Aortic valve replacement with homografts. An overview

The implantation of fresh or cryopreserved human heart valves (homografts) in aortic position is a tool in cardiac surgery since 30 years. Homografts are attractive alternatives to the implantation of mechanical or xenobiological prostheses, because anticoagulation can be avoided and a near normal anatomy can be restored. Physicians should know about the several kinds of grafts and operative techniques to adequately take care of the patients in follow-up. This overview on the literature covers methods of harvesting, preparation and conservation of homografts according to standard protocols of the European Homograft Bank in Brussels. Their use in the therapy of human valvular disease is discussed with special emphasis to operative techniques (subcoronary, root) and the Ross procedure and in pediatric surgery. Complications and aspects of postoperative care are discussed including immunologic phenomena. Homografts are useful tools for aortic valve replacement, especially in juveniles, in the presence of contraindications for anticoagulation and in endocarditis. Whereas aortic homografts have excellent long-term results, pulmonic homografts show a significant rate of malfunction. Further studies should be performed to clarify the role of the Ross operation or stentless xenografts compared to homografts in aortic position. In pediatric cardiac surgery homografts are of value especially for the reconstruction of the right ventricular outflow tract. Homografts in mitral position show disappointing results up to now. The major limitation in the use of homografts is the mismatch of availability and request, therefore homografts can only be used for the above mentioned special indications.     

A new method for the preservation of aortic valve homografts.

BACKGROUND AND AIM OF THE STUDY: Aortic valve homografts were treated with 50% ethanol and glycerol followed by freeze-drying (D-Hydro). Comparative results of fresh versus D-Hydro-treated aortic roots implanted for up to nine months in the descending aorta of sheep with induced aortic regurgitation (AR) are reported. METHODS: Six fresh and six D-Hydro valves were implanted in 12 sheep for three, six and nine months, and echocardiography and pressures were taken at surgery and sacrifice. Tissue sections were stained with hematoxylin and eosin, von Kossa, Masson's trichrome, Movat's pentachrome, von Willebrand factor, CD3 (a T-cell marker) and smooth muscle alpha-actin. RESULTS: No grafts had increased gradients after implantation, or at sacrifice. At explantation, fresh homografts showed early pannus formation followed by thrombus, annular dilatation and wall calcification. Leaflets were thickened and progressively retracted. All had severe AR. The appearance of D-Hydro-treated homografts was normal, except for mild leaflet retraction in three, resulting in AR (in two animals the induced AR had healed). Histologically, a T-cell-mediated reaction was evident in the fresh homografts, and collagen distortion was noted. Calcification was present in all fresh specimens and was severe at nine months. D-Hydro roots showed only minor calcification in the six-month samples. Normal collagen, and a complete layer of von Willebrand factor-stained cells were present at three months. At nine months, cell rehabitation extended for two-thirds of the leaflets (alpha-actin +). The inflammatory reaction was very mild, with CD3+-stained cells absent in most samples. CONCLUSION: Aortic valve homografts treated with the D-Hydro freeze-drying method performed better than fresh homografts due to the absence of thrombus and annulus dilatation, limited calcification, and rehabitation of the aortic wall and parts of the leaflet by myofibroblasts, as well as the presence of a complete endothelial layer on the aortic wall and leaflet.     

Transcatheter aortic valve implantation: safety and effectiveness of the treatment of degenerated aortic homograft

Introduction and objectives

Percutaneous aortic valve implantation for patients with severe symptomatic aortic stenosis and a high surgical risk is currently well established. We report our experience in terms of safety and effectiveness of transcatheter aortic valve implantation in other clinical context like the degenerated aortic homografts.

Methods

We report our initial experience in four hospitals and five patients with degenerated aortic homograft and severe aortic regurgitation, refused for surgery for a heart team, that underwent percutaneous implantation of CoreValve^® aortic prosthesis.

