Hemostatic abnormalities associated with dysproteinemias.
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It is estimated that 5% of patients with deep vein thrombosis and 50% of those with recurrent thrombosis have an inherited abnormality of coagulation, most commonly deficiency of protein C, protein S or antithrombin III. These disorders should be suspected when venous thrombosis occurs in a young person, if there is a family history of thrombosis, if thrombosis occurs at an unusual site or if there is recurrent thrombosis with no predisposing factors. Affected patients are treated with lifelong anticoagulation therapy. Thromboembolism and its sequelae often produce abnormal findings on radiologic examinations, and therefore the radiologist who is familiar with these abnormalities is in a position to be the first to suggest the diagnosis.
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We report 2 cases of portal vein thrombosis associated with a single point mutation in the factor V gene that replaces arginine in residue 506 with glutamine. This mutation induces abnormal resistance to anticoagulant activity of activated protein C and increases the risk of deep vein thrombosis. Both patients had a personal and familial history of deep vein thrombosis. Intraabdominal neoplasia or infection, myeloproliferative disorder, antiphospholipid syndrome, paroxysmal nocturnal hemoglobinuria and coagulation inhibitor deficiency (antithrombin, proteins C and S) were excluded by exhaustive investigation. However, an abnormal resistance to activated protein C was found, and DNA analysis showed the factor V Arg506 to Gln mutation in both cases. Anticoagulant treatment was begun. A study of family history made in one case, showed the same genetic disease in one of the relatives. Resistance to activated protein C with factor V gene mutation should be investigated in patients with portal vein thrombosis. A study of family history, and anticoagulant treatment are justified for symptomatic patients.
Protein C deficiency is a disorder in the coagulation cascade that results in predominantly venous thromboembolism. However, recent studies have implicated this disorder as a possible contributor to arterial thrombosis, especially myocardial infarction. There are six reported cases of myocardial infarction secondary to protein C deficiency in the literature. This is the first report of myocardial infarction and ischaemic stroke in the same patient as a manifestation of protein C deficiency. The investigation of hypercoagulable state is an essential component of the investigation of young patients with myocardial infarction.
Discordant liver xenotransplantation is a poorly explored entity. Data from the few large animal studies of hepatic xenotransplantation suggest that severe hemorrhage is encountered. The purpose of the studies described here is to characterize the nature of the hemorrhage that accompanies liver xenotransplantation. Canine livers were transplanted into porcine recipients, and lethal hemorrhage was encountered. Analysis of recipient blood showed that factors V, IX, and X were present in adequate levels until after the hemorrhage appeared, suggesting that coagulation factor loss was the result and not the cause of hemorrhage. Platelet counts decreased dramatically in recipients within minutes of graft reperfusion. There also was no evidence of clotting activity in the blood of recipients of liver xenografts within minutes of graft reperfusion. This loss of clotting activity was specific to liver xenografts, was not seen in renal xenografts with or without venovenous bypass, and also was absent in pig-to-pig liver allografts. In brief, the hemorrhage that accompanies liver xenotransplantation occurs because of a decrease in the number and function of circulating platelets in the recipient.
