Bioprosthesis Group Research Articles

Isolated pulmonary valve replacement: analysis of 27 years of experience

The aim of this study was to investigate the longterm results of isolated pulmonary valve replacement using xenobioprostheses or mechanical valves. Twenty-four cases of isolated pulmonary valve replacement carried out at Kyushu University Hospital between 1977 and 2004 were reviewed. Those undergoing Rastelli's operation were excluded from this study. Bioprostheses were used in 18 patients and mechanical valves in 6. There were no operative deaths. Two patients with mechanical valves needed repeat pulmonary valve replacement due to thrombosed valves. The patients with bioprostheses had no need of repeat replacement postoperatively. The cardiothoracic ratio significantly improved from 60.3% preoperatively to 55.4% postoperatively (P < 0.05), and the New York Heart Association (NYHA) class significantly improved from 2.0 preoperatively to 1.1 postoperatively (P < 0.05). The actuarial survival rate at 15 years was 92.3%. The valve-related event-free ratio at 15 years was 85.7% in the bioprosthesis group and 66.7% in the mechanical valve group, with no significant difference. Isolated pulmonary valve replacement with bioprostheses or mechanical valves can be safely done and showed satisfactory long-term results. The mechanical valve group demonstrated a high ratio of thrombosed valves. A bioprosthesis is recommended for pulmonary valve replacement if a homograft is not available.

Aortic Valve Replacement: Choice Between Mechanical Valves and Bioprostheses

The choice between a mechanical or bioprosthetic valve replacement device is not always clear, although patient age is most often the determining factor. We reviewed our experience with patients undergoing aortic valve replacement (AVR) in order to assess and compare long-term outcomes between patients receiving a mechanical valve and those receiving a bioprosthesis. Three hundred fifty-two patients underwent AVR with or without coronary artery bypass between 1993 and 2004: 189 received a mechanical valve and 163 a bioprosthesis. Events included: late mortality, thrombo-embolic events, stroke, bleeding events, valve thrombosis, endocarditis, reoperation, and coronary catheterization. Patients in the bioprosthesis group were older (71 +/- 11 vs. 65 +/- 13) than in the mechanical group (p < 0.0001). There was no difference in operative mortality (6.8%) or morbidity. Follow-up (61 +/- 40 months) was available in 87%. For mechanical valves and bioprostheses, respectively: 3-, 5-, and 10-year survival was 92%, 86%, and 69% versus 90%, 86%, and 71% (p = n.s.); and event-free survival was 79%, 68%, and 41% versus 79%, 68%, and 44% (p = n.s.). Five patients (3%) in each group required re-replacement of their aortic valve (p = n.s.). Coronary artery disease requiring bypass surgery did not affect long-term survival. Age at operation and renal failure were the only predictors for late mortality. Survival and event-free survival are similar for patients receiving a mechanical or biological aortic valve substitute. Selection of a valve replacement device should be based on life expectancy, patient preference, ability to take anticoagulants, lifestyle, risk of bleeding, and risk of reoperation. Patient age alone should not be the determining factor.

Valve Replacement Surgery in End-Stage Renal Failure: Mechanical Prostheses Versus Bioprostheses

The 1998 American College of Cardiology/American Heart Association Guidelines recommend mechanical prostheses for valve replacement in patients with end-stage renal disease requiring dialysis. The aim of the study is to evaluate the combined experience at two academic centers. Sixty-nine valve replacements (aortic 40; mitral 22; multiple 7; 47 bioprostheses, 22 mechanical prostheses) were performed. Total follow-up was 128.7 patient-years (bioprostheses, 68.4; mechanical prostheses, 60.4). Patient populations were homogeneous, except for age (bioprostheses greater than mechanical prostheses, p = 0.012), previous myocardial infarction (bioprostheses greater than mechanical prostheses, p = 0.040), and concomitant CABG (bioprostheses greater than mechanical prostheses, p = 0.019). A survival advantage was observed in favor of mechanical prostheses (p = 0.0299) at 5 years. Freedom from valve-related complications at 5 years was calculated for thromboembolism plus thrombosis plus hemorrhage (bioprostheses, 93.0% +/- 3.9%; mechanical prostheses, 76.4% +/- 12.7%), thromboembolism excluding thrombosis (bioprostheses, 93.0% +/- 3.9%; mechanical prostheses, 88.9% +/- 10.5%), and hemorrhage (bioprostheses, 100%; mechanical prostheses, 95.2% +/- 4.7%). One case of structural valve deterioration occurred in the bioprostheses group at 95 months after surgery. Five-year freedom from all valve-related complications was 82.8% +/- 8.1% for bioprostheses and 76.4% +/- 12.7% for mechanical prostheses. Overall survival was poor. Differences between populations were related to age at operation and coronary artery disease. Structural valve deterioration was not accentuated with bioprostheses. Considering lack of homogeneity between prostheses groups there was no superiority of mechanical prostheses over bioprostheses in terms of freedom from composites of complications. Bioprostheses should be considered in the management of valvular disease in end-state renal disease patients.

