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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tissue factor pathway of coagulation plays a dominant role during normal haemostasis. Tissue factor pathway inhibitor (TFPI), expressed primarily by the microvascular endothelium, appears to be the major physiologic inhibitor of TF-induced coagulation. TF-initiated coagulation also plays an important role in the pathophysiology of many diseases including coronary thrombosis, sepsis, disseminated intravascular coagulation, stroke, cancer, acute respiratory distress syndrome, and ischemia-reperfusion injury. Several animal studies have found a beneficial effect of anti-TF monoclonal antibodies and, recombinant TFPI in some of the above clinical conditions. rTFPI is presently being used in clinical trials in patients with sepsis and in those following microvascular surgery. This article discusses many of the animal studies addressing inhibition of TF-induced coagulation, as well as potential therapeutic uses of rTFPI in humans.
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PMID:Tissue factor pathway inhibitor: potential therapeutic applications. 919 99

Emergent percutaneous transluminal coronary angioplasty (PTCA) is an effective treatment for acute myocardial infarction. However, occasionally results of angioplasty are suboptimal due to coronary dissection or elastic recoil, leading to a high chance of recurrent ischemia. Coronary stents are occasionally employed in such settings, but a high incidence of stent thrombosis was noted by early investigators when stents were placed into areas of active thrombus formation. Since coronary thrombosis and stent thrombosis are both initiated by platelets, the potent antiplatelet agent abciximab might be useful in preventing stent thrombosis. Little information is available concerning early outcome or 6-month clinical event rate when coronary artery stents are placed for suboptimal angioplasty results for acute myocardial infarction in patients given abciximab. We deployed 75 stents as part of angioplasty for acute myocardial infarction in 40 patients given abciximab. All patients had suboptimal angioplasty results leading to stent deployment. Each obtained normal flow angiographically and no stent thrombosis or acute closure was observed. Early mortality occurred in 1 patient. All patients were followed at least 6 months, and no patient died after hospital discharge. Three patients experienced recurrent ischemic events within the first 6 months. Two of these events were due to infarct vessel restenosis. We conclude the combined use of coronary artery stents and abciximab for suboptimal PTCA results during acute myocardial infarction is associated with a low incidence of culprit vessel recurrent ischemic events within 6 months of intervention.
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PMID:Coronary artery stenting for suboptimal PTCA results in acute myocardial infarction in patients treated with Abciximab: early and six-month outcome. 937 47

Patients who present today with an acute coronary syndrome face a substantially lower risk of death, recurrent myocardial infarction, or severe ischemia than patients did a decade ago. Researchers are pursuing new strategies to further improve the outcomes of patients with acute coronary syndromes. These strategies may be grouped into 3 paradigms: (1) restoration and maintenance of coronary flow at the site of culprit lesion; (2) reduction of infarct size, reperfusion injury, and postischemic dysfunction; (3) stabilization of the coronary arterial wall and its interaction with the bloodstream to reduce recurrent ischemic events. The last approach encompasses strategies to alter the underlying vascular pathophysiology that leads to plaque instability and coronary thrombosis. Investigation into each of these paradigms may yield new strategies that will be incorporated into standard clinical management of acute coronary syndromes in coming years. With so many mechanistically different approaches to the management of acute coronary syndromes, clinicians have reason for optimism that continued progress will further reduce the morbidity and mortality associated with acute coronary syndromes and the likelihood of their recurrence.
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PMID:Exploring new strategies for the management of acute coronary syndromes. 1108 48

Patients with polycethemia vera (PV) or essential thrombocythemia (ET) are at increased risk of arterial and venous thromboembolic events. Arterial ischemic complications occur in 24 to 43% of these patients, particularly those with cardiovascular risk factors (especially cigarette smoking). Non-atheromatous arterial thrombosis concerns all large and medium-sized vessels, particularly cerebral, limb, coronary and digestive arteries. Extensive complications have been described in patients with lower limb occlusive arteriopathy, particularly stent or bypass thrombosis, critical ischemia. Juvenile myocardial infarction or rapid postangioplasty coronary thrombosis may reveal certain myeloproliferative disorders, particularly ET. Venous thrombosis is more frequent in PV than in ET; superficial or deep venous thromboses are seen. Thromboembolic events occur in about 25-30% of the patients and account for one-third of the deaths. Mesenteric vein thrombosis, portal thrombosis, or suprahepatic vein thrombosis may occur in all myeloproliferative disorders, but the pathogenesis is not fully understood. Pulmonary hypertension may be the consequence of local thrombosis in the pulmonary vasculature or may be due to the high blood flow in the right heart cavities. Microvascular circulatory disturbance includes erythromelalgia, Raynaud's phenomenon, digital ischemia, acrocyanosis, blue toe syndrome, livedo reticularis, cutaneous ulcers or necrotic purpura. All these manifestations may precede the myeloproliferative disorder by several months.
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PMID:[What vascular events suggest a myeloproliferative disorder?]. 1114 2

