HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Cary W. Akins Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Akins, C. W. Search for Related Content PubMed PubMed Citation Articles by Akins, C. W.

Ann Thorac Surg 1995;60:1836-1844
© 1995 The Society of Thoracic Surgeons

---

Current Review

Results With Mechanical Cardiac Valvular Prostheses

Cardiac Surgical Unit, Massachusetts General Hospital, Boston, Massachusetts

	Abstract

Top Footnotes Abstract Introduction The Study Valves Functional Mechanical... Review of Long-Term... Composite Thromboembolism and... Comment References

 
Mechanical cardiac valvular prostheses continue to be more popular than bioprostheses for heart valve replacement operations. Five different brands of mechanical heart valves are now approved for implantation in the United States: Starr-Edwards models 1260 and 6120, Medtronic-Hall, St. Jude Medical, Omniscience, and CarboMedics. Each model of mechanical valve has certain positive and negative attributes, but none is functionally mechanically perfect. A review of the published long-term results with these valves favors the Medtronic-Hall and St. Jude Medical valves. A new method of assessing the thrombogenic potential and requirement for anticoagulation of the different mechanical valves, namely the composite thromboembolism and bleeding index, is proposed. Evaluation of the new index demonstrates a modest advantage for the Medtronic-Hall valve, particularly in the aortic position.

	Introduction

Top Footnotes Abstract Introduction The Study Valves Functional Mechanical... Review of Long-Term... Composite Thromboembolism and... Comment References

 
Despite the increased aging of the valve replacement population in the United States and a trend toward insertion of more bioprostheses in these patients, mechanical heart valves continue to predominate over bioprostheses in the United States with an approximate 65% to 35% market share advantage. Although the division of the valve market between mechanical and tissue valves varies widely among countries (for example, mechanical valves constitute approximately 90% of the market in Japan but only 10% of the market in Brazil), mechanical valves make up about 60% of the heart valves implanted worldwide.

A report in 1991 reviewed the previous 15 years' experience from the English-language literature for the four mechanical cardiac valvular prostheses then approved by the Food and Drug Administration (FDA) for implantation in the United States [1]. Since that review, one more mechanical valve, the CarboMedics bileaflet prosthesis, was approved for market release by the FDA in 1993.

This review updates the reported experience with the five mechanical valves currently approved by the FDA. The review is divided into three parts: first, an assessment of the functional mechanical characteristics of the prostheses; second, a review of the published complications; and third, a suggestion for an index that views in a new way the primary problem with mechanical valves, their inherent thrombogenicity, and requirement for anticoagulation.

	The Study Valves

Top Footnotes Abstract Introduction The Study Valves Functional Mechanical... Review of Long-Term... Composite Thromboembolism and... Comment References

 
Table 1 lists the five mechanical cardiac valvular prostheses currently approved by the FDA for implantation in the United States, their dates of introduction, the estimated number of each prosthesis inserted according to the individual manufacturer, and their current list prices in the United States. Photographs and a full description of the design characteristics of the Starr-Edwards models 1260 and 6120, Medtronic-Hall, St. Jude Medical, and Omniscience prostheses can be found in the review from 1991 [1].

View larger version (133K): [in this window] [in a new window]   Fig 1. . CarboMedics cardiac valvular prosthesis.

	Functional Mechanical Characteristics

Top Footnotes Abstract Introduction The Study Valves Functional Mechanical... Review of Long-Term... Composite Thromboembolism and... Comment References

The lowest profile is presented by the CarboMedics valve, followed closely by the St. Jude Medical prosthesis, whose pivot guards make it somewhat taller. Although the two single-disc valves have a low profile in the closed position, they do have a higher profile in the open position than do the bileaflet designs. The caged-ball design of the Starr-Edwards valves gives them the highest profile.

Rotatability is not of any consequence for the Starr-Edwards caged-ball design. Of the four disc valves, only the St. Jude Medical prosthesis cannot be rotated within its sewing ring, which could be disadvantageous in some circumstances. A rotatable version of that prosthesis is reportedly being currently tested.