Platelet activation after aortic prosthetic valve surgery

Platelet activation, which may lead to thrombus formation, is poorly understood after valve surgery when analysed by flow cytometry. It is still unclear whether platelet activation is due to the implanted prosthesis itself or to its aortic or mitral position. The present prospective study was aimed at assessing platelet P-selectin expression, platelet-leukocyte conjugate formation and platelet microparticles and comparing biological, bileaflet and tilting disc valvular prostheses in aortic position. Thirty-three patients were included (15 bioprostheses, 11 bileaflet and 7 tilting disc mechanical valves). Blood samples were analyzed by flow cytometry immediately before surgery, on postoperative day 8 (D8) and 2 months after surgery (M2). At D8, patients with bileaflet valves demonstrated a significant increase in platelet-leukocyte conjugates and in platelet microparticles whereas only platelet-monocyte conjugates were significantly increased in patients with bioprostheses. At M2, platelet activation had returned to the basic level observed prior to surgery in the bileaflet valve group whereas, it was still increased in the bioprosthesis group. Neither at D8 nor at M2 did patients with tilting disc mechanical valves demonstrate any platelet activation. Platelet activation after aortic valve replacement was observed with the use of bioprostheses and bileaflet mechanical valves, but not with tilting disc mechanical valves.

Long-term follow-up of patients with mechanical prosthetic valves in the tricuspid position

It remains controversial whether biological or mechanical prostheses in the tricuspid position give better long-term results. The clinical advantage of mechanical prostheses is evaluated in this article. Our subjects were 25 consecutive patients who underwent tricuspid valve replacement (TVR) from January 1985. Five patients underwent TVR with mechanical prostheses (MP), and 20 patients had bioprostheses (BP). The mean age of the patients was 50.8 ± 15.9 years for those with MP and 50.2 ± 11.5 years old for those with BP. The preoperative New York Heart Association (NYHA) functional classification was 3.5 for those with MP and 3.1 for BP. The mean follow-up period was 5.05 ± 2.05 years for MP, ranging from 3 to 7 years, and 7.2 ± 5.6 years for BP, ranging from 1 to 12 years. No operative mortality occurred, but there was a single hospital death in a patient with BP due to sepsis after acute postoperative cholecystitis. One patient with BP suffered from neurological deficiencies. Long-term temporary cardiac pacing was required in one patient with MP and three with BP. A permanent cardiac pacemaker was implanted in one patient with BP. There was one late death in the MP group and three late deaths in the BP group. The actuarial survival rates at 5 and 7 years after surgery were 80% and 80%, respectively, for MP and 88% and 88% for BP. There was one embolic episode, a minor stroke, in the BP group. Four patients with BP had valvular dysfunction at 3, 8, 9, and 10 years after surgery, and two of these required re-TVR. Among BP patients, 93% were free from prostheses dysfunction at 5 years after surgery, and 78% were free from dysfunction after 10 years; all patients (100%) with MP were free from dysfunction at 7 years. This study suggests that TVR with MP shows no late complications and with careful anticoagulant therapy provides highly satisfactory follow-up results.

Late results of double-valve replacement with biologic or mechanical prostheses

Background. We previously showed that the risk of reoperation for structural degeneration of bioprostheses was higher in cases involving patients older than 65 years (p = 0.003) and double-valve replacement (p = 0.02). The purpose of this study was to compare late outcome of mitral-aortic valve replacement using bioprostheses or mechanical valves.Methods. The bioprosthesis group included all mainland France residents (n = 48) between 55 and 65 years old operated on between 1980 and 1995 for mitral-aortic valve replacement using bioprostheses. The mechanical valve group was obtained by matching each of these patients with a patient operated on using mechanical valves at approximately the same time during the study.Results. In the bioprosthesis group, 10-year survival was 45% ± 8% versus 62% ± 7% in the mechanical valve group (not significant). The linearized reoperation rate was 6.8 per patient-year versus 1.1 per patient-year (p = 0.001), and the linearized reoperative mortality rate was 1.8 per patient-year and 0.7 per patient-year (not significant), respectively.Conclusions. The reoperative mortality risk after mitral-aortic valve replacement using two bioprostheses does not significantly decrease overall survival after age 65 years.

