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At least 343 records · Page 19Linked to original sources
PubMed1992

Aortic valve infection. Risk factors for death and recurrent endocarditis after aortic valve replacement.

Patients (n = 195) undergoing aortic valve replacement (n = 209) for native or prosthetic valve endocarditis were studied to determine risk factors for death and recurrent endocarditis and also to determine the valve type least likely to be associated with recurrent endocarditis. Ten-year survival was 60%, the highest risk of dying occurring within the first 3 postoperative months. Risk factors for death in this early phase included increased urea concentration, higher New York Heart Association functional class, prosthetic valve endocarditis, infection status (lower in patients with healed endocarditis), longer duration of cardiopulmonary bypass, and nonuse of an allograft valve. In the late phase (beyond 3 months), risk factors included age at operation and Staphylococcus aureus infection (only in New York Heart Association functional class V). Ten years after aortic valve replacement, 79% of valves were free of recurrent endocarditis. The highest risk of recurrence was in the first 4 months. Longer duration of cardiopulmonary bypass was a weak risk factor for recurrent endocarditis in the early phase, and in the late phase risk factors were S. aureus infection (only in New York Heart Association functional classes III, IV, and V) and the use of now discontinued biologic valves. Allograft aortic valve replacement was shown to be associated with a low and constant risk of recurrent endocarditis, whereas other valve types were associated with a high early risk. The allograft valve should be the preferred replacement device for aortic root infection.

Adult↗
PubMed1992

Aortic valve replacement for active infectious endocarditis in 108 patients. A comparison of freehand allograft valves with mechanical prostheses and bioprostheses.

A total of 108 patients hospitalized with active (acute) endocarditis on either a native aortic valve (n = 66) or a previously inserted replacement device (n = 42) underwent aortic valve replacement because they were too ill for hospital discharge. A nonstented aortic allograft valve was used in 78 patients and prosthetic (mechanical or bioprosthetic) valves in 30 patients. The survival rate was 82% at 1 months, 73% at 1 year, 64% at 5 years, and 36% at 15 years. It was better in patients with native valve endocarditis than prosthetic valve endocarditis. The incremental risk factors for death in the early phase postoperatively were older age at operation, higher New York Heart Association functional class, and a larger number of previous aortic valve procedures. There were 13 episodes of recurrent endocarditis, giving an actuarial freedom of 80% at 10 years. The hazard function for recurrent endocarditis had only a low constant phase when allograft valves were used, which contrasted with the existence of a high peaking early phase (in addition to the constant phase) when prosthetic devices were used. No risk factors for recurrent endocarditis were found in patients receiving a prosthesis, and "localized" versus "extensive" endocarditis was the only risk factor when an allograft was used. Reoperation was performed in 24 patients for a variety of reasons, and freedom from reoperation was 61% at 10 years. It is concluded that the allograft valve is the valve of choice when aortic valve replacement is required for active endocarditis.

Adult↗
PubMed1994

Aortic valve replacement with a stentless porcine aortic valve. A six-year experience.

A stentless porcine aortic valve was used for aortic valve replacement in 123 patients from 1987 to 1993. The mean age of 86 men and 37 women was 61 +/- 12 years. Most patients had aortic stenosis; one-third had coronary artery disease and six had mitral valve disease. The stentless valve was secured in the subcoronary position by the same technique used for a freehand aortic valve homograft. The size of valve was based largely on the diameter of the sinotubular junction of the aortic root. The mean valve size was 26.5 mm (range 19 to 29 mm) and 87% were 25 mm or larger. Two operative deaths occurred, one the result of myocardial infarction and the other the result of infective endocarditis. Patients have been followed up from 3 to 77 months, mean 22 months. Three late deaths, none related to the valve, have occurred. The actuarial survival at 6 years was 91% +/- 4%. Four transient cerebral ischemic events have occurred, but two patients had extracranial cerebrovascular disease. One patient had endocarditis late in the postoperative period and required reoperation. All patients had Doppler echocardiographic studies before discharge from the hospital, 3 to 6 months later and annually. Only 15 patients have aortic insufficiency, trivial in 6 and mild in 9. The peak and mean systolic gradients decreased significantly during the first 3 to 6 months after implantation (p < 0.001), and the effective valve areas increased significantly during this time interval (p < 0.001). This improvement in valve hemodynamics is believed to be due to remodeling of the aortic root and regression of left ventricular hypertrophy. The results of aortic valve replacement with this stentless bioprosthesis have been excellent and justify its continued use in older patients.

