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At least 19 recordsLinked to original sources
PubMed1979

Infection of glutaraldehyde-preserved porcine valve heterografts.

Gross, histologic and ultrastructural changes associated with bacterial infection are described in four porcine valve heterografts that had been in place in patients for 6 days to 28 months. In one patient, culture of the aortic tissue tag included in the heterograft container grew Mycobacterium chelonei; however, examination of the heterograft, recovered at necropsy 6 days after implantation, revealed small colonies of bacteria that differed morphologically from mycobacteria. A second heterograft was the site of staphylococcal infection associated with extensive destruction of collagen in the leaflets. Similar destruction was observed in a third heterograft, which was found to have organisms on ultrastructural study even though bacterial cultures of the valve were negative. The fourth heterograft, from a patient who died of coronary embolism secondary to dislodgment of vegetative material, contained structures resembling lysed bacteria. Observations in these 4 patients and review of published reports of infection involving 43 other patients with porcine valve heterografts indicates that infection in these valves: (1) develops in the fibrin layer that covers the cusps, (2) can involve the collagen in the leaflets, and (3) is uncommonly (three patients) associated with valve ring abscesses.

Adult↗
PubMed1978

Oral scleral heterografts. A pilot study.

This study showed that scleral heterografts in the oral cavity work. Such grafts demonstrate the following characteristics: (1) attach firmly to submucosal, periosteal, and bony tissues; (2) remain firm and fibrotic in nature, indicating the possibility of a stressbearing tissue; (3) show little or no scarring or contracture; (4) show minimal, or no- host antigenic response based on clinical acceptance; (5) appear to become vascularized and cellular, blending with adjacent collagen. As projected by this study, scleral heterografts might well be used to obliterate bony undercuts and perhaps to obtund cystic cavities and other major bony defects. Further studies of layering of the sclera are essential before any definitive result can be determined in large bony defects. In those areas in which no bone regeneration would be feasible, such as in the mylohyoid region of the mandible, this application does present a possibility for removing undercuts as opposed to removing overlying bone. The tenacity of adherence to submucosal tissues, periosteum, and bone makes scleral heterografting even more intriguing in the possible obliteration of oroantral fistulas. We might theorize that the sclera would not only attach to the buccal and palatal flaps but also show a rather firm and tenacious adherence to the bony walls of the antral defect. The availability of human bank sclera for use as presently made by periodontists and as pioneered by Klingsberg is somewhat limited. From our study, an extrapolation would indicate that, because of the comparably low and antigenicity of bovine sclera and human sclera, an investigation in this area should be completed in order to determine whether scleral heterografts can replace scleral homografts in human periodontal surgery. Sclera is easily preserved in anhydrous glycerine (as preserved by King and associates19) and can certainly be stored in banks. In our opinion, the final application of scleral heterografts, human or bovine, the role of antigenicity, and the ability of osteoblasts to invade either a single piece or layers of sclera warrant further study.

Alveolar Process↗
PubMed1979

Calcific stenosis of the porcine heterograft.

We have encountered two cases of late calcification of the porcine heterograft. A patient in chronic renal failure died of sepsis and endocarditis fifteen months after replacement of the mitral and tricuspid valves. At postmortem examination, both heterograft valves exhibited severe calcification and thrombosis. A second patient with rheumatic heart disease and sickle cell disease underwent mitral valve replacement for severe regurgitation. Thirty months later, cardiac catheterization revealed prosthetic valve stenosis. The valve was replaced successfully, and the excised heterograft exhibited severe calcification with restriction of leaflet motion. Although calcification of the porcine heterograft is known to occur in patients with infection or disorders of calcium metabolism, dysfunction of the heterograft is rare in our experience.

Adolescent↗
PubMed1976

Patch aortoplasty for insertion of the porcine heterograft.

The porcine heterograft has been shown to be a very satisfactory replacement for the diseased aortic valve. In certain cases, the advantage of a low thromboembolism rate without anticoagulation must be weighed against the suboptimal orifice size noted in the smallest heterografts. In using the largest replacement possible, the surgeon may encounter difficulty with closure of the aortotomy. Patch aortoplasty, as used in the 4 cases reported here, allows implantation of a larger heterograft. The technique is simple and adds little time to the operation. In selected cases, enlargement of the aortic root should result in better long-term hemodynamic performance.

