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PubMed1991

[Ten years experience with the St. Jude Medical valve prosthesis for mitral valve replacement].

During the 10-year period between 1980 and December 1989, isolated mitral valve replacement (MVR) with the St. Jude Medical (SJM) valve prosthesis was performed on 404 patients at our hospital, and a long-term postoperative follow-up was conducted. There were 161 males and 243 females ranged in age from 1 year to 73 years. Early operative mortality was 5.2%. Follow-up period for 383 patients who discharged from the hospital was 1970.7 patient-years. Twenty of these patients died during the follow-up period, and a late mortality rate was 5.2%. During 10 years, thromboembolic event occurred in 8 patients. Four patients had anticoagulant-related bleeding, 4 had paravalvular leak, and 5 underwent re-operations. There was neither structural valve failure nor prosthetic valve endocarditis. Therefore, the actuarial survival rate and the valve-related death-free rate at 10 years were 83.2%, and 96.8%. Of the patients who survived, New York Heart Association class improved significantly (93% in classes II and III preoperatively and 71% in class I postoperatively). Linearized rates for thromboembolism, anticoagulant-related bleeding, and hemolysis were 0.41%, 0.20% and 0.36%/100 patient-years, respectively. The actuarial estimate of incidence free from all complications was 92.0% at 10 years. On the basis of this 10 years' experience, we believe that the SJM valve prosthesis is an excellent mechanical prosthesis for mitral valve replacement, in terms of hemodynamic performance and low thrombogenicity in patients receiving anticoagulants.

Adolescent↗
PubMed1986

[Tricuspid valve insufficiency in patients with rheumatic mitral valve disease: angiographic diameter of the tricuspid ring and function of the right ventricle].

Dilatation of the right ventricle and a consecutive enlargement of the tricuspid valve ring are thought to be the main causes of functional tricuspid regurgitation in patients with rheumatic mitral valve disease. To study the effect of right ventricular dilatation as well as the dimension of the tricuspid valve ring, right ventricular volume indices, ejection fraction, regional shortening, pulmonary artery pressure, and the diameter and systolic shortening of the tricuspid valve were determined in 67 patients with rheumatic mitral valve disease (NYHA class II and III) from biplane ventriculographies. Patients with right ventricular enlargement (greater than 90 ml/m2) were divided into groups with (group IIA) and without (group IIB) tricuspid regurgitation and compared with patients with normal right ventricular size and function without tricuspid regurgitation (group I). There was no difference in the end-diastolic volume index, in the afterload or in the diameter of the tricuspid ring. Right ventricular ejection fraction was decreased in group IIA (51 +/- 9% vs. 59 +/- 10% (IIB) and 61 +/- 6% (control); (p less than 0.05). Regional function was also decreased in group IIA. 73% of the patients with tricuspid regurgitation had right ventricular enlargement, but only 44% of the patients with right ventricular enlargement had tricuspid regurgitation. Thus right ventricular dilatation promotes the development of a tricuspid insufficiency, but is not the only cause. Additional factors like decreased local wall motion, alterations of the valve or the valve apparatus may also account for functional tricuspid regurgitation.

Angiography↗
PubMed1996

Ultrasonic decalcification of calcified valve and annulus during heart valve replacement.

A heavily calcified heart valve annulus increases the likelihood of sequelae after prosthetic valve replacement. Such sequelae include cerebral embolism, paravalvular leakage, valvular dysfunction, rhythm disturbance, hemolysis, communication of the heart chambers, and rupture of the posterior wall of the left ventricle. From January 1991 through June 1994, we performed heart valve replacement on 30 patients, using an ultrasonic surgical aspirator to remove calcific deposits. We placed aortic valve prostheses in 12 patients, mitral valve prostheses in 13 patients, and both aortic and mitral prostheses in 5 patients, after ultrasonic débridement of calcified annuli. All patients were re-examined 6 months after surgery: echocardiographic study showed no paravalvular leakage or valve-related complications. In our experience, ultrasonic decalcification of the annulus is superior to traditional methods. We advocate the use of ultrasonic débridement as an adjunctive tool in calcified heart valve replacement.

Adult↗
PubMed1985

Actuarial analysis of the risk of prosthetic valve endocarditis in 1,598 patients with mechanical and bioprosthetic valves.

