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Biomedical subjects

C G Duran

Publications and source records attributed to C G Duran.

At least 19 recordsLinked to original sources
PubMed1994

Ischemic mitral valve disease: classification and systemic approach to management.

One hundred sixty-nine consecutive patients with coronary artery disease and mitral valve pathology operated during the past 5 years were reviewed (98% follow-up). Eighty-seven patients underwent mitral valve repair and 82 mitral valve replacement with concomitant coronary artery bypass grafting (number of AV grafts = 3). An analysis of these patients (age range 48 to 92 [mean 69]) and a classification based on anatomic pathology of the mitral apparatus is presented. Flexible ring annuloplasty was utilized in all repairs and chordal-sparing techniques in all valve replacements. There was equal mortality for replacement and repair in this subset of high risk patients. Structural valve dysfunction of repaired valves was more common (5/81 [6.0]) than primary tissue valve failure after mitral valve replacement (0 patients).

Aged↗
PubMed1993

A new expandable intracoronary tantalum (Strecker) stent: early experimental results and follow-up to twelve months.

A new radiopaque balloon expandable tantalum stent was tested in the coronary arteries of sheep. A total of 28 stents with a diameter of 2.0 to 3.8 mm were successfully deployed. The stent to coronary artery diameter ratio was 1.1-1.2:1. The animals were heparinized with 100 U/kg of heparin but did not receive antiplatelet drugs. Coronary angiography that was performed 10 minutes after stent implantation showed 100% patency with no side-branch occlusion. Four sheep died within 2 hours of stent implantation, and pathologic studies showed thrombosis of the smaller sized stents: 2 mm (n = 2), 2.8 mm (n = 1), and 3.2 mm (n = 1); three fourths of the sheep had two stents implanted. An oversized stent caused coronary rupture and cardiac tamponade in one other sheep. Follow-up study protocol included coronary angiography before animal sacrifice and pathologic studies within 48 hours (n = 11), 2 weeks (n = 1), 3 months (n = 2), 5 months (n = 1), 10 months (n = 7), and 12 months (n = 1). At 3 to 12 months of follow-up the coronary stent was completely covered with a layer of neointima, and there was no angiographic evidence of coronary stenosis and patent side branches. According to histologic examination, the neointima had nonuniform thickness (20 to 330 microns) and consisted of smooth muscle cells and some collagen. At 7 months of follow-up one of seven stents had angiographic (20%) and pathologic evidence of stenosis, which was secondary to thrombus. The tantalum device is easily deployed technically and notable for its excellent fluoroscopic visibility and flexibility. Thrombosis with a tantalum stent remains a problem, and therefore the larger diameter stents > or = 3.2 mm, antiplatelet drugs, and anticoagulation therapy are indicated for human studies. Implantation of multiple coronary stents increases the risk of stent thrombosis. The long-term, mild neointimal thickness and the patency of the stent and side branches are encouraging.

Animals↗
PubMed1993

Mitral restenosis and mitral regurgitation 1 year after Inoue mitral balloon valvotomy in a population of patients with pliable mitral valve stenosis.

To determine the rate of mitral restenosis and mitral regurgitation increase 1 year after mitral valvotomy using the Inoue balloon catheter, 66 consecutive patients with severe, pliable mitral stenosis had their mitral valve area (MVA) calculated by two-dimensional echocardiography (2DE) and Doppler before, immediately after balloon valvotomy, and at 1-year follow-up. Color Doppler studies were also done to detect small atrial septal defects (ASDs) and mitral regurgitation. The mean age of the patients was 31 +/- 12 years. Three patients were in New York Heart Association (NYHA) class II and 63 patients were in NYHA class III to IV. Sixty-two of the 66 patients had an echo score (Boston) of < or = 8. After Inoue balloon valvotomy (IBV), the MVA (2DE) increased from 0.8 +/- 0.2 to 1.9 +/- 0.3 cm2 (p < 0.001), and the Doppler MVA increased from 0.8 +/- 0.2 to 1.8 +/- 0.3 cm2 (p < 0.001). We detected 4 of 66 cases (6%) with significant residual mitral stenosis (MVA < 1.5 cm2). Mitral regurgitation increased in 14 of 66 patients (21%), but no patient developed severe mitral regurgitation. Fourteen out of 66 patients (20%) had ASDs that were detected on color Doppler. At 1-year follow-up the mean Doppler MVA was maintained at 1.8 +/- 0.4 cm2, with 6 of 66 patients (9%) exhibiting significant mitral valve restenosis. Residual significant mitral stenosis must be differentiated from mitral restenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Balloon valvotomy for pregnant patients with severe pliable mitral stenosis using the Inoue technique with total abdominal and pelvic shielding.

