Banking of cryopreserved arterial allografts in Europe: 20 years of operation in the European Homograft Bank (EHB) in Brussels.

Vascular allografts have been used for many years in patients with infection complications and when the patient lacks own autologous venous material. Cryopreservation has permitted the long term storage of these allografts, offering the optimal solution for particular clinical situations. For more than 20 years the European Homograft Bank has prepared, stored in the liquid nitrogen vapour below -130 °C and distributed various types of the quality controlled arterial allografts throughout the European centers and elsewhere. The tissues are prepared according to the existing European, Belgian, Swiss and other EU countries' regulations and standards. This paper gives an overview of this activity since 1991. During this period 1,428 batches of arteries were received from recovery centres within European Union and Switzerland and 3,941 arterial segments were evaluated. 1,250 (32 %) were discarded for morphological findings (58 %), bacteriology (31 %) and other reasons, while 2,685 or 68 % (ascending and descending aorta, arch, aortic bifurcation, iliac and femoral arteries and the non-valved pulmonary bifurcations) were cryopreserved and stored. 2,506 arteries were implanted in 1,600 patients in vascular and cardiac centers in European Union and elsewhere. The most important indications were infections (65 %), critical limb ischemia (15 %) and congenital cardiac malformations (15 %). Some allografts were used for the repair of arterial injury (2 %) or prosthetic graft thrombosis (1.5 %). 10 aortic allografts (0.4 %) were used for tracheal replacement in case of cancer. In 52 cases EHB did not fulfill the surgeon's requests due to shortage of arterial allografts. Collaboration with vascular surgeons in the tissue recovery might improve the number, diversity and quality of vascular allografts. A multicentric study is necessary to evaluate the long-term outcome of these allografts.

Belgian and European experience with the European Homograft Bank (EHB) cryopreserved allograft valves.--assessment of a 20 year activity.

European Homograft Bank (EHB) has been selecting, preparing, storing and distributing the cryopreserved allograft valves in Belgium and some other European Countries since 1989. It was established in 1988 by a pathologist and the cardiac and vascular surgeons from Belgian and other European centres as an inter-university, international nonprofit association. Due to its neutral behavior and very high quality criteria, European Homograft Bank became one of the prominent heart valve banks in Europe and wider. It collaborates with the transplant coordination in donor selection as well as with the huge network of the implanting surgeons in Belgium and other European Countries. The EHB responsible discusses with the implanting surgeon the allograft selection on basis of the indication and the patients state of emergency. A total of 8.911 donor heart valves have been evaluated in EHB during the last 20 years. After selection, 5.258 allograft valves (1.996 aortic, 3.189 pulmonary and 73 mitral) were cryopreserved and stored in vapors of liquid nitrogen between 6 weeks and 5 years. A total of 4.516 allograft valves (1.391 aortic, 2.620 pulmonary and 48 mitral) were implanted in the left or right ventricular outflow tract for replacement of the diseased aortic or pulmonary valve and for mitral or tricuspid valve replacement or repair. In 1.380 cases the allograft valves were used for right ventricular outflow tract reconstruction as part of the Ross- procedure, whereas in 668 cases the allograft valve served for replacement of the aortic valve for endocarditis. The most important indications for use of cryopreserved allograft valves were: important cardiac and valve malformation in children, female patients of child-bearing age with diseased cardiac valves, cases with contra-indication for anti-coagulation and the patients with severe endocarditis with septal or annular abscesses. Although the number of the donation increased by year, the available allograft valves in stock are still insufficient to respond to all the surgeons' request for different indications.

Normally and abnormally functioning left-sided porcine bioprosthetic valves after long-term implantation in patients: distinct spectra of histologic and histochemical changes.

