40 Years experience in mitral valve replacement using Starr-Edwards, St. Jude Medical and ATS valves.

BACKGROUND: We have used the Starr-Edwards ball (S-E) valve since 1963, the St. Jude Medical (SJM) valve since 1978, and the ATS valve, since 1993 as the first choice of mechanical valve. In this study, the results with each valve during the 40 years were investigated in single mitral valve replacement (MVR) cases. PATIENTS AND METHODS: The mean age for S-E valves was 32.8+/-11.1 years old (y.o.), for SJM it was 47.2+/-12.6 y.o. and for ATS it was 56.3+/-11.4 y.o., indicating the aging of patients over time. The operative mortality decreased over the same time from 10.3% to 5.2% then 1.4% respectively. A significant difference was observed among the 3 groups with regards to the valve-related complication-free rate and cardiac event-free rate. However, there was no significant difference among the 3 groups with the other complications. CONCLUSION: Although there are many cases of valve-related complications with S-E valves, they have a role as an initial stage mechanical valve. In view of the long-term results extending over 20 years, the SJM valves is considered as the most reliable valve. The ATS valve is expected to achieve favorable results in the future because it may improve the quality of life (QOL) of patients and produce fewer valve-related complications.     

Long-term results of bioprosthetic valves mounted on flexible stent]

From April, 1984 to April, 1989, 104 heart valve replacements were performed in 103 patients. The atrio-ventricular valves (97 mitral and 7 tricuspid valves) were replace by bioprosthetic valves mounted on the flexible stent made of Elgiloy. They included 91 porcine aortic valves and 13 bovine pericardial valves. Only 74 patients recovered and discharged from the hospital because of high operative mortality of re-replacement and double valve replacement (19 and 30 patients, respectively). These patients were followed-up for 8 to 68 months with a total follow-up period of 297 patient-years. Two patients developed cerebral embolism and two developed bacterial endocarditis. The incidence of the two complications was 0.67%/patient-year. No valve failure occurred. Long-term results of bioprosthetic heart valves mounted on flexible stent were better than those mounted on rigid stent.     

Long-term results of valve replacement in the right side of the heart in congenital heart disease--comparative study of bioprosthetic valve and mechanical valve

Valve replacements in the right side of the heart (TVR and PVR) were done on 16 patients with congenital heart disease, mainly tetralogy of Fallot and Ebstein anomaly. Including reoperations, 19 operations were performed on them and 20 artificial valves were inserted. Ten mechanical valves (7 St. Jude Medical valves, 3 Starr-Edwards valves) and 10 bioprosthetic valves (7 Carpentier-Edwards valves, 3 Ionescu-Shiley valves) were used. Age at valve replacement ranged from 9 to 52 years (mean 23.0 years), and the follow-up period was 1.28-19.8 years (mean 5.7 years). Including 2 sudden deaths, late death occurred in 4 patients, on all of whom mechanical valve replacements were done at the primary operation. Five-year survival rate of all patients was 76.4 +/- 12.1%, and 10-year survival rate was 63.6 +/- 15.4%. All the patients who received bioprosthesis at the primary operation survived at the time of this follow-up study. On the contrary, long-term results of mechanical valve was unsatisfactory with the 5-year survival of 62.5 +/- 17.1%. In spite of anti-coagulation therapy with warfarin, three patients with mechanical valve complicated thrombotic valves, which necessitated re-operations. Calcified bioprosthetic valve occurred in one patient with I-S valve 8.5 years after the implantation. Five-year complication-free rate was 87.5 +/- 11.7% for bioprosthesis, whereas it was 50.0 +/- 15.8% for mechanical valve (p less than 0.056). It is concluded that the bioprosthesis is the first choice for the valve replacement in the right side of the heart in congenital heart disease.     