We have previously shown that atherosclerotic apolipoprotein E-deficient (apoE(-/-)) x LDL receptor-deficient (LDLR(-/-)) mice develop myocardial infarction when exposed to hypoxic stress. This study was performed to assess the role of thrombin and thrombosis in this process. ApoE(-/-) x LDLR(-/-) mice were fed a cholesterol-rich diet for 8 mo and were then subjected to hypoxic stress while receiving isoflurane anesthesia. One group received a bolus dose (5.6 micromol/kg) of the thrombin inhibitor melagatran, and control animals received PBS 10 min before the hypoxic stress. The mice were exposed to 10 min of hypoxia followed by normoxia. Ten minutes after the stress, Alzet pumps delivering melagatran (20 nmol x kg x (-1)min(-1)) or PBS were implanted, and the mice were allowed to recover for 48 h. The cardiac response was analyzed by histology, immunohistochemistry, and serum troponin T assay. All animals showed reversible ECG changes as a sign of ischemia during hypoxic stress, and 50% developed infarctions afterward as judged by troponin T levels. The group that received thrombin inhibitor had significantly lower troponin T and smaller myocardial infarctions than the PBS-treated group. These data show that thrombin generation is an important pathogenetic factor and suggest that coronary thrombosis is involved in myocardial infarction in atherosclerotic mice. Exposure of atherosclerotic mice to hypoxia leads to myocardial infarction through a two-phase pathway in which acute transient ischemia is followed by thrombin-dependent, irreversible, myocardial ischemia and myocardial cell death.
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PMID:Thrombin inhibitor reduces myocardial infarction in apoE-/- x LDLR-/- mice. 1503 Nov 24

Panic disorder serves as a clinical model for testing whether mental stress can cause heart disease. Our own cardiologic management of panic disorder provides case material of recurrent emergency room attendances with angina and electrocardiogram ischemia, triggered arrhythmias (atrial fibrillation, ventricular fibrillation), and documented coronary artery spasm, in some cases with coronary spasm being complicated by coronary thrombosis. Application of radiotracer catecholamine kinetics and clinical microneurography methodology suggests there is a genetic predisposition to panic disorder that involves faulty neuronal norepinephrine uptake, possibly sensitizing the heart to symptom generation. During panic attacks there are large sympathetic bursts, recorded by clinical microneurography in the muscle sympathetic nerve neurogram, and large increases in cardiac norepinephrine spillover, accompanied by surges of adrenal medullary epinephrine secretion. In other conditions such as heart failure and presumably here also, a high level of sympathetic nervous activation can mediate increased cardiac risk. The sympathetic nerve cotransmitter, neuropeptide Y (NPY), is released from the cardiac sympathetics during panic attacks, an intriguing finding given that NPY can cause coronary artery spasm. There is ongoing, continuous release of epinephrine from the heart in panic sufferers, perhaps attributable to epinephrine loading of cardiac sympathetic nerves by uptake from plasma during panic attacks, or possibly to in situ synthesis of epinephrine through the action of intracardiac phenylethanolamine-N-methytransferase (PNMT) activated by repeated cortisol responses. We have used internal jugular venous sampling and measurement of overflowing lipophilic brain monoamine metabolites to quantify brain norepinephrine and serotonin turnover in untreated patients with panic disorder. We find normal norepinephrine turnover but a marked increase in brain serotonin turnover in patients with panic disorder, in the absence of a panic attack, which presumably represents an underlying neurotransmitter substrate for the condition.
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PMID:Cardiac sympathetic nerve biology and brain monoamine turnover in panic disorder. 1524 Apr 8

Intimal thickening, the accumulation of cells and extracellular matrix within the inner vessel wall, is a physiological response to mechanical injury, increased wall stress, or chemical insult (e.g., atherosclerosis). If excessive, it can lead to the obstruction of blood flow and tissue ischemia. Together with expansive or constrictive remodeling, the extent of intimal expansion determines final lumen size and vessel wall thickness. Plaque rupture represents a failure of intimal remodeling, where the fibrous cap overlying an atheromatous core of lipid undergoes catastrophic mechanical breakdown. Plaque rupture promotes coronary thrombosis and myocardial infarction, the most prevalent cause of premature death in advanced societies. The matrix metalloproteinases (MMPs) can act together to degrade the major components of the vascular extracellular matrix. All cells present in the normal and diseased blood vessel wall upregulate and activate MMPs in a multistep fashion driven in part by soluble cytokines and cell-cell interactions. Activation of MMP proforms requires other MMPs or other classes of protease. MMP activation contributes to intimal growth and vessel wall remodeling in response to injury, most notably by promoting migration of vascular smooth muscle cells. A broader spectrum and/or higher level of MMP activation, especially associated with inflammation, could contribute to pathological matrix destruction and plaque rupture. Inhibiting the activity of specific MMPs or preventing their upregulation could ameliorate intimal thickening and prevent myocardial infarction.
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PMID:Dual role of matrix metalloproteinases (matrixins) in intimal thickening and atherosclerotic plaque rupture. 1561 76

