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Biomedical subjects

A Carpentier

Publications and source records attributed to A Carpentier.

At least 73 records · Page 4Linked to original sources

[Utilization of aortomyoplasty as a biological pumping system].

Aortomyoplasty is a surgical technique of constructing a neo-ventricle on the ascending or descending aorta with the latissimus dorsi muscle. This is electrically stimulated to contract during diastole, thereby creating a system of chronic, haemo-compatible aortic pumping. Long-term experimental studies have shown increases in cardiac output (from 3.6 to 5.5 l/min), decreases in peripheral resistances (from 1574 to 1134 dyne.sec.cm-5) and increases in indices of subendocardial viability (DPTI/TTI: 1.1 to 1.4). These experimental studies have been confirmed by the initial clinical results. To date, world experience includes thirty-six patients. With cardiomyoplasty, aortomyoplasty is a new arm in the therapeutic arsenal against severe cardiac failure by providing a new system of chronic circulatory assistance which is implantable and biocompatible.

Aorta, Thoracic↗

[Human valvular substitutes for the treatment of complex progressive endocarditis. Application to aortic, mitral and tricuspid valves].

The aim of this study was to assess the immediate and long-term results of human valvular substitutes (homografts and autografts) in the treatment of complex progressive endocarditis in aortic, mitral and tricuspid valves. Since 1992, 80 patients (64 men, 16 women) aged 44 +/- 16 years (range 15 to 76 years), were treated. In 53 patients, the endocarditis involved native valves, 4 on previously plastified valves, or prosthetic valves in 27 patients. The endocarditis was recurrent 6 patients. The lesions were situated on the aortic valve (N = 59), mitral valve (N = 5), aortic and mitral valves (N = 12), aortic and tricuspid valves (N = 3), mitral and tricuspid valves (N = 1). The peroperative findings confirmed the lesions diagnosed at echocardiography: prosthetic valve dehiscence (27 patients), prosthetic cusp tear (N = 7), vegetations (N = 61), perforations (N = 48), periannular abscess (N = 47), aorto-ventricular discontinuity (N = 12), aorto-mitral discontinuity (N = 7), right ventricular aortic fistula (N = 1), aorto-pulmonary fistula (N = 1), pseudo-aneurysm (N = 1), ventricular septal defect (N = 1). Eighty-six human valvular substitutes were used (double homograft in 6 patients): aortic homograft (N = 63), pulmonary in the aortic position (N = 1), the mitral position (N = 12), of which 8 were in the mitral and 4 in the tricuspid position, pulmonary autograft (N = 10). Ten mitral valve repairs were performed on infected lesions. Associated procedures included mitral valve repair (N = 5), tricuspid valve repair (N = 1) for non-infarcted valve lesions, replacement of the ascending aorta (N = 2), the aortic arch (N = 1), coronary bypass surgery (N = 2) and one nephrectomy. The hospital mortality was 5% (4 patients). The causes of death were: infarction (N = 2), myocardial failure (N = 1) and multiorgan failure (N = 1). Four early reoperations were required for technical problems, none for endocarditis. Seventy-three of the 76 survivors were followed up for 43 +/- 24 months (range 1 to 84 months). Eight patients died during follow-up, but only 1 of cardiac causes (operation for recurrent endocarditis in a drug abuser). Seven operations were performed, 3 for technical problems or structural failure, 4 for recurrent endocarditis. At 5 years' follow-up, the survival was 81 +/- 5%; 88 +/- 6% of patients were free of endocarditis, 77 +/- 6% had no reoperation: no patient had thromboembolic complications. These results show that human valvular substitutes are adapted for the treatment of complex, progressive aortic, mitral and tricuspid valve endocarditis when techniques of valvular repair are no longer feasible.

Adolescent↗

[Pre and Postoperative evaluation of the incidence of arrhythmia in patients undergoing corrective intervention for Ebstein anomaly].

