Medtronic intact porcine bioprosthesis: 10 years' experience

Systematic review of first-in-human and early phase clinical trials for surgically implantable biological mitral valve substitutes

BACKGROUND

The aim of this review was the creation of uniform protocols to carry out and disclose First-In-Human and preliminary clinical trials of biological mitral valve replacement. The need for consistent methodology in these early trials was highlighted by the observation of significant variability in the methods and protocols used across different research.

METHODS

An extensive search through six major databases was carried out to retrieve First-In-Human (FIH) clinical studies evaluating surgically implanted bio-prostheses in the mitral position.

RESULTS

Following the PRISMA guideline, a systematic search identified 2082 published articles until March 2023. After removing duplicates (189), 1862 citations were screened, resulting in 22 eligible studies with 3332 patients for analysis. The mitral valve prostheses in these studies ranged from 21 to 37 mm, with the 29 mm size being most prevalent. Patient numbers varied, with the FIH subgroup including 31 patients and the older subgroup including 163 patients. Average study durations differed: the older subgroup lasted 4.57 years, the FIH subgroup 2.85 years, and the early phase studies spanned 8.05 years on average.

CONCLUSION

FIH clinical report is essential to assess the significance of clinical data required for a "de novo" surgical implant. In addition, understanding the performance of the device, and recognizing the difficulties associated with the innovation constitute important lessons. These insights could be beneficial for the development of bioprosthetic heart valves and formulating a protocol for an FIH clinical trial.

Comparison of radial deformability of stent posts of different aortic bioprostheses

OBJECTIVES

Little is known about the stent deformability required for optimal stented heart valve bioprosthesis design. Therefore, two bioprosthetic valves with known good long-term clinical results were tested. The strain in the radial direction of the stent posts of these valves was compared with contemporary bioprosthetic valves and a native porcine aortic root.

METHODS

Medtronic Intact and Carpentier-Edwards Standard (CES), and four contemporary bioprostheses, including one self-expanding prosthesis, were tested with three sonomicrometry probes per valve fixed at commissure attachment points. The mean values from 2400 data points from three measurements of the interprobe distances were used to calculate the radius of the circle circumscribed around the three probes. Changes in the radius of the aortic root at pressures 70-90 and 120-140 mmHg (pressure during diastole and systole) and that of the stent posts at 70-90 and 0-10 mmHg (transvalvular pressure gradient during diastole and systole) were compared.

RESULTS

An increase in radius by 7.3 ± 2.6, 8.7 ± 0.0 and 3.9 ± 0.0% for the porcine aortic root, CES and Intact valves, respectively, was observed during transition from diastolic to systolic pressure and less for contemporary bioprostheses-mean 2.5 ± 0.9%, lowest 1.2 ± 0.0.

CONCLUSIONS

The results indicate that the radial deformability of bioprosthetic valve stent posts can be as low as 1.2% for xenoaortic and 3.0% for xenopericardial prostheses with no compromise of valve durability. Although these results suggest that valve stent post-deformability might not be of critical importance, a concrete answer to the question of the significance of stent deformability for valve durability can be obtained only by acquiring long-term follow-up results for valve prostheses with rigid stents.

Antithrombotic therapy following bioprosthetic aortic valve replacement

The life expectancy of the general population is increasing. This has meant that more elderly patients are requiring aortic valve replacement (AVR). The choice of valve replacement and its durability are important. Bioprosthetic (tissue) heart valves were introduced into clinical use in the 1960s and were developed primarily to reduce the complications associated with thromboembolism (TE) and the need for lifelong oral anticoagulation, due to their low thrombogenicity compared to mechanical prostheses. This makes them suitable for use in elderly patients (aged>65 years) and in others where the risks of anticoagulation are higher or anticoagulation is contraindicated. There is thought to be a higher risk of TE for up to 90 days following bioprosthetic AVR. Guidelines for the management of patients with valvular heart disease published by the American College of Cardiology (ACC)/American Heart Association (AHA), the American College of Chest Physicians (ACCP) and the European Society of Cardiology (ESC) all recommend the use of an anticoagulation regimen for the first 3 months following bioprosthetic AVR. However, there is division of opinion and practice, despite these recommendations, and more recent studies have not supported the evidence for these guidelines. In this article, we review the literature on the use of anticoagulation in the first 90 days following bioprosthetic AVR.

