Thrombotic Artery Occlusion Research Articles

Neointimal formation is reduced after arterial injury in human crp transgenic mice

Objectives/Methods Elevated CRP levels predict increased incidence of cardiovascular events and poor outcomes following interventions. There is the suggestion that CRP is also a mediator of vascular injury. Transgenic mice carrying the human CRP gene (CRPtg) are predisposed to arterial thrombosis post-injury. We examined whether CRP similarly modulates the proliferative and hyperplastic phases of vascular repair in CRPtg when thrombosis is controlled with daily aspirin and heparin at the time of trans-femoral arterial wire-injury. Results Complete thrombotic arterial occlusion at 28 days was comparable for wild-type and CRPtg mice (14 and 19%, respectively). Neointimal area at 28d was 2.5 fold lower in CRPtg (4190 ± 3134 μm 2, n = 12) compared to wild-types (10,157 ± 8890 μm 2, n = 11, p < 0.05). Likewise, neointimal/media area ratio was 1.10 ± 0.87 in wild-types and 0.45 ± 0.24 in CRPtg ( p < 0.05). Seven days post-injury, cellular proliferation and apoptotic cell number in the intima were both less pronounced in CRPtg than wild-type. No differences were seen in leukocyte infiltration or endothelial coverage. CRPtg mice had significantly reduced p38 MAPK signaling pathway activation following injury. Conclusions The pro-thrombotic phenotype of CRPtg mice was suppressed by aspirin/heparin, revealing CRP's influence on neointimal growth after trans-femoral arterial wire-injury. Signaling pathway activation, cellular proliferation, and neointimal formation were all reduced in CRPtg following vascular injury. Increasingly we are aware of CRP multipotent effects. Once considered only a risk factor, and recently a harmful agent, CRP is a far more complex regulator of vascular biology.

Rivaroxaban — An Oral, Direct Factor Xa Inhibitor — Prevents Arterial Thrombotic Occlusion in Electrolytically Injured Rat Carotid Arteries.

Introduction: Rivaroxaban is an oral, direct Factor Xa (FXa) inhibitor in advanced clinical development for the prevention and treatment of thromboembolic disorders, including arterial indications such as acute coronary syndromes (ACS). The aim of this study was to determine whether rivaroxaban can prevent arterial thrombotic occlusion in electrolytically injured rat carotid arteries. Methods: Anesthetized, male Sprague-Dawley rats were equipped with an intravenous (i.v.) catheter to administer drug or vehicle and an intra-arterial catheter for arterial pressure monitoring and blood sampling. The left carotid artery was exposed and a bipolar electrode placed proximally around it. A pulsed Doppler flow probe was then placed distally around the vessel. Blood was obtained before drug or vehicle administration to determine activated clotting time (ACT), prothrombin time (PT), Russell’s viper venom time (RVVT), activated partial thromboplastin time (aPTT) and thrombin-antithrombin (TAT) complex concentration; baseline carotid blood flow was recorded for 20 minutes. Vehicle (polyethylene glycol:ethanol:water or saline, 0.5 mL/kg/min), rivaroxaban (0.3, 1 and 3 mg/kg; dosing volume 0.5 mL/kg/min), or the low molecular weight heparin enoxaparin (10 mg/kg) were infused i.v. over 30 seconds. After infusion, direct current (3 mA) was applied to the left carotid artery for 5 minutes. Blood flow was monitored for 30 minutes after injury. Blood was sampled again 14.5 and 30 minutes after injury for ACT determination, and after 30 minutes for PT, RVVT, TAT and aPTT determination. Results: Rivaroxaban dose-dependently increased the median time to arterial thrombotic occlusion (TTO), and was significantly more effective than vehicle at doses of 1 and 3 mg/kg (vehicle, 13.2 minutes; rivaroxaban 1 and 3 mg/kg, &gt;30 minutes; P&lt;0.05 by Kaplan-Meier analysis). Compared with enoxaparin (10 mg/kg), rivaroxaban inhibited TTO at doses of 1 and 3 mg/kg more effectively. Rivaroxaban (0.3–3 mg/kg i.v.) dose-dependently prolonged ACT, PT and RVVT, and substantially decreased the formation of TAT complexes, but did not substantially affect aPTT. Enoxaparin prolonged ACT, aPTT and RVVT, and decreased TAT complex formation, but had no effect on PT. Conclusions: Rivaroxaban potently inhibited electrolytically induced arterial thrombotic occlusion in rat carotid arteries, resulting in substantial changes in coagulation parameters. The coagulation parameter changes were consistent with inhibition of FXa activity as indexed by the RVVT. These findings suggest that rivaroxaban may be an effective anticoagulant in arterial thrombotic disorders, such as ACS.

