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At least 217 records · Page 12Linked to original sources

PubMed1996

[Analysis for 13 term deliveries after cardiac valve replacement and percutaneous transluminal mitral commissuroplasty].

OBJECTIVE: To study the cardiac function, mode of delivery and anticoagulant therapy in 13 pregnant women after cardiac valves replacement (CVR) and percutaneous transluminal mitral commissuroplasty (PTMC). METHOD: Retrospective data analysis. RESULTS: Patients with cardiac function of degree I to III can accomplish pregnancy and delivery safely after cardiac operation one and a half years. Using warfarin during pregnancy and delivery safely. Using warfarin during pregnancy and heparin during delivery did not increase the blood loss in both mothers and neonates, and congenital malformation either. It is more appropriate for pregnant women who had CVR to deliver by cesarean section and those who had PTMC to deliver vaginally. CONCLUSIONS: Women after cardiac operation can accomplish pregnancy and delivery if their cardiac function belong to degree I-III with or without digoxin treatment before delivery. Using anticoagulant therapy correctly according to prothrombin time (PT) test during pregnancy does not increase delivery complications to both mothers and neonates.

Adult↗

PubMed1991

Doppler-derived velocity of blood flow across the cardiac valves in the normal dog.

Doppler echocardiography is a relatively new procedure used to assess certain cardiovascular disorders in the dog. The objectives of this study were to determine the range of values for the maximal peak velocity of blood flow across each of the four cardiac valves in a sample population of normal adult dogs, using duplex continuous wave Doppler echocardiography, and to determine the optimal tomographic planes to use for an adequate continuous wave Doppler evaluation of the canine heart. Twenty normal dogs were examined to obtain values for peak transvalvular velocity for each of the four cardiac valves. The mean values +/- 1 SD, in cm/s were: 98.1 +/- 9.4 for the pulmonary valve imaged from the left side of the chest, 95.5 +/- 10.3 for the pulmonary valve imaged from the right side of the chest (n = 19), 118.1 +/- 10.8 for the aortic valve, 86.2 +/- 9.5 for the mitral valve and 68.9 +/- 8.4 for the tricuspid valve. Regurgitation was detected across the pulmonic valve in 14 of the 20 dogs, and across the tricuspid valve in ten dogs. The analysis of the tomographic images confirmed that for a complete assessment of a given intracardiac valve, the valve must be examined from all possible directions to obtain maximum values for peak velocity.

Animals↗

PubMed2004

Evaluation of intravascular hemolysis with erythrocyte creatine in patients with cardiac valve prostheses.

STUDY OBJECTIVES: To detect intravascular hemolysis in patients with cardiac valve prostheses. Erythrocyte creatine, a marker of erythrocyte age that increases with shortening erythrocyte survival, was evaluated with other hemolytic markers and hemodynamic parameters. DESIGN: Prospective study. PATIENTS AND MEASUREMENTS: Erythrocyte creatine was enzymatically assayed in 33 patients with prosthetic valves, including 15 patients with aortic valve replacement, 13 patients with mitral valve replacement, and 5 patients with double-valve (aortic and mitral) replacement, and 33 control subjects. Blood flow velocity and valvular regurgitation were determined by Doppler echocardiography. Other hemolytic markers (lactate dehydrogenase [LDH], reticulocyte count, and haptoglobin) and cardiac muscle markers (myoglobin and myosin light chain 1) were also measured. RESULTS: Erythrocyte creatine and LDH levels were significantly higher (p < 0.0001) and the haptoglobin level was lower (p < 0.0001) in patients with a prosthetic valve as compared with control subjects. However, there were no significant differences in these markers between those with (n = 17) and without (n = 16) regurgitation. Patients with high erythrocyte creatine levels (> 1.8 micro mol/g hemoglobin) exhibited significantly higher total peak flow velocity (sum of peak flow velocities at mitral and aortic valves) than those with normal erythrocyte creatine levels (p = 0.006). Erythrocyte creatine had a significant correlation with total peak flow velocity (r = 0.64, p < 0.0001), but LDH and haptoglobin had no significant correlation with total peak flow velocity. Patients with high LDH levels (> 460 IU/L) showed significantly higher myoglobin (p = 0.008) and myosin light chain 1 (p = 0.02) than those with normal LDH levels, whereas erythrocyte creatine was not related to cardiac muscle markers. CONCLUSIONS: Erythrocyte creatine is a quantitative and reliable marker for intravascular hemolysis in patients with prosthetic valves. Mild hemolysis is ascribable to valvular flow velocity rather than regurgitation.