Results

We included three males and two females. The mean age was 70 (3.5) years. All patients were symptomatic in New York Heart Association class III or IV. Procedures were performed through one of the femoral arteries in all patients and under sedation in three patients. The implant was successfully carried out in all cases. There were no major complications during the procedure or admission and the valvular defect was solved in all cases. In-hospital and 30-days mortality was 0. All patients had clinical improvement during follow-up with a reduction in at less two grades in the New York Heart Association functional scale.

Conclusions

In our experience the treatment of degenerated aortic homografts and aortic insufficiency with transcatheter aortic valve implantation showed to be safe and effective. The current challenge is to convey the good results of transcatheter aortic valve implantation in symptomatic aortic stenosis and high surgical risk to others disorders of the aortic valve. In the future, it is possible that transcatheter aortic valve implantation will expand its indications to majority of aortic valve disorders and patients with less surgical risk.Full English text available from:www.revespcardiol.org     

Implantation of a xenogeneic stentless aortic bioprosthesis. First experience

To overcome the specific disadvantages of mechanical valves and stented bioprostheses, we implanted a stentless xenogeneic aortic valve in a patient with calcified aortic stenosis. The postoperative study revealed a pressure gradient of 25 mmHg, a minor insufficiency of 10% of total stroke volume and a slightly restricted motion of the leaflets. Although the implantation of a stentless xenogeneic aortic valve is feasible, one should be aware of the specific technical difficulties due to the increased rigidity of the fixed tissue, which is not known in homografts. To our knowledge this is the first report on the implantation of a stentless xenogeneic aortic valve.     

Partial and transient relief of conduit obstruction by low-pressure balloon dilation in patients with congenital heart disease

Seven patients underwent attempted low pressure balloon dilation of stenotic conduits or homografts from right ventricle to pulmonary artery (n=5), in the aortic valve position (n=1), or from right atrium to left pulmonary artery (n=1). In the right ventricle to pulmonary artery group, mean gradient reduction was only 17%. At follow-up, two patients underwent surgical conduit replacement, one had a stent implanted at cardiac catheterization, the other two are awaiting surgical intervention. The patient with a homograft in the aortic valve position had a good initial result but restenosed within 1 year and underwent a pulmonary autograft operation. The patient with the Fontan homograft stenosis had transient obstruction relief but subsequently required stent implantation. Low-pressure balloon dilation of conduits or homografts is only partially and transiently successful. Whether stent implantation will offer better long-term results remains to be determined.     

Bentall procedure using cryopreserved valved aortic homografts: mid- to long-term results

The Bentall procedure is the standard operation for patients who have lesions of the ascending aorta associated with aortic valve disease. In many cases, however, mechanical prosthetic conduits are not suitable. There are few reports in the English-language medical literature concerning the mid- to long-term outcome of Bentall operations with cryopreserved homografts. Therefore, we reviewed our experience with this procedure and valved homografts. From January 1997 through December 2002, 21 patients underwent a Bentall operation with cryopreserved homografts at our institution. There were 14 males and 7 females; the mean age was 36 +/- 21 years (range, 15-74 years). Eleven patients had undergone previous aortic valve surgery. All patients had aortic dilatation or aneurysms involving the ascending aorta. Indications for surgery included aortic valve stenosis or insufficiency, and aortic valve endocarditis (native valve or prosthetic). One patient had Takayasu's arteritis and 3 had Marfan syndrome. There was 1 hospital death (due to sepsis), but no other major postoperative complications. The mean hospital stay was 14 +/- 7 days. Follow-up echocardiographic and computed tomographic scans were performed yearly. The mean follow-up was 34 months (6-72 months). Follow-up imaging revealed no calcifications or degenerative processes related to the homograft. Four patients had minimal valve regurgitation. Two patients died during follow-up. The 3-year actuarial survival rate was 85.7%. Our data suggest that the Bentall procedure with a valved homograft conduit is a safe procedure with excellent mid- to long-term results, comparable to results reported with aortic valve replacement with a homograft.     