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.

Comparison of porcine bioprostheses and mechanical prostheses in multiple valve replacement operations

The performance of porcine bioprostheses and mechanical prostheses in multiple valve replacement operations was evaluated in 494 patients with 553 operations between 1975 and 1992. Porcine bioprostheses were implanted in 351 multiple replacement operations and 202 operations were performed with mechanical prostheses. The mean age of the bioprosthesis group was 59.1 +/- 14.4 years and of the mechanical prostheses group, 55.9 +/- 13.3 years. Concomitant procedures, primarily coronary artery bypass grafting, were performed in 27.4% (96 patients) of the bioprosthesis group and 20.8% (42 patients) of the mechanical prosthesis group (p = not significant [NS]). The early mortality for the bioprosthesis group (BP) was 12.0% (42 patients), whereas for the mechanical prosthesis (MP) group it was 10.9% (22 patients) with no difference (p = NS) for the performance with or without concomitant procedures, primarily coronary artery bypass grafting. The total cumulative follow-up was 1,914 years for BP and 458 years for MP group. The late mortality was different between the groups (p < 0.05), 6.1%/patient-year for BP and 3.7%/patient-year for MP. The difference in late mortality was not different (p = NS) for performance of concomitant procedures and not different (p = NS) for the absence of concomitant procedures, 5.6%/patient-year for BP and 2.2%/patient-year for MP. The freedom from thromboembolism- and antithromboembolic-related hemorrhage favored the biological population (p < 0.05) at 10 years with 79.7% +/- 3.4% for BP and 75.4% +/- 5.0% for MP. The freedom from structural valve deterioration was 100% for MP, whereas for the BP group, 94.7% +/- 1.6% at 5 years and 65.9% +/- 4.3% at 10 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Perioperative events in patients with failed mechanical and bioprosthetic valves

From 1963 through 1991, 1037 patients underwent reoperative valvular procedures. The 478 patients having reoperations for either failed bioprosthetic (n = 212) or mechanical (n = 266) valves were evaluated. There were 210 male (44%) and 268 female (56%) patients. The mean age at reoperation of the patients in the bioprosthesis group was 59.7 years and and that in the mechanical valve group was 56.1 years (p = 0.0006). The mean interval to the time of reoperation was 84.7 months in the mechanical valve group and 74 months in the bioprosthesis group. There was no difference between the two groups in the functional class at reoperation. More severe mitral valve stenosis and incompetence, more severe aortic valve stenosis, and higher right ventricular and pulmonary arterial pressures were noted in the bioprosthesis group than in the mechanical valve group. Hemolysis (p = 0.05) was more prevalent in the patients with mechanical valves than in the ones with bioprostheses. A longer aortic occlusion time (p = 0.0001) and longer cardiopulmonary bypass time (p = 0.0001) were required for the reoperations in the bioprosthesis group. The operative mortality was 13.2% for the bioprosthesis patients and 12.4% for the mechanical valve patients. The risk factors for hospital death included the cross-clamp time (p = 0.0001), the functional class (p = 0.00001), the presence of ascites (p = 0.02), hepatomegaly (p = 0.002), and decreasing ejection fraction (p = 0.05). We conclude that mechanical valve failures do not produce catastrophic events resulting in poor reoperative results.

Aortic valve replacement with the Hancock standard, Björk-Shiley, and Lillehei-Kaster prostheses: A comparison based on follow-up from 1 to 15 years

