PubMed Health⌕ Search

Biomedical subjects

Alain Carpentier

Publications and source records attributed to Alain Carpentier.

11 recordsLinked to original sources
PubMed2002

Reflex regulation during sustained and intermittent submaximal contractions in humans.

To investigate whether the intensity and duration of a sustained contraction influences reflex regulation, we compared sustained fatiguing contractions at 25 % and 50 % of maximal voluntary contraction (MVC) force in the human abductor pollicis brevis (APB) muscle. Because the activation of motoneurones during fatigue may be reflexively controlled by the metabolic status of the muscle, we also compared reflex activities during sustained and intermittent (6 s contraction, 4 s rest) contractions at 25 % MVC for an identical duration. The short-latency Hoffmann(H) reflex and the long-latency reflex (LLR) were recorded during voluntary contractions, before, during and after the fatigue tests, with each response normalised to the compound muscle action potential (M-wave). The results showed that fatigue during sustained contractions was inversely related to the intensity, and hence the duration, of the effort. The MVC force and associated surface electromyogram (EMG) declined by 26.2 % and 35.2 %, respectively, after the sustained contraction at 50 % MVC, and by 34.2 % and 44.2 % after the sustained contraction at 25 % MVC. Although the average EMG increased progressively with time during the two sustained fatiguing contractions, the amplitudes of the H and LLR reflexes decreased significantly. Combined with previous data (Duchateau & Hainaut, 1993), the results show that the effect on the H reflex is independent of the intensity of the sustained contraction, whereas the decline in the LLR is closely related to the duration of the contraction. Because there were no changes in the intermittent test at 25 % MVC, the results indicate that the net excitatory spinal and supraspinal reflex-mediated input to the motoneurone pool is reduced. This decline in excitation to the motoneurones, however, can be temporarily compensated by an enhancement of the central drive.

Action Potentials↗
PubMed2002

Frequency, predictors, and consequences of atrioventricular block after mitral valve repair.

This study examines the incidence, predictors, and evolution of postoperative atrioventricular block (AVB) after mitral valve repair (MVR) in 115 consecutive patients using Carpentier's technique (between November 1996 and April 1997). Postoperative AVB occurred in 27 patients (23%). Third-degree AVB was found in 7 patients (6%) in the immediate postoperative period, but in 4 it was transient, resolving partially or completely before the seventh postoperative day. Second-degree AVB (Mobitz type I) occurred in 4 patients (3%) immediately after operation and resolved in all before hospital discharge. Isolated first-degree AVB occurred in 16 patients (14%) and was permanent in 12. Neither the preoperative variables nor the mitral procedures including anterior versus posterior leaflet repair were related to postoperative AVB. A lesser systemic hypothermia during surgery was the only, modestly independent predictor of postoperative AVB (odds ratio 1.53; 95% confidence interval 1.04 to 2.25; p = 0.031). Three patients (2.6%) had permanent pacemaker implantation, on average 18 days after operation, and all had persistent third-degree AVB. With a mean follow-up of 3 years, no recurrence or worsening of conduction disturbances, no further pacemaker implantation, and no late deaths were observed.

Adolescent↗
PubMed2002

Human leukocyte antigen-G expression after heart transplantation is associated with a reduced incidence of rejection.

BACKGROUND: Human leukocyte antigen (HLA)-G, a nonclassic major histocompatibility complex class I molecule expressed in the extravillous cytotrophoblast at the feto-maternal interface, is known to protect the fetus from maternal cellular immunity. In a preliminary study, we showed that HLA-G is expressed in the hearts of some patients after heart transplantation. METHODS AND RESULTS: In the present study, a larger number of patients was investigated to confirm this finding and to look for possible correlations between HLA-G expression and the number and types of rejection. Expression of HLA-G in endomyocardial biopsy specimens was investigated by immunohistochemical analysis, and detection of the soluble HLA-G in the serum was performed by immunoprecipitation followed by Western blot analysis. HLA-G was detected in the biopsy specimens and serum of 9 of 51 patients (18%). The number of episodes of acute rejection was significantly lower in HLA-G-positive patients (1.2+/-1.1) as compared with HLA-G-negative patients (4.5+/-2.8) (P<0.001). No chronic rejection was observed in HLA-G-positive patients, whereas 15 HLA-G-negative patients had chronic rejection (P<0.032). A longitudinal study of these patients reveals that the status of HLA-G expression was maintained after 6 months both in serum and in biopsy specimens. During this period, HLA-G-positive patients did not have chronic rejection. CONCLUSIONS: There is a significant correlation between rejection and HLA-G expression in the heart after transplantation. HLA-G expression and its effect in reducing the incidence and severity of rejection seem to be stable throughout the evolution.