Homograft aortic valve replacement--the experience of one unit

BACKGROUND: Homograft valves offer advantages including avoidance of anticoagulation and less susceptibility to infection especially in the setting of endocarditis. However, there is concern about their durability and possible accelerated degeneration particularly in cases of second time replacement with homografts. AIM: This study aimed to evaluate the pattern of homograft failure and the quality of life in patients after homograft implantation. METHODS: Between 1990 and 1998, 58 patients underwent aortic valve replacement with a homograft (aortic homograft = 47, pulmonary homograft = 11). Evaluation was based on clinical and echocardiographic examination, patient questionnaires and explanted valve pathology. Survival and freedom from cardiac related death were expressed by actuarial methods. RESULTS: Follow up ranged from 1 to 10 years (mean 5.5 years). Analysis of questionnaires revealed 60% of respondents to be in good performance status and 20% in moderate and 20% in poor performance status groups. Eleven patients (18.9%) required subsequent redo valve replacement after initial homograft insertion (pulmonary = 6, aortic = 5) due to either valve dehiscence (n=4) or valve degeneration (n=7). The mean interval of re-replacement was 5.4 years. CONCLUSIONS: Pulmonary homografts have a high failure rate in the aortic position. Overall subjective and clinical improvement after surgery is less than expected for a "physiological" device. In the setting of low availability of homografts the use of off-the-shelf devices such as stentless xenografts may be preferable in most cardiac surgical units in the current era.     

"Fresh", antibiotic sterilized aortic homografts in extracardiac valved conduits. Long-term results

Between 1971 and 1980, 65 children, aged 2 weeks to 15 years (mean 6.8 years) had "fresh" antibiotic sterilized aortic homografts inserted as a valved external conduit. Thirty-six patients (55%) had undergone previous palliations. Operations were performed on cardiopulmonary bypass, with hypothermia and cardioplegia. In selected young infants, deep hypothermia with circulatory arrest was used. Twenty-five patients (38%) died after the operation. Mortality was related to the complexity of the lesion, the condition of the child on admission, and the degree of pulmonary vascular disease. In addition, there were 7 late deaths. Twenty-one patients were recatheterized, either as a part of routine postoperative assessment (13) or because of symptoms (8). Satisfactory conduit performance, judged by the absence of significant gradients or regurgitation, was found in 18 out of 21 restudied patients. Calcification of the homograft aortic wall was seen on chest X-ray in 56% of patients. The aortic valve calcified in only one child, following an episode of subacute bacterial endocarditis. We conclude that fresh antibiotic preserved aortic homografts perform well in extracardiac valved conduits. They are easy to insert and better hemostasis can be achieved. Degeneration of the valved leaflets is extremely rare.     

Aortic root enlargement with glycerol-preserved homologous dura mater patch during aortic valve replacement

Aortic root enlargement with a patch is sometimes indicated either to prevent aortic homograft valve distortion during implantation or to facilitate easy, tension-free closure of the aortotomy. Patches made of prosthetic material have been widely used for this purpose. The use of autogenous pericardium has recently been reported. Although dura mater has been shown to have great strength, low antigenicity, athrombogenicity, easy availability in large sizes and rapid bonding to most tissues, its use for patch enlargement of the aortic root has not been previously documented. From 1979 to 1983, 38 patients had dura mater aortic root gussets placed during aortic valve replacement at the Southampton General Hospital. In all cases, the patches were placed to facilitate aortic closure, or to prevent homograft valve distortion by enlarging the non-coronary sinus. Aortic homografts were implanted in 11 patients, Carpentier Edwards' Xenograft valves in 16, Bj?rk-Shiley valves in 8 and Wessex Xenografts in 3 patients. All the patients survived and in a mean follow-up of 30 +/- 12.8 months (range 3 to 48 months) there has been no clinical evidence of patch failure due to leakage, rupture or aneurysm formation. These results suggest that glycerol-preserved dura mater is a satisfactory patch material for aortic root enlargement during aortic valve replacement.     

Aortic valve replacement by a pulmonary homograft

Minor experience still exists in our country with regard to the use of valve homografts in cardiac surgery. Only a few implantations have been performed in cases of right ventricular outflow tract reconstruction in addition to our own experience in cases of infective endocarditis of the aortic valve. We present a case of aortic valve replacement by using an antibiotic-sterilized fresh pulmonary valve autograft. The case is described and the possible advantages of the use of pulmonary allografts in the aortic position are discussed.     