Tricuspid valve replacement with the St. Jude Medical valve

A study was conducted on 20 patients who underwent tricuspid valve replacement (TVR) with the St. Jude Medical (SJM) valve. Isolated TVR was performed on 9 patients, and additional mitral, or mitral and aortic valve replacements were performed on 11 patients. Four patients (20%) died in the early postoperative period, but there were no deaths related to the SJM valve in the tricuspid position. The mean follow-up period of the 16 survivors was 74.4 months, and there have been no deaths during the follow-up period. The postoperative actuarial survival rate was 80%, 10 years after surgery. Three patients, representing 0.25%/patient-months, developed valve thrombosis, the valve thrombosis-free rate being 72.8%, 10 years after surgery, while entrapment of a leaflet by endothelial pannus was found in one patient, representing 0.08%/patient-months. Thus, the incidence of all prosthetic valve-related complications was 0.34%/patient-months, and the postoperative complication-free rate was 65.3%, 10 years after surgery. The medium-term follow-up study of TVR with the SJM valve revealed no prosthetic valve-related deaths and a relatively low incidence of prosthetic valve-related complications. However, as with other mechanical valves, valve thrombosis was a major risk posed by the SJM valve in the tricuspid position.     

Long-term follow-up of cardiac valve replacement using bioprosthesis in patients 70 years old and older

Good long-term results with the bioprosthetic valves for patients 70 years old and older have been reported. However, because the average lifespan is increasing, we aimed to clarify whether patients older than 70 may still be candidates for valve re-replacement. Seventy-one patients 70 years old and older, who received a total of 81 bioprosthetic valve replacements during 73 procedures between 1988 and 2000, were reviewed. There were 8 hospital and 7 late deaths. Ten-year actual survival after valve replacement was 73.5%, and 82.8% when hospital deaths were excluded. During the follow-up period, 2 patients received mitral valve re-replacement. Ten years of freedom from reoperation were found in 66.7% for all valves and in 50.0% for mitral valves. The average lifespan in Japan is currently 77.64 years for men and 84.62 years for women; therefore, valve degeneration in patients who receive bioprosthesis replacement in their early 70s should be anticipated.     

In vitro hydrodynamic characteristics of heart valves in tricuspid position

At present there are many problems concerning the choice of heart valve for cardiac valve replacement in the tricuspid position. Thus, we devised an attachment head for the prosthetic valve in order to evaluate the hemodynamic characteristics of four clinically-available mechanical prosthetic valves and two xenografts in the pulsatile circulation system in the tricuspid position. Six artificial cardiac valves were used in this experiment; St. Jude Medical (SJM), Starr Edwards ball (S-E), monostrut Bj?rk Shiley (B-S), Omnicarbon, Carpentier Edwards (CE) supraannular, CE-pericardial whose tissue annulus diameter was 27 mm. The experimental instrument similar to that of Umezu et al, was prepared to determine the mean pressure gradient, output and calculated orifice area of each valve. Since many of the patients who must undergo tricuspid valve replacement have severe multi valvular diseases with atrial fibrillation, we experimented also under the condition of atrial fibrillation. At sinus rhythm under pulsation flow, no significant difference was shown in cardiac output between the various valves, but pressure gradient was higher with xenografts than with mechanical prostheses, and the SJM valve showed the widest efficient valve orifice area. The reduction rate of the efficient valve orifice area from sinus rhythm to atrial fibrillation was about 10% in the SJM valve, which was better rate than other heart valves. We observed significant differences in cardiac output, pressure gradient and efficient orifice area at sinus and atrial fibrillation rhythm. (p less than 0.01).     

