Abnormal left ventricular blood flow patterns with mitral prostheses and aneurysm: analysis by two-dimensional Doppler-echocardiography.
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Adult↗
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Results for “Prosthesis Coloring”
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Endovascular conversion procedure for failed primary endovascular aortic stent-grafts.
Initial failure of successful deployment of endovascular aortic stent-grafts can be due to a variety of factors and frequently requires surgical intervention. We describe an endovascular technique for salvaging initially failed tubular aortic and bifurcated aortoiliac stent-grafts with reference to three cases.
Aged↗
Elbow joint contact study: comparison of techniques.
Elucidation of the contact areas between joint surfaces is important to both prosthetic design and the understanding of degeneration of articular cartilage. Numerous experimental methods are available to study joint contact, including cartilage staining, joint space casting, and pressure sensitive film techniques. This study attempts to compare the ability of each experimental technique to determine elbow joint contact. The silicone casting technique appears to be the best method to study joint contact area. The effects of magnitude and orientation of applied forces on the elbow joint contact patterns are studied.
Coloring Agents↗
Spray coloring of silicone elastomer maxillofacial prostheses.
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Color↗
Intrinsic color of isophorone polyurethane for maxillofacial prosthetics. Part II: Color stability.
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Color↗
Left atrial appendage function analyzed by tissue Doppler imaging in mitral stenosis: effect of afterload reduction after mitral valve commissurotomy.
BACKGROUND: This study sought to investigate the relative load dependence of left atrial appendage (LAA) tissue Doppler velocities in patients with mitral stenosis after percutaneous mechanical mitral commissurotomy (PMMC). METHODS: LAA tissue Doppler velocities were obtained in 34 patients with mitral stenosis (20 with sinus rhythm and 14 with atrial fibrillation) before and after PMMC by transesophageal echocardiography. Standard ultrasound studies were also performed for mitral valve orifice area, transmitral pressure gradient, and LAA blood flow velocity measurements. RESULTS: PMMC resulted in a significant increase in mitral valve area (P < .001) and decrease in mean transmitral pressure gradient (P < .001). LAA tissue Doppler velocities consisted of a triphasic velocity profile: SLAA and ELAA occurring during left ventricular contraction and relaxation, respectively, and ALAA occurring after the atrial contraction. After PMMC, ELAA and ALAA velocities consistently increased (4.8 +/- 1.2 to 7.9 +/- 2.6 cm/sec [P < .001] and 6.6 +/- 2.9 to 8.1 +/- 4.2 cm/sec [P < .05], respectively). The mean transmitral pressure gradient was significantly correlated with ALAA before and after PMMC (r = .65). CONCLUSIONS: In mitral stenosis, tissue Doppler velocities illustrated improvement of regional LA function after PMMC, in relation to decreased transmitral pressure gradient.
Atrial Function, Left↗
The non-circular shape of FloWatch-PAB prevents the need for pulmonary artery reconstruction after banding. Computational fluid dynamics and clinical correlations.
OBJECTIVE: To evaluate the differences between non-circular shape of FloWatch-PAB and conventional pulmonary artery (PA) banding. METHODS: Geometrical analysis. Conventional banding and FloWatch-PAB perimeters were plotted against cross-sections. Computational fluid dynamics (CFD) model. CFD compared non-circular FloWatch-PAB cross-sections with conventional banding regarding pressure gradients. Clinical data. Seven children, median age 2 months (7 days to 3 years), median weight 4.2 kg (3.2-9.8 kg), with complex congenital heart defects underwent PA banding with FloWatch-PAB implantation. RESULTS: Geometrical analysis. Conventional banding: progressive reduction of cross-sections was accompanied by progressive reduction of PA perimeters. FloWatch-PAB: with equal reduction of cross-sections the PA perimeter remained constant. CFD model. Non-circular and circular banding provided same trans-banding pressure gradients for same cross-sections at any given flow. Clinical data. Mean PA internal diameter at banding was 13.3+/-4.5 mm. After a mean interval of 5.9+/-3.7 months, all children underwent intra-cardiac repair and simple FloWatch-PAB removal without PA reconstruction. Mean PA internal diameter with FloWatch-PAB removal increased from 3.0+/-0.8 to 12.4+/-4.5 mm (normal mean internal diameter for the age=9.9+/-1.6). No residual pressure gradient was recorded in correspondence of the site of the previous FloWatch-PAB implantation in 6/7 patients, 10 mmHg peak and 5 mmHg mean gradient in 1/7. CONCLUSIONS: The non-circular shape of FloWatch-PAB can replace conventional circular banding with the following advantages: (a) the pressure gradient will remain essentially the same as for conventional circular banding for any given cross-section, but with significantly smaller reduction of PA perimeter; and (b) PA reconstruction at the time of de-banding for intra-cardiac repair can be avoided.