Adult↗
PubMed2002

Triple valve repair for young rheumatic patients.

BACKGROUND: Facing young foreign polyvalvular rheumatic patients, for which long-term anticoagulation is not available, we have chosen to attempt triple valve repair procedures in order to avoid prosthetic implantation in this particular population suffering from triple valve disease. METHODS: Twenty-one young rheumatic patients (mean age:11+/-4 years) underwent triple valve repair procedures including cusp extension on the aortic valve aortic between September, 1992 and December, 2000. Valvular pathology characteristics according to Carpentier's classification included mitral insufficiency type III post+II ant (n=10), type III post (n=4), type II ant (n=2), mitral stenosis (n=5), type III aortic insufficiency (n=21), type I (n=13) and type III (n=8) tricuspid insufficiency. RESULTS: Firstly, the mitral valve disease were corrected using Carpentier's techniques of repair: prosthetic ring annuloplasty (n=16), commissurotomy (n=12), chord transposition (n=11) or shortening (n=4), papillary muscle sliding plasty (n=4) and pericardial patch leaflet enlargement (n=6). Secondly, aortic lesions were corrected using glutaraldehyde stabilized autologous pericardium triple cusps extension technique (n=21). Lastly, tricuspid repairs were always performed on beating hearts using commissurotomy (n=8), prosthetic ring (n=12) or other techniques (n=9) of annuloplasty. The operative mortality was 4.7% (one patient died). Echocardiograms before discharge showed grade I mitral insufficiency in seven patients and grade I aortic insufficiency in five patients. There was no late death during a mean follow-up of 51+/-31 months. Two patients underwent valvular redo surgery because of aortic and mitral plasty deterioration due to rheumatic disease progress. After 5 years, 90% of the patients were free from redo valvular surgery. CONCLUSIONS: In rheumatic patients, autologous pericardial patch extension of the aortic valve permitted widespread use of reconstructive surgery even in patients suffering from triple valve disease. Triple valve repair, in this particular challenging setting of patients, has provided satisfactory initial and mid-term results and could be considered as an interesting palliative surgical approach.

Child↗
PubMed2002

[Planning and simulation of minimally-invasive robotic heart surgery].

Due to their numerous advantages, mainly in terms of patient benefit, mini-invasive robotically assisted interventions are gaining in importance in various surgical fields. However, this conversion has its own challenges that stem from both its novelty and complexity. In this paper we propose to accompany the surgeons in their transition, by offering an integrated environment that enables them to make better use of this new technology. The proposed system is patient-dependent, and enables the planning, validation, simulation, teaching and archiving of robotically assisted interventions. The approach is illustrated for a coronary bypass graft using the daVinci tele-operated robot.

Cardiac Surgical Procedures↗
PubMed2002

Robotic-assisted cardiac surgery: anesthetic and postoperative considerations.

OBJECTIVE: To assess the feasibility of endoscopic telemanipulated cardiac surgery and describe the anesthetic, postoperative, and surgical implications of minimally invasive robotic-assisted cardiac surgery. DESIGN: Prospective study. SETTING: Cardiovascular and transplant center, university hospital. PARTICIPANTS: Twenty patients (13 men, 7 women) scheduled for either coronary artery bypass graft surgery or valve surgery. Mean age was 53 +/- 5 years (range, 31 to 75 years) and mean New York Heart Association class was 2.4. Three patients (6 %) were having redo procedures, and 1 patient had bacterial endocarditis. INTERVENTIONS: Surgery was done with the aid of the daVinci surgical robot (Intuitive Surgical, Mountain View, CA). Induction and maintenance of anesthesia consisted of a target-controlled infusion of remifentanil and propofol. In 11 cases (55%), cardiopulmonary bypass was performed with Port-Access technology (Heartport, Redwood City, CA), and in the remaining 9 cases (45%), conventional femorofemoral bypass was used. MEASUREMENTS AND MAIN RESULTS: Fifteen patients (75 %) were extubated within 6 hours and discharged from the cardiac surgery intensive care unit on postoperative day 1. Two patients (10%) were reexplored in the immediate postoperative period. Two conversions to thoracotomy were reported. One reoperation at 6 months and 1 late death occurred. At 1-year follow-up, excellent functional results were observed in 18 cases. CONCLUSION: Caution should be used when assessing innovative medical-surgical techniques. Despite technical difficulties and lengthy procedures, results were satisfactory. The feasibility of robotic-assisted surgery for coronary artery bypass graft and valve procedures is intuitively appealing.

