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Biomedical subjects

A Ameur

Publications and source records attributed to A Ameur.

11 recordsLinked to original sources
PubMed1985

Valvar prosthetic dysfunction. Localisation and evaluation of the dysfunction using the Doppler technique.

Thirty patients with 33 mitral or aortic prostheses or both were examined using the pulsed Doppler technique combined with cross sectional echocardiography to study the applicability of the Doppler technique in the diagnosis and evaluation of the severity of prosthetic dysfunction and to assess the ability of the mapping procedure to estimate the site and the size of the prosthetic defect. The dysfunction was valvar regurgitation in 29 instances and stenoses in eight, all of which were confirmed by invasive procedures. The severity of the dysfunction was graded on a three point scale. A control group of 73 subjects with 88 normal prostheses also underwent pulsed Doppler and cross sectional echocardiography. The pulsed Doppler study followed the usual procedure for a valvar disease including two and three dimensional mapping for regurgitation. Eight patients also underwent a continuous wave Doppler examination. The diagnostic reliability of the pulsed Doppler technique was greater than or equal to 90%. The severity of the dysfunction was accurately assessed in 86% of cases. In the case of aortic regurgitation, mapping of the jets was performed as easily for prostheses as for native regurgitant valves. In the case of mitral regurgitation, the mapping patterns depended on the cause of the dysfunction. With valvar tears, a jet was detected at the centre of the annulus, and with paravalvar leaks eccentric atrial jets were seen opposite the site of the leak. The pulsed Doppler and the surgical findings correlated well for both the site of the dysfunction (16/20 (80%) patients) and the size of the leak (13/16 (81%) patients). Thus, despite some limitations, pulsed Doppler and particularly the mapping procedure provide sufficient information to give an accurate non-invasive assessment of prosthetic valve dysfunction.

Aortic Valve↗
PubMed1984

Calculation of pulsed Doppler left ventricular outflow tract regurgitant index for grading the severity of aortic regurgitation.

Measurement of the spatial extent of the regurgitant jet was performed in the left ventricular outflow tract (LVOT) with a 3 MHz two-dimensional echo-pulsed Doppler device, in order to assess the severity of aortic regurgitation on a quantitative basis. The procedure included: detection of diastolic disturbances in the LVOT and mapping of these disturbances in the LVOT. Length (L) and height (H) were measured with calculation of the product (L X H) in the long-axis view and width (W) in the short-axis view with calculation of the LVOT regurgitant index (LVOTRI) as follows: ([L X H] X W). Twelve normal subjects and a group of 83 patients, including 40 patients with aortic regurgitation proved by aortography, were investigated with this procedure. Diagnostic reliability ranged between 90% for specificity and 95% for sensitivity. Correlations between the grading provided by the LVOTRI and those provided by aortography on a three-grade scale showed a correlation coefficient between 0.67 (linear model, p less than 0.01) and 0.80 (exponential model), because of the high values of the index in cases of severe regurgitation. Reliability of the LVOT investigation in aortic regurgitation requires the use of information from two combined scan planes and quantitative rather than qualitative data. Main limitations of the procedure are due to the presence of associated mitral lesions.

Adolescent↗
PubMed1984

Pulsed Doppler echocardiographic indices for assessing mitral regurgitation.

Pulsed Doppler indices were devised in order to grade the severity of mitral regurgitation on a quantitative basis. Indices were obtained by mapping the regurgitant jet by recording abnormal systolic Doppler signals detected on a "yes/no" basis using a 3 MHz pulsed Doppler velocimeter associated with a cross sectional real time ultrasonic scanner. Combined information from two echographic planes was used to take into account the geometrical three dimensional configuration of the jet. The following dimensions of the jet were measured: (a) the length and the height in the long axis view of the left atrium (long axis regurgitant index (LARI), 0.5 X length X height); (b) the width at the annulus in the short axis view (short axis regurgitant index (SARI); (c) the total regurgitant index (TRI) calculated as the product of LARI multiplied by SARI. Sixteen normal subjects and 94 patients including 46 cases of mitral regurgitation confirmed by angiography (32 of whom proceeded to surgery) were investigated. The diagnostic sensitivity was 91% and the specificity 94%. The jet was detected in 76% of cases. Indices were correlated with independently performed angiographic grading on a three point scale. The best linear correlation was obtained for the TRI; mean values were significantly increased for each grade of severity. Correlations with invasive procedures showed an 87% success rate for the Doppler prediction of the involved regurgitant leaflet(s) and of the anatomical site of the lesion at the annulus. In addition, an abnormal diastolic signal was found in five of the eight patients with ruptured chordae and also a decreased percentage of systolic shortening of the annulus diameter in patients with mitral regurgitation compared with those without.

Adult↗
PubMed1984

[Aortic valve replacement by bioprosthesis with enlargement of the aortic ring].

