Porcine Bioprosthesis Research Articles

Comparative study of primary tissue failure between porcine (Hancock and Carpentier-Edwards) and bovine pericardial (Ionescu-Shiley) bioprostheses in the aortic position at five- to nine-year follow-up

Retrospective follow-up data on 458 consecutive patients who received a Hancock, Carpentier-Edwards (C-E) or Ionescu-Shiley (I-S) bioprosthesis in the aortic valve position between April 1978 and December 1981 are reviewed. A total of 461 valves (184 Hancock, 131 C-E and 146 I-S) were available for study of the incidence of primary tissue valve failure after 5 to 9 years of follow-up. Cumulative follow-up was 1,016 patient-years for patients with Hancock valve, 688 for the C-E and 767 for the I-S group. Of the 397 prostheses at risk (154 Hancock, 120 C-E and 123 I-S), 36 instances of primary tissue valve failure occurred (12 Hancock, 7 C-E and 17 I-S). On an actuarial basis, the calculated probability of freedom from primary tissue valve failure was 88 ± 4% for the Hancock group, 87 ± 6% for the C-E and 51 ± 17% for the I-S at 9 years. The linear incidence of tissue valve failure was 1.2 failing valves per 100 patient-years for the Hancock group, 1 for the C-E and 2.2 for the I-S. In a cohort of patients older than 40 years of age at the time of valve replacement, the rate of freedom from primary failure was 98 ± 1%, 87 ± 9% and 44 ± 22% for the Hancock, C-E and I-S groups, respectively, at 9 years. Comparison of actuarial curves disclosed a meaningful difference between the pericardial valve and the Hancock and C-E porcine bioprostheses at 9-year follow-up. These data should have some bearing of practical import not only when comparing different types of bioprostheses, but especially when recommending the appropriate valve replacement for the individual patient.

Ventricular aneurysms and other lesions produced by the struts of bioprosthetic valves implanted in sheep

Damage to the posterolateral wall of the left ventricle was found in eight of approximately 700 sheep undergoing mitral valvular replacement as part of animal model studies of bioprosthetic valves. The damage consisted of left ventricular aneurysms in five animals, subacute rupture of the left ventricle in one, acute left ventricular laceration in one, and endocardial scarring in one. Six of the eight bioprostheses were bovine pericardial valves, including five low-profile valves and one standard valve; of the two porcine bioprostheses, one was intentionally oversized and the other was a low-profile supra-annular valve. In each of these animals the damage appeared to have been caused by contact between the most posterior strut of the bioprosthesis and the left ventricular wall.

Do heart valve bioprostheses degenerate for metabolic or mechanical reasons?

Although heart valve bioprostheses provide a normal quality of life, their durability is still of great concern. Their durability failure is defined as "degeneration," which is considered to be a consequence of metabolic factors. In this study, we demonstrate that mechanical and design factors can also be responsible for bioprosthesis failure. Large numbers of porcine and pericardial bioprostheses were tested in a fatigue-testing system in which the test conditions were proved to be reproducible and accurate by a laser Doppler anemometer. The results have allowed us to define causes of failure, previously insufficiently stressed, in each type of valve tested. There is a clear difference in factors influencing tissue disruption between porcine and pericardial valves. We have compared these in vitro results with in vivo clinical findings. The main inferences are as follows: (1) Bioprostheses rupture and fail in the same fashion in both in vitro and in vivo studies. (2) Mechanical and design factors are involved in tissue failure. (3) The in vitro/in vivo durability ratio is not 1:1. This ratio depends on the test conditions. (4) Pericardial valves fail because of damage during closure, whereas porcine valves are damaged during both opening and closing (mostly opening) because of design features. (5) Once one cusp fails and prolapses, the other cusps will fail in an accelerated fashion. (6) In vitro durability of 100 X 10(6) cycles can be considered excellent and is an achievable goal. (7) Variability is the key impediment to predicting the durability of bioprostheses. Valves can fail within 2 to 3 million cycles or can last more than 100 million cycles. Similarly, bioprostheses may require explantation within a few months or can last 10 to 13 years in patients. (8) Fatigue testing is an excellent and valuable tool to elucidate the mechanical factors responsible for this variability.

