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

The most commonly recognized cause of mesenteric venous thrombosis following splenectomy is hypercoagulation secondary to reactive thrombocytosis. A case is reviewed in which hypercoagulation followed splenectomy for idiopathic thrombocytopenic purpura (ITP) in spite of persistent thrombocytopenia. Episodic mesenteric venous occlusion occurred due to antithrombin III deficiency. This hypercoagulable state may be the cause of primary acute mesenteric venous occlusive disease. Symptoms and signs suggesting thrombosis in the portal circulation demand immediate coagulation studies since even in the thrombocytopenic patient thrombotic proglems can occur. Surgical intervention is the treatment of choice for segmental small bowel ischemia; warfarin therapy is indicated when there is evidence of antithrombin III deficiency.
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PMID:Antithrombin III deficiency causing postsplenectomy mesenteric venous thrombosis coincident with thrombocytopenia. 6 57

Heparin sodium-induced thrombosis is insidious and difficult to diagnose. If untreated, it results in death or major amputation. We have treated seven patients with thromboses resulting from platelet aggregation induced by heparin. Four patients had acute arterial ischemia of the lower extremity, venous gangrene developed in two, and one patient had an occluded autogenous vein femoral popliteal bypass in the immediate postoperative period. The platelet count was noticeably reduced in affected patients. White platelet thrombi were noted in four patients, three of whom had acute arterial occlusion. A white thrombus was the cause of immediate failure of a femoral popliteal graft. Electron microscopic examination of these thrombi demonstrated predominantly fibrin platelet aggregates with an occasional entrapped WBC and a rare RBC. All patients receiving heparin therapy must have platelet counts performed regularly. If thrombocytopenia is detected, platelet aggregation studies are indicated. When abnormal platelet aggregation is noted, heparin therapy should be reversed with protamine sulfate and the patient treated with low-molecular-weight dextran and warfarin sodium.
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PMID:White clot syndrome. Peripheral vascular complications of heparin therapy. 43 52

Thrombotic complications of heparin administration were observed in eight patients during a two year period. At sites of subcutaneous heparin injection, six patients developed areas of the skin and subcutaneous necrosis. Systemic thrombotic events and thrombocytopenia were observed in two of these patients when they received intravenous heparin and in two other patients who did not have primary skin necrosis. The complications included peripheral ischemia in three patients (two requiring amputation), myocardial infarction in two, and a cerebral infarction in one. All patients were receiving heparin for at least six days before complications occurred. Seven patients received heparin of bovine origin. Heparin-induced in vitro platelet aggregation was present in all six of the eight patients tested. (It was marked in four of these patients). It is theorized that skin necrosis and the other thrombotic complications observed are the result of heparin-induced in vivo platelet aggregation followed by intravascular thrombosis. Heparin-induced skin necrosis is a rare but serious hazard encountered with prophylactic heparin regimens. If heparin-induced thrombosis is present, the further use of heparin is contraindicated in most instances.
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PMID:Thrombotic complications of heparin therapy: including six cases of heparin--induced skin necrosis. 50 70

Arterial thromboembolism is a recognized complication of systemic heparin therapy. Characteristic of the entity is arterial occlusion by platelet-fibrin thrombi with distal ischemia occurring four to twenty days after the initiation of heparin therapy, preceded by profound thrombocytopenia with platelet counts in the range of 30,000 to 40,000 per cubic millimeter. The clinically apparent occlusion may be preceded by gastrointestinal and musculoskeletal symptoms that appear to be ischemic in origin, and might serve to warn the clinician of these complications. Previous reports of these phenomena as well as recent studies of the effect of heparin are reviewed. The common factor relating thromboembolism and thrombocytopenia is heparin-induced platelet aggregation. Appropriate treatment consists of discontinuation of heparin, and anticoagulation with sodium warfarin if necessary. Vascular procedures are performed as indicated.
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PMID:Arterial thromboembolism in patients receiving systemic heparin therapy: a complication associated with heparin-induced thrombocytopenia. 59 36

Coagulation mechanisms were examined in the dog after a 70 per cent hepatectomy and the additional effect of varying periods of ischemia on the liver remnant. Dogs were submitted to a 70 per cent partial hepatectomy, and the liver remnant was rendered ischemic by occluding the vascular inflow. Portal decompression during ischemia was accomplished by allowing portal venous flow through the lobes subsequently resected. Dogs in the control group, those undergoing hepatectomy alone and those undergoing hepatectomy together with 60 minutes of ischemia time exhibited a fall in hemoglobin and hematocrit values, a transient leukocytosis, a small increase in kaolincephalin clotting time and a decline in platelet count but no significant thrombocytopenia. Prothrombin time was changed in dogs undergoing hepatectomy, but this was not affected by ischemia. The characteristic rise in plasma fibrinogen postoperatively was abolished, and fibrinogen levels were lower in dogs undergoing hepatectomy alone and fell significantly in dogs subjected to 30 to 60 minutes of ischemia of the liver remnant. Factors V and VII were decreased after hepatectomy, and Factor V was more severely reduced after 30 to 60 minutes of ischemia. There was no overt bleeding tendency. In ten dogs, the liver remnant was subjected to ischemia for 75 minutes. Four of these died within three days of operation, two with severe hypoglycemia and two with postoperative bleeding. All six surviving dogs exhibited gross coagulation defects. Prothrombin time rose, kaolin-cephalin clotting time increased and platelets fell to a greater degree than in any of the other dogs. Plasma fibrinogen level showed a profound fall, as did Factor V, the magnitude of these changes being greater than after a shorter period of ischemia. Factor VII was also decreased, but this did not appear to be related to the ischemic interval. In the clinical situation in which intrinsic coagulation mechanisms are shown to be impaired, treatment with Factor V and VII concentrates may be the best way of correcting the coagulation defect.
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PMID:The mechanism of impaired coagulation after partial hepatectomy in the dog. 93 55