Balloon valvotomy by means of the Inoue technique was attempted in seven pregnant (5 to 9 months) patients with severe mitral stenosis; the mean age of the patients was 32 +/- 8 years, and all had a two-dimensional echocardiographic mitral valve score of < 8. Indications for Inoue balloon valvotomy included severe symptomatic mitral stenosis with a Doppler mitral valve area < or = 1 cm2 and heart failure refractory to medical therapy, or absolute contraindications for the use of beta-blockade; Inoue valvotomy was also indicated for patients who lived a long distance from the hospital. Inoue balloon valvotomy was performed with no angiography and total pelvic and abdominal shielding; the balloon catheter was introduced into the right atrium without the aid of fluoroscopy, which was used for the transseptal puncture. Stepwise two-dimensional echocardiographic Doppler mitral valve dilatation was done. After Inoue balloon valvotomy the mean Doppler mitral valve area increased from 0.8 +/- 0.1 to 2.0 +/- 0.3 cm2 (p < 0.01) and by two-dimensional echocardiography from 0.8 +/- 0.2 to 1.9 +/- 0.3 cm2 (p < 0.01), with no significant Doppler residual stenosis (defined as mitral valve area < or = 1.5 cm2). The mean total fluoroscopy time was 16 +/- 7 minutes. The degree of mitral regurgitation increased in two patients from grade 1+/4+ to grade 2+/4+ and from grade 0+/4+ to grade 2+/4+, respectively. There was no mortality or significant morbidity. Pregnancy was uneventful in all patients, and all were delivered of normal babies without complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1990

Haemodynamic effect of supraaortic ridge enhancement on the closure mechanism of the aortic valve and its implications in aortic valve repair.

The presence of the sinus of valsalva plays an essential part in the closing mechanism of the aortic valve. High-energy vortices are initiated at the upper limit of each sinus or supraaortic crest, and last during the whole valve closing time. An attempt was made to prove this hypothesis in vivo by intermittent augmentation of each supraaortic ridge. In a series of five dogs without cardiopulmonary bypass, pledgeted sutures were placed at the level of each crest and passed through tourniquets. In a series of three sheep, similar sutures were placed under direct vision with cardiopulmonary bypass. The supraaortic crests were augmented or maintained normal by tightening or loosening the tourniquets repeatedly. Simultaneous aortic and ventricular pressures and 2D- and M-mode echocardiography were recorded. In the dog series the results were unpredictable due to variability in the supraaortic crest enhancement because the sutures did not correspond to the anatomical crest. In the sheep series the sutures were correctly placed and M-mode echocardiography demonstrated a significant (p less than 0.01) shortening in systolic time. These results suggest the use of enhancement of the supraaortic crest as an adjunct technique in aortic valve repair.

Animals↗
PubMed1989

Twenty-year comparison of the human allograft and porcine xenograft.

This study compares a retrospective consecutive series of human allografts and concurrent porcine xenografts implanted over a 10-year interval. There were 571 allograft valves and 1,351 xenograft valves implanted in the aortic and mitral position with mean follow-up of 12.8 years for the allografts and 6.2 years for the xenografts. This study compares the incidence of structural deterioration over long-term follow-up. We found that there was no significant difference between four manufacturers of porcine xenografts, in spite of substantial differences in processing techniques. We found that there was a significant difference in allografts that were premounted on stents as compared with allografts that were not premounted on stents for aortic valve replacement. We found that there was no significant difference between allografts for aortic valve replacement that were not premounted on stents and porcine xenografts implanted in the aortic position. These findings are in marked contrast to those of other reported series with the use of allograft valves.