Prosthetic replacement of tricuspid valve: bioprosthetic or mechanical

BACKGROUND: Tricuspid valve replacement is one of the most challenging operations in cardiac surgery. Selection of the suitable prosthesis is still debatable. METHODS: In our institution, between January 1980 and December 2000, 129 tricuspid valve replacements were performed in 122 patients (14.7%). Bioprosthetic valves were used in 32 patients, whereas 97 patients had mechanical valve implantation. Twenty-two percent of replacements were done on men. Mean age was 35.27+/-11.56 years. In all patients, initially an annuloplasty technique was tried. Tricuspid valve replacement was performed when annuloplasty was not sufficient. In most of the cases, tricuspid valve interventions were done under cardiopulmonary bypass and on a beating heart. RESULTS: Early mortality was 24.5%. Patients were followed for 2 to 228 months. Seven patients underwent reoperation because of tricuspid valve dysfunction (7.6%). Nine patients died during the follow-up period. Late mortality was 9.7%. Actuarial estimates of survival in 20 years of follow-up for all tricuspid prosthetic valves, mechanical valves, and bioprosthetic valves were 65.1%+/-9.3%, 68.3%+/-10.6%, and 54.8%+/-12.1%, respectively. For the bioprosthetic valve group, freedom from structural valve degeneration was 90%+/-5.5%; for the mechanical valve group, freedom from deterioration, endocarditis, and leakage was 97.8%+/-4.2%, and freedom from thromboembolism was 92.6%+/-6.9%. CONCLUSIONS: We found that there was no statistically significant difference between the two groups in terms of early mortality, re-replacement, and midterm mortality (p > 0.05). Nevertheless, we recommend low profile modern bileaflet mechanical valves for prosthetic replacement of the tricuspid valve, due to their favorable hemodynamic characteristics and durability.     

Valve replacement in patients on chronic renal dialysis: implications for valve prosthesis selection

BACKGROUND: Reports are sparse describing heart valve replacement in patients with end-stage renal disease. This review assesses a 15-year experience and outcomes after valve replacement in patients on chronic preoperative renal dialysis. METHODS: A computerized database, hospital records, and telephone contact provided outcome data for patients on chronic dialysis undergoing valve replacement between March 22, 1985, and October 13, 2000, in two hospitals. RESULTS: Seventy-two patients underwent 95 valve procedures (74 operations). Ages ranged from 23 years to 84 years (mean, 57 years). Fifty-five aortic, 30 mitral, and 3 tricuspid valve replacements and 7 valvuloplasties were performed. Six of the 74 procedures were reoperative valve replacements. In the 46 patients with reliable long-term (greater than 30 days) follow-up data, significant bleeding or stroke was documented in 17 of 34 patients with a mechanical valve and 1 of 12 patients with a bioprosthetic valve. Overall survival (including two operative deaths) was 72.8% at 3 months, 65.4% at 6 months, 60.5% at 1 year, 39.8% at 2 years, 28.5% at 3 years, and 15.9% at 6 years (Kaplan-Meier). Type of valve implanted did not influence early and late survival. CONCLUSIONS: In this series of patients on chronic dialysis, survival appears to justify valve replacement. However, the sixfold higher incidence of late bleeding or stroke in patients on dialysis with a mechanical valve requiring warfarin suggests that bioprosthetic valves are the valve substitute of choice in patients on chronic dialysis.     

Evaluation of valve sound and its effects on ATS prosthetic valves in patients' quality of life

BACKGROUND: We interviewed patients and carried out frequency analyses to compare the closing sounds of ATS and St. Jude Medical (SJM) prosthetic valves. METHODS: Forty-five patients undergoing valve replacements using ATS valves were investigated. We interviewed patients at 1 month and 1 year after the operation, and carried out frequency analysis to investigate the prosthetic valve's closing sound. RESULTS: According to the results of the interviews, 84.4% of patients with ATS valves were not aware of the valve sounds. ATS valves scored significantly lower than SJM valves on audibility of the valve sound, disturbance during daytime, sleep disturbance, request for replacement with a soundless prosthetic valve, audibility to others, and noise index. According to the frequency analysis on the prosthetic valve's closing sound, the sound peak of the ATS valves was around 1.2 kHz, and the sound pressure of the ATS valves was significantly lower than that of the SJM valves. CONCLUSIONS: Though a further long-term observation on thromboembolism and hemolysis is needed for evaluation of prosthetic valves, the ATS valve is presently considered to impart a better quality of life.     