Rivaroxaban — An Oral, Direct Factor Xa Inhibitor — Prevents Arterial Thrombotic Occlusion in Electrolytically Injured Rat Carotid Arteries.

Introduction: Rivaroxaban is an oral, direct Factor Xa (FXa) inhibitor in advanced clinical development for the prevention and treatment of thromboembolic disorders, including arterial indications such as acute coronary syndromes (ACS). The aim of this study was to determine whether rivaroxaban can prevent arterial thrombotic occlusion in electrolytically injured rat carotid arteries.Methods: Anesthetized, male Sprague-Dawley rats were equipped with an intravenous (i.v.) catheter to administer drug or vehicle and an intra-arterial catheter for arterial pressure monitoring and blood sampling. The left carotid artery was exposed and a bipolar electrode placed proximally around it. A pulsed Doppler flow probe was then placed distally around the vessel. Blood was obtained before drug or vehicle administration to determine activated clotting time (ACT), prothrombin time (PT), Russell's viper venom time (RVVT), activated partial thromboplastin time (aPTT) and thrombin-antithrombin (TAT) complex concentration; baseline carotid blood flow was recorded for 20 minutes. Vehicle (polyethylene glycol:ethanol:water or saline, 0.5 mL/kg/min), rivaroxaban (0.3, 1 and 3 mg/kg; dosing volume 0.5 mL/kg/min), or the low molecular weight heparin enoxaparin (10 mg/kg) were infused i.v. over 30 seconds. After infusion, direct current (3 mA) was applied to the left carotid artery for 5 minutes. Blood flow was monitored for 30 minutes after injury. Blood was sampled again 14.5 and 30 minutes after injury for ACT determination, and after 30 minutes for PT, RVVT, TAT and aPTT determination.Results: Rivaroxaban dose-dependently increased the median time to arterial thrombotic occlusion (TTO), and was significantly more effective than vehicle at doses of 1 and 3 mg/kg (vehicle, 13.2 minutes; rivaroxaban 1 and 3 mg/kg, >30 minutes; P<0.05 by Kaplan-Meier analysis). Compared with enoxaparin (10 mg/kg), rivaroxaban inhibited TTO at doses of 1 and 3 mg/kg more effectively. Rivaroxaban (0.3–3 mg/kg i.v.) dose-dependently prolonged ACT, PT and RVVT, and substantially decreased the formation of TAT complexes, but did not substantially affect aPTT. Enoxaparin prolonged ACT, aPTT and RVVT, and decreased TAT complex formation, but had no effect on PT.Conclusions: Rivaroxaban potently inhibited electrolytically induced arterial thrombotic occlusion in rat carotid arteries, resulting in substantial changes in coagulation parameters. The coagulation parameter changes were consistent with inhibition of FXa activity as indexed by the RVVT. These findings suggest that rivaroxaban may be an effective anticoagulant in arterial thrombotic disorders, such as ACS.

