Mitral valve replacement with aortic heterografts in humans

Ionescu, Marian I.; Wooler, G. H.; Smith, D. R.; Grimshaw, V. A.

doi:10.1136/thx.22.4.305

Cited by 54 publications

(11 citation statements)

References 45 publications

(21 reference statements)

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“…The flange suture ring enables the valve to be inserted in precisely the same manner as any other prosthetic valve, using a single row of interrupted sutures. The present clinical series already reported in the world literature (O'Brien et al, 1967;Ionescu et al, 1967) and our own observations lead us to consider that there is promising evidence for continuing investigations in this field. Much work remains to be done in studying the best method of mounting the aortic heterograft (or homograft) so that the frame surrounding it is well incorporated with the tissues of the heart.…”

Section: Discussionsupporting

confidence: 61%

Mitral valve replacement in dogs using pig aortic valve heterografts

Hamilton

Gerbode

1968

Thorax

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Mitral valve replacement using pig aortic valve heterografts has been performed in 27 dogs, siting the grafts in the 'atrial position'. Buffered acid formaldehyde sterilization offered the advantages that it is simple and, by de-naturing the proteins of the graft, may minimize 'rejection' phenomena. It may offer some self-sterilizing property to the graft within the host post-operatively. The question whether heterograft valves will ultimately calcify remains unanswered. The aortic valve has been shown to function satisfactorily in place of the mitral valve for up to four months, producing normal haemodynamic studies. The 'atrial position' of the graft has the advantage that the left ventricular cavity becomes totally available for its pumping activities. The fate of these animals depended upon developing mitral incompetence around the grafts and thrombus, leading to mitral stenosis, rather than to rejection phenomena. The operation described requires accuracy in orientating the graft. Mounting heterografts (with almost the whole of the aortic wall cut away) in a Dacron-covered metal frame pre-operatively provided a valve in a range of sizes which can be inserted in the same manner as any prosthesis in current use. Methods of sterilization and storage and the ultimate fate of heterografts in vivo require further study. Failure such as calcification will probably not develop suddenly. Such a valve could be replaced if necessary. The continued investigation and clinical use of heterografts appears to be justified when viewed against the uncertain outcome of the other methods of valve replacement.

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Section: Discussionsupporting

confidence: 61%

Mitral valve replacement in dogs using pig aortic valve heterografts

Hamilton

Gerbode

1968

Thorax

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“…The mitral ring changes its size and shape during heart contractions, the atrial and ventricular sizes alter, too; finally the chordae tendineae undergo degeneration. All these factors result in ostial insufficiency [17,14].…”

Section: Discussionmentioning

confidence: 99%

Mitral valve replacement by calf aortic heterograft and its clinical evaluation

Lorkiewicz

Anholcer

Gracz

et al. 1970

Langenbecks Arch Chiv

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The authors present the results of surgical management of patients with mitral valve lesions. In 21 subjects replacement of the mitral valve with calf aortic graft was performed. The heterograft prepared according to O'Brien's technique, and reinforced by a metal-terital ring, was inserted into the mitral ostium. The operative method is described and the enclosed tables show the clinical pre-and postoperative findings based on short term follow-up observations.The absence of any postoperative complications with the inserted heterografts, in contrast to multiple troubles with the use of artificial prostheses, is related to the qualities of biological tissue which seem superior to the plastic grafts. Further observation of the patients and a greater number of cases will enable us to draw more precise conclusions concerning the long term fate of heterografts.

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“…Our experiments were completed before the work of Ionescu, Wooler, Smith, and Grimshaw (1967) was published. These authors reported the use of inverted aortic heterografts in humans as mitral valve substitutes, describing the technique of collecting from pigs, preparing and inserting these grafts into several patients, one of whom died from staphylococcal endocarditis with vegetations covering the cusps of the grafted valve.…”

Section: Discussionmentioning

confidence: 99%

Aortic valve allografts in sheep

Borrie

Hill

1968

Thorax

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Some of the mechanical and biological problems surrounding the use of fresh allograft inverted aortic valves as mitral valve substitutes are described. Certain aspects of the problem have been studied expzrimentally. In three sheep 'fresh' aortic valve allografts were -inserted, using cardiopulmonary bypass, into the main pulmonary artery, and were observed from 5 to 7 months after operation. The animals survived normally. Their normal pulmonary valves remained in situ. The technique is described. At subsequent necropsy, macroscopically the valves were found to be free from vegetation, and the cusps were pliable and apparently normal. Microscopically, the supporting allograft myocardium showed necrosis and early calcification. The valve cusp showed hyalinization of collagen, although beneath the endocardium this hyalinized collagen contained moderate numbers of fibroblasts with no evidence of proliferation. The endocardium and arterial intima of the allograft showed evidence of ingrowth from adjacent normal host endocardial tissues. The allograft itself was invested in a loose layer of fibro-fatty tissue, which, in view of the necrotic state of the graft myocardium, could well have been a reparative reaction rather than a homograft reaction. It is concluded that, although the cusps could function normally, the necrosis of the myocardium might in time lead to late failure of the graft. Further studies with the valve inserted at mitral level are indicated.In earlier communications Borrie and Mitchell (1960) described the use of the sheep in surgical research, and later indicated that it was useful for studying mitral allograft (homograft) valves implanted under conditions of total pulmonary bypass (Borrie, Lichter, and Miller, 1967).These studies on the mitral valve performed in 1966 and tabulated in the second paper had shown that an inverted, fresh allograft aortic valve, inserted via a left thoracotomy and atriotomy, with the animal placed on cardiopulmonary bypass and moderate hypothermia, could readily be implanted at the site of an excised mitral valve. Two techniques for implanting had been used. In the first, the coronary artery ostia of the graft were opened to give three long strips of aortic wall and a broad valvular face presenting towards the left ventricle of the host. These long ends of aortic wall were sutured to the left ventricular wall at the site of the divided papillary muscles. The base of the inverted valve was attached by continuous suturing, reinforced by locking interrupted sutures, to the mitral annulus. In the second technique the coronary artery ostia of the graft were closed by purse-string sutures, and the val-ve was attached below to the mitral annulus and above to the left atrial wall.During the attachment of the allograft valve to the base of the host's anterior mitral leaflet the aorta was temporarily cross-clamped, for we had tested experimentally that the sheep heart will regularly tolerate cardiac anoxia from aortic cross-clamping for 30 minutes at 320 C. with subsequent compl...

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Mitral valve replacement with aortic heterografts in humans

Cited by 54 publications

References 45 publications

Mitral valve replacement in dogs using pig aortic valve heterografts

Mitral valve replacement in dogs using pig aortic valve heterografts

Mitral valve replacement by calf aortic heterograft and its clinical evaluation

Aortic valve allografts in sheep

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