We reviewed the charts of 1,598 patients undergoing valve replacement at the National Institutes of Health, Bethesda, Md, from 1956 through 1981. Retrospective analysis disclosed that 43 patients had prosthetic valve endocarditis (PVE). Twelve patients had early (less than 60 days after operation) and 31 patients had late (greater than 60 days after operation) endocarditis. The cumulative risk was 3% at five years and 5% at ten years. We also calculated the interval risk of PVE. The high risk of early PVE development peaked 15 days after operation. The peak risk was 45 episodes per 100,000 patient days. The risk then declined rapidly and from 150 days to 20 years remained stable at approximately one episode per 100,000 patient days. Nine hundred fifty-two patients had valve replacement with a Starr-Edwards prosthesis and 363 patients had valve replacement with a bioprosthetic valve; there was no significant difference in the risk of PVE in either group. Neither the valve make, position, model, nor the number of valves implanted affected the frequency of PVE or the mortality. Actuarial techniques disclosed the high early risk of PVE, the prolonged risk of PVE up to 150 days after operation, and the low but persistent risk late after operation. There was no significant difference in the risk of PVE in patients with bioprosthetic v mechanical valves.

Actuarial Analysis↗
PubMed1986

Left atrioventricular valve after surgical repair in atrioventricular septal defect with separate valve orifices ("ostium primum atrial septal defect"): an echo-Doppler study.

Left atrioventricular (AV) valve dysfunction is the most frequent major postoperative hemodynamic complication in patients with AV septal defect. The anatomy and function of the left AV valve were investigated in 64 patients with separate valve orifices (ostium primum atrial septal defect) who had survived corrective surgery. M-mode and cross-sectional echocardiograms of the left AV valve were obtained. Doppler flow tracings were obtained at the left AV valve orifice to determine if regurgitation was present. The findings were related to the position of the commissures between the leaflets, the size of the 3 leaflets and the position of the papillary muscles. Left AV valve regurgitation was present in 29 of 51 patients (57%). These patients had a significantly different left AV valve leaflet configuration, characterized by a large mural leaflet and a small inferior bridging leaflet. The size of the superior bridging leaflet is not a determinant factor. Thus, the configuration of the left AV valve in AV septal defect is related to the postoperative functional result. Awareness of the echocardiographic anatomy may influence the surgical approach to this defect.

Echocardiography↗
PubMed2006

Type I and type III collagen synthesis and composition in the valve matrix in aortic valve stenosis.

Changes in the collagenous matrix may contribute to the pathogenesis and progression of human aortic valve stenosis (AS). To evaluate the significance of collagen I and III in the pathogenesis of AS, we studied their synthesis in diseased valves. Type I and type III collagen mRNA expression and the immunohistochemical localization of the collagen antigens were studied from 36 AS and 2 normal aortic valves. The concentrations of propeptides and telopeptide structure of type I (PINP, PICP, and ICTP) and those of III collagens (PIIINP and IIINTP) were measured by radioimmunoassays in soluble tissue extracts and trypsin-solubilized calcified and non-calcified matrices of 11 AS and 24 healthy aortic valves of different ages. The synthesis of type I collagen, localized in the myofibroblasts adjacent to calcified nodules, was two- to three-fold in the AS samples compared to the controls. The proportion of collagen in the total protein fraction was 90% in the healthy valves, 50% in the non-calcified matrix, and 10% in the calcified matrix of AS valves. In the calcified valves, the ICTP content was six-fold compared to the age-matched controls and two-fold compared to the young control group. In the controls, the amount of ICTP in type I collagen decreased with age (r=-0.908, p<0.001) and was replaced by other cross-linked C-telopeptide structure. The concentration of type III collagen decreased during aging (r=-0.753, p<0.001). The decrease in total collagen content, despite the increase in type I collagen synthesis indicates an increase in collagen turnover in AS. The calcification of the aortic valves is accompanied by increased amount of ICTP in type I collagen.

Adolescent↗
PubMed2006

Short and midterm results of aortic valve cusp extension in the treatment of children with congenital aortic valve disease.

