Doppler Sonographic Evaluation of the CarboMedics Bileaf let Valve Prosthesis: One-Year Experience

Between April 1989 and March 1991, 237 CarboMedics bileaflet valve prosthesis carriers (165 aortic and 72 mitral valves, mean age 54.4 years) were studied prospectively with pulsed- and continuous-wave Doppler at a mean interval of 11.4 months following surgery in order to establish ranges of normal flow velocities and pressure gradients. Physical examination revealed no signs of prosthetic dysfunction or heart failure. Postoperative left ventricular function as measured by fractional shortening was 37% for aortic valve carriers and 30% for mitral valve carriers (p = NS). Mean peak velocity (+/- SD) across the aortic valve was 2.6 m/sec (+/- 0.4) and calculated instantaneous peak pressure gradient ranged from 11 to 58 mmHg (mean 28.1 +/- 10.3). It has to be emphasized that occasional patients with normally functioning valve prostheses can show unusual high gradients. Ring diameters between 21 and 27 mm showed no significant difference with regard to flow velocities and pressure gradients, whereas in 19-mm valves, significantly higher values could be demonstrated. The 123 aortic valve carriers with normal left ventricular function (fractional shortening greater than 25%) showed significantly higher pressure gradients than the 19 patients with reduced left ventricular function (28.6 +/- 11.6 mmHg vs 16.2 +/- 5.1 mmHg, p less than 0.05). In the mitral position, the mean of peak velocity (+/- SD) was 1.7 +/- 0.4 m/sec and pressure half-time was 108 +/- 26 msec, representing a calculated valve area between 1.4 to 3.1 cm2 (mean orifice size 2.1 +/- 0.5 cm2). No significant difference between valves of different sizes was found.(ABSTRACT TRUNCATED AT 250 WORDS)     

Late incidence and determinants of reoperation in patients with prosthetic heart valves.

OBJECTIVES: Reoperation is a relatively common event in patients with prosthetic heart valves, but its actual occurrence can vary widely from one patient to another. With a focus on bioprosthetic valves, this study examines risk factors for reoperation in a large patient cohort. METHODS: Patients (N=3233) who underwent a total of 3633 operations for aortic (AVR) or mitral valve replacement (MVR) between 1970 and 2002 were prospectively followed (total 21,179 patient-years; mean 6.6+/-5.0 years; maximum 32.4 years). The incidence of prosthetic valve reoperation and the impact of patient- and valve-related variables were determined with actual and actuarial methods. RESULTS: Fifteen-year actual freedom from all-cause reoperation was 94.1% for aortic mechanical valves, 61.4% for aortic bioprosthetic valves, 94.8% for mitral mechanical valves, and 63.3% for mitral bioprosthetic valves. In both aortic and mitral positions, current bioprosthesis models had significantly better durability than discontinued bioprostheses (15-year reoperation odds-ratio 0.11+/-0.04; P<0.01 for aortic, and 0.42+/-0.14; P=0.009 for mitral). Current bioprostheses were significantly more durable in the aortic position than in the mitral position (14.3+/-6.8% more freedom from 15-year reoperation; (P=0.018)). Older age was protective, but smoking was an independent risk factor for reoperation after bioprosthetic AVR and MVR (hazard ratio for smoking 2.58 and 1.78, respectively). In patients with aortic bioprostheses, persistent left ventricular hypertrophy at follow-up and smaller prosthesis size predicted an increased incidence of reoperation, while this was not observed in patients with mitral bioprostheses. CONCLUSIONS: These analyses indicate that current bioprostheses have significantly better durability than discontinued bioprostheses, reveal a detrimental impact for smoking after AVR and MVR, and indicate an increased reoperation risk in patients with a small aortic bioprosthesis or with persistent left ventricular hypertrophy after AVR.     