Freedom from occluder impingement is poorest for the Medtronic-Hall valve, because the occluder seats horizontally at the equator of the housing and thus can be immobilized by retained valve remnants or sutures that are left too long. Complete closure of the Omniscience single disc and the discs of the two bileaflet valves can be hindered by subvalve structures, sutures, or native valve tissue as well, but the leaflets are uncommonly totally immobilized. Like the single disc of the Omniscience valve, the discs of the CarboMedics valve seat closer to the edge of the housing and are, therefore, not as protected as those of the St. Jude Medical valve. Impingement of the ball of a Starr-Edwards valve, although uncommon, can occur if sutures or valve fragments fall across the metal housing and keep the ball from completely seating.

The St. Jude Medical and Medtronic-Hall valves have acceptably low and essentially equal transvalve gradients, even in small sizes. The gradient across a CarboMedics valve is minimally higher, probably due to the fact that the leaflets are designed not to open quite as far as those of the St. Jude Medical valve. In smaller sizes the Starr-Edwards valves have almost unacceptable gradients, and the Omniscience has gradient relief characteristics that place it between the Starr-Edwards valves and the other disc prostheses.

Complete opening of a mechanical valve can be viewed in two ways: first, the completeness of rotation or translation of the occluder from the closed to the open position; and second, the length of time that the occluder stays open during that portion of the cardiac cycle when it is intended to be open. Complete opening of the single disc of the Medtronic-Hall valve is virtually always achieved both in terms of rotation and translation and also in terms of maintenance of the open position. In the aortic position both discs of the St. Jude Medical and the CarboMedics valves rotate to the open position uniformly and remain open during systole. However, one could argue that a perfect complete opening score is not justified for these two bileaflet valves because increasing evidence suggests that in the mitral position, when a bileaflet valve is implanted in the anatomic orientation, an important percent of those valves will demonstrate biphasic partial closure of both leaflets during diastole (``diastolic fluttering'') in patients with atrial fibrillation [2, 3]. In an important number of cases the disc of the Omniscience valve does not rotate to the open position completely [4, 5]. Although complete opening of the ball in a Starr-Edwards valve is the norm, ball rebound off the distal cage can affect the secondary orifice of the caged-ball design, and also the inertia of the ball may keep it from completely opening or closing at high heart rates.

Dynamic regurgitant fraction, that part of valvular regurgitation that occurs before the occluder becomes seated in the housing, is lowest in the single-disc prostheses, the Medtronic-Hall and Omniscience, followed closely by the bileaflet designs, the St. Jude Medical and CarboMedics. The minimally lower score for the bileaflet valves relates to the reported clinical frequency of asynchronous closure of the two discs in bileaflet valves [2, 3]. The inertia of a Starr-Edwards ball delays its closure.

Static leak rate, that part of valvular regurgitation that occurs once the occluder is seated, is essentially nonexistent for the Starr-Edwards valves. The Medtronic-Hall and Omniscience valves have a moderate built-in leak rate to flush the disc and housing. The increased length of the lines of closure between the discs and the housing in conjunction with the tolerances needed to fulfill the engineered requirements for washing the valve components give the St. Jude Medical and CarboMedics valves somewhat higher static leak rates.

Thus, each prosthetic design has some very strong mechanical advantages but also some important limitations.

	Review of Long-Term Complications

Top Footnotes Abstract Introduction The Study Valves Functional Mechanical... Review of Long-Term... Composite Thromboembolism and... Comment References

 
To the reports used to prepare the previous review on this topic have been added those studies published through January 1995. The reports chosen had to use relatively standard definitions of valve-related complications [6], provide separate results for aortic and mitral prostheses, and contain enough information that the actual number of adverse events and the corresponding patient-years of follow-up could be accurately measured or closely approximated. As with the previous review, the statistical methods used in the available literature impose the use of linearized rates of complications; I acknowledge the limitations of that method.

There have been no new reports on the Starr-Edwards valves. New sources of data were available for the Medtronic-Hall [7–11 and my unpublished data], St. Jude Medical [12–20], and Omniscience valves [21].

