Mitral Homograft Research Articles

Mitral homograft replacement of the tricuspid valve for endocarditis

An infected tricuspid valve was successfully replaced with a fresh mitral homograft. This operation is preferable to valvectomy alone or the use of a stented prosthesis in terms of hemodynamics and resistance to infection.

Mitral valvuloplasty and homograft AVR in an undeveloped population and early results

Mitral valvuloplasty and homograft AVR in an undeveloped population and early results

Tricuspid autograft for mitral-valve repair

Summary Background Transferring the posterior leaflet of the patient's own tricuspid valve with its subvalvular apparatus to the mitral valve is a new technique that allows a conservative approach to mitral-valve repair. The technique is based on the knowledge that the tricuspid valve can be remodelled from tricuspid to bicuspid, with a very low risk of significant dysfunction. Methods We describe six patients (age range 20-70 years) with mitral insufficiency in whom we have used the technique. Findings All patients survived the operation and were in sinus rhythm. Transoesophageal echocardiography before discharge showed trivial or no regurgitation at the site of mitral repair. Before operation, all patients were in New York Heart Association class III-IV; at follow-up after 6-13 months all patients were in class I-II Interpretation Compared with using segments of mitral homografts in similar situations, the intraoperative availability of the tricuspid's viable natural chordae and valvular leaflet means that there are no immunological disadvantages to the procedure. With this new operation, the patient is his own tissue bank.

Homograft replacement of the mitral valve: graft selection, technique of implantation, and results in forty-three patients

Because of experience gained in reconstructive mitral valve surgery, we have reevaluated the implantation of cryopreserved homografts in the mitral position. Forty-three patients, aged 11 to 69 years (mean 34 years), underwent mitral valve replacement with cryopreserved mitral homografts. The indications for the procedure were acute endocarditis ( n = 14), rheumatic stenosis ( n = 26), systemic lupus endocarditis ( n = 2), and marasmic endocarditis ( n = 1). All homografts were obtained from hearts explanted in the course of transplantation and were cryopreserved at -160° C in 10% dimethyl sulfoxide solution without antibiotics. Appropriate sizing was based on morphologic study of the homografts and preoperative echocardiographic assessment of the recipient valve. In 82 homografts analyzed, the height of the anterior leaflet was 25 ± 3 mm and the distance from the anulus to the apex of the anterior papillary muscle was 21 ± 3 mm. The morphologic features of the papillary muscles were classified according to four types of increasing complexity. Nine valves with complex (type IV) papillary muscle abnormalities were discarded. Echocardiographic measurements of the valve were matched with those of the homograft identification cards and a slightly larger homograft was selected (measurements + 3 mm). Partial homograft replacement was done in case of a localized lesion (abscess or calcification) ( n = 21). Total homograft replacement was undertaken in the presence of diffuse lesions ( n = 22). Two hospital deaths occurred as a result of poor cardiac output. One patient required reoperation on the tenth postoperative day after a dehiscence on the valvular suture line. After a mean follow-up of 14 months, there has been one late death caused by a bronchial neoplasm and one reoperation for residual stenosis (partial replacement). The remaining patients were in either New York Heart Association class I ( n = 25) or II ( n = 13). Thirty-three patients were in sinus rhythm. Follow-up echocardiography has revealed no mitral regurgitation ( n = 20), minimal mitral regurgitation ( n = 13), and mild mitral regurgitation ( n = 5). Surface valve area has been calculated at 2.5 ± 0.4 cm 2 in partial homograft reconstruction and 2.7 ± 0.3 cm 2 in total homograft replacement, with a transvalvular gradient of 3 ± 4 mm Hg. Conclusion: In a selected group of patients, the use of mitral homografts significantly extended the present limitations of reparative surgery of the mitral valve. (J T HORAC C ARDIOVASC S URG 1996;111:367-80)

Mitral valve repairs using the posterior tricuspid leaflet and chordae. Technique and results.