Haemodynamic and echocardiographic characteristics of a stentless allograft mitral prosthesis: an in vitro study

Poor long-term durability and impaired haemodynamic performance are known disadvantages of bioprosthetic heart valves when compared to valve replacement using aortic allografts. A new stentless allograft mitral implant was developed and tested in vitro in a left ventricular model and pulsatile flow system to evaluate hydrodynamic function. Mitral valves were excised from sheep hearts and the mitral annulus reinforced by a strip of ovine pericardium. A patch of expanded polytetrafluoroethylene (ePTFE) was placed above the tips of the remaining papillary muscles. For in vitro evaluation of a total of five valves were investigated in a pulse duplicator. Transvalvular pressure gradients (ΔP) were measured over a flow range corresponding to a cardiac output of 51/min, at a heart rate of 70 beats/min, with a systole accounting for approximately 35% of the cardiac cycle. The systolic ejection period and diastolic filling period in this model were 350 and 510 ms, respectively, and aortic pressure was 120/80 mmHg. The effective orifice area was calculated from measurements of mean pressure drop and root mean square flow. Additionally, valve performance was evaluated by Doppler echocardiography. Results of in vitro studies of a 25 mm stentless allograft mitral implant, which is similar to the valves implanted in a chronic weanling sheep model, revealed a mean(s.d.) ΔP of 2.0(1.6) mmHg (range 1.0 – 4.9 mmHg). The mean calculated effective orifice area was 3.38(0.52) cm² (range 2.5 – 3.8 cm²). Doppler echocardiography showed excellent performance of the mitral valve components and valve competence could be achieved. During the in vitro studies no failure caused by tissue rupture was detected. The results of the in vitro studies revealed data for ΔP and effective orifice area superior to data obtained for standard 25 mm porcine bioprostheses.     

Introduction of a flexible polymeric heart valve prosthesis with special design for aortic position

Objective: Current prosthetic heart valves necessitate permanent anticoagulation or have limited durability and impaired hemodynamic performance compared to natural valves. Recently a polymeric valve prostheses with special design for mitral position demonstrated excellent in vitro and in vivo results with improved durability and no need for permanent anticoagulation. In this study, a respective flexible polymeric aortic valve is presented and in vitro and in vivo results are reported. Methods: The aortic prosthesis (ADIAM^® lifescience AG, Erkelenz, Germany) is entirely made of polycarbonaturethane. The tri-leaflet flexible prosthesis mimicks the natural aortic valve and has a diminished pressure loss and reduced stress and strain peaks at the commissures. The valve underwent long-term in vitro testing and in vivo-testing in a growing calve animal model (20 weeks, 7 aortic valves) and was compared to two different commercial bioprostheses. Results: The polymeric aortic heart valve substitute demonstrated excellent in vitro and in vivo hemodynamics. Five/seven animals with aortic PCU-prostheses had an excellent clinical long-term course. The explanted valves showed a variable degree of calcification. Two of the seven animals died at 27 and 77 days due to pannus overgrowth causing severe LVOTO without degeneration of the valve itself. Both animals with commercial bioprostheses had to be sacrificed because of congestive heart failure related to structural degeneration of the bioprosthesis after 10 and 30 days of implantation. There was no increased thrombogenity of the PCU valves compared to bioprostheses. Conclusion: The new flexible polymeric aortic valve prosthesis is superior to current bioprostheses in animal testing.     

Valve-related complications with the Hancock I porcine bioprosthesis. A twelve- to fourteen-year follow-up study

Valve-related morbidity and mortality after heart valve replacement with the Hancock I porcine bioprosthesis has been retrospectively analyzed. From June 1974 through December 1976, 253 Hancock I bioprostheses (150 mitral and 103 aortic) were inserted in 220 selected patients who survived the operation and had follow-up until June 1989 (mean follow-up 13.5 years, with an accumulative follow-up of 2956.4 patient-years). One hundred seventeen patients had mitral valve replacement, 70 had aortic valve replacement, and 33 had combined mitral and aortic valve replacement. There were 27 thromboembolic events. The probability of being free from thromboembolism at 14 years was 81.0% +/- 7.4% for the mitral valve replacement group, 85.4% +/- 6.7% for the aortic group, and 67.1% +/- 18.4% for the mitral-aortic group. Fifteen episodes of prosthetic valve endocarditis occurred. There were 10 instances of nonstructural dysfunction (paravalvular leaks) in seven mitral valves (4.6%) and in three aortic valves (2.9%). One hundred twenty-two bioprostheses in 106 patients resulted in structural deterioration. The probability of freedom from structural deterioration at 14 years was 37.2% +/- 3.9% for the mitral group, 43.9% +/- 7.1% for the aortic group, and 30.1% +/- 8.9% for the mitral-aortic group. The logistic regression analysis between age at the time of operation and bioprosthetic life (structural deterioration-free period) demonstrates a linear regression curve (r = 0.53). There were 56 late deaths (27 patients died at reoperation). The actuarial survival rate (including hospital mortality) at 14 years was 57.2% +/- 5.4% for the entire series, with no statistically significant difference between groups. The probability of remaining free from valve-related morbidity and mortality at 14 years was 16.7% +/- 4.8% for the mitral group, 20.8% +/- 6.2% for the aortic group, and 14.0% +/- 7.0% for the mitral-aortic group. The long-term results of this series show that the clinical performance of the Hancock I porcine valve appears satisfactory during the first 6 years. The behavior of this bioprosthesis at 14 years' follow-up changes drastically, because only a minor group of patients is free from valve-related complications, justifying the restriction of its use for selected patients.     

