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Query: UMLS:C0162871 (abdominal aortic aneurysm)
 8,664 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vascular grafts with primary zero porosity are desirable in surgery for aortic aneurysms with intraoperative partial or total systemic heparinization of the patient. The present study describes the clinical application and results of a new knitted Dacron double-velour prosthesis (primary porosity: 1,400 cc/min/cm2), coated with cross-linked bovine collagen; the resulting porosity for implantation is O cc/min/cm2. Such grafts were implanted in 111 patients between 12/83 and 11/84: for replacement of the infrarenal aorta in 74 aneurysms, for replacement of the thoraco-abdominal aorta in 4 instances, and for replacement of 13 aneurysms of the descending aorta. In 20 patients with arterial occlusive disease, the prosthesis was employed as bifurcation graft. In 43 cases (38%) the underlying disease was a ruptured (26) or symptomatic aortic aneurysm requiring emergency operation. There was no leakage from any of the implanted grafts regardless of whether partial (100 units/kg BW) or total (300 units/kg BW) systemic heparinization was administered. The overall mortality rate was 11.7% (13/111). For cases of ruptured abdominal aortic aneurysm the mortality rate was 22.7% (5/22). There was no graft-related complication either in the early postoperative course or during the follow-up period (1 to 10 months, mean: 6.2 months). It is concluded that this new type of graft combines the advantages of knitted Dacron prostheses in respect to healing and incorporation with primary zero porosity, and is therefore the graft of choice in surgery for ruptured aortic aneurysm.
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PMID:Clinical experience with a new collagen-coated Dacron double-velour prosthesis. 242 51

We report and analyze two cases of Ehlers-Danlos syndrome (EDS) type 4. The first manifestation of the disease was a spontaneous perforation of the colon in a 47-year-old man; he was successfully reoperated on five years later for the rupture of an abdominal aortic aneurysm. Abdominal pain demonstrated the syndrome in a 33-year-old woman in whom multiple abdominal aneurysms were found. A ligation of the anterior tibial artery for spontaneous rupture was performed five years later. Light and electron microscopic studies of the skin disclosed similar alterations in both cases. The diameter of the collagen fiber bundles was reduced and the diameter of collagen fibrils was increased. It appears that EDS type 4 might be less characteristic than has been previously described. Classification of the different types of EDS according to electron microscopy is not possible.
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PMID:Changing patterns in the vascular form of Ehlers-Danlos syndrome. 374 Nov 1

Bone-inducing materials have been investigated for the purpose of augmenting bone formation in implants made of porous fiber titanium. The bone-inducing materials used were: (1) Bone from the iliac crest of inbred rats (isografts), (2) Antigen-extracted, autolyzed, demineralized bone from outbred rats (AAA bone a.m. Urist), and (3) AAA bone combined with bone marrow from inbred rats. Tubes of fiber titanium were packed with bone-inducing materials and implanted in the back musculature of inbred rats. Bone formation was assessed by labelling with 3H-proline (collagen synthesis) and 47Ca (mineral deposit) and by content of calcium of the harvested implants. Isografts and AAA bone with marrow yielded a substantial amount of new bone. Without the marrow, AAA bone yielded very small amounts of new bone.
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PMID:Bone formation enhanced by induction. Bone growth in titanium implants in rats. 388 73

Between 1975 and 1985 502 patients (52 female, 450 male, aged 29 to 88 years, mean 66 years) were operated for abdominal aortic aneurysm (AAA). In 261 electively operated patients hospital mortality was 4.9% (group A). In 79 patients with impending rupture the rate was 12.2% (group B) and of 125 patients with a ruptured AAA 46.6% died (group C). Of 42 patients with thoraco-abdominal aneurysm (group D) 11 had a rupture. Mortality was 66%. These figures could be improved. Between November 1983 to the end of 1984 in group A lethality was 4.1% (2/49), in group B 6.25% (1/16), in group C 33% (8/24). Of the last 4 patients of group D operated electively 1 died. Reasons for this improvement were: 1. improved anesthesiological management, 2. use of graft-inclusion-technique, 3. implantation of straight tube grafts instead of bifurcated prostheses, 4. use of collagen-coated Dacron prostheses.
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PMID:[Surgery of abdominal aortic aneurysm--results in 502 patients]. 405 71

A spontaneously aneurysm-prone mouse has a mutation on the X chromosome, which results in an abnormality of copper metabolism. A deficiency of the copper metalloenzyme, lysyl oxidase, results in a deficiency of lysyl-derived cross-linkages in collagen and elastin. Homology of the X chromosome suggests that this model may be relevant to the human abdominal aortic aneurysm (AAA). The present studies on skin from eight AAA patients suggest that copper deficiency occurs in humans, by comparison to skin of paired control subjects with atherosclerotic occlusive disease of the aorta. The lysyl-derived cross-linkage pyridinoline (or some compound with similar ion exchange elution characteristics) is also deficient in patients with AAA; while there is an excess of one of the cross-linkage precursors, hydroxylysine. In addition, the fluorescent properties of hydrolysates of skin from the patients with AAA differ from those of the controls, suggesting that simple biochemical markers might be defined on the basis of these differences in the future. These experiments support the hypothesis that the mouse model is relevant to the disease as it occurs in humans.
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PMID:Deficiencies of copper and a compound with ion-exchange characteristics of pyridinoline in skin from patients with abdominal aortic aneurysms. 687 35