Early and late results of valvular surgery in the elderly.

From January, 1979 to June, 1986, 70 consecutive elderly patients (30 males and 40 females) age 65 years or older underwent open heart surgery for valvular heart diseases at Mitsui Memorial Hospital in Tokyo. Seventeen patients (24.3%) were septuagenarians. Porcine bioprosthesis (Carpentier-Edwards) was inserted for the mitral and the tricuspid position, and mechanical valve (Björk-Shiley or Duromedics) for the aortic position. Every patients received an anticoagulant (warfarin) postoperatively all through the follow-up period. The mean duration of follow-up was 43 months and the cumulative follow-up was 195 patient-years. Fifteen patients died in hospital after operation, giving an operative mortality rate of 21.4%. Cardiac death occurred in only 5 and the other 10 patients died of other causes such as sepsis, cerebrovascular accident, and agranulocytosis, showing that these patients were already in an advanced stage of cardiac failure. Late death occurred in 5 patients, but there was no clear-cut cardiac death documented. The actuarial survival rates at 3 years and 5 years were 71.6% and 65.9% for all patients, and 90.5% and 83.3% for early survivors. The functional and symptomatic improvement of 49 late survivors was remarkable. Thirty-eight patients (77.6%) are now NYHA class I and II. The incidence of thromboembolic and hemorrhagic episodes was fairly low--2% and 3% per patient year, respectively. Although the operative mortality is rather high in this study, it is clear that the surgical management of elderly patients with life-threatening valvular lesions results in substantial functional improvement and good prognosis in surviving patients.(ABSTRACT TRUNCATED AT 250 WORDS)

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.(ABSTRACT TRUNCATED AT 250 WORDS)

Intrinsic Failure of Hancock Mitral Bioprostheses: 10- to 15-Year Experience

Hancock porcine bioprostheses have been implanted in the mitral position at the National Institutes of Health since July, 1970. Eight models (330, 330A, 330B, 330C, 332, 340, 341, and 342) were used during a 54-month period ending December, 1974, and 100 consecutive surviving patients were evaluated for subsequent bioprosthetic valve failure and prosthesis-related complications by annual clinic examinations and serial hemodynamic studies. Actuarial patient survival was 76 ± 4%, 51 ± 5%, and 30 ± 6% after 5, 10, and 15 years, respectively. Intrinsic valve failure, defined as structural degeneration of bioprosthetic tissue or stent geometry alteration or both, in the absence of prior infection, occurred in 23 patients. The linear occurrence rate of bioprosthetic valve failure was 0.2%, 5%, and 15% per patient-year, and it affected 1 patient, 14 patients, and 8 patients at sequential 5-year milestones. The actuarial freedom from valve failure was 99 ± 1%, 75 ± 6%, 58 ± 8%, and 40 ± 12% after 5, 10, 12, and 14 years, respectively. The valve durability of early Hancock bioprostheses (models 330 through 341; N = 39) was not appreciably different from that of the current model 342 valves (N = 61). However, an increased incidence of intrinsic valve failure was observed for the first polypropylene-stented valve type (model 330) compared with the currently available model 342 valve (8/16, 50%, versus 12/61, 20%; p = 0.034). The yearly occurrence rate of prosthesis-related complications remained constant, but the rate of intrinsic valve failure increased in a progressive, nonlinear fashion. The high intrinsic failure rate of the Hancock porcine bioprosthesis after 10 to 12 years has moderated our initial enthusiasm for this valve in the mitral position, and has resulted in more frequent implantations of mechanical valve substitutes at this institution.