In vitro hemodynamic characteristics of prosthetic heart valves

The functional characteristics of the prosthetic heart valve are the hemodynamic characteristics when it has been ideally attached; in clinical practice, however, it is seldom that this artificial valve is ideally put in position because of the modality of changeable valve angle in deformed annulus and the narrow aortic root, orientation of the valve, anatomical factors, etc. Thus, we devised an attachment head for the prosthetic valve whose angle can freely be varied in order to evaluate the hemodynamic characteristics of five clinically-available mechanical prosthetic valves and two xenografts in the pulsatile circulation system in the mitral position by changing the angle and orientation of the valve attachment. The prosthetic valves used were St Jude Medical (SJM), Starr-Edwards ball (S-E), monostrut Bj?rk-Shiley (mB-S), Omniscience (OS), Omnicarbon (OC), Carpentier-Edwards Supra-annular (C-Es) and Carpentier Edwards Pericardial (C-Ep) whose tissue annulus diameter was 27 mm. The experimental instrument similar to that of Umezu et al. was prepared to determine the mean pressure gradient, output and calculated orifice area of each valve. At the same time, a recently-manufactured valve attachment head was employed to measure the output, pressure gradient and orifice area by altering the valve attachment angle and orientation and increasing the number of heart beats from 60 bpm to 160 bpm, and the following results were obtained: With the changeable angle valve, an angle was determined whose end was parallel to the flow path in association with changes in the attachment angle, and the orientation was such that the pressure gradient was reduced and the orifice area was increased.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hydrodynamic function of the second-generation mitroflow pericardial bioprosthesis

BACKGROUND: The hydrodynamic function of the smaller size Mitroflow Synergy stented pericardial bioprostheses has been studied in an in vitro fresh tissue aortic root model and compared with previous studies of free-sewn bioprostheses. METHODS: Three valves of each of the sizes 19, 21, and 23 mm were sutured into fresh tissue aortic roots and tested in a pulsatile flow simulator using two different ventricular input impedance conditions. A high-speed camera was used to study the leaflet opening and closing configurations. Mean pressure difference as a function of root mean square forward flow, effective orifice area, regurgitant volumes, and total energy loss across the valves was measured. RESULTS: Mean pressure difference with respect to root mean square forward flow decreased as the valve size increased. Thus effective orifice area increased as the valve size increased. The open leaflet configuration images showed that all three sizes of Mitroflow valves had a large circular orifice with minimal open leaflet deformation. All valves closed competently with no visible leakage and no closed regurgitant volume. The Mitroflow valves showed better effective orifice areas compared with previously tested frame-mounted porcine bioprostheses but lower effective orifice areas compared with porcine stentless bioprostheses; however, the open leaflet bending deformation was better than for any of the previously tested bioprosthetic valves. CONCLUSIONS: The hydrodynamic function of the Mitroflow Synergy stented pericardial bioprosthesis shows potential for good in vivo hemodynamic performance. The good hemodynamic performance combined with relative ease of implantation technique makes the pericardial valve a good valve in the aortic position, particularly in older patients with small annuli.     

More than ten years' follow-up of the Hancock porcine bioprosthesis in Japan.