Abstract 1029: Stromelysin-1 is Critical For Intracranial Bleeding After Tissue-type plasminogen activator Treatment Of Stroke In Mice

Background: Tissue-type plasminogen activator (t-PA) is approved for treatment of ischemic stroke patients, but it may increase the risk of intracranial bleeding (ICB). Matrix metalloproteinases (MMPs), which can be activated through the plasminogen/plasmin system, may contribute to ICB after ischemic stroke. Objectives: To explore the contribution of plasminogen, MMP-3 and MMP-9 to ICB associated with t-PA treatment after ischemic stroke. Methods: Using a thrombotic middle cerebral artery occlusion (MCA-O) model, ICB was studied in mice with genetic deficiencies of plasminogen (Plg −/ − ), stromelysin-1 (MMP-3 −/ − ) or gelatinase B (MMP-9 −/ − ) and their corresponding wild-type (WT) littermates. t-PA (10 mg/kg) or its equivalent volume of solvent was administered intravenously 4 hours after MCA-O. The induction of MMP-3 and MMP-9 was also studied in C57BL/6 WT mice. Results: In MMP-3 +/+ WT mice given solvent, ICB was 4.3 ± 2.9 mm 3 (mean ± SD), which was significantly increased with tPA treatment to 9.7 ± 4.7 mm 3 (P&lt;0.05), whereas ICB in MMP-3 −/ − mice was not altered by t-PA treatment (5.7 ± 2.7 mm 3 , as compared to 5.1 ± 1.8 mm 3 without tPA; n = 7–9 in each group). ICB induced by t-PA was significantly less in Plg −/ − (5.7 ± 3.9 mm 3 ) than in WT mice (8.8 ± 3.2 mm 3 , p&lt;0.05) but ICB by t-PA in MMP-9 −/ − (8.3 ± 2.3 mm 3 ) was comparable with that in WT (8.3 ± 3.1 mm 3 ; n=8 –12 in each group). Administration of the broad-spectrum MMP inhibitor GM6001 after t-PA treatment reduced ICB significantly in MMP-3 +/+ (from 6.4 ± 1.9 mm 3 to 4.1 ± 1.9 mm 3 , p&lt;0.05) but not in MMP-3 −/ − mice (2.2 ± 0.6 mm 3 without versus 2.9 ± 1.5 mm 3 with GM6001; n=6 – 8 in each group). MMP-3 expression was significantly enhanced at the ischemic hemisphere; with placebo treatment, it was expressed only in neurons, whereas it was upregulated in endothelial cells with t-PA treatment. Although MMP-9 expression was also significantly enhanced at the ischemic brain, the amount and the distribution were comparable in mice with and without t-PA treatment. Conclusions: Our data with gene deficient mice suggest that plasminogen and MMP-3 are relatively more important than MMP-9 for the increased ICB induced by t-PA treatment of ischemic stroke.

Cryofibrinogenaemia

A 41-year-old woman presented with a 5-year history of arthralgia, Raynaud phenomenon and recurrent acral ulcerations that were affecting her nose, ears, fingers and feet, especially after cold exposure. Physical examination showed an erythematous nose with early ulceration (top left) and an irregularly shaped white scar (arrow) and a small haemorrhagic crust (arrowhead) of the fifth finger on the left hand (right). Laboratory findings included a normal complete blood cell count, biochemical profile and thrombophilia study with negative tests for cryoglobulinaemia, syphilis, viral hepatitis and autoantibodies. A skin biopsy from the edge of the finger ulcer showed numerous fibrin thrombi in the small dermal vessels. The above findings led us to test for a cryofibrinogen, which was demonstrated by the detection of white precipitate when the citrated plasma was maintained at 4°C for 72 h (middle, bottom of tube). This dissolved completely upon warming and was not detected in serum. The cryoprecipitate was studied by two-dimensional electrophoresis, demonstrating the α, β and γ chains of fibrinogen (bottom left). A diagnosis of essential cryofibrinogenaemia was made and the patient was treated with stanozolol, an androgen with known fibrinolytic activity, resulting in the resolution of her lesions. Cryofibrinogenaemia is defined by the presence of a reversibly cryoprecipitable protein in plasma but not in serum, together with cutaneous manifestations as well as cold sensitivity, purpura, livedo reticularis, Raynaud phenomenon, and skin ulcers or necrosis. It may be essential or secondary to an underlying disorder, such as lymphoma, carcinoma and acute infections, autoimmune and thromboembolic diseases. Cryofibrinogen is composed of fibrinogen, fibrin and smaller amounts of other proteins, which may cause thrombotic occlusion of the small arteries. In patients with otherwise unexplained skin ulcers, determination of plasma cryofibrinogen should be considered.