Emergency reoperation for primary tissue failure of porcine bioprostheses

Emergency reoperation for primary tissue failure of porcine bioprostheses

Late failure of bioprosthesis excision for treatment of recurrence of Pseudomonas aeruginosa tricuspid valve endocarditis previously treated by valve replacement

ostium of the left coronary artery and there was a collection of blood under tension between the aorta and pulmonary trunk (Figs. 3 and 4). The aortic valve was necrotic and infection extended through the noncoronary sinus into the right atrium as a 1 by 2 cm fibrinous mass. The tricuspid valve was normal. The aortic root was replaced by a Dacron tube graft containing a porcine bioprosthesis and the coronary arteries were reimplanted into the graft. The patient was treated for an additional 4 weeks with intravenous ampicillin and oral rifampin. Except for placement of a permanent pacemaker for complete heart block that occurred on the sixth postoperative day, her recovery was otherwise uneventful. She remained afebrile and her blood cultures were sterile 6 months later. H. parainfluenzae is a fastidious, Gram-negative coccobacillus that inhabits the upper respiratory tract in approximately 10% of healthy persons.* The organism characteristically grows slowly and blood cultures in patients with infective endocarditis frequently do not become positive until 7 to 10 days after collection. Similarly, the initial clinical illness is often indolent, with symptoms extending over weeks to months.3 As a consequence, large, bulky valvular vegetations are demonstrable by echocardiography in a majority of patients.4 Our patient’s infection was unusual in the degree of myocardial invasion with rupture of the aortic root into the pericardial space and extension of infection into the right atrium. We reviewed 48 other cases of infective endocarditis caused by H. parainfluenzae reported since 1970. There was only one report of extensive tissue invasion adjacent to the site of valve infection.5 That patient had aortic valve endocarditis with destruction of the valve leaflets and suppuration in the interventricular septum. After surgery he developed a ventricular septal defect and died as a result of pneumonia 3 weeks later. In conclusion, extensive perivalvular tissue destruction and myocardial abscess formation may occur with infective endocarditis caused by H. parainfluenzae. These complications should be considered when there is clinical deterioration with heart failure or when abnormalities of the conduction system occur as with other more invasive pathogens.

Long-term Durability of the Hancock Porcine Bioprosthesis Following Combined Mitral and Aortic Valve Replacement: An 11-Year Experience

Long-term evaluation of patients undergoing combined mitral and aortic valve replacement (MVR + AVR) with a porcine bioprosthesis provides the opportunity for a direct comparison of the durability of the mitral versus the aortic porcine bioprosthesis in the same patient. From 1970 to 1983, 71 patients underwent MVR + AVR with Hancock porcine bioprostheses. There were 46 men an 25 women ranging in age from 21 to 64 years (mean, 47.5 ± 5 years). Sixteen patients (22.5%) died at operation. The survivors were followed from 0.2 to 11.5 years (mean, 5.7 ± 3 years). Duration of follow-up was 313 patient-years and was 100% complete. Overall late mortality was 6.7 ± 1.4% per patient-year (linearized incidence), and actuarial survival was 54.2 ± 8% at 11 years. Endocarditis occurred in 4 patients (linearized incidence of 1.3 ± 0.6% per patient-year); thromboembolic events were sustained by 4 patients (linearized incidence of 1.3 ± 0.6% per patient-year); the event was fatal in 1 patient. Actuarial freedom from thromboembolism was 90 ± 4.8% at 11 years. Reoperation for primary tissue failure was performed in 11 patients (linearized incidence of 3.5 ± 1% per patient-year) with no deaths; in 7 patients both bioprostheses were explanted, and in 4, only the mitral bioprosthesis was replaced. The durability of explanted aortic and mitral porcine bioprostheses was not significantly different, and the evaluation of seven pairs of explanted aortic and mitral bioprostheses showed similar amounts of calcification. Actuarial freedom from reoperation because of primary tissue failure was 44.6 ± 13.7% at 11 years. Our experience indicates that (1) reoperation for primary tissue failure can be performed with low operative risk in patients who underwent MVR + AVR with porcine bioprostheses and (2) the durability of aortic and mitral porcine bioprostheses implanted in the same patient is similar.

