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PubMed2000

Another method to prevent venous thrombosis in microsurgery: an in situ venous catheter.

Free-flap failure is in the order of 4 to 10 percent. Heparin is more effective at preventing venous thrombosis than arterial thrombosis. This study was undertaken to investigate the efficacy of delivering heparin at a high dose locally but low dose systemically (heparin infusion via a catheter placed proximal to the venous anastomosis) to prevent venous thrombosis in microsurgery. A model of venous thrombosis was first established by a venous inversion graft in the rat femoral vein (this was performed in seven animals and resulted in 100 percent thrombosis). Saline and heparin were delivered proximal to the inverted vein graft to assess the effect of each in preventing venous thrombosis. Flow/patency distal to the inverted vein graft was assessed by observation under the microscope, the milk test, and rate of flow (flowmeter). Saline infused via a catheter proximal to the venous inversion graft resulted in 100 percent thrombosis in 10 animals. Heparin (100 U/ml at 2 to 3 ml/hour) infused through a catheter for 2 hours proximal to the anastomosis resulted in flow in all 10 animals during the infusion. Blood was also taken before beginning the procedure (control) and after the heparin infusion distal to the anastomosis (local partial thromboplastin time) as well as in the contralateral femoral vein (systemic). The control for all animals that received heparin was <3 minutes. The systemic partial thromboplastin time after heparin infusion was <3 minutes in seven animals, 3.3 minutes in two animals, and >7 minutes in one animal. The local partial thromboplastin time distal to the inverted vein graft was >10 minutes in nine animals and 3.7 minutes in one animal. The study also had a clinical component, in which a catheter was placed in a vein of the free flap, and heparin was infused over 5 days. This technique has been used in 83 consecutive free flaps. In three recent free flaps performed on the limbs, the local partial thromboplastin time (close to the anastomosis) was raised but the systemic time was normal. This technique offers a method in preventing venous thrombosis in microsurgery. It is simple to implement and is not associated with the systemic complications of heparin.

Adult↗
PubMed2000

Deep vein thrombosis after major spinal surgery: incidence in an East Asian population.

STUDY DESIGN: A prospective study of 313 patients who underwent major spinal surgery. OBJECTIVES: To determine the incidence of deep vein thrombosis after major spinal surgery in an east Asian population without antithrombotic prophylaxis. SUMMARY OF BACKGROUND DATA: Spinal surgery has been associated with few thrombotic complications (2-14%) compared with other reconstructive surgeries (20-70%). It has also been well documented that the incidence of deep vein thrombosis in east Asians (10%) is lower than in westerners (20-70%) in total joint replacements. There has been no previous report on the incidence of deep vein thrombosis after reconstructive spinal surgery in east Asians. METHODS: Three hundred thirteen patients who underwent major spinal surgery were evaluated prospectively. All patients were examined with duplex ultrasonography assessments of both lower extremities. No specific antithrombotic prophylaxis were used in any patients before or after surgery. RESULTS: There were four patients with positive findings of deep vein thrombosis on duplex ultrasonography, and there was only one with clinically symptomatic deep vein thrombosis. The overall incidence of thrombotic complications was 1.3%, and the incidence of symptomatic deep vein thrombosis was 0.3%. CONCLUSION: Considering the low rate of deep vein thrombosis, routine screening and prophylaxis for deep vein thrombosis appears unwarranted in east Asians before or after major spinal surgery.

Adolescent↗
PubMed2005

Transhepatic catheter-directed thrombectomy and thrombolysis of acute superior mesenteric venous thrombosis.