BACKGROUND: We evaluated our experience with aortic valve cusp extension techniques to identify predictors of successful intraoperative repair and subsequent durability. METHODS: Twenty-two children (ages 5-18 years) underwent aortic cusp extension with autologous pericardium between 1999 and 2005. Sixteen children had previous surgical or percutaneous intervention. Ten children had bicuspid aortic valves. Cusp extensions were performed on 1 cusp in 3 patients, 2 cusps in 3, and 3 cusps in 16. Serial echocardiographic measures (n = 81) were obtained during a 5-year period and underwent blinded review. Longitudinal trajectories of ventricular and aortic valve function were modeled using mixed linear regression analysis. RESULTS: There was no hospital or late mortality. Five-year freedom from valve replacement was 75%. Comparison of preoperative and post-repair echocardiograms demonstrated reductions in aortic insufficiency (decreased in jet-width/aortic valve diameter ratio from 0.39 +/- 0.12 to 0.22 +/- 0.11; p < 0.0001), aortic stenosis (decreased in peak aortic valve gradient from 41 +/- 25 mm Hg to 29 +/- 15 mm Hg; p = 0.04), and left ventricular end-diastolic dimensions Z-score (decreased from 1.39 +/- 0.38 to 1.16 +/- 0.34; p < 0.001). During the follow-up period, post-repair jet-width and aortic valve diameter increased nonlinearly (p < 0.001). Patients with postoperative peak aortic gradients greater than 30 mm Hg had progression of aortic stenosis, whereas those with lesser postoperative peak gradients tended to regress during follow-up (p < 0.001). The decrement in Z-score of the left ventricular end-diastolic dimensions remained stable during the follow-up period. CONCLUSIONS: Aortic valve cusp extension can result in acceptable hemodynamic results with stabilization of left ventricular geometry. However, residual lesions are common and progression and regression of these lesions can be predicted based on echocardiographic data.

Adolescent↗
PubMed1987

The equilibrium position of the mitral valve: an accurate model of mitral valve motion in humans.

A "semiopen" diastolic equilibrium position of the mitral valve that is assumed in the absence of transmitral flow has been demonstrated in instrumented dogs. It has been suggested that the papillary muscles and chordae tendineae play an integral role in returning the valve to this position after initial diastolic opening. To determine whether such a model of mitral valve motion is valid in noninstrumented humans without underlying valvular disease, M-mode and Doppler ultrasound studies were performed in 6 subjects who underwent prolonged periods of ventricular diastole and atrial inactivity. After maximal opening, the mitral valve assumed a stable open position in which mean separation of the anterior and posterior mitral leaflets was 52% of maximal separation. This position was maintained for a mean duration of 585 ms, during which time transmitral flow fell to 0 m/s. Peak mitral valve opening preceded the early transmitral flow peak by an average of 42 ms, suggesting an active closure of the mitral valve as flow continued to accelerate. It is concluded that a semiopen equilibrium position of the mitral valve is assumed during prolonged diastolic periods in the absence of transmitral flow and is an accurate model describing diastolic mitral valve motion in noninstrumented humans. The chordae tendineae and papillary muscles may actively participate in the genesis and maintenance of the equilibrium position.

Adult↗
PubMed2003

Cell characterization of porcine aortic valve and decellularized leaflets repopulated with aortic valve interstitial cells: the VESALIO Project (Vitalitate Exornatum Succedaneum Aorticum Labore Ingenioso Obtenibitur).

BACKGROUND: Heart valve bioprostheses for cardiac valve replacement are fabricated by xeno- or allograft tissues. Decellularization techniques and tissue engineering technologies applied to these tissues might contribute to the reduction in risk of calcification and immune response. Surprisingly, there are few data on the cell phenotypes obtained after cellularizing these naturally-derived biomaterials in comparison to those expressed in the intact valve. METHODS: Aortic valve interstitial cells (VIC) were used to repopulate the corresponding valve leaflets after a novel decellularization procedure based on the use of ionic and nonionic detergents. VIC from leaflet microexplants at the third passage were utilized to repopulate the decellularized leaflets. Intact, decellularized and repopulated valve leaflets and cultured VIC were examined by immunocytochemical procedures with a panel of antibodies to smooth muscle and nonmuscle differentiation antigens. Intact and cellularized leaflets were also investigated with Western blotting and transmission electron microscopy, respectively. RESULTS: Myofibroblasts and smooth muscle cells (SMC) were mostly localized to the ventricularis of the leaflet whereas fibroblasts were dispersed unevenly. Cultured VIC were comprised of myofibroblasts and fibroblasts with no evidence of endothelial cells and SMC. Two weeks after VIC seeding into decellularized leaflets, grafted cells were found penetrating the bioscaffold. The immunophenotypic and ultrastructural properties of the grafted cells indicated that a VIC heterogeneous mesenchymal cell population was present: fibroblasts, myofibroblasts, SMC, and endothelial cells. CONCLUSIONS: VIC seeding on detergent-treated valve bioscaffolds has the cellular potential to reconstruct a viable aortic valve.