This morphologic study (X-ray examination of gross specimens, histologic study and histochemical staining) compares two groups of explanted left-sided bioprosthetic valves: group I, 6 valves with normal cusp function and group II, 10 valves with significant dysfunction. Implantation periods ranged from 26 to 79 months. A computerized descriptive statistical method (principal component analysis) is used to analyze the qualitative results. Although qualitatively identical alterations are observed in both groups, the findings in the deep layers of the cusps of severe collagen breakdown, intensive fibrin penetration and various degrees of calcification are restricted to group II. Other findings of interest in both groups include amyloid deposits (four cases) and layering of fusiform host cells on the cusp surface (three cases). The computerized study shows that individuals of one clinical group are morphologically different from those of the other. Mechanical stress may contribute to surface alterations early after implantation, while further collagen breakdown and macrophagic activity result in deep penetration of plasma components and fibrin. Subsequent calcification is likely to be dystrophic rather than metabolic. Colonization of the cuspal surface by endothelial cells after long-term implantation of bioprosthetic valves expresses a new type of relation between host and bioprosthesis.

Left atrial myxoma associated with systemic AA amyloidosis.

A 76-year-old woman presenting with generalized amyloidosis of the AA-type protein was found to have a left atrial myxoma. Retrospective estimation of the concentration of SAA protein, a serum precursor of AA amyloid, before and after surgical removal of the myxoma, showed that the SAA protein had disappeared after the operation. A common manifestation of myxoma is the development of a severe inflammatory syndrome that sometimes simulates rheumatic fever or bacterial endocarditis. However, to our knowledge, it has never been described in association with amyloidosis. We suggest that atrial myxoma should be added the list of neoplastic and inflammatory diseases predisposing to AA amyloidosis.

In situ hybridization: a new technique to determine the origin of fibroblasts in cryopreserved aortic homograft valve explants.

Tissue degeneration reduces the durability of cryopreserved homografts. Earlier studies indicated that the presence of fibroblasts in homograft leaflets may contribute to increased valve longevity. These fibroblasts may be of recipient origin or represent surviving donor cells. We developed a method, based on in situ hybridization, to determine the origin of fibroblasts in homograft explants. In young pigs we performed aortic valve replacement with a cryopreserved porcine aortic homograft. A male homograft was implanted in a female pig, whereas two male recipients received a female homograft. After 3 to 4 months the homografts were explanted. Frozen sections were made and alternately examined with hematoxylin-eosin staining and in situ hybridization. With a biotinylated porcine Y chromosome-specific deoxyribonucleic acid probe, male fibroblasts could be clearly distinguished from female fibroblasts. In all leaflets we observed both donor and recipient fibroblasts. The distribution of these populations was marked in schematic drawings. Recipient fibroblasts mostly spread onto the leaflet surface but also penetrated the leaflet tissue. Remaining donor fibroblasts did not show morphologic signs of decreased viability on hematoxylin-eosin staining. In situ hybridization may become a useful technique in homograft research. In this porcine model, the fibroblasts in the aortic homograft explants were of both donor and recipient origin.

Morphologic Study of Homograft Valves before and after Cryopreservation and after Short-Term Implantation in Patients.

Cryopreserved heart valve homografts have been implanted in patients for the past 15 years, but controversies still exist on the survival of donor cells, matrix maintenance, and possible rejection by the host. Therefore a full morphologic study (histology, immunohistochemistry, transmission electron microscopy, and cuprolinic blue-TEM for glycosaminoglycans [GAG]) of short-term implanted uninfected grafts was done using unimplanted valves as the reference. Unimplanted tissues consisted of 5 fresh and 11 cryopreserved valves. Eight implants were recovered at reoperation [4] or autopsy [4], 4 from the right and 4 from the left ventricular outflow tract. The implantation time was 2 hours to 30 days. For unimplanted valves we found a partial preservation of the endothelium, the presence of dendritic Langerhans cells (Lc) and macrophages, and no significant damage to fibroblasts, collagen framework, and GAG pattern, except when the tissues had been ischemic for a long time. Explanted cusps exhibited (i) early disappearance of endothelium and Lc; (ii) nonspecific low-grade inflammatory cell infiltration, mostly of monocytoid type; (iii) viable degree of devitalization of fibroblasts with persistence of viable cells in some areas in most cusps; and (iv) fair preservation of collagen framework and GAGs. It is likely that, in view of the good graft preservation at implantation, humoral rejection is responsible for the earlier destruction of the endothelium and dendritic cells and the delayed devitalization of the fibroblasts and that preservation of the collagen framework and other intercellular matrix components (glycosaminoglycans) should guarantee longterm graft function.

