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PubMed1989

Pulsed holmium laser ablation of cardiac valves.

Ablation efficiency and residual thermal damage produced by pulsed holmium laser radiation were investigated in vitro for bovine mitral valves and human calcified and noncalcified cardiac valves. Low-OH quartz fibers (200 and 600 microns core diameter) were used in direct contact perpendicular to the specimen under saline or blood. Etch rate was measured with a linear motion transducer. Radiant exposure was varied from 0 to 3 kJ/cm2. For 200-microns fibers, the energy of ablation was approximately 5 kJ/cm3 in noncalcified and 15 kJ/cm3 in calcified valves. Etch rates were dependent on mechanical tissue properties. Maximum etch rate at 1,000 J/cm2 was 1-2 mm/pulse at 3 Hz repetition rate. Microscopic examination revealed a zone of thermal damage extending 300 microns lateral into adjacent tissue. Thermal damage was independent of radiant exposure beyond twice threshold.

Animals↗
PubMed2004

Can chronic poststernotomy pain after cardiac valve replacement be reduced using thoracic epidural analgesia?

BACKGROUND: The aim of our study was to evaluate the use of thoracic epidural analgesia (TEA) in acute pain management after cardiac valve replacement and determine if the incidence of chronic pain related to the sternotomy was reduced by the use of TEA. This patient group was chosen to exclude pain related to the use of the internal mammary artery and angina pectoris. METHODS: Patients scheduled for elective cardiac valve replacement were offered TEA. A match-control group was selected. Epidural catheter placement, complications and postoperative neurological state were noted for both groups. Eighteen months postoperatively, a questionnaire was sent out concerning pain management, wound discomfort and pain. RESULTS: Forty-nine patients were included. The TEA group consisted of 35 patients. At 18 months' follow up, 37% from the TEA group and 21% from the control group had pain or discomfort related to the sternum (NS). Two in the TEA group had severe pain. CONCLUSION: We found in our small material that TEA provided excellent analgesia in the peri- and postoperative period, but we did not find a protective effect of TEA on chronic poststernotomy pain, neither weak pain nor severe pain.

Adult↗
PubMed2003

Cardiac valves in patients with Q fever endocarditis: microbiological, molecular, and histologic studies.

The pathologic features of Q fever endocarditis, which is caused by Coxiella burnetii, were histologically evaluated in cardiac valves from 28 patients. We used quantitative image analysis to compare valvular fibrosis, calcifications, vegetations, inflammation, and vascularization due to Q fever endocarditis with that due to non-Q fever endocarditis and valvular degeneration. We also studied the presence of C. burnetii in valves by immunohistochemical analysis, culture, and polymerase chain reaction (PCR). Histologically, Q fever endocarditis was characterized by significant fibrosis and calcifications, slight inflammation and vascularization, and small or absent vegetations. Despite antibiotic treatment, non-statistically significant variations at the histologic level were observed. These pathologic features could be confused with noninfectious valvular degenerative damage. We found that the detection of C. burnetii in cardiac valves by immunohistochemical analysis, culture, and PCR decreased significantly only after 1 year of antibiotic treatment, which emphasizes the long persistence of this organism in valve tissues. Pathologic and immunohistochemical analyses may contribute to the diagnosis of Q fever endocarditis.

Adult↗
PubMed1988

Clinical and hemodynamic results of cardiac valve replacement with the Monostrut Björk-Shiley prosthesis.

