Structural valve deterioration in mitral replacement surgery: comparison of Carpentier-Edwards supra-annular porcine and perimount pericardial bioprostheses.

BACKGROUND: Bioprostheses preserved with glutaraldehyde, both porcine and pericardial, have been available as second-generation prostheses for valve replacement surgery. The performance with regard to structural valve deterioration with the Carpentier-Edwards supra-annular (CE-SAV) porcine bioprosthesis and the Carpentier-Edwards Perimount (CE-P) pericardial bioprosthesis (Baxter Healthcare Corp, Edwards Division, Santa Ana, Calif) was evaluated to determine whether there was a difference in mitral valve replacement. METHODS: The CE-SAV bioprosthesis was implanted in 1266 overall mitral valve replacements (isolated mitral, 1066; mitral in multiple, 200) and the CE-P bioprosthesis in 429 overall mitral valve replacements (isolated mitral, 328; mitral in multiple, 101). The mean age of the CE-SAV population was 64.2 +/- 12.2 years and that of the CE-P population, 60.7 +/- 11.7 years (P =.0001). For the study, structural valve deterioration was diagnosed at reoperation for explantation. RESULTS: The freedom from structural valve deterioration was evaluated to 10 years, and the freedom rates reported are at 10 years. For the overall mitral valve replacement groups, the actuarial freedom from deterioration was significant (P =.0001): CE-P > CE-SAV for 40 years or younger, 80% versus 60%; 41 to 50 years, 91% versus 61%; 51 to 60 years, 84% versus 69%; 61 to 70 years, 95% versus 75%. The older than 70-year group was 100% versus 92% (no significant difference). The actual freedom from structural valve deterioration also demonstrated the same pattern at 10 years: 40 years or younger, CE-P 82% versus CE-SAV 68%; 41 to 50 years, 92% versus 70%; 51 to 60 years, 90% versus 80%; 61 to 70 years, 97% versus 88%; and older than 70 years, 100% versus 97%. The independent risk factors of structural valve deterioration for the overall mitral valve replacement group were age and age groups and prosthesis type (CE-SAV > CE-P). The prosthesis type either in isolated replacement or in multiple replacement was not predictive of structural valve deterioration. The pathology of structural valve deterioration was different: 70% of CE-P failures were due to calcification and 57% of CE-SAV failures were due to combined calcification and leaflet tear. CONCLUSION: The actuarial and actual freedom from structural valve deterioration, diagnosed at reoperation, is greater at 10 years for CE-P than for CE-SAV bioprostheses. The mode of failure is different, and the cause remains obscure. Long-term evaluation is recommended, because the different modes of failure may alter the clinical performance by 15 and 20 years.     

Dynamic behavior of prosthetic aortic tissue valves as viewed by high-speed cinematography.

Using a valve testing apparatus of our own design and with a high-speed (600 to 800 frames per second) 16 mm movie camera, films were made of Hancock porcine, Carpentier-Edwards porcine, and Ionescu-Shiley bovine pericardial valves mounted in the aortic position and cycled under physiological conditions at 72 to 100 beats per minute. Fresh and explanted valves were observed using saline or 36.5% glycerol as the pumping solution. When fresh valves were studied using saline solution as the pumpint fluid, the Hancock and Carpentier-Edwards porcine valves showed high-frequency leaflet vibration, which increased in frequency with higher cycling rates. Abnormal leaflet motion was decreased when glycerol was used as the blood analogue. The Ionescu-Shiley bovine pericardial valve did not show abnormal leaflet motion under these conditions. Conclusions drawn from tissue valve testing studies that use excessively high pulsing rates and pressures (accelerated testing) and saline or water as pumping solutions cannot be transposed to predict the fate of tissue valves in a clinical setting.     