Anticoagulation or antiplatelet therapy of bioprosthetic heart valves recipients: an unresolved issue

Improvements in the performance and longevity of biological valve prostheses have steadily increased their rates of implantation in recent years. Aortic bioprostheses, which are commonly used in the elderly or when the risks of anticoagulating are high, have generally been associated with low rates of long-term complications. Freedom from anticoagulation, therefore, represents the main theoretical advantage of biological, compared with mechanical, aortic prostheses. While a variety of anticoagulant and antiplatelet drug regimens have been described, a precise antithrombotic protocol for the early postoperative period after bioprosthetic aortic valve replacement has not been developed. There are also important differences between the international guidelines published. This review examines the clinical evidence concerning the use of vitamin K antagonist and antiplatelet therapy in the early management of the antithrombotic complications after bioprosthetic aortic valve replacement.

Commissural dehiscence: A rare and peculiar cause of porcine valve structural deterioration

OBJECTIVE

Calcification is the main cause of structural valve deterioration; however, other causes of failure have been identified, and among them, dehiscence of a commissure from the stent has been reported in several models of porcine valves. The aim of this study was to analyze the rate and mode of occurrence of this complication in first- and second-generation porcine bioprosthetic explants.

METHODS

Among 586 porcine xenografts explanted and analyzed at the Institute of Pathological Anatomy of the University of Padua, 17 (2.9%) have been replaced for incompetence because of commissural dehiscence. All these explants were in the mitral position, with the exception of a Carpentier-Edwards supra-annular aortic valve prosthesis.

RESULTS

Dehiscence was observed in 9 (1.9%) of 455 Hancock standard explants, in 1 (3.2%) of 31 Hancock II, in 3 (8.6%, 2 standard and 1 supra-annular) of 35 Carpentier-Edwards, in 1 (2.4%) of 42 Bioimplants, and in 3 (50%) of 6 Xenotech after a mean time function of 157 +/- 50, 156, 96 +/- 29, 143, and 130 +/- 8 months, respectively. Dehiscence was the sole cause of incompetence in 6 cases. An impending commissural dehiscence caused by blood creeping was observed in one case. This might be an explanation for the dehiscence other than excessive trimming of the aortic wall.

CONCLUSIONS

Commissural dehiscence is an uncommon and peculiar mode of failure of porcine valves implanted in the mitral position and was observed earlier and more frequently with Carpentier-Edwards porcine explants (P < .05). We speculate that pericardial strip protection of the suture between the Dacron fabric and porcine aortic wall, as used in the Biocor porcine valve, might prevent this complication.

Intermediate results of isolated mitral valve replacement with a Biocor porcine valve

BACKGROUND

We analyzed the intermediate experience, survival, and prosthetic complications of patients who received the Biocor valve, a new-generation porcine valve, in the mitral position.

METHODS

At the University of Padua, between May 1992 and January 2004, 154 consecutive patients (102 female and 52 male patients; mean age, 72.3 +/- 6 years; age range, 37-86 years) received 158 mitral Biocor prostheses (Biocor Industria e Pesguisa Ltda, Belo Horizonte, Brazil). Thirty-five percent of the patients had previous mitral operations, 24% had coronary artery bypass grafting, and 34.6% had other procedures. Median preoperative New York Heart Association class was III. Echocardiography was performed in 75% of the long-term survivors. Follow-up included 609.4 patient-years and was 100% complete, with a median time of 4 patient-years (range, 0.02-11.3 years). At 8 years, 20 (14%) of 142 operative survivors were still at risk.

RESULTS

Early mortality was 13.6%. According to univariate analysis, New York Heart Association class III to IV, ejection fraction of less than 40%, urgency, male sex, and coronary artery bypass grafting were significant perioperative risk factors. Eight- and 10-year actuarial survival was 51.1% +/- 5.6% (40 deaths). Eight-year actuarial freedom from valve-related death, thromboembolism, anticoagulant-related hemorrhage, endocarditis, paravalvular leak, and valve-related complications were 85.2% +/- 5%, 85.7% +/- 4.4%, 92.6% +/- 3.7%, 94.1% +/- 3%, 91.8% +/- 3%, and 70.2% +/- 5.7%, respectively. Freedom from structural valve deterioration was 100%. Actual freedom from reoperation was 93.2% +/- 2.2%. By Doppler echocardiography, the peak and mean transprosthetic gradients were 15 +/- 5 mm Hg and 6.3 +/- 3 mm Hg, respectively (mean follow-up, 4.2 +/- 2.7 years).