Small diameter aortic valve bioprostheses are associated with resting ventriculo-aortic pressure gradients of 10 to 35 mmHg. In order to avoid this factor favouring degradation of left ventricular function and early deterioration of the bioprosthesis, we enlarged the aortic ring when the diameter was less than 23 mm in patients considered unsuitable for long-term anticoagulation. The surgical technique involved incising the annulus from the postero-lateral commissure to the anterior mitral leaflet and implanting a Dacron patch lined with pericardium. Nine patients aged from 10 to 70 years (average 22 years) underwent aortic valve replacement with a Carpentier-Edwards bioprosthesis associated with enlargement of the aortic ring, between June 1979 and December 1981. The mean follow-up period is now 18 months (range 9 to 39 months). One patient has been lost to follow-up. Before surgery, 6 patients were in Stage III and 3 patients in Stage IV of the NYHA classification. There were 4 patients with pure aortic regurgitation with valve prolapse, 1 patient with aortic regurgitation due to endocarditis, and 4 patients with mixed aortic valve disease. The underlying disease was rheumatic in 6 cases, congenital in 2 cases and infective endocarditis in 1 case. The mean diameter of the aortic ring before enlargement was 19 mm. After the procedure, it increased to 23,8 mm, so enabling the implantation of no 23 and no 25 bioprostheses. Three patients had associated mitral regurgitation, 3 patients had mixed mitral valve disease, 1 patient had a membranous VSD with infundibular stenosis, and 1 patient had subvalvular aortic stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

New indexes for assessing aortic regurgitation with two-dimensional Doppler echocardiographic measurement of the regurgitant aortic valvular area.

Direct examination of the aortic orifice at the level of the aortic valves (aortic valvular orifice area, AVOA) in the short-axis plane was performed with a 3 MHz two-dimensional pulsed Doppler echocardiographic apparatus. The AVOA was mapped with the Doppler gate to detect or rule out the presence of a regurgitant aortic valvular area (RAVA) established by recording of abnormal diastolic Doppler signals on a "yes or no" basis. A group of 12 normal subjects and 83 patients, including 40 patients with aortic regurgitation proven by aortography, were investigated with this procedure. In the 38 patients with aortic regurgitation diagnosed by Doppler echocardiography (diagnostic sensitivity 95%, specificity 100%), planimetric measurements of the RAVA and AVOA were performed with calculation of two indexes: the RAVA/square meter of body surface area and the RAVA/AVOA ratio. These indexes correlated well with independently performed angiographic grading on a three-point scale (r = .87 for the RAVA, .88 for the RAVA/AVOA; p less than .001), with highest significance of differences in mean values among each grade of severity found for the RAVA/AVOA (p less than .001). In addition, Doppler echocardiography identified the anatomic valvular site of the lesion, and we confirmed the site during surgery.

Adolescent↗
PubMed1983

Mitral reconstructive operations. A series of 130 consecutive cases.

Between January, 1975, and January, 1982, 130 patients underwent mitral valvuloplasty for pure or predominant mitral insufficiency. Mean age at operation was 30 +/- 17 years. Twenty-five patients were under 15 years of age. Mitral insufficiency was mainly (112/130) due to rheumatic disease. Fifty-nine patients (45.4%) had another diseased valve which necessitated a surgical correction (tricuspid in 36 and aortic in 23). Surgical technique for mitral valvuloplasty varied according to the lesions. Three patients died in the first month after operation (2.3%). Five patients are lost to follow-up. The mean follow-up period for the 122 remaining patients is 38 +/- 27 months. Seven patients required reoperation and three of them died. An additional patient died without reoperation. Therefore, the late mortality was 3.1% (4/122). Almost all (116/118) of the remaining patients are in Class I (105) or II (11) of the New York Heart Association. Mean cardiothoracic ratio decreased from 60.6% +/- 7.7% preoperatively to 53.7% +/- 6.2% postoperatively (p less than 0.001). Thromboembolic episodes were noted in four patients, all of them in atrial fibrillation. Actuarial curves including hospital mortality showed a 92.0% survival rate at 7 years for the overall series (1.0% +/- 0.5%/patient-year), 93.7% +/- 4.9% at 7 years for isolated mitral reconstruction and 89.9% +/- 5.6% for mitral-tricuspid valvuloplasty at 5 years. The embolism-free rate at 7 years was 91.2%, with a rate of thromboembolic episodes of 1.0 +/- 0.5%/patient-year. Eighty-eight percent were free of reoperation at 7 years, with a rate of reoperation of 1.7 +/- 0.7%/patient-year. This system of mitral repair can provide stable functional results, low surgical and late mortality, and an acceptable rate of reoperation.

Adolescent↗
PubMed1980

[Histological and ultrastructural study of the left ventricular myocardium in mitral stenosis. Correlations with angiocardiographic indices of left ventricular function. Eleven cases].

Left ventricular myocardial biopsy was carried out at operation in 11 patients with pure, isolated mitral stenosis after preoperative angiocardiographical assessment of left ventricular function. The biopsy specimens were examined by light and electron microscopy. The diameter of the myocytes was normal (20 +/- 1.6 mu). The changes observed were probably of a degenerative type with anarchy and irregularities in the sarcomeres, modification of the Z bands, as seen in Nemaline myopathies, and changes in the intercalatory discs. Moderate interstitial fibrosis with scanty histiocytes was also observed. A quantitative assessment by two dimensional planimetry showed a significant increase in the interstitial space (37 +/- 5.5%) compared to a control group without fibrosis (22 +/- 1.1%). The angiocardiographical indices of left ventricular function were all decreased. The amplitude of circumferential fibre shortening was reduced: 25 +/- 6% the ejection fraction by 52 +/- 9% and the average speed of circumferential fibre shortening by 1.0 +/- 0.3 circ/s. Only four patients had normal left ventricular function (ejection fraction > 55%). However, it was not possible to establish a significant correlation between the degree of fibrosis and the reduction in left ventricular function. Left ventricular fibrosis may be one of the factors responsible for the reduction of myocardial function, but it does not in itself explain all the changes in left ventricular function observed in mitral stenosis.

Adolescent↗