Management of infected vascular prostheses. The vascular homograft revisited

Treatment of infected aortic femoral grafts is difficult and controversial. We describe the case of a patient who presented for recurrent infections of an aorto-bifemoral prosthesis. An arterial homograft was used to replace the Dacron prosthesis. One year later, the patient is free of symptoms and is doing well. Although early experiences with long-term use of homografts showed late degeneration of the grafts, 2 points should now be raised in favor of homograft use: new techniques of fresh antibiotic storage of homografts appear to have improved durability; and if replacement of a homograft ever becomes necessary, implantation of a Dacron prosthesis could likely be performed in an aseptic environment. While the use of homografts may constitute a reasonable alternative for treating patients with infected vascular grafts, firm conclusions cannot be drawn until we have seen larger series of patients and longer follow-up periods than those few reported to date.     

Stentless Xenograft Implantation in Aortic Position in a 7-Year-Old Girl

Disease or dysfunction of the aortic valve in pediatric patients presents a substantial challenge. Valve preservation, even if not the definitive solution, is always optimal. Successful repair will enable somatic growth and avoid repeated valve replacement and the need for systemic anticoagulation. When repair of the aortic valve is not possible in pediatric patients, replacement of the valve requires the most suitable (or, often, the least unsuitable) choice for each patient. The limitations of the typical replacement options (pulmonary autografts, mechanical valves, stented bioprostheses, and homografts) have led us to explore the use of stentless xenografts.Herein, we present a case of aortic valve replacement with a stentless porcine xenograft in one of the youngest and smallest patients reported to date. Use of the xenograft enabled a proper fit with a small aortic annulus, precluded the need for subsequent systemic anticoagulation, and averted a transvalvular gradient and the creation of 2-valve disease. We believe that the stentless porcine xenograft is feasible for use in pediatric patients who require aortic valve replacement.Key words: Aortic valve/pathology/surgery/transplantation, bioprosthesis, cardiac surgical procedures, disease-free survival, heart valve diseases/surgery, heart valve prosthesis implantation, postoperative complications/prevention & control, prosthesis design, risk factors, treatment outcomeDisease or dysfunction of the aortic valve in pediatric patients presents a substantial challenge. Valve preservation is always the optimal solution, if not definitive. Successful repair enables somatic growth and avoids the need for repeated valve replacement and systemic anticoagulation. In patients who are not amenable to primary repair, options include implantable pulmonary autografts (by means of the Ross operation), mechanical valves, stented bioprostheses, and homografts. Each option has considerable drawbacks, which led us to explore the application of stentless xenografts in the pediatric population. Here, we report the case of one of the youngest and smallest patients to have received a stentless porcine xenograft (Freestyle®, Medtronic, Inc.; Minneapolis, Minn) in the aortic position.¹     

Long-term results after aortic valve replacement in patients with congestive heart failure. Homografts vs prosthetic valves.

OBJECTIVES: The aim of this study was to assess the influence of valve substitute (homograft vs prosthetic valve) on the long-term survival and late valve-related complication rates following aortic valve replacement in patients with aortic valve disease and congestive heart failure. BACKGROUND: The effect of choice of valve substitute on outcome after aortic valve replacement in patients with pre-operative heart failure is unknown. The superior haemodynamic profile of homografts may be of particular benefit. METHODS: We retrospectively analysed pre-operative, operative and follow-up data on 518 adults in functional classes III and IV, who, over the 25 years 1969-1993, had their initial aortic valve replacement at Harefield hospital. Follow-up conducted during 1996 to April 1997 and totalling 4439 patient-years was 96.1% complete. Using multivariate analysis, independent risk factors for different complications and mortality were defined. RESULTS: Overall 5-, 10- and 20-year survival was 80+/-2%, 62+/-2% and 30+/-3%, respectively, with no significant difference between valve types. However, homografts (n=381) independently reduced the rate of serious complications and cardiac death, whereas mechanical valves were an independent adverse risk factor for late mortality. The rates of anticoagulant-related bleeding and thromboembolism were increased by mechanical valves, whereas primary tissue failure was the main complication of homografts. CONCLUSIONS: Long-term outcome of homograft aortic valve replacement in patients with congestive heart failure is acceptable, with a reduced rate of serious complications and cardiac death. Further improvements would be expected if the rate of primary tissue failure could be reduced.     