Adult↗
PubMed1978

Structural changes in glutaraldehyde-treated porcine heterografts used as substitute cardiac valves. Transmission and scanning electron microscopic observations in 12 patients.

Scanning and transmission electron microscopic studies were made of (1) 12 glutaraldehyde-treated porcine valvular heterografts that had been implanted in patients for 2 days to 76 months; (2) 3 unimplanted commercially processed porcine aortic valves; and (3) 1 unprocessed porcine aortic valve. Comparison of unprocessed porcine valves and unimplanted commercially processed valves showed loss of endothelium and acid mucopolysaccharides during preimplantation processing. Short-term (less than 2 months) changes after implantation consisted of insudation of plasma proteins, penetration of erythrocytes into surface crevices, formation of a thin surface layer of fibrin, and deposition of macrophages, giant cells and a few platelets. Longer-term (more than 2 months) changes were proportional to the time interval after implantation and consisted of progressive disruption of collagen, erosion of the valve surfaces, formation of aggregates of platelets and accumulation of lipid. The surfaces of the leaflets did not become covered with endothelium or with a fibrous sheath. Calcific deposits were found in one valve and bacterial organisms in another. Thus, progressive breakdown of collagen appears to be a critical factor in determining the long-term durability of glutaraldehyde-treated porcine valvular heterografts.

Adult↗
PubMed1978

Structural alterations of the porcine heterograft after various durations of implantation.

Morphologic changes in six glutaraldehyde-fixed porcine heterografts recovered from five patients were studied with light and scanning electron microscopy. Light microscopy showed minimal changes in the valves recovered after 2 months of implantation. Fibrin deposits, red blood cell trapping, disruption of the valve matrix and interstitial edema were noted in heterografts 2 months and 2 years after implantation. In valves examined with scanning electron microscopy, 6 hours after implantation the surface changes varied from normal to patchy disruptions. Two months after inplantation, subendothelial fibers were conspicuous and the geometry of endothelial cells was changed. In valves examined after 6 months in place, many nuclei were burst and fibrin strands were seen over the surfaces. Bacterial infection was observed in two cases. The endothelial cells in the valve implanted for 2 years were completely obscured and some areas were densely covered with fibrillar material where blood cells were trapped in the mesh.

Adult↗
PubMed1977

Successful renal vein reconstruction with bovine arterial heterografts.

Extensive damage to a short right renal vein complicated transplant surgery in two patients. The use of a segment of modified bovine arterial heterograft permitted successful transplantation in both cases. These results are in contrast to the reported inability of bovine arterial heterografts to remain patent elsewhere in the systemic venous system.

Adult↗
PubMed1979

Aggressive approach to late thrombosis of bovine heterografts.

Between January, 1977 and December, 1978, 26 patients presented with delayed thrombosis of bovine heterografts inserted for chronic hemodialysis. Time of presentation ranged from 2-29 months (mean 8.8 months) after insertion. At the time of presentation eight patients were not considered candidates for thrombectomy due to associated infection or physician preference. The remaining eighteen patients underwent thrombectomy, 13 of whom required concomitant revision of the graft (patch angioplasty at the venous anastomosis (6), dilatation (1), resection of intimal hyperplasia (2), resection of stenotic segment with interposition graft (2), resection of false aneurysm (1) and patch graft to mid graft stenosis (1)). Six grafts failed from eight days to seven months after thrombectomy and could not be salvaged. Two grafts functioned until death at three and four months after thrombectomy and the remaining ten grafts remain patent from 4-24 months (mean 13.1 months) after thrombectomy. Critical to success of thrombectomy is an incision over the venous limb with calibration of the venous anastomosis and patch angioplasty when indicated. At completion of thrombectomy arteriograms are mandatory to defect residual thrombosis, defects in the graft and adequacy of venous runoff. This standardized approach has resulted in a significant prolongation of bovine heterograft survival.

Animals↗
PubMed1979

Unusual complication of the Hancock porcine heterograft: strut compression in the aortic root.

A 65-year-old man underwent aortic valve replacement and triple coronary artery bypass grafting which were followed by gradual late postoperative thrombosis of his 25 mm. Hancock porcine aortic heterograft. At reoperation, the valve struts were noted to be angled centrally into the aortic lumen and dense thrombus completely filled all three sinuses. After valve removal and extensive debridement of the aortic anulus, including relaxing incisions, a diameter of only 23 mm. was obtained. A 23 mm. Björk-Shiley aortic prosthesis was inserted and the patient's recovery was uneventful. This previously unreported complication resulted from the insertion of a too-large Hancock porcine heterograft into a relatively small aortic root, resulting in circumferential strut compression, impedance of central flow, and subsequent valve thrombosis.