From February 1975 through October 1981, 256 Hancock porcine bioprostheses (Johnson & Johnson Cardiovascular, King of Prussia, Pa.) (60 aortic, 169 mitral, and 27 pulmonary/tricuspid position) were implanted in 220 patients (104 male and 116 female, aged 9 to 67 years; mean 43.3) at Kyushu University Hospital in Japan. The procedures include 41 aortic valve replacements, 121 mitral valve replacements, 4 pulmonary valve replacements, 6 tricuspid valve replacements, and 48 combined valve replacements (31 aortic plus mitral, 13 mitral plus tricuspid, and 4 aortic plus mitral plus tricuspid). Hospital mortality was 6.4%. Follow-up was 98% during 8 to 14 (mean 10.5) years. Cumulative follow-up was 1836 patient-years and 2078 valve-years. At 10 years the overall actuarial survival rate, including hospital morality, was 70% +/- 3%, and freedom from valve-related mortality with sudden death was 87% +/- 3%. More than half of the current survivors required no anticoagulant therapy. Freedom from thromboembolism or anticoagulant-related hemorrhage (or both) and prosthetic valve endocarditis was common. Freedom from structural valve failure and reoperation declined more than 9 years after replacement of left-sided heart valves but not after replacement of right-sided heart valves. Sixty-seven patients underwent 68 repeat operations, and there were four deaths (5.9%). The rate of freedom from overall valve-related complications at 10 years was 62% +/- 8% for aortic valve replacement, 53% +/- 5% for mitral valve replacement, 80% +/- 13% for pulmonary/tricuspid valve replacement, and 42% +/- 9% for combined valve replacement. There was a significant difference between pulmonary/tricuspid valve replacement and combined valve replacement (p less than 0.05). The Hancock bioprosthesis is suitable for the replacement of valves in the right side of the heart but not for combined valve replacement.     

经主动脉路径同期手术修复主动脉根部或主动脉瓣病变合并的中度功能性二尖瓣关闭不全

目的探讨经主动脉路径同期手术修复主动脉根部或主动脉瓣病变合并的中度功能性二尖瓣关闭不全的手术技术,分析随访结果。方法回顾性分析2006年1月至2012年6月新华医院25例主动脉根部或主动脉瓣病变合并中度功能性二尖瓣关闭不全患者经手术治疗的临床资料,其中男18例,女7例;年龄42～75（57．9±9．6）岁。所有患者除主动脉根部或主动脉瓣病变均合并中度功能性二尖瓣关闭不全。Carpentier分型均为Ⅰ型。手术方法均在全身麻醉低温体外循环下行主动脉瓣置换或主动脉根部置换加二尖瓣成形术（均为经主动脉切口交界缝合成形）。通过门诊复查,电话等随访观察,评价二尖瓣及心脏结构和功能。结果术中食管超声心电图提示2例有残余微量反流,其余23例患者无反流,无瓣膜狭窄,成形效果满意。全组患者无死亡。术后复查超声心动图提示：左心房内径、左心室舒张期末内径与术前比较明显缩小（t=4．086,P=0．000;t=4．442,P=0．000）;左心室射血分数与术前比较有所降低（t=3．671,P=0．001）。术后二尖瓣瓣环直径与术前比较缩小[（32．4±3．6）mm vs．（35．6±6．4）mm]。术后二尖瓣瓣口压差[（1．4±0．7）mmHg vs．（1．5±0．7）mmHg],二尖瓣瓣口峰值压差[（3．7±2．2）mmHg vs．（3．3±1．5）mmHg]与术前比较差异无统计学意义（P〉0．05）。患者出院后随访23例,随访率92％,随访时间7～92（50．4±25.3）个月;2例失访。随访期间出现二尖瓣轻度反流3例。最后一次随访二尖瓣瓣环直径（33．9±4．6）mm,二尖瓣瓣口压差（1．3±0．6）mmHg,二尖瓣瓣口峰值压差（3．6±2．3）mmHg。结论主动脉瓣或主动脉根部手术时,经主动脉路径修复中度功能性二尖瓣关闭不全安全、方便、有效。     

Influence of bileaflet prosthetic mitral valve orientation on left ventricular flow--an experimental in vivo magnetic resonance imaging study.