Animals↗
PubMed1995

A working cardiac valve phantom for radiographic assessment of prosthetic heart valves.

RATIONALE AND OBJECTIVES: A working valve phantom (WVP) that both exercises the valve occluder and simulates movements of the mitral annulus is described. It was designed to develop a method for radiographic detection of a single broken leg of the two-legged Björk-Shiley convexo-concave (C/C) heart valve outlet strut. METHODS: The WVP consists of a pneumatically driven left ventricular assist device immersed in 22 cm of water. Left ventricular assist device annulus movements are generated by systolic turgor and diastolic relaxation of the aortic outflow graft within limits set by the holding fixture design. RESULTS: WVP images were comparable in attenuation, valve motion, and diagnostic sensitivity to clinical C/C valve images and were effective in assessing leaflet excursions in another valve model. Techniques developed in the WVP have proved successful in the clinical detection of C/C valves that have a single broken leg but that show normal function in all other tests. CONCLUSION: The WVP can be a useful tool for developing refined radiographic assessments of prosthetic heart valves.

Heart Valve Prosthesis↗
PubMed1997

Effects of tilting disk heart valve gap width on regurgitant flow through an artificial heart mitral valve.

While many investigators have measured the turbulent stresses associated with forward flow through tilting disk heart valves, only recently has attention been given to the regurgitant jets formed as fluid is squeezed through the gap between the occluder and housing of a closed valve. The objective of this investigation was to determine the effect of gap width on the turbulent stresses of the regurgitant jets through a Björk-Shiley monostrut tilting disk heart valve seated in the mitral position of a Penn State artificial heart. A 2 component laser-Doppler velocimetry system with a temporal resolution of 1 ms was used to measure the instantaneous velocities in the regurgitant jets in the major and minor orifices around the mitral valve. The gap width was controlled through temperature variation by taking advantage of the large difference between the thermal expansion coefficients of the Delrin occluder and the Stellite housing of Björk-Shiley monostrut valves. The turbulent shear stress and mean (ensemble averaged) velocity were incorporated into a model of red blood cell damage to assess the potential for hemolytic damage at each gap width investigated. The results revealed that the minor orifice tends to form stronger jets during regurgitant flow than the major orifice, indicating that the gap width is not uniform around the circumference of the valve. Based on the results of a red blood cell damage model, the hemolytic potential of the mitral valve decreases as the gap width increases. This investigation also established that the hemolytic potential of the regurgitant phase of valve operation is comparable to, if not greater than, the hemolytic potential of forward flow, consistent with experimental data on hemolysis.

Blood Flow Velocity↗
PubMed1994

Cartilage in the aortic valve and its relationship with the aortic valve morphology in Syrian hamsters.

We conducted a light-microscopic histologic study of the aortic valves of 224 Syrian hamsters aged between 1 and 771 days. Most of the hamsters examined belonged to a single laboratory-inbred family with a high incidence of bicuspid aortic valves (BAVs). In 146 specimens the aortic valve was tricuspid, and in 107 of them the ventral commissure was more or less fused. The remaining 78 specimens showed a BAV with the aortic sinuses oriented ventrodorsally. In 33 BAVs a raphe was located in the ventral aortic sinus. Cartilaginous foci were present in the aortic valves of 86 specimens, 40-771 days old. The foci were located at two different sites, namely in the ventral wall of the valve and/or in the dorsal aortic sinus. Statistical analyses substantiate that (1) chondrogenesis begins earlier in BAVs, and especially in those having a raphe, than in tricuspid aortic valves and (2) the location of the cartilaginous foci is significantly associated with the morphology of the aortic valve. The present findings support the hypothesis that, in the Syrian hamster, cartilage forms in the aortic valve as a response to locally intense mechanical stimulation.

