Mitral valve replacement with stored inverted pulmonary homograft valve

The fate is described of 11 patients who had a stored pulmonary valve homograft mounted on a frame or in a Dacron jacket used for mitral valve replacement. Mitral regurgitation due to holes in the attenuated cusps occurred in nine by one year, requiring re-operation or causing death. Only one patient remains well with moderate mitral regurgitation after two years.     

Medium-term results of aortic valve replacement with cryopreserved homograft valves: importance of a domestic homograft valve bank

There are advantages to using aortic homografts as aortic valve replacements (AVR), particularly in patients with complex infective endocarditis. To determine the importance of a domestic homograft valve bank, our 23 surgical cases of homograft-AVR were reviewed. Since 2000, the Tissue Bank of the National Cardiovascular Center has supplied 23 aortic homograft valves for the treatment of complex aortic valve endocarditis. Fourteen of 23 patients had prosthetic valve endocarditis and 20 patients had an aortic annular abscess. The early mortality rate was 17% (4 patients), in all of whom prosthetic valve replacement had been performed previously. No recurrent endocarditis and no recurrent aortic regurgitation were noted at medium-term follow-up. An aortic homograft valve is the conduit of choice in cases of infective endocarditis and the importance of a domestic homograft valve bank should be recognized.     

Establishment of a bank of cryopreserved valve homografts and clinical use in ninety-two patients]

Good long-term results obtained with homologous valve grafts, specially for correction of congenital cardiac defects, prompted us to create a local cryopreserved homograft bank. A 5-year experience is described, including indications for harvesting, techniques of preparation, cryopreservation and thawing. During this period, 195 homografts entered the bank and 92 were used. Among these 92 clinical cases, 74 consisted of right ventricular outflow tract reconstruction (47 valved conduit and 27 monocusp bearing patch) and 17 were left ventricular outflow tract reconstructions (11 free hand aortic valve and 6 aortic root replacement). Only one case was a tricuspid replacement with a stented homograft. Short-term results, with these homografts, are satisfactory and are compared with long-term results reported in the literature. The authors insist on using very thorough techniques and constant quality control. New developments should include viability control and immunological studies.     

Transcatheter versus surgical valve replacement for a failed pulmonary homograft in the Ross population

Background

Patients who undergo the Ross procedure are at increased risk of pulmonary valve (PV) homograft dysfunction. For those who require reintervention on the homograft, transcatheter PV replacement (tPVR) provides a less invasive therapeutic option than surgical PVR (sPVR). We examined the outcomes following tPVR versus sPVR in a cohort of patients who underwent the Ross procedure.

Pulmonary position cryopreserved homografts: durability in pediatric Ross and non-Ross patients

OBJECTIVE: The purpose of this study was to evaluate the outcome and risk factors for implant failure in pediatric patients who underwent pulmonary position homograft placement for right ventricular outflow tract obstruction compared with conduit placement as a component of the Ross operation. Actuarial 5-year survivals for cryopreserved right ventricle-to-pulmonary artery homografts range from 55% to 94% at all ages. It is not known whether there is a difference in homograft durability when utilized for right ventricular outflow tract obstruction or as part of the Ross operation. METHODS: The records of all pediatric patients receiving a right ventricle-to-pulmonary artery homograft from July 1989 through October 2003 were reviewed. Ninety-eight consecutive patients were studied (26 Ross, 72 non-Ross). In addition to Ross versus non-Ross comparisons, other potential risk factors for homograft failure analyzed included age at operation, follow-up time, type of surgery, and homograft type and size. RESULTS: Ross and non-Ross patients were comparable in age at the time of the operation and follow-up time. Homograft failure rates were 12% and 51% for Ross and non-Ross patients, respectively. Freedom from reintervention was 93% in the Ross and 66% in the non-Ross group at 5 years (P = .019). On multivariate analysis, non-Ross operation and age less than 2 years were significant predictors of homograft failure. CONCLUSIONS: 1. Pediatric patients undergoing the Ross operation have longer homograft survival than pediatric patients treated for right ventricular outflow tract obstruction, independent of age. 2. Homografts placed in patients less than 2 years of age have shorter homograft survival.     