Blood Vessel Prosthesis↗
Prevalence and severity of paravalvular regurgitation in the Artificial Valve Endocarditis Reduction Trial (AVERT) echocardiography study.
OBJECTIVES: The purpose of this study was to determine the prevalence and severity of paravalvular regurgitation (PVR) in the Artificial Valve Endocarditis Reduction Trial (AVERT) cohort. BACKGROUND: The initial AVERT cohort consisted of 807 patients randomized to receive either a Silzone-coated prosthetic valve or a conventional prosthetic valve; early clinical reports showed higher rates of valve explant caused by PVR for Silzone-coated prosthetic valve. METHODS: Of the 678 eligible patients, 575 (85%) underwent postoperative transthoracic echocardiograms. The presence and severity of PVR were identified by color flow Doppler. Reviewers were blinded to the type of prosthetic valve and the demographic and clinical variables. RESULTS: Among those who underwent echocardiography (Silzone-coated prosthetic valve, n = 285 and conventional prosthetic valve, n = 290), 59% had prosthetic aortic valves, 32% prosthetic mitral valves, and 9% had both; demographic and clinical findings (i.e., prosthetic valve endocarditis, thromboembolism, bleeding, and all-cause death) were similar for the two groups. Echocardiographically determined PVR was present in 50 valves: Silzone-coated prosthetic valve, 29 of 285 (10%) and conventional prosthetic valve, 21 of 290 (7%, p = NS); the severity of PVR was similar in both groups. Kaplan-Meier analysis showed no significant differences in PVR at 24 months from valve implantation between the two groups (24-month event-free rate: 93% Silzone-coated prosthetic valve vs. 94% conventional prosthetic valve, p = NS). CONCLUSIONS: Excluding those patients who had initial prosthetic valve explant, the two-year echocardiographic follow-up of the AVERT cohort shows no statistically significant differences in the prevalence or severity of PVR in the Silzone-coated prosthetic valve compared with the conventional prosthetic valve. Further monitoring is warranted to determine whether these clinical outcomes remain similar on long-term follow-up.
Aged↗
Transthoracic echocardiographic assessment of periprosthetic mitral regurgitation using intravenous injection of sonicated albumin.
Mechanical prostheses induce artifacts that decrease the accuracy of conventional transthoracic echocardiographic imaging for the detection and quantitation of periprosthetic mitral regurgitation. In 15 patients undergoing transthoracic echocardiography, injection of sonicated albumin significantly enhanced the assessment of periprosthetic mitral regurgitation with an accuracy similar to that of transesophageal echocardiography.
Adult↗
Usefulness of transesophageal echocardiography in the assessment of aortic graft dehiscence.
The diagnosis and site of graft dehiscence determined by transesophageal echocardiography (TEE), transthoracic echocardiography (TTE), and aortography in 6 patients, and by computed tomography (CT) scan in 3 patients were compared with surgery. Sensitivity of TEE was 100%, aortography 83%, CT scan 67%, and TTE 33%; TEE accurately identified severe aortic regurgitation (3), graft narrowing (2), distal aortic dissection (1), and a fistulous communication between the aortic root and the right ventricle (1) when compared with surgery or aortography.
Adult↗
Intraoperative echocardiographic detection of regurgitant jets after valve replacement.
BACKGROUND: Paravalvular jets, documented by intraoperative transesophageal echocardiography, have prompted immediate valve explantation by others, yet the significance of these jets is unknown. METHODS: Twenty-seven patients had intraoperative transesophageal two-dimensional color Doppler echocardiography, performed to assess the number and area of regurgitant jets after valve replacement, before and after protamine. Patients were grouped by first time versus redo operation, valve position and type. RESULTS: Before protamine, 55 jets were identified (2.04+/-1.4 per patient) versus 29 jets after (1.07+/-1.2 per patient, p = 0.0002). Total jet area improved from 2.0+/-2.2 cm2 to 0.86+/-1.7 cm2 with protamine (p<0.0001). In all patients jet area decreased (average decrease, 70.7%+/-27.0%). First time and redo operations had similar improvements in jet number and area (both p>0.6). Furthermore, mitral and mechanical valves each had more jets and overall greater jet area when compared to aortic and tissue valves, respectively. CONCLUSIONS: Following valve replacement, multiple jets are detected by intraoperative transesophageal echocardiography. They are more common and larger in the mitral position and with mechanical valves. Improvement occurs with reversal of anticoagulation.