PURPOSE: To evaluate clinical outcomes after percutaneous treatment of superior mesenteric vein (SMV) thrombosis. MATERIALS AND METHODS: A retrospective chart review was conducted of all patients with SMV thrombosis treated with percutaneous catheter-directed thrombectomy/thrombolysis. The demographics of the study population, potential causative factors contributing to SMV thrombosis, and morbidity and mortality associated with therapy were assessed. RESULTS: Eleven patients (mean age, 44.3 years +/- 12.8) with SMV thrombosis were treated with percutaneous transhepatic catheter-directed thrombectomy/thrombolysis. Potential causative factors included recent major abdominal surgery, thrombophilic conditions, pancreatitis, and repetitive abdominal trauma. The mean duration between the onset of symptoms and percutaneous treatment was 8.6 days +/- 6.5. Computed tomography confirmed the clinical diagnosis in nine patients (81.8%). One patient (9.1%) had a bleeding complication, which was treated by chest tube drainage without long-term sequelae. One patient (9.1%) with refractory SMV thrombosis died of sepsis and multiple organ failure. No recurrent episode of SMV thrombosis or mortality was documented during a mean follow-up of 42 months +/- 22.5. CONCLUSIONS: Percutaneous transhepatic catheter-directed thrombectomy/thrombolysis for SMV thrombosis is associated with a rapid improvement in symptoms and low incidences of long-term morbidity and mortality. Percutaneous thrombectomy and thrombolysis should be considered in all patients with acute SMV thrombosis without evidence of bowel necrosis.

Acute Disease↗
PubMed2006

Elective laparoscopic splenectomy and thrombosis of the spleno-portal axis: a prospective study with ecocolordoppler ultrasound.

Thrombosis of the portal system is a potentially life-threatening but otherwise underappreciated complication after splenectomy. Nonspecific and mild onset symptoms are the cause of delay in diagnosis, and the short hospital stay after laparoscopic approach could even contribute to the difficulty of early detection of this condition. The aim of this study was to verify if planned imaging controls are able to discover this complication leading to a prompt treatment. Thirty-eight patients (19 males and 19 females with a mean age of 24 years) who underwent laparoscopic splenectomy at our institution were studied to identify clinical signs of thrombosis of the portal venous system and eventually associated factors. All the patients were enrolled in a protocol of imaging surveillance using a doppler ultrasound method. Postoperative thrombosis of the spleno-portal axis occurred in 7 patients (18.9%) of the series. In 3 cases (8.1%) the thrombus extended from the splenic vein to occlude the portal axis. The complication was symptomatic in 4 cases (10.8%), whereas in 3 cases, the thrombosis was an ultrasonographic surprise in totally asymptomatic patients. Thrombosis occurred even as late as 2 months after splenectomy. Splenomegaly was the only significant factor predictive of thrombosis. Only those patients who had an early detection of portal or splenic vein thrombosis had a recanalization of the veins with anticoagulant therapy. Patients with splenomegaly who underwent laparoscopic splenectomy are at risk of thrombosis of the portal system and should undergo strict imaging surveillance and aggressive anticoagulation therapy.

Adolescent↗
PubMed2006

Drug-eluting stents and stent thrombosis: a cause for concern?

Drug-eluting stents, most commonly sirolimus-eluting stents and polymer-based paclitaxel-eluting stents, are now widely used during percutaneous coronary interventions, and have largely replaced bare-metal stents to treat a variety of native coronary artery and saphenous vein graft lesions. Stent thrombosis, a complication of both bare-metal and drug-eluting stents, is associated with significant morbidity and mortality including high rates of myocardial infarction and death. Recently, several studies in the literature have raised concern about increased rates of overall stent thrombosis and late stent thrombosis in drug-eluting stents in the so-called 'real world' where off-label uses of drug-eluting stents are common. Hypersensitivity reactions to the polymers used in drug-eluting stents, delayed endothelialization of the stents, and discontinuation of dual antiplatelet therapy have all been implicated in the pathophysiology of drug-eluting stents stent thrombosis. The incidence of total stent thrombosis as well as late stent thrombosis, however, does not seem to be significantly higher in drug-eluting stents than in bare-metal stents. An important risk factor for stent thrombosis in both types of stents appears to be the premature discontinuation of dual antiplatelet therapy, and physicians should educate their patients about the importance of adhering to dual antiplatelet therapy, given the dire clinical consequences of stent thrombosis.

Angioplasty, Balloon, Coronary↗
PubMed2005

Study of portal vein thrombosis in patients with idiopathic portal hypertension in Japan.

