Right ventricular function during exercise in children after heart transplantation.

Aims: Right ventricular (RV) dysfunction is a common problem after heart transplant (HTx). In this study, we used semi-supine bicycle ergometry (SSBE) stress echocardiography to evaluate RV systolic and diastolic reserve in paediatric HTx recipients. Methods and results: Thirty-nine pediatric HTx recipients and 23 controls underwent stepwise SSBE stress echocardiography. Colour tissue doppler imaging (TDI) peak systolic (s') and peak diastolic (e') velocities, myocardial acceleration during isovolumic contraction (IVA), and RV free wall longitudinal strain were measured at incremental heart rates (HR). The relationship with increasing HR was evaluated for each parameter by plotting values at each stage of exercise versus HR using linear and non-linear regression models. At rest, HTx recipients had higher HR with lower TDI velocities (s': 5.4 ± 1.7 vs. 10.4 ± 1.8 cm/s, P < 0.001; e': 6.4 ± 2.2 vs.12 ± 2.4 cm/s, P < 0.001) and RV IVA values (IVA: 1.2 ± 0.4 vs. 1.6 ± 0.8 m/s2, P = 0.04), while RV free wall longitudinal strain was similar between groups. At peak exercise, HR was higher in controls and all measurements of RV function were significantly lower in HTx recipients, except for RV free wall longitudinal strain. When assessing the increase in each parameter vs. HR, the slopes were not significantly different between patients and controls except for IVA, which was lower in HTx recipients. Conclusion: In pediatric HTx recipients RV systolic and diastolic functional response to exercise is preserved with a normal increase in TDI velocities and strain values with increasing HR. The blunted IVA response possibly indicates a mildly decreased RV contractile response but it requires further investigation.

Impact of surgical pulmonary valve replacement on ventricular mechanics in children with repaired tetralogy of Fallot.

Impaired ventricular myocardial mechanics are observed in patients with repaired tetralogy of Fallot (rTOF). Effects of pulmonary valve replacement (PVR) on ventricular remodeling are controversial. The objective was to assess the impact of surgical PVR on ventricular mechanics in pediatric patients after rTOF. Speckle-tracking analysis was performed in 50 rTOF children, aged 12.6 ± 3.3 years, pre-operatively and 14.5 ± 2.2 months post-PVR. Early post-operative studies 2.2 ± 0.6 months post-PVR were performed in 28 patients. Cardiac magnetic resonance (CMR) pre- and post-PVR was collected. Mid-term post-PVR right ventricular (RV) longitudinal strain increased above pre-operative strain (-19.2 ± 2.7 to -22.0 ± 3.0%, p < 0.001) with increases observed in individual RV segments. Left ventricular (LV) strain did not differ at medium-term follow-up. LV and RV longitudinal strain was reduced early post-operatively, followed by recovery of biventricular systolic strain by mid-term follow-up. CMR RV end-diastolic indexed volumes correlated with RV strain pre-operatively (r = 0.432, p = 0.005) and at mid-term follow-up (r = 0.532, p = 0.001). Volume-loaded RVs had reduced early RV basal longitudinal strain compared to pressure-loading conditions. Reversed basal counterclockwise rotation was associated with lower mid-term global LV and basal RV strain compared to patients with normal rotation. An increase in mid-term global and regional RV strain beyond pre-operative values suggests positive RV remodeling and adaptation occurs in children post-PVR. Patients with larger pre-operative RV volumes had lower RV strain post-operatively. The impact of LV rotation on RV mechanics highlights the presence of ventriculo-ventricular interactions. These findings have important clinical implications in pediatric rTOF patients towards identifying pre-operative factors that predict RV post-operative remodeling.

[Pulmonary stenosis and atresia with intact ventricular septum]. / Sténose pulmonaire et atrésie pulmonaire à septum interventriculaire intact.