Microscopic amyloid deposits in the heart valves: a common local complication of chronic damage and scarring.

The presence of amyloidosis was detected in 33 out of 213 (15.5%) mitral and aortic valves that had been surgically removed for chronic valvular disease. No correlation could be found with age or type of valvular disease, neither was there any clinical evidence of an associated generalised amyloidosis. Histologically, the amyloid deposits were microscopic and restricted to areas of dense scar tissue. No comparable alterations were found in 147 unaltered valves which served as controls. The term 'dystrophic' is proposed to describe this particular form of valvular amyloidosis.

Microdeposits of amyloid in sclerocalcific heart valves: a histochemical and immunofluorescence study.

Amyloid associated with seven sclerotic and two normal aortic and mitral valves was studied. The sclerotic valve amyloid contained microfibrils with typical random orientation and a fibril width of 9.5-12.5 nm. The amyloid deposits demonstrated permanganate-resistant Congophilia and contained the amino acid tryptophan. Immunofluorescence studies showed P-component in amyloid deposits of 6 of 7 valves, but none of the sclerotic valves contained amyloid fibril proteins of the AL (primary), AA (secondary), AEt (medullary thyroid carcinoma) or ASc1 (senile cardiac) types. Two non-sclerotic valves, removed from a patient with systemic amyloidosis, showed permanganate-sensitive Congophilic amyloid deposits which contained amyloid fibril protein AA.

The Ionescu-Shiley pericardial valve: results in 473 patients.

From January 1, 1980, through December 31, 1985, 473 patients underwent valve replacement with an Ionescu-Shiley valve. Overall hospital mortality was 7.8%. Major associated procedures and preoperative New York Heart Association (NYHA) Classes IV and V influenced hospital mortality significantly. The mean follow-up was 2.6 +/- 1.3 years. Late mortality was 5.9%. Overall actuarial survival was 81% at 5 years. A chief cause of reoperation was cusp rupture of a mitral prosthesis in 5 patients (all after aortic and mitral valve replacement). The overall actuarial reoperation-free incidence was 93% at 5 years. Thromboembolic (TB) phenomena occurred at a linear incidence of 1.4 +/- 0.3% per patient-year or an actuarial thromboembolism-free incidence of 92% at 5 years. Univariate and multivariate analyses showed that postoperative NYHA Class, rhythm at follow-up, and anticoagulant therapy significantly influenced the incidence of TE phenomena.

Eradication of aortic infections with the use of cryopreserved arterial homografts.

BACKGROUND: The surgical treatment of vascular infection is associated with a substantial early and late mortality. Cryopreserved homografts were evaluated for in situ reconstruction in aortic infections. METHODS: Between January 1991 and July 1995, homografts were used in 19 patients (mean age, 61 +/- 13 years; range, 40-85 years) with mycotic aneurysms (9/19; 47%) or infected grafts (10/19; 53%) in the thoracic (7/19; 37%) or abdominal (12/19; 63%) aorta. Sepsis was present preoperatively in 14 of 19 (74%) patients, and 18 of 19 (95%) had received antibiotic treatment for 6.4 +/- 6 months (range, 1-36 months). Up to ten previous vascular procedures had been done in 11 of 19 patients (58%). RESULTS: There was one (5.2%) early and two (11%) late deaths, with one (5.5%) of the late deaths being homograft related. The mean hospital stay was 27 +/- 26 days (range, 7-84 days). Antibiotics were given postoperatively for 30 +/- 12 days (range, 4-84 days). During the follow-up period of 18.6 +/- 13 months (range, 7-60 months), there were no instances of reinfection, suture line rupture, homograft stenosis, or anastomotic aneurysms. CONCLUSIONS: Cryopreserved arterial homografts allow safe in situ reconstruction, decrease early and midterm mortality, and reduce antibiotic requirements. Early and midterm reoperations are unnecessary.