Data on the CarboMedics valve came from one large cumulative experience [22]. However, that multiinstitutional series reports only the linearized rates for ``late'' events. The author's contention was that because the FDA currently requires linearized rates for only those complications that occur more than 30 days after implantation and does not count any events that occur if the patient is never discharged postoperatively, reporting only ``late'' events is appropriate. Obviously the hazard function for most complications is highest in the early period after mechanical valve implantation and for prostheses with shorter periods of follow-up, ``early'' events will have a proportionally greater impact on the calculated linearized rates of complications. However, most reports about other prostheses include the ``early'' events, as suggested by the guidelines, and, therefore, the ``early'' events for the CarboMedics valve, which can be found in their company's published clinical update [23], have been included.

The combined study populations for each type of prosthesis and the cumulative patient-years of follow-up are recorded in Table 3. The percentages in Table 3 demonstrate that we continue to have good long-term information on only a small sample of each valve type.

Aortic Valves
Nonstructural dysfunction, which comprises largely paravalvular leak and to a lesser extent hemolysis, is lowest in the aortic position (Table 4) for the Starr-Edwards valve, followed closely by the Medtronic-Hall and St. Jude Medical valves. It is a little higher for the CarboMedics valve and further elevated for the Omniscience valve.

	Composite Thromboembolism and Bleeding Index

Top Footnotes Abstract Introduction The Study Valves Functional Mechanical... Review of Long-Term... Composite Thromboembolism and... Comment References

View larger version (29K): [in this window] [in a new window]   Fig 2. . Relationship of level of anticoagulation to the incidences of thrombosis, thromboembolism, and bleeding for a hypothetical patient with a mechanical heart valve. X marks the ideal point of no thrombosis and the fewest thromboembolic events for the lowest level of anticoagulant-related bleeding.

Thus, I have generated a new measure of mechanical valve thrombogenicity, the ``composite thromboembolism and bleeding index,'' by selecting only those reports that provided accurate data for both thromboembolism and anticoagulant-related bleeding. The composite linearized rate in this index is calculated by adding together all thromboembolic and bleeding events from those reports that provide both numbers and dividing by the cumulative patient-years of follow-up from those reports. Studies that report data for only one of the complications are excluded. Further, in keeping with the previous design, the results for aortic and mitral valves have been separated.

The composite thromboembolism and bleeding indices for aortic prostheses are recorded in Table 16, along with the total number of patients and patient-years of follow-up available to generate that number for each model of valve. The lowest composite index for aortic valves is reported for the Omniscience valve, but this number is generated from data available for only 81 patients and 139 patient-years of follow-up. For the other valves for which there is much better follow-up, the lowest index is reported for the Medtronic-Hall valve at 2.77% per patient-year. The rate for the Starr-Edwards valve is considerably higher, followed by almost identical rates for the bileaflet CarboMedics and St. Jude Medical valves.

	Comment

Top Footnotes Abstract Introduction The Study Valves Functional Mechanical... Review of Long-Term... Composite Thromboembolism and... Comment References

 
The findings in this review are generally similar to those reported in 1991. Although the Starr-Edwards models 1260 and 6120 valves have demonstrated noteworthy durability, their poorer gradient relief and somewhat elevated incidence of valve-related complications make them not truly competitive with current disc prostheses. Results reported with the Omniscience valve, although widely disparate, do not favor its hemodynamic performance or its freedom from complications.

The St. Jude Medical and, to a lesser extent, the Medtronic-Hall valves continue to be the most popular mechanical prostheses in the United States because of their clinically documented excellent and comparable hemodynamic performance in addition to their acceptably low rates of valve-related complications. If there are any differences between the long-term performance of these two prostheses, it may be that the Medtronic-Hall valve may have a modest advantage in terms of diminished thrombogenicity, whereas the St. Jude Medical valve has a lower reported rate of reoperation. The major potential drawback of the St. Jude Medical valve remains its reported loss of structural integrity in occasional patients, albeit a very low percentage, whereas the primary shortcoming of the Medtronic-Hall valve is still the attention required of the surgeon at the time of insertion to avoid occluder impingement.

Finally the CarboMedics valve, the new addition to the list, probably fits into the ranking just behind the Medtronic-Hall and St. Jude Medical valves on the basis of somewhat higher transvalve gradients and increased incidence of thromboembolism despite adequate anticoagulation, especially in the mitral position. Longer follow-up will be necessary to accurately determine whether the CarboMedics valve or the Omniscience valve will become truly competitive with the Medtronic-Hall and St. Jude Medical valves.