Cardiac arrest in a patient with a mobile right atrial thrombus in transit and amyloidosis

Primary amyloidosis is a rare disorder in which insoluble fibers are deposited in tissue and organs, impairing their function. Cardiac involvement occurs in up to 50% of patients with primary amyloidosis. We describe a case of a 75-year-old admitted to our department after he had a sudden cardiac arrest due to massive bilateral thrombotic occlusion of the pulmonary arteries. The echocardiogram revealed many atrial thrombi swirling inside the right atrium and protruding into the tricuspid valve partly occluding it. Severe concentric hypertrophy of the left ventricle was also present with a preserved ejection fraction. The right ventricle was dilated, hypertrophic and ipokinetic with a severe tricuspidal insufficiency that permitted estimation of a severe pulmonary hypertension. All these characteristics were highly suggestive for an infiltrative form of hypertrophic cardiomyopathy. The final diagnosis was amyloidosis.

Antiphospholipid Syndrome and Cognition

In addition to the well-defined neurologic events due to arterial and venous thrombotic vascular occlusions of antiphospholipid syndrome (APS), a broad spectrum of neuropsychiatric has been related to antiphospholipid (aPL). Experimental evidence of a pathogenic role of aPL in mice with impaired neurological function disclosed inflammatory reaction as a hallmark. The process that leads to neurological dysfunction seems to be both structurally destructive and functionally impairing. The most modern resources of neuroimmaging also suggest that, in addition to the micro-infarcts that occur in strategic areas, other metabolic impairments are related to progressive dementia and aPL presence. Although there is a lot of confusion among APS and lupus' cognitive involvement, there is a body of experimental and clinical evidence that aPL causes this kind of damage.

Von Willebrand factor in CHD and stroke: Relationships and therapeutic implications

Atherosclerotic cardiovascular disease (CVD), which includes coronary heart disease (CHD) and stroke, is now the most common cause of death in the middle aged and elderly in all parts of the world except subSaharan Africa. The direct cause of death is frequently an acute thrombotic arterial occlusion. Because atherosclerosis is a diffuse disease, patients with CHD also have a high risk of ischemic stroke. The hemostatic process is a needed defense mechanism to control hemorrhage after injury but at same time, if overactive, may have the potential to precipitate diseases such as myocardial infarction or stroke in the setting of atherosclerosis. In approximately 1% of all patients with ischemic stroke, and in up to 4% of young adults with stroke, the major precipitant of brain ischemia is a hematologic disorder or coagulopathy that predisposes to thrombosis. von Willebrand factor (vWF) plays an important role in platelet adhesion to subendothelial structures and in the intrinsic pathway of coagulation. It is regarded as an indirect measure of endothelial dysfunction. Deficiency of vWF in von Willebrand's disease is well established. However, much less is known regarding the pathophysiologic implications of an elevated level of vWF, particularly in relation to CVD and cerebrovascular disease. The importance of vWF in the pathogenesis of this disease is poorly defined and information is limited and inconsistent. Elevated levels of vWF have been variably linked with risk of CHD; causal criteria are not fully met. Relationships with stroke risk are even less well established. Measurement of vWF adds little to risk prediction after considering the major risk factors--age, sex, smoking, raised blood cholesterol, and hypertension. vWF may have a greater role in predicting outcome in subjects with acute coronary syndromes (ACS), stroke, and perhaps atrial fibrillation. Investigation of the use of vWF level to guide treatment of ACS or stroke is ongoing; however, there is no compelling evidence to date.