Pulmonary atresia and critical pulmonary stenosis with intact ventricular septum includes a wide spectrum of cardiopathies with great morphological heterogeneity. The pulmonary valve may be completely atretic or may contain a puncture hole if stenosis is present. The obstruction may be membranous and/or muscular. All components of the right ventricle can be affected, even the coronary circulation with ventriculocoronary connections and stenosis or atresia of the pulmonary arteries. Prenatal diagnosis is made when the right ventricle is hypoplastic and hypertrophic. The pulmonary valve is thickened and the pulmonary artery is perfused retrogradely through the ductus arteriosus. Right ventriculocoronary connections may sometimes be seen with fetal echocardiography. Postnatal survival depends on the patency of the ductus arteriosus, requiring prostaglandin E1 infusion. When hypoplastic right ventricle and/or ventricle-dependent coronary circulation exists, biventricular circulation is not possible. In these cases, surgical treatment is palliative. In cases with well-developed right ventricle, transcatheter therapy is usually provided with perforation and balloon dilation of the pulmonary valve. In cases of muscular obstruction of the right ventricle outflow tract, surgery may be considered as first-line therapy. In case of prenatal diagnosis, the medical termination of pregnancy is possible when severe right ventricular hypoplasia exists, precluding biventricular circulation. Postnatally, the prognosis of the patients is highly variable, mainly related to the size of the right cavities and the presence of coronary anomalies.

[A monocenter experience of ventricular septal defects treated by catherization]. / Expérience monocentrique de la fermeture par cathétérisme interventionnel des communications interventriculaires.

INTRODUCTION: Studies on ventricular septal defects closure by catheterization confirm its feasibility without reporting clearly the indications and difficulties encountered. PATIENTS AND RESULTS: From 2001 to end-2006, 22 patients benefited from 26 ventricular septal defects closure (15 muscular and 7 membranous) at a median age and weight of 2.1 years and 12.5 kg, respectively. A perventricular catheterization was performed in 2 cases. Eighteen patients (82%) benefited from 21 prostheses with success. The closure was associated to surgery in 9 cases (41%) whereas it substituted surgery in the other 13 cases (59%). The median duration of the procedure was significantly longer in case of muscular ventricular septal defects (215 min (175-510) vs. 170 min (120-225), p=0.04). Major complications are reported in 5 cases out of 26 catheterization (19%), including one death related to conduction block, occurring after the implantation of two prostheses in a patient with aortopulmonary transposition. All other associated cardiac diseases have been corrected. A prosthetic emboli occurred in one case, 1.5 months after implantation. It had been retrieved by catheterization. Two patients died afterwards from non-procedure-related causes. After a median follow-up of 1.1 years, the 17 other patients remained asymptomatic. One child with a perimembranous prosthesis presents a paroxystic atrio-ventricular block. CONCLUSION: Even though indispensable for the curative treatment of several congenital cardiac diseases including non-operable ventricular septal defects, this procedure is related to a substantial rate of mortality and morbidity. The risk of atrio-ventricular block must be adequately considered in case of membranous ventricular septal defects.

[Long-term results of complete atrio-ventricular canal correction]. / Résultats à long terme du traitement chirurgical du canal atrioventriculaire complet.

OBJECTIVES: To assess the prognosis of surgically corrected complete atrio-ventricular canal and determine risk factors for death and redo surgery. PATIENTS: and method: From January 1984 to March 2006, 126 patients were distributed in 3 groups according to their date of intervention: group I (1984-1991), group II (1992-1999) and group III (2000-2006). They were operated at mean age of 8.35 + 13.3 months. Down syndrome was present in 99 patients (79%). A partial or total closure of the left atrio-ventricular valvular cleft was performed in 47 patients (37%). RESULTS: The in-hospital mortality was at 14.28% (18 patients), including 23.7% in group I, 16.2% in group II and 4.4% in group III (p=0.06). The predictive factors of survival were the Down syndrome (p<0.05) and surgery of the left atrio-ventricular valvular cleft (p=0.05). An early reoperation was required in 6 cases, for a severe leak of this valve (n=4) or an important residual shunt (n=2). After a mean follow-up of 9.5+6.9 years, the survival rate was at 83.6% and 10 patients (9.9%) had a redo surgery for a leak of the left atrio-ventricular valve (n=6) or sub-aortic stenosis (n=4). The rate of no-redo surgery for valve insufficiency was at 94.2% at 5 years, 91.1% at 10 years and 87.6% at 15 years. CONCLUSION: The surgical treatment of complete atrio-ventricular canal became more and more efficient with poor rates of mortality and redo surgery during these last years. The closure of the left atrio-ventricular valve cleft, mostly partial, is frequently performed. Patients with the Down syndrome have a better vital prognosis and lower rates of long-term redo surgery.