Adult↗
PubMed1995

[Mitral valve replacement with homemade heterologous pericardial roll valve for mitral regurgitation after repair of complete atrioventricular septal defect].

Repair of using the double patch method was performed on a 6-month old child with Down's syndrome. However, at 1 year and 4 months (BW: 3.6 kg), the patient's resulting mitral regurgitation became severe and clinically unmanageable, necessitating further operation. At operation the anterior leaflet of the mitral valve was lifted up at the anterolateral side due to the patch attached to the interventricular septum, which restricted the valve from closing completely. Moreover, secondary severe hardening of the valve tissue made it difficult to reconstruct the valve. Since the diameter of the valve was only 13 mm after resection, making the impossible use of a standard prosthetic valve, we constructed a new roll valve out of a heterologous pericardium. Almost no regurgitation was observed and prognosis was favorable although a pattern of mitral stenosis was observed. The patient died 6 months later due to the worsening of respiratory infection before a reoperation could be performed. Post mortem examination revealed comparatively good valve function except mitral stenosis due to inadequate valve size. This technique has practical application for mitral valve replacement of small valve annuli of infants when other methods are not feasible.

Bioprosthesis↗
PubMed2000

Long-term survival after valve replacement with Björk-Shiley CC valves. Björk-Shiley Study Group.

Information on the life expectancy of Bjork-Shiley convexo-concave (BScc) valve recipients is necessary when considering prophylactic replacement. However, little is known about the late results after valve replacement with BScc valves. We describe long-term survival and its determinants of the Dutch BScc cohort and compare mortality figures with those of the general population and those used in guidelines for prophylactic replacement. Follow-up was obtained on all Dutch BScc valve recipients (n = 2,264) (end of study 1996). Survival over a 15-year period and its determinants were described using the Kaplan-Meier product-limit method and Cox regression, respectively. Standardized mortality ratios (SMRs) were used to compare mortality rates of BScc valve recipients who survived at least 30 days after surgery with the Dutch population rates. Survival at 15 years for aortic, mitral, and double valve recipients was 55.0% (95% confidence interval [CI] 51.9 to 58.1), 40.8% (95% CI 37.1 to 44.4), and 38.6% (95% CI 33.2 to 43.9), respectively. The determinants of survival were patient, history, and procedure related. The SMR for all BScc valve recipients was 4.2 (95% CI 3.4 to 5.2) in the first year of follow-up, after which it decreased to 2.0 (95% CI 1.8 to 2.3) and remained constant until the 14th year. SMRs depended on time since implantation, age at the time of implantation, and position of the valve replaced. Most of life expectancy estimates in prophylactic replacement guidelines of BScc valves underrate the true survival estimates. Age, valve position, and time- specific risks of death after valvular surgery should be accounted for. Different excess mortality rates should be applied for patients from different age groups: the older the patient the lower the excess.

Aortic Valve↗
PubMed1998

Aortic valve replacement with stentless and stented porcine valves: a case-match study.