Ionescu-Shiley pericardial xenografts: follow-up of up to 6 years

The results of valve replacement with the Ionescu-Shiley pericardial xenograft compare favorably with results obtained with other bioprostheses. From March, 1977, to July, 1983, 497 Ionescu-Shiley pericardial valves were implanted in 463 patients at the University of Ottawa Heart Institute. There were 292 patients who had aortic valve replacement (AVR), 140 with mitral valve replacement (MVR), 28 with double valve replacement, and 3 with triple valve replacement. The survivors were followed regularly. Actuarial analysis of late results indicates an expected survival of 71% at 6 years for patients who underwent AVR and 72% at 3 years for patients who had MVR. The only valve-related deaths were due to endocarditis, which occurred at a rate of 3.9% per patient-year for aortic valves and 0.6% per patient-year for mitral valves. Despite a low usage of formal anticoagulation, embolic complications occurred at a rate of 1.4% per patient-year for aortic valves and 4.0% per patient-year for mitral valves. Five valves were removed for intrinsic failure after 36 to 72 months of follow-up. New York Heart Association Functional Class improved an average of 1.28 classes per patient.     

Unusual 25-year durability of an Ionescu-Shiley pericardial bioprosthesis

Ionescu-Shiley valve was withdrawn from clinical use in 1987 for its early structural failure after implantation. This was due to valve design rather than the natural properties of bovine pericardium itself. We describe the unexpected 25-year survival of an Ionescu-Shiley bioprosthesis in the mitral and tricuspid positions, implanted to treat endomyocardial fibrosis. This report makes 2 important points: (1) pannus overgrowth may be a favorable determinant of the durability of xenografts, and (2) bovine pericardial valves may have excellent hemodynamic performance and tissue durability for more than 20 years in the mitral position even in young patients.     

Early mechanical failures of the Hancock pericardial xenograft

From August 1981 to July 1984, a total of 97 Hancock pericardial xenografts were implanted in 84 patients, whose ages ranged from 13 to 75 years (mean 55.7 +/- 13). Mitral value replacement was performed in 17, aortic valve replacement in 54, and mitral-aortic valve replacement in 13. Operative survivors were reevaluated from July to September 1985. Cumulative duration of follow-up is 167 patient-years (range 0.5 to 4.1 years), and follow-up is 99% complete. The overall late mortality (at 4 years) is 3.6% +/- 1.4% per patient year, and the actuarial survival rate is 95.4% +/- 3% for aortic valve replacement, 74.7% +/- 16.5% for mitral valve replacement, and 67.1% +/- 20.7% for mitral-aortic valve replacement. One patient sustained a thromboembolic event after mitral valve replacement, but no such complications occurred after aortic or mitral-aortic valve replacement. Actuarial freedom from embolism at 4 years is 100% for aortic and mitral-aortic valve replacement and 93.3% +/- 6.4% for mitral valve replacement. Reoperation for Hancock pericardial xenograft dysfunction was performed in seven patients (five aortic and two mitral-aortic). In the aortic valve replacement group the causes were endocarditis in one, paravalvular leak in one, and primary tissue failure in three; all survived reoperation. The two patients with mitral-aortic valve replacement required reoperation because of primary tissue failure of both Hancock pericardial xenografts, and one died. All values explanted because of primary tissue failure showed commissural tears causing severe prosthetic regurgitation. Calcium deposits were severe in one and mild but unrelated to the cusp rupture in another. Collagen disarray was seen only at the site of the tears, whereas the collagen structure was well preserved in the intact parts of the cusps. Four patients with aortic valve replacement and one with mitral valve replacement show evidence of Hancock pericardial xenograft failure and are awaiting reoperation. The actuarial freedom from primary tissue failure at 4 years is 74.3% +/- 9.8% for aortic and 78.9% +/- 13.2% for mitral Hancock pericardial xenografts. At medium-term follow-up, the Hancock pericardial xenograft has shown poor durability and an extremely high rate of early mechanical failure, especially in the aortic position. These observations suggest the need for a close follow-up of Hancock pericardial xenograft recipients and possibly elective reoperation in asymptomatic patients with clinical evidence of prosthetic failure. These results have led us to discontinue the clinical use of this pericardial xenograft.     