Adult↗
Variability of porcelain color reproduction by commercial laboratories.
STATEMENT OF PROBLEM: Many investigations in the field of metal ceramics have examined materials, manipulative variables, and the relationship of these factors to a restoration's color. However, the effect of the artistic component of restoration fabrication is not known. PURPOSE: The purpose of this study was to determine through instrumental colorimetry the variability in color reproduction for metal ceramic crowns fabricated by commercial dental laboratory technicians. MATERIALS AND METHODS: Fifty metal ceramic crowns were fabricated on standardized metal frameworks to the same shade specifications by 5 commercial dental laboratories (n=10). Laboratory prescriptions requested that the technician match the shade and translucency of a provided Vita Lumin A3.5 shade tab. Technicians used the porcelain and technique of their own selection to match the tab. Color differences were determined by use of a colorimeter between crowns and the prescribed shade tab at middle and incisal sites. Analysis of variance was used to determine whether differences in color reproduction existed among laboratories. Where statistically significant interactions existed, the Tukey honestly significant difference test was used to determine significant differences between laboratories according to sites (alpha=.05). RESULTS: Color reproduction was significantly different (P <.0001) among laboratories for both sites. Mean color difference from shade tabs ranged from 3.5 to 11.1 DeltaE units. All laboratories were better at matching shades in the incisal third of the crown. CONCLUSION: Within the limitations of this study, the ability to reproduce the color of the target shade tab differed among laboratories. Most crowns fabricated by the laboratories in this study, when compared to the prescribed shade tab, were above the clinical threshold for an acceptable shade match under intraoral conditions (DeltaE 3.7).
Analysis of Variance↗
Atrioventricular valve repair using externally adjustable flexible rings.
Initial results obtained with a new flexible ring, adjustable from outside of the heart after interruption of extracorporeal circulation, are presented. Twenty-five rings have been inserted in 20 patients, 14 in the mitral position and 11 in the tricuspid position. In 8 of the 14 patients receiving mitral annuloplasty, other standard mitral valve repair techniques were used. Adjustment, assisted by intraoperative transesophageal color Doppler echocardiography, was done for 10 (71%) of the mitral rings and for 8 (73%) of the tricuspid rings. Residual mitral regurgitation disappeared or became minimal in 9 (90%) patients, and a mild regurgitation remained in 1. In all patients who received tricuspid rings regurgitation was abolished after the adjustment. There was no hospital or late mortality. After a maximum follow-up of 6 months results are comparable in the tricuspid and mitral positions and echocardiographic evaluation revealed stable competent valves in all patients but one, who underwent reoperation because of failure of a mitral valve chordae shortening procedure. The use of externally adjustable rings for the mitral and tricuspid valves is a safe alternative for atrioventricular valve annuloplasty and has the additional advantage of reducing postrepair regurgitation.
Adolescent↗
Early results with partial left ventriculectomy.
OBJECTIVE: We sought to determine the role of partial left ventriculectomy in patients with dilated cardiomyopathy. METHODS: Since May 1996 we have performed partial left ventriculectomy in 53 patients, primarily (94%) in heart transplant candidates. The mean age of the patients was 53 years (range 17 to 72 years); 60% were in class IV and 40% in class III. Preoperatively, 51 patients were thought to have idiopathic dilated cardiomyopathy, one familial cardiomyopathy, and one valvular cardiomyopathy. As our experience accrued we increased the extent of left ventriculectomy and more complex mitral valve repairs. For two patients mitral valve replacement was performed. For 51 patients the anterior and posterior mitral valve leaflets were approximated (Alfieri repair); 47 patients also had ring posterior annuloplasty. In 27 patients (51%) one or both papillary muscles were divided, additional left ventricular wall was resected, and the papillary muscle heads were reimplanted. RESULTS: Echocardiography showed a significant decrease in left ventricular dimensions after resection (8.3 cm to 5.8 cm), reduction in mitral regurgitation (2.8+ to 0), and increase in forward ejection fraction (15.7% to 32.7%). Cardiac index did not increase significantly (2.2 to 2.4 L/min per square meter). Eight patients (15%) required a perioperative left ventricular assist device; one died and was the only perioperative mortality (1.9%). At 11 months, actuarial survival was 87% and freedom from relisting for transplantation was 72%. CONCLUSIONS: Improved selection criteria are necessary to avoid early failures, and much more follow-up and analyses of data are mandatory. However, the operation may become a biologic bridge, or even alternative, to transplantation.