Three series of patients undergoing isolated aortic valve replacement with the standard glutaraldehyde-preserved Hancock porcine bioprosthesis, the standard Björk-Shiley spherical disc prosthesis, and the Lillehei-Kaster tilting disc prosthesis were compared during a 15-year follow-up. From March 1970 to December 1985, aortic valve replacement was performed in 506 patients, 379 men and 109 women, whose ages ranged from 17 to 71 years (mean, 47 +/- 12 years); 196 had a Hancock bioprosthesis, 147 a Björk-Shiley prosthesis, and 163 a Lillehei-Kaster prosthesis. There were no significant differences among the three groups in terms of mean age, preoperative New York Heart Association class, valve lesion, associated intracardiac procedures, and operative mortality (11.7% for the Hancock bioprosthesis group, 8.8% for the Björk-Shiley prosthesis group, and 9.2% for the Lillehei-Kaster prosthesis group). Cumulative duration of follow-up is 1140 patient-years (mean, 6.6 +/- 1.5 years, 100% complete) for Hancock bioprosthesis patients, 878 patient-years (mean, 5.9 +/- 0.4 years, 98% complete) for Björk-Shiley prosthesis patients, and 1184 patient-years (mean, 7.3 +/- 0.3 years, 97% complete) for Lillehei-Kaster prosthesis patients. Actuarial survival rates at 15 years are 30% +/- 15% for Hancock bioprosthesis, 49% +/- 6% for Björk-Shiley prosthesis, and 44% +/- 7% for Lillehei-Kaster prosthesis patients. There were eight embolic episodes in Hancock valve recipients (0.7% +/- 0.1%/pt-yr), nine in Björk-Shiley prosthesis recipients (1.0% +/- 0.3%/pt-yr), and nine (0.7% +/- 0.1%/pt-yr) in Lillehei-Kaster prosthesis recipients (p = no significant difference). Actuarial freedom from emboli at 15 years is 89% +/- 4% for Hancock, 92% +/- 3% for Björk-Shiley, and 93% +/- 2% for Lillehei-Kaster prosthesis recipients (p = no significant difference). A significant difference was found in the incidence of the following complications. (1) Anticoagulant-related hemorrhage: 0.1% +/- 0.1%/pt-yr for Hancock bioprosthesis, 1.3% +/- 0.3%/pt-yr for Björk-Shiley prosthesis, and 1.9% +/- 0.4%/pt-yr for Lillehei-Kaster prosthesis patients (p less than 0.001), with an actuarial freedom at 15 years of 97.6% +/- 1% for Hancock, 85% +/- 5% for Björk-Shiley, and 68.8% +/- 10% for Lillehei-Kaster recipients (p less than 0.001). (2) Structural deterioration: 3.7% +/- 0.6%/pt-yr for Hancock and none for Björk-Shiley and Lillehei-Kaster patients (p less than 0.001), with an actuarial freedom of 100% for Björk-Shiley prosthesis and Lillehei-Kaster prosthesis patients and 38.4% +/- 12% for Hancock bioprosthesis patients at 15 years.

Late results after left-sided cardiac valve replacement in children

Selection of types of cardiac valve substitutes for children remains controversial. Between 1976 and 1984, 166 children, 15 years of age or younger, underwent aortic (N = 53) or mitral valve replacement (N = 90) or both (N = 23). Biological prostheses were used in 84 patients and mechanical prostheses in 71; both a mitral bioprosthesis and an aortic mechanical valve were used in 11 patients. The overall early mortality was 9%. Mean follow-up intervals were 4.1 years for the bioprosthesis group, 3.3 years for the mechanical valve group, and 3.5 years for the group receiving both. The 7 year survival rates (+/- standard error) were 63% +/- 6% in the bioprosthesis group and 70% +/- 7% in the mechanical valve group (p = NS). After aortic valve replacement the 7 year survival rates were 66% +/- 14% (bioprosthesis group) and 77% +/- 9% (mechanical valve group) (p = NS); after mitral valve replacement the rates were 65% +/- 7% (bioprosthesis group) and 54% +/- 17% (mechanical valve group) (p = NS). The incidence of thromboembolic events was 0.6% +/- 0.4% per patient-year in the bioprosthesis group (none after aortic valve replacement, 0.8% +/- 0.6% per patient-year after mitral valve replacement) and 1.4% +/- 0.8% per patient-year in the mechanical valve group (0.7% +/- 0.7% per patient-year after aortic valve replacement, 4.0% +/- 2.8% per patient-year after mitral valve replacement) (p = NS). The linearized rates of reoperation were 10.4% +/- 1.8% per patient-year (bioprosthesis group) and 2.3% +/- 1.0% per patient-year (mechanical valve group) (p less than 0.001). The 7 year probability rates of freedom from all valve-related complications were 43% +/- 6% in the bioprosthesis group and 86% +/- 4% in the mechanical valve group (p less than 0.001). In the aortic position, a mechanical adult-sized prosthesis can always be implanted, and satisfactory long-term results can be anticipated. In the systemic atrioventricular position, the results are less than satisfactory with either type of prosthesis; every effort should be made to preserve the natural valve of the child.