CONCLUSION

At intermediate follow-up, the Biocor prosthesis in the mitral position showed excellent results in terms of valve durability when compared with other second-generation tissue valves.

Antithrombotic Therapy in Valvular Heart Disease—Native and Prosthetic

This chapter about antithrombotic therapy in native and prosthetic valvular heart disease is part of the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following: For patients with rheumatic mitral valve disease and atrial fibrillation (AF), or a history of previous systemic embolism, we recommend long-term oral anticoagulant (OAC) therapy (target international normalized ratio [INR], 2.5; range, 2.0 to 3.0) [Grade 1C+]. For patients with rheumatic mitral valve disease with AF or a history of systemic embolism who suffer systemic embolism while receiving OACs at a therapeutic INR, we recommend adding aspirin, 75 to 100 mg/d (Grade 1C). For those patients unable to take aspirin, we recommend adding dipyridamole, 400 mg/d, or clopidogrel (Grade 1C). In people with mitral valve prolapse (MVP) without history of systemic embolism, unexplained transient ischemic attacks (TIAs), or AF, we recommended against any antithrombotic therapy (Grade 1C). In patients with MVP and documented but unexplained TIAs, we recommend long-term aspirin therapy, 50 to 162 mg/d (Grade 1A). For all patients with mechanical prosthetic heart valves, we recommend vitamin K antagonists (Grade 1C+). For patients with a St. Jude Medical (St. Paul, MN) bileaflet valve in the aortic position, we recommend a target INR of 2.5 (range, 2.0 to 3.0) [Grade 1A]. For patients with tilting disk valves and bileaflet mechanical valves in the mitral position, we recommend a target INR of 3.0 (range, 2.5 to 3.5) [Grade 1C+]. For patients with caged ball or caged disk valves, we suggest a target INR of 3.0 (range, 2.5 to 3.5) in combination with aspirin, 75 to 100 mg/d (Grade 2A). For patients with bioprosthetic valves, we recommend vitamin K antagonists with a target INR of 2.5 (range, 2.0 to 3.0) for the first 3 months after valve insertion in the mitral position (Grade 1C+) and in the aortic position (Grade 2C). For patients with bioprosthetic valves who are in sinus rhythm and do not have AF, we recommend long-term (> 3 months) therapy with aspirin, 75 to 100 mg/d (Grade 1C+).

The Medtronic Intact Bioprosthesis: Clinical and Hemodynamic Performance Over 13 Years

We evaluated our results over 13 years with the aortic-position Medtronic Intact bioprosthesis. Our study involved 91 consecutive patients with isolated aortic valve replacement with the Medtronic Intact bioprosthesis. The follow-up was complete for 95%. Mean follow-up was 6.61 years (range 16 days-13 years), 590 patient years. Early mortality rate was 3.3%. Late mortality was 23 patients. Survival at 13 years was 53.52% (SD = 7.63%). The linearized rate of major thromboembolism was 0.34% per patient year; rate of major bleeding events was 0.33% per patient year. The rate of nonstructural dysfunction was 0.16% per patient year. Rate of reoperation was 0.53% and rate of structural valve deterioration was 0.16% per patient year. New York Heart Association (NYHA) postoperative classes were I to II in 92.21%. Gradients were as follows: 21 to 23.87 mm Hg, 23 to 18 mm Hg, 25 to 15.5 mm Hg, and 27 to 16.50 mm Hg. Structural valve deterioration was low during the 13 years of follow-up. Valve gradients and areas remained the same over the follow-up period. The Medtronic Intact bioprosthesis shows excellent clinical and hemodynamic performance at 13 years of follow up.

Medtronic Intact porcine bioprosthesis experience to twelve years

BACKGROUND

The Medtronic Intact porcine bioprosthesis was further evaluated to determine the influence of zero-pressure glutaraldehyde fixation on structural valve deterioration (SVD).

METHODS

From 1986 through 1996, at three Canadian centers, 1,272 patients had 1,296 procedures: 836 aortic valve replacement (AVR), 332 mitral valve replacement (MVR), 14 tricuspid valve replacement, 3 pulmonary valve replacement, and 111 multiple valve replacements. The mean age of the patient population was 67 years (range 9 to 91 years). The total follow-up was 8,011 patient-years (mean 6.2 years).