Aged↗

PubMed1981

Cardiac valve replacement in the elderly: a review of 320 consecutive cases.

Cardiac valve replacement in 320 consecutive elderly patients (age 65 years and older) was examined retrospectively to determine the results of valvular replacement. From January 1966 to August 1979, 336 valve prostheses (146 mechanical and 190 porcine) were implanted in 320 patients (mean age 68.9 years, range 65-85 years). There were 190 aortic valve replacements (AVR), 116 mitral replacements (MVR) and 16 multiple valve replacements (MR). There were 178 patients ages 65-69 years, 114 patients ages 70-74 years, and 28 patients ages 75 years and older. Twenty (6.3%) had had previous cardiac surgery. Aortocoronary bypass was performed in 59 (18.4%). Twenty-eight patients (8.75%) died in the hospital (AVR 4.7%, MVR 11.4%, MR 37.5%). The mean follow-up was 30.2 months (total 735 patient-years). There were 92 late deaths, or 12.5% per patient year (AVR 11.3%, MVR 14.9%, MR 20.0%). Actuarial survival for all patients at 5 years was 49 +/- 7.6% (AVR 56 +/- 9.7%, MVR 47 +/- 12.5%). Survival at 24 months was 72 +/- 6.3% for ages 65-69 years, 66 +/- 9.2% for ages 70-74 years and 81 +/- 16% for patients 75 years and older. Valve-related complications were infective endocarditis (three mechanical and five porcine), periprosthetic leak (five mechanical and one porcine), valve dysfunction (12 mechanical) and thromboembolism (18 mechanical and seven porcine). At follow-up, 93.2% of surviving patients were in New York Heart Association functional class I or II.

Aged↗

PubMed1982

Comparison of noninvasive techniques in evaluation of the nontissue cardiac valve prosthesis.

The ability of bedside auscultation, echophonocardiography and cinefluoroscopy to detect prosthetic valve malfunction was compared in 81 patients with a Bjork-Shiley aortic or mitral valve prosthesis or a Beall mitral valve prosthesis. In 32 patients with an abnormal mitral valve prosthesis proved by cardiac catheterization, the sensitivities of auscultation, echophonocardiography and cinefluoroscopy were 94, 78 and 88 percent, respectively. In 25 patients with a normal mitral valve prosthesis, the specificities were 96, 64 and 89 percent, respectively. Twelve patients had an abnormal aortic valve prosthesis; the sensitivities of auscultation, echophonocardiography and cinefluoroscopy were 92, 58 and 33 percent, respectively. In 12 patients with a normal aortic valve prosthesis, the specificities were 100, 75 and 92 percent, respectively. Auscultation can detect almost all cases of malfunction of nontissue prosthetic valves. Echophonocardiography and cinefluoroscopy can detect most cases of malfunction of mitral valve prostheses, but false positive studies are common; both procedures are less useful in detecting malfunction of aortic valve prostheses.

Aortic Valve↗

PubMed1998

Acute myocardial beta-adrenergic receptor dysfunction after cardiopulmonary bypass in patients with cardiac valve disease. Duke Heart Center Perioperative Desensitization Group.

BACKGROUND: Patients with cardiac valve disease (CVD) frequently have congestive heart failure (CHF) and chronic myocardial beta-adrenergic receptor (beta AR) desensitization. Cardiac surgery requiring cardiopulmonary bypass (CPB) is associated with increased plasma catecholamine concentrations, which might worsen myocardial beta AR function. We therefore tested the hypothesis that acute beta AR dysfunction occurs during CPB in patients with CVD. METHODS AND RESULTS: After informed consent, 50 patients were enrolled. Right atrial biopsy samples were obtained at initiation and conclusion of CPB to assess beta AR density and adenylyl cyclase (AC) activity. Plasma catecholamine concentrations increased 3-fold during CPB (P < 0.01). Although beta AR density remained constant, isoproterenol-stimulated AC activity decreased significantly (approximately 30%; P < 0.005). AC activity decreased 22% and 24% with direct G protein (NaF) or AC (manganese) activation, respectively. Patients with or without preoperative CHF exhibited similar degrees of acute myocardial beta AR dysfunction during CPB. CONCLUSIONS: Acute myocardial beta AR dysfunction occurs during CPB in patients with severe CVD requiring surgical correction, with or without preexisting CHF. The primary underlying mechanism involves functional uncoupling of the beta AR signal transduction pathway at the level of the AC moiety. This information should facilitate development of agents designed to prevent acute myocardial beta AR dysfunction during CPB, potentially leading to improved outcome in this high-risk population.