BACKGROUND/AIMS: The aim of this study was to elucidate the incidence and clinical manifestations of portal vein thrombosis (PVT) in patients with idiopathic portal hypertension (IPH) in Japan during long-term follow-up. PATIENTS AND METHODS: Twenty-two patients with IPH were examined for PVT by sonography during a follow-up of 12+/-6 years. Clinical manifestations and patient outcome related to PVT were studied. Seventy patients with liver cirrhosis were examined by sonography as an incidence control of thrombosis. RESULTS: Nine IPH patients had portal thrombosis (9/22, 41%), a higher incidence than in liver cirrhosis patients (7/70, 10%). Those with thrombosis showed ascites, marked hypersplenism, and low serum albumin. Four patients with thrombosis died. Patients without thrombosis showed less clinical problems after long-term follow-up. Plasma antithrombin III and protein C activity decreased in almost half of the patients. However, there were no differences in these parameters between patients with and without thrombosis. CONCLUSIONS: In Japan, IPH patients had a high incidence of portal thrombosis, a significant factor for poor prognosis. Whether the management of PVT contributes to an improvement of a clinical course of IPH or not should be clarified in further study.

Adult↗
PubMed2005

Homocysteine, MTHFR and risk of venous thrombosis: a meta-analysis of published epidemiological studies.

CONTEXT: It has been suggested that elevated total plasma homocysteine levels are associated with the risk of venous thrombosis. OBJECTIVE: To assess the relationship of homocysteine and the MTHFR 677TT genotype and the risk of venous thrombosis by conducting a meta-analysis of all relevant studies. DATA SOURCES AND SELECTION: Studies (case-control or nested case-control) were identified by searches of electronic literature for relevant reports published before July 2003 on homocysteine and the MTHFR 677TT genotype and venous thrombosis as an end-point, by hand-searching reference lists of original articles (including meta-analyses) on this topic and by contact with investigators in the field. DATA EXTRACTION: A meta-analysis of 24 retrospective (n = 3289 cases) and three prospective studies (n = 476 cases) was carried out to examine the association of homocysteine with venous thrombosis. A meta-analysis of 53 studies (n = 8364 cases) of the MTHFR 677TT genotype (that increases homocysteine) was carried out to assess if this association is causal. DATA SYNTHESIS: A 5 micromol L(-1) higher measured homocysteine level was associated with a 27% (95% CI: 1-59) higher risk of venous thrombosis in prospective studies and a 60% (95% CI: 10-134) higher risk in retrospective studies. The 677TT genotype was associated with a 20% (95% CI: 8-32) higher risk of venous thrombosis compared with the 677CC genotype. In contrast with non-American studies, the 677TT genotype had no effect on venous thrombosis in North America, due probably to the higher intake of folate and riboflavin in North America. CONCLUSION: This meta-analysis of prospective and retrospective studies demonstrates a modest association of homocysteine with venous thrombosis. The elevated risk associated with the MTHFR 677TT genotype provides some support for causality.

Case-Control Studies↗
PubMed2002

Validation of the Canadian clinical probability model for acute venous thrombosis.

OBJECTIVE: To validate the predictive value of the Canadian clinical probability model for acute venous thrombosis, which, to the best of the authors' knowledge, has not been done in emergency department (ED) settings outside of Canada. METHODS: Demographic and clinical information, rapid D-dimer testing, and venous ultrasound imaging were obtained among patients presenting with clinically suspected venous thrombosis at a university-affiliated ED. A diagnosis of deep venous thrombosis (DVT) was made based on venous ultrasound test results or objectively documented venous thromboembolism during a 12-week follow-up period. The probability of venous thrombosis was calculated using the Canadian clinical probability model. RESULTS: Among 102 patients, 17 (17%) were diagnosed as having venous thrombosis initially or during the three-month follow-up period. The frequency of venous thrombosis among patients categorized as having high probability was 10 of 17 [59%, 95% confidence interval (95% CI) = 35% to 82%], 6 of 44 (14%, 95% CI = 4% to 24%) with intermediate probability, and 1 of 41 (2%, 95% CI = 0.1% to 11%) with low probability. This compares with respective values of 49%, 14%, and 3%, reported by Canadian researchers in an ED study. Forty-one of 102 (40%) patients had an alternate diagnosis as likely or more likely than venous thrombosis, but only three (7%, 95% CI = 2% to 18%) of these had venous thrombosis. CONCLUSIONS: Use of the Canadian probability model for DVT in this ED resulted in effective risk stratification, comparable to previously published results.

