Thromboembolism in patients with aortic porcine bioprostheses

Thromboembolism was prospectively studied in 215 patients who survived aortic valve replacement with porcine bioprostheses. All patients were anticoagulated with warfarin sodium during the first 3 postoperative months. Thereafter, 80 patients received aspirin (325 or 650 mg per day) and 135 received no antiplatelet or anticoagulant drugs. The two groups of patients were similar. Thromboembolic complications were carefully searched for during the follow-up interviews. Patients were removed from the study after a thromboembolic event unless there was no change in their management. The follow-up ranged from 6 to 80 months (mean, 36 months). The linearized thromboembolic rate in patients on a regimen of aspirin was 1.3% per patient-year and in patients not taking aspirin, 5.2% per patient-year (p less than 0.02). Replacement of the ascending aorta and patch enlargement of the aortic annulus with a Teflon graft were identified as significant risk factors for thromboembolism in patients with aortic porcine bioprostheses. These findings indicate that patients with aortic porcine bioprostheses should receive aspirin, especially if they also had replacement of the ascending aorta or patch enlargement of the aortic annulus with a Teflon graft.     

Mitral valve replacement with Hancock porcine bioprostheses: up to 7-year follow-up

From February 1976 to May 1981 at the University of Ottawa Heart Institute, 137 mitral valves were replaced with the Hancock porcine bioprosthesis. This study concerns 111 patients (55 men, 56 women) who had single-valve replacement. The average age of the patients was 53.0 years. The predominant lesion in the 102 patients who were receiving their first substitute valve was stenosis in 46% and regurgitation in 42%. Preoperatively, 82% were New York Heart Association (NYHA) class III or IV. Additional procedures were performed in 44 patients (39.6%). The 26 patients who had multiple valves replaced were considered only for durability studies. Hospital mortality was 8.9% for isolated replacement and 22% for replacement associated with aortocoronary bypass grafting. At the time of discharge, 50% of patients were in atrial fibrillation, 14% were taking warfarin and 82% antiplatelet agents. Follow-up was available for a total of 374 patient-years (average of 5.4 years per patient). The mean symptomatic improvement was 1.6 NYHA classes per patient. Actuarial analysis indicated a survival rate of 70% at 8 years. Of the 18 late deaths, 4 (22%) were valve-related. The rates of endocarditis and thromboembolism were 1.1% and 5.8% patient-year respectively. In the 137 prostheses at risk, intrinsic failure occurred at the rate of 4.7% patient-year for a cumulative rate of 35% at 8 years. The authors conclude that the Hancock porcine bioprosthesis provides good relief of symptoms in the mitral position with an acceptable rate of thromboembolism even without anticoagulation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical results with the Biocor porcine bioprosthesis.

In order to evaluate our clinical results with the use of the Biocor prosthesis, a total of 1,101 patients were studied. Follow-up was from 1 to 96 months (mean 48); cumulative follow-up in the aortic group (385 patients) was 1,230 patient years and in the mitral group (716 patients) 3,018 patient years. Mitral patients had 102 late complications (14.24%), and aortic patients had 51 (13.2%). A total of 220 patients were under 20 years of age (176 mitral, 44 aortic). Intrinsic valve failure in this subgroup was found in 43% of mitral patients and 29% of aortic patients. Prosthetic endocarditis was more frequent in the aortic group (45%) than in the mitral group (29.9%). Sixty-two patients were reoperated, with a hospital mortality of 12.6%. Reoperation was more frequent in the mitral group and in patients under 20 years of age. The actuarial curve free mortality related to the bioprosthesis was 97.1% (32 patients). At the 8-year follow-up, 96.9% of the aortic versus 95.2% of the mitral group were free of valve dysfunction, and the majority were in Classes I or II of the New York Heart Association (NYHA) classification. The incidence of reoperation, although significant, is acceptable, especially since the bioprosthesis offers a safer alternative than mechanical prostheses followed for similar periods. Analysis of our results suggests the need for continued research for an ideal bioprosthesis.     