Some mitral lesions are still out of reach of conventional repairs. Transferring the posterior leaflet of the tricuspid valve with its subvalvular apparatus to the mitral valve is a new autograft technique which has allowed us a conservative approach in cases where repair seemed less predictable. After removing the posterior tricuspid leaflet with its subvalvular apparatus, the tricuspid autograft was inserted by implanting its papillary muscle onto the mitral papillary muscle and then by suturing the leaflet tissue in place. The tricuspid valve was subsequently repaired by annular plication and leaflet suture. A tricuspid ring was used in all but the first case. The age of the seven patients ranged from 20 to 70 years. Postoperative controls by transesophageal echocardiography showed no leaks in five and trivial in one on the site of the mitral repair. On the tricuspid valve, we found a moderate leak in the first case and trivial or none in the following cases, where a tricuspid ring was used. With a 3-12 month follow-up the results are stable. This autograft technique is reproducible, and extends the field of mitral valve repairs. Compared to segments of mitral homografts, we prefer the intraoperative availability of natural chordae and valvular leaflet that have no immunological interference. The patient is his own tissue bank and the tricuspid valve can be repaired with a very low risk of significant dysfunction.

Partial homograft replacement of mitral valve

To date, treatment of mitral valve disease with mitral homograft implantation has been unsatisfactory. We describe two cases of mitral valve repair in man with a cryopreserved partial mitral homograft. Massive mitral insufficiency was surgically corrected by replacement of the severely affected posterior leaflet and the subvalvular apparatus with their corresponding mitral-valve homograft tissue. 22 and 4 months after surgery, the repaired valves remain competent with flexible and normal functioning leaflets and subvalvular apparatus, and the patients are symptom-free.

Mitral valve replacement using a cryopreserved mitral homograft

Mitral valve replacement, using a cryopreserved mitral homograft, was performed in a 49-year-old patient with calcified mitral stenosis. Postoperative course was uneventful. Transesophageal echocardiography performed 6 months later showed normal function of the mitral homograft.

Current status of valvular surgery

Surgical treatment of valvular heart disease is a field of constant clinical and experimental research. Recently, much attention has been devoted to the improvement of valve repair techniques. The physiopathology of the left ventricular outflow tract obstruction following mitral valve repair has become better understood. Surgical techniques to correct this infrequent complication have been developed. Conservative valvular surgery or homograft use are among the surgical treatments for infective endocarditis; innovative experimental and clinical studies on mitral and tricuspid homografts have provided interesting results. New biological valves have come into use; intraoperative creation of a cardiac bioprosthesis using glutaraldehyde-treated autologous pericardium is an attractive surgical innovation. Stentless bioprostheses are also under investigation, to evaluate their hemodynamic and clinical characteristics. The biology of bioprosthesis deterioration progresses at the cellular level, with the implication of phagocytosis as a contributing factor.

Partial replacement of mitral valve by homograft: An experimental study

Satisfactory long-term clinical results with heart valves have renewed the interest in the use of mitral homografts, despite the technical difficulties with their surgical implantation. This report describes the behavior and viability of the partial mitral homograft in the ortotopic position in a chronic sheep model (n = 25). The 20 surviving animals were studied hemodynamically and were anesthetized and electively put to death 3, 6, 9, and 12 months after the operation. All specimens had a normal mitral valve without signs of infection or thrombosis. Light, scanning, and transmission electron microscopy showed the presence of viable endothelial cells from the recipient covering the graft, signs of reendothelialization, and organized dense collagen tissue. The structural integrity was more evident in the fresh mitral homografts. This method may provide consider improvement in the viability of the mitral homograft, and it could be a valid alternative for repair of mitral valve localized pathology.

Pregnancy in patients after valve replacement.

