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M Concha

Publications and source records attributed to M Concha.

At least 91 records · Page 5Linked to original sources
PubMed1988

Conservative operation for mitral stenosis. Independent determinants of late results.

A retrospective study was designed to define the independent determinants of late results in 282 consecutive patients operated on for mitral stenosis between 1978 and 1985. A total of 25 variables were investigated by multivariate discriminant analysis for their possible influence on symptomatic outcome, subsequent reoperation, postoperative thromboembolism, and death. All the patients underwent a conservative mitral valve operation. In addition, 25 patients required concomitant tricuspid annuloplasty. The surgical mortality rate was 1.4% and the late mortality, reoperation, and thromboembolism rates were, respectively, 0.14%, 0.80%, and 0.95%/pt-yr. Actuarial probability of complication-free survival at 8 years was 83% +/- 3.7%. Left atrial size on the M-mode echocardiograms, tricuspid annuloplasty, mitral annuloplasty, presence of left atrial thrombus, male gender, and separation of subvalvular apparatus portended a significantly higher likelihood of poor postoperative symptomatic status (p less than 0.0005). Preoperative mild mitral regurgitation, E to F slope on the M-mode echocardiogram, and tricuspid annuloplasty had significant influence on the need for late reoperation (p less than 0.05). Postoperative atrial fibrillation, mitral valve amplitude on the M-mode echocardiogram, preoperative embolism, and residual mitral incompetence had an independent predictive power for postoperative thromboembolism (p less than 0.05). Finally, preoperative atrial fibrillation, preoperative cardiothoracic ratio, postoperative left atrial size, and postoperative atrial fibrillation all influenced the probability of long-term complications. These results suggest that earlier operation should be considered in patients with mitral stenosis, to increase the complication-free survival rate.

Actuarial Analysis↗
PubMed1988

Mitral and aortic valve decalcification by ultrasonic energy. Experimental report.

In this investigation we used ultrasonic energy to decalcify 10 mitral and six aortic valves after they had been surgically removed. The calcium was disintegrated in all cases and normal valvular tissue was preserved. The fragments of disintegrated calcium were collected in a suction bottle, which prevented peripheral embolism. The ultrasonic urologic probe is an unwieldy instrument for cardiac surgery, and we suggest the manufacture of a new probe for clinical use in our specialty.

Aortic Valve↗
PubMed1987

Assessment of Björk-Shiley and porcine mitral valve dysfunction by m-mode echocardiographic left ventricular dimension.

In this study of 46 patients with mitral valve prostheses, we report on the accuracy of the left ventricular maximum filling velocity (LVMFV) index as a diagnostic tool for valve dysfunction. Echocardiographic left ventricular internal dimensions were measured every 0.05 seconds, and every measure was transferred to an axis system. The tangent to this curve was traced at the point of maximum rate of increase of dimension, and the slope in mm/sec represents the LVMFV index. Six patients, each with an obstructed mitral valve prosthesis, had a reduced LVMFV index (p < 0.001). On the other hand, eight patients with a paravalvular leak showed a LVMFV index significantly higher (p < 0.05) than patients with a normally functioning mitral valve prosthesis. The results of this study suggest that analysis of the LVMFV index can be a useful and reliable substitute for other noninvasive diagnostic techniques in evaluating certain patients with suspected prosthetic mitral valve malfunction.

Journal Article↗
PubMed1987

Conservative operation for mitral stenosis with densely fibrosed or partially calcified valves. An eight-year evaluation.

Of 284 patients undergoing open mitral commissurotomy for mitral stenosis from January 1978 to December 1985, 81 patients had a densely scarred or partly calcified valve. In this study, we evaluated the postoperative results in these 81 patients. There were no operative or late deaths. Seventy-seven patients (95%) are in Functional Class I or II. Three patients required reoperation 3, 30, and 50 months after the initial procedure because of moderate or severe residual mitral regurgitation. After valvotomy there were four episodes of embolism. The actuarial rate of freedom from any complication (mortality, reoperation, congestive heart failure, and thromboembolic events) was 89.3% +/- 3.9% (mean +/- standard error of the mean) 8 years after operation. We conclude that for a follow-up period of 8 years, the stenotic mitral valve with anatomical deformities can be salvaged with satisfactory results. Therefore, we believe that this approach, at present, is a better alternative than prosthetic replacement with any type of valve presently available.

Adult↗
PubMed1986

Percutaneous transluminal balloon dilatation for discrete subaortic stenosis.

Seven patients, mean age 8 +/- 3.6 years, with clinical and hemodynamic diagnoses of discrete subaortic stenosis were treated by percutaneous transluminal balloon dilatation (PTBD) of the membrane during cardiac catheterization. One patient had an associated aortic coarctation that was first dilated. After PTBD left ventricular (LV) systolic pressure decreased significantly, from 181 +/- 25 to 139 +/- 11 mm Hg (p less than 0.005); peak gradient diminished from 65 +/- 18 to 12 +/- 9 mm Hg (p less than 0.001). Mild aortic regurgitation was present in 6 patients during basal conditions. After PTBD, the same degree of regurgitation was observed in all but 1 patient, in whom it disappeared. There were no major complications. Clinical observations after PTBD were consistent with hemodynamic findings. Precordial thrill always disappeared and the peak murmur became earlier in systole. In 2 patients the discrete subaortic stenosis was clearly visualized at 2-dimensional echocardiography as a fixed subvalvular structure throughout the cardiac cycle. After dilatation this was only identifiable at its implantation base; during contraction there was no fixed structure at the LV outflow tract. Four patients were hemodynamically reevaluated 6.7 +/- 1.7 months later and were found to have LV pressure relief and a degree of aortic regurgitation similar to those observed immediately after PTBD.

