[The role of the urology nurse in prehabilitation and same-day discharge robot-assited radical prostatectomy programs]. / Le rôle de l'IDE dans l'éducation thérapeutique avant opération et la mise en place d'un programme de prostatectomie totale robotique en ambulatoire.

INTRODUCTION: The purpose of this article is to explain the role of urology nurse in prehabilitation and same-day discharge programs for robotic radical prostatectomy. METHODS: This article is based on the analysis of the literature and the experience of our center. RESULTS: In order to prepare patients for outpatient surgery, urology nurse plays a key role during prehabilitation journeys. Two weeks before the operation, the healthcare teams (nurses, anesthetists, physiotherapists, etc.) organize workshops to explain to patients the operation course and post-operative care in order to allay any anxieties. Individual and group interviews, in specific workshops (compression stockings, urinary catheter, sexology) are organized in particular with urology nurse to answer all patients' questions. In association with enhanced recovery after surgery pathway, these programs improve the patient experience and satisfaction as well as peri-operative outcomes, and allows the development of an outpatient surgery program which currently represents approximately one third of surgeries. CONCLUSION: The implementation of perioperative protocols including prehabilitation improves the early results of robotic total prostatectomy, but also the patient experience. The urology nurse has a key role to play during these patient education days and in the preparation, information, support and follow-up of the patient, since the prehabilitation journey until the patient leaves the outpatient clinic.

The third generation Carpentier-Edwards bioprosthesis: early results.

The current status of valve replacement was reviewed by analyzing six groups of 100 consecutive patients, each receiving the standard Carpentier-Edwards bioprosthesis, the Starr-Edwards valve or the Björk-Shiley valve in the mitral or aortic position and operated on by the same surgeons in the same institution during an identical time frame. Data were evaluated for valve failure, reoperation, thromboembolism and valve-related deaths. Long-term results up to 9 years showed the superiority of bioprostheses over mechanical valves in terms of valve-related deaths and thromboembolic and anticoagulant complications for a similar rate of valve failure. Persistent drawbacks associated with valvular bioprostheses, namely, transvalvular gradients, limited durability and tissue calcification in young patients, led to continual improvements in valve design and preservation techniques and the development of the third generation Carpentier-Edwards bioprosthesis: the supraanular porcine valve and pericardial valve. The supraanular porcine valve was designed with the aim of decreasing the transvalvular gradient, decreasing turbulence, increasing longevity and decreasing calcification. The pericardial valve was designed with the aim of improving hemodynamics in small-sized orifices, improving mounting techniques to avoid fixation sutures at the commissures, achieving a flexible stent and improving preservation. Between July 1980 and October 1984, there were 391 supraanular porcine and 61 pericardial valves implanted. The supraanular valves were used for three purposes: isolated aortic, isolated mitral and mitral valve replacement associated with tricuspid anuloplasty. The pericardial valves were used for isolated aortic valve replacement. Short-term results (1 to 4 years) are presented concerning the clinical use of these third generation bioprostheses.

Cellular electrophysiological effects of flecainide on human atrial fibres.

STUDY OBJECTIVE: The aim of the study was to examine the electrophysiological characteristics of human atrial specimens collected during heart surgery and to investigate the effects of the class I antiarrhythmic agent flecainide on their electrical activity. DESIGN: Atrial specimens were studied using standard microelectrode techniques, with and without superfused flecainide (5 x 10(-7) M) or the transient outward current inhibitor 4-aminopyridine (0.5 mM). EXPERIMENTAL MATERIAL: Atrial fragments 0.5-1.0 cm2 were obtained at operation from 34 patients, mean age 30 years. There was no history of previous atrial arrhythmia in any patient and drug therapy was stopped 24 h before surgery. MEASUREMENTS AND MAIN RESULTS: Two types of transmembrane action potential were identified: (1) triangular shaped potentials (group A, classically found in animal models); (2) potentials with a large plateau preceded by a notch (group B). The effect of flecainide was compared on the the two types of action potential. In both, flecainide lessened the depolarisation rate. In group B, but not in group A, it increased the action potential duration at 50% and 90% repolarisation (APD50, APD90) and the effective refractory period. The notch in group B action potentials is generated by transient outward currents (Ito). Inhibition of these currents, either by increasing the pacing rate or by adding 4-aminopyridine, limited the increase in APD50, APD90, and effective refractory period generated by the presence of flecainide. CONCLUSIONS: The effects of flecainide on the atrial repolarisation process depend on the shape of the action potential. These effects are more marked in cells with a plateau, where Ito is activated.