This report does not provide any determinations of statistical significance comparing the results with different prostheses. Any retrospective, cumulative study such as this is potentially subject to major problems with statistical reliability. The numbers generated for the reported complications for each prosthesis are clearly dependent on the validity of the individual studies, which were often performed according to different protocols. In addition the characteristics of the different patient populations that constitute the various study groups are obviously widely disparate. I have, therefore, never felt comfortable applying univariate statistical methods to this multivariate problem, namely, comparing the differences between observed results with different prostheses from differing populations, collected by various methods.

One particular difficulty uncovered in this review warrants some emphasis and demonstrates how results with the same valve used in different institutions can produce conflicting results. Recent reports of results with the St. Jude Medical valve from Japan and Germany, two highly developed countries with well-organized health care systems, are examples of this apparent anomaly.

Beginning with St. Jude Medical aortic prostheses, Aoyagi and colleagues [18] in Kurume, Japan, report the linearized rates for thromboembolism, anticoagulant-related bleeding, and the composite thromboembolism and bleeding index to be 1.0%, 0.4%, and 1.3% per patient-year, respectively. Similarly, Nakano and associates [17] from Tokyo, Japan, report the linearized rates for thromboembolism, anticoagulant-related bleeding, and the composite thromboembolism and bleeding index for aortic valves to be 1.4%, 0.1%, and 1.5% per patient-year, respectively. In contrast Horstkotte and co-workers [16] from Dusseldorf, Germany, report for their aortic prostheses the linearized rates of thromboembolism, anticoagulant-related bleeding, and the composite thromboembolism and bleeding index to be 2.7%, 4.1%, and 6.8% per patient-year, respectively. In addition the German data do not contain events that occurred within the first 3 months after valve implantation, nor do they contain more than the first event for patients who suffered multiple events!

For St. Jude Medical mitral valves Aoyagi and colleagues [18] report the linearized rates of thromboembolism, anticoagulant-related bleeding, and the composite thromboembolism and bleeding index to be 1.0%, 0.3%, and 1.2% per patient-year, respectively. Also, Nakano and associates [17] report their linearized rates for thromboembolism, anticoagulant-related bleeding, and the composite thromboembolism and bleeding index for mitral valves to be 1.7%, 0.2%, and 1.9% per patient-year, respectively. However, the German report [16] yields greatly different results for mitral prostheses with the linearized rates for thromboembolism, anticoagulant-related bleeding, and the composite thromboembolism and bleeding index being 4.4%, 6.4%, and 10.8% per patient-year, respectively, with early and multiple events again excluded.

How is one to account for this extraordinary variability in results with the same prosthesis used in different high-quality health care systems? There is no clear answer. We have learned certain lessons about reporting results with mechanical heart valves over the years. First, the more frequently one interviews patients, the greater will be the number of incidents remembered by the patients, and thus the higher the incidence of complications. Second, the thromboembolic and bleeding complications recorded in any study may be important functions of the individual prosthesis, but they are probably also functions of other variables, for example, patient age, diet, inherent hematologic function, type of valvular disease, the capabilities of the person managing the patient's anticoagulation, or the intensity with which the information about complications is sought.

One other issue raised by this review is the efficacy of the previously published guidelines for reporting morbidity and mortality after cardiac valvular procedures [6]. The impact of other variables, especially patient factors, on the complications attributed to mechanical prostheses is becoming increasingly clear. We may be at a time when the previous guidelines need to be revised to achieve a more thorough assessment of the impact of other risk factors on the complications ascribed to mechanical cardiac valvular prostheses.

If a review such as this has any usefulness, it is that first, it brings together information from many studies to increase the sample size for each prosthesis; second, it may serve as a standard against which one may compare future results; third, it may serve as a stimulus for other cardiac surgical groups to investigate and report their results; and finally, it may encourage us to reassess the methods we use to evaluate mechanical valves.

