fibrin and Aortic-Aneurysm

Customized aortic repair (CAR) is a new concept for endovascular aortic aneurysm repair in which a non-polymerised elastomer is injected to fill the aneurysm sac around a balloon catheter. Amongst other variables, the thrombogenicity of the elastomer should be tested, before further clinical experiments can take place. The aim of this human ex vivo study was to measure the thrombogenicity of the elastomer and to compare it to expanded polytetrafluoroethylene (ePTFE).. In a validated ex vivo model, non-anticoagulated blood was drawn from the antecubital veins of 10 healthy donors with a 19-gauge needle. It was drawn through elastomer tubes and through ePTFE Gore-Tex vascular grafts, both 60 cm long and with an inner diameter of 3 mm.. Fibrinopeptide A (FPA) and P-selectin expression was measured in blood samples, collected at the end of the grafts. After the experiments, the deposition of platelets and fibrin onto the grafts was visualised by scanning electron microscopy.. For these graft types, a progressive increase in FPA production was observed in time. No significant difference was observed between the elastomer and ePTFE grafts (p > 0.05). No increase in P-selectin expression, and thereby no platelet activation, was observed in the perfusate of either grafts (p > 0.05). By scanning electron microscopy, numerous platelet aggregates were observed on the ePTFE grafts, whereas just a few adhered platelets and no aggregates were observed in the elastomer grafts.. The elastomer in its current formulation has a low thrombogenicity, comparable to ePTFE, making it an ideal substance for endovascular aneurysm sac filling. Further research should clarify the feasibility of CAR in vivo.

Topics: Adult; Aortic Aneurysm; Blood Vessel Prosthesis; Blood Vessel Prosthesis Implantation; Dimethylpolysiloxanes; Endovascular Procedures; Fibrin; Fibrinopeptide A; Humans; Injections; Male; Microscopy, Electron, Scanning; P-Selectin; Platelet Adhesiveness; Polytetrafluoroethylene; Prosthesis Design; Silicone Elastomers; Thrombosis; Time Factors; Young Adult

To minimize intraoperative blood loss a watertight knitted Dacron aortoiliac prosthesis has been developed by impregnation with bovine collagen. A potential disadvantage is that collagen may be associated with an increase in thrombus formation. We conducted a prospective randomized trial to study the systemic effects of collagen-impregnated prostheses and of aortoiliac operation as such on the coagulation mechanism during the first 10 days after operation. Forty-one patients randomly received either a collagen-impregnated (n = 20) or a nonimpregnated prosthesis (n = 21). Twelve patients who underwent cholecystectomies served as controls. Three markers of the coagulation mechanism were monitored: beta-thromboglobulin, fibrinopeptide A, and fibrin/fibrinogen degradation products. We found no significant differences in median beta-thromboglobulin, fibrinopeptide A, and fibrin/fibrinogen degradation product levels between patients in the collagen-impregnated prosthesis group and patients in the nonimpregnated prosthesis group. This indicates that collagen does not stimulate the coagulation cascade any more than conventional Dacron protheses do. In a comparison of patients who underwent aortoiliac reconstruction and patients who underwent cholecystectomies, the results indicated a significant increased platelet activation and fibrin metabolism in aortoiliac reconstruction group compared with the control group. Finally, we observed a significantly higher preoperative fibrin metabolism in patients with vascular disease than in control subjects. This difference is attributable to the high preoperative fibrin/fibrinogen degradation product values in patients with aortic aneurysms.

Topics: Adult; Aged; Aged, 80 and over; Aorta; Aortic Aneurysm; Arterial Occlusive Diseases; beta-Thromboglobulin; Blood Vessel Prosthesis; Collagen; Female; Femoral Artery; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinopeptide A; Graft Occlusion, Vascular; Humans; Iliac Artery; Male; Middle Aged; Platelet Activation; Polyethylene Terephthalates

Topics: Acute Disease; Animals; Aorta; Aortic Aneurysm; Aortic Dissection; Dogs; Fibrin; Tissue Adhesives

Topics: Adult; Aged; Animals; Aorta; Aorta, Abdominal; Aortic Aneurysm; Blood Vessel Prosthesis; Dogs; Female; Fibrin; Humans; Male; Middle Aged; Polyethylene Terephthalates; Thrombin