Aortic root replacement with a pulmonary autograft in young adults: medium-term results in 70 patients.

BACKGROUND: Pulmonary autograft aortic valve replacement has been introduced in our institution in selected adult patients in light of the known disadvantages and limitations of conventional prosthetic valves. METHODS: We prospectively evaluated the use of the pulmonary autograft in a series of 70 young adults (31.2+/-8.7 years, range 16 to 49 years) operated on from March 1992 to April 1997 with aortic root replacement only. RESULTS: There were no in-hospital deaths and two noncardiac-related late deaths during follow-up of up to 62 months (mean 33 months). Thromboembolic complications were not observed. One patient required reoperation for infective endocarditis 4.3 years after surgery. Discharge echo-Doppler studies showed normal autograft and allograft valve function. Serial echo-Doppler studies showed no significant progression of aortic insufficiency and no dilatation of the autograft. A severe stenosis of the pulmonary allograft developed in 1 patient. CONCLUSION: Aortic root replacement with a pulmonary autograft, although more complex than conventional prosthetic valve replacement, is a safe, effective, and reproducible procedure in properly selected adult patients. Long-term results remain to be evaluated.

Banking of cryopreserved heart valves in Europe: assessment of a 10-year operation in the European Homograft Bank (EHB).

BACKGROUND AND AIM OF THE STUDY: The preparation, banking and distribution of cryopreserved heart valves has been carried out at the European Homograft Bank (EHB) in Brussels without interruption since January 1989. We present an assessment of the Bank's activities during this 10-year period. METHODS: Heart valve donors aged <62 years form three categories: multiorgan donors with non-transplantable hearts; recipients of cardiac transplantation; and non-beating heart cadavers with a warm ischemia time of less than 6 h. Past history and biology are checked for transmissible diseases. Dissection, incubation in antibiotics and cryopreservation in 10% dimethylsulfoxide with storage in liquid nitrogen vapors (about -150 degrees C), and quality control are according to the standards of the Belgian Ministry of Health. Cryopreserved valves are shipped to the implantation centers in a dry shipper at about -150 degrees C. RESULTS: Between January 30th 1989 and December 31st 1998, 1,817 non-transplantable hearts and 12 excised semilunar valves were obtained. In total, 2,077 valves (1,032 pulmonary, 931 aortic and 13 mitral) were decontaminated, cryopreserved and stored in liquid nitrogen vapor (six more valves were refrigerated). In total, 1,515 valves were discarded at different stages of the protocol, the main causes of rejection being significant macroscopic lesions (68.2% aortic and 26.67% pulmonary). Inadequate excision at procurement (10.37% pulmonary), persistent contamination after antibiotics (5.6%) and positive serology for hepatitis B and C and Q fever (5.4%) were other frequent causes for rejection. Among the 2,117 accepted valves, 1,398 were graded first and 719 second choice, mainly on the basis of morphology. In total, 2,090 cryopreserved valves and one refrigerated valve were implanted in 39 institutions between May 1989 and December 1998. Of requests, 10.02% could not be satisfied. In total, 967 pulmonary valves were implanted in the right ventricular outflow tract (RVOT); 424 during a Ross procedure, and 76 in the left ventricular outflow tract (LVOT). Of the aortic valves, 732 were implanted in the LVOT and 266 in the RVOT. Mitral homografts were used for tricuspid valve replacement in two cases, and in the mitral position in seven. Complications at distribution and thawing included 10 bag ruptures and 16 transversal conduit wall fractures. Of the valves shipped, 317 (13.16%) were not used and were returned safely in the dry shipper. Comparison of distribution rates in the first 5.5 and last 4.5 years of EHB activity shows: (i) a significant increase in pulmonary valve implantations in the RVOT (from 71.95% to 81.95%); and (ii) a marked increase (265%) in pulmonary homograft implantations as part of a Ross operation, and a significant decrease (28%) in aortic homograft implantation in the LVOT. CONCLUSION: While macroscopic lesions of procured aortic valves remain the most frequent and unavoidable cause of homograft rejection during quality control, the high percentage of inadequate surgical heart valve excision should be corrected. The rates of bacterial contamination and positive serology seem acceptable. Storage and shipping of cryopreserved homografts in liquid nitrogen vapor permits them to be spared very efficiently. The increasing use of pulmonary valves for RVOT reconstruction either in congenital heart disease or as part of the Ross procedure compensates for the limited availability of good quality aortic valves.

