Régine Roussin

Implication of Double-Stranded RNA Signaling in the Etiology of Autoimmune Myasthenia Gravis

Myasthenia gravis (MG) is an autoimmune disease mediated mainly by anti–acetylcholine receptor (AChR) antibodies. The thymus plays a primary role in MG pathogenesis. As we recently showed an inflammatory and antiviral signature in MG thymuses, we investigated whether pathogen‐sensing molecules could contribute to an anti‐AChR response.

Systemic obstruction in univentricular hearts: surgical options for neonates.

BACKGROUND The surgical management for bridging patients with univentricular heart and systemic obstruction to a Fontan procedure remains controversial. METHODS Twenty-seven of 96 patients with univentricular heart and unobstructed pulmonary blood flow referred for surgical palliation were seen with systemic obstruction. Twenty-six were neonates with coarctation of the aorta in 21 and subaortic stenosis in 5. In 8 other patients, subaortic stenosis developed after initial pulmonary artery banding. Four different palliative procedures were performed: coarctation repair with pulmonary artery banding (group I, n = 15); Norwood or Damus-Kaye-Stansel or arterial switch operation (group II, n = 9); coarctation repair with pulmonary artery banding and bulboventricular foramen enlargement (group III, n = 2); and orthotopic heart transplantation with coarctation repair (group IV, n = 1). RESULTS The mortality rate was 34.3% (n = 12) for all patients, 53.3% in group I, 33.3% in group II (p = 0.003 versus group I), and 50% in group III. Nine patients (8 in group I and 1 in group II) had development of subaortic stenosis and underwent a subsequent procedure: Damus-Kaye-Stansel operation in 5, arterial switch operation in 3, and bulboventricular foramen enlargement in 1. Three had a concomitant or subsequent Fontan procedure and 2, a bidirectional Glenn procedure. In group II, 1 patient underwent a subsequent Fontan procedure and another, a bidirectional Glenn anastomosis. Six of the 8 patients with subaortic stenosis after initial pulmonary artery banding underwent a second stage consisting of a Damus-Kaye-Stansel procedure (n = 3), bulboventricular foramen enlargement (n = 2), or creation of an aortopulmonary window (n = 1). Three had a concomitant Fontan procedure and 2, a bidirectional Glenn procedure. Actuarial 4-year survival was 65.5% +/- 8.4% (70% confidence limits) for all patients; it was 40% +/- 13.3% in group I and 66.6% +/- 16.3% in group II (p < 0.05). CONCLUSIONS Initial management of patients with univentricular heart and systemic obstruction by Norwood-like procedures provides a better outcome. Success of the Fontan operation relies on the ability to provide timely relief of subaortic stenosis.

The Performance of Hancock Porcine-Valved Dacron Conduit for Right Ventricular Outflow Tract Reconstruction

BACKGROUND The surgical reconstruction of right ventricle outflow tract (RVOT) often requires the implantation of a valved conduit. Homografts are lacking availability and are associated with limited durability in children. Our experience with the Hancock porcine-valved Dacron (DuPont, Wilmington, DE) conduit (Medtronic, Minneapolis, MN) was retrospectively assessed. METHODS Follow-up was studied in 214 survivors who underwent 247 conduit implants between January 1990 and January 2007. Pulmonary atresia/ventricular septal defect was present in 86 (40.2%) and truncus arteriosus in 62 (29%). Conduit implantation was associated with anatomic repair in 136, conduit replacement in 96, and secondary pulmonary valve insertion in 15. Median age at operation was 62.5 months (range, 1 week to 50 years), including 14 neonates (6%). Median conduit size was 17.4 mm because of routine over-sizing. Pulmonary bifurcation patch augmentation was necessary in 26 patients. Periodic echocardiography studies were performed for a median follow-up of 98 months (range, 13 to 142 months). RESULTS Three (1.4%) late deaths occurred. No conduit-related deaths or complications occurred. Conduit degeneration was associated with increase in valvular gradient. Valve regurgitation was absent or mild. Higher RVOT systolic pressure gradient at discharge did not influence conduit longevity. Conduit reoperation was delayed due to percutaneous balloon dilatation in 14 patients, associated with stenting in 7. Survival with freedom from conduit reoperation was 98% (95% confidence interval [CI], 97% to 100%) at 1 year, 81% (95% CI, 75% to 87%) at 5 years, and 32% (95% CI, 22% to 42%) at 10 years. CONCLUSIONS The Hancock valved conduit is a safe and reliable alternative to homografts. It appears to be appropriate in patients with limited pulmonary vascular bed and high pulmonary artery pressures. Caution is required in neonates because of the rigidity of the Dacron housing. Initial results with secondary percutaneous procedures are encouraging.