Between May 1983 and April 1986, 318 patients underwent cardiac valve replacement with the Monostrut Björk-Shiley prosthesis. There were 136 aortic valve replacements, 128 mitral valve replacements, and 54 multiple replacements. A total of 373 valves were implanted. Associated procedures were done in 79 (25%) of the patients. Hospital (30-day) mortality rate was 5.6% (18 patients): 2.9% (n = 4) after aortic, 7.8% (n = 10) after mitrals and 7.4% (n = 4) after multiple valve replacement. Follow-up was obtained in all 300 operative survivors, for a total of 500 patient-years (mean 18 months). Actuarial survival rate, excluding operative deaths, at 4 years was 94.7% +/- 1.5% (mean +/- standard error of the mean). There were 16 thromboembolic episodes (3.2/100 patient-years). Freedom from all valve-related complications was 87% +/- 2.4% at 3 1/2 years. Neither valve thrombosis nor structural failure has been observed. Eighty percent of the patients are in New York Heart Association functional class I. Forty-two patients (26 with aortic and 16 with mitral valve replacement) underwent cardiac catheterization a mean of 6 1/2 months after the operation. In the aortic position, peak gradients were an average of 6.9 +/- 1.2 mm Hg. Mean systolic gradients were 12.4 +/- 6.3 mm Hg and did not increase with exercise. In the mitral position, end-diastolic gradients were an average of 2.1 +/- 2 mm Hg and mean gradients, 5.9 +/- 2 mm Hg. Discharge coefficient (estimated orifice area/geometric area) was 0.63 +/- 0.2 for the aortic and 0.53 +/- 0.2 for the mitral prostheses. Disc opening was maximal in most patients. These results indicate that the Monostrut prosthesis has a low rate of thromboembolic events, no structural failures or thrombotic obstructions and excellent hemodynamic performance, especially in the small aortic sizes (discharge coefficient for 19 and 21 mm valves, 0.77).

Adolescent↗
PubMedDate not supplied

Paraprosthetic leak: a complication of cardiac valve replacement.

Paraprosthetic leak (PPL) is a rare but potentially serious complication of cardiac valve replacement. Between 1974 and 1988, 1175 prosthetic valves were implanted in 1026 patients by one cardiac surgeon at St. Thomas' Hospital, London. Of these 539 (52.5%) were aortic (AVR), 334 (32.6%) mitral (MVR), 7 (0.7%) tricuspid, and 144 (14%) AV and MV double valve replacements (DVR). There were only 2 triple valve replacements. The prosthetic valves implanted were the Starr-Edwards (7%), Bjork Shiley (11.8%), Lillehei-Kaster (23%), Carpentier-Edwards bioprosthesis (35.2%), Duromedics bileaflet (16.4%) and a variety of other mechanical and bioprosthetic valves (6.6%). Over the 15 year period there were a total of 82 (7%) valve failures of which PPL was diagnosed in 29 (2.5%) valves in 24 patients. Presenting features included cardiac decompensation in 72%, bacterial endocarditis in 12% and haemolytic anaemia in 12%. One patient (4%) had no symptoms. Nineteen patients underwent re-operation. Median time to re-operation was 15 months (range 1-65 months) with a re-operative mortality of 22%. Clinical evidence of prosthetic valve infection was found in 79% of MVR and 67% of AVR. A heavily calcified aortic annulus, found in 47% of patients, may also have contributed to PPL after AVR.

Aortic Valve↗
PubMed2005

In vitro ablation of cardiac valves using high-intensity focused ultrasound.

The purpose of this study was to evaluate the possibility of using high-intensity focused ultrasound (US), or HIFU, to create lesions in cardiac valves in vitro. Calf mitral valves and aortic valves were examined. Focused US energy was applied with an operating frequency of 4.67 MHz at a nominal acoustic power of 58 W for 0.2, 0.3 and 0.4 s at 4-s intervals. Mitral valve perforation was achieved with 20.8 +/- 3.7 exposures of 0.2 s, 15.4 +/- 2.1 exposures of 0.3 s or 11.2 +/- 2.3 exposures of 0.4 s. Aortic valve perforation was achieved with 13.3 +/- 2.4 exposures of 0.2 s, 10.3 +/- 2.2 exposures of 0.3 s or 8.4 +/- 1.8 exposures of 0.4 s. The mean diameter of the perforated area was 1.09 +/- 0.11 mm. The lesions were slightly discolored and coagulation of tissue around the perforation was observed. HIFU was successful in perforating cardiac valves. With further refinement, HIFU may prove useful for valvulotomy or valvuloplasty.