	Footnotes

Top Footnotes Abstract Introduction The Study Valves Functional Mechanical... Review of Long-Term... Composite Thromboembolism and... Comment References

 
Address reprint requests to Dr Akins, Cardiac Surgical Unit, Massachusetts General Hospital, White 503, 32 Fruit St, Boston, MA 02114.

	References

Top Footnotes Abstract Introduction The Study Valves Functional Mechanical... Review of Long-Term... Composite Thromboembolism and... Comment References

 

1. Akins CW. Mechanical cardiac valvular prostheses. Ann Thorac Surg 1991;52:161–72.[Abstract]
2. Feldman HJ, Gray RJ, Chaux A, et al. Noninvasive in vivo and in vitro study of the St. Jude mitral valve prosthesis. Am J Cardiol 1982;49:1101–9.
3. Panidis IP, Ren JF, Kotler MN, et al. Clinical and echocardiographic evaluation of the St. Jude cardiac valve prosthesis: follow-up of 126 patients. J Am Coll Cardiol 1984;4: 454–62.[Abstract]
4. Carrier M, Martineau JP, Bonan R, Pelletier LC. Clinical and hemodynamic assessment of the Omniscience prosthetic heart valve. J Thorac Cardiovasc Surg 1987;93:300–7.[Abstract]
5. Kazui T, Komatsu S, Inoue N. Clinical evaluation of the Omniscience aortic disc valve prosthesis. Scand J Thorac Cardiovasc Surg 1987;21:173–8.[Medline]
6. Edmunds LH Jr, Clark RE, Cohn LH, Miller DC, Weisel RD. Guidelines for reporting morbidity and mortality after cardiac valvular operations. Ann Thorac Surg 1988;46:257–9.[Medline]
7. Vallejo JL, Gonzalez-Santos JM, Albertos J, et al. Eight years' experience with the Medtronic-Hall valve prosthesis. Ann Thorac Surg 1990;50:429–36.[Abstract]
8. Keenan RJ, Armitage JM, Trento A, et al. Clinical experience with the Medtronic-Hall valve prosthesis. Ann Thorac Surg 1990;50:748–53.[Abstract]
9. Fiore AC, Naunheim KS, D'Orazio S, et al. Mitral valve replacement: randomized trial of St. Jude and Medtronic-Hall prostheses. Ann Thorac Surg 1992;54:68–73.[Abstract]
10. Rábago G, Corbi P, Tedy G, et al. Five-year experience with the Medtronic Hall prosthesis in isolated aortic valve replacement. J Cardiac Surg 1993;8:85–8.[Medline]
11. Kim YI, Lesaffre E, Scheys I, Stalpaert G, Flameng WJ, Daenen WJ. The Monostrut versus Medtronic Hall prosthesis: a prospective randomized study. J Heart Valve Dis 1994;3:254–9.[Medline]
12. Burckhardt D, Striebel D, Vogt S, et al. Heart valve replacement with St. Jude Medical valve prosthesis: long-term experience in 743 patients in Switzerland. Circulation 1988;78(Suppl 1):18–24.
13. Kratz JM, Crawford FA Jr, Sade RM, Crumbley AJ, Stroud MR. St. Jude prosthesis for aortic and mitral valve replacement: a ten-year experience. Ann Thorac Surg 1993;56:462–8.[Abstract]
14. Jegaden O, Eker A, Delahaye F, et al. Thromboembolic risk and late survival after mitral valve replacement with the St. Jude Medical valve. Ann Thorac Surg 1994;58:1721–8.[Abstract]
15. Khan S, Chaux A, Matloff J, et al. The St. Jude Medical valve: experience with 1000 cases. J Thorac Cardiovasc Surg 1994;108:1010–20.[Abstract/Free Full Text]
16. Horstkotte D, Schulte HD, Bircks W, Strauer BE. Lower intensity anticoagulation therapy results in lower complication rates with the St. Jude Medical prosthesis. J Thorac Cardiovasc Surg 1994;107:1136–45.[Abstract/Free Full Text]
17. Nakano K, Koyanagi H, Hashimoto A, et al. Twelve years' experience with the St. Jude Medical valve prosthesis. Ann Thorac Surg 1994;57:697–703.[Abstract]
18. Aoyagi S, Oryoji A, Nishi Y, Tanaka K, Kosuga K, Oishi K. Long-term results of valve replacement with the St. Jude Medical valve. J Thorac Cardiovasc Surg 1994;108:1021–9.[Abstract/Free Full Text]
19. Ibrahim M, O'Kane H, Cleland J, Gladstone D, Sarsam M, Patterson C. The St. Jude Medical prosthesis: a thirteen-year experience. J Thorac Cardiovasc Surg 1994;108:221–30.[Abstract/Free Full Text]
20. Fernandez J, Laub GW, Adkins MS, et al. Early and late-phase events after valve replacement with the St. Jude Medical prosthesis in 1200 patients. J Thorac Cardiovasc Surg 1994;107:394–407.[Abstract/Free Full Text]
21. Akalin H, Çorapçiolu ET, Özyurda Ü, et al. Clinical evaluation of the Omniscience cardiac valve prosthesis: follow-up of up to 6 years. J Thorac Cardiovasc Surg 1992;103:259–66.[Abstract]