Aged↗

PubMed1997

Freeze drying of cardiac valves in preparation for cellular repopulation.

When freeze-dried cardiac valves have been implanted they remained acellular. This study is the initial step in the development of a method designed to repopulate the substance of the freeze-dried valve with fibroblasts and the lumenal surface with endothelial cells. In this scheme, the freeze-drying process performs three functions; it provides a porous matrix, it kills the donor cells, and it preserves the collagen structure and hence the mechanical strength of the valve. This paper describes the production of appropriate porosity in freeze-dried porcine pulmonary valve leaflets. We found that Tg' for this material is -83 degrees C, which made it impracticable to freeze-dry exclusively from the glassy state. Uncontrolled freeze-drying produced a variable structure with most of the pores considerably smaller than the desired size and a dense layer, apparently devoid of perforations, on the surface. Compacted layers also occurred within the substance of the leaflets. These appearances suggested that extensive collapse had occurred during the drying process. Variation of the cooling rate, the primary drying temperature, and the warming rate during secondary drying enabled us to identify the following conditions that provided satisfactory internal porosity: cooling at 5 degrees C/min, vacuum drying for 6 h at -20 degrees C, and secondary drying for 10 h during rewarming at 0.06-0.08 degrees C/min. The internal cavities measured 100-350 microns2 by ca. 400 microns2, which is adequate to provide access for the fibroblasts (cross-sectional area ca. 150-200 microns2 when rounded but fusiform when attached. However, the internal porous structure rarely communicated with the surface and mechanical perforation was required to provide continuity between the surface and the internal sponge. The resulting method provides a basis for studies of cell colonization.

Animals↗

PubMed1982

Assessment and comparison of the performance of cardiac valves.

A statistical method is presented to assess and compare cardiac valve performances. Patient survival and valve performances have been separated, and valve function and malfunction have been described in comprehensive and comparable terms. Formulas are proposed to calculate the significance of the difference between two survival probabilities as well as to calculate the instantaneous rate of events and the median remaining lifetime.

Actuarial Analysis↗

PubMed1990

Postinflammatory scarring of cardiac valves of rheumatic and nonrheumatic etiology.

In rheumatic heart disease, cardiac valves often display only a nonspecific postinflammatory scarring, without specific features, such as the rheumatic granuloma. Fifty-five native valves excised from 47 patients, exhibiting postinflammatory scarring, were studied. Patients were subdivided into three groups according to their case histories: patients with both streptococcal infection and rheumatic fever (group I), with streptococdal infection without noncardiac major manifestations of rheumatic fever (group II), and without either of these features (group III). Pathological examination alone was unable to differentiate among the three groups, all the valves showing the same general pathological features. Differences in terms of sex, age, and valvular involvement were detected among group III and the others, whereas patients belonging to the first two groups did not differ significantly. These results suggest that diagnostic criteria for rheumatic fever are too restrictive and that a postinflammatory valvular scarring of nonrheumatic etiology does exist.

Aortic Valve↗

PubMed2004

Shear stress-induced upregulation of connexin 43 expression in endothelial cells on upstream surfaces of rat cardiac valves.

Endothelial expression of the gap junction proteins, connexin (Cx) 37, Cx40, and Cx43, varies within the vascular network. While previous studies suggest that shear stress may upregulate Cx43, it is not well understood if shear stress affects the expression of all endothelial connexins and to what extent. Endothelial cells on the upstream and downstream surfaces of cardiac valves are subjected to considerably different intensities of shear stress. We therefore reasoned that we could determine the extent hemodynamic forces affect the expression of Cx37, Cx40, and Cx43 by comparing their immunohistochemical distribution on the upstream and downstream surfaces of rat cardiac valves. We found 70- to 200-fold greater expression of Cx43 in the endothelial cells on the upstream than on the downstream surfaces. However, Cx37 was expressed almost equally in the endothelial cells on upstream and downstream surfaces, and Cx40, a major connexin in most vascular endothelial cells, was not detected on either surface. In addition to the heterogeneity in Cx43 expression, endothelial cells on the upstream surface were 35% to 65% smaller than those on the corresponding downstream surface. These results suggest that shear stress may affect endothelial cell size and Cx43 expression but not Cx37 expression.

Animals↗

PubMed2000

Tumors of the cardiac valves: imaging findings in magnetic resonance imaging, electron beam computed tomography, and echocardiography.