Histopathologic comparison of a pulmonary autograft and pulmonary homograft in a patient 17 months after a Ross procedure: an autopsy study.

BACKGROUND AND AIM OF THE STUDY: The Ross operation has become very popular during the last decade. However little is known about the cellular behaviour of a normally functioning pulmonary autograft. METHODS: This case report deals with a 14-year-old female who died from a non-valve-related cause 17 months after a Ross-Konno operation using a cryop-reserved viable pulmonary homograft for the right outflow tract. Comparison is made between the homologous and autologous pulmonary valves by macroscopic description, histology and immunohistochemistry. RESULTS: The autograft kept its cellular population-except for the dendritic cells which have disappeared, and developed a jet lesion on the ventricular aspect of one cusp as a likely adaptation to a transvalvular gradient. The homograft was extensively devitalized, its cusps being partially covered with a fibrous sheath of recipient origin; few inflammatory cells, consisting of macrophages and rare T lymphocytes were present. CONCLUSIONS: The most puzzling observation, which needs confirmation, is the selective disappearance of the dendritic cells from the viable autograft. It is disappointing that a viable cryopreserved homograft valve has devitalized in the midterm. This phenomenon seems to result from a clinically silent immune reactions.

Multiple aneurysmal dysplasia of pulmonary valvular sinuses with congenital focal aplasia of the annulus.

We report the case of a 22-year-old woman in whom a focal aplasia of the pulmonary valve annulus associated with a multiple aneurysmal compensatory dysplasia was found. This patient had been followed since the age of seven years for a congenital asymmetric hypertrophic cardiomyopathy. Cardiac Doppler analysis showed significant pulmonary valvular insufficiency. The patient underwent heart transplant surgery because of total and refractory cardiac insufficiency. Pathological examination of the explanted heart (at the European Homograft Bank) enabled us to describe this valvular malformation. To date, this anomaly has not been described in the literature. Whether it is a malformation discovered fortuitously, or whether it is responsible in part for some of the signs associated with congenital hypertrophic cardiomyopathy is unclear. However, its role might be disclosed by a rigorous investigation of the patient's family.

Banking cryopreserved heart valves in Europe: assessment of a 5-year operation in an international tissue bank in Brussels.

OBJECTIVE: The heart valve bank of the European Homograft Bank has been set up in 1988 to meet the growing demand of cardiac surgeons for various sized and quality controlled cryopreserved homografts. METHODS: Heart valve donors less than 60 years of age were classified in 3 categories: multiorgan donors with non transplantable hearts, recipients of cardiac transplantation and non beating heart cadavers with a warm ischemic time of less than 6 hours. Past history and biology were checked for transmissible diseases. Preparation, progressive freezing and storage in liquid nitrogen vapors, and quality control were according to the standards of the Belgian Ministry of Health. RESULTS: From end January 1989 to end May 1994, 989 homograft valves were cryopreserved (514 pulmonary, 475 aortic and 3 mitral) whereas 962 valves were discarded. The first cause of rejection being a major macroscopic lesion (41.48%). 138 hearts accepted at inspection were contaminated and 43 cases remained so after antibiotics. 38 cases were positive for hepatitis B or C. Complication at distribution and thawing included 10 instances of bag rupture and 15 of transversal fracture through the wall of the conduit. 477 aortic, 474 pulmonary valves as well as one mitral were implanted between May 1989 and May 1994, either for left or right ventricular outflow tract reconstruction. In the left ventricular outflow tract series 111 aortic and 23 pulmonary homograft valves were used in cases of native endocarditis, prosthetic endocarditis or recurrent endocarditis after homograft implantation. 9.6% of the requests could no be satisfied. Regular follow up information was available from 382 implants-40.1% only. CONCLUSIONS: The assessment of 5 years operation of the heart valve bank indicates: 1) the efficiency of selecting, cryopreserving and allocating quality controlled homograft valves from a large pool of donor hearts provided by a network of hospitals; 2) the difficulty of obtaining regular follow up information on the implants.