22. Copeland JG III. An international experience with the CarboMedics prosthetic heart valve. J Heart Valve Dis 1995;4:56–62.[Medline]
23. Burnett C. The clinical report. CarboMedics 1995;7:1–8.
24. Miller DC, Oyer PE, Mitchell RS, et al. Performance characteristics of the Starr-Edwards model 1260 aortic valve prosthesis beyond ten years. J Thorac Cardiovasc Surg 1984;88:193–207.[Abstract]
25. Perier P, Bessou JP, Swanson JS, et al. Comparative evaluation of aortic valve replacement with Starr, Björk, and porcine valve prostheses. Circulation 1985;72(Suppl 2):140–5.
26. Hackett D, Fessatidis I, Sapsford R, Oakley C. Ten year clinical evaluation of Starr-Edwards 2400 and 1260 aortic valve prostheses. Br Heart J 1987;57:356–63.[Abstract/Free Full Text]
27. Corcos T, Gandjbakhch I, Pavie A, et al. Long-term results of valve replacement with the Starr-Edwards silicone ball prostheses [Abstract]. Circulation 1987;76(Suppl 4):466.
28. Akins CW, Buckley MJ, Daggett WM, Austen WG, Hilgenberg AD, Jacobs ML. Ten-year follow-up of the Starr-Edwards prosthesis. In: Rabago G, Cooley DA, eds. Heart valve replacement and future trends in cardiac surgery. Mt. Kisco, NY: Futura, 1987:137–43.
29. Cobanoglu A, Fessler CL, Guvendik L, Grunkemeier G, Starr A. Aortic valve replacement with the Starr-Edwards prosthesis: a comparison of the first and second decades of follow-up. Ann Thorac Surg 1988;45:248–52.[Abstract]
30. Lund O, Knudsen MA, Pilegaard HK, Magnussen K, Nielsen TT. Long-term performance of the Starr-Edwards Silastic ball valves and St Jude Medical bi-leaflet valves. Eur Heart J 1990;11:108–19.[Abstract/Free Full Text]
31. Beaudet RL, Nakhle G, Beaulieu CR, Doyle D, Gauvin C, Poirier NL. Medtronic-Hall prosthesis: valve related deaths and complications. Can J Cardiol 1988;4:376–80.[Medline]
32. Nitter-Hauge S, Abdelnoor M. Ten-year experience with the Medtronic Hall valvular prosthesis. Circulation 1989;80(Suppl 1):43–8.[Abstract/Free Full Text]
33. Antunes MJ, Wessels A, Sadowski RG, et al. Medtronic Hall valve replacement in a third-world population group. A review of the performance of 1000 prostheses. J Thorac Cardiovasc Surg 1988;95:980–93.[Abstract]
34. Douglas PS, Hirshfeld JW Jr, Edie RN, Harken AH, Stephenson LW, Edmunds LH Jr. Clinical comparison of St. Jude and porcine aortic valve prostheses. Circulation 1985;72(Suppl 2):135–9.
35. Arom KV, Nicoloff DM, Kersten TE, Lindsay WG, Northrup WF III. St. Jude Medical prosthesis: valve-related deaths and complications. Ann Thorac Surg 1987;43:591–8.[Abstract]
36. DiSesa VJ, Collins JJ Jr, Cohn LH. Hematological complications with the St. Jude valve and reduced-dose Coumadin. Ann Thorac Surg 1989;48:280–3.[Abstract]
37. Duncan JM, Cooley DA, Reul GJ, et al. Durability and low thrombogenicity of the St. Jude Medical valve at 5-year follow-up. Ann Thorac Surg 1986;42:500–5.[Abstract]
38. Kinsley RH, Antunes MJ, Colsen PR. St. Jude Medical valve replacement. J Thorac Cardiovasc Surg 1986;92:349–60.[Abstract]
39. Rábago G, Martinell J, Fraile J, Andrade IG, Montenegro R. Results and complications with the Omniscience prosthesis. J Thorac Cardiovasc Surg 1984;87:136–40.[Abstract]
40. Miller DC, Oyer PE, Stinson, EB, et al. Ten to fifteen year reassessment of the performance characteristics of the Starr-Edwards model 6120 mitral valve prosthesis. J Thorac Cardiovasc Surg 1983;85:1–20.[Medline]
41. Schoevaerdts JC, Buche M, El Geriani A, et al. Twenty years' experience with the model 6120 Starr-Edwards valve in the mitral position. J Thorac Cardiovasc Surg 1987;94:375–82.[Abstract]
42. Cortina JM, Martinell J, Artiz V, Fraile J, Rábago G. Comparative clinical results with the Omniscience (STM1), Medtronic-Hall and Björk-Shiley convexo-concave (70°) prostheses in mitral valve replacement. J Thorac Cardiovasc Surg 1986;91:174–83.[Abstract]
43. Douglas PS, Hirshfeld JW Jr, Edie RN, Stephenson LW, Gleason K, Edmunds LH Jr. Clinical comparison of St. Jude and porcine mitral valve prostheses. J Cardiovasc Surg (Torino) 1988;29:128–33.[Medline]