BACKGROUND: Patients with Ebstein's anomaly frequently have troublesome cardiac arrhythmias. In particular, this malformation is the most common congenital defect associated with the Wolff-Parkinson-White syndrome. The aim of this study was to investigate the postoperative evolution of arrhythmias without the aid of any surgical techniques for arrhythmia. METHODS: Between 1980 and 1999, 48 patients (22 males, 26 females), with a preoperatively documented arrhythmia, underwent an operation for the correction of Ebstein's anomaly at the Hôpital Broussais. Of these, 24 had paroxysmal supraventricular tachycardia, 12 had atrial fibrillation or flutter, 8 had Wolff-Parkinson-White syndrome, 1 had non-sustained ventricular tachycardia, and the remaining 3 patients had atrioventricular block. RESULTS: The operative mortality was 8% (4/48). After operation 46% (20/44) of the patients regained permanent sinus rhythm (20/44 vs 2/48, p < 0.01), supraventricular tachyarrhythmia occurred in 16% of the patients (7/44), 8 patients (18%) had atrial fibrillation, and ventricular preexcitation syndrome was present in 3 patients (7%). The incidence of pacemaker implantation for complete heart block was 11% (5/44). Follow-up was achieved in 95% of patients (40/44) who survived the operation and the perioperative period. The mean follow-up was 63 +/- 54 months (range 4-226 months). During this time there were 6 additional deaths. Eight patients continued to have symptomatic arrhythmias (2 had paroxysmal supraventricular tachycardia, 6 had atrial fibrillation), but 55% of patients (20/36) reported no symptoms of arrhythmia (20/36 vs 2/48, p < 0.01). CONCLUSIONS: Surgical repair improves the quality of life of these patients by reducing the incidence of arrhythmias, in fact less than one sixth of patients continued to have postoperative symptomatic arrhythmias. This can be explained by the interruption of accessory pathways that seem to be a major cause of arrhythmia in Ebstein's anomaly.

Adolescent↗

Coronary reoperations: indications, techniques and operative results. Retrospective study of 240 coronary reoperations.

BACKGROUND: We review twelve-year experience with coronary reoperations so as to better identify indications, techniques and results. METHODS: Between January 1986 and March 1998, 240 coronary reoperations (228 redux, 12 tridux) were performed. There were 223 male and 17 female patients, with a mean age of 63.6+/-7.9 years at the time of reoperation. Mean time interval between operations was 10+/-4.8 years. Symptomatology consisted of: stable recurrent angina (40%), unstable (57%), or congestive heart failure (3%). Pathological feature of the primary grafts was implicated in 95% of cases and atheroma sole progression over native network in 5% of cases. During reoperations 521 (2.2+/-0.8/patient) bypass [venous (40%), arterial (60%)] were performed as well as 15 associated procedures. RESULTS: Operative mortality represented 10% (n=24). Causes of death included infarct (7), left ventricular failure (12), rhythm disorders (2), mediastinitis (1) and multiorgan failure (2). Mortality risk factors were operation date (16.6% before 1992 and 7.4% after, p=0.03), age (13.1% after 60 years old, 2.7% before, p=0.01) time interval between intervention (12% after 8 years, 4% before, p=0.05) and anterograde cardioplegia only (11.8% versus 4.5% when a combined anterograde and retrograde access was used, p=0.06). Morbidity was 31% (71/240). Among the survivors 169 patients (78%) did not experience any complication. CONCLUSIONS: Thanks to a better medico-surgical management, the mortality rate of coronary reoperations is steadily decreasing.

Aged↗

[Left ventricular reconstruction after excision of a large fibroma].