Clinical experience with heart valve homografts in Brazil

The purpose of this paper is to describe the development and progress of the first heart valve homograft bank in Brazil as well as to report the 5-year clinical results. The bank was started in 1995 and employs modern techniques of cryopreservation. Organ procurement increased from 11 hearts in 1995 to 138 hearts in 2000. In the beginning of the experience, only 2 hospitals were using these valves, but this increased to 18 centers in 2000. Clinical experience at the major center includes 117 cases of the Ross procedure, 62 aortic homograft implantations, and 18 cases of mitral homografts. Five-year survival after the Ross procedure was 99.1%, and survival free from any kind of complication was 88.8%. No patients are on anticoagulants, and the incidence of thromboembolism was null. We conclude that auto- and homografts are probably the best alternative to aortic valve replacement for young patients in developing countries.     

Ventricular outflow tract reconstructions with cryopreserved cardiac valve homografts. A single surgeon''s 10-year experience.

OBJECTIVE: From January 1, 1985 through December 31, 1994, one surgeon implanted cryopreserved valved homografts into 149 patients--65 since December 1988. This latter series (II) was accomplished in a single hospital, facilitating patient follow-up with biannual echocardiograms. Analysis of these 65 patients is the primary focus of this report; the indications and early surgical results for the two parts of the series (I and II) are compared to assess the evolution of a single surgeon's use of homografts in a mixed pediatric and adult practice. METHODS: Fifty-one variables for each patient (series II) were entered into a computerized database and analyzed (multivariate and univariate) using SPSS 6.1 software (Statistical Products and Service Solutions, Chicago, IL). Cox proportional hazard model was used to identify the independent contribution of each variable for patient mortality and homograft failure. Cumulative survival estimates were made using Kaplan-Meier analysis. Homograft failure was defined as requirement for replacement or death. In series I, there were 41 left ventricular outflow tract (LVOT) reconstructions (31 adult) and 43 right ventricular outflow tract (RVOT) reconstructions (42 pediatric). In series II, there were 55 RVOT reconstructions (52 pediatric) and 10 LVOT reconstructions (7 adult). RESULTS: There were no technical surgical failures. Total surgical mortality rate was 6% (5/84) in series I (3 LVOT, 2 RVOT) and 15% (10/65) in series II (2 LVOT, 8 RVOT) (I vs. II NS; p = 0.11, two-tailed Fisher exact test). By the Cox analysis, only age < 2 years (p < 0.03) and cross-clamp time > 120 minutes (p < 0.05) were significant predictors for death. Age-based survival curves were compared in a sequential bivariate analyses (log rank test) and age < 2 years again was a significant predictor of decreased patient survival (p < 0.006). Actuarial freedom from patient death or reoperation for homograft failure was 82% +/- 7% at 1000 days and 77% +/- 10% at 2000 days. Three patients required re-replacement for homograft failure (5.4%); one of these patients died. The only significant predictor of homograft failure was postoperative endocarditis (p < 0.05). Homograft performance was evaluated by an extensive echocardiography protocol: in surviving patients and homografts, three valved conduits were judged to have severely impaired performance (stenosis or regurgitation), awaiting surgical replacement for a putative total homograft-related structural failures rate of 11% at 5 1/2 years. CONCLUSIONS: Comparisons of series I and II shows, in one surgeon's practice, an evolution away from use of cryopreserved homografts for LVOT reconstructions except when needed for destructive bacterial endocarditis or complex congenital anatomy. Homograft efficacy and durability were similar in RVOT and LVOT positions, with 78.5% of patients surviving at 5 1/2 years; in surviving patients, 89% of homografts have continued to function well. Homografts are not immune to prosthetic bacterial endocarditis, and its occurrence is associated with accelerated deterioration. Cryopreserved homograft valves are an imperfect but satisfactory biological material for specific ventricular outflow reconstructions.     