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

BACKGROUND: We analyzed the intermediate experience, survival, and prosthetic complications of patients who received the Biocor valve, a new-generation porcine valve, in the mitral position. METHODS: At the University of Padua, between May 1992 and January 2004, 154 consecutive patients (102 female and 52 male patients; mean age, 72.3 +/- 6 years; age range, 37-86 years) received 158 mitral Biocor prostheses (Biocor Industria e Pesguisa Ltda, Belo Horizonte, Brazil). Thirty-five percent of the patients had previous mitral operations, 24% had coronary artery bypass grafting, and 34.6% had other procedures. Median preoperative New York Heart Association class was III. Echocardiography was performed in 75% of the long-term survivors. Follow-up included 609.4 patient-years and was 100% complete, with a median time of 4 patient-years (range, 0.02-11.3 years). At 8 years, 20 (14%) of 142 operative survivors were still at risk. RESULTS: Early mortality was 13.6%. According to univariate analysis, New York Heart Association class III to IV, ejection fraction of less than 40%, urgency, male sex, and coronary artery bypass grafting were significant perioperative risk factors. Eight- and 10-year actuarial survival was 51.1% +/- 5.6% (40 deaths). Eight-year actuarial freedom from valve-related death, thromboembolism, anticoagulant-related hemorrhage, endocarditis, paravalvular leak, and valve-related complications were 85.2% +/- 5%, 85.7% +/- 4.4%, 92.6% +/- 3.7%, 94.1% +/- 3%, 91.8% +/- 3%, and 70.2% +/- 5.7%, respectively. Freedom from structural valve deterioration was 100%. Actual freedom from reoperation was 93.2% +/- 2.2%. By Doppler echocardiography, the peak and mean transprosthetic gradients were 15 +/- 5 mm Hg and 6.3 +/- 3 mm Hg, respectively (mean follow-up, 4.2 +/- 2.7 years). CONCLUSION: At intermediate follow-up, the Biocor prosthesis in the mitral position showed excellent results in terms of valve durability when compared with other second-generation tissue valves.     

Leaflet geometry and function in porcine bioprostheses

The leaflet geometry and hydrodynamic function of five porcine bioprostheses have been studied and compared to a fresh tissue porcine valve. The neutral leaflet geometries in two high pressure fixed valves (Carpentier Edwards and Hancock) and two low pressure fixed valves (Carpentier Edwards Supra-Annular and Hancock 2) had been modified during fixation and mounting. The leaflets were extended or displaced downwards towards the base of the valve, producing a higher ratio of circumferential leaflet length to inter-commissural spacing than in the fresh tissue valve. This produced high bending strains in the commissural area of the open leaflet in hydrodynamic tests. The leaflet geometry of the fresh tissue porcine valve studied was defined by a cylindrical shell inclined at approximately 27 degrees to the base of the valve and showed reduced open leaflet bending strains. Leaflet opening at low flows was dependent on leaflet geometry. Geometrical changes which are induced during mounting and fixation produced higher bending strains in the commissural area of the open leaflets. These may be contributing factors to tissue degeneration and calcification in this area.     

Catastrophic thrombosis of porcine aortic bioprostheses

Hemodynamically critical thrombotic stenosis of porcine bioprosthetic valves in the aortic position without thrombotic predisposition is rare. Two patients at our institution abruptly manifested thrombotic stenosis of porcine bioprosthetic valves in the aortic position within 3 months of implantation without apparent predisposing factors. Clinicians should consider this rare but catastrophic complication in the appropriate setting.     

广东I型生物瓣行二尖瓣单瓣置换166例(长期随访报告)

目的　探讨生物瓣二尖瓣单瓣置换后的远期疗效。方法　 16 6例使用广东I型猪瓣(GD I)行风湿性二尖瓣病变单瓣置换病人中男 79例 ,女 87例 ;平均年龄 (2 9 4± 9 9)岁。按年龄分为第1组 (<30岁 ) 84例 ,第 2组 (≥ 30岁 ) 82例。 76 3 %的病人为房颤心律 ,6例术前有脑梗塞病史 ,98%的病人术前心功能为NYHAIII～IV级。结果　 14年累计生存率 (5 2 5± 7 0 ) %。术后 90 %心功能恢复至I～II级。晚期 89例出现瓣衰坏 ,5 9例再手术 ,13年累计瓣膜未衰坏率为 (15 5± 4 3) % ,其中第 2组衰坏率较低。衰坏瓣膜病理改变为严重瓣膜钙化并瓣叶撕裂 ,右冠瓣病变较重。 7例感染性心内膜炎 ,1例脑梗塞。结论　GD I猪瓣能有效治疗风湿性二尖瓣病变 ,改善病人心功能。病例选择应为老年病人。生物瓣膜衰坏率较高 ,制作工艺有待改进。术后感染性心内膜炎应予以足够重视。     