Valve repair with Carpentier techniques. The second decade.

Among 206 consecutive patients having undergone mitral valve repair with a prosthetic ring between 1972 and 1979 in our institution, the 195 patients (94.5%) who survived the operation were studied to assess the long-term function of this method of repair. Patients' ages ranged from 18 to 79 years (mean age 48.7 years). Mitral valve insufficiency was due to degenerative disease in 113 patients (58%), rheumatic disease in 74 (38%), ischemia and other causes in eight patients (4%). A total of 188 patients (9.7%) were in New York Heart Association class III or IV preoperatively and 94 (48%) had atrial fibrillation. The patients were divided into three functional groups: type I (normal leaflet motion), 35 patients (18%); type II (leaflet prolapse), 147 patients (75%); and type III (restricted leaflet motion), 13 patients (7%). The techniques included prosthetic ring annuloplasty (185 patients), leaflet resection (158 patients), chordal shortening (89 patients), leaflet mobilization (10 patients) and papillary muscle reimplantation (2 patients). Long-term follow-up was available in 189 patients (96.8%), for a rate of 2316 patients per year. The 15-year actuarial and valve-related survival rates were 72.4% and 82.8%, respectively. At 15 years, 93.9% of the patients were free from thromboembolism, 96.6% free from endocarditis, 95.6% free from anticoagulant-related hemorrhage, and 87.38% free from reoperation. Actuarial rate of freedom from reoperation was higher in the group with degenerative disease (92.7%) than in the group with rheumatic disease (76.12%). Among the 157 survivors, 117 (74%) were in New York Heart Association class I and class II and 105 (66%) were in sinus rhythm. Doppler echocardiographic studies showed normal ventricular contractility in 134 patients (84.5%), absence of mitral regurgitation in 112 (74%), trivial regurgitation in 27 (17%), and significant regurgitation in 4 patients (2.5%).

Valve extension with glutaraldehyde-preserved autologous pericardium. Results in mitral valve repair.

Preliminary experimental studies in our laboratory have shown that autologous pericardium treated with glutaraldehyde prevents late deterioration and calcification of the tissue. For this reason, glutaraldehyde-treated autologous pericardium has been used in a series of 64 patients who underwent operations for leaflet extension of the mitral valve between 1980 and 1989. Ages ranged from 2.5 to 60 years (mean 19 +/- 15). The causes of mitral valve insufficiency were rheumatic fever (69%), bacterial endocarditis (17%), congenital (8%), endomyocardial fibrosis (4.5%), and trauma (1.5%). The autologous tissue was fixed in a 0.62% glutaraldehyde solution for 15 minutes and rinsed in saline for an additional 15 minutes. Patching techniques varied depending on the site and the extent of the lesion. Associated mitral valve repair techniques (Carpentier's techniques) were mandatory in all patients. The period of follow-up extended from 6 months to 9 years (mean 3.1 +/- 2.5 years). There were no operative deaths in this series, and there was one late death (2%). In the six patients (12%) who underwent reoperation, there has been no case of calcification of the pericardial patch. Postoperative mitral valve function was assessed by bidimensional color Doppler echocardiographic techniques. Mitral valve insufficiency was trivial or absent in 80% of the patients. This experience permits us to conclude that leaflet extension is a simple and safe technique in valve reconstruction, allowing repair of mitral valves that otherwise would need to be replaced. It permits use of an adult-size prosthetic ring in children. Glutaraldehyde-treated autologous pericardium is the material of choice for this type of repair.

