Damien Bonnet

Percutaneous replacement of pulmonary valve in a right-ventricle to pulmonary-artery prosthetic conduit with valve dysfunction

BACKGROUND Valved conduits from the right ventricle to the pulmonary artery are frequently used in paediatric cardiac surgery. However, stenosis and insufficiency of the conduit usually occur in the follow-up and lead to reoperations. Conduit stenting can delay surgical replacement, but it aggravates pulmonary insufficiency. We developed an innovative system for percutaneous stent implantation combined with valve replacement. METHODS A 12-year-old boy with stenosis and insufficiency of a prosthetic conduit from the right ventricle to the pulmonary artery underwent percutaneous implantation of a bovine jugular valve in the conduit. FINDINGS Angiography, haemodynamic assessment, and echocardiography after the procedure showed no insufficiency of the implanted valve, and partial relief of the conduit stenosis. There were no complications after 1 month of follow-up, and the patient is presently in good physical condition. INTERPRETATION We have shown that percutaneous valve replacement in the pulmonary position is possible. With further technical improvements, this new technique might also be used for valve replacement in other cardiac and non-cardiac positions.

Holt-oram syndrome is caused by mutations in TBX5, a member of the Brachyury (T) gene family

Holt-Oram syndrome is a developmental disorder affecting the heart and upper limb, the gene for which was mapped to chromosome 12 two years ago. We have now identified a gene for this disorder (HOS1). The gene (TBX5) is a member of the Brachyury (T) family corresponding to the mouse TbxS gene. We have identified six mutations, three in HOS families and three in sporadic HOS cases. Each of the mutations introduces a premature stop codon in the TBXS gene product. Tissue in situ hybridization studies on human embryos from days 26 to 52 of gestation reveal expression of TBXS in heart and limb, consistent with a role in human embryonic development.

Presence of increased stiffness of the common carotid artery and endothelial dysfunction in severely obese children: a prospective study

BACKGROUND Epidemiological studies suggest that obesity-induced atherosclerosis may start in childhood, but this process has never been demonstrated. We looked for arterial changes and investigated their relation to cardiovascular risk factors in obese children. METHODS Non-invasive ultrasonographic measurements were made in 48 severely obese children and 27 controls to investigate arterial mechanics and endothelial function. Plasma lipid concentrations, indices of insulin resistance, and body composition were assessed in the obese children. FINDINGS The obese children had significantly lower arterial compliance than the healthy controls (median 0.132 [0.022-0.273] vs 0.143 [0.112-0.237] mm(2).mm Hg; p=0.02) and lower distensibility (0.60 [0.10-1.00] vs 0.70 [0.50-1.10] mm Hg(-1).10(-2); p=0.0001). Conversely, the obese children had higher values than the controls for wall stress (3.36 [2.00-5.01] vs 2.65 [2.13-3.54] mm Hg.10(2); p=0.0001) and incremental elastic modulus (1.68 [0.72-10.8] vs 0.96 [0.64-1.47]; p=0.0001). Endothelium-dependent and independent function were also lower in the obese than in the control children. An android fat distribution was positively correlated with indices of insulin resistance and plasma triglyceride concentrations and was negatively correlated with plasma HDL-cholesterol concentration and arterial compliance. Endothelial dysfunction was correlated with low plasma apolipoprotein A-I and with insulin resistance indices. INTERPRETATION Severe obesity in children is associated with arterial wall stiffness and endothelial dysfunction. Low plasma apolipoprotein A-I, insulin resistance, and android fat distribution may be the main risk factors for these arterial changes, which are of considerable concern as possible early events in the genesis of atheroma.