This report is based on information obtained from a questionnaire sent to major cardiac centres in the United Kingdom. This produced details of 39 pregnancies in 34 patients after valve replacement. The 39 pregnancies gave rise to 30 healthy babies. The small size of the series probably reflects both the increasing rarity of young women with rheumatic heart disease in this country and the cautious attitude of their cardiologists. This makes it likely that these women represented the best end of the spectrum of cardiac function after valve replacement. Twenty-four pregnancies in 20 women who were not given anticoagulants producted 23 healthy babies and 1 spontaneous abortion. This group comprised 6 patients with free aortic homografts, 1 patient with a fascia lata mitral valve, 1 with a Beall tricuspid prosthesis, 1 with a combined mitral homograft and Starr Edwards aortic prosthesis, and 1 with mitral and aortic frame-mounted fascia lata valves. There were no maternal deaths or thromboembolic complications in this group which included 5 patients who were in atrial fibrillation. Fifteen pregnancies in 14 women who received anticoagulants gave rise to 7 healthy babies. The fetal losses were one stillbirth, one intrauterine death at 34 weeks, and 3 spontaneous abortions; one surviving child has hydrocephalus as a result of blood clot and there were 2 maternal deaths. This group included 13 patients with Starr Edwards valves, 11 mitral and 2 aortic. A patient with a Hammersmith mitral valve was the only one to have been treated with heparin and her valve thrombosed. One patient with a mounted mitral homograft had a cerebral embolus. Nine of these patients were in atrial fibrillation. In 3 additional patients the valve replacement was carried out during pregnancy. Two of the patients survived operation. In one of these who was treated with warfarin the pregnancy well, but there is an increased fetal wastage in patients pregnancy gave rise to a congenitally malformed baby who died in the neonatal period. The baby born to the mother who did not receive anticoagulants has a hare-lip and talipes. Women with artificial valves can tolerate the haemodynamic load of pregnancy well, but there is an increased fetal wastage in patients taking oral anticoagulants. This is probably largely attributable to fetal haemorrhage but there is also a risk of malformation caused by a teratogenic effect of warfarin. Experience gained in non-pregnant patients suggests that withholding anticoagulatns in pregnant patients with prosthetic valves would usually be undersirable but warfarin should be avoided. The advantages of biological valves were apparent in this series.

Viability of fresh mitral homograft valves.

The present study was undertaken to measure and compare the viability of the mitral leaflet, chordae, and papillary muscle. The viability of the valves was assessed by autoradiography at regular intervals after sterilization and preservation in antibiotics and nutrient medium. The results showed different rates of decline in viability of the leaflet, muscle, and chordae of the mitral valves. Slightly more than 70% of the leaflet fibroblasts took up thymidine during the first 24 hours of storage. This is compared with 68% of papillary muscle fibroblasts and 40% of chordae fibroblasts. Viability of the chordae decreased rapidly and became pronounced at four weeks. One week is the maximum time for storage of mitral valves if it is desirable to preserve living cells in the chordae.

Clinical and hemodynamic studies in patients with homograft mitral valve replacement.

Debate continues regarding the long-term clinical and hemodynamic benefit of homograft replacement of the diseased mitral valve. The results of valve replacement with mitral homografts in the 120 patients who have had operation at the Stanford Medical Center from May 1967 to November 1970 are given. The operative mortality rate has been 5% and the late mortality rate 6%. Anticoagulants were stopped 6 weeks following surgery and there has been only one thromboembolic complication. Ninety percent of the surviving patients are improved clinically. Thirteen of these patients have been restudied 25 to 41 months after receiving homograft mitral valve replacement. Hemodynamic studies showed a 43% decrease in mean left atrial pressure and 42% decrease in mean pulmonary artery pressure with a 10% increase in mean resting cardiac output. Early diastolic gradients between the left atrium and left ventricle averaging 3.0 mm Hg at rest and 6.0 mm Hg during moderate exercise were present. Left ventricular angiography showed a trace of mitral insufficiency in three patients, moderate to severe in three others, and poor contractility in three other patients with normal homograft function. Mitral insufficiency, when present, was thought to result from poor mounting of the homograft on the metal strut rather than primary deterioration of the valve leaflets. These data indicate that fresh homograft replacement of the mitral valve provides good long-term clinical and hemodynamic benefit in most patients.

Replacement of mitral and tricuspid valves by mitral homograft

Replacement of mitral and tricuspid valves by mitral homograft

Replacement of mitral and tricuspid valves by mitral homograft

Replacement of mitral and tricuspid valves by mitral homograft