OBJECTIVES: To assess the potential benefits of the hemodynamic superiority of stentless valves, we conducted a case-match study among patients who underwent aortic valve replacement with two types of porcine bioprostheses: the Toronto SPV and the stented Hancock II bioprosthesis. METHODS: Preoperative clinical variables predictive of death after aortic valve replacement were determined by a stepwise logistic regression analysis in a series of 908 consecutive patients who received porcine aortic bioprostheses during a 14-year interval. Advanced age, New York Heart Association functional class IV, left ventricular ejection fraction of less than 30%, and coronary artery disease were independent predictors of death. On the basis of these four variables, 198 pairs of patients who survived aortic valve replacement with stentless and stented porcine valves were matched. The follow-up, truncated to the shortest interval for each matched pair, was 43 +/- 24 months for both groups. RESULTS: At 8 years the actuarial survival was 91% +/- 4% for the Toronto SPV group and 69% +/- 8% for the Hancock II group (p = 0.006); the freedom from cardiac-related death was 95% +/- 4% for the Toronto SPV and 81% +/- 8% for the Hancock II (p = 0.01); the freedom from any valve-related complication was 81% +/- 5% for the Toronto SPV and 50% +/- 10% for the Hancock II (p = 0.008). A Cox proportional hazard model demonstrated a significant reduction in cardiac mortality rates and valve-related morbidity in patients who received the Toronto SPV bioprosthesis. CONCLUSIONS: Although it is possible that confounding factors may have played a role in the clinical outcomes of this case-control study, the study suggests that aortic valve replacement with a stentless porcine valve enhances survival. This is believed to be due to the hemodynamic superiority of these valves.

Adult↗
PubMed2001

Outlet strut fracture of Björk-Shiley convexo-concave valves: can valve-manufacturing characteristics explain the risk?

BACKGROUND: Björk-Shiley 60 degrees convexo-concave prosthetic heart valves (Shiley, Inc, Irvine, Calif, a subsidiary of Pfizer, Inc) continue to be a concern for approximately 35,000 nonexplanted patients worldwide, with approximately 600 events reported to the manufacturer to date. Fractures of the outlet struts of the valves began to appear in the early 1980s and have continued to the present, but their causes are only partially understood. METHODS: A matched case-control study was conducted evaluating manufacturing records for 52 valves with outlet strut fractures and 248 control subjects matched for age at implantation, valve size, and valve position. RESULTS: In addition to the risk factors recognized as determinants of outlet strut fracture, the United Kingdom case-control study has observed 7- to 9-fold increased risk with performance of multiple hook deflection tests. This test was performed more than once, usually after rework on the valve. Six valves in this study underwent multiple hook deflection tests, of which 4 experienced an outlet strut fracture. Cracks and further rework were noted for these valves. Significant associations were also observed between outlet strut fracture and disc-to-strut gap measurements taken before the attachment of the sewing ring. CONCLUSIONS: It is our view that a combination of factors related to valve design, manufacturing process, and patient characteristics are responsible for outlet strut fractures of Björk-Shiley convexo-concave valves. Multiple hook deflection tests have emerged as a potential new risk factor for outlet strut fracture in both The Netherlands and the United Kingdom. This factor appears to be correlated with the presence of other abnormalities. A further study is needed to investigate the factors correlated with multiple hook deflection tests. On confirmation of risk, the presence of multiple hook deflection tests may be added to equations, quantifying the risk of outlet strut fracture for comparison against risk of mortality and serious morbidity from explant operations.

Analysis of Variance↗
PubMed2001

Tricuspid valve involvement in combined mitral and aortic valve surgery.

BACKGROUND: Combined mitral and aortic valve disease requiring surgery may involve the tricuspid valve as well. Our treatment policy is conservative especially for tricuspid regurgitation which is operated on when severe only. METHODS: A retrospective study was performed at a tertiary and secondary referral center for cardiovascular disease. Over a 15-year period, 65 consecutive patients underwent aortic and mitral surgery with concomitant tricuspid regurgitation and/or stenosis. Fifty-five/65 (85%) patients were in NYHA class III-IV. Fifty-eight/65 (89%) patients had tricuspid regurgitation secondary to right chamber dilatation and 7/65 (11%) had tricuspid stenosis and/or regurgitation because of previous endocarditis. Twenty-two/65 (34%) tricuspid valves were operated on: 18/22 (82%) de Vega annuloplasty, 2/22 (9%) commissurotomies and 2/22 (9%) prosthetic valves. Mortality and complications were recorded during a mean follow-up of 5.3 yrs (range, 6 months-15.3 yrs). Event-free survivals were determined using the Kaplan-Meier method. RESULTS: Hospital mortality was 6.2% (4/65) and the complication rate was 18.5% (12/65). The freedom from late valve related mortality and morbidity at 5, 10 and 15 years was 86+/-5.5%, 81.9+/-6.8%, and 81.9+/-6.8% respectively. One valve related complication was due to the tricuspid valve. At last follow-up, 87% (47/54) of the survivors were in NYHA class I-II. CONCLUSIONS: With a conservative policy of tricuspid valve intervention, functional results of this patient population are good and long-term valve related morbidity and mortality are mainly related to the mitral and aortic valve procedures.