The authors report the case of a 15 year old boy with a large left ventricular fibroma discovered after a series of syncopal episodes due to obstruction to ejection. The first attempt to remove the fibroma in Columbia was only partially successful. In view of the risk of death associated with this type of tumour, it was decided to offer the patient complete excision after a full morphological and functional evaluation of myocardial function and the consequences of the tumour on mitral valve function and on the coronary circulation. The operation was performed under cardiopulmonary bypass and aortic clamping by conventional surgery, associated with reconstruction of the cardiac free wall with a large patch of autologous pericardium which was necessary to avoid cardiac transplantation, the ultimate sanction in this indication.

Adolescent↗

[Staphylococcus epidermidis infective endocarditis after mitral surgery, successfully treated with aspirin and antibiotics: a case report].

We report a case of infectious endocarditis from Staphylococcus epidermidis that occurred early after mitral valve repair (one month), suggested by fever of 38.5 degrees C and valvular vegetations of less than 10 mm on the mitral valve. In the absence of standard recommendations (medical or surgical) in treating patients with infectious endocarditis occurring after mitral valve repair, and in the absence of complications, a medical regimen was chosen associating aspirin (anti-aggregant dosages) with antibiotics. The benefit of aspirin in endocarditis has been demonstrated in experimental studies with regards to valvular vegetations and embolic risk but remains to be studied in human clinical trials. With the association of aspirin (100 mg/d) and triple antibiotic therapy (rifampicin 1200 mg/d, vancomycin 2 g/d, gentamycin 180 mg/d), the clinical status improved with complete regression of vegetations in less than 24 days and the absence of recurrence at one-year follow-up.

Adult↗

Effect of time of day on force variation in a human muscle.

The effect of time of day on the neural activation and contractile properties of the human adductor pollicis muscle was investigated in 13 healthy subjects. Two different times of day were chosen, corresponding to the minimum (7 h) and maximum (18 h) levels of strength. The force produced was compared with the associated electromyographic (EMG) activity during voluntary and electrically induced contractions in order to determine whether peripheral or central mechanisms play a dominant role in diurnal force fluctuation. The results indicated that the force produced during a maximum voluntary contraction (MVC) was significantly higher (+8.9%) in the evening than the morning. Since the increase in force of the MVC and the tetanic contraction (100 Hz) were similar, it is suggested that peripheral mechanisms are responsible for diurnal fluctuations in force. This conclusion is supported by the observation that central activation, tested by the interpolated twitch method during an MVC, did not change, and that the EMG was less per unit force in the evening. In addition to the increase in maximum twitch and tetanus force, significant changes in muscle contractile kinetics were also observed. The maximum rate of tension development and the relaxation of the twitch and tetanus increased in the evening, and the twitch contraction time (CT) and the time to half-relaxation (TR(1/2)) were reduced. Because the mean range of variation in skin temperature (2. 6 degrees C) observed over the course of the day was very low, this change cannot entirely explain those observed in muscle contractile properties.

Adult↗

Single breath exhaled nitric oxide in lung transplant patients: a preliminary clinical study.

Exhaled nitric oxide is considered as a marker of airway inflammation. We report here our preliminary experience with single-breath exhaled nitric oxide measured in lung transplant patients with and without bronchiolitis obliterans syndrome and in cardiac transplant patients. Peak and end-expiratory nitric oxide concentrations did not differ between groups, but single-breath exhaled nitric oxide recordings were strikingly different in patients suffering from bronchiolitis obliterans syndrome, with a slower decrease from peak to end-expiratory nitric oxide concentration. Further studies are required in order to determine whether theses abnormalities reflect the inflammatory process of bronchiolitis obliterans syndrome.

Adult↗

Endoscopic coronary artery bypass grafting with the aid of robotic assisted instruments.