Right ventricular outflow reconstruction with homografts.

Ninety children and young adults underwent right ventricular outflow tract (RVOT) reconstruction with aortic or pulmonary homografts from May, 1989 to May, 1994. The patients were divided into three groups according to preoperative diagnosis: RVOT obstructions with ventriculo-arterial (VA) concordance (61), RVOT obstructions with VA discordance (18) and truncus arteriosus (11). Of the reconstructions, 52% were reoperations. A pulmonary homograft was used by preference (85% in the concordant group and 33% in the discordant group). One patient died after homograft correction (hospital mortality 1.1%). The mean follow-up was 32 +/- 22 months. One patient died after 10 months due to congestive heart failure and obstructive pulmonary hypertension. All other patients were in NYHA classes I-II. Three patients (two discordant and one truncus correction) underwent reoperation because of aortic homograft dysfunction and calcification. The incidence of significant (> or = 40 mmHg) gradient across the reconstruction found at the last echocardiographic control was 4% in the concordant, 28% in the discordant, and 18% in the truncus, group. Echocardiographic evidence of moderate (grade 2-3/4) pulmonary regurgitation (PR) was noticed in 24 and 13% of the concordant and discordant groups, respectively. From this medium-term experience it is concluded that (1) the medium-term performance of cryopreserved homografts is excellent, even in young patients, (2) corrections in patients with VA discordance need close follow-up, (3) the use of pulmonary homografts, especially in VA concordant lesions, should be encouraged, (4) longer-term follow-up is necessary to confirm the superiority of the cryopreserved homograft when compared to the porcine xenograft in the RVOT.

The value of the stentless biovalve prosthesis. An experimental study.

Clinical use of the stentless bioprosthesis has not yet been accepted world-wide. Experimental studies are scarce. In a study in growing pigs, 23 aortic valve replacements were performed (7 stented bioprostheses (STB), 10 stentless bioprostheses (SLB) and 6 cryopreserved homografts (CAH)). Valves were studied macroscopically and microscopically after explantation. Five animals died between 1.5 and 4 months after implantation. Two STBs showed extreme calcific degeneration. A third STB animal died suddenly: this STB showed only minimal leaflet calcification. One SLB was stenosed with a large fibrin deposit in one cusp, a second SLB showed slight cusp calcification and three were paracommissural tears in one cusp. In all other animals the valves were explanted after 5 to 6.5 months. All STBs showed severe calcific degeneration. Five SLBs showed mild calcific degeneration, while three others were unaltered after 6 months. All CAHs were free of calcific degeneration, three were perfect, two had a tear in a commisure and another was prolapsed with a fibrin degeneration. The speed and extent of valve degeneration were less than in the STB group. The stentless design is an important contribution which may result in a higher durability of bioprosthetic valves.

Are pulmonary homografts subjected to pulmonary hypertension more appropriate for aortic valve replacement than normal pulmonary homografts? Results of echocardiography in a multicentric study.

OBJECTIVE: To compare the function in aortic position of cryopreserved pulmonary homografts subjected to pulmonary hypertension with that of normal cryopreserved pulmonary homografts. METHODS: Pulmonary valves (52) were implanted in aortic position in different cardiothoracic centres. The valves were classified as follows: Group I-pulmonary hypertension (procured from recipients of heart/heart-lung transplantation, 31 valves), Group II-normal pulmonary pressure (procured from cadavers and multiorgan donors, 21 valves). Regular echocardiographic follow-up was obtained by the implanting centers. Significant echo changes were defined as insufficiency > 2+ and/or stenosis producing a delta P > 30 mm Hg. RESULTS: Pulmonary homografts showed the following significant echo changes: in the Pulmonary Hypertension Group, 7, 27 and 33% at 12, 24 and 36 months, respectively; in the normal PA Group 10, 37.5 and 80% at 12, 24 and 36 months, respectively. In both groups the most common echocardiographic alteration was homograft insufficiency rather than stenosis. Thus, pulmonary homografts subjected to long-term pulmonary hypertension have significantly less echo changes than normal pulmonary homografts, especially after 12 months (chi 2: P < 0.036). CONCLUSIONS: These findings suggest that pulmonary valves subjected to pulmonary hypertension might be more appropriate than normal pulmonary homograft for aortic valve replacement, constituting a possible alternative in case of lack of aortic valve homografts. However, the failure of two out of five valves in the longer term must dictate caution while waiting further long-term results.