Detection of Transposition of the Great Arteries in Fetuses Reduces Neonatal Morbidity and Mortality

BACKGROUND Transposition of the great arteries (TGA) is a life-threatening malformation in neonates, but it is amenable to complete repair. Prenatal detection, diagnosis, and early management may modify neonatal mortality and mortality. METHODS AND RESULTS Preoperative and postoperative morbidity and mortality were compared in 68 neonates with prenatal diagnosis and in 250 neonates with a postnatal diagnosis of TGA over a period of 10 years. The delay between birth and admission was 2+/-2.8 hours in the prenatal group and 73+/-210 hours in the neonatal group (P<0.01). Clinical condition at arrival, including metabolic acidosis and multiorgan failure, was worse in the neonatal group (P<0.01). Once in the pediatric cardiology unit, the management was identical in the 2 groups (atrioseptostomy, PGE1 infusion, operation date). Preoperative mortality was 15 of 250 (6%; 95% CI, 3% to 9%) in the neonatal group and 0 of 68 in the prenatal group (P<0.05). Postoperative morbidity was not different (25 of 235 versus 6 of 68), but hospital stay was longer in the neonatal group (30+/-17 versus 24+/-11 days, P<0.01). In addition, postoperative mortality was significantly higher in the neonatal group (20 of 235 versus 0 of 68, P<0.01); however, the known risk factors for operative mortality were identical in the 2 groups. CONCLUSIONS Prenatal diagnosis reduces mortality and morbidity in TGA. Prenatal detection of this cardiac defect must be increased to improve early neonatal management. In utero transfer of fetuses with prenatal diagnosis of TGA in an appropriate unit is mandatory.

Transcatheter Implantation of a Bovine Valve in Pulmonary Position A Lamb Study

BACKGROUND Pulmonary regurgitation can lead to severe right ventricular dysfunction, which is a delicate postoperative problem in the long-term follow-up of patients who had surgery for congenital heart diseases. Clinical conditions of patients suffering from pulmonary valve incompetence are improved by valve replacement with a prosthetic valve. To date, the surgical approach is the only option to replace a pulmonary valve. We report the first experience of percutaneous pulmonary valve implantation. METHODS AND RESULTS A fresh bovine jugular vein containing a native valve was sutured into a vascular stent and then cross-linked with a 0.6% glutaraldehyde solution for 36 hours. After being hand-crimped onto a balloon catheter, the device was inserted percutaneously according to standard stent-placing techniques. The valved stent was finally deployed in the position of the native pulmonary valve of the lamb. Hemodynamic evaluation was carried out before and 2 months after implantation. Anatomic evaluation was finally performed. Percutaneous pulmonary valve replacement was successful in 5 lambs. No complications were noted. Early and late angiographic and hemodynamic studies confirmed a good position of the stents with a competent valve at the end of the protocol. One stent was slightly stenotic, with macroscopically visible calcifications. CONCLUSIONS Nonsurgical implantation of pulmonary valves is possible in the lamb. This new technique is similar to standard stent implantation. Thus, it should be feasible in humans, in whom it will lead to a significant reduction of reoperations in patients in need of pulmonary valve replacement.

Recognition and management of fatty acid oxidation defects: A series of 107 patients

In a personal series of 107 patients, we describe clinical presentations, methods of recognition and therapeutic management of inherited fatty acid oxidation (FAO) defects. As a whole, FAO disorders appear very severe: among the 107 patients, only 57 are still living. Including 47 siblings who died early in infancy, in total 97 patients died, of whom 30% died within the first week of life and 69% before 1 year. Twenty-eight patients presented in the neonatal period with sudden death, heart beat disorders, or neurological distress with various metabolic disturbances. Hepatic presentations were observed in 73% of patients (steatosis, hypoketotic hypoglycaemia, hepatomegaly, Reye syndrome). True hepatic failure was rare (10%); cholestasis was observed in one patient with LCHAD deficiency. Cardiac presentations were observed in 51% of patients: 67% patients presented with cardiomyopathy, mostly hypertrophic, and 47% of patients had heart beat disorders with various conduction abnormalities and arrhythmias responsible for collapse, near-miss and sudden unexpected death. All enzymatic blocks affecting FAO except CPT I and MCAD were found associated with cardiac signs. Muscular signs were observed in 51% of patients (of whom 64% had myalgias or paroxysmal myoglobinuria, and 29% had progressive proximal myopathy). Chronic neurologic presentation was rare, except in LCHAD deficiency (retinitis pigmentosa and peripheral neuropathy). Renal presentation (tubulopathy) and transient renal failure were observed in 27% of patients. The diagnosis of FAO disorders is generally based on the plasma acylcarnitine profile determined by FAB-MS/MS from simple blood spots collected on a Guthrie card. Urinary organic acid profile and total and free plasma carnitine can also be very helpful, mostly in acute attacks. If there is no significant disturbance between attacks, the diagnosis is based upon a long-chain fatty acid loading test, fasting test, and in vitro studies of fatty acid oxidation on fresh lymphocytes or cultured fibroblasts. Treatment includes avoiding fasting or catabolism, suppressing lipolysis, and carnitine supplementation. The long-term dietary therapy aims to prevent periods of fasting and restrict long-chain fatty acid intake with supplementation of medium-chain triglycerides. Despite these therapeutic measures, the long-term prognosis remains uncertain.

