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Biomedical subjects

C M Duran

Publications and source records attributed to C M Duran.

At least 55 records · Page 3Linked to original sources
PubMed1995

Aortic valve replacement with autologous pericardium: surgical technique.

The surgical technique of aortic valve replacement with freehand glutaraldehyde-treated autologous pericardium is described. Forty-nine patients underwent this procedure without hospital mortality and no thromboembolic episodes without anticoagulation. Three patients underwent reoperation: for infective endocarditis in two; and tear of one commissure 8 months after surgery in another. This technique because of its excellent hemodynamics and low thrombogenicity might be a valid alternative particularly in patients with a small aortic annulus.

Adolescent↗
PubMed1995

Comparison of fresh and glutaraldehyde-treated autologous stented pericardium as pulmonary valve replacement.

The use of fresh autologous pericardium in valve surgery has shown poor results in the past mainly due to thickening and retraction. Recently, it has been suggested that a short treatment with glutaraldehyde might radically change its behavior. In an attempt to determine whether this disparity in results is due to the glutaraldehyde treatment or to a better present-day surgical technique, fresh and glutaraldehyde-treated autologous pericardium was mounted in a frame and implanted in the pulmonary position of adult sheep. Six survivors obtained in each group were sacrificed between 2 and 8 months in the "fresh" group and between 2 and 6 months in the "glutaraldehyde-treated" group. Macroscopically, the fresh pericardium became thickened and retracted in all specimens, eventually resulting in severe regurgitation, while the glutaraldehyde-treated, although slightly thickened, retained its pliability without significant retraction. Microscopically, viability of the central core of the collagen was more often preserved in the fresh pericardium. Endothelialization was irregular. In conclusion, short glutaraldehyde treatment seems to improve the results of autologous pericardium mounted on a valve stent. Its effect on calcification remains to be ascertained.

Animals↗
PubMed1995

In situ mitral valve stabilization with glutaraldehyde.

Mitral valve repair in the young rheumatic patient carries a high reoperation rate due to progression of the disease. In an attempt to halt or at least slow down this process, the possibility of fixing in situ the valve tissues with glutaraldehyde was explored. Six weanling sheep underwent tanning of their anterior mitral leaflet for two minutes with 0.5% buffered glutaraldehyde. The non-treated posterior mitral leaflet served as control. The animals were sacrificed at varying intervals between 2.5 and 6 months. At sacrifice, Doppler echocardiography and hemodynamic studies were done. The leaflets were subjected to histopathologic examination and calcium and glutaraldehyde contents were estimated. Glutaraldehyde treatment of the anterior leaflet caused thickening of the cusp and chordae associated with partial devitalization of its core tissue, partial loss of endothelium and intense fibrocellular reaction with abundant elastic fibers without altering its functional integrity. It did not induce calcification. There were no detectable levels of glutaraldehyde at explantation. The posterior mitral leaflets were normal. Although the absence of calcification and partial viability of the tissue are encouraging, it does not necessarily follow that this treatment would arrest progression of the underlying disease. This process may have clinical application in the future, but it is not yet recommended.

Animals↗
PubMed1995

A revised terminology for recording surgical findings of the mitral valve.

The existing terminology for the various structures of the mitral valve are diverse and numerous. With the resurgence of interest in reparative procedures for mitral valve disease, it becomes imperative to have a unified terminology which would convey precise connotations in recording the pathology as well as the corrective procedures applied. In an effort to suggest a commonly acceptable nomenclature, we reviewed the available terminology and propose a simple system which will fulfil the needs of recording the intraoperative observations of the pathology of each valve and the manouveres carried out to correct them by the surgeon. This involves designating all structures anterior to the intercommissural line as "anterior" or "A" and those posterior as "posterior" or "P". The structures, as observed by the surgeon through a standard left atriotomy, to the left of the line dropped perpendicular to the middle of the aortic curtain will be designated by the numeral "1" and those to the right "2". The chords will be termed in groups based on their point of insertion, irrespective of whether they are inserted to the free edge or the ventricular surface of the leaflet. The anterior leaflet chords will further be subdivided based on their relation to the stay chords. We hope that this system of naming the structures would provide a unified method of reporting intraoperative findings of mitral valve disease.

Heart Valve Diseases↗
PubMed1994

Performance of 96 CarboMedics valve replacements in 75 patients less than twenty-one years of age.