Long-term performance of porcine heart valve bioprostheses

To assess the results after long-term implantation of porcine bioprosthetic heart valves, 320 patients with 381 valves were retrospectively reviewed. This group included all patients receiving one such xenograft in the mitral or aortic position (or both) in our institution between June 1974 and December 1976. The patients had a follow-up of 9-11.5 years. Actuarial patient survival rats (hospital mortality excluded) were 85%-90% at 6 years and 68%-79% at 11.5 years. Thromboembolic episodes did not show any significant clustering over the first weeks or months, in fact, they appeared at a constant rate. Actuarial rates of freedom from thromboembolism were greater than 90% for aortic patients at 11.5 years and greater than 80% for mitral and mitroaortic patients at 11.5 years. The linearized rate of anticoagulant-related haemorrhage for the whole group of patients was 0.4 events/100 patient years with a related mortality of 0.2 events/100 patient years. Prosthetic valve endocarditis and paravalvular leak appeared at linearized rates of 0.6 (0.1 of related mortality) and 0.4 (0.1 of related mortality) events/100 patient years. Primary tissue valve failure constituted the most prevalent complication (82 cases) in the long term but did not significantly worsen patient survival. Actuarial rates of freedom from primary tissue failure were 91% +/- 2% at 6, and 40% +/- 14% at 11.5 years for mitral valves, and 95% +/- 4% at 6 and 64% +/- 6% at 11.5 years for aortic valves.(ABSTRACT TRUNCATED AT 250 WORDS)     

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

BACKGROUND: Bioprosthetic valve use represents a crucial improvement in surgical treatment of mitral valve disease. The aim of this study is to determine the long-term durability of the Biocor porcine bioprosthetic mitral valve. METHODS: Between 1985 and 1989, a total of 158 Biocor porcine bioprosthetic valves were placed in the mitral position, and long-term results of these patients were investigated retrospectively in 1999. RESULTS: Thirty-day mortality was 4.4% (7 patients). Total follow-up was 1,499 patient-years. Actuarial survival was 83.66% +/- 3% at 5 years, 77.78% +/- 3.36% at 13 years (1.8% patient-year). Multivariate analysis demonstrated younger age, duration of implantation, congestive heart failure, and functional class to be significant predictors of late mortality. Actuarial freedom from valve-related mortality was 98.58% +/- 1% at 15 years (0.13% patient-year). Actuarial freedom from structural valve deterioration was 95.49% +/- 1.8% at 5 years, 70.2% +/- 4.12% at 10 years, and 64.82% +/- 5.34% at 13 years (2.6% patient-year). Actuarial freedom from structural valve deterioration-related reoperation was 98.43% +/- 1.1% at 5 years, 89.15% +/- 2.85% at 10 years, and 76.82% +/- 7.91% at 14 years. Multivariate analysis showed younger age and duration of implantation to be significant predictors of structural valve deterioration and its related reoperation. CONCLUSIONS: By studying a 15-year time period, it is seen that this new generation porcine bioprosthetic valve should be considered an alternative for mechanical valves in selected patients.     

Calcification resistance with aluminum-ethanol treated porcine aortic valve bioprostheses in juvenile sheep

BACKGROUND: Calcification of glutaraldehyde fixed bioprosthetic heart valve replacements frequently leads to the clinical failure of these devices. Previous research by our group has demonstrated that ethanol pretreatment prevents bioprosthetic cusp calcification, but not aortic wall calcification. We have also shown that aluminum chloride pretreatment prevents bioprosthetic aortic wall calcification. This study evaluated the combined use of aluminum and ethanol to prevent both bioprosthetic porcine aortic valve cusp and aortic wall calcification in rat subcutaneous implants, and the juvenile sheep mitral valve replacement model. METHODS: Glutaraldehyde fixed cusps and aortic wall samples were pretreated sequentially first with aluminum chloride (AlCl3) followed by ethanol pretreatment. These samples were then implanted subdermally in rats with explants at 21 and 63 days. Stent mounted bioprostheses were prepared either sequentially as previously described or differentially with AlCl3 exposure restricted to the aortic wall followed by ethanol pretreatment. Mitral valve replacements were carried out in juvenile sheep with elective retrievals at 90 days. RESULTS: Rat subdermal explants demonstrated that sequential exposure to AlCl3 and ethanol completely inhibited bioprosthetic cusp and aortic wall calcification compared with controls. However the sheep results were markedly different. The differential sheep explant group exhibited very low levels of cusp and wall calcium. The glutaraldehyde group exhibited little cusp calcification, but prominent aortic wall calcification. All sheep in the two groups previously described lived to term without evidence of valvular dysfunction. In contrast, animals in the sequential group exhibited increased levels of cusp calcification. None of the animals in this group survived to term. Pathologic analysis of the valves in the sequential group determined that valve failure was caused by calcification and stenosis of the aortic cusps. CONCLUSIONS: The results clearly demonstrate that a combination of aluminum and ethanol reduced aortic wall calcification and prevented cuspal calcification. Furthermore, this study demonstrates that exclusion of aluminum from the cusp eliminated the cuspal calcification seen when aluminum and ethanol treatments were administered in a sequential manner.     