RESULTS

The late mortality (overall) was 4.8% and 6.7% per patient-year for AVR with or without concomitant procedures, respectively; and 4.7% and 10.4% per patient-year for MVR, respectively. There were 51 cases of SVD (AVR 22 of 836; MVR 23 of 332; pulmonary valve replacement 1 of 3; and multiple valve replacement 5 of 111). The actuarial freedom from SVD at 12 years for AVR was 94.3%+/-3.3% for patients aged 61 to 70 years and 97.7%+/-1.1% for those more than 70 years; for MVR actuarial freedom from SVD at 12 years was 93.7%+/-3.9% for patients more than 70 years. The actual freedom at 12 years from SVD for AVR was 92.4%+/-3.1% for patients aged 51 to 60 years, 96.1%+/-2.1% for those 61 to 70 years, and 98.4%+/-0.7% for those older than 70 years; for MVR actual freedom from SVD at 12 years was 89.6%+/-3.2% for patients 61 to 70 years and 96.6%+/-3.4% for those more than 70 years.

CONCLUSIONS

The Medtronic Intact porcine bioprosthesis, formulated with tissue preservation at zero-pressure fixation, has encouraging freedom from structural failure.

Fifteen-year clinical experience with the biocor porcine bioprostheses in the mitral position

BACKGROUND

Bioprosthetic valve use represents a crucial improvement in surgical treatment of mitral valve disease. The aim of this study is to determine the long-term durability of the Biocor porcine bioprosthetic mitral valve.

METHODS

Between 1985 and 1989, a total of 158 Biocor porcine bioprosthetic valves were placed in the mitral position, and long-term results of these patients were investigated retrospectively in 1999.

RESULTS

Thirty-day mortality was 4.4% (7 patients). Total follow-up was 1,499 patient-years. Actuarial survival was 83.66% +/- 3% at 5 years, 77.78% +/- 3.36% at 13 years (1.8% patient-year). Multivariate analysis demonstrated younger age, duration of implantation, congestive heart failure, and functional class to be significant predictors of late mortality. Actuarial freedom from valve-related mortality was 98.58% +/- 1% at 15 years (0.13% patient-year). Actuarial freedom from structural valve deterioration was 95.49% +/- 1.8% at 5 years, 70.2% +/- 4.12% at 10 years, and 64.82% +/- 5.34% at 13 years (2.6% patient-year). Actuarial freedom from structural valve deterioration-related reoperation was 98.43% +/- 1.1% at 5 years, 89.15% +/- 2.85% at 10 years, and 76.82% +/- 7.91% at 14 years. Multivariate analysis showed younger age and duration of implantation to be significant predictors of structural valve deterioration and its related reoperation.

CONCLUSIONS

By studying a 15-year time period, it is seen that this new generation porcine bioprosthetic valve should be considered an alternative for mechanical valves in selected patients.

Antithrombotic therapy in valvular heart disease

Whether antithrombotic therapy in elderly patients differs from that in younger populations depends on whether the risk for such bleeding differs in the elderly. Regarding long-term therapy with warfarin derivatives, evidence shows that there is a difference. The anticoagulation response to warfarin is exaggerated with advancing age. This article discusses antithrombotic therapies for valvular heart disease, including bioprosthetic and mechanical prosthetic heart valves, aspirin and dipyridamole in combination with oral anticoagulant therapy, antiplatelet agents alone or in combination with very low dose warfarin, tilting disk valves, valve position, first-generation valves compared with modern valves, interruption of anticoagulant therapy, and miscellaneous indications for antithrombotic therapy.

Antithrombotic therapy in patients with mechanical and biological prosthetic heart valves