Long-term results of bioprosthetic mitral valve replacement: the pericardial perspective

Pericardial valve bioprostheses were introduced in early 1970s and were widely used in the 1980s. The longterm results with the Ionescu-Shiley valve, the first commercially available pericardial valve, were disappointing because of high rate cusp tears during the first decade after implantation. The enthusiasm for this type of bioprosthetic valve was further hampered by the premature failure of the Hancock pericardial valve. The long-term results of aortic valve replacement with the Carpentier-Edwards pericardial valve, which was introduced in 1981, indicated that that valve was durable and the issue of cusp tears had been resolved by an appropriate design. This knowledge prompted surgeons to revisit the merits of pericardial valves for mitral valve replacement and several other pericardial valves are now commercially available. The largest data on long-term results are with the Carpentier-Edwards pericardial mitral valve. The reported freedom from structure valve failure ranged from 69% to 85% at 10 years in patient population with mean age of 60 to 70 years. Young age is a major determinant of valve failure, which is largely due to calcification. There are also long-term data, albeit more limited on the Sorin Pericarbon and Mitroflow valves used for mitral valve replacement. This paper review the published experience with various pericardial bioprosthetic valves used for mitral valve replacement during the past 3 decades.     

The behavior of pericardial versus porcine valve xenografts in the growing sheep model

The comparative long-term behavior of the pericardial versus the porcine bioprostheses is not yet known. The need for long follow-up times to answer this question makes the growing sheep model an attractive alternative, given its ability to induce early valve degeneration. Sixty-three sheep, 12 to 16 weeks old, were operated on and received 39 porcine (11 Xenomedica, 10 Carpentier-Edwards S, nine Hancock I standard, and nine Hancock I T6-treated) and 24 pericardial (14 Mitroflow and 10 Ionescu-Shiley low profile) prostheses of clinical quality in the tricuspid position. Of the 52 operative survivors (32 received porcine valves and 20 received pericardial bioprostheses), six animals (five pericardial and one porcine) were eliminated because of bioprosthetic infection. Late sudden death before the scheduled killing occurred significantly more often (p less than 0.0001) in the pericardial (8/15 or 53%) than in the porcine group (1/31 or 3%). Calcium content of the explanted valves was significantly correlated with time in the pericardial group and the Xenomedica porcine prostheses (p less than 0.05) but not in the Hancock I and Carpentier-Edwards S valves, where it was only marginally significant (0.1 greater than p greater than 0.05). Linear regression analysis of tissue calcium content showed a similar slope for the pericardial group and Xenomedica porcine valves, in comparison with the remaining porcine valves. Comparison between the two lines using covariance analysis demonstrated a statistically significant difference between them, which shows that the pericardial and Xenomedica porcine valves appear to reach higher levels of calcification in a shorter follow-up time than the Hancock I, standard and T6-treated, and the Carpentier-Edwards S valve in this animal model.     

A case report: Carpentier-Edwards porcine bioprosthesis malfunction due to the stent dehiscence at 17 years after the implantation in the mitral position

A 53-year-old female had undergone mitral valve replacement with Carpentier-Edwards (C-E) porcine bioprosthesis for mitral valve regurgitation at the other hospital in November, 1981. Postoperative clinical course was uneventful, since she was referred from the other hospital in 1990. In December, 1997, she had sudden complaint of shortness of breath on effort, and the chest X-ray showed pulmonary congestion and increase of cardio-thoracic ratio. Echocardiography and catheterization revealed severe mitral regurgitation due to bioprosthesis malfunction and aortic valve regurgitation. Combined mitral and aortic valve replacement was successfully performed with mechanical valves in February, 1998. The explanted C-E porcine bioprosthesis showed the commissural dehiscence from only one of the three stents without any leaflet perforation, commissural tear, pannus overgrowth, impaired leaflet mobility and leaflet deterioration or calcification. This case suggested the variety of malfunction of C-E porcine bioprosthesis and the limitation of its long-term durability.     