Animals↗
PubMed1996

Valve detachment after aortic valve replacement--a successfully reoperated case with the Cabrol technique.

A 50-year-old Japanese male was admitted with a 1 month history of progressive shortness of breath, palpitations, and intermittent low-grade fever. On admission, a musical diastolic murmur (sea-gull murmur) was heard on the 3rd left sternal border. Blood studies showed an accelerated erythrocyte sedimentation rate, and positive C-reactive protein. Retrograde aortography revealed severe aortic regurgitation. At the operation, the aortic wall was remarkably thickened, and the aortic valve commissures between the right and left coronary cusps and between the left and non-coronary cusps had completely detached from the aortic wall. The aortic valve was replaced with a St Jude Medical valve using pledgeted sutures. Histologic studies of the aorta and aortic valve revealed no evidence of any pathologic changes. Echocardiography performed 82 days after aortic valve replacement showed severe paravalvular leakage and valve detachment. At the reoperation, the prosthetic valve was detached from the extremely edematous and fragile native aortic annulus. There was no vegetation or abscess formation. Aortic root replacement with the Cabrol technique was performed using a composite graft in which the prosthetic valve was placed 1 cm above the proximal extremity to reduce the tension on the suture line and the aortic annulus. Histologic study of the aorta after the reoperation showed non-specific inflammatory disease. The patient, who received steroid therapy, has recovered without any signs of graft detachment or pseudoaneurysm formation.

Aortic Valve↗
PubMed1999

Identification and characterization of calcifying valve cells from human and canine aortic valves.

BACKGROUND AND AIM OF THE STUDY: Cardiac valve calcification is the predominant pathology in patients needing valve replacement. The aim of this study was to determine if aortic valve cells calcify spontaneously and, if so, to characterize the nodular complex and response to growth factors. METHODS: Aortic valves were obtained from humans undergoing surgical valve replacement, and from female dogs. The valvular endothelium was removed and explants cultured in medium. RESULTS: A population of valvular interstitial cells spontaneously formed distinct calcified nodules containing hydroxyapatite within two to three weeks in canine and within six weeks in human aortic valves. The nodules contained an inner ring of dead cells surrounded by an outer ring of living cells. Cells associated with nodules had osteoblast-like characteristics and stained positively for extracellular bone matrix proteins. Incubating canine cells with potential calcifying stimuli tested the stimulus for calcification. The rate of nodule formation was increased with transforming growth factor beta-1 (+25 nodules), 25-hydroxycholesterol (+9 nodules) and bone morphogenetic protein 2 (+4 nodules) as compared with vehicle control (+3 nodules) over 25 days. CONCLUSIONS: We identified a population of valvular interstitial cells with osteoblast-like characteristics that spontaneously form calcific nodules in cell culture. In addition, the rate of calcific nodule formation was increased with transforming growth factor beta-1 and 25-hydroxycholesterol. Further study of these 'calcifying valve cells' may yield a new in vitro model for testing therapy aimed at preventing calcific valve stenosis.

Animals↗
PubMed1989

The morphology of the normal aortic valve as compared with the aortic valve having two leaflets.

We studied 30 normal aortic valves and 64 aortic valves with only two leaflets to examine their morphologic components. The components of the aortic valve are the leaflets, the sinuses, and the interleaflet triangles. The first part of our study shows the relationship of these component parts of the normal aortic valve to the other cardiac structures. The second part shows a wide variation in the architecture of valves having two leaflets. Having produced criteria for the number of sinuses and the number of leaflets, we discovered that previous criteria used in the definition of valves with two leaflets are inadequate when the whole valvular complex is considered. Only seven valves in the study have two leaflets supported by two sinuses. The evidence points to the other valves having started with three leaflets but becoming bicuspid during either intrauterine or postnatal life.

Adult↗
PubMed1985

Externally stented polytetrafluoroethylene valved conduits for right heart reconstruction. An experimental comparison with Dacron valved conduits.