Trends in prenatal diagnosis, pregnancy termination, and perinatal mortality of newborns with congenital heart disease in France, 1983-2000: a population-based evaluation

Objective. To examine population-based overall and malformation-specific trends in the prenatal diagnosis, pregnancy termination, and perinatal mortality for congenital heart disease (CHD) during a period of rapid progress in prenatal diagnosis and medical management of CHD and to explore the impact of prenatal diagnosis on early neonatal mortality for specific (isolated) cardiac malformations. Methods. A total of 1982 cases of CHD, which were not associated with a known chromosomal anomaly, were obtained from the Paris Registry of Congenital Malformations. Main outcome measures were trends in the proportions diagnosed and terminated before birth, stillbirth, and early (<1 day, 1-week) neonatal mortality for (1) all cases; (2) all cases excluding isolated ventricular septal defects; and (3) malformation-specific trends for transposition of great arteries, hypoplastic left heart syndrome, coarctation of aorta, and tetralogy of Fallot. Analyses included cusum and binomial regression models for analysis of the trends during 1983–2000. Results. Prenatal diagnosis rates for CHD increased from 23.0% (95% confidence interval [CI]: 19.0–27.4) in 1983–1988 to 47.3% (95% CI: 43.8–50.8) in 1995–2000. Termination rates increased between 1983 and 1989 (9.9%; 95% CI: 7.2–13.2) and 1989 and 1994 (14.7%; 95% CI: 12.3–17.4) but seemed to remain stable thereafter. Other than for hypoplastic left heart syndrome, pregnancy termination was exceptional for the other 3 specific malformations examined. Early neonatal mortality decreased to less than one third in the period 1995–2000 as compared with 1983–1989 (risk ratio, first-week mortality: 0.31; 95% CI: 0.18–0.53). First-week mortality was significantly lower for cases of transposition of great arteries that were diagnosed before birth (risk difference: 15.4%; 95% CI: 4.0–26.7). Conclusions. Progress in clinical management, together with policies for increased access to prenatal diagnosis, has resulted in both a substantial increase in the prenatal diagnosis and considerable reductions in early neonatal mortality of CHD in the Parisian population.

Idebenone and reduced cardiac hypertrophy in Friedreich's ataxia

Background: Friedreichs ataxia encodes a protein of unknown function, frataxin. The loss of frataxin is caused by a large GAA trinucleotide expansion in the first intron of the gene, resulting in deficiency of a Krebs cycle enzyme, aconitase, and of three mitochondrial respiratory chain complexes (I–III). This causes oxidative stress. Idebenone, a short chain quinone acting as an antioxidant, has been shown to protect heart muscle against oxidative stress in some patients. Objective: To assess the efficiency of idebenone on cardiac hypertrophy in Friedreichs ataxia. Design: Prospective, open trial. Setting: Tertiary care centre. Methods: Idebenone (5 mg/kg/day) was given orally to 38 patients with Friedreichs ataxia aged 4–22 years (20 males, 18 females). Cardiac ultrasound indices were recorded before and after idebenone treatment. Results: After six months, cardiac ultrasound indicated a reduction in left ventricular mass of more than 20% in about half the patients (p < 0.001). The shortening fraction was initially reduced in six of the 38 patients (by between 11–26%) and it improved in five of these. In one patient, the shortening fraction only responded to 10 mg/kg/day of idebenone. No correlation was found between responsiveness to idebenone and age, sex, initial ultrasound indices, or the number of GAA repeats in the frataxin gene. Conclusions: Idebenone is effective at controlling cardiac hypertrophy in Friedreichs ataxia. As the drug has no serious side effects, there is a good case for giving it continuously in a dose of 5–10 mg/kg/day in patients with Friedreichs ataxia at the onset of hypertrophic cardiomyopathy.