Cardiomyopathy, Dilated↗
[The measurement of jet width at its origin in assessing mitral prosthetic regurgitation. The effect of the spatial disposition of the jet].
INTRODUCTION AND OBJECTIVES: The study was performed to test the influence of the jet spatial disposition on the correlation degree between the measurement of the jet width at its origin and the severity of mitral prosthetic regurgitation by transesophageal Doppler color flow imaging. MATERIAL AND METHODS: In 165 patients with mitral valve prosthesis which were submitted for transesophageal echocardiography examination due to suspected prosthetic dysfunction, we studied 126 with pathological mitral regurgitation. On these patients, studies of jet spatial disposition, maximum width in its origin and severity quantification by means of maximum regurgitation area were performed. RESULTS: For the free jet group of patients (90), jet width at its origin correlated with maximal regurgitation area (r = 0.75); whereas for the wall jet group (36), the correlation degree was 0.59. We observed a relationship (p < 0.05) between severe mitral regurgitation assessed by maximal regurgitant jet size and jet width > or = 5 mm in both groups: the sensitivity and specificity of 72.7% and 95% respectively for free jets, and 70.7% and 64.4% for wall jets. CONCLUSIONS: The correlation between the area measurement and the width in its origin is better for free jets than for wall jets. A statistically significant relationship between the presence of severe mitral regurgitation and width in its origin > or = 5 mm could be observed, independently of the jet spatial disposition.
Adult↗
Recognition of veneer restorations by dentists and beautician students.
Three types of veneer restorations (VRs) were evaluated for recognition by two groups of observers to study the aesthetic result. The different types of VRs were: porcelain, direct resin composite and indirect resin composite. One month after insertion of the VRs, colour transparencies were made of smiling patients randomly selected from a group of 112 patients participating in a clinical trial. The slides were evaluated by five dentists who were not familiar with the patients and by 25 beautician students (BS). Dentists were asked to locate the VRs which were present in the patients and to specify the type of VR. BS were only asked to locate the VRs. To trace a possible relationship between the aesthetic result of the treatment and a number of variables, ANOVA was applied to evaluate the variables: 'discolouration of the teeth' before treatment, 'type of VR' and 'number of VRs'. Agreements in judgement were expressed in Cohen-Kappa coefficients. The results showed that the dentists could locate the VRs quite well (Kappa coefficient 0.64 +/- 0.28) but for BS this was lower (Kappa coefficient 0.43 +/- 0.27). The more VRs were made in one patient, the more difficult it was to locate them correctly. The other variables had no significant effect on the recognition of the VRs. It was not possible for the dentist observers to differentiate between the types of VRs.
Adult↗
Porcine stentless bioprostheses: prevention of aortic wall calcification by dye-mediated photo-oxidation.
PURPOSE: Aortic wall calcification is problematic in stentless porcine valves. We evaluated the possible anticalcification effect of photo-oxidation on the aortic wall portion of porcine stentless bioprostheses. A comparison with glutaraldehyde-fixed tissue was made. METHODS: Six Photofix and six Freestyle valves were implanted in juvenile sheep in pulmonary position. Valves were explanted after 3 or 6 months and examined macroscopically, by x-ray, light, and transmission electron microscopy. Calcium content was determined by atomic absorption spectrometry. RESULTS: The aortic wall portion of all Photofix valves remained free from calcification, while the wall portion of glutaraldehyde-fixed valves calcified strongly, both after 3 and 6 months. Calcium content of the aortic wall portion was: 0.71 +/- 1.27 in the Photofix valves versus 10.78 +/- 77.22 in the Freestyle valves (P < 0.05). CONCLUSION: Photo-oxidation of a porcine stentless valve prevents calcification not only in the cusps but also in the aortic wall portion.
Animals↗