Problems raised by major hepatobiliary surgery affect the total economy of the human body. The liver is implicated in all body metabolism processes and possible problems during partial or total hepatectomy can only be solved by a knowledge of liver physiology. The liver plays a major role in the metabolism of products of digestion, whether these are carbohydrates or amino acids arriving in the portal blood. The most important activity of the liver is the preservation of a constant level of glucose by ensuring a fixed and predictable concentration to extrahepatic tissues. It ensures a very precise control of plasma and tissue flow of amino acids and thus protein synthesis and neoglycogenesis. Synthesis and degradation of non-esterified fatty acids, ketogenesis, cholesterol synthesis and triglyceride production result from the action of the liver on lipid metabolism. Free cholesterol is the precursor of bile acids and steroid hormones, but esterified cholesterol is not synthetized in the liver. Apart from its role in bilirubin metabolism, it has a key role to play in correct functioning of most endocrine systems: many are catabolized in the liver. But one of the most interesting properties of the hepatic tissue, as far as the surgeon is concerned, is liver regeneration, which combines hypertrophy with hyperplasia. This is dependent on age, hepatotrophic factors of portal blood, and extraportal factors. A study of hepatic metabolic processes allows assessment of the consequences of partial hepatectomy. Postoperative hypoglycemia, in the absence of a continuous infusion of glucose, is easily explained by the weakness of hepatic reserves in glycogen. Albumin levels fall during the first 7-10 days after liver resection, but this hypo-albuminemia is often marked by the need to infuse large quantities of frozen fresh plasma to try to avoid lesions of the other specific proteins, which are coagulation factors. Lipid metabolism disorders are of little clinical consequence. Hepatic resection is being alarming when it involves 80 to 90% of the hepatic mass and menaces the life of the patient. The existence of a previous liver alteration worsens the consequences of major hepatobiliary surgery. Indications for hepatic resection must be weighed carefully in patients with cirrhosis, liver regeneration being totally absent after resection. Metabolic consequences of total hepatectomy followed by transplantation are identical in kind to those of partial hepatectomy but are increased in frequency and start during operation. Postoperative surveillance must be strict to avoid marked variations in glycemia with the risk of hypoglycemia, and variations in kaliemia.(ABSTRACT TRUNCATED AT 400 WORDS)
Seven members of one family over three generations were found to have a characteristic reduction to about 0.5 of the ratio between factor II clotting activity and factor II concentration, which was not seen when measuring prothrombin after activation with staphylocoagulase. In addition to the "normal" prothrombin, two abnormal prothrombins, with higher molecular weights and lower isoelectric points, were found by SDS-polyacrylamide gel electrophoresis. This is an autosomal hereditary dysprothrombinemia, the affected persons being heterozygotes. Five of the seven persons had a slightly increased bleeding tendency which manifested itself especially in more marked or prolonged posttraumatic and postoperative bleedings.
Resistance to activated protein C (APC) is among the coagulation disorders that have been implicated in retinal vein occlusion. However, since retinal vascular occlusions may be due to a combination of several mechanisms, the question of whether thrombophilic anomalies are pathogenic for this disorder remains controversial. In the current study, we investigated the prevalence of APC resistance in patients with retinal vein occlusion with reference to age and various cardiovascular risk factors. A cohort of 142 consecutive patients with retinal vein occlusion and a control group of 128 subjects matched for age, sex and several risk factors were screened for resistance to APC. Both cohorts were divided into two subgroups, according to the patient's age (< or =45 or >45 years) at the time of the retinal vein occlusion or a previous thromboembolic event. The proportion of individuals with resistance to APC was higher in the patient group (13 of 142; 9.1%) when compared to controls (6 of 128; 4.7%). Moreover, patient age < or =45 years by the time of the retinal vein occlusion or a previous thromboembolic event was significantly associated with a high prevalence of APC resistance (17%). By contrast, resistance to APC was present in 5 of 95 cases (5.3%) in the patient group >45 years and in 4 of 83 (4.8%) young controls. Our results indicate that APC resistance is highly prevalent in patients with retinal vein occlusion at age < or =45 years and/or with a history of thrombosis at this age. By contrast, the prevalence of APC resistance in patients who suffered a retinal vein occlusion when they were older than 45 years and had no history of thromboembolism appears to be similar to that seen in healthy control subjects or in the normal population. Selective screening may be helpful in identifying retinal vein occlusion patients with thrombophilic defects.
This article explores two of the components of the system involving the physiologic regulation of the coagulation cascade: anti-thrombin III and protein C. Pertinent molecular biology is reviewed, and the clinical conditions associated with changes in the proteins are discussed.
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In a family with a known antithrombin III abnormality (AT III Trento) an associated von Willebrand defect (Type I) was found. The two defects seem to segregate independently. In fact four types of individuals were present, namely: subjects with isolated AT III abnormality, subjects with isolated von Willebrand defect, patients with double defect and normal subjects. Only one of the two patients with isolated AT III abnormality showed a thrombotic tendency. None of the patients with double defect showed thrombotic disease, indicating a possible protective action of the von Willebrand defect against thrombotic manifestations. Patients with isolated von Willebrand defect showed neither thrombotic nor bleeding manifestations. The study emphasizes the need for a careful evaluation of the hemostatic balance of patients with AT III abnormalities before concluding that they are symptomatic or asymptomatic.
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