OBJECTIVE: The development of endoscopic coronary artery bypass grafting has been limited because of poor visualization and increased technical difficulties in carrying out operations through ports. We investigated whether the use of robotic assisted instruments could minimize these difficulties. METHODS: After a period of technical development and training on cadavers (n = 8) with the Intuitive Surgical system (Intuitive Surgical, Inc, Mountain View, Calif), the first clinical application in coronary artery surgery was performed in 4 male patients (mean age 59 +/- 6 years) with the indication of grafting the left internal thoracic artery to the left anterior descending coronary artery. Robotic assisted 3-dimensional endoscopes and instruments were introduced into the left side of the chest through 3 intercostal ports. The Heartport system (Heartport, Inc, Redwood City, Calif) was used for arresting the heart during the anastomosis. RESULTS: In 2 patients, the harvesting of the left internal thoracic artery was completed endoscopically with robotic assisted instruments and the anastomosis to the left anterior descending artery was performed through a minithoracotomy with conventional instruments. In 2 other patients, the entire operation was completed endoscopically with robotic assisted instruments. Early postoperative coronary angiography demonstrated the patency of the grafts in all cases. At 6-month follow-up, all patients were free of symptoms. CONCLUSIONS: Robotic assisted instruments make endoscopic coronary bypass possible and open a new era in minimally invasive surgery.

Anastomosis, Surgical↗

Cardiac valve papillary fibroelastoma: surgical excision for revealed or potential embolization.

OBJECTIVE: We have reviewed the case histories of 4 patients who underwent operations between September 1994 and November 1997 at Broussais Hospital for cardiac valvular papillary fibroelastoma. METHODS: Diagnosis was strongly suggested by echocardiography. Tumor locations were mitral (1), tricuspid (1), and aortic (2). Indications for operation were previous stroke for the mitral tumor, prophylaxis for the tricuspid tumor, syncopal episodes for the first aortic tumor, and transient ischemic attack and mesenteric ischemia for the second aortic tumor. RESULTS: Surgical excision with a conservative, valve-sparing approach was performed in all cases. For the first aortic tumor, aortic valve reconstruction was achieved with part of a cryopreserved aortic homograft cusp. Intraoperative transesophageal echocardiography showed no evidence of valvular regurgitation after excision in all cases. All patients had uneventful postoperative recoveries. No evidence of regurgitation or recurrence was seen on echocardiography at follow-up. CONCLUSIONS: Despite their histologically benign aspect, cardiac papillary fibroelastomas should be excised because of potential embolic complications. A conservative, valve-sparing approach is recommended, however, because of the absence of recurrence after total excision.

Adult↗

Load-dependent muscle strategy during plantarflexion in humans.

This study analyses the relative contribution of the triceps surae and tibialis anterior (TA) muscles to tension development with reference to voluntary plantarflexion at two articular positions of the knee joint (extended and flexed at 90 degrees) for various inertial loads. Subjects were instructed to perform plantarflexions at various sub-maximal and maximal velocities with no intention of stopping the movement. Whereas in one series of experiments the subjects were informed of the load countering the movement, in the other they were not. The average electromyographic (EMG) activity of the different muscles was recorded. The main results were that with loading: (a) greater maximal plantarflexion velocities were recorded in flexed as compared to extended-knee positions; (b) greater durations and amplitudes of agonist and antagonist EMG bursts were recorded; (c) the co-activation of the TA and triceps surae muscles was enhanced; (d) unexpected sub-maximal loads induced greater EMG activity and speed of movement. It is concluded that increasing the load during plantarflexion in humans brings about changes in neuromuscular strategies that contribute to the efficiency of contractile activity during rapid movements. The results also indicate that unexpected sub-maximal loading induces a potentiated neuromuscular activity which increases the speed of movement.

Adolescent↗

Mapping of a first locus for autosomal dominant myxomatous mitral-valve prolapse to chromosome 16p11.2-p12.1.