Isolated cleft mitral valve: valve reconstruction techniques.

Reports concerning an isolated cleft of the anterior mitral valve are rare. This congenital anomaly of the mitral valve is usually repaired by suturing the edges of the cleft. We report 4 cases of isolated anterior mitral cleft. The patients ranged in age from 13 to 41 years. The clinical symptoms were those typical of mitral insufficiency. In all 4 patients, preoperative echocardiography was able to establish the exact anatomic diagnosis. In 1 patient, the cleft was directly sutured, whereas, in the other 3 patients, a fibrous reaction of the edges of the cleft with a subsequent lack of valvular tissue made direct suture technically impossible. Instead, the fibrous edges of the cleft were resected and the anterior leaflet of the mitral valve was reconstructed using an autologous pericardial patch pretreated with buffered glutaraldehyde. All 4 patients underwent annuloplasty together with placement of a Carpentier mitral ring. Postoperative echocardiograms have confirmed good results of the repair; 1 patient has a trivial insufficiency and 3 have a completely competent mitral valve.

Septal myectomy for left ventricular outflow tract obstruction after mitral valve repair.

We describe a patient with a left ventricular outflow tract obstruction after mitral valve repair. Intraoperative transesophageal echocardiography permitted us to recognize the role of a bulging septum in the development of a systolic motion of the mitral valve. A left ventricular septal myectomy and myotomy was able to relieve the left ventricular outflow tract obstruction and the systolic anterior motion of the mitral valve.

Carpentier "sliding leaflet" technique for repair of the mitral valve: early results.

Reconstructive mitral valve operation is now the preferred technique for the surgical treatment of prolapse of the posterior leaflet due to degenerative disease. Systolic anterior motion of the mitral valve with left ventricular outflow tract obstruction has been observed after such repair, with an incidence ranging from 4.5% to 10%. In an attempt to reduce the incidence of this complication, Carpentier has devised a new technique: the sliding leaflet plasty of the posterior leaflet. We report on 48 patients who underwent this new procedure between July 1990 and July 1992. One patient died perioperatively (2.1%). All other patients were able to be discharged on the ninth postoperative day. All patients underwent M-mode, two-dimensional, and Doppler echocardiography before discharge. Forty-one patients (85%) had no evidence of postoperative regurgitation, whereas 7 patients (15%) showed mild mitral valve insufficiency. Left ventricular outflow tract obstruction due to systolic anterior motion of the mitral valve was never detected. We believe that this technique of mitral valve repair is safe and seems to be effective in achieving a decreased incidence of left ventricular outflow tract obstruction.

Mitral valve repair in the extensively calcified mitral valve annulus.

Mitral valve replacement in patients with an extensively calcified mitral annulus is associated with an increased risk of ventricular rupture. Until now techniques of mitral valve repair have not been applied to patients with a heavily calcified mitral valve annulus. We present 12 patients who underwent extensive decalcification of the annulus with subsequent mitral valve repair between 1987 and 1990. Ages ranged from 11 to 78 years; 6 patients were in New York Heart Association functional class II, 4 were in class III, and 2 were in class IV. All patients had varying degrees of mitral insufficiency. There were no deaths, reoperations, or thromboembolic events. Postoperative echocardiography revealed minimal residual mitral insufficiency in only 2 of 12 patients. All patients are currently in New York Heart Association class I or II. We believe mitral valve repair can be done safely on patients with an extensively calcified mitral annulus, thus avoiding the risks of left ventricular rupture, thromboembolic events, and hemorrhagic complications associated with mitral valve replacement.

Valve repair for mitral regurgitation caused by isolated prolapse of the posterior leaflet.