Aortic valve replacement with frozen irradiated homografts : An 18-year experience

Between May 1968 and April 1981, 339 patients underwent isolated aortic valve replacement using frozen irradiated homografts. All the operations were carried out by the same surgeon (EJMW) using the same technique. Thirty-two patients were lost to follow-up at various stages and the long-term results of the remaining 307 patients are reported. Two hundred and thirty-four were males and 73 females. Their ages ranged between 10 and 75 years, with a mean age of 53. The dominant lesion was aortic stenosis in 195 cases (63.5%), aortic regurgitation in 68 (22.1%), and mixed aortic valve disease in 44 (14.3%). Early mortality was 8.8% and late mortality during the 5–18 year follow-up period was 49.6%. Re-operations for homograft failure were carried out in 112 patients (40%), with an early mortality of 25%. The results are compared with those of other major series using antibiotic sterilized homograft valves.     

Short-term result of aortic valve replacement with cryopreserved homograft valve in the University of Tokyo Tissue Bank

The short-term results after aortic root replacement with 11 cryopreserved aortic homografts was examined. Since 1998, the University of Tokyo Tissue Bank has supplied 11 aortic homograft valves. Nine of the recipients were male, and the average age was 51.2 years. Nine out of 11 patients had suffered from a serious condition of native or prosthetic valve infectious endocarditis. All of the patients underwent aortic root replacement, and the blood type between the patient and the homograft was matched in 8 of the patients. Only 1 patient died (9.1%) in the short-term due to sepsis. The preoperative degree of aortic valve regurgitation in all of the cases was third or fourth while the regurgitation disappeared after the operation in all of them. Thinking of the serious condition of our cases preoperatively, the 9.1% operative mortality was quite acceptable. Long-term follow-up is necessary to estimate the quality of the homografts.     

Comprehensive experience with the Ross operation in Spain.

OBJECTIVE: Although the first pulmonary autograft operations were performed in Spain in 1991, this procedure has gained substantial interest and has been consolidated since 1997. The establishment of the Spanish Registry of the Ross Operation pretends to evaluate the results of this option in aortic valve disease patients in our setting. METHODS: In a yearly fashion, the cardiac surgery departments in Spain currently performing this intervention send data from new patients or follow-ups to the reference center. Preoperative, intraoperative and postoperative data are included in the registry, with special attention to morbidity, mortality, autograft and homograft dysfunction and need for reintervention. RESULTS: Since February 1991 to May 2002, 169 patients have been treated with this technique. The most prevalent aortic disease was regurgitation (72; 42.59%), congenital being the most frequent etiology (108; 63.9%). Four (2.36%) patients required intraoperative aortic counterpulsation. Operative mortality was 2.36% (n=4). Follow-up is 98.7% complete, with an average of 36.08+/-31.09 months (range 1-135), 84 patients (49.7%) were followed for more than 2 years. The autograft remains competent or with trivial to mild regurgitation in 161 patients (95.6%), presenting two (1.18%) with severe regurgitation. The homograft was normal or with mild stenosis in 159 patients (94.07%), presenting five (2.95%) with severe stenosis. Three (1.77%) required reintervention (surgical or interventional) on the right ventricular outflow tract and four (2.36%) required autograft replacement for a mechanical prosthesis. Actuarial survival is 95.99+/-1.65% at 36 months, remaining 92.44+/-2.55% free from reintervention in the same period. CONCLUSIONS: The Ross operation is an increasingly popular surgical option in Spain, and although the number of patients and length of follow-up are still limited, initial results are at least as good as those reported internationally. It is important to continue a close follow-up of these patients to assess the long-term function of auto and homograft. With the available data, we believe that this therapeutic approach is a valid option for selected groups of patients with surgical aortic valve disease in Spain.     