Animals↗
PubMedDate not supplied

Comparison of three myofibroblast cell sources for the tissue engineering of cardiac valves.

The objective of this study was to evaluate the capacity of three clinically useful tissue sources: tricuspid valve leaflet (TVL), carotid artery (CA), and jugular vein (JV), to generate myofibroblasts for potential use in a tissue-engineered cardiac valve replacement. Tissue biopsies of clinically appropriate sizes obtained from juvenile sheep were used for this work. Cells obtained from all three tissue sources exhibited a myofibroblast phenotype in vitro, as demonstrated by their immunoreactivity with antibodies directed against vimentin, alpha-smooth muscle actin, fibronectin, and chondroitin sulfate. Protein synthesis characteristics were defined for the key extracellular matrix components: collagen, glycosaminoglycans, and elastin. Among the three sources, JV generated the highest numbers of cells, and JV cells produced the largest amount of collagen per cell. These data suggest that venous tissue, with its relative ease of accessibility, may generate myofibroblasts potentially useful for the interstitial cellular component of a tissue-engineered cardiac valve.

Actins↗
PubMed2004

Cardiac valves in patients with Whipple endocarditis: microbiological, molecular, quantitative histologic, and immunohistochemical studies of 5 patients.

The pathological features of Whipple endocarditis, which is caused by Tropheryma whipplei, were histologically evaluated in cardiac valves from 5 patients. We used quantitative image analysis to compare the valvular fibrosis, calcifications, vegetations, inflammation, and vascularization due to Whipple endocarditis with those due to non-Whipple endocarditis and degenerative valves. We also studied the presence of T. whipplei in valves by immunohistochemical analysis, culture, and polymerase chain reaction (PCR). In histologic analysis, Whipple endocarditis was characterized by significant fibrosis, a lack of calcifications, slight inflammation and vascularization, and vegetations of intermediate size. Inflammatory infiltrates consisted mainly of foamy macrophages and lymphocytes. We found that the detection of T. whipplei in cardiac valves, by immunohistochemical analysis, was correlated with the detection of the bacterium by culture and PCR. We report, for the first time, the immunodetection of T. whipplei in a surgically removed arterial embolus. Pathological and immunohistologic analyses may contribute to the diagnosis of Whipple endocarditis.

Adult↗
PubMedDate not supplied

CD117-positive cells and mast cells in adult human cardiac valves--observations and implications for the creation of bioengineered grafts.

BACKGROUND: There is no report to date of stem cells in human cardiac valves. We examined their possible presence, number, and distribution in valves removed at cardiac surgery from patients with a variety of underlying valve pathologies. METHODS: Grossly normal aortic and mitral valves were obtained from live heart transplant patients. Surgically excised valves with rheumatic mitral stenosis, aortic valve age-related degeneration, aortic valve changes of aortoannular ectasia, and mitral valves with myxomatous degeneration were studied. Immunohistochemical and histochemical studies were performed on sequential valve sections, including hematoxylin and eosin, hematoxylin phloxine saffron, Movat pentachrome, toluidine blue, CD31, CD34, and CD117. RESULTS: There were small clusters of CD117-positive cells in the fibrosa and spongiosa of mitral and aortic valves from all groups of valves. Sequential sectioning and staining showed that almost all of these cells were mast cells. However, in the mitral myxomatous valves and the mitral rheumatic valves, there were rare CD117-positive cells that did not have corresponding toluidine blue staining and thus could be valve mesenchymal stem cells. CONCLUSIONS: Most of the CD117-positive cells in normal and diseased adult heart valves are mast cells. These valve cells could play a role in valve pathology and injury. A very small number of possible valve stem cells were also identified. It is unlikely that these valve stem cells are sufficient in number to allow isolation and expansion for tissue engineering purposes.