Adult↗
PubMed1992

[A 12-year clinical experience of cardiac valve replacement with domestic tilting disc valve prostheses in 1013 cases].

1013 patients with cardiac valve replacement during a 12-year period from 1978 to 1990 were reported. 566 cases were implanted with Shanghai-made tilting disc valve prostheses and 447 with Lanzhou-made (C-L valves). Mitral valve replacement (MVR) in 753 patients, aortic valve replacement (AVR) in 102 and double valves replacement (DVR) in 158. The overall early mortality rate was 6.2% with 4.9%, 7.8% and 11.3% after MVR, AVR and DVR respectively. Follow-up study was made in 3097.43 patient-year (mean 3.26 years). The late death rate was 1.6% patient-years and with 1.4, 1.8 and 3.2 after MVR, AVR and DVR respectively. The incidence of late valve-related complication (% patient-years) were: thromboembolism 0.39, anticoagulant-related hemorrhages 0.77, prostheses failure 0.22, prosthetic valve endocarditis 0.38, periprosthetic leak 0.12, and reoperations 0.38. The domestic tilting disc valve prostheses are considered to be qualified valves with low mortality and satisfactory results.

Adolescent↗
PubMed1993

Excellent long-term results of cardiac valve replacement with the St Jude Medical valve prosthesis.

BACKGROUND: A retrospective review of the performance of the St Jude Medical valve prosthesis over a 12-year period was undertaken. METHODS AND RESULTS: Between 1978 and 1990, 696 St Jude Medical valve prostheses (351 isolated aortic, 191 isolated mitral, 64 double aortic/mitral) were implanted into 616 patients (mean age, 55 years). Concomitant coronary artery graft surgery was performed in 18%. During mid-1991, follow-up was conducted, yielding a 97% completion (16 lost), for a total of 3075 cumulative patient-years (mean, 5.0 years). Early (30-day) mortality rates were 3.1%, 5.2%, and 6.4% after aortic, mitral, and double valve replacements, respectively. The 5-year actuarial survival rates were 94.1 +/- 1.3%, 85.8 +/- 2.7%, and 86.3 +/- 4.6% and those for 10 years were 89.6 +/- 1.9%, 72.9 +/- 6.1%, and 83.0 +/- 5.4%, respectively. There were no structural valve failures. Anticoagulant-related hemorrhage was the most common valve-related complication (28 events, 0.9% per patient-year), with three being fatal. Thromboembolism (13 events) occurred at a rate of 0.5% per patient-year (0.6% aortic, 0.3% mitral, 0.3% double). All of the nonstructural deteriorations (10 events, 0.3% per patient-year) were paravalvular leaks, including 3 aortic valve replacements in patients who developed hemolytic anemia. There was 1 valve thrombosis (0.03% per patient-year). Patients undergoing coronary artery graft surgery had lower survival and higher complication rates than patients without coronary artery graft surgery. There was a significant improvement (P < .001) in New York Heart Association functional class for the entire patient population. CONCLUSIONS: The St Jude Medical valve prosthesis has performed well in all positions over a 12-year period, with an acceptably low incidence of valve-related complications.

Aortic Valve↗
PubMed2004

Valve-sparing aortic root replacement in bicuspid aortic valves: a reasonable option?