Tricuspid valve replacement: an analysis of 25 years of experience at a single center

BACKGROUND: Tricuspid valve replacement is seldom used in clinical practice, but the choice between mechanical and biologic prostheses remains controversial. METHODS: Between 1977 and 2002, 97 patients underwent tricuspid valve replacement and were followed at the Montreal Heart Institute Valve Clinic. Patients underwent replacement with bioprostheses (n = 82) and mechanical valves (n = 15). RESULTS: Patients with bioprosthetic tricuspid replacements averaged 53 +/- 13 years of age compared with 48 +/- 11 years in those with tricuspid mechanical valve replacements (p = 0.2). Isolated tricuspid valve replacement was performed in 11 patients (73%) in the mechanical valve group compared with 31 patients (38%. p = 0.01) in the bioprosthetic replacement group. In patients undergoing bioprosthetic tricuspid replacement, 51 (62%) underwent multiple associated valve replacements. The 5-year survival after tricuspid replacement averaged 60% +/- 13% in the mechanical valve group and 56% +/- 6% in the biologic replacement group (p = 0.8). The 5-year freedom rate from tricuspid valve reoperation averaged 91% +/- 9% in patients with mechanical valves and 97% +/- 3% in those with biologic valves (p = 0.2). CONCLUSIONS; Patient survival after tricuspid valve replacement is suboptimal but related to the clinical condition at operation. The use of biologic prostheses for tricuspid valve replacement remains a good option in young patients because of limited life expectancy unrelated to the type of tricuspid prostheses at long-term follow-up.     

Avoidance of patient-prosthesis mismatch

To minimize the incidence of patient-prosthesis mismatch (PPM), we have routinely adopted aortic root enlargement to avoid PPM for patients with small aortic annulus. The aim of this study was to review our strategy of avoiding PPM. The Carpentier-Edwards Perimount (CEP) valves were implanted in 53 patients who were mostly aged over 65 and the St. Jude Medical (SJM) mechanical valves were used in 128 patients aged under 65. A standard 21-mm SJM valve was used in only 3 patients and no 19-mm valves were employed. However, 19-mm CEP valves were used in 12 patients with a small body surface area (1.43 +/- 0.14 m2). Of these, 26 patients (14.4%) who had a small aortic annulus and 24 patients aged under 65 underwent aortic root enlargement. No patient receiving an SJM valve had an projected indexed effective orifice area (EOAI) < or = 0.85 cm2/m2 because of performing aortic valve replacement (AVR) with annular enlargement and only 2 (3.8%) out of 53 patients receiving CEP valves developed PPM. Consequently, the prevalence of PPM was 1.1% in this series. The prevalence of PPM was low in patients over 65 years old with a relatively small body size who received bioprosthetic valves. A pericardial bioprosthesis was considered to be an appropriate valve in older population with regard to avoiding PPM. In patients under 65 years old with a small annulus, the first choice for avoiding PPM is aortic annular enlargement, which may be avoided by high performance mechanical valves with larger EOA.     

Prosthetic valve replacement in children

Between 1975 and 1998, 27 patients aged 3 months to 14 years underwent replacement of the aortic, mitral, tricuspid, and pulmonary valves. Five different types of prosthetic valves were used; three were mechanical valves and two were bioprosthetic valves. There were 3 hospital deaths. Among the 24 survivors there were 4 late deaths. Arrhythmia requiring pacemaker implantation occurred in 2 cases after AVR and TVR. Thromboembolic events occurred in 3 patients, all with mechanical valves in pulmonary position. Infective endocarditis occurred in 1 patient after PVR with a mechanical valve. No bleeding complication occurred among the patients on a regimen of Coumadin and Dipyridamole. Two patients, both with Hancock bioprosthesis, required a second valve replacement on account of severely calcified changes. Mechanical valves in left side heart had a satisfactory long-term performance. One patient who had undergone MVR for congenital parachute mitral valve received reoperation for growth. A larger sized prosthetic valve should be used at the first replacement, and special procedures including supra-annular positioning or annular augmentation are recommended for MVR or AVR respectively.     