Myxomatous mitral-valve prolapse (MMVP), also called Barlow disease, is a common cardiac abnormality and affects up to 5% of the population. It is characterized by an excess of tissue that leads to billowing of the mitral leaflets, sometimes complicated by prolapse. Typical histological findings include myxomatous degeneration and degradation of collagen and elastin. Previous reports have proposed an autosomal dominant inheritance of the trait, with age- and sex-dependent expression. By systematic echocardiographic screening of the first-degree relatives of 17 patients who underwent mitral-valve repair, we have identified four pedigrees showing such an inheritance. Genomewide linkage analysis of the most informative pedigree (24 individuals, three generations) showed a significant linkage for markers mapping to chromosome 16p, with a two-point maximum LOD score for D16S3068 (Zmax=3.30 at straight theta=0). Linkage to D16S3068 was confirmed in a second family (Zmax=2.02 at straight theta=0) but was excluded for the two remaining families, thus demonstrating the genetic heterogeneity of the disease. Multipoint linkage analysis performed, with nine additional markers, on the two families with linkage gave maximum multipoint LOD scores of 5.45 and 5.68 for D16S3133, according to a conservative and a stringent model, respectively. Haplotype analysis defined a 5-cM minimal MMVP-1 locus between D16S3068 (16p11.2) and D16S420 (16p12. 1) and a 34-cM maximal interval between D16S404 and D16S3068 when recombination events were taken into account only in affected individuals. The identification of this locus represents a first step toward a new molecular classification of mitral-valve prolapse.

Chromosome Mapping↗

Comparison of the acute hemodynamic effects of hypertonic or colloid infusions immediately after mitral valve repair.

OBJECTIVE: To determine the acute hemodynamic effect of hypertonic saline and/or colloid solutions as volume resuscitation in postoperative mitral valve repair patients. DESIGN: Prospective, randomized trial. SETTING: Postoperative cardiac intensive care unit of Broussais Hospital. PATIENTS: Twenty-six patients who underwent mitral valve repair were prospectively studied. Two patients were excluded during the study. INTERVENTIONS: During the immediate postoperative period, when wedge pressure decreases to <8 mm Hg, patients were randomly assigned to receive 250 mL of either hypertonic saline 7.2%-hydroxyethyl starch 6% (molecular weight, 200,000; hydroxyethylation ratio, 0.5) solution (HS-HES group), hypertonic saline 7.2% solution (HS group), or hydroxyethyl starch 6% solution (HES group). The infusion was completed within 15 mins. No additional volume was infused throughout the study. MEASUREMENTS AND MAIN RESULTS: Standard hemodynamic measurements and echocardiographic data demonstrated that HS-HES and HS induced a higher increase in left ventricular end-diastolic area than HES. In the HS-HES and HS groups, systemic vascular resistances decreased significantly and end-systolic area tended to decrease. In the HES group, systemic vascular resistances did not change and end-systolic area tended to increase. Accordingly, ejection fraction increased significantly by 21% and 18% with HS-HES (from 50.5 +/- 5.5 to 61.2 +/- 4.8) and HS (from 49.7 +/- 3.6 to 58.8 +/- 3.3), respectively, and did not change with HES. A major increase in cardiac index was observed after hypertonic solutions infusion, from 2.9 +/- 0.3 to 4.1 +/- 0.4 L/min/m2 in the HS-HES group and from 2.7 +/- 0.3 to 3.8 +/- 0.4 L/min/m2 in the HS group. Then, cardiac index progressively returned to baseline values within the 3 hrs after the infusion. No significant difference was observed between HS-HES and HS. In these groups, plasma sodium increased significantly after the infusion and remained higher than baseline values throughout the study. Adverse events were observed only with hypertonic solution administration: hypotensive episodes, sudden increases in pulmonary capillary wedge pressure, and ventricular arrhythmias. These side effects are likely attributable to a too-high dose and/or rate of infusion. All patients included in the study were discharged from the hospital before the 10th postoperative day. CONCLUSION: We conclude that in patients who have undergone mitral valve repair, postoperative infusion of hypertonic saline solutions increases left ventricular preload and left ventricular ejection fraction. The use of these hypertonic solutions may be of interest in patients with valvular cardiomyopathy. A titrated dose and a low rate of infusion may substantially improve the safety.

Cardiac Surgical Procedures↗