OBJECTIVE: Orientation-related bileaflet mechanical valve flow and velocity studies in the downstream area are limited in mitral valve replacement studies. METHODS: In five sheep, ventricular blood flow was visualized prior to the implantation of a mitral Edwards Mira Bileaflet Mechanical Valve Model 9600. The implant orientation was either anatomic, with a 45 degrees rotation, or anti-anatomic, with a 90 degrees rotation. Sheep were positioned within an 1.5T field strength MR scanner (Magnetom Sonata; Siemens) to assess time-dependent three-dimensional blood flow velocities displayed as color-encoded vectors. RESULTS: The preoperative ventricular velocity profiles presented negligible individual variances. Streamlines passed homogeneously without any spatial differences into the left ventricle. Starting from the anatomical position, the areas with inhomogeneous and accelerated local blood velocities increased in comparison to the preoperative status. Rotating the prosthesis until it was in a 45 degrees position caused a significant increase in turbulence immediately downstream; fluids stagnated longer at the apex. In the anti-anatomic orientation, mean velocities decreased. In all three positions, but less so in the anatomical position, the flow pattern of the blood helix at the apex was disturbed. The intraventricular flow patterns between prostheses in the three orientations were, however, not significant when compared to the differences between physiologic intraventricular flow and any of the postoperative measurements. CONCLUSIONS: To achieve optimal hemodynamics, rotation of the mitral valve has to be considered carefully, as has long been known from aortic valve replacement studies. To this end, a method for qualitative assessment of left ventricular blood flow patterns was developed.     

Comparative Rest and Exercise Hemodynamics of Allograft and Prosthetic Valves in the Aortic Position

Background. Allograft aortic valve replacement has gained widespread acceptance. However, there is little information about in vivo allograft valve function at rest and during exercise.

Methods. Cardiac catheterization was performed to measure hemodynamic variables at rest and during supine bicycle exercise in 44 patients who had had aortic valve replacement using allograft valves or Bicer or St. Jude Medical prosthetic valves 19 to 27 mm in diameter. Sixteen patients received an allograft valve; 17, a Bicer valve; and 11, a St. Jude Medical valve. There were no significant differences between the three groups in age, body surface area, left ventricular end-systolic and end-diastolic volume indices, exercise cardiac index, exercise heart rate, or work load achieved. Left ventricular and ascending aortic pressures were measured simultaneously according to the transseptal method.

Results. The mean pressure gradient was generally higher for the Bicer and St. Jude Medical valves than for the allograft valves, both at rest and during exercise. Significant differences were obtained in patients with small-sized valves (21 and 23 mm); pressure gradients were higher in the prosthetic valve groups. In patients with large-sized prosthetic valves (25 mm), there were no significant differences between the three groups at rest and during exercise. However, there was no pressure gradient at all for allograft valves.

Conclusions. Exercise cardiac catheterization confirms that the allograft aortic valve is an ideal substitute from the hemodynamic aspect, particularly in patients with a small aortic root and in those who perform strenuous exercise.     

Borderline left ventricle.

The first problem to solve when dealing with the topic 'borderline left ventricle' is to find the appropriate definition. Several parameters have been taken into consideration, either morphometric (diameter of the mitral valve, indexed mitral valve area, left ventricular inflow dimension, left ventricular cross-sectional area, ratio between the apex-to-base left ventricular dimension and right ventricular dimension, left ventricular long axis to heart long axis ratio, left ventricular end diastolic volume, left ventricular mass index, ratio of the right/left ventricular wall thickness, presence of endocardial fibroelastosis, cardiac apex not formed by the left ventricle, diameter of the ventriculo-aortic junction, diameter of the aortic valve annulus and indexed aortic root diameter) as well as functional (left ventricular ejection fraction, left ventricular end diastolic pressure, mean pulmonary artery pressure, direction of the blood flow in the ascending aorta and at the level of the patent ductus arteriosus). Pre-operative determination whether the left ventricle is adequate to sustain the systemic circulation, or it may became adequate with the available surgical approaches, and therefore a bi-ventricular type of repair is feasible, can be extremely difficult, particularly in the presence of a 'borderline left ventricle'. In the clinical practice pediatric cardiologists and cardiac surgeons are faced with the problem of the 'borderline left ventricle' in four different groups of congenital heart defects: (a) aortic valve stenosis, (b) aortic coarctation, with or without hypoplastic aortic arch, (c) hypoplastic left heart complex, (d) right ventricular pressure and/or volume overload. In all the above situations in the presence of a left ventricle smaller than normal a very exhaustive approach has been reviewed in the decision making process, taking in account the literature reports as well as the personal experience. In each patient with 'borderline left ventricle' the elements to be considered for the decision making process between uni- and bi-ventricular type of repair, or for less ideal options of management, are the following: morphometric and functional parameters, hemodynamic data, available surgical options, results of the personal and institutional experience.     