OBJECTIVES: Aortic dilatation occurs in many patients with bicuspid aortic valves. We have added root replacement using the remodeling technique originally designed for tricuspid aortic valves to bicuspid aortic valve repair for treatment of the dilated root. We compared the results of remodeling in bicuspid aortic valves with those in tricuspid aortic valves. METHODS: From October 1995 through January 2004, 60 patients underwent root remodeling for bicuspid aortic valves (group A), and 130 patients underwent root remodeling for tricuspid aortic valves (group B). Correction of cusp prolapse was more often performed in group A (group A, 50/60; group B, 47/130; P < .0001). Transthoracic echocardiography was performed at 1 week, 6 and 12 months, and every year thereafter. Cumulative follow-up was 527 patient-years (mean, 2.9 +/- 2 years). RESULTS: No patient died in group A. Hospital mortality in group B was 5% (5/100; 95% confidence interval,1.6%-11.3%) after elective operations and 10% (3/30; 95% confidence interval, 2.1%-26.5%) after emergency operations. Mean systolic gradients were identical at 1 year (group A, 4.8 +/- 2.1 mm Hg; group B, 4.0 +/- 2 mm Hg) and 5 years (group A, 4.5 +/- 2.3 mm Hg; group B, 3.9 +/- 2.2 mm Hg). Freedom from aortic regurgitation of grade 2 or higher at 5 years was 96% in group A and 83% in group B ( P = .07), and freedom from reoperation at 5 years was 98% in group A and 98% in group B ( P = .73). CONCLUSIONS: Valve-sparing aortic replacement with root remodeling can be applied to aortic dilatation and a regurgitant bicuspid aortic valve. Hemodynamic function and valve stability of a repaired bicuspid aortic valve are comparable with those seen in cases of tricuspid anatomy.

Actuarial Analysis↗
PubMed1998

Allograft heart valve viability and valve-processing variables.

BACKGROUND: The impact of allograft valve viability on valve durability remains controversial. Analyses of our clinical results have demonstrated the superiority of the cryopreserved valve viable at the time of implantation over the 4 degrees C stored valve nonviable at the time of implantation. In this study, we quantitatively assessed the effects on viability of current and past valve-processing protocols at The Prince Charles Hospital. METHODS: The viability of pulmonary valves was quantitatively analyzed by thin-layer autoradiography to assess the effects of donor type, antibiotics, and valve storage. RESULTS: Control valve segments obtained from beating-heart donor valves had a higher initial viability (0.92+/-0.02) than nonbeating-heart donor valves (0.66+/-0.03). Cryopreservation after low-dose antibiotic sterilization significantly reduced viability to 50% to 60% of the control, and in the presence of amphotericin B, viability dropped further to 10% to 36% of the control. After 7 days' storage at 4 degrees C, viability was reduced to 2% of control and to 0% viability after 21 days. CONCLUSIONS: For maximal preimplantation viability, valves should be procured as soon as possible after cessation of heart beat and should be cryopreserved if they are not to be clinically implanted within 1 to 2 days. Amphotericin B should not be used in conjunction with cryopreservation if viability is to be maximized.

Amphotericin B↗
PubMed1979

Long term performance of 580 homograft and autograft valves used for aortic valve replacement.

Homograft valves have been used at the National Heart Hospital since 1964, and autograft valves since 1967. The homografts were treated either by freeze drying, by flash freezing, or by tissue maintenance in a nutrient medium (fresh). In order to compare these three groups of homograft valves with the autograft valves some long term assessment of valve function was required. In the whole group of 580 valves there have been 40 late deaths, which is a probability of only 7% over 6 to 14 years. Homografts and autografts are therefore excellent valves in terms of patient survival. Thromboembolism, haemolysis and bleeding may be regarded as complications which do not occur with homograft and autograft valves. There was one thrombogenic episode in this group, an incidence of one per 11,994 patient years and a probability of only 0.000083 patient years. Potentially fatal hazards of late complications with homoor autograft valves decrease with time and at this time is a negligible factor. The similarity in pattern of onset of late infections and degeneration probably reflects the greater susceptibility to infection of a degenerating valve. All three groups of homografts are very similar and differ only from the excellent performance of the autograft valves.