Kawasaki disease: diagnosis, management and cardiac sequelae

Kawasaki disease (KD) is an acute self-limiting systemic vasculitis of unknown etiology and the most common cause of acquired coronary disease in children aged 6 months to 5 years. The inflammatory process results in coronary arteritis, aneurysmal lesions, arterial thrombotic occlusion or even sudden death. The diagnostic tests are unknown but treatment with immunoglobulin and aspirin is effective at reducing cardiac complications from 25 to 4.7% in the UK. Myocardial, endocardial or pericardial inflammation may occur acutely or many years later and abnormalities of myocardial blood flow may require ongoing medication, interventional catheterization or even cardiac surgery. There are several new drugs that may have important roles to play in managing KD in children and young adults.

Molecular Imaging of Human Thrombus With Novel Abciximab Immunobubbles and Ultrasound

Molecular imaging of therapeutic interventions with targeted agents that simultaneously carry drugs or genes for local delivery is appealing. We investigated the ability of a novel microbubble carrier (immunobubble) for abciximab, a glycoprotein IIb/IIIa receptor inhibitor, for ultrasonographic molecular imaging of human clots. Human thrombi were incubated with immunobubbles conjugated with abciximab. Control clots were incubated in either saline or with immunobubbles conjugated with nonspecific antibody. We evaluated immunobubble suspensions with variable concentrations of encapsulated gas and measured mean acoustic intensity of the incubated clots. In vivo molecular imaging of human thrombi with abciximab immunobubbles was evaluated in a rat model of carotid artery occlusion. Mean acoustic intensity was significantly higher for abciximab immunobubbles as compared with control immunobubbles under all conditions tested with maximum difference in intensity at a gas volume of 0.2 microL (P=0.0013 for mechanical index 0.05, P=0.0001 for mechanical index 0.7). Binding of abciximab immunobubbles to clots in vitro led to enhanced echogenicity dependent on bubble concentration. In vivo ultrasonic detectability of carotid thrombi was significantly higher for clots targeted with abciximab immunobubbles (P<0.05). Quantification of in vivo contrast enhancement displayed a highly significant increment for abciximab immunobubble-targeted clots compared with nonspecific immunobubble-targeted clots (P<0.0001) and to native clots (P<0.0001). This study demonstrates the feasibility of using a therapeutic agent for selective targeting in vascular imaging. Abciximab immunobubbles improve visualization of human clots both in vitro and in an in vivo model of acute arterial thrombotic occlusion.

Emergency Use of Stent and rtPA with Mechanical Cloth Defragmentation for a Thromboembolic Complication during GDC Coil Treatment of an Acutely Ruptured Basilar Tip Aneurysm

Thrombotic occlusion of both posterior cerebral arteries occurred during embolization of an acutely ruptured basilar tip aneurysm. Intracranial stenting and continuous superselective infusion of rtPA was administered combined with mechanical clot fragmentation to reestablish normal vessel flow. DSA disclosed that normal vessel patency was achieved within 30 min. There were no adverse events related to rtPA administration and the patient recovered from the embolization with minor neurologic deficit as present before the procedure.

Activation-independent platelet adhesion and aggregation under elevated shear stress

AbstractPlatelet aggregation, which contributes to bleeding arrest and also to thrombovascular disorders, is thought to initiate after signaling-induced activation. We found that this paradigm does not apply under blood flow conditions comparable to those existing in stenotic coronary arteries. Platelets interacting with immobilized von Willebrand factor (VWF) aggregate independently of activation when soluble VWF is present and the shear rate exceeds 10 000 s–1 (shear stress = 400 dyn/cm2). Above this threshold, active A1 domains become exposed in soluble VWF multimers and can bind to glycoprotein Ibα, promoting additional platelet recruitment. Aggregates thus formed are unstable until the shear rate approaches 20 000 s–1 (shear stress = 800 dyn/cm.2). Above this threshold, adherent platelets at the interface of surface-immobilized and membrane-bound VWF are stretched into elongated structures and become the core of aggregates that can persist on the surface for minutes. When isolated dimeric A1 domain is present instead of native VWF multimers, activation-independent platelet aggregation occurs without requiring shear stress above a threshold level, but aggregates never become firmly attached to the surface and progressively disaggregate as shear rate exceeds 6000 s–1. Platelet and VWF modulation by hydrodynamic force is a mechanism for activation-independent aggregation that may support thrombotic arterial occlusion.