Middle term follow-up and comparative study of valve replacement with four kinds of new model bovine pericardial xenografts

Our early clinical experience (up to 4 year's follow-up) with four new pericardial xenografts were reviewed. During the period July 1983 to December 1986, 148 Ionescu-Shiley Pericardial Xenografts (ISL) in 130 patients, 68 Carpentier-Edwards pericardial xenografts (CEP) in 65, 32 Mitroflow pericardial xenografts (MF) in 29 and 36 Hancock pericardial xenografts (HP) in 29 have been implanted. The actuarial survival rates at 3.3 years are 89.9 +/- 2.7% for ISL, 92.3 +/- 3.3% for CEP, 93.1 +/- 4.7% for MF and 93.1 +/- 4.7% for HP. Fifteen cases of primary tissue failure (PTF) were caused in all groups but CEP. The actuarial free rates from PTF at 3.3 years were 92.9 +/- 2.4% for ISL, 100% for CEP, 95.5 +/- 4.4% for MF, 82.6 +/- 7.9% for HP. All bioprostheses explanted because of PTF showed commissural tears occurred at the top of the stent posts or at the edge of the stent. In this respect, it is the reason why the cases with CEP were free from PTF that CEP has been achieved to be improved its frame design. The incidences of prosthetic valve endocarditis were not different among these kinds of bioprosthetic valves. The free rates from thromboembolism at 3.3 years were 97.5 +/- 1.5% for ISL, 98.3 +/- 1.7% for CEP, 96.0 +/- 3.9% for MF and 88.7 +/- 6.1% for HP. There was no patient with CEP and MF suffered from thromboembolism with sinus rhythm. In comparison of these 4 valves, we conclude that CEP is useful clinically because of its satisfactory durability and antithrombogenicity.     

Primary tissue failure in pericardial heart valves

A number of centers have recorded a significant incidence of primary tissue failure with the standard Ionescu-Shiley pericardial valve. In most cases severe regurgitation was caused by leaflet tears adjacent to the edge of the cloth-covered stent. Our early clinical experience (up to 4 years' follow-up) with two new pericardial valves (Ionescu-Shiley low-profile and Hancock pericardial valves) has shown that primary tissue failure also occurs in these new valves. In vitro accelerated fatigue studies on seven of these valves (size 29 mm) showed that in vitro premature leaflet failure was caused by abrasion of the leaflet on the cloth-covering at the edge of the stent. Clinically, endothelialization and host tissue ingrowth on the cloth and the leaflets at the edge of the frame greatly reduced the amount of abrasion and the incidence of tissue failure. In seven of the eight explanted valves studied, leaflet tears occurred at the top of the stent posts where there was less endothelialization and tissue ingrowth, close to the points where sutures pass through the leaflets. It is likely that both abrasion and stress concentration around these sutures contributed to the tissue failures in the clinical valves.     

Rest and exercise hemodynamics following aortic valve replacement. A comparison between 19 and 21 mm Ionescu-Shiley pericardial and Carpentier-Edwards porcine valves