Bioprosthesis↗
PubMed1991

Percutaneous fiberoptic angioscopy of the cardiac valves.

The feasibility of percutaneous translumial angioscopy of the cardiac valves was examined in eight patients with and in 11 patients without valvular disease. In eight of these patients, a guiding balloon catheter (9F) was introduced into the aortic root, a guide wire (0.014 or 0.025 inch) was introduced through the catheter into the left ventricle to prevent dislocation of the catheter, and a fiberscope (1.6 or 4.6F) was advanced to the distal tip of the catheter. The balloon was then inflated with carbon dioxide and was manipulated against the aortic valve; a body temperature heparinized saline was infused through the catheter for observation. Similarly, the balloon catheter was advanced transseptally into the left atrium for observation of the mitral valve in four patients. Also, the balloon catheter was advanced through the right femoral vein into the right atrium for observation of the tricupid valve in three patients. In patients with a normal aortic valve, the aortic cusp surface was smooth and white and the edges were sharp. They opened briskly during systole and coapted each other completely during diastole. In rheumatic aortic regurgitation, the cuspus were thick and blunt and their coaptation insufficiency was observed during diastole. In a patient with rheumatic AS, globular and yellow cusps were observed. Mitral valve leaflets were smooth and white in a patients without mitral valvular disease, while the leaflets were yellow, thick and irregular, and blood regurgitation from the left ventricle into the left atrium could be observed in two patients with rheumatic MSR. The process of opening and closure of a tricuspid valve was also observed in three patients without tricuspid valvular disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Cardiac valve replacement with glutaraldehyde preserved aortic allografts.

From September 1984 to December 1988, 144 patients underwent cardiac valve replacement using glutaraldehyde preserved stent mounted aortic allografts. The mean age was 21.4 years (54.9% were 15 years old or younger). The mitral valve was replaced in 125 patients, the aortic valve in 7, the pulmonary valve in 3, the tricuspid in 1, the mitral and tricuspid in 1, and the aortic and mitral in 7. Hospital mortality was 2.8% (4 patients). Total follow-up was 396.3 patient-years and the mean follow-up was 2.8 years per patient. The 5-year actuarial survival was 73.8% +/- 11.9%. The 4-year actuarial survival for patients aged 15 or younger was 81.4% +/- 7.1%. The overall mortality was 2.8% +/- 0.8%/per patient-year. The incidence of valve-related complications was 4.8% +/- 1.1%/per patient-year, and the calcification rate was 3.0% +/- 0.9%/per patient-year and was the main complication reported in 12 patients, all under the age of 15 years. It occurred 14-47 months after implantation (mean 32.7 months). Five-year actuarial freedom from valve dysfunction due to calcification was 82.6% +/- 5.0% and for patients aged 15 or younger was 69.9% +/- 8.8%. The incidence of reoperation was 3.3% +/- 0.9%/per patient-year. These initial results demonstrate a 5-year actuarial freedom from primary valve failure due to fibrocalcification superior to the results obtained with xenobioprostheses in the paediatric age group.

Actuarial Analysis↗
PubMed1990

Release of endothelium-derived relaxing factors from canine cardiac valves.