Pseudoaneurysm following aortic homograft: clinical implications?

OBJECTIVE--To determine the prevalence of pseudoaneurysm formation after aortic (left ventricular outflow tract) homograft implantation and to evaluate predisposing factors. METHODS--Echocardiographic data were analysed in 30 patients for evidence of pseudoaneurysm formation after homograft implantation. Pseudoaneurysm was characterised as a perfused echo-free space between the homograft and the native aortic wall communicating with the left ventricular outflow tract. Clinical data were analysed for potential predisposing factors for pseudoaneurysm formation. RESULTS--Pseudoaneurysms were found in 22 of 30 patients. Mean age, length of follow up after surgery, aortic systolic pressure gradient (15 (SD 12) v 10 (4) mm Hg), aortic root diameter, and size of the homografts were comparable in patients with and without pseudoaneurysm. preoperative infection, operating techniques, and whether first or reoperation did not affect pseudoaneurysm formation. However, pseudoaneurysms were often localised at the site of an abscess or a paravalvular leak after eradicated prosthetic valve endocarditis. CONCLUSIONS--(1) Doppler echocardiography demonstrates that pseudoaneurysm formation is common after aortic homograft implantation. (2) A prospective study is needed to clarify the prognostic importance of pseudoaneurysms. (3) The high incidence of pseudoaneurysm formation may lead to an improvement of surgical technique (application of fibrin glue).     

Implantation of two self‐expanding aortic bioprosthetic valves during the same procedure—Insights into valve‐in‐valve implantation (“Russian doll concept”)

Transcatheter aortic value implantation has gained acceptance as a treatment for elderly patients considered high risk for surgical aortic valve replacement. There are still, however, many unresolved clinical and technical issues. The occurrence of transcatheter aortic valve‐in‐valve implantation has been reported anecdotally. Aside from a single case report, there is little literature on this topic. This study was conducted to evaluate the procedural, imaging, and clinical outcomes of patients who underwent transcatheter valve‐in‐valve implantation with two self‐expanding aortic valve bioprostheses during the same procedure. We discuss also the potential valve of on‐line quantitative angiography for assessing the depth of valve implantation and the need to implant a second valve. © 2009 Wiley‐Liss, Inc.     

The influence of stenting on the behavior of amino-oleic acid-treated, glutaraldehyde-fixed porcine aortic valves in a sheep model

BACKGROUND AND AIM OF THE STUDY: The durability of freehand-sewn aortic valve homografts used for valve replacement in humans is greater than for stented aortic homografts. In analogy with this, it is expected that the durability of a stentless heterograft will be superior to that of its stented counterpart. Our objective was to investigate the influence of stenting on amino-oleic acid (AOA)-treated, glutaraldehyde-fixed porcine aortic valve bioprostheses. METHODS: Twelve young sheep underwent implantation of porcine aortic valves in the pulmonary artery: six porcine aortic stentless valves (Freestyle) and six porcine aortic stented valves (Mosaic). In each series, three valves were explanted after three months, and three after six months. Valves were analyzed by gross inspection, radiography, histology, and transmission electron microscopy. Quantitative determination of calcium content was made with atomic absorption spectrometry. RESULTS: The porcine aortic stentless valve showed extensive calcification of its aortic wall portion, but had perfectly functioning, pliable cusps without calcification up to six months. The cusps of porcine aortic stented valves were also pliable and functioning without calcification up to six months. Only minimal calcification was seen in the aortic wall of the stented valves. At six months after implantation the cusps of stentless valves contained significantly less calcium than those of stented valves (2.7+/-1.2 microg/mg and 7.9+/-2.3 microg/mg, respectively; p = 0.011). However, the aortic wall from stentless valves contained significantly more calcium than that of stented valves (three-month explants: 39.2+/-14.4 versus 7.2+/-2.8 microg/mg; p <0.05; six-month explants: 49.3+/-14.0 versus 14.1+/-5.9 microg/mg; p <0.05). CONCLUSION: These data suggest that stenting does influence cuspal calcification of AOA-treated, glutaraldehyde-fixed porcine aortic valves.     