Surgical management of congenital heart defects associated with heterotaxy syndrome

OBJECTIVE Heterotaxy syndrome (HS) is generally associated with complex congenital cardiac defects and has a high morbidity and mortality despite recent surgical progress. Only few reports deal with an overall surgical population. METHODS Between 1989 and 2008, 139 patients with HS entered a programme of surgical repair. Fifty-one patients were suitable for univentricular heart repair (UVR) and 88 for biventricular repair (BVR). Among those tracked for UVR, two were switched to BVR and 11 from BVR to UVR. Median age at first surgery was 4.4 months (range: 3 days to 43 years] of whom 34 were neonates. The mean number of surgical procedure per patient was 1.99. Primary BVR was performed in 37 patients. Re-operation was required in 22 patients, 15 after BVR and seven after UVR (p>0.05). RESULTS The overall mortality was 20.8%. It was 7.2% after the first surgery, 6.6% after the second and 11.5% after the third. The overall mortality in patients with univentricular physiology was 25.5% and 18.2% in the biventricular group (p<0.05). According to the surgical track, in the UVR group, mortality was 18% and 15.6% in the BVR group (p=NS). This rate was 40% in patients with long-lasting palliation (p<0.05 vs both other groups). Median follow-up was 127 months (range: 1 month to 19 years). The overall survival rate at 15 years was 70.6%. When considering ventricular anatomy, survival rates at 15 years were 69% for the univentricular group and 74.2% for the biventricular group (p>0.05). According to the type of surgical approach, at 15 years they were 85.1% for UVR and 77% for BVR (p=NS). For the palliation group, it was 15% only at 15 years (p<0.05 vs both other groups). Risk factors for overall mortality were neonatal surgery, long-standing palliation, total anomalous pulmonary vein return (TAPVR) and right ventricular outflow tract obstruction (RVOTO). At the last visit, all survivors were in the New York Heart Association (NYHA) class I to II and only two presented with supraventricular arrhythmias. CONCLUSIONS HS remains a difficult situation with high morbidity and mortality. An aggressive approach to repair TAPVR when present should be considered. Early decision to track the patient in either uni- or biventricular repair programme should avoid long-lasting deleterious palliation.

Aortic valve replacement in the elderly: bioprosthesis or mechanical valve?

BACKGROUND With increased life expectancy, valve operations are more and more common in elderly patients. The choice of valve substitute-mechanical valve or bioprosthesis-remains debated. METHODS Two groups of patients of the same age (69, 70, and 71 years) with isolated aortic valve replacement (mechanical 240, bioprostheses 289) were compared for mortality, morbidity, and valve-related complications. RESULTS No significant difference was found in survival, valve-related mortality, valve endocarditis, and thromboembolism. Mechanical valve had more bleeding events; bioprostheses had more structural deterioration, reoperation, and valve-related morbidity and mortality. CONCLUSIONS To avoid reoperations in octogenarians, the 10-year durability of current bioprostheses should be matched with the life expectancy of the particular patient. Bioprostheses should be used after 74 years in men and 78 years in women.

Reoperations for left atrioventricular valve dysfunction after repair of atrioventricular septal defect

OBJECTIVES Postoperative left atrioventricular valve (LAVV) dysfunction is known to be the principal risk factor influencing outcome after repair of all types of atrioventricular septal defect (AVSD). The purpose of the present study was to identify the risk factors for reoperation and to assess the outcomes after reoperation for LAVV dysfunction. METHODS Records of 412 patients who underwent anatomical repair for different types of AVSD from January 2000 to July 2012 were reviewed. The study group (n = 60) included 13 additional patients for whom repair ± LAVV reoperation was performed in a primary institution. Outcomes, independent risk factors, reoperation and death were analysed. RESULTS There were 7 early, (1.7%) and 1 late death. Forty-seven (11.4%) required 64 reoperations for LAVV dysfunction. The median delay for the first LAVV reoperation was 3.5 months (range: 5 days to 10.0 years). Unbalanced ventricles with small left ventricle [odds ratio (OR) = 4.06, 95% confidence interval (CI): 1.58-10.44, P = 0.004], double-orifice LAVV (OR = 5.04, 95% CI: 1.39-18.27, P = 0.014), prior palliative surgery (OR = 3.5, 95% CI: 1.14-10.8, P = 0.029) and discharge echocardiography documenting LAVV regurgitation grade >2 (OR = 21.96, 95% CI: 8.91-54.09, P < 0.001) were found to be independent risk factors for LAVV reoperation. Twelve-year survival and freedom from LAVV reoperation rates were, respectively, 96.1% (95% CI: 94.1-98.1) and 85.8% (95% CI: 81.3-90.3). Survival was significantly worse in patients who underwent LAVV reoperation (P < 0.001) and in those who underwent valve replacement vs valve repair (P = 0.020). CONCLUSION After AVSD repair, LAVV dysfunction appears to be the principal factor that influences outcome. It can usually be managed by repair. Need for multiple reoperations is not uncommon. Long-term outcome in patients with repaired LAVV is favourable.