In the present study, the ability of intact cardiac valvular endothelial cells to release vasodilatory prostanoids and endothelium-derived relaxing factor was investigated. Endothelium-denuded canine coronary arteries were used for bioassay and contractile force recording. Insertion of small segments of cardiac valve (20-30 mm2) with intact endothelium into endothelium-denuded coronary arterial rings did not markedly alter the sensitivity nor magnitude of the coronary artery contractile response to KCl. In contrast, the prostaglandin F2 alpha (PGF2 alpha)-induced contraction was significantly depressed (70% decrease in magnitude and 216% increase in ED50), compared with contraction in the absence of valvular endothelium (5.52 +/- 0.49 g and ED50 of 1.18 +/- 0.02 microM, respectively). These alterations in PGF2 alpha-induced contractions were reduced to 38% decrease in magnitude and +66% in ED50 in the presence of 5 microM indomethacin. Addition of acetylcholine (0.1-30 microM) into these endothelium-denuded coronary artery/valve preparations resulted in a dose-dependent relaxation, reaching a maximum of -59.9 +/- 1.6% (mean +/- SEM of seven vessels). Preincubation of valvular endothelium with 5 microM indomethacin also reduced these acetylcholine-induced valvular endothelium-dependent relaxations to 40.4 +/- 5.5% (mean +/- SEM of 13 vessels). Addition of hemoglobin (3 microM) further attenuated relaxation to -16.0 +/- 7.7% (mean +/- SEM of 14 vessels), while superoxide dismutase (20 units/ml) potentiated the relaxant response to -81.3 +/- 9.4% (mean +/- SEM of 11 vessels) in the presence of indomethacin. These findings suggest that there is a continuous basal release of vasodilatory prostanoids and endothelium-derived relaxing factor from the valvular endothelium, which can be further stimulated with acetylcholine and superoxide dismutase, and inhibited by indomethacin and hemoglobin.

Acetylcholine↗
PubMed1987

[Morphology of infectious endocarditis affecting bioprostheses of the cardiac valves].

Four varieties of infectious endocarditis were identified after cardiac valve bioprostheses: early acute, early subacute, late acute, and late subacute forms. Any of these forms may be of bacterial, fungal, or mixed (bacterial and fungal) origin. In the early forms, the infection was of exogenous origin, with a predominance of Gram-positive organisms, whereas in the late forms it was endogenous with a preponderance of Gram-negative flora. The hallmarks of fungal thromboendocarditis were an early massive thrombosis of the bioprosthesis, multiple thromboembolism, and an absence of cellular reaction in the cuspal tissue. In the subacute bacterial endocarditis, progressive dysfunction of the bioprosthesis resulting from calcination of bacteria-containing cusps and thrombi was noted.

Aortic Valve↗
PubMed1985

Bioprostheses for cardiac valve replacement.

Biologic tissue has been used successfully for cardiac valve substitutes since the introduction of glutaraldehyde preservation in 1969. Assessment of the clinical performance of prosthetic valves requires consideration of thromboembolism, anticoagulant-related hemorrhage, prosthetic valve endocarditis, periprosthetic leak and prosthesis failure. Two methods of assessment of valve performance, linearized occurrence rates and multiple decrement analysis of valve-related complications, are illustrated in evaluation of previous and new-generation Carpentier-Edwards porcine bioprostheses. The standard valve has a valve-related complication rate of 2.9% per patient-year over 5 years, while the rate for the new-generation supra-annular prosthesis is 4.3% per patient-year in the 2-year interval. Thromboembolism has been 1.6% and 1.7% per patient-year, respectively, for the previous and new-generation prostheses. Primary tissue failure has occurred only in the standard prosthesis, 0.6% per patient-year. The freedom from all valve-related complications is 93.1% at 2 years and 87.5% at 6 years with the standard valve and 95.1% at 2 years with the new-generation prosthesis. Standardized assessment of prosthetic performance should provide physicians and surgeons with the knowledge to optimize patient management. The new-generation biologic prostheses with improved preservation should reduce calcification and fatigue lesions. Tissue valves have afforded patients an excellent quality of life with a low incidence of valve-related complications.

Bioprosthesis↗
PubMed1992

[Cardiac valve replacement in the elderly].