When aortic valve replacement is performed in a patient with a small anulus, significant obstruction of the left ventricular outflow tract may remain. Most prostheses are obstructive in the smaller sizes, and enlargement of the aortic anulus may be required to allow placement of a larger valve. To evaluate the hemodynamic performance of two commonly used tissue prostheses, the Ionescu-Shiley pericardial and Carpentier-Edwards porcine valves, 22 patients with either the 19 or 21 mm size were electively studied at rest and after exercise at a mean of 15 months after operation. The resting mean transvalvular gradient for 19 mm Ionescu-Shiley pericardial valves (n = 7), 10.6 +/- 9.2 mm Hg, was significantly lower than that for 19 mm Carpentier-Edwards valves (n = 3), 33.3 +/- 2.1 mm Hg, p less than 0.01. Following exercise, the mean gradient for 19 mm Ionescu-Shiley pericardial valves rose only to 13.8 +/- 8.5 mm Hg. No exercise data were available for the 19 mm Carpentier-Edwards valve. Among patients with 21 mm Ionescu-Shiley pericardial valves (n = 7), the mean transvalvular gradient at rest was 5.6 +/- 9.5 mm Hg, not significantly different from that of patients with 21 mm Carpentier-Edwards valves (n = 5), 9.8 +/- 18.3 mm Hg. After exercise, the gradients rose to 16.0 +/- 10.0 mm Hg and 25.5 +/- 23.8 mm Hg for the Ionescu-Shiley pericardial and Carpentier-Edwards valves, respectively (no statistical significance). Cardiac index was not different between groups. Gradients were not significantly higher in patients with body surface areas greater than 1.5 m2. It is concluded that the 19 and 21 mm Ionescu-Shiley pericardial valves possess excellent hemodynamics, even after exercise. This valve appears hemodynamically superior to the Carpentier-Edwards valve, particularly in the 19 mm size. Procedures to enlarge the aortic anulus are usually unnecessary when small Ionescu-Shiley pericardial valves are used, even in patients who have large body surface areas.     

The Hancock pericardial xenograft: incidence of early mechanical failures at a medium-term follow-up

The Hancock pericardial xenograft has been used in our Institution since August 1981 as an alternative to porcine bioprostheses. Up to July 1984, 97 Hancock pericardial xenografts have been implanted in 84 patients; of 76 operative survivors with a mean age of 55.2±13 years (range 13–75 years), 50 had undergone aortic valve replacement, 16 mitral valve replacement and 10 mitral-aortic valve replacement. Follow-up ranged from 0.5 to 5.2 years with a cumulative duration of 239 patient/years and is 99% complete. Actuarial survival is 92%±4% for patients with aortic valve replacement and 84%±10% for patients with mitral valve replacement at 5 years, and 77%±14% for those with mitral-aortic valve replacement at 4 years. Thromboembolic episodes occurred in 2 patients (1 after aortic and 1 after mitral valve replacement). The actuarial freedom from emboli is 100% for patients with mitral-aortic valve replacement at 4 years, and 96%±3% for patients with aortic and 93%±6% for patients with mitral valve replacement at 5 years. Reoperation was performed in 13 patients (9 aortic, 2 mitral and 2 mitral-aortic valve replacements), because of endocarditis in 3 (2 aortic and 1 mitral valve replacement), paravalvular leak in 1 (aortic valve replacement), and primary tissue failure in 9 (6 aortic, 1 mitral and 2 mitral-aortic valve replacements). Actuarial freedom from primary tissue failure is 72%±9% for aortic and 83%±8% for mitral Hancock pericardial xenografts at 5 years. Eleven xenografts explanted because of primary tissue failure were studied pathologically. All showed commissural tears with gross regurgitation; calcium deposits were severe in 2, mild but unrelated to the tears in 2 and absent in 7. Collagen disarray was observed at the site of cusp rupture while the collagen was well preserved in the intact areas of the leaflets. Our results show that: 1) Hancock pericardial xenografts have a high rate of early primary tissue failure, 2) primary tissue failure is caused by cusp rupture at the commissures and can be considered fatigue-induced, 3) tissue calcification does not influence the durability of pericardial xenografts which do not represent a valid alternative to porcine bioprostheses.     

Comparison of Carpentier-Edwards pericardial and supraannular bioprostheses in aortic valve replacement.