Risk of Reoperative Valve Replacement for Failed Mitral and Aortic Bioprostheses

Background. One factor influencing the choice of mechanical versus bioprosthetic valves is reoperation for bioprosthetic valve failure. To define its operative risk, we reviewed our results with valve reoperation for bioprosthetic valve failure.

Methods. Records of 400 consecutive patients having reoperative mitral, aortic, or mitral and aortic bioprosthetic valve replacement from January 1985 to March 1997 were reviewed.

Results. Reoperations were for failed bioprosthetic mitral valves in 219 patients, failed aortic valves in 153 patients, and failed aortic and mitral valves in 28 patients. Including 26 operations (6%) for acute endocarditis, 153 operations (38%) were nonelective. One hundred nine patients (27%) had other valves repaired or replaced, and 72 (18%) had coronary bypass grafting. The incidence of death in the mitral, aortic, and double-valve groups was respectively, 15 (6.8%), 12 (7.8%), and 4 (14.3%); and the incidence of prolonged postoperative hospital stay (>14 days) was, respectively, 57 (26.0%), 41 (26.8%), and 8 (28.6%). Only 7 of 147 patients (4.8%) having elective, isolated, first-time valve reoperation died. Multivariable predictors (p < 0.05) of hospital death were age greater than 65 years, male sex, renal insufficiency, and nonelective operation; and predictors of prolonged stay were acute endocarditis, renal insufficiency, any concurrent cardiac operation, and elevated pulmonary artery systolic pressure.

Conclusions. Reoperative bioprosthetic valve replacement can be performed with acceptable mortality and hospital stay. The best results are achieved with elective valve replacement, without concurrent cardiac procedures.     

Systemic atrioventricular conduit for extracardiac bypass of hypoplastic systemic atrioventricular valve

The management of severe congenital mitral stenosis in infants and children is still controversial. We describe our experience with the use of a systemic atrioventricular (SAV) extracardiac conduit to bypass a hypoplastic systemic atrioventricular valve. An SAV extracardiac conduit has been used in six patients (left atrium--left ventricle in five, right atrium--right ventricle in one). One hospital death occurred due to mediastinitis and there were two late deaths, one due to progressive subaortic stenosis and one sudden, possibly due to arrhythmia. Postoperative cardiac catheterization performed in five patients showed reduction of the transmitral gradient from a mean of 16 mmHg to a mean of 5 mmHg. Calcification of the bioprosthetic valve occurred in two patients 3 1/2 years and 2 years respectively after the operation; one died from concomitant subaortic stenosis and one underwent conduit replacement. Although its long-term efficacy is limited, the SAV conduit seems the most reliable surgical option for infants and children with hypoplastic systemic atrioventricular valves unsuited to conventional surgery.     

Current problems in the surgical treatment of acquired heart disease

Two hundred and ninety patients with ischemic heart disease and two hundred and sixty one patients with valvular heart disease have been operated upon in our department. Combined valvular and coronary artery surgery was carried out in 19 cases, coronary artery and peripheral vascular surgery was carried out in 7 cases, and tricuspid valve replacement with SJM was carried out in 20 cases. Early mortality rate of combined valvular and coronary artery surgery was 26%, and late mortality 21%, however, only 3 cases (15.8%) died of LOS. Mortality rate of combined coronary artery and peripheral vascular surgery was 43%, however 1 patient died of LOS. Mortality rate of TVR with SJM was 15% which was rather low in comparison with other valves. A patient who underwent simultaneous surgical treatment of valvular or peripheral vascular disease, and coronary artery disease, ran almost the same risk of LOS as patients without ischemic heart disease. However, myocardial protection was important for these patients because of severe LV dysfunction and myocardial hypertrophy. There is not yet an ideal artificial valve for TVR. At present, SJM is the best available valve in terms of design and hemodynamics.     