Adult↗
PubMed2005

Thrombosis in inflammatory bowel diseases: role of inherited thrombophilia.

BACKGROUND: Inflammatory bowel diseases (IBD) are characterized by an increased risk for venous and arterial thrombosis. Although the pathogenetic mechanisms of this predisposition are unclear, a possible role of inherited risk factors for thrombosis in determining this predisposition has been suggested. AIM: To evaluate the role of factor V Leiden (G1691A) and G20210A prothrombin gene mutations in determining the occurrence of thrombosis in IBD patients. PATIENTS AND METHODS: Forty-seven IBD patients (30 ulcerative colitis and 17 Crohn's disease) with a positive history for thrombosis (9 at arterial sites and 38 at venous sites) were enrolled in the study. For each patient, two non-IBD subjects matched for sex and age, type, and site of thrombosis were used as controls. Peripheral blood DNA specimens were amplified by PCR using appropriate primers and analyzed by restriction analysis on agarose gel electrophoresis. Statistical analysis was performed by means of Fisher's exact test. RESULTS: The total number of subjects with one or both mutations was significantly lower in IBD patients with thrombosis than in control subjects (12.8%vs 29.8%, respectively; p= 0.035, OR = 0.34, 95% CI 0.13-0.90). The total frequency of the mutated alleles was also significantly lower in IBD than in controls (7.4%vs 16.5%, respectively; p= 0.041, OR = 0.40, 95% CI 0.17-0.96). Prothrombotic mutations were particularly unfrequent in IBD patients with active disease at the time of thrombosis compared with patients with quiescent disease (8.0%vs 36.4%, respectively; p= 0.057, OR = 0.15, 95% CI 0.02-1.01). CONCLUSIONS: The major inherited risk factors for thrombosis are significantly less frequent in thrombotic IBD patients than in thrombotic non-IBD subjects, suggesting that acquired risk factors play the most relevant role in determining thromboembolic events observed in IBD patients, particularly during active phases of the disease.

Adult↗
PubMed2004

Thrombophilic factors are not the leading cause of thrombosis in Behçet's disease.

BACKGROUND: Venous and arterial thromboses occur in patients with Behçet's disease and are associated with significant morbidity and mortality. Studies on a possible association between the occurrence of thrombosis and thrombophilia in patients with this disease have been controversial. OBJECTIVE: To determine the prevalence of the most common thrombophilias and dyslipidaemia in patients with Behçet's disease with and without thrombosis. METHODS: Blood samples from 107 patients with Behçet's disease who had or did not have thrombosis were analysed for factor V Leiden, prothrombin G20210A polymorphism, methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism, factor VIII level, homocysteine and C reactive protein concentrations, dyslipidaemia, and plasma glucosylceramide. RESULTS: There was no difference between patients with and without thrombosis in the prevalence of prothrombin G20210A polymorphism, factor V Leiden, homozygous MTHFR C677T, or plasma concentrations of homocysteine, C reactive protein, or glucosylceramide. In contrast, patients with thrombosis were found to have significantly higher mean levels of factor VIII, total cholesterol, triglycerides, VLDL cholesterol, and apolipoproteins B-100, C-II, and C-III than those without thrombosis. Multistepwise logistic regression analysis showed that triglyceride concentration was the best marker associated with thrombosis (p = 0.008), with an estimated odds ratio of 1.58 (95% confidence interval, 1.09 to 2.30) for a difference of 40 mg/dl. CONCLUSIONS: Thrombophilia does not seem to play a major role in the tendency to thrombosis in Behçet's disease. However, dyslipidaemia, predominantly hypertriglyceridaemia, might be a risk factor.

Adolescent↗
PubMed2004

Combined use of rapid D-dimer testing and estimation of clinical probability in the diagnosis of deep vein thrombosis: systematic review.