Enhanced spontaneous thrombolysis: A new therapeutic challenge

Spontaneous thrombolysis is an endogenous protective mechanism against lasting arterial thrombotic occlusion, which is implicated in the pathogenesis of myocardial infarction and acute coronary events. Novel therapies for coronary heart disease (CHD) targeting atherosclerosis and thrombosis, together with cardiovascular prevention programs targeting risk-factors and lifestyle provide evidence that CHD is preventable. Although reduced fibrinolytic activity is a recognized risk-factor for ischemic cardiovascular events, it has so far been neglected. Our knowledge of the fibrinolytic effect of drugs commonly used for CHD such as antiplatelet agents (aspirin, ticlopidine, clopidogrel), anti-diabetic biguanides (phenformin, metformin) or anti-hypertensive drugs is scanty and conflicting. This is mainly due to the lack of a global test of spontaneous thrombolysis, as opposed to fibrinolysis of plasma or whole blood, i.e. the assessment of various activators and inhibitors of the fibrinolytic system. A recently described technique allows the measurement of spontaneous thrombolysis, that is, lysis of an autologous platelet-rich thrombus in the absence of added plasminogen activators. Early results suggest that this test may have significant clinical potential both in identifying those at risk of fatal cardiac events and in finding new therapeutic avenues or lifestyles to improve spontaneous thrombolytic activity.

Virtual histology and the hunt for the vulnerable plaque

It is a generally accepted concept that acute thrombotic coronary artery occlusion occurs at the site of a vulnerable plaque (VP). Three different types of histopathological entities have been described in coronary arteries from victims of sudden death related to coronary artery disease: (i) plaque rupture, (ii) plaque erosion, and (iii) calcified nodule.1 A ruptured plaque consists of a necrotic core (NC) with ruptured overlying thin fibrous cap. In plaque erosion, there is a luminal thrombus with proteoglycans and smooth muscle cells and minimal inflammation in the vessel wall. NC is absent or covered with a thick fibrous cap. The calcified nodule consists of depot of calcifications with discontinuation of the fibrous cap and the absence of endothelium. In autopsy studies on cases of sudden death, thrombi related to the above changes have been seen in 60, 30–35, and 2–7% of the cases.1 The pathological studies indicate that prior to plaque rupture with thrombosis, the plaque was an inflamed, thin cap fibroatheroma (TCFA) or a VP resembling a ruptured plaque without the rupture itself.2 It would be highly desirable to be able to detect a suspected VP before it causes thrombosis and acute myocardial infarction (AMI). The latest technology developed for this purpose is spectral analysis of intravascular ultrasound (IVUS) radio frequency data. This technique has improved the tissue characterization in coronary artery disease to a degree that it is called virtual histology (VH), as it has been found to have a very close correlation with histopathological findings from cadaver arteries.3 In the … Corresponding author. Tel: +45 35453396; fax: +45 35452705. E-mail address : kari.saunamaki{at}rh.hosp.dk

Markers of inflammation in acute coronary syndromes: Association with increased heart rate and reductions in heart rate variability