Circulating Endothelial Cells A New Candidate Biomarker of Irreversible Pulmonary Hypertension Secondary to Congenital Heart Disease

Background— Congenital heart disease can be complicated by pulmonary arterial hypertension (PAH), the reversibility of which is often difficult to predict. We recently reported a lung biopsy study showing impaired apoptotic regulation of endothelial cells in irreversible PAH. The objective of the present study was to identify noninvasive biomarkers of endothelial turnover that could be used to identify congenital heart disease patients at risk of irreversible PAH. Methods and Results— Circulating endothelial cells (CECs) isolated with CD146-coated beads and circulating CD34+CD133+ progenitor cells (CPCs) were quantified in peripheral vein, pulmonary artery, and pulmonary vein blood samples from 26 patients with congenital heart disease (16 with reversible PAH [median age 2 years] and 10 with irreversible PAH [median age 9 years]) and 5 control patients. Surgical lung biopsy was performed in 19 cases. As expected, endothelial remodeling was observed in irreversible PAH but not in reversible PAH. CEC and CPC numbers were each similar in the 3 types of blood samples. CEC numbers were significantly higher in patients with irreversible PAH (median 57 CEC/mL) than in patients with reversible PAH and control subjects (median 3 CEC/mL in the 2 groups). In contrast, CPC numbers did not differ among patients with irreversible or reversible PAH and control subjects (median 84, 64, and 44 CPC/105 lymphocytes, respectively, in the 3 groups). Conclusions— Irreversible PAH in congenital heart disease is associated with endothelial damage and with increased circulating endothelial cell counts. The present study suggests that CECs could be a valuable tool to define therapeutic strategies in congenital heart disease patients with PAH.

Arterial Mechanical Changes in Children With Familial Hypercholesterolemia

Atherosclerosis is preceded by a phase of changes in the arterial wall that could have functional consequences even before the appearance of atheromatous changes. We hypothesized that early alterations of the mechanical properties of the arterial wall could precede clinical and echographic modifications. We used an automatic, computerized, ultrasonic procedure to evaluate geometric and mechanical characteristics of the common carotid artery (CCA) in normotensive children with primary familial class IIA hypercholesterolemia (FH; n=30; mean±SD age, 11±2 years old; mean±SD systolic/diastolic blood pressure, 109±9/55±7 mm Hg). These subjects were compared with age-matched, nonobese control subjects (n=27; 11±3 years old; 112±10/55±7 mm Hg). Noninvasive ultrasonic measurements were performed by the same investigator to measure the CCA luminal systolic and diastolic diameters and intima-media thickness (IMT). The cross-sectional compliance, cross-sectional distensibility, and the incremental elastic modulus of the CCA wall were then calculated. Finally, we assessed the degree of reactive hyperemia in the brachial artery produced after distal cuff occlusion and release. The changes in brachial arterial diameter in response to reactive hyperemia (endothelium-dependent dilation) and to glyceryltrinitrate (endothelium-independent dilation) were then measured. In patients with FH, we observed a significant reduction of systodiastolic variations in diameter (by 20%, P <0.001) without a significant difference in IMT. Cross-sectional compliance and cross-sectional distensibility were significantly reduced in FH subjects (by 15%, P <0.05 and 19%, P <0.01, respectively). In parallel, the incremental elastic modulus was significantly increased (by 27%, P <0.01) in children with FH. No correlation was evident between the carotid incremental modulus and either IMT or plasma low density lipoprotein cholesterol level. There was no difference in diameter of the brachial artery at rest in control and FH subjects (3.0±0.5 versus 3.0±0.4 mm). The reactive hyperemia and glyceryltrinitrate dilation were also similar in the 2 groups. However, the flow-mediated dilation of the brachial artery was smaller in the FH subjects (4.2±2.9%) than in controls (9.0±3.1%, P <0.001). In FH, endothelium-dependent dilation was negatively correlated with the plasma low density lipoprotein cholesterol level (P <0.04). These results indicate that increased stiffness of the CCA wall in children with FH is independent of blood pressure and could be related to endothelial dysfunction. Thus, alterations in CCA wall mechanics could be early and easily measurable markers of atheromatous changes in the arterial wall.