Cryopreserved arterial homografts for in situ reconstruction of mycotic aneurysms and prosthetic graft infection.

The management of mycotic aneurysms and prosthetic graft infection of major thoracic and abdominal vessels and infected extra-anatomic bypass remains a problem in vascular surgery. Cryopreserved arterial homografts, being resistant to infection, offer hope for in situ vascular reconstruction in the presence of an infection. We analyzed clinical, microbiological, preoperative and postoperative magnetic resonance imaging (MRI), computed tomography (CT), echocardiography and/or angiography data in 12 patients with mycotic aneurysm or prosthetic graft infection, in whom cryopreserved arterial homografts were used to replace infected segments of major thoracic and abdominal vessels. The hospital mortality was 8.3%. The average postoperative hospital stay was 18 +/- 14.5 days (6 to 45); antibiotic treatment was continued for 31 +/- 12 days (4 to 42). During the mean follow-up time of 18.6 +/- 12.8 months (2 to 48) two patients died, but only one (9%) was homograft-related. Recurrence of infection, suture line problems or homograft stenosis or aneurysm were not observed. Therefore, in situ replacement with cryopreserved arterial homografts is an effective treatment for mycotic aneurysms and graft infection of thoracic aorta, abdominal aortic/iliac vessels and infected extra-anatomic bypass. This operative technique has a low early and late mortality, obviates the need for complex extra-anatomic reconstruction, allows safe in situ repair, reduces postoperative antibiotic requirements, shortens the hospital stay and renders early or medium-term reoperations unnecessary.

Are pulmonary homografts which were subjected to pulmonary hypertension more appropriate for aortic valve replacement than normal pulmonary homografts? A long-term multicentric echography study.

OBJECTIVE: To compare long-term results of the European Homograft Bank (LHB) cryopreserved pulmonary homograft in left ventricular outflow tract (LVOT) subjected to pulmonary hypertension with those subjected to normal pulmonary pressure. The mid-term study of this material published in 1997 showed different results. METHODS: Statistical analysis is calculated by the Kaplan-Meier survival curves, while differences in prevalence by the Log-Rank test. RESULTS: Follow-up (FU) was available in 69 cases (76.7%): 46 in group 1 and 23 in group 2. Five patients have been excluded from the study because of early homograft explantation (technical problems or early valve incompetence). Fourteen out of 43 cases of group 1 (32. 6%) and seven out of 21 cases of group 2 (33.3%) have been explanted after 2.5-88 months and 7-88 months, respectively. Significant echography changes have been found in 19 of 43 (44.18%) of group 1 and 11 of 21 cases (52.38%) of group 2 during the follow-up. Histology showed essentially wear and tear induced lesions. Mean FU was 36.9 (range, 6-88) and 41.3 months (range, 4-88) for group 1 and 2, respectively. No significant difference in the long-term outcome have been found between the two groups (P=0.38). CONCLUSION: Contrary to our previous echocardiography study of mid-term implants the long-term follow up of the PHGs implanted in the LVOT did not show better function of the pulmonary homografts subjected to pulmonary hypertension than those with normal pulmonary pressure. The high failure rate of the PHGs should discourage their use for LVOT reconstruction. Further echocardiography studies of remaining PHGs implanted in the LVOT, and gross and microscopic explant studies are required to judge on the definitive outcome of these grafts.