In vitro analysis of performance of porcine xenografts with inward bending of stent posts: real-time measurement of valve orifice area using an area meter

The influence of inward bending of the stent posts on bioprosthetic valve function was assessed in a hydromechanical simulation of the left heart. A Carpentier-Edwards mitral xenograft (31 mm) and an aortic xenograft (27 mm) were used. Valve function was evaluated before and after the stent posts were bent inward 15 degrees by suture constriction of the tops of the three posts. To evaluate the effects of the stent-post deformity on valve performance, the mean transvalvular pressure drop during steady flow, the bioprosthetic valve orifice area, and the maximum valve opening and closing speeds during pulsatile flow were measured using an area meter. Steady-flow data showed identical transvalvular pressure drops, and no significant difference in valve performance was detected in the pulsatile-flow study under the two experimental conditions (i.e., normal valve and deformed valve). We conclude that a 15-degree inward bending of the stent posts does not appreciably affect valve function in vitro.     

Primary biventricular repair for interrupted aortic arch with left ventricular outflow tract obstruction and tricuspid valve regurgitation; report of a case

An interrupted aortic arch was diagnosed in a 10-day-old girl weighing 3.3 kg, as was perimembranous ventricular septal defect (VSD) and severe tricuspid valve regurgitation (TR). The subaortic diameter was 3.6 mm and the aortic valve (3.7 mm in diameter) was bicuspid. We chose definitive repair, modified Yasui procedure, because of severe TR and no straddling of mitral valve. In primary biventricular repair, we undertook extended aortic arch anastomosis. Left ventricular outflow tract reconstruction consisted of intracardiac rerouting from the VSD to the pulmonary artery by using expanded-polytetrafluoroethylene (ePTFE) and Damus-Kaye-Stansel (DKS) anastomosis. Right ventricular outflow tract reconstruction was performed by the Rastelli procedure with an ePTFE valved conduit. Moreover, we carried out semicircular annuloplasty for severe TR.     

Results of reoperation for primary tissue failure of porcine bioprostheses

Results of reoperation for primary tissue failure of porcine bioprostheses were evaluated in 574 patients discharged from the hospital from 1970 to 1981. A total of 413 had undergone isolated mitral valve replacement and 161 isolated aortic valve replacement. Through March, 1984, 88 patients (15%) had required reoperation: 59 had undergone mitral and 29, aortic valve replacement. Primary tissue failure was the main cause of bioprosthetic dysfunction; it occurred in 64 patients (46 mitral and 18 aortic) at a mean postoperative interval of 93 +/- 4 months (range 34 to 158). During the same period, 11 patients required reoperation for bioprosthetic endocarditis, 11 for paravalvular leak, and two for thrombosis. These patients are not included in this review. Reoperation for primary tissue failure was performed after a mean interval of 72 +/- 6 months (range 38 to 158) for patients with aortic bioprostheses and after 101 +/- 5 months (range 34 to 153) for those with mitral bioprostheses (p less than 0.05). Overall mortality at reoperation was 12.5%: 11% for the mitral group and 16% for the aortic group. In 62 patients (45 mitral and 17 aortic) primary tissue failure was caused by calcification of the cusps, associated with severe fibrous tissue overgrowth in seven. Bioprosthetic failure was caused by an intracuspal hematoma in one patient with mitral valve replacement and by lipid infiltration of the cusps in one patient with aortic valve replacement. Actuarial freedom from bioprosthetic primary tissue failure at 12 years is 61% +/- 5% for the mitral group and 69% +/- 7% for the aortic group. On the basis of our long-term follow-up of patients after mitral or aortic replacement with a porcine bioprosthesis, we conclude: primary tissue failure is the most frequent indication for reoperation in patients with a porcine bioprosthesis; calcification of the cusp tissue is the leading cause of primary tissue failure; reoperation for primary tissue failure may be a major concern, although mortality for elective cases is low; and the limited durability of porcine bioprostheses suggests their use be restricted to selected patients.     