Angioplasty, Balloon↗
PubMed1986

Cytochemistry and ultrastructure of normal and neoplastic cells exfoliated from the human uterine cervix.

Cells exfoliated from the uterine exocervix from normal women at different stages of the reproductive period and from patients with invasive carcinoma were studied. Cell pellets were fixed in aldehydes and two different concentrations of OsO4, and embedded in methacrylate or Epon. Semithick sections were used for general light microscopic study and for the visualization of glycogen. Ultrathin sections were used for conventional electron microscopy, high resolution analysis of the plasma membrane, and the demonstration of glycogen and cell surface glycoconjugates by the Thiery method. Semithick sections stained with the Thiery method and viewed under the electron microscope were used for the study of surface projections. Based on the size, shape, nuclear characteristics, amount and distribution of glycogen, type of surface protrusions, density and distribution of surface glycoconjugates, and plasma membrane fine structure, the cells exfoliated from all normal uterine cervices were grouped into five cell types. It is suggested that these types correspond to cells located in the different layers of the exocervical epithelium and, consequently, represent different degrees of normal differentiation. The plasma membrane of carcinoma cells shared most of the characteristic of that of the least differentiated normal cells, indicating an early deviation of the differentiation process in carcinoma cells.

Carcinoma, Squamous Cell↗
PubMed1985

Intraoperative contrast two-dimensional echocardiography. Evaluation of the presence and severity of aortic and mitral regurgitation during cardiac operations.

We have used contrast two-dimensional echocardiography in the intraoperative evaluation of aortic and mitral regurgitation in 35 patients undergoing cardiac operations. All of them underwent previous cardiac catheterization in order to document the presence and severity of regurgitation. With the pericardium open, a catheter was introduced into the left ventricle (to document mitral regurgitation) or into the ascending aorta (to document aortic regurgitation). The two-dimensional echocardiographic probe was placed on the anterior surface of the right ventricle to obtain a basal image, equivalent to a conventional parasternal longitudinal view. Dextrose in water (5 ml) was rapidly hand-injected through the catheter, while echocardiograms were recorded on videotape. The observation of contrast medium (microbubbles) flowing in the retrograde direction through the incompetent valve was carefully evaluated with the same scoring system used in the hemodynamic laboratory. In 34 cases there was agreement between angiographic and echocardiographic evaluation of the presence and severity of mitral and aortic regurgitation. Only one case was evaluated as mild aortic regurgitation by angiography and moderate aortic regurgitation by echocardiography. There were no false positives or false negatives in the study. In view of the high degree of correlation between contrast two-dimensional echocardiography and hemodynamic data, we suggest that our method is an important tool for the cardiac surgeon. In addition, the present approach overcame the disadvantages of the conventional intraoperative methods, most of which are performed in a nonbeating or fibrillating heart.

Adult↗
PubMed1984

Contrast bidimensional echocardiography in the morphologic and functional postoperative evaluation of the Senning technique for complete transposition of the great vessels.

Contrast bidimensional echocardiographic (2DE) studies were performed in eight patients with d-transposition of the great vessels in the postoperative period of the Senning technique. Contrast was injected into a peripheral vein of all patients, and into the arterial atrium in five in the postoperative period. The 2DE projections used were the four-chamber apical view and four-chamber subcostal view. In all patients it was possible to see and identify the new atrial cavities which greatly resembled the actual anatomy. Early postoperative alternating injections of contrast in both new atria not only achieved the main purpose of delineating the real anatomy, but also permitted more definitive identification of residual shunts.

Child, Preschool↗
PubMed1984

Early disc dislodgement of a mitral Björk-Shiley prosthesis.

Because of its excellent durability, low-flow gradient and low incidence of valve-related complications, the Björk-Shiley prosthesis is one of the most widely used valve prostheses in the world. Component failures are rare with this prosthesis. The following report, however, described a case of early disc dislodgement of a mitral Björk-Shiley prosthetic valve.

Journal Article↗
PubMed1983

Poly(ADP-ribose) synthetase associated to cytoplasmic structures of meiotic cells.

An active poly(ADP-ribose) synthetase has been found to be associated to mitochondria of frog oocytes and of testis from various species. The enzyme was also found in association with the microsomal-ribosomes fraction of the testis. Both enzymes are strongly inhibited by nicotinamide, thymidine, and theophylline, and they synthesize oligomers of ADP-ribose of an average chain length of 2-6 residues. The apparent km for NAD+ of the mitochondrial enzyme is 22 micro M which contrasts with the corresponding value of the chromatin-bound enzyme, 210 micro M NAD+. Treatment of the isolated mitochondria with Triton X-100 revealed that the enzyme is associated to a polydisperse structure. The higher specific activity of the enzyme associated to mitochondria was found in testis of 20 to 30 days old rats. This development study suggest that the maximal activity of the enzyme is associated to mitochondria belonging to primary spermatocytes. Poly(ADP-ribose) synthetase was also found in association of the microsome-ribosome fraction of rat, mouse, carp, and bull testis. This activity is 20 to 30 times higher than in the same fraction of the liver. Contrary to the chromatin-bound enzyme, the microsome-ribosome enzyme activity is stimulated 3 to 4 times by DNA, but it is slightly inhibited by histone H1. The enzyme seems to be associated to ribonucleoproteins of a very polydisperse nature. The possible relationship of poly(ADP-ribose) synthetase with the intermitochondrial cement and with the chromatoid body will be discussed. These are very unique structures only present in germinal cells.

Animals↗