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Biomedical subjects

C Brizard

Publications and source records attributed to C Brizard.

17 recordsLinked to original sources
PubMed2004

Experience with the Jostra Rotaflow and QuadroxD oxygenator for ECMO.

Since April 1988, we have been able to offer extracorporeal membrane oxygenation (ECMO) to patients who are either failing ventilation or who need cardiopulmonary support following cardiac surgery. During this time, we have supported 211 patients, the majority of whom have been supported with the Avecor (Affinity, Avecor Cardiovascular Inc., Minneapolis, MN, USA) spiral wound silicone-membrane oxygenator. Microporous hollow-fibre oxygenators have been used (18%) at our center. However, due to their early failure, they have necessitated conversion to a device that potentially would last for the entire ECMO course, i.e., Avecor and, subsequently, have not been used routinely until the introduction of the QuadroxD (Jostra Medizintechnik AG, Hirrlingen, Germany). The recent development of the poly-4-methyl-1-pentene diffusion membrane allows us to utilize hollow-fibre technology with a true (nonmicroporous) membrane. This has enabled us to use this low-resistance device with all its inherent advantages, without plasma leakage necessitating circuit changeover. From July 2000, we have used the QuadroxD oxygenator for our patients requiring ECMO support. This has been in patients with weights ranging from 2.16-51.0 kg (n = 23), with the longest support being for 1119 hours. This new technology has enabled us to utilize a single device for all patient sizes, so we now have an ECMO circuit set up at all times, minimizing the time required for support to be available, potentially improving survivor morbidity.

Cardiac Surgical Procedures↗
PubMed2004

Pump-induced haemolysis: a comparison of short-term ventricular assist devices.

Centrifugal pumps are superior to roller pumps for extended support durations in terms of pump-induced haemolysis. In this study, we evaluated the commonly used Biomedicus BP 50 and compared it with the Jostra Rotaflow and a standard roller pump in an in vitro test circuit. Each circuit was run for a six-day period and repeated five times. Plasma haemoglobin values showed the roller pump to become more haemolytic than the Biomedicus (p = 0.022) and the Rotaflow. A statistically significant difference between the Biomedicus and the Rotaflow was observed on day six of the trial (p = 0.016), with the Rotaflow showing lower levels of haemolysis than the Biomedicus. These results support the use of the new generation centrifugal pump, the Rotaflow, as a suitable device for short-term ventricular assist.

Assisted Circulation↗
PubMed2000

Clinical features and management of isolated cleft mitral valve in childhood.

OBJECTIVES: We reviewed an institutional experience of isolated cleft mitral valve (ICMV), its clinical features, and management in a pediatric population. BACKGROUND: As ICMV is relatively uncommon, earlier reports highlighted its anatomical and echocardiographic features. Few studies have collated their clinical features with their outcome. METHODS: All patients with ICMV were retrospectively reviewed. Patients who were considered to have an atrioventricular septal defect or variant were excluded. RESULTS: Twenty patients (9 male, 11 female) were diagnosed with ICMV. Seven patients had associated cardiac lesions. The median age of diagnosis was 5.2 years (range 0.4 to 13.6 years). Echocardiography aided by color Doppler demonstrated the ICMV in all patients. However, an incomplete diagnosis was made in 4 of 20 patients before surgery. The severity of the mitral regurgitation (MR) at presentation was mild in 11, moderate in 8, and severe in 1 patient. In the 13 patients without associated cardiac lesions, 5 underwent mitral valve (MV) repair at median age of 5.2 years (range 1.2 to 7.7 years) for moderate to severe MR, 4 being symptomatic. The severity of the MR in seven of the eight unoperated patients has remained unchanged over the follow-up period (median 8.3 years, range 0.7 to 14.4 years). In total, 10 patients underwent MV repair (median 6.4, range 0.4 to 13.8 years). No patient required MV replacement. None of the 10 patients had more than mild MR over the follow-up period (median 0.6, range 0.2 to 11.0 years). CONCLUSIONS: Now readily diagnosable by echocardiography, ICMV is a correctable cause of MR with a good outcome. Surgery is indicated in those patients with moderate to severe MR and probably should be done early following diagnosis.

Adolescent↗
PubMed1997

[Conservative surgery in rheumatic aortic insufficiency].

The mechanism of rheumatic aortic regurgitation is retraction of the three cusps leading to lack of coaptation. The authors describe a technique of aortic valve repair by extension of the cusps using autologous pericardium, undertaken in 52 patients (mean age 21 +/- 5 years) and report the short and medium term results. There were no operative deaths or reoperation for technical failure. The postoperative echocardiographic examinations showed absent or minimal aortic regurgitation in 45 patients (87%) and moderate regurgitation in 7 patients (13%). The echocardiographic results at 2 years were stable: no patient was reoperated for deterioration of the valvuloplasty. This technique is reproducible and reliable is selected patients.