This article has been cited by other articles:

				C. W. Akins, D. C. Miller, M. I. Turina, N. T. Kouchoukos, E. H. Blackstone, G. L. Grunkemeier, J. J.M. Takkenberg, T. E. David, E. G. Butchart, D. H. Adams, et al. Guidelines for reporting mortality and morbidity after cardiac valve interventions Eur. J. Cardiothorac. Surg., April 1, 2008; 33(4): 523 - 528. [Full Text] [PDF]

				C. W. Akins, D. C. Miller, M. I. Turina, N. T. Kouchoukos, E. H. Blackstone, G. L. Grunkemeier, J. J.M. Takkenberg, T. E. David, E. G. Butchart, D. H. Adams, et al. Guidelines for reporting mortality and morbidity after cardiac valve interventions. J. Thorac. Cardiovasc. Surg., April 1, 2008; 135(4): 732 - 738. [Full Text] [PDF]

				C. W. Akins, D. C. Miller, M. I. Turina, N. T. Kouchoukos, E. H. Blackstone, G. L. Grunkemeier, J. J.M. Takkenberg, T. E. David, E. G. Butchart, D. H. Adams, et al. Guidelines for Reporting Mortality and Morbidity After Cardiac Valve Interventions Ann. Thorac. Surg., April 1, 2008; 85(4): 1490 - 1495. [Full Text] [PDF]

				R. W. Emery, A. M. Emery, A. Knutsen, and G. V. Raikar Aortic Valve Replacement with a Mechanical Cardiac Valve Prosthesis Card. Surg. Adult, January 1, 2008; 3(2008): 841 - 856. [Full Text]

				G. J. Vlahakes Mechanical Heart Valves: The Test of Time... Circulation, October 16, 2007; 116(16): 1759 - 1760. [Full Text] [PDF]

				A. J. Bryan, C. A. Rogers, K. Bayliss, J. Wild, and G. D. Angelini Prospective randomized comparison of CarboMedics and St. Jude Medical bileaflet mechanical heart valve prostheses: Ten-year follow-up J. Thorac. Cardiovasc. Surg., March 1, 2007; 133(3): 614 - 622. [Abstract] [Full Text] [PDF]