Animals↗
PubMed1988

Reconstructive techniques for rheumatic aortic valve disease.

Aortic valve reconstruction is still at an early stage of development. We report techniques that can be applied in the repair of rheumatic aortic valve disease in patients with concomitant mitral valve disease. The techniques described are: (1) commissurotomy, (2) cusp free edge unfolding, (3) annuloplasty, and (4) supraaortic crest enlargement. Fifty patients operated on between January 1974 and January 1986 with a hospital mortality of 6% were followed for a mean period of 7.7 years. Reoperation due to failure of mitral surgery was required in twelve patients, tricuspid regurgitation in two, and significant aortic regurgitation in four. These techniques, although applicable to a limited number of patients, have enabled us to avoid the problems of aortic valve replacement in many patients.

Adolescent↗
PubMed1988

Long-term evaluation of the Ionescu-Shiley pericardial xenograft bioprosthesis in the aortic position.

From August 1977 through October 1984, 241 patients underwent aortic valve replacement with the Ionescu-Shiley pericardial valve. There were 130 males and 11 females in this series with an average age of 50.8 years (range 15 to 78 years). Isolated aortic valve replacement was performed in 121 patients (50.2%) and associated cardiac surgery in 120 (49.8%). Valve size was 21 mm or smaller in 107 cases (50.2%). Cumulative duration of follow-up was 1,260 patient-years with a mean follow-up of 5.16 years per patient. Five patients were lost to follow-up. Maximum follow-up was 10.5 years. There were 26 hospital deaths and 15 late deaths (1.19% per pt-yr). The expected 10.5 year actuarial survival rate is 82% +/- 2.9%. Twelve thromboembolic episodes occurred in seven patients--seven central and five peripheral events. The thromboembolic rate was 0.95% per patient-year--32% for patients with isolated aortic valve replacement and 0.63% for patients with concomitant surgery. Freedom from thromboembolic episodes at 10.5 years is 73% +/- 12%. Structural valve deterioration was found in 24 patients (1.9% per pt-yr) with an actuarial freedom from primary tissue failure of 77.5% +/- 5.4% at 10.5 years. Reoperation was required in 39 cases (3.09% per pt-yr)--primary tissue failure (n = 24), paravalvular leak (n = 7), infective endocarditis (n = 6), and valve thrombosis (n = 2).

Adolescent↗
PubMed1985

Late clinical results with the use of heterologous pericardium for closure of the pericardial cavity.

In a limited series of 87 patients, the pericardial cavity was closed with a patch of heterologous glutaraldehyde-preserved pericardium. Five specimens have become available for macroscopic and microscopic study, with a postimplant time ranging between 1.5 and 59 months. The patches maintained their initial structure, but the reaction over the epicardial area facing the graft greatly impeded the recognition of the coronary vessels.

Bioprosthesis↗
PubMed1985

Incidence of primary tissue valve failure with the Ionescu-Shiley pericardial valve. Preliminary results.

This report provides retrospective follow-up data on 88 patients who received an Ionescu-Shiley bovine pericardial valve in the aortic position between August, 1977, and June. 1980. Seven instances of primary tissue degeneration occurred in seven of the 65 patients followed up until June, 1984. Cumulative duration of follow-up was 335.5 patient-years. The linearized incidence of primary tissue failure was 2.08% per patient-year. The actuarial rate of freedom from valve failure for patients with an Ionescu-Shiley valve in aortic position was 79% +/- 8% at 7 years of follow-up. This series shows a higher incidence of primary tissue failure with this prosthesis than with the glutaraldehyde-preserved porcine xenograft in the aortic position at 7 years' follow-up.