An 82-year-old man with a one-year history of spontaneous ecchymoses and posttraumatic bleeding was found on physical examination to have a pulsatile abdominal mass. Ultrasonography revealed a large abdominal aortic aneurysm with a freely moving 1.5--2-cm intraluminal thrombus. Laboratory data disclosed intravascular hemolysis, disseminated intravascular coagulation, and a prolonged bleeding time. Further investigation of platelet function demonstrated decreased glass bead retention (0-15%), and reduced or delayed aggregation responses to adenosine diphosphate, epinephrine, and collagen. Studies of platelet factor 3 availability, antiplatelet antibodies, and aggregation response to ristocetin were normal. Transfusion of ten units of normal platelets failed to shorten the patient's bleeding time, despite a marked rise in platelet count. Glass bead retention studies on normal and patient blood were not altered by mixture with patient and normal platelet-poor plasma, respectively. Platelet dysfunction in the presence of arterial aneurysm does not appear to have been reported previously.
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PMID:Platelet dysfunction associated with abdominal aortic aneurysm. 744 78

The risk of rupture of an abdominal aortic aneurysm increases with aortic diameter. To obtain insight into the pathological processes associated with the vascular remodeling that accompanies aortic dilatation, we compared the histological features and the activity of matrix metalloproteinases (MMPs) in biopsies from 21 small (4.0 to 5.5 cm in diameter) and 45 larger abdominal aortic aneurysms. The histological feature most clearly associated with enlarging aneurysm diameter was a higher density of inflammatory cells in the adventitia, P = .018. This inflammation was nonspecific, principally macrophages and B lymphocytes. Fibrosis of the adventitia provided compensatory thickening of the aortic wall as the aneurysm diameter increased. A combination of zymography and immunoblotting identified gelatinase A (MMP-2) as the principal metallogelatinase in small aneurysms, whereas zymography indicated an increasing activity of gelatinase B (MMP-9) in large aneurysms. Homogenates prepared from both small and large aneurysms had similar total activity against gelatin or type IV collagen. However, the concentration of gelatinase A, determined by immunoassay, was highest for small aneurysms: median concentrations, 385, 244, and 166 ng/mg protein for small aneurysms, large aneurysms, and atherosclerotic aorta, respectively. Immunolocalization studies indicated that gelatinase A was concentrated along fibrous tissue of both the acellular media and the atherosclerotic plaque. The recruitment of inflammatory cells into the adventitia, with subsequent elaboration of metalloproteinases, including gelatinase B, may contribute to the rapid growth and rupture of larger aneurysms.
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PMID:Inflammation and matrix metalloproteinases in the enlarging abdominal aortic aneurysm. 762 8

We now know our past concepts of AAA pathogenesis to be oversimplified and inaccurate. In fact, the metabolic activity of the aneurysm wall is markedly increased in comparison with normal aorta. It has become clear that AAAs result not from passive dilatation, but from a complex remodeling process involving both the synthesis and degradation of matrix proteins. Our understanding of this process has been advanced by applying molecular biology techniques. Although elastin fragmentation and medial attenuation remain the most striking histological features of AAA tissue, experimental and clinical evidence suggests that the adventitia, which is predominantly collagen, is capable of maintaining the dimensional stability of the aorta in the absence of the medial elastin network. Thus, although factors that result in fragmentation and attenuation of elastin may be important in the etiology of AAA, factors regulating the balance of collagen synthesis and degradation likely determine the rate of AAA progression. The resident inflammatory cells in AAA undoubtedly play an important pathological role in aortic dilatation. Thus, understanding the interaction between aortic mesenchymal cells (smooth muscle cells and fibroblasts) and inflammatory cells (lymphocytes and macrophages) should allow for the identification of genetic factors that predispose to AAA. In addition to the possibility of early identification of patients at risk for AAA, new insights into AAA pathogenesis might allow for development of pharmacological strategies for inhibiting expansion of small AAA.
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PMID:Pathogenesis of aneurysms. 767 Jun 68

The pathogenesis of abdominal aortic aneurysm involves many factors acting over time. However, destruction of elastin in the aortic wall is a key event that shifts the load produced by blood pressure on to collagen. This is exacerbated in the presence of hypertension. Smoking and age are further important factors, as is the site; elastic lamellae are relatively less common in the abdominal aorta. Once the shielding effect of elastin is lost, further dilatation and rupture of the aorta depend on the physical properties of the collagen present.
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PMID:Pathogenesis of abdominal aortic aneurysm. 792 83

The decrease in elastin concentration in abdominal aortic aneurysm (AAA) has been ascribed to elastolysis. The discordant response of the elastin and collagen genes in AAA suggests a different explanation: dilution of elastin because of higher levels of synthesis of collagen and other matrix proteins. The purpose of this study was to determine circumferential content of elastin, collagen, and total protein in aneurysmal (AAA), atherosclerotic, and normal (NL) infrarenal aorta. Standard serial extraction techniques of complete 1-cm rings of midinfrarenal aortic tissue were used to remove soluble protein, calcium, and lipids. Hydroxyproline (collagen), desmosine/isodesmosine (elastin), and total amino acid (total protein) content were determined by amino acid analysis. Means values (+/- SEM) were compared by ANOVA. Circumferential content of desmosine/isodesmosine was increased 2.5-fold in AAA compared to NL (P < 0.05). Collagen and total protein were increased 5.7- and 4.7-fold, respectively (P < 0.05). There was a high degree of correlation between circumference and collagen content (r = 0.89). These data demonstrate that significant synthesis of matrix proteins accompanies aortic dilatation. While both elastin and collagen are increased, there is a much greater increase in circumferential collagen content than elastin content. These data do not preclude proteolysis as a factor in AAA but suggest that the decrease in elastin concentration results from dilution of elastin by a greater increase in the synthesis of other matrix proteins and that synthesis is an important factor in AAA formation.
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PMID:Elastin is increased in abdominal aortic aneurysms. 793 21


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