Anomalous Origin of the Left Coronary Artery From the Pulmonary Artery Associated With Severe Left Ventricular Dysfunction: Results in Normothermia

BACKGROUND Repair of anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) carries a high risk of operation, particularly in those with poor left ventricular function. In this study, we assessed the outcomes of patients who presented with severe preoperative left ventricular dysfunction (shortening fraction <15%) who underwent the repair under normothermic bypass. METHODS Since September 2002, 21 infants with severe left ventricular dysfunction underwent surgical repair using a direct coronary reimplantation technique. Mean age of patients was 5.3 +/- 3.8 months. Moderate or severe mitral regurgitation present in 5 patients was not addressed at the operation. Repair was performed under normothermic cardiopulmonary bypass and myocardial protection was achieved by intermittent antegrade normothermic blood cardioplegia. RESULTS Mean cardiopulmonary bypass and cross-clamp times were 153.5 +/- 51 and 50 +/- 14.5 minutes, respectively. There was one (4.7%) early death because of sudden cardiac arrest 48 hours after successful weaning from mechanical ventilation. One patient required urgent left coronary artery stenting on the 34th postoperative day because of early reimplantation failure. There was no late death. Echocardiographic evaluation revealed a significant improvement in terms of shortening fraction (preoperative, 10.3 +/- 3.2% vs follow-up, 33 +/- 7.7%, p < 0.0001). CONCLUSIONS Our results suggest that the repair of anomalous origin of the left coronary artery from the pulmonary artery can be accomplished with acceptable mortality and morbidity rates even in patients having severely depressed left ventricular function. Normothermic cardiopulmonary bypass is safe and effective in children who have a limited tolerance to further ischemic insult.

Transcatheter Closure of Large Atrial Septal Defects Feasibility and Safety in a Large Adult and Pediatric Population

Background—Data are needed on the safety and efficacy of device closure of large atrial septal defects. Methods and Results—Between 1998 and 2013, 336 patients (161 children <15 years) with large, isolated, secundum atrial septal defects (balloon-stretched diameter ≥34 mm in adults or echocardiographic diameter >15 mm/m2 in children) were managed using the Amplatzer device, at the Marie Lannelongue Hospital. Transthoracic echocardiographic guidance was used starting in 2005 (n=219; 65.2%). Balloon-stretched diameter was >40 mm in 36 adults; mean values were 37.6±3.3 mm in other adults and 26.3±6.3 mm/m2 in children. Amplatzer closure was successful in 311 (92.6%; 95% confidence interval, 89%–95%) patients. Superior and posterior rim deficiencies were more common in failed than in successful procedures (superior, 24.0% versus 4.8%; P=0.002; and posterior, 32.0% versus 4.2%; P<0.001). Device migration occurred in 4 adults (2 cases each of surgical and transcatheter retrieval); in the 21 remaining failures, the device was unreleased and withdrawn. After a median follow-up of 10.0 years (2.5–17 years), all patients were alive with no history of late complications. Conclusions—Closure of large atrial septal defects using the Amplatzer device is safe and effective in both adults and children. Superior and posterior rim deficiencies are associated with procedural failure. Closure can be performed under transthoracic echocardiographic guidance in experienced centers. Early device migration is rare and can be safely managed by device extraction. Long-term follow-up showed no deaths or major late complications in our population of 311 patients.

Slide tracheoplasty in infant with congenital tracheal stenosis and tracheomalacia after esophageal atresia with tracheoesophageal fistula repair.

Slide tracheoplasty can be applied successfully to all types of long segment congenital tracheal stenosis. In case of short segment tracheal stenosis, direct resection and anastomosis is often preferred. We report a case illustrating a new side benefit of the slide tracheoplasty in a patient presenting a relatively short hypoplastic tracheal segment coexisting with tracheomalacia after EA with TEF repair.

T Cell deletion and unresponsiveness induced by intrathymic injection of staphylococcal enterotoxin B

Intrathymic injection of alloantigens appears to be the most efficient route to induce alterations of T cell reactivity. In the present study, we explored the modifications of Vbeta8.1, 8.2 T cell population and T cell reactivity in the thymus and in the spleen induced by intrathymic injection of staphylococcal enterotoxin B to adult mice. Vbeta8 antigen expression was investigated by flow cytometry analysis. T Cell reactivity was studied in vitro by the proliferative response to SEB. SEB induced a significant reduction in the percentage of mature Vbeta8+ T cells in the thymus (days 7-14), and in the spleen (days 7-28). Interestingly, this depletion occurs in the CD4- CD8+ cells in the thymus whereas in the CD4+ CD8- cells in the spleen. In parallel, the proliferative response to SEB but not to SEA was significantly decreased in the thymus on days 7 and 14, and in the spleen from day 7 to day 28. Moreover, this unresponsiveness was more pronounced in the spleen than in the thymus. Anergy was SEB-specific and fully reversed by exogenous IL-2. SEB injected intrathymically induced significantly more pronounced and more durable T cell alterations than intraperitoneal and subcutaneous injections. This may be related to the observation that after i.t. injection, SEB was detected both at a higher amount and for a longer period in the central and peripheral compartments. Our results clearly demonstrate that the intrathymic route is definitely the most efficient to induce not only thymic but also peripheral pivotal immune alterations in our model.