OBJECTIVE: To summarise the evidence supporting the use of rapid d-dimer testing combined with estimation of clinical probability to exclude the diagnosis of deep venous thrombosis among outpatients. DATA SOURCES: Medline (June 1993 to December 2003), the Database of Abstracts and Reviews (DARE), and reference lists of studies in English. SELECTION OF STUDIES: We selected 12 studies from among 84 reviewed. The selected studies included more than 5000 patients and used a rapid D-dimer assay and explicit criteria to classify cases as having low, intermediate, or high clinical probability of deep vein thrombosis of the lower extremity among consecutive outpatients. REVIEW METHODS: Diagnosis required objective confirmation, and untreated patients had to have at least three months of follow up. The outcome was objectively documented venous thromboembolism. Two authors independently abstracted data by using a data collection form. RESULTS: When the less sensitive SimpliRED D-dimer assay was used the three month incidence of venous thromboembolism was 0.5% (95% confidence interval 0.07% to 1.1%) among patients with a low clinical probability of deep vein thrombosis and normal D-dimer concentrations. When a highly sensitive D-dimer assay was used, the three month incidence of venous thromboembolism was 0.4% (0.04% to 1.1%) among outpatients with low or moderate clinical probability of deep vein thrombosis and a normal D-dimer concentration. CONCLUSIONS: The combination of low clinical probability for deep vein thrombosis and a normal result from the SimpliRED D-dimer test safely excludes a diagnosis of acute venous thrombosis A normal result from a highly sensitive D-dimer test effectively rules out deep vein thrombosis among patients classified as having either low or moderate clinical probability of deep vein thrombosis.

Biomarkers↗
PubMed2003

Internal jugular vein thrombosis associated with hemodialysis catheters.

PURPOSE: To determine the prevalence of internal jugular vein thrombosis among patients undergoing hemodialysis in whom tunneled dialysis catheters were placed by interventional radiologists and to evaluate potential risk factors for thrombosis, such as the number of catheters inserted per patient through the right internal jugular vein, catheter type and material, total catheter days, and catheter-associated infection. MATERIALS AND METHODS: Ultrasonographic (US) evaluation of the right internal jugular vein was performed by interventional radiologists in 143 patients with a history of dialysis catheter placement. The examination focused on the detection of right internal jugular vein thrombosis, with or without occlusion. Total catheter days, catheter type, and catheter-related complications, most notably infection, were evaluated with database analysis for possible association with subsequent development of thrombosis. Statistical analysis of potential risk factors was performed with logistic regression models and chi2 tests. RESULTS: Evidence of right internal jugular vein thrombosis was present in 25.9% of the patients enrolled in the study. Among the veins with thrombosis, 62% were occluded. Only the mean number of catheters placed in the right internal jugular vein per patient was significant below the level of P =.20; therefore, a multivariate logistic regression model was not used. CONCLUSION: Prevalence of internal jugular thrombosis, both complete and incomplete, was higher in the study population than previously reported. The risk factors that were analyzed demonstrated no statistically significant association with development of thrombosis.

Catheters, Indwelling↗
PubMed2006

Central venous line-related thrombosis in children.

Central venous lines are used in critically ill children and in children with chronic conditions for the administration of intravenous therapy, such as fluids, medications, total parenteral nutrition and blood products. Although the use of central venous lines has greatly improved the quality of care in these children, these catheters may cause serious mechanical, infectious and thrombotic complications. The reported frequency of catheter thrombosis in children is low as 5% in studies including only symptomatic cases and high as 50% in studies where patients are systematically screened for catheter-related thrombosis. The risk factors for catheter-related thrombosis in children are associated with the methods used for catheter insertion and with individual patient characteristics, underlying diagnosis and treatment. The management of catheter-related thrombosis is largely dependent on the requirement of the catheter. If no longer required or nonfunctioning the catheter should be removed. If access is still required and the catheter is functioning, treatment with anticoagulation is recommended in the absence of contraindications. The management of radiographically detected asymptomatic thrombosis in children is less clear. Clinical studies of prophylaxis for catheter-related thrombosis are inconclusive and no definitive recommendations for prophylaxis in adults or in children with central venous thrombosis can be made. Properly designed studies are needed to assess the role of prophylactic anticoagulation for preventing catheter-related thrombosis.

Adolescent↗
PubMed2005

Clinical features of heparin-induced thrombocytopenia including risk factors for thrombosis. A retrospective analysis of 408 patients.