This study examines the cardioprotective effects of Na+/H+ exchange inhibition with BIIB-722 or ischemic preconditioning after occlusive thrombus formation and subsequent thrombolysis for reperfusion. Coronary artery thrombosis was induced by vessel wall electrolytic injury. Thrombotic occlusion was maintained for 60 or 90 min in 4 different groups: (1) control; (2) Na+/H+ exchange inhibitor, BIIB-722 (3 mg/kg) before occlusion; (3) BIIB-722 (0.75 mg/kg) before reperfusion; (4) ischemic preconditioning (4 x 5 min). Thrombolysis with intracoronary recombinant tissue plasminogen activator produced reperfusion in 6.3 +/- 1.4 min (average for 68 dogs). After restoration of blood flow, vessel patency was maintained for 4 h with the glycoprotein IIb/IIIa receptor antagonist, BIBU 52ZW. BIIB-722, administered before (26.9 +/- 3.6%) or after (22.0 +/- 2.3%) 60-min ischemia or preconditioning (18.4 +/- 2.8%), produced comparable and significant reductions in infarct size (percent of area at risk) compared to controls (47.2 +/- 2.0%). After 90 min of ischemia, BIIB-722 administered before occlusion (37.3 +/- 1.1%) and ischemic preconditioning (35.0 +/- 4.8%) provided significant cardioprotection compared to control (45.9 +/- 1.8%). BIIB-722 was not cardioprotective when administered during occlusion (48.0 +/- 2.4%). The results indicate that Na+/H+ exchange inhibition and preconditioning provide a comparable degree of cardioprotection against 60 min of regional ischemia. However, when the regional ischemic period is extended to 90 min, the degree of cardioprotection is markedly reduced. Further studies incorporating clinically relevant events such as thrombosis and thrombolysis are required before one can conclude that Na+/H+ exchange inhibition is effective against more prolonged myocardial ischemia.
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PMID:Effect of sodium/hydrogen exchange inhibition on myocardial infarct size after coronary artery thrombosis and thrombolysis. 1689 91

The specific thromboxane receptor antagonist, S18886, was evaluated for prevention of coronary arterial thrombosis and myocardial ischemia-reperfusion in anesthetized canines. For the primary thrombosis study in left circumflex (LCX) coronary artery, 26 dogs were randomized to receive either vehicle (n = 7) or intravenous S18886 (0.3 mg/kg, n = 6; 1.0 mg/kg, n = 6; and 3.0 mg/kg, n = 7). The respective times to occlusion after S18886 were as follows: 56.8 +/- 9.3, 83.5 +/- 14.9, and 92.4 +/- 15.7 minutes compared to 43.3 +/- 8.2 minutes after vehicle. S18886 caused a minimal increase in tongue bleeding time and a significant decrease in ex vivo platelet aggregation to arachidonic acid or U46619. Another 37 dogs were randomized to receive placebo (n = 12), clopidogrel 1.0 mg/kg p.o. QDX3 (n = 9), clopidogrel + S18886 0.3 (n = 9) or 1.0 (n = 7) mg/kg intravenous. Clopidogrel produced a 50% reduction in adenosine diphosphate-induced platelet aggregation and a slight increase in the time to occlusion. However, clopidogrel + S18886 1.0 mg/kg prevented occlusive thrombus formation in most of the coronary vessels over 6 hours. S18886 did not alter myocardial infarct size in the ischemia-reperfusion model. In conclusion, S18886 alone caused a dose-dependent prolongation in the time to primary occlusive coronary artery thrombosis, whereas S18886 + clopidogrel displayed effective in preventing occlusive thrombus formation with only a moderate increase of tongue-bleeding time.
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PMID:Preclinical evaluation of S18886 in an experimental model of coronary arterial thrombosis. 1711 Aug 6

Patients with coronary artery aneurysms caused by Kawasaki disease are at increased risk of coronary thrombosis and ischemia. To prevent coronary thrombosis, long-term anti-thrombosis using anti-platelet drugs, such as aspirin, dipyridamole, ticlopidine, clopidogrel, and abciximab, with or without warfarin is recommended by official guidelines. In fact, aspirin or aspirin with warfarin are the most frequently administered regimen in these patients with coronary aneurysms. However, there has been paucity of data and no randomized controlled study to determine the efficacy of these drugs. This short article attempts to summarize the efficacy and safety of these drugs based on currently available literatures and our multi-institutional experience.
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PMID:[Prevention of thrombosis of coronary aneurysms in patients with a history of Kawasaki disease]. 1826 59


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