Long-term results of porcine bioprostheses in the tricuspid position

(Received for publication on Feb. 10, 1997; accepted on Sept. 2, 1997)     

Late tears in leaflets of porcine bioprostheses in adults

Of 836 patients with a mitral or aortic bioprosthesis who were followed over an 8-year period, 32 required reoperation for prosthetic dysfunction. Of the 26 prostheses removed at operation, 18 (12 mitral and 6 aortic prostheses) showed tears in the valve leaflets. In 7 of the 12 patients with rupture of "mitral" leaflets and in 1 of the 6 patients with torn "aortic" leaflets, the onset of symptoms was sudden, requiring urgent reoperation. Two of the 18 patients died early after reoperation; both had progressive disability and underwent elective operation. In 5 of the 7 patients with torn leaflets in a mitral prosthesis who had acute onset of symptoms, a single tear was found and no gross evidence of calcification was detected. Macroscopic calcification was found in only 8 of the 18 (44.4%) prostheses with torn leaflets (mitral and aortic). Microscopic examination revealed calcific deposits in 9 of the 12 mitral and in all of the aortic bioprostheses. Of the 54 leaflets examined, 29 had tears: 10 were type I; 6, type II; 7, type III; and 6, type IV. Tears in porcine valve leaflets are not an uncommon cause of dysfunction. These tears often lead to acute hemodynamic changes, particularly in the mitral position, and usually require emergency reoperation. They may occur in prostheses that appear grossly normal.     

Tricuspid dura mater bioprostheses: more than 20-year follow-up of 3 patients

Replacement of the tricuspid valve is sometimes necessary. We report 3 consecutive patients with tricuspid insufficiency who underwent valve replacement with glycerol-preserved, homologous dura mater cardiac bioprostheses between 1971 and 1973. The first 2 patients are well 28 and 27 years later; the last patient was lost to follow-up after 20 years. We conclude that preservation of homologous dura mater bioprostheses in glycerol may reduce rates of thromboembolism, thrombosis, and structural dysfunction during the late postoperative period.     

Long-term results of porcine bioprostheses in the tricuspid position.

Between 1974 and 1990, 58 patients underwent tricuspid valve replacement with porcine bioprostheses (Hancock 42, Carpentier-Edwards 16) during multiple valve replacement (double, 21; triple, 37). Perioperative mortality was 12%; 16 patients died later, mostly from cardiac causes. Actuarial survival (1 patient lost to follow-up) was 81% +/- 11% at 5 years, and 60 +/- 17% at 10 years. Reoperation because of Hancock prosthesis deterioration was performed in 2 patients at 11 and 15 years, respectively. At last follow-up (mean 108 +/- 48 months), 82% of survivors (28/34) were functionally improved. Doppler echocardiography was performed in 29 patients in February 1991. In 21 patients, after 88 +/- 40 months of follow-up, the bioprosthesis was normal, there was no leaflet malformation, no significant tricuspid regurgitation and the mean diastolic transprosthetic gradient (DTPG) was 3.8 +/- 1.7 mmHg. In 7 patients (follow-up: 129 +/- 40 months, P less than 0.05), there was moderate dysfunction (all Hancock prostheses) with leaflet sclerosis, tricuspid regurgitation grade 2, and mean DTPG 5.7 +/- 1.8 mmHg (P less than 0.05). Only 1 patient (Hancock prosthesis implanted in 1981) had severe tricuspid prosthesis stenosis with very thickened leaflets and mean DTPG 13 mmHg. Pulmonary artery hypertension (most often fixed) was present in 11 patients, associated with a poor functional result and a significantly higher DTPG. We conclude that porcine bioprostheses in tricuspid position have an acceptable long-term durability and satisfactory performance. Prosthetic dysfunction correlates with the length of follow-up of patients and with the presence of fixed pulmonary artery hypertension.     