1. Permanent therapy with oral anticoagulants offers the most consistent protection in patients with mechanical heart valves. 2. Antiplatelet agents alone do not consistently protect patients with mechanical prosthetic heart valves, including patients in sinus rhythm with St. Jude Medical valves in the aortic position. 3. Levels of oral anticoagulants that prolong the INR to 2.0 to 3.0 appear satisfactory for patients with St. Jude Medical bileaflet and Medtronic-Hall tilting disk mechanical valves in the aortic position, provided they are in sinus rhythm and the left atrium is not enlarged. Presumably, this is also true for the CarboMedics bileaflet valve, based on the observation of no clinically important difference in the rate of systemic embolism with this valve and the St. Jude Medical bileaflet valve. 4. Levels of oral anticoagulants that prolong the INR to 2.5 to 3.5 are satisfactory for tilting disk valves and bileaflet prosthetic valves in the mitral position. 5. Experience in patients with caged ball valves who had prothrombin time ratios reported in terms of the INR is sparse, because few such valves have been inserted in recent years. The number of surviving patients with caged ball valves continues to decrease. It has been suggested that the most advantageous level of the INR in patients with caged ball or caged disk valves should be as high as 4.0 to 4.9. However, others have shown a high rate of major hemorrhage with an INR that is even somewhat lower, 3.0-4.5. The problem is self-limited, however, because few such valves are being inserted. 6. In patients with mechanical heart valves, aspirin, in addition to oral anticoagulants, has been shown to diminish the frequency of thromboemboli. The risk of bleeding is somewhat increased if the INR is 2.0 to 3.0 or 2.5 to 3.5. However, if the INR is 3.0 to 4.5, the risk of bleeding becomes excessive with aspirin. There are no investigations in which aspirin 80 mg/d in combination with oral anticoagulants was evaluated. 7. Data are insufficient to recommend dipyridamole over low doses of aspirin in combination with warfarin. Whether dipyridamole plus aspirin is more effective than aspirin alone when used with warfarin is undetermined. 8. Patients with bioprosthetic valves in the mitral position as well as patients with bioprosthetic valves in the aortic position may be at risk for thromboemboli during the first 3 months after operation. 9. Among patients with bioprosthetic valves in the mitral position, oral anticoagulants at an INR of 2.0 to 2.3 were as effective as an INR of 2.5 to 4.0 and were associated with fewer bleeding complications during the first 3 months after operation.10. Aspirin may reduce the long-term frequency of thromboembolism in patients with bioprosthetic valves.

The stentless xenograft aortic valve: The wheel turns around

BACKGROUND

A brief overview of the historical pathways of both stented and stentless porcine xenografts is presented in order to understand the return to and continuing clinical use of stentless devices. In addition, 7-11 years of durability with various models of stentless porcine valves has now accumulated and is beginning to be of relevance in determining the future place of this xenograft. Stentlessness and anticalcium agents, coupled with the poor results of stented xenografts in certain patient groups, have led to a resurgence of the clinical use of stentless xenograft valves for aortic valve replacement. An overview of the present state and future of stentless valves is given.

METHODS

At both The Prince Charles Hospital and St Andrew's War Memorial Hospital, Queensland, Australia, 307 patients have received the Model 300 CryoLife-O'Brien stentless composite aortic xenograft from December 1992 to February 2000. Associated procedures were required in 56% of patients (mostly coronary artery bypass, mean 2.4 grafts, in 144 patients (47%) and left ventricular myomectomy in 34 patients (11%)).

RESULTS

The hospital mortality (four early deaths) has been 1.3 +/- 1% (CL 95%) and the follow-up 100% for this analysis. The mean patient age was 73 years (range 57-89 years with 16% being 80 years and over). Morbid events have included six perivalvar leaks: four trivial and identified only on echo Doppler (no clinical murmurs) and two patients requiring reoperation at 10 days and 12 weeks with simple successful repair verified on subsequent echocardiograms. Of the 307 patients over the 7 year period, three valves only have been explanted, two for endocarditis at 1.5 and 3.5 years and one for possible technically induced structural failure at 15 months (probable needle damage). With this exception, there has been as yet no other intrinsic leaflet failure. Four early thromboembolic events (4 days-5 weeks) in patients with atrial fibrillation (no anticoagulants used postoperatively with the first 80 patients) constituted the important early morbid events. Late mortality of this elderly patient cohort has occurred in 27 patients over 7 years of maximum follow-up. One death (endocarditis) has been valve related at 5 years. Serial echocardiography (some 700 echoes in the study of this valve) has demonstrated a mean gradient of 7-9 mmHg with a very low incidence of trivial incompetence (96%) on Doppler examination with implant valve sizes ranging from 21 to 29 mm. One patient had significant regurgitation requiring reoperation. There has been no progression of either incompetence or stenosis of the remaining patients in this follow-up, now into the eighth postoperative year.

CONCLUSION

The early and intermediate results appear excellent in this elderly patient cohort. Nevertheless, important surveillance is obviously required to determine the durability at 10-12 years, a crucial time when stented porcine xenografts began to show an obvious failure rate from structural deterioration, in the middle and elderly aged patient cohort. An attempt is made to outline the future of this type of stentless xenograft and to justify that its cautious use should probably be extended down to the over 50 year age patient cohort.