Aged↗
PubMed1977

Hemodynamic assessment of the glutaraldehyde-preserved porcine heterograft in the aortic and mitral positions.

Although glutaraldehyde-preserved porcine heterograft (PH) valves may have a lowered incidence of thromboembolism compared to mechanical valves, data concerning postoperative function in PH valves are incomplete. Accordingly, 26 patients receiving PH in the aortic (AO) or mitral position (MIT) were studied at cardiac postoperative catheterization (mean 19 weeks). The 12 AO patients had an average peak systolic gradient of 19 mm Hg (range 3-52 mm Hg); mean valve area (VA) 1.33 cm2 (0.75-2.5; two patients had postoperative aortic insufficiency. The 14 MIT patients had a mean gradient of 7.9 mm Hg (0-13.1); VA 1.84 cm2 (0.70-3.2; postoperative mitral regurgitation occurred in two patients. AO stent diameter (SD) related to VA, r = 0.85; and peak gradient, r = -0.75. However, MIT SD did not relate to VA or peak gradient. At the 14-month follow-up examination 9 of 11 AO and 7 of 11 MIT patients improved by at least one functional class. Thus, with the advantage of reduced thromboembolism and generally satisfactory valve hemodynamics, further clinical trial of glutaraldehyde-preserved porcine heterografts is justified.

Adolescent↗
PubMed1979

Platelet aggregation inhibition in human umbilical vein grafts and negatively charged bovine heterografts.

Glutaraldehye-tanned human umbilical vein grafts (4 mm) and negatively charged bovine heterografts (4 mm) were placed as bypasses in the femoral arteries of 20 dogs randomized into 10 treated with aspirin and dipyridamole and 10 were not treated. Autogenous vein grafts were placed as controls. Platelet aggregation inhibition by aspirin and dipyridamole significantly improved the patency of human umbilical vein grafts from 10% to 60%. It had no effect on patencies of autogenous veins (100%) or on negatively charged bovine heterografts (0% patency). Inherent graft properties continue to play an important and sometimes overriding role in long-term graft patency in small vessel bypasses. Neointimal fibrous hyperplasia at both proximal and distal anastomoses again was shown to be intimately associated with late graft occlusions.

Animals↗
PubMed1979

Late failure of porcine valve heterografts in children.

Heterograft porcine valves have gained wide acceptance in replacement of diseased cardiac valves, and their clinical performance in adults has been very satisfactory over follow-up periods of up to 8 years. Valve replacement in children is relatively infrequent and experience with porcine xenografts is necessarily small. Our combined experience at three university hospitals has been with 25 children, 17 months to 16 years of age, who have been followed for 10 to 54 months (mean follow-up 33 months). Porcine valves were used to replace the aortic valve in nine, the mitral valve in seven, both valves in two, the tricuspid valve in two, and the pulmonary valve in five patients. Severe bioprosthetic valve dysfunction has occurred in five (20%) of these patients so far and necessitated replacement because of severe stenosis in mitral (two) or aortic (three) valve prostheses at 18 to 45 months after implantation; one postoperative death occurred among the five reoperations. Pathological examination showed extensive fragmentation of collagen with focal heavy calcification and degeneration. In addition we have encountered deterioration and calcification of two porcine valves in 23 valved conduits followed for 12 to 70 months (mean 43 months), requiring removal and replacement of the valves 65 and 67 months after implantation. This experience indicates a disquietingly high incidence of relatively early failure of porcine xenograft valves in children. This is significantly higher than the failure rate observed in adult patients. The failure rate is not consistently related to the small size of an implanted valve which becomes relatively narrow with the growth of the patient, leading to excessive turbulence and trauma to the prosthesis. Other factors, including increased turnover of calcium and accelerated rejection in growing children, may contribute to these failures and should be examined in order to improve long-term results. A satisfactory performance would make heterografts the ideal valvular prosthesis in children, since anticoagulation is avoided.

Adolescent↗
PubMed1977

Acute hemodynamic alterations after aortic valve replacement with the glutaraldehyde-treated porcine heterograft prosthesis.