全膝关节置换术治疗合并帕金森病骨关节炎患者的中期随访和临床疗效分析

目的 :探讨全膝关节置换术治疗伴有帕金森病的膝关节骨关节炎的患者的中期随访的临床疗效及经验总结。方法:收集自2011年1月至2014年1月收治19例(21膝)全膝关节置换术治疗帕金森合并膝关节骨性关节炎的患者,其中男9例,女10例;年龄61~83岁,平均71.3岁,术前及术后查影像学结果,评估影像学表现。采用VAS疼痛评分及膝关节评分系统KSS评价临床效果。术前对患者进行帕金森病Hoehn-Yahr分级:1期3例,1.5期4例,2期5例,2.5期4例,3期2例,4期1例。结果:19例患者获得随访,时间3~7年,平均4.3年。患者疼痛均较术前明显减轻或消失。所有患者切口Ⅰ期愈合。末次随访时,3例有膝前疼痛,其中轻度疼痛1例,中度2例,无重度疼痛。患者VAS评分由术前的8.4±1.3降低到末次随访时的3.1±1.2(P0.05)。KSS评分由术前的43.6±7.3提高到末次随访时的91.8±10.6(P0.05)。帕金森病情在药物控制下进展不明显。X线检查未见假体松动及下沉断裂。结论:人工全膝关节置换术在帕金森病人中的应用是一种安全有效的方法。中期随访疗效较满意。     

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 tissue 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.     

Late pathological changes of Carpentier-Edwards porcine bioprostheses in the mitral position

Eighty-nine patients received mitral valve replacement with Carpentier-Edwards porcine bioprostheses between 1975 and 1983. Eighty-three patients (93.3%) were followed up after the operation; early death (within one month of operation) occurred in 6 patients and late death in 2 patients. After the operation, 64 survivors (85.3%), who did not require reoperation, exhibited improved symptoms according to the NYHA functional class. Of the 6 patients (6.7%) who required reoperation, 5 patients underwent reoperation 50 to 85 months after the implantation. Pathologically, all the removed valves showed degeneration of collagen and elastic fibers, no host endothelialization and mild to moderate infiltration of inflammatory cells. Thrombus in the left atrium was detected in one case. Destruction of the cusps was seen in three cases and calcification of the cusps developed in three cases. In general, the Carpentier-Edwards porcine bioprosthesis provided good clinical improvement over the periods studied. However, morphological changes of the bioprosthetic valve, such as destruction collagen and elastic fiber, and inflammatory cell infiltration of the cusps, seems to occur more frequently with the passage of time. We therefore suggest that patients with this prosthesis should be followed carefully, particularly at late intervals after implantation.     

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

BACKGROUND: Performance with regard to structural valve deterioration (SVD) with the Carpentier-Edwards standard (CE-S) and supraannular (CE-SAV) (Baxter Healthcare Corp, Irvine, CA) porcine bioprostheses was evaluated to determine whether progress in reduction of structural failure has been achieved with technological changes. METHODS: The CE-S was implanted during 567 aortic valve replacement (AVR) and 486 mitral valve replacement (MVR) procedures, and the CE-SAV was implanted during 1,670 AVR and 1,096 MVR procedures. The failure mode of early stent dehiscence with the CE-SAV prosthesis, thought to be controlled by manufacturing changes in 1986 and 1987, supported comparison of the CE-SAV with censored cases of stent dehiscence. Stent dehiscence accounted for only 1.2% (1 of 81) and 14.1% (29 of 205) of AVR and MVR CE-SAV failures, respectively. RESULTS: The only difference for AVR for freedom from SVD occurred in the 21- to 40-year age group at 15 years and was 68% for the CE-SAV and 31% for the CE-S (p<0.05). In the 61- to 70-year age group, freedom from SVD at 15 years was 76% for the CE-S and 84% for the CE-SAV; for the 71-year or higher age group, freedom from SVD was 89% and 95%, respectively (p = NS). For MVR freedom from SVD was different only in the 71-year or higher age group and was 90% for the CE-S and 59% for the CE-SAV (p<0.05). Freedom from SVD was reduced but was similar (p = NS) for the other age groups. For AVR the actual freedom from SVD at 15 years for the CE-S and CE-SAV was, respectively, 79% and 72% for the 51- to 60-year age group, 86% and 91% for the 61- to 70-year age group, and 98% and 98% for the 71-year or higher age group. For MVR, these rates were, respectively, 69% and 75% for the 61- to 70-year age group and 96% and 89% for the 71-year and higher age group. CONCLUSIONS: The technologic advancements made in the second-generation CE-SAV bioprosthesis to reduce the incidence of structural failure have not uniformly been successful. The actual freedom from SVD provides evidence for implantation of porcine bioprostheses for AVR in age groups 61 to 70 years and 71 years or higher and for MVR in the age group 71 years or higher.