Cardiac valve replacement in patients on dialysis: influence of prosthesis on survival

BACKGROUND: Mechanical valves have been recommended for patients on dialysis because of purported accelerated bioprosthesis degeneration. This study was undertaken to determine time-related outcomes in dialysis patients requiring cardiac valve replacement. METHODS: From 1986 to 1998, 42 patients on chronic preoperative dialysis underwent valve replacement; 17 received mechanical valves and 25 received bioprostheses. Age was similar in both groups: 54+/-18.5 years (mechanical) and 59+/-15.5 years (bioprosthetic, p = 0.4). Sites of valve replacement were aortic (27), mitral (11), and aortic and mitral (4). Follow-up was 100% complete. RESULTS: Survival at 3 and 5 years was 50% and 33% after mechanical valve replacement, and 36% and 27% after bioprosthetic valve replacement (p = 0.3). Four patients with bioprostheses required reoperation: 3 for allograft endocarditis and 1 at 10 months for mitral bioprosthesis degeneration. One patient who received a mechanical valve required reoperation. CONCLUSIONS: Prosthetic valve-related complications in patients on dialysis were similar for both mechanical and bioprosthetic valves. Because of the limited life expectancy of patients on dialysis, bioprosthesis degeneration will be uncommon. Therefore, surgeons should not hesitate to implant bioprosthetic valves in these patients.     

Selection criteria for aortic valve prostheses: mechanical, stented, or stentless valve or homograft?

A bioprosthesis is recommended for aortic valve replacement in patients 70 years (recently, 72 or 73 years) of age or older. The bovine pericardial valve is better suited in patients with a small aortic annulus less than 23 mm in diameter, and the porcine stented-bioprosthesis should be used in patients with an annulus larger than 25 mm. A mechanical valve is recommended in patients younger than 70 years of age with chronic atrial fibrillation or a history of thromboembolism. Moreover, a mechanical valve is selected in patients in whom it is necessary to enlarge the aortic root or annulus. When mitral valve replacement or coronary artery bypass grafting in performed concomitantly, the valve prosthesis is selected according to the age of the patient. A homograft is indicated in patients with active valve endocarditis having an abscess at the aortic annulus or root. When a patient with poor ventricular performance resulting from valvular disease is expected to undergo implantation of a ventricular assist device in the near future, a bioprosthesis is preferable.     

Evaluation of St. Jude Medical valve's long-term function by Doppler echocardiography.

In this study, the long-term function of St. Jude Medical valve (SJM valve) is evaluated by Doppler echocardiography. The subjects were 191 patients who underwent mitral or aortic valve replacement using SJM valve in our institute since July 1978 and had no clinical problem showing more than 50% of left ventricular ejection fraction. The patients were classified into 3 groups according to measurement period (within 5 years, 10 years and 15 years and more), and further classified by size and their results were compared. In every group by size, there was no significant difference among groups by measurement period. In the mitral valve position, peak pressure gradient and pressure half-time were not significantly different among groups by size. On the other hand, in the aortic valve position, pressure gradient in 21-mm group was significantly high among 21-mm, 25-mm, and 27-mm groups, showing a negative correlation with size. As the result, it was suggested that SJM valve kept a good function more than 15 years after operation. From these results, it was considered that the patients with small annlus of the aortic valve needed annulus-enlarging procedure or use of Hemodynamic Plus series valves to keep the size of more than 23 mm.     

A rapid structural degeneration of a porcine mitral valve

A 73-year-old woman underwent both mitral and aortic valve replacements with porcine heart valve prostheses because of severe mitral regurgitation and severe aortic regurgitation. Ten months after surgery, maximal flow velocity of the aortic valve reached 4.6 m/sec and moderate mitral regurgitation was detected. Repeated mitral and aortic valve replacements with mechanical heart valves were performed. The excised mitral valve showed thinning of the 3 cusps, and 2 of them were perforated. There was pannus overgrowth on the flow surface of the porcine aortic valve. Histologic examination of the excised mitral valve revealed marked inflammatory changes with macrophages.     

Use of the Alfieri edge-to-edge technique to eliminate left ventricular outflow tract obstruction caused by mitral systolic anterior motion

A 68-year-old woman with concentric left ventricular hypertrophy, prosthetic valve endocarditis with aortic root abscess, and sepsis had aortic root replacement with an aortic allograft. On weaning from cardiopulmonary bypass, she had hemodynamic instability caused by systolic anterior motion of the mitral valve, which resulted in a left ventricular outflow tract obstruction; the peak pressure gradient across the left ventricular outflow tract was 130 mm Hg, and there was moderately severe (3+) mitral regurgitation. After reinstitution of cardiopulmonary bypass, a central Alfieri edge-to-edge stitch was placed between the anterior and posterior leaflets of the mitral valve. This reduced the gradient across the left ventricular outflow tract to 10 mm Hg and eliminated the mitral regurgitation, which enabled successful separation from cardiopulmonary bypass.