Adolescent↗
PubMed1984

The Ionescu-Shiley valve: a solution for the small aortic root.

Valve replacement in patients with a small aortic anulus can cause difficult technical problems or leave the patient with a significant residual transvalvular gradient. Between August, 1977, and June, 1983, 35 patients with a small aortic root (21 mm or less) underwent aortic valve replacement with Ionescu-Shiley pericardial xenograft valves. They ranged in age from 29 to 76 years (mean 52.8 years) and in weight from 64 to 91 kg (mean 76.3 +/- 3.6 kg). Preoperatively, 26 patients were in New York Heart Association Functional Class III-IV. The valve sizes used were 17 mm in three cases, 19 mm in 16 cases, and 21 mm in 16 cases. There were four hospital deaths (11.4%) resulting from sepsis or low cardiac output. There were no late deaths. Cumulative duration of follow-up was 819.4 patient-months. Twenty-four (78%) of the 31 surviving patients are asymptomatic. Up to the time of review, there have been no episodes of thromboembolism, infective endocarditis, perivalvular leak, valve thrombosis, or primary tissue valve failure. Fifteen patients were hemodynamically evaluated 2 to 47 months (mean 14.3 months) after operation. The average resting transvalvular gradients for 19 and 21 mm valves were 15.1 and 10.8 mm Hg, respectively. Our experience suggests that the Ionescu-Shiley pericardial xenograft valve is a valid alternative in the surgical treatment of patients with a small aortic root.

Adult↗
PubMed1983

Analysis of the amount of tricuspid valve anular dilatation required to produce functional tricuspid regurgitation.

To determine the critical anular dilatation required for functional tricuspid regurgitation (TR) and the role of systolic anular shortening in the severity of TR, 67 patients in whom right ventriculography had been performed were studied. These patients were classified into group I, control (n = 12), and the group II, patients with rheumatic valvular disease (n = 55). Group II patients were subclassified as follows: IIa, without TR (n = 19); IIb, with mild TR (n = 22); and IIc, with moderate to severe TR (n = 14). The angiographic maximal early systolic and minimal end-systolic diameters were measured. The shortening of the tricuspid anulus was expressed as percent reduction of the maximal diameter. The average maximal diameter (mm/m2) was: group I, 21 +/- 2; group IIa, 24 +/- 2; group IIb, 31 +/- 4; and group IIc, 37 +/- 4. The average minimal diameter (mm/m2) was: group I, 15 +/- 2; group IIa, 18 +/- 2; group IIb, 23 +/- 2; and group IIc, 31 +/- 3. The average percent shortening was: group I, 30 +/- 7%; group IIa, 25 +/- 7%; group IIb, 26 +/- 5%; and group IIc, 15 +/- 3%. The rheumatic patients had a larger maximal diameter than did those in the control group. Anular shortening was reduced only in the group with moderate to severe TR and preserved in the other groups, including those with mild TR. The critical diameter was determined to be between the maximal diameter in the rheumatic patients without TR and the minimal diameter in the patients with moderate to severe TR, or 27 mm/m2. Thus this easily measured parameter can determine the presence and significance of functional TR, adding objectivity to the angiographic diagnosis of TR.

Adolescent↗
PubMed1982

Glutaraldehyde-preserved heterologous pericardium for the repair of diaphragmatic defects: experimental study.

Glutaraldehyde-treated porcine and bovine pericardium was used to close diaphragmatic defects in 15 dogs. The animals were reoperated upon between 15 days and 15 months. There were no adherences between the heterologous patch and the adjacent structures in any dogs except one, in which the omentum was attached to the pericardium. Microscopically, the graft structure remained intact without cellular invasion. The graft was covered with a thin layer of fibrous tissue, more intense in the one case of omental adhesions. There were no macroscopic or microscopic differences detectable in the behavior of the bovine and porcine pericardium. Although the follow-up is relatively short, these materials appear to offer a valid nonadherent alternative for diaphragmatic repair.

Animals↗