Systemic and vascular inflammation is at the heart of the thrombotic occlusion of coronary arteries. The study was undertaken to determine the relationship between established inflammatory markers (interleukin-6 [IL-6] and high-sensitivity C-reactive protein [hs-CRP]), neutrophil or white cell count, and concomitant autonomic tone in patients with coronary artery disease soon after occlusive events. We tested the linkage between autonomic tone (as defined using both time domain and frequency domain estimates of heart rate variability [HRV]) and circulating markers of inflammation (white cell counts, hs-CRP, and IL-6) in a sample of 100 patients with proven acute coronary syndrome and compared these with healthy controls (n = 49) and the relationships on repeated measures at 4 months in recovery (n = 51). We demonstrated predictable depressed HRV in acute patients who tended to show recovery by 4 months. The acute changes in HRV indices (e.g., triangular index) showed modest negative correlation (r = -0.2-0.3) with the acute elevation of white cell count, IL-6, and hs-CRP. These associations did not persist on multivariate analysis of data gathered at 4 months post event. These observational data, while limited, are the first to link autonomic tone and in particular sympathetic tone (as indicated by HRV), to the process of acute leukocytosis and systemic inflammation common in acute coronary syndromes.

Tumor necrosis factor-alpha gene ???308G&gt;A polymorphism is associated with ST-elevation myocardial infarction and with high plasma levels of biochemical ischemia markers

As is well known, acute myocardial infarction presents two electrocardiogram (EKG) patterns, ST-elevation (STEMI) and no ST-elevation (NSTEMI), characterized by different coronary artery thrombotic occlusion. Growing evidence shows that inflammation plays a central role in the pathogenesis of acute myocardial infarction. Among the factors that promote inflammation and arterial thrombosis, one of the most important is the proinflammatory cytokine tumor necrosis factor-alpha. The expression of this cytokine is modulated by a polymorphism located at nucleotide -308 of tumor necrosis factor-alpha promoter gene. The objective of our study is to verify whether tumor necrosis factor-alpha -308 polymorphism is associated with risk of acute myocardial infarction (STEMI and NSTEMI) or with biochemical myocardial ischemia markers, such as troponin I, creatine kinase-MB, lactate dehydrogenase and myoglobin. We analyzed tumor necrosis factor-alpha -308 polymorphism in a total of 603 study participants: 293 elderly patients affected by acute myocardial infarction (STEMI and NSTEMI) and 310 healthy controls. We found that individuals carrying the tumor necrosis factor-alpha -308 AG+AA genotypes are significantly more represented among acute myocardial infarction patients affected by STEMI than among NSTEMI patients (OR = 1.86, 95% CI 1.08-3.21, p = 0.027) and healthy controls (OR = 1.64, 95% CI 1.03-2.64, p = 0.046). Furthermore, the patients carrying tumor necrosis factor-alpha -308 AG+AA genotypes displayed significant increased levels of biochemical myocardial ischemia markers. Our study shows a significant association between the tumor necrosis factor-alpha -308 polymorphism and the occurrence of STEMI, and suggests that the tumor necrosis factor-alpha -308 polymorphism could play a role in the pathogenesis of cardiac ischemic damage, AA+AG genotype carrier individuals being likely to be affected by more severe ischemic damage than the rest of the population.

Fatal eosinophilic heart disease in a child with neurofibromatosis-1 complicated by acute lymphoblastic leukemia

We present a pediatric case of neurofibromatosis-1 (NF-1) complicated by acute lymphoblastic leukemia and hypereosinophilia, which caused multiple end-organ damage. Although clinical symptoms such as fever and coughing were noted only 1 week before admission, the condition deteriorated rapidly with a fatal outcome prior to antileukemic therapy. A postmortem examination demonstrated extensive endomyocardial fibrosis with thrombotic occlusion and recanalization of the coronary arteries. Leukemic cell infiltration was not seen in the cardiac tissue. When eosinophilia is diagnosed in patients with NF-1, eosinophilic end-organ damage, particularly cardiac involvement, in addition to hematological malignancies, should be screened for in order to start medical treatment at the early stage of the disease.