Performance of a fabricated trileaflet porcine bioprosthesis: Midterm follow-up of the Hancock modified-orifice valve

The fabrication of the Hancock modified-orifice valve raised questions about its long-term durability. Since 1976, 315 patients (206 male, 109 female) with a mean age of 63 years underwent aortic valve replacement with 21 mm (n = 120), 23 mm (n = 153), 25 mm (n = 36), and 27 mm (n = 6) Hancock modified-orifice valves. There were five operative deaths (1.6% mortality). Two hundred sixty-two patients are alive 2 to 117 (mean 53) months postoperatively. Actuarial probability of survival at 96 months was 78% +/- 3%. Two hundred twenty-two survivors are in Functional Class I or II. Forty-three patients have had valve-related complications: thromboembolism in 25 (1.9%/pt-yr), primary valve dysfunction in eight (0.6%/pt-yr), and endocarditis in 11 (0.8%/pt-yr). Twelve patients have required reoperation (0.8%/pt-yr) for primary valve dysfunction (four patients), for endocarditis (five patients), and for perivalvular leak (three patients). At 96 months the actuarial probability of freedom from thromboembolism was 87% +/- 3%, from primary valve dysfunction 97% +/- 2%, and from endocarditis 92% +/- 3%. The probability of freedom from all valve-related complications was 78% +/- 4% and from reoperation 94% +/- 2%. The performance of this prosthesis justifies its continued use for aortic valve replacement.

Comparative Clinical Experience with Porcine Bioprosthetic and St. Jude Valve Replacement

From 1976 to 1984, 656 patients underwent aortic, mitral, or double valve replacement with a Hancock or Carpentier-Edwards porcine bioprosthesis (POR; n = 293) or with a St. Jude bileaflet valve (SJ; n = 363). Recipients of the St. Jude valve were of more advanced NYHA class preoperatively, required smaller prosthetic sizes, and more often had associated coronary artery disease necessitating bypass grafting (p less than .05). Despite these differences, POR and SJ recipients demonstrated similar 30-day mortality (7.5 vs 10.2 percent), five-year freedom from embolism (92 +/- 2 percent vs 92 +/- 2 percent), freedom from all valve-related complications (79 +/- 3 percent vs 79 +/- 4 percent), and survival (72 +/- 3 percent vs 71 +/- 3 percent) (p = NS). Structural failures occurred exclusively in POR recipients (3.0-4.5 percent/pt-yr after four years), and endocarditis was more common (1.0 vs 0.5 percent/pt-yr); as a result, the reoperation rate was three times higher in POR than SJ recipients (1.4 vs 0.46 percent/pt-yr, p less than .05). Warfarin-related bleeding (2.5 percent/pt-yr) was the most common complication in SJ recipients, but occurred equally frequently in POR recipients requiring anticoagulation; seven (44 percent) of 16 valve-related late deaths were warfarin-related. In properly anticoagulated patients, the thromboembolic rate was low (2.0 percent and 1.1 percent/pt-yr, POR and SJ); this rate increased significantly in SJ recipients receiving antiplatelet drugs alone (4.2 percent/pt-yr; n = 16) or no anticoagulant or antiplatelet therapy (26.4 percent/pt-yr; n = 18) (p less than .05), but increased only slightly in POR recipients (to 1.5 percent/pt-yr, n = 108, and 2.0 percent/pt-yr, n = 63, respectively). Postoperatively, NYHA class 1 was more often achieved in SJ than POR recipients (60 vs 39 percent, p less than .05), perhaps because of the better hemodynamic performance of the SJ valve. Thus, despite differences in patient selection and the nature of complications observed with each prosthetic type, porcine and St. Jude valves provide similar early and late survival, frequency of embolism, total complication rate, and freedom from valve-related morbidity and mortality after five years of follow-up. Limited durability, susceptibility to infection, and inferior hemodynamics remain drawbacks to use of the porcine bioprosthesis. The necessity for warfarin anticoagulation and the frequency of resultant bleeding complications are the major shortcomings of the St. Jude valve.(ABSTRACT TRUNCATED AT 400 WORDS)

