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C Duran

Publications and source records attributed to C Duran.

At least 37 records · Page 2Linked to original sources
PubMed1996

Vascular reactivity of arterial coronary artery bypass grafts--implications for their performance.

Specific properties of the vessel wall of arteries employed as coronary bypass grafts are thought to play an important role in the short- and long-term performance of these conduits. Heterogeneity in the endothelial and smooth muscle cell function between different arteries may provide particular vessels with properties which will favor them for use as bypass conduits. The aim of this review is to provide an insight into how the vascular reactivity of presently used arterial conduits varies and to discuss the clinical implications of these findings both in terms of flow modulation in response to physiologic and exogenous vasoactive mediators and long-term patency.

Arteries↗
PubMed1996

HLA antigens in Ameridian groups of two different linguistic families from Colombia.

Serological HLA types (A, B, C, DR and DQ loci) were studied in five different Indian tribes (Cubeo, Tucano, Coreguaje, Embera and Noanama) belonging to two distinct linguistic families. For all the MHC loci, the range of variation among the five tribes was enormous. Two tribes, Cubeo and Tucano, showed a wide spectrum of antigenic specificities which seemed to be due to admixture from non-tribal groups, while in the other three tribes the polymorphisms of various HLA loci showed restricted distributions. The gene frequency data, when converted to a kinship matrix and a two-dimensional eigenvector plot, indicated that members of the same linguistic family tend to have greater genetic affinity.

Colombia↗
PubMed1993

A simultaneous study of Doppler-echo and catheterization in noninvasive assessment of the left ventricular dp/dt.

To confirm the feasibility and accuracy of the method for the noninvasive measurement of the left ventricular dp/dt, 53 patients with mitral regurgitation underwent simultaneous determination of left ventricular dp/dt by continuous-wave Doppler echocardiography and cardiac catheterization. Doppler-determined left ventricular dp/dt is derived from the Doppler mitral regurgitant spectrum by dividing the magnitude of the left ventricular-atrial pressure gradient rise between 1 and 3 m/s of the mitral regurgitant velocity signal by the time taken for this change. Left ventricular dp/dt by Doppler ranged from 629 to 3494 mmHg/s (mean +/- SD, 1971 +/- 785 mmHg/s), and that by catheterization varied between 716 and 3650 mmHg/s (mean +/- SD, 1974 +/- 727 mmHg/s). There was a high correlation (r = 0.93, y = 0.862x + 274.77, SEE = 271 mmHg/s, p < 0.001) of left ventricular dp/dt between the two techniques. It is concluded that left ventricular dp/dt is one of the most commonly used parameters for the evaluation of left ventricular systolic function and that Doppler echocardiography provides a new, accurate and noninvasive method of evaluation.

Adolescent↗
PubMed1993

Noninvasive evaluation of right ventricular and pulmonary artery systolic pressures in patients with ventricular septal defects: simultaneous study of Doppler and catheterization data.

The method for evaluating right ventricular and pulmonary artery systolic pressures by subtracting the systolic pressure gradient across the ventricular septal defect from the cuff systolic blood pressure is documented. To confirm the reliability and accuracy of this method, simultaneous continuous wave Doppler echocardiography and left and right cardiac catheterization were performed in 66 patients with congenital ventricular septal defects. The comparisons between the Doppler-derived right ventricular or pulmonary artery systolic pressures and those measured by catheterization yielded an excellent correlation (r = 0.969, y = 1.035x - 3.627, SEE = 8.2 mm Hg, p < 0.001 and r = 0.972, y = 1.012x - 2.904, SEE = 7.6 mm Hg, p < 0.001), respectively. There was a close agreement between the Doppler-derived right ventricular or pulmonary artery systolic pressures and those measured by catheters, and the differences between the two measurements did not differ significantly from zero. It is concluded that Doppler echocardiography offers a reliable and accurate method for noninvasive assessment of right ventricular and pulmonary artery systolic pressures in patients with ventricular septal defects.

Adolescent↗
PubMed1993

Transcatheter laser atrial septostomy in rabbits.

The feasibility of percutaneous transluminal catheter-directed laser (Argon multiline 488/514 nm) atrial septostomy under echocardiographic guidance was studied in eight rabbits. In five animals the interatrial septum was exposed to laser energy for 30 s (n = 1) or for 10 s (n = 4) by using the continuous wave (cw) mode of irradiation. In the other three animals chopped mode of irradiation was applied for 10 s at 7 W. Echocardiography allowed visualization of both atrial cavities and the interatrial septum, the tip of the catheter including the optical fiber tip as well as the flow direction of contrast echoes during the laser firing. Blood clotting with thrombus formation was present following the cw mode of irradiation. The defects created in the interatrial septa of < or = 0.3 mm in diameter had irregular black borders and, histopathologically, were surrounded by a zone of coagulation necrosis of < or = 0.2 mm and vacuolization (vacuoles of < 0.1 mm in diameter). After 30 s of lasering a huge defect was conspicuous in the interatrial septum which extended up to the right and left atrial roof. The chopped mode of irradiation induced less blood clotting and narrow channels of < or = 0.08 mm through the interatrial septa with a small zone of coagulation necrosis of < or = 0.05 mm and without carbonization and vacuolization. This study demonstrates that laser atrial septostomy is technically feasible. However, prior to the extension of the method to humans, further investigation especially considering other laser power sources, possibly more suitable for this application such as Neodymium-YAG or Excimer lasers is warranted.

Animals↗
PubMed1991

Indications and limitations of aortic valve reconstruction.

To elucidate the value of conservative operation for aortic regurgitation, all consecutive patients operated on between July 1988 and July 1990 were reviewed. Of 251 patients with aortic regurgitation, 107 (42.6%) had nonprosthetic operation. The mean age was 23 years, and 90 patients (84.1%) were rheumatic. Two techniques were used: repair (annular and leaflet plasties, 69 cases) and cusp extension with glutaraldehyde-treated pericardium (25 bovine, 13 autologous). There were two hospital deaths (1.8%), both in the repair group, and no late deaths or embolic events. Only 5 patients (4.7%) were anticoagulated. In the repair group there were 12 reoperations, four (5.9%) due to aortic and eight to mitral dysfunction. In the cusp extension group there were two reoperations due to mitral dysfunction. Echocardiographic follow-up showed better results with cusp extension. In conclusion, conservative operation for aortic regurgitation is possible in a high percentage of young rheumatic patients and does not require anticoagulation. Cusp extension is more reliable than repair in terms of early results, although its long-term durability is not yet known.

Adolescent↗
PubMed1990

Actinic prurigo among the Chimila Indians in Colombia: HLA studies.

The Chimila, a Colombian Amerindian group that lives at a low altitude, have a high incidence of actinic prurigo. We present the human lymphocyte antigen (HLA) findings of 43 Chimilas with the disease and of 62 control subjects and show an association of actinic prurigo with the Cw4 antigen.

Adult↗
PubMed1990

Surgical approaches to the mitral valve.

Different approaches to the left atrium and various techniques of the atriotomy are practiced by cardiac surgeons according to the need for a particular patient and preference of the individual surgeon. Their basic methods, advantages and disadvantages, and our present day techniques are discussed.

Aorta↗