We describe the findings from various cross-sectional imaging modalities in patients with cardiac valve adherent masses. The techniques are discussed, and imaging findings are compared with the results of cardiac surgery. All three patients had neurological symptoms and/or cardiac murmurs. Transthoracic and/or transesophageal echocardiography revealed the cardiac mass in all three. For differentiation of thrombus and cardiac neoplasm magnetic resonance imaging (MRI) was also performed in all three patients and electron-beam computed tomography (EBCT) in two. Fast segmented cine gradient-echo MRI techniques provided mass depiction in all patients, while T1-weighted spin-echo imaging failed in mass detection in one patient. None of the patients showed evidence of valve regurgitation or stenosis in flow sensitive cine MRI. EBCT excluded mass calcifications in both patients and reliably demonstrated the valve attached lesions. Although echocardiography is the modality of choice in evaluating cardiac masses and especially valve attached masses, MRI and EBCT provide additional information about tissue characteristics and allows an excellent overview of the cardiac and paracardiac morphology. Fast segmented cine gradient-echo MRI is especially able to depict even small tumors attached to rapidly moving cardiac valves, and valve competence can be easily assessed within the same examination.

Adult↗

PubMed1983

Exercise capacity before and after cardiac valve surgery.

Exercise stress testing and right-heart catheterization were carried out in 131 patients before and 6 months after cardiac valve surgery. The exercise capacity increased only a little in patients with mitral or double-valve surgery. In contrast, most patients with an aortic valve replacement had good exercise performance after surgery. Corresponding to the reduced exercise capacity most of the patients also had disturbed hemodynamics after surgery, with an elevated mean pulmonary artery pressure at rest, that raised inappropriately during exercise, and a diminished cardiac output at rest, that failed to increase during exercise, in relation to oxygen uptake.

Adult↗

PubMed1992

Regurgitant flow in cardiac valve prostheses: diagnostic value of gradient echo nuclear magnetic resonance imaging in reference to transesophageal two-dimensional color Doppler echocardiography.

Gradient echo nuclear magnetic resonance (NMR) imaging and transesophageal two-dimensional color Doppler echocardiography are flow-sensitive techniques that have been used in the diagnosis and grading of valvular regurgitation. To define the diagnostic value of gradient echo NMR imaging in the detection of regurgitant flow in cardiac valve prostheses and the differentiation of physiologic leakage flow from pathologic transvalvular or paravalvular leakage flow, 47 patients with 55 valve prostheses were examined. Color Doppler transesophageal echocardiography was used for comparison. Surgical confirmation of findings was obtained in 11 patients with 13 valve prostheses. Gradient echo NMR imaging showed regurgitant flow in 37 of 43 valves with a jet seen on transesophageal echocardiography and it detected physiologic leakage flow in 4 additional valves. There was 96% agreement between the two methods in distinguishing between physiologic and pathologic leakage flow. The methods differed on jet origin of pathologic leakage flow in six prostheses. The degree of regurgitation was graded by both NMR imaging and transesophageal echocardiography, according to the area of the regurgitant jet visualized; gradings were identical for 75% of valve prostheses. Quantification of jet length and area showed a good correlation between the two methods (r = 0.85 and r = 0.91, respectively). Gradient echo NMR imaging is a useful noninvasive technique for the detection, localization and estimation of regurgitant flow in cardiac valve prostheses. However, because transesophageal echocardiography is less time-consuming and less expensive, gradient echo NMR imaging is unlikely to displace transesophageal echocardiography and should be used only in the occasional patient who cannot be adequately imaged by echocardiography.

Coronary Circulation↗

PubMed1980

[Flow through various cardiac valves prostheses (author's transl)].

We have studied the flow through various cardiac valves prostheses, with the assistance of an artificial left ventricular pump. We took photographs during the whole of the cardiac cycle but we present here only the view of the middle systolic period. As regards the mechanics prostheses (Bjork-Shiley, Lillehei-Kaster, Saint-Jude-Medical, Starr-Edwards) the flow changes with the shape and opening of the valve. Biologic prostheses (Carpentier-Edwards, Hancock, Ionescu-Shiley) present an impertubated flow.

Biophysical Phenomena↗

PubMed2006

Vascular endothelial growth factor receptor signaling is required for cardiac valve formation in zebrafish.