Hemodynamic evaluation of porcine bioprostheses in the mitral position by doppler echocardiography

Twenty-four patients with porcine bioprostheses in the mitral position were studied by Doppler echocardiography followed by cardiac catheterization within 24 hours. Doppler mean diastolic mitral valve gradient was calculated by a 3-point method and mitral valve area was determined by the pressure half-time method. Data from Doppler echocardiography and cardiac catheterization were compared. There was a strong correlation between Doppler echocardiography and catheterization-determined mean diastolic gradient: r = 0.9, standard error of estimate (SEE) = 1.4 mm/Hg (regression equation y = 0.63x + 1.41), p <0.001. There was also a strong correlation between Doppler echocardiography and catheterization-determined mitral valve area: r = 0.86, SEE = 0.18 cm 2 (regression equation y = 0.64x + 0.52), p <0.001. Fourteen patients whose valvular function was considered normal by clinical evaluation had Doppler-calculated mean diastolic gradients of 4.5 to 9.5 mm Hg (mean 6.5 ± 1.4); the Doppler-determined valve area was 1.15 to 2.0 cm 2 (mean 1.54 ± 0.3). Ten patients had a malfunctioning bioprosthesis, 7 had severe mitral regurgitation and 3 had stenosis. Valvular malfunction in all 10 patients was detected by Doppler echocardiography and confirmed by catheterization and angiocardiography. Nine patients underwent reoperation. Doppler hemodynamic evaluation of porcine bioprostheses in the mitral position provided noninvasive information comparable to that obtained by cardiac catheterization.

Accurate Patient Diagnosis of Acute Porcine Valve Failure

Spontaneous porcine bioprosthetic valve failure is usually of gradual onset. We report a case of acute porcine mitral valve rupture resulting in rapid hemodynamic decompensation. The patient perceived the moment of valvular failure as the abrupt onset of a vibrating sensation in his chest. As the number of patients with porcine bioprostheses continues to increase, acute valvular failure may become a more common clinical entity.

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.

Post bending of the polypropylene flexible stent in mitral Hancock bioprostheses.

The occurrence of stent post deformity was investigated in 38 consecutive, polypropylene flexible-stented Hancock porcine bioprostheses (PB) recovered from the mitral position because of early postoperative death or late tissue failure. The degree of deformity was assessed for each explant by calculating the triangular area obtained by projecting the apex of the stent posts on a plane and comparing it with the same area calculated for unimplanted PBs of comparable size. A significant stent deformity (reduction of the triangular area greater than 40%) was observed only in 6 PBs explanted because of tissue failure after a mean function time of 69.6 +/- 28 months. In these PBs, scanning electron microscopy of the bare surface of the stent at the point of maximal flexion showed cracks 0.7-1 microns large, which represent the morphological substrate of the so-called "creep" of polypropylene. Inward stent post bending may occur after implantation in mitral PBs and when severe, it corresponds to a definite ultrastructural plastic deformity of polypropylene.

Early thrombosis of a porcine bioprosthesis in the aortic valve position

Thrombosis of a porcine bioprosthesis in the aortic valve position is uncommon and usually occurs more than 1 year after implantation. 1 Only 3 patients with thrombosis of a porcine aortic valve bioprosthesis less than 1 year after insertion have been described. 2–4 We report life-threatening thrombosis of a Carpentier-Edwards porcine bioprosthesis in the aortic valve position 6 months postoperatively.