Valve replacement still represents a problem in the very young patient. Between July 1988 and November 1993, 96 CarboMedics mechanical valves were implanted in 75 patients with a mean age of 11.76 years (range, 5 months to 20 years). The mean preoperative New York Heart Association functional class was 3.2, and 89.3% of the patients were in sinus rhythm. The cause was rheumatic in 60%, congenital in 24%, and infective in 12%. Mitral valve replacement was undertaken in 43 patients, aortic in 11, and mitroaortic in 21. Among the 18 patients with congenital defects, 13 required simultaneous repair of their complex lesions. The hospital mortality was 12% (9 patients). Cause and age were significant factors responsible for mortality. The mortality was 27.8% for patients with congenital disease and 6.7% for those with rheumatic defects (p = 0.0365); it was 40% for patients younger than 2 years, 14.3% for those between 3 and 10 years old, and 5.9% for those older than 10 years (p = 0.0108). The maximum follow-up was 54 months (mean, 18 months). There were 10 late deaths (15.15%). No embolic events occurred. All patients were on anticoagulation therapy except 2 who were on antiaggregant therapy. One of them underwent successful reoperation for treatment of mitral prosthetic thrombosis. Three reoperations were performed: one for thrombosis, one for perivalvular leak, and one for endocarditis. The total actuarial survival was 68.19% +/- 7.02%. Freedom from embolism was 100%; from thrombosis, 96.72% +/- 3.22%; from severe hemorrhage, 94.94% +/- 3.67%, and from reoperation, 83.07% +/- 9.51%.

Actuarial Analysis↗
PubMed1994

Aortic valve reconstruction in the young.

Aortic valve replacement in the young patient, and particularly in women of child-bearing age, still represents a problem. Between July 1988 and August 1993, 644 aortic valve patients (mean age 32.5 years) were operated in our institution. Aortic valve reconstruction was performed in 274 (42.5%). A variety of repair techniques (valvuloplasty) was used in 202 patients (mean age 21.5 years). Concomitant mitral surgery was performed in 103 (51%). In 72 patients (mean age 27.7 years), a cusp extension was undertaken with glutaraldehyde treated bovine (27 pts) or autologous (45 pts) pericardium. In the "plasty" group, there were 8 (4%) hospital deaths and 8 (4.1%) late deaths with an actuarial survival of 86.05% +/- 3.97%. No thromboembolic events were detected in patients with isolated aortic surgery. There were 32 reoperations without mortality, 22 due to progressive rheumatic disruption of the mitral repair. There was severe aortic dysfunction in 17 (8.76%) cases. There was no hospital mortality among the 72 patients with cusp extensions. There were two (2.8%) late deaths and no thromboembolic events. No patient was anticoagulated. Four patients required reoperation on the aortic valve without mortality. The last echocardiographic follow-up showed stability of the reconstruction. These techniques offer a valid alternative to valve replacement in this difficult category of patients.

Actuarial Analysis↗
PubMed1994

Tricuspid valve surgery revisited.

Contrary to general opinion, the tricuspid valve remains a challenge in terms of its precise diagnosis, indications, and appropriate surgical treatment. This is due to: (1) its relatively low incidence, (2) its functions in a low pressure system, (3) its close relation to right ventricular function, and (4) it following the dictates of the left-side lesions. In an attempt to elucidate its present status, we reviewed our experience under several categories: (I) Incidence: Among the 1298 valvular patients operated in a period of 5 years (July 1988 to August 1993), 306 (23.6%) native tricuspid valves required surgery. Among the 899 patients with rheumatic etiology, tricuspid involvement was present in 249 (27.7%). (II) Pathology: Excluding other pathologies, organic rheumatic disease was present in 126 (50.6%) and functional regurgitation in 123 (49.4%). However, 45.3% of the organic tricuspids had a dilated annulus, suggesting the existence of organofunctional lesions. (III) Diagnosis: Although two-dimensional echo-Doppler is a reliable diagnostic method, only 41.7% of the organic lesions were diagnosed preoperatively and the remaining at surgery. (IV) Influence of left-side lesions: In a previous study we showed that the postoperative functional status and cardiac output were primarily related to the results of surgery on the mitral valve, irrespective of whether the tricuspid valve had been correctly or incorrectly repaired or even ignored. (V) Surgical techniques: Because of these reasons, evaluation of the individual superiority is difficult, but all annuloplasties result in a degree of residual stenosis (30% to 70% of patients) that is more pronounced in those with organic lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Valve repair in rheumatic mitral disease: an unsolved problem.

UNLABELLED: Etiology plays an important role in the results of mitral valve repair. Although it is known that rheumatic disease is a negative factor, the possible influence of age has not been determined. In an attempt to study this factor, all consecutive Saudi patients operated for rheumatic mitral disease between July 1988 and December 1992 were reviewed. There were 537 patients (mean age 31.91 years). Replacement was performed in 231 patients and repair in 306. Follow-up was 98% complete with a maximum of 52 months (mean 20 months). The patients were divided by age into three groups: group I between 0 and 20 years (n = 145), group II between 21 and 40 years (n = 247), and group III older than 41 years (n = 145). The results showed repair rates of 76.6% (group I), 59.1% (group II), and 33.8% (group III). Actuarial survivals for repair were 95.87% (group I), 94.82% (group II), and 81.14% (group III), and for replacement were 88.33% (group I), 94.29% (group II), and 71.10% (group III). The reoperation rates for repair were 23.6% (group I), 9.6% (group II), and 8.7% (group III). There were only three reoperations in the replacement group. IN CONCLUSION: (1) the rate of repair is age dependent and inversely related; (2) repair in patients younger than 20 years of age carries a high reoperation rate; and (3) in this age group there is a higher survival tendency.