BACKGROUND: Although prolapse of the posterior leaflet is the most common abnormality of the mitral valve causing dysfunction, the long-term results of mitral valve repair for this condition are seldom reported. METHODS: From October 1988 to June 1994, 208 patients (mean age, 59.4 years) with mitral regurgitation caused by isolated prolapse of the posterior leaflet underwent mitral valve repair alone or combined with myocardial revascularization (n = 30). The surgical techniques were quadrangular resection (n = 199) followed by annulus plication (n = 101) or sliding leaflet plasty (n = 98), use of artificial chordae (n = 5), or papillary muscle shortening (n = 4). All patients had an annuloplasty with a Carpentier ring. Mean follow-up was 3.4 +/- 0.1 years and total follow-up, 656 patient-years. RESULTS: There were six operative deaths (2.9%). Postoperative Doppler echocardiography found two cases of systolic anterior motion (1%), and echocardiographic studies at follow-up showed satisfactory mitral valve function in 97% of 112 patients. At 6 years, the actuarial survival rate was 87% +/- 7%, and freedom from thromboembolic complications, bleeding complications, and reoperation was 93% +/- 7%, 95% +/- 3%, and 95% +/- 4%, respectively. CONCLUSIONS: Mitral valve repair for regurgitation caused by prolapse of the posterior leaflet provides excellent survival at 6 years and should be considered the method of choice for its surgical treatment.

A 10-year comparison of mitral valve replacement with Carpentier-Edwards and Hancock porcine bioprostheses.

Two hundred fifty-three patients who underwent isolated mitral valve replacement with a porcine bioprosthesis had long-term evaluation. One hundred forty-seven patients received a Carpentier-Edwards porcine bioprosthesis and 106, a Hancock valve. There were no significant differences in preoperative clinical characteristics between the two groups. Cumulative follow-up was 1,375 patient-years. At 10 years, 93% +/- 2.5% of the patients in the Carpentier-Edwards group and 85% +/- 7.8% of those in the Hancock group were free from valve-related death (not significant), and 95% +/- 2% and 91% +/- 3.8%, respectively, were free from thromboembolism (not significant). At 10 years, 65% +/- 7.2% of the patients in the Carpentier-Edwards group and 66% +/- 7.2% of those in the Hancock group were free from structural valve deterioration (not significant), and 64% +/- 6% and 59% +/- 7.3%, respectively, were free from reoperation (not significant). We conclude that the first generation of Carpentier-Edwards and Hancock prostheses produce comparable long-term results in the mitral position.

Reversibility of muscular ischemia: a histochemical quantification by the nitroblue tetrazolium (NBT) test.

The degree of muscular ischemia and its reversibility can be quantified in the early stages. This histochemical enzymatic study utilized Nitroblue tetrazolium (NBT) which when reduced by tissue dehydrogenase produces a blue pigment: "formazan." Seventy Wistar rats were subjected to transient hindlimb ischemia by means of a tourniquet for 3, 6, 9, 12, 15 and 18 hours, followed by reperfusion. Microsurgical muscle biopsies were obtained in each rat at 1 and 12 hours, and 3, 7, 14 days after reperfusion. Time increased in muscle staining demonstrated a succino-dehydrogenase deficit confirmed by clinical and histopathological follow-up. NBT staining time was 2 minutes (+/- 8 sec.) in the control group, between 2 and 6 minutes in the reversible ischemia group (rats with 3 and 6 hours of tourniquet), and more than 9 minutes (+/- 14 sec.) in the irreversible ischemia group (animals with more than 9 hours of tourniquet). In vascular surgery and in limb reimplantation this protocol is a practical method of evaluating cytoplasmic enzymatic activity and the status of myofibrillar oxidation in the early phases of ischemic injury, before histologic changes are clearly delineated.

Dynamic cardiomyoplasty: a surgical approach for ventricular assistance.