Immune mediated heparin induced thrombocytopenia (HIT) is a prothrombotic adverse effect of heparin. However, only a subgroup of patients with HIT develops thromboembolic complications. We aimed to identify risk factors for developing HITassociated thrombosis. We analyzed a registry of patients with clinical suspicion of HIT who tested positive using a sensitive functional assay. Patient information was obtained by a standardized questionnaire. By multivariate analysis the association of age, gender, type of patient population, and magnitude of the platelet count decline with the frequency, type (venous or arterial), and temporal pattern of thrombotic events was assessed. In 408 HIT patients we observed predominance of venous thrombosis (2.4:1), with 40% of patients developing a pulmonary embolism. However, in the subgroup of post-cardiovascular surgery patients there was predominance of arterial thrombosis (1:8.5). The type of arterial thrombosis (limb artery thrombosis > thrombotic stroke > myocardial infarction) was the converse of that observed with typical atherothrombotic clots in non-HIT populations. In 59.8% of patients HIT-related thrombosis manifested either on the same day a platelet count decrease >50% was documented (26.3%) or before the decrease in platelet counts (33.5%). The most important risk factors for thrombosis were orthopedic/trauma surgery and the magnitude of platelet count decrease. HIT-associated thrombosis occurs in a considerable proportion of patients before platelet counts decrease by more than 50%.

Adolescent↗
PubMed2003

Combination of a normal D-dimer concentration and a non-high pretest clinical probability score is a safe strategy to exclude deep venous thrombosis.

BACKGROUND: Serial ultrasonography is reliable for the diagnosis of deep venous thrombosis in symptomatic patients, but the low prevalence of thrombosis in this group renders the approach costly and inconvenient to patients. We studied the clinical validity of the combination of a pretest clinical probability score and a D-dimer test in the initial evaluation of patients suspected of deep venous thrombosis. METHODS AND RESULTS: Patients with a normal D-dimer concentration (<500 fibrin equivalent units [FEU] microg/L) and a non-high probability score (<3) had no further testing. Patients with a normal D-dimer concentration and a high probability score (> or =3) underwent one ultrasonogram. Serial ultrasonography was performed in patients with an abnormal D-dimer concentration. Patients were followed for 3 months. A total of 812 patients were evaluable for efficacy. Only 1 of 176 patients (0.6%; 95% CI, 0.02% to 3.1%) with a normal D-dimer concentration and a non-high probability score developed thrombosis during follow-up. A normal D-dimer concentration and a high probability score were found in 39 patients; 3 of them (7.7%; 95% CI, 1.6% to 20.9%) had thrombosis at presentation, and one (2.8%; 95% CI, 0.07% to 14. 5%) developed pulmonary embolism during follow-up. In 306 of 597 patients (51.3%) with an abnormal D-dimer concentration, thrombosis was detected by serial ultrasonography. Six patients (2.1%; 95% CI, 0.8% to 4. 4%) developed thrombosis during follow-up. No deaths due to thromboembolism occurred during follow-up. The total need for ultrasonography was reduced by 29%. CONCLUSION: The combination of a non-high pretest clinical probability score and a normal D-dimer concentration is a safe strategy to rule out deep venous thrombosis and to withhold anticoagulation.

Cohort Studies↗
PubMed2001

Stent thrombosis in the modern era: a pooled analysis of multicenter coronary stent clinical trials.

BACKGROUND: There are limited studies of stent thrombosis in the modern era of second-generation stents, high-pressure deployment, and current antithrombotic regimens. METHODS AND RESULTS: Six recently completed coronary stent trials and associated nonrandomized registries that enrolled 6186 patients (6219 treated vessels) treated with >/=1 coronary stent followed by antiplatelet therapy with aspirin and ticlopidine were pooled for this analysis. Within 30 days, clinical stent thrombosis developed in 53 patients (0.9%). The variables most significantly associated with the probability of stent thrombosis were persistent dissection NHLBI grade B or higher after stenting (OR, 3.7; 95% CI, 1.9 to 7.7), total stent length (OR, 1.3; 95% CI, 1.2 to 1.5 per 10 mm), and final minimal lumen diameter within the stent (OR, 0.4; 95% CI, 0.2 to 0.7 per 1 mm). Stent thrombosis was documented by angiography in 45 patients (0.7%). Clinical consequences of angiographic stent thrombosis included 64.4% incidence of death or myocardial infarction at the time of stent thrombosis and 8.9% 6-month mortality. CONCLUSIONS: Stent thrombosis occurred in <1.0% of patients undergoing stenting of native coronary artery lesions and receiving routine antiplatelet therapy with aspirin plus ticlopidine. Procedure-related variables of persistent dissection, total stent length, and final lumen diameter were significantly associated with the probability of stent thrombosis. Continued efforts to eliminate this complication are warranted given the serious clinical consequences.