Carpentier-Edwards standard and supraannular porcine bioprostheses: comparison of technology

BACKGROUND

Performance with regard to structural valve deterioration (SVD) with the Carpentier-Edwards standard (CE-S) and supraannular (CE-SAV) (Baxter Healthcare Corp, Irvine, CA) porcine bioprostheses was evaluated to determine whether progress in reduction of structural failure has been achieved with technological changes.

METHODS

The CE-S was implanted during 567 aortic valve replacement (AVR) and 486 mitral valve replacement (MVR) procedures, and the CE-SAV was implanted during 1,670 AVR and 1,096 MVR procedures. The failure mode of early stent dehiscence with the CE-SAV prosthesis, thought to be controlled by manufacturing changes in 1986 and 1987, supported comparison of the CE-SAV with censored cases of stent dehiscence. Stent dehiscence accounted for only 1.2% (1 of 81) and 14.1% (29 of 205) of AVR and MVR CE-SAV failures, respectively.

RESULTS

The only difference for AVR for freedom from SVD occurred in the 21- to 40-year age group at 15 years and was 68% for the CE-SAV and 31% for the CE-S (p<0.05). In the 61- to 70-year age group, freedom from SVD at 15 years was 76% for the CE-S and 84% for the CE-SAV; for the 71-year or higher age group, freedom from SVD was 89% and 95%, respectively (p = NS). For MVR freedom from SVD was different only in the 71-year or higher age group and was 90% for the CE-S and 59% for the CE-SAV (p<0.05). Freedom from SVD was reduced but was similar (p = NS) for the other age groups. For AVR the actual freedom from SVD at 15 years for the CE-S and CE-SAV was, respectively, 79% and 72% for the 51- to 60-year age group, 86% and 91% for the 61- to 70-year age group, and 98% and 98% for the 71-year or higher age group. For MVR, these rates were, respectively, 69% and 75% for the 61- to 70-year age group and 96% and 89% for the 71-year and higher age group.

CONCLUSIONS

The technologic advancements made in the second-generation CE-SAV bioprosthesis to reduce the incidence of structural failure have not uniformly been successful. The actual freedom from SVD provides evidence for implantation of porcine bioprostheses for AVR in age groups 61 to 70 years and 71 years or higher and for MVR in the age group 71 years or higher.

The medtronic intact porcine valve: ten-year clinical review

OBJECTIVE

Our objective was to assess the long-term mortality and morbidity associated with the Medtronic Intact valve (Medtronic, Inc, Minneapolis, Minn).

METHOD

Between 1983 and 1996, 447 patients (280 men and 167 women) received 466 Intact valves: 280 aortic, 156 mitral, and 30 tricuspid. The mean age was 57 years (median 63 years), with 45% younger than 60 years. The mean New York Heart Association class was 3.1. The follow-up was 98% complete and extended for 39 months (1-154 months) and 1324 patient-years. There were 32 valves at risk at 10 years after implantation. Doppler echocardiography was performed whenever possible in patients followed up for longer than 4 years (mean 8 years) after implantation.

RESULTS

Ten-year overall actuarial survival was 30% +/- 6% (14% +/- 7% for New York Heart Association classes IV-V and 39% +/- 8% for classes I-III). At 10 years freedom from infective endocarditis was 92% +/- 3%, freedom from thromboembolism was 80% +/- 5%, and freedom from nonstructural valve deterioration was 95% +/- 2%. Ten-year freedom from explantation was 64% +/- 6%, freedom from valve-related events was 51% +/- 6%, and freedom from valve-related death was 88% +/- 3%. There were 26 examples of structural valve deterioration, mainly caused by leaflet calcification (in 17 cases) and by buttress detachment (in 6 cases). In the aortic position at 10 years freedom from structural valve deterioration was 81% +/- 9%, but with only 1 event in patients older than 40 years (freedom 92% +/- 8%) and 100% freedom in patients older than 60 years. There was also 100% freedom from structural valve deterioration in the tricuspid position. In the mitral position freedom was 65% +/- 8%, with no significant difference between age groups.

CONCLUSION

The Intact valve provides superior results in the aortic position in patients older than 40 years and in the tricuspid position at all ages.