Adolescent↗
PubMed1996

Angiographic and electron-beam computed tomography studies of retrograde cardioplegia via the coronary sinus.

Retroperfusion of the coronary sinus does not provide homogeneous distribution of cardioplegic solution. The goal of this study was to analyze the distribution of flow during retrograde cardioplegic infusion in cadaveric human hearts with two different techniques of coronary sinus cannulation: (1) internal occlusion of the coronary sinus by balloon inflation and (2) external occlusion by tightening the orifice of the coronary sinus around a simple catheter. To evaluate differences between the two techniques, angiographic and electron-beam computed tomographic studies were performed. Computed digital angiography was performed on 14 hearts. Angiographic patterns varied according to type of coronary sinus cannulation. With the balloon inflation technique, the marginal vein and the anterior descending vein were perfused first; the posterior descending vein was not perfused. This vein was opacified secondarily through a venovenous anastomosis located at the apex of the heart. Backward flow into the right atrium (steal phenomenon) was demonstrated. At completion of retroperfusion, the inferior part of the septum remained poorly opacified. Conversely, angiographic findings after external occlusion of the coronary sinus revealed simultaneous injection of all venous channels. The entire septum was well opacified at completion of retroperfusion. Electron-beam computed tomographic study was performed on eight hearts with the external occlusion technique and nine with the internal occlusion technique. The computed tomographic findings confirmed the results of digital angiography. The peak myocardial enhancement and the peak rising rate of myocardial enhancement within the interventricular septum were significantly more important (p < 0.0001) when the external coronary sinus occlusion mode was used than when the internal coronary sinus occlusion mode was used. In all hearts except one, the right ventricular wall was not opacified, regardless of the type of cannulation and the type of radiologic analysis. This study demonstrates the importance of coronary sinus cannulation technique in optimizing the protection of the interventricular septum with retrograde cardioplegic infusion.

Adult↗
PubMed1994

Downsizing of valve allografts for use as right heart conduits.

In recent years, there has been a worsening shortage of small and intermediate-sized aortic and pulmonary allografts for use as right ventricular-to-pulmonary artery conduits in infants and children. However, there is a surfeit of large pulmonary and aortic allografts from adult donors. The feasibility of reducing a large allograft to a more useful size was examined using human pulmonary and aortic allografts. Eleven pulmonary allografts (11 to 26 mm in diameter) and nine aortic allografts (5 to 27 mm in diameter) were studied. Valve competence before downsizing was tested with a column of saline to a static pressure equivalent to the normal pulmonary pressure (20 mm Hg). Regurgitant flow was measured for 15 minutes. One complete cusp of the valve was excised, together with a longitudinal strip of the arterial wall. A bicuspid valved conduit was created by suturing the allograft longitudinally. The diameter of the bicuspid valve was measured with a dilator. A nomogram was constructed that predicts the size of the bicuspid allograft based on the size of the original allograft. The competence of the bicuspid allograft was tested and the regurgitant flow was compared with that of the original tricuspid allograft. The transvalvular systolic pressure gradient was measured with the bicuspid allograft placed in a pulsatile extracorporeal perfusion circuit at a flow rate of 1 L/min and a mean pressure of 20.5 +/- 2.6 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Mitral valve replacement with cryopreserved mitral homograft].

Mitral valve replacement using a cryopreserved mitral homograft was performed in a 49 year old patient with calcified mitral stenosis. The surgical technique is described. The postoperative course was uneventful. Transoesophageal echo performed 4 months later showed a normal function of the mitral homograft.

Chordae Tendineae↗
PubMed1993

Cardiac hemangiomas.

Cardiac hemangiomas are rare benign vascular tumors of the heart. To date, 23 cases have been reported. Symptoms are usually due to compression of cardiac structures or obstruction of outflow tracts. Echocardiography usually directs the diagnosis toward a cardiac mass. Enhanced-contrast computed tomographic scan or magnetic resonance imaging establishes the diagnosis of hypervascularized cardiac tumor. Coronary arteriography establishes the diagnosis by showing the characteristic tumor blush. Surgical resection is done using cardiopulmonary bypass. Long-term outcome is favorable.

Adult↗
PubMed1993

Left ventricular outflow tract obstruction after mitral valve repair. Results of the sliding leaflet technique.