同种异体带瓣大血管移植后钙含量的改变及其意义

目的 探讨同种异体带瓣大血管移植后钙含量的改变及其意义。方法 分为实验组、对照组和同基因组3组。分别于术后2、4、8、12、16周测定CD25和CD40的表达，光镜和电镜观察移植物并测定钙含量。与对照组和同基因组进行比较。结果 对照组CD25和CD40表达水平的高峰在移植后2周，此后逐渐回落，12周后维持在低水平。CsA组在移植后2～4周的表达明显低于对照组（P〈0．01），但8周后的表达水平与对照组差异无统计学意义（P〉0．05）。对照组的钙含量从4周开始升高，此后逐渐升高，在12周达到高峰并进入平台期。CsA组的钙含量显著低于对照组（P〈0．01）。实验组的内皮细胞脱落和-平滑肌细胞的坏死情况较对照组轻。结论 移植后钙含量的变化与免疫排斥互为因果，互相影响。     

Anti-HLA class I antibodies and pulmonary homograft function after the Ross procedure

Background. The Ross procedure provides excellent long-term results in the majority of patients. However, degeneration of the pulmonary homograft in some patients remains an unresolved problem that may be related to immunologic factors. Therefore, we studied the prevalence of antihuman leukocyte antigen (HLA) class I antibodies and echocardiographic results of homograft function at rest.

Methods. Forty-seven patients (37 men, 10 women; 47 ± 15 years) were seen for echocardiography 1.1 to 63.9 months (median, 27 months) postoperatively. The presence of anti-HLA antibodies was tested against a panel of lymphocytes of 50 donors.

Results. Twenty-seven (57%) of the patients produced anti-HLA class I antibodies. No difference in the maximal or mean transhomograft pressure gradient, or in the frequency of homograft regurgitation according to the presence or absence of anti-HLA antibodies was found. However, the right ventricle was slightly but significantly larger in antibody-positive patients (26.3 ± 4.2 versus 30.7 ± 3.5 mm; p = 0.001).

Conclusions. In the first years after the Ross procedure, we could not detect significant evidence of an association between anti-HLA class I antibodies and echocardiographic results of homograft function at rest in adults.     

Procollagen synthesis by fresh and cryopreserved rat pulmonary valve grafts

OBJECTIVE: Allograft valves are frequently used in the repair of congenital cardiac anomalies. The failure rate may differ depending on the type of allograft used. Previous studies have shown that rat aortic valve grafts exhibit synthesis of procollagen, suggesting a capacity for repair and regeneration after implantation. No studies of pulmonary valve grafts in the heterotopic rat implant model have thus far been reported. This study was designed to investigate whether pulmonary valve grafts maintain in vivo viability, as demonstrated by procollagen synthesis, and whether cryopreservation, histocompatibility, or both affect this property. METHODS: Cryopreserved and fresh rat pulmonary valves were implanted into the abdominal aorta of syngeneic and allogeneic recipients. The grafts and native valves were excised 3 to 21 days after implantation. Valves were sectioned and immunohistochemically stained for procollagen. Computerized morphometry was used to calculate changes in intima, media, and adventitia as a percentage of cross-sectional area of the graft. Procollagen content was graded by semiquantitative methods. RESULTS: Pulmonary valve grafts had significantly greater collagen density in the intima and adventitia compared with native aortic and pulmonary tissues, but collagen density in the media was similar in all groups. The grafts demonstrated appreciably greater procollagen than the corresponding native valves. These findings were consistent in all grafts (ie, both fresh and cryopreserved, both syngeneic and allogeneic), irrespective of duration of implantation. CONCLUSIONS: Procollagen synthesis occurs in pulmonary valve grafts early after implantation, indicating viability of these tissues. This model of pulmonary valve implantation may have wide applicability to questions of allograft biology.