Dynamic cardiomyoplasty involves the use of an electrically stimulated skeletal muscle wrapped around part of the heart to restore or augment myocardial contractility. In our approach, a Latissimus Dorsi muscle flap (LDMF) is transferred to the heart via a partial resection of the second rib, and sutured around the ventricles. The muscle flap is stimulated in synchrony with the heart contractions with bursts of impulses delivered by a "Cardio-Myostimulator" implantable pulse generator via intramuscular electrodes. The object of this study was to identify features of muscle stimulation and to measure the efficacy of L.D. cardiomyoplasty in increasing cardiac output, using an ultrasonic Doppler technique. This report shows the results obtained for goats in which such procedures were performed. Ultrasonic measurements were recorded at the time of cardiomyoplasty and 3-6 months later, during which period the muscle was put progressively into use by slowly increasing the burst frequency content, number of pulses as well as the heart-muscle contraction ratio (3:1, 2:1, 1:1). This postoperative muscle stimulation protocol takes into account the delay of gradual conversion of fast-twitch glycolytic muscular fibers into slow-twitch oxidative, fatigue-resistant fibers, as well as the healing time after cardiomyoplasty required for the muscle flap to recover collateral blood circulation and to adhere to the heart. Results show that synchronous burst stimulation of the muscle flap increases the blood peak velocity in the descending aorta (+36 +/- 8%) and increases the left ventricular stroke volume (+70 +/- 14%).(ABSTRACT TRUNCATED AT 250 WORDS)

[Isolated prolapse of the posterior leaflet of the mitral valve. Results of reconstructive surgery]. / Prolapsus isolé du feuillet postérieur de la valve mitrale. Résultats de la chirurgie reconstructrice.

Out of 522 patients undergoing mitral valve reconstruction for mitral regurgitation between 1988 and June 1994, the authors studied 159 cases of isolated mitral regurgitation by prolapse of the posterior mitral leaflet. There were 98 men (62%) and 61 women (38%), with an average age of 58.4 +/- 10.4 years. The functional class and ejection fraction were 2.8 +/- 0.11 and 0.66 +/- 0.2 respectively. In 155 patients, surgery consisted in quadrangular resection of the prolapsed tissue, followed in 83 cases by sliding posterior valvuloplasty and in 72 cases by plicature of the annulus. In 4 cases, the prolapse was treated by implantation of artificial chordae tendinae. A Carpentier-Edwards ring was inserted in all cases. There were no hospital deaths. Echocardiography was performed before discharge from hospital and showed satisfactory mitral valve function in 98% of cases: slight systolic anterior motion (SAM) was observed in one case. All patients were followed up for an average of 3.67 +/- 0.10 years. At six years, survival was 93 +/- 7%; moreover, 93 +/- 7% and 97 +/- 3% of patients had no thromboembolic or haemorrhagic complications. Six patients were reoperated, three of them in the first year of follow-up. At six years, 95 +/- 5% of patients were free of reoperation and 81 +/- 11% were free of all complications. The authors conclude that the excellent medium term survival and the low rate of complications are evidence in favour of conservative surgery for treatment of mitral regurgitation due to prolapse of the posterior mitral leaflet.

[Recurrent myocardial abscess during Streptococcus B endocarditis]. / Abcès myocardique récidivant au cours d'une endocardite à streptocoque B.

The authors report a case of serious streptococcus B endocarditis with a myocardial abscess that recurred after surgery. Streptococcus B endocarditis is a rare disease which is characterized by a pronounced tropism of the organism for cardiac tissues, with severe cardiac valve mutilation and abscess formation in 40% of the cases. A myocardial abscess makes the prognosis worse and must be treated surgically during the acute phase of endocarditis. Modern imaging methods, notably trans-oesophageal two-dimensional echocardiography and computerized tomography should now be used to detect such abscesses.

[Myocardial protection during ischemic cardiac arrest. Hemodynamic study of the effects of allopurinol in a cardioplegic solution]. / Protection myocardique pendant l'arrêt cardique ischémique. Etude hémodynamique des effets de l'allopurinol dans un soluté cardioplégique.