微创心脏瓣膜替换术73例报告

目的介绍一种微创心脏瓣膜替换术的新方法。方法于１９９７年３月至１９９８年４月为７３例瓣膜患者经右侧腋下胸部小切口,皮切口平均长度为（８５±０９）ｃｍ,进行了心脏瓣膜替换手术。结果平均循环阻断时间（８８６±３３８）分钟,平均转机（１１７０±４５９）分钟,有５例患者未阻断升主动脉,室颤下完成了二尖瓣替换术。术后气管插管时间（９６±３６）小时,平均胸液引流量（２６４５±１８４３）ｍｌ。１例患者院内死于脑出血。随诊中２例患者出现感染性心内膜炎,其中１例患者死亡。其他随诊良好。结论微创心脏瓣膜替换术安全可靠,可减少手术对患者的影响,利于患者恢复,同时为换瓣手术技术的改进提供了新经验。     

An eight-year experience with porcine bioprosthetic cardiac valves

A total of 589 porcine bioprostheses were implanted in 509 patients from January, 1976, through December, 1983. Of the valves implanted, 390 were Hancock and 199 were Carpentier-Edwards. A total of 1,633 patient-years was accrued, with a mean follow-up of 38 months per patient. Two hundred eight patients had aortic valve replacement, 209 had mitral valve replacement, and 79 had multiple valve replacements, of which 46 were aortic and mitral replacements. The mortality for isolated aortic valve replacement was 5.8%; for isolated mitral replacement, 8.6%, and for all patients, 10.9%. Late mortality was 3.9% per patient-year. The actuarial survival rate at 5 years was 79% for aortic, 68% for mitral, and 76% for aortic-mitral valve replacement. There were 12 thromboembolic events (0.73% per patient-year). Two episodes occurred in patients with an aortic bioprosthesis, nine in patients with a porcine mitral valve, and one in a patient with mitral and tricuspid bioprosthetic valves. The probability of remaining free of thromboembolism at 5 years was 99% for the group having aortic valve replacement, 93% for those having mitral replacement, and 100% for the group having aortic-mitral valve replacements. Thirteen episodes of endocarditis occurred (0.8% per patient-year). Seven of the 13 patients died as a direct result of endocarditis. The probability of remaining free of prosthetic endocarditis at 5 years was 97% for the aortic valve replacement group, 95% for the mitral group, and 97% for the aortic-mitral group. There were 20 instances of xenograft failure (1.2% per patient-year). The probability of remaining free of valve failure at 5 years was 96% for the aortic valve replacement group, 93% for the mitral group, and 93% for the aortic-mitral replacement group. Primary tissue failure of a prosthesis occurred in seven patients, all with Hancock valves (0.43% per patient-year). As yet there has been no primary tissue failure of the Carpentier-Edwards prosthesis. There also appears to be a lower incidence of thromboembolism (Edwards, 0.3% per patient-year; Hancock, 0.8% per patient-year) and endocarditis (Edwards, 0.6% per patient-year; Hancock, 1.0% per patient-year). The low incidence of complications with the porcine bioprosthetic valve, especially the Carpentier-Edwards, encourages us to recommend its continued use, especially in situations in which anticoagulation is contraindicated.     

Mitral valve replacement in the first 5 years of life

Between 1976 and 1986, 19 children aged 1 month to 5 years underwent replacement of the mitral (systemic atrioventricular) valve. Indications for valve replacement included isolated congenital mitral stenosis (n = 2), valve dysfunction associated with a more complex procedure (n = 15), and failed valvuloplasty (n = 2). Seven different valve types were used; nine were mechanical valves and ten were bioprosthetic valves. There were 6 hospital deaths (32%; 70% confidence limits, 20% to 47%). Among the 13 survivors there were 3 late deaths at a mean of 14 months after operation. The late deaths were unrelated to valve malfunction. Thromboembolic events occurred in 2 patients, both with mechanical valves. One minor bleeding complication occurred among 10 patients on a regimen of Coumadin (crystalline warfarin sodium). Five patients, all with bioprostheses, required a second valve replacement. Indications for reoperation included prosthetic valve regurgitation (n = 1) and calcific stenosis (n = 4). No early or late deaths occurred after second valve replacement. Survival was 51% +/- 12% (standard error) at 112 months after valve replacement. Analysis failed to identify age, weight, sex, previous operation, underlying cardiac lesion, or prosthesis size and type as significant risk factors for mortality. Mechanical valves had a lower reoperation rate compared with bioprostheses. These data suggest that although mitral valve replacement within the first 5 years of life is associated with a high operative and late mortality, satisfactory long-term palliation for many patients can be achieved. Mechanical valves are superior to bioprosthetic valves, and offer the best long-term results.     