Primary Tissue Valve Degeneration in Glutaraldehyde-Preserved Porcine Bioprostheses: Hancock I Versus Carpentier-Edwards at 4- to 7-Years' Follow-up

In the 32-month period between April, 1978, and December, 1980, 292 patients, divided into two equal groups, received a glutaraldehyde porcine bioprosthesis—either Hancock or Carpentier-Edwards (CE)—as mitral valve substitute. Every patient receiving a mitral porcine xenograft during that time was included in the study. The type of bioprosthesis was always selected by the surgeon and not randomly. Preoperative clinical characteristics, associated surgical procedures, valve implantation sizes, and follow-up data showed no relevant differences between the two groups. There were three instances of primary tisue failure in the Hancock group and six in the CE (linearized rates of 0.49 and 0.97 events percentage of patient/years, respectively). Mean duration of explanted valves and microscopic findings were similar in both groups. Primary tissue failure was more frequent in patients under 40 years of age in both groups, although differences were not statistically significant. A marginally significant trend toward greater incidence of tissue failure in patients of 40 years of age and older was seen in the CE group when compared with the Hancock group. Actuarial survival of the bioprostheses free from primary tissue failure was 6.5 years of 95 ± 3% (mean ± standard error) for Hancock and 84 ± 9% for CE ( p = NS). No significant difference in terms of durability has been found between the two most popular glutaraldehyde porcine bioprostheses, although the behavior of the CE in patients older than 40 years should be reassessed in a study with a larger number of patients and a longer follow-up period.

In vitro hemodynamic characteristics of tissue bioprostheses in the aortic position

The in vitro hemodynamic characteristics of a variety of old and new generation porcine and bovine pericardial bioprostheses were investigated in the aortic position under pulsatile flow conditions. The following valves were studied: Carpentier-Edwards porcine (Models 2625 and 2650), Carpentier-Edwards pericardial, Hancock porcine (Models 242, 250, and 410), Hancock pericardial, and Ionescu-Shiley (standard and low-profile) bioprostheses. The pressure drop results indicated that the old design valves had performance indices in the range of 0.30 to 0.42, whereas the new low-pressure fixed designs have performance indices of 0.50 to 0.70. Flow visualization and velocity and turbulent shear stress measurements, conducted with a two-dimensional laser Doppler anemometer system, indicated that all tissue valve designs created jet-type flow fields. The intensity of the jets and turbulence levels were less severe with the new designs. The old designs created higher peak jet velocities and higher levels of turbulent shear stresses. On the whole, pericardial bioprostheses have better in vitro hemodynamic characteristics than porcine bioprostheses. These observations should have applications regarding the clinical choice of bioprosthetic valves and have implications regarding further improvements in the preparation and design of bioprosthetic valves.

Percutaneous balloon valvuloplasty for stenosis of a porcine bioprosthesis in the tricuspid valve position

Recently, percutaneous balloon dilatation has been successfully used for treatment of congenital aortic and pulmonary valvular stenoses. 1 We report the first case of percutaneous valvuloplasty of a severely stenosed porcine bioprosthetic valve.

Experiences with 1643 porcine prosthetic valves in 1492 patients.

Sixteen hundred and forty-three porcine prosthetic values (1102 Carpentier-Edwards, 541 Hancock) were implanted in 1492 patients at New York University Medical Center between January 1976 and June 1983. The aortic valve alone was replaced in 786 patients (53%), mitral valve alone in 556 (37%), and multiple valves in 143 patients (9.6%). Concomitant coronary artery bypass was performed in 326 patients (22%). There were 116 deaths within 30 days of operation (7.8%). Follow-up (mean: 42 months) was completed in 94% of survivors and revealed that late survival from cardiac-related death was 87% at 5 years and 81% at 7 years, with no significant difference between the Carpentier-Edwards and Hancock patients. Late thromboembolic complications, however, were significantly more frequent in Hancock patients at all intervals from 1-7 years (p less than 0.05), whether in the aortic or mitral position. Patients with coronary artery disease who had concomitant coronary bypass showed a survival from late cardiac death that did not differ significantly from that of patients undergoing valve replacement alone. Before operation, 87% of patients were in New York Heart Association Class III or IV, but after operation 80% were in Class I or II. Late anticoagulant complications, endocarditis, and valve dysfunction were relatively rare. These results from a series of such size, duration, and representative numbers of two types of porcine bioprosthesis confirm excellent results with porcine prostheses in the first 4-5 years following operation.