The effects of the addition of 20 mg sodium allopurinate to a litre of ionic cardioplegic solution were studied. The experimental model was the working isolated perfused rat heart in oxygenated Krebs-Henseleit solution. The cardiac outputs were compared after 1 hour of ischaemia with three different methods of myocardial protection; group I: protection by hypothermia at 4 degrees C, group II: protection by ionic cardioplegic solution A, group III: by ionic cardioplegic solution B (with 20 mg Allopurinol). The results were expressed in percentage of the preischemic cardiac output. The best results were obtained in group III, especially after 15 minutes recovery (80.7 +/- 4.5 p. 100 at 15 minutes, 90.6 +/- 3.1 p. 100 at 30 minutes., 88.3 +/- 4.6 p. 100 at 1 hour). The results in group II were significantly better than in group I after 10 minutes recovery. Myocardial protection bu ionic cardioplegia associated with hypothermia at 4 degrees C gives a better post ischaemic recovery than hypothermia alone. When allopurinol is added to the cardioplegic solution, the protection is increased. These effects are similar to the haemodynamic effects of allopurinol on ischaemic myocardium together with the possible limitation of experimental myocardial infarction with regression of the oedema that has been observed with this drug.

[Valvuloplasties for acquired mitral insufficiency in children (Carpentier's technic). Long-term results in 87 cases]. / Valvuloplasties pour insuffisance mitrale acquise de l'enfant (technique de Carpentier). Résultats à long terme de 87 cas.

Between March, 1969 and March, 1984, 89 children aged from 2 to 12 years (mean: 8.3 +/- 2.5 years) and presenting with mitral valve regurgitation underwent valvuloplasty by the Carpentier technique. The cause of the regurgitation was rheumatic fever in 84 cases (94 p. 100), bacterial endocarditis in 4 cases and Barlow's disease in 1 case. Mitral valve regurgitation was divided into 3 types, namely: type I, normal valve motion (5 cases), type II, valve prolapse (74 cases) and type III, restricted valve motion due to fibrosis of the leaflets or chordae (20 cases). The hospital mortality rate was 2.3 p. 100 (2 deaths). The cumulative follow-up was 546 patients/years, and the actuarial survival rate at 10 years was 89.96 +/- 8.5 p. 100. At 10 years the actuarial thromboembolic complication rate was 2 p. 100, or 0.3 +/- 0.2 p. 100 per patient year, and the actuarial valvuloplasty deterioration rate was 27 +/- 8.5 p. 100. The risk of re-operation was 2.2 +/- 0.6 p. 100 per patient year. At 10 years 78.4 +/- 7.2 p. 100 of the children were free of all re-operation, and 69 p. 100 had no complication. Thus, whenever possible (i.e. in 90 p. 100 of the cases, according to our experience) and considering the satisfactory long-term results, all children with acquired mitral valve regurgitation should undergo mitral valvuloplasty as first-line treatment.

[Cardiomyoplasty. Experimental bases, operative technic, indications]. / Cardiomyoplastie. Bases expérimentales, technique opératoire, indications.

Dynamic cardiomyoplasty aims at restoring ventricular contractility by means of a skeletal muscle sutured around the heart. It consists of transferring a latissimus dorsi muscle flap onto the heart through a window created in the thoracic wall by partial resection of the second rib. The skeletal muscle may be used to reinforce the ventricular systole in ischemic or dilated cardiomyopathy, or to replace the myocardium after resection of a large aneurysm or an extensive tumour. The electronic pacing material includes an implantable cardiomyostimulator, muscle stimulating electrodes and R wave detecting electrodes. Muscular pacing begins 2 weeks after the operation, this being the time required for adhesions to be formed between the heart and the muscle. A progressive and sequential electrostimulation procedure results in the transformation of glycolytic muscle fibres that are fatigue-sensitive into fatigue-resistant oxidative fibres. The purpose of this biomechanical cardiac assistance system, where cardiac surgery is combined with plastic surgery and biomedical engineering, is to prolong life and improve its quality in patients with severe heart failure.