BACKGROUND: Left ventricular outflow tract obstruction (LVOTO) occurs in 4% to 5% of patients after prosthetic ring mitral valve repair. Major anatomic factors incriminated in the genesis of LVOTO include degenerative mitral valve insufficiency with excess leaflet tissue, nondilated left ventricular cavity, and narrow mitro-aortic angle. We have previously reported a 14% incidence of LVOTO after prosthetic ring mitral valve repair in this high-risk group of patients. Serial echo Doppler studies demonstrated an overlapping and/or inversion of the left ventricular functional compartments generating systolic anterior motion of the posterior leaflet and paradoxical opening (eversion) of the anterior leaflet. In an attempt to eliminate LVOTO after mitral valve repair, a new surgical procedure was developed in 1988 by Carpentier: the sliding leaflet technique, which reduces the height of the posterior leaflet. The purpose of this study was to analyze the results of the new technique in terms of the occurrence of LVOTO: METHODS AND RESULTS: Eighty-two patients undergoing prosthetic ring mitral valve repair between 1988 and 1991 and identified as high risk for LVOTO were operated on using the sliding leaflet technique. There were 52 men and 30 women. Ages ranged from 28 to 75 years. The surgical techniques used included prosthetic ring annuloplasty (n = 82), leaflet resection (n = 82), chordal shortening or transposition (n = 36), and other (n = 19). Intraoperative and/or immediate postoperative echo Doppler studies were obtained in all cases. Two patients (2.4%) died, and 2 (2.4%) required reoperation. Nonsignificant LVOTO was identified in 2 cases (2.4%), in whom instantaneous maximal subaortic gradients were 20 and 18 mm Hg, respectively. CONCLUSIONS: This study was not done on a concomitant series of patients but on patients with the same type of pathology. It demonstrates that (1) the sliding leaflet technique eliminates significant LVOTO in the high-risk patients; (2) the sliding leaflet technique is associated with a low mortality; and (3) no reoperations for mitral insufficiency were required in this series.

Echocardiography, Transesophageal↗
PubMed1992

[Mycotic aneurysm of the carotid artery secondary to acute bacterial endocarditis].

Mycotic aneurysms of the extracranial carotid arteries are rare. A new case of mycotic aneurysm of the bifurcation of the carotid artery secondary to acute bacterial endocarditis affecting the aortic valve is reported. Simultaneous treatment of the two lesions was instituted. The twenty six cases of mycotic aneurysm of the extracranial carotid arteries previously described in the literature are reviewed by the authors.

Aneurysm, Infected↗
PubMed1991

[Chromosome anomalies in brain tumors].

The authors review the literature concerning chromosomal abnormalities in childhood brain tumors: medulloblastomas, ependymomas, and gliomas of low and high grade. Though these technics require further development, they highlight the role of cytogenetic modification in oncogenesis of brain tumors.

Astrocytoma↗
PubMed1990

Repeated surgery for recurrent dissection of the aorta.

Emergency surgery of acute dissection of the ascending aorta is generally a palliative procedure aimed at preventing the vessel from rupturing into the pericardium. Evolving dissecting aneurysm or recurrence of the dissection process is, therefore, a common complication and may lead to reoperation or death. Between January 1970 and December 1988, 133 patients were operated upon for acute dissection of the ascending aorta. During the same period, 22 patients underwent 26 reoperations for recurrent or evolving dissection. Eleven (50%) patients had Marfan's syndrome. Thirteen patients had been operated upon previously in our institution and 8 had been operated upon elsewhere. In 10 patients, the intimal tear had not been resected during the first operation. Operative procedures varied according to the pathoanatomical features and consisted generally of an extended resection of the aortic arch. Eight reoperations were performed as emergencies and 18 were performed electively. Hospital mortality rate was 18% (4/22). Late follow-up ranged from 3 to 153 months (mean: 55 months) for a cumulative follow-up of 998 months. Late mortality was 27% (5/18) for a linearized rate of 6% pt/yr. The actuarial risk of reoperations is 13.7% +/- 7% and 21% +/- 11% at 5 and 10 years, respectively. Marfan's syndrome and persistence of the primary intimal tear are considered the main risk factors of reoperation, while emergency and thoraco-abdominal replacement are the main risk factors at reoperation.

Adult↗
PubMed1987

Hemoglobin Grange-Blanche [beta 27(B9) Ala----Val], a new variant with normal expression and increased affinity for oxygen.

Hemoglobin Grange-Blanche [beta 27(B9) Ala----Val] is a new variant found in a Portuguese family. The carriers present moderate erythrocytosis. Upon isoelectric focusing, Hb Grange-Blanche was slightly more cathodic than Hb A. beta Grange-Blanche chain migrated like the G gamma chain when submitted to electrophoresis in the presence of urea-Triton X-100. The precentage of Hb Grange-Blanche was about 50% in the heterozygous state. Oxygen affinity was increased (P50 = 22 mmHg), but heme-heme interaction was normal. An abnormal tryptic peptide (beta T3) was isolated using HPLC. Its composition allowed us to deduce unambiguously the amino acid change. The latter is the third mutation found in position 27 of the beta-chain. Because of its normal expression and its elevated affinity for oxygen, Hb Grange-Blanche contrasts with Hb Knossos [beta 27(B9) Ala----Ser], a beta-thalassemic variant with low affinity.

Adult↗