the time of cardioversion.

Anticoagulants↗
PubMed2004

Pulmonary thromboembolism in Asians/Pacific Islanders in the United States: analysis of data from the National Hospital Discharge Survey and the United States Bureau of the Census.

PURPOSE: To assess the rate of diagnosis of deep venous thrombosis, pulmonary embolism, and venous thromboembolism; the incidence in hospitalized patients; and mortality from pulmonary embolism among Asians/Pacific Islanders in the United States. METHODS: The number of patients discharged from hospitals with a diagnostic code for pulmonary embolism or deep venous thrombosis from 1990 through 1999 was obtained from the National Hospital Discharge Survey. Population estimates and deaths from pulmonary embolism from 1990 through 1998 were obtained from the United States Bureau of the Census. RESULTS: Rate ratios of 10-year age-adjusted rates of diagnosis of deep venous thrombosis, pulmonary embolism, and venous thromboembolism comparing Asians/Pacific Islanders with whites and African Americans ranged from 0.16 to 0.21. Rate ratios comparing incidences in hospitalized patients ranged from 0.32 to 0.42. The age-adjusted rate ratio of mortality in "others" (which included Asians/Pacific Islanders) was 0.29 (95% confidence interval [CI]: 0.01 to 0.87) compared with whites and 0.14 (95% CI: 0.0 to 0.58) compared with African Americans. CONCLUSION: Rates of deep venous thrombosis, pulmonary embolism, and venous thromboembolism; incidences in hospitalized patients; and the mortality rate from pulmonary embolism were markedly lower in Asians/Pacific Islanders than in whites and African Americans. Clinical assessment of the prior probability of venous thromboembolic disease at the bedside should probably be adjusted based on these ethnic differences.

Adolescent↗
PubMed2005

Low-molecular-weight heparins for the treatment of acute coronary syndrome and venous thromboembolism in patients with chronic renal insufficiency.

The clinical management of patients with renal insufficiency who develop an acute coronary syndrome or venous thromboembolism is a common clinical scenario that is problematic because of the lack of well-designed randomized trials assessing management strategies in such patients. Impaired renal function is common in patients who develop thromboembolic disorders, particularly in elderly patients in whom renal insufficiency is under-recognized. Low-molecular-weight heparins (LMWHs), which are the most widely used anticoagulant for the treatment of patients with an acute coronary syndrome or venous thromboembolism, are eliminated primarily by the kidney and, therefore, pose treatment challenges in patients with impaired renal function. However, there is emerging evidence regarding the use of LMWHs in patients with impaired renal function suggesting that some preparations may be safe in such patients. The objective of this review is to discuss the clinical management of patients with renal insufficiency who develop an acute coronary syndrome or venous thromboembolism, and to explore similarities and differences of LMWHs when used in this clinical setting.

Acute Disease↗
PubMed1999

Pulmonary thromboendarterectomy for chronic thromboembolic obstruction of the pulmonary artery in piglets.

OBJECTIVE: The 2 main causes of death after thromboendarterectomy for chronic pulmonary thromboembolism are incomplete repermeabilization responsible for persistent pulmonary hypertension and acute high-permeability pulmonary edema. We wish to establish an experimental model of chronic pulmonary thromboembolism to replicate the conditions encountered during and after pulmonary thromboendarterectomy. METHODS: Multiple-curled coils and tissue adhesive were embolized in 6 piglets to induce complete obstruction of the left pulmonary artery, documented by angiography. After 5 weeks, the main pulmonary artery was repermeabilized by thromboendarterectomy during circulatory arrest. The left lung was reperfused ex vivo with autologous blood at constant flow, and patency of the pulmonary artery was evaluated on a barium angiogram. The endarterectomy-reperfusion procedure was also done in 6 nonembolized piglets that served as the controls. The severity of lung injury induced by 60 minutes of reperfusion was assessed on the basis of measurements of the lung filtration coefficient and of lung myeloperoxidase activity. RESULTS: Marked hypertrophy of the bronchial circulation was seen in the chronic pulmonary thromboembolism group. Thromboendarterectomy removed the organized obstructing thrombus that was incorporated into the arterial wall and restored patency of the pulmonary artery. Acute lung inflammation and high-permeability edema occurred after reperfusion, as indicated by a 1.5-fold increases in both lung filtration coefficient and lung myeloperoxidase values in the chronic pulmonary thromboembolism group; these 2 variables being correlated. CONCLUSIONS: Our model replicated the perioperative conditions of pulmonary thromboendarterectomy, suggesting that it may prove useful for improving the repermeabilization technique and for investigating the mechanisms and prevention of reperfusion injury.

Animals↗
PubMed2002

Enhanced platelet aggregation with TRAP-6 and collagen in platelet aggregometry in patients with venous thromboembolism.

The role of platelet hyperaggregability as a possible risk factor for venous thromboembolism is not well defined. Some authors described enhanced maximal platelet aggregation in platelet aggregometry as a contributing factor for arterial and venous thrombosis. This syndrome has been termed "sticky-platelet syndrome" (SPS). The diagnosis of SPS is based on the demonstration of platelet hyperaggregability in aggregometry after stimulation with epinephrine (EPI) and/or adenosine diphosphate (ADP). We investigated platelet hyperaggregability in platelet-rich plasma (PRP) of patients (n = 34) with unexplained venous thromboembolism in comparison to healthy individuals (n = 53). For analysis, platelet aggregometry was performed and the influence of epinephrine, adenosine diphosphate, collagen (Coll) and thrombin receptor-activated peptide (TRAP-6) as agonist were determined. Compared to the control group, patients with venous thromboembolism showed an enhanced maximal platelet aggregation with low concentrations of TRAP-6 (2 microM) and collagen (0.05 microM). In contrast, we could not detect an increased platelet aggregation with EPI or ADP. Our results indicate that platelet hyperaggregability may represent an independent risk factor in patients with otherwise unexplained venous thromboembolism. In our study, low concentrations of TRAP-6 and collagen are superior to EPI and ADP to define platelet hyperreactivity in platelet aggregometry.

Adult↗