[Rehabilitation of hypoplastic pulmonary arteries in pulmonary atresia with ventricular septal defect. Medium term results]. / Réhabilitation des artères pulmonaires hypoplasiques dans l'atrésie pulmonaire avec communication interventriculaire. Résultats à moyen terme.

The treatment of pulmonary atresia with ventricular septal defect, hypoplasia of the native pulmonary arteries and major aorto-pulmonary collaterals is controversial with a wide range of options from symptomatic treatment to surgical correction, but usually unifocal surgery. However, the collateral vessels used in the reconstruction are often tortuous and stenosed, resulting in a problematic haemodynamic result. The authors report the results of medico-surgical rehabilitation of the native pulmonary arteries in three stages. Since 1990, patients with an average Nakata index of 27.5 +/- 16.7 mm2/m2 underwent elective surgical connection of the native pulmonary arteries to the right ventricle (1st stage) followed by their rehabilitation with catheter occlusion of the collaterals (2nd stage) with the aim of preparing surgical correction (3rd stage). The first surgical stage at an median age of 5 months (0.1 to 25.2) was complicated by one death. After an average of 2.1 +/- 1 catheterisations, 17 patients underwent surgical correction at an median age of 2.18 (0.6 to 10.3) years with an average Nakata index of 207 +/- 91 mm2/m2. All survived surgery with three late deaths in patients with poor haemodynamic results (right ventricular/left ventricular pressure ratio>80%). After an median follow-up of 9.2 (3.5 to 17) years, the 14 survivors are in NYHA Class I or II with a good haemodynamic result in 10 patients. The authors conclude that despite some late deaths and raised right ventricular and pulmonary artery pressures in a minority of patients, the rehabilitation of the pulmonary arteries is an effective management of this cardiopathy.

[Value of the Norwood-Sano compared with the classical Norwood procedure in hypoplastic left heart syndrome]. / Intérêt de l'intervention de Norwood-Sano par rapport à l'intervention classique de Norwood dans l'hypoplasie du coeur gauche.

Palliative treatment of the hypoplastic left heart syndrome is rarely practiced in France because of the poor prognosis of the first surgical stage of the Norwood procedure. The recent modification proposed by Sano seems to give more promising results. The authors report their experience with the Norwood-Sano procedure compared with the classical Norwood procedure in 13 neonates with hypoplasia of the left heart. From 1999 to 2005, 8 patients underwent the classical Norwood procedure (1999-2001) and 5 had the Sano modification (2002-2005). During the preoperative period, there was 1 case of a very restrictive interatrial septum and 5 patients required mechanical ventilation. The patients were operated at an average age of 8.5 +/- 12 days. The results showed that survival after the first surgical stage was significantly better with the Sano modification (12.5% versus 80%; p= 0.03). All patients who survived the first stage went on to the second stage with a bi-directional right superior cavo-pulmonary derivation at an average of 6.1 +/- 2.4 months. Despite the infundibulotomy of the Sano modification, no arrhythmia or right ventricular dysfunction was observed after an average follow-up of 21.7 +/- 7.6 months. The authors conclude that the Sano modification improved survival of patients with hypoplasia of the left heart after the first palliative surgical procedure. The long-term follow-up of patients operated by this technique should particularly look out for arrhythmias and right ventricular dysfunction.