OBJECTIVE: This study aimed at calculating and comparing the long-term outcomes of patients after aortic valve replacement with the Carpentier-Edwards bovine pericardial and porcine supraannular bioprostheses using microsimulation. METHODS: We conducted a meta-analysis of eight studies on the Carpentier-Edwards pericardial valves (2,685 patients, 12,250 patient-years) and five studies on the supraannular valves (3,796 patients, 20,127 patient-years) to estimate the occurrence rates of valve-related events. Eighteen-year follow-up data sets were used to construct age-dependent Weibull curves that described their structural valvular deterioration. The estimates were entered into a microsimulation model, which was used to calculate the outcomes of patients after aortic valve replacement. RESULTS: The annual hazard rates for thrombo-embolism after aortic valve replacement were 1.35% and 1.76% for the pericardial and supraannular valves, respectively. For a 65-year-old male, median time to structural valvular deterioration was 20.1 and 22.2 years while the lifetime risk of reoperation due to structural valvular deterioration was 18.3% and 14.0%, respectively. The life expectancy of the patient was 10.8 and 10.9 years and event-free life expectancy 9.0 and 8.8 years, respectively. CONCLUSIONS: The microsimulation methodology provides insight into the prognosis of a patient after aortic valve replacement with any given valve type. Both the Carpentier-Edwards pericardial and supraannular valve types perform satisfactorily, especially in elderly patients, and show no appreciable difference in long-term outcomes when implanted in the aortic position.     

Long-term clinical results with the Ionescu-Shiley pericardial xenograft

From 1977 to 1987, 829 Ionescu-Shiley pericardial valves (Shiley, Inc., Irvine, Calif.) were implanted in 766 patients at the University of Ottawa Heart Institute. There were 476 patients who had aortic valve replacement, 234 who had mitral valve replacement, and 44 who had double valve replacement. The standard-profile design was used in 508 patients and the low-profile design in 321 patients. Follow-up was obtained for 97% of patients, with calculation of event-free probabilities. At 10 years the overall probability of freedom from structural failure was 48% +/- 7% after aortic valve replacement, 44% +/- 15% after mitral valve replacement, and 79% +/- 11% after double valve replacement. Although at 5 years the probability of failure was statistically lower with the low-profile design, this favorability was lost by 6 years. Freedom from structural failure was only 47% +/- 7% for the standard-profile valve at 10 years. Thus the probability of freedom from reoperation was only 46% +/- 7% after aortic valve replacement, 39% +/- 6% after mitral valve replacement, and 65% +/- 20% after double valve replacement at 10 years. Thromboembolism occurred in 69 patients, for a predicted freedom from this complication at 10 years of 79% +/- 3% after aortic, 73% +/- 7% after mitral, and 96% +/- 4% after double valve replacement. There were 31 cases of endocarditis. The 10-year predicted freedom from endocarditis, therefore, was 86% +/- 3% after aortic, 98% +/- 1% after mitral, and 97% +/- 1% after double valve replacement. A total of 221 operative and late deaths were recorded in this series. Prosthetic valve failure accounted for 27% of late deaths. The 10-year survival rates were estimated to be 56% +/- 5% (aortic valve replacement), 54% +/- 6% (mitral valve replacement), and 51% +/- 8% (double valve replacement). We concluded that the Ionescu-Shiley pericardial xenograft provides less than optimal clinical performance and its use has been discontinued.     