The authors report 2 cases of unilateral cerebellar atrophia presenting in the neonatal period with facial peripheral palsy and iso-immune thrombocytopenia respectively. The recognition of cerebellar atrophia has been made by MRI. Unilateral cerebellar atrophia be due to ischemia. MRI seems to be a useful tool in the recognition of cerebellar malformations in the neonatal period.
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PMID:[Unilateral cerebellar atrophy in 2 newborn infants. Value of MRI]. 155 Apr 51

Liver transplant is the first therapeutic choice in most of the advanced liver diseases. Nevertheless, its performance originates a number of complications derived from: a) conservation techniques of the organ (in our study a prolonged time of hot ischemia was significantly associated with); b) surgery (all patients who required massive blood transfusions developed metabolic alkalosis); c) the graft itself (all the F 1. degrees were significantly infected), and d) extrahepatic causes (cyclosporin was responsible for high blood pressure and nephrotoxicity which appeared as oliguria with good response to furosemide, as well as hyperglycemia). Some other relevant results in our series were: right pleural effusion and thrombopenia which appeared with a high incidence. Infections were usually originated the staphylococcus which grows in half of the cultures. We also want to highlight the short mean stay and the low mortality incidence in the ICU.
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PMID:[Complications of liver transplant in intensive care. Experience in 130 cases]. 176 10

To determine which therapeutic procedure is most appropriate for which type of aortic dissection, we investigated 146 cases of acute aortic dissection. In the group with dissection of the ascending aorta, 58.6% of patients given medical therapy and 48.8% of patients given surgical therapy died. In the group with dissection of the descending aorta, 14.0% given medical therapy and 50.0% given surgical therapy died. High mortality in the medical group with type A dissection was caused by delayed operation. Better survival was achieved in treated than surgically treated patients with acute distal dissection. In patients with cardiac tamponade, aortic regurgitation, hemothorax/hemo-mediastinum, visceral ischemia and peripheral ischemia, mortalities following medical treatment were fairly high. Surgical treatment brought on improvement in mortality in these groups. However, in the cases complicated by renal dysfunction, the mortality in the surgical group was higher than that in the medical group. 42 patients (28.8%) had no evidence of any complication and only 6 (14.3%) died. In 20 cases (47.6%) of uncomplicated dissection, no blood flow was observed in the false lumen. In cases with open false lumen, the following abnormal findings were more conspicuous: thrombocytopenia, decreased level of fibrinogen, increased fibrin degradation product and soluble fibrin monomer complex. However, these changes seem to be minimal in cases with thrombosed false lumen. The measurement of coagulation factors may be one useful method to determine which therapeutic procedure is most suitable.
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PMID:Medical vs surgical treatment of acute aortic dissection in an intensive care unit. 189 14

In order to clarify the role of platelets as a factor aggravating cerebral ischemia, an experimental model of ischemia was investigated using thrombocytopenic rats. In addition, the prostacyclin derivative (OP-41483) and the thromboxane A2 synthetase inhibitor (OKY-046), both of which inhibit platelet aggregation, were tested for possible beneficial effects on cerebral ischemia. Cerebral ischemia was produced in spontaneously hypertensive male rats using bilateral common carotid artery ligation (BLCL). Thrombocytopenia was produced with an antiplatelet antiserum which reduced the platelet count to less than 6 x 10(4)/microliters by 24 h. OP-41483 was administered four times hourly (500 ng/kg x 4, i.p.), beginning 1 h prior to BLCL. Similarly, OKY-046 was injected four times hourly (10 mg/kg x 4, i.p.). Brain metabolites such as ATP, lactate and pyruvate and water content were determined after 3 h of cerebral ischemia. Brain levels of ATP in the ischemic rats with thrombocytopenia were higher than those of the ischemic rats without thrombocytopenia. In addition, thrombocytopenia reduced the increase of lactate and water content in the ischemic brain. Animals treated with OP-41483 also maintained higher levels of ATP and lower levels of lactate and water compared to animals given a vehicle. OKY-046 significantly reduced brain water content, but had no effect on the ischemic alteration of brain metabolite levels. These results indicate that platelets play an important role in the progression of metabolic change during ischemia.
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PMID:Role of platelets as a factor aggravating cerebral ischemia. 207 48

The authors report 21 cases of heparin-induced thrombocytopenia with ischemic vascular complications. The clinical presentations were peripheral arterial ischemia (16 cases), hemiplegia (1 case) and deep vein thrombosis (4 cases). The vascular surgeon confronted by these complications in an emergency situation should recognise the difficulties of clinical diagnosis (atypical forms) and biological investigations (problems of tests of platelet aggregation). Arterial occlusions are usually accessible to disobliteration with a Fogarty catheter without peroperative heparinisation. Delayed diagnosis explains the seriousness of these complications; in our series of 21 patients, there were 2 deaths, 1 paraplegia, 4 amputations due to arterial problems, 4 severe post-deep vein thrombosis conditions, two of which followed trans-metatarsal amputation. The diagnosis of heparin-induced thrombocytopenia implies immediate withdrawal of heparin therapy. A relay with a low molecular weight heparin is not without risk and should only be undertaken after a negative platelet aggregation test (with the low molecular weight heparin). These tests are rarely practicable in emergency situations and a relay using oral anti-vitamin K antagonists with a rapid onset of action is probably the safest option.
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PMID:[Ischemic vascular complications following thrombopenia induced by heparin. Diagnostic and therapeutic problems]. 212 62


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