Ten years' experience in aortic valve replacement with homografts in 389 cases

BACKGROUND AND AIM OF THE STUDY: Aortic valve replacement using homografts is an accepted alternative to the use of other replacement devices, and has been established at the authors' institution for more than 10 years. METHODS: Since 1992, a total of 389 homografts was implanted, and 332 patients (mean age 54 years, 72% males) were followed up. The initial patients (n = 75) had subcoronary implantation, all subsequent patients had root replacement. Both aortic grafts (AG) and pulmonary grafts (PG) were used. Follow up was conducted with regard to the factors 'graft origin', 'implantation technique' and 'gender', and included clinical examination, ECG and transthoracic echocardiography on an annual basis. RESULTS: Overall 30-day mortality was 5.4% (AG patients 3.9%, PG patients 13.5%; p = 0.09). Among late deaths (n = 22), six were valve-related (all prosthetic infection). Four minor thrombembolic events were recorded due to amaurosis fugax and transient ischemic attacks (TIA). Freedom from reoperation was 86.5%. Indication for graft replacement was greater after subcoronary implantation than after root implantation (p = 0.04). Reoperation was necessary in 24 patients due to restenosis (n = 4), regurgitation grade >II (n = 5), paravalvular leak (n = 2) and prosthetic infection (n = 13). At the latest echocardiographic follow up, mean peak pressure gradient was 15.60 +/- 11.76 mmHg, homograft regurgitation grade was 0.82 +/- 0.66, left ventricular end-diastolic diameter (EDD) was 49.1 +/- 7.54 mm, and mean aortic root diameter was 30.54 +/- 5.48 mm. When comparing parameters at a mean of five years postoperatively, the pressure gradient increased from 10.26 to 15.02 mmHg, regurgitation grade increased from 0.53 to 0.81, and EDD decreased from 52.3 to 50.4 mm. Other variables showed no significant differences. CONCLUSION: The present results confirmed good midterm-results for aortic valve replacement with homografts. These prostheses are vulnerable to infection, and root replacement was superior to the subcoronary implantation technique.     

Early and long-term outcome of aortic valve replacement with homograft versus mechanical prosthesis—8-year follow-up study

Background: Aortic valve disease is an important and frequent clinical problem with a mortality rate as high as 50–80% in a 5-year natural history of patients with severe aortic valve disease. Biological or mechanical prosthesis implantation is the only way to improve prognosis. Hypothesis: The aim of our study was to assess the clinical outcome of aortic valve replacement according to the underlying valve pathology and the type of replacement device, that is, aortic homografts versus mechanical prostheses. Methods: The study group consisted of 143 patients with a mean follow-up period of 4.1 ± 2.7 years. All patients had annual clinical and Doppler echocardiographic evaluation. Results: Total 8-year mortality was 4.9% (7/143) including early mortality of 1.4%. Eight-year survival probability was not significantly higher in the homograft than in the mechanical prosthesis recipients. No differences were found among subgroups with aortic stenosis, insufficiency, and combined disease. Overall early and late complication rate (13.3 and 24.8%, respectively) was similar in homograft and mechanical valve recipients. The most common late complications were ventricular arrhythmia (10%) (Lown class I–III), pre-dominantly in the homograft recipients (17.7 vs. 3.7%), and heart failure (9.2%), more frequent in mechanical valve recipients (14.8 vs. 1.6%). Thromboembolic events occurred in 6.3%, infective endocarditis in 4.2% (more common in mechanical valve recipients), serious bleeding in 3.7% (only in mechanical valve recipients). There was no significant difference in early and late complication rate among subgroups (aortic stenosis, insufficiency, and combined disease). Of the patients studied, 91.6% improved in functional status after surgery, with significantly better outcome in homograft recipients. The type of preexisting valve disease did not influence clinical improvement. Conclusion: Early and late mortality as well as estimated probability of survival and hemodynamic improvement at 8-year follow-up after aortic valve replacement are independent of the type of implanted valve. Complication rate does not depend upon the type of preexisting valve pathology, but severe late complications are more common after mechanical valve implantation than after homograft implantation.     