Twenty-two patients underwent aortic valve replacement for acquired valvular heart disease with the porcine heterograft prosthesis. In the immediate postoperative period, a transient decrease in the cardiac index (CI) (preoperative 3.0 +/- 0.14 to 2.45 +/- 0.16 L. per minute per square meter, p less than 0.05) and an increase in the systemic vascular resistance (SVR) (preoperative 1,078 +/- 62 to 1,287 +/- 103) dynes/sec./cm.-5, p greater 0.05) were seen; these values returned to preoperative levels by the first postoperative day. After valve replacement, an elevation in the heart rate (HR) (preoperative 75 +/- 2 to 87 +/- 4 beats per minute, p less than 0.05) and a reduction in the stroke volume (SV) and stroke work index (SWI) (preoperative 35 +/- 2 to 26 +/- 2 Gm.-M. per square meter, p less than 0.05) occurred which persisted throughout the study. The endocardial viability ration (EVR) increased after valve replacement. These findings suggest that, following aortic valve replacement, (1) an increase HR is the mechanism utilized to maintain cardiac output, (2) subendocardial perfusion is enhanced as indicated by an increase in the EVR, and (3) the hemodynamic alterations following insertion of the porcine heterograft prosthesis are not different from those observed when other valves are placed in similar patient populations.

Adult↗
PubMedDate not supplied

Experimental preparation of deantigenized vascular heterografts and study of tolerance after transplantation.

A new technique in preparing a heterograft is presented. Deantigenized calf carotid arteries are obtained by papain digestion and formol tanning. The biochemical determinations show a pronounced reduction in total protein content after papain digestion. The formol tanning gives a good rigidity and elasticity in adapting to different blood volumes without aneurysmal dilatation. Eight dogs were grafted : two died after surgery, two were killed after 35 days and two others 60 days after transplantation, one died after 8 months and one is alive 30 months after transplantation. The good in vivo tolerability has been appreciated. There have been no haemodynamic troubles and no cell changes of rejection. An insignificant quantity of immunoglobulins G has been found in the sera of the animals with heterografts. These data draw attention on the possibility of the use, in clinical practice, of the deantigenized calf arteries.

Animals↗
PubMed1978

Hemolytic anemia associated with heterograft replacement of the mitral valve.

The first case of overt hemolytic anemia following mitral valve replacement with a porcine heterograft is reported. Cardiac catheterization failed to reveal a paravalvular leak or valvular incompetence to account for the hemolysis. Red cell traumatization by the Dacron-covered Stellite ring and stent is suggested as the cause of hemolysis with the porcine heterograft.

Anemia, Hemolytic↗
PubMed1978

Severe and early stenosis of porcine heterograft mitral valve.

A patient who had aortic and mitral valves replaced by Carpentier porcine heterografts for bacterial endocarditis developed severe heart failure 18 days after operation. A second emergency operation revealed that the mitral prosthesis had become severely stenosed and calcified. A loud Graham Steell murmur had developed during the 12 hours before reoperation but no distinct murmurs of mitral stenosis had been detected.

Adult↗
PubMed1977

Preliminary studies with L-asparaginase bound to implantable bovine collagen heterografts: a potential long-term, sustained dosage, antitumor enzyme therapy system.

In this study, L-Asparaginase has been bound to collagen heterografts derived from carotid bovine arteries. The immobilization procedure utilizes both non-covalent and covalent interactions to fix the enzyme. Binding of the enzyme to the graft material was shown to the pH dependent, with optimum binding occurring at pH 6.0 and pH 8.5. Amidohydrolysis by the bound enzyme exhibited zero-order kinetic behavior at substrate saturating conditions. Total apparent asparaginase activity expressed by the grafts as a function of the number of repeated in vitro assay trials demonstrated that over a span of 3 months of intermittent storage and use, the enzyme-grafts retained as much as 62% of their initial activities. Implantation of 4 asparaginase-collagen grafts in various locations of the thoracic and abdominal aorta resulting in prolonged reductions of plasma asparagine levels in 3 of the 4 implants. Presence of plasma asparaginase was checked in one of the four implants and determined to be less than 2 X 10(-4) I.U./ml. Removal of grafts from 3 of the 4 animal subjects showed reductions in the apparent asparaginase activity expressed by the grafts of 7 to 70 percent after in vivo contact times which varied from 6 to 15 days.

Animals↗