Aortic Valve↗
PubMed1995

Comparison of porcine biological valves with pericardial valves--a 12-year clinical experience with 1123 bio-prostheses.

In order to evaluate selective differences of biological porcine valves versus pericardial valves and to analyze various valve models, 8 different bioprostheses (4 porcine valves, 4 pericardial valves) were studied in a 12-year follow-up. From 1978 to 1990, 476 porcine bioprostheses (Carpentier-Edwards: n = 104, Carpentier Edwards Supraanular: n = 59, Hancock I: n = 41, Hancock II: n = 272) and 647 pericardial valves (Hancock-Extracorporeal: n = 479, Ionescu-Shiley: n = 76, Carpentier-Edwards: n = 57, Mitroflow: n = 35) were implanted. At time of implantation, the patient age ranged from 21-85 years, mean 57.1 +/- 12.4 years. 831 patients were analyzed in the long-term follow-up (62.3 +/- 18.6 months, cumulative follow-up of 6632 patient-years). The incidences of thromboembolic complications (TE), endocarditis (E), primary tissue failure (PTF), rate of reoperation (ReOp), and late mortality due to prosthesis dysfunction were analyzed, calculated, and compared within the different valve models (actuarial data, chi 2 test, log rank analysis). The incidences of TE and E were lower for pericardial valves when compared with porcine bioprostheses (TE: 0.88 vs. 1.8%/patient year; E: 0.24 vs. 0.5%/patient year); within the 2 groups, the different valve models did not show any major differences. However, the incidence of PTF was significantly higher in the pericardial valve group, being 36 +/- 6.5%, 68 +/- 10% and 86 +/- 19.5% after 6, 8, and 10 years; the respective figures for the porcine valves were 6 +/- 3.5%, 18 +/- 7.1%, and 60 +/- 13.1% (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Reversed offsetting of the septal attachments of the atrioventricular valves and Ebstein's malformation of the morphologically mitral valve.

Ebstein's anomaly of the tricuspid valve is characterised by downstream displacement of the tricuspid leaflets. In the case of the septal leaflet, the result is exaggerated offsetting of the atrioventricular valves. Thus it might be supposed that in Ebstein's anomaly of the mitral valve, downstream displacement of the aortic (septal) leaflet of the mitral valve could move its attachment beyond that of the tricuspid valve, resulting in reversed offsetting. To examine this hypothesis three patients each with a concordant atrioventricular connection were studied. The first, with Marfan's syndrome and without an abnormal mitral valve, had reversed offsetting shown by echocardiography. The second, without Marfan's syndrome and with Ebstein's anomaly of the mitral valve, showed echocardiographically normal offsetting but a displaced mural leaflet. The third, in whom Ebstein's anomaly of the mitral valve was confirmed at necropsy, showed all the features of the second case, with normal offsetting of the atrioventricular valves. Thus reversed offsetting is not a feature of Ebstein's anomaly of the mitral valve and in the first case this feature was caused by upward displacement of the tricuspid valve secondary to dilation of the aortic root.

Abnormalities, Multiple↗
PubMed1991

[Hydrodynamic in vitro comparison of a new artificial heart valve with the Björk-Shiley valve (standard)].

Measurements performed to compare a newly developed tilting disc valve with the Björk-Shiley valve included velocity profiles downstream of the heart valves, valve-induced flow turbulence and pressure drop across the opened valves. The velocity profiles measured with pulsed Doppler ultrasound are similar, although they do not permit a quantitative comparison of the valves. The interpretation of the 90 degrees-component of Doppler signals as a measure of the turbulence permits a quantitative comparison without the need for extensive measurements. However, only large vortices are recorded, so that our turbulent shear stresses are lower than these reported in the literature. The pressure drop across the opened valve is a measure of the energy loss, and important parameters for the valve can be derived from it. The pressure drop is dependent on the test conditions, and is therefore not a characteristic constant of the valve. The transformation of the power law Q = C delta P beta into a relation between Re- and Eu-number gives a nondimensional similarity number that is characteristic for tilting disc valves. Its verification requires more investigations, involving variation of valve size and the viscosity of the test fluid.