[Comparative evaluation of various methods of treatment of mitral valve diseases. Apropos of 4 series of 100 patients operated on using the Starr prosthesis, Bjork prosthesis, bioprosthesis and valve reconstruction]. / Evaluation comparative de différentes méthodes de traitement des valvulopathies mitrales. A propos de quatre séries de 100 malades opérés par prothèse de Starr, prothèse de Björk, bioprothèse et reconstruction valvulaire.

The results of 4 groups of 100 patients undergoing mitral valvuloplasty (group I), isolated mitral valve replacement by a bioprosthesis (group II), a Starr-Edwards prosthesis (group III) and a Björk prosthesis (group IV) between 1974 and 1977 were compared. The selection of patients for each group was identical and made according to strict criteria. The average age was between 47.1 +/- 12.5 years and 51.8 +/- 10.5 years according to the particular group; the average functional classification was 2.4 +/- 0.4 to 2.5 +/- 0.6; the average cardiothoracic ratio was 0.58 +/- 0.07. Most patients were in atrial fibrillation. Ninety-seven per cent of patients were followed-up by questionnaires. The results were expressed with respect to simple clinical events used in all previously reported series. The long-term mortality was identical in the 3 groups undergoing valve replacement (40 p. 100 at 7 years) but was much less in the group undergoing valvuloplasty (18 p. 100 at 7 years). The mortality rate due to valvular problems was significantly less in the valvuloplasty group (2 p. 100 at 7 years) than in the groups with mechanical prostheses (20 p. 100 at 7 years). Intermediate results were observed in the bioprosthetic group (9 p. 100 at 7 years). Thrombo-embolism was significantly less common in the groups undergoing valvuloplasty and bioprosthetic valve replacement (2 p. 100 and 6 p. 100 at 7 years) than in the group with Starr-Edwards and Björk prostheses (30 p. 100 and 32 p. 100 at 7 years).(ABSTRACT TRUNCATED AT 250 WORDS)

[Demonstration of abnormalities of myocardial mitochondrial oxygenation in cardiac graft rejection]. / Mise en évidence d'anomalies de l'oxydation mitochondriale myocardique au cours du rejet de greffe cardiaque.

Abnormalities of myocardial metabolism during acute rejection may be due to ischemia to primary metabolic changes related to rejection. An experimental study of heterotopic cardiac transplantation in the rat was undertaken to study myocardial mitochondrial oxidation during acute rejection. The receivers were Lewis rats and the donors Fischer (FL: allograft) or Lewis (LL: isograft) rats. The oxygen consumption of the mitochondria (VO2m) isolated from the transplanted and native hearts was measured by oxygraphy six days after transplantation. Using maleate and glutamate substrates, the VO2m of transplanted hearts was significantly lower than that of native hearts in the two groups of rats (FL, p less than 0.01; LL, p less than 0.01). In addition, the VO2m of FL allograft transplanted hearts was significantly lower than in the LL rats (30 +/- 9 vs 100 +/- 15 nanoatoms of oxygen/min.mg/prot, p less than 0.01) as was the VO2m of the native hearts (FL: 106 +/- 23 vs LL: 164 +/- 26, p less than 0.02). The respiratory control ratio (RCR) was significantly lower in the transplanted than in the native hearts in both the FL and LL groups (p less than 0.05 and p less than 0.01 respectively). The comparison of the RCR in the two groups (FL vs LL) showed no significant difference for transplanted or native hearts. Electron microscopy of transplanted (rejected or not) and native hearts showed no morphological abnormality of the mitochondria. The lower VO2m of the allograft group indicates a disturbance in the mitochondrial respiratory pathway during acute rejection.(ABSTRACT TRUNCATED AT 250 WORDS)