A prospective study of 76 preoperative patients with aortic aneurysms was undertaken to determine the true incidence of associated disseminated intravascular coagulation (DIC). Although 39% of the patients showed a notable elevation of the fibrin split products level, only three had thrombocytopenia and a clinical bleeding diathesis, as well. Thus, clinically overt DIC occurred preoperatively in only 4% of the patients. All three patients had extensive aneurysms that involved the thoracoabdominal aorta. Preoperative fibrinogen levels in this series tended to be high-normal or elevated and were not good indicators of underlying excessive fibrinolysis. Hemostatic abnormalities, such as ecchymoses and petechiae, may be the key to the clinical diagnosis of DIC in preoperative patients with aortic aneurysms.

Topics: Aged; Aorta, Abdominal; Aorta, Thoracic; Aortic Aneurysm; Blood Platelet Disorders; Disseminated Intravascular Coagulation; Female; Fibrin; Fibrinogen; Hemorrhagic Disorders; Humans; Prospective Studies

Vascular prostheses of different porosity (Cooley Very Soft; Miliknit Lo-Por; Microvel; Sparks Mandril) were pretreated with fibrin glue and the permeability was assessed both in vitro and in 12 dog experiments by descending aorta replacement under full systemic heparinization. It was found that all types of prostheses were completely sealed after the pretreatment. In 28 patients undergoing descending or abdominal aorta replacement under systemic heparinization high porosity knitted Dacron grafts were pretreated with the fibrin glue only. There was no blood loss across the prosthetic wall. It is concluded that graft-pretreatment with fibrin glue allows for combining full heparinization and the use of high porosity vascular grafts.

Topics: Animals; Aorta, Abdominal; Aorta, Thoracic; Aortic Aneurysm; Aprotinin; Blood Vessel Prosthesis; Dogs; Fibrin; Fibrinogen; Humans; Permeability; Prosthesis Design; Thrombin; Tissue Adhesives

The protein composition of cell-free thrombus contained in abdominal aneurysms of the aorta was investigated using PAGE and immunoreactivity after solubilization. 1. The dry weight was 18--29%, with minor differences between various locations. 2. 35--40% of the dry weight was extractable with NaCl/citrate and was identified as albumin (80%) and IgG (15%). Trace amounts of fibrinogen immunoreactive material were present. 3. The NaCl/citrate insoluble part was 80% hydrolyzable with plasmin. The predominant fragment was D-D dimer (from cross-linked fibrin). In addition, fragments Dand E were observed. Reduction of the NaCl/citrate insoluble part with 2-mercaptoethanol resulted in almost complete solubilization. PAGE analysis demonstrated alpha-polmers, gamma-gamma dimers and little free alpha-chains, indicating almost complete cross-linking of fibrin. Thus, the major protein were cross-linked fibrin, albumin and IgG.

Topics: Aortic Aneurysm; Blood Proteins; Cell-Free System; Fibrin; Humans; Immunoglobulin G; Serum Albumin

Intravascular clotting and fibrinolysis (C and F) are events which often accompany major surgical trauma. Their role in inducing cardiopulmonary failure is debated and prompted this study of 13 patients undergoing elective AAA. Following intubation, anesthesia and pressure breathing fibrinolytic activity (FA) in arterial blood exceeded that in mixed venous blood (p < 0.001) indicating pulmonary secretion of proteolytic activity. Fibrinogen, plasminogen and fibrin degradation products (FDPs) were normal. During surgery, fibrinogen and plasminogen fell (p < 0.001) while nonplasmin mediated FA and FDPs rose (p < .001). Despite heparinization (5000 U IV) aortic clamping (avg 56 min) led to evidence of C and F within the lungs. Arterial fibrinogen was 33.2 mg/ml lower than mixed venous blood (p < 0.01) and plasminogen was 0.47 Sherry units lower (p < 0.001). Soluble fibrin monomer appeared in arterial blood (p < 0.01). At the same time nonplasmin mediated FA was consumed within the lungs (p < 0.01) and FDPs were produced (44.6 microg/ml higher in arterial blood, p < 0.001). Similar changes were noted after aortic declamping. The transient 5.3 ml/cm H(2)0 fall in dynamic compliance was unrelated to C and F. Pulmonary vascular resistance and arterial pressure were unchanged. During wound closure intrapulmonary C and F ceased. Postoperatively (6 h), the physiologic shunt of 15.1% was similar to tbe preoperative value of 13.3%. All C and F factors returned to normal except FDPs which remained elevated. An average of 0.2 U blood was given prior to aortic clamping and 3.1 U during clamping. Neither the volume nor the type of blood (7 patients received washed RBCs) influenced pulmonary C and F. The results show that pressure breathing will alter pulmonary metabolism from clearance to secretion of fibrinolytic activity. Surgery leads to systemic C and F while intrapulmonary C and F is triggered by aortic clamping despite IV heparin. Delayed functional consequences of C and F are possible. Immediate postoperative effects are not apparent.