Blood Flow Velocity↗
PubMed2003

Tricuspid valve biopsy: a potential source of cardiac myofibroblast cells for tissue-engineered cardiac valves.

BACKGROUND AND AIMS OF THE STUDY: As progress is made in the development of a tissue-engineered cardiac valve, the need for a reliable cell source is particularly important. A technique has been developed for the reliable biopsy of tricuspid valve leaflets. Expanding the harvested cells in culture is feasible and provides a source of leaflet cells that are structurally and functionally similar to the pulmonary and aortic valve leaflet cells that they may replace. METHODS: Thirteen sheep underwent tricuspid valve biopsy. Transthoracic echocardiography (TTE) was performed to evaluate function and guide the subsequent biopsy. Myofibroblasts were isolated from the biopsy samples, expanded in culture through 10 passages, and evaluated with immunocytochemistry for valve cell markers. Two animals were sacrificed acutely, two animals died during the immediate postoperative period, and nine animals survived for four weeks or more. RESULTS: All preoperative and pre-explantation echocardiograms were normal. Both animals sacrificed acutely showed that the tricuspid valve leaflet was indeed biopsied with this technique. Two perioperative deaths occurred; one animal died secondary to injury of the chorda tendinea with subsequent destruction of the posterior leaflet; another died from disruption of the superior vena cava that led to irreversible cardiac tamponade. At sacrifice (2 to 17 weeks), all other animals showed intact tricuspid valves with normal leaflet anatomy. All cultured biopsies generated myofibroblasts that were immunocytochemically positive for alpha smooth muscle actin, chondroitin sulfate, vimentin and fibronectin. CONCLUSION: Biopsy of the tricuspid valve to obtain recipient cardiac valve leaflet cells is possible, and the technique is simple and reliable. Biopsy of the leaflet does not compromise function. Interstitial cells can be harvested and expanded in culture. Cellular structure and function is preserved and is similar to that of other cardiac leaflet cells. Tricuspid valve leaflet biopsies are a potential source for harvesting cells to be used in the development of a tissue-engineered cardiac valve.

Actins↗
PubMed1993

Catheter-implanted prosthetic heart valves. Transluminal catheter implantation of a new expandable artificial heart valve in the descending thoracic aorta in isolated vessels and closed chest pigs.

A new expandable artificial heart valve was developed for implantation by a transluminal catheter technique without using thoracotomy or extracorporeal circulation. The aim of this study was to implant the valve in isolated vessels of the descending thoracic aorta as well as in closed chest pigs, and furthermore to study the prosthesis' mechanical stability and the valve function. The artificial valve was made by mounting a porcine aortic valve on an expandable stent. Before implantation, the stent-valve was compressed on a deflated balloon catheter and mounted inside an introducer sheath. After intravascular introduction to the descending thoracic aorta the stent-valve was discharged from the sheath. Implantation was performed by balloon inflation which expanded the stent-valve to a diameter exceeding the internal vessel's diameter. After balloon deflation the stent-valve maintained an expanded configuration ensuring a stable fixation against the vessel wall. In vitro implantations were performed in 36 isolated descending thoracic aorta specimens obtained from 80 kg pigs. Mechanical stability was evaluated by applying a downing load to the prosthesis. No displacement occurred at loads < or = 1 kg when a large balloon (31 mm) was used for implantation. Transvalvular pressure differences between 11-47 mmHg (median) were obtained at antegrade flowrates between 5-8 l/min. Furthermore, only moderate leakage flows were measured during retrograde perfusion. In vivo implantations were performed in six 80 kg pigs. Implantation was safe and easy, and angiograph and haemodynamic evaluations revealed essentially no stenosis or regurgitation. No complications in migration, perforation, hemorrhage or thrombosis were observed. This study indicates a good mechanical stability and valve function of the new expandable artificial valves.

Animals↗