Hemodynamic performance of an unstented xenograft mitral valve substitute

OBJECTIVE: Stentless mitral xenografts offer potential clinical benefits because they mimic the normal bileaflet mitral valve. How best to implant them and their hemodynamic performance and durability, however, remain unknown. METHODS: A stentless porcine mitral xenograft valve (Medtronic physiologic mitral valve) was implanted in 7 sheep with papillary muscle sewing tubes attached with transmural left ventricular sutures. Radiopaque markers were inserted on the leaflets, annular cuff, papillary tips, and left ventricle. After 10 +/- 5 days, the animals were studied with biplane videofluoroscopy to determine 3-dimensional marker coordinates at baseline and during dobutamine infusion. Transesophageal echocardiography assessed mitral regurgitation and valvular gradients. Mitral annular area was calculated from the annular markers. Physiologic mitral valve leaflet and annular dynamics were compared with 8 native sheep valves. RESULTS: Average mitral regurgitation grade at baseline was 1.2 +/- 1.0 (range, 0-4), and the mean transvalvular pressure gradients were 3.6 +/- 1.3 and 6.2 +/- 2.2 mm Hg during baseline and dobutamine infusion, respectively. Xenograft mitral annular area contraction throughout the cardiac cycle was reduced (6% +/- 6% vs 13% +/- 4% for physiologic mitral valve and control valve, respectively; P =.03). Physiologic mitral valve leaflet geometry during closure differed from the native valve, with the anterior leaflet being convex to the atrium and with little motion of the posterior leaflet. Three animals survived more than 3 months; good healing of the annular cuff and papillary muscle tubes was demonstrated. CONCLUSION: This stentless xenograft mitral valve substitute had low gradients at baseline and during stress conditions early postoperatively, with mild mitral regurgitation. Preliminary analysis of healing characteristics appeared favorable at 3 months. Additional studies are needed to determine long-term xenograft mitral valve performance and resistance to calcification.     

Porcine versus pericardial bioprostheses: a comparison of late results in 1,593 patients

From 1976 to 1988, 1,593 patients underwent valve replacement with a porcine (878 patients) or a pericardial bioprosthesis (715 patients). There were 701 aortic, 678 mitral, and 214 multiple-valve replacements. Follow-up was obtained for 1,559 patients (98%). Early mortality was 9% (79 patients) in the porcine valve group and 5% (37 patients) among patients with a pericardial valve (p less than 0.01). Late survival after replacement with porcine valves was 80% +/- 1% and 62% +/- 3% at 5 and 10 years, respectively. With pericardial valves, 5-year survival was 79% +/- 2%. Among valve-related complications, rates of freedom from thromboembolism, endocarditis, and hemorrhage after 6 years were similar for both valve groups. Freedom from reoperation at 6 years was also similar after aortic (96% versus 91%) or multiple-valve replacement (95% versus 88%). However, for mitral valve replacement, freedom from reoperation was significantly better with porcine valves than with pericardial valves at 6 years (92% versus 68%; p less than 0.001). This difference was mainly due to the Ionescu-Shiley valve, which accounted for 83% of primary tissue failures among pericardial bioprostheses implanted in the mitral position (10/12 patients). After 6 years, freedom from primary tissue failure of mitral valves was 92% +/- 2% with porcine and 70% +/- 11% with pericardial bioprostheses (p less than 0.0001). The degree of clinical improvement among survivors was similar with both valve types. Thus, in the aortic position, pericardial valves compare with porcine valves up to 6 years, whereas in the mitral position, the durability of the former is significantly less, mainly because of the suboptimal performance of the Ionescu-Shiley pericardial bioprosthesis.     

Failure of Hancock pericardial xenografts: is prophylactic bioprosthetic replacement justified?

The incidence of major valve-related complications was evaluated in a series of patients in whom the Hancock pericardial xenograft was used for aortic (AVR; n = 84), mitral (MVR; n = 17) and mitral-aortic (MAVR; n = 13) valve replacement. At 7 years actuarial survival is 66% +/- 8% after AVR, 64% +/- 13% after MVR, and 41% +/- 15% after MAVR, whereas actuarial freedom from valve-related death is 79% +/- 7% after AVR, 78% +/- 13% after MVR, and 81% +/- 12% after MAVR. Actuarial freedom from thromboemboli and anticoagulant-related hemorrhage at 7 years is 93% +/- 4% and 98% +/- 2% after AVR and 83% +/- 10% and 88% +/- 11% after MVR; no such complications occurred after MAVR. Structural valve deterioration determined at reoperation, at autopsy, or by clinical investigation was observed in 34 patients with AVR (10.0 +/- 0.2%/patient-year), in 10 with MVR (10.6 +/- 3.3%/patient-year), and in 9 with MAVR (16.6 +/- 5.5%/patient-year). After AVR, 19 patients underwent reoperation and 2 died before reoperation; 4 patients with MVR underwent reoperation, and 7 patients with MAVR underwent reoperation and 1 died before reoperation. Seventy-eight percent of the current survivors (13 patients with AVR, 7 with MVR, and 1 with MAVR) have clinical evidence of valve failure. At 7 years actuarial freedom from structural deterioration of the Hancock pericardial xenograft is 25% +/- 7% after AVR, 29% +/- 14% after MVR, and 0% after MAVR.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of reoperation findings of the Carpentier-Edwards (standard) bioprosthesis and the St Jude bioimplant (formerly Liotta) in the mitral position