Adolescent↗
PubMed1994

Pulmonary autograft for aortic valve replacement in rheumatic disease--an ideal solution?

The use of pulmonary autograft for aortic valve replacement (Ross procedure) offers an excellent option for the younger patient with its potential for growth and long term viability. We report our experiences of 61 patients with a mean age of 17.0 years undergoing Ross procedure over a four year period. Rheumatic disease was the cause of aortic valve disease in 48 (79.0%) patients. Mitral valve surgery was required in 18 (29.5%) patients. There was no hospital death, endocarditis or thromboembolism in the series. There was one late death from non-cardiac cause and three (4.9%) reoperations. Two of the reoperations were for progressive autograft regurgitation whilst the third was for mitral valve repair failure. Echocardiographic profiles of 37 of these patients followed beyond six months after surgery show a tendency towards progression of the autograft regurgitation. The long term effects of rheumatic disease on the transplanted valves remain to be evaluated.

Adolescent↗
PubMed1994

Non-prosthetic aortic valve surgery.

Due to significant improvements in myocardial protection, old techniques are being re-explored today in search for the ideal solution for aortic valve disease. We reviewed all patients who underwent non-prosthetic aortic valve surgery between July 1988 and March 1994. There were 361 such patients with a mean age of 22.18 years, mean preoperative functional class of 2.65 and sinus rhythm in 89.75%. The etiology was rheumatic in 65.65% and congenital in 26.37%. Simultaneous mitral surgery was performed in 44% of the cases with repair in 76.73%. A homograft was used in 11 patients with one hospital death, no late deaths and no reoperations. A pulmonary autograft was used in 58 with no hospital deaths, one (1.72%) late death (car accident) and three (5.17%) reoperations due to progressive regurgitation in two. Reconstruction with pericardium was performed in 76 patients with no hospital deaths, three (3.95%) late deaths (one car accident) and four (5.26%) reoperations due to endocarditis in two and valve failure in two. Repair was done in 216 patients with eight (3.7%) hospital and nine (4.32%) late deaths, and 25 (12%) reoperations. Excluding those patients with mitral surgery, there were no thromboembolic events with only two patients (1.02%) anticoagulated. The total actuarial survival was 91.76 +/- 2.40% at 66 months. It is concluded that non-prosthetic aortic valve surgery offers a very attractive alternative for our patient population.

Adult↗
PubMed1994

Chemical assay of glutaraldehyde incorporation into pericardial tissue.

This paper describes the development of a chemical assay to determine the incorporation of glutaraldehyde into pericardial tissue. The procedure is based upon the hydrolysis of the Schiff's bases formed between the glutaraldehyde and the E-amino groups of lysine, the liberated glutaraldehyde being determined as its 2,4-dinitrophenyl-hydrazone by high performance liquid chromatography (HPLC). The HPLC system uses a reverse phase column eluted with a gradient of aqueous acetonitrile (from 60%-70% over 30 minutes). The glutaraldehyde 2,4-dinitrophenylhydrazone is detected at 356 nm. The results show that the assay has sufficient sensitivity (minimum detectable limit 20 pmol of glutaraldehyde 2,4-dinitrophenyl-hydrazone) and reproducibility (+/- 9% at 100 pmol +/- 4% at 1 nmol) to estimate glutaraldehyde incorporation into pericardial tissue. A series of subsequent experiments have documented that temperature and buffer pH are the main determinants affecting glutaraldehyde incorporation into pericardial tissue. Immersion of pericardial tissue in glutaraldehyde solution of pH 9 and 37 degrees C yields an approximately six times greater incorporation than can be achieved if the reaction is performed at 0 degrees C. Further study is underway to relate the amount of Schiff's base bound to that of total incorporated glutaraldehyde.

Animals↗
PubMed1994

Glutaraldehyde, gamma-carboxyglutamic acid and calcium in explanted bioprosthetic heart valves.

This paper describes the determination of glutaraldehyde, gamma-carboxylglutamic acid (gamma-CGA) and calcium concentrations in nine bioprosthetic heart valves after explantation. The glutaraldehyde and gamma-CGA were determined by high performance liquid chromatography (HPLC) procedures and the calcium by atomic absorption spectrometry. Glutaraldehyde was detectable in only two of these valves at levels of 17% and 2% of that present in an unimplanted valve. The results indicate that there is no correlation between gamma-CGA and calcium deposition, indicating that the gamma-CGA is probably absorbed onto the forming calcium deposit from the circulation and does not contribute to the calcification process, and that the acid hydrolysable glutaraldehyde decreases with time during implantation. There is, however, no correlation between the duration of implantation and the decrease in glutaraldehyde concentration.

1-Carboxyglutamic Acid↗