Systemische fibrinolytische Therapie mit Urokinase bei Zentralarterienverschluss der Netzhaut

Systemic fibrinolysis has become an important therapeutical option in patients with thrombotic occlusion of coronary or pulmonary arteries. In view of the hemorrhagic risk systemic fibrinolytic therapy for retinal vessel occlusion has been discussed controversial. In the present case study results and complications of systemic fibrinolysis should be investigated in patients with central retinal artery occlusion.From 1995 to 2002 a case series of 19 consecutive patients (8 female, 11 male, age: 63.2+/-14,3 years) with central retinal artery occlusion were treated by systemic application of urokinase using a standardized scheme. The latency from initial symptoms until the initiation of therapy and the medical history of the patients were documented. Visual acuity was determined on admission and before discharge and possible complications were documented. Additionally, screening investigations for genetic thrombophilia were performed.15 patients showed an improvement of the visual acuity (79 %, 95 %-KI: 54 %-94 %). For 3 patients no improvement and for one patient a decrease of the visual acuity was determined. Hemorrhagic complications were observed in two patients (11 %, 95 %-KI: 1 %-33 %). As these minor bleedings were self-limiting the fibrinolytic therapy was discontinued only in one patient. As risk factors most commonly arterial hypertension (68 %) and smoking (26 %) were identified. In 4 patients a genetic thrombophilia was diagnosed.Considering the poor prognosis of central retinal artery occlusion and the disappointing results of conservative treatment, an improvement of the visual acuity in the absence of critical complications was observed with systemic fibrinolytic therapy in the presented case study. However, only controlled trials can provide proof for the effect of fibrinolysis versus spontaneous improvement.

Selektive intraarterielle Lysetherapie bei neonatalem Arteria-axillaris-Verschluss: Angiographische und thermographische Verlaufskontrolle

Arterial thrombotic vascular occlusions in the neonatal period are rare. Intraarterial thrombolytic therapy in infants and children is unchanged rarely used but can be very effective. Thrombolytic therapy in adults is well established and a summary of clinical and pharmacologic aspects exists of different thrombolytic agents. Recombinant-Tissue-Plasminogen-Activator (rTPA) is increasingly used in thrombolytic therapy in infants and children in the last years. We report thrombolysis of axillar arterial thrombosis with rTPA in a premature infant. Additional thermographic images were performed, which were very helpful in the clinical monitoring of the newborn.

FK419, a Novel Nonpeptide GPIIb/IIIa Antagonist, Restores Microvascular Patency and Improves Outcome in the Guinea-Pig Middle Cerebral Artery Thrombotic Occlusion Model: Comparison with Tirofiban

The antithrombotic efficacy of FK419, a novel nonpeptide platelet glycoprotein IIb/IIIa antagonist, was compared with tirofiban in guinea-pigs. FK419 and tirofiban similarly inhibited platelet aggregation in vitro (IC50 values: 0.43+/-0.076 and 0.41+/-0.053 micromol/L) and dispersed aggregated platelets (EC50 values: 2.3+/-0.88 and 2.0+/-0.81 micromol/L). FK419 inhibited retention of platelets and neutrophils in a collagen-coated bead column with greater potency than tirofiban (IC50 values of 0.90+/-0.133 and 2.4+/-0.21 micromol/L for platelet retention and 0.32+/-0.078 and 0.57+/-0.180 micromol/L for neutrophil retention). When FK419 or tirofiban were administered after photochemically induced middle cerebral artery (MCA) occlusion in guinea-pigs, they dose-dependently improved MCA patency. FK419 reduced neurological deficits and ischemic brain damage in a dose-dependent fashion, whereas tirofiban did not. Reduced regional cerebral blood flow in the striatum gradually returned to the preoccluded level with FK419 treatment; however, no restoration was observed with tirofiban even though the MCA was recanalized. These results indicate that FK419 ameliorates ischemic brain damage by not only lysing the obstructive thrombus in MCA but also preventing or restoring microcirculation deficits after occlusion/reperfusion, suggesting that FK419 would be an attractive intervention for the treatment of ischemic stroke patients.