Aspirin↗
PubMed1997

Effects of GP IIb/IIIa receptor monoclonal antibody (7E3), heparin, and aspirin in an ex vivo canine arteriovenous shunt model of stent thrombosis.

BACKGROUND: Thrombosis is an important limitation of metallic coronary stents, especially in smaller vessels in which shear rates are high. Monoclonal antibody to platelet glycoprotein IIb/IIIa receptor (7E3) has been shown to inhibit shear-induced platelet aggregation. In this study, we compared the effects of 7E3, heparin, and aspirin on stent thrombosis in an ex vivo arteriovenous shunt model of high-shear blood flow. METHODS AND RESULTS: An ex vivo arteriovenous shunt was created in 10 anesthetized dogs. Control rough-surface slotted-tube nitinol stents (n = 72) expanded to 2 mm in diameter in a tubular perfusion chamber were interposed in the shunt and exposed to flowing arterial blood at a shear rate of 2100s-1 for 20 minutes. The animals were treated with intravenous murine 7E3 (Fab')2 (0.2, 0.4, and 0.8 mg/kg), heparin (100 U/kg), or aspirin (10 mg/kg). Effects of the test agents on thrombus weight, platelet aggregation, platelet P-selectin expression, bleeding time, and activated clotting time (ACT) were quantified. 7E3 reduced stent thrombosis by 95% (20 +/- 1 to 1 +/- 1 mg, P < .001) and platelet aggregation by 94% (14 +/- 2 to 1 +/- 1 omega, P < .001) at the highest dose (0.8 mg/kg). 7E3 significantly prolonged bleeding time but had no effect on ACT and platelet P-selectin expression. Heparin prolonged ACT but had no significant effect on stent thrombosis or platelet aggregation. Aspirin, although it inhibited platelet aggregation by 65%, had no effect on stent thrombosis (19 +/- 2 versus 20 +/- 1 mg in controls). CONCLUSIONS: 7E3 produced a dose-dependent inhibition of acute stent thrombosis under high-shear flow conditions. Stent thrombosis was resistant to heparin and aspirin. Thus, 7E3 may be an effective agent for preventing stent thrombosis.

Abciximab↗
PubMed1993

Cerebral venous thrombosis associated with pregnancy and puerperium. Review of 67 cases.

BACKGROUND AND PURPOSE: Cerebral venous thrombosis is characterized by its clinical pleomorphism and pathogenetic variability. We studied 67 patients with cerebral venous thrombosis associated with pregnancy and puerperium and compared them with 46 other cases unrelated to obstetric causes to disclose differences in their clinical presentation, neuroradiological findings, clinical course, and prognosis. METHODS: In this retrospective study, we analyzed the clinical, laboratory, and neuroimaging findings of 113 patients collected consecutively at our institute. The diagnosis of cerebral venous thrombosis was confirmed by angiography, magnetic resonance imaging, or neuropathological study. RESULTS: Patients with cerebral venous thrombosis associated with pregnancy and puerperium were younger (average age, 26 versus 36 years), and in most, the onset of symptoms was acute (82% versus 54%; P = .003). The evolution of symptoms reached a plateau within 10 days in 70% of patients with thrombosis from obstetric causes, compared with only 45% in those from other causes (P = .01). Anemia was more frequent in the obstetric group (64% versus 26%; P = .00001). There were no differences regarding neurological and neuroradiological findings. Although the initial severity of illness was similar in both groups, the final outcome was considered good in 80% of patients with obstetric causes, compared with 58% of patients with other causes (P = .01); mortality rates were 9% and 33%, respectively (P = .002). CONCLUSIONS: Cerebral venous thrombosis associated with pregnancy and puerperium has a more acute onset and a better prognosis than thrombosis due to other causes. These findings might be helpful in the diagnostic and therapeutic strategies for patients with cerebral venous thrombosis.

Adolescent↗