From January 1980 through December 1990, seventy one consecutive patients over 60 years of age (mean age 64 +/- 4 years) and 231 patients younger than 60 years underwent cardiac valve replacement procedures. In the elderly group, aortic valve replacement was performed in nineteen patients, mitral valve replacement in thirty-three patients both aortic and mitral valve replacement in sixteen patients, and both mitral and tricuspid valve replacement in three patients. Aortocoronary bypass was performed in four and tricuspid annuloplasty in 19 patients simultaneously. Two patients were operated on emergency. As for preoperative status, 63 patients (88.7%) were in New York Heart Association (NYHA) Functional Class III or IV. Mechanical valves were implanted in all aortic position and 16 mitral position. Bioprosthetic valves were placed in 34 mitral position and 3 tricuspid position. Mean follow-up period was 42 +/- 33 months. The early mortality rate was 11% (8 patients) and the actuarial survival rate was 88 +/- 5% at five years and 74 +/- 10% at ten years. Postoperative functional improvement was excellent in 85.7% of the survivors. In the younger age group, 77.9% belonged to NYHA class III or IV preoperatively. The early mortality was 3.0% (7 patients) and the actuarial survival rate was 95 +/- 2% at five years and 86 +/- 2% at ten years. And postoperatively 91.3% were in NYHA class I or II. In conclusion, cardiac valve replacement in the elderly can be performed with an acceptable mortality and excellent functional improvement.

Age Factors↗
PubMed2002

Human cardiac valve interstitial cells in collagen sponge: a biological three-dimensional matrix for tissue engineering.

BACKGROUND AND AIM OF STUDY: The use of a biological, biodegradable scaffold remodeled by cells to resemble a valve leaflet is an attractive approach to tissue engineering. The study aim was to evaluate the suitability of a three-dimensional biodegradable collagen sponge for maintenance of cell viability, proliferation and phenotype of cultured human cardiac valve interstitial cells (ICs). METHODS: Pieces of valve leaflets were snap-frozen, sectioned and stained by immunoperoxidase. Interstitial cells were cultured from cardiac valves and plated onto glass coverslips or seeded in collagen sponge, then stained by immunofluorescence or immunoperoxidase. A panel of antibodies was used to determine cell phenotype. Cell viability was assessed using a dye-based cell proliferation assay, and cell death by lactate dehydrogenase measurement. RESULTS: ICs variably expressing the phenotypic markers were found throughout the native valve leaflet, but particularly on the ventricular side. Cultured ICs either on coverslips or in collagen sponge expressed vimentin, a fibroblast surface antigen and variable amounts of smooth muscle (SM) alpha-actin. Expression of the other phenotypic markers, SM myosin, desmin and prolyl 4-hydroxylase differed: interestingly, the ratio of cells in collagen sponge expressing these markers reflected that found in the native valve leaflet. Confocal microscopy of ICs in the collagen sponge revealed the presence of cells with long interconnecting extensions indicating cell communication. Cell proliferation and cell death assays established that cells were not only viable after four weeks in the sponge, but were also proliferating. CONCLUSION: This study demonstrates that collagen sponge is a suitable biodegradable scaffold that can maintain viable valve ICs and appears to enhance the capacity of the cell to express its original phenotype.

Biological Products↗
PubMed1984

Factors influencing thromboembolic complications in Omniscience cardiac valve patients.

Clinical data were gathered over five years (650 patient-years) for all 155 aortic valve replacement, 125 mitral valve replacement and 46 double valve replacement patients implanted with the Omniscience cardiac valve prosthesis at three North American medical cent es. Mean age was 56 +/- 12 years, 80% were preoperatively in NYHA class III or IV, and 57% had previous or concomitant cardiac surgery. Data were evaluated for the incidence of thromboembolic complications. During the late postoperative period, transient ischaemic episodes occurred in six patients (0.92% per patient-year). The five-year actuarial thrombus-free rate for serious thromboembolic complications (valve thrombosis or thromboembolism with residual effects) for aortic valve replacement patients is 96% and 95% for mitral valve replacement patients. For patients experiencing any transient or serious thromboembolic complication, 35% had a compromise of coumadin anticoagulation shortly before the thromboembolic event, 60% had a history of atrial fibrillation, and 76% a history of rheumatic heart disease. Statistically, these rates are significantly higher compared with the original valve population. The low incidence of thromboembolic complications over this five-year clinical study demonstrates a commendable degree of safety and performance for the Omniscience valve.

Actuarial Analysis↗