RESUMO
This unusual report shows the association between thoracic aortic mural thrombus formation and the hypercoagulable state without concomitant disseminated intravascular coagulation. The patient's hypercoagulability was reflected by laboratory results that included elevated Factor VIII and fibrinogen levels, along with a decreased level of antithrombin III. The underlying cause was probably acute peritonitis, a condition associated with coagulopathy.
RESUMO
Severe and even fatal hemorrhage may be caused by bleeding through the interstices of a fabric graft. Improved fabrication of grafts with appropriate porosity for the conditions encountered has provided better hemostasis. Yet in some situations, bleeding through the fabric still presents a problem. A method of preclotting with autologous platelet rich plasma (PRP) and autoclaving is described. Gross and microscopic studies along with clinical applications confirm the effectiveness of the technique.
RESUMO
Among a series of 109 patients who underwent aortocoronary artery bypass reoperation and received a total of 168 grafts, atherosclerosis was found in 29 saphenous vein grafts. Specimens were obtained at reoperation in 25 patients and at postmortem examination in four. Plaques were found from 3 months to 6 years after operation. The plaques often were combined with old or recent mural thrombi, intimal fibroses, or thickened intima associated with intramural hematomas. Clinical findings did not correlate with risk factors such as hypercholesterolemia, hypertension, or diabetes mellitus. In a well-functioning graft with adequate flow, cellular proliferation generally reflects an adjustment of the venous wall to a higher pressure. Such a vessel retains elastic properties of pulsating structures. In the specimens studied, intimal fibrosis associated with plaques was always poorly cellular, causing the grafts to become rigid. This resulted in irregular flow and, in some patients, dissection. The possible pathogenesis of atheromatosis in vein grafts may include the usual mechanisms of atherogenesis and atheromatous transformation of thrombi. It appears that hemodynamically significant stenosis of vein grafts caused by atherosclerosis is an infrequent complication.
RESUMO
Following each of 21 clinical trials with the partial artificial heart or abdominal left ventricular assist device (ALVAD), we have examined the blood-interfacing human pseudoneointimal (PNI) linings formed on the fibril-flocked pumping surface by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The salient results of these ultrastructural analyses can be summarized: (1) early PNI accretion kinetics (< 24 hrs) involve plasma protein adsorption, entrapment of erythrocytes, platelets, lymphocytes, numerous neutrophils and macrophages, and the deposition of fibrin within fibril flock interstices (TEM); (2) the surface (< 24 hrs) consists of interconnected fibrin strands (SEM); (3) later PNI accretion kinetics (1-6 days) involve the formation of alternating cellular and fibrin layers (TEM); (4) the surface (1-6 days) consists of cellular aggregates (inter-membrane distances of 340 A) simulating an endothelial interface (SEM, TEM). Based on these analyses, a plausible sequence of events for human PNI accretion kinetics can be advanced, i.e., 0-24 hrs: (a) maximal foreign body response of blood in contact with Dacron fibrils, (b) cellular lysis and fibrin compaction; 1-6 days: (c) accretion and lysis of cellular aggregates (neutrophils, macrophages) 3-4micro thick, (d) accretion of linear fibrin aggregates, 8-10micro thick, and (e) cyclic replication (up to six) of phases c and d.
RESUMO
Biochemical, hematologic and coagulation values have been determined in normal Hereford calves of both sexes, two to six months of age. These data generally agree with those of others and indicate a similarity in calves irrespective of their age, sex or breed. Prothrombin times are markedly longer in the calf than in man. This has resulted in alterations of anticoagulation regimens after implantation of mechanical circulatory support systems.