Acute aortic endocarditis with annular destruction: assessment of surgical treatment with cryopreserved valvular homografts.

BACKGROUND AND AIM OF THE STUDY: Valve ring abscesses in acute infective aortic endocarditis have a low, though not insignificant, prevalence. Surgical treatment with implantation of prosthetic valves may lead to major life-threatening complications, such as recurrent endocarditis and partial or complete prosthetic dislocation. Valvular homografts may offer a higher resistance to recurrent infection and have thus become recognized as an excellent and safe substitute for orthotopic left ventricular outflow reconstruction. METHODS: Between May 1991 and July 1996, 25 patients underwent surgical treatment for aortic endocarditis with annular destruction. Staphylococcus spp. were present in 32% of patients and Streptococcus spp. in 48%. Seven aortic valve replacements (AVR) and 18 aortic root replacements (ARR) were performed using cryopreserved valvular homografts. All grafts were implanted in the subannular position. RESULTS: The overall outcome was good in 23 patients, two died in the early postoperative period. Mean follow up was 38 +/- 18 months (range: 14 to 76 months). No recurrence of endocarditis was detected and no significant alterations of the implants were described. Transvalvular gradients were significantly lower in ARR patients than in AVR patients. CONCLUSIONS: Despite the severity of the tissue damage, cryopreserved homografts, when implanted in the subannular position, constitute a safe and reproducible surgical treatment of aortic endocarditis with annular involvement.     

Homografts for mitral valve replacement in florid endocarditis--an alternative to prosthetic replacement]

INTRODUCTION: Homografts for valve replacement are indicated in acute valve endocarditis. It is assumed that they possess anti-infective properties. Homografts are an established indication in aortic valve replacement. We present our early results with homografts for mitral valve replacement in acute endocarditis. PATIENTS AND METHODS: Between July 1996 and March 1998 we used cryopreserved homografts for mitral valve replacement in seven patients. In three cases (age 24, 42, and 34 years) the indication was an acute endocarditis with subsequent severe mitral valve insufficiency. The size of the required homograft was measured preoperatively using transesophageal echocardiography. For implantation the technique described by A. Carpentier was used; for stabilization of the mitral anulus a valvular ring (Physio) was implanted. Follow-up was done every six months including clinical and echocardiographical examinations. After the first postoperative year an Ultrafast-CT was done in addition. RESULTS: One patient had complete mitral valve replacement, in the other two cases the diseased parts of the valve were completely excised and the valve was repaired using a partial homograft. There were no perioperative deaths. In the follow-ups, up to 24 months of uneventful homograft function was documented by echocardiography; no insufficiency > degree I was seen on color Doppler echocardiography. At the last follow-up (mean follow-up 16 months, range 12 to 24 months) the average mitral valve orifice was 2.5 +/- 0.5 cm2, the mean pressure gradient 2.8 +/- 0.8 mm Hg. In Ultrafast-CT no morphological abnormalities of the mitral valves and no dilatation of the left ventricle were seen. There were no signs of a recurrence of the endocarditis in any patient during the follow-up period. CONCLUSION: Homografts for mitral valve replacement are an interesting alternative to prosthetic valve replacement, especially in younger patients. In cases with acute endocarditis, in which mechanical prosthesis should not be used, a reconstruction or repair of the mitral valve with preservation of the ventricular geometry is possible even if large parts of the mitral valve are infected.