Between 1986 and 1996, 50 patients with Carpentier-Edwards porcine bioprostheses and 211 with a St Jude bioprosthesis underwent reoperation because of structural valve deterioration. Structural valve deterioration was defined as an intrinsic abnormality of the prosthesis (leaflet disruption, calcification, leaflet thickening, etc.) that caused stenosis or regurgitation found on physical examination and echocardiography. Fifteen of the Carpentier-Edwards bioprosthesis group were male and 35 were female. Eighty-two of the St Jude group were male and 129 female. The mean age at reoperation was 33.88 +/- 10.31 years (range 19-70) for the Carpentier-Edwards group and 39.03 +/- 9.97 years (range 20-70) for the St Jude group. The average duration was 94.32 +/- 3.83 months for the Carpentier-Edwards group and 73.76 +/- 1.44 months for the St Jude group (P < 0.001). The mean aortic cross-clamp time was 67.4 min (minimum 32, maximum 210) for the St Jude group and 63.21 min (minimum 36, maximum 230) for the Carpentier-Edwards group. Reoperative hospital mortality was 10% (5/50) in the Carpentier-Edwards group and 7.1% (15/211) in the St Jude group (P > 0.05). Late failure modes of the bioprostheses were defined for the purposes of this study as calcification, stenosis and torn leaflets. Of the Carpentier-Edwards group, seven patients (14%) developed calcification, six patients (12%) developed stenosis and 13 patients (26%) developed leaflet tears. Of the St Jude group, the incidences were 22 patients (10%), 67 patients (31.8%) and 87 patients (41%), respectively. This study indicates that the Carpentier-Edwards bioprosthesis is more durable than the St Jude. The St Jude bioprosthesis tended to develop leaflet tears and linear calcification in female patients, and nodular calcification in male patients.     

Clinical experience with porcine xenografts in the mitral position

In a 7-year period, 120 porcine xenografts, 16 of Hancock and 104 of Carpentier-Edwards type, were implanted in the mitral position in patients with isolated mitral valve disease. The operative mortality was 4.2%. The actuarial survival after 5 years was 93%. Death during the observation period was valve-related in two cases. Three valves had to be exchanged, one because of calcification and two because of prosthetic endocarditis. The risk of contracting prosthetic endocarditis was 0.38% per patient year. All the patients received peroral anticoagulant medication indefinitely. Two minor embolic episodes occurred, both in the first 6 post-operative months. The probability of freedom from thromboembolism was thus 98.2% after 7 years. In functional evaluation of 92 patients observed for at least 6 months, more than 90% were in NYHA class I or II. Porcine xenograft is a good valve substitute in the mitral position with a low incidence of complications, especially of thromboembolism, in patients on maintenance anticoagulant therapy. Long-term observations of this type of valve substitute are not yet available, however.     

Immediate structural valve deterioration of 27-mm Carpentier-Edwards aortic pericardial bioprosthesis

We describe two cases of immediate structural valve deterioration of the 27-mm Carpentier-Edwards pericardial valve. Tissue characteristics of bovine pericardium and the possible mechanism of failure are discussed.