Topics: Aorta, Abdominal; Aortic Aneurysm; Disseminated Intravascular Coagulation; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Fibrinolysis; Hemodynamics; Humans; Intraoperative Period; Lung; Plasminogen; Pulmonary Circulation; Time Factors

A prospective study was performed on 32 consecutive patients undergoing elective operations on the abdominal aorta. Dacron prosthetic grafts were used to replace resected abdominal aortic aneurysms or to bypass aorta-iliac occlusive disease. Complete coagulation studies were performed preoperatively, immediately postoperatively and 24 hours postoperatively. Twenty to 30 per cent of the patients had significant postoperative alterations in prothrombin time, partial thromboplastin time and platelet count. Fibrin monomer, fibrin split products and plasminogen were abnormal in 40 to 80 per cent of the patients postoperatively. Results of preoperative studies showed no significant abnormalities. One of the 32 patients had mild clinical evidence of disseminated intravascular coagulation postoperatively, which was treated with 5 units of heparin per kilogram per hour. Results of the study indicate that aortic grafting procedures frequently produce intravascular coagulation, either local or disseminated. In most patients, this is offset by activation of the fibrinolytic system. However, clinically significant sequelae may result, requiring prompt recognition and treatment.

Topics: Aged; Aorta, Abdominal; Aortic Aneurysm; Aortic Diseases; Arterial Occlusive Diseases; Blood Cell Count; Blood Coagulation Tests; Blood Platelets; Blood Vessel Prosthesis; Disseminated Intravascular Coagulation; Female; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Humans; Male; Middle Aged; Postoperative Complications; Prospective Studies; Prothrombin Time; Thromboplastin

A consumption coagulopathy was demonstrated in each of four patients with either ruptured aneurysm of the aorta or a dissecting aortic aneurysm. The most prominent features of this disorder were (1) a prolonged prothrombine time due to a decrease of one or more clotting factors, and (2) formation of fibrin and fibrinogen degradation products. Recognition of this coagulation disorder could be a valuable diagnostic tool to differentiate a ruptured or dissecting aortic aneurysm from other conditions with a similar acute onset. The coagulation disorder could be due to liberation of coagulant material from the aortic wall into the circulation or to an accumulation of clotting factors at the site of the lesion, secondary to the local exposition of tissue factors from the torn arterial wall. The probability of the latter mechanism is suggested by the local increase of radioactivity after the injection of 125I-fibrinogen.

Topics: Aged; Aortic Aneurysm; Blood Coagulation Tests; Disseminated Intravascular Coagulation; Female; Fibrin; Fibrinogen; Humans; Male; Middle Aged; Rupture, Spontaneous

Topics: Aged; Aorta, Abdominal; Aortic Aneurysm; Autopsy; Blood Vessel Prosthesis; Fibrin; Fibrinogen; Fluorescent Antibody Technique; Humans; Immunoglobulin G; Kidney; Kidney Diseases; Kidney Glomerulus; Middle Aged; Polytetrafluoroethylene; Postoperative Complications; Rupture, Spontaneous

Topics: Adult; Aged; Aneurysm; Aortic Aneurysm; Arteriosclerosis; Blood Cell Count; Blood Coagulation; Blood Platelets; Buttocks; Cell Survival; Chromium Radioisotopes; Chronic Disease; Disseminated Intravascular Coagulation; Female; Fibrin; Fibrinogen; Hemangioma; Humans; Iodine Radioisotopes; Middle Aged; Purpura, Thrombocytopenic; Skin Neoplasms; Syndrome; Thrombosis