Valve-containing conduits have made possible the repair of many congenital anomalies that involve right ventricular-pulmonary arterial discontinuity. The distressing problem of neointimal peel formation with eventual conduit obstruction in patients with Dacron valved conduits has led to the need for premature replacement in many patients. Externally stented polytetrafluorethylene has demonstrated superior patency in the venous system experimentally and clinically and was believed to have potential advantages over Dacron for conduit construction. This study compares the transconduit resistance and the thickness of the neointimal peel in right ventricular-pulmonary arterial conduits constructed of externally stented polytetrafluoroethylene with those of woven Dacron. The 19 mm externally stented polytetrafluoroethylene conduits (Impra, Inc.) containing a Hancock porcine valve (Extracorporeal Inc.) were implanted in six adult mongrel dogs followed by proximal occlusion of the pulmonary artery. In six additional animals, a Dacron valved conduit of similar size and length was inserted. Cardiac output, transconduit gradient, and resistance were measured at operation and at 3 months. All conduits were subsequently explanted, opened longitudinally, and the thickness of the neointimal peel (excluding suture lines) measured. No hemodynamic differences were noted during the 3 month follow-up. However, the thickness of the neointimal peel was fourfold greater in Dacron conduits (609 +/- 144 mu) than in the conduits constructed of externally stented polytetrafluoroethylene (156 +/- 50 mu) (p less than 0.01). The thick peel in Dacron conduits extended into the outflow portion of the porcine valve cusps and prevented their full excision. The neointima in externally stented polytetrafluoroethylene conduits was thin and uniform and did not extend onto the leaflets or limit their mobility. This study demonstrated that the early hemodynamic performance of externally stented polytetrafluoroethylene conduits was comparable to that of Dacron conduits; Dacron conduits were subject to an accelerated rate of peel formation that affected leaflet mobility and may be a factor in early valve degeneration; a thin neointima formed in externally stented polytetrafluoroethylene conduits and valve leaflet motion was preserved. This study showed that externally stented polytetrafluoroethylene conduits offer advantages over Dacron valved conduits and warrant clinical application.

Animals↗
PubMed1979

[The meaning of the systolic progression of the mitral valve for the outflow tract obstruction in hypertrophic obstructive cardiomyopathy (HOCM). Studies by means of a valve model].

We constructed two valve models in order to investigate the cause of SAM of the mitral valve and the cause of the outflow tract obstruction in HOCM. With model 1 we were able to demonstrate that a subvalvular obstruction created a SAM of the mitral valve, there was also a pressure gradient distal to the obstruction, the valve itself did not create any obstruction. With model 2 we demonstrated that three causes were responsible for an outflow tract obstruction: 1. A narrow outflow tract even after removal of the mitral valve. 2. A position of the mitral valve close to a protruding septum and relatively short chordae tendineae. 3. A SAM of the mitral valve with apposition to the septum due to a Venturi effect. We were able to create a typical bisferiens poststenotic pressure curve in presence of a monophasic prestenotic curve. We conclude from our investigation that for the SAM of the mitral valve as well as for the outflow tract obstruction different anatomic structures may be responsible, which cause simular hemodynamic abnormalities. These abnormalities are most prominent in HOCM but not necessarily linked with this disease.

Cardiomyopathy, Hypertrophic↗
PubMed1997

[Aortic valve replacement with the Toronto stentless porcine valve in a patient with clipping for cerebral arterial aneurysm].

A 48-year-old man, who had a cerebral arterial aneurysm, was admitted in our institution for operation of aortic valve stenosis. At first, he underwent clipping for cerebral arterial aneurysm under precise management of his hemodynamic condition. After the clipping operation, we performed aortic valve replacement with the Toronto stentless porcine valve because no anticoagulant therapy was ideal for patient with cerebrovascular disease and larger effective orifice area was preferable for stenotic aortic annulus. By means of echocardiography, mean pressure gradient of the aoric valve decreased from 42 mmHg to 22 mmHg after the valve operation. He was discharged from the hospital on the 23rd postoperative day, and he has been doing well without thromboembolic events and bleeding complications for five postoperative months. This experience suggest that the Toronto stentless porcine valve might be one of the valve of choice for patients with aortic valve disease and cerebrovascular disease.

Aortic Valve Stenosis↗