Vascular endothelial growth factor-receptors (VEGF-Rs) are pivotal regulators of vascular development, but a specific role for these receptors in the formation of heart valves has not been identified. We took advantage of small molecule inhibitors of VEGF-R signaling and showed that blocking VEGF-R signaling with receptor selective tyrosine kinase inhibitors, PTK 787 and AAC 787, from 17-21 hr post-fertilization (hpf) in zebrafish embryos resulted in a functional and structural defect in cardiac valve development. Regurgitation of blood between the two chambers of the heart, as well as a loss of cell-restricted expression of the valve differentiation markers notch 1b and bone morphogenetic protein-4 (bmp-4), was readily apparent in treated embryos. In addition, microangiography revealed a loss of a definitive atrioventricular constriction in treated embryos. Taken together, these data demonstrate a novel function for VEGF-Rs in the endocardial endothelium of the developing cardiac valve.

Animals↗

PubMedDate not supplied

The role of cardiac valves in artificial heart performance.

The criteria for the design, selection of materials, and fabrication of a total artificial heart have evolved over several years. As these criteria have become more sophisticated and exact, they have optimized the performance of all components within the system. A pump with sufficient volume and pressure output that fits in the available anatomic space was a primary objective. Concomitantly, a nonthrombogenic, durable material that was nondegradable in body fluids was being developed. The most easily managed energy source selected to date has been pulsed, compressed air programmed for gentle but effective systole and diastole. The evolution of good cardiac valves has been of major importance to the artificial heart effort. The historical development of the artificial heart has often centered around existing prosthetic valves which are currently an integral component of the complete system. A detailed analysis of the performance of the total artificial heart clearly identifies the role of the cardiac valve.

Animals↗

PubMed2003

Primary cardiac valve tumors: early and late results of surgical treatment in 10 patients.

BACKGROUND: Our goal was to study the clinical characteristics of primary valve tumors and the late surgical results of their resection. METHODS: We reviewed our clinical experience with the surgical treatment of ten primary valve tumors at Fu Wai Hospital over the past 19 years. During that time, cardiac valve tumors accounted for 2.65% of all primary cardiac tumors at our hospital, and the incidence of primary valve tumors was roughly one in 4,000 cardiac operations. There were 5 male and 5 female patients aged 2 to 66 years (mean age, 30.1 years). The clinical presentation included exertional dyspnea in 7 patients, neurological symptoms in 2, and cyanosis at rest in 1 patient. The diagnosis was established by preoperative echocardiography in 8 patients, and in the other 2, it was confirmed by the findings at operation. All of the tumors were resected. Eight of the ten tumors were benign, and two were malignant. RESULTS: All patients survived the operation and recovered uneventfully. Late outcomes were known for all patients. There were three late deaths. One patient with a benign tricuspid valve tumor died 2 months postoperatively of an electrolyte disorder. The other 2 patients with a malignant mitral valve tumor died within 1 year postoperatively. The 7 survivors, all with a benign valve tumor, were followed for an average of 5.7 years (range, 8 months to 19 years), and all were in functional class I. Exercise tolerance improved to normal levels. The latest follow-up echocardiograms showed no evidence of local recurrence in any patient. CONCLUSIONS: Excellent early and late surgical results can be obtained in patients with benign valve tumors. The prognosis for patients with a malignant valve tumor is poor.

Adolescent↗

PubMed1987

Implantation of the Duromedics bileaflet cardiac valve prosthesis in 400 patients.

From September, 1983, to April, 1986, 451 Duromedics bileaflet cardiac valve prostheses were implanted in 400 patients at our institution in Vienna. Aortic valve replacement was done in 190 patients, 157 underwent mitral valve replacement (1 patient also underwent tricuspid valve replacement), 52 underwent double valve replacement, and 1 patient underwent isolated reoperation for tricuspid valve replacement. Concomitant procedures were performed in 86 patients (21.5%). Sixty-one patients (15.2%) had undergone previous cardiac surgery; 32 (8%) had undergone earlier valve replacement. The early mortality rate (within 30 days) was 6.25% (25 patients). Follow-up was done on 337 surviving Austrian citizens; this represents 429 patient-years. The late mortality rate was 2.1% per patient-year (9 patients). We observed paravalvular leak in 3 patients (0.7% per patient-year), thromboembolism in 4 (0.9%), prosthetic valve endocarditis in 5 (1.2%), and anticoagulant-related hemorrhage in 10 (2.3%). Valve failure occurred in 8 patients (1.8%). We conclude, therefore, that good clinical results and a low complication rate can be achieved with this new type of valve.

Anticoagulants↗