Adult↗
PubMed2002

Exhaled nitric oxide does not reflect the severity of acute lung injury: an experimental study in a rat model of extracorporeal circulation.

OBJECTIVE: This study was undertaken to determine whether an increase in exhaled nitric oxide would reflect the severity of the acute lung injury caused by extracorporeal circulation. DESIGN: Prospective, controlled animal laboratory investigation. SETTING: University laboratory. SUBJECTS: Male, anesthetized, paralyzed, and mechanically ventilated Wistar rats (n = 34). INTERVENTIONS: Twenty-three Wistar rats underwent a partial (100 mL.kg(-1).min(-1)) femoro-femoral extracorporeal circulation in normothermia for 90 mins. Eleven time-matched rats formed the sham group. MEASUREMENTS AND MAIN RESULTS: Exhaled nitric oxide was monitored with a chemiluminescence analyzer. Acute lung injury was assessed by blood gas analysis and lung water content. Lung Evans blue dye content, lung myeloperoxidase, and heme oxygenase activities were determined. Compared with the sham rats, extracorporeal circulation was responsible for acute lung injury characterized by an increased lung water content (82.4 +/- 1.3% vs. 77.9 +/- 1.1%; p<.05), an increased Evans blue dye content (191.8 +/- 15.8 vs. 112.5 +/- 16.8 mg/g tissue wet weight; <.01), and an increased pulmonary heme oxygenase activity (332.9 +/- 107 vs. 113.7 +/- 46.5 pmol. hr(-1).mg of protein(-1); p<.05). Exhaled nitric oxide remained stable throughout the experiment in all sham rats. Among the 23 rats that underwent extracorporeal circulation, eight rats (35%) experienced an increase in exhaled nitric oxide concentration (16.9 +/- 12.7 ppb). There was no significant difference between rats that did or did not experience an increase in exhaled nitric oxide regarding each index of acute lung injury. CONCLUSIONS: An increase in exhaled nitric oxide did not reflect the severity of the acute lung injury caused by extracorporeal circulation. Its significance remains to be determined.

Animals↗
PubMed1999

Mitral valve repair in children using Carpentier's techniques.

Controversy remains regarding whether valve repair is preferable to valve replacement in children suffering from rheumatic mitral valve disease. To answer this question, 130 children aged 3 to 15 years (mean age, 11.8 +/- 2.8 years) undergoing surgery between January 1992 and December 1997 using Carpentier's techniques were reviewed. There were 111 cases of rheumatic valve diseases (85%), 17 cases of congenital mitral valve malformations (13%), one case of Barlow's syndrome (1%), and one case of bacterial endocarditis (1%). Valve dysfunction was classified into three types according to Carpentier's classification. There were 14 type II (leaflet prolapse), 78 type III (restricted leaflet motion), and 38 associated type II (anterior leaflet) and III (posterior leaflet) cases. There was one early (in-hospital) death (0.7%); the remaining 129 children were examined every 6 months. At the last examination, 99.2% of the patients were still alive, 96.8% were free of reoperation, and 89% showed no sign of significant residual stenosis or insufficiency on echocardiography. There have been no thromboembolisms. We conclude that mitral valve repair using Carpentier's techniques is the preferred procedure in the surgical treatment of mitral valve incompetence in children, even in those with rheumatic valvular disease. Copyright 1999 by W.B. Saunders Company

Journal Article↗