New approach for replacement of degenerated mitral bioprostheses

OBJECTIVE: The most common indication for reoperation in patients with a mitral bioprosthetic valve is primary tissue failure. Explanation of the bioprosthesis is time-consuming and may be complicated by cardiac rupture at the atrioventricular junction or the posterior left ventricular wall where a strut is imbedded, injury to the circumflex artery and late perivalvular leak. A new approach to avoid these complications by excising only the bioprosthetic tissue and attaching a reversed aortic St. Jude valve to the intact stent has been developed and evaluated. METHODS: We have replaced degenerated mitral bioprostheses with a St. Jude valve in 73 patients during the last 12 years. In 57, including all who had their operation before 1991, explantation was used. The stent was preserved in 16 patients; in the first four we implanted a mitral St. Jude valve (SJM) within the stent, but this only allows a SJM 6-8 mm smaller than the bioprosthesis. We evolved our approach in the last 12 patients to suture a reversed aortic St. Jude valve with extended cuff to the atrial side of the bioprosthetic cuff; this allows the use of a St. Jude valve 2 mm smaller than the bioprosthesis with exact matching of the orifice sizes. The demographic and clinical profiles of the two groups were similar. RESULTS: Operative mortality was 8/57 (14%) in the explantation group and none in the stent-preservation group. Three late perivalvular leaks occurred in the explanation group, and none in the stent-preservation group. Thirteen late deaths occurred in the explanation group, with a 5-year survival rate of 68%, and one late death (cancer) in the stent-preservation group, but the follow-up is significantly shorter. CONCLUSIONS: Leaving the mitral bioprosthetic stent and cuff intact eliminates the need for extensive dissection, thus shortening and simplifying the procedure and diminishing its attendant mortality and morbidity. It offers a safe and logical approach to replacement of a degenerated mitral bioprosthesis with a St. Jude valve of comparable size which projects into the left atrium, rather than a smaller one jammed into the orifice of the bioprosthetic stent.     

Long-term results of porcine bioprosthetic heterograft; a 13-years' experience

One hundred and ninety-four patients underwent valve replacements with the glutaraldehyde-preserved porcine bioprostheses (133 Hancock valves, 39 Angell-Shiley valves, 22 Carpentier-Edwards valves and 3 other valves) from 1974 through 1979. There were 105 women and 89 men, whose age ranged 18 to 62 (mean 38.8) years. One hundred and eighty-two patients had mitral bioprosthetic valve replacement (BVR)s, of which 52 had combined aortic mechanical valve replacements, 8 had aortic BVR's, 3 had tricuspid BVR's and 3 had multi-BVR's. Operative mortality was 10.8%. Only one patient was lost to follow-up. Cumulative duration of follow-up is 1421 patient-years. Linearized rate of anticoagulant related hemorrhage, thromboembolism (TE), prosthetic valve endocarditis (PVE), primary tissue failure (PTF) and valve dysfunction (VD) were 0.07, 1.62, 0.49, 2.74 and 3.66% per patient-year. Actuarial freedom from TE, PVE, PTF and VD were 87.0 +/- 2.7%, 95.6 +/- 1.5%, 65.2 +/- 4.9% and 56.9 +/- 5.6% at 13 years. Actuarial survival rate was 67.4 +/- 4.0% at 13 years. Long term follow-up after valve replacement with porcine bioprosthetic valve confirms low thrombogenicity. But primary tissue failure was the chief cause of valve dysfunction and represent a major problem. At this time, we are going to use porcine bioprosthetic valve in the selected patients, that is in the situations in which anticoagulation is contraindicated.