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Biomedical subjects

C G Duran

Publications and source records attributed to C G Duran.

28 records · Page 2Linked to original sources
PubMed1980

Hemodynamic factors that affect calculated orifice areas in the mitral hancock xenograft valve.

From June 1974 to December 1978, 714 Hancock valves have been placed in 605 patients. One hundred seventy-five patients with a mitral xenograft have been restudied. The results were questionable due to the wide scatter and disparity between the calculated and the theoretical orifice of each valve size. To elucidate these differences, the hemodynamic data of 40 isolated, normal functioning mitral Hancock valves were reviewed. Early, middle and late diastolic mitral valve gradients were measured by planimetry and their corresponding flows were estimated by angiography. The paired data were fitted to exponential functions and specific lines for each Hancock valve size were obtained. By superimposing Gorlin's pressure and flow curves on these lines, the instantaneous effective orifice for each Hancock valve can be determined. We concluded that 1) the Hancock valve effective orifice is flow related and always lower than its theoretical opening; 2) normal function frequently cannot be firmly established by the mean effective area; and 3) the nomogram described may help in determining the time-related variations of a particular valve.

Adult↗
PubMed1980

Conservative operation for mitral insufficiency: critical analysis supported by postoperative hemodynamic studies of 72 patients.

From May, 1974, through December, 1978, 255 mitral annuloplasties have been performed at our institution. Forty-three Carpentier rings and 212 flexible rings were used. Simultaneously, 307 patients with predominant insufficiency were treated with a Hancock bioprosthesis. A critical analysis of the flexible ring group versus the Hancock group is presented: The average ages were 41.3 versus 43.3 years. Preoperatively, 55% versus 60% were in Functional Class III and 9.6 versus 25.4% were in Class IV. The valve lesion was caused by rheumatic disease in 91.2% versus 93.9%. A multiple valve operation was required by 51% versus 60%. There was a significant difference in the operative mortality rates (1.8% versus 11.4%). This difference was maintained for each preoperative functional class and for the isolated and multiple valve groups. There was no significant difference in the late mortality rates (1.4% versus 3.7%). The total actuarial survival rates were of 96.4% and 81% (maximum follow-up times 4.0 and 4.5 years). The incidence of embolism was 2.4% and 4.1% per patient-year, with both groups being subjected to the same anticoagulation policy. The incidence of dysfunctions was equal (3.9% per patient-year). Postoperative hemodynamic evaluation of 72 patients having annuloplasty and 129 patients having Hancock valve replacement showed basal mean transmitral gradients of 10.98 +/- 3.6 and 9.66 +/- 2.73 mm Hg. The average effective orifice areas were 1.93 +/- 0.74 and 2.25 +/- 0.46 cm2. While the bioprosthesis behaves hemodynamically like a flow-related variable orifice, the reconstructed valve orifice is dependent upon its preoperative anatomy. In conclusion, the comparison of flexible ring annuloplasty and Hancock valve replacement for mitral valve disease shows a lower operative mortality for the former and comparable medium-term postoperative course. Since both techniques have a limited durability, longer follow-up periods will soon resolve this controversial issue.

Adolescent↗
PubMed1976

Clinical and hemodynamic performance of a totally flexible prosthetic ring for atrioventricular valve reconstruction.

A new, totally flexible ring for atrioventricular annuloplasty is described. The technique for its insertion closely follows the principles of Carpentier's selective annulus reconstruction [4]. Ninety-nine such rings have been inserted (47 in the mitral and 52 in the triscuspid position); 45 valves were simultaneously replaced. There were 6 (4 hospital and 2 late) deaths. The thromboembolic incidence was 4.8%. No instances of dehiscence or late ring deterioration have been detected. Thirty-four patients have been recatheterized, 19 of them with mitral rings. The mitral gradients and angiographic findings show the correct functioning of the implanted ring. It is concluded that use of this flexible ring, which adapts to the continuous changes of the normal mitral annulus, produces a more physiological type of valve operation.

Adolescent↗
PubMedDate not supplied

Persistent left superior vena cava: a simple technique for adequate drainage during cardiopulmonary bypass.

Persistent left superior vena cava is a frequent anomaly of the systemic venous return and usually drains into the right atrium through the coronary sinus. Inadequate drainage of this vessel during cardiopulmonary bypass can result in complications for the patient and problems for the surgeon. Various methods of draining this vessel, directly or indirectly through the coronary sinus, have been already described. Some surgeons temporarily occlude or even ligate this vessel. We describe here an alternative and simple method to drain this vessel during cardiopulmonary bypass.

Cardiopulmonary Bypass↗
PubMedDate not supplied

Cardiopulmonary bypass in sickle cell anaemia. Report of five cases.

Five patients with sickle cell haemoglobinopathies underwent open heart surgery. At the start of the cardiopulmonary bypass the patient's circulating blood volume was separately drained into a bag, spun down and retransfused into the patient at the end of the operation. Moderate hypothermia, aortic cross clamping, topical hypothermia and cold crystalloid cardioplegia were used in all patients. None of the patients had transfusions in the postoperative period. No macroscopic or microscopic evidence of haemolysis were seen, nor haematuria or other clinical evidence of sickling. There was no evidence of wound infection and all were discharged home at a mean of 12.6 days. It is concluded that in cases of sickle cell anaemia exchange transfusion at the beginning of cardiopulmonary bypass followed by retransfusion of the red cell free blood can be used safely, permitting the performance of standard open heart procedures.

Adolescent↗