				G. M. Palatianos, A. M. Laczkovics, P. Simon, J. L. Pomar, D. E. Birnbaum, H. H. Greve, and A. Haverich Multicentered European Study on Safety and Effectiveness of the On-X Prosthetic Heart Valve: Intermediate Follow-Up Ann. Thorac. Surg., January 1, 2007; 83(1): 40 - 46. [Abstract] [Full Text] [PDF]

				G. L. Grunkemeier, R. Jin, K. Im, R. Holubkov, E. D. Kennard, and H. V. Schaff Time-related risk of the St. Jude Silzone heart valve. Eur. J. Cardiothorac. Surg., July 1, 2006; 30(1): 20 - 27. [Abstract] [Full Text] [PDF]

				S. Sawaki, A. Usui, T. Abe, M. Yoshikawa, T. Akita, and Y. Ueda Late Mortality and Morbidity in Elderly Patients with Mechanical Heart Valves Asian Cardiovasc Thorac Ann, June 1, 2006; 14(3): 189 - 194. [Abstract] [Full Text] [PDF]

				C. Acar Invited commentary Ann. Thorac. Surg., August 1, 2005; 80(2): 494 - 494. [Full Text] [PDF]

				F. Dagenais, P. Cartier, P. Voisine, D. Desaulniers, J. Perron, R. Baillot, G. Raymond, J. Metras, D. Doyle, and P. Mathieu Which biologic valve should we select for the 45- to 65-year-old age group requiring aortic valve replacement? J. Thorac. Cardiovasc. Surg., May 1, 2005; 129(5): 1041 - 1049. [Abstract] [Full Text] [PDF]

				D. D. Potter, T. M. Sundt III, K. J. Zehr, J. A. Dearani, R. C. Daly, C. J. Mullany, C. G. A. McGregor, F. J. Puga, H. V. Schaff, and T. A. Orszulak Risk of repeat mitral valve replacement for failed mitral valve prostheses Ann. Thorac. Surg., July 1, 2004; 78(1): 67 - 72. [Abstract] [Full Text] [PDF]

				A. T. Tong, R. Roudaut, M. Ozkan, A. Sagie, M. S. A. Shahid, S. C. Pontes Jr, F. Carreras, S. E. Girard, S. Arnaout, R. F. Stainback, et al. Transesophageal echocardiography improves risk assessment of thrombolysis of prosthetic valve thrombosis: results of the international PRO-TEE registry J. Am. Coll. Cardiol., January 7, 2004; 43(1): 77 - 84. [Abstract] [Full Text] [PDF]

				K. Bando, J. Kobayashi, M. Hirata, T. Satoh, K. Niwaya, O. Tagusari, S. Nakatani, T. Yagihara, and S. Kitamura Early and late stroke after mitral valve replacement with a mechanical prosthesis: risk factor analysis of a 24-year experience J. Thorac. Cardiovasc. Surg., August 1, 2003; 126(2): 358 - 364. [Abstract] [Full Text] [PDF]

				R. W. Emery, G. J. Van Nooten, and P. J. Tesar The initial experience with the ATS Medical mechanical cardiac valve prosthesis Ann. Thorac. Surg., February 1, 2003; 75(2): 444 - 452. [Abstract] [Full Text] [PDF]

				J.B. Borman and C. De Riberolles Sorin BicarbonTM bileaflet valve: a 10-year experience Eur. J. Cardiothorac. Surg., January 1, 2003; 23(1): 86 - 92. [Abstract] [Full Text] [PDF]

				D. P. Korkolis, C. S. Passik, S. J. Marshalko, and G. J. Koullias Early bioprosthetic mitral valve "pseudostenosis" after complete preservation of the native mitral apparatus Ann. Thorac. Surg., November 1, 2002; 74(5): 1689 - 1691. [Abstract] [Full Text] [PDF]

C. W. Akins, A. D. Hilgenberg, G. J. Vlahakes, T. E. MacGillivray, D. F. Torchiana, and J. C. Madsen Results of bioprosthetic versus mechanical aortic valve replacement performed with concomitant coronary artery bypass grafting Ann. Thorac. Surg., October 1, 2002; 74(4): 1098 - 1106. [Abstract] [Full Text]